WO2023228525A1 - Procédé d'amélioration d'efficacité de transfert de chaleur d'échangeur de chaleur - Google Patents

Procédé d'amélioration d'efficacité de transfert de chaleur d'échangeur de chaleur Download PDF

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WO2023228525A1
WO2023228525A1 PCT/JP2023/009849 JP2023009849W WO2023228525A1 WO 2023228525 A1 WO2023228525 A1 WO 2023228525A1 JP 2023009849 W JP2023009849 W JP 2023009849W WO 2023228525 A1 WO2023228525 A1 WO 2023228525A1
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heat exchanger
water
acid
forming
repellent film
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PCT/JP2023/009849
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English (en)
Japanese (ja)
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一也 渡邊
雅一 小泉
忠芳 吉川
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栗田工業株式会社
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    • 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
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C26/00—Coating not provided for in groups C23C2/00 - C23C24/00
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F13/00—Arrangements for modifying heat-transfer, e.g. increasing, decreasing
    • F28F13/18—Arrangements for modifying heat-transfer, e.g. increasing, decreasing by applying coatings, e.g. radiation-absorbing, radiation-reflecting; by surface treatment, e.g. polishing

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  • the present invention relates to a method for improving the heat transfer efficiency of a heat exchanger that heats an object to be heated or condenses steam.
  • the steam comes into contact with the heat exchanger heat transfer surface whose temperature is lower than the saturated state, and the steam liquefies and condenses.
  • liquefaction condensation of vapor There are two types of liquefaction condensation of vapor: film condensation, in which the condensed liquid forms a continuous liquid film on a wall surface, and droplet condensation, in which the condensed liquid forms many droplets on the wall surface. Since the heat transfer rate of droplet condensation is several to several tens of times higher than that of film condensation, various studies have been made on droplet condensation methods for steam.
  • Patent Document 1 describes a method for improving heat transfer efficiency using steam using a long-chain aliphatic amine.
  • Patent Document 2 describes a method for improving heat transfer efficiency using a droplet-like condensation accelerator made of a volatile amine compound as a method for condensing steam.
  • An object of the present invention is to provide a method for improving heat transfer efficiency of a heat exchanger that can quickly improve the heat transfer efficiency of a heat exchanger.
  • the present inventors have found that the surface of a heat exchanger is brought into contact with an acid and a water-repellent film-forming substance at the same time (if the water-repellent film-forming substance is an acid, the acid alone). Then, the water-repellent film-forming substance becomes more easily adsorbed on the heat exchanger surface, and a water-repellent film is efficiently formed on the heat exchanger surface, and the effect of promoting droplet condensation of steam appears at an early stage, resulting in an early increase in heat transfer efficiency. It was found that this can be improved.
  • the present invention is based on this knowledge and has the following gist.
  • a method for improving heat transfer efficiency of a heat exchanger comprising forming a water-repellent film by contacting the heat exchanger with a liquid containing an acid and a water-repellent film-forming substance.
  • a method for improving heat transfer efficiency of a heat exchanger comprising forming a water-repellent film by contacting the heat exchanger with a liquid containing an acidic water-repellent film-forming substance.
  • the surface of the heat exchanger (the surface in contact with steam) is brought into contact with an acid and a water-repellent film-forming substance at the same time (if the water-repellent film-forming substance is an acid, the water-repellent film-forming substance alone) to quickly repel the water-repellent film.
  • a water film forms on the heat exchanger surface. This promotes droplet condensation in the heat exchanger and improves heat transfer efficiency at an early stage.
  • the heat transfer efficiency of various heat exchangers such as a vulcanization device, a drying device, and a temperature raising device can be improved at an early stage.
  • a condensed water film film-like condensation
  • the heating efficiency by the steam can be effectively improved.
  • FIG. 2 is a configuration diagram of a heat exchange test device used in Examples.
  • the water-repellent film-forming substance may be simply referred to as a film-forming substance.
