ارزیابی عملکرد یک رآکتور بستر سیال با بررسی هیدرودینامیک و خصوصیات گرمایی ذرات جامد مختلف

نوع مقاله : مقاله پژوهشی

نویسندگان

1 دانشکده مهندسی مکانیک، دانشگاه گیلان، رشت، ایران

2 گیلان*مهندسی مکانیک

چکیده

نرخ انتقال حرارت بالا به عنوان یکی از مزایای مهم رآکتورهای بستر سیال به فرآیندهای هیدرودینامیکی بستر وابسته است. در این تحقیق پارامترهای مهم هیدرودینامیکی از جمله حداقل سرعت شناوری، افت فشار، ارتفاع بستر و وضعیت بستر از نظر تشکیل حباب و رژیم جریان به صورت آزمایشگاهی و عددی بررسی گردید. مدل اویلری دو سیالی به همراه تئوری انرژی جنبشی جریان دانه‌ای و دو مدل درگ مختلف گیداسپا و سایملال-اوبراین در شبیه‌سازی عددی حاضر به کار گرفته شد. نتایج نشان داد که با استفاده از مدل درگ گیداسپا در حل عددی، حداقل سرعت شناوری با خطای تقریبی 8/13 درصد و ارتفاع بستر با متوسط خطای 9 درصد نسبت به کار آزمایشگاهی قابل پیش‌بینی است. به منظور بررسی تأثیر خصوصیات ذرات بر توزیع دمای بستر سیال‌های حبابی، ذرات جامد مختلف با چگالی و ضرایب پخشندگی گرمایی متفاوت مورد بررسی قرار گرفتند. در نهایت برای اثبات مزیت استفاده از رآکتورهای بستر سیال برای دریافت هوای گرم مورد نیاز در واحدهای صنعتی، توزیع دما و ارتفاع یک رآکتور بستر سیال حبابی و کانال ساده‌ی دما ثابت در شرایط یکسان مقایسه گردید. نتایج نشان داد که دمای هوای خروجی از یک رآکتور بستر سیال حبابی تقریباً 28 درجه سلسیوس بیشتر از کانال ساده‌ی مشابه است.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Performance Evaluation of a Fluidized Bed Reactor by Studying the Hydrodynamics and Thermal Properties of Different Solid Particles

نویسندگان [English]

  • Soodeh Torfeh 1
  • Ramin Kouhi Kamali 2
1 Department of Mechanical Engineering, University of Guilan, Rasht, Iran
چکیده [English]

High heat transfer rate as one of the important advantages of fluidized bed reactors is attributed to hydrodynamic mechanisms. In this research the important hydrodynamic parameters such as minimum fluidization velocity, pressure drop, bed height, bubble formation and flow regime were investigated experimentally and numerically. The two-fluid model coupled with the kinetic theory of granular flow and two different drag models of Gidaspow and Syamlal-O'Brien were applied in the present simulation. The results showed that by using the Gidaspow drag model in numerical solution, the minimum fluidization velocity with an approximate error of 13.8% and the bed height with an average error of 9% are predictable in comparison with the experiments. In order to investigate the effects of particles properties on temperature distribution of a bubbling fluidized bed, several solid particles with different densities and thermal diffusivities were investigated. Finally, to demonstrate the advantages of fluidized beds to receive the required hot air in industrial units, temperature distribution and required height of a bubbling fluidized bed reactor were compared with a similar constant surface temperature simple channel. The results showed that the outlet air temperature of a bubbling fluidized bed is about 28 degrees Celsius higher than a similar simple channel.

کلیدواژه‌ها [English]

