跳到主要內容

簡易檢索 / 詳目顯示

研究生: 丁公平
Dinh Cong Binh
論文名稱: 雙流化床氣化冷流系統之計算流體力學 (CFD) 研究與實驗驗證
Computational fluid dynamics (CFD) study with experimental validation of a dual fluidized bed gasification cold flow system
指導教授: 蕭述三
Hsiau Shu-San
口試委員:
學位類別: 博士
Doctor
系所名稱: 工學院 - 能源工程研究所
Graduate Institute of Energy Engineering
論文出版年: 2019
畢業學年度: 108
語文別: 英文
論文頁數: 107
中文關鍵詞: 雙流化床冷流系統不穩定的特徵多相流模型砂循環率意外的逆流
外文關鍵詞: dual fluidized bed, cold flow system, unsteady characteristics, multiphase flow model, sand circulation rates, unexpected reverse flow
相關次數: 點閱:12下載:0
分享至:
查詢本校圖書館目錄 查詢臺灣博碩士論文知識加值系統 勘誤回報
  • 產學界提出雙流化床系統技術,並已成功地應用於生物質氣化以產生高質量的產物合成氣。我們在台灣NCU的實驗室中設計並安裝了一個雙流化床氣化(DFBG)冷流系統,該系統以氣動空氣作為流化媒介,並以矽砂作為床層材料。以實驗和數值研究該系統中空氣-矽砂流動的非穩態特性。除了以商業軟件ANSYS FLUENT開發二維計算流體動力學(CFD)模型外,還使用與CFD模型相同的工作條件同時進行了實驗測試,以研究影響系統流體動力學的參數。將歐拉多相流模型與顆粒流動力學理論相結合,在整個過程中執行了空氣和砂相的非穩態行為。在這項研究工作中,初始時觀察並分析了不同操作和幾何條件下流體流動行為的變化。後續接著對主要因素進行參數研究,例如流化空氣入口速度和靜態砂床高度,以確定它們對流體流動特性的影響。對於DFBG系統不同區域的固體流型,壓力分佈,壓降和砂的循環速率,獲得了一些典型結果。
    砂的體積分率的結果分別正確地確認了在氣化爐和立管中形成的鼓泡和快速流化模式。立管進氣速度和靜態砂床高度發現會顯著影響砂體積分率,混合物壓力和砂循環速率的分佈,而氣化爐進氣速度對這些分佈曲線的影響卻很小。底部區域的混合物壓力大於上部區域的混合物壓力,從而保持了氣體密封、固體分離和固體循環的穩定運行。同時顯示出總砂流量隨立管空氣速度的增加而顯著增加,而不隨著氣化爐中流化空氣速度和立管靜態床層高度的變化明顯變化。還值得注意的是,初始沙床高度和立管中空氣入口速度的進一步增加應被限制在其最大值,否則,可能會發生意外的逆流,從而中斷壓力平衡和系統的正常運行。通常,應適當控制所有影響參數,以確保系統穩定運行。儘管建模結果相對再現了實驗數據,但是由於所提出的是簡化模型,它們之間仍然存在某些差異。所有獲得的結果可期望為防止不良現像以及改善實際DFBG工廠的設計和性能提供可靠實用的預測。


    The technology of dual fluidized bed system has been proposed and successfully applied to biomass gasification to generate product syngas of high quality. A dual fluidized bed gasification (DFBG) cold flow system, equipped with pneumatic air as a fluidizing agent and silica sand as bed material, has been designed and installed at our lab in NCU, Taiwan. The unsteady characteristics of the air-silica sand flow in that system have been studied experimentally and numerically. Besides developing a two-dimensional computational fluid dynamics (CFD) model with the commercial software ANSYS FLUENT, experimental tests were simultaneously conducted with the same operating conditions as those of the CFD model to investigate the parameters affecting the system hydrodynamics. A combination of the Eulerian multiphase flow model and the kinetic theory of granular flows was applied to perform the unsteady behaviors of the air and sand phases during the entire process. The variations of the fluid flow behavior with different operating and geometrical conditions were initially observed and analyzed in this work. Accordingly, a parametric study was carried out for the major factors, such as fluidizing air inlet velocities and static sand bed heights, to determine their effects on the fluid flow characteristics. Some typical results were obtained for the solid flow patterns, pressure distribution, pressure drop, and sand circulation rate in different zones and over the height of the DFBG system.
