Tesi sul tema "Entrained flow coal gasification"
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Alonso, Lozano Alvaro. "Coal gasification in entrained flow gasifiers simulation & comparison". Thesis, Högskolan i Gävle, Avdelningen för bygg- energi- och miljöteknik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-12726.
Testo completoRAKHSHI, AALIA. "A COMPUTATIONAL STUDY OF DEVOLATILIZATION AND KINETICS IN ENTRAINED FLOW COAL GASIFICATION". OpenSIUC, 2018. https://opensiuc.lib.siu.edu/dissertations/1534.
Testo completoSilaen, Armin. "Comprehensive Modeling and Numerical Investigation of Entrained-Flow Coal Gasifiers". ScholarWorks@UNO, 2010. http://scholarworks.uno.edu/td/1148.
Testo completoLu, Xijia. "An Applied Numerical Simulation of Entrained-Flow Coal Gasification with Improved Sub-models". ScholarWorks@UNO, 2013. http://scholarworks.uno.edu/td/1696.
Testo completoYoung, Christopher Michael. "Pressure Effects on Black Liquor Gasification". Diss., Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/11539.
Testo completoDuchesne, Marc A. "Slagging in Entrained-flow Gasifiers". Thèse, Université d'Ottawa / University of Ottawa, 2012. http://hdl.handle.net/10393/23353.
Testo completoKumar, Mayank Ph D. Massachusetts Institute of Technology. "Multiscale CFD simulations of entrained flow gasification". Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/69495.
Testo completoCataloged from PDF version of thesis.
Includes bibliographical references.
The design of entrained flow gasifiers and their operation has largely been an experience based enterprise. Most, if not all, industrial scale gasifiers were designed before it was practical to apply CFD models. Moreover, gasification CFD models developed over the years may have lacked accuracy or have not been tested over a wide range of operating conditions, gasifier geometries and feedstock compositions. One reason behind this shortcoming is the failure to incorporate detailed physics and chemistry of the coupled non-linear phenomena occurring during solid fuel gasification. In order to accurately predict some of the overall metrics of gasifier performance, like fuel conversion and syngas composition, we need to first gain confidence in the sub-models of the various physical and chemical processes in the gasifier. Moreover, in a multiphysics problem like gasification modeling, one needs to balance the effort expended in any one submodel with its effect on the accuracy of predicting some key output parameters. Focusing on these considerations, a multiscale CFD gasification model is constructed in this work with special emphasis on the development and validation of key submodels including turbulence, particle turbulent dispersion and char consumption models. The integrated model is validated with experimental data from various pilot-scale and laboratory-scale gasifier designs, further building confidence in the predictive capability of the model. Finally, the validated model is applied to ascertain the impact of changing the values of key operating parameters on the performance of the MHI and GE gasifiers. The model is demonstrated to provide useful quantitative estimates of the expected gain or loss in overall carbon conversion when critical operating parameters such as feedstock grinding size, gasifier mass throughput and pressure are varied.
by Mayank Kumar.
Ph.D.
Rasid, Ruwaida Abdul. "Modelling and simulation of entrained flow gasification processes". Thesis, University of Leeds, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.595675.
Testo completoGibbs, Laura Anne. "Coal devolatilization in an entrained flow reactor". Thesis, University of Ottawa (Canada), 1989. http://hdl.handle.net/10393/6029.
Testo completoJoyce, James Alexander. "Pressurised entrained flow gasification of sugar cane wastes for cogeneration /". [St. Lucia, Qld.], 2006. http://adt.library.uq.edu.au/public/adt-QU20060713.095935/index.html.
Testo completoHägglund, Philip. "Commissioning of Entrained Flow Reactor for Combustion and Gasification Research". Thesis, Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-66204.
Testo completoCarlsson, Per. "Entrained flow black liquor gasification : detailed experiments and mathematical modelling". Licentiate thesis, Luleå : Luleå university of technology, 2009. http://pure.ltu.se/ws/fbspretrieve/3076792.
Testo completoTremel, Alexander [Verfasser]. "Reaction Kinetics of Solid Fuels during Entrained Flow Gasification / Alexander Tremel". München : Verlag Dr. Hut, 2013. http://d-nb.info/1031843787/34.
Testo completoMa, Charlie. "Slag Formation During Pilot-Scale Pressurised Entrained-Flow Gasification of Woody Biomass". Licentiate thesis, Luleå tekniska universitet, Energivetenskap, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-18723.
