Hydrogen sulphide and mercaptan scavenging composition comprising an oxazolidine compound

Abstract

The present invention relates to a formulated composition, in particular useful for scavenging hydrogen sulphide and mercaptans in hydrocarbon streams, said composition comprising at least one oxazolidine compound and at least one organic solvent, preferably aromatic solvent, especially Heavy Aromatic Naphta (HAN) solvent. The invention also relates to the use of an organic solvent, preferably an organic hydrocarbon solvent, in particular an aromatic solvent, preferably HAN, for improving the efficiency of oxazolidine compound(s) in scavenging hydrogen sulphide and organic compounds comprising at least one sulfhydryl group contained in a liquid or gaseous stream, preferably in a hydrocarbon gas stream.

Description

[0001] The present invention relates to a formulated composition useful for scavenging hydrogen sulphide and organic compounds comprising at least one sulfhydryl group, said formulated composition comprises an oxazolidine compound and an aromatic solvent.

[0002] The present invention also relates to the use of an organic solvent, preferably an organic hydrocarbon solvent, in particular an aromatic solvent, preferably Heavy Aromatic Naphta (HAN), for improving the efficiency of oxazolidine compound(s) in scavenging hydrogen sulphide and organic compounds comprising at least one sulfhydryl group contained in a liquid or gaseous stream, preferably in a hydrocarbon gas stream, especially in a sour gas stream for natural gas production.

[0003] The present invention also relates to a method for scavenging hydrogen sulphide and / or organic compounds comprising at least one sulfhydryl group in a liquid or gaseous stream, preferably in a hydrocarbon gas stream, comprising contacting said stream with the formulated composition according to the invention. Preferably, the formulated composition according to the invention is used for treating a hydrocarbon gas stream, for example a sour gas stream for natural gas production, and the method according to the invention comprises injecting said formulated composition into the gas stream to be treated.

[0004] Hydrogen sulphide (H 2 S) 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 is therefore desirable for the workers' comfort and safety to reduce or even eliminate the hydrogen sulphide emissions during the handling of said products.

[0005] Legislation has been in place for years, imposing strict regulations on hydrogen sulphide levels of hydrocarbon streams in pipelines, in storage and shipping containers.

[0006] 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.

[0007] 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.

[0008] Other hydrogen sulphide scavengers have been developed, and among them scavengers based on oxazolidine, like 3,3'-methylenebis(5-methyloxazolidine), known as MBO. A method for scavenging hydrogen sulphide from sour hydrocarbon substrates has been described in WO 98 / 02501.

[0009] However, this technology requires an important contact time in order to be efficient in sulphur removal and thus involves injection of higher doses.

[0010] Formulations of MBO with promoters, also named boosters, have been developed to enhance the efficiency of MBO. For example, WO 2017 / 102693 describes a composition comprising MBO and one or more additive selected among urea, urea derivatives, amino acids, guanidine, guanidine derivatives or 1,2-diols.

[0011] Other promoters, such as polyethylene glycol-based promoters, have been described. While enhancing the H 2 S scavenging performance of MBO, these compounds have a major drawback as they present a high viscosity and are solid at room temperature. Therefore, the compositions containing MBO combined with such promoters can hardly be used at cold temperatures nor be injected using high pressure systems due to their viscosity.

[0012] There remains a continuous need for novel solutions for improving elimination of hydrogen sulphide and other compounds comprising a sulfhydryl group in an efficient, economic and safe manner.

[0013] The Applicant has now discovered that the formulated oxazolidine compounds in an organic solvent, preferably in an organic hydrocarbon solvent, more preferably in an aromatic solvent, preferably a Heavy Aromatic Naphta (HAN) solvent, was particularly efficient for scavenging hydrogen sulphide and unwanted organic compounds comprising at least one sulfhydryl group, and in particular enables to improve the scavenging performance of the pure oxazolidine compound.

[0014] Therefore, the present text discloses a formulated composition useful for scavenging hydrogen sulphide and mercaptans in hydrocarbon streams, said composition comprising at least one oxazolidine compound and at least organic hydrocarbon solvent, in particular an aromatic solvent, preferably HAN solvent having a kinematic viscosity, measured at 40°C according to ASTM D445 standard, of less than 14 mm 2< / s, preferably between 1 and 10 mm 2< / s.

[0015] According to one of its aspects, the present invention as claimed thus relates to a formulated composition, preferably useful for scavenging hydrogen sulphide and mercaptans in hydrocarbon streams, said formulated composition comprising at least one oxazolidine compound and at least one organic hydrocarbon solvent, preferably at least one aromatic solvent, especially HAN solvent, in a weight ratio oxazolidine compound(s) / aromatic solvent(s) ranging from 40 / 60 to 95 / 5, preferably from 50 / 50 to 90 / 10, preferably from 55 / 45 to 80 / 20, especially from 60 / 40 to 70 / 30,said composition having a kinematic viscosity, measured at 40°C according to ASTM D445 standard, of less than 14 mm 2< / s, preferably between 1 and 10 mm 2< / s.

[0016] 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 inventors have surprisingly found that formulating the oxazolidine compound in an organic hydrocarbon solvent, in particular in an aromatic solvent, especially HAN solvent, enables to improve scavenging of hydrogen sulphide and organic compounds comprising at least one sulfhydryl group, compared to a composition of 100% of said oxazolidine compound (in other words, compared to a non-formulated form also called the concentrated or pure oxazolidine compound).

