WO2008041400A1 - Method of inhibiting frothing of seawater cooling water system - Google Patents

Abstract

A method of inhibiting the frothing of a seawater cooling water system, characterized by adding a higher aliphatic tertiary amine to the seawater cooling water system containing a chlorine generator added thereto.

Description

 Specification

 Method of suppressing foaming in seawater cooling water system

 Technical field

 The present invention relates to a seawater cooling water system foaming suppression method. The present invention can efficiently suppress foaming generated in a seawater cooling water system in which a chlorine generator is added to prevent the attachment of marine organisms.

 Background art

 [0002] In thermal power plants, steel mills, oil refineries, petrochemical plants, and other chemical factories that use seawater as cooling water, marine organisms adhere to the cooling water system, resulting in reduced cooling functions. Problems such as corrosion of metal materials of cooling water systems such as water conduits occur. These problems have generally been addressed by adding marine organism anti-adhesives and anti-corrosion agents to the cooling water system.

[0003] Conventionally, as marine organism adhesion preventing agents that are widely used, chlorine generators such as sodium hypochlorite, chlorine dioxide, and chlorine gas can be mentioned. However, when these chlorine generators are added to the cooling water system as described above, corrosion of the structure of the cooling water system and foaming (foaming) due to reaction with microorganisms and organic substances in the sea water may cause problems. there were. Specifically, foaming adversely affects the operation of the cooling water system and can cause product quality degradation at manufacturing plants.

 [0004] In an aqueous system in which foaming is a problem, a silicon-based antifoaming agent is generally used.

 In addition, in order to suppress foaming of quaternary ammonium compounds known as agricultural chemicals and industrial fungicides, it is also known to use a higher aliphatic amine in combination with a silicon-based antifoaming agent (Japanese Patent No. 2713509). (See Patent Document 1)).

Japanese Patent Laid-Open No. 10-120508 (Patent Document 2) discloses that when a higher aliphatic tertiary amine or a salt thereof is added to a seawater cooling water system to control damage caused by marine organisms, A method for measuring transparency and controlling the addition of ammine based on the change is described, and it is stated that higher aliphatic tertiary amines are less likely to foam in seawater than other amines. However, the above prior art does not describe that higher aliphatic tertiary amines are effective in preventing foaming due to reaction with microorganisms and organic substances in seawater. It was not known.

[0005] Patent Document 1: Japanese Patent No. 2713509

 Patent Document 2: JP-A-10-120508

 Disclosure of the invention

 Problems to be solved by the invention

[0006] An object of the present invention is to provide a seawater cooling water system foaming suppression method that can efficiently suppress foaming that occurs in a seawater cooling water system or the like in which a chlorine generator is added to prevent adhesion of marine organisms.

 Means for solving the problem

[0007] The inventors of the present invention have conducted extensive research to solve the above problems, and as a result, added a specific higher aliphatic tertiary amine to a seawater cooling water system in which foaming has occurred by adding a chlorine generator. By adding, it was found that foaming can be efficiently suppressed, and the present invention has been completed.

[0008] Forcibly, according to the present invention, a higher aliphatic tertiary ammine is added to a seawater cooling water system to which a chlorine generator is added to suppress foaming generated in the seawater cooling water system. A method for suppressing foaming in a seawater cooling water system is provided.

 The invention's effect

 [0009] According to the present invention, it is possible to provide a foaming suppression method for a seawater cooling water system that can efficiently suppress foaming that occurs in a seawater cooling water system or the like in which a chlorine generator is added to prevent adhesion of marine organisms. .

 The present invention can be applied to foaming generated in a cooling water system of a thermal power plant, a steel mill, an oil refinery, a petrochemical plant, and other chemical factories, and is extremely useful industrially.

 Brief Description of Drawings

FIG. 1 is a schematic diagram of a defoaming test circulation device used in Test Example 1.

 FIG. 2 is a diagram showing the change over time of the bubble height in Test Example 1.

