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1
Tam, Tina Sui-Man. "Pyrolysis of oil shale in a spouted bed pyrolyser". Thesis, University of British Columbia, 1987. http://hdl.handle.net/2429/26742.
Testo completoAbstract (sommario):
Pyrolysis of a New Brunswick oil shale has been studied in a 12.8cm diameter spouted bed reactor. The aim of the project was to study the effect of pyrolysis temperature, shale particle size, feed rate and bed material on oil yield. Gas and spent shale yields were also determined. Shale of different particle size ranging from 0.5mm to 4mm was studied using an electrically heated reactor containing sand or spent shale which was spouted with nitrogen or nitrogen/carbon dioxide mixtures.
For a given particle size and feed rate, there is a maximum in oil yield with temperature. For particles of 1-2mm at a feed rate of about 1.4kg/hr, the optimum temperature is at 475°C with an oil yield of 7.1% which represents 89.3% of the modified Fischer Assay yield. For the 2-4mm and the same feed rate, the optimum temperature is 505°C with an oil yield equal to 7.4% which is 94.3% of the modified Fischer Assay value. At a fixed temperature of about 500°C, the oil yield increases with increasing particle size. This trend is in agreement with the Fischer Assay values which showed oil yields increasing from 5.2% to about 8% as the particle size was increased. In the spouted bed, the oil yield decreases as the oil shale feed rate increases at a given temperature. The use of spent shales as the spouting solids in the bed also has a negative effect on oil yield. The gas yields which were low (less than 2.1%) and difficult to measure do not seem to be affected by particle sizes, feed rate and bed material. Hydrogen, methane and other hydrocarbons are produced in very small amounts. C0₂ and CO are not released in measurable yield in the experiments. The trend of the spent shale yield has not been successfully understood due to the unreliability of the particle collection results. Attrition of the spent shale appears to be a serious problem.
Results of the experiments are rationalized with the aid of a kinetic model in which the kerogen in the oil shale decomposes to yield a bitumen and other by products and the bitumen undergoes further decomposition into oil. The spouted bed is treated as a backmixed reactor with respect to the solids. A heat transfer model is used to predict the temperature rise of the shale entering the pyrolyzer.Applied Science, Faculty of
Chemical and Biological Engineering, Department of
Graduate
2
Zanzi, Rolando. "Pyrolysis of biomass. Rapid pyrolysis at high temperature. Slow pyrolysis for active carbon preparation". Doctoral thesis, KTH, Chemical Engineering and Technology, 2001. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3180.
Testo completoAbstract (sommario):
Pyrolysis of biomass consists of heating solid biomass inthe absence of air to produce solid, liquid and gaseous fuels.In the first part of this thesis rapid pyrolysis of wood(birch) and some agricultural residues (olive waste, sugarcanebagasse and wheat straw in untreated and in pelletized form) athigh temperature (800ºC1000ºC) is studied ina free fall reactor at pilot scale. These conditions are ofinterest for gasification in fluidized beds. Of main interestare the gas and char yields and compositions as well as thereactivity of the produced char in gasification.
A higher temperature and smaller particles increase theheating rate resulting in a decreased char yield. The crackingof the hydrocarbons with an increase of the hydrogen content inthe gaseous product is favoured by a higher temperature and byusing smaller particles. Wood gives more volatiles and lesschar than straw and olive waste. The higher ash content inagricultural residues favours the charring reactions. Charsfrom olive waste and straw are more reactive in gasificationthan chars from birch because of the higher ash content. Thecomposition of the biomass influences the product distribution.Birch and bagasse give more volatiles and less char thanquebracho, straw and olive waste. Longer residence time inrapid pyrolysis increase the time for contact between tar andchar which makes the char less reactive. The secondary charproduced from tar not only covers the primary char but alsoprobably encapsulates the ash and hinders the catalytic effectof the ash. High char reactivity is favoured by conditionswherethe volatiles are rapidly removed from the particle, i.e.high heating rate, high temperature and small particles.
The second part of this thesis deals with slow pyrolysis inpresence of steam for preparation of active carbon. Theinfluence of the type of biomass, the type of reactor and thetreatment conditions, mainly temperature and activation time,on the properties and the yield of active carbons are studied.The precursors used in the experiments are birch (wood) anddifferent types of agricultural residues such as sugarcanebagasse, olive waste, miscanthus pellets and straw in untreatedand pelletized form.
The results from the pyrolysis of biomass in presence ofsteam are compared with those obtained in inert atmosphere ofnitrogen. The steam contributes to the formation of solidresidues with high surface area and good adsorption capacity.The yield of liquid products increases significantly at theexpense of the gaseous and solid products. Large amount ofsteam result in liquid products consisting predominantly ofwater-soluble polar compounds.
In comparison to the stationary fixed bed reactor, therotary reactor increases the production of energy-rich gases atthe expense of liquid products.
The raw materials have strong effect on the yields and theproperties of the pyrolysis products. At equal time oftreatment an increase of the temperature results in a decreaseof the yield of solid residue and improvement of the adsorptioncapacity until the highest surface area is reached. Furtherincrease of the temperature decreases the yield of solidproduct without any improvement in the adsorption capacity. Therate of steam flow influences the product distribution. Theyield of liquid products increases while the gas yielddecreases when the steam flow is increased.
Keywords: rapid pyrolysis, pyrolysis, wood, agriculturalresidues,biomass, char, tar, gas, char reactivity,gasification, steam, active carbon
3
Munoz, hoyos Mariana. "Contribution à la compréhension du procédé de spray pyrolyse par une double approche modélisation/expérience". Thesis, Limoges, 2017. http://www.theses.fr/2017LIMO0081/document.
Testo completoAbstract (sommario):
Des poudres céramiques multiéléments dans le système Si/C/N peuvent être obtenues avec le procédé de spray pyrolyse. Les paramètres de synthèse et leur influence sur la composition et la morphologie de poudres obtenues a fait l’objet de précédentes études. Toutefois, les mécanismes de décomposition et de recombinaison des espèces dans la zone de réaction restent inconnus. Cette étude vise à approfondir la compréhension du procédé, de la formation de l’aérosol jusqu’aux mécanismes de formation des particules solides. Ainsi, la caractérisation de l’aérosol par ombroscopie laser, couplée à la mise en place d’un modèle numérique du transport et traitement des gouttes du précurseur au sein du dispositif, a permis l’identification de distributions en taille de gouttes de type bimodal jusqu’à leur entrée en zone de réaction. Cette double approche a également permis de vérifier l’effet des phénomènes physiques et hydrodynamiques sur les distributions en taille des gouttelettes lors de leur transport vers la zone réactionnelle. L’introduction d’une distribution bimodale dans le four de pyrolyse permet d’envisager un mécanisme de décomposition du précurseur en deux étapes, lié à la taille des gouttelettes. Cette hypothèse combinée à l’étude de décomposition du précurseur Hexaméthyldisilazane à haute température a permis de proposer des mécanismes de formation de poudres dont la composition chimique varie selon l’atmosphère de synthèse utiliséeMultielement ceramic powders in the Si/C/N system could be obtained by spray pyrolysis process. Synthesis parameters and their effect on powder chemical composition and morphology have been already studied. Nevertheless, the mechanisms of precursor decomposition and gas phase species recombination that take place in the reaction zone are still unknown. The aim of this study is the comprehension of the process, from the aerosol generation to the solid powders formation mechanisms. The shadowgraphy technique was used to characterize the spray, and coupled with the implementation of a numerical model of droplets transport and treatment through the device allowed to identify bimodal size distributions at the furnace entrance. This double approach let confirm the effect of physical and hydrodynamic phenomenon in drop size evolution. The introduction of a bimodal distribution into the pyrolysis furnace allows to consider a precursor decomposition mechanism in two steps, depending on the drop sizes. This hypothesis combined to the study of precursor decomposition at high temperature led to the proposal of powder formation mechanisms in which their chemical composition varies with the synthesis atmosphere
4
Oh, Myongsook Susan. "Softening coal pyrolysis". Thesis, Massachusetts Institute of Technology, 1985. http://hdl.handle.net/1721.1/15245.
Testo completoAbstract (sommario):
Thesis (Sc. D.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 1985.MICROFICHE COPY AVAILABLE IN ARCHIVES AND SCIENCE.
Bibliography: leaves 275-284.
by Myongsook Susan Oh.
Sc.D.
5
Alkhatib, Radwan. "Development of an alternative fuel from waste of used tires by pyrolysis". Thesis, Nantes, Ecole des Mines, 2014. http://www.theses.fr/2014EMNA0197/document.
Testo completoAbstract (sommario):
L'objectif de ce travail est de valoriser des déchets de pneus usagés par pyrolyse afin d'obtenir un nouveau carburant comparable avec le gazole suivant la norme EN590. L'obtention de ce carburant était réalisée via l'optimisation des conditions de pyrolyse qui sont la température, la vitesse de chauffage (puissance de la résistance électrique) et du débit d'azote. Le rôle de l'azote est limité à purger le réacteur avant le début de la pyrolyse pour 30 minutes système. Le carburant produit est comparable au gazole avec un pouvoir calorifique de 45 MJ/kg, une densité de 0,85 et une teneur en goudron 7%The objective of this work is to get alternative fuel comparable with the available diesel in the market following the EN590. The fuel getting was via optimization of pyrolysis conditions which are temperature, heating rate (power of electrical resistance) and inert gas flow rate. The optimum values are 465°C, 650 Watts and without inert gas flow rate. Inert gas role is limited to purge the system for 30 minutes before start the pyrolysis to get rid of oxidative gases. The obtained product is comparable with the diesel as it has GCV 45 KJ/kg, low density of 0,85 and 7% tar content
6
Melzer, Michael. "Valorisation énergétique des sous-produits agricoles en zone sub-saharienne : pré-conditionnement de la biomasse par pyrolyse flash". Thesis, Compiègne, 2013. http://www.theses.fr/2013COMP2098/document.
Testo completoAbstract (sommario):
L’Afrique de l'Ouest manque de ressources naturelles pour la production d'énergie. Les sous-produits agro-industriels comme les coques d’anacarde (CNS), les tourteaux de jatropha et de karité ont été identifiés comme des ressources disponibles et facilement mobilisables à des fins énergétiques. Ces biomasses se caractérisent par de fortes teneurs en extractibles (baume de cajou=CNSL ou triglycérides), sources de fumées toxiques en combustion. La thèse visait à évaluer la pertinence de la pyrolyse rapide comme procédé alternatif pour ces ressources, etplus particulièrement à établir l'impact des extractibles sur les rendements, la composition et la stabilité des bio-huiles. Les biomasses ont été dérivées en échantillons couvrant la gamme entière des teneurs en extractibles (tourteau déshuilé ~0% ; extractible purs 100%), lesquels ont été caractérisés et pyrolysés dans 2 dispositifs laboratoires (ATG et four tubulaire), puis en conditions réelles sur un pilote de pyrolyse rapide à lit fluidisé. On ne constate pas d'interaction significative entre la matrice solide et les extractibles lors de leur décomposition, mais des produits différents ont été identifiés. Le CNSL se volatilise entre 250 et 320°C ; plusieurs composés phénoliques ou typiques du CNSL brut se retrouvent dans l'huile de pyrolyse. En revanche, les triglycérides se décomposent entièrement entre 380 et 420°C en chaînes d’hydrocarbures linéaires. Quelques produits d'interaction avec les triglycérides et les protéines ont été identifiés. Par ailleurs, les essais sur pilote ont mis en évidence des difficultés opérationnelles dans le lit fluidisé liées aux spécificités des tourteaux, suggérant une optimisation des conditions opératoires. Pour pallier la séparation de phases constatée sur les bio-huiles, des formulations avec d'autres biocarburants ont été testées. Les émulsions obtenues sont plus homogènes, mais leur stabilité physique est encore insuffisante malgré l'ajoutSub-Saharan West Africa lacks of natural resources, especially for energy production. By-products of agro-industry as cashew nut shells (CNS), jatropha (Jc) and shea (Sc) press cakes were identified as available resources for energetic valorisation. These biomasses are characterized by high extractive contents (cashew nut shell liquid/CNSL or triglycerides) which are the reason for toxic fumes during combustion. The thesis investigated the feasibility of flash pyrolysis as alternative process for these resources, more specifically the impact of the extractives on yields, the composition and the stability of flash pyrolysis oils. The feedstock were derived into samples covering the whole range of extractive contents (from de-oiled press cakes, ~0 wt%; to pure extractives, 100 wt%) which were characterized and pyrolysed in two laboratory devices (TGA and tubular furnace), then by applying flash pyrolysis conditions in a fluidized bed reactor. No significant interaction in-between the solid matrix and the extractives during pyrolysis were observed but different products were identified. CNSL volatises between 250 and 320°C, several phenolic compounds and typical compounds of crude CNSL were found to be present in the pyrolysis oil. In contrast, triglycerides are entirely decomposed at 380 to 420°C to give linear hydro-carbon chains. Some interaction products of the triglycerides with proteins were identified. Additionally, the experiments with the pilot plant have shown operational difficulties in the fluidized bed, which are linked to specific properties of the press cakes. Thus, further optimisations of process conditions are suggested. To overcome the observed phase separation of the pyrolysis oils mixtures with other biofuels were studied. The obtained emulsions are more homogeneous but the physical stability is still insufficient despite the addition of surfactants
7
Safdari, Mohammad Saeed. "Characterization of Pyrolysis Products from Fast Pyrolysis of Live and Dead Vegetation". BYU ScholarsArchive, 2018. https://scholarsarchive.byu.edu/etd/8807.
