Дисертації: "Wastes conversion"

1

Walling, Samuel. "Conversion of magnesium bearing radioactive wastes into cementitious binders." Thesis, University of Sheffield, 2016. http://etheses.whiterose.ac.uk/13436/.

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The UK radioactive waste inventory contains sizeable portions of magnesium hydroxide rich Magnox sludges due to corrosion of historic wastes. These require disposal in suitable wasteforms, with one potential being solidification in a composite Portland cement matrix. This thesis investigates magnesium hydroxide as a key component in the production of a cementitious binder, attempting to maximise waste loading and improve wasteform integrity through integral usage of these wastes. Hydrated magnesium silicate cements were produced through reaction with amorphous silica, creating stable products comprising a poorly crystalline M-S-H gel. The formulations for this product were optimised, water contents reduced through the use of a polyphosphate dispersant, and the nature of the M-S-H binder investigated further. This was determined to be a lizardite-like structure, which is a stable mineral. This system was modified through the addition of sodium aluminate, resulting in formulations with varying ratios of silicon to aluminium, each of which produced various zeolitic phases along with a magnesium aluminium hydrotalcite phase. This addition improved the setting characteristics of the binders, but did not produce any additional magnesium silicates binders. Additionally to this, sodium carbonate activated slag cement binders blended with magnesium hydroxide were assessed. These were slower setting, low heat cements which formed stable mineral phases, largely unaffected by the addition of magnesium hydroxide. The chemistry of these binders was assessed over an 18 month period, remaining stable throughout. Ultimately it was proved that magnesium hydroxide can be utilised to form cementitious binders, but only in the absence of competing calcium based binding systems.

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2

Bernhart, Matthew. "Characterization of poultry litter for storage and process design." Auburn, Ala., 2007. http://repo.lib.auburn.edu/2007%20Spring%20Theses/BERNHART_MATTHEW_25.pdf.

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3

Gilbert, Christopher Donald. "Non-Newtonian conversion of emulsion liquid membranes in the extraction of lead and zinc from simulated wastewater." Diss., Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/10911.

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4

Du, Bowen Chambliss C. Kevin. "Effect of varying feedstock-pretreatment chemistry combinations on the production of potentially inhibitory degradation products in biomass hydrolysates." Waco, Tex. : Baylor University, 2009. http://hdl.handle.net/2104/5319.

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5

Serutla, Bokhabane Tlotliso Violet. "Potential for energy recovery and its economic evaluation from a municipal solid wastes landfill in Cape Town." Thesis, Cape Peninsula University of Technology, 2016. http://hdl.handle.net/20.500.11838/2463.

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Thesis (MTech (Chemical Engineering))--Cape Peninsula University of Technology, 2016.
Landfill gases, principally methane, CH4 are produced from the decomposition of the municipal solid wastes deposited on landfill sites. These gases can be captured and converted into usable energy or electricity which will assist in addressing energy needs of South Africa. Its capture also reduces the problems associated with greenhouse gases. The aim of this study is to estimate gases that can be produced from the Bellville landfill site in Cape Town. The landfill gas capacity was estimated using Intergovernmental Panel on Climate Change (IPCC) model. The IPCC model showed that 48 447m3/year of landfill gas capacity was determined only in 2013. The LFGTE process plant is designed in a manner of purifying landfill gas, which at the end methane gets up being the only gas combusted. As a matter of fact 14 544kg/year of gases which consists mainly methane gets combusted. The average energy that can be produced based on the generated landfill gas capacity (methane gas) is 1,004MWh/year. This translates to R1. 05million per year at Eskom’s current tariff of R2.86 /kWh) including sales from CO2 which is a by-product from the designed process plant. A LFGTE process plant has been developed from the gathered information on landfill gas capacity and the amount of energy that can be generated from the gas. In order, to start-up this project the total fixed capital costs of this project required amounted up to R2.5 million. On the other hand, the project made a profit amounted to R3.9million, the Net profit summed up to R1. 3million and the payback time of Landfill Gas ToEnergy (LFGTE) project is 4years.The break-even of the project is on second year of the plant’s operation. The maximum profit that this project can generate is around R1. 1million. The life span of the plant is nine years. Aspen plus indicated that about 87% of pure methane was separated from CO2 and H2S for combustion at theabsorption gas outletstream. I would suggest this project to be done because it is profitable when by-products such as CO2 sales add to the project’s revenues.

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6

Shehata, Asmaa. "Engineering Properties, Micro- and Nano-Structure of Bentonite-Sand Barrier Materials in Aggressive Environments of Deep Geological Repository for Nuclear Wastes." Thesis, Université d'Ottawa / University of Ottawa, 2015. http://hdl.handle.net/10393/32499.

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Canada produces about one-third of the global supply of medical radioisotopes. The nuclear power reactors in Ontario, Quebec and New Brunswick have generated about 17 percent of the electricity in the country every year (NWMO, 2010; Noorden; 2013). Since the 1960s, more than 2 million used (or spent) fuel bundles (high-level radioactivity) and 75,000 m³ of low- and intermediate-level radioactive waste have been produced, which is increasing by 2000 to 3000 m³ every year after reducing the processed volume (Jensen et al., 2009). More than 30 countries around the world, including Canada, have proposed construction of very deep geological repositories (DGRs) to store this nuclear waste for design periods 1,000,000 years. DGR concepts under development in Canada (the DGR is likely to be constructed in Ontario) are based on a multi-barrier system (NWMO, 2012). A crucial component of the multi-barrier system is the engineered barrier system (EBS), which includes a buffer, backfill, and tunnel sealing materials to physically, chemically, hydraulically and biologically isolate the nuclear waste. Bentonite-based material has been chosen for this critical use because of its high swelling capacity, low hydraulic conductivity, and for its good ability to retain radionuclides in the case of failed canisters. However, the presence of bentonite-based material in DGRs, surrounded by an aggressive environment of underground saline water, nuclear waste heat decay, and corrosion products under confining stress, may lead to mineralogical changes. Consequently, the physical and physiochemical properties of bentonite-based materials may change, which could influence the performance of bentonite in an EBS as well as the overall safety of DGRs. The objective of this research is to investigate the impact of the underground water salinity, heat generated by nuclear waste, and corrosion products of nuclear waste containers in Ontario on the engineering and micro-/nano-structural properties of bentonite-sand engineered barrier materials. Free-swelling, swelling pressure and hydraulic conductivity tests have been performed on bentonite-sand mixtures subjected to various chemical (groundwater chemistry; corrosion water with iron as a corrosion product) and thermal (heat generated) conditions. Several techniques of micro- and nano-structural analyses, such as x-ray diffraction (XRD), X-Ray microanalysis (DES), surface area and pore size distribution analyses (BET, BJH) and differential gravimetric (TGA and DTG) analyses have also been conducted on the bentonite-sand materials. Valuable results have been obtained for better understanding the durability and performance of the bentonite-sand barrier for the DGR which may be located in Ontario. The obtained results have shown that the groundwater chemistry and corrosion products of the nuclear containers significantly deteriorate the swelling and permeability properties of the tested bentonite-sand barrier materials, while temperature has little or no effect.

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7

Swart, Shanna. "Nanofiber immobilized cellulases and hemicellulases for fruit waste beneficiation." Thesis, Rhodes University, 2015. http://hdl.handle.net/10962/d1017914.

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8

Бухкало, Світлана Іванівна. "Моделювання процесів інноваційних енерготехнологій утилізації полімерів". Thesis, Одеська національна академія харчових технологій, 2017. http://repository.kpi.kharkov.ua/handle/KhPI-Press/31203.

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Розглянуто деякі особливості використання ТПВ на комплексному підприємстві, яке може забезпечувати всі свої енергетичні потреби самостійно. Дослідження спрямовані на вивчення таких питань, як розробка моделей утилізації-модифікації полімерної частини ТПВ або тари та пакування. При цьому враховувалися фактори вибору науково-обґрунтованих методів переробки та утилізації полімерів; розробку необхідних технологічних схем і устаткування для переробки полімерних відходів; вибір підприємств для реалізації утилізації полімерів і виду енергетичних ресурсів для реалізації цих проектних рішень.
Some features of the possibilities of solving evidence-based problems of improving the use of wastes of different industries on a complex enterprise that can provide all its energy needs alone. The problem of wastes utilization and recycling is present as complex research and analysis of energy- and resource saving processes for treatment of polymer wastes of various origin. The research focused on the study of issues such as the development of models of waste-modifying polymer. The investigation are focused in researching such problems as selection of scientific based methods of wastes to be utilized or recycled; the development of appropriated process flow sheets and choice of modifications additives and equipment for polymers waste recycling. The choice of appropriate plants with selected energy resources is very important for projects realization.

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9

Gama, Repson. "A lignocellulolytic enzyme system for fruit waste degradation : commercial enzyme mixture synergy and bioreactor design." Thesis, Rhodes University, 2014. http://hdl.handle.net/10962/d1013073.

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Studies into sources of alternative liquid transport fuel energy have identified agro-industrial wastes, which are lignocellulosic in nature, as a potential feedstock for biofuel production against the background of depleting nonrenewable fossil fuels. In South Africa, large quantities of apple and other fruit wastes, called pomace, are generated from fruit and juice industries. Apple pomace is a rich source of cellulose, pectin and hemicellulose, making it a potential target for utilisation as a lignocellulosic feedstock for biofuel and biorefinery chemical production. Lignocellulosic biomass is recalcitrant in nature and therefore its degradation requires the synergistic action of a number of enzymes such as cellulases, hemicellulases, pectinases and ligninases. Commercial enzyme cocktails, containing some of these enzymes, are available and can be used for apple pomace degradation. In this study, the degradation of apple pomace using commercial enzyme cocktails was investigated. The main focus was the optimisation of the release of sugar monomers that could potentially be used for biofuel and biorefinery chemical production. There is no or little information reported in literature on the enzymatic degradation of fruit waste using commercial enzyme mixtures. This study first focused on the characterisation of the substrate (apple pomace) and the commercial enzyme cocktails. Apple pomace was found to contain mainly glucose, galacturonic acid, arabinose, galactose, lignin and low amounts of xylose and fructose. Three commercial enzyme cocktails were initially selected: Biocip Membrane, Viscozyme L (from Aspergillus aculeatus) and Celluclast 1.5L (a Trichoderma reesei ATCC 26921 cellulase preparation). The selection of the enzymes was based on activities declared by the manufacturers, cost and local availability. The enzymes were screened based on their synergistic cooperation in the degradation of apple pomace and the main enzymes present in each cocktail. Viscozyme L and Celluclast 1.5L, in a 50:50 ratio, resulted in the best degree of synergy (1.6) compared to any other combination. The enzyme ratios were determined on Viscozyme L and Celluclast 1.5L based on the protein ratio. Enzyme activity was determined as glucose equivalents using the dinitrosalicylic acid (DNS) method. Sugar monomers were determined using Megazyme assay kits. There is limited information available on the enzymes present in the commercial enzyme cocktails. Therefore, the main enzymes present in Viscozyme L and Celluclast 1.5L were identified using different substrates, each targeted for a specific enzyme and activity. Characterisation of the enzyme mixtures revealed a large number of enzymes required for apple pomace degradation and these included cellulases, pectinases, xylanases, arabinases and mannanases in different proportions. Viscozyme L contained mainly pectinases and hemicellulases, while Celluclast 1.5L displayed largely cellulase and xylanase activity, hence the high degree of synergy reported. The temperature optimum was 50ºC for both enzyme mixtures and pH optima were observed at pH 5.0 and pH 3.0 for Viscozyme L and Celluclast 1.5L, respectively. At 37ºC and pH 5.0, the enzymes retained more that 90% activity after 15 days of incubation, allowing the enzymes to be used together with less energy input. The enzymes were further characterised by determining the effect of various compounds, such as alcohols, sugars, phenolic compounds and metal ions at various concentrations on the activity of the enzymes during apple pomace hydrolysis. Apart from lignin, which had almost no effect on enzyme activity, all the compounds caused inhibition of the enzymes to varying degrees. The most inhibitory compounds were some organic acids and metal ions, as well as cellobiose and xylobiose. Using the best ratio for Viscozyme L and Celluclast 1.5L (50:50) for the hydrolysis of apple pomace, it was observed that synergy was highest at the initial stages of hydrolysis and decreased over time, though the sugar concentration increased. The type of synergy for optimal apple pomace hydrolysis was found to be simultaneous. There was no synergy observed between Viscozyme L and Celluclast 1.5L with ligninases - laccase, lignin peroxidase and manganese peroxidase. Hydrolysing apple pomace with ligninases prior to addition of Viscozyme L and Celluclast 1.5L did not improve degradation of the substrate. Immobilisation of the enzyme mixtures on different supports was performed with the aim of increasing stability and enabling reuse of the enzymes. Immobilisation methods were selected based on the chemical properties of the supports, availability, cost and applicability on heterogeneous and insoluble substrate like apple pomace. These methods included crosslinked enzyme aggregates (CLEAs), immobilisation on various supports such as nylon mesh, nylon beads, sodium alginate beads, chitin and silica gel beads. The immobilisation strategies were unsuccessful, mainly due to the low percentage of immobilisation of the enzyme on the matrix and loss of activity of the immobilised enzyme. Free enzymes were therefore used for the remainder of the study. Hydrolysis conditions for apple pomace degradation were optimised using different temperatures and buffer systems in 1 L volumes mixed with compressed air. Hydrolysis at room temperature, using an unbuffered system, gave a better performance as compared to a buffered system. Reactors operated in batch mode performed better (4.2 g/L (75% yield) glucose and 16.8 g/L (75%) reducing sugar) than fed-batch reactors (3.2 g/L (66%) glucose and 14.6 g/L (72.7% yield) reducing sugar) over 100 h using Viscozyme L and Celluclast 1.5L. Supplementation of β- glucosidase activity in Viscozyme L and Celluclast 1.5L with Novozyme 188 resulted in a doubling of the amount of glucose released. The main products released from apple pomace hydrolysis were galacturonic acid, glucose and arabinose and low amounts of galactose and xylose. These products are potential raw materials for biofuel and biorefinery chemical production. An artificial neural network (ANN) model was successfully developed and used for predicting the optimum conditions for apple pomace hydrolysis using Celluclast 1.5L, Viscozyme L and Novozyme 188. Four main conditions that affect apple pomace hydrolysis were selected, namely temperature, initial pH, enzyme loading and substrate loading, which were taken as inputs. The glucose and reducing sugars released as a result of each treatment and their combinations were taken as outputs for 1–100 h. An ANN with 20, 20 and 6 neurons in the first, second and third hidden layers, respectively, was constructed. The performance and predictive ability of the ANN was good, with a R² of 0.99 and a small mean square error (MSE). New data was successfully predicted and simulated. Optimal hydrolysis conditions predicted by ANN for apple pomace hydrolysis were at 30% substrate (wet w/v) and an enzyme loading of 0.5 mg/g and 0.2 mg/mL of substrate for glucose and reducing sugar, respectively, giving sugar concentrations of 6.5 mg/mL and 28.9 mg/mL for glucose and reducing sugar, respectively. ANN showed that enzyme and substrate loadings were the most important factors for the hydrolysis of apple pomace.

