Antifouling compositions and methods of reducing fouling in petroleum process streams

Abstract

The invention discloses an anti-fouling composition and a method of reducing fouling in a petroleum process stream, the method comprising reacting a precursor polymer with a primary amine to form a dispersant polymer; combining one or more dispersant polymers with one or more inhibitors to form an anti-fouling composition; combining the anti-fouling composition with a petroleum product to form a treated petroleum product; and applying the treated petroleum product to a petroleum processing apparatus to form a treated petroleum process stream. Also disclosed is the use of the dispersant polymer in a method of increasing the induction period of a functionalized p-phenylenediamine inhibitor in a petroleum process stream. The concentrate of the anti-fouling composition in solvent is stable and pourable at a temperature of 0 DEG C to-40 DEG C. The anti-fouling composition is added to a petroleum product to form a treated petroleum product that reduces fouling and forms a stable dispersion over a wide range of processing conditions.

Description

[0001] This application is a divisional application of an invention patent application with an application date of December 6, 2017, application number "201780074436.7", and invention name "Anti-scaling composition for petroleum process streams". Technical Field

[0002] The present invention relates to blends of polymeric dispersants with amino-functional inhibitors of petroleum products, and uses thereof. Background Art

[0003] Hydrocarbon processing plants, from refineries to petrochemical plants, suffer from fouling due to the deposition of hydrocarbon by-products in heat exchangers, furnaces, water circulation loops, distillation columns, vessels, pipelines, overheads, and other processing equipment. These by-products include various hydrocarbons that may be present in crude oil as well as by-products of hydrocarbon refining processes. Fouling of the internal surfaces of processing equipment occurs over a period of time that can range from a few months to a few years, depending on the unit under consideration.

[0004] It is believed that asphaltenes (dirts present in crude oil sources prior to human extraction or collection) exist as colloidal dispersions stabilized by other components of crude oil. These naturally occurring dirts can be destabilized by various mechanical, thermal, and chemical conditions involved in oil production and processing. Other dirts are produced by polymerization or other reactions of vinyl byproducts of oil processing such as styrene, butadiene, cyclopentadiene, etc.; oxidized hydrocarbons; and thermal decomposition products produced by degradation of larger molecules (such as one of the dirts listed above), either alone or in combination with one or more other compounds present in the oil source. Such dirts may be referred to as "synthetic dirts" because they are produced by human operations undertaken to process crude oil; while asphaltenes may be referred to as "natural dirts" because these are present in crude oil sources obtained from underground reservoirs.

[0005] Hydrotreating is a traditional petroleum process that provides an illustrative example of how synthetic fouling is produced. Hydrotreating is a catalytic hydrogenation process that results in the conversion of nitrogen and sulfur-containing contaminants to hydrogen sulfide and ammonia. It is also used to convert aromatics and olefins to saturates. The thermal and oxidative conditions during hydrotreating can lead to the formation of synthetic fouling. Fouling formed or synthesized during such processes adheres to processing equipment surfaces, such as preheat exchangers, resulting in reduced unit throughput and pressure drop through the heat exchanger tubes.

[0006] Both natural and synthetic foulants are of concern to hydrocarbon processing plant operators because, regardless of their source, the accumulation and precipitation of foulants on any one or more surfaces within processing equipment or storage vessels can lead to a number of operator problems. Such problems include flow restrictions and loss of sensitivity of measuring equipment such as thermocouples in the subject process stream. The need to remove foulants from the interior surfaces of petroleum processing equipment is a significant cause of plant downtime. Therefore, there is a continuing need for new methods and compositions to address the fouling problem.

[0007] While natural foulants can be addressed by dispersants, some synthetic foulants can be prevented from forming entirely. For example, the addition of an oil-soluble free radical inhibitor (also known as an antioxidant) to the hydrotreating process stream described above can reduce the observed fouling, likely due to the slowing or termination of certain synthetic pathways that form synthetic foulants associated with the characteristics of that process stream.

[0008] Comer et al., U.S. Pat. No. 5,214,224, discloses olefin-maleic anhydride copolymers that can be used as dispersants for scale in liquid petroleum process streams. However, these anhydride functional polymers are reactive to hydrolysis conditions, undergoing ring-opening addition of water to the anhydride functional groups. The hydrolyzed polymers are not scale resistant and can themselves become scale due to low solubility. Therefore, anhydride functional polymers are not suitable for use in process streams contaminated with water. In addition, the hydrolysis of the anhydride functional groups can proceed slowly over time, even in substantially dry petroleum products, where water is an impurity of the petroleum product.

[0009] In addition, olefin-maleic anhydride copolymers - and their hydrolysis byproducts - tend to precipitate out of concentrates (in the form of concentrates in which the polymers are sold) or form viscous, even solidified, admixtures with solvents at low temperatures encountered on site during winter oil processing operations (which can easily reach 0°C to -40°C). This is because olefin-maleic anhydride copolymers are insoluble or only slightly soluble in petroleum-based solvents even at temperatures of about 20°C; at lower temperatures, instabilities arise, making it difficult to pump, pour or otherwise transport the polymer-solvent combination on site, for example, in winter.

[0010] This instability further affects petroleum process streams, where a combination of dispersants and inhibitors is specified. In order to use olefin-maleic anhydride copolymers as dispersants together with oil-soluble inhibitors, two separate additions are usually required, rather than adding a blend of the two materials to the petroleum process stream. This is because olefin-maleic anhydride copolymers - and their hydrolysis byproducts - are insoluble or only slightly soluble in liquid petroleum products or in the petroleum-based solvents used to deliver the oil-soluble inhibitors to the petroleum process stream. Since some petroleum processing equipment only includes a single port for, for example, introducing additives into the petroleum process stream, olefin-maleic anhydride copolymers, while effective as dispersants in such systems, are not optimal for use due to solubility issues.

[0011] There is a need to prevent fouling in petroleum process streams due to natural and synthetic foulants. There is a need for a combination that can achieve the above objectives by applying a single composition including a dispersant and an inhibitor to a petroleum process stream. There is also a need to provide a concentrate of an antifouling composition that is a stable dispersion at temperatures of about 0°C to -40°C and is pumpable or pourable. Summary of the invention

[0012] Disclosed herein are antifouling compositions comprising or consisting essentially of a combination of one or more dispersant polymers comprising, consisting essentially of, or consisting of polymerized residues of one or more alpha-olefins and maleic anhydride, further wherein 80 mol % to 100 mol % of the maleic anhydride residues are reacted with a primary amine defined by the formula R-NH2, wherein R is a linear or branched hydrocarbon moiety containing from 6 to 30 carbon atoms or a mixture of two or more such moieties; and one or more inhibitors comprising, consisting essentially of, or consisting of a functionalized p-phenylenediamine (fPDA) defined by the formula

[0013]

[0014] Wherein R' is independently selected as a linear, branched, aromatic or alicyclic moiety comprising 1 to 12 carbon atoms, optionally including one or more O, S, N or halogen atoms, provided that the fPDA does not include a primary amine moiety. The ratio of the one or more dispersant polymers to the one or more inhibitors in the composition is about 10:1 to 1:10 by weight, and in some embodiments is about 1:3 to 3:1 by weight. In an embodiment, the dispersant polymer is characterized by the substantial absence of anhydride or imide moieties. In an embodiment, the dispersant polymer is characterized by the substantial absence of anhydride and imide moieties. The antifouling composition is soluble in liquid petroleum products or liquid petroleum process streams and non-polar solvents conventionally used to introduce compounds into petroleum process streams; non-polar solvents are liquids having a dielectric constant of less than 15 and blends of such liquids.

