Energy, exergy analysis in a hybrid power and hydrogen production system using biomass and organic Rankine cycle

Abstract

This study conducts a thorough analysis of an integrated system that has been specifically engineered to generate power and hydrogen concurrently by utilizing biomass and an Organic Rankine Cycle (ORC). Under its feed fluid heater and heat recovery exchanger, the ORC exhibits a dual-generation capability and is powered by biomass combustion. This research investigates a range of ORC configurations that utilize unique working fluids specifically designed for hydrogen production. A comprehensive thermodynamic model is applied to each fluid. An essential goal is to perform a parametric analysis, wherein the impact of critical parameters on the overall performance of the system is thoroughly examined. In addition, an innovative system comprising an integrated proton membrane exchange electrolyzer and biomass in ORC is presented in this study. An evaluation of the energy and exergy efficiencies of five distinct working fluids (R113, R114, R218, RC318, and R236fa) is conducted. The R113 working fluid exhibited the highest energy and exergy efficiencies, whereas the other fan working fluids were found to possess noteworthy characteristics. The R113 working fluid exhibits exergy and energy efficiencies of 67.15 % and 3.69 %, respectively. In addition, the study reveals valuable information regarding exergy losses in the electrolyzer and evaporator, emphasizing their impact on the generation of electricity. This study clarifies the correlation between fluctuations in temperature within the biomass fluid and the subsequent alterations in power and hydrogen generation, uncovering a compromise characterized by a reduction in energy and exergy efficiency. Furthermore, the research illustrates how escalating the mass flow rates of biomass fluids results in a decline in energy and exergy efficiency while concurrently generating power and hydrogen.