Co-methanation of CO and CO2 on the Composite Ni-La2O3-Ru Catalyst

Abstract

The catalytic co-methanation of CO and CO2 was studied with the objective of utilizing not only CO but also CO2 to synthesize a clean and highcalorific gaseous fuel, methane.Simultaneous methanation of CO and CO2 at low temperature was achieved by using the novel composite-catalyst such as 5%Ni-27%La2O3-0.6%Ru supported on the spherical silica support (0.3mm) having micro (5nm) and macro (600nm) bimodal pore structures. The reaction-gas mixture containing considerably high concentration of CO (0.06 atm) and CO2 (0.6 atm) with excess hydrogen (0.88 atm) was flowed at a space velocity of 11400 hr-1 in the temperature range from 170 to 290°C at atmospheric pressure. With the rise in reaction temperature, the reaction rate of CO2 increased acceleratedly of ter almost comlete consumption of CO, and total conversion of both CO and CO2 into methane with 100% selectivity and a high space time yield (61 mol/liter ·hr) were observed at 270°C.On the basis of kinetic data, the cause of the accelerating effect was determined that the concentration of surfece-carbon spices, which accompanies with CO methanation and has strong retardative action for the reaction, reduced in a marked degree at higher CO conversion, and released the retardation.