Thermodynamic analysis of a new process for hydrogen and electric power production by using carbonaceous fuels and high-temperature process heat

A new process for the simultaneous production of hydrogen and electrical power by using carbonaceous fuels and high-temperature process heat is presented in this paper. In an electrolytic cell, sulfur dioxide dissolved in an aqueous solution of sulfuric acid is electrochemically oxidized to sulfuric acid at the anode, while hydrogen gas is evolved at the cathode. The sulfuric acid produced in the cell provides the oxygen for the fuel combustion which subsequently takes place at high pressure. The combustion gas consisting mainly of CO₂, SO₂ and H₂O expands in a turbine in order to produce electrical power. After the expansion, the components sulfur dioxide and water are separated from the combustion gas and fed together with added water into the electrolysis cell.The process shows some advantages compared with already existing or proposed processes for the production of hydrogen or electric power. The influence of the sulfuric acid concentration and some other important process parameters on the energetic and exergetic efficiency of the total process is shown. The results shown in this paper have been obtained by using carbon (as a substitute for coal which is the preferred fuel) and a nuclear heat production plant (as an example of providing the required high-temperature process heat).