Yukishige Maezawa

Pre-Combustion CO2 Capture Using Ceramic Absorbent and Methane Steam Reforming

A novel CO2 separation technique that employs the chemical reaction of lithium-containing oxides with CO2 has been developed. Since this method is effective in the temperature range of 450oC to 700oC, it has the advantages of enabling CO2 separation in power plants without lowering the temperature and of absorbing CO2 from the steam-methane reforming process at the same time. Because the absorption is exothermic and the steam reforming is endothermic, the energy loss is expected to be significantly reduced by combining the reactions. Hydrogen yields are expected to be higher because the equilibrium may be shifted by the removal of the CO2 byproduct. We have therefore proposed a pre-combustion CO2 capture system using lithium silicate and steam reforming. Bench-scale experiments were performed to measure the methane conversion and CO2 removal efficiency in order to evaluate the feasibility of the pre-combustion CO2 capture system. At temperatures of less than 650oC, the methane conversion in the case of mixture of catalyst and absorbent was higher than that in the case of catalyst alone. In addition, the CO2 removal efficiency is almost 90%. These results appear to indicate that pre-combustion CO2 capture combined with steam reforming is feasible.