Effects of internals on phase holdup and backmixing in a slightlyexpanded-bed reactor with gas-liquid concurrent upflow

doi:10.1016/j.cjche.2019.05.011

Chinese Journal of Chemical Engineering ›› 2019, Vol. 27 ›› Issue (10): 2273-2283.DOI: 10.1016/j.cjche.2019.05.011

• Fluid Dynamics and Transport Phenomena • Previous Articles Next Articles

Effects of internals on phase holdup and backmixing in a slightlyexpanded-bed reactor with gas-liquid concurrent upflow

Kang Yu^1,2, Weijie Wang^1,2, Tao Zhang³, Yumei Yong¹, Chao Yang^1,2

1 CAS Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China;
2 School of Chemical Engineering, University of Chinese Academy of Sciences, Beijing 100049, China;
3 PetroChina Petrochemical Research Institute, Beijing 102206, China

Received:2018-10-09 Revised:2019-04-07 Online:2020-01-17 Published:2019-10-28
Contact: Yumei Yong, Chao Yang
Supported by:
Supported by the National Key Research and Development Program (2016YFB0301701), the National Natural Science Foundation of China (21776283, 21427814), Key Research Program of Frontier Sciences of CAS (QYZDJ-SSW-JSC030), the Instrument Developing Project of Chinese Academy of Sciences (YZ201641) and PetroChina.

Effects of internals on phase holdup and backmixing in a slightlyexpanded-bed reactor with gas-liquid concurrent upflow

Kang Yu^1,2, Weijie Wang^1,2, Tao Zhang³, Yumei Yong¹, Chao Yang^1,2

1 CAS Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China;
2 School of Chemical Engineering, University of Chinese Academy of Sciences, Beijing 100049, China;
3 PetroChina Petrochemical Research Institute, Beijing 102206, China

通讯作者: Yumei Yong, Chao Yang
基金资助:
Supported by the National Key Research and Development Program (2016YFB0301701), the National Natural Science Foundation of China (21776283, 21427814), Key Research Program of Frontier Sciences of CAS (QYZDJ-SSW-JSC030), the Instrument Developing Project of Chinese Academy of Sciences (YZ201641) and PetroChina.

Abstract

Abstract: Five different internals were designed, and their effects on phase holdup and backmixing were investigated in a gas-liquid concurrent upflow reactor where the spherical alumina packing particles of three diameters (3.0, 4.5 and 6.0 mm) were slightly expanded under the conditions of varied superficial gas velocities (6.77×10^-2-3.61×10^-1 m·s^-1) and superficial liquid velocities (9.47×10^-4-2.17×10^-3 m·s^-1). The experimental results show that the gas holdup increases with the superficial gas velocity and particle size, opposite to the variational trend of liquid holdup. When an internal component is installed amid the upflow reactor, a higher gas holdup, a less liquid holdup and a larger Peclet number characterizing the weaker backmixing are obtained compared to those in the bed without internals under the same operating conditions. Additionally, the minimal backmixing is observed in the reactor equipped with the internals with a novel multi-step design. Finally, empirical correlations were proposed for estimating gas holdup, liquid holdup and Peclet number with the relative deviations within 11%, 12% and 25%, respectively.

Key words: Internals, Phase holdup, Backmixing, Slightly-expanded-bed reactor, Multiphase flow, Hydrodynamics

摘要： Five different internals were designed, and their effects on phase holdup and backmixing were investigated in a gas-liquid concurrent upflow reactor where the spherical alumina packing particles of three diameters (3.0, 4.5 and 6.0 mm) were slightly expanded under the conditions of varied superficial gas velocities (6.77×10^-2-3.61×10^-1 m·s^-1) and superficial liquid velocities (9.47×10^-4-2.17×10^-3 m·s^-1). The experimental results show that the gas holdup increases with the superficial gas velocity and particle size, opposite to the variational trend of liquid holdup. When an internal component is installed amid the upflow reactor, a higher gas holdup, a less liquid holdup and a larger Peclet number characterizing the weaker backmixing are obtained compared to those in the bed without internals under the same operating conditions. Additionally, the minimal backmixing is observed in the reactor equipped with the internals with a novel multi-step design. Finally, empirical correlations were proposed for estimating gas holdup, liquid holdup and Peclet number with the relative deviations within 11%, 12% and 25%, respectively.