  • Gas-solid fluidized bed
  • Two-fluid model
  • Hydrodynamic behavior
  • Thermal diffusivity coefficient
  • Temperature distribution
[1] H. Kruggel-Emden, K. Vollmari, Flow-regime transitions in fluidized beds of non-spherical particles, Particuology, 29 (2016) 1-15.
[2] Y. Behjat, S. Shahhosseini, H. Hashemabadi, CFD modeling of hydrodynamic and heat transfer in fluidized bed reactors, International Communication in Heat and Mass Transfer, 35 (2008) 357-368.
[3] D. Kunii, O. Levenspiel, Fluidization Engineering, Second edition ed., Butterworth-Heinemann, Boston, 1991.
[4] R. Yusuf, M.C. Melaaen, V. Mathiesen, Convective heat and mass transfer modeling in gas-fluidized beds, Chemical Engineering & Technology, 28(1) (2005) 13-24.
[5] S. Karimipour, T. Pugsley, A critical evaluation of literature correlations for predicting bubble size and velocity in gas–solid fluidized beds, Powder Technology, 205 (2011) 1-14.
[6] K. Suksankraisorn, S. Patumsawad, B. Fungtmmasan, Prediction of minimum fluidization velocity from correlations: An observation, Asian Journal on Energy and Environment, 2(2) (2001) 145-154.
[7] H.M. Abdelmotalib, M.A.M. Youssef, A.A. Hassan, S.B. Youn, I.T. Im, Heat transfer process in gas-solid fluidized bed combustors: a review, International Journal of Heat and Mass Transfer, 89 (2015) 567-575.
[8] Y. Wang, Z. Zou, H. Li, Q. Zhu, A new drag model for TFM simulation of gas-solid bubbling fluidized beds with Geldart-B particles, Particuology, 15 (2014) 151-159.
[9] B.G.M.V. Wachem, J.V.d. Schaaf, J.C. Schouten, R. Krishna, C.M.v.d. Bleek, Experimental validation of Lagrangian-Eulerian simulations of fluidized beds, Powder Technology, 116 (2001) 155-165.
[10] F. Taghipour, N. Ellis, C. Wong, Experimental and computational study of gas-solid fluidized bed hydrodynamics, Chemical Engineering Science, 60 (2005) 6857-6867.
[11] M.R. Ajay, A. Karnik, Numerical investigation of the effect of bed height on minimum fluidization velocity of cylindrical fluidized bed, in:  International Congress on Computational Mechanics and Simulation, 2012.
[12] M. Mostafazadeh, H. Rahimzadeh, M. Hamzei, Numerical analysis of the mixing process in a gas-solid fluidized bed reactor, Powder Technology, 239 (2013) 422-433.
[13] A. Bakshi, C. Altantzis, R.B. Bates, A.F. Ghoniem, Eulerian-Eulerian simulation of dense solid-gas cylindrical fluidized beds: Impact of wall boundary condition and drag model on fluidization, Powder Technology, 277 (2015) 47-62.
[14] D. Gidaspow, Multiphase Flow and Fluidization: Continuum and Kinetic Theory Descriptions, Academic Press, Boston, USA, 1994.
[15] M. Syamlal, T.J. O'Brien, Computer Simulation of Bubbles in a Fluidized Bed, American Institute of Chemical Engineers Symposium Series, 85 (1989) 22-31.
[16] R. Permatasari, T.M. Lazim, T. Sukarnoto, Supriyadi, Fluidization of gas-solid in atmospheric bubbling fluidized bed combustor, Applied Mechanics and Materials, 819 (216) 265-271.
[17] L. Chen, X. Yang, G. Li, J. Yang, C. Wen, X. Li, C. Snape, Dynamic modelling of fluidisation in gas-solid bubbling fluidised beds, Powder Technology, 322 (2017) 461-470.
[18] P. Ostermeier, A. Vandersickel, S. Gleis, H. Spliethoff, Three dimensional multi fluid modeling of Geldart B bubbling fluidized bed with complex inlet geometries, Powder Technology, 312 (2017) 89-102.
[19] M. Mehdizad, R. Kouhikamali, Numerical investigation of the minimum fluidization velocity in a gas–solid fluidized bed using discrete phase model, Journal of the Brazilian Society of Mechanical Sciences and Engineering, 40 (2018) 272-288.
[20] Y. Kurosaki, I. Satoh, T. Ishize, Mechanisms of heat transfer enhancement of gas-solid fluidized bed: Estimation of direct contact heat exchange from heat transfer surface to fluidized particles using an optical visualization technique, Transactions ASME, 117 (1995) 104-112.
[21] N.I. Gelperin, V.G. Einstein, Heat transfer in fluidized beds, in Fluidization, Academic press, New York, 1971.
[22] D.J. Gunn, Transfer of heat or mass to particles in fixed and fluidized beds, International Journal of Heat and Mass Transfer, 21 (1978) 467-476.
[23] J.L.M.A. Gomes, C.C. Pain, C.R.E.d. Oliveira, A.J.H. Goddard, F.B.S. Oliveira, A numerical investigation of heat transfer mechanisms in gas-solid fluidized beds using the two-fluid granular temperature model, Heat Transfer Engineering, 28 (2007) 576-597.