Testo completoGodkänd; 2014; 20141102 (chamaf); Nedanstående person kommer att hålla licentiatseminarium för avläggande av teknologie licentiatexamen. Namn: Charlie Ma Ämne: Energiteknik/Energy Engineering Uppsats: Slag Formation During Pilot-Scale Pressurised Entrained-Flow Gasification of Woody Biomass Examinator: Professor Marcus Öhman, Institutionen för teknikvetenskap och matematik, Luleå Tekniska universitet Diskutant: Universitetslektor Christoffer Boman, Umeå Universitet Tid: Fredag den 12 december 2014 kl 10.00 Plats: E246, Luleå tekniska universitet
Mackrory, Andrew John. "Characterization of Black Liquor Sprays for Application to Entrained-Flow Processes". Diss., CLICK HERE for online access, 2006. http://contentdm.lib.byu.edu/ETD/image/etd1593.pdf.
Testo completoJafri, Yawer. "Entrained-Flow Gasification of Black Liquor and Pyrolysis Oil : Experimental and Equilibrium Modelling Studies of Catalytic Co-gasification". Licentiate thesis, Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-60342.
Testo completoLTU Biosyngas (Catalytic Gasification)
Eriksson, Anna-Maria. "Torrefaction and gasification of biomass. The potential of torrefaction combined with entrained-flow gasification for production of synthesis gas". Thesis, KTH, Skolan för kemivetenskap (CHE), 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-146313.
Testo completoLee, Ching Yuan. "Problems involved in simulating the flash carbonization process". Ohio : Ohio University, 1987. http://www.ohiolink.edu/etd/view.cgi?ohiou1183048088.
Testo completoBlanchard, Ryan P. "Measurements and Modeling of Coal Ash Deposition in an Entrained-Flow Reactor". Diss., CLICK HERE for online access, 2008. http://contentdm.lib.byu.edu/ETD/image/etd2376.pdf.
Testo completoDeYoung, Stefan [Verfasser]. "Numerical Simulation of Entrained Flow Gasification with Focus on Char Reaction Kinetics / Stefan DeYoung". München : Verlag Dr. Hut, 2019. http://d-nb.info/1188516086/34.
Testo completoPugalia, Neeraj. "Numerical modeling of cold flow and hot gas desulfurization in a circulating fluidized bed". Morgantown, W. Va. : [West Virginia University Libraries], 2001. http://etd.wvu.edu/templates/showETD.cfm?recnum=2056.
Testo completoTitle from document title page. Document formatted into pages; contains xvi, 119 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 103-106).
Legonda, Isack Amos. "Biomass gasification using a horizontal entrained-flow gasifier and catalytic processing of the product gas". Thesis, Cardiff University, 2012. http://orca.cf.ac.uk/39280/.
Testo completoMa, Charlie. "Aspects of Ash Transformations in Pressurised Entrained-Flow Gasification of Woody Biomass : Pilot-scale studies". Doctoral thesis, Luleå tekniska universitet, Energivetenskap, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-62914.
Testo completoSoncini, Ryan Michael. "Computational Simulation of Coal Gasification in Fluidized Bed Reactors". Diss., Virginia Tech, 2017. http://hdl.handle.net/10919/78733.
Testo completoPh. D.
Fradet, Quentin [Verfasser], e Uwe [Akademischer Betreuer] Riedel. "Novel modeling approaches for the entrained-flow gasification of bio-slurries / Quentin Fradet ; Betreuer: Uwe Riedel". Stuttgart : Universitätsbibliothek der Universität Stuttgart, 2020. http://d-nb.info/1217253424/34.
Testo completoPanday, Rupendranath. "Modeling, identification and control of a cold flow circulating fluidized bed". Morgantown, W. Va. : [West Virginia University Libraries], 2008. https://eidr.wvu.edu/etd/documentdata.eTD?documentid=5833.
Testo completoTitle from document title page. Document formatted into pages; contains xiii, 99 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 94-99).
Wu, Chunyang. "Fuel-NOx Formation during Low-Grade Fuel Combustion in a Swirling-Flow Burner". Diss., CLICK HERE for online access, 2006. http://contentdm.lib.byu.edu/ETD/image/etd1165.pdf.
Testo completoVargas, Duarte Gerardo. "An experimental study of the hydrodynamics of multiphase flow in fluidized beds". To access this resource online via ProQuest Dissertations and Theses @ UTEP, 2009. http://0-proquest.umi.com.lib.utep.edu/login?COPT=REJTPTU0YmImSU5UPTAmVkVSPTI=&clientId=2515.
