EP4656707A1

EP4656707A1 - Hydrogen sulphide and mercaptan scavenging composition comprising a particular triazine compound and a (poly)ethylene glycol

Info

Publication number: EP4656707A1
Application number: EP24305854.2A
Authority: EP
Inventors: Hemant Sunanda Surendra MONDKAR
Original assignee: TotalEnergies Onetech SAS
Current assignee: TotalEnergies Onetech SAS
Priority date: 2024-05-30
Filing date: 2024-05-30
Publication date: 2025-12-03

Abstract

The present invention relates to a composition useful for scavenging hydrogen sulphide and organic compounds comprising at least one sulfhydryl group, comprising a particular triazine compound and an additive chosen from (poly)ethylene glycols.

The invention also relates to the use of the composition of the invention for scavenging hydrogen sulphide and/or organic compounds comprising at least one sulfhydryl group in a liquid or gaseous stream.

Description

The present invention relates to a composition useful for scavenging hydrogen sulphide and organic compounds comprising at least one sulfhydryl group. Said composition comprises a particular triazine compound and an additive chosen from mono- and poly-ethylene glycols.
The present invention also relates to the use of such composition for scavenging hydrogen sulphide and/or organic compounds comprising at least one sulfhydryl group in a liquid or gaseous stream.
The invention also relates to the use of the (poly)ethylene glycol additive for improving the efficiency of triazine compounds in scavenging hydrogen sulphide and organic compounds comprising at least one sulfhydryl group in a liquid or gaseous stream.
The present invention also relates to a method for scavenging hydrogen sulphide and/or organic compounds comprising at least one sulfhydryl group comprising contacting a hydrocarbon stream such as crude oil, fuel or natural gas with the composition of the invention.
Hydrogen sulphide (H₂S) is a colourless and fairly toxic, flammable and corrosive gas which has a characteristic odour at a very low concentration. Hydrogen sulphide dissolves in liquid and gaseous streams such as hydrocarbon and water streams and can also be present in the vapour phase above liquid streams as well as in hydrocarbon gas such as LPG and natural gas. The hydrogen sulphide emissions can be harmful to workers operating in the drilling, production, transport, storage, and processing of such streams. It would therefore be desirable for the workers' comfort and safety to reduce or even eliminate the hydrogen sulphide emissions during the handling of said products.
Legislation has been in place for years, imposing strict regulations on hydrogen sulphide levels of hydrocarbon streams in pipelines, in storage and shipping containers.
Similar problems arise with organic compounds comprising a sulfhydryl group (-SH) such as mercaptans R-SH, thiocarboxylic acids RC(O)SH, dithiocarboxylic acids RC(S)SH, with R denoting a hydrocarbon chain. Such sulfhydryl-containing compounds are very corrosive, and are likely to release hydrogen sulphide.
A variety of chemical scavengers are available to reduce the concentration of hydrogen sulphide and sulfhydryl-containing compounds in liquid and gaseous streams containing them, in particular aqueous streams and hydrocarbon streams such as gas, crude oils and refined products. Some of the most common methods for treating hydrogen sulphide consist in contacting them with a chemical scavenger such as compounds containing a triazine group, glyoxal, as well as metal-based scavengers. Glyoxal has been used extensively as hydrogen sulphide scavenger but suffers from a major drawback since aqueous glyoxal solutions are highly corrosive and cannot be used for a gas tower application. Triazines have recently become more common chemical scavengers used for treating hydrogen sulphide from hydrocarbon streams.
Conventional triazine derivatives, in particular those bearing identical substituants on the three nitrogen ring atoms such as MEA-triazine, have different drawbacks. Therefore, new triazine-based hydrogen sulphide scavengers have been developed recently to overcome these drawbacks.
However, the use of these triazine compounds often requires an important contact time in order to be efficient in sulphur removal and thus involves injection of higher doses.
There remains a continuous need for novel solutions for eliminating hydrogen sulphide and other compounds comprising a sulfhydryl group in an efficient, economic and safe manner.
The Applicant has now discovered that the combination of a particular triazine compound with a specific additive chosen from mono- and poly-ethylene glycols was particularly efficient for scavenging hydrogen sulphide and unwanted organic compounds comprising at least one sulfhydryl group.
Therefore, the present invention relates to a composition useful for scavenging hydrogen sulphide and mercaptans in hydrocarbon streams, said composition comprising:

at least one compound of formula (I): wherein R is a radical selected from a linear, branched or cyclic hydrocarbyl group optionally comprising one or more heteroatoms, such as oxygen, sulfur, halogen, silicon, nitrogen atoms and R' represents H or CH₃, and
at least one (poly)ethylene glycol of formula (II): wherein n is an integer ranging from 1 to 30.

