Multiscale techno-economic analysis of orange hydrogen synthesis

The conversion of hydrogen sulphide into value-added products, hydrogen and elemental sulphur, might be a promising route for the treatment of H2S waste streams and for a circular production of hydrogen. This work investigates the thermal splitting of H2S at different scales: the kinetic scale through dedicated experimental campaigns, the reactor scale with a combined experimental and modelling approach, and the process scale in a commercial simulation environment. The system was tested in a lab-scale reactor at 1 bar and in a temperature range going from 640 °C up to 1100 °C. H2S conversion was measured and used to validate a kinetic scheme implemented in a customized simulation suite. These results were then used for process design and scale-up in Aspen HYSYS, which, considering a feed of 10 t/h of pure H2S, estimated a production of 590.8 kg/h of hydrogen. An economic analysis was performed and the production cost of hydrogen resulted to be 2.23 $/kg.