[0017] The improvement of scavenging hydrogen sulphide and organic compounds comprising at least one sulfhydryl group comprised in a stream 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 compared with the values obtained by using the oxazolidine compounds alone.

[0018] Advantageously, the amount of sulphur compounds in the stream is reduced by at least 10%, preferably by at least 15%, more preferably between 20 to 50%, more preferably between 20 to 40%, compared with the value obtained by using the oxazolidine compounds alone (non-formulated form).

[0019] The reduction of the amount of sulphur compounds in the stream is particularly improved when the composition according to the invention is injected in the stream where the stream is in gas phase, especially for a hydrocarbon gas stream.

[0020] The present invention also relates to the use of the formulated composition of the invention for scavenging hydrogen sulphide and / or organic compounds comprising at least one sulfhydryl group in a liquid or gaseous stream, preferably in a gaseous stream. In a particular embodiment, the formulated composition of the invention is used in the treatment of a hydrocarbon gas stream, for example of a sour gas stream for natural gas production.

[0021] Preferably, the reduction of the amount of sulphur compounds in the gas stream is particularly improved when the formulated composition according to the invention is injected downstream the high-pressure separator enabling the sulphur compounds removal in the gas treatment unit of an oil production device.

[0022] The formulated composition of the present invention allows a faster scavenging, i.e. the amount of sulphur compounds is decreased more rapidly than with a composition comprising 100% of the oxazolidine compound(s).

[0023] Thus, surprisingly, even with a lower active content of oxazolidine compound, the formulated form makes it possible to achieve similar or even improved scavenging performance in comparison with the pure oxazolidine compound. Advantageously, the use of a formulated form of the oxazolidine compound to achieve similar or even better scavenging efficiency than the non-formulated form, makes it possible to lower the active content of oxazolidine compound that is required for treating said stream, especially said hydrocarbon gas stream. As the oxazolidine compound is formulated, toxicity is advantageously lowered as the diluted form is no more toxic by contact with skin.

[0024] The invention also relates to the use of an organic solvent, preferably an organic hydrocarbon solvent, in particular an aromatic solvent, preferably HAN, for improving the efficiency of oxazolidine compound(s) in scavenging hydrogen sulphide and organic compounds comprising at least one sulfhydryl group contained in a liquid or gaseous stream, preferably in a hydrocarbon stream such as crude oil, fuel or natural gas.

[0025] Preferably, the invention relates to the use of an organic solvent, preferably an organic hydrocarbon solvent, in particular an aromatic solvent, preferably HAN, for improving the efficiency of oxazolidine compound(s) in scavenging hydrogen sulphide and organic compounds comprising at least one sulfhydryl group contained in an hydrocarbon gas stream, for example in a sour gas stream for natural gas production, by formulating said oxazolidine compound(s) with said solvent, preferably HAN, and injecting the formulated form into the gas stream to be treated.

[0026] The present invention also relates to a method for improving the efficiency of oxazolidine compound(s) in scavenging hydrogen sulphide and organic compounds comprising at least one sulfhydryl group, the method comprising the step of formulating the oxazolidine compound(s) with an organic solvent, preferably an organic hydrocarbon solvent, in particular an aromatic solvent, preferably HAN, preferably HAN.

[0027] The present invention also relates to a method for improving the efficiency of oxazolidine compound(s) in scavenging hydrogen sulphide and organic compounds comprising at least one sulfhydryl group, in an hydrocarbon gas stream, for example in a sour gas stream for natural gas production, the method comprising the step of formulating the oxazolidine compound(s) with an organic solvent, preferably an organic hydrocarbon solvent, in particular an aromatic solvent, preferably HAN, preferably HAN, and injecting the formulated form into the gas stream to be treated.

[0028] The present invention also relates to the use of a formulated form of at least one oxazolidine compound in at least one organic solvent, preferably organic hydrocarbon solvent, more preferably aromatic solvent, preferably HAN, especially in a weight ratio oxazolidine compound(s) / aromatic solvent(s) ranging from 40 / 60 to 95 / 5, in particular 50 / 50 to 90 / 10 and more particularly 55 / 45 to 80 / 20, especially 60 / 40 to 70 / 30, for improving scavenging of hydrogen sulphide and organic compounds comprising at least one sulfhydryl group in a liquid or gaseous stream, in particular in a hydrocarbon stream such as crude oil, fuel or natural gas, preferably in an hydrocarbon gas stream, for example in a sour gas stream for natural gas production, in comparison with the concentrated oxazolidine compound (formulation of 100 wt% of said oxazolidine compounds). The kinematic viscosity of the formulated form, measured at 40°C according to ASTM D445 standard, is of less than 14 mm 2< / s, preferably between 1 and 10 mm 2< / s.

[0029] 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, in particular in a hydrocarbon stream, such as crude oil, fuel or natural gas, comprising contacting said stream with a formulated composition of the invention.

[0030] In particular, the present invention relates to a method for scavenging hydrogen sulphide and / or mercaptans in a hydrocarbon gas stream, for example in a sour gas stream for natural gas production, comprising injecting in said gas stream a formulated composition of the invention.

[0031] 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 ...".

[0032] 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".

[0033] 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.

[0034] 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. Oxazolidine compounds

[0035] The composition of the invention comprises at least one oxazolidine compound.

[0036] Within the meaning of the present invention, the expression "oxazolidine compound" refers to a compound comprising at least one oxazolidine cycle, said cycle being substituted or not substituted.