[0015] In embodiments, the anti-fouling composition is an anti-fouling concentrate comprising, consisting essentially of, or consisting of a combination of one or more dispersant polymers as described above, one or more inhibitors as described above, and a solvent, wherein the one or more dispersant polymers and the one or more inhibitors are present in a combined total amount of about 15 wt % to 90 wt % in the solvent, and the concentrate is pumpable or pourable at a temperature between about 0° C. and -40° C. In embodiments, the dielectric constant of the solvent is 15 or less.

[0016] Also disclosed herein is a treated petroleum product comprising, consisting essentially of, or consisting of a petroleum product and 1 ppm to 1000 ppm of an antifouling composition comprising, consisting essentially of, or consisting of a combination of one or more dispersant polymers and one or more inhibitors, the one or more dispersant polymers comprising, consisting essentially of, or consisting of polymerized residues of one or more alpha-olefins and maleic anhydride, further wherein 80 mol % to 100 mol % of the maleic anhydride residues are reacted with a primary amine defined by the formula R-NH2, wherein R is a linear or branched hydrocarbon moiety containing from 6 to 30 carbon atoms or a mixture of two or more such moieties; and the inhibitor comprises, consists essentially of, or consists of a functionalized p-phenylenediamine (fPDA) defined by the formula

[0017]

[0018] Wherein R' is independently selected as a straight chain, branched chain, aromatic or alicyclic moiety, which contains 1 to 12 carbon atoms, optionally including one or more O, S, N or halogen atoms, provided that the fPDA does not include a primary amine moiety. The ratio of the one or more dispersant polymers to the one or more inhibitors in the treated petroleum product is about 10:1 to 1:10 by weight, and in some embodiments is about 1:3 to 3:1 by weight. In an embodiment, the treated petroleum product is a treated liquid petroleum product. The treated liquid petroleum product is a stable dispersion between about 20°C and 400°C, wherein the dispersant polymer is thermally stable and reduces or prevents fouling caused by natural and / or synthetic fouling in the treated liquid petroleum product during one or more petroleum processing operations such as hydroprocessing. In addition, the dispersant polymer is hydrolytically stable and is thus suitable for inclusion in concentrates, petroleum products and petroleum process streams contaminated with water (e.g., about 1% by weight or less water).

[0019] In some embodiments, the treated petroleum product is a treated petroleum process stream. The treated petroleum process stream causes a 50% to 100% reduction in fouling of the petroleum processing equipment in a first time period compared to the fouling of the petroleum process stream (i.e., an untreated petroleum process stream) in the same time period. In some embodiments, the treated petroleum process stream and product are stable dispersions, further wherein the dispersion stability is maintained during one or more petroleum processing operations, in one or more petroleum process streams, during handling of the composition in one or more petroleum processing units, and during transportation and storage of the treated petroleum product.

[0020] Also disclosed herein is a method of reducing fouling in one or more petroleum process streams, the method comprising, consisting essentially of, or consisting of the following steps: a) combining one or more dispersant polymers and one or more inhibitors in a weight ratio of about 1:10 to 10:1 to form an antifouling composition, wherein the one or more dispersant polymers comprise, consist essentially of, or consist of polymerized residues of one or more alpha-olefins and maleic anhydride, further wherein 80 mol% to 100 mol% of the maleic anhydride residues are reacted with a primary amine defined by the formula R-NH2, wherein R is a linear or branched hydrocarbon moiety containing 6 to 30 carbon atoms or a mixture of two or more such moieties; and the inhibitor comprises, consists essentially of, or consists of a functionalized p-phenylenediamine (fPDA) defined by the formula

[0021]

[0022] Wherein R' is independently selected as a linear, branched, aromatic or alicyclic moiety containing 1 to 12 carbon atoms, optionally including one or more O, S, N or halogen atoms, provided that the fPDA does not include a primary amine moiety, and b) applying about 1 ppm to 1000 ppm by weight or about 1 ppm to 1000 ppm by volume of the anti-fouling composition to a petroleum process stream to form a treated petroleum process stream. In an embodiment, the anti-fouling composition is added to the petroleum process stream before the petroleum product is placed in the petroleum processing equipment; in other embodiments, the anti-fouling composition is added directly to the petroleum process stream while the petroleum process stream is placed in the petroleum processing equipment. In an embodiment, the method also includes subjecting the treated petroleum process stream to a temperature of about 20°C to 400°C, further wherein the treated petroleum process stream is a stable dispersion, and / or wherein the treated petroleum process stream exhibits anti-fouling properties during the process. In some such embodiments, the process is hydroprocessing.

[0023] This application includes the following implementation plans:

[0024] Embodiment 1. An antifouling composition comprising one or more dispersant polymers and one or more inhibitors, wherein the one or more dispersant polymers comprise polymerized residues of one or more alpha-olefins and maleic anhydride, further wherein 80 mol% to 100 mol% of the maleic anhydride residues are reacted with a primary amine defined by the formula R-NH2, wherein R is a linear or branched hydrocarbon moiety containing 6 to 30 carbon atoms or a mixture of two or more such moieties; and the one or more inhibitors comprise a functionalized p-phenylenediamine defined by the formula

[0025] [1]

[0026] wherein R' is independently selected to be a linear, branched, aromatic or alicyclic moiety comprising from 1 to 12 carbon atoms, optionally including one or more O, S, N or halogen atoms, provided that the functionalized p-phenylenediamine does not include a primary amine moiety.

[0027] Embodiment 2. The composition of embodiment 1, wherein the one or more dispersant polymers are characterized by the substantial absence of anhydride moieties, imide moieties, or both anhydride and imide moieties.

[0028] Embodiment 3. The composition of embodiment 1 or 2, wherein the ratio of the one or more dispersant polymers to the one or more inhibitors in the antifouling composition is from about 10:1 to 1:10 by weight.

[0029] Embodiment 4. A concentrate comprising a solvent and about 15% to 90% by weight of the antifouling agent composition of any one of embodiments 1-3.

[0030] Embodiment 5. The concentrate of embodiment 4, characterized in that it is stable and pumpable or pourable at a temperature between about 0°C and -40°C.

[0031] Embodiment 6. A treated petroleum product comprising a petroleum product and about 1 ppm to 1000 ppm of the antifouling composition of any one of embodiments 1-5.

[0032] Embodiment 7. The treated petroleum product of Embodiment 6, wherein the product is present at a temperature between about 20°C and 400°C and is characterized as a stable dispersion.

[0033] Embodiment 8. A treated petroleum product according to Embodiment 6 or 7, wherein the treated petroleum product is a treated petroleum process stream.

[0034] Embodiment 9. A method for reducing fouling in one or more petroleum process streams, the method comprising

[0035] adding from about 1 ppm to 1000 ppm by weight of the anti-fouling composition to the petroleum product to form a treated petroleum product; and

[0036] applying the treated petroleum product to a petroleum processing facility to form a treated petroleum process stream,

[0037] wherein the antifouling composition comprises one or more dispersant polymers and one or more inhibitors, wherein the one or more dispersant polymers comprise polymerized residues of one or more alpha-olefins and maleic anhydride, further wherein 80 mol % to 100 mol % of the maleic anhydride residues are reacted with a primary amine defined by the formula R-NH2, wherein R is a linear or branched hydrocarbon moiety containing from 6 to 30 carbon atoms or a mixture of two or more such moieties; and the one or more inhibitors comprise a functionalized p-phenylenediamine defined by the formula

[0038] [2]

[0039] wherein R' is independently selected to be a linear, branched, aromatic or alicyclic moiety comprising from 1 to 12 carbon atoms, optionally including one or more O, S, N or halogen atoms, provided that the functionalized p-phenylenediamine does not include a primary amine moiety.

[0040] Embodiment 10. The method according to embodiment 9, wherein the adding of the antifouling composition is performed before applying the treated petroleum product to the petroleum processing equipment.