  • the heat exchanger surface (metal surface) is brought into contact with an acid and a water-repellent film-forming substance at the same time (if the water-repellent film-forming substance is an acid, the water-repellent film-forming substance alone). Forms a water-repellent film on the surface. If only an acid that does not have the action of forming a water-repellent film is brought into contact with the surface of the heat exchanger, water repellency cannot be imparted to the metal surface of the heat exchanger.
  • the metal cannot be eluted from the metal surface of the heat exchanger, making it impossible to form a water-repellent film at an early stage.
  • the acid dissolves the metal from the metal surface (creating an anodic environment). ), the film-forming substance can be adsorbed onto the heat exchanger surface at an early stage.
  • acid has the effect of removing rust that has adhered to the surface of the heat exchanger. If a large amount of rust adheres to the heat exchanger surface, the acid and film-forming substance are consumed by the rust, and a sufficient water-repellent film effect may not be obtained. Therefore, if there is a lot of rust on the surface of the heat exchanger, use an acid to remove the rust on the surface of the heat exchanger, and then apply the acid and film-forming substance at the same time (if the water-repellent film-forming substance is an acid, (water film-forming substance alone) may be contacted.
  • the acid and the water-repellent film-forming substance In order to bring the acid and the water-repellent film-forming substance into contact with the heat exchanger surface (metal surface) at the same time (if the water-repellent film-forming substance is an acid, the water-repellent film-forming substance alone), the acid and the water-repellent film-forming substance (When the water-repellent film-forming substance is an acid, it is preferable to bring the heat exchanger surface into contact with a liquid containing a water-repellent film-forming substance (hereinafter sometimes referred to as a water-repellent film-forming treatment liquid).
  • a water-repellent film-forming treatment liquid a liquid containing a water-repellent film-forming substance
  • the acid used in the water-repellent film forming treatment solution is an inorganic acid and/or an organic acid.
  • hydrochloric acid is particularly preferred, but any other inorganic acid can be used without limitation as long as it can elute the metal of the heat exchanger.
  • concentration of hydrochloric acid in the water-repellent film forming treatment solution is preferably 0.01 to 10% (wt%; hereinafter the same), particularly 0.1 to 5%. If the concentration of hydrochloric acid is lower than this range, the metal elution reaction by hydrochloric acid will not occur sufficiently, and if it is too high, the metal may be corroded too much.
  • the organic acids used in the water-repellent film forming treatment solution are preferably one or more hydroxy acids.
  • Particularly preferred hydroxy acids are citric acid and glycolic acid, but any other hydroxy acids can be used as long as they can elute the metal from the heat exchanger.
  • citric acid and glycolic acid it is preferable to use two types of the above-mentioned citric acid and glycolic acid in combination, either one type may be used. If only citric acid is used, iron salt of citric acid may be precipitated, and if only glycolic acid is used, the ability of glycolic acid to form a complex with iron in the alkaline range is low.
  • the organic acid concentration in the water-repellent film forming treatment solution is preferably 0.001 to 50% (wt%; hereinafter the same), particularly 0.01 to 20%.
  • the film-forming substance used in the present invention is preferably a film-forming amine and/or a sarcosine compound.
  • film-forming amines include long chain saturated monoamines such as dodecylamine, tridecylamine, tetradecylamine, pentadecylamine, hexadecylamine, heptadecylamine, octadecylamine, nonadecylamine, eicosylamine, and docosylamine.
  • aliphatic amines include aliphatic amines, long-chain unsaturated aliphatic amines such as oleylamine, ricinoleylamine, linoleylamine, linolenylamine, mixed amines such as coconut oil amine, hydrogenated tallow amine, and mixtures thereof.
  • polyamines represented by the following general formula (1) are also preferred.
  • R 1 represents a saturated or unsaturated hydrocarbon group having 10 to 22 carbon atoms
  • m is an integer of 1 to 8
  • n is an integer of 1 to 7.
  • the plurality of NH-(CH 2 ) m may be the same or different.
  • the saturated or unsaturated hydrocarbon group for R1 may be linear, branched, or cyclic, and may include an alkyl group, an alkenyl group, an alkadienyl group, an alkynyl group, etc. However, preferred are a straight-chain alkyl group and a straight-chain alkenyl group, and the number of carbon atoms in R 1 is preferably 15 to 22.
