WO2018067679A1

WO2018067679A1 - Methods of making and using heat exchangers

Info

Publication number: WO2018067679A1
Application number: PCT/US2017/055100
Authority: WO
Inventors: S. M. Ibrahim Al-Rafia; Mohit Malik; Teresa J. PENA-BASTIDAS; Bethany A. TUROWEC
Original assignee: 3M Innovative Properties Co
Current assignee: 3M Innovative Properties Co
Priority date: 2016-10-04
Filing date: 2017-10-04
Publication date: 2018-04-12
Anticipated expiration: 2019-04-04

Abstract

A method of making at least a portion of a heat exchanger includes coating at least the portion of the heat exchanger with a composition containing hydrophilic nanoparticles and water. A method of at least one of heating or cooling a fluid that contains a hydrocarbon includes introducing the fluid comprising the hydrocarbon to a heat exchanger. At least a portion of the heat exchanger has a coating including hydrophilic nanoparticles. Also provided is a heat exchanger. At least a portion of the heat exchanger has a coating including hydrophilic nanoparticles. The heat exchanger itself or used in the methods is useful for at least one of heating or cooling a fluid comprising a hydrocarbon.

Description

METHODS OF MAKING AND USING HEAT EXCHANGERS BACKGROUND

Heat exchangers are widely used in industry. In the oil industry, certain produced fluids require cooling (e.g., those coming from steam injection recovery processes). For example, water from a steam injection recovery process needs to be cooled before it is treated. The water (with or without chemical addition) is usually reinjected into the reservoir after treatment. Other produced fluids require heating. For example, increasing the temperature is a necessary step for emulsion separation, oil and water treatment, and crude oil upgrading. Crude oil is treated such that the water and solids concentrations reach a level that allows for upgrading, and the oil has to be heated to proceed to its upgrading.

Each one of these applications presents challenges for heat exchangers. Fouling, scaling, and corrosion on the internal surfaces of heat exchangers may occur. The material deposited on the heat exchanger's internal surface may be mineral deposits (e.g., present in the water), oil, polymer (e.g., in the case of a polymer injection Enhanced Oil Recovery (EOR) process), or a combination thereof.

Fouling and scaling reduce the heat transfer efficiency of surfaces and necessitate the use of higher temperatures to compensate for the lost heat exchange rates. Use of higher temperatures not only increases the overall cost of the processes but also can cause degradation of the expensive polymers used for polymer flooding. Particularly in fire tube heat exchangers, hot points are created due to uneven material deposition on the tubes, and the tubes get damaged and require advanced replacement. Also, corrosion is propitiated under the fouling material possibly due to ion accumulation. Therefore, maintenance costs due to fouling, scaling, and corrosion are large components of working capital in the oil industry for several oil recovery processes like SAGD (Steam-Assisted Gravity Drainage), CSI (Cyclic Steam Injection), and polymer flooding.

In unrelated technologies, nanoparticles have been used in some applications to provide anti-fouling or easy -to-clean surfaces. Functionalized silicate nanoparticles have been reported as useful for removing asphaltene particles from a substrate in U.S. Appl. Publ. No. 2015/0191646 (Mazyar et al.). A coating composition consisting of hydrophilic silica nanoparticles and hydrophobic fluorine resin particles is described in U.S. Pat. No. 8,448,697 (Morioka et al.) and U.S. Appl. Publ. No. US 2015/0241146 (Yoshida et al.) as a useful anti-fouling coating for heat exchangers in air conditioners. Zirconium chloride or zirconyl chloride is added to the coating in U.S. Appl. Publ. No. US 2015/0241146 to prevent the adhesion of metal particles. Compositions containing nanoparticles are reported to facilitate removal of a bitumen-containing mud from a substrate in Int. Appl. Pub. No. WO2015/171477 (Van Bommel et al.).

SUMMARY

Oil and gas companies use plate heat exchangers, for example, to adjust the temperature of heavy oil and bitumen emulsions. Use of heat exchangers allows for efficient heat recovery and minimizes energy consumption. Increasing process heat transfer efficiency delivers immediate and significant cost savings. However, as a bitumen emulsion contacts the heat exchanger, some of its components can foul onto the plates due to temperature fluctuations, transport velocity, and nature of the oil emulsion. Since SAGD and many EOR operations require a high degree of heat transfer efficiency, gradual formation of a foulant layer on the surface of heat exchangers significantly reduces overall operational efficiency. Costs associated with heat exchanger fouling include production losses due to efficiency deterioration and loss of production during planned or unplanned shutdowns and maintenance costs resulting from the removal of fouling deposits with chemicals and/or mechanical antifouling devices or the replacement of corroded or plugged equipment. In a typical SAGD operation roughly 10 to 15% of maintenance cost of a process plant can be attributed to the fouling related problems. Typically, cleaning costs are in the range of $400,000 to $500,000 per heat exchanger per cleaning. In many instances, heat exchangers require monthly cleaning. Corrosion may also occur in the metal surfaces under the fouled areas.

Coatings including hydrophilic nanoparticles useful in the methods and heat exchanger according to the present disclosure can typically inhibit foulant deposition the coated portion of the heat exchanger. In some embodiments, any foulant that adheres to at least the portion of the heat exchanger that is coated with the nanoparticles may be more easily removed than from an uncoated portion of the heat exchanger. Such an easy-to-clean feature could significantly reduce cleaning time of heat exchangers.

In one aspect, the present disclosure provides a method of making at least a portion of a heat exchanger. The method includes coating at least the portion of the heat exchanger with a composition containing hydrophilic nanoparticles and water. The heat exchanger is useful for at least one of heating or cooling a fluid comprising a hydrocarbon.

In another aspect, the present disclosure provides a heat exchanger. At least a portion of the heat exchanger has a coating including hydrophilic nanoparticles.

In another aspect, the present disclosure provides a method of at least one of heating or cooling a fluid that contains a hydrocarbon. The method includes introducing the fluid comprising the hydrocarbon to a heat exchanger. At least a portion of the heat exchanger has a coating including hydrophilic nanoparticles. Further features will be described or will become apparent in the course of the following detailed description. It should be understood that each feature described herein may be utilized in any combination with any one or more of the other described features, and that each feature does not necessarily rely on the presence of another feature except where evident to one of skill in the art.

In this application, terms such as "a", "an" and "the" are not intended to refer to only a singular entity, but include the general class of which a specific example may be used for illustration. The terms "a", "an", and "the" are used interchangeably with the term "at least one". The phrases "at least one of and "comprises at least one of followed by a list refers to any one of the items in the list and any combination of two or more items in the list. All numerical ranges are inclusive of their endpoints and integral and non-integral values between the endpoints unless otherwise stated (e.g. 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5).

