Exergy analysis of a simulation of the sulfuric acid decomposition process of the SI cycle for nuclear hydrogen production

•Exergy analysis of sulfuric acid decomposition process is studied.•Effects of pressure and temperature on H2SO4 conversion are analyzed.•Exergy efficiency variation of H2SO4 decomposer is presented.•Operating conditions for high conversion and exergy efficiency are proposed.

This article details comprehensive energy and exergy analyses of the sulfuric acid decomposition process of the sulfur–iodine (SI) thermochemical cycle for hydrogen production. Energy and exergy efficiencies of the proposed process were evaluated over a variety of reaction temperatures and pressures. At an atmospheric temperature of 25 °C, the calculated values of exergy destruction of the H2SO4 decomposer ranged between 157 kJ/mol and 360 kJ/mol over reaction temperatures of 800–1000 °C and pressures between 1 and 50 atm. It was shown that the exergy efficiency of the H2SO4 decomposer improved with an increase in reaction temperature, while reaction pressure had a negative effect on exergy efficiency.