  • n is an integer of 1 to 8, preferably an integer of 2 to 6 from the viewpoint of corrosion inhibition.
  • Examples of the (CH 2 ) m group include a methylene group, an ethylene group (dimethylene group), a propylene group (trimethylene group), and a butylene group (tetramethylene group), and preferably a propylene group.
  • n is preferably an integer of 1 to 3 from the viewpoint of corrosion inhibition.
  • polyamines include dodecylaminomethyleneamine, dodecylaminodimethyleneamine, dodecylaminotrimethyleneamine (N-stearyl-1,3-propanediamine), and corresponding polyamines such as tetradecyl, hexadecyl, and Examples include octadecyl compound, octadecenylaminotrimethyleneamine, octadecenylaminodi-(trimethylamino)-trimethyleneamine, palmitylaminotrimethyleneamine, tallow alkyldiamine ethoxylate, etc.
  • N-oleyl-1,3-propanediamine also known as N-octadecenylpropane-3-diamine, oleylpropylenediamine.
  • Akzo's product name "Ethiduomine” (a 7:3 mixture of Tris(2-hydroxyethyl)-N-tallowalkyl1,3-diaminopropane and di(2-hydroxyethyl)-N-tallowalkyl amine) can also be suitably used. .
  • the saturated or unsaturated hydrocarbon group for R2 may be linear, branched, or cyclic, and may include an alkyl group, an alkenyl group, an alkadienyl group, an alkynyl group, etc. However, preferred are a straight-chain alkyl group and a straight-chain alkenyl group, and the number of carbon atoms in R 2 is preferably 15 to 22.
  • n 0, 1 or 2, preferably 1 or 2 from the viewpoint of corrosion inhibition.
  • R 3 is a salt-forming group other than H
  • preferred examples of the salt-forming group include an amino group, an ammonium ion, and an alkali metal ion.
  • sarcosine compounds particularly preferred are oleoyl sarcosine, lauroyl sarcosine, stearoyl sarcosine, and cocoyl sarcosine, which can be used alone or in combination of two or more types if necessary.
  • sarcosine compounds may be used by being dissolved in a solvent such as methanol, ethanol, isopropanol, etc., but it is preferable to use an aqueous emulsion by adding a neutralizing amine or using an emulsifier.
  • a neutralizing amine or using an emulsifier.
  • the emulsifier one having a high HLB (hydrophilic-lipophilic balance) value is preferable. This value is preferably 12 to 16, more preferably 13 to 15.
  • the sarcosine compound When R 3 of the sarcosine compound is H, the sarcosine compound has acidity due to the carboxy group and can elute the metal of the heat exchanger, so it may be used alone. However, in order to increase the amount of metal eluted from the heat exchanger surface, it may be used in combination with other organic acids or inorganic acids. Even if the film-forming substance is not a sarcosine compound, any acid that can elute the metal can be used.
  • the above-mentioned film-forming amine and sarcosine compound may be used alone or in combination of two or more.
  • the concentration of the film-forming substance in the water-repellent film-forming treatment liquid is preferably 0.001 to 50%, more preferably 0.01 to 30%, particularly preferably 0.1 to 20%. If the concentration of the film-forming substance is lower than this range, the effect of suppressing condensed water film formation and the effect of improving heating efficiency cannot be sufficiently obtained, and if the concentration of the film-forming substance is too high, sticky deposits will occur in the system. There is a risk.
  • the water-repellent film forming treatment liquid may further contain other chemicals.
  • it may contain a neutralizing amine that has a pH adjusting function.
  • a neutralizing amine allows the sarcosine compound to be stably dissolved in the liquid, resulting in the effect of reducing the corrosion rate of the steam drum and the steam condensate piping before and after the drum.