Explanation of symbols [0011] 1 Circulator for defoaming test

 2 containers

 3 Pipe heater

 4 Tripod Sunoko

 5 Test seawater

 6 pumps)

 7 Pipe

 8 Pipe outlet

 BEST MODE FOR CARRYING OUT THE INVENTION

[0012] The seawater cooling water system foaming suppression method of the present invention is characterized in that a higher aliphatic tertiary amine is added to a seawater cooling water system to which a chlorine generator is added to suppress foaming generated in the seawater cooling water system. And

 In the present invention! “Seawater cooling water system to which a chlorine generator is added” means a seawater cooling water system to which a chlorine generator is added for the purpose of preventing adhesion of marine organisms, for example.

 Therefore, the present invention uses thermal water as cooling water and adds a chlorine generator for the purpose of preventing the attachment of marine organisms, thermal power plants, steelworks, oil refineries, petrochemical plants, other It can be suitably used in a seawater cooling water system such as a chemical factory.

In the present invention, examples of the higher aliphatic tertiary amine added to the seawater cooling water system include known amines having 12 to 24 carbon atoms. Specifically, N, N-dimethyldodecylamine (=? ^, N-dimethyllaurylamine), N, N-dimethyltetradecylamine, N, N-dimethylpentadecylamine, N, N— Dimethylhexadecylamine, N, N-dimethylpentadecylamine, N, N-dimethyloctadecylamine, N, N-dimethyldocosylamine (= N, N-dimethylbehylamine) and N, N— And dimethyl coconut alkylamine. These can use one kind or a mixture of two or more kinds (mixed alkylamine).

[0014] Examples of the mixed alkylamine include N, N-dimethyl beef tallow alkylamine and N, N-dimethyl-cured beef tallow alkylamine. These amines are produced from beef tallow by known means, saturated or unsaturated linear aliphatics having 12 to 18 carbon atoms. It means a mixture of amines in which hydrocarbon groups occupy the main component.

 In the method of the present invention, among the above amines, N, N-dimethyllaurylamine, N, N-dimethylberylamine, and N, N-dimethyl beef tallow anolenoleamine are used in terms of foaming suppression effect. Especially preferred.

[0015] The higher aliphatic tertiary amines are in the form of salts such as hydrochloric acid, hydrobromic acid, nitric acid, sulfuric acid, phosphoric acid, formic acid, acetic acid, oleic acid, naphthenic acid, adipic acid, lactic acid, citrate and saccharin. It may be used in a state.

 For example, in the case of acetate, it can be obtained by reacting a higher aliphatic tertiary amine with an equimolar amount of acetic acid.

 When these are added to the seawater cooling water system, these compounds may be appropriately diluted or dissolved in seawater or fresh water to obtain the desired concentration.

In the present invention, the concentration of the higher aliphatic tertiary amine added to the seawater cooling water system depends on the effective chlorine concentration of the chlorine generator present in the seawater cooling water system, the water temperature, etc. in terms of, 0. 005~5mgZ liter force ^s preferably, 0. 01~: LmgZ liter is particularly preferred arbitrariness.

 [0017] As the chlorine generator in the seawater cooling water system to which the chlorine generator of the present invention is added, known chlorine generators used for the purpose of preventing adhesion of marine organisms, such as hypochlorous acid and salts thereof, Dichloroisocyanuric acid and its salts, salach liquid (Ca (ClO)), dioxide

 2 Chlorine and chlorine gas obtained by electrolysis of seawater.

 [0018] In the seawater cooling water system foaming suppression method of the present invention, the effective concentration of the chlorine generator present in the seawater cooling water system is 0.01 to LOmgZ liter, preferably 0.05 to 5 mgZ, in terms of effective chlorine concentration. When it is liters, foaming can be efficiently suppressed.

 [0019] The seawater cooling water system foaming suppression method of the present invention introduces a compound that generates iron ions in water together with a higher aliphatic tertiary amine into the seawater cooling water system at the same time. Corrosion of metal materials of structures such as water pipes can be prevented.

