Natural or associated gas as well as refinery off gases may contain a number of acidic contaminants, primarily H2S and CO2, inert gases, helium and nitrogen and in rare cases Radon. Removal of these acidic components can be divided into two broad categories, chemical and physical. Sometimes a mixture of chemical and physical solvents are used either in a continuous or batch process.
The gas processing programme concentrates on treatment processes in the entire natural gas value chain, from discovery, exploration and transportation through to sales and marketing. The H2S can be converted to sulphur using a modified Claus Sulphur Recovery unit. Each of the various sulphur recovery processes is examined and their chemistry explored in detail. Other techniques that will be covered include Shell’s greener alternative Thiopaq.