Modeling long-time behaviors of industrial multiphase reactors for CO2 capture using CFD-based compartmental model

Abstract

Pilot- and industrial-scale mineral carbonation plants to remove CO2 through a reaction with Ca(OH)2 were built in South Korea to address concerns related to global warming. To simulate mineral carbonation reactors with complex gas–liquid–solid interacting flow patterns, a computational fluid dynamics (CFD)-based compartmental model was developed. In the model, the reactors were divided into hundreds of zones, and each zone was assumed to be a single homogeneous reactor. Mass and heat balance equations were formulated for each zone and the entire reactor, separately. The mass flow rates between adjacent zones and initial CO2 holdup at each zone were calculated from CFD simulations, and a kinetic model, which included all the involved reactions, was built in MATLAB. The total CO2 removal efficiency, pH, and temperature changes as well as concentration profiles of CO2 and other species were predicted during batch operations. To validate the performance of the model, the simulated results were compared with the real operation data from the pilot- and industrial-scale plants. The errors at steady states were within 7% without any adjustable parameters. Furthermore, the model was used to predict the performances of reactors 2.5 and 10 times larger than the industrial-scale reactor.