Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F28—HEAT EXCHANGE IN GENERAL
  • F28G—CLEANING OF INTERNAL OR EXTERNAL SURFACES OF HEAT-EXCHANGE OR HEAT-TRANSFER CONDUITS, e.g. WATER TUBES OR BOILERS
  • F28G9/00—Cleaning by flushing or washing, e.g. with chemical solvents
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B08—CLEANING
  • B08B—CLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL
  • B08B3/00—Cleaning by methods involving the use or presence of liquid or steam
  • B08B3/003—Cleaning involving contact with foam
• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
  • C11D11/00—Special methods for preparing compositions containing mixtures of detergents
  • C11D11/04—Special methods for preparing compositions containing mixtures of detergents by chemical means, e.g. by sulfonating in the presence of other compounding ingredients followed by neutralising
• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
  • C11D3/00—Other compounding ingredients of detergent compositions covered in group C11D1/00
  • C11D3/16—Organic compounds
  • C11D3/37—Polymers
  • C11D3/3703—Macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
  • C11D3/3726—Polyurethanes
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23G—CLEANING OR DE-GREASING OF METALLIC MATERIAL BY CHEMICAL METHODS OTHER THAN ELECTROLYSIS
  • C23G5/00—Cleaning or de-greasing metallic material by other methods; Apparatus for cleaning or de-greasing metallic material with organic solvents
  • C23G5/02—Cleaning or de-greasing metallic material by other methods; Apparatus for cleaning or de-greasing metallic material with organic solvents using organic solvents
  • C23G5/032—Cleaning or de-greasing metallic material by other methods; Apparatus for cleaning or de-greasing metallic material with organic solvents using organic solvents containing oxygen-containing compounds
• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
  • C11D2111/00—Cleaning compositions characterised by the objects to be cleaned; Cleaning compositions characterised by non-standard cleaning or washing processes
  • C11D2111/10—Objects to be cleaned
  • C11D2111/14—Hard surfaces
  • C11D2111/20—Industrial or commercial equipment, e.g. reactors, tubes or engines
• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
  • C11D2111/00—Cleaning compositions characterised by the objects to be cleaned; Cleaning compositions characterised by non-standard cleaning or washing processes
  • C11D2111/40—Specific cleaning or washing processes
  • C11D2111/42—Application of foam or a temporary coating on the surface to be cleaned
• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
  • C11D2111/00—Cleaning compositions characterised by the objects to be cleaned; Cleaning compositions characterised by non-standard cleaning or washing processes
  • C11D2111/40—Specific cleaning or washing processes
  • C11D2111/44—Multi-step processes
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F28—HEAT EXCHANGE IN GENERAL
  • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
  • F28D7/00—Heat-exchange apparatus having stationary tubular conduit assemblies for both heat-exchange media, the media being in contact with different sides of a conduit wall
  • F28D7/16—Heat-exchange apparatus having stationary tubular conduit assemblies for both heat-exchange media, the media being in contact with different sides of a conduit wall the conduits being arranged in parallel spaced relation

Definitions

• the invention relates to the field of removing various types of deposits from a surface, preferably the surface of industrial equipment.
• FIG. 1 illustrates the structure of a shell-and-tube heat exchanger.
• the disclosure relates to a method of removing various types of deposits from a surface.
• the deposits can be salt deposits, deposits of a petroleum nature including fouling of heat exchangers, asphaltene-resin-paraffin, and resin and biological (bacterial) deposits.
• the deposit is the fouling in a heat exchanger.
• the deposit is the fouling in a heat exchanger used in oil refinery.
• the surface is the surface of a heat exchanger.
• the surface is the internal surface of shell-and-tube heat exchanger (FIG. 1).
• Heat exchanger fouling is a common problem in heat exchangers. It results in changing the surface of the heat transfer and reducing the efficiency of the heat transfer.
• Corrosion fouling occurs when the fluid corrodes the surface of the exchanger wall, developing a layer of corrosion. This corroded metal prevents efficient heat transfer.
• Particulate fouling occurs when certain suspended particulate matter in the fluid settles down on the heat exchanger wall. Over time a layer of such particulate material develops on the wall, reducing the heat transfer through it.
• Precipitation fouling occurs when the circulating fluid precipitates as time goes by, then the precipitates deposit on the surface of the exchanger wall, forming precipitation fouling.
• Polymerization fouling [0016] Sometimes the fluid can undergo a reaction at the heat exchanger wall surface. This reaction produces a solid that adheres to the heat exchanger wall, resulting in polymerization fouling.
• Organisms present in the fluid stream can get attracted to the warm surface of the heat exchanger wall. Here they can grow in size and reproduce, forming a layer of biological material, called bio fouling.
