Pollution control agent for circulating cooling water system and use method

Abstract

The invention discloses a fouling control agent for a circulating cooling water system. The fouling control agent comprises an agent A and an agent B, the agent A is trichloroisocyanuric acid, and the agent B comprises the following raw material components in percentage by mass: 20-30% of geramine, 10-20% of isothiazolinone, 5-15% of alkyl epoxy carboxylate and the balance of deionized water, and the sum of the mass percentages of the components is 100%. The invention also discloses a use method of the fouling control agent, which specifically comprises the following steps: the agent B and the agent A are sequentially added into a circulating cooling water system, the time interval of adding the agent B and the agent A is 5-48 hours, and the operation time after adding the agent B is 8-40 hours. The fouling control agent for the circulating cooling water system has good bactericidal activity, has good decomposition and stripping effects on biological slime, can be used for rapidly removing the biological slime of the circulating cooling water system, and also has the effects of cleaning dirt on the metal surface and improving the heat exchange rate of equipment.

Description

Technical Field

[0001] The invention belongs to the technical field of water treatment agent preparation, and in particular relates to a fouling control agent for a circulating cooling water system, and also relates to a method for using the fouling control agent. Background Art

[0002] Industrial circulating cooling water is circulated and concentrated in the system for a long time, resulting in the continuous enrichment of nutrients in the water body that are conducive to the growth of microorganisms, making it easy for microorganisms to multiply in large numbers. At the same time, the large-scale reproduction of microorganisms will also produce a large amount of biological slime in the circulating water system. Biological slime will not only cause the cooling water quality to deteriorate sharply, but also easily deposit in the cooling tower and heat exchange equipment, isolating the protective effect of the agent on the metal, so that the agent cannot play its due corrosion and scale inhibition effect, and can cause corrosion of metal equipment in the cooling water system. In severe cases, it can also block the pipeline, causing great harm to industrial production. In order to avoid such situations, the most effective way is to add fungicides to inhibit the reproduction of microorganisms in the control system.

[0003] Commonly used fungicides are divided into two categories: oxidizing and non-oxidizing fungicides. At present, oxidizing fungicides use more chlorine-containing fungicides, such as sodium hypochlorite, chlorine dioxide, chlorine gas, etc., but they all have problems such as high risk, poor effect in alkaline environment, and easy to produce drug resistance. Trichloroisocyanuric acid, as a new generation of low-toxic, broad-spectrum, and highly efficient fungicide, can effectively kill microorganisms for a long time. At the same time, it can also avoid the transportation safety hazards and leakage risks that may be faced when using liquid chlorine, as well as the problem of unstable bactericidal effect caused by pH fluctuations in liquid chlorine during the sterilization process. Moreover, its bactericidal effect fully meets the requirements of the circulating cooling water system for various microbial control indicators. However, non-oxidizing fungicides have the disadvantages of large dosage of single-component fungicides, single bactericidal varieties, poor killing effect, and easy to produce drug resistance. The composite formula with synergistic effects has a synergistic effect relative to the single components, and can overcome the weaknesses of single-component fungicides and reduce costs.

[0004] A Chinese patent (application number: 200910100123.1, publication number: CN101578997A, publication date: 2009-11-18) discloses a composite fungicide, which contains tribenzylphenylphosphonium chloride, dithiocyanomethane and copper sulfate. Although phosphorus-containing cations are used to replace nitrogen-containing cations in quaternary ammonium salts, the bactericidal effect of quaternary phosphonium salts is better than that of quaternary ammonium salts from a structural analysis, but the introduction of phosphorus and sulfur elements in the fungicide will further increase the eutrophication of water bodies, and the indirect generation of H2S will aggravate the metal equipment Problems such as corrosion and safety in use occur; Chinese patent (application number: 200510025284.0, publication number: CN1853468A, publication date: 2006-11-01) discloses a quaternary ammonium salt composite high-efficiency biocide, the selected quaternary ammonium salt cannot be shared with chlorophenol biocide, and should not be shared with anionic surfactants. When there are a large number of Ca, Mg and Fe metal ions in the circulating water, the bactericidal effect of the quaternary ammonium salt can be reduced, and the quaternary ammonium salt is easy to foam and needs to be used together with a defoamer, which is not conducive to industrial production and easily causes environmental pollution.

