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Chodak, Jillian. "Pyrolysis and Hydrodynamics of Fluidized Bed Media." Thesis, Virginia Tech, 2010. http://hdl.handle.net/10919/32920.
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Interest in non-traditional fuel sources, carbon dioxide sequestration, and cleaner combustion has brought attention on gasification to supplement fossil fueled energy, particularly by a fluidized bed. Developing tools and methods to predict operation and performance of gasifiers will lead to more efficient gasifier designs. This research investigates bed fluidization and particle decomposition for fluidized materials.
Experimental methods were developed to model gravimetric and energetic response of thermally decomposing materials. Gravimetric, heat flow, and specific heat data were obtained from a simultaneous thermogravimetric analyzer (DSC/TGA). A method was developed to combine data in an energy balance and determine an optimized heat of decomposition value. This method was effective for modeling simple reactions but not for complex decomposition.
Advanced method was developed to model mass loss using kinetic reactions. Kinetic models were expanded to multiple reactions, and an approach was developed to identify suitable multiple reaction mechanisms. A refinement method for improving the fit of kinetic parameters was developed. Multiple reactions were combined with the energy balance, and heats of decomposition determined for each reaction. From this research, this methodology can be extended to describe more complex thermal decomposition.
Effects of particle density and diameter on the minimum fluidization velocity were investigated, and results compared to empirical models. Effects of bed mass on pressure drop through fluidized beds were studied. A method was developed to predict hydrodynamic response of binary beds from the response of each particle type and mass. Resulting pressure drops of binary mixtures resembled behavior superposition for individual particles.Master of Science
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Jendoubi, Naoufel. "Mécanismes de transfert des inorganiques dans les procédés de pyrolyse rapide de la biomasse : Impacts de la variabilité des ressources lignocellulosiques sur la qualité des bio-huiles." Thesis, Vandoeuvre-les-Nancy, INPL, 2011. http://www.theses.fr/2011INPL062N/document.
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La pyrolyse rapide de biomasse est un procédé de conversion thermochimique qui permet de produire principalement des huiles de pyrolyse valorisables dans le domaine de l’énergie. Les espèces inorganiques initialement présentes dans la biomasse sont à l’origine de problèmes d’instabilité des huiles, de dépôts et d’encrassement. L’objectif de ce travail consiste à mieux comprendre les mécanismes de transfert des inorganiques depuis la biomasse vers les huiles dans les procédés de pyrolyse rapide.Une méthodologie est mise au point afin de quantifier la répartition des alcalins et alcalino-terreux (K, Ca, Mg et Na), identifiés comme les plus néfastes, dans les produits (charbons et huiles) issus de pyrolyse de bois et de paille de blé. Deux dispositifs complémentaires sont utilisés, pour lesquels les bilans de matière bouclent de façon très satisfaisante: un réacteur pilote de pyrolyse rapide en lit fluidisé et un réacteur laboratoire en four tubulaire. Dans tous les cas, le charbon séquestre 99% des éléments minéraux issus de la biomasse. En outre, grâce à un dispositif original de condensation fractionnée des huiles, on démontre que plus de 60% des inorganiques restants dans les huiles de pyrolyse proviennent des aérosols, ce résultat ouvrant une discussion quant à leur origine. Les teneurs en inorganiques des huiles sont par ailleurs fortement liées à la présence de fines particules de charbon mal séparées dans le procédé. Les possibilités de traitement amont ou aval sont discutées, afin de diminuer ces concentrations.Enfin, des expériences parallèles associées à un modèle permettent de décrire quantitativement les mécanismes de transfert entre les particules de charbon et une phase liquide lors du stockage d’huiles de pyrolyseBiomass fast pyrolysis is a promising process for the preparation of bio-oils dedicated to energy production. Inorganic species originally present in biomass are known to induce problems such as bio-oil instability, deposits and fouling. The purpose of the present work is to better understand the mechanisms of inorganic species transfer from biomass to bio-oils in fast pyrolysis processes. A methodology is developed for quantifying alkali and alkali-earth species (K, Ca, Mg, Na) distribution in the products (chars and bio-oils) issued from wheat straw and beech wood fast pyrolysis. Two complementary devices are used: a pilot plant fluidized bed reactor, and a horizontal tubular reactor. Mass balances closures are accurately achieved. 99 wt.% of the inorganic species originally contained in biomass are recovered in the chars. Thanks to an original bio-oils fractional condensation device, it is shown that more than 60 wt.% of the inorganic content of overall bio-oil is contained in the aerosols. Different assumptions of possible origins of the aerosols are discussed. Inorganic content of bio-oil is strongly connected to the presence of fine chars particles which are not efficiently separated by the cyclones, and, hence recovered in the bio-oils. The possibilities of upstream or downstream treatments are discussed in order to lower inorganic content of bio-oils. Finally, the mechanisms of inorganics transfers between char particles and a liquid phase, during bio-oil storage, are quantitatively described on the basis of side experiments associated to a model
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Mohamed, M. "Fluidised bed gasification and pyrolysis of woodchips." Thesis, University of Leeds, 1989. http://etheses.whiterose.ac.uk/21074/.
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The work presented in this thesis includes experimental investigation using a basic fluidised bed to gasify woodchips and cold modelling studies to improve the fluid bed reactor dynamics incorporating bed internals, such as draft tubes and jets. Low grade fuel gas was produced from woodchips as feedstock, in a 154 mm i/d fluidised bed as the main experimental part of the project using air as the gasifying medium. The influence of a number of process variables on the gasification process were studied including fuel feedrates, temperatures and bed heights, with respect to their effects on quality and quantity of the fuel gas produced. It was found that fuel gas of about 6 MJ/Nm3 can be obtained with temperatures in excess of 700 °c and with fuel feedrates in excess of 3.5 times stoichiometric. The process also benefitted from increasing the static bed heights of the fluidised bed, which was due to the better separation of the combustion and gasification zones. The cold modelling studies coducted using a 2-D glass model employing a draft tube a nd jet system, and using a novel photographic technique produced more realistic data. This showed that both the systems in question produced induced recirculation rates which can be controlled by the process variables such as bed height, bed and jet velocities. Further studies employing these systems for biomass conversion should prove that a better fuel gas quality and quantity can be achieved. In addition a variety of feedstocks can be utilised using the same reactor configuration.
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Kessas, Sid Ahmed. "Etude expérimentale de pyrolyse et de vapogazéification des boues de STEP en réacteurs à lit fluidisé entre 700 et 900°C : comparaison avec les déchets boisés." Thesis, Toulouse, INPT, 2019. http://www.theses.fr/2019INPT0113.
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La gazéification des biomasses lignocellulosiques apparaît actuellement comme une solution technologique prometteuse permettant la production d’un gaz à haute valeur ajoutée, utilisable dans de nombreuses applications. Cependant, les tensions qui commencent à apparaître sur le marché du bois incitent les acteurs du secteur à se tourner vers d’autres ressources lignocellulosiques telles que les résidus agricoles, les déchets verts municipaux et les boues de STEP. Suivant les cas, ces déchets sont vus comme des effluents à traiter dont le coût peut être parfois nul ou négatif. L’objectif de ces travaux est de mieux comprendre et modéliser les phénomènes qui se déroulent lors de la gazéification des déchets (boues de STEP et déchets verts municipaux) en lit fluidisé. Dans un premier temps, sont présentés successivement une étude de caractérisation physico chimique et texturale des intrants utilisés ainsi que des chars issus de leur pyrolyse rapide ainsi qu’une étude cinétique portant sur l’influence de la température de pyrolyse et de la nature de l’intrant sur la réactivité de char. Dans un second temps, sont exposés les résultats obtenus lors de la pyrolyse et de la vapogazéification des déchets dans un pilote de pyrogazéification en lit fluidisé entre 700 et 900 °C. Les études paramétriques ont permis de mettre en évidence l’effet des paramètre opératoires (température, rapport massique H2O/intrant, nature de l’intrant et du média fluidisé) sur les performances de la gazéification et d’identifier les paramètres clés permettant de contrôler la composition ainsi que le taux de production du gaz de synthèse. Par ailleurs, à partir des résultats obtenus sont proposés des schémas réactionnels pour la pyrolyse des déchets entre 700 et 900 °C. Enfin, les résultats d’une étude de modélisation du réacteur de gazéification des déchets en lit fluidisé intégrant les réactions de pyrolyse, de vapogazéification du char, de water-gas shift et de reformage des goudrons sont présentés et comparés avec les résultats expérimentaux afin de mieux comprendre l’effet des paramètres opératoires sur les taux d’avancement de différentes réactionsThe gasification of lignocellulosic biomass is viewed as a promising technological solution for theproduction of a high value-added gas that could be used in several applications. However,emerging tensions in the wood market are prompting industrial actors to turn to otherlignocellulosic resources, such as agricultural residues, municipal green waste and sewage sludge(SS). Depending on the case, these wastes are considered as effluents with a zero or negativecost. The objective of this work is to better understand and model the phenomena that occurduring the gasification of sewage sludge and green wastes in a fluidized bed. Firstly, aphysicochemical and textural characterization study of the selected fuels and their chars resultingfrom their rapid pyrolysis as well as a kinetic study on the influence of the pyrolysis temperatureand the nature of solid fuel on the reactivity of char were presented. Then, the results obtainedduring the pyrolysis and steam gasification of wastes, in a fluidized bed gasification pilot plant, arepresented for temperatures ranging between 700 and 900 °C. Parametric studies allows to betterunderstand the effect of operating parameters (temperature, H2O/fuel mass ratio, the nature of thefuel and the kind of the fluidized medium) on the gasification performance and to identify the keyparameters that control the composition, as well as the syngas production yield. Moreover,reaction schemes are proposed based on the experimental results, for the pyrolysis of wastesbetween 700 and 900 °C. Finally, the results of a modelling study of the gasifier, integrating thereactions of pyrolysis, char steam gasification, water-gas shift and tar reforming are presented andcompared to the experimental results in order to better understand the effect of the operatingparameters on the conversion rate of different reactions
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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.
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De, la Rey Jandri. "Energy efficiency in dual fluidised bed fast pyrolysis." Diss., University of Pretoria, 2015. http://hdl.handle.net/2263/57516.
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The Combustion Reduction Integrated Pyrolysis System (CRIPS) is a dual fluidised bed fast pyrolyser that was developed at the University of Pretoria for the conversion of biomass waste to biofuels. The dual fluidised bed design allows in situ catalytic upgrading of bio-oil, by providing the conditions required for the regeneration and decoking of catalysts. The first version of the CRIPS process (CRIPS 1) emphasised the need for an energy balance approach to model the pyrolysis process rather than a mass balance. CRIPS 1 experienced severe energy losses and as a result very poor performance was observed. The energy balance was set up in the enthalpy reference level since no shaft work was produced and the entire process was operated under constant atmospheric conditions. The enthalpy balance approach was set up to analyse the process performance and energy efficiencies of a CRIPS process and possibly the bio-oil energy content and yield that could be expected from such a process. The approach was used to derive the bio-oil properties and energy efficiencies for a number of scenarios based on the CRIPS process. The Higher Heating Value (HHV) of the bio-oil was derived using the total energy balance of the CRIPS process. The validity of the approach was confirmed by comparing the derived bio-oil HHV from CRIPS 1 of 14,2 MJ/kg with that of similar processes, in the range of 17-23 MJ/kg, as well as comparison to the operating data and process yields. The enthalpy balance approach was able to accurately model the operation of CRIPS 1 using energy and mass balances and therefore the approach was used in the design of CRIPS 2 to limit heat losses and improve the process efficiency by recovering heat from the exhaust of the combustor. The heat recovery resulted in significant improvements in the efficiency of CRIPS 2 (74%) compared to CRIPS 1 (33%). The final design of the CRIPS 2 process featured an annular design in which the combustion bed is located in a refractory cylinder, with the pyrolysis bed around the refractory. The design allowed for the addition of a heat exchanger inside the combustor which is responsible for the increase in efficiency.Dissertation (MEng)--University of Pretoria, 2015.
tm2016
Chemical Engineering
MEng
Unrestricted
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Bamido, Alaba O. "Design Of A Fluidized Bed Reactor For Biomass Pyrolysis." University of Cincinnati / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1535372231547049.