The composition of the present invention allows achieving an improved scavenging of hydrogen sulphide and organic compounds comprising at least one sulfhydryl group in a short contact time. The improvement can be seen when the remaining amount of sulphur compounds in the stream is reduced and/or when the speed of the scavenging of sulphur compounds is increased when contacting the composition according to the invention with said stream.
The composition of the present invention allows a faster and more efficient scavenging, i.e. the amount of sulphur compounds is decreased more rapidly and in a greater amount than with prior art scavenging compositions.
The present invention also relates to the use of such a composition for scavenging hydrogen sulphide and/or organic compounds comprising at least one sulfhydryl group in a liquid or gaseous stream.
The invention also relates to the use of a (poly)ethylene glycol of formula (II) as defined above for improving the efficiency of compounds of formula (I) in scavenging hydrogen sulphide and organic compounds comprising at least one sulfhydryl group in a liquid or gaseous stream.
The present invention also relates to a method for scavenging hydrogen sulphide and/or mercaptans comprising contacting a hydrocarbon stream such as crude oil, fuel or natural gas with the scavenging composition of the invention.
In the following, and at least one other indication, the limits of a value range are included within this range, particularly in the expressions "between" and "ranging from ... to ...".
Moreover, the expressions "at least one" and "at least" used in the present description are respectively equivalent to the expressions "one or more" and "more than or equal to".
Finally, in a manner known per se, C_N compound or group designates a compound or a group containing in its chemical structure N carbon atoms.
Within the meaning of the present invention:

the term "acyclic alkyl" refers to an alkyl group which does not form part of a cycle,
the term "acyclic alkenyl" refers to an alkenyl group which does not form part of a cycle,
the term "cyclic alkyl" refers to a saturated cycloalkyl group, wherein the cycle can be optionally substituted by one or more linear or branched alkyl or alkenyl groups. Preferably, the cycle comprises 5 or 6 carbon atoms and the substituent(s) if any comprise(s) from 1 to 6 carbon atoms, preferably from 1 to 3 carbon atoms,
the term "cyclic alkenyl" refers to an unsaturated cycloalkyl group, wherein the cycle comprising at least one unsaturation can be optionally substituted by one or more linear or branched alkyl or alkenyl groups. Preferably, the cycle comprises 5 or 6 carbon atoms and the substituent(s) if any comprise(s) from 1 to 6 carbon atoms, preferably from 1 to 3 carbon atoms.

Compound of formula (I)

The composition of the invention comprises at least one compound having the general formula (I): wherein:

R is a radical selected from a linear, branched or cyclic hydrocarbyl group optionally comprising one or more heteroatoms, such as oxygen, sulfur, halogen, silicon and nitrogen atoms and
R' represents H or CH₃.

According to a preferred embodiment, R' represents CH₃.
According to a preferred embodiment, R is different from -CHOH-CH₃.
According to a most preferred embodiment, R' represents CH₃ and R is different from -CHOH-CH₃.
Within the meaning of the present invention, a "hydrocarbyl group" is a linear, branched or cyclic group that can be aliphatic or aromatic and when it is a cyclic group, the cycle(s) can be substituted by linear or branched groups. The hydrocarbyl group comprises carbon atoms and hydrogen atoms and optionally heteroatoms selected from oxygen, sulfur, halogen, silicon, nitrogen, preferably selected from oxygen, sulfur, halogen, silicon.
According to an embodiment, R is selected from: R¹-OH, R¹-[O-R²]p-OH, optionally substituted benzyl, R¹-NR³R⁴, R⁵, R¹-[N(H)-R²]_n-NR³R⁴, R¹-[O-R²]_p-NR³R⁴, R¹-Q, R¹-[N(H)-R²]_n-Q, R¹-[O-R²]_p-Q, R¹-N(R³-Q)(R⁴-Q) wherein:

R¹ is selected from a linear, branched or cyclic alkyl or alkenyl radical having from 1 to 24 carbon atoms, preferably from 1 to 16 carbon atoms, more preferably from 1 to 12 carbon atoms, even more preferably from 1 to 8 carbon atoms or from an aromatic radical optionally substituted by one or more substituent selected from C₁-C₆-alkyl, hydroxyl, C₁-C₆-alkoxy, or C₁-C₆-alkylamine, preferably a phenyl radical substituted by C₁-C₆-alkyl;
R² is a linear, branched or cyclic alkyl or alkenyl radical having from 1 to 24 carbon atoms, preferably from 1 to 16 carbon atoms, more preferably from 1 to 12 carbon atoms, even more preferably from 1 to 8 carbon atoms;
R³ and R⁴ are, independently to each other, a hydrogen atom or a linear, branched or cyclic alkyl or alkenyl radical having from 1 to 16 carbon atoms, preferably from 1 to 12 carbon atoms, more preferably from 1 to 8 carbon atoms, even more preferably from 1 to 4 carbon atoms;
R⁵ is a linear, branched or cyclic alkyl or alkenyl radical having from 1 to 30 carbon atoms, preferably from 1 to 24 carbon atoms, more preferably from 1 to 16 carbon atoms, even more preferably from 1 to 12 carbon atoms;
Q is a radical selected from morpholine, piperidine, piperazine, or the monovalent radical of formula:
the optionally substituted benzyl can be a benzyl substituted by one or more substituent selected from C₁-C₆-alkyl, hydroxyl, C₁-C₆-alkoxy, C₁-C₆-alkylamine;
n is an integer ranging from 1 to 10, preferably from 1 to 6, more preferably from 1 to 4, even more preferably from 1 to 2;
p is an integer ranging from 1 to 10, preferably from 1 to 6, more preferably from 1 to 4, even more preferably from 1 to 2.

According to a preferred embodiment, R is selected from: R¹-OH, R¹-O-R²-OH, optionally substituted benzyl, R¹-NR³R⁴, R⁵, R¹-N(H)-R²-NR³R⁴, R¹-O-R²-O-R²-NR³R⁴, R¹-Q, R¹-N(H)-R²-Q, R¹-O-R²-O-R²-Q, R¹-N(R³-Q)₂ wherein:

R¹ is selected from a linear, branched or cyclic alkyl or alkenyl radical having from 1 to 24 carbon atoms, preferably from 1 to 16 carbon atoms, more preferably from 1 to 12 carbon atoms, even more preferably from 1 to 8 carbon atoms or from a phenyl radical substituted by C₁-C₆-alkyl;
R² is a linear, branched or cyclic alkyl or alkenyl radical having from 1 to 24 carbon atoms, preferably from 1 to 16 carbon atoms, more preferably from 1 to 12 carbon atoms, even more preferably from 1 to 8 carbon atoms;
R³ and R⁴ are, independently to each other, a hydrogen atom or a linear, branched or cyclic alkyl or alkenyl radical having from 1 to 16 carbon atoms, preferably from 1 to 12 carbon atoms, more preferably from 1 to 8 carbon atoms, even more preferably from 1 to 4 carbon atoms;
R⁵ is a linear, branched or cyclic alkyl or alkenyl radical having from 1 to 30 carbon atoms, preferably from 1 to 24 carbon atoms, more preferably from 1 to 16 carbon atoms, even more preferably from 1 to 12 carbon atoms;
Q is a morpholine radical or the monovalent radical of formula:
the optionally substituted benzyl can be a benzyl substituted by one or more substituent selected from C₁-C₆-alkyl, hydroxyl, C₁-C₆-alkoxy, C₁-C₆-alkylamine.

According to a more preferred embodiment, R is selected from: R¹-OH, R¹-O-R²-OH, benzyl, R¹-NR³R⁴, R⁵, R¹-N(H)-R²-NR³R⁴, R¹-O-R²-O-R²-NR³R⁴, R¹-Q, R¹-N(H)-R²-Q, R¹-O-R²-O-R²-Q, R¹-N(R³-Q)₂ wherein:

