Process for removing mercaptans from a gas stream
AssigneeShell Oil Cpmpany
InventorsJozef Jacobus Titus Smits, Sipke Hidde Wadman
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Abstract
The present invention provides a process for removing mercaptans from a gas stream. In the process, a first mercaptan-comprising gas stream comprising at least a mercaptan of the general formula: R1—SH, wherein R1 is an alkyl group comprising 1 to 4 carbon atoms, and an acid component is contacted with an absorption medium to obtain a mercaptan-depleted gas stream. The absorption medium includes a substituted disulphide and a base. The substituted disulphide is of the general formula R2—SS—R3, wherein R2 and R3 are carbon comprising substituents of which the corresponding R2—SH and R3—SH thiols have a vapor pressure below the vapor pressure of any R1—SH thiol, and at least one of R2 and R3 is an electron withdrawing group.
Claims11
A process for removing mercaptans from a gas stream, comprising the steps:
- a) providing a gas stream comprising at least:
- a mercaptan of the general formula:
- R1—SH,
- wherein R1 is an alkyl group comprising 1 to 4 carbon atoms and
- an acid component, wherein the acid component is present in the gas stream in an amount in the range of from 0 to 20% by volume of the gas stream and
- b) contacting the gas stream with an absorption medium to obtain a mercaptan-depleted gas stream, wherein the absorption medium comprises:
- a substituted disulphide, wherein the substituted disulphide is of the general formula:
- R2—SS—R3,
- wherein R2 and R3 are carbon comprising substituents of which the corresponding R2—SH and R3—SH thiols have a vapour pressure below the vapour pressure of any R1—SH thiol and at least one of R2 and R3 is an electron withdrawing group;
- and
- a base, wherein the base is present in the absorption medium in an amount that exceeds the stoichiometric mol ratio at which the base will react with the acid component in the gas stream by at least a catalytic amount.
A substituted disulphide solution comprising:
- a) 1 to 10 mass % of a substituted disulphide of the general formula:
- R2—SS—R3,
- wherein R2 and R3 are carbon comprising substituents of which the corresponding R2—SH and R3—SH thiols have a vapour pressure below the vapour pressure of any butyl-SH thiol, and at least one of R2 and R3 is an electron withdrawing group, and
- b) a base;
- wherein the base is present in at least 3 mol % with regard to the amount of the substituted disulphide.
Dependencies are inferred from the claim text.