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Matta, Johnny. "Biomass Fast Pyrolysis Fluidized Bed Reactor: Modelling and Experimental Validation." Thesis, Université d'Ottawa / University of Ottawa, 2016. http://hdl.handle.net/10393/35516.
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Of the many thermochemical conversion pathways for utilizing biomass as a renewable energy source, fast pyrolysis is a promising method for converting and upgrading carbonaceous feedstocks into a range of liquid fuels for use in heat, electricity and transportation applications. Experimental trials have been carried out to assess the impact of operational parameters on process yields. However, dealing with larger-scale experimental systems comes at the expense of lengthy and resource-intensive experiments. Luckily, the advances in computing technology and numerical algorithm solvers have allowed reactor modelling to be an attractive opportunity for reactor design, optimization and experimental data interpretation in a cost-effective fashion. In this work, a fluidized bed reactor model for biomass fast pyrolysis was developed and applied to the Bell’s Corners Complex (BCC) fluidized bed fast pyrolysis unit located at NRCan CanmetENERGY (Ottawa, Canada) for testing and validation. The model was programmed using the Microsoft Visual Basic for Applications software with the motivation of facilitating use and accessibility as well as minimizing runtime and input requirements. The application of different biomass devolatilization schemes within the model was conducted, not only for biomass fast pyrolysis product quantity but also liquid product composition (quality), to examine the effect of variable reaction kinetic sub-models on product yields. The model predictions were in good agreement with the results generated from the experimental work and mechanism modifications were proposed which further increased the accuracy of model predictions. Successively, the formulation of the modelled fluid dynamic scheme was adapted to study the effect of variable hydrodynamic sub-models on product yields for which no significant effect was observed. The work also looked into effect of the dominant process variables such as feedstock composition, bed temperature, fluidizing velocity and feedstock size on measurable product outputs (bio-oil, gas and biochar) and compared the results to those generated from the experimental fast pyrolysis unit. The ideal parameters for maximizing bio-oil yield have been determined to be those which: minimize the content of lignin and inorganic minerals in the feedstock, maintain the dense-bed temperature in a temperature range of 450-520 ºC, maximize the fluidization velocity without leading to bed entrainment, and limit the feedstock particle size to a maximum of 2000 μm.
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Burton, Alan Hamilton. "Bed agglomeration during biomass fast pyrolysis in a fluidised bed reactor." Thesis, Curtin University, 2016. http://hdl.handle.net/20.500.11937/1885.
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This thesis explores the previously-unreported phenomenon of bed agglomeration during biomass fast pyrolysis in fluidised bed. Experimental work was carried out to characterise bed agglomerates formed. The differences in bed agglomeration behaviour were also identified among the fast pyrolysis of various mallee biomass components (wood, leaf and bark). A new parameter (sand loading) has also been developed for diagnosing bed agglomeration during biomass fast pyrolysis in fluidised bed under a wide range of conditions.
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Chern, Jyuung-Shiauu. "The pyrolysis and devolatilisation of coal in a fluidised bed." Thesis, University of Cambridge, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.627146.
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Boukis, Ioannis P. "Fast pyrolysis of biomass in a circulating fluidised bed reactor." Thesis, Aston University, 1997. http://publications.aston.ac.uk/9596/.
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The objective of this work was to design, construct, test and operate a novel circulating fluid bed fast pyrolysis reactor system for production of liquids from biomass. The novelty lies in incorporating an integral char combustor to provide autothermal operation. A reactor design methodology was devised which correlated input parameters to process variables, namely temperature, heat transfer and gas/vapour residence time, for both the char combustor and biomass pyrolyser. From this methodology a CFB reactor was designed with integral char combustion for 10 kg/h biomass throughput. A full-scale cold model of the CFB unit was constructed and tested to derive suitable hydrodynamic relationships and performance constraints. Early difficulties encountered with poor solids circulation and inefficient product recovery were overcome by a series of modifications. A total of 11 runs in a pyrolysis mode were carried out with a maximum total liquids yield of 61.50% wt on a maf biomass basis, obtained at 500°C and with 0.46 s gas/vapour residence time. This could be improved by improved vapour recovery by direct quenching up to an anticipated 75 % wt on a moisture-and-ash-free biomass basis. The reactor provides a very high specific throughput of 1.12 - 1.48 kg/hm2 and the lowest gas-to-feed ratio of 1.3 - 1.9 kg gas/kg feed compared to other fast pyrolysis processes based on pneumatic reactors and has a good scale-up potential. These features should provide significant capital cost reduction. Results to date suggest that the process is limited by the extent of char combustion. Future work will address resizing of the char combustor to increase overall system capacity, improvement in solid separation and substantially better liquid recovery. Extended testing will provide better evaluation of steady state operation and provide data for process simulation and reactor modeling.
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Mellin, Pelle. "Pyrolysis of biomass in fluidized-beds: in-situ formation of products and their applications for ironmaking." Doctoral thesis, KTH, Energi- och ugnsteknik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-172293.
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The iron and steel industry emitted 8 % of all CO2 emissions in Sweden, 2011. Investigating alternative energy carriers is the purpose of this thesis. By pyrolyzing biomass, an energetic solid, gaseous and liquid (bio oil) fraction is obtained. If pyrolyzing biomass in a fluidized-bed reactor, the highest value may be added to the combined products. Additional understanding of pyrolysis in fluidized beds is pursued, using Computational Fluid Dynamics (CFD) and comprehensive kinetic schemes. The obtained solid product is investigated as a bio-injectant in blast furnaces for ironmaking. A new approach of separately modeling, the primary and secondary pyrolysis, is developed in this thesis. A biomass particle devolatilizes during pyrolysis. Primary pyrolysis is the solid decomposition which results in the volatiles that can leave the particle. Secondary pyrolysis is the decompositions of these volatiles, primarily in the gas phase. The primary pyrolysis (35 species, 15 reactions) mainly occurs in the bed-zone and as such, the model needs to take into account the complex physical interaction of biomass-particles with the fluidizing media (sand) and the fluidizing agent (gas). This is accomplished by representing the components by Eulerian phases and implementing interaction terms, as well as using a Stiff Chemistry Solver for the implemented reactions. The secondary pyrolysis (not considering heterogeneous reactions), mainly occurs outside the bed zone in one phase. The fluid flow is simpler but the chemistry is more complex, with a larger variety of molecules emerging. Carrying out the simulations time-effectively, for the secondary pyrolysis (134 species, 4169 reactions) is accomplished by using Dimension Reduction, Chemistry Agglomeration and In-situ Tabulation (ISAT); in a Probability Density Functional (PDF) framework. An analysis of the numerical results suggest that they can be matched adequately with experimental measurements, considering pressure profiles, temperature profiles and the overall yield of gas, solid and liquid products. Also, with some exceptions, the yield of major and minor gaseous species can be matched to some extent. Hence, the complex physics and chemistry of the integrated process can be considered fairly well-considered but improvements are possible. A parametric study of reaction atmospheres (or fluidizing agents), is pursued as means of understanding the process better. The models revealed significant effects of the atmosphere, both physically (during the primary and secondary pyrolysis) and chemically (during secondary pyrolysis). During primary pyrolysis, the physical influence of reaction atmospheres (N2, H2O) is investigated. When comparing steam to nitrogen, heat flux to the biomass particles, using steam, is better distributed on a bed level and on a particle level. During secondary pyrolysis, results suggest that turbulence interaction plays an important role in accelerating unwanted decomposition of the liquid-forming volatiles. Steam, which is one of the investigated atmospheres (N2, H2O, H2, CO, CO2), resulted in a lower extent of unwanted secondary pyrolysis. Altough, steam neither resulted in the shortest vapor residence time, nor the lowest peak temperature, nor the lowest peak radical concentration; all factors known to disfavor secondary pyrolysis. A repeated case, using a high degree of turbulence at the inlet, resulted in extensive decompositions. The attractiveness of the approach is apparent but more testing and development is required; also with regards to the kinetic schemes, which have been called for by several other researchers. The solid fraction after pyrolysis is known as charcoal. Regarding its use in blast furnaces; modelling results indicate that full substitution of fossil coal is possible. Substantial reductions in CO2 emissions are hence possible. Energy savings are furthermore possible due to the higher oxygen content of charcoal (and bio-injectants in general), which leads to larger volumes of blast furnace gas containing more latent energy (and less non-recoverable sensible energy). Energy savings are possible, even considering additional electricity consumption for oxygen enrichment and a higher injection-rate on energy basis. A survey of biomass availability and existing technology suppliers in Sweden, suggest that all injection into Blast furnace M3 in Luleå, can be covered by biomass. Based on statistics from 2008, replacement of coal-by-charcoal from pyrolysis could reduce the on-site carbon dioxide emissions by 28.1 % (or 17.3 % of the emissions from the whole industry). For reference, torrefied material and raw biomass can reduce the on-site emissions by 6.4 % and 5.7 % respectively.Järn och stålindustrin stod för 8 % av alla koldioxidutsläpp i Sverige, 2011. Alternativa energibärare undersöks i denna avhandling. Genom pyrolys av biomassa, fås en energirik fast produkt, och samtidigt en gasformig och en vätskeformig produkt (bio-olja). Om en fluidbäddsreaktor används kan största möjliga mervärde tillföras de kombinerade produkterna. Djupare förståelse för pyrolys i fluidbäddar har eftersträvats med hjälp fluiddynamikberäkningar (CFD) och detaljerade kinetikscheman. Den fasta produkten har undersökts som bio-injektion i masugnar. En ny approach för modellering av primär och sekundär pyrolys separat, har utvecklats i denna avhandling. En biomassapartikel avflyktigas under pyrolys. Primär pyrolys är nedrytningen av den fasta biomassan till intermediärer (flyktiga ämnen) som kan lämna partikeln. Sekundärpyrolys är nedbrytning av dessa flyktiga ämnen, som primärt sker i gasfas. Primärpyrolysen (i detta arbete, 35 ämnen och 15 reaktioner) sker mestadels i bäddzonen och därmed behöver modellen ta hänsyn till den komplexa fysiska interaktionen av biomassapartiklarna med fluidbäddsmediet (sand) och fluidiseringsgasen. Detta åstadkoms med hjälp av Euleriska faser och interaktionstermer, samt en lösare för hantering av styva reaktionssystem. Sekundärpyrolysen sker huvudsakligen utanför bäddzonen. Fluiddynamiken är enklare men kemin är mer komplex, med fler ämnen närvarande. Att tidseffektivt köra beräkningarna, för sekundärpyrolysen (134 ämnen, 4169 reaktioner) åstadkoms med hjälp Dimensionsreducering, Kemiagglomerering och In-situtabulering (ISAT); som implementerats i en sannolikhetstäthetsfunktion (PDF). En analys av de numeriska beräkningarna antyder att de kan matchas med experimentella resultat, med avseende på tryckprofil, temperaturprofil, utbyte av gasformiga, fasta och vätskeformiga produkter. Dessutom, med några undantag, kan beräkningarna matchas ganska väl med de viktigaste gasformiga produkterna. Därmed kan de huvudsakliga fysiska och kemikaliska mekanismerna representeras av modellen men förbättringar är givetvis möjliga. En parameterstudie av reaktionsatmosfärer (dvs fluidiseringsgaser) genomfördes, för att förstå processen bättre. Modellen visade på betydande effekter av atmosfären, fysisk (både under primär och sekundärpyrolys), och kemiskt (under sekundärpyrolysen). Under primärpyrolysen undersöktes den fysiska inverkan av reaktionsatmosfärer (N2, H2O). När ånga jämfördes med kvävgas, visade det sig att värmeflödet sker mer homogent på både bäddnivå och på partikelnivå, med ångatmosfär. Under sekundärpyrolysen, så antyder resultaten på att turbulensinteraktion spelar en viktig roll för accelererad oönskad sekundärpyrolys av de vätskebildande ämnena. Ånga som är en av de undersökta atmosfärerna (N2, H2O, H2, CO, CO2), resulterade i den lägsta omfattningen av sekundärpyrolys. Dock så ledde en ångatmosfär varken till den lägsta residenstiden, den lägsta peaktemperaturen eller den lägsta radikalkoncentrationen; som alla normalt motverkar sekundärpyrolysen. Ett repeterat case, med hög turbulens i inloppet, gav betydande sekundärpyrolys av de vätskebildande ämnena. Attraktiviteten av approachen är given men mer testning och utveckling behövs, som också påkallats av andra forskare. Den fasta produkten efter pyrolys kallas träkol. Angående dess applicering i masugnar, så visar modelleringsresultaten att full substitution av fossilt kol går att göra. Betydande minskningar i koldioxidutsläpp är därmed möjliga. Energibesparingar är dessutom möjligt, tack vare det höga syreinnehållet i träkol (och biobränslen generellt), vilket ger större volymer av masugnsgas med högre värmevärde (och mindre sensibel värme som inte är utvinnbar). Energibesparingar är möjliga även om hänsyn tas till högre eleffekt för syrgasanrikning i blästerluften och en högre injektionsåtgång på energibasis. En översikt över biomassatillgången och existerande teknikleverantörer i Sverige, indikerar att all injektion i Masugn 3 (i Luleå) kan ersättas med biomassa. Baserat på statistik från 2008, så kan ersatt kol med träkol, minska de platsspecifika koldioxidutsläppen med 28.1 % (eller 17.3 % av alla utsläpp från stålindustrin). Som jämförelse kan torrifierad biomassa and obehandlad biomassa reducera utsläppen med 6.4 % respektive 5.7 %.