[0005] Although there are many types of slime stripping agents at present, their slime stripping performance and environmental benefits still cannot meet the requirements of current water treatment. Foreign research on slime stripping agents mainly focuses on the development of environmentally friendly, biodegradable, low-cost water treatment agents. Domestic slime stripping agents for circulating water are mostly cationic surfactants. Although their stripping effect is good, they have some defects. A Chinese patent (application number: 200510025391.3, publication number: CN1853473A, publication date: 2005-04-25) discloses a bactericidal algaecide that is effective in stripping microbial slime, which contains isothiazolinone, dodecyl dimethyl benzyl ammonium chloride, polyacrylic acid, etc. However, bactericidal algaecides are generally used in higher dosages and may affect other water treatment agents during use; a Chinese patent (application number: 201010201250.3, publication number: CN101849547A, publication date: 2010-10-06) discloses a highly effective bactericide, which is a water treatment agent product containing three main components: isothiazolinone, trimethylolnitromethane and dibromoethanol. The disadvantage is that trimethylolnitromethane will slowly decompose and release formaldehyde in a slightly alkaline solution, shortening its service life, so it is not suitable for slightly alkaline circulating cooling water.

[0006] In order to kill microorganisms and remove biological slime in circulating cooling water systems, existing bactericides or slime stripping agents need to be synthesized or compounded with a large amount of chlorine, phosphorus and sulfur-containing chemicals, which not only aggravates the eutrophication of water bodies and the corrosion of metal equipment, but also causes serious pollution to the environment and the difficulty in treating discharged wastewater. Therefore, it is urgent to develop a circulating cooling water system fouling control agent that can efficiently and safely strip biological slime in circulating cooling water systems and has both bactericidal and environmental protection properties. Summary of the invention

[0007] The object of the present invention is to provide a fouling control agent for a circulating cooling water system, which has good bactericidal properties and good decomposition and stripping effects on biological slime.

[0008] Another object of the present invention is to provide a method for using a fouling control agent for a circulating cooling water system, which solves the problem that the continuous dosing method in the circulating water system requires a large amount of agent and microorganisms are prone to develop drug resistance.

[0009] The technical scheme adopted by the present invention is that the fouling control agent for the circulating cooling water system includes agent A and agent B; agent A is trichloroisocyanuric acid, and agent B is composed of the following raw material components by mass percentage: 20-30% of chlorhexidine, 10-20% of isothiazolinone, 5-15% of alkyl epoxy carboxylate, and the rest is deionized water, and the sum of the mass percentages of the above components is 100%.

[0010] The present invention is also characterized in that:

[0011] The dosage of agent A in the circulating cooling water system is 0.5-5.0 mg / L; the dosage of agent B in the circulating cooling water system is 10-150 mg / L.

[0012] The alkyl epoxy carboxylate is any one of alkyl decacyclyloxy carboxylate, alkyl dodecacyclyloxy carboxylate, alkyl pentacyclyloxy carboxylate, and alkyl eicoscyclyloxy carboxylate.

[0013] The preparation method of Agent B is as follows:

[0014] Step 1: Mix deionized water and alkyl epoxy carboxylate, stir for 5-10 minutes at a stirring rate of 250-300 r / min to obtain an alkyl epoxy carboxylate solution;

[0015] Step 2: Add benzyl alcohol to the alkyl epoxy carboxylate solution obtained in step 1, stir for 20-30 minutes at room temperature at a stirring rate of 250-300 r / min to obtain a mixed solution;

[0016] Step 3: Add isothiazolinone and deionized water to the mixed solution obtained in step 2, stir for 10-15 minutes at room temperature, and stir at a rate of 150-200 r / min to obtain a mixed agent;

[0017] Step 4: Add the mixed reagent obtained in step 3 into a centrifugal filter and filter for 10-15 minutes. After filtration, take the supernatant and package it with a packaging machine to obtain agent B in the circulating cooling water system fouling control agent.

[0018] The preparation method of alkyl epoxy carboxylate is specifically as follows:

[0019] Dissolve fatty alcohol polyoxyethylene ether and sodium chloroacetate in anhydrous ethanol at a molar ratio of 1:1.0-1.5, stir to fully dissolve, then keep the reaction solution at 45-50°C and stir for 30 minutes, and slowly add sodium hydroxide in batches within 0.5-1.0 hours, and finally control the reaction temperature at 50-55°C, react for 3-4 hours, then increase the temperature to 55-60°C, react for 0.5-1.0 hours, and then use anhydrous ethanol as a diluent, cool the reaction mixture in ice water, filter, and distill to obtain alkyl epoxy carboxylate.