    The results of the sand volume fraction properly identified the bubbling and fast fluidization patterns formed in the gasifier and riser, respectively. The riser air inlet velocity and static sand bed height were found to considerably affect the distributions of sand volume fraction, mixture pressure and sand circulation rates, while the gasifier air inlet velocity insignificantly influenced to those profiles. The mixture pressures at the bottom regions were greater than those at the upper regions, which maintain the stable operations of gas sealing, solid separation, and solid circulation. It was also indicated that the total sand flow rates considerably increased with the increasing riser air velocity, while they did not significantly change with varying the fluidizing air velocity in the gasifier and the riser static bed height. It was also noteworthy that further increases of the initial sand bed height and the air inlet velocity in the riser were restricted at their maximum values, otherwise, an unexpected reverse flow possibly occurred to interrupt the pressure balance and normal operation of the system. In general, all affecting parameters should be appropriately controlled to ensure stable system operation. Although the modeling results relatively reproduced the experimental data, there still existed certain discrepancies between them due to the simplifications of the proposed model. All the obtained results are expected to provide valuable predictions for preventing undesired phenomena and for improving the designs and performances of practical DFBG plants.

    摘要 i Abstract ii Acknowledgments iv Table of Contents v List of Figures viii List of Tables xi Nomenclature with Units xii Abbreviations xv Chapter 1: Introduction 1 1.1. Research motivation 1 1.2. Research objectives 3 1.3. Dissertation structure 4 Chapter 2: Theoretical background and Literature review 5 2.1. Fundamentals of fluidization and fluidized bed technology 5 2.1.1. Geldart classification of solid particles 5 2.1.2. Minimum fluidization velocity of the solid phase 7 2.1.3. Terminal velocity of the solid phase 8 2.1.4. Superficial gas velocity 9 2.1.5. Regimes of fluidization 9 2.2. Non-mechanical valves and loop-seals in CFB systems 11 2.3. Operation principle of a DFBG system 12 2.4. Overview of the feedstock used in a DFBG system 13 2.4.1. Biomass as a fuel 14 2.4.2. Bed materials 14 2.5. Hydrodynamic parameters commonly considered in a cold flow DFBG system 16 2.6. Potential of the CFD in modeling DFB systems 17 2.7. Literature review 18 Chapter 3: Methodology 21 3.1. Experimental DFBG CFM 21 3.1.1. Design and description of the experimental CFM 21 3.1.2. Measurement techniques and data acquisition 22 3.1.3. Experimental parameters with related calculations 24 3.2. CFD model development 25 3.2.1. Introduction of the commercial CFD software ANSYS FLUENT version 17.2 25 3.2.2. Geometry and meshing 27 3.2.3. Multiphase flow model – Governing equations 30 3.2.3.1. Conservation equations 30 a. Continuity equations for the phases (conservation of mass) 30 b. Momentum equations for the phases (conservation of momentum) 30 3.2.3.2. Closure equations 30 a. Drag model – Interphase momentum transfer 31 b. Stress tensor 32 c. Solid-phase pressure 32 d. Solid shear viscosity 32 e. Solid bulk viscosity 32 f. Radial distribution function 33 g. The KTGF for the secondary sand phases 33 3.2.3.3. Turbulence model for the primary air phase and secondary sand phases 34 3.2.4. Simulation setup and boundary conditions 35 3.2.5. 3D CFD modeling of the air-sand flow behaviors in the cyclone of the DFBG system 37 Chapter 4: Results and discussion 39 4.1. Some typical CFD results 39 4.1.1. Mesh-independent analysis 39 4.1.2. Sand flow characteristics – Distribution of sand volume fraction 40 4.1.3. Pressure drop 45 4.1.4. Mixture pressure distribution 47 4.1.5. Sand circulation rates 51 4.1.6. Sands mass balances 54 4.2. Validation of the CFD predicted results with experimental data 55 4.2.1. Flow patterns of the operating experimental system 56 4.2.2. Profiles of mixture static pressure 57 4.2.3. Sand circulation rates 61 4.2.4. Air-sand flow behaviors in the cyclone of the DFBG system 64 Chapter 5: Conclusions and Recommendations 66 5.1. Conclusions 66 5.2. Recommendations 67 Bibliographies 69 Appendices 79 Appendix A: Calculations 79 A.1. Modeling parametric study 79 A.1.1. Calculation of the minimum fluidization velocity 79 A.1.2. Simulation cases 79 A.2. Theoretical formulations 80 A.2.1. Calculation of turbulent intensity – Boundary conditions used in the CFD model 80 A.2.2. Calculation of sand circulation rates 81 A.2.3. Evaluation of the fluctuation and stability of sand circulation 82 Appendix B: Supplemental data 83 Appendix C: Some related photos 84 Appendix D: Publications 88

    Almuttahar, A., Taghipour, F., 2008. Computational fluid dynamics of a circulating fluidized bed under various fluidization conditions. Chem. Eng. Sci. 63 (6), 1696-1709. doi:10.1016/j.ces.2007.11.020.