  • neutralizing amines examples include ammonia, monoethanolamine (MEA), cyclohexylamine (CHA), morpholine (MOR), diethylethanolamine (DEEA), monoisopropanolamine (MIPA), 3-methoxypropylamine (MOPA), Volatile amines such as 2-amino-2-methyl-1-propanol (AMP) and diglycolamine (DGA) can be used. These may be used alone or in combination of two or more. Further, instead of the neutralizing amine, the pH may be adjusted using ammonia derived from the thermal decomposition of the oxygen scavenger described below.
  • the concentration of the neutralizing amine in the water-repellent film-forming treatment solution varies depending on the amount of film-forming amine and sarcosine compound used, the type of object to be heated, the type of equipment, etc. It is preferably .001 to 50%, particularly 0.1 to 20%.
  • the water-repellent film forming treatment liquid may contain an oxygen scavenger.
  • an oxygen scavenger When used in combination with an oxygen scavenger, it is possible to achieve the same effect as with neutralizing amines in reducing corrosion of steam drums, etc.
  • hydrazine derivatives such as hydrazine and carbohydrazide can be used.
  • non-hydrazine oxygen scavengers carbohydrazide, hydroquinone, 1-aminopyrrolidine, 1-amino-4-methylpiperazine, N,N-diethylhydroxylamine, isopropylhydroxylamine, erythorbic acid or its salt, ascorbic acid or Salts thereof, tannic acid or salts thereof, sugars, sodium sulfite, etc. can also be used. These may be used alone or in combination of two or more.
  • the emulsifier examples include polyoxyethylene alkylamine, and preferably polyoxyethylene alkylamine whose alkyl group has 10 to 18 carbon atoms.
  • fatty acid alkali metal salts particularly saturated or unsaturated fatty acid alkali metal salts having 8 to 24 carbon atoms, particularly 10 to 22 carbon atoms, can be suitably used.
  • capric acid examples include sodium salts and potassium salts of saturated or unsaturated fatty acids such as lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, oleic acid, erucic acid, linoleic acid, and linolenic acid.
  • fatty acid alkali metal salt sodium salts and potassium salts of fatty acids produced from edible fats and oils can also be preferably used.
  • fatty acid alkali metal salt in particular, an alkali metal salt of a fatty acid containing 25% by weight or more of at least one selected from unsaturated fatty acids having 14 to 22 carbon atoms, such as oleic acid, erucic acid, linoleic acid, and linolenic acid. suitable.
  • unsaturated fatty acids having 14 to 22 carbon atoms such as oleic acid, erucic acid, linoleic acid, and linolenic acid.
  • the emulsifier esters of glycerin and the aforementioned fatty acids can also be suitably used, and esters of stearic acid can be particularly preferably used. These emulsifiers may be used alone or in combination of two or more.
  • the blending ratio of polyamine and emulsifier should be 40/1 to 1/1 in weight ratio (polyamine/emulsifier), especially about 20/1 to 2/1. suitable.
  • a reducing agent may be used in combination with the above-mentioned film-forming substance or film-forming substance and acid.
  • a reducing agent is used in combination, it is possible to prevent oxidizing ions such as Fe 3+ eluted by the acid from corroding the metal.
  • erythorbic acid erythorbic acid, hydrazine, etc.
  • the reducing agent is not erythorbic acid or hydrazine, it can be used without any restriction as long as it can reduce oxidizing ions such as Fe 3+ .
  • the above reducing agents may be used alone or in combination of two or more.
  • the concentration of the reducing agent in the water-repellent film forming treatment solution varies depending on the amount of acid, film-forming amine or sarcosine compound used, the type of object to be heated, the type of equipment, etc., but the concentration is 0.001. It is preferable to set it to 50%, particularly 0.1 to 20%.
  • an anticorrosive agent may be used in combination with the above-mentioned film-forming substance and acid, and corrosion of metal can be prevented by using the anticorrosive agent in combination.
  • the anticorrosive agent the above-mentioned film-forming amines, sarcosine compounds, EDTA, Asahi Chemical's Ibit series (2S, 30AR, 30D, 2AS, 500A, 155K, 9HS, 3HS, etc.), etc. can be used.
  • the above anticorrosive agents may be used alone or in combination of two or more.
