Catalytic H2S Conversion and SO2 Production over Iron Oxide and Iron Oxide/γ-Al2O3 in Liquid Sulfur

A stirred-glass autoclave containing liquid sulfur and solid iron oxide catalyst was used to study low-tonnage sulfur recovery from H2S-containing gas streams. The objectives were to test the feasibility of using both liquid sulfur as a reaction medium and iron oxide as a direct oxidation catalyst for prolonged H2S conversion. Using a 1.60% H2S and 0.80% O2 (balance N2) feed gas, fresh iron oxide acted primarily as a scavenger for bulk H2S removal from the inlet gas stream. Following the scavenging phase, the steady-state iron oxide/sulfide was able to maintain low catalytic activity (30% conversion). The steady-state catalyst did, however, have a strong ability to generate significant amounts of SO2 in the presence of inlet feed O2. Data showed that this SO2 production resulted from the oxidation of the liquid sulfur over the steady-state iron oxide/sulfide. The rate of SO2 formation was shown to be directly proportional to the concentration of O2 in the inlet feed gas. Although H2S conversions over stea...