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10

Amponsah, Nana Yaw. "Contribution à la théorie de l'éMergie : application au recyclage." Phd thesis, Ecole des Mines de Nantes, 2011. http://tel.archives-ouvertes.fr/tel-00653840.

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Le développement continu d'outils pour mesurer le développement durable a conduit à la théorie éMergétique. L'éMergie d'une ressource ou d'un produit est définie en convertissant toutes les ressources (matières premières) et les entrées d'énergie sous la forme de leurs équivalents énergétiques solaires (solar energy unit seJ), cf Odum (1996, 2000). L'objectif principal de cette thèse est d'adapter la méthode d'analyse éMergétique aux pratiques de recyclage industriel. La principale contribution scientifique de cette étude peut être résumée comme suit: contribution à la théorie éMergétique en temps discret appliquée au recyclage. Sous certaine hypothèses, l'émergie d'un produit recyclé peut être exprimée sous la forme d'une série géométrique. L'éMergétique d'un produit se détériorant, il existe un prix éMergétique au recyclage et une analogie avec l'énoncé de Carnot peut être faite. En conséquence, un nouveau "facteur" est introduit, ce dernier peut être inclus dans les tables d'évaluation éMergétique, pour tenir compte des accroissements de transformité dû aux recyclages multiples. Enfin, l'approche développée est appliquée avec succès à l'utilisation de matériaux de recycle dans un bâtiment basse énergie.

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11

Ibrahim, R. M. "Waste biomass densification for thermochemical conversion." Thesis, University College London (University of London), 2017. http://discovery.ucl.ac.uk/1563739/.

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Waste biomass densification into briquettes and pellets improves the characteristics of loose biomass residue for efficient transport, storage and thermochemical conversion into advanced fuels (e.g., syngas, for electricity, liquid fuels and chemicals). Briquettes of good and consistent quality are required but often difficult to achieve as more work is still required to understand how the chemical and physical properties of different biomass types, along with process variables, affect their quality. Also, the additional energy and cost associated with biomass briquetting has raised the issue of the sustainability of briquetting loose biomass before its conversion. This research focuses on the use of novel approaches to improve the quality of fuel briquettes for thermal applications, and further evaluates the sustainability of fuel briquetting, using life cycle assessment (LCA). Experiments were conducted to investigate the potential benefits of blending waste rice husks, corn cobs and bagasse, and with novel binders including enhanced treated biosolids, and microalgae (Chlorella sorokiniana), on fuel briquette properties, using factorial design methods. The new binders were also compared with existing starch binder. The range of briquettes produced in this study had unit densities of up to 3.3 times the loose biomass bulk density, and were stronger than briquettes from the individual biomass materials. Considering average values from two biomass sources, an unconfined compressive strength of 176 kPa was achieved at a compaction pressure of 31 MPa for a 3:7 blend of rice husks to corn cobs with 10% binder (starch + water). These briquettes were durable, with only 4% mass loss during abrasion, and 10% mass loss during shattering, tests. They absorbed 36% less water than loose corn cobs. An unconfined compressive strength of 175 kPa was also achieved for a 2:4:1 blend of rice husks, corn cobs and bagasse with 17% binder (microalgae), also at a compaction pressure of 31 MPa. The statistical analysis of the above results showed that the source of the biomass had a significant effect on densification, which emphasises the need to understand factors underlying biomass variability. Of all the briquettes produced with the three binders, those containing the microalgae binder were found to be most durable, with a higher energy density, slower mass loss during briquette combustion, and a higher afterglow time. Since microalgae may be grown using CO2 from biomass combustion, discovery of their advantages as a binder in briquetting is particularly welcome. To evaluate the sustainability of fuel briquetting, a detailed review of the existing LCA studies on fuel briquetting was carried out. These were found to provide insufficient and inconsistent information, due to different choices in system boundary, data sources, functional unit, allocation procedure, briquetting technology and biomass/briquette properties. An LCA model of biomass briquetting was therefore developed to enable transparent comparison of life cycle environmental impacts of briquetting with individual or blends of biomass feeds with a variety of technological options. The main model components include materials and process inventory databases derived from standard sources, main process calculations, user inputs and results sections. The model is open-access in a user accessible format (Microsoft Excel). A representative case study with mixed rice husks and corn cobs showed that the briquetting unit itself made the largest contribution, 42%, to the total life cycle operational energy of the briquetting system. For all the blends of rice husks and corn cobs explored in this study, the total life cycle energy of briquetting was in the range 0.2 to 0.3 MJ per MJ of fuel briquette energy content. Variation of the LCA input parameters in a sensitivity test for the same blend ratios, gave a range of total life cycle energy of briquetting from 0.2 to 1.7 MJ per MJ of fuel briquette energy content. This indicates that energy use in briquetting is not necessarily recovered, highlighting the need for continuous process optimisation and high quality LCA data. An increase in rice husks content of the blend increased the environmental impact of briquetting including the global warming potential (kg CO2-eq), acidification potential (kg SO2-eq), human toxicity (kg 1,4-DB-eq), ozone layer depletion (kg CFC-11-eq), and terrestrial ecotoxicity (kg 1,4-DB-eq) per MJ briquette energy content, as it was associated with a lower briquette density, which increased the energy required for handling.

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12

Бухкало, Светлана Ивановна, та Оксана Игоревна Ольховская. "Анализ возможностей комплексных технологий утилизации полимерной части твердых бытовых отходов". Thesis, Московский государственный университет дизайна и технологии, 2016. http://repository.kpi.kharkov.ua/handle/KhPI-Press/22983.

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Рассмотрены основные системы газификационных агрегатов большой единичной мощности. Выделены основные логистические факторы, влияющие на технологические схемы газификационных агрегатов такие, как природа, качество и состав газифицирующего сырья, номенклатура целевых продуктов, экологические требования по вредным выбросам и эмиссии парниковых газов, местоположение агрегата относительно крупных производственных комплексов, возможности конверсии отходов в полезные продукты.
The basic heat exchangers networks of big gasification plants with entrained-flow fuel gasification are considered. The main logistical factors that influence on process of gasification plants are underlined such fs nature quality and components content of fuel to be gasified, range of target products, environmental legislation and demands including greenhouse gases emission, location relatively to big industrial sites, possibilities of wastes conversion into saleable products.

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13

Omar, Abdulkadir Rahma, and Filippa Calmfors. "Food waste conversion : A study on how conversion can reduce in-store food waste in Swedish supermarkets." Thesis, Internationella Handelshögskolan, Högskolan i Jönköping, IHH, Centre of Logistics and Supply Chain Management (CeLS), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-43974.

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Problem: Food waste is a major issue from both an environmental as well as an economic perspective. In Europe alone, 90 million tons of food is wasted in the food supply chain every year. In order to reduce these excessive costs and the environmental impact, new food waste management strategies need to be developed and established. The food waste management strategies established in the retail stage are limited as the retail stage is an area of the food supply chain that has been neglected in research. Purpose: This thesis explores the food waste management of fresh fruits and vegetables out of retailer´s perspective. In specific, it assesses the potential effects for Swedish supermarkets in which have established processes where non-sellable products are recycled through conversion in-house. Method: This qualitative study has been performed through observational studies with semi-structured interviews to complement the observational findings. The empirical data is collected at Swedish supermarkets that have conversion processes established in their organization. The respondents were either store managers or managers for perishable goods. The data were analysed using the content analysis approach. Findings: The results of our research reveal that conversion activities of fresh fruits and vegetables result in less food waste and positive economic outcomes. To create higher economic value of the food waste conversion, the conversion of fresh fruits and vegetables should be performed in combination with other product categories.

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14

Lucian, Michela. "Hydrothermal Carbonization as an efficient route for organic waste conversion." Doctoral thesis, Università degli studi di Trento, 2020. http://hdl.handle.net/11572/264958.

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The production of municipal solid waste has continued to grow in recent years. In Italy, municipal solid waste production reaches about 29 million tons per year. The organic fraction of municipal solid waste (OFMSW), which accounts for 30-40% of the total waste, usually undergoes biological treatments such as anaerobic digestion or composting, or is incinerated or landfilled. Biological treatments are considered not economically viable due to the long processing time (20-30 days), while incineration and landfilling are considered as low cost but polluting processes. In contrast, Hydrothermal Carbonization (HTC) is a cost-effective process to treat organic waste especially for the shorter processing time (0.5-8 h) and the possibility to treat directly wet heterogeneous materials. This thesis aims to investigate the potential use of HTC to upgrade OFMSW and other biomasses to biofuels or valuable byproducts. Chapter 1 gives an overview on the state of the art of HTC technology applied to organic wastes, focusing both on mechanisms and on the characteristics of reaction products. Chapter 2 investigates the potential use of HTC to upgrade the organic fraction of municipal solid waste (OFMSW) into biofuel and byproducts. The impact of process conditions (process time, temperature and solid load) on the formation, chemical and energy properties of hydrochar was deeply investigated. To analyze the behavior of hydrochar as a solid biofuel, the combustion (oxidation) of hydrochar and the co-firing (co-oxidation) of hydrochars and coals was also investigated. The results show that, especially at HTC harsher conditions, hydrochar is a “coal-like” material, that can be used as a valuable solid biofuel. The results evidenced that hydrochar is composed of primary char and secondary char. Primary char (non-extractable with organic solvents) has characteristics similar to coal and could be recovered for combustion, while secondary char is an amorphous and more volatile solid, easily extracted with organic solvents, which found possible application as a source of biochemicals and liquid bio-fuel. Chapter 3 investigates the use of HTC as a promising pre-treatment to enhance the biomethane potential during anaerobic digestion of OFMSW. Anaerobic digestion experiments were carried out using the HTC process liquid and the entire HTC reaction mixtures. Results proved that, when compared to the raw OFMSW, the use of HTC liquid and HTC mixture into AD lead to an increase of biomethane production of up to 37% and 363% by volume, respectively. Chapter 4 reports an HTC kinetics study and a kinetic model, which accounted for reactions leading to the production of primary and secondary char, as well as the liquid and gas phases. The model was optimized using experimental data performed on a lignocellulosic feedstock (olive trimmings) and validated on two other types of biomasses (grape marc and Opuntia Ficus Indica) and was used as a reliable tool to predict the carbon distribution among HTC products. In this chapter an in-depth analysis was also carried out to understand the evolution of feedstock characteristics during the heat-up transient phase before reaching the HTC set-point temperature. The results show that during heat up, the feedstock carbonized to a considerable extent at 220-250 °C. Tests clearly show evidence of the transition between thermal hydrolysis and HTC. Chapter 5 presents a study conducted to evaluate the economic feasibility and the detailed energy and cost analyses of a hypothetical HTC plant transforming wet biomass into pelletized dry hydrochar. To achieve these goals, a model was developed on the basis of experimental results obtained previously on two other organic materials (grape marc and off-specification compost). The results show that, when operating the HTC plant with grape marc at the optimal HTC conditions (T=220 °C, t=1 h, dry biomass to water ratio=0.19), the production cost of hydrochar were determined to be 157 €/ton, competitive with the price of wood pellets (150-200 €/ton). This makes HTC a promising process for a large development at the industrial scale.

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15

Zheng, Sheng. "Biodiesel production from waste frying oil: Conversion monitoring and modeling." Thesis, University of Ottawa (Canada), 2003. http://hdl.handle.net/10393/26416.

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Biodiesel is a clean-burning substitute for petroleum-based diesel produced from virgin or waste vegetable oils and animal fats. One obstacle to the development of biodiesel is its high cost compared to petroleum diesel. Using waste frying oil instead of virgin oil can significantly reduce the high production cost. In our lab, promising preliminary results have indicated that transesterification of waste frying oil catalyzed by sulphuric acid has sufficient commercial feasibility to warrant further investigation. In order to better understand the acid-catalyzed transesterification process and to optimize the process yield, an empirical study of the reaction kinetics was carried out. A mixture design for feed compositions at various temperatures was used to determine their effects on conversion rates and yields. Empirical models were built to describe the relationships of interest. Rate of mixing, feed composition and temperature were chosen as independent factors in this study. Intensity of mixing was found to have no significant effect on the yield over 100 rpm. The methanol to oil ratio and temperature were the most significant factors affecting the yield. Finally, a region of optimum operating conditions was determined from the models. Analytical methods played an important role in our study. The extent of the reaction was followed off-line by gel permeation chromatography (GPC) and compared to results using an off-line infrared sensor based on attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy. The development, use and evaluation of the off-line method were discussed. The reproducibility of both methods was found to be excellent (≤1%); data obtained from both methods were found to be reliable. Finally, a comparison of the two methods showed good agreement (within 2%) in the monitoring of the transesterification reaction.

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16

Carlin, Nicholas Thomas. "Thermo-chemical conversion of dairy waste based biomass through direct firing." Texas A&M University, 2005. http://hdl.handle.net/1969.1/4844.