    ANSYS Inc., 2016. ANSYS FLUENT User's Guide and Theory Guide, Version 17.2.
    Azadi, M., Azadi, M., Mohebbi, A., 2010. A CFD study of the effect of cyclone size on its performance parameters. J. Hazard. Mater. 182(1-3), 835-841. doi: 10.1016/j.jhazmat.2010.06.115.
    Basu, P., 2006. Combustion and Gasification in Fluidized Beds, Taylor and Francis, USA.
    Benyahia, S., Arastoopour, H., Knowlton, T.M., Massah, H., 2000. Simulation of particles and gas flow behavior in the riser section of a circulating fluidized bed using the kinetic theory approach for the particulate phase. Powder Technol. 112 (1-2), 24-33. doi: 10.1016/S0032-5910(99)00302-2.
    Bergman, T.L., Lavine, A.S., Incropera, F.P., DeWitt, D.P., 2011. Appendix A: Thermophysical Properties of Matters, in: Bergman, T.L., Lavine, A.S., Incropera, F.P., DeWitt, D.P. (Eds.), Fundamentals of Heat and Mass Transfer, seventh ed. John Wiley & Sons Inc., New Jersey, USA, pp. 983-1011.
    Bhaskaran, S., Gupta, S., De, S., 2018. Dual Fluidized Bed Gasification of Solid Fuels, in: De, S., Agarwal, A., Moholkar, V., Thallada, B. (Eds.), Coal and Biomass Gasification. Energy, Environment, and Sustainability. Springer, Singapore, pp. 425-454.
    Bidwe, A.R., 2017. Hydrodynamic studies of the dual fluidized bed reactor systems for high temperature solid looping cycles. Ph.D. Thesis, University of Stuttgart, Germany.
    Bidwe, A.R., Hawthorne, C., Xizhi, Y., Dieter, H., Scheffknecht, G., 2014. Cold model study of a dual fluidized bed system for the gasification of solid fuels. Fuel 127, 151-160. doi: 10.1016/j.fuel.2013.12.020.
    Bull, D. R., 2008. Performance Improvements to a Fast Internally Circulating Fluidized Bed (FICFB) Biomass Gasifier for Combined Heat and Power Plants. M.Sc. Thesis, University of Canterbury, New Zealand.
    Charitos, A., Hawthorne, C., Bidwe, A. R., Korovesis, L., Schuster, A., & Scheffknecht, G., 2010. Hydrodynamic analysis of a 10kwth calcium looping dual fluidized bed for post-combustion CO2 capture. Powder Technol., 200(3), 117-127. doi: 10.1016/j.powtec.2010.02.012.
    Chen, Y., Adams, T.A., Barton, B.I., 2011. Optimal design and operation of static energy polygeneration systems. Ind. Eng. Chem. Res. 50 (9), 5099-5113. doi: 10.1021/ie101568v.
    Chen, Y.G., Tian, Z.P., Miao, Z.Q., 2006. Analysis of the pressure fluctuations in binary solids circulating fluidized bed. Energy Convers. Manage. 47 (5), 611-623. doi: 10.1016/j.enconman.2005.05.013.
