Study of lime flow rate on calcium looping carbon capture for steel plant

Abstract

Calcium looping carbon capture was simulated for a steel plant and three fuel cases were studied: coal, coke, and half coal/coke. The steelmaking production was about 1.2 t of liquid steel per hour at >99.85% purity by weight. This study evaluated the effect of carbon capture efficiency and raw material cost on the lime flow rate in the calcium looping section. Increasing the lime feeding flow rate achieved higher efficiency but at a higher cost. The overall captured efficiency was higher than the flue gas captured efficiency at a low lime feeding flow rate but lower at a high lime feeding flow rate. Then, the overall captured efficiency tended to decrease at high lime feeding flow rate because raw materials were used too much for carbon capture and caused overall carbon dioxide emission more than the content of captured carbon dioxide in the product stream. Coal as fuel plays an important role in carbon emission reduction as one of the raw materials, along with the utility cost and the raw material cost in calcium looping section.