Process for acid gas removal

Patent · Tue Jun 06 04:00:00 EDT 1978

OSTI ID:6268278

Butwell, K F

Union Carbide Corp.'s continuous process for the selective absorption of hydrogen sulfide from a feed gas containing H/sub 2/S and CO/sub 2/ countercurrently contacts the feed gas with an aqueous alkanolamine solution in an absorption zone having 2 to 10 separate stages. In each stage, the feed gas is contacted with lean aqueous alkanolamine solution (molality of 1.5 to 75 and a maximum loading of 0.1 mole of acid gas per mole of alkanolamine), and rich aqueous alkanolamine solution is withdrawn from the bottom of each stage. Every stage maximizes the equilibrium approach between the hydrogen sulfide in the gas and liquid phases while minimizing the equilibrium approach between the carbon dioxide in the gas and liquid phases. The rich solution loading in each stage is maintained within the range of about 0.1 to 0.3 mole of acid gas per mole of alkanolamine. Operated in combination with the absorption zone is a stripping zone that receives rich aqueous alkanolamine solution and generates lean solution. This multistage absorption process recovers, as a stripping-zone overhead, a gaseous product that has a combined molar ratio of carbon dioxide to hydrogen sulfide no greater than 6. The alkanolamine has the formula (R)/sub 3/N, where R is an alkanol radical of 2 to 3 carbon atoms and is unsubstituted or methyl-substituted, or an alkyl radical having 1 to 5 carbon atoms, provided that at least one R is an alkanol radical.

• Assignee: Union Carbide Corp.
• Patent Number(s): US 4093701
• OSTI ID: 6268278
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
AMINES
AQUEOUS SOLUTIONS
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON OXIDES
CHALCOGENIDES
DISPERSIONS
HYDROGEN COMPOUNDS
HYDROGEN SULFIDES
MIXTURES
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PURIFICATION
REMOVAL
SOLUTIONS
SULFIDES
SULFUR COMPOUNDS