US20250290003A1

US20250290003A1 - Cluster-Structured, Sulfur Scavenging Composition and Processes for Scavenging Sulfhydryl Moieties in Hydrocarbon Streams

Info

Publication number: US20250290003A1
Application number: US19/082,814
Authority: US
Inventors: Jason Martin THOMPSON
Original assignee: Individual
Current assignee: Individual
Priority date: 2024-03-18
Filing date: 2025-03-18
Publication date: 2025-09-18
Also published as: WO2025199120A1

Abstract

This invention pertains to processes and compositions for scavenging sulfhydryl moieties such as hydrogen sulfide from hydrocarbon streams, especially gas streams.

Description

CROSS-REFERENCE TO A RELATED APPLICATION

This application claims priority to U.S. Provisional Patent Application Ser. No. 63/566,597, filed Mar. 18, 2024; which is incorporated by reference herein in its entirety.

FIELD OF THE INVENTION

BACKGROUND OF THE INVENTION

The removal of hydrogen sulfide from hydrocarbon streams, especially gas streams, is often required in order to meet many pipeline and storage regulations. Hydrogen sulfide and mercaptans are toxic and have an offensive odor, and these components can be adverse to downstream process equipment. Even in situations where the gas stream is flared, the presence of hydrogen sulfide and mercaptans result in the generation of pollutants such as sulfur dioxide and removal of these sulfur compounds may be mandated.
Numerous processes have been proposed for the removal of hydrogen sulfide and mercaptans including adsorption, absorption and reactions with chemical agents. Since it is desired to remove hydrogen sulfide and mercaptans at the source of the hydrocarbon stream in order to permit pipeline transport and storage or flaring, the processes need to be able to be operated under the conditions of the environment at the source. Often, the sources are remotely located and may be subject to harsh environments such as would be the case with natural gas wells. Because of such remote locations, minimization of operating problems is particularly desirable.
One type of process for removal of hydrogen sulfide uses hydrogen sulfide scavengers that react with hydrogen sulfide to provide a substantially non-toxic compound or a compound which can be removed from the hydrocarbon. Currently most frequently used hydrogen sulfide scavengers are hexahydrotriazines from monoethanolamine (MEA triazine) and methylamine (MMA triazine). These triazines are readily deployable in scrubbers or in a production train that can be physically located adjacent to hydrocarbon sources such as gas wells, are effective scavengers, and result in the formation of dithiazines. Moreover, MEA triazine and MMA triazine are readily available at reasonable costs. Nevertheless, these triazines are susceptible to the formation of solids, especially dithiazine deposits, that can result in operational difficulties and the necessity for maintenance of the scrubber system. Removal of solid deposits can be difficult and result in lost operational time. Additionally, the formation of dithiazine solids often occurs prior to all of the triazine being converted to dithiazine. Accordingly, the scrubbing is generally ceased with less than all, and frequently less than about 75 percent, of the triazine having been converted to dithiazine.
U.S. Pat. Nos. 9,493,711 B2 and 10,626,334 B2 disclose a significant advance in the scavenging of sulfhydryl moieties using triazines. The patents disclose using at least one substituted hexahydrotriazine that is substantially devoid of hydroxyl groups but is soluble in water such as MMA triazine with an amphiphilic moiety. Amphiphilic moieties disclosed are hydroxyl or alkoxy-containing organic compounds having at least about 4 to 20 carbon atoms and may be hexahydrotriazines substituted with hydroxyalkyl and alkoxyalkylene groups of 1 to 20 carbon atoms, preferably 2 to 6 carbon atoms. Representative amphiphilic moieties include, but are not limited to triazines such as MEA triazine, MOPA triazine (1,3,5 tris-(3-methoxypropyl)-hexahydrotriazine), and 1,3,5 (tris-methoxyethyl) hexahydrotriazine and partially or fully spent derivatives thereof; benzyl alcohol, benzyl ethers of 1 to 6 carbons; phenol; and alkylphenolalkoxylates of up to 30 carbons, preferably with a low degree of alkoxyloxylation, e.g., 1 to 4 alkyleneoxy groups. The disclosed compositions provide micelles as the triazine is converted to dithiazine, and triazines can remain in or active at the surface of an aqueous phase to react with sulfhydryl moieties until they become spent.
Further improvements in scavenging sulfhydryl moieties from hydrocarbon streams are sought that offer improved up-take of sulfhydryl moieties both in terms of rate of up-take and amount of up-take per unit mass of scavenger, especially improvements that are cost effective.

BRIEF SUMMARY OF THE INVENTION

By this invention, processes and compositions for scavenging sulfhydryl are provided that increase at least one of the up-take rate and up-take capacity of sulhydryls from hydrocarbon streams.
The processes and compositions of this invention are operable in, for example, existing scrubbing systems and for continuous injection in a production train for the removal of hydrogen sulfide from hydrocarbon streams, and are operable in the presence of water. Further, the processes are operable at low temperatures without the formation of solids.
The processes and compositions of this invention involve the use of performance-enhancing compositions (packages) that, in certain embodiments, foster the formation of cluster structures containing scavenger, which structures retain stability even as the scavenger becomes spent by retaining the spent scavenger molecules in the cluster structure. Thus, the formation of solids, amorphous or crystalline, can be reduced or avoided.
In alternative embodiments, the cluster structures can be designed to collapse once the scavenger has become spent to a desired degree, i.e., when the potential energy of the scavenger has been sufficiently altered by reaction with sulfhydryl that the cluster structure is no longer stable. The performance enhancing packages also facilitate the transfer of sulfhydryl moieties to unspent scavenger, thereby increasing the up-take of sulfhydryl by the scavenger.
Advantageously, the benefits of this invention can be achieved using any amine-based scavenger, including economically-advantaged scavengers such as, e.g., MEA triazine and MMA triazine.
While not wishing to be limited to theory, it is believed that the packages together with amine-based scavenger in an aqueous medium provide multimolecular clusters containing the scavenger that are formed through physical and ionic association or attraction among the components of the package. The package provides, in part, molecules that have positive and negative charges that are able to associate with the positive and negative charges of the scavenger to provide a multimolecular cluster that has a dynamic potential energy interface to the cluster. Moreover, the potential energy interface can facilitate the transport of sulfhydryl moieties to and within the cluster structure. Further, the multimolecular clusters can interact with other components in the scavenger composition, such as water and other clusters, through the dynamic potential energy interfaces and thus affect the properties of the scavenger composition overall.
For example, the interaction of clusters with other components in the scavenger often results in an increase in composition viscosity as compared to a composition not containing the package, all else being substantially the same. Stable cluster structures as contemplated by this invention can be formed using a wide range of amine-based scavengers even though they differ in positive and negative sites that create the ionic attraction. Moreover, the scavenger can change the number of positive and negative sites and the strength of the sites as it becomes spent. The components of the package of this invention provide a robustness to the cluster structure and thereby enhance cluster stability over a range of amine-based scavengers and over the changes in the scavengers as they become spent. In this regard, for instance, where the sulfur scavenger is triazine, the formation of dithiazine occurs within the cluster, and it is believed that the dynamics of the cluster inhibit the formation of amorphous or crystalline solids of dithiazine.
Accordingly, the subject invention facilitates high up-takes of sulfhydryl moieties without undue risk of adverse solids formation. Moreover, the dynamic potential energy interface of the cluster can facilitate transport of sulfhydryl moieties to the cluster even as the sulfur scavenger approaches its point of being totally spent.
In certain embodiments, the sulfhydryl scavenger performance-enhancing additive (package) of this invention comprises a polyhydroxylated hydrocarbon, a hydrocarbyl alcohol, an organic acid or salt thereof, and optionally, a water-dispersible, metal-containing, dielectric component.
In certain embodiments, the package comprises:

- a. a polyhydroxylated hydrocarbon comprising at least 2 to about 10 carbons and a hydroxy-terminated, poly(alkylene oxide) having a weight average molecular weight of up to about, e.g., 20,000;
- b. a hydrocarbyl alcohol having a terminal hydroxy group and about, e.g., 5 to 24 carbons, at least one of which is a tertiary carbon;
- c. an organic acid or salt thereof having at least one carboxyl or phosphonyl substituent, preferably an amine having at least one amino moiety substituted with two carboxyl or two phosphonyl moieties, and
- d. optionally, a water-dispersible, metal-containing, dielectric component,
- wherein the hydrocarbyl alcohol is provided in said composition to provide a mole ratio of hydroxyls in the hydrocarbyl alcohol per hydroxyl of the polyhydroxylated hydrocarbon of between about, e.g., 1:100 to 50:100, preferably between about 2:100 to 20:100;
- the organic acid or salt thereof is provided in said composition to provide a mole ratio of acid moieties per hydroxyl of the polyhydroxylated hydrocarbon of between about, e.g., 5:100 to 25:100, preferably between about 5:100 to 20:100; and
- the dielectric component, if used, is provided in a mass ratio to the polyhydroxylated hydrocarbon of between about, e.g., 0.01:1000 to 20:1000, preferably between about 0.05:1000 to 10:1000.

In certain embodiments, the sulfhydryl scavenger composition of this invention comprises at least one amine-based sulfur scavenger and between about, e.g., 0.05 to 1, preferably between about 0.1 to 0.5, parts by mass of the package (on an anhydrous basis) to amine-based sulfur scavenger.
In certain embodiments, the subject invention further provides methods for reducing an amount of sulfhydryl moieties in a hydrocarbon stream, which comprises contacting, in the presence of water, said hydrocarbon stream with a sulfhydryl composition comprising at least one amine-based sulfur scavenger and a sulfhydryl scavenger performance-enhancing additive according to the subject invention. In certain embodiments, said additive comprises:

- a. a polyhydroxylated hydrocarbon of at least one of 2 to about 10 carbons and hydroxy-terminated, poly(alkylene oxide) having a weight average molecular weight of up to about, e.g., 20,000;
- b. a hydrocarbyl alcohol having a terminal hydroxy group, about, e.g., 5 to 24 carbons, at least one of which is a tertiary carbon;
- c. an organic acid or salt thereof having at least one carboxyl or phosphonyl substituent, preferably an amine having at least one amino moiety substituted with two carboxyl or two phosphonyl moieties, and
- d. optionally, a water-dispersible, metal-containing, dielectric component,
- wherein the hydrocarbyl alcohol is provided in said composition to provide a mole ratio of hydroxyls in the hydrocarbyl alcohol per hydroxyl of the polyhydroxylated hydrocarbon of between about, e.g., 1:100 to 50:100, preferably between about 2:100 to 20:100;
- the organic acid or salt thereof is provided in said composition to provide a mole ratio of acid moieties per hydroxyl of the polyhydroxylated hydrocarbon of between about, e.g., 5:100 to 25:100, preferably between about 5:100 to 20:100; and
- the dielectric component is provided in a mass ratio to the polyhydroxylated hydrocarbon of between about, e.g., 0.01:1000 to 20:1000, preferably between about 0.1:1000 to 10:1000.

Advantageously, the subject invention can improve the production of oil and natural gas by, for example, reducing equipment corrosion, improving the quality of produced oil and gas, and reducing the operational and environmental hazards caused by sulfhydryl compounds.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a depiction of the test setup used to evaluate sulfur loading and reaction kinetics.

FIG. 2 is a graph of the reaction kinetics.

FIG. 3 is an annotated graph of the reaction kinetics.

FIG. 4 is a graph of a higher temperature profile reaction kinetics.

DETAILED DESCRIPTION OF THE INVENTION

All patents, published patent applications and articles referenced herein are hereby incorporated by reference in their entirety.

Selected Definitions

As used herein, the following terms have the meanings set forth below unless otherwise stated or clear from the context of their use.
Ranges provided herein are understood to be shorthand for all of the values within the range. For example, a range of 1 to 20 is understood to include any number, combination of numbers, or sub-range from the group consisting 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 and 20, as well as all intervening decimal values between the aforementioned integers such as, for example, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 1.13, 1.135, and so forth. With respect to sub-ranges, “nested sub-ranges” that extend from either end point of the range are specifically contemplated. For example, a nested sub-range of an exemplary range of 1 to 50 may comprise 1 to 10, 1 to 20, 1 to 30, and 1 to 40 in one direction, or 50 to 40, 50 to 30, 50 to 20, and 50 to 10 in the other direction.
As used herein, “reduces” means a negative alteration of at least 0.001%, 0.01%, 0.1%, 1%, 5%, 10%, 25%, 50%, 75%, or 100%, and “increases” means a positive alteration of at least means a negative alteration of at least 0.001%, 0.01%, 0.1%, 1%, 5%, 10%, 25%, 50%, 75%, or 100%.
The transitional term “comprising,” which is synonymous with “including,” or “containing,” is inclusive or open-ended and does not exclude additional, unrecited elements or method steps. By contrast, the transitional phrase “consisting of” excludes any element, step, or ingredient not specified in the claim. The transitional phrase “consisting essentially of” limits the scope of a claim to the specified materials or steps “and those that do not materially affect the basic and novel characteristic(s)” of the claimed invention. Use of the term “comprising” contemplates embodiments that “consist” or “consist essentially” of the recited component(s).
Unless specifically stated or obvious from context, as used herein, the term “or” is understood to be inclusive. Unless specifically stated or obvious from context, as used herein, the terms “a,” “and” and “the” are understood to be singular or plural.
Unless specifically stated or obvious from context, as used herein, the term “about” is understood as within a range of normal tolerance in the art, for example within 2 standard deviations of the mean. About can be understood to be within 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, 0.5%, 0.1%, 0.05%, 0.01%, 0.001% or 0.0001% of the stated value.
The recitation of a listing of chemical groups in any definition of a variable herein includes definitions of that variable as any single group or combination of listed groups.
The recitation of an embodiment for a variable or aspect herein includes that embodiment as any single embodiment or in combination with any other embodiments or portions thereof.
All parts, percentages and ratios are on an anhydrous basis unless otherwise stated or clear from the context.
As used herein, “applying” a composition or product refers to contacting it with a target or site such that the composition or product can have an effect on that target or site.
As used herein, a “hydrocarbon stream” is a liquid or preferably gaseous stream containing hydrocarbon and may be an industrial or refining stream or a fossil fuel stream, e.g., from a well bore.
As used herein, “ionically attracted” or “ionically associated” means that van der Waals forces or similar forces attract molecules together, in some instances due to electrostatic actions such as between a hydroxyl oxygen and a sulfhydryl hydrogen, without the formation of a covalent or ionic bond.
As used herein, a “dielectric component” is a material that has the ability to store electrostatic charges and release electrostatic charges. The charges can be from electrons, ions, molecular dipoles and the like.
The term “triazine” as used herein refers to substituted and unsubstituted hexahydrotriazine.
As used herein, a “spent triazine” is a thiadiazine, dithiazine or trithiane. It should be understood that a thiadiazine may become further spent and form a dithiazine, and a dithiazine may become further spent to form a trithiane. Although sulfhydryl moieties may become ionically attracted to and associated, but not reacted, with a nitrogen, this association is not determinative as to whether or not a triazine is spent.
As used herein, the term “sulfhydryl” is used in a manner inconsistent with its common meaning in that it is used to include any compounds or chemical species comprising one or more sulfur atoms or ions, including but not limited to hydrogen sulfide, mercaptans, polysulfides, or combinations thereof. The sulfhydryl compounds are preferably represented by the formula R—S—H wherein R is hydrogen or alkyl of 1 to 6 carbon atoms. Furthermore, a sulfhydryl has a bisulfide anion with the formula HS⁻. As used herein, “water-dispersible dielectric material” is a dielectric material that is itself water soluble or dispersible or is in combination with another material (dispersing aid) that enables the dielectric material to be suspended in an aqueous solution. Dispersing aids include, but are not limited to, sequestering agents, surfactants, especially non-ionic surfactants, and water-soluble polymer or copolymer which include the dielectric material as part of the backbone or encases the dielectric material. The term “dispersible” means that the material is dissolved or is capable of being suspended without agitation.
As used herein, a “surfactant” is a surface active agent having two functional groups, namely a hydrophilic (water-soluble) or polar group and a hydrophobic (oil-soluble) or non-polar group. The hydrophobic group is usually a long hydrocarbon chain (e.g., C8-C18), which may or may not be branched, while the hydrophilic group can be formed by moieties such as, for example, carboxylates, sulfates, sulfonates (anionic), alcohols, polyoxyethylenated chains (nonionic) and quaternary ammonium salts (cationic).

