HYDROGEN-PRODUCTION FROM HYDROGEN-SULFIDE BY THE FE-CL HYBRID PROCESS

The Fe-Cl hybrid process consisting of the absorption of H2S gas by FeCl3 aqueous solution and subsequent electrolysis of FeCl2 aqueous solution was proposed as a process for decomposing H2S to H2 and S. From the fundamental study, H2S absorption with almost 100% yield at 75-degrees-C and satisfactorily low electrolysis voltage (0.7 V) at a current density of 100 mA cm-2 at 70-degrees-C were obtained. In the chemical engineering study for process development, a bubble-column H2S absorber with a rotating-cup type gas feeder and a bipolar type electrolysis cell (5 or 20 cells with an electrode area of 432 cm2) were developed. A bench-scale plant for the whole Fe-Cl hybrid process with a production capacity of 2.1 N m3 of H2 day-1 and 3 kg of S day-1 was constructed, and intermittent operation of the plant was successfully performed for 1000 h.