"Hydrophilic" describes nanoparticles that are wettable by aqueous liquids (i.e., liquids comprising water) in contact with the surfaces. Wettability can be measured by contact angle of the liquid on a surface. Typically, a surface or coating is hydrophilic when the contact angle of water on the surface or coating is less than 90 °.

"Hydrophobic" describes surfaces or coatings that are nonwettable by aqueous liquids (i.e., liquids comprising water) in contact with the surfaces or coatings. Typically, a surface is hydrophobic when the contact angle of water on the surface is about 90 ⁰ or greater. DETAILED DESCRIPTION

In the composition including hydrophilic nanoparticles and water and the coating comprising hydrophilic nanoparticles, the nanoparticles can comprise at least one of silica nanoparticles, alumina nanoparticles, titania nanoparticles, or alumina coated silica nanoparticles. The shape of the nanoparticles is not limited and can be any shape, regular or irregular. In some embodiments, the nanoparticles comprise at least one of fumed silica or colloidal silica. In some embodiments, the nanoparticles comprise spherical silica nanoparticles.

The composition useful for coating at least a portion of the heat exchanger may comprise an aqueous dispersion comprising at least about 0.001 weight percent (wt%), at least about 0.01 wt%, at least about 0.02 wt %, at least about 1 wt% or at least about 2 wt% nanoparticles up to about 55 wt%, up to about 50 wt%, up to about 45 wt%, up to about 20 wt%, up to about 15 wt%, or up to about 10 wt% nanoparticles. In some embodiments, composition comprising nanoparticles and water may comprise at least about 10 wt%, at least about 15 wt%, or at least about 20 wt% nanoparticles, up to about 45 wt%, up to about 50 wt% or up to about 55 wt% nanoparticles. As used herein, weight percent refers to the weight based on total weight of the composition. In some embodiments, the coating composition comprises between about 1 wt% and about 25 wt% nanoparticles.

Silica nanoparticles useful in compositions of the present disclosure may have a volume average particle diameter of up to about 300 nanometer (nm), up to about 150 nm, or up to about 60 nm. In some embodiments, the silica nanoparticles are spherical silica particles having a volume average particle diameter in a range of from 2 nm to 100 nm or 2 nm to 60 nm. The silica particles may have any particle size distribution consistent with the above 60 nm volume average particle diameter. For example, the particle size distribution may be monomodal or polymodal (e.g. bimodal).

In some embodiments, the nanoparticles may comprise a mixture of nanoparticles having different average particle diameters. In some embodiments, the mixture of nanoparticles may comprise at least about 50% spherical silica nanoparticles having an average particle diameter of between about 50 nanometers and about 70 nanometers, and up to about 50% spherical silica nanoparticles having an average particle diameter of less than about 10 nanometers.

In some embodiments, the composition comprising nanoparticles and water comprises between about 1 wt% and about 25 wt% spherical silica nanoparticles having an average particle diameter of up to about 300, up to about 150, or up to about 60 nanometers.

Spherical silica particles in aqueous media, which may also be referred to as sols or colloidal silica, are known in the art and are available commercially. For example, silica sols in water are available under the trade designations NALCO™ from Nalco Chemical Co., Naperville, II. One useful silica sol with a volume average particle size of 60 nm is available as NALCO™ 1060 from Nalco Chemical Co. Another useful commercially available silica sol is available as NALCO™ 1115 with a volume average particle diameter of 4 nm. The spherical silica nanoparticles can comprise a mixture of nanoparticles having different average particle diameters, for example, a mixture of about 50% spherical silica nanoparticles having an average particle diameter of 60 nanometers and about 50% spherical silica nanoparticles having an average particle diameter of 4 nanometers. Silica nanoparticles are further described in United States Patent Publication 2012/0029141 published February 2, 2012, the entire contents of which are herein incorporated by reference.

Other useful nanoparticle materials include LUDOX-CL and LUDOX HS-40 colloidal silica available from W.R. Grace & Co., Columbia, Maryland, AERODISP 740X fumed titanium dioxide available from Evonik Industries AG, Essen, Germany, and NYACOL AL25 colloidal alumina available from Nyacol Nano Technologies, Inc., Ashland, MA.

In some embodiments, the composition useful for coating at least a portion of the heat exchanger further comprises surfactant. Examples of suitable surfactants include cationic surfactants, nonionic surfactants, anionic surfactants, amphoteric surfactants, and combinations thereof. The composition comprising nanoparticles and water may include at least about 0.001 wt%, at least about 0.01 wt%, or at least about 0.02 wt% surfactant up to about 2 wt%, up to about 1.5 wt%, or up to about 1 wt% surfactant.

Examples of suitable anionic surfactants include those with molecular structures comprising

(1) at least one hydrophobic moiety, such as from about C6 to about C20 alkyl, alkylaryl, and/or alkenyl groups, and (2) at least one anionic group and/or salts of such anionic groups. Suitable salts include sulfate, sulfonate, phosphate, polyoxyethylene sulfate, polyoxyethylene sulfonate, polyoxyethylene phosphate, and carboxylate salts. The salts can include alkali metal salts, ammonium salts, tertiary amino salts. Representative commercial examples of useful anionic surfactants include sodium lauryl sulfate, available under the trade name TEXAPON L-100 from Henkel Inc., Wilmington, Del, sodium dodecylbenzenesulfonate, dioctyl ester of sodium sulfosuccinic acid, polyethoxylated alkyl (C 12) ether sulfate, ammonium salt, and salts of aliphatic hydrogen sulfates. In some embodiments, the surfactant comprises sodium dodecyl sulfate (CH₃(CH₂)nOS0₃Na).

Suitable nonionic surfactants include block copolymers of polyethylene glycol and polypropylene glycol, polyoxyethylene (7) lauryl ether, polyoxyethylene (9) lauryl ether, polyoxyethylene (18) lauryl ether, and polyethoxylated alkyl alcohols such as Surfynol SE-F, available from Air Products and Chemicals Inc., Allentown, PA.

Suitable cationic surfactants include alkyldimethylbenzylammonium chlorides, di- tallowdimethyl-ammonium chloride, and cetyltrimethylammonium bromide, available from Sigma Aldrich, St. Louis, MO.

Suitable amphoteric surfactants include N-coco-aminopropionic acid.

Silicone surfactants and fluorochemical surfactants such as those available under the trade designation FLUORAD (available from 3M Company of St. Paul, Minn.) may also be useful.