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Growing rates of manure produced from large dairies have increased concern for the environmental quality of nearby streams and watersheds. Typically the manure from the freestalls on these dairies is flushed with water to a mechanical separator. Here, flushed dairy biomass (DB) is parted into separated solids and separated liquid. The separated liquid is discharged into lagoons for treatment and eventual land application. This thesis proposes thermodynamic models for firing DB in small scale boiler systems that would eliminate land application and lagoons, which are being claimed to be the source of nutrient leaching and overloading. Fuel analysis of flushed DB from a dairy in central Texas show that it contains 93%moisture (%M), 3%ash (%A), and 4%combustibles (%Cb), while separated DB solids contain 81%M, 2%A, and 17%Cb. The dry, ash-free higher heating value of DB is approximately 20,000 kJ/kg. Using dry, ash-free results, computations can be made over ranges of %M and %A. For example, DB containing 70%M requires 9.74%Cb to vaporize all moisture and produce gaseous products of combustion at 373 K, but requires 17.82%Cb to burn in a regenerative combustor with a flame temperature of 1200 K. Separated solids that are pressed in an auger to 70%M (3%A and 27%Cb) can burn at 1200 K with exhaust temperatures of up to 1130 K and a minimum required heat exchanger effectiveness of 15%. Pressed solids can thus be fired in a boiler, where the remaining separated liquid can be used as feed water. The pressed solids only can release about 30% of the heat required to vaporize the remaining unclean feed water. However, pressed DB solids can be blended with drier fuels to vaporize almost all the unclean water. The low quality steam produced from the unclean water can be used in thermal processes on the farm. A similar system can be developed for vacuumed DB without the need to vaporize unclean feed water. As for large dairies with anaerobic digester systems already installed, directly firing the produced biogas in a small scale boiler system may be another way to similarly vaporize the remaining effluent.

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17

Pott, Robert William McClelland. "The bioconversion of waste glycerol into hydrogen by Rhodopseudomonas palustris." Thesis, University of Cambridge, 2014. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.708006.

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18

Dai, Siyang. "OPTIMIZED WTE CONVERSION OF MUNICIPAL SOLID WASTE IN SHANGHAI APPLYING THERMOCHEMICAL TECHNOLOGIES." Thesis, KTH, Industriell ekologi, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-187372.

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Thermochemical technologies have been proven effective in treating municipal solid waste (MSW) for many years. China, with a rapid increase of MSW, plans to implement more environmental friendly ways to treat MSW than landfill, which treats about 79 % of total MSW currently. The aim of this master thesis was to find out a suitable thermochemical technology to treat MSW in Shanghai, China. Several different thermochemical technologies are compared in this thesis and plasma gasification was selected for a case study in Shanghai. A model of the plasma gasification plant was created and analysed. Other processes in the plant including MSW pre-treating and gas cleaning are also proposed. By calculating the energy balance, it is demonstrated that plasma treatment of 1000 ton/day MSW with 70 % moisture reaches an efficiency of 33.5 % when producing electricity, which is higher than an incineration WtE plant (27 % maximum) and a gasification WtE plant (30 % maximum). Besides of the efficiency comparison, costs and environmental impacts of different technologies are also compared in this paper. The result indicated that given the characteristics and management situation of MSW in Shanghai, plasma gasification is a better choice to treat MSW in Shanghai.

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19

Lemonon, Jérôme. "Valorisations énergétique et matière du revêtement de sol stratifié par pyrolyse & gazéification." Thesis, Université de Lorraine, 2013. http://www.theses.fr/2013LORR0338/document.

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Depuis quelques temps, les enjeux énergétiques ne cessent d’apparaître en tête de liste des préoccupations actuelles pour l’avenir. La fin annoncée des énergies fossiles, à l’origine de 80% de celle que nous consommons aujourd’hui, s’accompagne naturellement par la recherche d’alternatives pour subvenir aux besoins futurs. L’intégration d’une dimension environnementale pour la mise en œuvre d’un développement durable met clairement en avant les atouts des énergies dites renouvelables qui concernent de nos jours moins de 15% de la production mondiale. Le travail proposé ici s’inscrit dans ce cadre de recherche et de proposition de sources d’énergies primaires renouvelables avec l’étude de valorisation de déchets contenant de la biomasse et plus particulièrement du cas du revêtement de sol stratifié. Parmi les diverses voies de valorisation actuelles, l’incinération avec l’ensemble des autres déchets reste le plus usité. L’inconvénient majeur réside dans la nécessité de traitement des fumées qui s’avère relativement coûteux. Il semblerait donc judicieux d’envisager une autre issue de valorisation. Le procédé proposé fait apparaître les trois étapes suivantes : une étape de prétraitement par pyrolyse à basse température (275°C) assurant une séparation des éléments azotés (précurseurs susceptibles de conduire à la formation de polluants) en altérant au minimum le matériau en vue d’une récupération maximale d’énergie lors de l’étape suivante ; une étape de valorisation énergétique, qui constitue le centre du procédé, par une pyrolyse à haute température (1000°C). L’énergie est obtenue par l’intermédiaire du gaz de synthèse ; et une étape de valorisation matière sous deux aspects avec l’obtention de produits à valeur ajoutée (panneaux de particules et charbons actifs) dont l’entrée dans le bilan économique global d’une installation industrielle pourrait s’avérer intéressante
Since a few years, energy challenges are appearing at the top of the list of the current concerns for the future. The forecasted end of fossil fuels, at the origin of 80% of currently consumed energy, is obviously accompanied by research about alternatives to provide for the future needs. The integration of an environmental care concerning the implementation of a sustainable development puts clearly ahead the assets of renewable energies which constitutes nowadays less than 15% of the worldwide production. Work suggested here deals with this scope of research and proposal for renewable primary energy sources with the recovery study of waste containing biomass and more precisely the case of laminated flooring. Among the various current recovering ways, incineration with the whole waste remains the most used one. The main drawback deals with the need for smoke treatment, the cost of which can be really high. It would thus seem to be judicious to look for another recovering issue. The suggested process is divided in the three following steps: - A pretreatment step through low temperature pyrolysis (275°C) making it possible a nitrogenous components separation of the elements (precursor able to form pollutants species) in deteriorating the fuel the less as possible to provide a maximum energy recovery in the following stage.- An energy recovery step, which constitutes the main goal of the process, through a high temperature pyrolysis (1000°C). Energy is recovered via syngas.- A material recovery step through two aspects in order to produce added-value material (particle boards and activated carbon), the consideration of which in the global economic assessment of an industrial installation could be interesting

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Sukhtankar, Samir A. "Thermochemical conversion of biomass into fuels and chemicals /." free to MU campus, to others for purchase, 2003. http://wwwlib.umi.com/cr/mo/fullcit?p1418068.

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21

Naqi, Ahmad. "Conversion of Biomass to Liquid Hydrocarbon Fuels via Anaerobic Digestion: A Feasibility Study." Scholar Commons, 2018. https://scholarcommons.usf.edu/etd/7639.

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The use of biomass as a potential feedstock for the production of liquid hydrocarbon fuels has been under investigation in the last few decades. This paper discusses a preliminary design and a feasibility study of producing liquid hydrocarbon fuels from biomass through a combined biochemical and thermochemical route. The process involves anaerobic digestion (AD) of the biodegradable portion of the biomass to produce methane rich gas. The methane rich biogas stream is purified by removing contaminants and upgraded to liquid hydrocarbon fuel in a gas to liquid facility (GTL) via thermochemical conversion route. The biogas conversion involves two major steps: tri-reforming step to produce syngas (a mixture of CO and H2), and Fischer-Tropsch Synthesis (FTS) step to convert the syngas to a spectrum of hydrocarbons. Separation and upgrading of the produced hydrocarbon mixture allows production of synthetic transportation fuels. AD is ranked as one of the best waste management options as it allows for: energy recovery, nutrient recovery, and reduction in greenhouse gases emission. A detailed process modeling of the process was carried out using ASPEN Plus process design software package. Data for the process was based on literature on AD combined with laboratory results on the biogas to liquid conversion process. The composition of the final liquid hydrocarbon from the ASPEN model has been compared to the composition of commercial diesel fuel, and results have shown good agreement. As a result, the most current commercial diesel prices were used to evaluate the potential revenue from selling the product in the open market. The total capital investment to construct the plant with a capacity of handling 100,000 ton per year of wet biomass is $16.2 million with a potential of producing 2.60 million gallons of diesel. The base case feedstock is corn stover. The annual operating cost to run the plant is estimated to be $8.81 million. An annual revenue from selling the diesel product is estimated to be $14.6 million taking into account a green energy incentive of $3.00/gallon of diesel sold. The net present worth at the end of the plant life is $8.76 million with a discounted cash flow of return of 26.2%. The breakeven cost of diesel is determined to be $4.34/gallon assuming no tipping fees are charged for handling the waste. Sensitivity analyses results concluded that the profitability of the process is most sensitive to variation in diesel selling price. Based on these results, it can be concluded that the process is profitable only if incentives are provided for renewable fuels due to the current low prices of fossil fuels.

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22

Myo, Min Win. "Thermochemical conversion characteristics of gas and tar generation from waste biomass and plastics." Kyoto University, 2020. http://hdl.handle.net/2433/253264.

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23

Balanco, Tannon Otto. "A continuous value proposition : waste created by food manufacturing companies and the conversion of bio-waste into biogas and fertiliser." Diss., University of Pretoria, 2015. http://hdl.handle.net/2263/52259.

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Sustainability has become a critical element in the way business strategies are designed. Many organisations have adopted best management practices and the corporate governance of modern companies have been aligned not only to look at profits but also to take into consideration the impacts that they have on people and on the planet. There has recently been a substantial acceptance towards renewable energy sources worldwide, however anaerobic digestion of bio-waste into bio-energy has been around for decades and has not seen the equivalent recognition in South Africa. The purpose of the research is to study the business considerations including challenges and opportunities emanating from the vast amounts of bio-waste that occurs throughout the food supply chain, specifically at manufacturing and is a high level assessment of the respective value propositions available as a strategic imperative within a sustainable business model. The research investigated the bio-waste emanating from food manufacturing which was conducted through the use of qualitative methods. In-depth interviews were held with ten experts from food manufacturing companies in which they shared their current bio-waste management practices. The triple bottom line model (Figure 2) was used as an initial framework, this model was reformulated into the sustainable business ecosystem (Figure 6) from which the interview schedule (Appendix 3) for the research questions was designed. Vast amounts of bio-waste occurs at the processing stage of the supply chain and to these ends a viable source of input material towards anaerobic digestion has been largely overlooked. There are research studies that have been conducted on biogas as well as the energy values of various substrates, however this research study was intended to investigate alternate revenue streams for an anaerobic digestion plant for the purposes of accelerating the return on investment of such a plant. A safe waste disposal fee has therefore been identified as a valuable value proposition that can be offered to food manufacturing plants. This bio-waste could then be utilised towards the generation of much needed electrical energy as opposed to the material going directly to landfill.
Mini-disseration (MBA)--University of Pretoria, 2015.
nk2016
Gordon Institute of Business Science (GIBS)
MBA
Unrestricted

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Nguyen, Thi Minh Nguyet, and Thi Thu Ha Chu. "Study on conversion of some chemical compounds of wood sawdust waste in biocomposting process." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2012. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-99302.

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This paper presents the research results of treatment solution of wood waste of Acacia and Eucalyptus in making of bioorganic fertilizers for the effective utilization of plant biomass resources and minimization of environmental pollution. The conversion cycles of the basic chemical compounds of wood waste in composting process were established by two biological products: Biomix and Compost Maker. Research results have shown that, under the action of microorganisms, all basic chemical compounds were modified (among them cellulose was most powerfully modified) whereas lignin, extractives dissolved in ethanol were less destructed. Within about first 75 days of composting, the conversion of the above mentioned compounds is negligible. With the time of composting from 105 days to 120 days, in total over of 70% of cellulose was conversed into compounds dissolved in water and in 1% NaOH solution. The optimal composting time was about 105 days. In this case, the fertilizer obtained was humified, had dark colour and could be used for planting and soil improvement purposes
Bài báo này trình bày các kết quả nghiên cứu giải pháp xử lý mùn vụn gỗ phế thải của gỗ Keo và Bạch đàn thành phân bón hữu cơ vi sinh, nhằm tận dụng hiệu quả nguồn sinh khối thực vật và giảm thiểu ô nhiễm môi trường. Đã xác lập được một số quy luật biến đổi của các thành phần hóa học cơ bản của mùn vụn gỗ trong quá trình ủ compost bằng hai chế phẩm vi sinh Biomix và Compost Maker, để tạo phân bón hữu cơ vi sinh. Kết quả nghiên cứu đã cho thấy, dưới tác dụng của vi sinh vật, tất cả các thành phần hóa học cơ bản của mùn vụn gỗ đều bị biến đổi, trong đó xenluloza bị biến đổi mạnh nhất, lignin và các chất trích ly bằng etanol ít bị phân hủy hơn. Trong vòng khoảng 75 ngày ủ đầu tiên, sự biến đổi của các thành phần nêu trên là không đáng kể. Với thời gian ủ từ 105 ngày đến 120 ngày, tổng cộng có trên 70% xenluloza bị phân hủy thành các hợp chất dễ tan trong nước và dung dịch NaOH 1%. Thời gian ủ thích hợp là khoảng 105 ngày. Trong trường hợp này, phân bón thu được đã bị mùn hóa, có mầu sẫm và có thể sử dụng cho mục đích trồng trọt và cải tạo đất

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Fernandes, Teresa. "Geochemical behaviour of uranium and thorium in the waste of a uranium conversion facility." Doctoral thesis, Universitat Autònoma de Barcelona, 2017. http://hdl.handle.net/10803/460838.