Testo completoAbstract (sommario):
Wildland fire, which includes both planned (prescribed fire) and unplanned (wildfire) fires, is an important component of many ecosystems. Prescribed burning (controlled burning) is used as an effective tool in managing a variety of ecosystems in the United States to reduce accumulation of hazardous fuels, manage wildlife habitats, mimic natural fire occurrence, manage traditional native foods, and provide other ecological and societal benefits. During wildland fires, both live and dead (biomass) plants undergo a two-step thermal degradation process (pyrolysis and combustion) when exposed to high temperatures. Pyrolysis is the thermal decomposition of organic material, which does not require the presence of oxygen. Pyrolysis products may later react with oxygen at high temperatures, and form flames in the presence of an ignition source. In order to improve prescribed fire application, accomplish desired fire effects, and limit potential runaway fires, an improved understanding of the fundamental processes related to the pyrolysis and ignition of heterogeneous fuel beds of live and dead plants is needed.In this research, fast pyrolysis of 14 plant species native to the forests of the southern United States has been studied using a flat-flame burner (FFB) apparatus. The results of fast pyrolysis experiments were then compared to the results of slow pyrolysis experiments. The plant species were selected, which represent a range of common plants in the region where the prescribed burning has been performed. The fast pyrolysis experiments were performed on both live and dead (biomass) plants using three heating modes: (1) convection-only, where the FFB apparatus was operated at a high heating rate of 180 °C s-1 (convective heat flux of 100 kW m-2) and a maximum fuel surface temperature of 750 °C; (2) radiation-only, where the plants were pyrolyzed under a moderate heating rate of 4 °C s-1 (radiative heat flux of 50 kW m-2), and (3) a combination of radiation and convection, where the plants were exposed to both convective and radiative heat transfer mechanisms. During the experiments, pyrolysis products were collected and analyzed using a gas chromatograph equipped with a mass spectrometer (GC-MS) for the analysis of tars and a gas chromatograph equipped with a thermal conductivity detector (GC-TCD) for the analysis of light gases.The results showed that pyrolysis temperature, heating rate, and fuel type, have significant impacts on the yields and the compositions of pyrolysis products. These experiments were part of a large project to determine heat release rates and model reactions that occur during slow and fast pyrolysis of live and dead vegetation. Understanding the reactions that occur during pyrolysis then can be used to develop more accurate models, improve the prediction of the conditions of prescribed burning, and improve the prediction of fire propagation.
8
Ofoma, Ifedinma. "Catalytic Pyrolysis of Polyolefins". Thesis, Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/10439.
Testo completoAbstract (sommario):
Due to the migration of scientists towards green chemistry, landfilling and incineration will no longer be acceptable options for plastics waste disposal in the future. Consequently new methods for recycling plastics and plastic products such as carpets are being researched.
This study serves as a preliminary effort to study the catalytic feedstock recycling of polyolefins, specifically PP and PE, as source for gasoline range fuels, as well as an alternative for plastic waste disposal. Several studies have been conducted on the pyrolysis of waste polyolefins using commercial cracking catalysts (FCC), however, the effect of catalyst size and mode of catalyst dispersion have been studied sparsely. This thesis proposes to study these effects in the catalytic pyrolysis of polypropylene (PP), a component of carpets, using both fresh and used FCC catalysts. The same study will be applied to polyethylene (PE), which accounts for an enormous amount of municipal solid waste in the US today. Furthermore, the catalytic impact of calcium carbonate, a filler component of tufted carpet, will be investigated.
Using thermogravimetric analysis, the global kinetics of the PP pyrolysis using various FCC catalysts will be derived and applied in the modeling of the pyrolysis reaction in a twin screw extruder. Furthermore, an economic analysis on the catalytic pyrolysis of PP is presented.
9
Hugo, Thomas Johannes. "Pyrolysis of sugarcane bagasse". Thesis, Stellenbosch : University of Stellenbosch, 2010. http://hdl.handle.net/10019.1/5238.
Testo completoAbstract (sommario):
Thesis (MScEng (Process Engineering))--University of Stellenbosch, 2010.ENGLISH ABSTRACT: The world’s depleting fossil fuels and increasing greenhouse gas emissions have given rise to much research into renewable and cleaner energy. Biomass is unique in providing the only renewable source of fixed carbon. Agricultural residues such as Sugarcane Bagasse (SB) are feedstocks for ‘second generation fuels’ which means they do not compete with production of food crops. In South Africa approximately 6 million tons of raw SB is produced annually, most of which is combusted onsite for steam generation. In light of the current interest in bio-fuels and the poor utilization of SB as energy product in the sugar industry, alternative energy recovery processes should be investigated. This study looks into the thermochemical upgrading of SB by means of pyrolysis. Biomass pyrolysis is defined as the thermo-chemical decomposition of organic materials in the absence of oxygen or other reactants. Slow Pyrolysis (SP), Vacuum Pyrolysis (VP), and Fast Pyrolysis (FP) are studied in this thesis. Varying amounts of char and bio-oil are produced by the different processes, which both provide advantages to the sugar industry. Char can be combusted or gasified as an energy-dense fuel, used as bio-char fertilizer, or upgraded to activated carbon. High quality bio-oil can be combusted or gasified as a liquid energy-dense fuel, can be used as a chemical feedstock, and shows potential for upgrading to transport fuel quality. FP is the most modern of the pyrolysis technologies and is focused on oil production. In order to investigate this process a 1 kg/h FP unit was designed, constructed and commissioned. The new unit was tested and compared to two different FP processes at Forschungszentrum Karlsruhe (FZK) in Germany. As a means of investigating the devolatilization behaviour of SB a Thermogravimetric Analysis (TGA) study was conducted. To investigate the quality of products that can be obtained an experimental study was done on SP, VP, and FP. Three distinct mass loss stages were identified from TGA. The first stage, 25 to 110°C, is due to evaporation of moisture. Pyrolitic devolatilization was shown to start at 230°C. The final stage occurs at temperatures above 370°C and is associated with the cracking of heavier bonds and char formation. The optimal decomposition temperatures for hemicellulose and cellulose were identified as 290°C and 345°C, respectively. Lignin was found to decompose over the entire temperature range without a distinct peak. These results were confirmed by a previous study on TGA of bagasse. SP and VP of bagasse were studied in the same reactor to allow for accurate comparison. Both these processes were conducted at low heating rates (20°C/min) and were therefore focused on char production. Slow pyrolysis produced the highest char yield, and char calorific value. Vacuum pyrolysis produced the highest BET surface area chars (>300 m2/g) and bio-oil that contained significantly less water compared to SP bio-oil. The short vapour residence time in the VP process improved the quality of liquids. The mechanism for pore formation is improved at low pressure, thereby producing higher surface area chars. A trade-off exists between the yield of char and the quality thereof. FP at Stellenbosch University produced liquid yields up to 65 ± 3 wt% at the established optimal temperature of 500°C. The properties of the bio-oil from the newly designed unit compared well to bio-oil from the units at FZK. The char properties showed some variation for the different FP processes. At the optimal FP conditions 20 wt% extra bio-oil is produced compared to SP and VP. The FP bio-oil contained 20 wt% water and the calorific value was estimated at 18 ± 1 MJ/kg. The energy per volume of FP bio-oil was estimated to be at least 11 times more than dry SB. FP was found to be the most effective process for producing a single product with over 60% of the original biomass energy. The optimal productions of either high quality bio-oil or high surface area char were found to be application dependent.
AFRIKAANSE OPSOMMING: As gevolg van die uitputting van fossielbrandstofreserwes, en die toenemende vrystelling van kweekhuisgasse word daar tans wêreldwyd baie navorsing op hernubare en skoner energie gedoen. Biomassa is uniek as die enigste bron van hernubare vaste koolstof. Landbouafval soos Suikerriet Bagasse (SB) is grondstowwe vir ‘tweede generasie bio-brandstowwe’ wat nie die mark van voedselgewasse direk affekteer nie. In Suid Afrika word jaarliks ongeveer 6 miljoen ton SB geproduseer, waarvan die meeste by die suikermeulens verbrand word om stoom te genereer. Weens die huidige belangstelling in bio-brandstowwe en ondoeltreffende benutting van SB as energieproduk in die suikerindustrie moet alternatiewe energie-onginningsprosesse ondersoek word. Hierdie studie is op die termo-chemiese verwerking van SB deur middel van pirolise gefokus. Biomassa pirolise word gedefinieer as die termo-chemiese afbreking van organiese bio-materiaal in die afwesigheid van suurstof en ander reagense. Stadige Pirolise (SP), Vakuum Pirolise (VP), en Vinnige Pirolise word in hierdie tesis ondersoek. Die drie prosesse produseer veskillende hoeveelhede houtskool en bio-olie wat albei voordele bied vir die suikerindustrie. Houtskool kan as ‘n vaste energie-digte brandstof verbrand of vergas word, as bio-houtskoolkompos gebruik word, of kan verder tot geaktiveerde koolstof geprosesseer word. Hoë kwaliteit bio-olie kan verbrand of vergas word, kan as bron vir chemikalië gebruik word, en toon potensiaal om in die toekoms opgegradeer te kan word tot vervoerbrandstof kwaliteit. Vinnige pirolise is die mees moderne pirolise tegnologie en is op bio-olie produksie gefokus. Om die laasgenoemde proses te toets is ‘n 1 kg/h vinnige pirolise eenheid ontwerp, opgerig en in werking gestel. Die nuwe pirolise eenheid is getoets en vegelyk met twee verskillende vinnige pirolise eenhede by Forschungszentrum Karlsruhe (FZK) in Duitsland. Termo-Gravimetriese Analise (TGA) is gedoen om die ontvlugtigingskenmerke van SB te bestudeer. Eksperimentele werk is verrig om die kwaliteit van produkte van SP, VP, vinnige pirolise te vergelyk. Drie duidelike massaverlies fases van TGA is geïdentifiseer. Die eerste fase (25 – 110°C) is as gevolg van die verdamping van vog. Pirolitiese ontvlugtiging het begin by 230°C. Die finale fase (> 370°C) is met die kraking van swaar verbindings en die vorming van houtskool geassosieer. Die optimale afbrekingstemperatuur vir hemisellulose en sellulose is as 290°C en 345°C, respektiewelik, geïdentifiseer. Daar is gevind dat lignien stadig oor die twede en derde fases afgebreek word sonder ‘n duidelike optimale afbrekingstemperatuur. Die resultate is deur vorige navorsing op TGA van SB bevestig. SP en VP van bagasse is in dieselfde reaktor bestudeer, om ‘n akkurate vergelyking moontlik te maak. Beide prosesse was by lae verhittingstempo’s (20°C/min) ondersoek, wat gevolglik op houtskoolformasie gefokus is. SP het die hoogste houtskoolopbrengs, met die hoogste verbrandingsenergie, geproduseer. VP het hootskool met die hoogste BET oppervlakarea geproduseer, en die bio-olie was weens ‘n dramatiese afname in waterinhoud van beter gehalte. Die meganisme vir die vorming van ‘n poreuse struktuur word deur lae atmosferiese druk verbeter. Daar bestaan ‘n inverse verband tussen die kwantiteit en kwaliteit van die houtskool. Vinnige pirolise by die Universiteit van Stellenbosch het ‘n bio-olie opbrengs van 65 ± 3 massa% by ‘n vooraf vasgestelde optimale temperatuur van 500°C geproduseer. Die eienskappe van bio-olie wat deur die nuwe vinnige pirolise eenheid geproduseer is het goed ooreengestem met die bio-olie afkomstig van FZK se pirolise eenhede. Die houtskool eienskappe van die drie pirolise eenhede het enkele verskille getoon. By optimale toestande vir vinnige pirolise word daar 20 massa% meer bio-olie as by SP en VP geproduseer. Vinnige pirolise bio-olie het ‘n waterinhoud van 20 massa% en ‘n verbrandingswarmte van 18 ± 1 MJ/kg. Daar is gevind dat ten opsigte van droë SB die energie per enheidsvolume van bio-olie ongeveer 11 keer meer is. Vinnige pirolise is die mees doeltreffende proses vir die vervaardiging van ‘n produk wat meer as 60% van die oorspronklike biomassa energie bevat. Daar is gevind dat die optimale hoeveelhede van hoë kwaliteit bio-olie en hoë oppervlakarea houtskool doelafhanklik is.