In some embodiments, the composition comprising hydrophilic nanoparticles and water has a pH in a range from about 1 to about 12. In some embodiments, the pH of the composition is at least about 2 or at least about 3. In some embodiments, the pH of the composition is up to about 10, up to about 9, or up to about 6. The coating composition may optionally include sufficient acid to adjust the pH to a range of about 1 to 12, 2 to 10, or about 3 to 9. Suitable acids include inorganic acids such as phosphoric acid (H₃P0₄), H₂S0₃, HC1, HBr, HI, HBr0₃, HN0₃, HC10₄, and H₂S0₄. Suitable acids also include organic acids such as citric acid, oxalic acid, CH₃S0₃H, CF₃S0₃H, and CE SC OH. In some embodiments, the acid is selected from the group consisting of HC1, HN0₃, H2SO4, H₃P04, and combinations thereof. In some embodiments, the acid may be present in the composition comprising hydrophilic nanoparticles and water in an amount ranging from about 0.05 wt% to about 0.15 wt%. While the presence of an acid to lower the pH is desirable for many applications, a surprisingly effective coating can be made without the addition of acid.

In some embodiments, the hydrophilic nanoparticles comprise at least one of fumed silica or colloidal silica, the nanoparticles are spherical nanoparticles present in an amount of about 2 wt% to 15 wt%, based on the total weight of the composition comprising nanoparticles and water, and the surfactant is sodium dodecyl sulfate present in an amount of about 0.01 wt% to 1 wt%, based on the total weight of the composition comprising nanoparticles and water.

The composition comprising hydrophilic nanoparticles and water and the coating comprising hydrophilic nanoparticles may include other optional additives such as binders (e.g., inorganic binders and organic polymer binders), rheological modifiers, corrosion inhibitors, silanes, and phosphates. Likewise, a coating comprising hydrophilic nanoparticles in the method and heat exchanger disclosed herein can include any of these optional additives.

Examples of suitable organic polymer binders include hydrophilic polymers such as poly(ethylene glycol) (PEG), poly(vinyl alcohol) (PVA), poly aery lie acid, maleic/olefin copolymer, acrylic/maleic copolymer, polymethacrylic acid, acrylic acid-methacrylic acid copolymers, hydrolyzed polyacrylamide, hydrolyzed polymethacrylamide, hydrolyzed polyamide- methacrylamidecopolymers, hydrolyzed polyacrylonitrile, hydrolyzed polymethacrylonitrile, hydrolyzed acrylonitrile-methacrylonitrile copolymers, acrylic acid-co-acrylamido-2 methyl propane sulfonate, latexes that include polyurethane dispersions, and combinations thereof. The weight ratio of the hydrophilic nanoparticles to the organic polymer binder is generally at least about 1: 1, and in some embodiments, it ranges from 2: 1 to 9: 1; 4: 1 to 8: 1, or 5: 1 to 7: 1.

Examples of suitable inorganic binders include sodium aluminate, aluminum bromide, aluminum chlorate, aluminum chloride, aluminum iodide, aluminum nitrate, aluminum sulfate, aluminum acetate, aluminum formate, aluminum tartrate, aluminum lactate, aluminum oleate, aluminum bromate, aluminum borate, aluminum potassium sulfate, aluminum zinc sulfate, aluminum phosphate, zinc chloride, zinc sulfate, zinc nitrate, zinc iodide, zinc thiocyanate, zinc fluorosilicate, zinc dichromate, zinc chlorate, sodium zincate, zinc gluconate, zinc acetate, zinc benzoate, zinc citrate, zinc lactate, zinc formate, zinc bromate, zinc bromide, zinc fluoride, zinc fluosilicate, zinc salicylate, and combinations thereof. The weight ratio of the hydrophilic nanoparticles to the inorganic binder is generally at least about 1 : 1, and in some embodiments, it ranges from 2: 1 to 9: 1; 4: 1 to 8: 1, or 5: 1 to 7: 1.

Examples of suitable rheology modifiers include hydrophobically modified ethylene oxide urethane (HEUR), cellulosics, clays, and combinations thereof.

Examples of suitable corrosion inhibitors include aluminum nitrate, zinc salts (e.g., zinc phosphate), manganese salts, chromate salts, barium salts, nitrites, nitrates, phosphosilicates, borates, borosilicates, 2-phosphonobutane-l,2,4-tricarboxylic acid tetrasodium salt (available, for example, under the trade designation "BAYHIBIT S GRANULATE" from Bayhibit), 2- phosphonobutane-l,2,4-tricarboxylic acid (available, for example, under the trade designation "BAYHIBIT AM" from Bayhibit), cocoamphomonoacetate (available, for example, under the trade designation "TEGO CI-231" from Evonik), and di (nortallowyloxy ethyl) dimethylammonium chloride (available, for example, under the trade designation "TEGO CI- 112" from Evonik). Other examples of suitable corrosion inhibitors include those obtained from Halox under the trade designations "HALOX 550", "HALOX 550WF", "HALOX 570", and "HALOX SZP-391JM", "HALOX 515 LFG" and those obtained from Evonik under the trade designations "TEGO CI-511", "TEGO CI 351", TEGO CI-471", "TEGO CI-451", and "TEGO CI-121". Combinations of any of these corrosion inhibitors may also be useful.

Examples of suitable silanes include zwitterionic silanes (e.g., those have an ammonium and a sulfonate group such as those described in U.S. Pat. Appl. Pub. No. 2013/0164730

(Gustafson et al.)), hydroxyl sulfonate silanes (e.g., those described in U.S. Pat. Appl. Pub. No. 2013/0164730 (Gustafson et al.)), phosphonate silanes, carboxylate silanes, polyhydroxyl alkyl, hydroxyl polyethyleneoxide silanes, polyethyleneoxide silanes, and combinations thereof. Other examples of suitable silanes include 3-(trihydroxysilyl)propyl methylphosphonate, a carboxylated trimethoxysilane (e.g., TMSEDTA), N-[3-(trimethoxysilyl)propyl]ethylenediamine, l-[3- (trimethoxysilyl)propyl]urea, acetoxypropyltrimethoxysilane, and combinations thereof.

While in some applications, it may be desirable to include hydrophobic particles in combination with hydrophilic nanoparticles, in the methods disclosed herein, we have found that hydrophilic nanoparticles provide better antifouling performance when exposed to a liquid including hydrocarbons than hydrophobic coatings. Accordingly, in some embodiments, the composition according to the present disclosure including nanoparticles and water is substantially free of particles of fluorinated resin. The term "substantially free" in this regard refers to including less than 5%, 4%, 3%, 2%, or 1% by weight of particles of fluorinated resin, based on the total weight of the fluorinated resin and nanoparticles. "Substantially free" of particles of fluorinated resin can also mean free of particles of fluorinated resin. A person skilled in the art would understand what is meant by the term "fluorinated resin". Examples of such resins include PTFE (polytetrafluoroethylene), FEP (copolymer of tetrafluoroethylene and hexafluoropropylene), PFA (copolymer of tetrafluoroethylene and perfluoro alkyl vinyl ether), ETFE (copolymer of ethylene and tetrafluoroethylene), ECTFE(copolymer of ethylene and chlorotrifluoroethylene), PVDF (polyvinylidene-fluoride), PCTFE (polychlorotrifluoroethylene), and PVF (polyvinyl-fluoride).