QC 20150827
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Agarwal, Gaurav. "Solid Fuel Blend Pyrolysis-Combustion Behavior and Fluidized Bed Hydrodynamics." Diss., Virginia Tech, 2013. http://hdl.handle.net/10919/51677.
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As a carbon neutral and renewable source of energy, biomass carries a high potential to help sustain the future energy demand. The co-firing of coal and biomass mixtures is an alternative fuel route for the existing coal based reactors. The main challenges associated with co-firing involves proper understanding of the co-firing behavior of blended coal-biomass fuels, and proper understanding of advanced gasification systems used for converting such blended fuels to energy.
The pyrolysis and combustion behavior of coal-biomass mixtures was quantified by devising laboratory experiments and mathematical models. The pyrolysis-combustion behavior of blended fuels was quantified on the basis of their physicochemical, kinetic, energetic and evolved gas behavior during pyrolysis/combustion. The energetic behavior of fuels was quantified by applying mathematical models onto the experimental data to obtain heat of pyrolysis and heat of combustion. Fuel performance models were developed to compare the pyrolysis and combustion performance of non-blended and blended fuels. The effect of blended fuel briquetting was also analyzed to find solutions related to coal and biomass co-firing by developing a bench scale fuel combustion setup. The collected data was analyzed to identify the effects of fuel blending and briquetting on fuel combustion performance, ignitability, flammability and evolved pollutant gases.
A further effort was made in this research to develop the understanding of fluidized bed hydrodynamics. A lab scale cold-flow fluidized bed setup was developed and novel non-intrusive techniques were applied to quantify the hydrodynamics behavior. Particle Image Velocimetry and Digital Image Analysis algorithms were used to investigate the evolution of multiple inlet gas jets located at its distributor base. Results were used to develop a comprehensive grid-zone phenomenological model and determine hydrodynamics parameters such as jet particle entrainment velocities and void fraction among others. The results were further used to study the effect of fluidization velocity, particle diameter, particle density, distributor orifice diameter and orifice pitch on the solid circulation in fluidized beds.Ph. D.
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Wiggers, Vinicyus Rodolfo. "Simulação, projeto e construção de uma unidade piloto multi-proposito para pirolise de residuos." [s.n.], 2003. http://repositorio.unicamp.br/jspui/handle/REPOSIP/267412.
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Orientadores: Maria Regina Wolf Maciel, Henry França Meier, Antonio Andre Chivanga BarrosDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica
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Resumo: A pirólise, uma das muitas alternativas de processos de conversão química de resíduos sólidos, tem recebido uma atenção especial de ambientalistas, engenheiros e da comunidade científica. Este processo tem sido testado em um número incontável de plantas piloto, e muitos sistemas em escala industrial já são operados com sucesso. Sofrendo aquecimento em uma atmosfera livre de oxigênio, muitas substâncias orgânicas de cadeia longa, podem ser fracionadas via craqueamento térmico e reações de condensação, em frações gasosas, líquidas e sólidas de menor peso molecular com maior valor econômico. Ao contrário da incineração que é altamente exotérmica, a pirólise é endotérmica, ocorre numa faixa de temperatura da ordem de 300 a 600°C e apresenta vantagens como a menor formação de dioxinas e a possibilidade de processo autotérmico. Este trabalho tem o propósito de simular, projetar e construir uma planta piloto de pirólise em reator de leito móvel através de solução de modelos matemáticos e métodos numéricos. Além disso, pretende-se desenvolver uma estratégia do tipo problema inverso para ajuste numérico de parâmetros térmicos e cinéticos do processo. Para tanto, projetou-se e montou-se um aparato experimental em escala piloto, com finalidade multi-propósito, para aquisição de dados do processo com e sem reação, mediante o desenvolvimento e uso do modelo microscópico unidimensional e permanente de conservação da massa e da energia
Abstract: Pyrolysis, one of many solid waste chemical conversion processes, has been receiving a special atenttion from engineers, researches and environment specialists. The pyrolysis has been tested in many pilot plants, and some industrial plants are operated with success. Heating in a controled atmosphere absenced of oxygen, an organic portion of waste materials can be converted into mixture gases, oils with lower molecular weight and others products with higher economic value. This trasnformation occurs through thermal cracking and condensation reaction. Whereas incineration is exothermic, pyrolysis is endothermic and runs in range temperatures from 300 to 600°C. This process still presents some advantages like smaller dioxines formation than the incineration and also the possibility of autothermal operation of the process This work has the propose to simulate, project and build a pilot plant of pyrolysis with a fluidised bed reactor, by using mathematical modelling and numerical methods for simulation of the process It also intends to develop strategies to solve an inverse problem to predict thermal and kinetics parameters of the model from experimental data obtaneid in a pilot plant and a metodology to determine a thermic and kinetic parameters of solid waste. To get this objective, a microscopic model l-D and steady state, of mass and energy conservation was developed, the simulation for design and the construction of an experimental aparatus in a pilot plant scale was realized, to get a process data with and without reaction, to intend a scale-up from process
Mestrado
Desenvolvimento de Processos Químicos
Mestre em Engenharia Química
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Christodoulou, Mélina. "Pyrolyse de bois dans les conditions d'un lit fluidisé : étude expérimentale et modélisation." Thesis, Université de Lorraine, 2013. http://www.theses.fr/2013LORR0200/document.
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Ce travail s'inscrit dans le projet français de gazéification de la biomasse : le projet Gaya. C'est un vaste programme R&D partenarial coordonné par GDF SUEZ et soutenu par l'ADEME. L'objectif du projet Gaya est de développer une filière décentralisée de production de bio-méthane à partir de la gazéification de la biomasse selon un procédé thermochimique de deuxième génération. L'objectif de cette thèse est de réaliser un modèle de pyrolyse de biomasse représentatif des conditions du lit fluidisé de gazéification développé dans ce projet. Un pilote expérimental, le four à image, a été développé pour reproduire au mieux les conditions de chauffage d'un lit fluidisé à 850°C. Ce pilote permet de récupérer l'ensemble des produits de pyrolyse pour une analyse ultérieure. De là, les cinétiques des réactions de pyrolyse sont déterminées par modélisation des processus physico-chimiques et optimisation à partir des résultats expérimentaux. Le craquage des vapeurs primaires de pyrolyse éjectées de la particule de biomasse est étudié durant 300 millisecondes après leur éjection de la particule de biomasse. Ces expériences de craquage sont menées sur le montage expérimental combinant un réacteur tubulaire de pyrolyse et un réacteur parfaitement auto-agité de craquage. Le modèle développé permet de représenter la pyrolyse de la biomasse introduite dans le réacteur de gazéificationThis study contributes to the French biomass gasification project: Gaya project. It is a large R&D project financed by ADEME and coordinated by GDF SUEZ. The project GAYA will develop a demonstration platform for a new biomass gasification and methanation process. In this context, our objective is to build a biomass pyrolysis model, representative of the conditions encountered in the fluidized bed gasifier developed in this project. An experimental machine, the vertical image furnace, has been developed to reproduce the heat conditions of the fluidized bed gasifier at 850°C. This experimental model permits to collect all the pyrolysis products for a later analysis. Then, kinetics parameters are determined from both the physico-chemical process and the optimization of experimental results. The thermal cracking of condensable vapours, is studied during the first 300th milliseconds after their ejection from the biomass particle. For this purpose, cracking experiments are led on the experimental machine which combines a tubular pyrolysis reactor and a continuous self-stirred tank cracking reactor. The model developed allows us to represent the biomass pyrolysis introduced in the gasification reactor
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Wildegger-Gaissmaier, Anna Elisabeth. "Fluidized bed utilization of South Australian coals." Title page, contents and abstract only, 1988. http://web4.library.adelaide.edu.au/theses/09PH/09phw672.pdf.
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Authier, Olivier. "Etude découplée des phénomènes physicochimiques impliqués dans les réacteurs de gazéification de la biomasse. Application au cas d'un lit fluidisé double." Thesis, Vandoeuvre-les-Nancy, INPL, 2010. http://www.theses.fr/2010INPL015N/document.
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Parmi les technologies de gazéification de la biomasse, le gazéifieur à lit fluidisé double permet la production d’un gaz de synthèse contenant du méthane. L’étude des processus physicochimiques impliqués dans le gazéifieur est rendue difficile par le fait qu’ils se produisent simultanément. Dans cette thèse, les principales réactions chimiques sont étudiées de manière découplée, indépendamment les unes des autres à l’aide de dispositifs de laboratoire originaux et dans des conditions thermiques semblables à celles du gazéifieur. Les processus intraparticulaires contrôlant la pyrolyse de la biomasse ainsi que les réactions gaz/solide (vapogazéification du charbon et craquage thermique et catalytique des vapeurs sur olivine) sont étudiées au moyen d’un four à image. Les expériences de craquage thermique homogène des vapeurs sont réalisées dans un réacteur parfaitement auto-agité par jets gazeux. Tous les produits formés par les réactions sont recueillis et analysés. Les bilans de matière bouclent de façon très satisfaisante. Le régime de chaque réaction est discuté sur la base d’une analyse de temps caractéristiques. Les paramètres cinétiques des réactions sont déterminés par modélisation des processus et optimisation à partir des résultats expérimentaux. Les mécanismes possibles de formation et de consommation du méthane sont identifiés et discutés. Le gazéifieur est modélisé sur la base d’un modèle de grains (réactions primaires de pyrolyse), des réactions secondaires, de l’hydrodynamique des phases solides et gazeuse et des transferts. La méthodologie de découplage est enfin validée par comparaison des résultats du modèle avec des mesures réalisées sur le gazéifieur de 8 MW de Güssing (Autriche)Among the biomass gasification technologies, the dual fluidized bed gasifier may be used to produce a methane-rich syngas. Analysis of all the physicochemical phenomena involved inside the gasifier is difficult because they all occur simultaneously. In this thesis, the main chemical reactions are decoupled and studied independently one of each other at the scale of original laboratory facilities in thermal conditions close to those encountered in the gasifier. Intraparticular reactions of biomass pyrolysis and gas/solid reactions (char-steam gasification and catalytic thermal cracking of vapors on olivine) are carried out with an image furnace. Experiments related to gas-phase vapors thermal cracking are performed inside a continuous self stirred tank reactor. All the products formed by the reactions are recovered and analyzed. Mass balance closures are achieved accurately. Controlling steps of each reaction are discussed on the basis of a characteristic times analysis. Kinetic parameters are determined according to both processes modelings and optimizations from the experimental results. Different ways of possible methane formation and consumption mechanisms are identified and discussed. The gasifier is modelled by considering a single-particle model (primary pyrolysis reactions), secondary reactions, solids and gas-phase hydrodynamics and transfers. Finally, the decoupling methodology is validated from the comparison of model results with measurements performed at the 8 MW Güssing gasifier (Austria)
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Antreou, Evangelia. "Improved microwave-assisted pyrolysis of HDPE using catalysts and a fluidised-bed reactor." Thesis, University of Cambridge, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.648805.
