Water-based demulsifier formulations with enhanced corrosion inhibition properties

Abstract

The present invention discloses a water-based demulsifier comprising two or more demulsifying resins, a surfactant, a hydrophilic linker, and a base solvent, the base solvent being water. In various embodiments, the two or more demulsifying resins include an acid catalyzed alkoxylated alkylphenol resin, a base catalyzed alkoxylated alkylphenol resin, a polyol resin, and a diepoxide resin. In one aspect, a method of using a water-based demulsifier with a desalter includes the steps of providing and applying the water-based demulsifier at the desalter wherein the water-based demulsifier comprises an acid-catalyzed alkoxylated alkylphenol resin, a base-catalyzed alkoxylated alkylphenol resin, a surfactant, a hydrophilic linker, and a base solvent. In yet another aspect, the water-based demulsifier comprises two or more demulsifying resins, a surfactant, a hydrophilic linker, and water as a base solvent, where the hydrophilic linker comprises a C3-C18 branched chain linker, which may be a branched alkyl alcohol, a branched diol, or a branched alkyl glycerol.

Description

[0001] Related applications

[0002] This application claims the benefit of U.S. Provisional Patent Application Serial No. 18 / 373,206, filed on September 26, 2023, entitled “Water-Based Demulsifier Formulation with Enhanced Corrosion Inhibition Property,” the disclosure of which is incorporated herein by reference. Technical Field

[0003] This application generally relates to water-based demulsifiers and methods of using such water-based demulsifiers. Background Technology

[0004] Crude oil typically contains water, inorganic salts, suspended solids, and water-soluble trace metals. To reduce corrosion, clogging, and scaling in equipment, and to prevent catalyst poisoning in processing units, crude oil in refineries must be treated to remove these contaminants, namely water and associated salts. This process is known as "desalting."

[0005] Contaminants are removed from crude oil in the desalting vessel. Before entering the desalting unit, the crude oil is mixed with fresh water (or "wash water") to form an emulsion. This emulsion mixes the wash water with the contaminants in the oil, so that unwanted contaminants are distributed into the emulsion water.

[0006] Demulsifiers are injected to break down emulsions into oil and water phases. Demulsifiers promote the flocculation of oil droplets and the coalescence of water droplets, resulting in oil-water separation within the time frame required by refinery production limits. Current demulsifier formulations typically contain large amounts of carbon-rich aromatic solvents, which emit carbon dioxide and are expensive.

[0007] The growing emphasis on environmental solutions is driving the oil and gas industry to seek more environmentally friendly chemicals. To reduce carbon emissions and costs, the expectation is to replace aromatic solvents in current demulsifiers with water as the base solvent. Unfortunately, simply replacing aromatic solvents with water causes severe corrosion problems—both general corrosion and pitting—that are nearly impossible to treat with existing corrosion inhibitors. Pitting is particularly problematic because it is more difficult to detect, predict, and target than general corrosion. Even small pits that result in minimal total metal loss can lead to large-scale equipment failure. Replacing aromatic solvents with water alone also leads to instability and separation at elevated temperatures, such as those encountered in the field when demulsifiers are stored in sunlight.

[0008] Therefore, there is a need for cost-effective and environmentally friendly treatments for the oil and gas industry. This disclosure addresses these and other deficiencies in the prior art. Summary of the Invention

[0009] The disclosed inventive concept generally relates to a water-based demulsifier formulation. In one aspect, a water-based demulsifier is disclosed, comprising an acid-catalyzed alkoxylated alkylphenol resin, a base-catalyzed alkoxylated alkylphenol resin, a surfactant, a hydrophilic connector, and water as a base solvent. Optionally, the water-based demulsifier comprises a polyol resin or a diester resin.

[0010] On the other hand, a method for using a water-based demulsifier in a desalination process includes the steps of providing the water-based demulsifier and applying the water-based demulsifier at the desalination unit. The water-based demulsifier comprises an acid-catalyzed alkoxylated alkylphenol resin, an alkali-catalyzed alkoxylated alkylphenol resin, a surfactant, a hydrophilic connector, and water as a base solvent.