• the fluid temperature near the heat exchanger walls can drop so low that some of the fluid freezes. This frozen solid remains on the heat exchanger wall. But it is not as conductive as the exchanger wall and it restricts the heat transfer across the wall, resulting in freezing fouling.
• This disclosure relates to a method of for removing deposits from a surface comprising the steps of applying a first precursor mix to the surface; allowing the first precursor mix to pass through the deposits; removing the first precursor mix; applying a second precursor mix to the surface; allowing the second precursor mix to pass though the deposits; removing the second precursor mix; wherein the first precursor mix reacts with the second precursor mix to produce a foam, and the foam expands inside pores and cracks of the deposits, and results in breaking the deposit from the surface.
• the deposits can be salt deposits, deposits of a petroleum nature including fouling of heat exchangers, asphaltene-resin-paraffin, and resin and biological (bacterial) deposits.
• the deposit is the fouling in a heat exchanger.
• the deposit is the fouling in a heat exchanger.
• the deposit is the fouling of a heat exchanger used in oil refinery.
• the fouling is selected from the group consisting of corrosion fouling, particulate fouling, precipitation fouling polymerization fouling, bio fouling, freezing fouling, and mixtures thereof.
• the method described herein is used to clean the heat exchangers used in oil refinery.
• the heat exchanger is a shell-and-tube heat exchanger.
• the advantage of the cleaning method described herein is that it does not require to disassemble the heat exchanger; it can be performed in a short period of time; it takes advantage of the high internal pressure in the process of foam formation to break the deposits from the surface (e. g. the heat exchanger wall).
• the foam is a polymer foam selected from the group consisting of polyethylenes, polyurethanes, polyesters, and acrylonitrile-butadienc-styrene.
• the foam is a polyurethane foam, also called urethane foam.
• Polyurethane foams are widely used in a variety of applications, including the packaging industry, in which polyurethane foams are used for cushioning fragile articles for shipping and handling.
• Various processes for producing polyurethane foams are known in the art.
• a polyol-containing precursor and an isocyanate-containing precursor are brought together and mixed in the presence of a catalyst to cause a reaction which leads to curing and solidification of the mixture.
• a blowing agent is introduced into the mixture so that foaming of the mixture occurs.
• the polyurethane foaming composition comprises a first precursor mix and a second precursor mix.
• polyurethane is formed by a polyol reacting with a poly isocyanate. Therefore, the polyol or the poly isocyanate can be present in either the first precursor mix or the second precursor mix, but not both.
• Other additives e.g. a catalyst, a blowing agent, a surfactant, a chain extender, a crosslinker, a flame retardant, and an antioxidant, can be in either the first precursor mix or the second precursor mix or both.
• the first precursor mix comprises a polyol; the second precursor mix comprises a polyisocyanate. In one embodiment, the first precursor mix comprises a polyisocyanate; the second precursor mix comprises a polyol. In one embodiment, the first precursor mix comprises a polyol, a catalyst, a blowing agent, and a surfactant.
• the first precursor mix optionally comprises a chain extender, a crosslinker, a flame retardant, and/or an antioxidant.
• the second precursor mix comprises a polyol, a catalyst, a blowing agent, and a surfactant.
• the second precursor mix optionally comprises a chain extender, a crosslinker, a flame retardant, and/or an antioxidant.
• the polyol is a polyester made from an acid selected from the group consisting of succinic acid, glutanic acid, adipic acid, suberic acid, azelaic acid, sebacic acid, phthalic acid, iso-phthalic acid, dodecanedicarboxylic acid, and mixtures thereof.
• the polyol is a glycol selected from the group consisting of ethylene glycol, 1 ,2- propylene glycol, 1,3-propylene glycol, 1,3-butylene glycol, tetramethylene glycol, diethylene glycol, methylene glycol, pentamethylene glycol, hexamethylene glycol, xylylene glycol, and mixtures thereof.
• the polyol is a polyether selected from the group consisting of poly(oxypropylene)glycols, poly(oxypropylene)-poly(oxyethylene)copolymer glycols, poly(oxybutylene)glycols, poly(oxyethylene)glycols, poly(oxytetramethylene)glycols, poly(oxypropylene)glycerols, poly(oxypropylene)trimethylolpropanes, poly(oxypropylene)- 1,2,6-hexanetriols, poly(ethyleneoxide propyleneoxide ethylenediamine)polyethers, poly(oxyalkylene)sorbitols, poly(oxyalkylene) pentaerythritols, poly(oxyalkylene)sucrose, poly(oxyalkylene)glucose, and mixtures thereof.