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Papakidis, Konstantinos. "Computational modelling of the fast pyrolysis of biomass in bubbling fluidised bed reactors." Thesis, Aston University, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.497372.
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The aim of the current thesis is to model the various fluid-particle interactions in an 150g/h bubbling fluidised bed reactor. Mass, momentum and heat transfer from the bubbling bed of the reactor to the discrete biomass particles are modelled and analysed. The Eulerian-Eulerian approach is used to model the bubbling behaviour of the sand, which is treated as a continuum. The biomass particle motion inside the reactor is computed by integrating the equations of motion using drag laws, dependent on the local volume fraction of each phase. Reaction kinetics are also incorporated in the computational code according to the literature, using a two stage global model which takes into account the intra-particle secondary reactions due to the catalytic effect of char, resulting on secondary vapour cracking.
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Gerhauser, Heiko. "CFD applied to the fast pyrolysis of biomass in fluidised beds." Thesis, Aston University, 2003. http://publications.aston.ac.uk/9645/.
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Wang, Xiaoquan. "Biomass fast pyrolysis in fluidized bed product cleaning by in-situ filtration /." Enschede : University of Twente [Host], 2006. http://doc.utwente.nl/51114.
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Middleton, Stephen Philip. "Partitioning of sulphur and nitrogen in pyrolysis and gasification of coal in a fluidised bed." Thesis, Loughborough University, 1997. https://dspace.lboro.ac.uk/2134/27972.
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The aim of this study was to gain a better understanding of the processes governing the distribution of the heteroatoms, sulphur and nitrogen, between the various products formed during fluidised bed pyrolysis/gasification under conditions particularly relevant to industrial hybrid combined cycle power generation.
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Hung, Jessica Joy. "The Production of Activated Carbon from Coconut Shells Using Pyrolysis and Fluidized Bed Reactors." Thesis, The University of Arizona, 2012. http://hdl.handle.net/10150/243968.
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A production plant was designed to produce 14.5 metric tons of activated carbon per day from coconut shells, in order to capture 2% of the projected market for activated carbon in air purification applications by 2014. The production process consists of a pyrolysis stage and an activation stage. A downdraft gasifier was utilized as the pyrolysis reactor in order to maximize the energy efficiency of the process, and a separate cyclone and condenser were added to capture and purify the valuable byproducts of the pyrolysis reaction. A fluidized bed reactor was utilized as the activation reactor, due to its superior heat and mass transfer properties over conventional reactors currently used in industry. An extensive heat exchanger network was implemented to capture and recycle the heat and water produced by the activation reaction, in order to minimize the plant’s thermal and water footprint. With an interest rate of 20%, the plant is expected to have a net present value of $43.8 million at the end of its ten-year lifetime. Due to the expected high product demand and anticipated profits, construction of the plant is strongly recommended.
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Cooke, Louise A. "The effect of a ZSM-5 containing catalyst on the fluidised bed fast pyrolysis of pine wood." Thesis, Aston University, 1999. http://publications.aston.ac.uk/9626/.
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Silva, Fabio Nascimento da. "Estudo da pirolise de poliamida-12 em leito fluidizado borbulhante." [s.n.], 2009. http://repositorio.unicamp.br/jspui/handle/REPOSIP/264085.
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Orientador: Caio Glauco SanchezDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica
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Resumo: O objetivo do presente trabalho consiste em avaliar a degradação térmica de poliamida-12 obtida como resíduo de processos de prototipagem rápida por via pirolítica para obtenção de produtos líquidos e gasosos que possam ser usados como insumos e para a geração de energia em indústrias. Foram utilizadas diferentes configurações no leito fluidizado, alterando parâmetros de temperatura, velocidade de fluidização e altura do leito de inerte. A poliamida-12 é utilizada em máquinas de prototipagem rápida para confecção de moldes e peças. Após cerca de 250 horas de utilização, o material perde suas características originais sendo, então, descartado. O descarte da poliamida é feito armazenando o material em tambores até que seja elaborada uma solução alternativa. O estudo da pirólise de poliamida-12 apontou que o material é convertido em gás e produto líquido, não sendo gerado resíduo sólido após o processo. O gás gerado possui concentrações consideráveis de H2 e N2. Foi demonstrado que baixas velocidades de fluidização e elevadas temperaturas favorecem a formação de gás, contudo, a altura do leito fixo não influenciou de maneira significativa os resultados. O estudo comprova a aplicabilidade da reciclagem de PA-12 por processos de pirólise, gerando basicamente gás de síntese. Palavras Chave: Poliamida-12, pirólise, reciclagem, pirólise de polímeros
Abstract: The aim of this work is to evaluate the thermal degradation by pyrolysis of polyamide-12 obtained as residue from rapid prototyping processes for generation of liquids and gaseous products that should be used as supplies and to energy generation on industries. Were utilized different bed's configurations, changing parameters as temperature, fluidization air speed and inert bed's height. The polyamide-12 is utilized in rapid prototyping machines for the confection of moulds and pieces. After about 250 hours of utilization, the material loses it original characteristics and it is discarded. The discard of used polyamide has been done by saving the material in gallons until another way be elaborated. The study of pyrolysis of polyamide-12 shown the material conversion into gas and liquid product, without production of solid waste after the process. The gas has considerable concentrations of H2 and N2. It was demonstrated that low fluidized gas speed and high temperatures increases the gas formation, however, the fixed bed height did not have several influence in the results. This study confirms the applicability of PA-12 recycling by pyrolysis processes, generating synthesis gas. Key Words: Polyamide-12, pyrolysis, recycling, polymers pyrolysis
Mestrado
Termica e Fluidos
Mestre em Engenharia Mecânica
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Gulshan, Samina. "Fast Pyrolysis of Biomass in a Fluidized Bed for Production of Bio-oil and Upgradation by Ex-situ Catalytic Bed." Thesis, KTH, Skolan för industriell teknik och management (ITM), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-254895.
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Production of bio-oil from biomass is now becoming best substitute of fossil fuels in the transportation sector. Pyrolysis is one of the most promising route to produce bio-oil from biomass. However, bio-oil needs to be upgraded due to presence of high percentage of oxygenated compounds. Catalytic fast pyrolysis is a very efficient way to produce and upgrade the bio-oil either it is in-situ or Ex-situ arrangement. This study presents the experimental investigation of fast pyrolysis of lignocellulosic biomass by ex-situ catalytic upgradation. The whole process consists of four parts: biomass grinding and sieving, pyrolysis, ex-situ fixed bed and vapours quenching. The pyrolysis experiment has been performed with nitrogen with or without catalyst to investigate the yield of different products. The analysis of results shows that higher yield of gas is obtained from catalytic upgradation together with the low yield of oil. The more oxygen was removed into CO and CO2 from vapours due to more cracking reactions occurred on catalytic bed. The yield of oil was decreased in catalytic experiments, but it has relatively good energy content due to no water in viscous phase and low acid number. The char yield was same for non-catalytic and catalytic experiments.Framställning av bioolja från biomassa är ett av de bästa alternativen som kan ersätta fossilabränslen i transportsektorn. Pyrolys är en av de mest lovande teknologierna för att framställabioolja från biomassa. Bioolja behöver dock uppgraderas på grund av en hög andeloxygenerade föreningar. Katalytisk snabbpyrolys är en effektiv metod för att producera ochuppgradera sådan bioolja, antingen genom in-situ eller ex-situ processuppställning. Denna studie presenterar en experimentell undersökning av snabbpyrolys av lignocellulosiskbiomassa kombinerat med ex-situ katalytisk uppgradering. Processen består av fyra delar:förbereda lämplig partikelstorlek av biomassa, pyrolys, ex-situ fastbädd och kondensering avångor. Pyrolysexperiment har genomförts med vätgas med och utan katalysator för attundersöka utbytet av olika pyrolysprodukter. Resultaten visar att en katalytisk uppgraderingger en ökad andel gasprodukt samt ett lågt utbyte av olja. Stor andel syre avlägsnades från oljansom CO och CO2 genom krackningsreaktioner i den katalytiska bädden. Oljeutbytet var lägrevid katalytiska experiment, men visade ett lovande energivärde pga en minskad andel vattensamt ett lägre syratal. Utbytet av kol var detsamma för katalytiska och icke-katalytiskaexperiment.
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Myo, Min Win. "Thermochemical conversion characteristics of gas and tar generation from waste biomass and plastics." Kyoto University, 2020. http://hdl.handle.net/2433/253264.
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Cadile, Claudia. "Modélisation DEM et approche expérimentale de la dynamique d'un système réactif en lit fluidisé dense : application à la gazéification de la biomasse." Thesis, Aix-Marseille, 2014. http://www.theses.fr/2014AIXM4769/document.
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Le travail réalisé en collaboration entre l’entreprise CNIM et le laboratoire IUSTI a permis la miseen place d’un outil de simulation numérique afin d’étudier à l’échelle locale différents phénomènescouplés qui se produisent dans un réacteur de gazéification en lit fluidisé dense. L’approche choisie,DEM (Discrete Element Method), est basée sur le suivi de paquets de particules. Les résultats desimulation ont été comparés à des mesures expérimentales réalisées dans les laboratoires IUSTIet LERMAB : mesure de pression dans un lit fluidisé peu profond et caractérisation de la réactionde pyrolyse par suivis temporels de la masse volumique par une méthode innovante et de latempérature de la particule de biomasse ainsi que la composition des gaz produits. À plus grandeéchelle, les prédictions numériques du code ont été comparées à des mesures expérimentales deprofil de vitesse des particules et de mélange et ségrégation issues de la littérature. Les résultatsnumériques du lit fluidisé bisolide sans et avec réactions chimiques, obtenus sont en bon accordavec les mesures expérimentales. Ils ont permis de mettre en évidence le fort couplage entre lesphénomènes hydrodynamiques et thermochimiques.Ces travaux ouvrent de nouvelles perspectives tant sur le plan de l’expérimentation que de la simulation numérique où l’approche DEM retenue a montré un fort potentiel. L’extrapolation dumodèle DEM pour la simulation de la gazéification à des réacteurs industriels reste encore un défiau regard des ressources informatiquesEnergy production from green and renewable resources, such as biomass, are currently experiencinga significant growth. Thermochemical conversion of this biomass by gasification is a process usedfor over a century but still requires significant developments in terms of rentability optimizationand quality improvement of products gases.The work carried out in collaboration between the CNIM company and the IUSTI laboratoryallowed the establishment of a numerical simulation tool to study locally different coupled phenomenaoccurring in a dense fluidized bed gasification reactor. The chosen approach, DEM (DiscreteElement Method), is based on the monitoring of particle packets. The simulation results werecompared to experimental measurements realised in IUSTI and LERMAB laboratories : measuringpressure in a shallow fluidized bed and characterization of pyrolysis reaction with the timetracking of particle density by an innovative method, temperature and the composition of theproducts gases. On a larger scale, the numerical code predictions were compared with velocity,particles mixing and segregation profiles from experimental measurements of the literature. Theobtained numerical results of bi-solid fluidized bed with and without chemical reactions are ingood agreement with the experimental measurements. It helped to highlight the strong couplingbetween hydrodynamic and thermochemical phenomena.This work opens up new perspectives on the experimental plan and numerical simulation whichDEM approach has shown great potential. The extrapolation of the DEM model for the simulationof gasification industrial reactors remains a challenge in terms of computer resources
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Arnould, Philippe. "Mise en oeuvre de lits fluidises sous plasma : application a la decomposition de la calcite et modelisation." Paris 6, 1986. http://www.theses.fr/1986PA066009.
