Co-production of hydrogen and electricity from lignocellulosic biomass: Process design and thermo-economic optimization

摘要

The thermochemical production of hydrogen from lignocellulosic biomass is systematically analyzed by developing thermo-environomic models combining thermodynamics with economic analysis, process integration techniques and optimization strategies for the conceptual process design. H_2 is produced by biomass gasification and subsequent gas treatment, followed by H_2 purification via CO_2 removal. It is shown how the overall efficiency is improved by considering process integration and computing the optimal integration of combined heat and power production. In the conversion process, electricity can be generated in steam and gas turbine cycles using the combustion of the off-gases and recovering available process heat. Additional electricity can be produced by burning part of the H_2-rich intermediate or of the purified H_2 product The trade-off between H_2 and electricity co-production and H_2 or electricity only generation is assessed with regard to energy, economic and environmental considerations. Based on multi-objective optimization, the most promising options for the polygeneration of hydrogen, power and heat are identified with regard to different process configurations. The best compromise between efficiency, H_2 and/or electricity production cost and CO_2 capture is identified. Biomass based H_2 and electricity reveal to be a competitive alternative in a future sustainable energy system.