The Development of a Continuously Stirred Process for the Removal of Hydrogen Sulfide from Natural Gas using Graphitic Catalysts

Natural gas is widely used for power generation. Its consumption is growing rapidly. The local consumption amounted to about 111.4 billion cubic meter in 2017. This consumption is projected to grow to 350 billion cubic meter by 2030. Most local natural gas reserves contain significant levels of hydrogen sulphide (H2S), requiring the removal of this toxic gas to below 4 ppm in order to meet the market specifications. Further reduction in the level of H2S in the treated natural gas to below the market specifications might be required for technical, environmental and safety reasons. Currently, the most widely utilized process for H2S removal from natural gas is amine absorption. However, this process is energy intensive, corrosive, and utilizes organic solvents, highlighting the urgent need for developing noncorrosive, organic solvent-free and less energy consuming technologies. Thus, the aim of this project is to develop (on a laboratory-scale) a more effective, organic solvent-free and noncorrosive process for H2S desulfurization. To achieve this aim, graphitic catalysts (i.e., metal oxides supported on graphene sheet) will be developed. The catalyst formulation will be tuned in order to optimize its effectiveness for the H2S desulfurization process at ambient conditions. The prepared graphitic catalysts will be characterized using different characterization techniques in order to get insights into the most influential characteristics of the prepared catalysts and, thus, manipulate their compositions to impart more improved catalytic performance. The performance of the synthesized graphitic catalysts will be probed by running H2S desulfurization tests using a continuously stirred process (CSP); the graphitic catalyst will be suspended in water through the continuous stirring. The hydrodynamic of the process will be optimized by manipulating the stirring (mixing) speed. Besides the effects of stirring speed, inlet gas flow rate and composition, the effects of the initial pH of the reaction medium as well as the catalyst loading on the rate and the extent of H2S desulfurization will be investigated. The coupling of graphitic catalyst with a CSP is still unaddressed in the published literature, to the best of the project teams knowledge.