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Conception de nouveaux reacteurs pouvant fonctionner a haute temperature. Mise en oeuvre de differents types de reacteurs (reacteur agite, reacteur a lit horizontal). Dans ces deux cas, on etudie la cinetique du transfert de chaleur et de matiere. Presentation d'un modele cinetique tenant compte du transfert de chaleur pour la decomposition de la calcite
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Le, Dirach Jocelyn. "Contribution à l'industrialisation d'un procédé de gazéification." Thesis, Vandoeuvre-les-Nancy, INPL, 2008. http://www.theses.fr/2008INPL024N.
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La diversification des sources d’énergies s’appuyant sur les énergies renouvelables doit contribuer à réduire la part des énergies fossiles dans la production d’électricité, en accord avec les directives européennes qui prévoient, pour la France de produire 21% de notre énergie à partir d’EnR en 2010.Les travaux rapportés dans ce mémoire s’attachent à l’industrialisation d’un procédé de gazéification de bois en vue de la production de chaleur et d’électricité. Des expériences de pyrolyse rapide de bois ont été menées sous diverses conditions expérimentales (densité de flux entre 0.9 et 6.3 MW/m², humidité entre 0 et 60%) pour comprendre et analyser les phénomènes fondamentaux impliqués lors de la gazéification du bois. Les divers produits (char, vapeurs et gaz) sont récupérés et analysés. Les résultats permettent de déterminer les rendements en chacun des produits pour différentes conditions expérimentales.La modélisation numérique du phénomène de pyrolyse du bois a ainsi été réalisée en se basant sur les données cinétiques fournies par la littérature puis comparée aux résultats expérimentaux. Même s’il n’y a pas concordance parfaite, les ordres de grandeur sont respectés. Ces modèles servent de base à la modélisation d’un réacteur de gazéification basé sur le réacteur DFB de Güssing incorporant la description hydrodynamique, la pyrolyse du bois, la gazéification du char et les réactions des vapeurs et des gaz. Ce modèle permet ainsi de déterminer l’efficacité du réacteur et ses différents paramètres opératoires.Mots clés : bois, pyrolyse, gazéification, processus élémentaires, modélisation, Güssing, énergies renouvelables, lit fluidisé circulant, génie des procédésDiversification of energy sources based on renewable energies must contribute to reduce the share of fossil fuels in power generation, in agreement with the European directives which impose to France to generate 21% of its energy from renewable energies before 2010.The present work reported in this manuscript focus on the industrialization of a wood gasification process for the production of heat and electricity. Experiments of wood fast pyrolysis were performed under various experimental conditions (flux density between 0.9 and 6.3 MW/m2, moisture between 0 and 60%) for understanding and analysis of fundamental phenomena related to the gasification of wood. The various products (char, condensible vapours and gases) are recovered and analyzed. The results help to determine the yields of each of the products for various experimental conditions.The numerical modeling of wood pyrolysis phenomena has been achieved on the basis of kinetic data found through literature review and then compared to the experimental results. Even if there is no perfect agreement, orders of magnitude are respected. These models are used as a basis to develop a gasification reactor model for Güssing DFB reactor, including the hydrodynamics description, wood pyrolysis, char gasification, vapours and gases reactions. This model is used to determine the efficiency of the reactor and its various operating parameters
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Mesa, Perez Juan Miguel. "Testes em uma planta de pirolise rapida de biomassa em leito fluidizado : criterios para sua otimização." [s.n.], 2004. http://repositorio.unicamp.br/jspui/handle/REPOSIP/257207.
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Orientador: Luis Augusto Barbosa CortezTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agricola
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Resumo: Neste trabalho são apresentados e discutidos testes experimentais conduzidos na planta de pirólise rápida de biomassa da Unicamp visando à operação estável do reator de leito fluidizado em regime borbulhante. Esses resultados permitiram identificar os principais problemas relativos à operação do reator, assim como analisar as possíveis causas e as soluções postas em prática. O problema de maior influência sobre o trabalho estável do reator foi o vazamento de gases da pirólise pelo sistema de alimentação, mostrando-se como solução mais eficaz, o aumento da porcentagem de preenchimento da rosca alimentadora com biomassa. Após a estabilização da operação do reator, estudou-se a influência da porcentagem de ar em relação ao estequiométrico e da altura do leito fixo de inerte sobre as características de qualidade e rendimento dos finos de carvão. O estudo permitiu concluir que, para 8% de ar em relação ao estequiométrico e 207 mm de altura do leito fixo de areia, a pirólise acontece de forma mais intensa. Essa análise parte do princípio de que a pirólise é um processo de concentração de carbono nos finos de carvão e liberação de oxigênio da biomassa. Tomando-se como base os resultados anteriores, foram conduzidos novos testes visando à coleta e caracterização de amostras de bio-óleo. Os resultados mostraram que tanto a viscosidade quanto o teor de insolúveis das amostras de bio-óleo apresentaram altos valores, quando comparados com dados da literatura. Com base na experiência acumulada dos estudos anteriores é proposta e parcialmente avaliada uma estratégia para a otimização e a mudança de escala do processo de pirólise em leito fluidizado. A estratégia objetiva o uso das informações obtidas a partir dos modelos matemáticos ajustados no reator modelo para o projeto de reatores comerciais. O procedimento anterior mostra-se eficiente quando os fatores independentes e seus níveis durante a otimização do processo no reator modelo são criteriosamente selecionados. Finalmente, são mostradas, por meio de um exemplo, as dificuldades durante a mudança de escala quando os experimentos realizados no reator modelo não são planejados com o objetivo de reduzir as distorções na escalada
Abstract: This research discusses a strategy to optimize and scale up the pyrolysis process in fluidized bed. The strategy uses adjusted mathematical models applied to the model reactor to the project commercial reactors. Several steps of that procedure were appraised based on the adjusted model for the percentage of elutriated fine charcoal in the model reactor. It was verified that, during the scale-up, the mathematical model was not effective; however it predicts problems associated to the change of scale. Exploratory tests were carried out to guarantee the stable operation of the reactor, which made possible the identification of the main problems related to the procedure during the fast pyrolysis in fluidized bed with atmospheric air. The possible causes of the problems, as well their solutions, are also analyzed. The greater difficulty in the operation was the leak of pyrolitic gases through the feeding system. The increase of the percentage of biomass stuffing of the feeding thread was the most effective solution to avoid gas leaking. When the reactor operation was stabilized, the influence of the percentage of air in relation to the stoichiometric and the height of the inert fixed bed on the quality characteristics and yield of the fine charcoal. That study allowed conclude that, for 8% of air in relation to the stoichiometric and 207 mm of the fixed sand bed height, the pyrolysis happens in a more intense way. The analysis was based on the principle that the pyrolysis process is a process to concentrate carbon in charcoal and release oxygen from the biomass. Finally, bio-oil samples were collected using a centrifugal separator and characterized. The viscosity and the insoluble content presented high values, when compared with the literature data. Based on those results, a system to bio-oil recovery was projected and built. It combines the direct contact followed by centrifugal separation
Doutorado
Construções Rurais e Ambiencia
Doutor em Engenharia Agrícola
32
Camargo, Fernando de Lima. "Estudo da pirolise rapida de bagaço de cana em reator de leito fluidizado borbulhante." [s.n.], 2006. http://repositorio.unicamp.br/jspui/handle/REPOSIP/264132.
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Orientador: Caio Glauco SanchezTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica
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Resumo: O conteúdo de energia da biomassa pode ser explorado por combustão direta ou outros processos de conversão: físicos, biológicos e termoquímicos. Entre os processos termoquímicos há a pirólise que é atrativa devido à conversão de biomassa sólida para produtos líquidos apresentando algumas vantagens tais como no transporte, no armazenamento, na manufatura, reprocessamento e flexibilidade na produção. O objetivo deste trabalho foi construir e operar um reator de leito fluidizado em escala de bancada com alimentação contínua de biomassa para converter o bagaço de cana de açúcar em líquidos via pirólise rápida. O reator construído tem 0,095 m de diâmetro interno e foi utilizado areia fina como material inerte. Foi desenvolvido um novo alimentador para controlar a alimentação contínua de biomassa no leito e um sistema isocinético de amostragem com o objetivo de quantificar os produtos gerados no processo. Uma metodologia experimental foi escrita para a realização de testes de pirólise rápida de biomassa. Experimentos foram realizados usando catalisadores de craqueamento de petróleo (FCC) e injeção de água no fluxo para avaliar a influência destes fatores no processo. Temperatura e altura estática do leito também foram consideradas neste estudo. A altura estática do leito e a temperatura foram as variáveis mais relevantes na maioria dos testes realizados e necessitam de atenção especial na conversão para produtos líquidos
Abstract: The energy content of biomass can be exploited by direct combustion or after conversion by physical, biological and thermochemical processes. Among the thermochemical processes there is the pyrolysis that is an attractive process because it provokes the conversion of solid biomass into liquids products. Such conversion presents many advantages in transport, storage, handling, retrofitting, combustion and flexibility in production and marketing. The goal of this work was to build and operate a bench scale fluidized bed reactor to convert sugarcane bagasse into liquid products by fast pyrolysis. The reactor design presents 0,095 m internal diameter and fine sand was used as inert material for the fluidized bed. A new hopper to control the continuous feed of biomass in the reactor and an isokinetic sampling device to quantify the products obtained in the process. An experimental methodology was written for tests with biomass. Experimental essays carried out with fluid catalytic cracking and water injection in the stream in order to verify these effects in the process. Temperature and static height of the bed was also considered in this study. The static height of the bed and the temperature were the variables more important, requiring special attention in the conversion process
Doutorado
Termica e Fluidos
Doutor em Engenharia Mecânica
33
Borges, Fernanda Cabral. "Estudo do processamento termoquímico de biomassas com micro-ondas : pirólise rápida de biomassas residuais e microalgas." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2014. http://hdl.handle.net/10183/100151.
