The Ca-Cu looping process using natural CO2 sorbents in a packed bed: Operation strategies to accommodate activity decay

Abstract

The Ca-Cu looping process is a promising CO2 capture technology designed to produce H2 and power from a fuel gas. The use of inexpensive and widely available limestone would facilitate the scale up of this technology. This work proposes a novel strategy for packed-bed Ca-Cu looping processes consisting of loading the sufficient amount of CuO to calcine only a well-defined fraction of CaCO3 in every cycle during the transient period until the limestone reaches a residual solid conversion of 0.06 (typically after 150–200 cycles). In this way, the excess of CaCO3 in the bed ensures temperatures below 900 °C during operation. The feasibility of this strategy is simulated for the conversion of blast furnace gas (BFG) into a H2-rich product (35 vol%) diluted in N2 via the Ca-Cu looping process at 2 bar and temperatures between 600 and 850 °C, while a separated CO2 rich gas (55 vol% CO2 in N2) is obtained.