EFFECT OF ACID GAS (H2S AND CO2) ADDITION IN HYDROGEN/AIR FLAMES

Results on the effect of acid gas (H2S and CO2) addition in hydrogen/air flame are reported. Different equivalence ratios examined ranged from fuel-rich conditions (Phi=3.0), stoichiometric conditions (Phi=1.0), and fuel-lean conditions (Phi=0.5) to represent the range of conditions that may exist in actual operating Claus furnaces. Acid gas compositions examined are 100% H2S gas and 50% H2S/50% CO2 mixtures to represent a wide range of acid gas compositions encountered during processing of acid gases. Addition of 100% H2S gas in hydrogen/air flame degraded the rate of hydrogen oxidation. In addition, hydrogen sulfide combustion formed sulfur dioxide rather than more favorable elemental sulfur. On the other hand decomposition/production of H2S, SO2, and H-2 was observed to occur faster in 50% H2S/50% CO2 acid gas stream. Presence of carbon monoxide was a distinct mark on the release of oxygen from CO2 into the reaction pool. The presence of carbon monoxide also triggered the formation of other sulfurous-carbonaceous compounds, such as COS and CS2. The formation of these compounds adversely impacts the Claus process performance. The results provide conditions under which such compounds are formed and also reveal conditions to alleviate them.