[24] M. Hamzehei, H. Rahimzadeh, Experimental and numerical study of hydrodynamics with heat transfer in a gas-solid fluidized-bed reactor at different particle sizes, Industrial & Engineering Chemistry Research, 48 (2009) 3177-3186.
[25] J. Chang, G. Wang, J. Gao, K. Zhang, H. Chen, Y. Yang, CFD modeling of particle-particle heat transfer in dense gas-solid fluidized beds of binary mixture, Powder Technology, 217 (2012) 50-60.
[26] H.M. Abdelmotalib, D.G. Ko, T.T. Im, A study on wall-to-bed heat transfer in a conical fluidized bed combustor, Applied Thermal Engineering, 25 (2016) 928-937.
[27] Q.F. Hou, Z.Y. Zhou, A.B. Yu, Gas-solid flow and heat transfer in fluidized beds with tubes: Effects of material properties and tube array settings, Powder Technology, 296 (2016) 59-71.
[28] P. Ostermeier, F. Dawo, A. Vandersickel, S. Gleis, H. Spliethoff, Numerical calculation of wall-to-bed heat transfer coefficients in Geldart B bubbling fluidized beds with immersed horizontal tubes, Powder Technology, 333 (2018) 193-208.
[29] D. Geldart, Types of Gas Fluidization, Powder Technology, 7 (1973) 285-292.
[30] C.Y. Wen, Y.H. Yu, A generalized method for predicting the minimum fluidization velocity, AIChE Journal, 12(3) (1966) 610-612.
[31] M. Leva, Fluidization, McGraw Hill, New York, 1959.
[32] S.C. Saxena, G.J. Vogel, The measurement of incipient fluidization velocities in a bed of course dolomite at temperature and pressure, Transaction of Institution of Chemical Engineers, 55 (1977) 184-189.
[33] O.M. Todes, R.B. Goroshkov, R.B. Rozenbaum, Izv. Vyssh. Uchcbn. Zaved. , Neft Gaz, 1 (1958).
[34] L. Davies, J.F. Richardson, Gas interchange between bubbles and the continuous phase in a fluidized bed, Transaction of Institution of Chemical Engineers, 44 (1966) 293-305.
[35] J.L. Lee, E.W.C. Lim, Comparisons of Eulerian-Eulerian and CFD-DEM simulations of mixing behaviors in bubbling fluidized beds, Powder Technology, 318 (2017) 193-205.
[36] Y. He, S. Yan, T. Wang, B. Jiang, Y. Huang, Hydrodynamic characteristics of gas-irregular particle two-phase flow in a bubbling fluidized bed: An experimental and numerical study, Powder Technology, 287 (2016) 264-276.
[37] C. Loha, H. Chattopadhyay, P.K. Chatterjee, Euler-Euler CFD modeling of fluidized bed: Influence of specularity coefficient on hydrodynamic behavior, Particuology, 11 (2013) 673-680.
[38] J. Ngoh, E.W.C. Lim, Effects of particle size and bubbling behavior on heat transfer in gas fluidized beds, Applied Thermal Engineering, 105 (2016) 225-242.
[39] R. Yusuf, B. Halvorsen, M.C. Melaaen, An experimental and computational study of wall to bed heat transfer in a bubbling gas-solid fluidized bed, International Journal of Multiphase Flow, 42 (2012) 9-23.
[40] D. Perrone, M. Amelio, A preliminary study of hydrodynamics and heat transfer in a bubbling fluidized bed containing sand particle using CFD, Energy Procedia, 81 (2015) 1041-1054.
[41] A. Schmidt, U. Renz, Numerical prediction of heat transfer in fluidized beds by a kinetic theory of granular flows, International Journal of Thermal Sciences, 39 (2000) 871-885.
[42] H.M. Abdelmotalib, M.A.M. Youssef, A.A. Hassan, S.B. Youn, I.T. Im, Numerical study on the wall to bed heat transfer in a conical fluidized bed combustor, International Journal of Precision Engineering and Manufacturing, 16(7) (2015) 1551-1559.
[43] D. Gidaspow, M. Syamlal, Hydrodynamics of fluidization: Prediction of wall to bed heat transfer coefficients, American Institute of Chemical Engineers Journal, 31(1) (1985) 127-135.
[44] J.A.M. Kuipers, W. Prins, W.P.M.V. Swaaij, Calculation of wall-to-bed heat-transfer coefficients in gas-fluidized beds, American Institute of Chemical Engineers Journal, 38 (1992) 1079-1091.
[45] P.C. Johnson, R. Jackson, Frictional-collisional constitutive relations for granular materials, with application to plane shearing, Journal of Fluid Mechanics, 176 (1987) 67-93.
[46] M. Hamzehei, H. Rahimzadeh, G. Ahmadi, Study of Heat Transfer and Hydrodynamics in a Gas-Solid Fluidized Bed Reactor Experimentally and Numerically, Applied Mechanics and Materials, 110-116 (2012) 4187-4197.
[47] R.I. Singh, A. Brink, M. Hupa, CFD modeling to study fluidized bed combustion and gasification, Applied Thermal engineering, 52 (2013) 585-614.
[48] H.W. Li, H. Guo, Analysis of drying characteristics in mixed pulsed rectangle fluidized beds, Powder Technology, 308 (2017) 451-460.