Compounds that generate iron ions in water include compounds that are soluble in water and can form iron ions in water, such as ferrous sulfate, ferrous chloride, and ferrous sulfate ammonium. Is mentioned. In addition, iron ion generation as described in Japanese Patent Publication No. 54-40472. Even iron ions generated by raw equipment.

 [0020] When these are added to the seawater cooling water system, these compounds may be appropriately diluted or dissolved in seawater or fresh water so as to have a desired concentration.

 The iron ion concentration is preferably from 0.01 to 3 mg Z liters in view of the corrosion prevention effect of the metal material, and from 0.03 to Lmg / Lits.

 [0021] In the seawater cooling water system foaming suppression method of the present invention, for example, a chlorine generator is intermittently added, and a higher aliphatic tertiary amine is added within 1 to 2 hours after the addition of the chlorine generator. Further, there is a method of repeatedly adding a chlorine generator within 10 to 180 minutes after the addition of the higher aliphatic tertiary amine. This method is preferable because an effective foaming suppression effect can be obtained, and corrosion of the seawater cooling water system piping hardly occurs. For example, a similar effect can be expected by adding a chlorine generator and a higher aliphatic tertiary amine simultaneously to a seawater cooling system in which the residual chlorine concentration at the time of discharge is controlled to be below the detection limit. preferable.

 Example

 [0022] The present invention will be specifically described with Preparation Examples and Test Examples, but the present invention is not limited to these Preparation Examples and Test Examples.

[0023] Preparation Example 1 (Preparation of aqueous sodium hypochlorite solution)

 A 12% sodium hypochlorite aqueous solution was diluted with pure water to prepare a sodium hypochlorite aqueous solution having an effective chlorine concentration of 2000 mg Z liters.

[0024] Preparation Examples 2 to 7

 The following various amines were each reacted with an equimolar amount of acetic acid to prepare an aqueous acetate salt solution of amine having a concentration of 2000 mgZ.

 (Preparation Example 2) N, N-dimethyl tallow alkylamine (C = 12 to 18)

 [Dimethylalkyl tertiary amine]

 Product name: Armin DMTD

 (Preparation Example 3) N, N-dimethyllaurylamine (C = 12)

 [Dimethylalkyl tertiary amine]

Product name: Armin DM 12D (Preparation Example 4) N, N-dimethylbe-lamine (C = 22)

 [Dimethylalkyl tertiary amine]

 Product name: Armin DM22D (Preparation Example 5) Dimethyloctylamine (C = 8)

 [Dimethylalkyl tertiary amine]

 Product name: Farmin DM0898, manufactured by Kao Corporation

 (Preparation Example 6) Di-cured tallow alkylamine (C = 14-18)

 [Dialkyl secondary amine]

 Product of Lion's Akuzo, product name: Armin 2HT

 (Preparation Example 7) Octadecylamine (C = 18)

 [Alkyl primary amine]

 Wako Pure Chemical Industries, Reagent

[0025] Test Example 1 (Bubble height confirmation test)

 Using the defoaming test circulation device 1 shown in FIG. 1, a foam height confirmation test was carried out by the seawater cooling water system foaming suppression method of the present invention.

 The sodium hypochlorite aqueous solution of Preparation Example 1 was added to seawater so that the effective chlorine concentration of sodium hypochlorite was 1. OmgZ liter to obtain 2 liters of test seawater (pH 8.5).

 Next, a PVC cylindrical container 2 (inner diameter 14 cm, height), equipped with a pipe heater 3 (manufactured by Yoko Electric Manufacturing Co., Ltd., voltage 100 V, power consumption 500 W) and tripod sword 4 (outer diameter 12 cm, height 7 cm) The test seawater 5 was poured into 30 cm) and heated with a pipe heater 3 so that the water temperature of the test seawater 5 was 0 ° C. Next, an aqueous solution of the amine salt of Preparation Example 2 was added to the test seawater with a micropipette so that the amine concentration was 0.1 mgZ liter, and lightly stirred.

