Hydrogen sulfide physical solvent processes

Still further process variations use physical absorption of hydrogen sulfide by the solvent, rather than chemical reaction with it, to effect the sweetening of natural gas. 

Most of the treating agents rely upon physical absorption and chemical reaction. When only CO2 is to be removed in large quantities, or when only partial removal is necessary, a hot carbonate solution or one of the physical solvents is the most economical selection. The sulfinol solvent (a mixture of an aqueous amine, chemical solvent, with sulfolane, physical solvent) is reported to be particularly advantageous (Taylor et al., 1991). Hydrogen sulfide may be removed solely by the use of several processes (Grosick and Kovacic, 1981 Mokhatab et al., 2006 Speight, 2007, 2008). 

The IFP process may be combined with a Claus unit in a variety of ways as shown in Tables 9-28 and 9-29. Since operation of the proce.ss is based on physical solubility (i.e., partial pressure) of hydrogen sulfide and sulfur dioxide in the solvent, the solvent flow rates and tower dimensions are essentially the same for a relatively wide range of hydrogen sulfide and sulfur dioxide concentrations in the feed gas. This enables the process to compensate for Claus plant upsets. 

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