[0011] In another aspect, water-based demulsifiers comprise two or more demulsifying resins, a surfactant, a hydrophilic linker, and water as a base solvent. The two or more demulsifying resins may include acid-catalyzed alkoxylated alkylphenol resins, base-catalyzed alkoxylated resins, polyol resins, and diepoxide resins. The hydrophilic linker includes a C3-C18 branched linker, which may be a branched alkyl alcohol, a branched diol, or a branched alkyl glycerol. Detailed Implementation

[0012] It has been found that using hydrophilic connectors and surfactants can improve the homogeneity of demulsifiers in water. Water-based demulsifiers can be used to overcome severe corrosion, including pitting corrosion, on low-metallurgical carbon steels, which is often associated with the use of water instead of aromatic solvents in the demulsifier formulation. Compared to other demulsifier formulations containing water, water-based demulsifiers also exhibit improved stability and separation at elevated temperatures. In contrast to aromatic solvents, using water as the base solvent in water-based demulsifiers effectively reduces the carbon footprint of the demulsification process and lowers costs by almost half.

[0013] According to the various embodiments disclosed herein, the water-based demulsifier comprises two or more demulsifying resins, a surfactant, a hydrophilic connector, and water as a base solvent. In various embodiments, the two or more demulsifying resins include acid-catalyzed alkoxylated alkylphenol resins, base-catalyzed alkoxylated alkylphenol resins, polyol resins, and diepoxide resins.

[0014] Suitable surfactants include C8-C24 alcohol ethoxylates, alkyl diphenyl ether disulfonates, biosurfactants, and combinations thereof. Biosurfactants (if present) may include glucosides, rhamnolipids, alkyl polyglycosides (including but not limited to alkyl polyglucoside carboxylates), sophorolipids, lecithin, lipopeptides (such as surfactants), and betaine (C5H...). 11 NO2), emulsifiers (emulsan), and combinations thereof.

[0015] Hydrophilic connectors within water-based cleaners may include branched connectors and combinations of branched and straight connectors. In some embodiments, the hydrophilic connector may have one or more branched connectors, wherein suitable branched connectors include branched C3-C18 alkyl alcohols, branched C3-C18 glycols, and branched C3-C18 alkylglycerols. These branched connectors provide stability and improve the viscosity of the water-based cleaner due to a greater amount of interaction at the oil / water interface. Suitable straight connectors include straight-chain C1-C18 alkyl glycols; straight-chain C1-C18 alkyl alcohols; straight-chain C1-C18 alkylglycerols; polymers, including but not limited to polyethylene glycol (PEG), polypropylene glycol (PPG), block copolymers having PEG and / or PPG, and random copolymers having PEG and / or PPG; and combinations thereof.

[0016] In several embodiments, the water-based demulsifier comprises an acid-catalyzed alkoxylated alkylphenol resin, a base-catalyzed alkoxylated alkylphenol resin, or both. Both the acid-catalyzed and base-catalyzed alkoxylated alkylphenol resins can comprise mixtures of carbon chains having various chain lengths. In some embodiments, the chains in the acid-catalyzed alkoxylated alkylphenol resin may include C4-C12 alkyl chains. In some embodiments, the base-catalyzed alkoxylated alkylphenol resin may also include C4-C12 alkyl chains. Both the acid-catalyzed and base-catalyzed resins in their respective mixtures may primarily comprise C9-C12 chains.

[0017] In one embodiment, the water-based demulsifier comprises between about 5% by weight and about 40% by weight of an acid-catalyzed alkoxylated alkylphenol resin, between about 5% by weight and about 40% by weight of an alkali-catalyzed alkoxylated alkylphenol resin, between about 1% by weight and about 10% by weight of a surfactant, between about 1% by weight and about 20% by weight of a hydrophilic binder, and between about 20% by weight and about 60% by weight of a base solvent.