10
Joubert, Jan-Erns. "Pyrolysis of Eucalyptus grandis". Thesis, Stellenbosch : Stellenbosch University, 2013. http://hdl.handle.net/10019.1/80179.
Testo completoAbstract (sommario):
Thesis (MScEng)--Stellenbosch University, 2013.ENGLISH ABSTRACT: In recent times, governments around the world have placed increasing focus on cleaner technologies and sustainable methods of power generation in an attempt to move away from fossil fuel derived power, which is deemed unsustainable and unfriendly to the environment. This trend has also been supported by the South African government, with clear intentions to diversify the country’s power generation by including, among others, biomass as a renewable resource for electricity generation. Woody biomass and associated forestry residues in particular, could potentially be used as such a renewable resource when considering the large amount of fast growing hardwood species cultivated in South Africa. Approximately 6.3 million ton of Eucalyptus grandis is sold annually for pulp production while a further 7 million ton of Eucalyptus species are sold as round wood. With these tree species reaching commercial maturity within 7 – 9 years in the South African climate, there is real potential in harnessing woody biomass as a renewable energy source. In this study, pyrolysis was investigated as a method to condense and upgrade E.grandis into energy and chemical rich products. The pyrolysis of E.grandis is the study of the thermal degradation of the biomass, in the absence of oxygen, to produce char and bio-oil. The thermal degradation behaviour of E.grandis was studied using thermo-gravimetric analysis (TGA) at the Karlsruhe Institute of Technology (KIT) in Germany and subsequently used to determine the isoconversional kinetic constants for E.grandis and its main lignocellulosic components. Slow, Vacuum and Fast Pyrolysis were investigated and optimised to maximise product yields and to identify the key process variables affecting product quality. The Fast Pyrolysis of E.grandis was investigated and compared on bench (KIT0.1 kg/h), laboratory (SU1 kg/h) and pilot plant scale (KIT10 kg/h), using Fast Pyrolysis reactors at Stellenbosch University (SU) in South Africa and at KIT in Germany. The Slow and Vacuum Pyrolysis of E.grandis was investigated and compared using a packed bed reactor at Stellenbosch University. The TGA revealed that biomass particle size had a negligible effect on the thermal degradation behaviour of E.grandis at a heating rate set point of 50 °C/min. It was also shown that increasing the furnace heating rates shifted the thermo-gravimetric (TG) and differential thermo-gravimetric (DTG) curves towards higher temperatures while also increasing the maximum rate of volatilisation. Lignin resulted in the largest specific char yield and also reacted across the widest temperature range of all the samples investigated. The average activation energies found for the samples investigated were 177.8, 141.0, 106.2 and 170.4 kJ/mol for holocellulose, alpha-cellulose, Klason lignin and raw E.grandis, respectively. Bio-oil yield was optimised at 76 wt. % (daf) for the SU1 kg/h Fast Pyrolysis plant using an average biomass particle size of 570 μm and a reactor temperature of 470 °C. Differences in the respective condensation chains of the various Fast Pyrolysis reactor configurations investigated resulted in higher gas and char yields for the KIT reactor configurations compared to the SU1 kg/h Fast Pyrolysis plant. Differences in the vapour residence time between Slow (>400 s) and Vacuum Pyrolysis (< 2 s) resulted in a higher liquid and lower char yield for Vacuum Pyrolysis. Local liquid yield maxima of 41.1 and 64.4 wt. % daf were found for Slow and Vacuum Pyrolysis, respectively (achieved at a reactor temperature of 450 °C and a heating rate of 17 °C/min). Even though char yields were favoured at low reactor temperatures (269 – 300 °C), the higher heating values of the char were favoured at high reactor temperatures (29 – 34 MJ/kg for 375 – 481 °C). Reactor temperature had the most significant effects on product yield and quality for the respective Slow and Vacuum Pyrolysis experimental runs. The bio-oils yielded for SP and VP were found to be rich in furfural and acetic acid.
AFRIKAANSE OPSOMMING: Regerings regoor die wêreld het in die afgelope tyd toenemende fokus geplaas op skoner tegnologie en volhoubare metodes van kragopwekking in 'n poging om weg te beweeg van fossielbrandstof gebasseerde energie, wat geag word as nie volhoubaar nie en skadelik vir die omgewing. Hierdie tendens is ook ondersteun deur die Suid-Afrikaanse regering, met 'n duidelike bedoeling om die land se kragopwekking te diversifiseer deur, onder andere, biomassa as 'n hernubare bron vir die opwekking van elektrisiteit te gebruik. Houtagtige biomassa en verwante bosbou afval in die besonder, kan potensieel gebruik word as so 'n hernubare hulpbron, veral aangesien ‘n groot aantal vinnig groeiende hardehout spesies tans in Suid-Afrika verbou word. Ongeveer 6,3 miljoen ton Eucalyptus grandis word jaarliks verkoop vir pulp produksie, terwyl 'n verdere 7 miljoen ton van Eucalyptus spesies verkoop word as paal hout. Met hierdie boom spesies wat kommersiële volwassenheid bereik binne 7 - 9 jaar in die Suid-Afrikaanse klimaat, is daar werklike potensiaal vir die benutting van houtagtige biomassa as 'n hernubare energiebron. In hierdie studie is pirolise ondersoek as 'n metode om E.grandis te kondenseer en op te gradeer na energie en chemikalie ryke produkte. Die pirolise van E.grandis is die proses van termiese afbreking van die biomassa, in die afwesigheid van suurstof, om houtskool en bio-olie te produseer. Die termiese afbrekingsgedrag van E.grandis is bestudeer deur gebruik te maak van termo-gravimetriese analise (TGA) by die Karlsruhe Instituut van Tegnologie in Duitsland en daarna gebruik om die kinetiese konstantes vir die iso-omskakeling van E.grandis en sy hoof komponente te bepaal. Stadige, Vakuum en Snel pirolise is ondersoek en geoptimiseer om produk opbrengste te maksimeer en die sleutel proses veranderlikes wat die kwaliteit van die produk beïnvloed te identifiseer. Die Snel Pirolise van E.grandis is ondersoek en vergelyk op bank- (KIT0.1 kg / h), laboratorium- (SU1 kg / h) en proefaanlegskaal (KIT10 kg / h) deur gebruik te maak van Snel pirolise reaktore by die Universiteit van Stellenbosch (US) in Suid-Afrika en die Karlsruhe Instituut van Tegnologie (KIT) in Duitsland. Die Stadige en Vakuum Pirolise van E.grandis is ondersoek en vergelyk met behulp van 'n gepakte bed reaktor aan die Universiteit van Stellenbosch. Die TGA studie het openbaar dat biomassa deeltjiegrootte 'n onbeduidende uitwerking op die termiese afbrekingsgedrag van E.grandis het by 'n verhittings tempo van 50 ° C / min. Dit is ook bewys dat die verhoging van die oond verwarming tempo die termo-gravimetriese (TG) en differensiële termo-gravimetriese (DTG) kurwes na hoër temperature verskuif, terwyl dit ook die maksimum tempo van vervlugtiging laat toeneem het. Lignien het gelei tot die grootste spesifieke houtskool opbrengs en het ook oor die wydste temperatuur interval gereageer van al die monsters wat ondersoek is. Die gemiddelde aktiveringsenergieë vir die monsters wat ondersoek is, was 177,8, 141,0, 106,2 en 170,4 kJ / mol, onderskeidelik vir holosellulose, alpha-sellulose, Klason lignien en rou E.grandis. Bio-olie opbrengs is geoptimeer teen 76 wt. % (DAF) vir die SU1 kg / h Snel Pirolise aanleg met behulp van 'n gemiddelde biomassa deeltjiegrootte van 570 μm en 'n reaktor temperatuur van 470 ° C. Verskille in die onderskeie kondensasie kettings van die verskillende Snel Pirolise aanlegte wat ondersoek is, het gelei tot hoër gas- en houtskool opbrengste vir die KIT reaktor konfigurasies in vergelyking met die SU1kg/h FP plant. Verskille in die damp retensie tyd tussen Stadige (> 400 s) en Vakuum pirolise (<2 s) het gelei tot 'n hoër vloeistof en laer houtskool opbrengs vir Vakuum Pirolise. Plaaslike vloeistof opbrengs maksima van 41,1 en 64,4 wt. % (daf) is gevind vir Stadig en Vakuum pirolise onderskeidelik, bereik by 'n reaktor temperatuur van 450 ° C en 'n verhittingstempo van 17 ° C / min. Selfs al is houtskool opbrengste bevoordeel by lae reaktor temperature (269 - 300 ° C), is die hoër warmte waardes van die houtskool bevoordeel deur hoë reaktor temperature (29 - 34 MJ / kg vir 375 - 481 ° C). Reaktor temperatuur het die mees beduidende effek op die produk opbrengs en kwaliteit vir die onderskeie Stadige Pirolise en Vakuum Pirolise eksperimentele lopies gehad. Die bio-olies geproduseer tydens Stadige en Vakuum Pirolise was ryk aan furfuraal en asynsuur.
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Peacocke, George V. C. "Ablative pyrolysis of biomass". Thesis, Aston University, 1994. http://publications.aston.ac.uk/9764/.