Testo completoMarklund, Magnus. "Pressurized entrained-flow high temperature black liquor gasification : CFD based reactor scale-up method and spray burner characterization /". Luleå : Division of Fluid Mechanics, Luleå University of Technology, 2006. http://epubl.ltu.se/1402-1544/2006/42LTU-DT-0642-SE.pdf.
Testo completoKestel, Matthias. "Numerical modeling of moving carbonaceous particle conversion in hot environments". Doctoral thesis, Technische Universitaet Bergakademie Freiberg Universitaetsbibliothek "Georgius Agricola", 2016. http://nbn-resolving.de/urn:nbn:de:bsz:105-qucosa-204732.
Testo completoTremel, Alexander [Verfasser], Hartmut [Akademischer Betreuer] Spliethoff e Thomas [Akademischer Betreuer] Kolb. "Reactions Kinetics of Solid Fuels during Entrained Flow Gasification / Alexander Tremel. Gutachter: Hartmut Spliethoff ; Thomas Kolb. Betreuer: Hartmut Spliethoff". München : Universitätsbibliothek der TU München, 2012. http://d-nb.info/1031550658/34.
Testo completoStrandberg, Martin. "From torrefaction to gasification : Pilot scale studies for upgrading of biomass". Doctoral thesis, Umeå universitet, Institutionen för tillämpad fysik och elektronik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-103046.
Testo completoSeptien, Stringel Joël. "High temperature gasification of millimetric wood particles between 800°C and 1400°C". Thesis, Toulouse, INPT, 2011. http://www.theses.fr/2011INPT0125/document.
Testo completoBiomass gasification was studied in the conditions of an entrained flow reactor, namely at high heating rate and temperature. Experiments in a drop tube reactor were performed between 800°C and 1400°C, with wood particles of 0.35 mm and 0.80 mm size, under inert and steam containing - 25 mol% of H2O - atmospheres. These experiments were also simulated with a 1D model which gave good predictions. The collected solids, soot and char, were analyzed and characterized. This study highlights the importance of gas phase reactions on the yields of the final products, mainly gaseous compounds, in these conditions. These reactions are hydrocarbons cracking, reforming and polymerization, leading to soot formation, and water-gas shift. Char graphitization and deactivation were experimentally demonstrated. However, these phenomena have a negligible influence on char evolution in the drop tube reactor. Finally, the particle size was shown to have almost no influence on experimental results
Bayham, Samuel C. "Iron-Based Coal Direct Chemical Looping Process for Power Generation: Experimental Aspects, Process Development, and Considerations for Commercial Scale". The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1425759077.
Testo completoLu, You. "Computational Scheme Guided Design of a Hybrid Mild Gasifier". ScholarWorks@UNO, 2012. http://scholarworks.uno.edu/td/1526.
Testo completoSchrier, Loren Clare. "Identification of by-products and investigation into the dechlorination mechanism of the Chemchar cocurrent flow gasification process by gas chromatography-mass selective detection /". free to MU campus, to others for purchase, 1998. http://wwwlib.umi.com/cr/mo/fullcit?p9904867.
Testo completoTrademark symbol follows Chemchar in title. Typescript. Vita. Includes bibliographical references (leaf 130). Also available on the Internet.
Mazumder, AKM Monayem Hossain. "Development of a Simulation Model for Fluidized Bed Mild Gasifier". ScholarWorks@UNO, 2010. http://scholarworks.uno.edu/td/101.
Testo completoGärtner, Lars-Erik. "Modellierung und Simulation der Vergasung von Brennstoffmischungen". Doctoral thesis, Technische Universitaet Bergakademie Freiberg Universitaetsbibliothek "Georgius Agricola", 2015. http://nbn-resolving.de/urn:nbn:de:bsz:105-qucosa-184350.
Testo completoWithin this document the modeling and simulation of fuel blend gasification is investigated based on a variably applicable Reduced Order Model (ROM) developed for the flowsheet simulation of entrained-flow gasification reactors and processes. On one hand this enables the investigation of cascaded solid fuel conversion technologies and on the other hand effects during gasification of binary and ternary fuel blends are describable. The development as well as the validation of the ROM has been carried out for the SFGT gasifier, the PEFR gasifier and the hybrid-wall gasifier. The subsequent analysis of binary and ternary fuel blend gasification shows that fuel blends with very heterogeneous component properties induce synergy effects which have been reported in various peer review publications
Billaud, Joseph. "Gazéification de la biomasse en réacteur à flux entrainé : études expérimentales et modélisation". Thesis, Ecole nationale des Mines d'Albi-Carmaux, 2015. http://www.theses.fr/2015EMAC0010/document.