[0018] In another embodiment, the water-based demulsifier comprises between about 9% to about 15% by weight of an acid-catalyzed alkoxylated alkylphenol resin, between about 9% to about 20% by weight of an alkali-catalyzed alkoxylated alkylphenol resin, between about 2% to about 6% by weight of a surfactant, between about 5% to about 10% by weight of a branched connector, between about 5% to about 10% by weight of a straight connector, and between about 40% to about 60% by weight of a base solvent.

[0019] In yet another embodiment, the water-based demulsifier comprises about 12% by weight of an acid-catalyzed alkoxylated alkylphenol resin, about 15% by weight of an alkali-catalyzed alkoxylated alkylphenol resin, about 5% by weight of a surfactant, about 9% by weight of a branched connector, about 6% by weight of a straight connector, and about 53% by weight of a base solvent.

[0020] In several embodiments, the water-based demulsifier comprises a polyol resin. The inclusion of a polyol resin in a water-based demulsifier is useful for heavier crude oils that may contain more solids. As a non-limiting example, the polyol resin component may include alkoxylated polyol resins derived from one or more of the following: synthetic diols, naturally occurring diols, polyamines, polycarboxylic acids, polyols having multiple hydroxyl functional groups, amino acids, and carbohydrates. It should be understood that the polyol resin component may include one or more polyol resins derived from C2-C5 epoxides or alkylene carbonates. As defined herein, “polyol resin” does not contain diepoxides or phenolic resins.

[0021] In one embodiment, the water-based demulsifier comprises between about 5% by weight and about 40% by weight of an acid-catalyzed alkoxylated alkylphenol resin, between about 5% by weight and about 40% by weight of an alkali-catalyzed alkoxylated alkylphenol resin, between about 1% by weight and about 30% by weight of a polyol resin, between about 1% by weight and about 10% by weight of a surfactant, between about 1% by weight and about 20% by weight of a hydrophilic binder, and between about 20% by weight and about 60% by weight of a base solvent.

[0022] In another embodiment, the water-based demulsifier comprises, between about 9% and about 15% by weight, an acid-catalyzed alkoxylated alkylphenol resin, between about 9% and about 20% by weight, a polyol resin, between about 16% and about 30% by weight, a surfactant, between about 2% and about 6% by weight, a hydrophilic binder, and a base solvent, between about 40% and about 60% by weight.

[0023] Several embodiments of the water-based demulsifier comprise a diepoxide resin. Suitable diepoxide resins are obtained by crosslinking at least one diepoxide with one or more polydiols or polyols.

[0024] In one embodiment, the diepoxide is present in an amount between about 8% by weight and about 15% by weight of the water-based demulsifier. For example, the water-based demulsifier may comprise between about 9% by weight and about 15% by weight of an acid-catalyzed alkoxylated alkylphenol resin, between about 9% by weight and about 20% by weight of an alkali-catalyzed alkoxylated alkylphenol resin, between about 8% by weight and about 15% by weight of the water-based demulsifier, between about 2% by weight and about 6% by weight of a surfactant, between about 1% by weight and about 20% by weight of a hydrophilic binder, and between about 40% by weight and about 60% by weight of a base solvent.

[0025] In some embodiments, the water-based demulsifier also comprises a wetting agent. The wetting agent may be present in the water-based demulsifier in an amount between about 1% by weight and about 10% by weight. In one embodiment, the water-based demulsifier comprises about 5% by weight of a wetting agent.

[0026] It should be understood that, as used herein, the range of X weight% to Y weight% will be interpreted as including the public content of every discrete integer value between X and Y (e.g., X, X+1, X+2 ... Y-1, Y).