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Los residuos contenidos en las balsas de decantación de la planta de conversión de uranio de Comurhex - Malvési, Francia, han sido caracterizados con el objectivo de investigar el comportamiento de uranio y torio en este entorno específico. El residuo es una sucesión de estratos heterogénea que comprende una mezcla de los efluentes del proceso con el suelo (que han tenido su origen en la re-construcción de los diques de las balsas, el efluente de lodo, y los antiguos desechos de las minas de azufre y de flotación de residuos sobre las que las balsas han sido localizadas. El efluente de lodo original tiene una composición química heterogénea que varía espacialmente y con la profundidad en las balsas debido a la evolución del proceso de conversión con el tiempo y debido a la materia prima recibida de diferentes minas del mundo. En esta tesis, se combinó un examen detallado de los desechos y del agua intersticial, experimentos de batch y en columna, y el modelado geoquímico para caracterizar la composición del material y determinar la especiación geoquímica del uranio y el torio. Los datos presentados en esta tesis han elucidado los mecanismos geoquímicos que controlan la migración de estos elementos y cómo esta migración puede verse afectada en el largo plazo. El uranio en el estrato de los lodos está presente en más de una especiación: como una fase de silicato, como una fase de óxido de uranilo, adsorbido en oxihidróxidos de hierro y asociados a los principales minerales, tales como yeso y calcita. Uranio en los otros estratos de residuos está presente en concentraciones más bajas que las cuantificables mediante técnicas espectroscópicas. La liberación de U (VI) y su transporte dentro de los estratos oxidantes de los lodos está dominado por disolución limitada cinéticamente - y transformación de uranofana, o una fase similar de uranilo - silicato. Las concentraciones de uranio acuoso bajo condiciones experimentales son controladas por una fase mineral. La fase mineral limitante de solubilidad más común en condiciones experimentales ha sido la schoepita (deshidratada). Sin embargo, a escala de campo, y debido a la naturaleza heterogénea de los residuos en las balsas, es posible que, a nivel local, otras fases de uranio pueden ser los principales minerales de solubilidad control. El torio se distribuye homogéneamente en los resíduos, y se encuentra, ocasionalmente correlacionado con el uranio como óxido de U-Th. Las concentraciones de torio en solución son controladas por ThO2. Este trabajo ha puesto en evidencia la importancia de un enfoque que comprenda técnicas complementarias en la caracterización de la especiación sólida de uranio y torio en un material heterogéneo.
The waste contained in the decantation basins of the uranium conversion plant of Comurhex-Malvési, France, was characterised to investigate the behaviour of uranium and thorium in this specific environment. The waste is a succession of heterogeneous strata comprising a mixture of the process effluent with soil (arising from the reconstruction of the basins’ dykes), the sludge effluent, and the former sulphur mine tailings and flotation waste over which the basins have been sited. The original sludge effluent has a heterogeneous chemical composition that varies spatially and with depth in the basins due to the evolution of the conversion process over time and due to the different raw material received from mines around the world. In this thesis, a detailed examination of waste cores and pore waters, static batch and kinetic column test work, and geochemical modelling was combined to characterise the composition of the material and the geochemical speciation of uranium and thorium. The data reported in this thesis have elucidated the geochemical mechanisms that control the migration of these elements and how this migration can be affected in the long term. Uranium in the stratum of sludge is present under more than one speciation: as a silicate phase, as a uranyl-oxide phase, adsorbed to iron oxy-hydroxides and associated with major minerals, such as gypsum and calcite. Uranium in the other strata of waste is present at concentrations that were not quantifiable by spectroscopic techniques. The release of U(VI) and its transport within the oxidising strata of sludge is dominated by kinetically-limited dissolution and transformation of uranophane, or a similar uranylsilicate phase. Aqueous uranium concentrations under experimental conditions are controlled by a mineral phase. schoepite (dehydrated) was found to be the most common solubility limiting mineral. However, at the field scale, and due to the heterogeneous nature of the waste in the basins, it is possible that, locally, other uranium phases may be the main solubility controlling minerals. Thorium is homogeneously distributed in the sludge, and occasionally correlated with uranium, as a U-Th oxide. Thorium concentrations in solution are controlled by ThO2. This work has put in evidence the importance of an approach comprising complementary techniques in the characterisation of the solid speciation of uranium and thorium in a heterogeneous material. The use of multiple techniques is required to identify different phases and in order to establish multiple lines of evidence for the presence of a certain physical form.

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DiGenova, Kevin (Kevin J. ). "Design of organic Rankine cycles for conversion of waste heat in a polygeneration plant." Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/68937.

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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2011.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 124-126).
Organic Rankine cycles provide an alternative to traditional steam Rankine cycles for the conversion of low grade heat sources, where steam cycles are known to be less efficient and more expensive. This work examines organic Rankine cycles for use in a polygeneration plant that converts coal feedstock into hydrocarbon products and electricity. Since a Fischer Tropsch reactor is the largest source of low grade heat in the polygeneration plant, rejecting heat at a constant temperature of 240°C, the analysis in this work focuses on utilizing the waste heat from this process. Organic Rankine cycles (ORC's) are modeled in MATLAB using pure substance data available from Refprop 8.0. Various working fluids are considered, with a particular focus on hexane, heptane, octane, nonane, and decane. Hexane is the best option for the Fischer Tropsch heat source and the working fluids considered here. A set of ORC design concepts (building blocks) is developed to allow a cycle to be matched to a generic heat source, and is demonstrated using the Fischer Tropsch heat source profile. The low pressure steam Rankine cycle achieves a 20.6% conversion, while a baseline hexane organic Rankine cycle achieves a 26.2% conversion efficiency for the same Fischer Tropsch heat source. If the ORC building blocks are combined into a cycle targeted to match the temperature-enthalpy profile of the heat source, this customized hexane cycle achieves 28.5% conversion efficiency. For a polygeneration plant with a 25,000 ton per day input of coal, the conversion efficiency is improved by 0.3 to 0.5 points. Moreover, by combining the ORC building blocks identified in this work into new configurations, cycle designers can create customized organic Rankine cycles that target any heat source temperature-enthalpy profile to achieve improved conversion efficiencies.
by Kevin J. DiGenova.
S.M.

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27

Donaj, Pawel. "Conversion of biomass and waste using highly preheated agents for materials and energy recovery." Doctoral thesis, KTH, Energi- och ugnsteknik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-34253.

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One of the greatest challenges of human today is to provide the continuous and sustainable energy supply to the worldwide society. This shall be done while minimizing all the negative consequences of the operation(s) to the environment and its living habitants including human beings, taking from the whole life cycle perspective. In this thesis work new solutions for treatment biomass and waste are analyzed. Based on the fundamental research on the conversion of various materials (biomass: straw pellets, wood pellets; and waste: plastic waste, ASR residues after pyrolysis), converted by means of different systems (pyrolysis in a fluidized bed reactor, gasification in a fixed-bed reactor using highly preheated agents) it is recommended to classify materials against their charring properties under pyrolysis, in order to find the best destination for a given type of fuel. Based on phenomenological research it was found that one of the important effects, affecting performance of downdraft gasifiers, is the pressure drop through the bed and grate. It affects, directly, the velocity profile, temperature distribution and of the height of the bed, especially for the grate with restricted passage surface, although it was not investigated in literature. The lower grate porosity, the higher conversion of fuel and heating value of gas is produced. However, the stability of the process is disturbed; therefore reducing the grate porosity below 20% is not recommended, unless the system is designed to overtake the consequences of the rising pressure inside the reactor. This work proposed the method for prediction of a total pressure drop through the fixed-bed downdraft gasifier equipped with a grate of certain porosity with an uncertainty of prediction ±7.10. Three systems have been proposed; one for the treatment of automotive shredder residue (ASR), one for the treatment of plastic waste (polyolefins) and one for biomass (wood/straw pellets). Pyrolysis is an attractive mean of conversion of non-charring materials (like plastic waste) into valuable hydrocarbons feedstock. It gives directly 15-30% gaseous olefins while the residue consisting of naphtha-like feedstock has to be reformed/upgraded to olefins or other chemicals (e.g. gasoline generation) using available petrochemical technologies. Pyrolysis of complex waste mixture such as ASR is an attractive waste pretreatment method before applying any further treatments, whereby useful products are generated (gaseous and liquid fuel) and char, rich in precious metals. The solid residues are meant for further treatment for energy and metals recovery. Gasification is a complementary method for handling pyrolysis residues. However, metals can be removed before gasification. Pyrolysis of charring materials, like biomass, is a very important step in thermo-chemical conversion. However, the char being approximately 25%wt. contains still very high caloric value of about 30MJ/kg. This in connection with the High Temperature Steam Gasification process is a very promising technology for biomass treatment, especially, above 900oC. This enhances the heat transfer towards the sample and accelerates kinetics of the gasification. This, in turn, improves the conversion of carbon to gas, increases the yield of the producer gas and reduces tar content. At higher steam to fuel ratio the process increases the yield of hydrogen, making it suitable for second-generation biofuels synthesis, whereas at lower steam to fuel ratio (S/F<2) the generated gas is of high calorific value making it suitable for power generation in a combined cycle.

QC 20110607

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28

Nyamhingura, Amon. "Characterization and chemical speciation modelling of saline effluents at Sasol Synthetic Fuels Complex-Secunda and Tukuta power station." Thesis, University of the Western Cape, 2009. http://etd.uwc.ac.za/index.php?module=etd&action=viewtitle&id=gen8Srv25Nme4_7974_1297940655.

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The study shows conclusively that brine composition and concentration is highly variable at these South African power utilities and processes such as RO, contact with ash and CO2 ingress can have an impact upon the overall brine quality. Aq.QA was found to be a more accurate tool for classifying waters according to dominant ions than Stiff diagrams but Stiff diagrams still have the superior advantage of being a mapping tool to easily identify samples of similar composition as well as quickly identify what has been added or what has been removed from a water stream. Chemical speciation could identify effluent streams where CO2 dissolution had taken place.

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ALY, OMAR F. "Estudo para conversao de partes poluentes dos gases de combustao de termoeletrica a oleo em materia prima para fertilizante." reponame:Repositório Institucional do IPEN, 2001. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10869.

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Made available in DSpace on 2014-10-09T12:44:55Z (GMT). No. of bitstreams: 0
Made available in DSpace on 2014-10-09T13:59:48Z (GMT). No. of bitstreams: 1 07173.pdf: 11277724 bytes, checksum: 5b5dfb2b888fca36e76b5cf99fdb18ab (MD5)
Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares, Sao Paulo

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30

Zhou, Chunguang. "Gasification and Pyrolysis Characterization and Heat Transfer Phenomena During Thermal Conversion of Municipal Solid Waste." Doctoral thesis, KTH, Energi- och ugnsteknik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-154587.

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The significant generation of municipal solid waste (MSW) has become a controversial global issue. Pyrolysis and gasification technologies for treating rejects from solid waste disposal sites (SWDSs), for which over 50 % of MSW is attributed to combustible species, have attracted considerable attention. MSW is an alternative energy source that can partly replace fossil resources; there is an increasing awareness that global warming caused by the utilization of fossil resources is occurring. The goal of this thesis is to realize the efficient and rational utilization of MSW and decrease the harmful impact of pollutants, such as dioxin, HCl, and CO2, on the environment. To achieve this goal, some fundamental studies have been experimentally and numerically conducted to enhance the understanding of the properties of municipal solid waste thermal conversion. In this thesis, the pyrolysis behaviors of single pelletized recovered fuel were tested. A detailed comparison of the pyrolysis behaviors of typical recovered solid waste and biomass particles was conducted. A swelling phenomenon with a swelling ratio of approximately 1.6 was observed on the surface of pelletized recovered fuels. Subsequently, a particle model was constructed to describe the thermal conversion process for large recovered fuel particles that are composed of a high fraction of polyethylene (PE) and a comparable low fraction of cardboard. The results indicate that an understanding of the heat transfer mechanism in highly porous and molten structures and the selection of a heat transfer model are crucial for accurate prediction of the conversion process. MSW pyrolysis is a promising method for producing liquid products. With the exception of lignocellulosic materials, such as printing paper and cardboard, PE, polystyrene (PS), polypropylene (PP), polyethylene terephthalate (PET), and polyvinyl chloride (PVC) are the six main polymers in domestic waste in Europe. Characterization studies of the products obtained from these individual components, such as PE, PET, PVC, printing paper, and cardboard, have been conducted on a pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) system and a fixed-bed reactor. The possible pathways for the formation of the main primary/secondary products in rapid and conventional pyrolysis were also discussed. MSW steam gasification with CaO was performed in a batch-type fixed-bed gasifier to examine the effect of CaO addition on the heat transfer properties, pollutant removal, and devolatilization and char gasification behaviors in the presence of steam. A new carbon capture and recycle (CCR) system combined with an integrated municipal solid waste system was proposed. The foundation of the system is the development of a novel method to remediate CO2 using a high-temperature process of reforming CH4 and/or O2 and/or H2O without catalysts. Thermodynamic and experimental studies were performed. High temperatures significantly promoted the multi-reforming process while preventing the problem of catalyst deactivation. Potential improvements in the efficiency of the novel technology can be achieved by optimizing the reforming reactants. Landfill gas (LFG) and fuel gas from bio-waste treatment contain a considerable fraction of CH4, which may be a source of CH4 for this process.

QC20141028

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31

Serage, Noah Magonagone. "Plasma gasification for converting municipal solid waste to energy." Thesis, Nelson Mandela Metropolitan University, 2017. http://hdl.handle.net/10948/20266.