[0020] The molar ratio of fatty alcohol polyoxyethylene ether, sodium chloroacetate and sodium hydroxide is 1:1.0-1.5:1.0-1.3.

[0021] Another technical solution adopted by the present invention is a method for using a fouling control agent for a circulating cooling water system, specifically: adding agent B and agent A to the circulating cooling water system in sequence, the time interval between adding agent B and agent A is 5-48 hours, and the operating time after adding agent B is 8-40 hours.

[0022] The beneficial effects of the present invention are as follows: the high-efficiency, fast, phosphorus-free and low-chlorine circulating cooling water system fouling control agent of the present invention is composed of low-chlorine oxidizing trichloroisocyanuric acid (Agent A) and phosphorus-free environmentally friendly non-oxidizing composite bactericidal biological slime stripping agent (Agent B). Agent A effectively solves the problems of existing chlorine-containing oxidizing bactericides, such as high danger, poor effect in alkaline environment, and easy to produce drug resistance; Agent B solves the problem that non-oxidizing bactericide compound agents are not suitable for use with anionic surfactants and reduce the bactericidal effect of quaternary ammonium salts. In addition, the method of using the circulating cooling water system fouling control agent solves the problem that the impact dosing method of the existing circulating water system is difficult to have the dual functions of stripping and sterilization, and the problem that the continuous dosing method uses a large amount of drugs and microorganisms are prone to produce drug resistance. The circulating cooling water system fouling control agent not only has a simple and safe preparation process, but also has good bactericidal properties and a good decomposition and stripping effect on biological slime. It can be used to quickly remove biological slime from the circulating cooling water system and also has the functions of cleaning dirt on the metal surface and improving the heat exchange rate of equipment. It is suitable for industrial circulating water systems, urban geothermal heating systems, pipelines, oil well production equipment and other water circulation systems with local high temperatures. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Infrared spectra characterization spectra of characteristic functional groups in AEC-10, AEC-12, AEC-15 and AEC-20;

[0024] Figure 2 This is the corrosion inhibition performance diagram of agent B in the fouling control agent of the circulating cooling water system on carbon steel;

[0025] Figure 3This is a graph showing the bactericidal efficiency of fouling control agents in circulating cooling water systems. DETAILED DESCRIPTION

[0026] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0027] The fouling control agent for a circulating cooling water system of the present invention comprises an agent A and an agent B, and the agent A and the agent B are stored separately; wherein the agent A is trichloroisocyanuric acid, and the amount used in the circulating water system is 0.5-5.0 mg / L, preferably 0.5-2.0 mg / L. The agent B is composed of the following raw material components by mass percentage: 20-30% of chlorhexidine, 10-20% of isothiazolinone, 5-15% of alkyl epoxy carboxylate, and the rest is deionized water, and the sum of the mass percentages of the above components is 100%;

[0028] The alkyl epoxy carboxylate is a straight-chain alkyl epoxy carboxylate, preferably any one of alkyl decacyclyloxy carboxylate (AEC-10), alkyl dodecacyclyloxy carboxylate (AEC-12), alkyl pentacyclyloxy carboxylate (AEC-15), and alkyl eicoscyclyloxy carboxylate (AEC-20), more preferably alkyl decacyclyloxy carboxylate (AEC-10).

[0029] The preparation method of alkyl epoxy carboxylate is specifically as follows:

[0030] Dissolve fatty alcohol polyoxyethylene ether and sodium chloroacetate in anhydrous ethanol at a molar ratio of 1:1.0-1.5, stir to fully dissolve, then maintain the reaction solution at 45-50°C for 30 minutes for stirring and dissolving, and slowly add sodium hydroxide in batches within 0.5-1.0 hours, and finally control the reaction temperature at 50-55°C, react for 3-4 hours, then increase the temperature to 55-60°C, react for 0.5-1.0 hours, synthesize AEC crude product, and then use anhydrous ethanol as a diluent, cool the reaction mixture in ice water, filter, and distill to obtain alkyl epoxy carboxylate;

[0031] The molar ratio of fatty alcohol polyoxyethylene ether, sodium chloroacetate and sodium hydroxide is 1:1.0-1.5:1.0-1.3;

[0032] The preparation method of the fouling control agent B in the circulating cooling water system of the present invention is specifically implemented according to the following steps:

[0033] Step 1: Mix deionized water and alkyl epoxy carboxylate, stir for 5-10 minutes at room temperature, and stir at a rate of 250-300 r / min to obtain an alkyl epoxy carboxylate solution;

[0034] The mass fraction of the alkyl epoxy carboxylate solution is 5-15%;

[0035] Step 2: Add benzyl alcohol to the alkyl epoxy carboxylate solution obtained in step 1, stir for 20-30 minutes at room temperature at a stirring rate of 250-300 r / min to obtain a mixed solution;

[0036] Step 3: Add isothiazolinone and deionized water to the mixed solution obtained in step 2, stir for 10-15 minutes at room temperature, and stir at a rate of 150-200 r / min to obtain a mixed agent;

[0037] Step 4: Add the mixed reagent obtained in step 3 into a centrifugal filter and filter for 10-15 minutes. After filtration, take the supernatant and package it with a packaging machine to obtain agent B in the circulating cooling water system fouling control agent.

[0038] The functions of the components in the fouling control agent of the present invention are as follows:

[0039] Trichloroisocyanuric acid: a safe low-chlorine oxidizing fungicide that can effectively kill microorganisms such as bacteria, viruses, fungi and spores. The oxidizing substance X (hypochlorous acid) in its hydrolysis product has a disinfecting and sterilizing effect.

[0040] Chlorhexidine: A quaternary ammonium salt cationic surfactant with good dispersing and biological slime removal effects.

[0041] Isothiazolinone: It is mainly composed of 5-chloro-2-methyl-4-isothiazolin-3-one and 2-methyl-4-isothiazolin-3-one. It can kill bacteria by breaking the bonds between bacteria and algae proteins. It has a strong inhibitory and killing effect on common bacteria, fungi, algae, etc. It has high killing efficiency, good degradability, no residue, safe operation, good compatibility, strong stability, and low cost of use. It is miscible with chlorine and most anionic, cationic and non-ionic surfactants. At high doses, isothiazolinone has a significant effect on biological slime stripping.

[0042] Alkyl epoxy carboxylate: Phosphorus-free nonionic surfactant, non-toxic, chlorine-resistant, temperature-resistant, and with excellent scale inhibition, slow release, and bactericidal properties. It has good thermal stability and scale inhibition in cooling water systems with high pH, ​​high alkalinity, high hardness, and high concentration ratios, and can clean dirt on metal surfaces and improve the heat exchange rate of equipment.

[0043] The method for using the fouling control agent for a circulating cooling water system of the present invention is specifically as follows: adding agent B and agent A to the circulating cooling water system in sequence, wherein agent A is trichloroisocyanuric acid and agent B is a bactericidal biological slime stripping agent; the dosage of agent A in the circulating water system is 0.5-5.0 mg / L, preferably 0.5-2.0 mg / L; the dosage of agent B in the circulating water system is 10-150 mg / L, preferably 30-100 mg / L.

[0044] The time interval between adding agent B and agent A is 5-48h, preferably 8-36h;

[0045] The operation time after adding agent B is 8-40h, preferably 8-32h;

[0046] After adding agent B and running for a period of time, agent A can be added (i.e., repeating the steps of adding agent B and agent A in sequence in the method of the present invention) to continuously remove biological slime and microorganisms in the circulating cooling water system. Studies have found that controlling the time of adding agent A and agent B within the above preferred range can achieve better stripping effects.

[0047] The method of the present invention first adds agent B of the non-oxidative circulating cooling water system fouling control agent with biological slime stripping effect into the circulating cooling water, and then adds an oxidative bactericide (agent A) with bactericidal or bacteriostatic effect. Since the oxidative bactericide kills bacteria quickly, it is easier to kill free bacteria stripped by the non-oxidative bactericide, thereby reducing the deposition of slime on the equipment and inner wall of the pipeline of the circulating cooling water system.