    Chen, W., Williams, K.C., Jones, M.G., 2016. Applications of Numerical Modeling in Pneumatic Conveying, in: Mills, D. (Ed.), Pneumatic Conveying Design Guide, third ed. Butterworth-Heinemann, Oxford, UK, pp. 521-552.
    Cheng, L., Basu, P., 1999. Effect of pressure on loop seal operation for a pressurized circulating fluidized bed. Powder Technol. 103 (3), 203-211. doi: 10.1016/S0032-5910(99)00018-2.
    Chitester, D.C., Kornosky, R.M., Fan, L.S., Danko, J.P., 1984. Characteristics of fluidization at high pressure. Chem. Eng. Sci. 39 (2), 253-261. doi: 10.1016/0009-2509(84)80025-1.
    Chu, K.W., Wang, B., Xu, D.L., Chen, Y.X., Yu, A.B., 2011. CFD-DEM simulation of the gas-solid flow in a cyclone separator. Chem. Eng. Sci. 66, 834-847. doi: 10.1016/j.ces.2010.11.026.
    Corella, J., Toledo, J.M., Molina, G., 2007. A review on dual fluidized bed biomass gasifiers. Ind. Eng. Chem. Res. 46, 6831-6839. doi: 10.1021/ie0705507.
    Cortés, C., Gil, A., 2007. Modeling the gas and particle flow inside cyclone separators. Prog. Energy Combust. Sci. 33, 409-452. doi: 10.1016/j.pecs.2007.02.001.
    Cui, J., Chen, X., Gong, X., Yu, G., 2010. Numerical study of gas-solid flow in a radial-inlet structure cyclone separator. Ind. Eng. Chem. Res. 49 (11), 5450-5460. doi: 10.1021/ie901962r.
    Derksen, J.J., 2003. Separation performance predictions of a stairmand high-efficiency cyclone. AIChE J. 49 (6), 1359-1371. doi: 10.1002/aic.690490603.
    Ding, J., Gidaspow, D., 1990. A bubbling fluidization model using kinetic theory of granular flow. AIChE J. 36 (4), 523-538. doi: 10.1002/aic.690360404.
    Dinh, C.B., Liao, C.C., Hsiau, S.S., 2017. Numerical study of hydrodynamics with surface heat transfer in a bubbling fluidized-bed reactor applied to fast pyrolysis of rice husk. Adv. Powder Technol. 28 (2), 419-429. doi: 10.1016/j.apt.2016.10.013.
    Dinh, C.B., Hsiau, S.S., Su, C.Y., Tsai, M.Y., Chen, Y.S., Nguyen, H.B., Wan, H.P., 2019. Predictions of undesirable air-sand flow behaviors in a dual fluidized bed cold flow system via a CFD full-loop model, Journal of the Taiwan Institute of Chemical Engineers. In Press.
    Elsayed, K., 2011. Analysis and Optimization of Cyclone Separators Geometry Using RANS and LES Methodologies. Ph.D. Thesis, Vrije Universiteit Brussel, Belgium.
    Elsayed, K., Lacor, C., 2011. The effect of cyclone inlet dimensions on the flow pattern and performance. Appl. Math. Modell. 35 (4), 1952-1968. doi: 10.1016/j.apm.2010.11.007.
    Ergun, S., 1952, Fluid flow through packed columns. Chem. Eng. Prog. 48 (2), 89-94.
    Folkeson, B., 2014. Propensity of bed materials used in dual fluidized beds to retain ash-forming elements from biomass fuels. M.Sc. Thesis, Swedish University of Agricultural Sciences, Sweden.
    Geldart, D., Jones, P., 1991. The behaviour of l-valves with granular powders. Powder Technol. 67 (2), 163-174. doi: 10.1016/0032-5910(91)80153-A.
    Geng, C.M., Zhong, W.Q., Shao, Y.J., Chen, D.L., Jin, B.S., 2015. Computational study of solid circulation in chemical-looping combustion reactor model. Powder Technol. 276, 144-155. doi: 10.1016/j.powtec.2015.01.077
    Gibilaro, L.G., 2001. Fluidization Dynamics, Butterworth-Heinemann, UK.