Testo completoAbstract (sommario):
The primary objectives of this work were to design, construct, test and operate a novel ablative pyrolysis reactor and product recovery system. Other key objectives included the development of an ablative pyrolysis reactor design methodology, mathematical modelling of the ablation process and measurement of empirical ablation rate data at 500°C. The constructed reactor utilised a rotating blade approach to achieve particle ablation in a 258mm internal diameter reactor. By fulfilling the key requirements of high relative motion and high contact pressure, pine wood particles of maximum size 6.35 mm were successfully ablated. Sixteen experiments were carried out: five initial commissioning experiments were used to test the rotating blade concept and to solve char separation problems. Mass balances were obtained for the other eleven experiments with good closures. Based on ablatively pyrolysed dry wood, a maximum organic liquid yield of 65.9 wt% was achieved with corresponding yields of 12.4 wt% char, 11.5 wt% water and 9.2 wt% non-condensable gas. Reactor throughputs of 2 kg/h dry ablated wood were achieved at 600°C. The theoretical ablative pyrolysis reactor design methodology was simplified and improved based upon empirical data derived from wood rod ablation experiments. Yields of chemicals were qualitatively similar to those of other fast pyrolysis processes. The product recovery system, comprising hot char removal, liquids collection in two ice-cooled condensers followed by gas filtration and drying, gave good mass balance closures. The most significant problem was char separation and removal from the reactor. This was solved by using a nitrogen blow line. In general, the reactor and product collection systems performed well. Future development of the reactor would involve modification of the reactor feed tube to allow the reactor residence time to be reduced and testing of the rotating blade approach with different blade angles, configurations and numbers of blades. (DX185,666)
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Urban, Brook John. "Flash Pyrolysis and Fractional Pyrolysis of Oleaginous Biomass in a Fluidized-bed Reactor". University of Toledo / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1431105367.
Testo completo
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Sundberg, Elisabet. "Granskning av avancerade pyrolysprocesser med lignocellulosa som råvara – tekniska lösningar och marknadsförutsättningar". Thesis, KTH, Skolan för kemivetenskap (CHE), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-207584.
Testo completoAbstract (sommario):
När befolkningsmängden ökar och teknisk och ekonomisk utveckling sker så påverkas även energianvändningen. Detta ställer krav på att energitillförseln är säker, stabil och hållbar. I dag är det fossila bränslen som dominerar globalt sett vilket får konsekvenser för den miljö vi lever i, och dessutom är det en ändlig, ohållbar resurs. Därför behöver dessa ersättas av hållbara alternativa energikällor, vilket också är centralt för miljömål i både Sverige och i den Europeiska Unionen. Förhoppningar finns om att processer som omvandlar lignocellulosa till fasta, flytande och gasformiga drivmedel och bränslen kan bidra till omställningen från fossilt till förnybart. I detta examensarbete som utförts i samarbete med KTH och IVL Svenska Miljöinstitutet har främst en av dessa omvandlingsprocesser undersökts närmare – pyrolys. Pyrolys är en termisk process som omvandlar lignocellulosa under temperaturer mellan cirka 300-650 °C under syrefria förhållanden. Tre faser kan erhållas. En gasfas som kan kondenseras till pyrolysolja, en fast fas som benämns biokol eller kol (beroende på slutanvändning) och en okondenserbar gasfas. Utbytet av produkter och kvalitet på dessa styrs främst av: typ av råvara, typ av reaktor och av vilka processförhållanden som råder. En undersökning av olika pyrolysprocessers status på marknaden har gjorts. Graden av kommersialisering och status i nuläget och hur framtiden kan se ut för både tekniken och produkterna har uppskattats genom litteraturstudier, internetsökningar och intervjuer med utvalda företag och personer med kunskaper inom pyrolys. Rapporten visar att pyrolys inte ännu är en helt kommersiell process, men att den har möjlighet att bli det med rätt förutsättningar. Det är svårt att säga när det sker, då det förutom fortsatt teknisk utveckling, ökad kunskap kring pyrolysprocessen och resultat av demonstrationer beror på olika externa faktorer. Yttre faktorer för kommersialisering av pyrolys i Sverige har identifierats som ökad säkerhet kring politiska styrmedel och beslut kring långsiktiga sådana (osäkerhet och kortsiktiga beslut skrämmer bort investerare), vikten av att etablera en värdekedja för att säkra investeringen, och priser på fossila drivmedel och biomassa som råvara. Processer för produktion av biokol verkar dock ha hunnit längre än de för pyrolysolja och är i ett tidigt stadium av kommersialisering. Den enda tillämpningen som är fullt kommersiell idag är produktion av träkol och för detta tillämpas ofta traditionella satsvisa processer. Många möjliga användningsområden för produkterna finns där de har potential att reducera koldioxidutsläpp och bidra till en mer hållbar framtid. Standardisering och certifiering av produkter är då viktigt, samt demonstration av användning. Stabilisering och vidare förädling av pyrolysoljan är en annan viktig faktor för kommersialisering. Ännu verkar processer för katalytisk uppgradering inte vara tillräckligt tekniskt eller ekonomiskt utvecklade för att ge en konkurrenskraftig produkt, men forskning pågår kring detta. Integrering av processen ser ut att kunna öka energieffektiviteten, samt bidra till minskade produktionskostnader.The population growth as well as a rapid technical and economic development globally affects the energy consumption. This requires a secure, stable and sustainable supply of energy. Today fossil fuels dominate globally and this results in environmental problems. Fossil fuels are also a finite, unsustainable resource. Thus, there is a need to replace fossil fuels with sustainable alternative sources of energy. This is also central for environmental goals both in Sweden and in the European Union. There are expectations that processes for the conversion of lignocellulosic biomass to solid, liquid and gaseous fuels can contribute to a transition from fossil to renewable fuels. In this thesis, carried out in collaboration between KTH and IVL Swedish Environmental Research Institute, one of the conversion processes is investigated in detail – pyrolysis. Pyrolysis is a thermal process that converts lignocellulose under anaerobic conditions at temperatures between about 300-650°C. Three phases can be obtained as products. A volatile which can be condensed into pyrolysis oil, a solid which may be termed biochar or charcoal depending on the end use, and a gas phase. The yield and the quality of the products is dependent upon the type of raw material, the type of reactor and the process conditions. An examination of the status of different pyrolysis processes on or on the way to the market has been made. The current degree of commercialization and what the future may look like for both the technology and the products have been assessed through literature studies, internet searches, and interviews with selected companies and individuals with expertise in pyrolysis. This report reveals that continuous pyrolysis is not yet a fully commercial process, but that it has the opportunity to reach commercialization during the right conditions. It is difficult to say when it occurs, due to various external factors, continued technical development, increased knowledge of the pyrolysis process and results of the current demonstrations. In this report, several critical factors for the commercialization of pyrolysis in Sweden have been identified, e.g. increased stability for policy instruments and that will limit the risk for investments (uncertainty and short-term decisions frightens investors) and the establishment of a value chain for the products, i.e. a stable market. Prices on fossil fuels and biomass feedstock are also important factors. Processes for the production of biochar is in the early stages of commercialization, and seem to have reached further in their development than processes for pyrolysis oil. The only fully commercial application of pyrolysis today is the production of charcoal that commonly is performed in traditional batch-wise processes. There are many possible uses for the products in which they have the potential to reduce carbon emissions and contribute to a more sustainable future. Standardization and certification of products is important, and demonstration of the use. Stabilization and further upgrading of pyrolysis oil is another important factor for commercialization. It seems like processes for catalytic upgrading are not yet sufficiently technically or financially developed to be able to provide a competitive product. Research and development in this area are ongoing. Integration of the process with incumbent industrial processes seems to be able to offer increased energy efficiency and reduced production costs.
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MacGillivray, Tanya Frances. "Analysis of lichens under environmental stress using pyrolysis-GC-MS and pyrolysis-GC-FID". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0018/MQ54933.pdf.
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Wretborn, Tobias. "Pyrolysis of Wood Chips : Influence of Pyrolysis Conditions on Charcoal Yield and Charcoal Reactivity". Thesis, Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-179.
Testo completoAbstract (sommario):
At a steel mill, charcoal from biomass is a potential substitute to coal as a reducing agent in the Blast Furnace. The steel industry accounts for 5 % of the global CO2 emissions. Charcoal, being a renewable fuel, has the potential to mitigate the steel industry’s contribution to global warming. If charcoal were to replace the pulverized coal injected into one of Sweden´s two blast furnaces an estimated 1,13 Mton raw biomass per year would be required, this is equivalent to 2,5 % of the total available biomass in Sweden the year 2020 . If this is to be realized, a well optimized pyrolysis process for charcoal production would be required, a process with high charcoal yield that minimize the biomass consumption. This report presents a study on pyrolysis of wood chips. The two main objectives of this work have been to find pyrolysis conditions, applicable in a real process, that increase the charcoal yield and also to investigate how the reactivity of the charcoal is affected by these conditions. A hypothesis with two approaches has been proposed and evaluated experimentally. It has been proposed that the charcoal yield is increased if the tar found in the pyrolysis gases are condensed and returned to impregnate the ingoing wood before undergoing a second pyrolysis step. Or, the charcoal yield is increased by letting the tar impregnate the outgoing charcoal before the two undergoes a second pyrolysis step. The hypothesis has been evaluated in a laboratory where pyrolysis has been conducted on chips from fir wood together with bio-oil. The bio-oil has been used to resemble tar. It has been concluded that by recycling tar the charcoal yield is increased. Pyrolysis of fir wood at 340 oC yields 32 % charcoal. If the wood is impregnated before the pyrolysis with an amount of bio-oil equivalent to a tar yield of 25 % the charcoal yield is increased to 37,7 %. It is possible to say, with 80 % confidence, that pyrolysis of wood and bio-oil gives a higher charcoal yield if the two undergoes pyrolysis while being in contact with each other instead of being separated. The charcoal yield is not increased by pyrolysis of charcoal impregnated with bio-oil. There is no difference in reactivity between charcoals from impregnated wood and plain wood.
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Al, Sayegh Hassan. "Microwave pyrolysis of forestry waste". Thesis, University of Nottingham, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.576151.
Testo completoAbstract (sommario):
This thesis reports a fundamental study of the unassisted pyrolysis of wood using microwave energy for the production of bio-oils. The majority of previous work on the microwave pyrolysis of woody biomass to produce bio-oils has been performed in domestic type multimode cavity based microwaves ovens and has concluded that attaining temperatures required for pyrolysis (500°C) is not possible due to the microwave transparent nature of the material. To overcome this, many researchers have resorted to adding microwave susceptible doping agents to stimulate heating of the wood through conductive heat transfer. Although this method generates overall process effects, it does not realise the unique heating characteristics that microwave energy may offer, such as volumetric and highly selective heating. An in-depth study of the effect of temperature on the dielectric properties concluded that at room temperature, wood is a relatively good microwave absorber with a loss tangent (tan δ) of 0.20 at 2.142 GHz compared to water which has a tan δ of 0.15 under the same conditions. However, as temperature is increased, wood starts to become microwave transparent as the inherent moisture (the microwave significant material from a microwave heating point of view) evaporates causing a decrease in tan 15. Dielectric property results indicated that wood can be classified as a microwave transparent cellular matrix of cellulose, hemicellulose and lignin containing a microwave absorbing phase (water). Selective heating of the bound water before evaporation may be used to heat the remaining bulk to pyrolysis temperatures of circa. 500°C It has been demonstrated that the rate of heating has a marked effect on the microwave susceptibility of the wood above 300°C. As heating rate increases, wood remains microwave responsive up to pyrolysis temperatures of 500°C. At a heating rate of 2°C/min, tan δ was measured at 0.03 at 2.142 GHz, whilst at a heating rate of 15°C/min, tan δ increased more than six fold to 0.19 under the same conditions. A TMo1n applicator was designed and fabricated for the pyrolysis of wood, based directly upon the dielectric properties of the wood feed. This, coupled with automatic tuning to minimise reflected power and increase energy efficiency, ensured a high bulk power density of ~108 W/m3 with 1kW of microwave power compared to a domestic microwave oven which would only generate ~104 W/m3 in the wood under the same conditions. Such a high power density leads to a high heating rate which is required to overcome the decrease in tan 0 shown at lower heating rates in the earlier work. As opposed to the majority of literature, this work has categorically shown that the unassisted microwave pyrolysis of wood to produce bio-oil is technically feasible. This could lead to the full utilisation of the benefits of microwave heating and the unique heating gradients generated that may be beneficial for this process. To test the benefits microwave heating may offer, a matrix of batch pyrolysis tests was carried out to determine the effect of power density, particle size, moisture content and residence time on the yield of bio-oil, char and gas produced from pine and spruce samples. An increase in bulk power density from 1.7x107 to 7.5x107 W/m3 increased bio-oil yield from 29% to 55%. A further increase in power density had no effect on the yield of bio-oil. This body of work showed that the dimensions and geometry of the sample are important factors affecting the yields of products produced. Even though microwave energy heats volumetrically, sample cooling is still constrained to conventional heat loss models (conduction, convection and radiation). Results showed that minimising heat loss and maximising bulk power density can lead to higher bio-oil yields. It was demonstrated that as residence time increased (using a constant power of 1kW), the yield of bio-oil also increased from 13% at 90 seconds to 39% at 180 seconds. These results are the opposite to those observed from conventionally heated pyrolysis experiments as the longer residence promotes cracking of the bio-oil into incondensable gases, causing a decrease in bio-oil yield. This may lead to a potential benefit in utilising microwave heating in this process as expensive rapid quenchers need not be designed. From the particle size range tested, an optimum particle size of 25 mm was found to maximise bio-oil yield. This is much greater than the optimum particle size in conventionally heated pyrolysis (<1mm) and has major implications for the economics of scale up as projected comminution energy requirements are drastically reduced from around 800 kWhr/tonne to 50kWhr/tonne.