[0048] Example 1

[0049] The preparation method of phosphorus-free sustained-release alkyl epoxy carboxylate is specifically as follows:

[0050] Step 1: Add 20g of fatty alcohol polyoxyethylene ether (C 12 H 25 -(OCH2CH2) 10 -OH) and 30 mL of anhydrous ethanol, followed by magnetic stirring at a stirring rate of 150 r / min, a water bath temperature of 50 ° C, and a heating time of 0.5 h to completely dissolve the fatty alcohol polyoxyethylene ether;

[0051] Step 2: Control the reaction molar ratio of fatty alcohol polyoxyethylene ether and sodium chloroacetate to 1:1.0, and evenly add sodium chloroacetate powder to the homogeneous fatty alcohol polyoxyethylene ether solution obtained above. Control the reaction molar ratio of fatty alcohol polyoxyethylene ether and sodium hydroxide to 1:1.0, and evenly add sodium hydroxide powder to the homogeneous reaction solution obtained above. The water bath temperature is 50°C, and the heating time is 1.0h, so that the fatty alcohol polyoxyethylene ether and sodium chloroacetate are fully reacted by sodium hydroxide strong base activation of hydroxyl (-OH) to generate alkyl ten ring oxygen carboxylate (AEC-10); stand at -4°C for 24h, and purify to obtain the crude product of AEC-10. Control the reaction molar ratio of AEC-10 crude product and anhydrous ethanol to 1:1.0, the water bath temperature is 45°C, and the heating time is 1.0h. After the experiment, the reaction mixed solution is cooled in an ice water bath and stood for 24-36h, filtered, and distilled to finally obtain the AEC-10 product. The preparation and purification methods of AEC-12, AEC-15 and AEC-20 are the same as those of AEC-10.

[0052] The synthetic conversion yield of AEC-10 is 85.2%, the product purity is >90%, and it is an orange-yellow viscous liquid; the synthetic conversion yield of AEC-12 is 84.5%, the product purity is >85%, and it is an orange-yellow viscous liquid; the synthetic conversion yield of AEC-15 is 83.6%, the product purity is >85%, and it is an orange-red viscous liquid; the synthetic conversion yield of AEC-20 is 83.1%, the product purity is >85%, and it is an orange-red viscous liquid.

[0053] Infrared spectroscopy characterization of characteristic functional groups in AEC-10, AEC-12, AEC-15 and AEC-20. Figure 1 The results show that the products of AEC-10, AEC-12, AEC-15 and AEC-20 have a wavelength of 3150 cm -1 、2855~2822cm -1 The stretching vibration peak of CH appeared, indicating the presence of alkyl in the compound; at 1114~1107cm -1 It is the characteristic absorption peak of epoxy group (C=O=C), which proves the effective synthesis of epoxy group in the product; 890~842cm -1 The appearance of the C=O asymmetric stretching vibration peak indicates the presence of a carboxyl group in-plane deformation vibration peak at 1650 cm -1 and 1560cm -1 The carbonyl coupling effect and the carbon-oxygen double bond stretching vibration peaks of -COOH appeared respectively, indicating that the AEC-n synthetic precursor fatty alcohol polyoxyethylene ether was carboxymethylated with sodium chloroacetate, which showed the absorption vibration peak of the presence of carboxylate. Based on the appearance of the functional group peaks in the above AEC-n products, the accuracy of the AEC-n compounds synthesized in the experiment was proved.

[0054] Example 2

[0055] The method for preparing agent B in the fouling control agent for a circulating cooling water system of the present invention comprises the following steps:

[0056] Step 1: Add an appropriate amount of deionized water to the reactor, then add 5% of alkyl epoxy carboxylate, stir at room temperature for 5 minutes at a stirring rate of 250 r / min;

[0057] Step 2: Add 20% benzyl alcohol to the solution obtained in step 1, and stir at room temperature for 20 minutes at a stirring rate of 250 r / min;

[0058] Step 3: Add 10% isothiazolinone to the solution obtained in step 2, and add deionized water to a quantitative amount after the raw materials are added, stir at room temperature for 10 minutes at a stirring rate of 150 r / min, and obtain a mixed agent after the stirring is completed;

[0059] Step 4: Add the mixed reagent obtained in step 3 into a centrifugal filter and filter for 10 minutes. After filtration, take the supernatant and package it with a packaging machine to obtain agent B of the circulating cooling water system fouling control agent.