    Gidaspow, D., 1994. Multiphase Flow and Fluidization: Continuum and Kinetic Theory Descriptions, Academic Press, Boston.
    Gidaspow, D., Bezburuah, R., Ding, J., 1992. Hydrodynamics of Circulating Fluidized Beds, Kinetic Theory Approach, in: Potter, O.E., Nicklin, D.J. (Eds.), Fluidization VII: Proceedings of the 7th Engineering Foundation Conference on Fluidization, Engineering Foundation, New York, pp. 75-82.
    Goo, J.H., Seo, M.W., Park, D.K., Kim, S.D., Lee, S.H., Lee, J.G., Song, B.H., 2008. Hydrodynamic properties in a cold-model dual fluidized-bed gasifier. J. Chem. Eng. Jpn. 41 (7), 686-690. doi: 10.1252/jcej.07WE111.
    Grace, J.R., Bi, H., 1997. Introduction to Circulating Fluidized Beds, in: Grace, J.R., Avidan, A.A., Knowlton, T.M. (Eds) Circulating Fluidized Beds. Springer, Dordrecht. doi: 10.1007/978-94-009-0095-0_1.
    Grieco, E., Marmo, L., 2006. Predicting the pressure drop across the solids flow rate control device of a circulating fluidized bed. Powder Technol. 161 (2), 89-97. doi: 10.1016/j.powtec.2005.08.035.
    Guan, Y.J., Chang, J., Zhang, K., Wang, B.D., Sun, Q., 2014. Three-dimensional CFD simulation of hydrodynamics in an interconnected fluidized bed for chemical looping combustion. Powder Technol. 268, 316-328. doi: 10.1016/j.powtec.2014.08.046.
    Guan, Y.J., Chang, J., Zhang, K., Wang, B.D., Sun, Q., Wen, D.S., 2016. Three-dimensional full loop simulation of solids circulation in an interconnected fluidized bed. Powder Technol. 289, 118-125. doi: 10.1016/j.powtec.2015.11.043.
    Habl, M.A., Frohner, A., Tondl, G., Pfeifer, C., 2017. Fluid dynamics study on a dual fluidized bed cold-flow model. Powder Technol. 316, 469-475. doi: 10.1016/j.powtec.2016.12.064.
    Hejazi, B., Grace, J.R., Bi, X.T., Andres, M.B., 2017. Kinetic Model of Steam Gasification of Biomass in a Dual Fluidized Bed Reactor-Comparison with Pilot-Plant Experimental Results. Energy Fuels 31, 12141-12155. doi: 10.1021/acs.energyfuels.7b01833.
    Hofbauer, H., 2006. Scale Up of Fluidized Bed Gasifiers from Laboratory Scale to Commercial Plants: Steam Gasification of Solid Biomass in a Dual Fluidized Bed System, in: Winter, F. (Ed.), 19th Int. Conf. Fluid. Bed Combust., Vienna, Austria.
    Hofbauer, H., Rauch, R., Bosch, K., Koch, R., Aichernig, C., 2003. Biomass CHP Plant Gussing – A Success Story, in: Bridgwater, A.V. (Ed.), Pyrolysis and gasification of biomass and waste, CPL Press, Newbury, UK, pp. 527-536.
    Hofbauer, H., Rauch, R., Loeffler, G., Kaiser, S., Fercher, E., Tremmel, H., 2002. Six years experience with the FICFB-gasification process. 12th European Conference and Technology Exhibition on Biomass for Energy, Industry and Climate Protection, Amsterdam.
    Hoffmann, A., Stein, L., 2008. Gas Cyclones and Swirl Tubes: Principles, Design and Operation. second ed., Springer-Verlag Berlin Heidelberg, New York.
    Huilin, L., Gidaspow, D., 2003. Hydrodynamics of binary fluidization in a riser: CFD simulation using two granular temperatures. Chem. Eng. Sci. 58, 3777-3792. doi: 10.1016/S0009-2509(03)00238-0.
