Energy efficiency of a hydrogen supply system using the reaction cycle of methylcyclohexane-toluene-hydrogen

Abstract

In this research, we investigated an energy supply system based on hydrogen derived from renewable energy. We modeled the energy flow and efficiency of a system using the MCH-toluene-hydrogen reaction cycle (MTHR) by methylcyclohexane (MCH, C6H11CH3) and toluene (C6H5CH3). Electric power storage by the MTHR and energy transport by a hydrogen infrastructure were investigated using numerical analysis. The energy flow of the whole system was investigated by cooperation of the numerical model of each component. The rate of input and output based on the calorific value of hydrogen defines the efficiency of each component and the system. When the electric power output of the renewable energy source was set to 100%, the maximum energy efficiency based on the calorific value of the hydrogen supplied from the hydrogenation facilities was 53.6%. Conversely, the electric power and thermal efficiency based on the rating of the dehydrogenation facilities were 29.9% and 6.8%, respectively. The maximum total power generation efficiency of the MCH-toluene-hydrogen reaction cycle was 16.0%; however, when thermal power was taken into account this rose to 16.7%. A case study was also conducted using a 1 MW wind farm combined with MTHR for Hokkaido in Japan.