  • the concentration of the anticorrosive agent in the water-repellent film forming treatment solution varies depending on the amount of acid, film-forming amine or sarcosine compound used, the type of object to be heated, the type of equipment, etc., but the concentration is 0.0001. It is preferably 10% to 10%, particularly 0.001 to 1%. If the amount of anticorrosion agent is too small than this range, sufficient anticorrosion effect cannot be obtained, and if it is too large, it becomes difficult for the film-forming substance to adsorb to the metal surface, so the effect of suppressing condensed water film formation and improving heating efficiency is reduced. Can't get enough.
  • the water-repellent film-forming treatment liquid In order to bring the water-repellent film-forming treatment liquid into contact with the surface of the heat exchanger, it is preferable to flow the water-repellent film-forming treatment liquid along the surface of the heat exchanger.
  • the flow rate of the water-repellent film forming treatment solution varies depending on the concentration of the acid, film-forming amine and sarcosine compound, the type and type of heat exchanger, etc., but the flow rate along the heat exchanger surface is 0.01 to 10 m/min, In particular, it is preferable to set the speed to 0.1 to 1.0 m/min. If the flow rate is slower than this range, the acid and film-forming substance will not be uniformly supplied to the heat exchanger surface, which may result in an uneven water-repellent film. ) On the other hand, if the flow rate is too fast, the metal will be eluted too quickly and there is a risk that the heat exchanger will corrode.
  • the temperature of the water-repellent film-forming treatment solution varies depending on the acid, the amount of film-forming amine or sarcosine compound used, the type and type of heat exchanger, etc., but is preferably 10 to 80°C, particularly 25 to 70°C. If the temperature is lower than this range, the rate of formation of the water-repellent film will be slow, and if the temperature is too high, there is a risk that the water-repellent film-forming treatment liquid will evaporate.
  • the surface is washed with water without exposing it to air (the acid and the film-forming substance or the acidic film-forming substance are removed). It is preferable. If acid and film-forming substances or acidic film-forming substances are exposed to air without being removed, the heat exchanger surface may corrode.
  • heat exchangers to which the present invention is applied include, for example, steam turbines, low-pressure turbines, etc. (steam turbines after intermediate-pressure turbines), condensers, air-cooled Examples include a type condenser, a drying device, a concentration device, a temperature raising device, etc.
  • the material of the heat exchanger to which the present invention is applied for example, mild steel, low alloy steel, alloy steel, copper, copper alloy (brass, cupronickel, etc.), titanium, titanium alloy, aluminum, aluminum alloy Examples include.
  • film-forming amines have conventionally been added to boiler feed water as anticorrosive agents, but some of the film-forming amines added to boiler feed water are contained in boiler blow water. It is discharged outside the system and does not reach the heat exchanger in the latter stage of the boiler, making little contribution to promoting droplet condensation within the heat exchanger. Furthermore, the film-forming amine contained in the steam from the boiler and discharged from the boiler is also consumed in the piping and equipment up to the heat exchanger. In addition, if high-temperature equipment such as a superheater or high-pressure equipment is installed between the boiler and the heat exchanger, the film-forming amine in the steam will decompose in these equipment, resulting in heat loss. The amount of film-forming amine that can form a water-repellent film on the surface of the heat exchanger cannot reach the heat exchanger. Alternatively, it takes a long time to form a water-repellent film within the heat exchanger.
  • the added droplet-form condensation accelerator can be directly added to the steam introduced into the heat exchanger or the heat exchanger. It can function effectively in forming a water-repellent film on the surface of the cooling body, and a droplet condensation promoting effect commensurate with the amount added can be stably and quickly obtained.
  • the droplet-like condensation promoter in order to add the droplet-like condensation promoter to the steam introduced into the heat exchanger, it is preferable to provide a pouring point for the droplet-like condensation promoter on the inlet side of the heat exchanger. Specifically, it is preferable to add the droplet condensation accelerator at a chemical injection point where there is no equipment that increases temperature and/or pressure between the chemical injection point and the heat exchanger.
