Solid Concentration in Circulating Fluidized Bed Reactor for the MTO Process

Authors: Biao Wang, Tao Li, Qi-wen Sun, Wei-yong Ying, Ding-ye Fang

Abstract:

Methanol-to-olefins (MTO) coupled with transformation of coal or natural gas to methanol gives an interesting and promising way to produce ethylene and propylene. To investigate solid concentration in gas-solid fluidized bed for methanol-to-olefins process catalyzed by SAPO-34, a cold model experiment system is established in this paper. The system comprises a gas distributor in a 300mm internal diameter and 5000mm height acrylic column, the fiber optic probe system and series of cyclones. The experiments are carried out at ambient conditions and under different superficial gas velocity ranging from 0.3930m/s to 0.7860m/s and different initial bed height ranging from 600mm to 1200mm. The effects of radial distance, axial distance, superficial gas velocity, initial bed height on solid concentration in the bed are discussed. The effects of distributor shape and porosity on solid concentration are also discussed. The time-averaged solid concentration profiles under different conditions are obtained.

Keywords: Branched pipe distributor, distributor porosity, gas-solid fluidized bed, solid concentration.

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1332082

References:

[1] A. Izadbakhsh, F. Farhadi, F. Khorashe, "Effect of SAPO-34-s composition on its physico-chemical properties and deactivation in MTO process", Appl. Catal., A, vol. 364, pp. 48-56, 2009.
[2] X. C. Wu, M. G. Abraha, R. G. Anthony, "Methanol conversion on SAPO-34: reaction condition for fixed-bed reactor", Appl. Catal., A, vol. 260, pp. 63-73, 2004.
[3] B. V. Vora, T. L. Marker, P. T. Barger, H. E. Fullerton, H. P. Nilson, S. Kvisle, T. Fuglerud, "Economic route for natural gas conversion to ethylene and propene", Stud. Surf. Sci. Catal., vol. 107, pp. 87-92, 1997.
[4] H. Q. Zhou, Y. Wang, F. Wei, D. Z. Wang, Z. W. Wang, "In situ synthesis of SAPO-34 crystals grown onto a-Al2O3 sphere supports as the catalyst for the fluidized bed conversion of dimethyl ether to olefins", Appl. Catal., A, vol. 341, pp. 112-118, 2008.
[5] H. Y. Zhu, J. Zhu, "Gas-Solids Flow Structures in a Novel Circulating Turbulent Fluidized Bed", AIChE. J, vol. 54, no. 5, pp. 1213-1221, 2008.
[6] Y. P. Li, B. J. Ma, J. B. Hu, K. Zhao, "Numerical Simulation of the Hydrodynamics of Gas/Solid Two-Phase Flow in a Circulating Fluidized Bed with Different Inlet Configurations", Chem. Eng. Tech., vol. 32, no. 6, pp. 964-965, 2009.
[7] W. Q. Zhong, Y. Zhang, B. S. Jin, M. Y. Zhang, "Discrete Element Method Simulation of Cylinder-Shaped Particle Flow in a Gas-Solid Fluidized Bed", Chem. Eng. Tech., vol. 32, pp. 386-396, 2009.
[8] J. J. Nieuwland, R. Meijer, J. A. M. Kuipers, W. P. M. van Swaaij, "Measurements of solids concentration and axial solids velocity in gas-solid two-phase flows", Powder Technol., vol. 87, pp. 127-137, 1996.
[9] D. Tayebi, H. F. Svendsen, A. Grislingås, T. Majdell, K. Johannessen, "Dynamics of luidized-bed reactors: development and application of a new multi-optical fiber probe", Chem. Eng. Sci., vol. 54, pp. 2113-2123, 1999.
[10] E. Taghipou, N. Ellis, C. Wong, "Experimental and Computational Study of Gas-solid Fluidized Bed Hydrodynamics", Chem. Eng. Sci., vol. 60, pp. 6857-6867, 2005.
[11] L. J. Zhang, T. Li, W. Y. Ying, D. Y. Fang, "Experimental Study on Bubble Rising an Descending Velocity Distribution in a Slurry Bubble Column Reactor", Chem. Eng. Tech., vol. 31, no. 9, pp. 1362-1372, 2008.
[12] L. J. Zhang, T. Li, W. Y. Ying, D. Y. Fang, "Rising and descending bubble size distributions in gas-liquid and gas-liquid-solid slurry bubble column reactor", Chem. Eng. Res. Des., vol. 86, pp. 1143-1146, 2008.
[13] X. B. Qi, H. Zhang, J. Zhu, "Solids concentration in the fully developed region of circulating fluidized bed downers", Powder Technol., vol. 183, pp. 417-427, 2008.
[14] J.J. Nieuwland, R. Meijer, J.A.M. Kuipers, W.P.M. van Swaaij, "Measurements of solids concentration and axial solids velocity in gas-solids two-phase flows", Powder Technol., vol. 87, pp. 127-137, 1996.
[15] H. Zhang, P.M. Johnston, J. X. Zhu, H. I. D. e. Lasa, M. A. Bergougnou, "A novel calibration procedure for a fiber optic solids concentration probe", Powder Technol., vol. 100, pp. 260-270,1998.
[16] H. Johnsson, F. Johnsson, "Measurements of local solids volume-fraction in fluidized bed boilers", Powder Technol., vol. 115, pp. 13-18, 2001.
[17] F Wei, H Lin, Y Cheng, Y Jin, Z Yu, "Profiles of Particle Velocity and Solids Fraction in a High Density Riser", Powder Technol., vol. 100, pp. 183-193, 1998.
[18] D. Gidspow, B. Ettehadieh, "Fluidization in two dimensional beds with a jet: Part. Hydrodynamic modeling", Ind. Eng. Chem. Fundam., vol. 22, pp. 193-201, 1983.
[19] J. A. M. Kupiers, H. Tammes, W. Princs, W. P. M. van Swaaij, "Experimental and theoretical porosity profiles in two dimensional gas-fluidized bed with a central jet", Powder Technol., vol. 71, pp. 87-92, 1992.