While in some applications, it may be desirable to include zirconium chloride or zirconyl chloride in a composition comprising nanoparticles, in the methods disclosed herein, we have found that hydrophilic nanoparticles provide excellent antifouling performance when exposed to a liquid including hydrocarbons even in the absence of such zirconium salts. Accordingly, in some embodiments, the composition according to the present disclosure including nanoparticles and water is substantially free of zirconium chloride and zirconyl chloride. The term "substantially free" in this regard refers to including less than 5%, 4%, 3%, 2%, or 1% by weight of zirconium chloride or zirconyl chloride, based on the total weight of the zirconium compound and nanoparticles. "Substantially free" of zirconium chloride or zirconyl chloride can also mean free of zirconium chloride or zirconyl chloride. In some embodiments, the composition according to the present disclosure including nanoparticles and water is substantially free of zirconium salts.

Hydrophilic nanoparticles are those which have surface OH groups. In some embodiments, the hydrophilic nanoparticles are not surface modified. For example, it is not desirable for the nanoparticles useful in the methods disclosed herein to be surface modified with any group more hydrophobic than an OH surface group. Hydrophobic groups such as alkyl and aryl groups, if covalently attached to the surface of the nanoparticles are expected to be detrimental to the anti- fouling behavior of the coating in the methods disclosed herein. See, for example, Counter Examples 8 and 9 and the results in Table 5, below.

Methods according to the present disclosure can include coating at least a portion of a heat exchanger to provide a coating comprising hydrophilic nanoparticles on the heat exchanger. Coating the portion of the heat exchanger may be accomplished by conventional methods, for example, at least one of spray coating, brushing, rolling, dipping, or pouring. In some embodiments, coating at least a portion of the heat exchanger is carried out by spraying the composition comprising hydrophilic nanoparticles and water. The composition may be coated on the portion of the heat exchanger when the substrate is wet or dry. Coating the composition on a wet substrate has the advantages that pre-drying of the substrate is not required and that the composition more readily spreads across the surface of the substrate, both of which reduce working time. The composition may be dried after application to the portion of the heat exchanger. In these embodiments, methods of the present disclosure include removing at least a portion of the water to provide a dried coating comprising hydrophilic nanoparticles. Despite comprising a large amount of water, the composition typically dries remarkably quickly. Typically, the coatings are dried at ambient or warm temperatures without the need for high temperature heat, radiation, or other curing methods. In other embodiments, the coating may be dried at temperatures of between 20 °C and 150 °C, for example, in a recirculating oven, in which an inert gas may be circulated. Elevated temperature may speed the drying process.

In a method of making at least a portion of a heat exchanger, the composition comprising hydrophilic nanoparticles and water may be coated onto the portion of the heat exchanger when the heat exchanger is manufactured or just before use of the heat exchanger in the field. Compositions comprising hydrophilic nanoparticles and water may have average wet thickness varying from 0.5 to 50 micrometers, in some embodiments, 1 to 10 micrometer, when they are applied to at least a portion of the heat exchanger. Coatings comprising hydrophilic nanoparticles useful for practicing the present disclosure are can quite thin (e.g., typically less than 1 micrometer thick).

The composition comprising hydrophilic nanoparticles and water is applied to at least a portion of a heat exchanger in the method described herein. Therefore, at least the portion of the heat exchanger has a coating comprising hydrophilic nanoparticles in the method and heat exchanger disclosed herein. A heat exchanger is a device for transferring the heat of one fluid to another fluid. While in some heat exchangers, the fluids are in direct contact, in many heat exchangers, a solid barrier separates the fluids. The portion of the heat exchanger that is coated in the methods and article described herein can be a solid barrier between the two fluids. Heat exchangers usually maximize the transfer of heat by maximizing the contact surface area between fluids, as when the warmer fluid is passed through a series of coils or thin plates. Thus, in some embodiments, the portion of the heat exchanger that is coated is a coil, tube, or plate. Plates useful in heat exchangers may be flat, corrugated, or have a surface pattern (e.g., a chevron pattern). In some embodiments, the portion of the heat exchanger that is coated comprises a metal surface. The portion of the heat exchanger may comprise at least one of steel, carbon steel, stainless steel, titanium alloys, or copper, for example.

The heat exchanger according to the present disclosure or made or used in the methods of the present disclosure is used for at least one of heating or cooling a fluid comprising a hydrocarbon. The hydrocarbon in the fluid may comprise at least one of bitumen or heavy oil. Bitumen is a naturally occurring viscous mixture of hydrocarbons with a consistency of molasses and an America Petroleum Institute (API) gravity of 8-14. Bitumen molecules contain thousands of carbon atoms. This makes bitumen one of the most complex molecules found in nature. On average, bitumen is composed of about 83.2% carbon, 10.4% hydrogen, 0.94% oxygen, 0.36% nitrogen, and 4.8% sulfur. Heavy oil is defined as a crude oil with high viscosity (typically above 200 cP), and gravity lower than 20° API. The fluid comprising a hydrocarbon in the methods according to the present disclosure may further comprise at least one of water, chemicals used for enhanced oil recovery (EOR) (e.g., polymers, surfactants, viscoelastic surfactants, polyacrylamides, modified polyacrylamides, xanthan gum/biopolymer, super adsorbent polymer composites, or alkali), ions present in the reservoir (e.g., calcium, magnesium , sodium, iron), demulsifiers, or solvents. In some embodiments, the portion of the heat exchanger with the coating comprising hydrophilic nanoparticles is in contact with the fluid comprising hydrocarbon. Alternatively or additionally, the portion of the heat exchanger having the coating comprising hydrophilic nanoparticles in contact with the coolant.

The coating comprising hydrophilic nanoparticles can often provide an anti-fouling property to at least a portion of a heat exchanger (e.g., a heat exchanger plate) used for at least one of heating or cooling a composition comprising hydrocarbons. As shown in the Examples, below, uncoated plates typically gained at least 2, 3, or 4 times more foulant as compared to coated plates when exposed to a heavy oil emulsion at 50 °C and 80 °C. The coatings described herein have also been found to assist in the removal of foulant from a portion of a heat exchanger to which the foulant becomes adhered. Accordingly, in some embodiments of the methods according to the present disclosure, the method includes removing at least the portion of the heat exchanger (e.g., heat exchanger plate) and removing foulant adhered to at least the portion of the heat exchanger. As shown in the Examples, below, the percentage of foulant removed from a plate coated according to the present disclosure is typically 2, 3, 4, 5, or times more the percentage of foulant removed from an uncoated plate.