[0027] Water-based demulsifiers can be used in desalting processes to break down emulsions in crude oil and wash water. In some embodiments, the water-based demulsifier can be applied at the desalter by injecting a treatment of the water-based demulsifier into the crude oil before it enters the desalter. In cases where the crude oil is relatively easy to process, injection into the oil phase may be desirable. In some embodiments, the water-based demulsifier can alternatively be injected into the wash water before it enters the desalter. In other embodiments, the water-based demulsifier can be injected into both the crude oil and the wash water. In other embodiments, the water-based demulsifier can be injected into the wash water as an adjunct to a different demulsifier injected into the oil phase to enhance overall performance by using two different products. In cases where the crude oil is not easily processed, it may be necessary to add the water-based demulsifier to the aqueous phase.

[0028] Example I

[0029] Electrostatic Desalination and Dehydration (EDDA) testing methods were used to simulate the desalination process in order to formulate and screen potential blends for water-based demulsifiers. The water-based demulsifiers tested included those with the following compositions: resins with the same acid catalysis, resins with the same base catalysis, surfactants, branched joints, and straight joints:

[0030]

[0031] For EDDA testing, West Texas Intermediate (WTI) crude oil was added to a Waring blender, followed by 5% deionized wash water to bring the total volume to 1. The coarse mixture was mixed at 60% speed for four (4) minutes on a variac mixer. The coarse mixture was then poured into EDDA tubes just below the 100 mL line and placed in an EDDA heating block heated to 120°C. For each test tube, except those designated as blank samples, 6 ppm of demulsifier was added. The screw-top electrode cap was then placed on each EDDA tube, and the sample was heated for approximately twenty-five (25) minutes. The tubes were then shaken 100 to 200 times and returned to the heating block for five (5) minutes. The electrode cap was placed on the EDDA tube and locked in place, ensuring good contact between the cap and electrode cap. The electrode was run at 1500 volts for five (5) minutes before the tube was pulled out. At this point, record the percentage of water droplets in each tube. Replace the electrode cap onto the EDDA tube and repeat the subsequent steps until the desired total residence time is achieved.

[0032] Example II

[0033] Dehydration tests were performed on certain samples from Example I to observe the amount of water and / or solids precipitated from each sample, record any emulsions, and obtain basic sediment and water (BS&W) data. The performance of these water-based demulsifiers from Example I was compared with the performance of three hydrocarbon-based products (designated as demulsifiers F, G, and H). For each sample in this test, except for the blank sample, a 12.5 mL centrifuge tube was filled to 50% mark with xylene and then filled with 5.8 mL of dehydrated WTI crude oil containing 4% wash water of one of the demulsifiers A, B, F, G, and H. The centrifuge tubes were centrifuged at 2000 rpm for four (4) minutes before the samples were observed.

[0034] As shown in the table below, approximately the same amount of water (in mL) precipitated in each of the demulsifiers A, B, F, G, and H over time. The amount of water precipitated in each sample was more than twice that of the blank sample without demulsifier.

[0035]

[0036] The interface and saline solution in each test tube were also observed. Both the sample with demulsifier A and the blank sample showed 2.5 mL of emulsion. The remaining samples showed 0.5 mL of emulsion and were slightly clear. Therefore, demulsifiers B, F, G, and H were better than demulsifier A in terms of demulsification.

[0037] Each sample (including blank samples) only shows trace amounts of BS&W.

[0038] Example III

[0039] Further tests were conducted to compare the performance of certain water-based demulsifiers from Example I (specifically, demulsifier B) against hydrocarbon-based products with the same activity and hydrocarbon-based demulsifier F. Samples were prepared as in Example I and subjected to the EDDA test method, with the following changes: WTI crude oil was replaced with a 3:1 mixture of WTI crude oil and West Texas Sour crude oil (WTI:WTS), and then 5% instead of 4% deionized wash water was used. Additionally, 8 ppm of demulsifier was added to each test tube instead of 6 ppm, except for the blank sample. The dehydration test of Example II was performed on each sample, and the results are as follows.