  • the condenser When make-up water is supplied to the make-up water, a method of adding a droplet-like condensation promoter to the make-up water and adding the make-up water containing the droplet-like condensation promoter to a condenser that is a heat exchanger can be mentioned.
  • the temperature at which the droplet-shaped condensation accelerator is easily thermally decomposed for example, 350°C or higher, is present in the system from the injection point of the droplet-shaped condensation accelerator to the heat exchanger.
  • the temperature at which the droplet-shaped condensation accelerator is easily thermally decomposed for example, 350°C or higher, is present in the system from the injection point of the droplet-shaped condensation accelerator to the heat exchanger.
  • the droplet-like condensation accelerator used in the present invention may be any one that is volatile, has a surfactant effect, and has the effect of promoting droplet-like condensation, and includes volatile amine compounds conventionally used as anticorrosive agents. (film-forming amines) and volatile non-amine compounds.
  • volatile amine compounds include the aforementioned film-forming amines. That is, specific examples of film-forming amines include monoamines such as dodecylamine, tridecylamine, tetradecylamine, pentadecylamine, hexadecylamine, heptadecylamine, octadecylamine, nonadecylamine, eicosylamine, and docosylamine.
  • monoamines such as dodecylamine, tridecylamine, tetradecylamine, pentadecylamine, hexadecylamine, heptadecylamine, octadecylamine, nonadecylamine, eicosylamine, and docosylamine.
  • Examples include chain saturated aliphatic amines, long chain unsaturated aliphatic amines such as oleylamine, ricinoleylamine, linoleylamine, linolenylamine, mixed amines such as coconut oil amine, hydrogenated tallow amine, and mixtures thereof.
  • polyamines represented by the above general formula (1) are also preferred.
  • volatile non-amine compounds examples include polyethylene (20) sorbitan monostearate, sorbitan monostearate, sorbitan monolaurate, and the like.
  • droplet-like condensation accelerators may be used alone or in combination of two or more.
  • the amount of the droplet condensation accelerator to be added is sufficient as long as the effect of promoting droplet condensation in the heat exchanger is obtained, and it varies depending on the type of the droplet condensation accelerator and the type of heat exchanger. It is preferably about 0.001 to 10 mg/L, particularly about 0.01 to 2.0 mg/L, based on the converted steam amount.
  • the droplet-like condensation accelerator may be added intermittently or continuously, but from the viewpoint of stably maintaining a water-repellent film due to condensation on the surface of the cooling body in the heat exchanger, continuous addition is preferable.
  • the droplet-like condensation accelerator may be dissolved in a solvent such as methanol, ethanol, isopropanol, etc. in addition to water and added to the steam or heat exchanger. You can also add it to the container.
  • a solvent such as methanol, ethanol, isopropanol, etc.
  • the emulsifier one having a high HLB (hydrophilic-lipophilic balance) value is preferable. This value is preferably 12 to 16, more preferably 13 to 15.
  • emulsifier examples include polyoxyethylene alkylamine, and preferably polyoxyethylene alkylamine whose alkyl group has 10 to 18 carbon atoms.
  • fatty acid alkali metal salts particularly saturated or unsaturated fatty acid alkali metal salts having 8 to 24 carbon atoms, particularly 10 to 22 carbon atoms
  • capric acid examples include sodium salts and potassium salts of saturated or unsaturated fatty acids such as lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, oleic acid, erucic acid, linoleic acid, and linolenic acid.
  • sodium salts and potassium salts of fatty acids produced from edible fats and oils can also be preferably used.
  • fatty acid alkali metal salt in particular, an alkali metal salt of a fatty acid containing 25% by weight or more of at least one type selected from unsaturated fatty acids having 14 to 22 carbon atoms, such as oleic acid, erucic acid, linoleic acid, and linolenic acid.
  • unsaturated fatty acids having 14 to 22 carbon atoms such as oleic acid, erucic acid, linoleic acid, and linolenic acid.
  • emulsifier esters of glycerin and the aforementioned fatty acids can also be suitably used, and esters of stearic acid can be particularly preferably used.
  • emulsifiers may be used alone or in combination of two or more.