[0041] Embodiment 11. The method according to embodiment 9, wherein the adding of the antifouling composition is directly added to the petroleum processing equipment while the petroleum process stream is placed in the petroleum processing equipment.

[0042] Embodiment 12. The method of any one of Embodiments 9-11, wherein the method further comprises subjecting the treated petroleum process stream to a temperature of about 20°C to 400°C.

[0043] Embodiment 13. A method according to Embodiment 12, wherein the subjecting is hydrotreating.

[0044] Embodiment 14. Use of an antifouling composition for reducing fouling in a petroleum process stream, the antifouling composition comprising one or more dispersant polymers and one or more inhibitors, wherein the one or more dispersant polymers comprise polymerized residues of one or more alpha-olefins and maleic anhydride, further wherein 80 mol % to 100 mol % of the maleic anhydride residues are reacted with a primary amine defined by the formula R-NH2, wherein R is a linear or branched hydrocarbon moiety comprising 6 to 30 carbon atoms or a mixture of two or more such moieties; and the one or more inhibitors comprise a functionalized p-phenylenediamine defined by the formula

[0045] [3]

[0046] wherein R' is independently selected to be a linear, branched, aromatic or alicyclic moiety comprising from 1 to 12 carbon atoms, optionally including one or more O, S, N or halogen atoms, provided that the functionalized p-phenylenediamine does not include a primary amine moiety.

[0047] Embodiment 15. The use according to embodiment 14, wherein the one or more antifouling compositions are used in a total amount of 1 ppm to 1000 ppm based on the weight of the petroleum process stream. DETAILED DESCRIPTION

[0048] Although the present disclosure provides references to preferred embodiments, those skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the present invention. Reference to various embodiments does not limit the scope of the appended claims. In addition, any examples set forth in this specification are not intended to limit and merely set forth some of the many possible embodiments of the appended claims.

[0049] Additional advantages and novel features of the invention will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following or may be learned by routine experimentation in practicing the invention.

[0050] definition

[0051] As used herein, the term "fouling" refers to phase separation by precipitation from a petroleum product wherein the precipitant contacts and adheres to one or more internal surfaces of petroleum processing equipment.

[0052] As used herein, the term "foulant" refers to any one or more substances present in a petroleum product and capable of being precipitated therefrom. As determined by the context, the foulant includes one or more natural foulants, one or more synthetic foulants, or a combination thereof. In embodiments, the one or more foulants are present dispersed within the liquid petroleum product; in some such embodiments, the dispersion is a colloidal dispersion.

[0053] As used herein, the term "natural foulant" means any one or more fouling materials inherently present in crude oil. In an embodiment, natural foulants include asphaltenes, heavy oils, tars, and aliphatic and aromatic hydrocarbons with a density less than water (commonly referred to as light oils).

[0054] As used herein, the term "synthetic foulant" refers to any one or more fouling materials that are byproducts of the petroleum refining process. In various embodiments, the synthetic foulant may include any one or more of the following: polynuclear aromatic hydrocarbons, coke, oxygenated hydrocarbons, polymers formed by polymerizing vinyl byproducts of petroleum processing such as styrene, butadiene, cyclopentadiene, and thermal decomposition products resulting from the degradation of larger molecules (such as one of the foulants listed above), and combinations of these.

[0055] As used herein, the term "petroleum product" and similar terms mean any hydrocarbon product obtained from an underground reservoir, any product derived therefrom, or any mixture thereof. Non-limiting examples of petroleum products include, but are not limited to, crude oil, crude oil after distillation, crude oil fractions, heavy oil or asphalt, hydrogenated oil, refined oil, by-products of petroleum product processing (such as pyrolysis, hydrotreating or phase separation), or a mixture of two or more of these.

[0056] As used herein, the term "liquid petroleum product" and like terms refer to a petroleum product that is substantially liquid at 20°C.

[0057] As used herein, the term "petroleum process stream" and similar terms refer to any petroleum product placed in fluid contact with the internal surface of a petroleum processing device, wherein the process stream includes one or more soils, i.e., one or more natural soils, one or more synthetic soils, or a mixture of two or more thereof. The process stream can be substantially static, such as a petroleum product placed in a settler (separator) or storage container for a selected contact time, such as up to two years. The process stream can be substantially dynamic, such as a liquid petroleum product placed in a pipe during the transportation of the product from a first location to a second location. In some embodiments, the process stream includes one or more other components related to petroleum processing; these components are not particularly limited.

[0058] As used herein, the terms "petroleum processing equipment," "petroleum processing unit," and similar terms mean a man-made article having an interior surface comprising metal, wherein one or more petroleum products are in contact with a metallic fluid for any period of time at any temperature as further determined by the context. Petroleum processing equipment includes articles used to remove petroleum products from underground reservoirs, to transport one or more petroleum products from a first location to a second location, or to separate, refine, process, separate, distill, react, meter, heat, cool, or contain one or more petroleum products.

[0059] As used herein, the terms "pumpable," "pumpable," "pourable," "pourable," or similar terms refer to the "pour point" according to ASTM D-97A as determined by the context, or alternatively refer to a petroleum product having a sufficiently low viscosity to be pumped or poured using conventional oil gathering, refining, transportation, and storage equipment. The test set forth in ASTM D-97A includes a procedure of decreasing the temperature of the composition at 3°C / minute, and the temperature at which no movement of the concentrate is observed is referred to as the pour point of the composition.

[0060] As used herein, the terms "dispersion," "emulsion," "dispersible," "dispersibility," "dispersed," "emulsified," and like terms refer to a material that is insoluble in a liquid medium but does not undergo gross phase separation therefrom. These terms may be used relatively, i.e., the dispersibility of a material increases or decreases, as determined by the context, meaning that more or less of the material is present in dispersed and separate form; or wherein the dispersion stability increases or decreases, as determined by the context. In various embodiments, the dispersion or emulsion is unstable or stable, as determined by the context, further wherein "stable" and similar terms mean kinetically stable, thermodynamically stable, hydrolytically stable, shear stable, thermally stable, or a combination of two or more thereof, and "unstable" means that one or more of phase separation and viscosity increase is observed.

[0061] As used herein, the term "thermally stable" or similar terms as applied to the antifouling polymers means that the polymer does not undergo substantial thermal degradation reactions when present in a petroleum process stream subjected to temperatures of about 20°C to 400°C.

[0062] Unless expressly stated otherwise, any carboxylate group present in any polymer described herein is recited with reference to the free carboxylic acid (i.e., "acidic group" or the like), wherein the reference is also intended to encompass any conjugate base (carboxylate) thereof, or a combination of the two, for example, as a single compound or residue in a single polymer chain.

[0063] As used herein, the terms "optional" or "optionally" mean that the subsequently described event or circumstance can but need not occur, and that the description includes instances where the event or circumstance occurs and instances where it does not.

[0064] As used herein, the term "about" used in describing the embodiments of the present disclosure to modify, for example, the amount of ingredients in the composition, concentration, volume, process temperature, process time, yield, flow rate, pressure and similar values, as well as the range thereof, refers to changes in the numerical amount that may occur, for example, by typical measurement and processing procedures for preparing compounds, compositions, concentrates or using formulations; by inadvertent errors in these procedures; by differences in the manufacture, source or purity of the starting materials or ingredients used to carry out the method, and similar close considerations. The term "about" also encompasses amounts that differ due to aging of a preparation with a specific initial concentration or mixture, and amounts that differ due to mixing or processing a preparation with a specific initial concentration or mixture. In the case of being modified by the term "about", the attached claims include equivalents of these amounts. Further, when "about" is used to describe any range of values, such as "about 1 to 5", the description refers to "1 to 5" and "about 1 to about 5" and "1 to about 5" and "about 1 to 5", unless specifically limited by the context.

