CFD-DEM Modeling of CO2 Capture using Alkali Metal-Based Sorbents in a Bubbling Fluidized Bed

Abstract

This paper describes a CFD-DEM modeling of CO 2 capture using K 2 CO 3 solid sorbents in a bubbling fluidized bed, which takes into heat transfer, hydrodynamics, and chemical reactions. Shrinking core model is applied in reaction kinetics. Simulation and experiment results of bed pressure drop and CO 2 concentration in the reactor exit agree well. Instantaneous dynamics as well as time-averaged profiles indicate detailed characteristics of gas flow, particle motion, and chemical reaction processes. The simulation results show an obvious coreannular flow and strong back-mixing flow pattern. CO 2 concentration decreases gradually along the bed height, while regards on the lateral distribution CO 2 concentration near the wall is lower than that in the middle zone where gas passes through faster. The effect of bubbles on CO 2 reaction is two-sided: it can promote mixing which strengthens reaction, while it can be a short pass of gas which is not beneficial to reaction. The simulation is helpful for further understanding and optimal design of fluidized bed reactors of CO 2 capture.

Numerical simulation on adsorption of CO2 using K2CO3 particles in the bubbling fluidized bed

“…The results showed that CO 2 conversion mainly occurred in the early stage of the reaction, and with the increase of gas flow rate, the gasification time was greatly shortened. Zhang et al 27 developed a CFD‐DEM model for the capture of CO 2 by K 2 CO 3 solid adsorbent in a BFB. The study revealed that bubbles can promote mixing and enhance the reaction yet are detrimental to the short‐path gas reaction.…”

A Novel, Coupled CFD-DEM Model for the Flow Characteristics of Particles Inside a Pipe

“…Shan et al [21] presented a coupled CFD-DEM analysis on the impact behaviour of a granular flow falling from an inclined slope into a water reservoir. Zhang et al [22] used a CFD-DEM modelling of CO 2 capture using K 2 CO 3 solid sorbents in a bubbling fluidized bed. The simulation results of the bed pressure drop and CO 2 concentration in the reactor exit agreed well with the experimental results, with the simulation results showing clear core-annular and strong back-mixing flow patterns.…”