Study of MgO-based dry regenerable sorbent for sorption enhanced water gas shift reaction

摘要

CO_2 sorption capacities and physical properties of the MgO-based sorbent, and the effect of steam during the sorbent regeneration were studied. Four MgO-based dry regenerable sorbents (P-A ~ D) were prepared by spray drying method for the application to pre-combustion CO_2 capture. Physical properties of the sorbents were measured by standard ASTM methods. MgO-based sorbents satisfied with most of the physical requirements for commercial fluidized-bed process. All sorbents had a spherical shape and an average size of 106 ± 10 urn. Most of the attrition index (Al) of the sorbents except for P-D was below 12%, which was superior, compared to commercial fluidized catalytic cracking (FCC) catalysts. CO_2 sorption capacities were evaluated by multi-cycle test in a high pressure bubbling fluidized-bed reactor at 473 K and 20 bar with 37% CO_2. The sorption capacities of the sorbents showed 3.3-14.5 wt% during 3 cycle. Particularly, P-A showed a high CO_2 sorption capacity of more than 14 wt%. In this study, CO_2 sorption capacity of steam-treated sorbent was higher than non-treated sorbent. This result can be explained by the presence of Mg(0H)_2 formed by hydroxylation by MgO and increasing surface area of steam-treated sorbent.