[0037] Preferably, the oxazolidine compound(s) is (are) selected from compounds comprising one oxazolidine cycle (i.e. mono-oxazolidines) or two oxazolidine cycles (i.e. bisoxazolidines).

[0038] Oxazolidine compounds useful in the present invention and comprising one oxazolidine cycle preferably correspond to the following formula (I): wherein R1 and R2, identical or different, are selected from a hydrogen atom and linear or branched, cyclic or acyclic, alkyl or alkenyl groups having from 1 to 6 carbon atoms, preferably from a hydrogen atom, a methyl and an ethyl group, and

[0039] R3 is selected from a hydrogen atom and linear or branched, cyclic or acyclic, saturated or unsaturated, aromatic or non aromatic hydrocarbon groups having from 1 to 30 carbon atoms, preferably from a hydrogen atom and from linear or branched, cyclic or acyclic, saturated or unsaturated, aromatic or non aromatic hydrocarbon groups having from 1 to 20 carbon atoms.

[0040] Preferably, R1 and R2, identical or different, are selected from a hydrogen atom and a methyl group.

[0041] According to a first preferred embodiment, R1 and R2 are identical and represent a hydrogen atom and R3 represents a hydrogen atom.

[0042] According to a second preferred embodiment, R1 represents a methyl group, R2 represents a hydrogen atom, and R3 represents a hydrogen atom.

[0043] According to a third preferred embodiment, R1 and R2 are identical and represent a hydrogen atom, and R3 is selected from linear or branched, cyclic or acyclic, saturated or unsaturated, aromatic or non aromatic hydrocarbon groups having from 1 to 20 carbon atoms.

[0044] Preferred mono-oxazolidine compounds are 1,3-oxazolidine, 5-methyloxazolidine, and 3-(C1-C20)alkyl-oxazolidines, which correspond to the following formulae: 1,3-Oxazolidine 5-Methyloxazolidine 3-(C1-C20)Alkyl-Oxazolidines R=C1-C20

[0045] Oxazolidine compounds useful in the present invention and comprising two oxazolidine cycles preferably correspond to the following formula (II): wherein: r is an integer ranging from 1 to 6, preferably from 1 to 2; Q 1< and Q 2< , identical or different, are selected from a hydrogen atom and linear or branched, cyclic or acyclic, alkyl or alkenyl groups having from 1 to 6 carbon atoms, preferably from 1 to 2 carbon atoms.

[0046] Preferably, r denotes 1.

[0047] Preferred bisoxazolidine compounds are 3,3'-methylenebis(oxazolidine) and 3,3'-methylenebis(5-methyloxazolidine) (also known as MBO), which correspond to the following formulae: 3,3'-Methylenebis(oxazolidine) 3,3'-Methylenebis(5-methyloxazolidine) (MBO)

[0048] Preferably, the oxazolidine compound(s) is (are) selected from 1,3-oxazolidine, 5-methyloxazolidine, 3-(C1-C20)alkyl-oxazolidines, 3,3'-methylenebis(oxazolidine), 3,3'-methylenebis(5-methyloxazolidine) (MBO) and mixtures thereof.

[0049] The oxazolidine compound(s) is (are) present in an amount preferably ranging from 40 to 95 wt%, preferably from 50 to 90 wt%, preferably from 55 to 80 wt%, preferably from 60 to 70 wt%, relative to the total weight of the composition.

[0050] In a particular embodiment, the oxazolidine compound(s) chosen from mono-oxazolidines, bisoxazolidines and mixtures thereof are present in an amount ranging from 40 to 95 wt%, preferably from 50 to 90 wt%, preferably from 55 to 80 wt%, preferably from 60 to 70 wt%,, relative to the total weight of the composition.

[0051] In another particular embodiment, the oxazolidine compound(s) chosen from 1,3-oxazolidine, 5-methyloxazolidine, 3-(C1-C20)alkyl-oxazolidines, 3,3'-methylenebis(oxazolidine), 3,3'-methylenebis(5-methyloxazolidine) (MBO) and mixtures thereof are present in an amount ranging from 40 to 95%wt, preferably from 45 to 90%wt, more preferably from 50 to 80%wt, even more preferably from 60 to 70%wt, relative to the total weight of the composition.

[0052] Preferably, the oxazolidine compound is 3,3'-methylenebis(5-methyloxazolidine) (MBO) and is present in an amount ranging from 40 to 95 wt%, preferably from 50 to 90 wt%, preferably from 55 to 80 wt%, preferably from 60 to 70 wt%,, relative to the total weight of the composition.Aromatic solvent

[0053] As mentioned above, the invention is based on the formulation of said oxazolidine compound(s) in an organic solvent, preferably in an organic hydrocarbon solvent, preferably in an aromatic solvent, especially in a HAN solvent.

[0054] Of course, the organic solvent is chosen such that it does not affect the integrity of the oxazolidine compound(s). In particular, the organic solvent is chosen in order to obtain a stable solution under a wide range of temperatures, especially ranging from -10°C to 60°C.

[0055] Preferably, the organic solvent is aromatic solvent.

[0056] Preferably, the aromatic solvent is Heavy aromatic Naphta (or HAN).

[0057] HAN is a mixture of hydrocarbons obtained by the distillation of aromatic fraction. HAN consists predominantly of, preferably consists of, aromatic hydrocarbons having a carbon number between 9 and 16, preferably between 9 and 11, and having a boiling point, measured at atmospheric pressure (1,013.10 5< Pa), comprised between 165°C and 290°C, preferably between 181 and 205°C. HAN is a liquid solvent.