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Puntambekar, Shobha. "Mechanism of pyrolysis of methylchlorosilanes". Thesis, University of Leicester, 1995. http://hdl.handle.net/2381/33864.
Testo completoAbstract (sommario):
This work describes the kinetics and mechanisms of the gas phase pyrolyses of some methylchlorosilanes based on experimental and numerical integration studies. Chapter 1 introduces a brief summary of the general properties and chemistry of silicon intermediates: silylenes, silenes, disilenes and silyl radicals. Chapter 2 describes the Stirred Flow Reactor technique used for studying the gas phase pyrolyses of methylchlorosilanes. This chapter also describes numerical integration methods. Finally, a description of the experimental set up used for studying the photochemical interaction between C60 (Buckminsterfullerene) and silicon intermediates concludes this chapter. Chapters 3-7 describe gas phase pyrolyses of methylchlorosilanes complemented by numerical integration studies. It is shown in each case that thermal decomposition is initiated by a radical mechanism. Trapping experiments using toluene and buta-1,3-diene with methyldichlorosilane show formation of silyl and silylene intermediates. Kinetic experiments on methylchlorosilanes in the presence of CO2 show an increase in the rate of methane formation. Numerical integration studies show that the short lived double bonded intermediates CH2=SiX2 (X = H,Me and Cl) are important in the pyrolysis of some methylchlorosilanes. A significant finding of this work is that silylene insertion reactions play an important part in MexSiCly (x,y =1,2) pyrolyses. The findings of Chapter 3-7 are discussed together in Chapter 8. In the appendix an account of an attempted gas phase synthesis of polysilane attached to C60 (Buckminsterfullerene) is presented.
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Kreutter, William. "Kinetic Analysis of Biosolid Pyrolysis". Thesis, Marquette University, 2019. http://pqdtopen.proquest.com/#viewpdf?dispub=13857404.
Testo completoAbstract (sommario):
Waste reduction and energy recovery have been an environmental focus. Many of these solutions involve the thermal degradation of waste, such as household garbage or organic waste. To help reduce the negative environmental impact associated with processes like incineration, methods have been developed to utilize the carbonaceous material and energy contained in waste. Wastewater treatment plants are responsible for collecting and cleaning billions of gallons of sewage and stormwater each year. The water collected goes through multiple cleaning stages before being discharged into surface water. Sewage sludge, commonly referred to as biosolids, are produced during the process. Biosolids are carbon rich particles that can be used as fertilizers. The city of Milwaukee dries its biosolids and sells them as a fertilizer called Milorganite ®.
Pyrolysis is a thermochemical process which involves heating an organic material in an inert atmosphere to produce gases and a char residue. Applying pyrolysis to biosolids reduces the volume of waste to be landfilled and yields three products, including high-heating value light gases (py-gas) and a carbon rich porous char (biochar) that works well as a fertilizer, similar to dried biosolids. Pyrolysis of locally-produced dried biosolids will be studied in this thesis.
Thermogravimetric analysis (TGA) is an experimental technique used to study thermal decomposition reactions, such as pyrolysis, by measuring the mass of a sample as a function of temperature and time. In this study, non-isothermal TGA has been used to study the pyrolysis kinetics of Milorganite® . The kinetic parameters are essential for sizing reactors to optimize the pyrolysis process. Pyrolysis of dried biosolids is modeled as a combination of independent parallel reactions. Thermogravimetric (TG) and differential thermogravimetric (DTG) data were used with a nonlinear model-fitting method to determine the activation energy, pre-exponential factor, and fractional contribution for the five major pseudo-components found in the dried biosolid. In contrast with the few existing studies using model-fitting approaches for biosolid pyrolysis kinetics, this study first fits the kinetic parameters to TG data, then employs the results as initial guesses for a second fitting process to DTG data. This technique makes for a smoother convergence process in reducing the residual between fitted and experimental data. More importantly, this study performed the fitting process for a wide range of initial guesses and found that the solver converged to the same set of kinetic parameters for 95% of the initial guesses, inspiring confidence that the kinetic parameters correspond to a global, rather than a local, minimum.
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Ko, Glen H. (Glen Hong). "Pyrolysis of different coal types". Thesis, Massachusetts Institute of Technology, 1988. http://hdl.handle.net/1721.1/74804.
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Abdul, Halim Siti. "Biomass pyrolysis using microwave technology". Thesis, University of Sheffield, 2016. http://etheses.whiterose.ac.uk/17555/.
Testo completoAbstract (sommario):
A series of biomass wastes from Malaysia known as Malaysian wood pellets, and rubberwood were employed in the present work. Using these materials as the feedstock, two different heating techniques; external heating by means of conventional slow pyrolysis (SP) and volumetric heating by means of microwave pyrolysis (MP) were carried out. Two distinct temperatures; 500°C and 800°C were used. The main objective was to characterise both the microwave-pyrolysed products and slow pyrolysed products including the influence of temperature so as to compare and contrast in terms of yield, and composition of the char, oil and high-value fuel gas (H2) or syngas (H2+CO). Whilst there is an increasing interest in comparing microwave pyrolysis with conventional pyrolysis, much of the research work done in the past focussed on using domestic microwave ovens with power control features where indirect temperature measurements were carried out at different power and time settings. In the present research, the control feature for both heating techniques is similar, where the user can conveniently set the desired pyrolysis temperature and therefore, this would allow for a more direct and reliable comparison of products obtained from conventional pyrolysis and microwave pyrolysis. The research found that the use of the microwave oven system to conduct pyrolysis boosted the production of oil but reduced the total gas yield. The char proportion also reduced when microwave heating method was applied. This research also revealed that the configuration of the microwave oven with mode stirrer and bottom-fed waveguide that produces a cyclic controlled output power of 1000 W at any set temperature has yielded different results when compared to previous studies and so provides a new understanding for the microwave pyrolysis community. The results demonstrated that the microwave-pyrolysed chars were slightly more porous than slow-pyrolysed chars at 500°C. However, at a higher temperature of 800°C, lower surface area was obtained from microwave pyrolysis which can be attributed to significant damage to the char structure as the consequence of high power supplied into the cavity and high temperature used. SEM microphotographs revealed that microwave pyrolysis at 500°C led to the formation of char with clearly defined pore structure. In the case of gaseous product, both heating approaches were found to produce a comparable level of H2+CO content except those produced by MP at higher temperature (800°C). Regarding bio-oil quality, the microwave-pyrolysed oil was found to present compounds with higher aliphatic content and contain less polycyclic aromatic hydrocarbon (PAH) content, which is an added quality value as PAH is toxic to the environment. As demonstrated in the present work, employing a microwave oven to conduct pyrolysis process leads to a great time saving where the woody samples required only 8-10 minutes and 15-16 minutes to reach 500 and 800ºC respectively. On the other hand, the electric furnace used to conduct conventional pyrolysis process demonstrated a slower performance where the time required to reach 500 and 800ºC were about 49 and 72 minutes respectively. This again emphasizes that microwave oven is powerful to speed up the pyrolysis process due to the nature of rapid heating within the internal body of the sample. Additionally, from the viewpoint of energy consumption, microwave oven used approximately 62% less energy than the electric furnace to conduct pyrolysis process and therefore leads to greater energy saving. In the present work, COMSOL Multiphysics software has successfully demonstrated solutions of the numerical coupled electromagnetic and heat transfer equations. The results extracted from the simulation using specified cavity geometry, dielectric properties and thermal properties were seen to agree reasonably well with the experimental data in terms of the temperature profile and heating behaviour of the biomass. The location of hot spots and cold spots from the simulation also agreed with that observed from the experiment. The simulation work has proved that the inhomogeneity of temperature of the biomass is reflected by the local occurrence of hot spots and cold spots. These are influenced by the standing waves of different electric field concentration formed at different areas inside the cavity, and this phenomenon is very common for biomass treatment in a microwave environment. The effect of different positions of the waveguide is remarkable where the bottom-fed microwave energy oven was shown to have a poor electric field distribution. However, when simulation was done on combining the effect of having the microwave energy fed from the bottom and the presence of the mode stirrer, the electric field was greatly improved with the heating distribution of the biomass resembling that obtained from the side-fed microwaves energy oven (usually refers to a common home microwave oven). The effect of having a mode stirrer rotating inside the microwave oven is also pronounced where the mode stirrer acts to stir the electric field strength within the cavity so that a more uniform heating within the biomass can be achieved. The simulation work also demonstrated that the amount of microwave power absorbed in the biomass materials varies according to the changes in loading height of the biomass, and sample positioning inside a microwave oven also contributes to the electric field distortion and heating behaviour of the biomass. Interestingly from the simulation, for a specified microwave cavity, an optimum bed size of biomass was found at 50mm height where maximum microwaves energy absorption takes place. In this sense, more microwaves energy can be converted into heat thereby ultimately helping the biomass to reach the desired pyrolysis temperature in shorter time. The COMSOL modelling on microwave heating therefore has shown to be simple and practical for use as a framework in predicting temperature profile of the biomass and intensity of the electric field.
21
Grubbs, Harvey J. "Monomer synthesis and polymer pyrolysis". Diss., Virginia Tech, 1993. http://hdl.handle.net/10919/37897.
Testo completoAbstract (sommario):
Methods for the large scale preparation and purification of bis( 4-aminopheny 1)-1- phenyl-2,2,2-trifluoroethane (3F-diamine) and bis( 4-hydroxyphenyl)-1-phenyl-2,2,2- trifluoroethane (3F bis-phenol) have been developed. Spectroscopic characterization of by-products was used to develop a mechanistic understanding for synthetic design and to formulate purification techniques needed to produce monomer grade products. Utilizing the preparative methods represented in the present work, it was possible to obtain sufficiently pure 3F-diamine to allow the synthesis of soluble, end-capped, fully cyclized polyimides with glass transition temperatures greater than 430°C. The direct preparation of 3F bis-phenol from phenol and trifluoroacetophenone by trifluoromethanesulfonic acid catalyzed hydroxy alkylation was optimized to produce monomer grade 3F bisphenol. Previously reported methods were less direct and produced lower purity product. Current research efforts are exploring the utility of this monomer system for the preparation of novel poly(arylene ethers), polycarbonates, and polyesters. Bis(4-hydroxy-3- aminophenyI)-1-phenyl-2,2,2-trifluoroethane [3F-bis(aminophenol)] has recently been successfully prepared from 3F-phenol. Soluble, high glass transition temperature, fully-cyclized polybenzoxazoles have been obtained from 3F-bis(aminophenol).
The synthesis and characterization of polymer systems containing the phosphine oxide unit as an integral part of the backbone continue to be areas of active research. To date the majority of research activity has centered on the synthesis and features of poly(arylene ether phosphine oxide) (PEPO). All PEPOs gave significant amounts of phosphorus-containing char at temperatures where other engineering polymers are completely volatilized. This behavior was related to the superior self-extinguishing behavior of all the phosphorus containing systems. A detailed pyrolytic degradation study of the phosphorus containing PEPO system was carried out. The study utilized analytical techniques such as pyrolysis-gas chromatography-mass spectroscopy and neutron activation analysis.