    Jang, H.T., Park, T.S., Cha, W.S., 2010. Mixing-segregation phenomena of binary system in a fluidized bed. J. Ind. Eng. Chem. 16 (3), 390-394. doi: 10.1016/j.jiec.2009.10.003.
    Jiao, J., Liu, Z., Zheng, Y., 2007. Evaluations and modifications on reynolds stress model in cyclone simulations. Chem. Eng. Technol. 30 (1), 15-20. doi: 10.1002/ceat.200600311.
    Johnson, P.C., Jackson, R., 1987. Frictional-collisional constitutive relations for granular materials, with application to plane shearing. J. Fluid Mech. 176, 67-93. doi: 10.1017/S0022112087000570.
    Kaiser, S., Löffler, G., Bosch, K., Hofbauer, H., 2003. Hydrodynamics of a dual fluidized bed gasifier, Part II: simulation of solid circulation rate, pressure loop and stability. Chem. Eng. Sci. 58 (18), 4215-4223. doi: 10.1016/S0009-2509(03)00233-1.
    Karagoz, I., Kaya, F., 2007. CFD investigation of the flow and heat transfer characteristics in a tangential inlet cyclone. Int. Commun. Heat Mass Transfer 34 (9-10), 1119-1126. doi: 10.1016/j.icheatmasstransfer.2007.05.017.
    Karmakar, M.K., Datta, A.B., 2010. Hydrodynamics of a dual fluidized bed gasifier. Adv. Powder Technol. 21, 521-528. doi: 10.1016/j.apt.2010.02.001.
    Kraft, S., Kirnbauer, F., Hofbauer, H., 2017. Investigations using a cold flow model of char mixing in the gasification reactor of a dual fluidized bed gasification plant. Powder Technol. 316, 687-696. doi: 10.1016/j.powtec.2016.10.032.
    Kunii, D., Levenspiel, O., 1991. Fluidization Engineering, second ed. Butterworth-Heinemann, London.
    Kunii, D., Levenspiel, O., 1997. Circulating fluidized-bed reactors. Chem. Eng. Sci. 52(15), 2471–2482. doi: 10.1016/S0009-2509(97)00066-3.
    Latif, A., 1999. A study of the design of fluidized bed reactors for biomass gasification. Ph.D. Thesis, University of London, UK.
    Li, T., Dietiker, J., Shahnam, M., 2012. MFIX simulation of NETL/PSRI challenge problem of circulating fluidized bed. Chem. Eng. Sci. 84, 746-760. doi: 10.1016/j.ces.2012.09.024.
    Li, T., Pannala, S., Shahnam, M., 2014. CFD simulations of circulating fluidized bed risers, part II, evaluation of differences between 2D and 3D simulations. Powder Technol. 254, 115-124. doi: 10.1016/j.powtec.2014.01.022.
    Lim, M.T., 2012. Hydrodynamics of a Cold Model of a Dual Fluidized Bed Gasification Plant. Ph.D. Thesis, University of Canterbury, Christchurch, New Zealand.
    Lim, M.T., Saw, W., Pang, S., 2015. Effect of fluidizing velocity on gas bypass and solid fraction in a dual fluidized bed gasifier and a cold model. Particuology 18, 58-65. doi: 10.1016/j.partic.2014.05.007.
    Liu, H., Cattolica, R.J., Seiser, R., 2016. CFD studies on biomass gasification in a pilot-scale dual fluidized-bed system. Int. J. Hydrogen Energy 41, 11974-11989. doi: 10.1016/j.ijhydene.2016.04.205.
    Liu, H., Cattolica, R.J., Seiser, R., 2017. Operating parameter effects on the solids circulation rate in the CFD simulation of a dual fluidized-bed gasification system. Chem. Eng. Sci. 169, 235-245. doi: 10.1016/j.ces.2016.11.040.
    Lun, C.K.K., Savage, S.B., Jeffrey, D.J., Chepurniy, N., 1984. Kinetic Theories for Granular Flow: Inelastic Particles in Couette Flow and Slightly Inelastic Particles in a General Flow Field. J. Fluid Mech. 140, 223-256. doi: 10.1017/S0022112084000586.