R¹ is selected from a linear or branched alkyl radical having from 1 to 16 carbon atoms, preferably from 1 to 12 carbon atoms, more preferably from 1 to 8 carbon atoms, even more preferably from 1 to 4 carbon atoms or from a phenyl radical substituted by C₁-C₆-alkyl;
R² is a linear or branched alkyl radical having from 1 to 16 carbon atoms, preferably from 1 to 12 carbon atoms, more preferably from 1 to 8 carbon atoms, even more preferably from 1 to 4 carbon atoms;
R³ and R⁴ are, independently to each other, a hydrogen atom or a linear or branched alkyl radical having from 1 to 16 carbon atoms, preferably from 1 to 12 carbon atoms, more preferably from 1 to 8 carbon atoms, even more preferably from 1 to 4 carbon atoms;
R⁵ is a linear or branched alkyl radical having from 1 to 24 carbon atoms, preferably from 1 to 16 carbon atoms, more preferably from 1 to 12 carbon atoms, even more preferably from 1 to 8 carbon atoms;
Q is a morpholine radical or the monovalent radical of formula:

Within the meaning of the present invention, an alkyl group is a saturated group consisting in carbon atoms and hydrogen atoms, that can be linear, branched or cyclic.
Within the meaning of the present invention, an alkenyl group is an unsaturated group consisting in carbon atoms and hydrogen atoms, that can be linear, branched or cyclic. The alkenyl group can be mono-unsaturated or poly-unsaturated.
According to a preferred embodiment, R³ is identical to R⁴.
According to a most preferred embodiment, the compound(s) of formula (I) is (are) chosen from the following compounds, and mixtures thereof:
Among the compounds disclosed above, preferred compound for use in the present invention are selected from compound I-A, compound I-B, compound I-C, compound I-D, compound I-E-, compound I-F, compound I-G, compound I-H, compound I-I, compound I-K, compound I-L, and mixture thereof. Compounds I-A, I-G, I-L and I-N are particularly preferred.
Preferably, the compound(s) of formula (I) is (are) present in an amount ranging from 50 to 99% by weight, preferably from 60 to 90% by weight, more preferably from 70 to 80% by weight, relative to the total weight of the composition.
In a preferred embodiment, the compound(s) selected from compound I-A, compound I-B, compound I-C, compound I-D, compound I-E-, compound I-F, compound I-G, compound I-H, compound I-I, compound I-K, compound I-L, and mixture thereof is (are) present in a total amount ranging from 50 to 99% by weight, preferably from 60 to 90% by weight, more preferably from 70 to 80% by weight, relative to the total weight of the composition.
In a more preferred embodiment, the compound(s) selected from compounds I-A, I-G, I-L and I-N is (are) present in a total amount ranging from 50 to 99% by weight, preferably from 60 to 90% by weight, more preferably from 70 to 80% by weight, relative to the total weight of the composition

(Poly)Ethylene glycols

The composition of the invention comprises at least one (poly)ethylene glycol chosen from compounds having the following formula (II): wherein n is an integer ranging from 1 to 30.
These compounds correspond to monoethylene glycol and polyethylene glycols containing up to 30 ethylene glycol units.
Preferably, n ranges from 2 to 20, more preferably from 3 to 12.
Preferably, the (poly)ethylene glycol(s) is (are) chosen from PEG-200 (compound of formula (II) with n=4), PEG-400 (compound of formula (II) with n=8), PEG-600 (compound of formula (II) with n=12) and mixtures thereof. PEG-600 is particularly preferred.
Preferably, said (poly)ethylene glycol(s) is (are) present in a total amount ranging from 0.1 to 30% by weight, preferably from 1 to 20% by weight, more preferably from 5 to 10% by weight, relative to the total weight of the composition.
In a preferred embodiment, the composition contains at least one compound chosen from PEG-200, PEG-400, PEG-600 and mixtures thereof in a total amount ranging from 0.1 to 30% by weight, preferably from 1 to 20% by weight, more preferably from 2 to 10% by weight, relative to the total weight of the composition.
In a more preferred embodiment, the composition contains PEG-600 in an amount ranging from 0.1 to 30% by weight, preferably from 1 to 20% by weight, more preferably from 2 to 10% by weight, relative to the total weight of the composition.
Preferably, the weight ratio between the total content of compound(s) of formula (I) and the total amount of (poly)ethylene glycol(s) of formula (II) is comprised between 1 and 40, preferably between 10 and 30.
According to an embodiment, the weight ratio between the total content of compound I-A, compound I-B, compound I-C, compound I-D, compound I-E-, compound I-F, compound I-G, compound I-H, compound I-I, compound I-K, compound I-L, and mixture thereof on one hand and the total amount of (poly)ethylene glycol(s) on the other hand is comprised between 1 and 40, preferably between 10 and 30.
According to another embodiment, the weight ratio between the total content of compound I-A, compound I-B, compound I-C, compound I-D, compound I-E-, compound I-F, compound I-G, compound I-H, compound I-I, compound I-K, compound I-L, and mixture thereof and the total content of compound(s) chosen from PEG-200, PEG-400, PEG-600 and mixtures thereof on the other hand is comprised between 1 and 40, preferably between 10 and 30.
According to another embodiment, the weight ratio between the total content of compound(s) I-A, I-G, I-L and I-N and mixtures thereof and the total content of PEG-600 is comprised between 1 and 40, preferably between 10 and 30.