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In South Africa most of the municipal solid waste is currently removed and taken to land fill sites for engraving. A very small percentage of this is recycled due to lack of exploration of alternative means of further processing. In 2011 approximately 108 million tonnes of waste, mostly being general waste was generated in South Africa. Ninety eight (98) million tonnes of this waste was disposed of at landfill sites (The Department of Environmental Affairs [DEA], 2012). Environmental engineers are finding municipal solid waste management to be a challenge, similarly do the city planners and local administration. The main reason being the difficulty brought about by the complexity in composition of the waste material, no availability of waste minimization technologies and the scarcity of land for landfill sites and their environmental impact (Lal & Singh, 2012). Anyaegbunam (2013) recommend that there is a disposal technique that can convert most of the landfill waste at reduced amount of money to what is being paid on other disposal techniques nowadays, regardless of its form or composition and produce an excess of clean energy, and that technique is called Plasma Gasification which carries a high capability of being economically efficient. According to Young (2010), plasma arc Gasification is a high-temperature pyrolysis process whereby the organics of waste solids (carbon-based materials) are converted into syngas. The syngas can also be sent to gas turbines or reciprocating engines to produce electricity. Few of these plants exist in the world, however there is none in South Africa due to municipal budgetary constraints and lack of evidence for return on investment. Gasification can be described as a thermo-chemical process wherein carbonaceous or carbon-rich feed stocks, for instance tree trimmings or biomass, coal, and petro-coke are transformed into a complex gas containing hydrogen and carbon monoxide (and smaller quantities of carbon dioxide and other trace gases) under high pressure, oxygen exhausted, strong heat and/or steam environments (SRS Energy Solutions, 2016) The problem of electricity shortages continues to increase and communities are unable to cope with the continuous rising electricity bills. It is forecast that electricity demand will grow by approximately 85% and thereby reaching 31 700TWH (terawatt hours) in the year 2035. This growth rate is anticipated at an annual rate of 2.4% of which the economic and population growth will be the driving force, while on the other hand the daily increase of waste at landfill sites poses many problems with regards to the lifespan of the landfill in case green technological disposal processes are not introduced.

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32

Cho, João Daniel. "Modelagem termodinâmica do processo de gaseificação : modelos de equilíbrio e semi-equilíbrio." reponame:Repositório Institucional da UFABC, 2017.

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Orientador: Prof. Dr. Antonio Garrido Gallego
Dissertação (mestrado) - Universidade Federal do ABC. Programa de Pós-Graduação em Energia, 2017.
A gaseificação é o processo de conversão termoquímica de um combustível sólido em um gasoso, produzindo o chamado gás de síntese a partir da sua combustão incompleta. O caráter energético do gás de síntese provém das parcelas metano (CH4), monóxido de carbono (CO), hidrogênio (H2) presentes, permitindo assim a utilização de resíduos sólidos para produção de um gás combustível, possibilitando sua melhor valoração em energia (waste-to-energy) com a sua utilização em ciclos de potência mais eficientes a partir de ciclos combinados e ganhos ambientais com esta conversão. Também há sua valoração para síntese de outros produtos químicos (waste-to-products) com maior valor agregado. Este trabalho tem como objetivo o estudo do processo de gaseificação, culminando na criação de modelos termodinâmicos para a descrição e predição deste fenômeno. Para isso foi realizada uma revisão bibliográfica, na qual foi feito um levantamento dos principais mecanismos descritivos do processo, principais aspectos relevantes de influência, parâmetros de análise e configurações dos principais gaseificadores utilizados atualmente. Também foram avaliados os modelos utilizados na literatura para descrição do processo, que dentre os quais escolheu-se metodologias baseadas na condição de equilíbrio químico para este trabalho. Estas metodologias utilizaram o chamado modelo estequiométrico e não-estequiométrico que se baseiam na condição supracitada. Foram identificadas deficiências quanto a previsão do gás de síntese resultante dos modelos propostos quando comparadas a dados experimentais levantados na literatura. Estas derivam principalmente da não representação de alguns fatores cinéticos, principalmente no tocante ao fenômeno de decomposição térmica no processo de gaseificação. Para contornar estas limitações, a introdução de correlações externas se mostra uma ferramenta comumente utilizada na bibliografia. Assim, foi analisada a inclusão de correlações para a previsão das parcelas de CO2, H2 e CH4, e uma função para a previsão de carbono não convertido (coque). Esta última se mostrou fundamental para uma melhor acurácia da previsão do poder calorífico do gás de síntese pelos modelos propostos.
Gasification is a thermochemical conversion process of a solid combustible into gaseous phase, producing a so-called syngas from an incomplete combustion. The energetic value of syngas is due to fractions of methane (CH4), carbon monoxide (CO) and hydrogen (H2), which enable the utilization of solid residues to produce a combustible gas (waste-to-energy). Gasification provides a better energetic valuation with its utilization on more efficient power cycles through combined cycles and environmental gains due to the conversion process. In addition, it is possible to usage utilize syngas to produce other chemical compounds (waste-to-products) with a higher commercial value. This thesis main objective is to study the gasification process, where it is proposed mathematical models to describe and predicts this phenomenon. It is conducted a bibliographical review, of which includes the descriptive mechanism and main analysis influential parameters related to this process, where commonly utilized configurations gasifier is also explored. It was also analyzed the main models observed on the literature to describe the gasification process, of which was selected methodologies based on the chemical equilibrium for this work. These methodologies utilized the stoichiometric and non-stoichiometric models that were based on the previously mentioned condition. Deficiencies related to predicted values of the composition fractions of the syngas are observed when compared to experimental data from the literature. These derive mainly from the non-representation of kinetic factors, primarily due to the pyrolysis stage of the gasification process. The usage of external correlations are useful tools to smooth these deficiencies. Therefore, an analysis of the inclusion of correlations to predict gaseous fractions of CO2, H2 and CH4 of the syngas and the fraction of non-converted carbon (char) was made. The latter proposal has shown essential to a better accuracy of the modelled calorific value of syngas.

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33

O'Brien, Megan Lynn. "Design of a mobile torrefaction reactor for in-situ conversion of agricultural waste to solid biofuel." Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/104263.

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Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 143-149).
Significant volumes of biomass waste are generated each year as a result of agricultural practices in India. Despite the negative environmental impacts, in-situ incineration of crop residues is common practice for disposal of this waste. Transportation of raw biomass accounts for a significant portion of the cost of biomass conversion processes due to its low energy density and high bulk volume. The use of raw biomass also reduces the overall efficiency of thermochemical conversion processes due to high moisture content, over-oxidation of the fuel resulting from high oxygen content, and the relatively high oxygen to carbon ratio. There has been much recent interest in improving the properties of biomass prior to gasification and pyrolysis through densification, drying, and mild thermochemical treatments. One approach is a process known as torrefaction, which is a mild pyrolysis process that is shown to produce an energy-dense fuel with improved transport, storage, and feedstock characteristics. Particularly in the Indian context, there is a need for the development of a small-scale system which can densify and upgrade the properties of agricultural residues after harvest. This thesis presents the design and preliminary testing of a lab-scale moving-bed torrefaction reactor. Key learnings from the assembly and testing of this machine are identified and recommendations for improvement are made. A rudimentary model evaluating the heat transfer in packed bed of biomass is developed to provide a framework for analyzing future reactor designs. The functional requirements of a labscale screw conveyor torrefaction reactor are developed based on this analysis and a preliminary reactor architecture is proposed. Multiple studies are recommended to improve the reliability of the heat transfer model. Recommendations are made for future design iterations of the lab-scale screw conveyor torrefaction reactor.
by Megan Lynn O'Brien.
S.M.

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34

Hlaba, Aviwe. "Process optimization and environmental assessment of municipal solid waste conversion to liquid fuels and/or chemicals." Thesis, Cape Peninsula University of Technology, 2020. http://hdl.handle.net/20.500.11838/3047.

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Thesis (MEng (Chemical Engineering))--Cape Peninsula University of Technology, 2020
South Africa currently faces an energy security issue with regards to the country’s rather insignificant petroleum reserves. The Fischer-Tropsch Synthesis process has found great application in converting the reserves available to products of economic value in terms of fuels and chemicals finding the adequate application at Sasol and Petro SA alike. However, in the realisation of the fact that coal is a high pollutant and natural gas reserves at a critical low with Sasol and Petro SA respectively, new innovations have become of critical importance. Solid waste management has become an ever-growing problem world-wide due to rapid urbanization and population growth. South Africa was found to have generated 9 million tons of general waste in 2011 with the Western Cape generating 675 kg/capita/annum. The convention of management has been that of landfilling however, this method is fast becoming insignificant due to the lack of space and detrimental nature to the environment. Considering the energy security issue South Africa is facing, and the global drive of finding alternate sources of fuel with the depletion of fossil fuel, attention has turned to MSW as a sustainable source of energy while remediating its effect on the environment. Thermochemical conversions of Municipal Solid Waste (MSW), this presents an attractive means of harnessing the potential value in this waste stream thus thermochemical conversion poses an attractive means of converting this waste stream into valuable fuel products. In the realisation of the 2 problems of energy security and solid waste disposal, Biomass to Liquid (BTL) technology was found to be the most suitable to tackle these issues. BTL is an established process that uses the thermal conversion of biomass into various liquid fuels products through a series of technologies. MSW is highly heterogeneous which poses a processing challenge, unlike virgin biomass which is normally used in BTL technologies. The study investigated the production of high-quality syngas through an Aspen simulation of thermal gasification which would be suitable for liquid fuels and chemicals via Fischer-Tropsch synthesis to bridge the energy security issue in South Africa. As the study also possesses an environmental facet, it was necessary to assess the pollution load caused by the process of landfilling in terms of Heavy Metals and Radionuclides which will be determined by means of radionuclide analysis and heavy metal analysis. The procedures were accomplished by use of the gamma-ray spectroscopy, High Purity Germanium detector, (HPGe) and Inductively Coupled Plasma Optical Emission Spectrometry, (ICP-OES) methods. The study was conducted by making use of Refuse Derived Fuel (RDF) pellets produced from the MSW. 4 Different binders in form of corn starch, guar-gum starch, waste palm oil and waste engine oil were used in the production of the pellets, thus the effect of this on energy content and thermal degradation behaviour was studied. The energy content of MSW in Cape Town was investigated using a bomb calorimeter and the thermal degradation behaviour was studied using Thermogravimetric Analysis (TGA). The South African Government, through the National Development Plan of South Africa, aims to provide access to the grid and off-grid electrical power to a minimum of 95 % of the population by 2030, of which 20 GW of the required 29 GW required for this needs to come from alternative and renewable energy sources. This study using the MSW from the City of Cape Town Municipality in South Africa shows that the MSW has a calorific value of approximately 19 MJ/kg which is significantly high, meaning that the waste can be directly used as fuel in many applications but more importantly that of electricity generation. The calorific value for the pelletised waste was found to be higher at an average of 23.9 MJ/kg which can be compared with South African coal being 25.1 MJ/kg. Using TGA, 3 distinguishable major mass loss regions were found between temperatures 55 – 265 ℃, 270 – 410 ℃ and 410 – 502 ℃. The total sample reduction was found to be more than 90 % on average which is a reduction of the waste. Heavy metals and Radionuclides (HM and R) are abundant in various types of municipal solid waste, including industrial waste, construction waste, medical waste, and household waste. Products containing HM and R are commonly disposed of in MSW or hazardous waste landfills and dumpsites. Approximately an average of 0.8 to 3 kg per capita per day of MSW is generated by suburban areas in South Africa. This method of managing or processing the waste has fast become inadequate and hence the need for new innovations. This has led to the focus on thermochemical conversion as an alternative. The soil is amongst the most considerable sources of radiation exposure to human beings and the migration for the transfer of radionuclides to the immediate environment. Exposure is a direct result of gamma-ray emissions that are produced by the most common terrestrial radionuclides, which are the member of the 238U and 232Th series and 40K of which concentrations differ with respect to the type of soil and the geology of the area. Environmental pollution by chemicals and heavy metals such as Cd, Ni, Zn, and Pb etc., showed a great increase in recent times due to various industrial operations including that of MSW disposal. All heavy metals at high concentrations have strong toxic effects and are regarded as environmental pollutants. Naturally occurring radionuclides activity was investigated at landfill sites from the City of Cape Town using a Hyper-Pure Germanium (HPGe) detector with appropriate shielding coupled to a Palmtop Multichannel Analyzer. Activity concentrations of the radionuclides 238U, 232Th and 40K were obtained from the activity concentrations of their respective daughter radionuclides. To obtain the overall combined effect in terms of activity concentration from the 3 parent radionuclides, the radium equivalent was calculated and 38.273, 41.019 and 83.007 Bq/Kg were obtained from Bellville, Coastal Park, and Vissershok respectively. Other radiological hazards in terms of Internal and External hazard indices and Representative hazard index were determined and found to be within safe limits. The dose rate in the air at 1m above the ground was determined to obtain a characteristic of the external gamma-ray and was found to be 17.490, 18.609 and 38.667 nGy/y for Bellville, Coastal Park, and Vissershok respectively. The health effects of the radiation in terms of annual effective dose and excess lifetime cancer risk were determined to be 0.031 mSv/y and 0.0961×10-3 which are lower than limits set by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) and the Nuclear Industry Association of South Africa (NIASA). The gasification part of the study was through process simulation models on ASPEN Plus Process simulation software. This investigation proposes a model of syngas creation from Refuse Derived Fuel (RDF) Pellet gasification with air in a fixed bed reactor. The model (utilizing Aspen Plus process simulation software) is utilized to model the anticipated results of RDF gasification and to give some processes fundamentals concerning syngas generation from RDF gasification. The fixed bed reactors are an updraft fixed bed reactor which can be divided into 3 sections which are drying, pyrolysis and gasification. The model is based on a combination of models that the Aspen Plus simulator provides, representing the three stages of gasification. Thermodynamics package used in the simulation comprised the Non-Random Two-Liquid (NRTL) model. The model works on the principle of Gibbs free energy minimization and was validated with experimental data of MSW gasification found in the literature. The RYield module was combined with the RGibbs module to describe pyrolysis section, while the RGibbs module was used for the gasification section individually. Proximate and ultimate analysis of RDF pellets and operating conditions used in the model are discussed. The sensitivity analysis module of Aspen Plus was used to research the effect of air equivalence ratio, ER and temperature value on the syngas composition, and carbon conversion. The results indicate that higher temperature improves gasification as the composition of H2 and CO increase, as well as carbon conversion until a temperature of 900 ℃ and higher air equivalence ratio increases the carbon conversion while decreasing syngas quality as there is an increase in CO2 and H2. The most suitable binder for the gasification of RDF derived from MSW is maize starch, with the optimal process parameters for the production of syngas being that of temperature at 780 0C and airflow rate of 6 kg/hr which translates into a fuel-to-air feed ratio of about 1:2. Results obtained are in good agreement with the experimentally measured data in the literature.

