Dynamic modelling and optimal control strategies for chemical-looping combustion in an industrial-scale packed bed reactor

The transient operation of a Chemical-looping Combustion (CLC) process in a large-scale packed bed reactor (PBR) unit is presented in this study. This work adapts 1-D heterogeneous dynamic model that considers mass and heat transport resistances in the oxygen carrier particle and the bulk fluid phase. The proposed industrial-scale model was compared using data available in the open literature and was used to study optimal control strategies that can increase power production and reduce fuel slip during the oxidation and reduction stages of this process, respectively. Moreover, promising (optimistic) and pessimistic (worst-case) scenarios were considered for this process and used to demonstrate the operational flexibility of the packed bed reactor under different process operating conditions. Results from these scenarios show an extensive recovery heat process and a near full methane conversion into CO2 and H2O during the oxidation and reduction stages, respectively. Similarly, the purge stages were performed relatively fast using low amounts of purge gas. Therefore, the present study bolsters the importance of the CLC PBR process as an attractive carbon capture and sequestration (CCS) technology that can potentially reduce the energy penalty often entailed in CO2 capture and sequestration.