[0058] In particular, the organic solvent, preferably organic hydrocarbon solvent, more preferably aromatic solvent, preferably HAN, is used in a weight ratio oxazolidine compound(s) / solvent(s) ranging from 40 / 60 to 95 / 5, in particular 50 / 50 to 90 / 10 and more particularly 55 / 45 to 80 / 20, especially 60 / 40 to 70 / 30.

[0059] The formulated composition of the invention preferably comprises an amount of aromatic solvent(s), preferably HAN, in a weight ratio oxazolidine compound(s) / aromatic solvent(s) ranging from 40 / 60 to 95 / 5, in particular 50 / 50 to 90 / 10 and more particularly 55 / 45 to 80 / 20, especially 60 / 40 to 70 / 30, relative to the total weight of the composition.

[0060] In one embodiment, the formulated composition of the present invention consists of the oxazolidine compound(s), for example NMO, and aromatic solvent(s), in particular HAN.

[0061] In a particular embodiment, the formulated composition of the invention is a formulation of oxazolidine compound(s), for example NMO, and organic solvent, preferably organic hydrocarbon solvent, preferably aromatic solvent(s), preferably HAN, in weight ratio oxazolidine compound(s) / aromatic solvent(s) ranging from ranging from 40 / 60 to 95 / 5, in particular 50 / 50 to 90 / 10 and more particularly 55 / 45 to 80 / 20, especially 60 / 40 to 70 / 30.Additive enhancing the activity of the oxazolidines compounds

[0062] In another embodiment, the formulated composition according to the invention can further comprise from 0.1 to 30 wt%, preferably from 0.1 to 20 wt%, preferably from 0.5 to 15 wt%, more preferably from 1 to 10 wt%, based on the total weight of the composition, of one or more additive(s) enhancing the activity of the oxazolidine compounds(s), also known as booster(s).

[0063] In particular, the weight ratio between the content of oxazolidine compound(s) and said booster(s) can range from 1 to 100, preferably from 1 to 50, more preferably from 2 to 30, even preferably from 2 to 10.

[0064] The additive enhancing the activity of the oxazolidine compound can be chosen among: a compound comprising at least one reaction product of a poly(C2-20-carboxylic acid) having at least one tertiary amino group with secondary amines, such as disclosed in WO2020115135. For example, the polycarboxylic acid contains at least 3, more preferably 3 to 12, and even more preferably 3 to 5, carboxyl groups. For example, the secondary amines are of the formula HNR 2 , wherein R radicals are independently straight-chain aliphatic radicals, preferably alkyl radicals having from 10 to 30 carbon atoms, preferably from 14 to 24 carbon atoms. Preferably, the additive may be a mixture of 2,2',2",2'''-(ethylenedinitrilotetrakis-N,N-di(C16)alkylacetamide and 2,2',2",2‴-(ethylenedinitrilotetrakis-N,N-di(C18)alkylacetamide, for example available from BASF under the commercial names Keroflux ®< 3614 and Kerflux ®< 3241; a modified or non-modified alkylphenol-aldehyde condensation resin.

[0065] Preferably, the resin is bio-based.

[0066] The resin may be for example a non-modified alkylphenol-aldehyde condensation resin, obtainable by condensation of: at least one phenol substituted by a hydrocarbon group having from 12 to 24 carbon atoms, with at least one aldehyde having from 1 to 8 carbon atoms.

[0067] Preferably, the resin is based on bio-based phenol, for example on cardanol. Cardanol can be obtained in a known manner from an oil that is itself obtained from the shell of cashew kernels also known as cashew nutshell liquid.

[0068] For example, said resin can be cardanol-formaldehyde resin.

[0069] The resin may also be a resin obtainable by condensation of: at least one 4-(2-alkoxyethyl)phenol compound having the following formula (I): wherein X denotes: a linear or branched, saturated or unsaturated, hydrocarbon group containing from 1 to 24 carbon atoms, optionally interrupted with one or more heteroatoms, especially one or more heteroatoms chosen among oxygen, nitrogen, sulfur and / or phosphorous atoms, a saturated or unsaturated, aromatic or non-aromatic, heterocyclic or cyclic moiety, with at least one aldehyde having from 1 to 8 carbon atoms, preferably from 1 to 4 carbon atoms

[0070] Preferably, the resin is based on bio-based phenol, especially on a renewable compound, namely on Tyrosol which is a natural occurring nontoxic phenol.

[0071] For example, said resin can be a 4-(2-alkoxyethyl)phenol - formaldehyde resin (also named O-alkylated tyrosol formaldehyde resin).

[0072] In another variation, the resin may be a modified alkylphenol-aldehyde condensation resin that is obtainable by a Mannich reaction of an alkylphenol-aldehyde condensation resin with: at least one aldehyde and / or one ketone having 1 to 8 carbon atoms; and at least one hydrocarbon compound having at least one alkylmonoamine or alkylpolyamine group having from 2 to 30 carbon atoms, optionally with at least one alkylene oxide; said alkylphenol-aldehyde condensation resin being obtainable by condensation of at least one alkylphenol substituted by at least one linear or branched alkyl group having 1 to 30 carbon atoms and at least one aldehyde and / or one ketone having 1 to 8 carbon atoms, such as disclosed in WO2020115134.