Full textAbstract:
Alguns conceitos de biorrefinarias estão baseados em processos termoquímicos, sendo a pirólise rápida um dos mais promissores desses processos. Os produtos da pirólise rápida são: o bio-óleo, gases combustíveis e carvão, sendo a distribuição típica de 50:30:20 em base mássica. O bio-óleo é o principal produto, e pode ser diretamente usado como combustível, ou pós-processados para a obtenção de químicos de maior valor agregado. O aquecimento com micro-ondas, amplamente empregado na química verde, começa a ser estudado como uma alternativa de aquecimento. Entretanto os rendimentos alcançados em bio-óleo são inferiores aos obtidos pela pirólise rápida convencional, devido essencialmente às suas baixas taxas de aquecimento. Para resolver esse problema esta tese está propondo a utilização de absorvedores de micro-ondas para auxiliar no processo de aquecimento, e também permitir a alimentação semi-contínua e contínua de biomassa ao processo. O uso de leito fluidizado e catalisadores pode ser integrado a esse conceito. As condições de pirólise-rápida são alcançadas devido ao aumento da taxa de aquecimento da biomassa, que passa a ser aquecida de forma híbrida pelo mecanismo de condução de calor através das partículas de absorvedores de micro-ondas aquecidos, e diretamente através do aquecimento dielétrico por micro-ondas. O aumento das taxas de aquecimento resulta em maiores velocidades de reação, possibilitando um aumento de rendimento em bio-óleo. Esse conceito foi testado experimentalmente em uma unidade em escala de bancada para o processamento de biomassas residuais e microalgas, usando carbeto de silício (SiC) como absorvedor de micro-ondas. Foram verificadas elevadas taxas de aquecimento, sendo a biomassa aquecida e os voláteis removidos do reator quase instantaneamente. Foram obtidos 65% e 64% em rendimentos de bio-óleo para a serragem de madeira e farelo de sabugo de milho, respectivamente. O mesmo sistema foi utilizado para testar a pirólise rápida catalítica. Microalgas foram processadas com e sem a presença de HZSM-5. Rendimentos de 57% e 59% em bio-óleo foram alcançados para Chlorella sp. e Nannochloropsis, respectivamente. Verificaram-se maiores rendimentos comparados com a literatura. Esses resultados indicam que o conceito de pirólise rápida com aquecimento por micro-ondas é tecnicamente viável, necessitando de estudos complementares para evidenciar a sua viabilidade econômica.Some concepts of biorefineries are based on thermochemical processes and fast pyrolysis is one of the most promising of these processes. The fast pyrolysis products are biooil, fuel gas and char, with typical distribution of 50:30:20 in weight basis. The bio-oil is the main product, and it can be directly used as fuel, or post-processed in order to obtain higher value added chemicals. The microwave heating, widely used in green chemistry, begins to be studied as an alternative heating. However the yields achieved in bio-oil are lower than those obtained by the conventional fast pyrolysis, mainly due to its low heating rates. To solve this problem this thesis is proposing the use of microwave absorbers to improve the heating process, and that also allow semi-continuous and continuous feeding of biomass to the process. The use of fluidized bed and catalysts can be integrated into this concept. The fast pyrolysis conditions are achieved due to increased heating rate of biomass, which becomes heated in a hybrid way by heat conduction mechanism from heated microwave absorbers, and directly through the dielectric heating from microwaves. The increase in heating rates results in higher reaction rates, allowing higher yields of bio-oil. This concept has been experimentally tested in a bench scale unit for processing waste biomass and microalgae using silicon carbide (SiC) as a microwave absorber. High heating rates were observed, the heated biomass and the volatiles were removed from the reactor almost instantaneously. A maximum bio-oil yield of 65% and 64% was obtained for wood sawdust and corn stover, respectively. The same system was used to test the catalytic fast pyrolysis. Microalgae were processed with and without the presence of HZSM-5. Yields of 57% and 59% of bio-oil were achieved for Chlorella sp. and Nannochloropsis, respectively. Higher yields of bio-oil were observed compared to the literature. These results suggest that the concept of fast microwave-assisted pyrolysis is technically feasible, requiring further studies to demonstrate its economic viability.
34
Saghir, Muhammad. "A novel pyroformer system for biomass intermediate pyrolysis with in-situ char-promoted reforming (by char re-circulation) of pyrolysis vapours and potential integration of pyroformer with commercial scale fluidised bed gasifier to enable pyrogasification." Thesis, Aston University, 2018. http://publications.aston.ac.uk/37694/.
Full textAbstract:
Strong scientific evidence shows that anthropogenic greenhouse gas emissions from usage of fossil fuels are responsible for global warming and climate change. Biomass is a sustainable and reliable resource for replacing fossil fuels to produce energy and chemicals through pyrolysis and gasification routes. Pyrolysis of biomass leads to three products i.e. bio-oil, non-condensable gas and char. Gasification of biomass leads to a syngas which consists of hydrogen, carbonmonoxide, carbon dioxide, ,methane, nitrogen water vapour and some C1-C4 gases. The objectives of this thesis included: to conduct tests on a twin-screw pyrolysisreactor (Pyroformer); to evaluate the effects of char recirculation on products; to characterise the bio-oil and char produced and characterise an in-situ blend of biodiesel/bio-oil; and to review the design of the Pyroformer and its coupling with a bubbling fluidised bed gasifier, thus enabling a novel concept of Pyrogasification. To observe the biomass and char flow characteristics, and to calculate the residence time and char to biomass ratio (C/B), cold flow tests were performed ina transparent model of 20 kg/h Pyroformer. Biomass throughput limitations were identified at different feeding rates and C/B.Pyrolysis tests were conducted in a Pyroformer with up to 10 kg/h feeding rates. It was observed that, during pyrolysis of dry digestate pellets, gas yield increased and liquid yield decreased at optimum C/B of 3.1 at 5 kg/h. The organic phase ofbio-oil for MSW had an HHV of 30.3 MJ/Kg and a very low total acid number of 0.2mgKOH/g. ENPlus certified wood pellets and miscanthus pellets were pyrolysed in a 100 kg/h Pyroformer with in-situ blending of bio-oil with biodiesel. Product yield of 21, 32and 47 wt% for liquid, char and gas fractions were observed for wood pellets; and31, 32 and 37 wt% with miscanthus. Bio-oil content in the blend was 19.75 and11.28 wt% for wood and miscanthus derived feed stocks. The heavy metal content in biochars met voluntary biochar standards for soil remediation. A gasifier commissioning test was done with hydrogen, CO, methane and CO2 yields of 13.3,17.3, 4 and 17 vol% at 818 °C.
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Rasol, Hepa. "Influence of Potassium on Gasification Performance." Thesis, Högskolan i Borås, Akademin för textil, teknik och ekonomi, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-10350.
Full textAbstract:
To release energy from chemically stored energy in the biomass was the new investigation in recent years. Utilizing of biomass for this purpose occur in two different ways, directly by burning (combustion) the biomass and indirectly by pyrolysis process which will convert the biomass to three main products, bio- tar, bio- char and synthetic gas. Biomass contains different amount of inorganic compound, especially alkali metals which causes some diverse impacts on combustion, pyrolysis and gasification process such as corrosion, agglomeration and fouling problems. This project aims to investigate the effect of K2CO3 on the pyrolysis and gasification processes of three different types of fuel; wood pellets, forest residue pellets and synthetic waste pellets at three different temperatures, 750 °C, 850 °C and 900 °C respectively. The purpose of this work to study and clarify the influence of K2CO3 on char yield, tar yield and tar compositions and the gasification rate and the reactivity of different fuels char. The pyrolysis process was carried out in a fluidized bed reactor during 2 minutes and the products were tar, char and synthetic gas. In this project interested in char and tar only. Char yield calculated and the results shows the char yield increase with increasing of [K2CO3]. While the tar analysis carried on GC- MS instrument at HB to study the tar yield and compositions. The results showed that potassium carbonate has not so much effect on tar yield and its composition. The last part was gasified the char in TGA with steam and CO2 as oxidizing media to study the influence of [K2CO3] on gasification rate and the reactivity of char samples at different temperatures. The result showed the [K2CO3] has inhibitory effect on gasification rate and the reactivity.
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Hsu, Chen Pei, and 許晨霈. "A study of rice husk fast pyrolysis in a bubbling fluidized bed pyrolyzer." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/03296721485500609001.
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Swart, Stephen David. "Design, modelling and construction of a scalable dual fluidised bed reactor for the pyrolysis of biomass." Diss., 2012. http://hdl.handle.net/2263/29849.
Full textAbstract:
The pyrolysis of biomass is a thermochemical process in which woody biomass is converted to several high-value products such as bio-oil, bio-char and syngas. The forestry sector has shown particular interest in this process as a large quantity of biomass is produced as an underutilised by-product in this sector annually. Dual fluidised beds (DFBs) have been identified as a feasible reactor system for this process. However, little attention has been given to the optimisation or to the design of a scalable DFB for the pyrolysis of biomass process. Therefore, the objective of the current project was the design, modelling and construction of a scalable dual fluidised bed system for the pyrolysis of biomass. In order to achieve this objective, several tasks were performed, which included the following: - A literature study was done in order to obtain a theoretical foundation for the current project.
- A novel dual fluidised bed reactor system was designed, which included the block flow diagram and the process and instrumentation diagram for the system.
- A cold unit of the system was built in order to test the performance of the system.
- A comprehensive model for the system was developed, which included mass and energy balance considerations, hydrodynamics and reaction kinetics.
- A complete pilot-scale system of the proposed design was built and tested at the University of Pretoria.
- The current research offers the opportunity for the forestry sector to shift its focus from the production of traditional wood products, such as pulp and paper, to products such as specialised chemicals.
- The bio-oil produced in the dual fluidised bed system can be upgraded to renewable liquid fuels, which may help reduce the dependence of the infrastructure on fossil fuels.
- The dual fluidised bed system provides an opportunity for capturing and removing CO2 from the atmosphere in the form of bio-char. It is therefore considered to be a carbon-negative process, and may help reduce the concentration of greenhouse gases.
- The bio-char produced in the dual fluidised bed system can be used to feed nutrients back to plantation floors in the forestry sector, thereby aiding the growth of further plantations.
Dissertation (MEng)--University of Pretoria, 2013.
Chemical Engineering
unrestricted
38
Grobler, Arthur Bachelor Lofté. "Scalable dual fluidised bed system for fast pyrolysis of woody biomass." Diss., 2015. http://hdl.handle.net/2263/43758.
Full textAbstract:
Pyrolysis of biomass is the thermochemical conversion process whereby the long lignocellulosic
polymers in biomass are cracked into several higher-value products such as bio-oil, bio-char and
combustible non-condensable gases (NCG). Fast pyrolysis in particular is aimed at maximising the
yield of crude liquid bio-oil, with the production of bio-char and NCG as co-products. Since a large
quantity of under-utilised biomass is produced in the forestry sector annually, as by-product from
harvesting, this sector has shown particular interest in this process. Furthermore, the continuing drive
for renewable and sustainable energy production, particularly of drop-in liquid biofuels, has urged the
development of such technology on a commercial scale. The main purpose of this investigation was
to evaluate the technical feasibility and performance of the scalable dual fluidised bed (DFB) reactor
system designed and constructed at the University of Pretoria by Swart in 2012. The sub-objectives
of this study were as follows:
• Biomass pre-treatment equipment was implemented to ensure that the physical
characteristics of the biomass feedstock meet the pyrolysis process requirements.
• The scalable DFB reactor system, including all sub-systems and ancillary equipment, was
commissioned to ensure satisfactory operation of the complete system.
• Continuous, steady-state experimental runs were conducted to produce fast pyrolysis
products in the scalable DFB reactor system.
• The fast pyrolysis products were quantified and characterised to evaluate the technical
feasibility of the DFB reactor system.
• A material and energy balance was conducted over the pyrolysis fluidised bed (PFB) reactor
to quantify its performance.
