Hydrogen sulphide and mercaptans scavenging compositions
The present invention relates to a composition for scavenging hydrogen sulphide and/or mercaptans in hydrocarbon streams, the composition comprising an oxazolidine compound and a synergistic additive.
1. A composition for scavenging hydrogen sulphide and mercaptans from hydrocarbon streams, said composition comprising an oxazolidine compound and an additive selected from partial polyol esters comprising x ester units, y hydroxylated units and z ether units, x, y and z being integers such that x varies from 1 to 10, y varies from 1 to 10, and z varies from 0 to 50, wherein the weight ratio of oxazolidine compound(s) to said additive(s) ranges from 1 to 50, wherein the composition comprises from 19 to 99% wt of oxazolidine compound(s) and from 1 to 50% wt of said additive(s), based on the total weight of the composition,
wherein oxazolidine compound has a structure of formula (I):
wherein
n is an integer ranging from 1 to 6;
R1 and R2, identical or different, are selected from a hydrogen atom and a linear, branched or cyclic alkyl or alkenyl groups having from 1 to 6 carbon atoms, and wherein the polyols are chosen from the group comprising erythritol, xylitol, D-arabitol, L-arabitol, ribitol, sorbitol, malitol, isomalitol, lactitol, sorbitan, volemitol, mannitol, pentaerythritol, 2-hydroxymethyl-1,3-propanediol, 1,1,1-tri(hydroxymethyl) ethane, trimethylolpropane and carbohydrates.
2. The composition according to claim 1 , wherein the polyol is sorbitan.
3. The composition according to claim 1 , wherein the additive is selected from partial sorbitan ester of an unsaturated fatty acid comprising from 10 to 24 carbon atoms.
4. The composition according to claim 1 , further comprising a solvent.
5. The composition according to claim 1 , comprising:
From 19 to 80% wt of oxazolidine compound(s),
From 1 to 30% wt of said additive(s), and
From 1 to 80% wt of solvent(s),
based on the total weight of the composition.
6. Process for improving the efficiency of an oxazolidine compound for scavenging hydrogen sulphide and/or mercaptans in hydrocarbon streams, the process comprising a step of adding the additive defined in claim 1 in an oxazolidine compound to form a composition, wherein the weight ratio of oxazolidine compound(s) to said additive(s) ranges from 1 to 50, wherein the composition comprises from 19 to 99% wt of oxazolidine compound(s) and from 1 to 50% wt of said additive(s), based on the total weight of the composition.
7. Hydrocarbon stream comprising hydrocarbons and a composition according to claim 1 .
8. Hydrocarbon streams according to claim 7 , wherein the hydrocarbons are selected from crude oil, fuel oil, fuel, Light Petroleum Gas and natural gas.
9. A method for scavenging hydrogen sulphide and/or mercaptan in hydrocarbon streams, comprising contacting the hydrocarbon stream with the composition according to claim 1 .
10. The method according to claim 9 , wherein the weight ratio between hydrogen sulphide contained in the hydrocarbon stream before the step of contacting and the composition ranges from 1:2 to 1:0.05.
11. The composition according to claim 1 , wherein the polyols are carbohydrates selected from sucrose, fructose, maltose, glucose and saccharose.
12. The composition according to claim 1 , wherein the polyols are selected from sorbitan.
13. The composition according to claim 1 , wherein the additive is selected from sorbitan oleate optionally alkoxylated.
14. The composition according to claim 4 , wherein the solvent is present in an amount ranging from 1 to 80% wt, based on the total weight of the composition.
15. The composition according to claim 1 , comprising:
from 30 to 70% wt of bisoxazolidine compound(s),
from 1.5 to 20% wt of additive(s) selected from partial sorbitan ester of an unsaturated fatty acid comprising from 10 to 24 carbon atoms, and
from 15 to 65% wt of solvent(s),
based on the total weight of the composition.
16. The composition according to claim 15 , wherein the solvent is selected from poly alkyl ethers, aliphatic or aromatic solvents.
17. A method for scavenging hydrogen sulphide and/or mercaptan in hydrocarbon streams, comprising contacting the hydrocarbon stream with a composition, wherein the weight ratio between hydrogen sulphide contained in the hydrocarbon stream before the step of contacting and the composition ranges from 1:0.9 to 1:0.2,
the composition comprising an oxazolidine compound and an additive selected from partial polyol esters comprising x ester units, y hydroxylated units and z ether units, x, y and z being integers such that x varies from 1 to 10, y varies from 1 to 10, and z varies from 0 to 50, wherein the weight ratio of oxazolidine compound(s) to said additive(s) ranges from 1 to 50, wherein the composition comprises from 19 to 99% wt of oxazolidine compound(s) and from 1 to 50% wt of said additive(s), based on the total weight of the composition,
wherein the oxazolidine compound has a structure of formula (I):
wherein
n is an integer ranging from 1 to 6;
R1 and R2, identical or different, are selected from a hydrogen atom and a linear, branched or cyclic alkyl or alkenyl groups having from 1 to 6 carbon atoms, and wherein the polyols are chosen from the group comprising erythritol, xylitol, D-arabitol, L-arabitol, ribitol, sorbitol, malitol, isomalitol, lactitol, sorbitan, volemitol, mannitol, pentaerythritol, 2-hydroxymethyl-1,3-propanediol, 1,1,1-tri(hydroxymethyl) ethane, trimethylolpropane and carbohydrates.
18. The method according to claim 17 , wherein the weight ratio between hydrogen sulphide contained in the hydrocarbon stream before the step of contacting and the composition ranges from 1:0.7 to 1:0.3.