Liquid solvents

According to a preferred embodiment, the composition of the invention further contains one or more liquid solvent(s).
By liquid, it is meant a solvent which is in liquid form at ambient temperature (20°C) and atmospheric pressure (1,013.10⁵ Pa).
According to a preferred embodiment, the solvent(s) is (are) selected from water and organic liquid solvents different from the (poly)ethylene glycols described above.
According to a preferred embodiment, the solvent(s) is (are) selected from organic liquid solvents different from said (poly)ethylene glycols.
Such solvents may in particular be chosen from poly oxyalkyl ethers, aliphatic hydrocarbons such as alkanes, aromatic solvents such as aromatic hydrocarbons and aromatic hetero-compounds, naphtas, and mixtures thereof.
Preferred organic solvents are chosen from aromatic solvents, such as N-methylpyrrolidone, xylene, toluene, benzene; and poly oxyalkyl ethers such as butyl carbitol (diethylene glycol monobutyl ether); as well as mixtures thereof.
Other preferred organic solvents include those derived from biomass, such as oils of vegetable origin. A particularly preferred solvent is cashew nutshell liquid, also known as CSNL, which is a widely available vegetable oil derived from cashew nut shell. CNSL can be used as a mixture with any other solvent such as those described herein.
The choice of the solvent mainly depends on the final use of the composition. When the composition is intended to be used for scavenging hydrogen sulphide and/or sulfhydryl-containing compounds in an aqueous stream, water may be a solvent of choice. When the composition is intended to be used for scavenging hydrogen sulphide and/or sulfhydryl-containing compounds in a hydrocarbon stream, an organic solvent will be preferred.
When the stream is a mixture of water and hydrocarbons (such as a mixture of crude oil and brine) a solvent having a dual solubility, i.e. a water solubility and a solubility in hydrocarbons, can be preferred. Poly alkyl ethers such as butyl carbitol are preferred solvents since they have such a dual solubility.
The composition of the invention advantageously contains an amount of solvent ranging from 5 to 50% by weight, preferably from 10 to 40%wt, more preferably from 20 to 30%wt, relative to the total weight of the composition.

Defoamer

The composition of the invention may further comprise art least one defoamer, preferably at least one silicone-based defoamer.
The defoamers are preferably chosen from polydimethylsiloxane polymers, more preferably from grafted polydimethylsiloxane polymers.
The composition of the invention advantageously contains an amount of defoamer ranging from 0.1 to 2% by weight, relative to the total weight of the composition.

Use

The present invention also encompasses the use of a composition as described above for scavenging hydrogen sulphide and/or organic compounds comprising at least one sulfhydryl group in a liquid or gaseous stream.
The organic compounds comprising at least one sulfhydryl group are especially chosen from mercaptans, thiocarboxylic acids and dithiocarboxylic acids.
The liquid or gaseous stream may be a monophasic stream such as in particular an aqueous stream or an organic stream, or a multiphasic stream containing both water and hydrocarbons (such as for instance oil/water or oil/water/gas or gas/water).
According to a preferred embodiment, the composition of the invention is used for scavenging hydrogen sulphide (H₂S) and mercaptans (compounds of formula RSH) in a hydrocarbon containing stream.
The mercaptans which are eliminated are typically those of formula RSH wherein R is an alkyl or alkenyl group containing from 1 to 8, preferably from 1 to 6 and more preferably from 1 to 4 carbon atoms.
The hydrocarbon containing streams are typically selected from crude petroleum oils, hydrocarbon fractions and residues deriving from the distillation thereof, light petroleum gas (LPG) and natural gas, as well as mixtures thereof with aqueous phases such as brine.
Such streams contain H₂S and/or mercaptans in total amounts which may range for example from 1 to 10 000 ppm by weight.
The present invention also concerns the use of (poly)ethylene glycol(s) of formula (II) as defined above for improving the efficiency of compound(s) of formula (I) for scavenging hydrogen sulphide (H₂S) and/or mercaptans in hydrocarbon streams.

