Annual performance of a thermochemical solar syngas production plant based on non-stoichiometric CeO2

Abstract

We present, for the first time, a dynamic model of a 1-MWth thermochemical syngas production plant based on non-stoichiometric CeO2. This work aims to provide a simulation tool to assess plant performance under realistic solar conditions. We propose a route to produce a continuous syngas flow rate without requiring syngas storage, an optimisation method to achieve maximum solar-to-fuel efficiency, and a control strategy to maintain plant operation at optimal conditions. An extensive evaluation of the effect of dynamic and off-design performance on plant operation is also discussed for both discontinuous and continuous production of syngas. When a heat-recovery strategy is implemented, a maximum efficiency of 9.24–9.03% in Geraldton (WA) can be obtained, respectively. The thermochemical syngas production plant was also evaluated at another nine locations in Australia. The maximum solar-to-fuel efficiency of 9.68% was obtained in Alice Springs (NT), while in Melbourne (VIC) was 6.14%. These results demonstrate that previous steady-state calculations overestimated the values of the solar-to-fuel efficiency. This is due to an inability to accommodate the effect of essential variables such as: plant size and location, variation of the direct normal irradiance, heliostat field operation, and thermal inertia in solids, gases, reactors and storage tanks. Ultimately, this work demonstrates the need for the development of dynamic and off-design models to evaluate more accurately the potential of solar-driven fuel-production processes.