关键词: Internals, Phase holdup, Backmixing, Slightly-expanded-bed reactor, Multiphase flow, Hydrodynamics

Kang Yu, Weijie Wang, Tao Zhang, Yumei Yong, Chao Yang. Effects of internals on phase holdup and backmixing in a slightlyexpanded-bed reactor with gas-liquid concurrent upflow[J]. Chinese Journal of Chemical Engineering, 2019, 27(10): 2273-2283.

References

[1] X.T. Wang, W.R. Li, H.X. Weng, J.D. Liu, S.R. Qi, Q.T. Ma, Research on slight expandedbed oil residue hydrotreating reactor, Chem. Eng. (Xi'an, China) 34(9) (2006) 28-31(in Chinese).
[2] M.R. Khadilkar, Y.X. Wu, M.H. Al-Dahhan, M.P. Dudukovic, M. Colakyan, Comparison of trickle-bed and upflow reactor performance at high pressure:model predictions and experimental observations, Chem. Eng. Sci. 51(10) (1996) 2139-2148.
[3] J.F. Chen, Green chemical engineering, Eng. 3(3) (2017) 283-284.
[4] M. Ji, Z. Yang, X.J. Lou, Y.M. Yong, C. Yang, Fluid flow and backmixing characteristics of up-flow reactor, Chem. Eng. (Xi'an, China) 43(11) (2015) 41-46(in Chinese).
[5] W.J. Wang, Y.M. Yong, C. Yang, K. Yu, Flow and back-mixing characteristics in three dimensional up-flow reactor, CIESC J. 69(1) (2018) 381-388(in Chinese).
[6] B. Hadi, J.R.V. Ommen, M.O. Coppens, Enhanced particle mixing in pulsed fluidized beds and the effect of internals, Ind. Eng. Chem. Res. 51(4) (2012) 1713-1720.
[7] R.N. Maiti, K.D.P. Nigam, Gas-liquid distributors for trickle-bed reactors:a review, Ind. Eng. Chem. Res. 46(19) (2007) 6164-6182.
[8] F. Bazer-Bachi, Y. Haroun, F. Augier, C. Boyer, Experimental evaluation of distributor technologies for trickle-bed reactors, Ind. Eng. Chem. Res. 52(32) (2013) 11189-11197.
[9] B.E. Reynolds, F.W. Lam, J. Chabot, F.J. Antezana, R. Bachtel, K.R. Gibson, R. Threlkel, P.C. Leung, Upflow reactor system with layered catalyst bed for hydrotreating heavy feedstocks, U.S. Pat., 6554994 B1(2003).
[10] S.L.P. Lee, H.I.D. Lasa, Phase holdups in three-phase fluidized beds, AICHE J. 33(8) (1987) 1359-1370.
[11] S. Rabha, M. Schubert, M. Wagner, D. Lucas, U. Hampel, Bubble size and radial gas hold-up distributions in a slurry bubble column using ultrafast electron beam Xray tomography, AICHE J. 59(5) (2013) 1709-1722.
[12] H.M. Jena, G.K. Roy, B.C. Meikap, Prediction of gas holdup in a three-phase fluidized bed from bed pressure drop measurement, Chem. Eng. Res. Des. 86(11) (2008) 1301-1308.
[13] Z.X. Chen, J. Yang, D. Ling, P. Liu, I.M.S.K. Ilankoon, Z.B. Huang, Z.M. Cheng, Packing size effect on the mean bubble diameter in a fixed bed under gas-liquid concurrent upflow, Ind. Eng. Chem. Res. 56(45) (2017) 13490-13496.
[14] A.M. Anter, Q. Xiao, Z.M. Cheng, W.K. Yuan, Liquid holdup measurements in downward flow and upward flow fixed-bed reactors, CIESC J. 51(4) (2000) 535-539(in Chinese).
[15] M. Cassanello, O. Martínez, A.L. Cukierman, Liquid hold-up and backmixing in cocurrent upflow three-phase fixed-bed reactors, Chem. Eng. Sci. 53(5) (1998) 1015-1025.
[16] J.G.G. Maldonado, D. Bastoul, S. Baig, M. Roustan, G. Hébrard, Effect of solid characteristics on hydrodynamic and mass transfer in a fixed bed reactor operating in cocurrent gas-liquid up flow, Chem. Eng. Process. 47(8) (2008) 1190-1200.
[17] M.F.P. Moreira, M.C. Ferreira, J.T. Freire, Total liquid saturation in gas-liquid cocurrent downflow and upflow through packed beds and analysis of correlations for predicting the total liquid saturation, Ind. Eng. Chem. Res. 43(4) (2004) 1096-1102.
[18] V. Sivakumar, G.S. Nirmala, T. Murugesan, Gas phase hold up in gas-liquid cocurrent upflow packed bed reactors at low Reynold's number, Bioprocess Eng. 21(1) (1999) 41-43.