    Manchasing, C., Kuchonthara, P., Chalermsinsuwan, B., Piumsomboon, P., 2013. Experiment and computational fluid dynamics simulation of in-depth system hydrodynamics in dual-bed gasifier. Int. J. Hydrogen Energy 38 (25), 10417-10430. doi: 10.1016/j.ijhydene.2013.06.033.
    Marinkovic, J., 2016. Choice of bed material: a critical parameter in the optimization of dual fluidized bed systems. Ph.D. Thesis, Chalmers University of Technology, Sweden.
    Mauerhofer, A.M., Benedikt, F., Schmid, J.C., Hofbauer, H., 2017. Mixtures of Silica Sand and Calcite as Bed Material for Dual Fluidized Bed Steam Gasification, Proceedings of the 10th International Conference on Sustainable Energy and Environmental Protection – Bioenergy and Biofuels, Bled, Slovenia. doi: 10.18690/978-961-286-048-6.26.
    Mineto, A.T., Braun, M.P.D.S., Navarro, H.A., Gómez, L.C., 2014. Influence of the granular temperature in the numerical simulation of gas-solid flow in a bubbling fluidized bed. Chem. Eng. Commun. 201 (8), 1003-1020. doi: 10.1080/00986445.2013.794138.
    Nguyen, T.D.B., Seo, M.W., Lim, Y.I., Song, B.H., Kim, S.D., 2012. CFD simulation with experiments in a dual circulating fluidized bed gasifier. Comput. Chem. Eng. 36, 48-56. doi: 10.1016/j.compchemeng.2011.07.005.
    Pfeifer, C., Koppatz, S., Hofbauer, H., 2011. Steam gasification of various feedstocks at a dual fluidised bed gasifier: Impacts of operation conditions and bed materials. Biomass Convers. Biorefin. 1(1), 39-53. doi: 10.1007/s13399-011-0007-1.
    Rahman, M.H., Bi, X.T., Grace, J.R., Lim, C.J., 2017. Measurement of solids circulation rate in a high-temperature dual fluidized bed pilot plant. Powder Technol. 316, 658-669. doi: 10.1016/j.powtec.2017.01.073.
    Sahoo, P., Sahoo, A., 2014. A comparative study on effect of different parameters of CFD modeling for gas-solid fluidized bed. Part. Sci. Technol. 33 (3), 273-289. doi: 10.1080/02726351.2014.952393.
    Schmid, J., Pröll, T., Pfeifer, C., Hofbauer, H., 2011. Improvement of gas-solid interaction in dual circulating fluidized bed systems, in: Proceedings of the 9th European Conference on Industrial Furnaces and Boilers (INFUB) in Portugal, CENERTEC, Rio Tinto.
    Seo, M.W., Nguyen, T.D.B., Lim, Y.I., Kim, S.D., Park, S.W., Song, B.H., Kim, Y.J., 2011. Solid circulation and loop-seal characteristics of a dual circulating fluidized bed: Experiments and CFD simulation. Chem. Eng. J. 168 (2), 803-811. doi: 10.1016/j.cej.2011.01.041.
    Shah, S., Ritvanen, J., Hyppanen, T., Kallio, S., 2012. Space averaging on a gas-solid drag model for numerical simulations of a CFB riser. Powder Technol. 218, 131-139. doi: 10.1016/j.powtec.2011.11.053.
    Shih, T.H., Liou, W.W., Shabbir, A., Yang, Z.G., Zhu, J., 1995. A new k-epsilon eddy-viscosity model for high Reynolds number turbulent flows: Model development and validation. Comput. Fluids 24 (3), 227-238. doi: 10.1016/0045-7930(94)00032-T.
    Shrestha, S., Ali, B.S., Jan, B.M., Hamid, M.D.B., Sheikh, K.E., 2015. Hydrodynamic characteristics in cold model of dual fluidized bed gasifiers. Powder Technol. 286, 246-256. doi: 10.1016/j.powtec.2015.04.082.
    Shrestha, S., Ali, B.S., Jan, B.M., Lim, M.T., Sheik, K.E., 2016a. Hydrodynamic properties of a cold model of dual fluidized bed gasifier – A modeling and experimental investigation. Chem. Eng. Res. Des. 109, 791-805. doi: 10.1016/j.cherd.2016.04.002.
