Absorption of acid gases

Diglycolamine (DGA), is another amine solvent used in the Econamine process (Fig 1-2). Absorption of acid gases occurs in an absorber containing an aqueous solution of DGA, and the heated rich... 

This process selectively removes a certain gas from a gas mixture using a liquid absorbent. In the refining industry, this process is used extensively to free the product gas streams from acid gases (mainly H2S) either by using a physical or a chemical absorbent. Absorption of acid gases from natural gas are discussed in Chapter 1. 

Alkanolamines, generally referred to as amines, are organic compounds of the form Hn-N-(R0H)3-n (3) the hydroxyl group generally provides for the compounds solubility in water, while the HN group provides the alkalinity in water solutions to cause the absorption of acid gases. Amine processes used commercially are shown in Table I. These compounds are chemical solvents they combine chemically with H2S, C02, and other sulfur compounds. They are customarily regenerated by the application of heat. 

Use Intermediate, absorption of acidic gases, catalyst for polyurethane foams, pH control agent. 

Some secondary absorption of acid gases (particularly SO2) by the calcium hydroxide occurs en route to the bag filter, but the tertiary absorption on the filter medium is generally more significant. 

One proposed variation of the process incorporated simultaneous absorption of acid gases and liquefied petroleum gases (LPG) in the solvent, followed by separation of the absorbed components by fractional distillation. High percentage removal of both COS and mercaptans was also claimed. 

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