A new solar receiver/reactor structure for hydrogen production

Energy level matching of provided solar thermal energy with the involved reaction is important in determining the performances of a receiver/reactor. According to the main idea, i.e., minimizing irreversibility between the collected solar energy and the required reaction heat can increase the Solar-to-fuel energy conversion efficiency, in this study a new mid- and low-temperature solar receiver/reactor structure is proposed to match the concentrated solar energy level with the chemical reaction in a catalytic bed by changing the aperture width, diameter and length of the receiver/reactor tube along the flow direction. A multi-field coupling mathematical model that incorporates mass, fluid flow, energy conservation governing equations, and the kinetic model of the methanol steam reforming (MSR) is developed to investigate the performances of the new structure and the traditional structure. Results showed that the MCR increases by reducing the aperture width, meanwhile the maximum catalyst bed temperature (MCBT) can be reduced by 17.9 °C. The performance of the solar receiver/reactor can be further improved when the diameter and the aperture changes harmonious along the flow direction. The new structure exhibits 8.35-15.85% higher MCR than the traditional structure. As a result, a new insight is introduced for the design of the receiver/reactor structure.