Simulation study on the integration of water-gas shift and CO2-mineralization in a packed fluidized bed
A new continuous operation process was proposed for in-situ sequestrating the by-product CO2 of water-gas shift reaction(WGSR)by mineral carbonation(MC)in a packed fluidized bed.In addition to utilizing the high temperature,pressure,and humidity environment of WGSR to intensify MC,the continuous separation of sorbent powders by their fluidization through WGSR catalyst packed bed can cope with the rapid decay of MC absorption rate caused by thickening of the product layer.Based on the grain-scale solution-diffusion MC model and the WGSR apparent kinetics,a one-dimensional steady-state plug flow model of the reactor was established to analyze the technical and economic feasibility of applying this new process in a 750 MW integrated gasification combined cycle(IGCC)unit.The CO2 mitigation cost is calculated based on the simulated conversion rates of CO2 and MC sorbent,with given energy consumption,carbon tax,etc.It shows that obtaining added value from the carbonation product of MC sorbent as supplementary cementitious materials(SCM)is a prerequisite for the commercialization of this technology.Considering the conversion rates of CO2 and MC sorbent powder and the grinding energy consumption,MC sorbent fine powders of about 10 μm in diameter is preferred.