The foulant may be removed from the substrate using water, organic solvent, an aqueous detergent, or combinations thereof. The aqueous detergent may be a terpene-based cleaner, citrus cleaner, or delimer. A suitable terpene-based detergent may comprise an aqueous mixture of terpene hydrocarbons, glycol, and nonionic surfactant in water, for example <10 wt% terpene hydrocarbons, <15 wt% glycol and <10 wt% nonionic surfactant blend in water, with the wt% based on total weight of the aqueous detergent. Such a detergent is commercially available as MEGASOL™ from Biosol™, Calgary, Alberta, Canada. In one embodiment, the silica-based composition and the aqueous terpene-based detergent may be blended to form a cleaning composition. The aqueous detergent may be also mixed with the composition comprising nanoparticles and water that is coated on the portion of the heat exchanger.

In some embodiments, cleaning the foulant from the coated portion of the heat exchanger

(e.g., heat exchanger plate) involves soaking the fouled portion in a pool of at least one of water, organic solvent or aqueous detergent. In some embodiments, cleaning the foulant from the coated portion of the heat exchanger (e.g., heat exchanger plate) involves spraying or rinsing the fouled portion with at least one of water, organic solvent, or aqueous detergent. The aqueous detergent may be as described in any of the above embodiments. The spray washing process may be accomplished in a single step process using a relatively high pressure spray (e.g. at least 100 psi), or the spray washing process may be accomplished in a two-step process using a first low pressure wash (e.g. less than about 50 psi), optionally followed by a soak, followed by a second low pressure wash. To conserve aqueous detergent, a high pressure spray method may be useful. Multiple high- pressure spray washings may be useful in difficult cases. In some circumstances, such as after the heat exchanger has already seen service in the field, a portion of a heat exchanger may first be cleaned to remove foulant, and the composition comprising nanoparticles and water applied subsequently. In other circumstances, it may be beneficial to apply the composition comprising hydrophilic nanoparticles and water simultaneously with cleaning the portion of the heat exchanger to remove foulant. In these cases, it may be useful to include aqueous detergent in the composition comprising nanoparticles. It also may be useful to apply the composition comprising nanoparticles and water and an aqueous detergent composition to a fouled heat exchanger portion simultaneously in two in separate streams.

In some embodiments, a coating comprising hydrophilic nanoparticles may last for at least one, two, three, or more cleanings to remove foulant from the portion of the heat exchanger, depending on the end use conditions. After this time, the composition comprising nanoparticles and water may be reapplied to the substrate. Depending on the working life of coating comprising hydrophilic nanoparticles, the composition comprising nanoparticles and water may be applied during or after each cleaning to remove foulant or during or after two or more cleanings. A cycle of cleaning and application of the composition comprising hydrophilic nanoparticles and water may be established.

Some Embodiments of the Disclosure

In a first embodiment, the present disclosure provides a method of making at least a portion of a heat exchanger, the method comprising coating at least the portion of the heat exchanger with a composition comprising hydrophilic nanoparticles and water, wherein the heat exchanger is used for at least one of heating or cooling a fluid comprising a hydrocarbon.

In a second embodiment, the present disclosure provides the method of the first embodiment, wherein the composition comprises 1 to 25 percent by weight nanoparticles, based on the total weight of the composition.

In a third embodiment, the present disclosure provides the method of the first or second embodiment, wherein the composition further comprises surfactant.

In a fourth embodiment, the present disclosure provides the method of any one of the first to third embodiments, wherein the composition further comprises at least one of a nonionic, cationic, anionic, or amphoteric surfactant.

In a fifth embodiment, the present disclosure provides the method of any one of the first to fourth embodiments, wherein the composition comprises sodium dodecyl sulfate.

In a sixth embodiment, the present disclosure provides the method of any one of the first to fifth embodiments, wherein the composition has a pH from about 1 to about 12. In a seventh embodiment, the present disclosure provides the method of any one of the first to sixth embodiments, wherein the composition further comprises at least one of an organic acid or inorganic acid.

In an eighth embodiment, the present disclosure provides the method of any one of the first to seventh embodiments, wherein the composition further comprises phosphoric acid.

In a ninth embodiment, the present disclosure provides the method of any one of the first to eighth embodiments, wherein the composition further comprises an organic polymeric binder.

In a tenth embodiment, the present disclosure provides the method of any one of the first to ninth embodiments, wherein the composition further comprises an inorganic polymeric binder.

In an eleventh embodiment, the present disclosure provides the method of any one of the first to tenth embodiments, wherein the composition further comprises a corrosion inhibitor.

In a twelfth embodiment, the present disclosure provides the method of any one of the first to eleventh embodiments, wherein the composition further comprises at least one of a rheological modifier, a silane, or a phosphate.

In a thirteenth embodiment, the present disclosure provides the method of any one of the first to twelfth embodiments, wherein the composition is substantially free of particles of fluorinated resin.

In a fourteenth embodiment, the present disclosure provides the method of any one of the first to twelfth embodiments, wherein the composition is substantially free of zirconium salts.

In a fifteenth embodiment, the present disclosure provides a method of at least one of heating or cooling a fluid comprising a hydrocarbon, the method comprising introducing the fluid comprising the hydrocarbon to a heat exchanger, and at least one of heating or cooling the fluid comprising hydrocarbon, wherein at least a portion of the heat exchanger has a coating comprising hydrophilic nanoparticles.

In a sixteenth embodiment, the present disclosure provides the method of the fifteenth embodiment, further comprising removing at least the portion of the heat exchanger and removing foulant adhered to at least the portion of the heat exchanger.

In a seventeenth embodiment, the present disclosure provides the method of the sixteenth embodiment, wherein removing foulant adhered to at least the portion of the heat exchanger comprises rinsing at least the portion of the heat exchanger with water.

In an eighteenth embodiment, the present disclosure provides the method of the sixteenth or seventeenth embodiment, wherein removing foulant adhered to at least the portion of the heat exchanger comprises rinsing at least the portion of the heat exchanger with at least one of organic solvent or aqueous detergent. In a nineteenth embodiment, the present disclosure provides the method of any one of the first to eighteenth embodiments, wherein any foulant that adheres to at least the portion of the heat exchanger that is coated with the hydrophilic nanoparticles may be more easily removed than from a portion of the heat exchanger that is not coated with hydrophilic nanaoparticles.

In a twentieth embodiment, the present disclosure provides a heat exchanger, wherein at least a portion of the heat exchanger has a coating comprising hydrophilic nanoparticles, and wherein the heat exchanger is used for at least one of heating or cooling a fluid comprising a hydrocarbon.

In a twenty -first embodiment, the present disclosure provides the method or heat exchanger of any one of the fifteenth to twentieth embodiments, wherein the coating further comprises an organic polymeric binder.