[0065] As used herein, the terms "substantially" and "consisting essentially of" used in describing embodiments of the present disclosure to modify, for example, the type or amount of an ingredient in a composition, a property, a measurable amount, a method, a position, a value, or a range, refer to changes that do not affect the entire composition, property, amount, method, position, value, or range in a manner that invalidates the intended composition, property, amount, method, position, value, or range. Examples of intended properties include, by way of non-limiting example only, dispersibility, stability, rate, solubility, etc.; intended values ​​include weight of added components, concentration of added components, etc. Effects on the modified process include effects caused by changes in the type or amount of materials used in the process, changes in machine settings, effects of environmental conditions on the process, etc. (where the manner or degree of the effect does not negate one or more of the intended properties or results) and similar approximate considerations. Where modified by the terms "substantially" or "consisting essentially of", the appended claims include equivalents to these types and amounts of materials.

[0066] As used herein, any recited range of values ​​contemplates all values ​​within the range and should be interpreted as supporting a claim reciting any sub-range having endpoints with real values ​​within the range. By way of hypothetical illustrative example, the disclosed 1 to 5 range in this specification should be considered supporting claiming any of the following ranges: 1-5; 1-4; 1-3; 1-2; 2-5; 2-4; 2-3; 3-5; 3-4; and 4-5.

[0067] discuss

[0068] It has been discovered that fouling due to foulants in petroleum process streams can be reduced or eliminated using a combination of a dispersant polymer that is the reaction product of a maleic anhydride functional precursor polymer and a primary amine and an inhibitor that is a functionalized p-phenylenediamine substantially free of primary amino functionality.

[0069] The precursor polymer is a copolymer of C10-C36 alpha-olefin and maleic anhydride. In an embodiment, the alpha-olefin has 10 to 36 carbons, or 14 to 32 carbons, or 18 to 30 carbons, or 24 to 28 carbons, wherein the carbon number is an average number reflecting a blend of compounds, or a substantially single value determined by a user. The precursor polymer comprises alpha-olefin residues and maleic anhydride residues in a weight ratio of about 1:1 to about 1:5. When analyzed by gel permeation chromatography, the weight average molecular weight (M) of the precursor polymer is w ) is from about 5000 g / mol to about 100,000 g / mol. The precursor polymer is synthesized using conventional techniques, such as free radical addition polymerization principles and techniques familiar to those skilled in the art of polymer synthesis. The polymer is further analyzed using conventional methods familiar to polymer chemists, including gel permeation chromatography and infrared analysis to ensure that the target structure and molecular weight are achieved in the precursor polymer. The precursor polymer is further described in Comer et al., U.S. Patent No. 5,214,224, the contents of which are hereby incorporated herein in their entirety and for all purposes.

[0070] The precursor polymer is then reacted with a linear or branched C6-C30 primary amine or a mixture of such primary amines to form the corresponding dispersant polymer (or in embodiments where a mixture of amines is used, a dispersant polymer mixture). The linear or branched primary amine has 6 to 30, or 14 to 28, or 16 to 24, or 16 to 20 carbons, where the carbon number is an average reflecting a blend of compounds or a substantially single value determined by the user. The reaction is accomplished by contacting the precursor polymer with one or more primary amines at a temperature between about 20°C and 100°C. In embodiments, the contacting is performed using a molar ratio of amine moiety to anhydride moiety of about 1:2 to 2:1, or about 1:1 to 1:2, or about 2:3 to 3:2, or about 1:1 to 2:3, or about 1:1. In embodiments, the contacting is performed in a solvent; in some such embodiments, the solvent is a white spirit, i.e., a liquid petroleum product or a liquid mixture thereof intended for use as a solvent. Such white spirits include, for example, paraffinic solvents, mineral oil, "HAN" or heavy aromatic naphtha, mixtures thereof, and the like.

[0071] The dispersant polymer is soluble in non-polar solvents, ie, solvents having a dielectric constant of about 15 or less.

[0072] In an embodiment, the contact does not result in the formation of an imide moiety, and thus in some embodiments, the dispersant polymer is characterized by the substantial absence of an imide moiety. Such contact includes contact at a temperature between about 20°C and 100°C, such as about 30°C to 90°C, or about 40°C to 80°C, or about 50°C to 70°C. It can be appropriate, for example, to determine that the imide moiety is substantially absent by infrared analysis. In an embodiment, for example, when compared to a precursor polymer by infrared analysis, the dispersant polymer includes 0 mol% to about 20 mol% unreacted anhydride moieties, or 0 mol% to about 18 mol%, or 0 mol% to about 16 mol%, or 0 mol% to about 14 mol%, or 0 mol% to about 12 mol%, or 0 mol% to about 10 mol%, or 0 mol% to about 8 mol%, or 0 mol% to about 6 mol%, or 0 mol% to about 4 mol%, or 0 mol% to about 2 mol%, or 0 mol% to about 1 mol%, or 0 mol% to about 0.5 mol%, or 0 mol% to about 0.1 mol% unreacted anhydride moiety precursor polymer.

[0073] The composition including the dispersant polymer also includes an inhibitor, which is fPDA (functionalized p-phenylenediamine). fPDA is characterized by being substantially free of primary amino functional groups. fPDA comprises, consists essentially of, or consists of a compound having the formula

[0074]

[0075] Wherein R' is independently selected as a linear, branched, aromatic or alicyclic moiety containing 1 to 12 carbon atoms, optionally including one or more O, S, N or halogen atoms, provided that the fPDA does not include a primary amine moiety. In some embodiments, two R's are selected to be the same or substantially the same, wherein in other embodiments, R' is selected to be chemically different. In embodiments, the R' groups are independently phenyl, substituted phenyl or branched alkyl. A representative and non-limiting inhibitor structure is, for example,

[0076]

[0077] Wherein n is an integer from 1 to 8. In an embodiment, the inhibitor is N-(1,3-dimethylalkyl)-N'-phenyl-1,4-phenylenediamine or N-(1,4-dimethylalkyl)-N'-phenyl-1,4-phenylenediamine, such as N-(1,4-dimethylpentyl)-N'-phenyl-1,4-phenylenediamine, or N-(1,3-dimethylbutyl)-N'-phenyl-1,4-phenylenediamine, or a mixture of two or more thereof. fPDA is characterized by being soluble in non-polar solvents, i.e., solvents having a dielectric constant of about 15 or less.

[0078] The antifouling composition is soluble in liquid petroleum products or liquid petroleum process streams and non-polar solvents conventionally used to introduce compounds into petroleum process streams. Non-polar solvents are compounds that are liquid at 20°C and have a dielectric constant of less than 15. "Non-polar solvent" means a single non-polar solvent compound or a blend of two or more such compounds. The dispersant polymer and inhibitor are soluble in non-polar solvents, i.e., solvents having a dielectric constant of about 15 or less.

[0079] The ratio of the one or more dispersant polymers to the one or more inhibitors in the antifouling composition is from about 10: 1 to 1: 10 by weight, in some embodiments from about 1:5 to 5: 1, or about 2:5 to 5:2, or about 2:3 to 3:2, or about 1:3 to 3:1, or about 10:1 to 1:1, or about 5:1 to 1:1, or about 4:1 to 1:1, or about 3:1 to 1:1, or about 2:1 to 1: 1. Although the dispersant polymers and inhibitors are mutually soluble over a wider range than described herein, we have found that the stated ratios are more effective than other ratios for reducing scale in one or more petroleum process streams in the presence of synthetic foulants during selected processes and / or in selected petroleum processing equipment.

