Process development and simulation of a novel solar energy plant integrated with solid oxide fuel cell, hydrogen, heat recovery and carbon capture systems

Abstract

Solid oxide fuel cell (SOFC) releases significant high-temperature thermal energy during its operational mode. If this heat is not managed properly, it leads to thermal stresses, material shocks, and degradation. To effectively utilize such a high-temperature heat, this work presents a thermodynamic analysis and environmental assessment of a novel concept that synergistically integrates a benchmark SOFC with a four-step hybrid Cu-Cl thermochemical cycle. The developed system incorporates a SOFC unit for electricity generation, an afterburner for the complete oxidation of unreacted fuel (H₂, CO), a thermochemical cycle for utilizing high-temperature heat, a supporting Rankine Cycle (SRC), and an H₂ and CO₂ compression unit. The system is simulated by solving mass, energy, and exergy balances at steady-state conditions. Pinch point analysis is conducted using MATLAB to assess the thermodynamic feasibility of H₂ production. Furthermore, the specific primary energy consumption per unit of CO₂ avoided (SPECCA) is calculated to assess the system's environmental impacts. It is found that the CO₂ and H₂ compression train exhibit an overall exergy destruction of 5.83 kJ/mol of CO₂ and 5.98 kJ/mol of H₂ respectively. The thermolysis reactor of the Cu-Cl cycle carries the highest exergetic losses, with a share of 34.39%. The system exhibits a SPECCA value of 8.27 with 0.114 MJ/kg CO₂, considering the options with and without the Cu-Cl thermochemical cycle. The system's overall energy and exergy efficiencies are also 64.45% and 59.07% respectively.