Proposing an innovative polygeneration process based on biogas fuel: A comprehensive thermo-enviro-economic (4E) analysis

Abstract

The utilization of biogas as a renewable fuel is feasible due to its high energy density, allowing for the development of polygonation structures in a cascade configuration. However, the high initial cost associated with biogas-based high-temperature applications is the central gap considered in this study. This paper introduces a novel heat integration model that employs a novel multi-stage cascade heat recovery and cost-effective operational approach. A biogas burner, an organic Rankine cycle, a Kalina cycle, an absorption chiller cycle, a heat supplier unit, and a proton exchange membrane electrolyzer-based hydrogen generating process are all part of the proposed system. Following the structure's modeling with the Aspen HYSYS program, thermodynamic, environmental, and economic evaluations are carried out along with a thorough parametric assessment. The simulation results indicate that the system has the capability to generate 2993 kW of electricity, 23350 kg/h of hot water at 80 °C, 68120 kg/h of chilled water at 10 °C, and generate 40.32 kg/h of hydrogen. This structure's energy, exergy, and electrical efficiencies are measured at 40 %, 23.71 %, and 16.68 %, respectively. Moreover, the exergy analysis indicated that the biogas burner and ORC evaporator account for 75.1 % of the total irreversibility (13800 kW).