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35

Fedotov, Alexey. "Conversion of methane and carbon dioxide on porous catalytic membranes." Thesis, Vandoeuvre-les-Nancy, INPL, 2009. http://www.theses.fr/2009INPL099N/document.

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L’étude concerne un nouveau procédé de reformage du gaz naturel en gaz de synthèse par le dioxyde de carbone (RSM), en vue de l'utilisation rationnelle des déchets carbonés industriels pour la production d'hydrocarbures et d'hydrogène. Cette méthode utilise des systèmes à membranes catalytiques inorganiques (SMC) qui favorisent des réactions catalytiques hétérogènes en phase gazeuse dans des micro-canaux céramiques. La surface active des catalyseurs formés à l'intérieur des canaux est faible en termes de superficie, mais elle est caractérisée par une valeur élevée du facteur Surface/Volume du catalyseur, qui induit une efficacité importante de la catalyse hétérogène. Les SMC, formés à partir de dérivés alcoxy et des précurseurs métalliques complexes, contiennent de 0,008 à 0,055% en masse de nano-composants mono- et bimétalliques actifs répartis uniformément dans les canaux. Pour les systèmes [La-Ce]-MgO-Ti02/Ni-Al et Pd-Mn-Ti02/Ni-Al, les productivités de 10500 et 7500 1/h·dm3membr. ont été respectivement obtenues lors du RSM dès 450°C avec une composition de gaz de synthèse H2/?? allant de 0,63 à 1,25 et un taux de conversion de 50% de la charge CH4/CO2 (1/1). Ainsi les SMC sont d’un ordre de grandeur plus efficace qu’un réacteur à lit fixe du même catalyseur. Le RSM est initié par l'oxydation de CH4 par l'oxygène de structure des oxydes métalliques présents en surface, et le CO2 réagit avec le carbone finement divisé provenant de la dissociation de CH4. Une synergie catalytique a été mise en évidence pour le système Pd-Mn. Ces SMC de 108 pores par cm² de surface constituent un ensemble de nano réacteurs de fort potentiel industriel (synthèse d’oléfines, biomasse)
This study reports the development of a new process to convert methane and carbon dioxide (dry methane reforming - DMR) into valuable products such as syngas from non-oil resources. The practical interest is to produce syngas from carbon containing exhaust industrial gases. This process uses membrane catalytic systems (MCS) that support heterogeneous catalytic reactions in gaseous phase in ceramic micro-channels. The active surface of the catalysts formed inside the micro-channels is low in term of area, but it is characterized by a high value of the catalyst surface/volume ratio, which induces a high efficiency of heterogeneous catalysis. The SMC are formed from alkoxy derivatives and precursor metal complex containing between 0.008 and 0.055% by weight of nano-components mono-and bimetallic active distributed evenly in the channels. For systems [La-Ce] -MgO-Ti02/Ni-Al and Pd-Mn-Ti02/Ni-Al, productivities of 10500 and 7500 l/h · dm3 membr. were respectively obtained by RSM at 450°C with a composition of syngas H2/?? ranging from 0.63 to 1.25 and a conversion rate of 50% with a CH4/CO2 (1/1) feed. Thus the CMS is an order of magnitude more efficient than a fixed bed reactor of the same catalyst. The MDR is initiated by the oxidation of CH4 by structural oxygen of metal oxides available on the surface, and the CO2 reacts with the finely divided carbon arising from the dissociation of CH4. A catalytic synergy has been demonstrated for the system Pd-Mn. This CMS, having 108 pores per cm² of surface, can be considered as a set of nano reactors. Thus this new approach is very promising for industry (synthesis of olefins, uses of biomass)

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36

Kent, Ryan Alexander. "Conversion of Landfill Gas to Liquid Hydrocarbon Fuels: Design and Feasibility Study." Scholar Commons, 2016. http://scholarcommons.usf.edu/etd/6102.

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This paper will discuss the conversion of gas produced from biomass into liquid fuel through the combination of naturally occurring processes, which occur in landfills and anaerobic digesters, and a gas-to-liquids (GTL) facility. Landfills and anaerobic digesters produce gases (LFG) that can be converted into syngas via a Tri-reforming process and then synthesized into man-made hydrocarbon mixtures using Fischer-Tropsch synthesis. Further processing allows for the separation into liquid hydrocarbon fuels such as diesel and gasoline, as well as other middle distillate fuels. Conversion of landfill gas into liquid fuels increases their energy density, ease of storage, and open market potential as a common “drop in” fuel. These steps not only allow for profitable avenues for landfill operators but potential methods to decrease greenhouse gas emissions. The objective of this paper is to present a preliminary design of an innovative facility which processes contaminated biogases and produces a valuable product. An economic analysis is performed to show feasibility for a facility under base case scenario. A sensitivity analysis is performed to show the effect of different cost scenarios on the breakeven price of fuel produced. Market scenarios are also presented in order to further analyze situations where certain product portions cannot be sold or facility downtime is increased. This facility is then compared to traditional mitigation options, such as flaring and electricity generation, to assess the effect each option has on cost, energy efficiency, and emissions reduction.

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37

Olofsson, Fanny, and Henrik Halvarsson. "SMALL SCALE ENERGY CONVERSION OF PLASTIC WASTE : Identification of gasification process parameters through modelling in Aspen Plus." Thesis, Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-49162.

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The present work investigates further development of a small-scale fixed bed batch operating gasification pilot system intended to be used as a waste-to-energy process to reduce littering of PET-bottles on Pemba Island in Tanzania. By developing a simplified gasification model and identifying the most important parameters to obtain a syngas with a lower heating value suitable for combustion and maximizing the overall efficiency and cold gas efficiency. By a literature study the most important parameters were identified along with how the methodology for developing the model and selection of modelling software. The model was developed as an equilibrium-based model in Aspen Plus representing the pilot system, the most important parameters was identified as equivalence ratio and temperature. Multiple scenarios, regarding sensitivity analysis of these parameters was conducted to determine how the outcome of the process was affected. The model was validated against a reference study and was proven to be accurate with small variations. High content of methane and carbon monoxide promoted the highest lower heating value which was at an equivalence ratio of 0.25 and a temperature of 450°C, which also indicated the highest overall efficiency. Increasing the temperature favoured the carbon monoxide content and the cold gas efficiency but indicated a decrease in lower heating value and overall efficiency. It was concluded that the optimal operational conditions were at an equivalence ratio at 0.25 and a temperature at 450°C. At these conditions, the formation of by-products from the gasification is higher than at higher equivalence ratios and temperature which needs to be further investigated through experimental work. It was also concluded that the system could benefit to operate in a semi- batch configuration with a higher equivalence ratio to utilize the excess heat from the process.

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38

Brown, Ashlie M. "Improved thermal energy utilization through coupled and cascaded cooling cycles." Thesis, Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/31645.

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Thesis (M. S.)--Mechanical Engineering, Georgia Institute of Technology, 2010.
Committee Chair: Dr. Srinivas Garimella; Committee Member: Dr. Samuel Graham; Committee Member: Dr. Sheldon Jeter. Part of the SMARTech Electronic Thesis and Dissertation Collection.

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39

Shin, Jieun S. M. Massachusetts Institute of Technology. "Biological conversion of organic municipal solid waste to lactic acid : a techno-economic performance assessment study for commercialization." Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/115031.

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Thesis: S.M. in Technology and Policy, Massachusetts Institute of Technology, School of Engineering, Institute for Data, Systems, and Society, Technology and Policy Program, 2017.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 77-82).
This thesis assesses the economic viability and commercial potential of a lab-scale microbial technology to produce lactic acid (LA), which was developed as a novel technology option for organic waste treatment. Among various available technologies for the separation and purification of LA, the method of esterification-hydrolysis with reactive distillation was selected for this assessment. The process from organic waste to high-purity LA was designed and modeled using Aspen Plus, from which material and energy balances, equipment costs, and utility costs were derived. An economic performance assessment model was developed to estimate capital and operating expenses as well as net present value (NPV), for evaluating the economic feasibility under various scenarios. Monte Carlo techniques were incorporated into the model to take into account the effect of identified uncertainties on the economic performance, which generates distribution profiles rather than single-value estimates. The baseline NPV for polymer-grade LA (99%) production was estimated to be USD 1.95 million in the U.S. and USD 1.31 million in India. Even though the estimated capital and operating expenses are much lower in India, the process was found to be less profitable than in the U.S. The main reason for this is because landfill tipping fees cannot be relied on as a stable revenue source in India. Moreover, two other applications, which this technology could be potentially commercialized for, were also evaluated using the developed models, and the economic performance of each application was compared. Finally, this thesis proposes a Technology Commercialization Assessment Matrix (TCAM), based on the results and insights gained from the assessment conducted.
by Jieun Shin.
S.M. in Technology and Policy

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40

Ben, Haoxi. "Thermal conversion of biomass and biomass components to biofuels and bio-chemicals." Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/51738.

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This thesis examined the conversions of biomass and biomass components to petrochemicals and total aliphatic gasoline like products. There are three major projects of the thesis. Since biomass is very complicated, to understand the thermal decomposition pathways of biomass, the pyrolytic behaviors of various biomass components including lignin and cellulose under different reaction were investigated in the first phase. Due to complexity and limited volatility, the thermal decomposition products from biomass bring insurmountable obstacles to the traditional analysis methods such as GC-MS, UV and FT-IR. Therefore, precise characterization of the whole portion of thermal decomposition products has significant impacts on providing insight into the pyrolysis pathways and evaluating the upgrading processes. Various NMR methods to characterize different functional groups presented in liquid and solid pyrolysis products by 1H, 13C, 31P, 2D-HSQC and solid state 13C-NMR were introduced in the second phase. Nevertheless, the major drawback towards commercialization of pyrolysis oils are their challenging properties including poor volatility, high oxygen content, molecular weight, acidity and viscosity, corrosiveness and cold flow problems. In situ upgrading the properties of pyrolysis oils during thermal conversion process by employing zeolites has been discussed in the third phase. The further hydrogenation of pyrolysis oils to total aliphatic gasoline like products by heterogeneous catalysis in “green medium” – water has also been examined in the third project.

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41

Taylor, Stephen H. "Analytical Modeling and Optimization of a Thermoelectric Heat Conversion System Operating Betweeen Fluid Streams." BYU ScholarsArchive, 2011. https://scholarsarchive.byu.edu/etd/2813.

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Analytical, closed-form solutions governing thermoelectric behavior are derived. An analytical model utilizing a thermal circuit is presented involving heat transfer into, through, out of, and around a thermoelectric device. A nondimensionalization of the model is presented. Linear heat transfer theory is applied to the model to obtain a series of closed form equations predicting net power output for the thermoelectric device. Fluid streams flowing through shrouded heat sinks with square pin fins are considered for the thermal pathways to and from the device. Heat transfer and pressure drop are characterized in a manner conducive to an analytical model using previously published experimental results. Experimental data is presented which validates and demonstrates the usefulness of the model in predicting power output for commercially available thermoelectric generators. A specific design for a thermoelectric power harvester is suggested consisting of a pattern of thermoelectric generators. An economic model for calculating payback time is developed. An optimization process is demonstrated that allows for the payback time of such a system to be minimized through optimization of the physical design of the system. It is shown that optimization of the thermal pathways dramatically reduces payback time. Optimized design of a system is discussed in light of theoretical cases with feasible payback times.

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42

Almustapha, Muhammad Nurudeen. "Modification of a sulphated zirconia catalyst using calcium carbide for conversion of plastic waste into non-aromatic liquid hydrocarbons." Thesis, Heriot-Watt University, 2016. http://hdl.handle.net/10399/3112.

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Plastic consumption has increased 8% annually since the 1950 reaching an estimated 300 million tonnes in 2014, where more than 50% was discarded after single-use. Many recycling methods have been proposed to manage this growing waste, but most have practical, environmental and economic limitations. Catalytic conversion, a chemical recycling method using a suitable catalyst, has been suggested as a viable option since it can return plastic to a chemical feedstock, which is the aim of this work. Four potential catalysts, namely sulphated zirconia SZ, calcium carbide CC, molybdenum carbide MC and zirconium oxide ZO were tested for HDPE conversion, which was selected from five different polymer samples due to its high thermal resistance. It was found that only calcined SZ and calcined CC showed some impact HDPE conversion. However, SZ was marked with high coke yield while calcined CC had low conversion with virtually no coke. Therefore a hybrid catalyst was considered, where the SZ and the CC were mixed together on equal weight bases forming the hybrid catalyst SZ1CC1. Fixed bed pyrolysis showed an excellent HDPE conversion of virtually 100wt% using the hybrid catalyst at 410oC with 66.0wt% liquid yield against a 98.0wt% conversion with only 39.0% liquid yield for the pure SZ and no conversion in the case of HDPE only. The hydrocarbon composition of the liquid fraction obtained changed significantly from 58% aromatic and 16% paraffinic for the SZ to 74% olefinic and 23% naphthenic for the SZ1CC1. The improvement in liquid yield and selectivity to non-aromatic liquid was strongly linked to a modification in the acidic strength of the hybrid catalyst SZ1CC1. The moderation in acidity and textural properties, such as surface area and porosity were found to suppress excessive cracking and limiting secondary cracking reactions, that promotes high gas yield and aromatisation in the SZ. Overall, it is concluded that the SZ on its own, which had high acidic strength and large surface area, promoted secondary reactions during HDPE cracking that yielded aromatics. However, the hybrid catalyst SZ1CC1, which had moderate acid strength and low surface area halted any secondary reaction and terminated the cracking reaction at stages that produced only olefinic and naphthenic hydrocarbons.

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Dang, Yu. "Value-added Conversion of Waste Cooking Oil, Post-consumer PET Bottles and Soybean Meal into Biodiesel and Polyurethane Products." The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1468591615.