Packages

In certain embodiments, the subject invention provides sulfhydryl scavenger performance-enhancing additives (a.k.a. “packages”) for enhancing the performance of sulfhydryl scavenger compositions.
In preferred embodiments, enhancing the performance of a sulfhydryl scavenger involves at least one of: increasing the rate of up-take of sulfhydryl moieties by the scavenger, and increasing the amount of sulfhydryl moiety taken-up by the scavenger prior to the loss of effectiveness, as compared to the composition not containing the package. Loss of effectiveness can occur when, for example, the rate of sulfhydryl moiety is unattractive from a commercial standpoint or crystalline or amorphous solids are generated and adversely affect processability and/or equipment.
In certain embodiments, the sulfhydryl scavenger performance-enhancing additive (package) of this invention comprises a polyhydroxylated hydrocarbon, a hydrocarbyl alcohol, an organic acid or salt thereof, and optionally, a water-dispersible, metal-containing, dielectric component.
In certain embodiments, the package contains one or more polyhydroxylated hydrocarbons comprising, e.g., 2 to 10 carbons, 2 to 8 carbons, or 2 to 6 carbons, and a hydroxy terminated poly(alkylene oxide) comprising an alkylene comprising, e.g., 2 to 10 carbons, 2 to 8 carbons or 2 to 6 carbons. In certain embodiments, the polyhydroxylated hydrocarbon has an average molecular weight from about, e.g., 100 to 100,000, 150 to 75,000, 200 to 50,000, 250 to 25,000, or 300 to 20,000, although higher molecular weight polymers can also be used. In some instances, the hydroxyls are positioned on vicinal carbons. In some instances, at least one hydroxyl is on a terminal carbon.
In preferred embodiments, the polyhydroxylated hydrocarbon is one that has solubility in water, preferably at least, e.g., 250, at least 300, at least 350, at least 400, at least 450, at least 500, at least 550, at least 600, or at least 650 grams per liter at 25° C. Also in preferred embodiments, the polyhydroxylated hydrocarbon is one in which the sulfhydryl moiety and the scavenger have solubility, preferably at least, e.g., 50, at least 75, at least 100, at least 125, at least 150, at least 175 or at least 200 grams per liter at 25° C.
Examples of polyhydroxylated hydrocarbons include, but are not limited to, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,3-propanediol, 1,2-butanediol, glycerol, 1,2,4-butanetriol, polyethylene glycol and polypropylene glycol. Preferred polyhydroxylated hydrocarbons do not result in packages having undue viscosity at 25° C., e.g., the absolute viscosity of the package is preferably less than about 10,000, preferably less than about 5000, mPa-s at 25° C. Glycerol is frequently used due to its efficacy, low volatility, low toxicity and comparatively low cost.
Without wishing to be limited by theory, it is believed that the polyhydroxylated hydrocarbon ionically associates with the scavenger to provide additional hydroxyl charges to the scavenger, even after the nitrogen in the scavenger is consumed or replaced, as is the case with triazines. The excess hydroxyl charges are believed to increase the electrostatic repulsion of the sulfuydryl moiety and allow an attack to provide bisulfite to facilitate reacting or bonding with the scavenger. It is further believed that the cosolvent properties of the polyhydroxylated hydrocarbon enable the clusters to be formed and stabilized by providing hydroxyl functionality for ionic association with other components of the structure.
In certain embodiments, the package also contains an organic acid or salt thereof having at least one carboxyl or phosphonyl substituent. In preferred embodiments, the organic acid or salt thereof is an amine having at least one amino moiety substituted with two carboxyl or two phosphonyl moieties. Where the organic acid is a salt, the salt is often water soluble, e.g., a sodium or potassium salt.
In some embodiments, the organic acid contains between about, e.g., 1 to 20, 2 to 18, 4 to 16, 6 to 14, or 8 to 12 carbons, preferably between 2 to 6 carbons.
The organic acid or salt thereof can be provided in the package to provide a mole ratio of acid moieties per hydroxyl of the polyhydroxylated hydrocarbon of between about, e.g., 1:00 to 50:100, 2:100 to 40:100, 3:100 to 35:100, 4:100 to 30:100, or 5:100 to 25:100, preferably between about 5:100 to 20:100. One class of preferred organic acids includes acids having two or more acid groups such as, e.g., oxalic acid, glutaric acid, succinic acid, citric acid, phthalic acid and the like. The acid may be an amino acid, e.g., an amine having at least one amino moiety, and preferably at least two amino moieties, substituted with two carboxyl or two phosphonyl moieties. Examples of amino acids include, but are not limited to, iminodiacetic acid, N-methyliminodiacetic acid, N-ethyliminodiacetic acid, N-hydroxyethyl iminodiacetic acid, ethylenediamine tetraacetic acid, diethylenetriamine pentaacetic acid, imidodiphosphoric acid, ethylamino diphosphonic acid, ethylenediamine tetra(methylene phosphonic acid), and diethylenetriamine penta(methylene phosphonic acid). Ethylenediamine tetraacetic acid is often used due to its efficacy, low volatility, low toxicity and cost.
Without wishing to be limited by theory, it is believed that the organic acid assists in forming clusters. Further, where the acid is an amino acid, the nitrogen provides sites for sorption of sulfhydryl moieties. In one aspect, the sorbed sulfhydryl is held up for reaction with the sulfur scavenger, and in another aspect, it increases the sulfhydryl up-take of the scavenger composition. The acid also serves to dielectrically affect the scavenger composition due to its ability to influence the balance between hydroxyl and hydronium tails in the formulation. It is believed that the acid concentration in the scavenger composition contributes to the robustness of the cluster structures together with the dielectric. In general, all else the same, higher concentrations of acid promote greater stabilities as the scavenger becomes spent. Accordingly, if it is desired to have the cluster collapse prior to the scavenger being fully spent, lesser amounts of acid are used.
In certain embodiments, the package contains hydrocarbyl alcohol having a terminal hydroxy group and about, e.g., 6 to about 24 carbons, about 8 to 22 carbons, about 10 to 20 carbons, or about 12 to 18 carbons. In preferred embodiments, at least one of the carbons is a tertiary carbon. In a further preferred embodiment, the tertiary carbon has a hydroxy ethyl substituent, and at last 5 of the carbons have only hydrogen substituents. Thus, the alcohol has hydrophobic properties useful for forming clusters and also has the ability, through the tertiary carbon, to associate with sulfhydryl moieties. The alcohol preferably has a solubility in water at 25° C. of less than about 100, preferably less than about 50, less than about 40, less than about 30, or less than about 20 grams per liter.
In certain embodiments, the hydrocarbyl alcohol is provided in the package to provide a mole ratio of hydroxyls in the hydrocarbyl alcohol per hydroxyl of the polyhydroxylated hydrocarbon of between about, e.g., 1:100 to 50:100, 2:100 to 45:100, 3:100 to 40:100, 4:100 to 35:100, 5:100 to 30:100, 6:100 to 25:100, 7:100 to 20:100, or 8:100 to 15:100, preferably between about 2:100 to 20:100.
In preferred embodiments, the hydrocarbyl alcohol has low volatility, and often the hydrocarbyl alcohol has a normal boiling point at or greater than about, e.g., 120° C., 130° C., 140° C., and sometimes at or greater than about 150° C. Examples of alcohols include, but are not limited to, 2-methylpentan(l)ol, 4-methylcyclohexanol, 3-propylcyclohexanol, 3-ethylpentanol, 2-ethylhexanol, 4-ethylhexanol, phenol, cyclohexanol, 2-isopropylphenol, 4-isobutylphenol, 4-isopropylphenol, 2-methyloctanol, 2-ethyloctanol, 2-propyl-1-butanol, and 4-(2,4-dimethylheptan-3-yl) phenol.
Without wishing to be limited by theory, it is believed that the weak hydrogen to carbon covalent bonds on the alcohol, especially those on a tertiary carbon, facilitate ionic association with the oxygen moieties of the organic acid or salt thereof, which association can assist in forming a cluster. Further, the hydrocarbyl alcohol can, in some instances, provide a hydrophobic phase or region during the formation of the clusters. It is also believed that water, which is more polar than the hydrocarbyl alcohol, ultimately displaces the hydrocarbyl alcohol in the cluster. The hydrocarbyl alcohol, having little, if any, solubility in water, is believed to the interface between the organic (sulfhydryl moiety-containing phase) and the aqueous, scavenger phase. Indeed, where the hydrocarbyl alcohol has been used in a substantial excess, a liquid layer of the hydrocarbyl alcohol has been observed to occur at the interface between the organic and aqueous phases. The more organic interface, due to the presence of the hydrocarbyl alcohol, facilitates migration of the sulfhydryl moiety across the interface and into association with the hydrocarbyl alcohol. The sulfhydryl moieties now in the aqueous phase passes to clusters for reaction with the scavenger. The sulfhydryl moiety can pass to a cluster, a cluster can contact the hydrocarbyl alcohol laden with the sulfhydryl moiety or the hydrocarbyl alcohol laden with the sulfhydryl can migrate to a cluster. The hydrocarbyl alcohol can also minimize solids, if present, sticking to each other or to walls of the treatment vessel, and, where amorphous polymers are formed in the scavenging of the sulfhydryl moieties, enhance the flowability of the solution.
