Performance analysis of a mid- and low-temperature solar receiver/reactor for hydrogen production with methanol steam reforming

Abstract

Mid- and low-temperature solar thermochemical hydrogen production is considered as a promising field in the utilization of solar thermal applications. In this paper, a novel solar thermochemical receiver/reactor, which combines a tubular reactor and a parabolic trough collector (PTC) with the evacuated tubular receiver, was investigated. A non-isothermal model, based on a model of thermal energy loss from a PTC and a complex kinetic model of methanol steam reforming employing the Cu/ZnO/Al2O3 catalyst, was developed to analyze the performance of the mid- and low-temperature solar receiver/reactor for the new approach to solar hydrogen production. It is found that the catalytic bed temperature increased with the increment of the solar radiation. The factors influencing the hydrogen production, such as the feeding rates of the reactants, the solar radiation, the inlet temperature of the solar receiver/reactor, and the mole ratios of water to methanol, were investigated in detail. In the range of the solar radiation considered in this work, the solar thermochemical efficiency exceeds 50%, which is very competitive when compared with other high-temperature solar reactors. The inlet temperature of the solar receiver/reactor has a small impact on the hydrogen production for the whole solar reactor. At a mole ratio of water to methanol of 1, solar collector area of 600 m2 and a reactant feeding inlet-temperature of 423 K, the maximal hydrogen production capacity of the whole solar receiver/reactor can reach 54 kmol h−1 under the solar radiation intensity of 1000 W m−2. The encouraging results indicate a promising approach for the effective utilization of mid- and low-temperature solar thermal energy via the solar thermochemical process. Copyright © 2010 John Wiley & Sons, Ltd.