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44

Adefeso, Ismail Babatunde. "Techno-economic analysis of a gasification system using refuse-derived fuel from municipal solid waste." Thesis, Cape Peninsula University of Technology, 2017. http://hdl.handle.net/20.500.11838/2753.

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Thesis (Doctor of Engineering in Chemical Engineering)--Cape Peninsula University of Technology, 2017.
The search for alternatives to fossil fuel is necessary with a view to reducing the negative environmental impact of fossil fuel and most importantly, to exploit an affordable and secured fuel source. This study investigated the viability of municipal solid waste gasification for a fuel cell system. Potential solid fuels obtained from the study in the form of refuse-derived fuel (RDF) had high heating value (HHV) between 18.17 MJ/Kg - 28.91 MJ/Kg with energy density increased from 4142.07 MJ/m3 to 10735.80 MJ/m3. The molecular formulas of RDF derived from Ladies Smith drop-off site, Woodstock drop-off site and an average molecular formula of all thirteen municipal solid waste (MSW) disposal facilities were CH1.43O1.02, CH1.49O1.19, and CH1.50O0.86 respectively. The comparative ratios of C/H were in the range of 7.11 to 8.90. The Thermo Gravimetric Analysis showed that the dehydration, thermal decompositions, char combustions were involved in the production of gaseous products but flaming pyrolysis stage was when most tar was converted to syngas mixture. The simulation of RDF gasification allowed a prediction of the RDF gasification behaviour under various operating parameters in an air-blown downdraft gasifier. Optimum SFR (steam flowrate) values for RDF1, RDF2 and RDF3 were determined to be within these values 2.80, 2.50 and 3.50 and Optimum ER values for RDF1, RDF2 and RDF3 were also determined to be within these values 0.15, 0.04 and 0.08. These conditions produced the desired high molar ratio of H2/CO yield in the syngas mixture in the product stream. The molar ratios of H2/CO yield in the syngas mixture in the product stream for all the RDFs were between 18.81 and 20.16. The values of H2/CO satisfy the requirement for fuel cell application. The highest concentration of heavy metal was observed for Al, Fe, Zn and Cr, namely 16627.77 mg/Kg at Coastal Park (CP), 17232.37 mg/Kg at Killarney (KL), 235.01 mg/Kg at Tygerdal (TG), and 564.87 mg/Kg at Kraaifontein (KF) respectively. The results of quantitative economic evaluation measurements were a net return (NR) of $0.20 million, a rate of return on investment (ROI) of 27.88 %, payback time (PBP) of 2.30 years, a net present value (NPV) of $1.11 million and a discounted cash flow rate of return (DCFROR) of 24.80 % and 28.20 % respectively. The results of the economic evaluations revealed that some findings of the economic benefits of this system would be viable if costs of handling MSW were further quantified into the costs analysis. The viability of the costs could depend on government responsibility to accept costs of handling MSW.

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45

Tucker, Chelsea Lyn. "Waste to fuel: designing a cobalt based catalyst and process for once-through Fischer-Tropsch synthesis operated at high conversion." Doctoral thesis, Faculty of Engineering and the Built Environment, 2021. http://hdl.handle.net/11427/33059.

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The production of fuels from waste on a small-scale decentralized level may enhance the liquid fuel security of Sub-Saharan Africa. The Fischer-Tropsch process can be used to convert waste into drop-in fuels. However, operating at small scale in remote locations requires a plant design with lower capital requirements, a greater level of simplicity and utility self-sufficiency. A plant design using an air-fed biogas reformer (without an air separation unit) and a single pass Fischer-Tropsch configuration is proposed. A fundamental requirement of this particular design is that it needs to operate at a higher FischerTropsch conversion than typically seen in industry (55 – 65%). High conversion conditions result in a high partial pressure of H2O and low partial pressures of CO and H2 within the Fischer-Tropsch reactor. These conditions have been reported to negatively affect the activity, selectivity and stability of cobalt-based catalysts. To date, no study has investigated the cause of this phenomenon, nor has a catalyst been developed specifically to operate under high conversion conditions. The objective of this study is to investigate the mechanisms behind these phenomena and provide catalyst design improvements that facilitate operation at high conversion conditions. Furthermore, a detailed design of the proposed once-through Fischer-Tropsch biogas-to-fuel plant will be evaluated using data from the catalytic experiments. An investigation into the effect of high conversion on the activity and selectivity of 0.05Pt-22Co/Al2O3 was conducted in a slurry bed reactor at T = 220°C, P = 20 bar, with a feed simulating synthesis gas generated from air-blown reforming (H2:CO:N2= 4:2:6). Space velocity was decreased to increase conversion to between XCO = 40% and XCO = 97%. The rate of CO consumption decreased with increasing conversion. Increasing the CO conversion was found to have negligible effect on CO2 selectivity (an unwanted by-product) up to a CO conversion of 75%, after which a strong increase was observed. This was attributed to the enhanced of water-gas shift activity of Co0 under hydrothermal conditions. The production of CO2 raised the H2/CO ratio within the reactor resulting in a large increase in the CH4 selectivity (an unwanted by-product), a decrease in the chain growth probability and thus a decrease in the C5+ selectivity (fuel product). In order to improve unfavourable selectivity obtained at high conversion in the Fischer-Tropsch synthesis, the effect of adding manganese (Mn) to 0.05Pt-22Co/Al2O3 was explored. The catalyst (0.05Pt22Co/Al2O3) was impregnated with increasing amounts of manganese, resulting in six Mn-Pt-Co/Al2O3 catalysts with Mn:Co mass ratios of 0, 0.04, 0.09, 0.14, 0.23 and 0.47:1. The optimal level of manganese promotion was found at a Mn:Co mass ratio of 0.14:1. At this level of manganese promotion, CO2 and CH4 selectivity was decreased by up to 6 C-% and 12 C-% (XCO = 90%) respectively whilst turn-over frequency was improved by 100%. The maximum in the C5+ yield as a function of CO-conversion was shifted from XCO = 78% to XCO = 91%, thus making operation at high conversion feasible from an activity and selectivity perspective. Operating Pt-Co/Al2O3 at conversion levels higher than XCO = 70% was shown to lead to rapid irreversible deactivation, with a total activity loss of 50% between XCO = 70% and 97%. Using a combination of spent catalyst characterisation via transmission electron microscopy, temperature programmed reduction/hydrogenation as well as an in-situ magnetometer, this irreversible deactivation was attributed to both sintering and cobalt aluminate formation. At very high conversion (XCO > 97%) enhanced reversible deactivation was exhibited due to the oxidation and re-reduction Co0 to Co(II)O. This oxidation/reduction cycle is the result of a thermodynamic conversion limit: at a mean Co0 crystallite size of 6 nm (as obtained with Pt-Co/Al2O3), the maximum achievable conversion (assuming a lognormal distribution of crystallites, σ = 0.5) is XCO = 88%. A log-normal distribution of cobalt crystallites with an average size of 8 nm (and the same variance) is required to obtain a maximum conversion of up to XCO = 98%. In order to limit deactivation due to cobalt aluminate formation at conversions higher than XCO = 70%, zinc aluminate was investigated as a novel support material for a platinum promoted cobalt catalyst. Zinc aluminate thermodynamically limits the formation of cobalt aluminate and facilitates the formation of larger sized cobalt crystallites. The catalyst, 0.04Pt-23Co/ZnAl2O4 exhibited minimal signs of irreversible deactivation at high conversion with a total rate loss of 0.08 mmol /min/g (0.62 to 0.54 mmol /min/g), whilst the rate loss over 0.05Pt-22Co/Al2O3 amounted to 0.47 mmol /min/g (from 0.74 to 0.27 mmol /min/g). The zinc aluminate supported catalyst exhibited equal selectivity towards CO2, CH4 and C5+ as PtCo/Al2O3 and an improved turnover frequency, thus making it a viable replacement support for cobalt under high conversion conditions. A once-through waste-to-fuel process (using biogas from the anaerobic digestion of waste as a raw material) was designed using the experimentally determined selectivity and activity data from the FischerTropsch synthesis. The syngas generation step of this design incorporates a tri-reformer and water-gas shift reactor. Syngas is then fed into the Fischer-Tropsch reactor, which produces largely waxy products at lower conversions (XCO = 60%) and largely naphtha/distillate products at higher conversions (XCO > 80%). The Fischer-Tropsch products were partially refined to distillate (low density diesel) by means of flash tanks and an atmospheric distillation column. At lower conversion levels, a hydrocracker must be used to improve distillate yields. All light hydrocarbons and syngas are fed to a combined cycle power plant, which produced electricity for the plant, thus satisfying the plant's utility self-sufficiency objective. The plant design was evaluated to find an optimal conversion at which to operate, and to gauge the effectiveness of the catalyst design improvements. An optimal conversion of XCO = 80% was found for Mn-Co/Al2O3 (Mn:Co = 0.14) at a production level of 329 bbl/day distillate from a feed of 16 tonnes of municipal solid waste per hour. This represents a 12% increase in production of distillate when compared to Pt-Co/Al2O3 at the same conversion. A shift from an alumina support to a zinc aluminate support will be necessary as the optimal conversion for this process lies above the XCO = 70% deactivation threshold.

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Abuzed, Sami A. Saad. "Photovoltaic power conversion : improvements to maximum power tracking algorithms and the repurposing of waste power supplies in battery charger applications." Thesis, University of Sheffield, 2015. http://etheses.whiterose.ac.uk/11581/.

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47

Jingxi, Estella Zandile. "Forward osmosis : a desalination technology for the textile industry." Thesis, Cape Peninsula University of Technology, 2017. http://hdl.handle.net/20.500.11838/2674.

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Thesis (MTech (Chemical Engineering))--Cape Peninsula University of Technology, 2017.
Similar to the energy crisis, the critical state of the water supply in South Africa (SA) is a combination of (i) resource exhaustion and pollution; (ii) increasing demand; and (iii) poor infrastructure. Despite its importance, water is the most poorly managed resource in the world. The disposal of industrial effluents contributes greatly to the poor quality of water. The textile industry consumes great quantities of water and produces enormous volumes of wastewater which requires appropriate treatment before being released into the environment. In an attempt to address the water issues, research globally has focused on advanced technologies such as desalination to increase limited pure water resources. The need for alternative desalination methods for the production of clean water from alternative water resources, such as seawater and brackish water, has gained worldwide attention. Reverse osmosis (RO) and Nanofiltration (NF) have been used as unswerving approaches to yield freshwater. Forward osmosis (FO) is a developing membrane technology that has increased substantial attention as a possible lower-energy desalination technology. However, challenges such as suitable FO membranes, membrane fouling, concentration polarisation, and the availability of effective draw solutions (DS), limit FO technology. FO is seeking more importance in novel areas where separation and recovery of the DS is not required. The aims of this study was to: i) identify alternative water resources and evaluate their potential as suitable feed solution (FS); ii) Identify dyes and evaluate their potential as suitable draw solutions (DS) at different concentrations; iii) assess the use of aquaporin biomimetic membrane and iv) assess a FO system for the production of dye solutions. Osmotic pressure (OP) is the pressure exerted by the flow of water through semi-permeable membrane, separating two solutions with different concentrations of solute. The DS should always have OP higher than the FS in order to achieve high water flux. Three basic dyes (i.e. Maxilon Turquoise, Red and Blue) and three reactive dyes (i.e. Carmine, Olive Green and Black) were selected, based on their common use in the SA textile industry. The respective dye samples were prepared at different concentrations and dye-to-salt mass ratios ranging from 1:10 to 1:60 and assessed for OP using a freezing point osmometer. A lab-scale FO unit was used for all the studies. Feed and draw channels were circulated in a counter-current flow at a volumetric flow rate of 600 mL/min. Feed solutions(FS) included deionised water (DI) as a control, brackish water (BW), synthetic seawater (SSW) and textile wastewater (TWW) collected from two textile factories. OP of the FS (DI, BW5, SSW and SW, Factory 1 and Factory 2) was 0, 414, 2761, 2579, 1505 and 3308 kPa, respectively. Basic Blue and Reactive Black generated a higher OP compared to other selected dyes in the study and were therefore selected to be used as DS at a 1:10 dye-to-salt ratio and 0.02 M concentration. An aquaporin biomimetic FO membrane (Aquaporin, Denmark) was used for all the experiments conducted in the FO mode.

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Bradfield, Frances Louise. "Examination of the thermal properties of municipal solid waste and the scalability of its pyrolysis." Thesis, Stellenbosch : Stellenbosch University, 2014. http://hdl.handle.net/10019.1/86670.

