Membrane-Assisted Catalytic Cracking of Hydrogen Sulphide (H2S)

Abstract

Hydrogen sulphide (H2S) has potentially high economic value if converted to sulphur and hydrogen. Various technical approaches to achieving this goal are reviewed. Thermal/catalytic decomposition of H2S to hydrogen and sulphur is a long-time candidate for an application of membrane reactor. Open reactor architecture (OA) is presented, where the coupling of reaction and hydrogen separation are achieved in the series of the consecutive conventional catalytic reactors (CRs), each followed by a membrane separator (MS). The number of the CR/MS units is determined by the required feed conversion. Such membrane-assisted reaction architecture simplifies the design, allowing the hydrogen separator made of silica membranes to perform at its optimal temperature of 600°C, while the catalytic H2S cracking proceeds in the CR at about 900°C. The theoretical calculations for one CR/MS/CR unit predicted an overall one-pass H2S conversion close to 40% at ambient pressure. It is proposed to supply the required process heat by inserting CR tubes inside the conventional Claus reactor where the unconverted H2S feed is disposed. This configuration radically improves the commercial outlook for H2S decomposition technology and allows hydrogen production without CO2 emissions.