Method

The present invention also relates to a method for scavenging hydrogen sulphide and/or organic compounds comprising at least one sulfhydryl group such as mercaptans in a liquid or gaseous stream comprising contacting said stream with the composition of the invention.
As described above, the liquid or gaseous stream may be monophasic such as in particular an aqueous stream or an organic stream, or multiphasic such as a stream containing both water and hydrocarbons (such as for instance oil/water or oil/water/gas or gas/water).
According to a preferred embodiment, the stream contains hydrocarbons. The stream may be especially selected from crude petroleum oils, hydrocarbon fractions and residues deriving from the distillation thereof such as in particular fuel oils and heavy fuel oils, light petroleum gas (LPG) and natural gas, as well as mixtures thereof with aqueous compositions such as brine.
The amount of composition used per amount of stream depends on the concentration of said compound(s) of formula (I) and of (poly)ethylene glycol(s) of formula (II) in the composition as well as the total content of hydrogen sulphide and/or organic compounds comprising at least one sulfhydryl group in the liquid or gaseous stream, as explained above.
The composition is contacted with the liquid or gaseous stream for a time sufficient to achieve an effective scavenging of hydrogen sulphide and of organic compounds comprising at least one sulfhydryl group.
The examples hereafter only aim at illustrating the present invention and shall not be interpreted so as to limit its scope.

Examples

Preparation of compositions

The following ingredients were used:

as compounds of formula (I): compounds I-A, I-G, I-L and I-N as disclosed above;
as polyethylene glycols having the following formula (II): PEG-200, PEG-400 and PEG-600;
as solvent: butyl carbitol

Compositions A1 to A24 (according to the invention) and C1 to C4 (comparative) were prepared by mixing the above ingredients in the amounts detailed Table (I) below:

Table (I)

	I-A	I-G	I-L	I-N	PEG-200		PEG-400		PEG-600		Solvent
A1	70	-	-	-	2.5	-	-	-	-	-	27.5
A2	70	-	-	-	-	5.0	-	-	-	-	25
A3	70	-	-	-	-	-	2.5	-	-	-	27.5
A4	70	-	-	-	-	-	-	5.0	-	-	25
A5	70	-	-	-	-	-	-	-	2.5	-	27.5
A6	70	-	-	-	-	-	-	-	-	5.0	25
A7	-	70	-	-	2.5	-	-	-	-	-	27.5
A8	-	70	-	-	-	5.0	-	-	-	-	25
A9	-	70	-	-	-	-	2.5	-	-	-	27.5
A10	-	70	-	-	-	-	-	5.0	-	-	25
A11	-	70	-	-	-	-	-	-	2.5	-	27.5
A12	-	70	-	-	-	-	-	-	-	5.0	25
A13	-	-	70	-	2.5	-	-	-	-	-	27.5
A14	-	-	70	-	-	5.0	-	-	-	-	25
A15	-	-	70	-	-	-	2.5	-	-	-	27.5
A16	-	-	70	-	-	-	-	5.0	-	-	25
A17	-	-	70	-	-	-	-	-	2.5	-	27.5
A18	-	-	70	-	-	-	-	-	-	5.0	25
A19	-	-	-	70	2.5	-	-	-	-	-	27.5
A20	-	-	-	70	-	5.0	-	-	-	-	25
A21	-	-	-	70	-	-	2.5	-	-	-	27.5
A22	-	-	-	70	-	-	-	5.0	-	-	25
A23	-	-	-	70	-	-	-	-	2.5	-	27.5
A24	-	-	-	70	-	-	-	-	-	5.0	25
C1	70	-	-	-	-	-	-	-	-	-	30
C2	-	70	-	-	-	-	-	-	-	-	30
C3	-	-	70	-	-	-	-	-	-	-	30
C4	-	-	-	70	-	-	-	-	-	-	30