[19] P. Therning, A. Rasmuson, Liquid dispersion and gas holdup in packed bubble columns at atmospheric pressure, Chem. Eng. J. 81(1-3) (2001) 69-81.
[20] F. Larachi, A. Laurent, G. Wild, N. Midoux, Some experimental liquid saturation results in fixed-bed reactors operated under elevated pressure in cocurrent upflow and downflow of the gas and the liquid, Ind. Eng. Chem. Res. 30(11) (1991) 2404-2410.
[21] H. Sindhu, P.S.T. Sai, A model for pressure drop and liquid saturation in gas-liquid cocurrent upflow through packed beds, Chem. Eng. J. 93(2) (2003) 135-142.
[22] A.K. Saroha, R. Khera, Hydrodynamic study of fixed beds with cocurrent upflow and downflow, Chem. Eng. Process. 45(6) (2006) 455-460.
[23] E.J. Molga, K.R. Westerterp, Experimental study of a cocurrent upflow packed bed bubble column reactor:pressure drop, holdup and interfacial area, Chem. Eng. Process. 36(6) (1997) 489-495.
[24] E.J. Molga, K.R. Westerterp, Gas-liquid interfacial area and holdup in a cocurrent upflow packed bed bubble column reactor at elevated pressures, Ind. Eng. Chem. Res. 36(3) (1997) 622-631.
[25] J.H.P. Collins, A.J. Sederman, L.F. Gladden, M. Afeworki, J.D. Kushnerick, H. Thomann, Characterising gas behaviour during gas-liquid co-current up-flow in packed beds using magnetic resonance imaging, Chem. Eng. Sci. 157(2017) 2-14.
[26] V. Alexander, H. Albazzaz, M. Al-Dahhan, Gas phase dispersion/mixing investigation in a representative geometry of gas-liquid upflow moving bed hydrotreater reactor (MBR) using developed gas tracer technique and method based on convolution/regression, Chem. Eng. Sci. 195(2019) 671-682.
[27] S. Kumar, R.A. Kumar, P. Munshi, A. Khanna, Gas hold-up in three phase co-current bubble columns, Procedia Eng. 42(2012) 782-794.
[28] A. Attou, G. Ferschneider, A simple model for pressure drop and liquid hold-up in packed-bed bubble reactors, Chem. Eng. Sci. 54(21) (1999) 5139-5144.
[29] A. Montagna, Y.T. Shah, Backmixing effect in an upflow cocurrent hydrodesulfurization reactor, Chem. Eng. J. 10(1) (1975) 99-105.
[30] T. Burkhardt, J. Verstraete, P. Galtier, M. Kraume, Residence time distributions with a radiotracer in a hydrotreating pilot plant:upflow versus downflow operation, Chem. Eng. Sci. 57(11) (2002) 1859-1866.
[31] Z.S. Mao, J.Y. Chen, Chemical Reaction Engineering Fundamentals, Science Press, Beijing, 2004(in Chinese).
[32] P.V. Danckwerts, Continuous flow systems, distribution of residence times, Chem. Eng. Sci. 2(1) (1953) 1-13.
[33] O. Levenspiel, W.K. Smith, Notes on the diffusion-type model for the longitudinal mixing of fluids in flow, Chem. Eng. Sci. 6(4-5) (1957) 227-233.
[34] M.L. Bordas, A. Cartellier, P. Sechet, Ch. Boyer, Bubbly flow through fixed beds:micro-scale experiments in the dilute regime and modelling, AICHE J. 52(11) (2006) 3722-3743.
[35] M.H. Al-Dahhan, H. Al-Bazzaz, V. Alexander, A. Toukan, Recent advances on the hydrodynamics of two-phase flow moving bed for catalytic hydrotreating:Experimentation and computing investigations, The 10th International Symposium on Catalysis in Multiphase Reactors (CAMURE-10) and the 9th International Symposium on Multifunctional Reactors (ISMR-9), 2017, Qingdao.
[36] S.O. Rastegar, T.Y. Gu, Empirical correlations for axial dispersion coefficient and Peclet number in fixed-bed columns, J. Chromatogr. A 1490(2017) 133-137.

Effects of internals on phase holdup and backmixing in a slightlyexpanded-bed reactor with gas-liquid concurrent upflow

Effects of internals on phase holdup and backmixing in a slightlyexpanded-bed reactor with gas-liquid concurrent upflow

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