In certain embodiments, the package can contain other components as well, such as, for example, a water-dispersible, dielectric component. While not wishing to be limited by theory, it is believed that the dielectric component interacts with the sulfur scavenger, that is, the component in the composition that removes, by reaction or association, the sulfhydryl moiety from a hydrocarbon stream containing the sulfhydryl moiety. This interaction serves, in part, to stabilize the forces attracting a sulfhydryl moiety to the sulfur scavenger. It is believed that an electrical field exists around the sulfur scavenger due to polar positive and/or polar negative sites on the sulfur scavenger and this electrical field influence the rate of transport of the sulfhydryl moieties to the scavenger sites. This electrical field can be affected by other components in the composition. The dielectric component can also attenuate changes due to the sulfuydryl moiety reacting or associating with sites on the sulfur scavenger.
In certain embodiments, the dielectric component, if used, is provided in a mass ratio to the polyhydroxylated hydrocarbon of between about, e.g., 0.001:1000 to 50:1000, 0.01:1000 to 40:1000, 0.1:1000 to 30:1000, 1:1000 to 25:1000, or preferably, between about 0.05:1000 to 10:1000.
In certain embodiments, the water-dispersible, metal-containing, dielectric component contains one or more metallic elements, which can be present as the metal or in a compound bonded to other atoms. Examples of metallic atoms include, but are not limited to, magnesium, calcium, barium, titanium, zirconium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, manganese, iron, cobalt, nickel, copper, zinc, aluminum, gallium, silicon, germanium, selenium, tin, lead, and bismuth. These metals can be in the form of oxides, carbides, carbonates, nitrides, nitrates, sulfides, sulfates or borates or in multi-metallic atom compounds such as aluminates, molybdates, titanates, tantalates, silicates, niobates, zirconates, and the like, and can be in amorphous or structured, including crystalline structures, such as ceramics, clays, crystals, glasses and the like. The dielectric component preferably has a dielectric constant of at least about e.g., 2.0 to 2.5, preferably between about, e.g., 2.0 to 200, 2.25 to 150, 2.5 to 100, 2.75 to 75, or 3.0 to 50. Dielectric components can be, for example, nanoparticles sufficiently small to be dispersed in water. In some embodiments, the metallic atoms can be present within a polymeric structure, which polymer is water soluble or otherwise dispersible in or in association with a hydrophilic surfactant or hydrophilic chelating agent or within a polymer matrix that is water soluble or otherwise dispersible.
A commonly available polymeric structure containing metal atoms is poly(dimethylsiloxane)-containing homopolymers and copolymers, especially with ethylene oxide, that contain dimethylsiloxane. The water solubility or dispersibility of polymers containing metallic atoms can be enhanced through copolymerization (random or block) with monomers providing hydrophilic polymers such as polyethylene glycol, polyvinyl acetate and polyvinyl alcohol. In some embodiments, these polymers and copolymers have a weight average molecular weight between about, e.g., 400 and 150,000, 450 and 125,000, 500 and 100,000, 550 and 80,000, 600 and 75,000, 650 and 65,000 or 700 and 50,000. Where the metallic atoms are dispersed using surfactants, the surfactants are preferably non-ionic. Poly(alkyleneoxide)-containing surfactants are readily available and have relatively low toxicity. Other non-ionic surfactants include, but are not limited to, polysorbates, polyglycerols, polyglycosides, stearates and the like.
Where the metallic atoms are dispersed using chelating agents, the chelating agents are preferably hydrophilic. Chelating agents according to the subject invention can include, but are not limited to, oxalic acid, succinic acid, citric acid, phthalic acid, ethylenediamine tetraacetic diethylenetriamine acid, pentaacetic acid, imidodiphosphoric acid, ethylamino diphosphonic acid, ethylenediamine tetra(methylene phosphonic acid), and diethylenetriamine penta(methylene phosphonic acid).
Polymer matrices that can be used to contain metallic atoms include, but are not limited to, hydrogels and anisotropic polymeric structures, e.g., structures with dense skins and porous interiors. Polymer matrices can be composed of any suitable polymer. Examples of polymers include, but are not limited to, polyvinyl alcohol, polyethylene glycol, acrylate polymers and copolymers, polyvinylpyrrolidone, and polysulfonates, which polymers may be crosslinked.
Other additives useful in the scavenger composition may be included in the package or added to the scavenger composition directly.
In some embodiments, the additional additives include a carrier fluid, such as aqueous fluids, non-aqueous fluids, and any combinations thereof. Suitable aqueous fluids may comprise water from any source. Such aqueous fluids may comprise fresh water, salt water (e.g., water containing one or more salts dissolved therein), brine (e.g., saturated salt water), seawater, or any combination thereof.
In most embodiments of the present disclosure, the aqueous fluids comprise one or more ionic species, such as those formed by salts dissolved in water. For example, seawater and/or produced water may comprise a variety of divalent cationic species dissolved therein.
In certain embodiments, the density of the aqueous fluid can be adjusted, among other purposes, to provide additional particulate transport and suspension in the compositions of the present disclosure. In certain embodiments, the pH of the aqueous fluid may be adjusted (e.g., by a buffer or other pH adjusting agent) to a specific level, which may depend on, among other factors, the types of viscosifying agents, acids, and other additives included in the fluid. One of ordinary skill in the art, with the benefit of this disclosure, will recognize when such density and/or pH adjustments are appropriate.
Examples of non-aqueous fluids suitable for use in certain embodiments of the methods and systems of the present disclosure include, but are not limited to oils, hydrocarbons, organic liquids, and the like. In certain embodiments, the fracturing fluids may comprise a mixture of one or more fluids and/or gases, including but not limited to emulsions, foams, and the like.
Further examples of additional additives include, but are not limited to, salts, surfactants, acids, proppant particulates, diverting agents, fluid loss control additives, gas, nitrogen, carbon dioxide, surface modifying agents, tackifying agents, foamers, corrosion inhibitors, scale inhibitors, catalysts, clay control agents, biocides, friction reducers, antifoam agents, bridging agents, flocculants, additional H₂S scavengers, CO₂scavengers, oxygen scavengers, lubricants, additional viscosifiers, breakers, weighting agents, relative permeability modifiers, resins, wetting agents, coating enhancement agents, filter cake removal agents, antifreeze agents (e.g., ethylene glycol), and the like.
Specific non-limiting examples of corrosion inhibitors include acetylenic alcohols, such as propargyl alcohol organic amines; dimer/trimer acids derived from tall oil or other bases; quaternary amines derived from coconut, canola, tallow, tall oil or other bases; fatty alcohols; derivatized quinolines; alkyl pyridines; and oxyalkylated resin amines.
Anti-foam agents can include, for example, natural or mineral oils, silicone-based agents and/or polydimethylsiloxane (PDMS).
Scale inhibitors can include, for example, phosphonates, polyacrylates, polyphosphates, phosphate esters, chelating agents, polycarboxylic acids, hexametaphosphate and/or tripolyphosphate.
Alternatively, any additives used can be admixed with the package. A person skilled in the art, with the benefit of this disclosure, will recognize the types of additives that may be included in the fluids of the present disclosure for a particular application.
The package can be prepared and then admixed with the sulfur scavenger to make a sulfur scavenger composition or the ingredients for the package can be added in the course of preparing the sulfur scavenger composition. Although the components of the package or the sulfur scavenger composition can be admixed in any order, it is usually preferred to prepare the package prior to contact with the sulfur scavenger. Often, the polyhydroxylated hydrocarbon is admixed with the organic acid as these components generally comprise the majority of the package. The subsequent addition of the hydrocarbyl alcohol may, in some instances, first evidence cloudiness or visible bubbles, it clears overtime after sufficient mixing has stabilized the clusters. The dielectric component is then added. If the package is to contain water, the water may be added at any point. In some instances, it may be desired to prepare a sulfur scavenger concentrate composition that contains the package components and some or all of the sulfur scavenger and then water or additional water is later added to form the scavenger composition for use. Typically, water may be used in the concentrate composition to facilitate the inclusion of the sulfur scavenger and form clusters. With some sulfur scavengers such as triazines, the commercial formulations contain water.
The relative amounts of the polyhydroxylated hydrocarbon, hydrocarbyl alcohol and organic acid are important to achieving the enhanced performance of the sulfur scavenger composition, and the relative amounts can be optimized for the specific sulfur scavenger used by those skilled in the art having the benefit of this disclosure. Again, without intending to be limited by theory, it is believed that maintaining a desirable hydroxyl to hydronium balance in the sulfur scavenger composition enables the formation and maintenance of clusters and increased uptake of sulfhydryl moieties.
Preferred additive packages for triazine sulfur scavengers, preferably containing at least one of MEA triazine and MMA triazine, have:

- a) a mass ratio of the hydrocarbyl alcohol (e.g., 2-ethylhexane or cyclohexane), to the polyhydroxylated hydrocarbon (e.g., at least one of ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol and glycerol), of about, e.g., 1:1 to 1:100, 1:100 to 100:1, 1:40 to 40:1, 1:20 to 30:1, 1:15 to 20:1, or preferably about 1:1 to 20:1, and
- b) a mass ratio of the organic acid (e.g., an amino acid comprising at least two acid groups, such as ethylenediamine tetraacetic acid), to the polyhydroxylated hydrocarbon of about, e.g., 1:1 to 1:100, 1:100 to 100:1, 1:50 to 25:1, 1:30 to 15:1, 1:20 to 10:1, or preferably about 1:5 to 5:1.

In a preferred embodiment, the additive packages comprise a water dispersed, metal-containing, dielectric component, e.g., poly(dimethylsiloxane) homopolymer or copolymer, in a mass ratio to the polyhydroxylated hydrocarbon of between about, e.g., 0.001:1000 to 50:1000, 0.01:1000 to 40:1000, 0.1:1000 to 30:1000, 1:1000 to 25:1000, or preferably, between about 0.05:1000 to 10:1000. The sulfur scavenger according to embodiments of the subject invention can be any suitable amine-containing scavenger containing at least one primary, secondary or tertiary amine. In certain preferred embodiments, the scavengers are triazines, which can be used as the sulfur scavenger or used in combination with other amine-based sulfur scavengers. A number of the triazines useful in the compositions of this invention are commercially available. Commercial triazines often contain components such as water or unreacted amine. Typically, triazines are formed by reacting amines with an aldehyde, especially formaldehyde as is well known in the art. See, for instance U.S. Pat. No. 4,266,054. MEA triazine is a preferred triazine due to its commercial availability and relatively low cost. Examples of other triazines include MMA triazine, MOPA triazine; 1,3,5 (tris-methoxyethyl) hexahydrotriazine; 1,3,5 (tris-methoxybutyl) hexahydrotriazine; 1,3,5 (tris-ethyl) hexahydrotriazine and 1,3,5 (tris-propyl) hexahydrotriazine, and mixtures of two or more triazines. The triazines can include compounds where each R group is the same or different. The preferred triazines have some water solubility. As the ring nitrogen atoms are replaced with sulfur atoms the triazines become less water soluble and may become substantially insoluble in water. Examples of other amines include, but are not limited to, poly(ethylene imine), diethyl amine, triethyl amine, monoethanol amine, diethanol amine, and methyl amine.
The relative amounts of the sulfur scavenger and the package can vary depending upon the nature of the sulfur scavenger and the sought performance for sulfur scavenging prior to cluster collapse. In certain embodiments, the mass ratio (on an anhydrous basis) of the package to sulfur scavenger is in the range of about, e.g., 0.01:1 to 1:1, 0.1:1 to 0.5:1, 0.2:1 to 0.8:1, or about 0.2:1 to 0.35:1.
In certain embodiments, the scavenger composition used for removal of sulfhydryl typically comprises between about, e.g., 1 and 100, 3 and 90, 5 and 85, 10 and 80, or between about 25 to 75, mass percent water.
In preferred embodiments, at least the polyhydroxylated hydrocarbon, hydrocarbyl alcohol and organic acid of the package are admixed prior to the addition of the sulfur scavenger. The admixing is preferably sufficient to provide a clear to the naked eye solution prior to adding the sulfur scavenger.
In additional preferred embodiments, the sulfur scavenger can be added prior to the addition of sufficient water to form the final scavenger composition. Some amine-based scavengers are commercially available in aqueous solutions, and these scavengers are suitable for use in making the sulfur scavenger compositions of this invention. However, in some instances, high shear mixing may be required to optimize the formation of cluster structures.
One preferred type of sulfur scavenger composition according to embodiments of the subject invention comprises at least one of MEA triazine and MMA triazine. In some embodiments, the triazine comprises between about, e.g., 10 to 50, 15 to 40, or 20 to 35 mass percent of the aqueous scavenger composition. In a specific embodiment, the composition further comprises:

- between about 2 and 5 mass percent polyhydroxylated hydrocarbon of 2 to 10 carbons, preferably at least one of ethylene glycol, diethylene glycol, triethylene glycol, and propylene glycol;
- between about 0.1 and 1 mass percent hydrocarbyl alcohol, preferably comprising 2-ethylhexanol;
- between about 0.5 and 2 mass percent organic acid or salt thereof, preferably comprising amino acids having two or more carboxylic or phosphonyl acid groups, and most preferably ethylenediamine tetraacetic acid or salt thereof; and
- between about 0.001 and 0.01 mass percent water-dispersible, metal-containing, dielectric component comprising poly(dimethylsiloxane) homopolymer or copolymer, preferably having a weight average molecular weight between about 500 and 100,000.

Methods

In certain embodiments, the subject invention further provides methods for scavenging sulfhydryl compounds from hydrocarbon streams.
In certain embodiments, the package and/or additives of the subject invention are injected into at least a portion of a subterranean formation, conduit, or container wherein a sulfhydryl compound is present. In certain embodiments, the packages and/or additives react with the sulfhydryl to form nonhazardous and/or noncorrosive products.
The subject methods can be used to directly reduce sulfhydryl content in wells and crude oil and gas and the environments in which oil and gas are produced. The methods can further be used to reduce the “sourness” of crude oil and gas, reduce the conversion of sweet oil and gas to sour oil and gas, increase the conversion of sour oil and gas to sweeter oil and gas, and/or preserve the sweetness of oil and gas.
In certain embodiments, the methods can also be used for reducing and/or eliminating corrosion of equipment and structures used for crude oil and natural gas production through the reduction in acids and sulfhydryl concentration.
In accordance with certain embodiments of the processes of this invention, the scavenger composition is contacted with the hydrocarbon stream containing sulfhydryl moieties, especially hydrogen sulfide.
The contacting can be effected in any convenient manner such as, for example, by injection of the scavenger composition into a process or transport line; passing the hydrocarbon stream such as a natural gas stream through a stirred or non-stirred vessel that contains the scavenger composition; and/or spraying or otherwise introducing the scavenger composition for contact with the hydrocarbon stream.
In some instances, the scavenger composition can be introduced into a well hole. The hydrocarbon stream may contain other components depending upon source. Especially for natural gas streams, nitrogen, carbon dioxide and water are often present an advantage of the compositions of this invention is that the compositions are sufficiently robust to tolerate presence of other components in the hydrocarbon stream while still scavenging sulfhydryl moieties and retarding or avoiding the formation of solids. The hydrocarbon streams to be treated in accordance with this invention may contain up to about, e.g., 5 or more volume percent, often between about, e.g., 10 and 1000, 9 and 900, 8 and 800, 7 and 700, 6 and 600 or 5 and 500 parts per million by volume, sulfhydryl moiety.
In certain embodiments, the duration of the contact between the hydrocarbon stream and the scavenger composition in the scrubber that which is sufficient to provide a treated hydrocarbon stream substantially devoid of hydrogen sulfide, preferably, e.g., less than about 5, less than about 1, less than about 0.1, and most preferably less than about 0.01, parts per million by volume of hydrogen sulfide. In most operations, the scavenger composition is used until an undesired breakthrough of hydrogen sulfide occurs in the treated hydrocarbon stream.
The temperature of the contacting can vary over a wide range and will often be determined by the temperature of the environment and the incoming hydrocarbon stream to be treated. In certain embodiments, the temperature is generally in the range of about, e.g., −10° C. to 150° C., about 0° C. to 125° C., or about 10° C. to 100° C.
In certain embodiments, the method of the subject invention includes introduction of a treatment fluid into a subterranean formation and/or a well bore that penetrates a subterranean formation. Treatment fluids can be used in a variety of subterranean treatment operations. As used herein, the terms “treat,” “treatment,” “treating,” and grammatical equivalents thereof refer to any subterranean operation that uses a fluid in conjunction with achieving a desired function and/or for a desired purpose. Use of these terms does not imply any particular action by the treatment fluid. Illustrative treatment operations can include, for example, fracturing operations, gravel packing operations, acidizing operations, scale dissolution and removal, consolidation operations, and the like.
In certain embodiments, sulfur scavenging compositions and/or additives of the subject invention may be introduced into a subterranean formation, a well bore penetrating a subterranean formation, tubing (e.g., pipeline), and/or a container using any method or equipment known in the art. Introduction of the sulfur scavenging compositions and/or additives may include delivery via any of a tube, umbilical, pump, gravity, and combinations thereof. Additives, treatment fluids, or related compounds of the subject invention may, in various embodiments, be delivered downhole (e.g., into the well bore) or into top-side flowlines/pipelines or surface treating equipment.
For example, in certain embodiments, the subject compositions and/or additives may be applied to a subterranean formation and/or well bore using batch treatments, squeeze treatments, continuous treatments, and/or combinations thereof. In certain embodiments, a batch treatment may be performed in a subterranean formation by stopping production from the well and pumping a specific amount or quantity of the compositions and/or additives, which may be performed at one or more points in time during the life of a well. In other embodiments, a squeeze treatment may be performed by dissolving the compositions and/or additives in a suitable solvent at a suitable concentration and squeezing that solvent carrying the compositions and/or additives downhole into the formation, allowing production out of the formation to bring the compositions and/or additives to the desired location. In certain embodiments, the sulfhydryl is present in a gaseous phase and the compositions and/or additives may be injected as a mist. In other embodiments, the sulfhydryl is present in a gaseous phase and the subject compositions and/or additives may be injected as a liquid, such that the gaseous phase bubbles through them in a tower.
In still other embodiments, treatment fluids and/or additives of the present disclosure may be injected into a portion of a subterranean formation using an annular space or capillary injection system to continuously introduce the compositions and/or additives into the formation. Other means and/or equipment that may be used to continuously inject the compositions and/or additives into a well bore include, but are not limited to slip-stream systems, annulus drip systems, cap strings, umbilical strings, gas lift systems, continuous metering systems, subsurface hydraulic systems, bypass feeders, and the like.
In certain embodiments, continuous injection equipment at a well site may be controlled from a remote location and/or may be partially or completely automated. In certain embodiments, a treatment fluid comprising a composition and/or additive of the subject invention may be circulated in the well bore using the same types of pumping systems and equipment at the surface that are used to introduce treatment fluids or additives into a well bore penetrating at least a portion of the subterranean formation. In certain embodiments, the composition and/or additive could be dried and formed into a solid for delivery into rat holes, tanks, and/or a well bore.
In certain embodiments, the subject compositions and/or additives may be added to a pipeline where one or more fluids enter the pipeline at one or more other locations along the length of the pipeline. In these embodiments, the subject compositions and/or additives may be added in batches or injected substantially continuously while the pipeline is being used.
In some embodiments, the components of the compositions and/or additives are not mixed until they are injected into the subterranean formation, conduit, or container. In certain embodiments, the compositions and/or additives are mixed shortly before they are injected. In other embodiments, a spacer is used to keep the components of the compositions and/or additives from mixing until they reach a particular portion of a subterranean formation, conduit, or container.
The sulfur scavenging compositions and/or additives of the subject invention can be used in a variety of applications. These include downhole applications (e.g., drilling, fracturing, completions, oil production), use in conduits, containers, and/or other portions of refining applications, gas separation towers/applications, pipeline treatments, water disposal and/or treatments, and sewage disposal and/or treatments.
The present disclosure in some embodiments provides methods for using the additives, treatment fluids, and related compounds to carry out a variety of subterranean treatments, including but not limited to, hydraulic fracturing treatments, acidizing treatments, and drilling operations.

