流體化床反應爐具有高效率、高熱傳率、低燃燒溫度、低汙染物排放及燃料選擇限制較低等優點，已廣泛地被運用於化學工業及發電廠上。本研究以計算流體力學軟體FLUENT做為模擬之計算軟體，利用歐拉-歐拉方法針對流體化床之多相流建立分析模式，在歐拉模型中，氣-固兩相將被視為互相滲透的連續流體來處理。此模擬分析模式之物理模式包括：k-ε紊流模式、紊流反應模式、熱輻射模以及顆粒流分子運動論。研究中，先對三維流體化床冷流流場進行分析，研究氣泡之成因並確立流體化床速度之操作範圍。在煤炭氣化之研究部分，其結果之出口氣體組成與實驗進行比對，得到相似之趨勢，同時探討氣化過程中各反應之影響。在參數分析部分，則進行不同ER值對氣化之影響，結果發現ER值對於流體化床之沙床溫度影響不大，但會影響出口成份之組成，隨著ER值之升高，出口一氧化碳濃度將會增加，而氫氣之濃度則會隨ER值提升而降低。

Fluidized-bed reactors are widely used in many chemical industries and power plants, since they are characterized by the features of high efficiency, high heat transfer rates, low combustion temperature, low pollutant emissions, and less limitations on fuel selection. Combustion and gasification technology of pulverized coal in a fluidized-bed gasifier is thus an essential one for clean-coal technologies. In the present study, a numerical model for the simulation of combustion and gasification of pulverized coal in a bubbling fluidized-bed gasifier has been developed by using the commercial CFD software, ANSYS/ FLUENT. The Eulerian-Eulerian approach is employed for the gas-solid multiphase flow, where different phases are treated as interacting continua. The physical sub-models include the char oxidation model, the turbulent combustion model, and the thermal radiative model. The finite-rate and eddy-dissipation combustion models are employed for the gas combustion. A model-gasifier with a height of 200 cm and a diameter of 22 cm has been investigated by the present model. The bituminous coal, Colombia coal, is used as the feedstock in the study to verify with the reference data. For the parameter analyses, the Equivalence ratio(ER ratio) is conducted for evaluating the effect of coal gasification. The numerical results show that the outlet gas compositions predicted by the study are generally in agreement with the experiment data. In this model, CO2 is slightly underestimated and H2 is overestimated in the numerical model.

【1】International Energy Agency, "World Energy Outlook 2014", 2014.
【2】經濟部能源局, "能源統計手冊", 2013.
【3】周志成, "石油焦氣化技術研究", 國立成功大學航空太空工程研究所碩士論文,2002.
【4】Singh RI, Brink A, and Huppa M, "CFD Modeling to Study Fluidized Bed Combustion and Gasification", Applied Thermal Engineering, vol. 52, pp. 585-614, 2013.
【5】https://scitechvista.most.gov.tw/zh-tw/articles/c/0/12/10/1/1420.htm
【6】(BEE) Government of India, "Energy Efficiency in Thermal Utilities", 2005.
【7】Anthony DB and Howard JB, "Coal Devolatilization and Hydrogasification", American Institute of Chemical Engineers, vol. 22, pp. 625-656, 1976.
【8】Agarwal PK, "A Single Particle Model for the Evolution and Combustion of Coal Volatiles", Fuel, Vol. 65, pp.803-810, 1986.
【9】Smoot LD, "Coal Gasification, Encyclopedia of Energy Technology and the Environment", Vol. 4, pp. 769-792, 1995.
【10】Smith IW and Review TCRoCCA, "The Combustion Rates of Coal Chars: A Review", The Combustion Institute, vol. 19, pp. 1045-1065, 1982.
【11】Tolvanen HM, Kokko LI, and Raiko R, "The Factors Controlling Combustion and Gasification Kinetics of Solid Fuels", The Swedish and Finnish National Committees of the International Flame Research Foundation, 2011.