[0060] Example 3

[0061] The corrosion inhibition performance of agent B in the fouling control agent for circulating cooling water system of the present invention on carbon steel was tested by using the rotating hanging plate method according to the method of "Determination of corrosion inhibition performance of water treatment agent GB / T 18175-2000". The experimental water sample was prepared in a 250mL volumetric flask with anhydrous calcium chloride, magnesium sulfate heptahydrate, sodium chloride, and sodium bicarbonate. The [Ca 2+ ]=265mg / L, [Mg 2+ ]=47mg / L, [HCO3 -)]=122mg / L, A20 carbon steel test piece needs pretreatment before the experiment. The carbon steel is first wiped clean with sandpaper, then scrubbed with n-hexane and anhydrous ethanol in turn to remove the oil on the surface of the steel sheet, and dried for use. Take 11 pre-prepared A20 standard test carbon steel coupons for corrosion inhibition experiment and label them 1 to 11; take 11 1000mL beakers and label them 1 to 11, among which 500ml of experimental water sample is added to beaker No. 1 as a blank control group, 500mL of experimental water sample is first added to beakers No. 2 to 8, and then the concentrations of B agent are added in sequence of 10mg / L, 20mg / L, 30mg / L, 40mg / L, 50mg / L, 60mg / L, 70mg / L, 80mg / L, 90mg / L and 100mg / L, and the corrosion inhibition efficiency of B agent is measured by RCC-Ⅲ rotating coupon corrosion monitor, the rotation rate is 60r / min and the water sample test temperature is 32℃, the reaction time is 24h, and the corrosion inhibition efficiency of B agent on carbon steel sheet is calculated by coupon mass loss method after the experiment. The results of the measurement are as follows Figure 2 As shown, with the increase of the concentration of agent B, the corrosion inhibition rate also gradually increases. When the addition concentration is 60 mg / L ~ 100 mg / L, the corrosion inhibition efficiency of agent B exceeds 35%.

[0062] Example 4

[0063] The laboratory evaluation method of biological slime stripping performance adopts the extracellular polymer method (i.e., the stripping performance of the biological slime stripping agent prepared by the method of the present invention is evaluated by analyzing the polysaccharide content and nucleic acid content). Extracellular polymers are an important component of activated sludge, and their main organic components are sugars, nucleic acids and proteins. Extracellular polymers are conducive to the aggregation of microbial cells and play an important role in the formation of stable biofilms and anaerobic granular sludge. The organic components of extracellular polymers can change the surface characteristics of bacterial flocs and the physical characteristics of granular sludge, promote the aggregation and structural stability of cells, and when the biological slime stripping agent acts on the activated sludge, the extracellular polymers are destroyed, and the organic components such as polysaccharides and nucleic acids are dispersed in the circulating cooling water, thereby achieving the stripping of biological slime. Therefore, the stripping effect of the slime stripping agent can be evaluated according to the content of organic components such as polysaccharides and nucleic acids. After the addition of the agent, the higher the content of organic components such as polysaccharides and nucleic acids, the higher the biological slime stripping performance of the agent. In the embodiment, the rotation is operated by a rotary instrument (HZ-2010 rotary constant temperature speed regulating bottle shaking cabinet, Changzhou Kaihang Instrument Co., Ltd.), and the rotation speed is controlled to be 180r / min and the temperature is 32±2°C.

[0064] The method for sampling and analyzing the content of polysaccharides and the like is as follows: filter the mixed solution and determine the polysaccharide content and nucleic acid content in the filtrate. The polysaccharide content is determined by the anthrone sulfuric acid method, and the nucleic acid content is determined by the phosphorus determination method. The method for preparing the biological sludge solution is as follows: place the activated sludge (taken from the cooling tower sedimentation tank of the LNG plant of Shaanxi Liquefied Natural Gas Investment Development Co., Ltd., China) on a centrifuge and centrifuge at 8000r / min for 10 minutes, discard the supernatant, and repeatedly centrifuge and wash with distilled water for 3 times to obtain a spare biological sludge, and mix the spare biological sludge with distilled water to obtain a biological sludge solution with a biological sludge concentration of 10g / L.

[0065] Experiment 1: 80 mg of Agent B of the circulating cooling water system fouling control agent was added to a conical flask containing 1 L of biological slime solution, and the mixture was circulated for 8 h. Then 0.5 mg of trichloroisocyanuric acid (Agent) was added and the mixture was circulated for 32 h. Samples were taken for analysis of the polysaccharide content and nucleic acid content. The results are shown in Table 1.

[0066] Experiment 2: 80 mg of Agent B of the circulating cooling water system fouling control agent was added to a conical flask containing 1 L of biological slime solution, and the mixture was circulated for 16 h. Then 1.0 mg of trichloroisocyanuric acid (Agent) was added and the mixture was circulated for another 24 h. Samples were taken for analysis of the polysaccharide content and nucleic acid content. The results are shown in Table 1.

