A new-concept gas-solid combustion system “MERIT” for high combustion efficiency and low emissions

A new-concept gas-solid combustion system “MERIT” (Mediator Recirculation Integrating Technology) is proposed to contribute the settlement of environmental problems. This system divides combustion into two reactions, oxidation of metal by air at high temperature and reduction of metal oxide by fuel at low temperature. It recirculates the metal as an oxygen-carrier between these two processes. Since the low-temperature heat absorbed in the reduction reaction is released as the high-temperature heat in the oxidation reaction, the overall thermal efficiency is improved. There is no NO_x emission because the oxidation is a gas-solid reaction between metal and air without a flame. Since the reduction reaction produces only carbon dioxide and water vapor, CO₂ can be easily separated and collected by cooling the exhaust gas. The key point of the development of this combustion system is the kinetics of oxidation and reduction reactions. We carried out experiments to clarify the fundamental kinetics of the two reactions applying nickel as metal and methane as a fuel. It was certified that the rates of both reactions were fast enough. This result revealed that this combustion system has high potential to achieve high thermal efficiency and contribute to the settlement of environmental problems