Example 1

A composition of the subject invention (Composition A) was compared to a well-known and previously-studied amine-based H₂S scavenger: MEA triazine (1,3,5-(tris-hydroxyethyl) triazine).
There are three key performance characteristics that establish the proficiency of an H₂S scavenger in removing sulfhydryl moieties from hydrocarbon streams. The first performance parameter is stochiometric capacity to absorb sulfur, also known as the total sulfur uptake capacity. The second parameter is reaction kinetics, which is the speed at which the H₂S scavenger's uptake capacity can absorb, or react-out, sulfhydryl moieties from the hydrocarbon stream. The third parameter is the H₂S scavenger's propensity to prevent solids deposition of the scavengers by-products, or providing a higher tolerance towards the mitigation of such deposition.
These three performance parameters can be expressed as the equation: Ax (Total Uptake Capacity)+Bx (Reaction Kinetics)+Cx (Solids Mitigation)=Dx (Increased Scavenger Performance).

- Composition A (percentages are by volume):
- 0.56% 2 Ethyl Hexanol;
- 6.00% glycerol;
- 0.625% EDTA;
- 0.04% poly dimethyl siloxane;
- 25% MEA Triazine; and
- Balance is distilled water.

MEA triazine was selected to compare with Composition A because its performance attributes are well understood, and it is the most widely applied technology across all industry platforms to remove sulfhydryl moieties from hydrocarbon streams.
The sulfhydryl moieties used for this evaluation were obtained from Air Gas and contained a certified gas composition containing 50,000 ppm hydrogen sulfide, and 100,000 ppm carbon dioxide, with the remaining composition being nitrogen. Carbon dioxide was selected because most hydrocarbon streams contain various concentrations of this gas with sulfhydryl moieties, and certain H₂S scavenger technologies performance can be adversely affected by the presence of carbon dioxide.
An air pump was used to dilute the gas composition stream to demonstrate performance characteristics associated with reaction kinetics from various sulfhydryl moieties gas stream concentrations.
All performance test runs comparing Composition A to MEA triazine were run under the same set of conditions using the same equipment configuration.
Flow rates were set at a static 0.65 standard cubic feet per hour (SCFH) or 0.3 liters per minute. 50 milliliters of chemistry is used to establish a small liquid contact bed within a miniature contact tower containing a gas sparge. The contact tower has a total volumetric capacity of 250 milliliters. The gas was sparged through the contact fluid (scavenger medium) and directly exited via a small tube to an AMI model 3000 rs autonomous H₂S analyzer that pulls breakthrough H₂S concentrations ˜minute. Calibrated gas of ˜25 ppm H₂S was passed through the detector before each test run to verify sensor accuracy before performance evaluations.
FIG. 1 is a depiction of the test setup used to evaluate sulfur loading and reaction kinetics.

Total Sulfur Uptake Capacity (Ax)

Each test run began with a calibration check proceeding the test. Once the H₂S breakthrough exceeded the sensor range, H₂S (lead acetate) tubes were manually pulled to verify that the H₂S scavenger was no longer actively scavenging. The subsequent spent scavenger fluid was measured before and after for density changes. Sulfur content was measured with both FT-IR (Fourier Transform InfraRed) spectrophotometry and XRF (X-Ray Fluoresce) to determine the amount of absorbed sulfur. The run times ranged from 8-12 hours.
Table 1 provides a summary of the total sulfur contents. The results demonstrate that even though Composition A has a much lower amine concentration, the capacity performed similarly to MEA triazine.

TABLE 1

				Measured	Calculated	Uptake
		Density of		total uptake	Uptake before	Improvement
%		Unreacted		via FTIR and	Sensor over-	based on
Active	Product	Chemistry	Measured	XRF (sulfur	range (sulfur	measured %
Amine	Name	(lbs/gal)	% Sulfur	lbs/gal)	lbs/gal)	sulfur

25%	Composition A used	8.90	13.98%	1.24	1.05	36.5%
	with MEA-Triazine
40%	40% 1,3,5	9.01	14.03%	1.26	1.23
	MEA-Triazine
35%	35% 1,3,5	8.92	12.29%	1.10	1.09
	MEA-Triazine

25%	1,3,5 MEA-Triazine Calculated	0.79

Reaction Kinetics (Bx)

Each test run began with a calibration check proceeding the test. The test runs reflect two types of test stress conditions. The first test run was performed under ultra-high H₂S saturation conditions (5% or 50,000 ppm). The second set of test runs were designed to demonstrate the effects of higher gas temperatures by pre-heating the liquid medium to 120 F and passing the sulfhydryl moieties through the liquid contact scavenger bed that was heated to 120 F throughout the duration of the test.
This test was designed to differentiate the effects of either the volatility of the scavenger and/or by creating a heated liquid interphase, the reduced apparent viscosity would reduce the contact time of the gas within the bed due to lower interfacial tension between two substrates (in this case liquid to gas). All test runs were run at the aforementioned 0.65 SCFH or 0.3 liters per minute.
Of important note to the evaluation of reaction kinetics is that most pipeline shipping specifications from midstream companies require oil and gas operators/producers to maintain a hydrogen sulfide concentration below 10 ppm.
On the high H₂S profile containing 50,000 ppm hydrogen sulfide, the Composition A maintained an H₂S breakthrough PPM below 10 ppm for an average of 141 minutes with an average H₂S breakthrough of just 5.86 ppm.
35% MEA triazine eclipsed the 10 ppm threshold in as little as 2 minutes with an average H₂S breakthrough of 150 ppm in the same respective time frame (141 minutes).
40% MEA triazine eclipsed the 10 ppm threshold in as little as 2 minutes with an average H₂S breakthrough of 109 ppm in the same respective time frame (141 minutes).
This demonstrates a minimum factor of 18× lower H₂S breakthrough concentration for Composition A. This reduces the contact time needed and significantly widens the application options.
On the lower H₂S profile containing 2.500 ppm hydrogen sulfide with simulated higher thermal profile temperatures, Composition A maintained an H₂S breakthrough PPM below 10 ppm for the duration of the 180-minute test run with an average H₂S breakthrough of just 4.79 ppm. This demonstrates the resilience of the technology under higher thermally simulated conditions.
35% MEA triazine eclipsed the 10 ppm threshold in as little as 14 minutes with an average H₂S breakthrough of 15.75 ppm in the same respective time frame (180 minutes).
This demonstrates a minimum factor of 3× lower H₂S breakthrough ppm concentration for Composition A with a 166 minute longer runtime below pipeline specifications.