Eucalyptus grandis raw material, as received from Sappi Southern Africa’s Ngodwana mill, was
successfully converted to bio-oil, bio-char and NCG in the scalable DFB reactor system. Fast
pyrolysis was conducted at a pyrolysis temperature of 500 °C, a vapour residence time of 4 s and a
sawdust feed rate of 2.0 kg/h. The PFB reactor temperature could be controlled easily, at the desired
setpoint (500 °C), by continuously circulating hot solids between the two bubbling fluidised beds. The
excellent temperature control of the PFB reactor makes the DFB system a suitable reactor system for
the fast pyrolysis of biomass on a commercial scale. At these PFB reactor conditions the yield of fast pyrolysis products, on a dry feedstock basis, was
determined as 36.3, 14.0 and 49.7 weight % for bio-oil, NCG and bio-char respectively. High-value
process heat, in the form of hot flue gas (450–500 °C), was produced in the combustion fluidised bed Although the crude liquid bio-oil contained highly oxygenated compounds (including organic acids,
water, alcohols, esters, sugars, aldehydes, ketones, furans, pyrans and phenolics) it may be utilised
for heat generation when co-fired with conventional fossil fuels, including heavy furnace oil. However,
the scalable DFB reactor system allows for integrated catalytic fast pyrolysis, which would enable
catalytic cracking of the biomass feedstock, and the subsequent pyrolysis vapours, to selectively
produce deoxygenated bio-oil compounds, compatible with conventional refinery streams.
The DFB reactor system allowed easy separation of bio-char from the pyrolysis vapours by means of
the bio-char cyclone. The bio-char had a high heating value of only 17.0 MJ/kg because of an
unexpectedly high inorganic content of 54.4 weight % on a dry basis. However, 77.0 weight % of the
inorganics were identified as entrained silica sand fines. Notwithstanding the entrained silica fines,
the bio-char carbon content was determined as approximately 55 weight % on a dry basis, which
would result in a high heating value of approximately 29 MJ/kg. Combustible NCG (including carbon
monoxide, methane, ethane, ethylene, acetylene and propene) were produced as co-product from
the fast pyrolysis of E. grandis sawdust in the DFB reactor system. The high heating value of the
NCG was estimated at 7.3 MJ/kg or 8.3 MJ/Nm3
. Furthermore, it was demonstrated that both the
solid bio-char residue and NCG could be combusted in the CFB reactor to supplement its energy
demand. At the sawdust feed rate of 2 000 g/h and silica sand circulation rate of 50 kg/h, the production rate of
pyrolysis products was estimated at 687.8, 265.2 and 940.0 g/h for bio-oil, NCG and bio-char
respectively. However, only 13.0 g/h of bio-char was collected from the bio-char cyclone, with the
balance (i.e. 927.0 g/h) understood to have been transferred to the CFB with the silica sand heat
carrier. The recycle rate of the NCG was determined as 7 689.7 g/h. The total energy input from the
feedstock and recycled NCG was determined as 150 W, while the energy supplied to the PFB by
means of the hot silica sand was determined as 3 889 W. The pyrolysis reaction energy demand, at
the feed rate of 2 000 g/h, was determined as 1 000 W. The pyrolysis reactor freeboard temperature
was found to be much lower than the fluidised bed temperature (± 195 °C vs. ± 500 °C) as a result of
heat loss. Therefore, the energy output from the pyrolysis products was determined as only 344 W.
The overall heat loss from the PFB reactor was estimated at a very high 2 696 W, which implies that
approximately 69% of the total energy supplied to this reactor by means of the hot silica sand was
dissipated to the surrounding atmosphere. From a heat loss evaluation, it was concluded that the
biomass throughput could be increased by as much as five to ten times by mitigating the heat loss.Dissertation (MEng)--University of Pretoria, 2015.
Chemical Engineering
MEng
Unrestricted
39
Lee, Ying Tso, and 李盈作. "Pyrolysis of Polyethylene and Polypropylene in a Fluidized Bed." Thesis, 1994. http://ndltd.ncl.edu.tw/handle/19853088356384125106.
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碩士逢甲大學
化學工程研究所
82
While growing numbers of plastic waste creating disposal problem,the recycling of plastic waste is getting important topic. The major plastic waste in Taiwan are LDPE,HDPE,PP,PVC, PS,and ABS.The amount of plastic is about one million tons per year and 410,000 tons of total plastic waste may recycle,reuse ,or resourse. From energy view point,it is also evident that the pyrolysis make plastic waste more resources recovery than the others,such as combustion,landfill ,...etc.. The experimental work was carried out in a bubbling fluidized bed which consist of a perforated distributor,and with a stainless column of 100cm bed height(10cm ID),and 100 cm in freeboard(25 cm ID). The polyethylene and the polypropylene are converted into gas,oils,and char by pyrolysis in various temperature and two different catalysts. The experimental temperature was controlled initially by electrical heating,then by autothermal reaction.The autothermal pyrolysis is a physical and chemical conversion process. According to the selected operating parameters,the conversion proceeds either by gasification,by liqquefaction, or by combustion. In this study we found that the product compostion was affected by temperature,heating rate, airfactor and catalyst.
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Chiou, Yue-Han, and 邱約翰. "Fast Pyrolysis of Woody Biomass in a Fluidized Bed." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/30052670536754692760.
Full textAbstract:
碩士國立中興大學
森林學系所
98
Fast pyrolysis is a thermochemical process in which biomass is rapidly heated in the absence of oxygen. Fast pyrolysis of biomass is one of the most promising technologies for converting biomass into liquid fuels. In this study, a 30 kWth bubbling fluidized bed reactor operating with an inert atmosphere was employed to produce bio-oils from the woody biomass such as Dimocarpus longan and Swietenia macrophylla. The kinetics of the pyrolysis of woody feedstocks using thermogravimetric analysis were examined. Also the effects of operating conditions, such as superifical gas velocity, feeding rate, pyrolysis temperature, freeboard temperature and temperature of cooling water on the bio-oil yield from fast pyrolysis of woody feedstocks with/without bark were investigation. The results show that the activation energy of Dimocarpus longan and Swietenia macrophylla are 48.70 kJ mol-1 and 56.23 kJ mol-1, respectively. The bio-oil yield increased with decreasing the gas velocity and freeboard temperature, but with increasing the feeding rate. The optimal pyrolysis temperature for the production of bio-oil was 500oC, and the highest bio-oil yield is 36.91 wt.%. However, The bark of woody biomass would lower the bio-oil yield. In addition, the water content of bio-oil increased with increasing the pyrolysis temperature. Moreover, the HHV on dry basis of bio-oil is between 34-49 MJ kg-1, and the char yield is about 24 wt.%. It can also be found that the yields of syngas, CO and CH4, increased with increasing the pyrolysis temperature, but CO2 content shows the contrary results.
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Jyun-JchinJhan and 詹峻智. "system development and product analysis for the fluidized bed fast pyrolysis." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/gp4x24.
Full textAbstract:
碩士國立成功大學
航空太空工程學系
105
In this study, both system development and experimental investigation were conducted for fluidized bed fast pyrolysis. The design of a fluidized bed pyrolysis system, including a fluidized bed reactor, a feeder, a cyclone and a condenser, was carried out in order to improve the system performance and efficiency. Rice husk was chosen as the feedstock based on its availability in Taiwan. The product distributions from fluidized bed pyrolysis were studied with varying temperature, carrier gas flow rate and biomass feeding. The results showed that the optimal experimental conditions for obtaining the maximum bio-oil yield were at the temperature between 400 ℃ and 450 ℃ , the flow rate of 45 L /min and biomass feeding of 21.3 g per inject time. The analysis of GC-MS indicated that the major components of bio-oil contain n-hexadecanoic acid, octadecaoic acid, 9-octadecenoic acid and decanoic acid. The element and property analysis of bio-oil demonstrated that the bio-oil has high oxygen content and low heating value. The analysis of GC-TCD showed that the major components of non-condensable gas are CO2, H2, CH4 and N2.
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Firdaus, Ahmad Hanif, and 歐識賢. "Fast Pyrolysis of Palm Kernel Shell Biomass in Fluidized Bed Reactor." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/g6t9ga.
Full textAbstract:
碩士國立中央大學
機械工程學系
102
ABSTRACT In this thesis, palm kernel shell (PKS) biomass are pyrolyzed in a fast pyrolysis system using fluidized bed reactor and ceramic balls as fluidizing medium, with CO2 as fluidization gas. The purpose of this research is to find the effect of operating parameters, such as reactor temperature (350º - 550ºC), fluidizing gas flow rate (5-15 liter/min) and heating rates (1, 5, 10 K/min) on the yield of each pyrolysis product (bio-oils, gas, and char). The composition of PKS biomass and their product are investigated according to ASTM (American Society for Testing and Materials) standard methods. The result shows that the maximum bio-oil yield is 20.4 wt.%, occurred at 500ºC and the flow rate of CO2 is 10 liter/min, the other product are char with 36.0 wt.% and gas with 43.6 wt.%. Char decreases with increasing reactor temperature and CO2 flow rate. A opposite, the gas product increases with increasing reactor temperature and CO2 flow rate above 10 liter/min. From TG (thermogravimetry) and DTG (differential thermogravimetry) analysis, the weight loss are generally divided into 3 parts. First, occurred from 100ºC to 220ºC, presented the moisture and extractive evaporations. The second weight loss occurred at 240ºC - 400ºC, the thermal decomposition of cellulose and hemicellulose and the third, the weight loss above 400ºC until 900ºC is mainly due to the decomposition of lignin. The DTG curves have two peaks. The first peak is assigned to devolatilization of hemicellulose, while the second peak is cellulose. The effects of the heating rate on the DTG curve and maximum decomposition rate are investigated. At higher heating rates, individual conversions are reached at higher temperatures. For the heating rate of 1 K/min, the first and second peak occurred at 280 ºC and 380ºC. For 5 K/min, they occurred at 305 ºC and 390 ºC. They occurred at 310 ºC and 405 ºC for 10 K/min. The maximum of the decomposition rate is also slightly shifted towards higher temperature. CHNO content of bio oils are 67.70 wt.%, 9.70 wt.%, 0.90 wt.%, and 21.70 wt.%, respectively. Bio-char have high carbon content, around 62.87 wt.%, other elemental compositions are 2.54 wt.% of hydrogen, nitrogen with 0.56 wt.%, 0.01 wt.% for sulfur, and oxygen with 10.80 wt.%. Proximate analysis of PKS bio char gets 23.18 wt.% of ash, 3.30 wt.% of moisture, also HHV, volatile matter, and fixed carbon with 23.56 MJ/kg, 17.86 wt.%, and 58.96 wt.%, respectively. When using CO2 utilized as fluidization gas, the gas product has compositions similar to previous study, and consists mostly of CO2 (Over 50 vol.%), followed by CO, and little amount of CH4 and H2. Keywords: Biomass, palm kernel shell, fast pyrolysis, bio-oil
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Luo, Cheng Xin, and 駱呈欣. "Operating parameters of autothermal pyrolysis of plastic waste in a fluidized bed." Thesis, 1994. http://ndltd.ncl.edu.tw/handle/07044592163214159701.
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Jalalifar, S. "Operational management of fast pyrolysis process using numerical modelling." Thesis, 2020. https://eprints.utas.edu.au/35036/1/Jalalifar_whole_thesis.pdf.
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Depletion of fossil fuels and their environmental impacts such as global warming and climate change are strong motivations for developing alternative energy sources. However, the transition from petroleum-based to renewable infrastructure is challenging. Some of the determining factors to be looked upon of these challenges include but certainly do not restrict only to established fossil fuel infrastructures, availability, viability and economical-feasibility of adequate and appropriate technologies. Bio-based fuels can provide a bridging/alternative to petroleum fuels due to similarity in physical and thermal properties and abundant biomass feedstock. Pyrolysis process; which is an oxygen-free thermal decomposition process is a promising route to convert raw biomass into high-energy-density bio-oil and combustible gases. Pyrolysis can be broadly categorised into three types according to temperature and residence time/heating rates; slow, fast, and flash pyrolysis. The highest bio-oil yield is associated with fast pyrolysis (50–75 wt%).
