Simple and Carbon-Efficient Production of Synthetic Fuels by combining Biomass and Marine Energy

摘要

The UK's commitment to a large-scale reduction in CO_2 emissions will necessitate radical changes to the energy supply mix. In particular, replacing hydrocarbon-based transport fuels with carbon-neutral alternatives will require the use of renewable energy and renewable raw materials for the synthesis of fuels. However, the most valuable renewable energy in the UK is the wave, wind and tidal power resource that is located North and West of Scotland, while the electricity transmission grid is poorly developed in the contiguous onshore areas. One possibility for the transmission of such "stranded" energy to its point of use would be to use the power for the on-site production of synthetic, liquid carbonaceous fuels. In the work that we are presenting here, biomass is the CO_2-neutral carbon source for fuel products. Because biomass is deficient in hydrogen for the purpose of fuel synthesis, and because hydrogen can be produced from marine energies via water electrolysis, we propose processes to enhance both the ability of deriving liquid fuels from marine energy, and the ability to efficiently convert biomass to fuels. The avoidance of a shift step and of CO_2 elimination can contribute to more effective utilisation of the biomass, saving up to 0.78t CO_2 per ton of methanol produced. Further, the oxygen product from electrolysis further enhances the economics and energy efficiency of the process.