    Shrestha, S., Ali, B.S., Hamid, M.D.B., 2016b. Cold flow model of dual fluidized bed: A review. Renewable and Sustainable Energy Rev. 53, 1529-1548. doi: 10.1016/j.rser.2015.09.034.
    Shukla, S.K., Shukla, P., Ghosh, P., 2013. The effect of modeling of velocity fluctuations on prediction of collection efficiency of cyclone separators. Appl. Math. Modell. 37, 5774-5789. doi: 10.1016/j.apm.2012.11.019.
    Stendal, E.A.R., 2013. Multiphase Flows in Cyclone Separators-Modeling the classification and drying of solid particles using CFD. M.Sc. Thesis, Chalmers University of Technology, Sweden.
    Sutherland, W., 1893. LII. The viscosity of gases and molecular force. The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science, 36, 507-531. doi: 10.1080/14786449308620508.
    Syamlal, M., 1987. The particle-particle drag term in a multiparticle model of fluidization. Technical report, National Technical Information Service, West Virginia.
    Syamlal, M., Rogers, W., O’Brien, T.J., 1993. MFIX documentation theory guide. Technical report, National Technical Information Service, West Virginia.
    Thapa, R.K., Frohner, A., Tondl, G., Pfeifer, C., Halvorsen, B.M., 2016. Circulating fluidized bed combustion reactor: Computational Particle Fluid Dynamic model validation and gas feed position optimization. Comput. Chem. Eng. 92, 180-188. doi: 10.1016/j.compchemeng.2016.05.008.
    Utikar, R.D., Tade, N., Li, M., Evans, Q., Glenny, G., Pareek, V., 2010. Hydrodynamic simulation of cyclone separators. in: Oh, H.W. (Ed.), Computational Fluid Dynamics. InTechOpen, Croatia, pp. 241-266. doi: 10.5772/7106.
    Wan, G., Sun, G., Xue, X., Shi, M., 2008. Solids concentration simulation of different size particles in a cyclone separator. Powder Technol. 183 (1), 94-104. doi: 10.1016/j.powtec.2007.11.019.
    Wang, X.Y., Lei, J., Xu, X., Ma, Z.Z., Xiao, Y.H., 2014. Simulation and experimental verification of a hydrodynamic model for a dual fluidized bed gasifier. Powder Technol. 256, 324-335. doi: 10.1016/j.powtec.2014.01.087.
    Wen, C.Y., Yu, Y.H., 1966. A generalized method for prediction of the minimum fluidization velocity. AIChE J. 12 (3), 610-612. doi: 10.1002/aic.690120343.
    Xiang, R.B., Lee, K.W., 2005. Numerical study of flow field in cyclones of different height. Chem. Eng. Process. 44, 877-883. doi: 10.1016/j.cep.2004.09.006.
    Xiang, R.B., Lee, K.W., 2008. Effects of exit tube diameter on the flow field in cyclones. Part. Sci. Technol. 26 (5), 467-481. doi: 10.1080/02726350802367829.
    Xu, G., Murakami, T., Suda, T., Matsuzawa, Y., Tani, H., 2006. The superior technical choice for dual fluidized bed gasification. Ind. Eng. Chem. Res. 45 (7), 2281-2286. doi: 10.1021/ie051099r.
    Yang, S., Yang, H., Zhang, H., Li, J., Yue, G., 2009. Impact of operating conditions on the performance of the external loop in a CFB reactor. Chem. Eng. Process. Process Intensif. 48 (4), 921-926. doi: 10.1016/j.cep.2008.12.004.
    Zhang, Y.W., Chao, Z.X., Jakobsen, H.A., 2017. Modelling and simulation of hydrodynamics in double loop circulating fluidized bed reactor for chemical looping combustion process, Powder Technol. 310, 35-45. doi: 10.1016/j.powtec.2017.01.028.
    Zhou, X.Y., Gao, J.S., Xu, C.M., Lan, X.Y., 2013. Effect of wall boundary condition on CFD simulation of CFB risers. Particuology 11 (5), 556-565. doi: 10.1016/j.partic.2012.08.006.

    QR CODE
    :::