Solids Mitigation (Cx)

One common drawback to MEA triazine is the propensity to form solids. Those solids can best be described as amorphous di thiazine, also known as poly sulfides.
Advantageously, the compositions of the current invention reduce solids formation. The multimolecular formation of clusters exhibits a unique interchange at the interface of the molecules, wherein an exchange takes place with the sulfhydryl moieties that inhibits the formation of longer chain polysulfides.
Another unique aspect of the subject invention, is that the formula can be adjusted to maintain the clusters indefinitely or designed to phase separate once the scavenger is spent. This allows for the cluster to be formulated such that the cluster breaks rapidly once the scavenger is spent, separating into two distinct phases. This allows for a liquid bottom phase containing the sulfur to be recovered, should that attribute be desired for recycling and/or repurposing of sulfur rich fluids.

Increased Scavenger Performance Summary (Dx)

A high performing H₂S scavenger can be represented by the following equation: Ax (Total Uptake Capacity)+Bx (Reaction Kinetics)+Cx (Solids Mitigation)=Dx (Increased Scavenger Performance). With 36.5% higher total uptake capacity then the amine's designed capacity would traditionally allow, reaction kinetics ranging from 3× to 18× less breakthrough H₂S ppm, the tested embodiment forming clusters that prevent solids from precipitate and having the ability to specifically formulate for the allowed ease of recovering sulfur for recycling purposes, the compositions and methods of the subject invention have obtained all three key performance criteria for exhibiting the advantages of this technology.
As discussed above, the sulfur scavenger compositions of this invention can be designed such that the cluster structure remains stable upon the sulfur scavenger becoming spent or designed such that the cluster structure collapses as the sulfur scavenger becomes spent. In some instances, maintaining the cluster structure enables a liquid solution relative free of solids to be withdrawn and disposed of. In other instances, especially where the scavenged sulfur is intended to be sent to a refinery, the collapse of the cluster structure is desired. Generally, and especially with triazine sulfur scavengers, the sulfur scavenger upon cluster structure collapse, forms a heavier, water-immiscible, liquid phase that can be recovered for shipment to a refinery. As the processes attenuate the formation of solids, the separation, recovery and shipping can be accomplished without undue solids deposits forming.

Claims

I claim:

1. A sulfhydryl scavenger performance-enhancing additive comprising:

a) polyhydroxylated hydrocarbon of at least one of 2 to about 10 carbons and hydroxy-terminated, poly(alkylene oxide) having a weight average molecular weight of up to about 20,000;

b) hydrocarbyl alcohol having a terminal hydroxy group, about 5 to 24 carbons, at least one of which is a tertiary carbon; and

c) organic acid or salt thereof having at least one carboxyl or phosphonyl substituent;

wherein the hydrocarbyl alcohol is provided in said composition to provide a mole ratio of hydroxyls in the hydrocarbyl alcohol per hydroxyl of the polyhydroxylated hydrocarbon of between about 1:100 to 50:100; and the organic acid or salt thereof is provided in said composition to provide a mole ratio of acid moieties per hydroxyl of the polyhydroxylated hydrocarbon of between about 5:100 to 25:100.

2. The additive of claim 1, further comprising a water-soluble, polymeric dielectric component in a mass ratio to the polyhydroxylated hydrocarbon of between about 0.01:1000 to 20:1000.

3. The additive of claim 1, wherein the polyhydroxylated hydrocarbon comprises at least one of ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol and glycerol.

4. The additive of claim 3, wherein the hydrocarbyl alcohol comprises at least one of 2-ethylhexanol and cyclohexanol.

5. The additive of claim 1, wherein the organic acid or salt thereof comprises ethylenediamine tetraacetic acid or salt thereof.

6. The additive of claim 1, wherein the additive further comprises triazine.

7. The additive package of claim 1, for use with triazine sulfur scavengers having:

a mass ratio of the hydrocarbyl alcohol comprising 2-ethylhexane or cyclohexane to the polyhydroxylated hydrocarbon comprising at least one of ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol and glycerol, of about 1:1 to 20:1, and

a mass ratio of an organic acid comprising an amino acid having at least two acid groups, to the polyhydroxylated hydrocarbon of about 1:5 to 5:1.

8. The additive package of claim 7, further comprising a water dispersed, metal-containing, dielectric component, comprising poly(dimethylsiloxane) homopolymer or copolymer, in a mass ratio to the polyhydroxylated hydrocarbon of between about 0.05:1000 to 10:1000.

9. A sulfhydryl scavenger composition comprising at least one amine-based sulfur scavenger and between about 0.05 to 1 part by mass of the additive of claim 1 (on an anhydrous basis) provided per part by mass of the amine-based sulfur scavenger (on an anhydrous basis).

10. The scavenger composition of claim 9, wherein the sulfur scavenger comprises at least one of MMA triazine and MEA triazine.

11. The scavenger composition of claim 10, wherein the mass ratio of said additive to sulfur scavenger is in the range of about 0.1:1 to 0.5:1.

12. The scavenger composition of claim 9, further comprising a water dispersed, metal-containing, dielectric component, comprising a poly(dimethylsiloxane) homopolymer or copolymer, in a mass ratio to the polyhydroxylated hydrocarbon of between about 0.05:1000 to 10:1000.

13. An aqueous sulfur scavenger composition comprising at least one of MEA triazine and MMA triazine, and further comprising

between about 2 and 5 mass percent polyhydroxylated hydrocarbon of 2 to 10 carbons;

between about 0.1 and 1 mass percent hydrocarbyl alcohol;

between about 0.5 and 2 mass percent organic acid or salt thereof; and

between about 0.001 and 0.01 mass percent water-dispersible, metal-containing, dielectric component comprising poly(dimethylsiloxane) homopolymer or copolymer, preferably having a weight average molecular weight between about 500 and 100,000.

14. The composition of claim 13, wherein the polyhydroxylated hydrocarbon comprises at least one of ethylene glycol, diethylene glycol, triethylene glycol, and propylene glycol.

15. The composition of claim 14, wherein the hydrocarbyl alcohol comprises at least one of 2-ethylhexanol and cyclohexanol.

16. The composition of claim 13, wherein the organic acid or salt thereof comprises an amino acid or salt thereof having two or more carboxylic or phosphonyl acid groups.

17. The composition of claim 16, wherein the organic acid or salt thereof comprises ethylenediamine tetraacetic acid or salt thereof.

18. The composition of claim 13, further comprising a water dispersed, metal-containing, dielectric component, comprising a poly(dimethylsiloxane) homopolymer or copolymer, in a mass ratio to the polyhydroxylated hydrocarbon of between about 0.05:1000 to 10:1000.

19. A process for reducing an amount of sulfhydryl moieties in a hydrocarbon stream comprising contacting in the presence of water said hydrocarbon stream with a composition of claim 10.

20. A process for reducing an amount of sulfhydryl moieties in a hydrocarbon stream comprising contacting in the presence of water said hydrocarbon stream with a composition of claim 13.