【12】Ducarne ED, Dolignie JC, and Marty E, "Modelling of Gaseous Pollutants Emissions in Circulating Fluidized Bed Combustion of Municipal Refuse", Fuel, vol. 77, pp. 1399-1410, 1998.
【13】Wang T and Silaen A, "Effects of Turbulence and Devolatilization Models on Gasification Simulation", International Pittsburgh Coal Conference, Pittsburgh, 2008.
【14】Rehm M, Seifert P, and Meyer B, "Theoretical and Numerical Investigation on the EDC-Model for Turbulence–Chemistry Interaction at Gasification Conditions", Computers and Chemical Engineering, vol. 33, pp. 402-407, 2009.
【15】Wang T and Silaen A, "Comparison of Instantaneous, Equilibrium, and Finite-Rate Gasification Models in an Entrained-Flow Coal Gasifier", International Pittsburgh Coal Conference, Pittsburgh, 2009.
【16】Smoot LD and Brown BW, "Controlling Mechanisms in Gasification of Pulverized Coal", Fuel, vol. 66, pp. 1249-1256, 1987.
【17】Wall TF, Liu GS, Wu HW, Roberts DG, Benfell KE, Gupta S, et al, "The Effects of Pressure on Coal Reactions During Pulverised Coal Combustion and Gasification", Progress in Energy and Combustion Science, vol. 28, pp. 405-433, 2002.
【18】Agarwal PK, "A Single Particle Model for the Evolution and Combustion of Coal Volatiles", Fuel, vol. 65, pp. 803-810, 1986.
【19】Ajilkumar A, Sundararajan T, and Shet USP, "Numerical Modeling of a Steam-Assisted Tubular Coal Gasifier", International Journal of Thermal Sciences, vol. 48, pp. 308-321, 2009.
【20】周可仲, "含觸媒焦炭在氣固流體化床氣化反應的實驗探討", 大同大學化學工程研究所 碩士論文, 2001.
【21】Watanabe H and Otaka M, "Numerical Simulation of Coal Gasification in Entrained Flow Coal Gasifier", Fuel, vol. 85, pp. 1935-1943, 2006.
【22】Gómez-Barea A and Leckner B, "Modeling of Biomass Gasification in Fluidized Bed", Progress in Energy and Combustion Science, vol. 36, pp. 444-509, 2010.
【23】Gräbner M, Ogriseck S, and Meyer B, "Numerical Simulation of Coal Gasification at Circulating Fluidized Bed Conditions", Fuel Processing Technology, vol. 88, pp. 948-958, 2007.
【24】Wang Y and Yan L, "CFD Modeling of a Fluidized Bed Sewage Sludge Gasifier for Syngas", Asia-Pacific Journal of Chemical Engineering, vol. 3, pp. 161-170, 2008.
【25】Armstrong LM, Gu S, Luo KH, "CFD Modelling of the Co-Gasification of Biomass and Coal Particles in Fluidized Beds", Proceedings of the Bioten Conference on Biomass Bioenergy and Biofuels 2010, CRC Press, Birmingham,GB, 2010.
【26】Gerber S, Behrendt F, Overmann M, "An Eulerian Modeling Approach of Wood Gasification in a Bubbling Fluidized Bed Reactor Using Char as Bed Material", Fuel, pp.2903-2917, 2010.
【27】Gerber S, Behrendt F, Oevermann M, "Comparative Study of Euler-Euler and Euler-Lagrange Modelling of Wood Gasification in a Dense Fluidized bed", Proceeding of the 20th International Conference on FBC, pp. 693-699, 2009.
【28】Deng Z, Xiao R, Jin B, Huang H, Shen L, Song Q, Qianjun L, "Computational Fluid Dynamics Modeling of Coal Gasification in a Pressurized Spout-Fluid Bed", Energy and Fuels , vol.22, pp. 1560-1569, 2008.
【29】Yu L, Lu J, Zhang X, Zhang S, "Numerical Simulation of the Bubbling Fluidized Bed Coal Gasification by the Kinetic Theory of Granular Flow (KTGF) ", Fuel, vol.86, pp.772-734, 2007.