• poly(oxypropylene)glycols poly(oxypropylene)-poly(oxyethylene)copolymer glycols, poly(oxybuty
• the weight average molecular weight of the polyol is between 1000 to 3000.
• the polydispersity index of the polyol is between 0.5 to 1.
• the polyol is present in the first precursor mix at a weight percentage range 70-95% of the total weight of the first precursor mix.
• the blowing agent is HFC-245fa (1,1,1,3,3-pentafluoropropane) and HFC-134a (1,1,1,2-tetrafluoroethane), or hydrocarbons such as n-pentane.
• the blowing agent is selected from the group consisting of: hexafluoropropene, 2-fluoropropene,
• the blowing agent is present in the first precursor mix at a weight percentage range 0.5-5% of the total weight of the first precursor mix. In some embodiments, the blowing agent is present in the first precursor mix at a weight percentage of the total weight of the first precursor mix selected from the group consisting of about 0.5 wt. %, about 1 wt. %, about 2 wt. %, about 3 wt. %, about 4 wt. %, and about 5 wt. %.
• the first precursor mix further comprises a catalyst.
• the catalyst is selected from the group consisting of alkyl tin carboxylates, triethylenediamine, l,4-diazabicyclo[2.2.2]octane, dimethylcyclohexylamine (DMCHA), dimethylethanolamine (DMEA), bis-(2-dimethylaminoethyl)ether, dibutyltin dilaurate, and mixtures thereof.
• the catalyst is present in the first precursor mix at a weight percentage range 0.1 -0.9% of the total weight of the first precursor mix.
• the catalyst is present in the first precursor mix at a weight percentage of the total weight of the first precursor mix selected from the group consisting of about 0.01 wt. %, about 0.05 wt. %, about 0.1 wt. %, about 0.15 wt. %, about 0.2 wt. %, about 0.25 wt. %, about 0.3 wt. %, about 0.35 wt. %, about 0.4 wt. %, about 0.45 wt. %, about 0.5 wt. %, about 0.5 wt. %, about 0.6 wt. %, about 0.7 wt. %, about 0.8 wt. %, about 0.9 wt. %, and about 1 wt. %.
• the first precursor mix further comprises a surfactant.
• the surfactant is selected from the group consisting of dialkyl sulfosuccinic acid metal salts, dialkyl sulfosuccinic acid organic salts, alkyl benzenesulfonic acid metal salts, alkyl benzenesulfonic acid organic salts, Silwet-L-5130, and mixtures thereof.
• the surfactant is present in the first precursor mix at a weight percentage range 1 -9% of the total weight of the first precursor mix.
• the surfactant is present in the first precursor mix at a weight percentage range of the total weight of the first precursor mix selected from the group consisting of about 1 wt. %, about 2 wt. %, about 3 wt. %, about 4 wt. %, about 5 wt. %, about 6 wt. %, about 7 wt. %, about 8 wt. %, about 9 wt. %, and about 10 wt. %.
• the first precursor mix optionally comprises a chain extender.
• the chain extender is selected from the group consisting of ethylene glycol, 1,3- propanediol, 1,2-propanediol, 1 ,4-butanediol (BDO), 1,5-pentanediol, 1,6-hexanediol, 1,7- heptanediol, 1,8-octanediol, 1,9-nonanediol, 1 ,10-decanediol, 1,11 -undecanediol, 1,12- dodecanediol, 1 ,2-cyclohexanedimethanol, 1 ,4-cyclohexanedimethanol, the corresponding diamine and dithiol analogs thereof, lysine ethyl ester, arginine ethyl ester, and p-alanine-based
• the chain extender is present in the first precursor mix at a weight percentage range 1 -9% of the total weight of the first precursor mix. In some embodiments, the chain extender is present in the first precursor mix at a weight percentage of the total weight of the first precursor mix selected from the group consisting of about 1 wt. %, about 2 wt. %, about 3 wt. %, about 4 wt. %, about 5 wt. %, about 6 wt. %, about 7 wt. %, about 8 wt. %, about 9 wt. %, and about 10 wt. %.
• the first precursor mix optionally comprises a crosslinker.
• the crosslinker is selected from the group consisting of siloxane and alkyl polysilicate.
• the crosslinker is present in the first precursor mix at a weight percentage range 1-9% of the total weight of the first precursor mix.
• the crosslinker is present in the first precursor mix at a weight percentage range of the total weight of the first precursor mix selected from the group consisting of about 1 wt. %, about 2 wt. %, about 3 wt. %, about 4 wt. %, about 5 wt. %, about 6 wt. %, about 7 wt. %, about 8 wt. %, about 9 wt. %, and about 10 wt. %.
• the polyurethane foam comprises a second precursor mix comprising a polyisocyanate.