Testo completoThe present work deals with biomass gasification in Entrained Flow Reactor (EFR) in the context of the development of new Biomass-to-Liquid processes. The objective of this study is to develop a comprehensive model to better understand the phenomena controlling biomass gasification in conditions representative of an EFR. Biomass pyrolysis and gasification of beech particles sieved between 315 and 450 µm have been studied between 800 and 1400°C in a drop tube furnace. The influence of H2O, CO2 and O2 addition on gasification products has been investigated and the tests have been simulated with a 1D model. The addition of H2O or CO2 leads to a significantly lower char yield. The main influence of these two oxidants in gas phase is the modification of major species composition with water gas shift reaction. With the addition of O2, the carbon conversion into gas is improved and the char and soot yields are significantly lower. The simulations are in very good agreement with the experimental results. Biomass pyrolysis and gasification of beech particles sieved between 1.12 and 1.25 mm have been studied in presence of O2. Between 800 and 1200°C the carbon conversion into gas is lower than with the smaller particles but at 1400°C the particle size has no influence. At last, the influence of O2 addition, particle size and pressure on biomass gasification has been studied in a pilot scale EFR. These experimental results have been satisfactorily simulated by adapting the 1D model
Meillot, Erick. "Contribution a l'etude d'un plasma d'arc de vapeur d'eau : application a la gazeification de charbon pulverise en plasma d'arc". Toulouse 3, 1988. http://www.theses.fr/1988TOU30030.
Testo completoBoigelot, Romain. "Gazéification de déchets organiques dans un réacteur à flux entrainé : impact des inorganiques sur le fonctionnement du réacteur et choix des céramiques réfractaires". Phd thesis, Université d'Orléans, 2012. http://tel.archives-ouvertes.fr/tel-00835075.
Testo completoBeath, Andrew Charles. "Mathematical Modelling of Entrained Flow Coal Gasification". Thesis, 1996. http://hdl.handle.net/1959.13/24844.
Testo completoPhD Doctorate
Beath, Andrew Charles. "Mathematical Modelling of Entrained Flow Coal Gasification". Diss., 1996. http://hdl.handle.net/1959.13/24844.
Testo completoPhD Doctorate
Hong, Mong Yie, e 洪孟逸. "Simulation of coal gasification in entrained-flow bed". Thesis, 1993. http://ndltd.ncl.edu.tw/handle/67925215174649839003.
Testo completoChih-JungChen e 陳致融. "Numerical Simulation and Optimization of Coal and Biomass Gasification in an Entrained-bed Gasifier". Thesis, 2013. http://ndltd.ncl.edu.tw/handle/99171288255043145063.
Testo completo國立成功大學
機械工程學系碩博士班
101
Gasification plays an important role in the development of clean coal technology. In addition, not only coal but also other materials can be employed as feedstocks in gasification. Biomass is an important source of renewable energy in the world. It can also be gasified with coal through co-gasification. Therefore, the objective of this study is to seek appropriate operations for gasification process, the present study develops a numerical method to predict coal gasification phenomena in an entrained-flow gasifier. Particular emphasis is placed on the influence of injection pattern upon synthesis gas (syngas) production. The parameter of steam/coal ratio is also taken into account to evaluate its impact on hydrogen generation. With oxygen injected from the center inlet and coal from the middle ring inlet of the reactor, the operating pattern gives the best performance of coal gasification where the carbon conversion (CC) and coal gas efficiency (CGE) are 89 and 72%, respectively. Increasing steam into the reactor reduces CC and less CO is generated. For the results of gasaification by different feeds, the obtained results suggest that in all cases, the carbon conversions of the three fuels are higher than 90%. However, the cold gasification efficiency for raw bamboo is low, mainly due to the relatively lower calorific value of the material. In the case of the torrefied bamboo fuel, the gasification performance is enhanced significantly and is quite similar to the coal gasification under the same conditions. It appears that the optimum oxygen-to-fuel mass flow ratios for the gasification of raw bamboo, torrefied bamboo, and coal are 0.9, 0.7, and 0.7, and their equivalence ratios are 0.692, 0.434, and 0.357, respectively. On the other hand, Gasification is a very complex thermal conversion process. The result of gasification is influenced by many factors. Hence, the present study was conducted to optimize the gasification process in an entrained-flow gasifier through the application of the Taguchi method. Results suggest that the optimum conditions are a wall temperature of 1500 K, an O/F ratio of 0.6, coal feed type and a gasifier pressure of 3 MPa. The influence strength order of each control condition is feed type>O/F ratio>wall temperature>pressure. The value of the S/N ratio for the optimum case is 13.40, which is the highest value compared to other cases. The simulations suggest that the developed numerical method is able to provide an accurate prediction on syngas formation. With oxygen injected from the center inlet and coal from the middle ring inlet of the reactor, the operating pattern gives the best performance of coal gasification. Analysis of the Taguchi method was used to evaluate the calculation results. Results show that the Taguchi method is able to investigate the gasification process well.