[0080] We have found that these antifouling polymers are thermally stable under conditions commonly employed or encountered in petroleum process streams and thus can be suitably added to one or more petroleum process streams prior to subjecting the process streams to one or more pyrolytic challenge processes, such as hydroprocessing. We have found that these antifouling polymers as a class are pyrolytically stable within petroleum process streams subjected to conventional conditions in petroleum processing equipment. That is, the antifouling polymers maintain their antifouling properties in one or more petroleum process streams while the treated petroleum process streams are subjected to temperatures of about 20°C to 400°C, or, for example, maintain their antifouling properties in a petroleum process stream such as a hydroprocessing unit, where temperatures of 400°C can be reached.

[0081] In an embodiment, the anti-fouling composition is a concentrate comprising a dispersant polymer, an inhibitor and a solvent having a dielectric constant of less than 15 or a mixture of two or more thereof. Such concentrates are not possible using the precursor polymer due to the inherently low solubility of the precursor polymer in solvents having a dielectric constant of less than 15. Similarly, suitable concentrates (at least 15% by weight solids) of, for example, a precursor polymer and an inhibitor cannot be prepared in a solvent having a dielectric constant of less than 15 due to the incompatibility of the components. However, the anti-fouling composition of the present invention is readily blended in a solvent having a dielectric constant of less than 15 to form a stable dispersion of at least 15% solids and up to 90% solids. In an embodiment, the anti-fouling composition is added to a solvent to form an anti-fouling concentrate, and the anti-fouling concentrate is then added to one or more petroleum process streams to form one or more treated petroleum process streams.

[0082] Thus, an antifouling concentrate is provided herein, comprising, consisting essentially of, or consisting of one or more dispersant polymers, one or more inhibitors, and one or more solvents. In an embodiment, the dielectric constant of the one or more solvents is about 15 or less. The solvent used to form the concentrate may be a petroleum solvent, i.e., a liquid petroleum product or a liquid mixture thereof intended for use as a solvent. Such petroleum solvents include, for example, paraffinic solvents, mineral oil, "HAN" or heavy aromatic naphtha, mixtures thereof, and the like. Such solvents include solvents having a dielectric constant of about 15 or less.

[0083] In an embodiment, the antifouling concentrate includes about 15 wt % to about 90 wt % of one or more dispersant polymers and one or more inhibitors as described above, or about 15 wt % to 85 wt %, or about 15 wt % to 80 wt %, or about 15 wt % to 75 wt %, or about 15 wt % to 70 wt %, or about 15 wt % to 65 wt %, or about 15 wt % to 60 wt %, or about 15 wt % to 55 wt %, or about 15 wt % to 50 wt %, or about 15 wt % to 45 wt %, or about 15 wt % to 40 wt %, or about 15 wt % to 35 wt %, or about 15 wt % to 30 wt %, or about 15 wt % to 25 wt %, or about 20 wt % to 80 wt %, or about 30 wt % to 50 wt %, or about 50 wt % to 90 wt %, or about 50 wt % to 80 wt %, or about 30 wt % to 70 wt %, or about 40 wt % to 70 wt % of an antifouling composition which is a combination of one or more dispersant polymers and one or more inhibitors as described above.

[0084] The anti-scaling concentrate is stable at a temperature of about 60°C to -40°C, wherein the concentrate is pumpable or pourable within this range and no further observable precipitate is formed. The lower end of the range reflects the favorable and stable nature of the anti-scaling concentrate. Thus, the anti-scaling concentrate is characterized as being pumpable or pourable at a temperature of about 0°C to as low as -40°C as measured according to ASTM D-97, or being pumpable or pourable at about 0°C to -40°C, or about -10°C to -40°C, or about -15°C to -40°C, or about -20°C to -40°C, or about -20°C to -30°C as measured according to ASTM D-97, which includes a procedure of reducing the temperature of the composition by 3°C / minute, and recording the temperature at which no movement of the concentrate is observed as the pour point of the composition.

[0085] In an embodiment, the antifouling composition is pyrolytically stable and has antifouling properties in petroleum process streams when subjected to a temperature of about 20°C to 400°C, such as about 100°C to 400°C, or about 100°C to 350°C, or about 100°C to 300°C, or about 100°C to 250°C, or about 100°C to 200°C, or about 100°C to 150°C. In an embodiment, the antifouling composition forms a stable dispersion with scale present in a petroleum process stream during petroleum processing operations, wherein the treated petroleum process stream is subjected to a temperature of about 20°C to 400°C, such as about 100°C to 400°C, or about 100°C to 350°C, or about 100°C to 300°C, or about 100°C to 250°C, or about 100°C to 200°C, or about 100°C to 150°C. In an embodiment, the antifouling composition reduces or prevents fouling in a petroleum processing stream during a petroleum processing operation, wherein the treated petroleum process stream is subjected to a temperature of about 20°C to 400°C, e.g., about 100°C to 400°C, or about 100°C to 350°C, or about 100°C to 300°C, or about 100°C to 250°C, or about 100°C to 200°C, or about 100°C to 150°C.

[0086] We have further discovered that the antifouling composition is effective in reducing or preventing fouling due to natural and synthetic foulants when the composition is added to a petroleum process stream in an amount corresponding to about 1 ppm to 1000 ppm, based on the total weight of the combination of the dispersant polymer and the inhibitor, or about 5 ppm to 900 ppm, or about 10 ppm to 900 ppm, or about 100 ppm to 900 ppm, or about 100 ppm to 800 ppm, or about 100 ppm to 700 ppm, or about 100 ppm to 600 ppm, or about 100 ppm to 500 ppm, or about 100 ppm to 400 ppm, or about 100 ppm to 300 ppm, or about 100 ppm to 200 ppm, or about 1 ppm to 500 ppm, or about 10 ppm to 500 ppm, or about 10 ppm to 400 ppm, or about 10 ppm to 300 ppm, based on the total weight of the antifouling composition added to the liquid petroleum process stream to form the treated liquid petroleum process stream.

[0087] Treated petroleum products are petroleum products comprising a total of about 1ppm to 1000ppm by weight of the anti-fouling composition. Treated liquid petroleum products are liquid petroleum products comprising a total of about 1ppm to 1000ppm by weight of the anti-fouling composition. Treated oil process streams are petroleum products placed in oil processing equipment and comprising a total of about 1ppm to 1000ppm by weight of the anti-fouling composition. Treated liquid oil process streams are placed in oil processing equipment and comprising a liquid petroleum product comprising a total of about 1ppm to 1000ppm by weight of the anti-fouling composition. The anti-fouling composition comprises, is essentially composed of or is composed of a dispersant polymer and an inhibitor, wherein the ratio of the dispersant polymer to the inhibitor is about 1:10 to 10:1.

[0088] The treated petroleum product has at least one of the following properties during and after its acquisition, transportation, storage or cooling: kinetic stability, thermodynamic stability, hydrolysis stability, shear stability, heat stability, or a combination of two or more thereof. The treated petroleum product has at least one of the following properties during and after one or more manual operations that will cause synthetic dirt to form: kinetic stability, thermodynamic stability, hydrolysis stability, shear stability, heat stability, or a combination of two or more thereof. Such manual operations include, but are not limited to, refining, processing, distillation, reaction or heating one or more petroleum products. In an embodiment, the manual operation is hydrotreating. In order to prevent synthetic dirt from forming, the anti-fouling composition must be applied to the liquid petroleum process stream before the process stream is subjected to a process that will cause dirt to be generated. Therefore, for example, if the process to be adopted is hydrotreating, the anti-fouling composition must be applied to the liquid petroleum process stream before the process stream carrying out the hydrotreating process.