In a twenty-second embodiment, the present disclosure provides the method or heat exchanger of any one of the fifteenth to twenty-first embodiments, wherein the coating further comprises an inorganic polymeric binder.

In a twenty -third embodiment, the present disclosure provides the method or heat exchanger of any one of the fifteenth to twenty-second embodiments, wherein the coating further comprises a corrosion inhibitor.

In a twenty-fourth embodiment, the present disclosure provides the method or heat exchanger of any one of the fifteenth to twenty -third embodiments, wherein the coating further comprises at least one of a rheological modifier, a silane, or a phosphate.

In a twenty -fifth embodiment, the present disclosure provides the method or heat exchanger of any one of the fifteenth to twenty -fourth embodiments, wherein the coating is substantially free of particles of fluorinated resin.

In a twenty-sixth embodiment, the present disclosure provides the method or heat exchanger of any one of the fifteenth to twenty -fifth embodiments, wherein the coating is substantially free of zirconium salts.

In a twenty -seventh embodiment, the present disclosure provides the method or heat exchanger of any one of the first to twenty-sixth embodiments, wherein the hydrophilic nanoparticles comprise at least one of silica nanoparticles, alumina nanoparticles, titania nanoparticles, alumina coated silica nanoparticles, or fumed silica nanoparticles.

In a twenty-eighth embodiment, the present disclosure provides the method or heat exchanger of any one of the first to the twenty -seventh embodiments, wherein the nanoparticles comprise colloidal silica.

In a twenty -ninth embodiment, the present disclosure provides the method or heat exchanger of any one of the first to the twenty -eighth embodiments, wherein the nanoparticles are spherical silica nanoparticles. In a thirtieth embodiment, the present disclosure provides the method or heat exchanger of the twenty -eighth or twenty-ninth embodiments, wherein the silica nanoparticles have an average diameter of less than about 300 nanometers.

In a thirty -first embodiment, the present disclosure provides the method or heat exchanger of any one of the twenty -eighth to thirtieth embodiments, wherein the silica nanoparticles comprise a mixture of nanoparticles having different average particle diameters.

In a thirty-second embodiment, the present disclosure the method or heat exchanger of the thirty-first embodiment, wherein the mixture of nanoparticles comprises greater than about 50% spherical silica nanoparticles having an average particle diameter of between about 50 nanometers and about 70 nanometers, and less than about 50% spherical silica nanoparticles having an average particle diameter of less than about 10 nanometers.

In a thirty -third embodiment, the present disclosure provides the method or heat exchanger of any one of the first to thirty-second embodiments, wherein at least the portion of the heat exchanger comprises a metal surface.

In a thirty -fourth embodiment, the present disclosure provides the method or heat exchanger the thirty -third embodiment, wherein the metal surface comprises at least one of steel, carbon steel, stainless steel, titanium alloys, or copper.

In a thirty -fifth embodiment, the present disclosure provides the method or heat exchanger of any one of the first to thirty -fourth embodiments, wherein the hydrocarbon comprises at least one of bitumen or heavy oil.

In a thirty-sixth embodiment, the present disclosure provides the method or heat exchanger of any one of the first to thirty-fifth embodiments, wherein the fluid comprising a hydrocarbon further comprises at least one of water, a polymer, a surfactant, calcium ion, magnesium ion, sodium ion, iron ion, or a solvent.

In order that the present disclosure can be more fully understood, the following examples are set forth. It should be understood that these examples are for illustrative purposes only, and are not to be construed as limiting this disclosure in any manner. For example, the particular materials and amounts thereof recited in these examples, as well as other conditions and details, should not be construed to unduly limit this disclosure.

Examples

All materials are commercially available, for example from Sigma-Aldrich Chemical Company, Milwaukee, WI, USA, or known to those skilled in the art, unless otherwise stated or apparent. The following abbreviations are used in this section: mL = milliliters, g = grams, min = minutes, d = days, nm = nanometers, mm = millimeters, cm = centimeters, wt% = weight percent, rpm = revolutions per minute, and °C = degrees Celsius. Abbreviations for materials used in this section, as well as descriptions of the materials, are provided in Table 1.

Materials

Table 1 : Materials used

Acetone Available from Sigma-Aldrich

Water Distilled water

Carbon Steel Obtained from Propak Systems, Airdrie, Alberta, Canada

Heat Exchanger Titanium alloy heat exchanger plates, available from Alfa Laval, Sweden Plates

SDS Sodium Dodecyl Sulfate, Available from Sigma-Aldrich

Me₂Si(OMe)₂ Available from Sigma-Aldrich

ZrO(N0₃)₂ Zirconium(IV) oxynitrate hydrate, available from Sigma-Aldrich

A1(N0₃) ₃ Aluminum nitrate monohydrate, available from Chem-Impex

International, Wood Dale, IL, USA

Water-free liquid organic -inorganic sol-gel corrosion inhibitor, available

HALOX-550WF

from ICL\Advanced Additives, Hammond, Indiana, USA

Liquid organic corrosion inhibitor, available from ICL\Advanced

HALOX-515LFG

Additives

NEVERWET Moisture repelling barrier product available from Rust-Oleum

Corporation, Vernon Hills, IL, USA

Citrus Cleaner 3M Citrus Based Cleaner, 3M Company, St. Paul, MN, USA

PAA Poly(acrylic acid), 25 wt% solution, with average MW of 240,000 available from Alpha Aesar

Testing Procedures

Procedures for preparing coating preparations

Preparation 1 (P-1): Colloidal nanosilica particles were dispersed into distilled water to obtain a solution containing 5 wt% nanosilica, wherein 85% was composed of NALCO 1060 and 15% composed of NALCO 1115. The resultant dispersion was acidified with H3PO4 to obtain a pH-value of 2-3 and finally, 0.1% of SDS was added to the solution under vigorous stirring to produce a milky, translucent mixture. Preparation 2 (P-2): NALCO 8691 colloidal nanosilica particles were dispersed into distilled water to produce a 5 wt% nanosilica solution. Finally, 0.1% of SDS was added to the solution under vigorous stirring to prepare a colorless coating mixture.

Preparation 3 (P-3): NALCO 1115 colloidal nanosilica particles were dispersed into distilled water to produce a 5 wt% nanosilica solution. Finally, 0.1% of SDS was added to the solution under vigorous stirring to prepare a colorless coating solution. Preparation 4 (P-4): Colloidal nanosilica particles were dispersed into distilled water to obtain a solution containing total of 5 wt% nanosilica, wherein 4.25 wt% of Nalco-1060, 0.35 wt% of Nalco- 1115 and 0.40 wt% of Nalco-8691. The resultant dispersion was acidified with H3PO4 to obtain a pH-value of 2-3 and finally, 0.1% of SDS was added to the solution under vigorous stirring to produce a milky, translucent coating solution.