Cheng-RungLei e 雷政融. "Influences of Different Combustion Models on the Coal-Gasification Simulation of an Entrained-Bed Gasifier". Thesis, 2013. http://ndltd.ncl.edu.tw/handle/56615855879415291703.
Testo completo國立成功大學
航空太空工程學系碩博士班
101
In the present study, a numerical model has been developed for an up-flow entrained-bed gasifier by the commercial CFD software, ANSYS-FLUENT. The accuracy for the predicted composition of the outlet syngas and temperature distribution is compared for different turbulent combustion models. Two different combustion models including non-premixed flamelet model, and finite-rate/eddy dissipation model, are investigated. The results obtained from the present computations show that the predicted syngas composition by the finite-rate/eddy dissipation model is in better agreement with the experimental data. However, the concentration of H2 is under-estimated by the non-premixed flamelet model. Regarding the outlet temperature and the temperature distribution, the predictions by the finite-rate/eddy dissipation model are also in better agreement with the experiment. The temperature is overestimated by the non-premixed flamelet model. As far as the carbon conversion and cold gas efficiency are concerned, the predictions by the finite-rate/eddy dissipation model are close to the experimental data, while those by the non-premixed flamelet model are underestimated. On the whole, the finite-rate/eddy dissipation model is superior to the non-premixed flamelet model in the accuracy of predictions.
Pan, Ze-Wei, e 潘則瑋. "Numerical Simulation Study of Gasification Characteristics in Entrained Bed Gasifier with Coal Water Slurry and Bio-slurry". Thesis, 2013. http://ndltd.ncl.edu.tw/handle/27u523.
Testo completo國立虎尾科技大學
機械與機電工程研究所
101
Coal is the largest stock of the fossil fuel around the world, that was about 72%. It content high energy density to own high potential performance of economics. It emitted large amount the pollutions in the coal using process directly, that reduced the competitiveness of coal. Therefore, how to make the coal to be a clean energy for using is an important issue in the world, IGCC is an opportunity of clean coal using that couple with capture carbon dioxide technology (CCS) and other pollution controller unit to reduce pollution in the process. The products of IGCC are hydrogen and carbon monoxide (syngas) mainly. Syngas was employed to burn in gas turbine to generate the electrical power. The gasification process is an important process in IGCC, in that dominates the efficiency of clean coal technology. , There are several sub-reactions and phase reactions in coal gasification such as evaporation, pyrolysis, combustion, reforming and homogenous and heterogeneous reaction, respectively. Coal-water slurry and bio-char slurry were employed to investigate the gasification process by numerical methods in this study. SIMPLE methods and standards k-ε model were employed to solve problems of pressure-velocity and turbulence, respectively. To track droplet via phase change used the discrete phase model and the DO model was for radiation characteristics calculation in droplet. The carbon conversion efficiency and cold gas efficiency were the performance index of gasifier in this study. These results of study showed that the efficiencies of combustion in gasification were optimized when O/C ratio were between 0.5 to 0.8. Therefore, we investigated the pressure and droplet size effect in coal water slurry in O/C ratio of 0.8. The evaluated pressure in gasifier confined the combustion regime to increase the flame temperature and reduce the transport of heat and mass of slurry and oxidizer in pressure of 1 to 20 atm. In addition, the evaluated pressure effect affected the penetration length and droplet residence time that were parameters of gasifier. operating parameters of In the pressure 1bar, droplet 400 μm and concentration 55% have better gasification. By the above conditions, 5% -20% of the coffee grounds char are mixed into the slurry, made into a bio-slurry and analyzed. There results show that char is added to improve levels of volatile matter. Carbon conversion rate is better, but cold gas efficiency decreases.
