Process analysis of solar steam reforming of methane for producing low-carbon hydrogen

Regarding the trend of hydrogen-powered fuel cell engine development, hydrogen fuel is undisputedly the next generation renewable and sustainable energy carrier. The steam reforming of methane (SRM) is a field-proven technology for efficient hydrogen production. However, producing low-carbon hydrogen is the most technical challenge related to available hydrogen production technologies. This paper investigated the process analysis of SRM for low-carbon hydrogen production using concentrated solar energy as a heat source. Analysis of the solar SRM is carried out considering the reformate gas and their influencing factors. The operating temperature of 200-1000 °C and the pressure of 1.02-30 bar were considered when the mass ratio of steam-to-methane in feed gas was varied from 1.0 to 4.0. It was found that the composition of reformate gas, hydrogen yield, methane and steam conversion rate, the thermal efficiency of reforming reactor, and volume flow of reformate gas are significantly affected by the operating parameters including temperature, pressure, and the mass ratio of feed gas. Carbon content in the yield of hydrogen produced can be limited by considering the water-gas shift reaction in the SRM process. Besides, the centralized tower type solar concentrating system is selected as the heat source of the SRM process. The effect of solar radiation on the operation performance of the solar SRM process was analyzed. Direct normal irradiation is a key factor affecting the operating performance of the solar SRM process.