Reaction mechanism of coal gasification reforming by CaO with copper slag as heat carrier.

In this paper, copper slag is used as the heat carrier of coal gasification reaction, and CaO is used as the CO 2 adsorbent of syngas to solve the problem of high cost of heat source and high proportion of CO 2 produced by coal gasification. When copper slag is used as the heat carrier, the adsorption effect of CaO on CO 2 is most pronounced at temperatures of 600 °C and 700 °C, with CO 2 proportion reduced to 8% and H 2 proportion reaching 65%. Additionally, CaO exhibits a significant promotion effect on carbon conversion rate and gasification efficiency at temperatures above 800 °C, with the maximum carbon conversion rate reaching 89% and the highest gasification efficiency reaching 78%. At low temperatures, CaO primarily functions in gas phase reaction, such as WGS reactions, hydrocarbon reforming reactions, tar reforming reactions, and pyrolysis reactions. As the temperature increases, CaO primarily functions in gas-solid reactions such as oxidation reactions and secondary water gas reactions. In high-temperature environments, iron compounds present in copper slag undergo iron reduction reactions, while the Ca 2 Fe 2 O 5 compound formed from the reaction of CaO and Fe significantly promotes reforming reactions. • The copper slag is used as the heat carrier, and the waste heat in the copper slag is utilized. • CaO was selected as the adsorbent, and the synergistic effect with copper slag was found during adsorption. • The proportion of H 2 in syngas can be increased to 89 %. • The reaction mechanism of different temperature stages was analyzed. [ABSTRACT FROM AUTHOR]