Chemical process for sulfur reduction of hydrocarbons

Patent metadata

Field	Value
Publication number	US-10570344-B2
Application number	US-201715799704-A
Country	US
Kind code	B2
Filing date	Oct 31, 2017
Priority date	Apr 15, 2016
Publication date	Feb 25, 2020
Grant date	Feb 25, 2020

Abstract

Treatment of hydrocarbon streams, and in one non-limiting embodiment refinery distillates, with reducing agents, such as borohydride and salts thereof, alone or together with at least one co-solvent results in reduction of the sulfur compounds such as disulfides, mercaptans, thiophenes, and thioethers that are present to give easily removed sulfides. In one non-limiting embodiment, the treatment converts the original sulfur compounds into hydrogen sulfide or low molecular weight mercaptans that can be extracted from the distillate with caustic solutions, hydrogen sulfide or mercaptan scavengers, solid absorbents such as clay or activated carbon or liquid absorbents such as amine-aldehyde condensates and/or aqueous aldehydes.

First claim

What is claimed is:

1. A method for removing a sulfur compound from a hydrocarbon stream containing the sulfur compound, the method comprising:
contacting the hydrocarbon stream with an amount of a liquid, aqueous reducing agent effective to react with the sulfur compound to form at least one reaction product in a treated hydrocarbon stream;

where the aqueous reducing agent comprises:
from about 10 to about 80 vol % of at least one co-solvent based on the total amount of reducing agent, where the at least one co-solvent is a Lewis base co-solvent selected from the group consisting of ethers, dialkyl sulfides, amines, mono- and polyhydric alcohols, and mixtures thereof; and
at least one borohydride salt.

2. The method of claim 1 where the sulfur compound is selected from the group consisting of mercaptans having the formula R—S—H where R is a linear or branched C1 to C4 alkyl group, carbon disulfide (CS 2 ), carbonyl sulfide (COS), dialkyl sulfides having the formula R 1 —S—R 2 where R 1 and R 2 are independently linear or branched C1 to C4 alkyl groups, dialkyl disulfides having the formula R 1 —S—S—R 2 , unsubstituted and substituted thiophenes, and combinations thereof.

3. The method of claim 1 where the hydrocarbon stream comprises liquid or gas hydrocarbons selected from the group consisting of C1 to C12 alkanes, C2 to C12 alkenes, liquefied petroleum gas, natural gas, fuel gas, flare gas, naphtha, gasoline, kerosene, diesel fuel, and mixtures thereof.

4. The method of claim 1 where the co-solvent is selected from the group consisting of a mono- and polyhydric alcohols having from 1 to 8 carbon atoms.

5. The method of claim 1 where the borohydride salt is selected from the group consisting of:
inorganic borohydride salts having the formula M 1 BH 4 where M 1 is selected from the group consisting of Li, Na, and K or having the formula M 2 (BH 4 ) 2 where M 2 is selected from the group consisting of Mg, Ca, and Zn;
ammonium salts of borohydride having the formula R 3 4 N + BH 4 − , where R 3 are independently C1 to C4 or arylalkyl (benzyl), where the alkyl groups are C1 to C4; and
combinations thereof.

6. The method of claim 1 where in contacting the hydrocarbon stream with the reducing agent, the reducing agent is aqueous and has a pH ranging from about 7 to about 14.

7. The method of claim 2 where contacting the hydrocarbon stream with the reducing agent is conducted in the presence of a base selected from the group consisting of sodium hydroxide, potassium hydroxide, and combinations thereof.

8. The method of claim 1 where the effective amount of the reducing agent is up to two times the stoichiometric ratio of the reducing agent to the sulfur compound.

9. The method of claim 1 further comprising removing the at least one reaction product from the treated hydrocarbon stream, where removing the at least one reaction product from the hydrocarbon stream comprises a procedure selected from the group consisting of:
passing the treated hydrocarbon stream through a bed containing a solid absorbent selected from the group consisting of clay, carbon, a zeolite, and combinations thereof; and
washing the treated hydrocarbon stream with a liquid absorbent selected from the group consisting of amine-aldehyde condensates, aqueous aldehydes and combinations thereof.

10. The method of claim 1 where the co-solvent is present from about 20 to about 60 vol % of at least one co-solvent based on the total amount of reducing agent.

11. A method for removing a sulfur compound from a hydrocarbon stream containing the sulfur compound, the method comprising:
contacting the hydrocarbon stream with an amount of a reducing agent effective to react with the sulfur compound to form at least one reaction product in a treated hydrocarbon stream; and
removing the at least one reaction product from the treated hydrocarbon stream; where:

the reducing agent comprises:
from about 10 to about 80 vol % of at least one co-solvent based on the total amount of reducing agent; and
at least one inorganic borohydride salt;

the hydrocarbon stream comprises liquid or gas hydrocarbons selected from the group consisting of C1 to C12 alkanes, C2 to C12 alkenes, liquefied petroleum gas, natural gas, fuel gas, flare gas, naphtha, gasoline, kerosene, diesel fuel, and mixtures thereof; and
the sulfur compound is selected from the group consisting of mercaptans having the formula R—S—H where R is a linear or branched C1 to C4 alkyl group, carbon disulfide (CS 2 ), carbonyl sulfide (COS), dialkyl sulfides having the formula R 1 —S—R 2 where R 1 and R 2 are independently linear or branched C1 to C4 alkyl groups, dialkyl disulfides having the formula R 1 —S—S—R 2 , unsubstituted and substituted thiophenes, and combinations thereof; and
the at least one co-solvent is a Lewis base co-solvent selected from the group consisting of ethers, dialkyl sulfides, amines, mono- and polyhydric alcohols, and mixtures thereof.

12. The method of claim 11 where the co-solvent is selected from the group consisting of a mono- and polyhydric alcohols having from 1 to 8 carbon atoms.

13. The method of claim 11 where the borohydride salt is selected from the group consisting of:
at least one inorganic borohydride salts having the formula M 1 BH 4 where M 1 is selected from the group consisting of Li, Na, and K, or having the formula M 2 (BH 4 ) 2 where M 2 is selected from the group consisting of Mg, Ca, and Zn;
ammonium salts of borohydride having the formula R 3 4 N + BH 4 − , where R 3 are independently C1 to C4 or arylalkyl (benzyl), where the alkyl groups are C1 to C4; and
combinations thereof.

Assignees

• Baker Hughes A Ge Co Llc

Inventors

• Weers Jerry J
• O'Brien Timothy J
• Morgan Waynn C

Classifications

• C10L2230/04

  Catalyst added to fuel stream to improve a reaction · CPC title

• C10L2200/0415

  Light distillates, e.g. LPG, naphtha · CPC title

• C10G53/12

  including at least one alkaline treatment step · CPC title

• C10G21/20

  Nitrogen-containing compounds · CPC title

• C10G19/02

  with aqueous alkaline solutions · CPC title