[0040] As shown below, the amount of water precipitated (in mL) by demulsifiers B and F is approximately the same over time. The amount of water precipitated by demulsifier B is greater than that of existing hydrocarbon products, and the same as that precipitated by demulsifier F. The amount of water precipitated by demulsifiers B and F over time also exceeds the amount observed in Example II using the same demulsifiers. Furthermore, the amount of water precipitated by both demulsifiers B and F is more than three times that of the blank sample without demulsifier.

[0041]

[0042] The blank sample contained 3.5 mL of emulsion and was slightly turbid. Samples with demulsifiers B and F each showed 0.5 mL of emulsion and were slightly turbid. In contrast, the existing hydrocarbon-based product was also slightly turbid, but showed only 2 mL of emulsion. Therefore, the sample with the water-based demulsifier B was significantly better than the existing hydrocarbon-based product in breaking down the emulsion into oil and aqueous phases. Demulsifier B also exhibited performance comparable to that of the hydrocarbon-based demulsifier F.

[0043] Samples containing demulsifiers B and F showed only trace amounts of BS&W. Existing hydrocarbon products and blank samples both showed 0.4% BS&W.

[0044] Example IV

[0045] Further tests were conducted to compare the performance of other water-based demulsifiers against hydrocarbon-based products. The water-based demulsifiers tested included those with the same acid-catalyzed resin, base-catalyzed resin, surfactant, branched joints, and straight joints, comprising the following components:

[0046]

[0047] The crude oil used in these tests was a 65:35 mixture of Caspian crude oil and WTI crude oil (Caspian:WTI), followed by 4.75% deionized wash water. Except for the blank sample, 8 ppm of demulsifier was added to each test tube. Dehydration tests were then performed on each sample according to Examples II and III, with the results shown below.

[0048] As shown in Table 5, for demulsifier I and the hydrocarbon-based product, the amount of water precipitated (in mL) was approximately the same over time. At most observed time intervals, the demulsifier J sample showed less water precipitation than the control sample. Demulsifier K experienced even less water precipitation over time; however, this demulsifier still performed significantly better than the control.

[0049]

[0050] Therefore, the sample with water-based demulsifier I is most comparable to existing hydrocarbon-based products in terms of breaking down the emulsion into oil and water phases.

[0051] The interface and brine of each sample were also observed. All samples had slightly turbid brine. The blank had 1.5 mL of emulsion, while the samples containing hydrocarbon products, demulsifier J, and demulsifier K all had 0.5 mL of emulsion. In contrast, demulsifier I showed only trace amounts of emulsion. Therefore, demulsifier I was the best in disrupting the emulsion in this crude oil. It should be understood that demulsifiers J and K can perform better than demulsifier I in different crude oils (e.g., heavier crude oils containing more solids).

[0052] Each sample (including blank samples) only shows trace amounts of BS&W.

[0053] In the foregoing description, the invention has been described with reference to specific embodiments thereof. However, it will be apparent that various modifications and changes may be made thereto without departing from the broader scope of the invention as set forth in the appended claims. Therefore, this specification should be considered exemplary rather than restrictive. For example, resins, hydrophilic connectors, surfactants, solvents, processing steps, proportions, dosages, temperatures, and amounts not specifically identified or described in this disclosure or evaluated in particular embodiments are still contemplated within the scope of the invention.

[0054] This invention may suitably include, consist of, or substantially consist of the disclosed elements, and may be practiced in the absence of any undisclosed elements. As used herein, the singular forms “an,” “a,” and “the” are intended to also include the plural forms unless the context clearly indicates otherwise. As used herein, the term “about” with respect to a given parameter includes the stated value and has a meaning determined by the context (e.g., it includes the degree of error associated with the measurement of the given parameter, i.e., ±5% of the stated value). As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed items. As used herein, the term “elevated temperature” refers to a temperature range above about 35°C.

Claims

1. A water-based demulsifier, said water-based demulsifier comprising: Two or more demulsifying resins selected from the group consisting of: acid-catalyzed alkoxylated alkylphenol resins, base-catalyzed alkoxylated alkylphenol resins, polyol resins, and diepoxide resins. Surfactants; Hydrophilic connectors; and The base solvent, wherein the base solvent is water.