Assessment of H₂S scavenging ability

The performance of each composition for scavenging H₂S was assessed by means of a H₂S scavenging test carried out following the protocol detailed below.
The test was carried out at room temperature. A 250 mL glass purger was charged with 100 mL of an inert solvent. A gas consisting of N₂ containing H₂S at a concentration of 50 ppm was released by a bubbling tube at a flow rate of 0.4 mL/min into the solvent contained in said purger. The solvent was continuously agitated by using a magnetic stirrer. The gas exiting the solvent and leaving the purger was conveyed to a H₂S detector.
At the beginning of each test, a setup was made as follows: the gas (H₂S in N₂ at a concentration of 50 ppm) was passed through the purger with a 0.4 mL/min flow rate, and the H₂S detector started recording the H₂S concentration at the outlet of the purger. Once the outlet H₂S concentration remained stable (with a value of 50 ppm constant reading at the detector), the scavenging composition (1ml of said composition is mixed with 2ml of butyl carbitol to ensure proper injection into the reactor) to be tested was quickly injected into the purger. As the scavenging composition starts reacting with H₂S which results in a reduction of the H₂S concentration at the outlet, as recorded by the detector. The H₂S concentration was recorded at every 5 sec time interval.
An interval of time of 30 min was respected between each test. In each test, once the H₂S scavenger has been injected into the purger, the concentration of H₂S recorded by the detector started decreasing from 50 ppm down towards 0 ppm, depending on the efficiency of the scavenging composition. The higher the H₂S scavenging efficiency of the composition, the faster the H₂S concentration recorded by the detector drops and the longer the rate of H₂S concentration recorded by the detector remains low. It was also observed that, once the scavenging composition was consumed, the concentration of H₂S recorded by the detector started increasing slowly back to 50 ppm.

Results

The results obtained are detailed in Table (II) below:

Table (II)

	Max scavenging obtained (in %)	Time required to obtain max scavenging (in sec)	Scavenging obtained at the end of test (1800 sec) (in %)
A1	72	95	52
A2	70	95	50
A3	74	90	55
A4	76	90	56
A5	75	90	58
A6	77	85	60
A7	78	100	50
A8	80	95	56
A9	73	90	55
A10	75	90	54
A11	74	95	57
A12	76	95	60
A13	81	100	54
A14	79	95	56
A15	78	95	60
A16	82	90	63
A17	79	85	58
A18	78	85	58
A19	82	90	57
A20	84	90	58
A21	82	85	56
A22	80	90	58
A23	80	80	60
A24	85	80	62
C1	54	130	28
C2	60	120	24
C3	56	120	27
C4	62	105	23

The above results show that compositions A1 to A24 according to the invention allow a faster and more efficient scavenging of hydrogen sulfide, than comparative compositions C1 to C4.

Claims

A composition comprising:
- least one compound of formula (I): wherein R is a radical selected from a linear, branched or cyclic hydrocarbyl group optionally comprising one or more heteroatoms, such as oxygen, sulfur, halogen, silicon, nitrogen atoms and R' represents H or CH₃, and

- at least (poly)ethylene glycol of formula (II): wherein n is an integer ranging from 1 to 30.
A composition as defined in claim 1 wherein R' represents CH₃.
A composition as defined in any preceding claim, wherein in formula (I) R is selected from: R¹-OH, R¹-[O-R²]p-OH, optionally substituted benzyl, R¹-NR³R⁴, R⁵,R¹-[N(H)-R²]_n-NR³R⁴, R¹-[O-R²]_p-NR³R⁴, R¹-Q, R¹-[N(H)-R²]_n-Q, R¹-[O-R²]_p-Q, R¹-N(R³-Q)(R⁴-Q) wherein:
- R¹ is selected from a linear, branched or cyclic alkyl or alkenyl radical having from 1 to 24 carbon atoms, preferably from 1 to 16 carbon atoms, more preferably from 1 to 12 carbon atoms, even more preferably from 1 to 8 carbon atoms or from an aromatic radical optionally substituted by one or more substituent selected from C₁-C₆-alkyl, hydroxyl, C₁-C₆-alkoxy, or C₁-C₆-alkylamine, preferably a phenyl radical substituted by C₁-C₆-alkyl;