[0067] Experiment 3: 80 mg of Agent B of the circulating cooling water system fouling control agent was added to a conical flask containing 1 L of biological slime solution, and the mixture was circulated for 24 h. Then 1.5 mg of trichloroisocyanuric acid (Agent) was added and the mixture was circulated for another 16 h. Samples were taken for analysis of the polysaccharide content and nucleic acid content. The results are shown in Table 1.

[0068] Experiment 4: 80 mg of Agent B of the circulating cooling water system fouling control agent was added to a conical flask containing 1 L of biological slime solution, and the mixture was circulated for 32 h. Then 1.5 mg of trichloroisocyanuric acid (Agent) was added and the mixture was circulated for another 8 h. Samples were taken for analysis of the polysaccharide content and nucleic acid content. The results are shown in Table 1.

[0069] Experiment 5: 80 mg of Agent B of the circulating cooling water system fouling control agent was added to a conical flask containing 1 L of biological slime solution, and the mixture was circulated for 16 h. Then 0.5 mg of trichloroisocyanuric acid (Agent) was added and the mixture was circulated for another 24 h. Samples were taken for analysis of the polysaccharide content and nucleic acid content. The results are shown in Table 1.

[0070] Experiment 6: 80 mg of Agent B of the circulating cooling water system fouling control agent was added to a conical flask containing 1 L of biological slime solution, and the mixture was circulated for 16 h. Then 1.5 mg of trichloroisocyanuric acid (Agent) was added and the mixture was circulated for another 24 h. Samples were taken for analysis of the polysaccharide content and nucleic acid content. The results are shown in Table 1.

[0071] Experiment 7: 80 mg of Agent B of the circulating cooling water system fouling control agent was added to a conical flask containing 1 L of biological slime solution, and the mixture was circulated for 24 h. Then 1.0 mg of trichloroisocyanuric acid (Agent) was added and the mixture was circulated for 16 h. Samples were taken for analysis of the polysaccharide content and nucleic acid content. The results are shown in Table 1.

[0072] Comparative experiment 1: 80 mg of agent B in the circulating cooling water system fouling control agent was added to a conical flask containing 1 L of biological slime solution, and the mixture was circulated for 40 hours. Samples were taken and analyzed for polysaccharide content and nucleic acid content. The results are shown in Table 1.

[0073] Comparative experiment 2: 1.5 mg of trichloroisocyanuric acid (agent A) was added to a conical flask containing 1 L of biological slime solution and rotated for 40 hours. Samples were taken and analyzed for polysaccharide content and nucleic acid content. The results are shown in Table 1.

[0074] Comparative experiment 3: 80 mg of agent B and 1.0 mg of trichloroisocyanuric acid (agent A) in the circulating cooling water system fouling control agent were added to a conical flask containing 1 L of biological sludge solution, and the mixture was circulated for 40 hours. Samples were taken for analysis of the polysaccharide content and nucleic acid content. The results are shown in Table 1.

[0075] Comparative experiment 4: 1.0 mg of trichloroisocyanuric acid (agent A) was added to a conical flask containing 1 L of biological slime solution, and the mixture was circulated for 16 h. Then 80 mg of agent B in the circulating cooling water system fouling control agent was added and the mixture was circulated for 24 h. Samples were taken and analyzed for polysaccharide content and nucleic acid content. The results are shown in Table 1.

[0076] Comparative experiment 5: 1.0 mg of trichloroisocyanuric acid (agent A) was added to a conical flask containing 1 L of biological sludge solution, and the mixture was circulated for 24 h. Then 80 mg of agent B in the circulating cooling water system fouling control agent was added and the mixture was circulated for 16 h. Samples were taken and analyzed for polysaccharide content and nucleic acid content. The results are shown in Table 1.

[0077] Table 1 Effect of fouling control agent in circulating cooling water system on removing biological slime in cooling water

[0078]

[0079] It can be seen from the results of the above examples and test examples that the circulating cooling water system fouling control agent and the use method thereof of the present invention have a good biological slime stripping effect.