To continue the exploration of the phosphine oxide systems, the synthesis and characterization of a novel phosphorus containing diamine, bis( 4-amino-phenyl) phenylphosphine oxide, has been completed. Further research is in progress preparing phosphine oxide based polyimides from this diamine. Synthesis of bis(4-hydroxyphenyl)phenylphosphine oxide and additional phosphine oxide intermediates are also reported.Ph. D.
22
Mate, Marc. "Numerical Modelling of Wood Pyrolysis". Thesis, KTH, Skolan för kemivetenskap (CHE), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-206852.
Testo completoAbstract (sommario):
In this project, a numerical model describing the reaction mechanism and the mass and energy transport in wood pyrolysis is studied. The applicability of the model in predicting actual biomass pyrolysis assessed by comparing the model to TGA experimental measurements. The comparison to experiments is done in relation to the mass loss characteristics of chips of varying sizes. The mass loss is of interest as it is a variable necessary in the coupling of reactor and particle models. Three reaction models were simulated and results compared to experimental data, namely, the reaction model developed by Park et al. [Combustion and Flame 157 (2010) 481-494], a simple multicomponent parallel reaction model, and a competitive reaction model. The model of Park et al. did not fit with the experimental data as it underestimates the char yield. The parallel reaction model, which is based on hemicellulose and cellulose decomposition to char and volatiles, also did not agree with the experiments even when fitting the parameters to the data. The downward trend of char yield with increasing temperature suggests there exists competition between the volatiles and char in wood pyrolysis. The proposed competitive reaction model which consists of a hemicellulose reaction to volatiles and a cellulose reaction to volatiles and char is in good agreement with the experimental data. The mass loss characteristics in the experimental temperature range is fairly predicted within reasonable accuracy.
23
Poolasap, Naowarat. "Analytical Pyrolysis of Thai Lignites". TopSCHOLAR®, 1985. https://digitalcommons.wku.edu/theses/2729.
Testo completoAbstract (sommario):
Samples of four different Thai lignites were utilized to study the effects of ceiling temperature and heating rate on the overall yield and product distribution by the technique of analytical pyrolysis (pyrolysis-gas chromatography). Ceiling temperatures of 450°, 550°, 650°, 750°, 850°, and 950°C, a heating rate of 500°C/sec and pyrolysis intervals of 20 seconds were investigated. The results were reported in terms of percentage high-volatile product and low-volatile product fraction, weight-loss (% by weight), and total yield (counts per milligram). One sample which showed the highest sensitivity to changing ceiling temperature was selected to study the effect of heating rate on overall yield and product distribution. Heating rates of 500°C/sec and 100°C/sec (for an interval of 20 seconds) and 500°C/sec for one minute and 300°C/min for two minutes were employed in the study, at a ceiling temperature of 750°C.
The results of the above investigation may be summarized as follows:
All four samples are lignite A (rank) but give different pyrograms as a result of differences in maceral concentrations and chemical structure of each of the coals.
The total yield, high-volatile product, and weight-loss increase with increasing ceiling temperatures.
Heating rates in the range studied have no significant effect on the total yield and product distribution.
High -volatile product yield increases with increasing pyrolysis interval because of secondary cracking reactions but the overall product yield remains essentially constant.
24
Hasan, MD Mahmudul. "Pyrolysis characteristics of mallee biomass". Thesis, Curtin University, 2015. http://hdl.handle.net/20.500.11937/2508.
Testo completoAbstract (sommario):
The overall technical feasibility of a novel grinding pyrolysis technology has been demonstrated at a pilot plant scale. The pyrolysis behaviour of mallee biomass was investigated in this pilot plant under a wide range of experimental conditions. Further experiments were also carried out by pyrolysing single mallee wood cylinders in a fluidised sand bed. The data from this study provide essential information for the commercialisation of this novel grinding pyrolysis technology.
25
Östman, Marcus, e Elin Näsström. "Construction of a Labview controlled pyrolysis unit for coupling to a Pyrola 85 pyrolysis chamber". Thesis, Umeå universitet, Kemiska institutionen, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-56549.
Testo completoAbstract (sommario):
Pyrolysis is the process of molecular decomposition in an inert environment using heat. It is possible to fragment large molecules, such as polymers, by pyrolysis and separate the fragments directly in a GC. This makes it possible to form complex sample fingerprints that can be used in various applications, for example in forensic science. In this project, a malfunctioning Pyrola 85 pyrolysis unit was fixed by measuring the voltage signals from the photo diode during pyrolysis in a Labview program. With the Labview program, a partly manual filament temperature calibration procedure was developed, as replacement for the non-working automatic calibration procedure. The functioning pyrolysis unit was then installed on a GC/MS in the National University of Science, Ho Chi Minh City, Vietnam. Plant samples were analysed with the Pyrolysis-GC/MS system as a test of the system, resulting in pyrograms with a few identifiable peaks. However, both pyrolysis and GC/MS settings needs further investigation to optimize the analysis. In Sweden, a Labview controlled Pyrolysis unit was constructed to investigate the possibility of improving certain functions of the original control unit. A proposed Labview program and circuit boards were constructed and partially evaluated. The accuracy and precision of the pulses from the Labview program was
26
Goteti, Anil Chaitanya. "Experimental investigation and systems modeling of fractional catalytic pyrolysis of pine". Thesis, Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/42844.
Testo completoAbstract (sommario):
The fractional catalytic pyrolysis of pine was studied both experimentally and through models. A preliminary stage economic analysis was conducted for a wood chip pyrolysis facility operating at a feed rate of 2000 wet ton/day for producing bio-oil.
In the experimental study, multiple grams of bio oil were produced in a single run to facilitate the more extensive characterization of the oil produced from pyrolysis of biomass impregnated with different catalysts. Two reactors configurations, a screw extruder and a tubular pyrolysis reactor, were explored to perform fractional catalytic pyrolysis of biomass. The main aim of performing a wood pyrolysis reaction in a modified screw extruder is to facilitate the simultaneous collection of bio-oil produced from staged temperature pyrolysis of three main components of wood, cellulose, hemicellulose and lignin, at a reasonable scale. Apart from complete characterization of bio-oil, this will enable us to study the effect of various selected catalysts on the quality of bio-oil and the percentage of char produced, and the influence of process parameters on chemical composition of the pyrolysis oils. These experiments were later performed in a tubular pyrolysis reactor due to the difficulty of making different parts of the extruder work well together. The goal of these experiments is to produce bio-oil in multiple grams from fractional catalytic pyrolysis of wood. This will enable us to study the effect of catalyst on the chemical composition of the oil and percentage of char produced.
In the modeling studies, a model of an auger reactor comprised of three different zones run at different temperatures to facilitate the collection of oil from pyrolysis of three major components of wood, namely cellulose, hemicelluloses and lignin, was developed. The effect of residence time distribution (RTD), and zone temperatures based on kinetic models on the yield of products was studied. Sensitivity of the Arrhenius rate constants calculated from synthetic data with respect to small variations in process parameters was evaluated.
In the economic analysis of a wood chip pyrolysis facility, mass and energy calculations were performed based on a feed rate of 2000 wet tons/day of wood chips to the dryer. The cost of bio-oil at 10% return on investment was proposed and the sensitivity of the selling price of bio-oil with respect to capital and operating costs was analyzed.
The experimental study will serve as a benchmark in exploring the above mentioned reactor configurations further. Alkali metal carbonates were used to study the quality of oil produced from pine pyrolysis. It was established that these catalysts, when added in the same molar ratio basis, increase the percentage of char. However, complete characterization of these oils for different catalysts needs to be done.
Systems modeling of pyrolysis in an auger reactor established that the kinetic parameters (depending on experimental set up) and the RTD (Residence Time Distribution) parameters play a crucial role in determining the yield of oil. Variations in temperature of zone 3 play a crucial role in varying the output of oil whereas variations in temperatures of zones 2 and 1 do not significantly impact the output of oil. For a given reaction kinetic scheme for the pyrolysis reactions, calculated values of the kinetic rate constants are not sensitive to errors in experimental conditions. It was also established that the experimental error in calculation of the RTD parameters can induce error in calculation of the Arrhenius constants but these values can still predict the yield of products accurately.
In the economic analysis of wood chip pyrolysis, the selling price of the bio-oil according to the cost calculation is projected to be $1.49/gal. The production cost of bio-oil is $ 1.20/gal. The cost of bio-oil is extremely sensitive to variations in operating cost (for example, cost of feed stock and selling price of char) and is not significantly affected by the variations in capital cost.
27
Ducatel, Estelle. "Composting of ethane pyrolysis quench sludge". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0017/MQ48061.pdf.
Testo completo
28
Gairns, Stuart Alan. "Fast pyrolysis of kraft black liquor". Thesis, McGill University, 1993. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=69795.
Testo completoAbstract (sommario):
The pyrolysis of kraft black liquor droplets under inert, reducing, and gasifying atmospheres was investigated at temperatures of 500 to 900$ sp circ$C in a well characterized single droplet tube furnace coupled to a fast-response quadrapole mass spectrometer. In addition, the behaviour of sodium during the pyrolysis of black liquor and the presence of adsorbed elemental sodium in pyrolysis char were investigated.Using the single droplet apparatus and the procedures developed, true gas formation rate data were determined under conditions simulating those in kraft recovery processes. The mass spectrometer allowed the formation rates of several compounds to be determined simultaneously. All major permanent, hydrocarbon, and sulphurous pyrolysis gases, with the exception of H$ sb2$, were determined, along with pyrolysis char and tar yields.
The rate data reveal that sulphurous gas formation occurs relatively early as compared to that of the other gases determined. The data also reveal that pyrolysis gases are formed during droplet drying. While CH$ sb3$SH and CH$ sb3$SCH$ sb3$ yields decrease sharply with temperature, and those of H$ sb2$S and CH$ sb2$SSCH$ sb3$ remain quite constant, the CS$ sb2$ formation increases to a significant level at 900$ sp circ$C. The yields of ethane and methanol also decrease sharply with temperature, but those for ethylene, methane, CO, and CO$ sb2$ correspondingly increase. Acetylene yields become measurable at 900$ sp circ$C. While the influence of gas atmosphere on the sulphur release during pyrolysis is small, the influence on hydrocarbon gas yields is significant.
The presence of adsorbed elemental sodium in black liquor pyrolysis chars was found to be responsible for the pyrophoric nature of some chars. This reduced sodium reacts with water to produce hydrogen. In a recovery boiler, sufficient hydrogen could be formed to produce an explosive mixture above the char bed, which upon detonation could trigger a smelt-water explosion. (Abstract shortened by UMI.)
29
Gao, Feng. "Pyrolysis of Waste Plastics into Fuels". Thesis, University of Canterbury. Chemical and Process Engineering, 2010. http://hdl.handle.net/10092/4303.
Testo completoAbstract (sommario):
Waste plastic disposal and excessive use of fossil fuels have caused environment
concerns in the world. Both plastics and petroleum derived fuels are hydrocarbons that
contain the elements of carbon and hydrogen. The difference between them is that
plastic molecules have longer carbon chains than those in LPG, petrol, and diesel fuels.
Therefore, it is possible to convert waste plastic into fuels.
The main objectives of this study were to understand and optimize the processes of
plastic pyrolysis for maximizing the diesel range products, and to design a continuous
pyrolysis apparatus as a semi-scale commercial plant. Pyrolysis of polyethylene (PE),
polypropylene (PP), and polystyrene (PS) has been investigated both theoretically and
experimentally in a lab-scale pyrolysis reactor. The key factors have been investigated
and identified. The cracking temperature for PE and PP in the pyrolysis is at 450 ºC, but
that of PS is lower, at 320 ºC. High reaction temperature and heating rate can
significantly promote the production of light hydrocarbons. Long residence time also
favours the yield of the light hydrocarbon products. The effects of other factors like type
of reactor, catalyst, pressure and reflux rate have also been investigated in the literature
review.
