Powder Technology, Vol.380, 462-474, 2021
Flow behavior and heat transfer in bubbling fluidized-bed with immersed heat exchange tubes for CO2 methanation
This study aims to investigate hydrodynamic and heat transfer characteristics of a BFB reactor with immersed heat exchange tubes for CO2 methanation using a two-dimensional (2D) gas-solid Eulerian computational fluid dynamics (CFD) model. A reaction kinetics model for Ni-based catalyst was coupled with the CFD model. The 2D-CFD model with the Huilin and Gidaspow drag was validated with experimental data for the bed expansion of Geldart B particles according to gas velocity. It was demonstrated that the heat of reaction was effectively removed in the BFB reactor with a 25% heat exchange area and that the reactor maintained isotherm conditions. The CO2 conversion was 92% in the BFB reactor at 400 degrees C and 5 bar. The overall heat transfer coefficient from the bed to the heat exchange tubes was estimated at 114 W/m(2)/K for an inlet gas velocity of 0.13 m/s. (C) 2020 Elsevier B.V. All rights reserved.
Keywords:Power-to-gas (PtG);CO2 methanation;Bubbling fluidized bed (BFB);Immersed heat exchange tubes;Computational fluid dynamics (CFD);Heat transfer coefficient