Composition and method for removal of carbonyl sulfide from acid gas containing same
View Patent ↗Novel solvent composition for selective removal of COS from a gas stream containing same, said composition comprising a) at least one polyalkylene glycol alkyl ether of the formula R 1 O-(Alk-O) n —R 2 (I) or 1,3-dimethyl-3,4,5,6-tetrahydro-2(1H)-pyrimidinone or a mixture of N-formylmorpholine and N-acetylmorpholine wherein R 1 is an alkyl group having from 1 to 6 carbon atoms; R 2 is hydrogen or an alkyl group having from 1 to 4 carbon atoms; Alk is an alkylene group, branched or unbranched, having from 2 to 4 carbon atoms, and n is from 1 to 10; and b) at least one alkanolamine compound of the formula R 3 NHR 4 OR 6 (II) or at least one piperazine compound of formula wherein R 3 is hydrogen, an alkyl group having from 1 to 6 carbon atoms, or the R 4 OH group; R 4 is a branched or unbranched alkylene group having from 1 to 6 carbon atoms; R 5 , independently in each occurrence, is hydrogen or an hydroxyalkyl group having from 1 to 4 carbon atoms; and R 6 is hydrogen, an alkyl group having from 1 to 6 carbon atoms or an hydroxyalkyl group having from 1 to 4 carbon atoms.
1. A solvent composition for selective removal of COS relative to CO 2 from a gas stream containing COS and CO 2 , said composition comprising
a) a mixture of N-formylmorpholine and N-acetylmorpholine; and
b) at least one alkanolamine compound of the formula
R 3 NHR 4 OR 6 (II)
or
at least one piperazine compound of formula
wherein R 3 is hydrogen, an alkyl group having from 1 to 6 carbon atoms, or the R 4 OH group; R 4 is a branched or unbranched alkylene group having from 1 to 6 carbon atoms; R 5 , independently in each occurrence, is hydrogen or an hydroxyalkyl group having from 1 to 4 carbon atoms; and R6 is hydrogen, an alkyl group having from 1 to 6 carbon atoms or an hydroxyalkyl group having from 1 to 4 carbon atoms, and
c) 9 percent by weight water or less.
2. The solvent composition according to claim 1 wherein the component b) is an alkanolamine of formula II in which substituent R 3 is hydrogen.
3. The solvent composition according to of claim 1 wherein the component b) is monoethanolamine.
4. The solvent composition according to claim 1 wherein the component b) is an alkanolamine of formula II in which substituent R 3 is an alkyl group having from 1 to 6 carbon atoms or the R 4 OH group.
5. The solvent composition according to claim 4 wherein the alkanolamine of formula II is selected from the group consisting of diethanolamine, methylethanolamine and diisopropanolamine.
6. The solvent composition according to claim 1 wherein the component b) is piperazine.
7. The solvent composition according to claim 1 wherein the component b) is hydroxyethylpiperazine.
8. A process for selective removal of COS relative to CO 2 from a gas stream containing COS and CO 2 with minimal removal of CO 2 from the gas stream, said process comprising treating the gas steam with a solvent composition comprising
a) a mixture of N-formylmorpholine and N-acetylmorpholine; and
b) at least one alkanolamine compound of the formula
R 3 NHR 4 OR 6 (II)
or
at least one piperazine compound of formula
wherein R 3 is hydrogen, an alkyl group having from 1 to 6 carbon atoms, or the R 4 OH group; R 4 is a branched or unbranched alkylene group having from 1 to 6 carbon atoms; R 5 , independently in each occurrence, is hydrogen or an hydroxyalkyl group having from 1 to 4 carbon atoms; and R 6 is hydrogen, an alkyl group having from 1 to 6 carbon atoms or an hydroxyalkyl group having from 1 to 4 carbon atoms, wherein removal of CO 2 from the gas stream due to the presence of component b) is less than 1 / 3 of the CO 2 present in the gas stream.
9. The process according to claim 8 for selective removal of COS from a gas stream, wherein R 3 is hydrogen.
10. The process according to claim 8 for selective removal of COS from a gas stream wherein the component b) is monoethanolamine.
11. The process according to claim 8 for selective removal of COS from a gas stream, wherein the component b) is an alkanolamine of formula II in which substituent R 3 is an alkyl group having from 1 to 6 carbon atoms or the R 4 OH group.
12. The process according to claim 11 for selective removal of COS from a gas stream wherein the alkanolamine of formula II is selected from the group consisting of diethanolamine, methylethanolamine, and diisopropanolamine.
13. The process according to claim 8 for selective removal of COS from a gas stream, wherein the component b) is piperazine.
14. The process according to claim 8 for selective removal of COS from a gas stream, wherein the component b) is hydroxyethylpiperazine.
15. A solvent composition for selective removal of COS relative to CO 2 from a gas stream containing COS and CO 2 , said composition comprising
a) a mixture of N-formylmorpholine and N-acetylmorpholine; and
b) at least one alkanolamine compound of the formula
R 3 NHR 4 OR 6 (II)
or
at least one piperazine compound of formula
wherein R 3 is hydrogen, an alkyl group having from 1 to 6 carbon atoms, or the R 4 OH group; R 4 is a branched or unbranched alkylene group having from 1 to 6 carbon atoms; R 5 , independently in each occurrence, is hydrogen or an hydroxyalkyl group having from 1 to 4 carbon atoms; and R6 is hydrogen, an alkyl group having from 1 to 6 carbon atoms or an hydroxyalkyl group having from 1 to 4 carbon atoms.