[0089] The inhibitor is used in antifouling compositions (as well as the treated petroleum products and treated petroleum process streams referred to herein) to reduce the formation of synthetic foulants in petroleum process streams. Paraphenylenediamine and related compounds are known to have free radical inhibition activity and antioxidant activity in some chemical systems. Such inhibitors are known to be added to one or more liquid petroleum process streams to inhibit the formation of free radicals that lead to oxidation and polymerization and the resulting byproducts - which are synthetic foulants in liquid petroleum process streams. When used alone, the inhibitor does not act as a dispersant; that is, the inhibitor does not appear to have comparable properties for dispersing foulants in any petroleum product.

[0090] In sharp contrast, dispersant polymers are not inhibitors and are not expected to have inhibitory properties. That is, dispersant polymers are not expected to reduce or prevent the formation of synthetic foulants in petroleum process streams. Rather, the role of dispersant polymers is assumed to be merely that of a dispersant of any natural or synthetic foulants present in the petroleum process stream.

[0091] Thus, inhibitors and dispersants each have mutually exclusive intended effects in a petroleum process stream: inhibitors prevent the formation of certain synthetic foulants in a petroleum process stream but do not disperse the foulants; dispersant polymers disperse foulants in a petroleum process stream but do not prevent the formation of synthetic foulants. Inhibitors and dispersants are expected to behave in an additive manner when combined, i.e., properties individually attributable to inhibitors and dispersant polymers are expected to translate into substantially the same properties when combined as an antifoulant composition and applied to a liquid petroleum product or liquid petroleum process stream.

[0092] However, we have observed that the antifouling composition has a stronger inhibitory effect in a liquid petroleum product or liquid petroleum process stream than an equivalent amount of the inhibitor alone. This effect is completely unexpected to the skilled person: there is nothing in any of the previously observed properties of the inhibitor or the dispersant polymer, nor in the chemical structures of the two different components to suggest that the addition of a dispersant to the inhibitor increases the inhibitory properties of the mixture compared to an equivalent amount of the inhibitor alone. Furthermore, while the antifouling composition has stronger inhibitory properties than expected, the dispersing properties of the antifouling composition are about the same as the expected dispersing properties of the dispersant polymer alone. Thus, the increase in the inhibitory properties of the antifouling composition is not commensurate with any loss in the properties of the dispersant.

[0093] The improved inhibitory properties of the antifouling composition compared to the inhibitor alone are determined by measuring the inflection point of the composition according to ASTM-D525. According to the test, a liquid petroleum sample is oxidized at 690 kPa to 705 kPa and 15°C to 25°C in a pressure vessel filled with oxygen, and then heated to a temperature of 98°C to 102°C. The pressure in the container is monitored over time. The inflection point is defined as the point in the pressure-time curve where the pressure drop is exactly 14 kPa in the 15 minutes before it and does not drop less than 14 kPa in the 15 minutes after it. The induction period is defined as the time elapsed between placing the pressure vessel in a temperature bath and the inflection point. Using this test, the induction period and the inflection point represent the tendency of a liquid petroleum product to form synthetic fouling during storage.

[0094] In embodiments, the antifouling composition provides an induction period that is about 2X to 10X longer (where "2X" = 100% increase) than the liquid petroleum product alone, e.g., about 3X to 10X longer, or about 4X to 10X longer, or about 5X to 10X longer than the liquid petroleum product alone, when measured according to ASTM-D525. In addition, the antifouling composition provides an induction period that is about 1.5X to 5.0X longer than the induction period due to the addition of the inhibitor alone, for example, about 1.5X to 4.5X, or about 1.5X to 4.0X, or about 1.5X to 3.5X, or about 1.5X to 3.0X, or about 1.5X to 2.5X, or about 1.5X to 2.0X, or about 2.0X to 5.0X, or about 2.0X to 4.5X, or about 2.0X to 4.0X, or about 2.0X to 3.5X, or about 2.0X to 3.0X, or about 2.0X to 2.5X longer than the induction period due to the addition of the inhibitor alone to the liquid petroleum product or liquid petroleum process stream.

[0095] In some embodiments, the treated petroleum process streams experience significantly less fouling of petroleum processing equipment that is contacted during one or more petroleum processing operations than the corresponding untreated petroleum process streams. Reduction or prevention of fouling is observed in one or more petroleum process streams during placement of the treated petroleum process streams within one or more petroleum processing units, or during storage of petroleum products within storage vessels.

[0096] Thus, also disclosed herein is a method of reducing scale in one or more petroleum process streams, the method comprising, consisting essentially of, or consisting of the following steps: applying from about 1 ppm to 1000 ppm by weight or by volume of an anti-scaling composition to a liquid petroleum process stream to form a treated petroleum process stream. The anti-scaling agent composition comprises, consists essentially of, or consists of a combination of one or more dispersant polymers and one or more inhibitors, wherein the dispersant polymer is an amide reaction product of a maleic anhydride functional precursor polymer and a primary amine, and the inhibitor is a functionalized p-phenylenediamine substantially free of primary amino functional groups. Any of the above compositions may be used in conjunction with a method of reducing scale, wherein the method comprises applying from about 1 ppm to 1000 ppm by weight or by volume of an anti-scaling composition to a liquid petroleum process stream to form a treated liquid petroleum process stream.

[0097] The antifouling composition is advantageously added to a petroleum product or petroleum process stream to achieve about 1 ppm to 1000 ppm by weight of the combined dispersant polymer plus inhibitor, or to achieve about 5 ppm to 500 ppm, based on the weight of the petroleum product or petroleum process stream selected by the user. In embodiments, or about 10 ppm to 1000 ppm, or about 10 ppm to 500 ppm, or about 20 ppm to 500 ppm, or about 30 ppm to 500 ppm, or about 40 ppm to 500 ppm, or about 50 ppm to 500 ppm, or about 60 ppm to 500 ppm, or about 70 ppm to 500 ppm, or about 80 ppm to 500 ppm, or about 90 ppm to 500 ppm, or about 100 ppm to 500 ppm, or about 5 ppm to 500 ppm is added to the petroleum product or petroleum process stream. ppm, or about 5 ppm to 400 ppm, or about 5 ppm to 350 ppm, or about 5 ppm to 300 ppm, or about 5 ppm to 250 ppm, or about 5 ppm to 200 ppm, or about 5 ppm to 150 ppm, or about 5 ppm to 100 ppm, or about 10 ppm to 300 ppm, or about 10 ppm to 250 ppm, or about 50 ppm to 250 ppm, or about 50 ppm to 200 ppm, or about 100 ppm to 200 ppm of a combination of dispersant polymer plus inhibitor.

[0098] We found that the antifouling composition is thermally stable and further observed to maintain antifouling properties during one or more petroleum processing operations. That is, the antifouling composition maintains the antifouling properties as described herein while the treated petroleum process stream is subjected to temperatures of about 20°C to 400°C during one or more petroleum processing operations. Such petroleum processing includes hydroprocessing. Therefore, the method, in some embodiments, also includes subjecting the treated petroleum process stream to a temperature of about 20°C to 400°C; such subjection does not result in the observation of fouling of the surfaces of the petroleum processing equipment contacted by the treated petroleum process stream.

[0099] The anti-fouling composition is applied to the liquid petroleum process stream in batches, continuously, or semi-continuously. In some embodiments, the application is manual; in other embodiments, the application is automated. In embodiments, the amount of the anti-fouling composition applied in a selected unit of time varies with the variable composition of the relevant petroleum process stream. Such dosage variability can be performed manually: by periodic testing of the internal surfaces of the liquid petroleum processing equipment, and then adjusting the amount of the anti-fouling composition up or down in response to the observation of more or less fouling, respectively; or by automatically monitoring one or more conditions inside the petroleum processing equipment and issuing a signal that more anti-fouling composition needs to be applied to the liquid petroleum process stream.

