Absorption operations organic chemical removal

Table 3.4 presents more specific heuristics for gas separations. The condensation of subcritical components at suitable pressure by cooling with water is often practical. Before applying low-temperature separations or membranes the removal of water by glycol absorption or by adsorption is compulsory. In the case of impurities accumulating in recycles a powerful method is their chemical conversion by selective catalysis. Before treatment the impurities should be concentered by an enrichment operation. Catalytic conversion is also recommended for handling volatile organic components (VOC). 

The Shell Sulfinol Process is used for removal of acidic constituents such as H2S, CO2, COS, etc. from a gas stream. Improved performance over other processes is due to the use of an organic solvent, Sulfolane (tetrahydrothiophene dioxide), mixed with an aqueous alkanolamine. Relative proportions of Sulfolane, alkanolamine, and water, as well as the operating conditions, are tailored for each specific application. Simultaneous physical and chemical absorption under feed gas conditions is provided by this Sulfinol solvent. Regeneration is accomplished by release of the acidic constituents at near atmospheric pressure and a somewhat elevated temperature. The flow scheme (Figure 4) is very similar to that of an aqueous alkanolamine system since it involves only absorption, regeneration and heat exchange under typical alkanolamine treater conditions. 

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