Solar thermal power cycle with integration of methanol decomposition and middle-temperature solar thermal energy

In this paper, we have proposed a new solar thermal power cycle which integrates methanol decomposition and middle-temperature solar thermal energy, and investigated its features based on the principle of the cascade utilization of chemical exergy. Also, the methanol decomposition with a catalyst was experimentally studied at temperatures of 150-300 °C and under atmospheric pressure. The chemical energy released by methanol fuel in this cycle consisted of two successive processes: solar energy drives the thermal decomposition of methanol in a solar receiver-reactor, and the syngas of resulting products is combusted with air, namely, indirect combustion after methanol decomposition. As a result, the net solar-to-electric efficiency of the proposed cycle could be 35% at the collector temperature of 220 °C and the turbine inlet temperature of 1300 °C, and the exergy loss in the indirect combustion of methanol was about 7% points lower than that in the direct combustion of methanol. The promising results obtained in this study indicated that this new solar thermal power cycle could make significant improvements both in the efficient use of the chemical energy of clean synthetic fuel and in the middle-temperature solar thermal energy in a power system.