[0080] Example 5

[0081] The circulating cooling water system fouling control agent and its use method of Experiment 6 and Comparative Experiment 1 and Comparative Experiment 2 in Example 4 were subjected to a sterilization efficiency evaluation test. In this example, the laboratory evaluation method of sterilization efficiency performance was carried out according to the "Static Sterilization Test of Heterotrophic Bacteria" in "Cooling Water Analysis and Test Methods" compiled by the Production Department and Development Department of China Petrochemical Corporation (published by the Information Center of Anqing Petrochemical General Plant in 1993). Take 4 500mL beakers and label them 1 to 3, take 300mL of the bacteria enriched in tap water respectively, add them into 500mL Erlenmeyer flasks, and operate No. 1, No. 2 and No. 3 respectively according to the experimental steps of Experiment 6 and Comparative Experiment 1 and Comparative Experiment 2 in Example 4, place them in a shaking table at 32±2°C, and the speed of the shaking table is 180rpm. Samples are taken at different times (2h, 8h, 16h, 24h, 32h and 40h) to monitor the number of heterotrophic bacteria in the water (the starting time is calculated from the first addition of the drug, the same below), and blank samples are made at the same time to calculate the sterilization rate. The results are shown in Figure 3 The experimental results show that the circulating cooling water system fouling control agent and the use method thereof of the present invention have good bactericidal effects.

[0082] The fouling control agent of the present invention can not only more thoroughly remove the biological slime deposited on the inner wall of the equipment and pipeline of the circulating cooling water system, but also kill the microorganisms and algae in the circulating water. It has the characteristics of small dosage and microorganisms are not easy to develop drug resistance. By adding the fouling control agent of the circulating cooling water system, the control standard of the microorganisms in the circulating water system can reach the "Industrial Circulating Cooling Water Treatment Design Code" (GB50050-1995).

Claims

1. A fouling control agent for a circulating cooling water system, characterized in that: It comprises agent A and agent B; the agent A is trichloroisocyanuric acid, and the agent B is composed of the following raw material components by mass percentage: 20-30% of chlorhexidine, 10-20% of isothiazolinone, 5-15% of alkyl epoxycarboxylate, and the rest is deionized water, and the sum of the mass percentages of the above components is 100%.

2. The fouling control agent for a circulating cooling water system according to claim 1, characterized in that: The dosage of the agent A in the circulating cooling water system is 0.5-5.0 mg / L; the dosage of the agent B in the circulating cooling water system is 10-150 mg / L.

3. The fouling control agent for a circulating cooling water system according to claim 1, characterized in that: The alkyl epoxy carboxylate is any one of alkyl decacyclic epoxy carboxylate, alkyl dodecacyclic epoxy carboxylate, alkyl pentacyclic epoxy carboxylate and alkyl eicocyclic epoxy carboxylate.

4. The fouling control agent for a circulating cooling water system according to claim 1, characterized in that: The preparation method of the B agent is: Step 1: Mix deionized water and alkyl epoxy carboxylate, stir for 5-10 minutes at a stirring rate of 250-300 r / min to obtain an alkyl epoxy carboxylate solution; Step 2: Add benzyl alcohol to the alkyl epoxy carboxylate solution obtained in step 1, stir for 20-30 minutes at room temperature at a stirring rate of 250-300 r / min to obtain a mixed solution; Step 3: Add isothiazolinone and deionized water to the mixed solution obtained in step 2, stir for 10-15 minutes at room temperature, and stir at a rate of 150-200 r / min to obtain a mixed agent; Step 4: Add the mixed reagent obtained in step 3 into a centrifugal filter and filter for 10-15 minutes. After filtration, take the supernatant and package it with a packaging machine to obtain agent B in the circulating cooling water system fouling control agent.

5. The fouling control agent for a circulating cooling water system according to claim 1, characterized in that: The preparation method of the alkyl epoxy carboxylate is specifically as follows: Dissolve fatty alcohol polyoxyethylene ether and sodium chloroacetate in anhydrous ethanol at a molar ratio of 1:1.0-1.5, stir to fully dissolve, then keep the reaction solution at 45-50°C and stir for 30 minutes, and slowly add sodium hydroxide in batches within 0.5-1.0 hours, and finally control the reaction temperature at 50-55°C, react for 3-4 hours, then increase the temperature to 55-60°C, react for 0.5-1.0 hours, and then use anhydrous ethanol as a diluent, cool the reaction mixture in ice water, filter, and distill to obtain alkyl epoxy carboxylate.

6. The fouling control agent for a circulating cooling water system according to claim 5, characterized in that: The molar ratio of the fatty alcohol polyoxyethylene ether, sodium chloroacetate and sodium hydroxide is 1:1.0-1.5:1.0-1.

3.

7. The method for using the fouling control agent for a circulating cooling water system according to any one of claims 1 to 6, characterized in that: Specifically: add agent B and agent A to the circulating cooling water system in sequence, the time interval between adding agent B and agent A is 5-48h, and the operating time after adding agent B is 8-40h.

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