Comparative analysis and multi-objective optimization of hydrogen liquefaction process using either organic Rankine or absorption power cycles driven by dual-source biomass fuel and geothermal energy

Abstract

The present work presents a novel approach of employing two renewable energy sources for power and liquefied hydrogen cogeneration. Meanwhile, the main scheme comprises a biomass-fed (municipal solid waste) Brayton cycle using a digester, a geothermal-based flash binary cycle, and a Claude cycle for hydrogen liquefaction; the heat recovery is also performed through either an organic Rankine cycle (case A) or a Kalina cycle (case B) joint to the main scheme having two different configurations. Regarding the waste-to-energy framework designed for high performance, the system is comprehensively studied and optimized from the energy, exergy, and economic aspects. In this regard, thermodynamic- and economic-based sensitivity analysis, net present value method, and multi-objective grey wolf optimization are implemented; the multi-criteria optimization is performed in three scenarios containing exergy efficiency-NPV, exergy efficiency-liquefied hydrogen's unit cost, and NPV-liquefied hydrogen cost. According to the results, the first scenario offers higher exergetic efficiency; the third scenario also provides a better hydrogen cost. As a result, the better optimum exergetic efficiency and liquefied hydrogen cost are equal to 10.95% and 3.84 $/kg for case A, and 10.38% and 3.74 $/kg for case B.