2. The water-based demulsifier according to claim 1, wherein the surfactant is selected from the group consisting of: C8-C24 alcohol ethoxylates, alkyl diphenyl ether disulfonates, biosurfactants, and combinations thereof.

3. The water-based demulsifier according to claim 2, wherein the surfactant is a biosurfactant selected from the group consisting of glucosides, rhamnolipids, alkyl polyglycosides, sophorolipids, lecithin, lipopeptides, betaine, emulsifiers, and combinations thereof.

4. The water-based demulsifier according to claim 1, wherein the hydrophilic connector comprises a C3-C18 branched connector selected from the group consisting of branched alkyl alcohols, branched diols, branched alkyl glycerols, and combinations thereof.

5. The water-based demulsifier according to claim 4, wherein the hydrophilic connector further comprises a C1-C18 straight-chain connector selected from the group consisting of: straight-chain glycols, straight-chain alkyl alcohols, straight-chain alkyl glycerols, polymers, and combinations thereof.

6. The water-based demulsifier according to claim 5, wherein the C1-C18 straight linker is a polymer selected from the group consisting of: polyethylene glycol; polypropylene glycol; block copolymers having polyethylene glycol, polypropylene glycol, or both; random copolymers having polyethylene glycol, polypropylene glycol, or both; and combinations thereof.

7. The water-based demulsifier according to claim 1, wherein the two or more demulsifying resins include acid-catalyzed alkoxylated alkylphenol resins and base-catalyzed alkoxylated alkylphenol resins.

8. The water-based demulsifier according to claim 7, wherein the acid-catalyzed alkoxylated alkylphenol resin comprises a C4-C12 alkyl chain.

9. The water-based demulsifier according to claim 7, wherein the alkali-catalyzed alkoxylated alkylphenol resin comprises a C4-C12 alkyl chain.

10. The water-based demulsifier according to claim 7, wherein the water-based demulsifier comprises: Acid-catalyzed alkoxylated alkylphenol resins ranging from about 5% to about 40% by weight; Alkali-catalyzed alkoxylated alkylphenol resins ranging from about 5% to about 40% by weight; Surfactants ranging from about 1% to about 10% by weight; Hydrophilic connectors ranging from about 1% to about 20% by weight; and The base solvent is between about 20% by weight and about 60% by weight.

11. The water-based demulsifier according to claim 7, wherein the two or more demulsifying resins further comprise polyol resins.

12. The water-based demulsifier according to claim 11, wherein the polyol resin is an alkoxylated polyol resin derived from at least one of synthetic diols, naturally occurring diols, polyamines, polycarboxylic acids, amino acids, and carbohydrates.

13. The water-based demulsifier according to claim 11, wherein the water-based demulsifier comprises: Acid-catalyzed alkoxylated alkylphenol resins ranging from about 5% to about 40% by weight; Alkali-catalyzed alkoxylated alkylphenol resins ranging from about 5% to about 40% by weight; Polyol resins ranging from about 1% to about 30% by weight; Surfactants ranging from about 1% to about 10% by weight; Hydrophilic connectors ranging from about 1% to about 20% by weight; and The base solvent is between about 20% by weight and about 60% by weight.

14. The water-based demulsifier according to claim 7, wherein the two or more demulsifying resins further comprise a diepoxide resin obtained from one or more polydiols or polyols.

15. The water-based demulsifier according to claim 14, wherein the water-based demulsifier comprises: Acid-catalyzed alkoxylated alkylphenol resins ranging from about 9% to about 15% by weight; Alkali-catalyzed alkylphenol resins ranging from about 9% to about 20% by weight; Between about 8% by weight and about 15% by weight of a diepoxide resin; Surfactants ranging from about 2% C to about 6% C; Hydrophilic connectors ranging from about 1% to about 20% by weight; and The base solvent is between about 40% by weight and about 60% by weight.

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