Process for removing acidic gases from gaseous mixtures using aqueous scrubbing solutions containing heterocyclic nitrogen compounds
First Claim
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1. A process for removing acid gases selected from hydrogen sulfide and carbon dioxide from gaseous feeds which process comprises:
- contacting the feed with an aqueous scrubbing solution comprising water and 1 to 11 moles of a heterocyclic nitrogen compound per liter of solution which compound is selected from the group consisting of imidazole, a C1 -C3 alkyl-substituted imidazole where the alkyl groups are bonded to at least one carbon atom, and a C1 -C3 alkyl- or C1 -C3 hydroxyalkyl-substituted piperazine where the alkyl or hydrozyalkyl groups are bonded to both nitrogen atoms of the ring, the compound having a pKa no greater than about 8, at conditions whereby acid gases are absorbed by said scrubbing solution.
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Abstract
Disclosed is a process for removing acid gases from gaseous streams by contacting the stream with an aqueous scrubbing solution containing a heterocyclic nitrogen compound comprised of either a five-- or six--membered ring having a pKa no greater than about 8. Imidazole is a preferred heterocyclic nitrogen compound.
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Citations
18 Claims
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1. A process for removing acid gases selected from hydrogen sulfide and carbon dioxide from gaseous feeds which process comprises:
- contacting the feed with an aqueous scrubbing solution comprising water and 1 to 11 moles of a heterocyclic nitrogen compound per liter of solution which compound is selected from the group consisting of imidazole, a C1 -C3 alkyl-substituted imidazole where the alkyl groups are bonded to at least one carbon atom, and a C1 -C3 alkyl- or C1 -C3 hydroxyalkyl-substituted piperazine where the alkyl or hydrozyalkyl groups are bonded to both nitrogen atoms of the ring, the compound having a pKa no greater than about 8, at conditions whereby acid gases are absorbed by said scrubbing solution.
- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A process for removing carbon dioxide from a normally gaseous feed, which process comprises:
- contacting the feed with an aqueous scrubbing solution comprising water and 1-11 moles of one or more heterocyclic compounds per mole of solution which compounds are selected from imidazole, 4-methyl imidazole, and N,N-piperazine diethanol, at conditions whereby carbon dioxide is absorbed by the scrubbing solution.
- View Dependent Claims (11, 12, 13, 14, 15)
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16. A process for substantially completely removing carbon dioxide from a normally gaseous feed, which process comprises, in sequential steps:
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(a) contacting the feed with an aqueous scrubbing solution comprising water and imidazole wherein the total imidazole concentration in the solution is in the range from about 1 to about 11 moles per liter, said contacting being conducted at a temperature ranging from about 0°
to 100°
C. and at a pressure from about 200 to 1500 psia, thereby to absorb the carbon dioxide containing acidic gas in said scrubbing solution, and(b) regenerating said scrubbing solution at a temperature in the range from about 20°
to 200°
C. and at a pressure ranging from about 15 to 200 psia thereby to desorb the carbon dioxide containing acidic gas from the scrubbing solution. - View Dependent Claims (17, 18)
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Specification