[0073] According to a particularly preferred embodiment, the modified alkylphenol-aldehyde resin is obtainable by a Mannich reaction of an alkylphenol-aldehyde condensation resin with formaldehyde and at least one alkylpolyamine having at least two primary amine groups and comprising a fatty chain having from 12 to 22 carbon atoms; said alkylphenol-aldehyde condensation resin being itself obtainable by condensation of para-nonylphenol and formaldehyde. 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, such as disclosed in WO2020115133.

[0074] According to a particularly preferred embodiment, the polyol ester is chosen from partial sorbitan esters of an unsaturated fatty acid comprising from 10 to 24 carbon atoms, preferably from sorbitan oleate optionally alkoxylated, such as the product available from Oleon under the name Radiasurf ®< , for example Radiasurf ®< 7348. a reaction product of a compound (A) with a compound (B), optionally followed by a quaternization reaction of the reaction product of (A) and (B) with a compound (C), wherein: compound (A) is a hydrocarbyl-substituted acylating agent, compound (B) is a nitrogen-containing compound selected from primary, secondary or tertiary polyamines and a compound comprising at least one tertiary amine group and at least one group selected from the primary and secondary amines or the alcohols, compound (C) is a quaternizing agent, such as disclosed in WO2020115132.

[0075] For example, said additive can be the reaction product of a polyisobutenyl succinic anhydride (PIBSA) with a nitrogen-containing compound formula (II):         H 2 N-[(CHR 3< -(CH 2 ) p -CHR 4< ) q -NH] m -H wherein: R3 and R4, which are identical or different, represent hydrogen or an alkyl or alkenyl group comprising from 1 to 4 carbon atoms, q is an integer varying from 1 to 3, m is an integer varying from 1 to 10 and p is an integer equal to 0 or 1, or the reaction product of a polyisobutenyl succinic anhydride with an alkanolamine comprising one hydroxyl function, one primary amine function and one tertiary amine function and from 4 to 16 carbon atoms, followed by a quaternization reaction a quaternizing agent. an (ethoxylated) phenol compound of formula R-Ph-(OCH 2 CH 2 ) n -OH wherein Ph denotes a benzene ring, R represents a linear or branched saturated or unsaturated hydrocarbon chain comprising from 8 to 24, preferably from 10 to 22, preferably from 12 to 14, carbon atoms, which may be substituted or not substituted, and n represents a number ranging from 0 to 20. For example, preferred compounds are (poly) ethoxylated cardanols chosen from cardanols ethoxylated with n EO wherein n is as defined above, hereafter denoted "cardanols n EO". In a usual manner, "cardanol n EO" denotes a compound consisting of cardanol ethoxylated with an average number of n moles of oxyethylene per mole of cardanol. Particularly preferred compounds are cardanol 1 EO, cardanol 2.5 EO, cardanol 5 EO, cardanol 7 EO, cardanol 12 EO, and mixtures thereof. a quaternary ammonium salt chosen form compounds of formula wherein: R 1< and R 2< , identical or different, represent a linear or branched, alkyl group having from 1 to 4 carbon atoms; R 3< represents a linear or branched, saturated or unsaturated, aromatic or non-aromatic, hydrocarbon group comprising from 8 to 30 carbon atoms and optionally or more heteroatoms chosen from oxygen and nitrogen; R 4< represents a hydrogen atom or a linear or branched, saturated or unsaturated, aromatic or non-aromatic, hydrocarbon group comprising from 1 to 30 carbon atoms, and X -< is an organic or inorganic anion.

[0076] For example, R 1< and R 2< are both methyl group, R 3< represents a linear or branched alkyl group comprising from 8 to 20 and preferably from 12 to 18 carbon atoms or a phenyl group optionally substituted with an amino group of formula NR'R" wherein R' and R", identical or different, represent alkyl groups containing from 1 to 4 carbon atoms, preferably 1 or 2 carbon atoms, R 4< represents H, an alkyl group containing from 1 to 4 carbon atoms or an aromatic group such as in particular an alkyl-phenyl group, X -< is a halide ion, preferably a chloride ion. For example, the additive may be chosen from dodecyltrimethylammonium chloride, N,N,N',N'-Tetramethyl-p-phenylenediamine dihydrochloride, Di(hydrogenated tallow)dimethylammonium chloride, Tallowtrimethylammonium chloride, Benzyldimethyldodecylammonium chloride, Benzyldimethylhexadecylammonium chloride, and mixture thereof; an alkanolamine, such as disclosed in WO202212286, of formula: wherein n is an integer ranging from 1 to 6; R1 is a divalent linear or branched, cyclic, acyclic, alkyl or alkenyl group having from 1 to 12 carbon atoms; R2 and R3, identical or different, are selected from H, a linear or branched, cyclic or acyclic, alkyl or alkenyl group having from 1 to 12 carbon atoms or -(R4-O)m-H wherein each m is independently an integer ranging from 1 to 6 and R4 is a divalent linear or branched, acyclic or cyclic, alkyl or alkenyl group having from 1 to 12 carbon atoms.

[0077] For example, the alkanolamine may be selected from methyldiethanolamine, monoisopropanolamine, polyethanolamine, monoethanolamine, diethanolamine, methylmonoethanolamine, dimethylethanolamine, diethylethanolamine, ethylmonoethanolamine, ethyldiethanolamine, triisopropanolamine, and mixtures thereof, more preferably from methyldiethanolamine, monoisopropanolamine, polyethanolamine, monoethanolamine, and mixtures thereof. a fatty amine oxide, for example cocodimethyl amine oxide; an alkoxylated amines.

