Thermodynamic performance study of the CLHG/SOFC combined cycle system with CO2 recovery

Abstract

In this paper, the chemical looping hydrogen generation (CLHG) and solid oxide fuel cell (SOFC) are combined to achieve efficient power generation and CO2 separation and capture without energy consumption. The system can realize the utilization of H2 produced by CLHG in SOFC to avoid carbon deposition in it. The anode of the SOFC is completely refluxed into the steam reactor (SR) of CLHG without the need to install an afterburner, which avoids the direct combustion of fuel and greatly reduces the generation of NOx. High temperature air at SOFC cathode outlet and high temperature gas at fuel reactor (FR) outlet enter GT to do work. The transcritical carbon dioxide cycle (TRCC) is used to recover waste heat, making the system compact and efficient. The new CLHG/SOFC combined cycle system proposed in this paper has high performance, which can recover CO2 and prevent NOx generation, and also prevent carbon deposition in SOFC. In addition, the anode of SOFC is completely refluxed to SR to further improve the system performance. This paper discusses the effects of fuel flow, fuel utilization, SOFC operating temperature, system operating pressure, and CO2 turbine inlet pressure on system performance. The calculation results show that the total efficiency of the system can reach more than 80%, the power generation efficiency can reach more than 65%, and the exergy efficiency is more than 60%.