Preparation 5 (P-5): Colloidal nanosilica particles were dispersed into distilled water to obtain a solution containing total of 5 wt% nanosilica, wherein 4.25 wt% was composed of NALCO 1060 and 0.75 wt% composed of NALCO 8691. The resultant dispersion was acidified with H3PO4 to obtain a pH-value of 2-3, and finally, 0.1% of SDS was added to the solution under vigorous stirring to produce a milky, translucent coating solution.

Preparation 6 (P-6): A 10 wt% solution of Me2Si(OMe)2 and 1 wt% of H2SO4 in isopropanol was prepared as described in Wang et al., Angew. Chem. Int. Ed.; 2016, 55, 244-248.

Preparation 7 (P-7): As described for P-1, but with the addition of ZrO( 03)2 at a concentration of 1%. Preparation 8 (P-8): As described for P-1, but with the addition of A1(N03)3 at a concentration of 2%.

Preparation 9 (P-9): As described for P-1, but with the addition of A1(N03)3 at a concentration of 20%.

Preparation 10 (P-10): As described for P-1, but with the addition of A1( 03)3 at a concentration of 20% and PAA at a concentration of 0.5%.

Preparation 11 (P-11): As described for P-1, but with the addition of PAA at a concentration of 1%.

Preparation 12 (P-12): As described for P-1, but with the addition of HALOX-550WF at a concentration of 2%.

Preparation 13 (P-13): As described for P-1, but with the addition of HALOX-550WF at a concentration of 5%. Preparation 14 (P-14): As described for P-l, but with the addition of HALOX-515LF at a concentration of 5%. Procedure for depositing hydrophilic coatings on heat exchanger plates

Heat exchanger plates composed of titanium alloy were cut into 3.5 x 3.5 cm square sections. Plates were cleaned with toluene, acetone and water prior to application of preparations. Preparations were applied by dipping the plates into preparations, followed by drying in air, three times at ambient temperature. After each experiment, plates were also cleaned with a pad obtained from 3M Company under the trade designation "SCOTCHBRITE 7447" prior to solvent cleaning steps.

Procedure for testing anti-fouling and cleanability of heat exchanger plates

Coated and uncoated sections were arranged in a metal frame to hold the sections parallel with a spacing between the plates of 5 mm. This arrangement replicated the spacing between the heat exchanger plates used in heat exchangers in field operations.

1. The initial weight of plates were recorded after applying the coating (Wi).

2. In each set of experiments, at least one uncoated plate was included to compare the

performance of coated plates against.

3. Approximately 1600 mL of Emulsion B was poured into a metal beaker, for measurements at 80°C and below, or a 1.5 L cylindrical reaction vessel, equipped with silicon oil bath to regulate temperature, obtained from Wilmad-Labglass, Vineland, NJ, USA, for measurements at 90°C.

4. When the metal beaker was used, the metal beaker was placed on a hot plate stirred via mechanical agitation (-450 rpm) and heated to indicated temperature of the experiments.

When the reaction vessel was used, the silicon oil bath was heated to the indicated temperature of the experiment and the emulsion was stirred via mechanical agitation.

5. Upon reaching indicated temperature, the heat exchanger unit containing coated and

uncoated plates was submerged into the emulsion.

6. After indicated experimental time, the unit was removed.

7. Visual inspection of each plate was performed.

8. Each plate was weighed (Wf).

9. Plates were sprayed with low pressure water to determine ease and amount of foulant removal.

10. Optionally, plates were allowed to drain and were weighed again {W ). After plates were taken out of the emulsion, excess emulsion was allowed to drain and the weight of each plate (W) was recorded. The weight gain, Wg [Wg = Wf-Wi, where Wi = Initial weight of the coated or uncoated plate before use for the experiment] and recorded as weight gain from accretion.

After measuring the anti-fouling results, each plate was sprayed with water at a low pressure for approximately one minute to remove the foulant. Afterwards, the plates were dried at ambient temperature, and the weight of each plate was recorded again (Wr). The residual foulant, Wrf that retained on each plate after cleaning was determined from the weight difference [Wrf = Wr-WiJ. Finally, we also calculated the % of cleaning achieved by each coating by using following formula:

% of cleaning = Weight gain from Foulant Accretion fW_f - Residual Foulant (Wrf) ^χ 100

Weight gain from Foulant Accretion (Wg) For some Examples, the coatings were also visually inspected and qualitatively rated based on their ability to prevent accretion of foulant (anti-fouling performance) and their rinse-away cleaning (cleanbility) performance. In the scoring used for the qualitative rating of the performance of the coatings provided in Table 2, a score of 1 represents the best coating performance (low fouling and high cleanability) and 5 represents uncoated performance.

Table 2. Scoring values for qualitative anti-fouling and cleanability performance ratings

Procedure for testing anti-fouling and cleanability of baffle plates

Plates of carbon steel were welded to a circular frame that held plates adjacent to the circumference of and parallel to the axis of a cylindrical, metal container fitted with a mechanical mixer. Testing of anti-fouling and cleanability performance of hydrophilic coatings on carbon steel was carried out by the following procedure: 1. Carbon steel baffle plates were cleaned by rinsing with water and acetone, hydrophilic coating formulations were then applied or not applied to plates as indicated in Table 3.

2. A 20-L metal tank was charged with Emulsion A. The plates were submerged in the emulsion.

3. A mechanical mixer, operated at 300 rpm, was used to mix the emulsion for a period of 15 d.

4. After 15 d, plates were removed from the emulsion and were visually inspected and rated on degree of fouling. Foulant accretion on coated plates was qualitatively compared with uncoated plate according to the rating scale presented above.

5. A stream of water was sprayed at the surface of each plate and the ease of cleaning was qualitatively rated according to the rating scale presented above.

Examples 1 through 6 (EX-1 through EX-6) and Comparative Examples 1 through 6 (CE-1 through CE-6)

For EX-1, three titanium alloy heat exchanger plates were prepared and coated with P-1 according to the procedure described above for hydrophilic coatings on heat exchanger plates. Other plates were cleaned but not coated. Plates were tested for anti-fouling and cleanability according to the procedure above, using Emulsion B. The same procedure was followed for EX-2 through EX-6, and CE-1 through CE-6, with the coating and temperature indicated in Table 3, below. Results presented in Table 3 represent average weight gain and % cleaning results for three replicate experiments with three plates.

