Back
 OJFD  Vol.7 No.1 , March 2017
Effect on the Flow Behaviors by Adding Internals in a Riser Reactor
Abstract: Riser reactor is a key unit in the Fluid Catalytic Cracking (FCC), and it has important influences on increasing the yield coefficient of gas and oil. In this paper, the behaviors of gas-solid two-phase flow in the traditional y-type riser reactor are investigated by numerical simulation. The calculated particle concentration distribution is in good agreement with the experimental data, which verified the advanced models and calculating methods. The non-uniform distribution, such as core-annulus flow, may result in the unreasonable matching relationship of catalyst-to-oil ratio. An optimized riser with cuneal internals is proposed and the comparison of two different structures of riser reactor is presented. The comparison results show that the cuneal internals in the riser both can block effectively the slip down of the particles near wall region and weaken core-annulus flow structure due to the redistribution of particles. The results also prove that the particle concentration distribution becomes uniform along the axial and radial direction in the optimized riser by adding cuneal internals, which would be benefits for the catalytic cracking reactions.
Cite this paper: Feng, L. , Bu, Y. , Wang, J. , Mao, Y. and Men, Z. (2017) Effect on the Flow Behaviors by Adding Internals in a Riser Reactor. Open Journal of Fluid Dynamics, 7, 72-82. doi: 10.4236/ojfd.2017.71005.
References

[1]   Glicksman, L.R., Hyre, M.R. and Farrell, P.A. (1994) Dynamic Similarity in Fluidization. International Journal of Multiphase Flow, 20, 331-386.
https://doi.org/10.1016/0301-9322(94)90077-9

[2]   Chen, Y.M. (2006) Recent Advances in FCC Technology. Powder Technology, 163, 2-8.
https://doi.org/10.1016/j.powtec.2006.01.001

[3]   Huang, W.X., Qi, X.B., Pan, Y.L., et al. (2002) Local Solid-Particle Concentration and Flow Development in a Long CFB Riser. Journal of Chemical Engineering of Chinese Universities, 16, 626-631.

[4]   Fan, Y., Ye, S., Lu, C.X., et al. (2002) Gas-Solid Two Phase Flow in Feed Injection Zone of FCC Riser Reactors (I) Experimental Research. Journal of Chemical Industry and Engineering (China), 53, 1003-1008.

[5]   Rhodes, M.J., Zhou, S., Hirama, T., et al. (1991) Effects of Operating Conditions on Longitudinal Solids Mixing in a Circulating Fluidized Bed Riser. AIChE Journal, 37, 1450-1458.
https://doi.org/10.1002/aic.690371003

[6]   Kong, C.L., Huang, W.X., Pan, Y.L., et al. (2002) Experimental Investigation on Particle Velocities for Gas-Solid Two Phase Flow in a CFB Riser. Journal of Sichuan University, 34, 41-45.

[7]   Zheng, Y., Wan, X., Qian, Z., et al. (2001) Numerical Simulation of the Gas-Particle Turbulent Flow in Riser Reactor Based on k-ε-k p-ε p-Θ Two-Fluid Model. Chemical Engineering Science, 56, 6813-6822. https://doi.org/10.1016/S0009-2509(01)00319-0

[8]   Gao, J., Xu, C., Lin, S., et al. (2001) Simulations of Gas-Liquid-Solid 3-Phase Flow and Reaction in FCC Riser Reactors. AIChE Journal, 47, 677-692. https://doi.org/10.1002/aic.690470315

[9]   Benyahia, S., Syamlal, M. and O’Brien, T.J. (2007) Study of the Ability of Multiphase Continuum Models to Predict Core-Annulus Flow. AIChE Journal, 53, 2549-2568.
https://doi.org/10.1002/aic.11276

[10]   Li, J., Fan, Y.P., Lu, C.X., et al. (2013) Numerical Simulation of Influence of Feed Injection on Hydrodynamic Behavior and Catalytic Cracking Reactions in a FCC Riser under Reactive Conditions. Industrial & Engineering Chemistry Research, 52, 11084-11098.
https://doi.org/10.1021/ie400250c

[11]   Bi, H.T. (2002) Some Issues on Core-Annulus and Cluster Models of Circulating Fluidized Bed Reactors. Canadian Journal of Chemical Engineering, 80, 809-817.
https://doi.org/10.1002/cjce.5450800504

[12]   Fan, Y., Ye, S., Chao, Z., et al. (2002) Gas-Solid Two-Phase Flow in FCC Riser. AIChE Journal, 48, 1869-1887. https://doi.org/10.1002/aic.690480905

[13]   Chen, S., Fan, Y., Yan, Z., et al. (2016) CFD Simulation of Gas-Solid Two-Phase Flow and Mixing in a FCC Riser with Feedstock Injection. Powder Technology, 287, 29-42.
https://doi.org/10.1016/j.powtec.2015.09.005

[14]   Hoomans, B.P.B., Kuipers, J.A.M., Briels, W.J., et al. (1996) Discrete Particle Simulation of Bubble and Slug Formation in a Two-Dimensional Gas-Fluidised Bed: A Hard-Sphere Approach. Chemical Engineering Science, 51, 99-118. https://doi.org/10.1016/0009-2509(95)00271-5

[15]   Benyahia, S., Arastoopour, H., Knowlton, T.M., et al. (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 Technology, 112, 24-33.
https://doi.org/10.1016/S0032-5910(99)00302-2

[16]   Liu, Y., Lu, H., Liu, W., et al. (2003) Model and Simulation of Gas-Solids Flow with Wide Size Distributions in Circulating Fluidized Beds. Journal of Chemical Industry & Engineering, 54, 1065-1071.

[17]   Mao, Y., et al. (2006) A New Internals to Weaken the Core-Annulus Flow in the Riser Reactor. CN200810055684.X.

[18]   Ferziger, J.H. and Perić, M. (1996) Computational Methods for Fluid Dynamics, Springer, Berlin.
https://doi.org/10.1007/978-3-642-97651-3

[19]   Nallasamy, M. (1987) Turbulence Models and Their Applications to the Prediction of Internal Flows: A Review. Computers & Fluids, 15, 151-194.
https://doi.org/10.1016/S0045-7930(87)80003-8

 
 
Top