Effect of Oxygen Injection on Hydrogen Sulfide Pyrolysis

Abstract

Pyrolysis of hydrogen sulfide, as an alternative treatment method to Claus process, with simultaneous hydrogen production and sulfur recovery is an energy intensive process. The high energy demand of the process remains a hindrance to its application. Production of hydrogen via hydrogen sulfide oxidation at very high equivalence ratios, compared to the high equivalence ratio of 3 employed in Claus reactor, has been studied experimentally. The objective of this approach is to alleviate the energy load requirement of hydrogen production from hydrogen sulfide stream. Since combustion of hydrogen sulfide cannot be sustained at such high equivalence ratios, partial oxidation reaction was examined in a heated quartz tubular reactor that was placed inside an electrical furnace. Oxygen concentration of 1% or 2 % in 10% H2S (called the 10%H2S/O2 mixture) were injected into the reactor with the remaining 90% nitrogen gas. These results were compared to the case of decomposing H2S alone. Experimental data showed that destruction of hydrogen sulfide increased with oxygen injection and that it increased with increase in oxygen concentration. Injection of oxygen at increased concentration consumed hydrogen constituent in hydrogen sulfide to water to result in dramatic decrease in hydrogen production. Formation of sulfur dioxide was absent over the examined temperature range of 1273–1673 K. These results provide the potential of hydrogen production from hydrogen sulfide oxidation, define the favorable operational conditions and outline the potential future developments for treatment of hydrogen sulfide.