Hydrogenation of CaCO3 to CH4 catalyzed by NiCO3

Hydrogenation of calcium carbonate (CaCO 3 ) directly yields calcium oxide (CaO), carbon monoxide (CO) and methane (CH 4 ) with little dioxide ( CO 2 ) . It therefore is promising to retrofit the industries, such as the cement, refractory, calcium carbide and steel, that rely on CaCO 3 calcination for CaO but emit large amounts of CO 2 . To lower the hydrogenation temperature of CaCO 3 and to promote CH 4 production efficiency and selectivity this work investigates the catalytic effect of various nickel compounds on the CaCO 3 hydrogenation for CH 4 . Among the NiCO 3 , NiO, Ni 2 O 3 and Ni doped in CaCO 3 , NiCO 3 is the most active catalyst. It is hydrogenated to yield highly dispersed Ni in CaCO 3 at temperatures around 600 K, while the Ni catalyzes CaCO 3 hydrogenation for CH 4 at temperatures higher than 640 K, which are about 150 K lower than the non-catalytic CaCO 3 hydrogenation. The doping of 0.50% NiCO 3 converts 99.0% CaCO 3 to CH 4 . The catalytic CaCO 3 hydrogenation for CH 4 and CO can be modeled by the Shrinking core model (SCM) that shows activation energy ( E a ) of 110.0 kJ mol −1 for CH 4 production when 0.50% NiCO 3 is doped, which is lower than 211.9 kJ mol −1 for non-catalytic hydrogenation.