A review on solar reforming systems

Direct combustion of fossils is a low efficiency process that leads to excessive carbon dioxide emissions. Highly efficient and clean combustion processes can be achieved by the use of hydrogen as fuel. Hydrogen can be produced by steam reforming of methane which is a highly endothermic process. Heat required for such endothermic process can be achieved by the use of solar energy. The literature indicates that solar reforming is restricted to high temperature generating solar technologies like solar towers and dishes due to the high heat demand of the reforming process. A novel idea of using solar parabolic troughs in conjunction with a membrane reformer has been developed which allows low temperature operation of the process due to the equilibrium shift effect. Molten salt heated in the solar parabolic trough facility (up to ~600°C) provides heat needed for the endothermic reforming reactions. In this review, we provide critical assessment of the latest published developments in solar reforming technologies. We focus on reactor design concepts employed to couple the heat requirements of methane reforming process with concentrated solar power. The emphasis is novel, alternative routes which have potential of commercialization.