[0078] In particular, the alkoxylated amines may be of the following formula: wherein R represents a linear or branched hydrocarbon chain comprising from 1 to 30 carbon atoms, preferably from 6 to 30 carbon atoms, more preferably from 8 to 30 carbon atoms, R' represents an alkylene group comprising from 1 to 4 carbon atoms, preferably from 2 to 3 carbon atoms, more preferably R' represents an ethylene group or a propylene group, and x and y are numbers ranging from 0 to 15, with the proviso that x+y is within the range from 2 to 20, preferably from 5 to 15.

[0079] In a preferred embodiment, the alkoxylated amines are chosen from ethoxylated amines, that is to say amines of formula above wherein R' represents an ethylene group, in particular from ethoxylated fatty amines, corresponding to the following general formula: wherein R represents a linear or branched hydrocarbon chain comprising from 8 to 30 carbon atoms, preferably from 12 to 24 carbon atoms, and x+y is within the range from 2 to 20, preferably from 5 to 15. Preferably, the alkoxylated amine(s) is (are) chosen from ethoxylated fatty amines of formula, more preferably from ethoxylated tallow amines containing an average number of ethoxy units ranging from 5 to 15 (5-15 EO), ethoxylated stearyl amines containing an average number of ethoxy units ranging from 5 to 15 (5-15 EO), ethoxylated coco amines containing an average number of ethoxy units ranging from 5 to 15 (5-15 EO), ethoxylated oleyl amines containing an average number of ethoxy units ranging from 2 to 10 (2-10 EO) and mixtures thereof. Examples of particularly preferred compounds are ethoxylated tallow amine containing 5 ethoxy units (5 EO), ethoxylated tallow amine containing 10 ethoxy units (10 EO), ethoxylated stearyl amine containing 10 ethoxy units (10 EO), ethoxylated coco amine containing 10 ethoxy units (10 EO), ethoxylated oleyl amine containing 2 ethoxy units (2 EO), ethoxylated oleyl amine containing 5 ethoxy units (5 EO); at least one (poly)ethylene glycol having the following formula: wherein n is an integer ranging from 1 to 30, preferably (poly)ethylene glycols (PEG). For example the (poly)ethylene glycols are chosen from PEG-200, PEG-400, PEG-600 and mixtures thereof, and preferably PEG-600; and mixtures thereof.

[0080] According to a particular embodiment, as the scavenging efficiency of the formulated form of the oxazolidine compound(s) is enhanced, there is advantageously no need to add any booster. Thus, according to a particular embodiment, the composition of the invention does not contain any booster of the oxazolidine compound.

[0081] Preferably, the composition according to the invention is free of polyalkylene glycol, preferably is free of polyethylene glycol.Defoamer

[0082] The formulated composition of the invention may further comprise at least one defoamer. The defoamer may be silicon-based or non-silicon-based defoamer.

[0083] As example of silicon-based defoamers, mention may be made of polydimethylsiloxane polymers, more preferably from grafted polydimethylsiloxane polymers.

[0084] The defoamer is preferably a bio-based / bio-degradable and non-silicon based defoamer.

[0085] The formulated composition of the invention advantageously contains an amount of defoamer ranging from 0.1 to 10%wt, preferably from 0.5 to 5%wt, more preferably from 1 to 2.5%wt, relative to the total weight of the composition.

[0086] According to an embodiment of the invention, the formulated composition of the invention comprises, in particular consists of at least one oxazolidine compound chosen from mono-oxazolidines, bisoxazolidines and mixtures thereof and at least one aromatic solvent, especially HAN solvent, in a weight ratio oxazolidine compound(s) / aromatic solvent(s) ranging from 40 / 60 to 95 / 5, in particular 50 / 50 to 90 / 10 and more particularly 55 / 45 to 80 / 20, especially 60 / 40 to 70 / 30, said composition having a kinematic viscosity, measured at 40°C according to ASTM D445 standard, less than 14 mm 2< / s, preferably between 1 and 10 mm 2< / s.

[0087] Preferably, said composition comprises, preferably consists of: from 40 to 95 wt%, preferably from 45 to 90 wt%, more preferably from 50 to 85 wt%, even more preferably from 55 to 80 wt%, especially from 60 to 70 wt%, of oxazolidine compound(s) chosen from mono-oxazolidines, bisoxazolidines and mixtures thereof, from 5 to 60%wt, preferably from 10 to 55%wt, more preferably from 15 to 50%wt, preferably from 20 to 45 wt%, especially from 30 to 40 wt%, of an aromatic solvent(s), preferably HAN, relative to the total weight of the composition.

[0088] According to an embodiment of the invention, the formulated composition of the invention comprises, in particular consists of: at least one oxazolidine compound chosen from mono-oxazolidines, bisoxazolidines and mixtures thereof, at least one aromatic solvent, especially HAN solvent, in a weight ratio oxazolidine compound(s) / aromatic solvent(s) ranging from 40 / 60 to 95 / 5, in particular 50 / 50 to 90 / 10 and more particularly 55 / 45 to 80 / 20, especially 60 / 40 to 70 / 30, at least one defoamer, in particular in a content from 0.1 to 10%wt, preferably from 0.5 to 5%wt, more preferably from 1 to 2.5%wt, relative to the total weight of the composition; optionally one or more additive enhancing the activity of the oxazolidine compounds(s), in particular as disclosed hereabove; said composition having a kinematic viscosity, measured at 40°C according to ASTM D445 standard, less than 14 mm 2< / s, preferably between 1 and 10 mm 2< / s.

