Solar gasification of coal using carbonate molten salt reactor

Abstract
The gasification of coal with CO₂ in the molten salt (K₂CO₃/Na₂CO₃) (CG-CO₂/molten salt system) has been studied at 1123K. The gasification rate of the cola into CO was enhanced in the molten salt by 3.3 times, compared with that without the molten salt. The reason for the enhancement was discussed. Main factor would be the enhancement of the coal charring owing to the efficient heat flow from the molten salt tot the coal through the solid/liquid interface between the coal surface and the molten salt. Another reason would be the catalytic effect of the alkaline cations (K⁺, Na⁺) on the Boudouard reaction (C + CO₂ = 2CO). This coal gasification process (CG-CO₂/molten salt) is an endothermic process (coal charring and Boudouard reactions), and can be applied for the solar thermochemical process to convert solar energy into chemical energy and store it. Since the CG-CO₂/molten salt system can be operated at 1123K, which is fairly lower than that for the conventional coal gasification with H₂O. We have proposed an solar hybrid fuel production system, where the solar energy and the coal energy can be hybridized using the CG-CO₂/molten salt system.