From the literature review, the pyrolysis reaction consists of three progressive steps:
initiation, propagation, and termination. Initiation reaction cracks the large polymer
molecules into free radicals. The free radicals and the molecular species can be further
cracked into smaller radicals and molecules during the propagation reactions. β-scission
is the dominant reaction in the PE propagation reactions. At last, the radicals will
combine together into stable molecules, which are termination reactions. There are three
types of cracking of the polymers: random cracking, chain strip cracking, and end chain
cracking. The major cracking on the polymer molecular backbone is random cracking.
Some cracking occurs at the ends of the molecules or the free radicals, which is end
chain cracking. Some polymers have reactive functional side group on their molecular
backbones. The functional groups will break off the backbone, which is chain strip
cracking. Chain strip cracking is the dominant cracking reaction during polystyrene
pyrolysis. The reaction kinetics was investigated in this study. The activation energy
and the energy requirement for the pyrolysis are dependent on the reaction process and
the distribution of the final products. Following the equations from other literatures, the
theoretical energy requirement for pyrolyze 1kg PE is 1.047 MJ. The estimated calorific
value of the products is about 43.3 MJ/kg. Therefore, the energy profit is very high for
this process.
The PE pyrolysis products are mainly 1-alkenes, n-alkanes, and α, ω-dialkenes ranging
from C1 to C45+. The 1-alkenes and the n-alkanes were identified with a special method
developed in this research. It was found that secondary cracking process has a
significant influence on the distribution of the product. This process converts heavy
hydrocarbons into gas or light liquid product and significantly reduces 1-alkenes and α,
ω-dialkenes. This secondary process can be controlled by adjusting the reflux rate of the
primary product. The product of PE pyrolysis with maximized diesel range output
consist of 18.3% non-condensable gases, 81.7% w/w liquid product, and less than 1%
pure carbon under high reflux rate process. Some zeolite catalysts were tested to reduce
the heavy molecular weight wax. It was found that NKC-5 (ZSM-5) was the most
effective catalyst among zeolites tested. The proportion of the non-condensable gases
was promoted from 17% w/w to 58% w/w by adding 10% w/w NKC-5 into the PE
feedstock.
The products of PP pyrolysis are mainly methyl- oligomers. The reflux effect on the
product from pyrolysis of PP is not as great as that on PE. The PP pyrolysis product
with high reflux rate consists of 15.7% non-condensable gases, 84.2% condensed liquid
product, and less than 0.25% char. Cyclohexane is the dominant component, 21%w/w
in the liquid product. 44%v/v of the non-condensable gases is propene.
In the pyrolysis product of PS, there are 4% non-condensable gases, 93% liquid, and 3%
char. Styrene accounts for 68.59%w/w in the PS liquid pyrolysis products due to the
chain strip reactions. There was 19% v/v hydrogen in the gas product, which did not
exist in the PE pyrolysis gas product. The composition of the char is almost pure
carbon, which is similar to that from PE pyrolysis.
The mixture of virgin and post-consumer PE, PP and PS have also been investigated to
identify the feedstock interaction and the effect of the contamination on the product.
The interaction promotes the production of non-condensable gases. However, the effect
of the interaction on the distribution of total product is not significant. Contamination of
paper labels on the post-consumer plastics may result in higher solid residue in the
product but no significant effect on the product was found in this study.
Based on the achievements, a continuous semi-scale reactor has been designed and
constructed at maximum capacity of 27.11kg/hr in this research. From the experiments
of pyrolysis of both virgin PE and post-consumer PE on this semi-scale pyrolysis
reactor, it was found that the major components are 1-alkenes, n-alkanes, and α, ω-
dialkenes. The distribution of the condensed products of PE pyrolysis from the semiscale
reactor is the same as that of the products from low reflux rate process with the
lab-scale reactor. However, the proportion of non-condensable gases is much higher
than that from pyrolysis in the lab-scale tests with low reflux rate because the semiscale
plant has higher reaction temperature and heating rate. Lower proportion of
unsaturated hydrocarbons was found in the condensed product from the post-consumer
PE pyrolysis than in the virgin PE product because of the contamination on the postconsumer
PE. The actual energy consumption for cracking and vaporizing PE into fuels
is 1.328 MJ/kg which is less than 3% of the calorific value of the pyrolysis products.
Therefore, the pyrolysis technology has very high energy profit, 42.3 MJ/kg PE, and is
environmental-friendly. The oil produced has very high quality and close to the
commercial petroleum derived liquid fuels. The experience of design and operation of
the semi-scale plant will be helpful for building a commercial scale plant in the future.
30
Bal, Nicolas. "Uncertainty and complexity in pyrolysis modelling". Thesis, University of Edinburgh, 2012. http://hdl.handle.net/1842/6511.
Testo completoAbstract (sommario):
The use of numerical tools in fire safety engineering became usual nowadays and this tendency is expected to increase with the evolution of performance based design. Despite the constant development of fire modelling tools, the current state of the art is still not capable of predicting accurately solid ignition, flame spread or fire growth rate from first principles. The condensed phase, which plays an important role in these phenomena, has been a large research area since few decades, resulting in an improvement of its global understanding and in the development of numerical pyrolysis models including a large number of physical and chemical mechanisms. This growth of complexity in the models has been justified by the implicit assumption that models with a higher number of mechanisms should be more accurate. However, as direct consequence, the number of parameters required to perform a simulation increased significantly. The problem is when the uncertainty in the input parameters accumulates in the model output beyond a certain level. The global error induced by the parameters uncertainty balances the improvements obtained with the incorporation of new mechanisms, leading to the existence of an optimum of model complexity. While one of the first modelling tasks is to select the appropriate model to represent a physical phenomenon, this step is often subjective, and detailed justifications of the inclusion or exclusion of the different mechanisms are infrequent. The issue of how determining the most beneficial level of model complexity is becoming a major concern and this work presents a methodology to estimate the affordable level of complexity for polymer pyrolysis modelling prior ignition. The study is performed using PolyMethylMethAcrylate (PMMA) which is a reference material in fire dynamics due to the large number of studies available on its pyrolysis behaviour. The methodology employed is based on a combination of sensitivity and uncertainty analyses. In the first chapter, the minimum level of complexity required to explain the delay times to ignition of black PMMA samples at high heat flux levels is obtained by exploring one by one the effect on the condensed phase of several mechanisms. It is found that the experimental results cannot be explained without considering the in-depth radiation absorption mechanism. In the second chapter, a large literature review of the variability associated with the main parameters encountered in pyrolysis models is performed in order to establish the current level of confidence associated with the predictions using simple uncertainty analyses. In the third chapter, a detailed analysis of the governing parameters (parametric sensitivity) is performed on the model obtained in chapter 1 to predict the delay time to ignition. Using the ranges obtained in chapter 2 for the input parameters, a detailed uncertainty analysis is performed revealing a large spread of the numerical predictions outside the experimental uncertainty. While several parameters, including the attenuation coefficient (from the in-depth radiation absorption mechanism), present large sensitivity, only a few are responsible for the large spread observed. The parameter uncertainty is shown as the limiting step in the prediction of solid ignition. In the fourth chapter, a new methodology is developed in order to investigate the predominant mechanisms for the prediction of the transient pyrolysis behaviour of clear PMMA (no ignition). This approach, which corresponds to a mechanism sensitivity, consists of applying step-by-step assumptions to the most complex model used in the literature to model non-charring polymer pyrolysis behaviour. This study reveals the relatively high importance of the heat transfer mechanisms, including the process of in-depth radiation. In the fifth chapter, an investigation of the uncertainty related to the calibration of pyrolysis models by inverse modelling is performed using several levels of model complexity. Inverse modelling couples the experimental data to the model equations and this dependency is often ignored. Varying the model complexity, this study reveals the presence of compensation effects between the different mechanisms. The phenomenon grows in importance with model complexity leading to unrealistic values for the calibrated parameters. From the performed sensitivity and uncertainty analyses, the mechanism of in-depth absorption appeared critical for some applications. In the sixth chapter, an experimental investigation on specific conditions impacting the sensitivity of this mechanism shows its large dependency on the heat source emission wavelength when comparing the two heat sources of the most used pyrolysis test apparatuses in fire safety engineering. More fundamental investigations presented in the seventh chapter enabled to quantify this dependency that needs to be considered for modelling or experimental analyses. The impact of the heat source on the radiation absorption (depth and magnitude) is shown to be predictable thanks to the detailed measurements of the attenuation coefficient of PMMA and the emissive power of the heat sources. The global uncertainty associated with the input parameters, extracted either from independent studies or by inverse modelling, appears as a limiting step in the improvement of pyrolysis modelling when a high level of complexity is implemented. A combination of numerical (sensitivity and uncertainty) analyses and experimental studies is required before increasing the level of complexity of a pyrolysis model.
31
Jones, Nicola. "The pyrolysis of composite plastic waste". Thesis, University of Leeds, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.396746.
Testo completo
32
Barker, S. J. "Nitrogen heterocycles by flash vacuum pyrolysis". Thesis, University of Liverpool, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.383390.
Testo completo
33
Fong, William Shan-chen. "Plasticity and agglomeration in coal pyrolysis". Thesis, Massachusetts Institute of Technology, 1986. http://hdl.handle.net/1721.1/74963.
Testo completoAbstract (sommario):
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 1986.MICROFICHE COPY AVAILABLE IN ARCHIVES AND SCIENCE.
Bibliography: leaves 202-205.
by William Shan-chen Fong.
Ph.D.
34
Ludlow-Palafox, Carlos. "Microwave induced pyrolysis of plastic wastes". Thesis, University of Cambridge, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.620655.
Testo completo
35
Nicolson, Iain Sinclair. "Catalytic pyrolysis of nitro aromatic compounds". Thesis, University of Edinburgh, 2003. http://hdl.handle.net/1842/15526.
Testo completoAbstract (sommario):
The work contained in this thesis was intended to study the rearrangement of o-nitrotoluene to anthranil which has previously been shown to occur under a variety of conditions. Flash Vacuum Pyrolysis (FVP) of nitrotoluene over zeolite 13X was carried out. o-Nitrotoluene was found to give conversion to toluene in 5.5% yield with recovery of starting material (12%). FVP of m-nitrotoluene gave recovery of toluene in 8% yield and starting material (7%). FVP of p-nitrotoluene gave only a trace of toluene with mainly recovery of unreacted starting material (12%). FVP of 1-ethyl-2-nitrobenzene over zeolite 13X gave conversion to ethylbenzene in 13% yield and styrene in 4% yield along with recovery of a trace of starting material. FVP of nitrotoluene was also carried out over the zeolites A, Y, ZSM-5 and mordenite as well as alumina and silica. o-Nitrotoluene was found to give conversion to aniline by a combined reduction and dealkylation in yields from 5-41% with unreacted starting material (0-515); o-toluidine and toluene were identified as minor products in several of the pyrolyses. m-Nitrotoluene over alumina gave aniline and m-toluidine. p-Nitrotoluene over zeolite Y alumina gave conversion to aniline and p-toluidine. FVP of 1-ethyl-2-nitrobenzene over these zeolites, silica and alumina gave conversion to aniline and indole in varying amounts; minor products of styrene, 2-vinylaniline and ethylaniline were also observed. FVP of 3-methylanthranil with no catalyst at 700°C gave conversion to 1H-indol-3(2H)-one in 86% yield. FVP of 3-methylanthranil over zeolite mordenite at 500°C gave conversion to 1H-indol-2(2H)-one in 11% yield along with unreacted starting material (6%). FVP of 1H-indol-3(2H)-one over zeolite mordenite at 500°C gave rearrangement to 1H-indol-2(2H)-one in 37% yield. FVP of anthranil over zeolite Y at 500°C gave conversion to aniline in 28% yield.
36
Somsri, Surapat. "Upgrading of Waste Tire Pyrolysis Oil". Thesis, KTH, Skolan för kemi, bioteknologi och hälsa (CBH), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-228358.