[0100] In embodiments, the petroleum product present in the one or more petroleum process streams is crude oil, crude oil after distillation, heavy oil, asphalt, coker charge, hydrotreater influent, flashed crude oil, light cycle oil, or diesel or naphtha refinery stream. In embodiments, petroleum processing equipment is any equipment generally associated with the collection, processing, transportation or storage of one or more of crude oil, crude oil after distillation, crude oil fractions, heavy oil, asphalt, coker charge, flashed crude oil, light cycle oil, or diesel or naphtha refinery streams, including pipelines and related infrastructure for connecting process equipment items together for processing process streams disposed therein.

[0101] In an embodiment, the anti-fouling composition is applied to a petroleum process stream by dissolving or dispersing the dispersant polymer and the inhibitor in a solvent to form the anti-fouling composition, and then adding the anti-fouling composition to the petroleum process stream to form a treated petroleum process stream. The solvent may be a petroleum solvent, i.e., a liquid petroleum product or liquid mixture thereof intended for use as a solvent. Such petroleum solvents include, for example, paraffinic solvents, mineral oil, "HAN" or heavy aromatic naphtha, mixtures thereof, and the like.

[0102] A treated petroleum process stream, which in embodiments is a treated liquid petroleum product placed in fluid contact with the interior surfaces of petroleum processing equipment, results in a reduction or elimination of fouling of the contacted interior surfaces. In embodiments, fouling is measured as a relative increase in solids retention in the treated petroleum product compared to solids retention in an untreated petroleum product over the same time period. In embodiments, fouling is measured as a relative decrease in the weight or volume of precipitate resulting from the same contact time of the treated petroleum process stream in the relevant petroleum processing equipment item relative to a selected contact time of the petroleum processing equipment with the corresponding untreated petroleum process stream. In other words, the reduction in fouling is a relative reduction in the measured weight or volume of solids deposited or precipitated from the petroleum processing equipment in contact with the treated petroleum process stream over a selected time period compared to the weight or volume of solids deposited or precipitated from the untreated petroleum process stream over the same time period.

[0103] The treated process stream results in reduced or eliminated fouling of the contacted internal surfaces compared to the corresponding (untreated) process stream. In an embodiment, the treated process stream experiences a 50% to 100% reduction in fouling compared to the corresponding process stream (i.e., the untreated process stream), or a measurable reduction in fouling of the internal surfaces of the petroleum processing equipment compared to the corresponding process stream is about 60% to 100%, or about 70% to 100%, or about 80% to 100%, or about 90% to 100%, or about 95% to 100%, or about 97% to 100%, or about 98% to 100%. In an embodiment, the percentage reduction in fouling is determined as defined in ASTM-D525. The test is understood by those skilled in the art to be a prediction of the relative degree of expected fouling in one or more petroleum process streams.

[0104] experiment

[0105] The following examples are intended to illustrate experimental examples of the present invention. These examples are not limited to the scope of the appended claims. It should be appreciated that various modifications and changes may be made without following the experimental examples described herein without departing from the scope of the claims.

[0106] Example 1

[0107] According to the procedure outlined in Comer et al., U.S. Pat. No. 5,214,224, polyalkenyl succinic acid, which is a copolymer of C24-C28 alpha-olefins and maleic anhydride (CAS No. 68459-79-0), was obtained. 50 g of the polymer (obtained as a solid, with a content of 100% active polymer) was then dispersed in 100 g of HAN (heavy aromatic naphtha), and the dispersion was heated to 60-65° C. with constant stirring. 20 g of oleylamine (20 g) was then slowly added to the mixture over 30 minutes. The temperature of the reaction mixture was observed to rise to about 80° C. The mixture was stirred for an additional 2 hours while maintaining the temperature at 60-65° C. The anhydride peaks (1780 and 1711 cm -1 ) disappearance and the amide peak (1679cm -1 )’s appearance.

[0108] When the reaction was determined to be complete, an additional 100 g of HAN was added to the mixture and the mixture was stirred for an additional 30 minutes. The mixture was then allowed to cool to ambient temperature and filtered to remove trace amounts of insoluble material in the reaction vessel. The product was observed to be 26 wt% solids in HAN and is hereinafter referred to as the "dispersant polymer product" or the product of Example 1.

[0109] Example 2-7

[0110] The inflection point and induction period of the liquid petroleum product in the presence of the polymer of Example 1 are determined using ASTM-D525. The treated or untreated liquid petroleum sample is oxidized at 690kPa to 705kPa, at 15°C to 25°C in a pressure vessel filled with oxygen, and then heated to a temperature of 98°C to 102°C. The pressure in the container is monitored over time. In ASTM-D525, the inflection point is defined as the point in the pressure-time curve where the pressure drop is just 14kPa in the 15 minutes before it, and the drop is not less than 14kPa in the 15 minutes after it. The induction period in ASTM-D525 is defined as the time passed between placing the pressure vessel in a temperature bath and the inflection point. Using this test, the induction period and inflection point results are measured to provide an indication of the tendency of the liquid petroleum product to form synthetic dirt during storage. A shorter induction period indicates that the dispersion is less stable.

[0111] Using ASTM-D525, the induction period of a heavy coker naphtha stream was determined to be 1.3 hours in the absence of additives (as a control). The test was then repeated using materials added to a heavy coker naphtha stream, as shown in Table 1. The corresponding induction periods for the control and various petroleum products with added compounds are also listed in Table 1 as Examples C and 2-4 and 6. Referring to Table 1, Dispersant A is a polyalkenyl succinate, 20-25% in HAN; Dispersant B is a copolymer of C24-C28 alpha-olefins and maleic anhydride (CAS No. 68459-79-0), 15-20% in HAN; and Inhibitor C is a blend of N-(1,3-dimethylbutyl)-N'-phenyl-1,4-phenylenediamine and N-(1,4-dimethylpentyl)-N'-phenyl-1,4-phenylenediamine.

[0112] A blend of N-(1,3-dimethylbutyl)-N'-phenyl-1,4-phenylenediamine and N-(1,4-dimethylpentyl)-N'-phenyl-1,4-phenylenediamine was added to the dispersant polymer product of Example 1 (26 wt% solids in HAN) in an amount corresponding to a weight ratio of 70:30 dispersant polymer:inhibitor blend in HAN to form an anti-fouling composition. The anti-fouling composition was added to a heavy coker naphtha stream in varying amounts corresponding to the desired inhibitor ppm equivalents. Thus, Example 5 of Table 1 shows the induction period of a heavy coker naphtha stream in combination with 250 ppm of the anti-fouling composition (which corresponds to 75 ppm of inhibitor added by adding the anti-fouling composition). Thus, Example 7 of Table 1 shows the induction period of a heavy coker naphtha stream in combination with 833 ppm of the anti-fouling composition (which corresponds to 250 ppm of inhibitor). Property comparisons were made by comparing Examples 4 and 5 in Table 1. Similarly, a property comparison is also made by comparing Examples 6 and 7 in Table 1.

[0113] Table 1.Induction Period measured according to ASTM-D525 on a heavy coker naphtha stream with and without the specified additives.

[0114] Examples Additives, by weight Induction period, hours C none 1.3 2 Dispersant A, 250ppm 1.2 3 Dispersant B, 250ppm 1.2 4 Inhibitor C, 75 ppm 1.6 5 Antifouling composition, 250 ppm (75 ppm equivalent of inhibitor) 1.9 6 Inhibitor C, 250ppm 3.0 7 Antifouling composition, 833 ppm (250 ppm equivalent of inhibitor) 4.3

[0115] The induction period of the heavy coker naphtha stream including the anti-fouling composition is longer than the corresponding induction period observed for an equivalent amount of the inhibitor alone. In other words, the functionalized p-phenylenediamine inhibitors provide stronger inhibitory properties in the presence of the anti-fouling polymer than when they are used alone - even though the anti-fouling polymers themselves do not exhibit inhibitory properties. This result is completely unexpected by the skilled person, because the effect of the dispersant is different from that of the inhibitor, and the two effects are expected to be complementary or additive at best. Dispersants are not expected to affect inhibition and inhibitors are not expected to affect dispersion. However, this example shows that the presence of a dispersant improves inhibition of petroleum products as measured by the induction period according to ASTM-D525.