  • the mixing ratio of the droplet condensation accelerator and emulsifier is 40/1 to 1/1 by weight (droplet condensation accelerator/emulsifier), especially 20 Approximately /1 to 2/1 is suitable.
  • a neutralizing amine having a pH adjusting function may be used in combination, and the effect of reducing the corrosiveness in the system can be obtained by using the neutralizing amine in combination.
  • neutralizing amines include ammonia, monoethanolamine (MEA), cyclohexylamine (CHA), morpholine (MOR), diethylethanolamine (DEEA), monoisopropanolamine (MIPA), 3-methoxypropylamine (MOPA), Volatile amines such as 2-amino-2-methyl-1-propanol (AMP) and diglycolamine (DGA) can be used. These may be used alone or in combination of two or more.
  • the pH may be adjusted using ammonia derived from the thermal decomposition of the oxygen scavenger described below.
  • the amount of neutralizing amine added varies depending on the amount of droplet condensation accelerator used, the type of heat exchanger, etc., but it is 0.1 to 0.1 to the amount of steam in terms of water. It is preferably 50 mg/L, particularly 1 to 30 mg/L.
  • an oxygen scavenger may be used in combination with the droplet condensation accelerator, and the combined use of the oxygen scavenger can have the same effect of reducing corrosion within the system as the neutralizing amine.
  • the oxygen scavenger hydrazine derivatives such as hydrazine and carbohydrazide can be used.
  • non-hydrazine oxygen scavengers carbohydrazide, hydroquinone, 1-aminopyrrolidine, 1-amino-4-methylpiperazine, N,N-diethylhydroxylamine, isopropylhydroxylamine, erythorbic acid or its salt, ascorbic acid or Salts thereof, tannic acid or salts thereof, sugars, sodium sulfite, etc. can also be used. These may be used alone or in combination of two or more.
  • the amount of oxygen scavenger added varies depending on the amount of droplet condensation accelerator used, the type of heat exchanger, etc., but it is 0.01 to 3 mg per water equivalent steam amount.
  • L particularly preferably 0.05 to 1 mg/L.
  • the above-mentioned concomitant drug may be added to the same location as the droplet condensation accelerator, or may be added to a different location.
  • the drugs to be added may be mixed in advance and added, or may be added separately.
  • Example 1 and 2 Water-repellent film formation test on test piece] ⁇ Experimental method> The oil and fat adhering to the surface of a carbon steel test piece (STB340, 30 mm x 50 mm x 3 mm) was removed with toluene. Thereafter, the test piece was immersed in 1 L of a test solution consisting of an aqueous solution of the acid shown in Table 1, a water-repellent film-forming substance (oleylpropylene diamine), and a reducing agent (erythorbic acid), and maintained at 70°C. Thereafter, the test piece was removed from the test solution, rinsed in pure water for about 1 minute, and then dried with a hair dryer.
  • a test solution consisting of an aqueous solution of the acid shown in Table 1, a water-repellent film-forming substance (oleylpropylene diamine), and a reducing agent (erythorbic acid)
  • Example 1 ⁇ Summary> A tube made of carbon steel (STB340) with an outer diameter of 19 mm, an inner diameter of 14.4 mm, and a length of 1530 mm was inserted into the axial center of a cylindrical water passage member with a diameter (inner diameter) of 31 mm and a length of 1300 mm. Then, a water-repellent film-forming treatment liquid was passed through the water passage space between the outer peripheral surface of the tube and the inner peripheral surface of the water-permeable member to form a water-repellent film.
  • STB340 carbon steel
  • the tube with the water-repellent film formed thereon was installed in a heat exchange test device, droplet-like condensation accelerator-added steam was passed around the outside of the tube, and cooling water was passed inside the tube to measure thermal conductivity.
  • a water-repellent film-forming treatment solution having the following composition in the tank was circulated in the above-mentioned water passage space for 3 hours.
  • the water-repellent film forming treatment liquid was introduced into the space from one longitudinal end of the space, flowed out from the other end, and returned to the tank.