[0026] After that, the pump 6 (Iwakine earth magnet pump, model: MD-30R-N), which was adjusted in advance so that the circulation flow rate became 24 liters Z, was operated, and the bottom force of the container 2 also sucked up the test seawater 5, The test sea water 5 is dropped from the position 8.5 cm above the reference liquid level (pipe outlet 8) via pipe 7 (inner diameter 13 mm, path length approx. 70 cm, the maximum point force of the pipe is 20 cm height between the reference liquid levels). The test seawater 5 was circulated for 300 seconds (arrow in the figure). Immediately after starting circulation After 10 seconds, 30 seconds, 60 seconds, 90 seconds, 120 seconds, 180 seconds, 180 seconds, 240 seconds and 300 seconds, the foam height (height from the reference liquid level to the top of the foam) is measured. did.

 A foam height confirmation test was carried out in the same manner as described above except that the aqueous solution of the amine salt of Preparation Example 2 was added in place of the aqueous solution of the amine salt of Preparation Examples 3 to 7, respectively.

 In addition, a foam height confirmation test was conducted in the same manner as described above except that an aqueous solution of acetate amine was not added as a blank.

 Figure 2 shows the results obtained. In the figure, the upper and lower sides of “參” from 0 to 300 seconds show Preparation Example 3 and Preparation Example 2, respectively, and the upper and lower sides of “參” from 300 to 600 seconds show Preparation Example 2 and Preparation Example 3, respectively.

 From the results of FIG. 1, it can be seen that Preparation Examples 2 to 4 show the most excellent foam suppression effect before and after circulation stoppage. In addition, in Preparation Examples 5 and 6, the amount of foaming during the circulation was higher than that of the blank, and it was found that more bubbles remained than the blank before and after the circulation was stopped. In Preparation Example 7, bubbles with relatively high viscosity were generated, and the bubbles adhered to the wall surface of the container.

 [0028] Test Example 2 (Defoaming effect confirmation test in a refinery)

 In order to prevent marine organisms from adhering to the water system, chlorination is performed by adding sodium hypochlorite so that the effective chlorine concentration is 0.1 mgZ liters near the intake. The test was conducted in an aqueous system (water amount: 5000 tons, Z hours). Foaming was observed at the outlet before the test.

 That is, the agent of Preparation Example 2 was added near the outlet of the seawater cooling water system so that the concentration of the higher aliphatic tertiary amine was 0.1 mgZ liter, and the state of foaming at the outlet after 1 hour was observed. did.

 The seawater collected before the test had a lot of diatoms (Eucampia. Sp), and the water quality was as follows.

[0029] [Seawater quality]

 Suspended suspension (ss): 30mgZ liter

 COD: 4.5mgZ liter

 pH: 8.1

[0030] By adding the agent of Preparation Example 2, the generated foam could be suppressed. In addition, since a large amount of foam was observed when a large amount of diatoms were present, the mucous that was also secreted by the diatom power damaged by chlorination was greatly involved in the generation of foam. Conceivable.

Claims

The scope of the claims  [1] A method for suppressing foaming of a seawater cooling water system, wherein a high-grade aliphatic tertiary amine is added to a seawater cooling water system to which a chlorine generator is added to suppress foaming generated in the seawater cooling water system [2] The seawater cooling water system according to claim 1, wherein the higher aliphatic tertiary amine is N, N-dimethyllaurylamine, N, N-dimethylbelamin or N, N-dimethyl tallow alkylamine. Foaming suppression method. [3] The method for inhibiting foaming of a seawater cooling water system according to claim 1 or 2, wherein the concentration of the higher aliphatic tertiary amine is 0.005 to 5 mgZ liter. [4] The seawater cooling water system foaming suppression method according to any one of claims 1 to 3, wherein the effective concentration of the chlorine generator is 0.01 to LOmgZ liters in terms of effective chlorine concentration.