Yang, Yao-Wei, e 楊曜維. "Experimental Study of the Gasification Characteristics of Bio-Char Slurry and Coal Water Slurry in Entrained Bed Gasfier". Thesis, 2013. http://ndltd.ncl.edu.tw/handle/yg38sd.
Testo completo國立虎尾科技大學
機械與機電工程研究所
101
The purpose of this paper is to design a nozzle suitable for coal water slurry entrained bed gasifier, in which the most suitable nozzle is found through characteristics measurement of atomized cold flow field of the nozzle and gasification of entrained bed gasifier. For measurement of atomized cold flow field, the optical measurement technique and image observation are used to explore characteristics of nozzle atomization, where particle image velocimetry (PIV) is mainly used to measure the atomized flow field and make related calculations. Malvern spray laser particle size analyzer is used for atomized particle size analysis. The particle size is measured 10cm, 15cm and 20cm respectively below the spray. The nozzle is an internally-mixing air atomizing one. The atomization characteristics are judged at different nozzle assemblies (single-hole and four-hole), liquid concentrations (10%-30%), spray cone angles, particle size analysis and mass distribution. This lab established a 10kg/gr coal-water slurry entrained bed gasifier in Nanzih District, Kaohsiung City. The reaction zone of the entrained bed is 1020mm long and 200m in diameter. The effects of different parameters on gasification results are explored at different nozzle assemblies, bio-coal slurry and O/C (mole/mole); the reaction is explored based on the temperature records of gasifier and output of main gaseous products (H2, CO, CO2); the measurement of atomization characteristics of cold flow field and the result of gasification are compared for verification. The experimental result shows that the single-hole air atomizing nozzle needs higher energy output when high flow working gas is operating. When the liquid-gas ratio is different, the operating range of the multihole nozzle is wider than that of the single-hole nozzle. However, these do not happen for the multihole nozzle. As for particle size analysis, the particle size of the atomized liquid drop of the single-hole nozzle is smaller than that of the atomized liquid drop of the multihole nozzle. With the increase of the impact gas flow, the atomized particle size reduces gradually; when it reaches a certain value, the changes of the atomized particle size become unobvious. In the experiment of the coal-water slurry entrained bed gasifier, the single-hole internally-mixing nozzle has higher reaction of combustion than the single-hole externally-mixing nozzle. This research will improve the nozzle in the future so as to improve gasification reaction efficiency and carbon conversion efficiency.
Yin-ChuChen e 陳映竹. "Numerical Analyses of an Entrained-Flow Coal Slurry Gasifier with Separate Oxygen-Feeding Streams". Thesis, 2014. http://ndltd.ncl.edu.tw/handle/55770534076970252779.
Testo completo國立成功大學
航空太空工程學系
102
The characteristic design of a Texaco gasifier, with a coaxial coal-slurry oxygen-jet nozzle and an outer annular oxygen-jet, has a significant influence on the gasification process. For the fuel-oxidant coaxial jet nozzle, the central oxygen-jet flow impinges on the coal-slurry stream and assists in the atomization of the coal slurry. The outer oxygen-jet, which splits the oxygen intake stream into two, makes an influence of the flame position and causes an effect of the gasification efficiency and coal conversion rate. In the study, numerical simulations of the coal slurry gasification process inside an entrained-flow gasifier with separate oxygen feeding streams are investigated using the commercial computational fluid dynamic software, ANSYS/ FLUENT. Three parameters, namely, positions of the outer annulus feeding tunnel, oxygen/carbon ratio, and oxygen feeding velocity of the outer annulus streams, have been examined to determine the effects of operating conditions on the gasification process. The numerical results show that the flame distribution is affected by the positions of the outer tunnel. As the outer tunnel is moved away from the central axis, the flame surface is extended and leads to a higher temperature in the downstream of the gasifier. In the investigations of the oxygen/carbon ratio, the lower the oxygen/carbon ratio is, the lower outlet temperature and the poorer the coal conversion rate. The distribution of the combustion region and the coal conversion rate is strongly affected by the feeding velocity of the outer annulus stream. The coal conversion rate and the cold gas efficiency are in a descending trend when the oxidant feeding is operated in high velocity. The compositions of the product gases are affected by the WGS. Moreover, the reaction rate of the WGS reaction is sensitive to the temperature of the gasification chamber.