Three-dimensional CFD simulation of an MgO-based sorbent regeneration reactor in a carbon capture process

Abstract

Carbon dioxide is the primary greenhouse gas emitted through human activities; therefore, efficient reduction of CO2 is regarded as one of the key environmental challenges of the current century. Different processes have been introduced in the literature for CO2 capture; among these, solid sorbent processes have shown potential advantages such as easy regeneration and high capacity. In order to achieve steady CO2 capture using solid sorbents, a circulating fluidized bed (CFB) is used that consists mainly of a carbonator reactor (where the CO2 is adsorbed by solid sorbents) and a regenerator (where carbonated sorbents release CO2 and a concentrated CO2-steam mixture is produced). Different solid sorbents have been developed to be utilized in carbon capture units such as MgO-based sorbents and CaO-based sorbents. In this study, an MgO-based solid sorbent was used due to its capability to capture CO2 at high temperature (300–550°C), which is in the vicinity of the operating conditions of advanced power plants (e.g., integrated gasification combined cycles [IGCC]). The use of MgO-based sorbents results in a lower energy penalty in the carbonation/regeneration cycle of MgO-based sorbents. In this study, three-dimensional computational fluid dynamics (CFD) simulations of the regeneration unit of the carbon capture process using MgO-based solid sorbents were investigated and the performance of the fluidized bed regenerator unit (operating at different conditions) was studied.