Testo completoAbstract (sommario):
The annual increase in waste car tires in addition to the enormous amount at present poses a major waste management problem as well as an environmental hazard. However, pyrolysis is emerging as a solution for waste tire management and a viable technology for material recycling and energy recovery that produces high energy liquid and gas products as well as char. The pyrolysis oil that is produced from this technology has the potential to be used as vehicle fuel but contains exceeding levels of sulfur and other impurities. This study investigates the upgrading and desulfurization of waste tire pyrolysis oil by reactive adsorption using a molybdenum modified zeolite and its desilicated form. The experiments were performed at 320 °C and a LHSV of 45-50 h-1 for approximately 45 min, and revealed that both desilication and Mo-modification resulted in the cracking of both gaseous and liquids compounds, reduction of TAN, denitrogenation, and deoxygenation. Desilication increased desulfurization while Mo-modification increased the EHI. The treatment was the most effective in the removal of oxygen, followed by nitrogen and sulfur. In conclusion, the treatment process is promising as a method for direct liquid upgrading but requires further research.
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Klug, Michael. "Pyrolysis -- a process to "melt" biomass". Revista de Química, 2013. http://repositorio.pucp.edu.pe/index/handle/123456789/101157.
Testo completoAbstract (sommario):
La pirolisis es un proceso termoquímico que ocurre en ausencia de oxígeno. El proceso de pirolisis tiene tres etapas: la dosificación y alimentación de la materia prima, la transformación de la masa orgánica y, finalmente, la obtención y separación de los productos (coque, aceite y gas). La planta piloto de la PUCP puede producir un biocombustible de segunda generación a partir de desechos orgánicos lo que responde al reto de un desarrollo sostenible de bioenergía en Perú.Pyrolysis is a thermochemical process that occurs in absence of oxygen. The pyrolysis process has three stages: feeding and dosing of raw materials, transformation of the organic mass and, finally, collection and separation of the products (coke, oil and gas). The pilot plant of the PUCP can produce second generation biofuels from organic waste and this responds to the challenge of a sustainable developmentof bioenergy in Peru.
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Lee, King Lung. "Design of waste tyre pyrolysis process /". View abstract or full-text, 2009. http://library.ust.hk/cgi/db/thesis.pl?CBME%202009%20LEEK.
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Adam, Mohamed A. B. "Understanding microwave pyrolysis of biomass materials". Thesis, University of Nottingham, 2017. http://eprints.nottingham.ac.uk/41301/.
Testo completoAbstract (sommario):
Global challenges related to energy security, resource sustainability and the environmental impacts of burning fossil fuels have led to an increasing need for switching to the use of clean and sustainable resources. Bio-oil produced through pyrolysis has been suggested as one of the sustainable alternatives to fossil resources for power generation as well as chemicals and biofuels production. Pyrolysis is a thermochemical process during which the biomass feedstock is heated in an inert atmosphere to produce gas, liquid (bio-oil) and solid (char) products. Microwave heating has been considered a promising technique for providing the energy required for biomass pyrolysis due to its volumetric and selective heating nature which allows for rapid heating in a cold environment. This helps to preserve the product quality by limiting secondary reactions. The aim of this research was to study the interactions between biomass materials and microwave energy during pyrolysis, and to develop a reliable and scalable microwave pyrolysis process. The dielectric properties of selected biomass materials were studied and found to vary significantly with temperature due to the physical and structural changes happening during pyrolysis. The loss factor of the biomass materials was found to reach a minimum value in the range between 300 oC and 400 oC followed by a sharp increase caused by the char formation. A microwave fluidised bed process was introduced as an attempt to overcome the challenges facing the scaling-up of microwave pyrolysis. The concept of microwave pyrolysis in a fluidised bed process was examined for the first time in this thesis. A systematic approach was followed for the process design taking into account the pyrolysis reaction requirements, the microwave-material interactions and the fluidisation behaviour of the biomass particles. The steps of the process design involved studying the fluidisation behaviour of selected biomass materials, theoretical analysis of the heat transfer in the fluidised bed, and electromagnetic simulations to support the cavity design. The developed process was built, and batch pyrolysis experiments were carried out to assess the yield and quality of the product as well as the energy requirement. Around 60 % to 70 % solid pyrolysed was achieved with 3.5 kJ·g-1 to 4.2 kJ·g-1 energy input. The developed microwave fluidised bed process has shown an ability to overcome many of the challenges associated with microwave pyrolysis of biomass including improvement in heating uniformity and ability to control the solid deposition in the process, placing it as a viable candidate for scaling-up. However, it was found to have some weaknesses including its limitations with regards to the size and shape of the biomass feed. Microwave pyrolysis of biomass submerged in a hydrocarbon liquid was introduced for the first time in this thesis as a potential alternative to overcome some of the limitations of the gas-based fluidised bed process. Batch pyrolysis experiments of wood blocks submerged in different hydrocarbon liquids showed that up 50 % solid pyrolysis could be achieved with only 1.9 kJ·g-1 energy input. It was found that the overall degree of pyrolysis obtained in the liquid system is lower than that obtained from the fluidised bed system. This was attributed to the large temperature gradient between the centre of the biomass particle/block and its surface in the liquid system leaving a considerable fraction of the outer layer of the block unpyrolysed. It was shown that the proposed liquid system was able to overcome many of the limitations of the gas-based systems.
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Abbas, Husam. "Comparative analysis of different pyrolysis techniques by using kraft lignin : Jämförelse mellan olika pyrolys metoder". Thesis, Karlstads universitet, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-78871.
Testo completoAbstract (sommario):
This thesis presents a comparison analysis between various pyrolysis techniques performed on kraft lignin. Numerous literature studies of pyrolysis techniques performed on kraft lignin are reviewed and analysed where different operation temperatures, catalysts and different heating methods are used to pyrolyze kraft lignin. Based on the collected data from the reviewed literature, calculations are performed to determine energy efficiency of each pyrolysis technique. The energy efficiencies are used to establish a comparison between various pyrolysis techniques. Energy efficiencies of all pyrolysis techniques are determined by using series of equations. Dissimilarities of products composition are investigated between various pyrolysis techniques. Environmental impacts caused by lignin pyrolysis are reviewed and discussed. Uses of products produced from lignin pyrolysis are discussed to highlight the potential of using lignin as an energy resource to produce biooil, biochar and non-condensable gases (NCG). Results show that energy efficiencies differ significantly between various pyrolysis techniques, where microwave-assisted pyrolysis (MAP) shows the highest energy efficiency. Products produced from pyrolysis show a wide range of uses in many industrial applications. Lignin based products have the potential to replace many petroleum-based products which may contribute significantly to decrease pollutants in nature and gas emissions caused by combusting fossil fuels.
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Glasier, Greg F. "Molecular growth, aerosol formation and pyrolytic carbon deposition during the pyrolysis of ethane at high conversion". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape3/PQDD_0034/NQ66664.pdf.
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Castelbuono, Joseph. "THE IDENTIFICATION OF IGNITABLE LIQUIDS IN THE PRESENCE OF PYROLYSIS PRODUCTS: GENERATION OF A PYROLYSIS PRODUCT DATABASE". Master's thesis, Orlando, Fla. : University of Central Florida, 2008. http://purl.fcla.edu/fcla/etd/CFE0002429.
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Glauber, Samuel Melville. "Design and commissioning of a continuous isothermal fast pyrolysis reactor". Thesis, Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/47544.
Testo completoAbstract (sommario):
In order to meet growing demands for alternatives to fossil fuels, biomass pyrolysis is
a method that has been explored in depth as a method to develop new liquid fuels. Fast
pyrolysis is a subtype of pyrolysis reaction in which a specimen is heated at rates in
excess of 10C/s in an oxygen-free environment, causing the specimen to thermally
degrade and release a volatile bio-oil. The goal of this thesis is to design and commission
a novel reactor for the continuous isothermal fast pyrolysis of ground biomass. The
reactor design utilizes a vibrating plate heated to a set pyrolysis temperature. Analytical
and empirically-derived vibratory transport models are presented for ground Pinus taeda
(loblolly pine) to assist in setting the desired pyrolysis reaction time. A condenser system
was designed to rapidly evacuate and chill the volatiles to prevent tar formation and
secondary reactions. Commissioning tests were run at a pair of temperatures and biomass
residence times to determine the degree of agreement between the reactor yields and
two-component volatile formation data derived from batch fast pyrolysis of Pinus taeda.
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Svanberg, Rikard. "Ex-situ Ion Enhanced Pyrolysis of Biomass : Effects of low power high voltage spark on the pyrolysis products". Thesis, KTH, Energi- och ugnsteknik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-215935.
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Gade, Prabhavathi. "Investigation of Volatile Products from Wood Pyrolysis". TopSCHOLAR®, 2010. http://digitalcommons.wku.edu/theses/1076.
Testo completoAbstract (sommario):
In this research we are following the thermo-chemical degradation of wood in the absence of oxygen. The objectives are to evaluate the influence of heating rates on pyrolysis products obtained from wood pyrolysis and to evaluate the influence of acid pre-treatment on pyrolysis products. Depending on the wood heating rates, pyrolysis can be categorized as Flash pyrolysis, Fast pyrolysis, and Slow pyrolysis. We have evaluated the volatile products obtained at different heating rates and the volatile products obtained from sulfuric acid pre-treatment by using gas chromatography- mass spectrometry (GC-MS). We have also performed thermo-gravimetric analysis (TGA) of raw wood samples and sulfuric acid pre-treated wood samples of Yellow Pine to determine the changes in weight in relation to change in temperature.
Our results indicated that by using the Flash, Fast, and Slow heating rates, the overall volatile products obtained from wood pyrolysis (i.e. the overall list of all the compounds obtained from different temperature ranges in wood pyrolysis by using different heating rates) were the same, but the volatile products obtained at different temperature ranges like Room temperature-300°C, 300°C - 400°C, and 400°C -500°C in Flash, Fast, and Slow pyrolysis were different. Most of the volatile products obtained from the pyrolysis of untreated wood were phenols. Our results also indicated that the pretreatment of wood with sulfuric acid alters the charcoal properties and releases gaseous products including furan derivatives that are useful as fuels or fuel additives. The sulfuric acid (10%) pretreatment of wood followed by slow pyrolysis produced maximum yield of charcoal, indicated by the lowest mass % decrease of 58.234. The production of furan derivatives increased by using sulfuric acid pre-treatment, which is a good improvement for the production of Furanics, the furan based biofuels. The furan based biofuels are of increasing research interest because of their significant advantages over the first generation biofuels. The thermogravimetric analysis (TGA) results indicated that the acid pre-treatment altered the decomposition rate of pyrolysis and lowered the onset of temperature for decomposition.
The use of thermal degradation of plants for creating chemicals and fuels is seeing renewed interest across the globe as it is considered carbon-neutral and it uses a renewable feedstock. The information obtained from this research work will also be valued by industries, such as charcoal and activated carbon producers, which currently perform biomass pyrolysis, by allowing them to form approaches that optimize their energy use and minimize waste.
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Miranda, Rosa. "Vacuum pyrolysis of PVC and commingled plastics". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape3/PQDD_0022/NQ52251.pdf.
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Connolly, T. Sean. "CO2 Pyrolysis and Gasification of Kraft Black". Fogler Library, University of Maine, 2006. http://www.library.umaine.edu/theses/pdf/ConnollyTS2006.pdf.
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Mahfud, Farchad Husein. "Exploratory studies on fast pyrolysis oil upgrading". [S.l. : Groningen : s.n. ; University Library of Groningen] [Host], 2007. http://irs.ub.rug.nl/ppn/30498132X.
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Mohr, David Larry. "Pretreatment and pyrolysis of polyorganosilazane preceramic binders". Diss., Georgia Institute of Technology, 1992. http://hdl.handle.net/1853/8626.
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Li, Jian 1957. "Pyrolysis and CO2 gasification of black liquor". Thesis, McGill University, 1986. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=65338.
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