Fluidised bed reactor and auger reactor are the most attractive technologies and feasible options for scale-up. Although the experimental test is inevitable for process optimisation and scale-up, computational fluid dynamics (CFD) is a powerful tool for the study of the processes that operate in severe conditions, e.g. high temperature and pressure. In such circumstances, numerical simulation is a much more feasible and affordable approach than experimental tests for parametric study. This study aims to implement a numerical framework to simulate the process that can be used as a design tool; determine the critical operating conditions for process optimisation and scale-up of the pyrolysis reactors; determine the range of conditions for the highest amount of bio-oil yield, and use these results to optimise the lab-scale bubbling fluidised bed reactor and a pilot-scale auger unit.
This thesis presents the CFD simulation of a fast pyrolysis process in a two-dimensional standard lab-scale bubbling fluidised bed reactor. In the CFD model, the Eulerian-Granular approach is adopted to address the multi-phase fluid dynamics of the fast pyrolysis processes. A coupled Multi-Fluid Model (MFM) and a chemical solver is used to describe the chemical kinetics. The developed model is validated first using published experimental data then implemented to a parametric study. The impact of different operating factors on the product yields is then presented. The operating conditions are operating temperature, biomass feedstock, biomass feed rate and size, sand particle size, carrier gas velocity and biomass injector location. The results showed that the optimum value of operating temperature is in the range of 500–525 °C. The residence time and secondary reactions can be minimised by increasing the speed of the carrier gas and raising the location of the biomass injector. The intraparticle temperature gradient is lower for smaller biomass particles which resulted in higher heating rates. When larger sand particles are accompanied by higher carrier gas velocity, bio-oil yield increased. Preheating the virgin biomass improves bio-oil yields, whereas other products’ yields remain constant. The feedstocks with high cellulose/hemicellulose to lignin ratio are favourable for the production of bio-oil, whereas the highest amount of biochar yield was achieved from high lignin-content feedstocks.
A three-dimensional computational fluid dynamic (CFD) model for simulation of a fast pyrolysis process in a pilot-scale auger reactor is also conducted. The adopted methodology used in the CFD simulation of auger reactor is similar to the bubbling fluidised bed reactor. However, the geometry of the auger reactor is more complicated than that of the bubbling fluidised bed reactor and needs to be modelled in a three-dimensional space. Furthermore, the rotating reference frame (RRF) is adopted to simulate the effect of the rotating screw in the auger reactor to avoid the complexity of dynamic mesh generation. The simulation results were compared with the experiment, and the effects of operating conditions were investigated. A parametric study was then conducted to address the effect of operating parameters on the product yields. The results indicate that the optimum temperature for maximum bio-oil production is 500°C. Bio-oil yield rose as the biomass feed flow rate increased due to less vapour residence times, reducing further reaction of the non-condensable fraction in the vapour phase. Nitrogen shows the same impact, enhanced yield due to limited vapour residence time. Increasing the angular velocity of the screw improves the flow of vapours in the reactor. However, this must be balanced against increased unreacted biomass. The simulation gave an optimum of 70rpm for the angular velocity of the screw.
The validated CFD model for bubbling fluidised bed reactor is employed to find an optimised set of operating conditions to achieve the highest amount of bio-oil yield. The CFD parametric study was conducted by considering the effect of the key influencing parameters. Machine learning algorithms (MLAs) are then employed to predict the optimised conditions that lead to the maximum bio-oil yield. A developed support vector regression with particle swarm optimisation algorithm (SVR-PSO) was applied to the CFD datasets to predict the optimum values of parameters. The highest bio-oil yield was then computed using the optimum values of the parameters. The CFD simulation is also conducted using the optimum parameters obtained by the SVR-PSO. The obtained CFD results and the predicted values by MLA compared and a good agreement was achieved.
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MOUDGALYA, KANNAN MANI. "EFFECTIVE DIFFUSIVITIES IN CHAR PARTICLES (DIFFUSION, FAST FOURIER TRANSFORM, PYROLYSIS, COAL, FLUIDIZED BED)." Thesis, 1985. http://hdl.handle.net/1911/15925.
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Illinois #6, Illinois #5, Pittsburgh #8 coal and Texas Lignite particles of size range 150-16 mesh were pyrolyzed at a heating rate of 3.8 K/min up to 900(DEGREES)C. A stainless steel annular fluidized bed reactor yielded unagglomerated char particles. On-line analysis of the low molecular weight gaseous effluents was performed using a Series-Bypass column arrangement. The effluent profiles were in agreement with previous results.
The char particles were gasified with oxygen in the annular fluidized bed reactor and with CO(,2) in a U tube spouted bed reactor. In both cases, the on-line analysis of the effluent gases helped determine the conversion of char.
The transient pulse chromatography method was chosen to measure the macro pore effective diffusivities in Illinois #6 and Texas Lignite char particles reacted with oxygen. For a known pulse of helium into a Single Pellet String Reactor packed with char particles, the output chromatogram was measured as discrete data. Using the Kubin-Kucera model, the output profile was predicted also in discrete form in the Fourier domain. The residuals, the (,2) norms of the differences between the model predictions and the experimental observations, were minimized to extract the model parameters. The COMPLEX optimization procedure and an intelligent search scheme were used for this purpose. This is the first time the Discrete and Fast Fourier Transform techniques have been used to extract the model parameters. The intelligent search scheme is another novelty of this work.
The diffusivities increased linearly with porosity for the reacted Illinois #6 and Texas lignite char. The tortuosity factor was found to be about 75 for the reacted Illinois #6 char and about 175 for Texas Lignite char. It was not possible to determine the diffusivity values for the unreacted Illinois char.
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Tseng, Cheng-Wei, and 曾正偉. "Fast pyrolysis of rice husks in a fluidized-bed for bio-oil production." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/vj34qp.
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碩士國立中央大學
能源工程研究所
105
The research can be discussed in two aspects, including fluidizing condition-liquid yield and pyrolysis condition-chemical analysis. Firstly, the main factor that affects minimum fluidizing velocity (umf) is particle size. When gas velocity falls on 2.33 umf, average oil yield is about 20wt.% which is better than other values, and the pH value is higher, which means bio-oil is hard to second-react with acidic matters in it. Temperature doesn’t have many things to do with fluidizing pressure drop as the value of each size keeps the same; When particle size falls on 0.40mm, there is the best yield of all, 32.18 wt.%. And carbon conversion rate is also higher as acidity is weaker. C, H, O three elements take the majority in bio-oil. For C, is about 20wt.%, for H, is about 10-15wt.%, for the rest part is O as N and S are very few. Secondly, at 500℃, there are higher oil-yield of 23wt%-32wt%, and so as HHV, the best one is 7254.1kcal/kg. And acidity is weaker while conversion rate is better. For the reason that TGA analysis models of biomass in heating mode have been set up by some researchers while isothermal mode haven’t and needs shorter time to reach steady temperature, this research use isothermal mode to test the thermal-gravimetric loss of biomass observe the properties of pyrolysis, and calculate the pyrolysis dynamic parameters. The chemicals that have apparent area concentration in bio-oil are Acetic anhydride, 1,2-benzenediol, 2-methylphenol and phenol. Finally, consider those correlation coefficients, the fluidizing pressure drops are negatively related to oil yields. When pressure drops get smaller, closer to 2 umf, the oil yields get higher, which means that the minimum bubbling velocity, umb, is quite close to 2umf ; In chemicals contained in the oil, 2-hydroxyl-3-methyl-2-cyclopenten-1-one is dominant in carbon content, HHV and pH value, and is positively related to them; Meanwhile, acetic anhydride and toluene are negatively related to carbon content, HHV, carbon conversion rate; 4-methylphenol is highly positively related to carbon conversion rate.
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Chang, Ching Houng, and 張錦煌. "Recycling of Scrape Tires to Oil and Carbon Black by Pyrolysis in a Fluidized Bed." Thesis, 1994. http://ndltd.ncl.edu.tw/handle/58904883617818651905.
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碩士逢甲大學
化學工程研究所
82
With growing number of car and motorcycle, waste tire re- cycling has become a necessity because of the huge piles of tires that represent a threat to the environment. The used tires represent a source of energy and valuable chemical pro- ducts. Pyrolysis can make tires a decent fuel for utilities. Comparing with incineration, landfill and retreading, pyrolysis is a more suitable and economical way to deal with used tires. In our experiments,a laboratory-scal fluidized bed was used to pyrolysis scrapp tires,controlled by limited air supply. For searching the best operational condiction, bed material size, feed material size,and gas velocity were concerned. the compo- sitions and properties of the pyrolytic oils and solid were de- termined in relation to pyrolysis temperatureup up to 843K. The experimental work was carried out initially by electrical heating, then by autothermal reaction. The experimential results was found that without external heating, pyrolysis could carry out by partial combusition and auto thermal cracking, temperature was affected by airfactor, temperature had a significant influence on the composition of products, and the yield of gasoline was affected by zeolite. The scrap tires produced approximately 29% oil,16% gas,20% char 15% water .
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Chiu, Cheng-wei, and 邱正瑋. "Fabrication of nano-TiN powder by pyrolysis conversion of TiO2 in a fluidized bed furnace." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/06311054698068321555.
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碩士大同大學
材料工程學系(所)
92
Nano-structure TiN powders were prepared by using anatase-TiO2 and graphite mixtures as the precursor. Prior to thermal conversion, the mixture of TiO2 and graphite was milled in a high energy attritor to enhance the validity of carbothermic reduction. The nano-TiN powders were thermal converted by introducing N2 into a low pressure circulated fluidized-bed reactor which was previously evacuated to the pressure around 10-1 torr The formation of TiN compound is greatly enhanced by high-energy milling due to the reduced crystallite size, large grain boundary area, presence of amorphous phases and the increased defect concentration in the powder reactants given by the high-energy milling. Crystallites size of the powder mixtures decreased as increasing of milling time. The nano-TiN formation can be accomplished at a relatively low reaction temperatures and short reaction time via severe milling of TiO2 + graphite mixtures. The experiment results evidenced that the carbothermic reduction could not be occurred if the powder mixture of TiO2 + graphite had not been undergone a severe milling
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SUARSANA, PURNA ANUGRAHA, and 安普納. "ANALYSIS OF FAST PYROLYSIS PHENOMENA IN FLUIDIZED BED REACTOR OF PALM KERNEL SHELL (PKS) BIOMASS." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/08981004855078481402.
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碩士國立中央大學
機械工程學系
102
The fast pyrolysis phenomena in fluidized bed reactor of Palm Kernel Shell such as the effect of temperature fluidization gas, velocity fluidization gas and mass flow rate of biomass on product yield of fast pyrolysis PKS biomass were investigated based on the Euler-Euler approach in this work. The temperature of fluidization is varied of 723, 743 and 763K. The velocity of fluidization gas is varied of 0.059, 0.088 and 0.117 m/s. The mass flow rate is varied of 2.42, 3.63 and 4.84 g/s. Result of CFD simulation studies is: the temperature of fluidization gas, velocity of fluidization gas and mass flow rate of biomass is effect on product yield of fast pyrolysis PKS Biomass. The increasing temperature of fluidization gas is lead to increasing of mass fraction tar and decreasing of mass fraction char and gas. At temperature 763K, the mass fraction of tar is 49.26%, mass fraction of char and gas are 27.78% and 22.96%. The increasing velocity of fluidization gas is lead to increasing tar and decreasing mass fraction of char and gas until velocity of 0.088m/s, after that the trend of product yield fast pyrolysis is vice versa. At velocity 0.088m/s, the mass fraction of tar, char and gas are 50.09%, 27.06% and 22.86%. The increasing mass flow rate of biomass is lead to increasing the mass fraction of tar and decreasing mass fraction of char and gas. At the mass flow rate 4.84 g/s, the mass fraction of tar, char and gas are 50.36%, 26.89% and 22.77%. Keywords: Fast pyrolysis, PKS biomass, fluidized bed, product yield
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An-ChengLee and 黎安成. "Fluidized Bed Fast Pyrolysis of Miscanthus and Hydro-processing for Upgrading the Produced Bio-oil." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/37ak8z.
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