What are the two types of regenerators that are used in LNG plants, and what are their functions?

Two main types of regenerators are used in LNG plants: Amine Regenerators and Desiccant Regenerators. Amine regenerators, used in Amine Treating Units, remove acid gases (H2S and CO2) from natural gas. The function of the amine regenerator is to strip the absorbed acid gases from the rich amine solution. This is achieved by heating the rich amine, causing the acid gases to vaporize, thus regenerating the lean amine which is then recycled back to the absorber to repeat the acid gas removal process. Desiccant Regenerators (typically used with molecular sieves) remove water from the natural gas stream. The function of the desiccant regenerator is to remove the adsorbed water from the saturated desiccant material. This is done by heating the desiccant bed and purging it with dry gas, thus regenerating the desiccant which is then reused to remove moisture from the feed gas. Both types of regenerators are crucial for maintaining the purity of the natural gas stream and ensuring the efficient operation of the LNG plant. The specific design and operation of each type of regenerator depend on the type of absorbent (amine or desiccant) used and the specific contaminants being removed.