- R² is a linear, branched or cyclic alkyl or alkenyl radical having from 1 to 24 carbon atoms, preferably from 1 to 16 carbon atoms, more preferably from 1 to 12 carbon atoms, even more preferably from 1 to 8 carbon atoms;

- R³ and R⁴ are, independently to each other, a hydrogen atom or a linear, branched or cyclic alkyl or alkenyl radical having from 1 to 16 carbon atoms, preferably from 1 to 12 carbon atoms, more preferably from 1 to 8 carbon atoms, even more preferably from 1 to 4 carbon atoms;

- R⁵ is a linear, branched or cyclic alkyl or alkenyl radical having from 1 to 30 carbon atoms, preferably from 1 to 24 carbon atoms, more preferably from 1 to 16 carbon atoms, even more preferably from 1 to 12 carbon atoms;

- Q is a radical selected from morpholine, piperidine, piperazine, or the monovalent radical of formula:

- the optionally substituted benzyl can be a benzyl substituted by one or more substituent selected from C₁-C₆-alkyl, hydroxyl, C₁-C₆-alkoxy, C₁-C₆-alkylamine;

- n is an integer ranging from 1 to 10, preferably from 1 to 6, more preferably from 1 to 4, even more preferably from 1 to 2;

- p is an integer ranging from 1 to 10, preferably from 1 to 6, more preferably from 1 to 4, even more preferably from 1 to 2.
A composition as defined in any preceding claim, wherein said compound of formula (I) is chosen from the following compounds, and mixtures thereof: preferably from compound I-A, compound I-B, compound I-C, compound I-D, compound I-E-, compound I-F, compound I-G, compound I-H, compound I-I, compound I-K, compound I-L, and mixture thereof; and more preferably from compounds I-A, I-G, I-L and I-N and mixtures thereof.
A composition as defined in any preceding claim, wherein the compound(s) of formula (I) is (are) present in an amount ranging from 50 to 99% by weight, preferably from 60 to 90% by weight, more preferably from 70 to 80% by weight, relative to the total weight of the composition.
A composition as defined in any preceding claim, wherein the (poly)ethylene glycols are chosen from compounds of formula (II) wherein n ranges from 2 to 20, preferably from 3 to 12.
A composition as defined in any preceding claim, wherein the (poly)ethylene glycols are chosen from PEG-200, PEG-400, PEG-600 and mixtures thereof, and preferably PEG-600.
A composition as defined in any preceding claim, wherein said (poly)ethylene glycol(s) is (are) present in a total amount ranging from 0.1 to 30% by weight, preferably from 1 to 20% by weight, more preferably from 2 to 10% by weight, relative to the total weight of the composition.
A composition as defined in any preceding claim, wherein the weight ratio between the total amount of compound(s) of formula (I) and the total amount of (poly)ethylene glycol(s) of formula (II) is comprised between 1 and 40, preferably between 10 and 30.
A composition as defined in any preceding claim further containing one or more liquid solvent(s).
A composition as defined in claim 10, wherein the solvent(s) is (are) chosen from water and organic solvents different from (poly)ethylene glycol compounds of formula (II), preferably from aromatic solvents, poly oxyalkyl ethers, naphtas and organic solvents derived from biomass; more preferably from aromatic solvents, such as N-methylpyrrolidone, xylene, toluene, benzene; poly oxyalkyl ethers such as butyl carbitol ; and mixtures thereof.
A composition as defined in anyone of claims 10 and 11, wherein the solvent(s) is (are) present in an amount ranging from 5 to 50% by weight, preferably from 10 to 40% by weight, more preferably from 20 to 30% by weight, relative to the total weight of the composition.
Use of a composition as defined in anyone of claims 1 to 12 for scavenging hydrogen sulphide and/or organic compounds comprising at least one sulfhydryl group such as mercaptans in a liquid or gaseous stream.
Use of at least one (poly)ethylene glycol of formula (II) as defined in anyone of claims 1, 6 and 7 for improving the efficiency of compound(s) of formula (I) in scavenging hydrogen sulphide (H₂S) and/or organic compounds comprising at least one sulfhydryl group such as mercaptans in a liquid or gaseous stream, preferably in a hydrocarbon stream.
Method for scavenging hydrogen sulphide and/or organic compounds comprising at least one sulfhydryl group such as mercaptans in a liquid or gaseous stream, comprising contacting said stream with a composition as defined in anyone of claims 1 to 12.