Method and Device for the Absorption of Acid Gas From Natural Gas
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Abstract
A method and a device for the absorption of pressurised natural gas containing at least hydrogen sulphide and carbon dioxide, using a physically active absorption agent. The natural gas containing acid gas is first conveyed to an absorption column, where it is directly contacted with the physical detergent, and the physical detergent absorbs the acid gas, leaving only a residue. The charged detergent is conveyed to a stripping column, the working pressure being further reduced. The residue of the released acid gas from the detergent is desorbed in said stripping column. The detergent thus regenerated is returned, at least in part, to the absorption column. The acid gas leaving the first separator is conveyed to another absorption column, in which the part of the released acid gas containing predominately hydrogen sulphide is reabsorbed with regenerated detergent and mixed with the charged detergent from the first separator. The remaining acid gas not reabsorbed from the absorption column downstream of the first separator, is recovered as stripping gas. Said stripping gas is used in the stripping column for removing the hydrogen sulphide from the detergent supplied to the stripping column. The finely regenerated solvent is divided into two partial flows, one of which is conveyed to the absorption column downstream of the first separator stage while the other is conveyed to the absorption column in the flow of natural gas.
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Citations
22 Claims
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1-10. -10. (canceled)
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11. A process for the absorption of pressurized natural gas containing at least hydrogen sulphide and carbon dioxide, with the aid of physically acting absorbents, comprising
piping sour gas-bearing natural gas to an absorption column in which it comes into direct contact with a physically acting washing agent, the latter absorbing the sour gas and leaving a residual sour gas content only, feeding laden washing agent to a first separator, thereby reducing the working pressure and part of the solved sour gas being removed from the washing agent, at least a part stream of laden washing agent again undergoing a working pressure reduction and treatment in a stripping column where the residual content of solved sour gas is removed from the washing agent, returning at least part of thus regenerated washing agent to the absorption column, feeding sour gas leaving the first separator to a further absorption column in which regenerated washing agent is used to re-absorb a released sour gas portion that mainly contains hydrogen sulphide and that is added to laden washing agent in the first separator, the remaining sour gas portion not re-absorbed in the further absorption column arranged downstream of the first separator is recovered as stripping gas, said stripping gas is utilized in a stripping column for removing the hydrogen sulphide from the washing agent fed to the stripping column, and the intensely regenerated solvent is split up into two part streams, the first one being piped to the further absorption column arranged downstream of the first separator and the second one being fed to the absorption column arranged in the natural gas stream.
Specification