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Thesis (MEng)--Stellenbosch University, 2014.
ENGLISH ABSTRACT: Concerns surrounding the world’s current dependence on quickly depleting fossil fuels and their negative environmental impacts have brought about much research into renewable and sustainable energy sources. With population and economic growth not only is this dependence increasing but there is an increasing production of waste by society in general. With space becoming a premium commodity and environmental protection a necessity, landfilling of the majority of the world’s waste is no longer feasible. Thus, research is being carried out into waste-to-energy (WTE) processes and refuse derived fuels (RDF). This study focuses on thermochemical conversion, specifically pyrolysis of solid wastes as a means of energy product recovery. Before a specific waste stream can be used in WTE or RDF contexts its composition and degradation behaviour needs to be investigated. For this reason, a full physical characterisation of the municipal solid waste (MSW) from the Stellenbosch municipality was carried out. It was found that the composition of waste differs between areas within the municipality but the composition of the waste in general compares well with international data. It was found that six main components present in the recyclables stream; namely high and low density polyethylene (HD/LDPE), poly(ethylene terephthalate) (PET), glossy paper, office paper and newspaper would be suitable for thermochemical conversion. The thermal properties and pyrolytic degradation of these six components were investigated by multi heating rate thermogravimetric analysis (TGA) from which kinetic parameters (activation energy, pre-exponential factor and kinetic rate constants) were calculated by a differential isoconversional method. The volatiles released during degradation were identified by way of online mass spectrometry (TGA-MS) yielding six individual kinetic schemes. In order to gauge to what extent milligram pyrolytic experimentation (TGA-MS) can be used to predict larger scale pyrolytic behaviour, runs were performed on one plastic (HDPE) and one paper (glossy paper) sample on a gram scale pyrolytic plant under both slow and vacuum conditions. It was found that, especially for high thermal conductivity samples, yields on gram scale experimentation can be accurately predicted on a milligram scale. Further, the compositions of slow pyrolysis oils from glossy paper, obtained by gas chromatography–mass spectrometry (GC-MS), were compared to TGA-MS results as well as off gases captured from TGA runs by thermal desorption (TGA/TD-GC-MS). It was found that TGA-MS and TGA/TD-GC-MS can be used to predict the main functional groups in pyrolysis oil produced on a gram scale. Thus small scale experimentation can be used to determine the suitability of different waste components for pyrolytic conversion.
AFRIKAANSE OPSOMMING: Kommer oor die wêreld se huidige afhanklikheid van fossielbrandstowwe en die negatiewe uitwerking op die omgewing het baie navorsing oor hernubare en volhoubare energie bronne meegebring. Bevolking en ekonomiese groei veroorsaak 'n toename in hierdie afhanklikheid en in die produksie van afval deur die samelewing. Daar is baie min onbenutte grond oop en die beskerming van die omgewing het noodsaaklik geword. Dus is storting van die meeste van die wêreld se afval nie meer ‘n aanvaarbare opsie nie. As gevolg daarvan word daar tans navorsing in afval-tot-energie (ATE) prosesse en afval afgeleide brandstowwe (AAB) gedoen. Hierdie studie fokus op die termochemiese omskakeling van afval, spesifiek pirolise, as 'n methode vir energie-produk hernuwing. Voordat 'n spesifieke afvalstroom gebruik kan word as 'n AAB moet die samestelling en afbrekings gedrag eers ondersoek word. Daarom is 'n volledige fisiese karakterisering van die munisipale afval (MA) van Stellenbosch munisipaliteit uitgevoer. Resultate het getoon dat daar ‘n verskil in die samestelling van afval tussen die gebiede binne die munisipaliteit is. Afgesien daarvan vergelyk die samestelling van die afval in die algemeen goed met internasionale data. Daar is gevind dat daar ses belangrike komponente teenwoordig is in die herwinbare stroom wat geskik sou wees vir termochemiese omskakeling, naamlik; hoë en lae digtheid poliëtileen (HD/LDPE), poli(etileen tereftelaat) (PET), glans, kantoor en koerant papier. Die termiese eienskappe en termiese afbreking van hierdie ses komponente is ondersoek deur middel van multi-verhittimgs tempo termogravimetriese analise (TGA) waaruit kinetiese parameters (aktiveringsenergie, pre-eksponensiële faktor en kinetiese snelheidskonstantes) deur 'n differensiële omskakelings metode bereken is. Die vlugtige komponente wat tydens die afbreking vrygestel is, is geïdentifiseer deur aanlyn-massaspektrometrie (TGA-MS) wat ses individuele kinetiese skemas verskaf. Om vas te stel tot watter mate milligram pirolitiese eksperimente (TGA-MS) gebruik kan word om op ‘n groter skaal die pirolitiese gedrag te kan voorspel, is eksperimentele lopies op een plastiek- (HDPE) en een papier (glans papier) monster op 'n laboratorium skaal pirolise opstelling onder stadige- en vakuum omstandighede uitgevoer. Daar is gevind dat, veral met hoë hitte geleiding komponente, die opbrengs op gram skaal eksperimente akkuraat voorspel kan word op ‘n milligram skaal. Verder was die samestelling van die stadige pirolise olies uit glans papier, wat verkry word deur gaschromatografie-massaspektrometrie (GC-MS), vergelyk met TGA-MS resultate sowel as af-gasse gevang van TGA lopies deur termiese desorpsie (TGA/TD-GC –MS). Daar is gevind dat TGA-MS en TGA/TD-GC-MS gebruik kan word om die belangrikste funksionele groepe in pirolise olie, wat op 'n gram skaal geproduseer word, te voorspel. Dus kan milligram eksperimente gebruik word om die geskiktheid van afval komponente vir pirolitiese omskakeling te bepaal.

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49

Perondi, Daniele. "Conversão termoquímica do resíduo do triturador de sucata (RTS) de uma siderúrgica." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2017. http://hdl.handle.net/10183/164624.

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Diferentes resíduos são gerados pelas indústrias siderúrgicas, dentre eles o resíduo dos trituradores de sucata (RTS). O destino mais utilizado para o RTS pelas indústrias siderúrgicas brasileiras é o aterro de resíduos industriais. A pirólise se apresenta como uma alternativa para o reaproveitamento do RTS. O objetivo deste trabalho foi avaliar o efeito de diferentes parâmetros operacionais sobre as propriedades e o rendimento dos produtos do processo de pirólise do RTS para fins de um posterior aproveitamento. Um reator de pirólise de leito fixo foi utilizado e as seguintes variáveis foram testadas fazendo-se uso de um planejamento experimental 2k: temperatura (500, 600 e 700 ºC), taxa de aquecimento (5, 20, 35 ºC/min), vazão de gás inerte (N2) (0,03, 0,44 e 0,76 L/min) e razão CaO/RTS (0, 1 e 2). A utilização de uma taxa de aquecimento menor, associada a presença de CaO, resultou nos maiores rendimentos de gás não-condensável (> 50%). O poder calorífico deste gás, aumentou com o incremento da razão CaO/RTS. Este aumento foi atribuído a captura in situ do CO2. A utilização de uma vazão maior de gás inerte, também favoreceu o aumento do poder calorífico do gás não-condensável. Os maiores valores obtidos (25 MJ/Nm3) são apreciáveis, considerando o poder calorífico de outros combustíveis. Os maiores rendimentos de char (> 24%) foram obtidos nos experimentos com a utilização de uma temperatura menor, associada a ausência de CaO. A utilização de uma taxa de aquecimento mais elevada resultou em maiores rendimentos de voláteis condensáveis. Os menores rendimentos de voláteis condensáveis foram obtidos quando a vazão de inerte foi menor. Também foi possível verificar que, houve um aumento do rendimento de voláteis condensáveis com a presença de CaO para a temperatura de 700 ºC. Este comportamento foi atribuído ao maior rendimento global de estireno nas referidas condições operacionais. O rendimento global de 2,4-dimetil-1-heptano também apresentou comportamento semelhante ao observado para o rendimento de voláteis condensáveis, indicando que o AlCl3 pode ter atuado como catalisador da pirólise do PP presente no RTS. Com o aumento da razão CaO/RTS, houve uma redução da concentração de CO2. A redução da concentração de CO2 na presença de CaO está associada a formação de CaCO3. A retenção de cloro no char foi mais elevada nos ensaios conduzidos na presença de CaO. Verificou-se uma redução da retenção de cloro no char com o aumento da temperatura para os ensaios conduzidos na presença de CaO. Uma diminuição da retenção de metais no char foi verificada nos experimentos conduzidos com CaO para os seguintes metais: Co, Cu, Cr, Fe, Ni e Zn. A remoção do cloro permitiria conduzir o processo de pirólise a temperaturas mais elevadas, aumentando a Eficiência Energética mínima (EE) do processo. Desta forma, fica clara a necessidade da remoção do cloro do RTS antes do processo de pirólise, pois a partir disto o uso do CaO contribuiria para o aumento da EE e da retenção de metais no char, e consequentemente da desejabilidade global.
Different wastes are generated by steel industries, among them the shredder residue (SR). The most commonly used destination for SR by Brazilian steel industry is the landfill of industrial waste. The pyrolysis can be considered a solution to this problem. The aim of this work was to evaluate the effects of different operating parameters upon the properties and yield of the SR pyrolysis process products for later use. A fixed bed pyrolysis reactor was used and the following variables were tested using a 2k experimental design: temperature (500, 600 and 700 ºC), heating rate (5, 20, 35 ºC/min), flow rate of inert gas (N2) (0.03, 0.44 and 0.76 L/min) and CaO/SR ratio (0, 1 and 2). The use of a lower heating rate, associated with the CaO presence, resulted in higher yields of non-condensable gas (> 50%). The calorific value of this gas increased with the growth of the CaO/SR ratio. This increase was attributed to an in situ CO2 capture. The use of a higher flow rate of inert gas also favored the increase in the calorific power of the non-condensable gas. The highest values (25 MJ/Nm3) are appreciable considering the calorific value of other fuels. The highest char yields (> 24%) were obtained in the experiments using a lower temperature associated with the absence of CaO. The use of a higher heating rate resulted in higher yields of condensable volatiles. The lower yields of condensable volatiles were obtained when the inert flow rate was lower. It was also possible to verify that there was an increase in the condensable volatiles yield with the CaO presence at a temperature of 700 ºC.This behavior was attributed to the higher styrene overall yield under these operating conditions. The 2,4-dimethyl-1-heptane overall yield also presented a similar behavior to that observed for the condensable volatiles yield, indicating that the AlCl3 may have acted as a catalyst for the PP pyrolysis present in the SR. With the increase in the CaO/RTS ratio, there was a reduction in the CO2 concentration. The CO2 concentration reduction in the CaO presence is associated with the CaCO3 formation. The chlorine retention in the char was higher in the experiments conducted with CaO presence. A reduction in the chlorine retention in char was observed with increasing temperature for the experiments conducted with CaO presence. A decrease in metal retention in the char was verified in the experiments conducted with CaO for the following metals: Co, Cu, Cr, Fe, Ni and Zn. Chlorine removal would allow the pyrolysis process to be conducted at higher temperatures, increasing the minimum energy efficiency (EE) of the process. Therefore, it is clear the need to remove chlorine from the SR before the pyrolysis process, since, the CaO use would contribute to the EE increase and the retention of metals in the char, and consequently the global desirability.

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50

Fadhila, Audinisa. "Integrating novel circular economy technologies in complex trans-sector value chains : Case study of insect larvae conversion technology within waste and feed value chains." Thesis, KTH, Hållbar utveckling, miljövetenskap och teknik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-284339.

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Even as the current linear value chains (LVC) of organic waste and animal feed hold the potential to become circular, these practices continue to pose major environmental risks such as deforestation and overfishing. Therefore, a novel circular value chain (CVC) is proposed, connecting the organic waste stream with animal feed production by the use of insect-based organic waste conversion technology. The Black Soldier Fly (BSF) is chosen as the insect-based conversion technology since it has nutritional properties, which serves both waste treatment and animal feed material production purposes. Although there are already initiatives and collaborations in the Swedish context, the transition has not yet been successful. The study aims to identify and propose required solutions for the value chain transition. By using the transitional study tools of Technological Innovation System (TIS) and Multi Level Perspective (MLP) alongside sustainable value chain transition studies, it is found that technological and information-related adjustments are required to further enable the transition. Technological adjustments are studied from the perspective of Ragn-Sells AB as a potential insect- based organic waste conversion actor. Scenarios to see economical sustainability were designed based on the quantity fluctuation of waste as material input (3,000 tons per year and 15,000 tons per year), possibility of automated operation which affects both investment and operating costs of the facility, and procurement of small BSF larvae (off-site and in-site breeding). From the different scenarios designed, it is found that the scenario with the capacity of 15,000 tons per year, higher investment due to automation, and on-site breeding is the most preferable for the case. To answer information- related needs, an Informational Flow Framework (IFF) is proposed. The IFF consists of “Value Chain Stakeholders”, “CVC Relevant Regulations”, “Information Data Pool”, and “Information Flow”. The framework’s main function is to identify the type of material information required to be distributed in the system and the stakeholders whom require and/or provide various information, with the main goal of increasing the trust among the stakeholders related to material information.
Trots att den nuvarande linjära värdekedjan (Linear Value Chain) för organiskt avfall och djurfoder har potentialen för en cirkulär ekonomi, så utgör den nuvarande praxisen fortfarande stora risker såsom avskogning samt överfiske. Därför föreslås en ny cirkulär värdekedja (Circular Value Chain), som förbinder den organiska avfallsströmmen med djurfoderproduktion med användning av insektbaserad omvandlingsteknologi för organiskt avfall. Svart soldat fluga (Black Soldier Fly/BSF) utses som den insektsbaserade omvandlingsteknologin eftersom den har näringsegenskaper som bistår både avfallsbehandling och djurfoderproduktionsändamål. Trots att det redan finns initiativ och samarbeten i det svenska sammanhanget har övergången ännu inte lyckats. Studien syftar till att identifiera och föreslå nödvändiga lösningar för den cirkuläravärdekedjan. Genom att använda övergångsstudieverktygen av Teknologiskt Innovations System (TIS) samt Multi Level Perspective (MLP) och diverse värdekedjeövergångsstudier, konstateras det att tekniska och informationsrelaterade justeringarkrävs för att ytterligare möjliggöra övergången från en linjär till en cirkulär värdekedja. Teknologiska anpassningar studeras ur Ragn-Sells ABs perspektiv som en potentiell aktör för omvandling av organiskt avfall. Scenarier för att undersöka ekonomisk hållbarhet utformades baserat påfluktuering av mängden avfall som materialinmatning (3,000 ton per år och 15, 000 ton per år), möjlighet till automatiserad drift som påverkar både CAPEX & OPEX i anläggningen (hög CAPEX och låg CAPEX), och upphandling av små BSF-larver (avel utanför anläggningen). Från de olika utformade scenarierna konstaterades att scenariot med en kapacitet på 15,000 ton per år, hög CAPEX och avel på plats är det mest fördelaktiga för Ragn Sells AB. För att besvara informationsrelaterad justering föreslås en informationsflödesram (IFF). IFF består av ”Value Chain Interessholders”, “CVC Relevant Regulations”, “Information Data Pool” och “Information Flow”. Ramens huvudfunktion är att identifiera vilken typ av materialinformation som krävs för att distribueras i systemet och den aktör som kräver och/eller tillhandahåller informationen, med det huvudsakliga målet att öka förtroendet bland aktörerna relaterade till materiell information.

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Дисертації з теми "Wastes conversion"

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