Table 3. Anti-fouling and cleanability test results for titanium alloy heat exchanger plates coated with hydrophilic coatings exposed to Emulsion B

Examples 7 and 8 (EX-7 and EX-8) and Counter Example 7 (CE-7)

For EX-7, a carbon steel baffle plate was coated with P-l by the procedure described. For EX-8, a carbon steel baffle plate was coated with P-2 by the procedure described. For CE-7, a carbon steel baffle plate was cleaned but not coated. For EX-7, EX-8, and CE-7, anti-fouling was tested by the procedure for testing anti-fouling and cleanability of baffle plates described above. The results of the testing are presented in Table 4, below.

Table 4. Performance on carbon steel baffles

Example 9 (EX-9) through Example 14 (EX-14) and Counter Examples 8 through 11 (CE-8 through CE-11)

For EX-9 through EX-14, titanium alloy heat exchanger plates were prepared and coated according to the procedure described above for hydrophilic coatings on heat exchanger plates with the coatings as indicated in Table 5, below. For CE-8, a titanium alloy heat exchanger plate was cleaned by rinsing with toluene, acetone, and water before application of the coating indicated in Table 5 according to manufacturer instructions. For CE-10 and CE-11, a titanium alloy heat exchanger plate was cleaned by rinsing with toluene, acetone and water. For CE-9, a titanium alloy heat exchanger plate was cleaned by rinsing with toluene, acetone, and water before application of the coating indicated in Table 5 according to the procedure described above for the indicated coating. Plates were tested for anti-fouling performance according to the procedure described above for heat exchanger plates, with plates exposed to Emulsion B at 60 °C for 6 h. The coating applied, weight gain from foulant accretion, residual foulant after cleaning with water spray, the calculated % cleaning, and qualitative rating are provided in Table 5. The values are averages for two determinations.

Table 5. Anti-fouling performance of hydrophobic and hydrophilic coatings on heat exchanger plates.

Examples 15 through 19 (EX- 15 through EX- 19)

For EX-15 through EX-19, coatings were applied to titanium heat exchanger plates as indicated in Table 6 below according to the procedure described for EX-9, except that, before submersion into emulsion, plates were heated in a ventilated oven at 120 °C for 2 min. Coatings were tested according to the procedure described for EX-9. The applied coating, weight gain from foulant accretion, residual foulant after water spray, and % Cleaning are presented in Table 6. The values are averages for two determinations.

Table 6. Effect of curing of hydrophilic coatings at 120 °C on cleanability.

Examples 20 through 29 (EX-20 through EX-29) and Counter Example 12 (CE-12)

For EX-20 through EX-29, four sections of titanium alloy heat exchanger plate were prepared and coated with P-1 as described for EX-9. All four plates were then repeatedly submerged in Emulsion B for experimental times indicated in Table 7 below. Between submersions, plates were tested for anti-fouling and cleanability as described for EX-9, except that two plates were cleaned using only water and two plates were cleaned using toluene and Citrus Cleaner. For CE-12, uncoated sections of titanium alloy heat exchanger plates were used. One section was tested for each time listed in the table. The results presented for CE-12 are the averages over all uncoated plates tested for CE-12. With the exception of CE-12, the values are averages for two determinations. Table 7. Results of test of foulant accretion and cleaning of coated titanium alloy heat exchanger plates with repeated immersion in emulsion and cleaning with either water or Citrus Cleaner.

Examples 30 through 37 (EX -30 through EX-37) and Counter Examples 13 and 14 (CE-13 and CE- 14)

For EX-30 through EX-37 and CE-13, titanium alloy heat exchanger plates were coated with hydrophilic coating preparations comprising inorganic binders, organic binders, or corrosion inhibitors, as indicated in Table 8. Following coating, coatings were tested for anti-fouling and cleanability as desecribed for EX-4. Performance was tested at the same time for P-1 coated plates and uncoated plates to provide a comparison of performance. The values are averages for two determinations. Table 8. Performance of hydrophilic coatings with inorganic binders or polyacrylic acid.

While the specification has described in detail certain embodiments, it will be appreciated that those skilled in the art, upon attaining an understanding of the foregoing, may readily conceive of alterations to, variations of, and equivalents to these embodiments. Accordingly, it should be understood that this disclosure is not to be unduly limited to the illustrative embodiments set forth hereinabove. Furthermore, all published patent applications and issued patents referenced herein are incorporated by reference in their entirety to the same extent as if each individual publication or patent was specifically and individually indicated to be incorporated by reference. Various exemplary embodiments have been described. These and other embodiments are within the scope of the following listing of claims.

Claims

What is claimed is:

1. A method of making at least a portion of a heat exchanger, the method comprising coating at least the portion of the heat exchanger with a composition comprising hydrophilic nanoparticles and water, wherein the heat exchanger is used for at least one of heating or cooling a fluid comprising a hydrocarbon.

2. The method of claim 1, wherein the composition comprises 1 to 25 percent by weight of the hydrophilic nanoparticles.

3. The method of claim 1 or 2, wherein the composition further comprises surfactant.

4. The method of any one of claims 1 to 3, wherein the composition has a pH from about 1 to about 12.

5. The method of any one of claims 1 to 4, wherein the composition is substantially free of at least one of particles of fluorinated resin or zirconium salts.

6. The method of any one of claims 1 to 5, wherein the composition further comprises at least one of an organic polymeric binder or inorganic binder.

7. A method of at least one of heating or cooling a fluid comprising a hydrocarbon, the method comprising introducing the fluid comprising the hydrocarbon to a heat exchanger, wherein at least a portion of the heat exchanger has a coating comprising hydrophilic nanoparticles.

8. The method of claim 7, further comprising removing foulant adhered to at least the portion of the heat exchanger.

9. The method of claim 8, wherein removing foulant adhered to at least the portion of the heat exchanger comprises rinsing at least the portion of the heat exchanger with at least one of water, organic solvent, or aqueous detergent.

10. The method of any one of claims 7 to 9, wherein the coating is substantially free of at least one of particles of fluorinated resin or zirconium salts.

11. The method of any one of claims 7 to 10, wherein the coating further comprises at least one of an organic polymeric binder or an inorganic binder.

12. The method of any one of claims 1 to 11, wherein any foulant that adheres to at least the portion of the heat exchanger that is coated with the hydrophilic nanoparticles is more easily removed than foulant adhered to a portion of the heat exchanger that is not coated with hydrophilic nanoparticles.

13. A heat exchanger comprising at least a portion that has a coating comprising hydrophilic nanoparticles, wherein the heat exchanger is used for at least one of heating or cooling a fluid comprising a hydrocarbon.

14. The method or heat exchanger of any one of claims 1 to 13, wherein the hydrophilic nanoparticles comprise at least one of silica nanoparticles, alumina nanoparticles, titania nanoparticles, alumina coated silica nanoparticles, or fumed silica nanoparticles.

15. The method or heat exchanger of any one of claims 1 to 14, wherein the hydrophilic nanoparticles have an average diameter of less than about 300 nanometers.