Syngas production via high-temperature steam/CO_2 co-electrolysis: an economic assessment

摘要

Although it is not yet technologically mature, the high-temperature steam/CO_2 co-electrolysis process offers potentially a feasible and environmentally benign way to convert carbon-free or low-carbon electrical energy into chemical energy stored in syngas with a desired H_2 to CO ratio for further processing. An attractive application is to convert the as-produced syngas further into synthetic liquid fuels through the Fischer-Tropsch (F-T) process. The synfuel can be used as alternative fuels in the transportation sector while keeping the existing infrastructure and motor engine technology unchanged. The combination of the high-temperature steam/CO_2 co-electrolysis process and the F-T process thus offers an efficient way to store electricity in transportation fuels. The implementation of such a quasi carbon-neutral process depends on its economic competitiveness. In the present paper, an economic assessment of this process is performed through process modelling and sensitivity analysis. As an energy-intensive process, the availability of cost-effective electricity is crucial for its economic competitiveness. Preferred electricity sources are probably nuclear power and surplus wind power, with which synthetic fuels could be produced at a cost comparable to BTL (Biomass to Liquid) process. The present process is biomass-independent, and can also be located in regions where solar energy is abundant.