• the polyisocyanate is selected from the group consisting of ethylene diisocyanate, 1 ,4-tetramethylene diisocyanate, 1 ,6-hexamethylene diisocyanate, 1,12- dodecanediisocyanate, cyclobutane- 1,3 -diisocyanate, cyclohexane- 1, 3- and -1,4-diisocyanate, 1- isocyanato-3,3,5-trimethyl-5-isocyanatomethyl-cyclohexane (isophorondiisocyanate), 2,4- and
• 2,6-hexahydrotoluene diisocyanate dicyclohexylmethane-4,4'-diisocyanate (hydrogenated MDI or HMDI), 1,3- and 1 ,4-phenylenediisocyanate, 2,4- and 2,6-toluene diisocyanate (TDI), diphenylmethane-2,4'- and / or -4,4'-diisocyanate ( MDI), naphthylene-l,5-diiso ianate, triphenylmethane-4,4 ', 4"- triisocyanate, polyphenyl-polymethylene-polyisocyanates (MDI raw materials), norbornanedi isocyanates, m- and p-isocyanatophenylsulfonylisocyanates, perchlorinated arylpolyisocyanates, modified polyisocyanates, carbodiimide-modified polyis
• the polyisocyanate is present in the second precursor mix at a weight percentage range 70-90% of the total weight of the second precursor mix.
• the method disclosed herein further comprises the step of removing the debris and the foam using a solvent.
• the solvent is selected from the group consisting of dimethylformamide, dimethylacetamide, N-methylpyrrolidone, dichloromethane, perchloroethylene, chlorobenzene, dioxane, cyclohexanone or mixtures thereof.
• the method disclosed herein may further comprise the step of the cleaning the surface using a composition comprising hydrogen peroxide, catalyst for decomposing peroxide compounds, SAA, chelating agent, water-soluble calixarene, anti-foaming agent and water.
• a composition comprising hydrogen peroxide, catalyst for decomposing peroxide compounds, SAA, chelating agent, water-soluble calixarene, anti-foaming agent and water.
• the precursor mix described herein can be prepared in-place. Once it is prepared, several chemical and physical processes start simultaneously, such as polymerization reactions and foaming process during which gas bubbles are formed. The gas bubbles lead the expansion of the foaming inside the pores or cracks of the deposits, and eventually break the deposits away from the surface. Therefore, the components and concentrations thereof in the precursor mix must be chosen in such a way as foaming processes results in breaking the deposits away from the surface.
• the selection criterion for precursor mix formulation is the median size of bubbles which should be smaller than the median diameter of pores in the fouling deposits.
• the fouled equipment is soaked in the precursor mix or it is kept in contact with the precursor mix.
• the precursor mix is allowed to be in contact with the fouled equipment in a period of time sufficient for the precursor mix to penetrate the cracks or pores inside the deposits.
• the sufficient time is selected from the group consisting of 10 minutes, 20 minutes, 30 minutes, 40 minutes, 50 minutes, 60 minutes, 70 minutes, 80 minutes, 90 minutes, and 100 minutes.
• Example 1 Removing deposits in a heat exchanger
• the following prophetic example illustrates the applying of method for clean-up of a shell side of a small-size shell-and-tube heat-exchanger fouled with porous petcoke deposits.
• the fouling consists mostly of elemental carbon, the average thickness of fouling layer is 5 mm.
• the median pore diameter is 0.02 mm.
• the first precursor mix (hereinafter referred to as component A) comprises the following ingredients:
• Polyether polyol (M.W. 1000-3000) - 95 pbw
• the second precursor mix (hereinafter referred to as component B) is technical grade toluene diisocyanate.
• the shell side of the heat-exchanger (hereinafter referred to as contour) is filled with Component A and left undisturbed for 30 min.
• Component A is drained from the contour in recycle storage tank.
• the contour is filled with component B and left undisturbed for 2 min.
• Component B is drained from the contour in recycle storage tank.
• the circulation loop is filled with dimethylformamide. Dimethylformamide is circulated for 1 hour and than drained into recycle storage tank. Whole process is carried out at 25°C. The inspection of dismantled tube bundle showed complete removal of all fouling material.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Organic Chemistry (AREA)
• Mechanical Engineering (AREA)
• Life Sciences & Earth Sciences (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Wood Science & Technology (AREA)
• General Engineering & Computer Science (AREA)
• General Chemical & Material Sciences (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Combustion & Propulsion (AREA)
• Polyurethanes Or Polyureas (AREA)

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• 2020
  • 2020-07-13 WO PCT/RU2020/000346 patent/WO2022015187A1/en not_active Ceased
  • 2020-07-13 EP EP20945151.7A patent/EP4179130B1/de active Active

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