  • the circulation flow rate of the water-repellent film forming treatment liquid was 5.5 L/min (about 0.8 m/min as a linear flow rate).
  • the heat exchanger 10 includes a cylindrical heat-insulating column 11 and a tube 12 that has been subjected to the film formation process and is inserted through the axial center of the column 11. A space between the outer circumferential surface of the tube 12 and the inner circumferential surface of the column 11 is a space for water vapor to flow.
  • a chemical injection part 8 for a droplet-like condensation accelerator is provided in the pipe 2.
  • the pipes 2 and 4 and the column 11 are provided with pressure gauges P1, P2, and P3.
  • temperature sensors T1 to T5 are provided to measure the inlet temperature of the cooling water, the outlet temperature of the cooling water, the inlet temperature of the steam, the outlet temperature of the steam, and the internal temperature of the steam heat exchanger.
  • a flow meter F is provided to measure the flow rate of cooling water flowing inside the tube 12.
  • a 0.013 wt% aqueous solution of oleylpropylene diamine (OLDA) was used as a droplet condensation promoter aqueous solution, and was continuously added so that the amount of amine added to the steam was 0.4 mg/L.
  • This OLDA aqueous solution was prepared in a 30 L tank and added from the chemical injection part 8 in FIG. 1 while constantly stirring with a stirrer to prevent separation. Furthermore, monoethanolamine was added to this tank so that the pH of the drain water was about 9.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Preventing Corrosion Or Incrustation Of Metals (AREA)
  • Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)

Abstract

L'invention concerne un procédé d'amélioration de l'efficacité de transfert de chaleur d'un échangeur de chaleur par la formation d'un film hydrophobe sur la surface de l'échangeur de chaleur, ledit procédé étant caractérisé en ce que le film hydrophobe est formé par la mise en contact de l'échangeur de chaleur avec un liquide comprenant un acide et une substance de formation de film hydrophobe. L'invention concerne en outre un procédé d'amélioration de l'efficacité de transfert de chaleur d'un échangeur de chaleur par la formation d'un film hydrophobe sur la surface de l'échangeur de chaleur, ledit procédé étant caractérisé en ce que le film hydrophobe est formé par la mise en contact de l'échangeur de chaleur avec un liquide contenant une substance acide de formation de film hydrophobe.
PCT/JP2023/009849 2022-05-24 2023-03-14 Procédé d'amélioration d'efficacité de transfert de chaleur d'échangeur de chaleur WO2023228525A1 (fr)

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5135641A (ja) * 1974-09-21 1976-03-26 Naado Kenkyusho Kk Sansenekinokinzokuzairyonitaisurufushokuyokuseihoho
JPH02179884A (ja) * 1988-12-28 1990-07-12 Sumitomo Metal Ind Ltd 化成処理性の良好な亜鉛系めっき鋼板の製法
JP2002285361A (ja) * 2001-03-22 2002-10-03 Chubu Kiresuto Kk マグネシウム含有金属材用防食剤および防食処理法
JP2006322627A (ja) * 2005-05-17 2006-11-30 Toshiba Corp 熱交換器とその製造方法、ならびに原子炉格納容器システム
JP2019158255A (ja) * 2018-03-14 2019-09-19 栗田工業株式会社 蒸気の凝縮方法

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5135641A (ja) * 1974-09-21 1976-03-26 Naado Kenkyusho Kk Sansenekinokinzokuzairyonitaisurufushokuyokuseihoho
JPH02179884A (ja) * 1988-12-28 1990-07-12 Sumitomo Metal Ind Ltd 化成処理性の良好な亜鉛系めっき鋼板の製法
JP2002285361A (ja) * 2001-03-22 2002-10-03 Chubu Kiresuto Kk マグネシウム含有金属材用防食剤および防食処理法
JP2006322627A (ja) * 2005-05-17 2006-11-30 Toshiba Corp 熱交換器とその製造方法、ならびに原子炉格納容器システム
JP2019158255A (ja) * 2018-03-14 2019-09-19 栗田工業株式会社 蒸気の凝縮方法

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