Effect of the Cross-Sectional Geometry on Heat Transfer and Particle Motion of Circulating Fluidized Bed Riser for CO2 Capture

Authors: Seungyeong Choi, Namkyu Lee, Dong Il Shim, Young Mun Lee, Yong-Ki Park, Hyung Hee Cho

Abstract:

Effect of the cross-sectional geometry on heat transfer and particle motion of circulating fluidized bed riser for CO₂ capture was investigated. Numerical simulation using Eulerian-eulerian method with kinetic theory of granular flow was adopted to analyze gas-solid flow consisting in circulating fluidized bed riser. Circular, square, and rectangular cross-sectional geometry cases of the same area were carried out. Rectangular cross-sectional geometries were analyzed having aspect ratios of 1: 2, 1: 4, 1: 8, and 1:16. The cross-sectional geometry significantly influenced the particle motion and heat transfer. The downward flow pattern of solid particles near the wall was changed. The gas-solid mixing degree of the riser with the rectangular cross section of the high aspect ratio was the lowest. There were differences in bed-to-wall heat transfer coefficient according to rectangular geometry with different aspect ratios.

Keywords: Bed geometry, computational fluid dynamics, circulating fluidized bed riser, heat transfer.

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1317260

References:

[1] N. MacDowell, N. Florin, A. Buchard, J. Hallett, A. Galindo, G. Jackson, C.S. Adjiman, C.K. Williams, N. Shah, P. Fennell, “An overview of CO2 capture technologies”, Energy & Environmental Science. vol., 3, 2010, pp. 1645.
[2] C.-H. Yu, A “Review of CO2 Capture by Absorption and Adsorption”, Aerosol and Air Quality Research, 2012.
[3] H.T. Bi, N. Ellis, I.A. Abba, J.R. Grace, “A state-of-the-art review of gas–solid turbulent fluidization”, Chemical Engineering Science., vol. 55, 2000, pp. 4789–4825.
[4] H. Moon, H. Yoo, H. Seo, Y.-K. Park, H.H. Cho, “Thermal design of heat-exchangeable reactors using a dry-sorbent CO2 capture multi-step process”, Energy, vol. 84, 2015, pp. 704–713.
[5] H. Yoo, H. Moon, H. Seo, Y.K. Park, H.H. Cho, “Effect of a diffuser on gas-solid behavior in CFB riser for CO2 capture”, Journal of Mechanical Science and Technology, vol. 30, 2016, pp. 3661–3666.
[6] S. Choi, H. Yoo, H. Moon, Y.-K. Park, H.H. Cho, “Heat transfer and gas-solid behaviors in pneumatic transport reactor used of carbon capture system”, Journal of Mechanical Science and Technology, vol. 31, 2017, pp. 5081–5087.
[7] H. Yoo, H. Moon, S. Choi, Y.-K. Park, H.H. Cho, “Effect of the jet direction of gas nozzle on the residence time distribution of solids in circulating fluidized bed risers”, Journal of the Taiwan Institute of Chemical Engineers, vol. 71, 2017, pp. 235–243.
[8] S.W. Kim, S.D. Kim, “Effects of particle properties on solids recycle in loop-seal of a circulating fluidized bed”, Powder Technology, vol. 124, 2002, pp. 76–84.
[9] M.J. Rhodes, S. Zhou, T. Hirama, H. Cheng, “Effects of operating conditions on longitudinal solids mixing in a circulating fluidized bed riser”, AIChE Journal, vol. 37, 1991, pp. 1450–1458.
[10] H. Moon, S. Choi, Y.-K. Park, H.H. Cho, “Thermal-fluid characteristics on near wall of gas-solid fluidized bed reactor”, International Journal of Heat and Mass Transfer, vol. 114, 2017, pp. 852–865.
[11] Y K Mohanty, G K Roy, K C Biswal, “Effect of column diameter onf dynamics of gas-solid fluized bed: A stastical approach”, Indian Journal of Chemical Technology, vol. 16, 2009, pp. 17–24.
[12] U. Arena, A. Marzocchella, L. Massimilla, A. Malandrino, “Hydrodynamics of circulating fluidized beds with risers of different shape and size”, Powder Technology, vol. 70, 1992, pp. 237–247.
[13] L.G. Gibilaro, R. Di Felice, S.P. Waldram, P.U. Foscolo, “Generalized friction factor and drag coefficient correlations for fluid-particle interactions”, Chemical Engineering Science, vol. 40, 1985, pp. 1817–1823
[14] D.J. Gunn, “Transfer of heat or mass to particles in fixed and fluidised beds”, International Journal of Heat and Mass Transfer, vol. 21, 1978, pp. 467–476.
[15] D. Geldart, “Types of gas fluidization, Powder Technology”, vol. 7, 1973, pp. 285–292.
[16] D. Gidaspow, R. Bezburuah, and J. Ding, "Hydrodynamics of Circulating Fluidized Beds, Kinetic Theory Approach", In Fluidization VII, Proceedings of the 7th Engineering Foundation Conference on Fluidization. 1992, pp. 75–82.
[17] C. K. K. Lun, S. B. Savage, D. J. Jeffrey, and N. Chepurniy, "Kinetic Theories for Granular Flow: Inelastic Particles in Couette Flow and Slightly Inelastic Particles in a General Flow Field", J. Fluid Mech, vol. 140, 1984, pp. 223–256.