【30】Cornejo P, Farıas O, "Mathematical Modeling of Coal Gasification in a Fluidized Bed Reactor Using a Eulerian Granular Description", International Journal of Chemical Reactor Engineering, vol.9, pp.1-3, 2011.

【31】Armstrong LM, Gu S., Luo KH, "Parametric Study of Gasification Processes in a BFB Coal Gasifier", Industrial and Engineering Chemistry Research, vol.50, pp. 5959-5974, 2011.
【32】Zhou M, Yan LF, Guo QX, Zhu QS, "Non Premixed Combustion Model of Fluidized Bed Biomass Gasifier for Hydrogen Rich Gas", Chinese Journal of Chemical Physics, vol.19, pp.131-136, 2006.
【33】Wang Y, Yan L, "CFD Based Combustion Model for Sewage Sludge Gasification in a Fluidized Bed", Frontiers of Chemical Engineering in China, vol.3, pp.138-145, 2009.
【34】He L, Schotte E, Thomas S, Schlinkert A, Herrmann A, Mosch V, Rajendran V, Heinrich S, "Wood Gasification in a Lab-Scale Bubbling Fluidized Bed: Experiment and Simulation", Proceeding of 20th International Conference on fluidized bed combustion, pp.686-692, 2010.
【35】Ocampo A, Arenasb E, Chejnea F, Espinela J, London C, Aguirrea J, et al., "An Experimental Study on Gasification of Colombian Coal in Fluidized Bed", Fuel, Vol. 82, pp. 161-164, 2003.
【36】Wang X, Jin B, and Zhong W, "Three-Dimensional Simulation of Fluidized Bed Coal Gasification", Chemical Engineering and Processing, vol. 48, pp. 695-705, 2009.
【37】 Chejne F, Hernandez JP, "Modeling and Simulation of Coal Gasification Process in Fluidized Bed", Fuel, vol.81, pp.1687–702, 2002.
【38】ANSYS, ANSYS FLUENT 14.0 Theory Guide, ANSYS, Inc., Southpointe, 2011.
【39】Lun C, Savage S, Jeffrey D, Chepurniy N, "Kinetic Theories for Granular Flow:Inelastic Particles in Couette Flow and Slightly Inelastic Particles in a General Flow Field," Journal of Fluid Mechanics, Vol. 140, pp. 223-256, 1984.
【40】Gidaspow D, Multiphase Flow and Fluidization: Continuum and Kinetic Theory Descriptions, Academic Press, London, 1994.
【41】 Enwald H, Peirano E, Almstedt AE, Leckner B, "Simulation of the Fluid Dynamics of a Bubbling Fluidized Bed Experimental Validation of the Two-Fluid Model and Evaluation of a Parallel Multiblock Solver", Chem Eng Sci , vol.54, pp.311-328, 1999.
【42】Launder BE, Spalding DB, Lectures in Mathematical Models of Turbulence, Academic Press, London, England, 1972.
【43】Cheng P, "Two-Dimensional Radiating Gas Flow by a Moment Method", American Institute of Aeronautics and Astronautics, vol. 2, pp. 1662-1664, 1964.
【44】Weimer AW and Clough DE, "Modeling a Low Pressure Steam-Oxygen Fluidized Bed Coal Gasifying Reactor", Chemical Engineering Science, vol.36, pp.549–567, 1981.
【45】Klimanek A, "Towards a Hybrid Eulerian–Lagrangian CFD Modeling of Coal Gasification in a Circulating Fluidized Bed Reactor", Fuel, vol.152, pp.131–137,2015.
【46】Vasconcelo S, "Minimum and Full Fluidization Velocity for Alumina Used in the Aluminum Smelter", International Journal of Engineering Business Management, vol.3, no 4, pp.7-13, 2011.
【47】Basu P, Combustion and Gasification in Fluidized Beds, CRC Press, 2006
【48】Bi HT and Grace JR., "Flow Regime Diagrams for Gas-Solid Fluidization and Upward Transport", Int. J. Muhiphase Flow, vol.21, pp.1229-1236, 1995.