In contrast, H2
S absorption takes place more rapidly than CO2
absorption. Structured and random packing provide a lower residence time than trays, which allows more CO2
slippage to occur. Thus, for selective H2
S absorption, packing is often used in the absorption columns.
Some amine units experience fouling problems, which may be caused by corrosion products building up in the amine solvent or other contaminants entering with the feed gas or makeup solvent. Most units are designed with removal systems to filter out such contaminants. In some cases these systems may not be sufficient, and fouling of the mass transfer equipment may occur. This is a more significant problem for packed internals and particularly for the liquid distributors.
The first course of action should be to trace the origin of the contamination and eliminate it at its source or improve the removal systems. For packed towers, Koch-Glitsch can offer special distributor designs that use elevated distribution holes to provide improved resistance to fouling.