[0089] According to a particular embodiment, the above formulated compositions are free of additive enhancing the activity of the oxazolidine compound(s).

[0090] According to another embodiment of the invention, the formulated composition of the invention comprises, in particular consists of: at least one oxazolidine compound chosen from mono-oxazolidines, bisoxazolidines and mixtures thereof; at least one aromatic solvent, especially HAN solvent, in a weight ratio oxazolidine compound(s) / aromatic solvent(s) ranging from 40 / 60 to 95 / 5, in particular 50 / 50 to 90 / 10 and more particularly 55 / 45 to 80 / 20, especially 60 / 40 to 70 / 30, at least one defoamer, in particular in a content from 0.1 to 10%wt, preferably from 0.5 to 5%wt, more preferably from 1 to 2.5%wt, relative to the total weight of the composition; one or more additive enhancing the activity of the oxazolidine compounds(s), in particular as disclosed hereabove, in particular in weight ratio between the content of oxazolidine compound(s) and said booster(s) ranging from 1 to 100, preferably from 1 to 50, more preferably from 2 to 30, even preferably from 2 to 10, especially from 22 to 5; said composition having a kinematic viscosity, measured at 40°C according to ASTM D445 standard, less than 14 mm2 / s, preferably between 1 and 10 mm2 / s.

[0091] Preferably, all the compositions of the invention are free of polyalkylene glycol, preferably free of polyethylene glycol.Use

[0092] The present invention also encompasses the use of the formulated composition as described above for scavenging hydrogen sulphide and / or organic compounds comprising at least one sulfhydryl group in a liquid or gaseous stream.

[0093] The organic compounds comprising at least one sulfhydryl group are especially chosen from mercaptans, thiocarboxylic acids and dithiocarboxylic acids.

[0094] 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).

[0095] According to a preferred embodiment, the formulated composition of the invention is used for scavenging hydrogen sulphide (H 2 S) and mercaptans (compounds of formula RSH) in a hydrocarbon containing stream.

[0096] 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.

[0097] 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.

[0098] By "hydrocarbon stream" according to the invention, it is meant a stream, for example a gas stream, that contains mainly hydrocarbons but may contain a minor quantity of water, in particular in a content less than1 % vol.

[0099] Such streams contain H 2 S and / or mercaptans in total amounts which may range for example from 1 to 10 000 ppm by weight.

[0100] In particularly preferred embodiment, the formulated composition of the invention is used for treating a gas stream, preferably a hydrocarbon gas stream, for example a sour gas stream for natural gas production, for example in the gas treatment unit of an oil production device.

[0101] According to another of its aspects, the present invention also concerns the use of an organic solvent, preferably an organic hydrocarbon solvent, more preferably an aromatic solvent, preferably HAN, for improving the efficiency of an oxazolidine compound for scavenging hydrogen sulphide and / or organic compounds comprising at least one sulfhydryl group in a liquid or gaseous stream, in particular in hydrocarbon stream such as crude oil, fuel or natural gas.

[0102] Preferably, the use is for improving the efficiency of oxazolidine compound(s) in scavenging hydrogen sulphide and organic compounds comprising at least one sulfhydryl group contained in a hydrocarbon gas stream, in particular in a sour gas stream for natural gas production, in which said oxazolidine compound(s) is formulated with said solvent, preferably HAN, and the formulated form is injected into the gas stream to be treated.

[0103] Preferably, the weight ratio oxazolidine compound(s) / solvent(s) ranges from 40 / 60 to 95 / 5, in particular 50 / 50 to 90 / 10 and more particularly 55 / 45 to 80 / 20, especially 60 / 40 to 70 / 30.

[0104] Preferably, the solvent, preferably HAN, is used to prepare a formulated composition according to the invention, as disclosed above. Thus, the specific embodiments as defined above for the formulated composition of the invention also define particular embodiments of the claimed use and method according to the invention.

[0105] The present invention also relates to the use of a formulated composition comprising at least one organic solvent, preferably at least one organic hydrocarbon solvent, more preferably at least one aromatic solvent, and more preferably HAN and at least one oxazolidine compound, to improve scavenging of hydrogen sulphide and / or organic compounds comprising at least one sulfhydryl group in a liquid or gaseous stream, preferably in a hydrocarbon gas stream, in comparison with a composition of 100 wt% of said oxazolidine compound.

[0106] The solvent and the oxazolidine compound are preferably such as described below.Method

[0107] 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 a formulated composition of the invention.

[0108] 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).

[0109] 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.

[0110] The amount formulated composition used per amount of stream depends on the concentration of said oxazolidine compound(s) in the formulated 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.

[0111] The formulated 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.

[0112] Preferably, the formulated composition according to the invention is injected in the stream where the stream is in gas phase.

[0113] In particularly preferred embodiment, the method of the invention is for treating a hydrocarbon gas stream, in particular a sour gas stream for natural gas production, for example in the gas treatment unit of an oil production device.

[0114] Preferably, the reduction of the amount of sulphur compounds in the gas stream is particularly improved when the composition according to the invention is injected downstream the high-pressure separator, currently used in the gas treatment unit for production natural gas.

[0115] In a preferred embodiment, the composition of the invention is injected through a quill injector. By "quill injector", it is meant an injection device without any nozzle.

[0116] A quill injector differs from a quill with an atomizer head.

[0117] The present invention also relates to a method for improving scavenging properties of an oxazolidine compound comprising the step of formulating said oxazolidine compound with an organic solvent, preferably an organic hydrocarbon solvent, in particular an aromatic solvent, preferably HAN, preferably HAN.

