CFD–PBE numerical simulation of CO2 capture using MgO-based sorbent

• A novel regenerative SEWGS process in a circulating fluidized bed has been proposed.
• The process is based on a new MgO-based solid sorbent.
• A coupled CFD–PBM approach is introduced for the fluidized bed reactor simulations.
• The PBM numerical solution is based on the finite size domain complete set of trial functions method of moment.

In this work a novel regenerative sorption enhanced water gas shift (SEWGS) process for high temperature and high pressure CO2 removal from Syngas in a circulating fluidized bed has been proposed. The process is based on an MgO-based solid sorbent. The major advantages of this sorbent include reducing the amount of WGS catalyst required to fully shift the Syngas to CO2 and H2 and eliminating Syngas cooling/reheating that is necessary for current CO2 separation systems. Another goal of this study was to improve the existing mono-disperse continuum models, i.e., Eulerian-Granular models that describe multiphase systems such as fluidized bed reactors, by considering the effect of poly-dispersity through a novel mathematical approach. As a result, a two-way coupled Computational Fluid Dynamics–Population Balance Model (CFD–PBM) along with an efficient numerical solution for the population balance equation has been proposed. The coupled CFD–PBM model along with the two-zone variable diffusivity shrinking core reaction model was utilized in baseline design of a bench scale high temperature, high pressure regenerative carbon capture process in the riser section of a circulation fluidized bed.

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