[0116] Example 8

[0117] Using the procedure and additive compositions of Examples 2-7, the induction period of the coker naphtha feed was tested according to ASTM-D525. No additive resulted in an induction period of 1.96 hours; 500 ppm of Inhibitor C provided an induction period of 6.35 hours; and 1666 ppm of the antifoulant composition (corresponding to 500 ppm of Inhibitor C) provided an induction period of greater than 8.0 hours: that is, the test was stopped at 8.0 hours without reaching the end of the induction period.

[0118] Example 9

[0119] Using the procedures and additive compositions of Examples 2-7, the induction period of a naphtha feed pretreated to remove sulfur compounds was tested according to ASTM-D525. No additive resulted in an induction period of 1 hour; 250 ppm of Inhibitor C provided an induction period of 2.5 hours; and 833 ppm of the antifoulant composition (corresponding to 250 ppm of Inhibitor C) provided an induction period of 3.1 hours.

[0120] Examples 8 and 9 demonstrate that the technology described herein is applicable to a range of petroleum process streams and feeds having different process histories and different compositional contents.

[0121] Example 10

[0122] The pour point of the dispersant polymer in the concentrate was determined using ASTM D-97 with HAN as the solvent. The pour point of a 15 wt % dispersion of the polyalkenyl succinamide having CAS No. 68459-79-0 in HAN was found to be -12°C. The pour point of a 15 wt % dispersion of the polymer synthesized in Example 1 in HAN was found to be -26°C. At -26°C, it was further observed that the dispersion of the polymer of Example 1 had no precipitation.

[0123] As can be appreciated from the foregoing, the polymer of Example 1 provides a concentrate having a pour point low enough to provide product pumpability and pourability in the field, even under commonly encountered winter conditions. In addition, the pumpable / pourable product including the polymer of Example 1 remains essentially single-phase when subjected to temperatures as low as -26°C; that is, the dispersion is stable at this temperature. These stabilities of the concentrate are not altered when an inhibitor is added to the concentrate.

[0124] The present invention disclosed illustratively herein may be suitably practiced in the absence of any elements not specifically disclosed herein. In addition, as described herein, the various embodiments of the present invention and each embodiment are intended to be used alone or in combination with any other embodiment described herein and modifications, equivalents, and alternatives thereof. In various embodiments, the present invention suitably includes, consists essentially of, or consists of the elements described herein and claimed for protection according to the claims. It should be appreciated that various modifications and changes may be made without following the example embodiments and applications shown and described herein and without departing from the scope of the claims.

Claims

1. A method for reducing fouling in one or more petroleum process streams, the method comprising: reacting a precursor polymer with a primary amine to form a dispersant polymer, wherein the primary amine is defined by the formula R-NH2, wherein R is a straight or branched hydrocarbon moiety containing from 6 to 30 carbon atoms; wherein the reaction is accomplished by contacting the precursor polymer with one or more primary amines in a solvent at a temperature of about 40°C to 80°C; wherein the dispersant polymer is characterized by the substantial absence of anhydride moieties and imide moieties as determined by infrared analysis; and wherein the dispersant polymer comprises polymerized residues of one or more C10-C36 alpha-olefins and maleic anhydride, and wherein 80 mol% to 100 mol% of the maleic anhydride residues are reacted with the primary amine; One or more dispersant polymers are combined with one or more inhibitors to form an antifouling composition, wherein the one or more inhibitors comprise a functionalized p-phenylenediamine defined by the formula wherein R' is independently selected to be a linear, branched, aromatic or alicyclic moiety comprising from 1 to 12 carbon atoms, optionally including one or more O, S, N or halogen atoms, provided that the functionalized p-phenylenediamine does not include a primary amine moiety; combining the anti-fouling composition with a petroleum product to form a treated petroleum product comprising from about 1 ppm to 1000 ppm by weight of the anti-fouling composition; as well as The treated petroleum product is applied to a petroleum processing facility to form a treated petroleum process stream.

2. The method of claim 1, wherein the solvent is white spirit.

3. The process of claim 1, wherein the solvent is heavy aromatic naphtha. The method of claim 1 , wherein the contacting comprises contacting at a temperature of 50° C. to 70° C.

5. The method of claim 1, wherein the precursor polymer is a copolymer of a C24-C28 alpha-olefin and maleic anhydride, the primary amine is oleylamine, and the solvent is heavy aromatic naphtha; wherein the method comprises dispersing the precursor polymer in the solvent to form a dispersion, and heating the dispersion to a temperature of 60-65° C. and then mixing with the primary amine.

6. The method of claim 5, further comprising monitoring the dispersant polymer by infrared.

7. The method of claim 1, wherein the molar ratio of the primary amine to the polymerized residues of maleic anhydride is about 1:2 to 2:

1.

8. The method of claim 1, wherein the molar ratio of the primary amine to the polymerized residues of maleic anhydride is about 1:

1.

9. The method according to claim 1, wherein the C10-C36 α-olefin is a C24-C28 α-olefin.

10. The method according to claim 1, wherein the C10-C36 α-olefin is a C18-C30 α-olefin.

11. The method of claim 1, wherein the weight ratio of polymerized residues of C10-C36 alpha-olefins to polymerized residues of maleic anhydride in the precursor polymer is about 1:1 to 1:

5.

12. The method of claim 1, wherein the precursor polymer has a weight average molecular weight of about 5,000 g / mol to about 100,000 g / mol as analyzed by gel permeation chromatography.

13. The method of claim 1, wherein the primary amine is oleylamine.

14. The method of claim 1, wherein the antifouling composition is a concentrate comprising 15 wt% to 90 wt% of a combination of a dispersant polymer and one or more inhibitors.

15. The method of claim 1, wherein one or more R' is phenyl, substituted phenyl, or branched alkyl.

16. The method of claim 1, wherein the one or more inhibitors comprise wherein n is an integer from 1 to 8.

17. The method of claim 1, wherein the ratio of the dispersant polymer to the one or more inhibitors in the antifouling composition is about 5:1 to 1:5 by weight.

18. The method of claim 1 further comprising subjecting the treated petroleum process stream to a temperature of about 100°C to 400°C.

19. Use of a dispersant polymer in a method of increasing the induction period of a functionalized p-phenylenediamine inhibitor in a petroleum process stream, the functionalized p-phenylenediamine inhibitor having the formula wherein R' is independently selected to be a linear, branched, aromatic or alicyclic moiety comprising from 1 to 12 carbon atoms, optionally including one or more O, S, N or halogen atoms, provided that the functionalized p-phenylenediamine does not include a primary amine moiety; wherein the method comprises mixing a functionalized p-phenylenediamine inhibitor with a dispersant polymer in a weight ratio of 5:1 to 1:5 to form an antifouling composition, and applying 1 ppm to 1000 ppm of the antifouling composition to a petroleum process stream, wherein the dispersant polymer comprises polymerized residues of one or more alpha-olefins and maleic anhydride, and wherein 80 mol % to 100 mol % of the maleic anhydride residues are reacted with a primary amine defined by the formula R-NH2, wherein R is a linear or branched hydrocarbon moiety containing 6 to 30 carbon atoms or a mixture of two or more such moieties; and wherein the dispersant polymer is characterized by the absence of anhydride moieties and imide moieties as determined by infrared analysis.

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