[0118] Preferably, the formulation is such that the active content of the formulated product is from 40 to 95 wt%, in particular from 50 to 90 wt%, more particularly from 55 to 80 wt% and preferably from 60 to 80 wt%.

[0119] The example hereafter only aims at illustrating the present invention, and shall not be interpreted so as to limit its scope.Examples Tested scavenging products

[0120] C1 is a scavenging product of 100% MBO. C1 has a kinematic viscosity at 40°C, measured according to ASTM D445 of 14.73 mm 2< / s.

[0121] A1 is a formulated composition according to the invention comprising 60 wt% of MBO and 40 wt% of HAN having a kinematic viscosity at 40°C, measured according to ASTM D445 of 2.7 mm 2< / s.

[0122] The performances of the two scavenging products were evaluated in a field test by injecting them in the gas treatment unit of an oil production plant. Injection point of H2S scavenger is located downstream high-pressure separator in gas outlet. Gas flow rate at the injection location during field test was estimated at an average of 12,243 MSm 3< / d. The products were injected using an injection quill device without any atomizer head.

[0123] The scavenging potential was evaluated in comparison with MEA Triazine.

[0124] Performances of the composition C1 and A1 are evaluated by the difference of MEA triazine injected downstream. If the composition injected shows improved performances in H 2 S scavenging, the MEA triazine injection will be reduced as the H 2 S measurement at the export is a fixed target.

[0125] The results have showed an increase performance with the formulated composition according to the invention (A1) in comparison with the pure MBO (C1).

[0126] It was estimated that 1L of pure MBO (C1) was able to replace from 1,6 to 2,2 L of MEA Triazine, whereas 1L of formulated MBO (A1) was able to replace from 3 up to 3,5 L of MEA Triazine.

[0127] Thus, even with a reduced active content of MBO (60wt% active content), a formulated composition according to the invention makes it possible to achieve improved scavenging performance in comparison with pure MBO.

Claims

1. Composition, in particular useful for scavenging hydrogen sulphide and mercaptans in hydrocarbon streams, said composition comprising at least one oxazolidine compound and at least one hydrocarbon solvent, in particular aromatic solvent, especially Heavy Aromatic Naphta (HAN) solvent, in a weight ratio oxazolidine compound(s) / aromatic solvent(s) ranging from 40 / 60 to 95 / 5, said composition having a kinematic viscosity, measured at 40°C according to ASTM D445 standard, less than 14 mm2 / s, preferably between 1 and 10 mm2 / s.

2. Composition according to claim 1, wherein the oxazolidine compound(s) is (are) chosen from compounds comprising one oxazolidine cycle (i.e. mono-oxazolidines) or two oxazolidine cycles (i.e. bisoxazolidines), preferably from 1,3-oxazolidine, 5-methyloxazolidine, 3-(C1-C20)alkyl-oxazolidines, 3,3'-methylenebis(oxazolidine), 3,3'-methylenebis(5-methyloxazolidine) (MBO) and mixtures thereof.

3. Composition according to claim 1 or 2, wherein the aromatic solvent is an Heavy Aromatic Naphta (HAN) solvent.

4. Composition according to any one of the preceding claims, further comprising at least one defoamer, preferably chosen from silicon and non-silicon based defoamers.

5. Composition according to any one of the preceding claims, wherein the weight ratio oxazolidine compound(s) / aromatic solvent(s) ranges from 50 / 50 to 90 / 10, preferably from 55 / 45 to 80 / 20, especially from 60 / 40 to 70 / 30.

6. Composition according to any one of the preceding claims, wherein the weight ratio oxazolidine compound(s) / aromatic solvent(s) ranges from 60 / 40 to 70 / 30.

7. Composition according to any one of the preceding claims, wherein the kinematic viscosity, measured at 40°C according to ASTM D445 standard is between 1 and 10 mm2 / s.

8. Use of an organic solvent, preferably an organic hydrocarbon solvent, in particular an aromatic solvent, preferably HAN, for improving the efficiency of oxazolidine compound(s) in scavenging hydrogen sulphide and organic compounds comprising at least one sulfhydryl group contained in a liquid or gaseous stream, in particular in a hydrocarbon stream such as crude oil, fuel or natural gas.

9. The use according to the preceding claim for improving the efficiency of oxazolidine compound(s) in scavenging hydrogen sulphide and organic compounds comprising at least one sulfhydryl group contained in a hydrocarbon gas stream, in particular in a sour gas stream for natural gas production, in which said oxazolidine compound(s) is formulated with said solvent, preferably HAN, and the formulated form is injected into the gas stream to be treated.

10. The use according to claim 8 or 9, wherein said solvent is a HAN solvent.

11. The use according to any one of claims 8 to 10, wherein the weight ratio oxazolidine compound(s) / solvent(s) ranges from 40 / 60 to 95 / 5, preferably from 50 / 50 to 90 / 10, preferably from 55 / 45 to 80 / 20, especially from 60 / 40 to 70 / 30.

12. The use according to any one of claims 8 to 11, wherein the weight ratio oxazolidine compound(s) / solvent(s) ranges from 60 / 40 to 70 / 30.

13. 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 7.

14. The method according to the preceding claim, for treating a hydrocarbon gas stream, in particular a sour gas stream for natural gas production, in which said composition is injected into the gas stream.

15. The method according to claim 13 or 14, wherein the injection is operated by using a quill injector.

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