CHARACTERISTICS AND CHEMICAL KINETICS OF HYDROGEN SULFIDE COMBUSTION IN THERMAL CLAUS REACTOR

Abstract

Hydrogen sulfide is a hazardous gas from both environmental safety and human health perspectives. Hydrogen sulfide presence in any combustion application results in the formation of acidic gases that affects ozone layer and causes acidic precipitation. Exposure to H2S levels at 100 ppm or higher can endanger human life. Hydrogen sulfide is commonly found to exist in crude natural gas and oil wells. With the decrease in fossil fuels reserves around the world, we will have to rely on extracting energy from wells that contain higher amounts of H2S. In addition, environmental regulations strictly regulate the H2S discharge into the atmosphere. Subsequently, efficient hydrogen sulfide treatment becomes of increasing importance with time.

Hydrogen sulfide treatment is typically a chemical reaction process (Claus process) in which hydrogen sulfide is combusted to end-products of sulfur and water. Hydrogen sulfide combustion in thermal Claus reactor has been investigated in this research. A reduced reaction mechanism for H2S oxidation has been developed using a novel error-propagation-based approach for reduction of detailed reaction mechanisms. The reduced mechanism has been used for detailed investigation of chemical kinetics mechanistic pathways in Claus process.

Experimental examination of H2S combustion in different flames, methane/air and hydrogen/air, is provided. Chemical kinetics pathways and reaction conditions responsible for sulfurous compounds formation (SO2, CS2, and COS) are addressed. Hydrogen sulfide flame emissions have been investigated for intermediate species identification using chemiluminescence flame spectroscopy. Effect of acid gas composition (H2S, CO2 and N2) on hydrogen sulfide combustion and Claus process efficiency is also provided. Finally, examination of the quality of captured sulfur with respect to reactor conditions is presented.