CO_2 Recovery from Diesel Engines in a Solar-Hydrogen-Methanol Energy System

Concept of solar-hydrogen-methanol energy system for the transportation sector in Japan is outlined. In the system, methanol is produced with CO2 recycled and H2 produced by electrolysis with photovoltaic power.Concerning CO2 recovery from the exhaust gas of a 10, 000 kW diesel engine to be used in the methanol energy system, the effects of CO2 recovery parameters such as gas and liquid flow rates, liquid concentration, and stripping temperature on the engine performance and the attainable CO2 recovery ratio are analyzed on the basis of a mass transfer calculation model for a packed column with aqueous monoethanolamine solution. Heat rejected from the engine is used for CO2 recovery, but reduction in the engine output power is not avoidable, which is mainly caused by the shortage in power of turbocharger and the supplemental supercharging power. Both the maximum attainable CO2 recovery ratio and the reduction in the engine output power depend on the ratio of the stripping steam feed rate to the flow rate of the exhaust gas.