Fouling control agent for circulating cooling water system and method of use

Abstract

The present invention discloses a fouling control agent for a circulating cooling water system, including 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 benzyl alcohol, 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%. The present invention also discloses a method for using the fouling control agent, 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 5-48h, and the operating time after adding agent B is 8-40h. The circulating cooling water system fouling control agent has good bactericidal properties and good decomposition and stripping effect on biological slime. It can be used to quickly remove biological slime from the circulating cooling water system while also cleaning dirt on metal surfaces 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 circulates and concentrates in the system for a long time, causing the nutrients needed for microbial growth to accumulate in the water, making it easy for microorganisms to multiply in large numbers. At the same time, this large-scale microbial growth also produces a large amount of biological slime in the circulating water system. Biological slime not only sharply deteriorates the cooling water quality, but also easily deposits in cooling towers and heat exchange equipment, isolating the protective effect of the chemicals on the metal, preventing the chemicals from exerting their due corrosion and scale inhibition efficiency. It can also cause corrosion of metal equipment in the cooling water system and, in severe cases, block pipes, causing great harm to industrial production. To avoid this kind of situation, the most effective way is to add fungicides to the control system to inhibit the growth of microorganisms.

[0003] Commonly used fungicides are divided into two categories: oxidizing and non-oxidizing fungicides. Currently, oxidizing fungicides are mostly chlorine-containing fungicides, such as sodium hypochlorite, chlorine dioxide, and chlorine gas. However, these fungicides are associated with high risk, poor efficacy in alkaline environments, and a high risk of developing drug resistance. Trichloroisocyanuric acid, as a new generation of low-toxic, broad-spectrum, and highly effective fungicide, can effectively kill microorganisms over the long term. It also avoids the transportation safety hazards and leakage risks associated with using liquid chlorine, as well as the unstable bactericidal effect that can result from pH fluctuations during the sterilization process. Furthermore, its bactericidal effect fully meets the requirements for various microbial control indicators in circulating cooling water systems. However, non-oxidizing fungicides have disadvantages such as large single-component dosages, a single bactericidal species, poor killing efficacy, and a high risk of developing drug resistance. Synergistic compound formulations, on the other hand, have a synergistic effect relative to their individual components, 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 containing tribenzylphenylphosphonium chloride, dithiocyanomethane and copper sulfate. Although phosphorus-containing cations replace nitrogen-containing cations in quaternary ammonium salts, and structural analysis shows that the bactericidal effect of quaternary phosphonium salts is better than that of quaternary ammonium salts, the introduction of phosphorus and sulfur elements in the fungicide will further increase eutrophication of water bodies, and the indirect generation of H2S will aggravate the damage of 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 quaternary ammonium salt selected for use cannot be shared with chlorophenol biocides, and should not be shared with anionic surfactants. When Ca, Mg and Fe metal ions are present in a large amount in the circulating water, the bactericidal effect of the quaternary ammonium salt can be reduced, and the quaternary ammonium salt is prone to foaming and needs to be used together with a defoamer, which is unfavorable for industrial production and easily causes environmental pollution.

[0005] Although a wide variety of slime stripping agents are currently available, their performance and environmental benefits still fall short of current water treatment requirements. Foreign research on slime stripping agents has primarily focused on developing environmentally friendly, biodegradable, and low-cost water treatment agents. Domestic slime stripping agents for circulating water are mostly cationic surfactants. While they offer good stripping performance, they also have several drawbacks. A Chinese patent (Application Number: 200510025391.3, Publication Number: CN1853473A, Publication Date: April 25, 2005) discloses a fungicide and algaecide effective for microbial slime stripping. The agent contains isothiazolinone, dodecyldimethylbenzyl ammonium chloride, and polyacrylic acid. However, bactericides and algaecides are generally used in high doses 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, tris(hydroxymethylnitromethane) and dibromoethanol. Its disadvantage is that tris(hydroxymethylnitromethane) slowly decomposes and releases formaldehyde in a slightly alkaline solution, shortening its service life. Therefore, it is not suitable for use in slightly alkaline circulating cooling water.

[0006] In order to kill microorganisms and remove biological slime in circulating cooling water systems, existing bactericides or slime strippers need to be synthesized or compounded with a large amount of chlorine, phosphorus and sulfur-containing chemicals. This not only aggravates the eutrophication of water bodies and the corrosion of metal equipment, but also causes serious pollution to the environment and makes the discharged wastewater difficult to treat. Therefore, there is an urgent need to develop a circulating cooling water system fouling control agent that can efficiently and safely strip biological slime from 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 solution adopted by the present invention is a fouling control agent for a circulating cooling water system, comprising an agent A and an agent B; agent A is trichloroisocyanuric acid, and agent B is composed of the following raw material components by mass percentage: 20-30% of benzyl alcohol, 10-20% of isothiazolinone, 5-15% of alkyl epoxy carboxylate, and the remainder 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 eicocyclyloxy carboxylate.

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

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

[0015] Step 2: adding benzyl alcohol to the alkyl epoxy carboxylate solution obtained in step 1, stirring at room temperature for 20-30 minutes 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, and stir at room temperature for 10-15 minutes at a stirring rate of 150-200 r / min to obtain a mixed agent;

[0017] Step 4: Add the mixed reagent obtained in step 3 to 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 maintain the reaction solution at 45-50°C and stir for 30 minutes, while slowly adding sodium hydroxide in batches within 0.5-1.0 hours, 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, with the time interval between adding agent B and agent A being 5-48 hours, and the operating time after adding agent B being 8-40 hours.

[0022] The beneficial effects of the present invention are as follows: the high-efficiency, fast, phosphorus-free, low-chlorine circulating cooling water system fouling control agent of the present invention is composed of low-chlorine oxidizing trichloroisocyanuric acid (Agent A) and a 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 risk, poor effect in alkaline environments, and easy development of drug resistance; Agent B solves the problem that compounded non-oxidizing bactericides are not suitable for use with anionic surfactants and reduce the bactericidal effect of quaternary ammonium salts. In addition, the method for 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 achieve the dual functions of stripping and sterilization, and the problem that the continuous dosing method requires a large amount of agent and is prone to microbial resistance. This 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 circulating cooling water systems, while also cleaning dirt on metal surfaces and improving the heat exchange rate of equipment. It is suitable for water circulation systems with local high temperatures, such as industrial circulating water systems, urban geothermal heating systems, pipelines, and oil well production equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The 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 circulating cooling water system fouling control agent for 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 will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0027] The present invention provides a fouling control agent for a circulating cooling water system, comprising an agent A and an agent B, each stored separately. Agent A comprises trichloroisocyanuric acid, and its usage in the circulating water system is 0.5 to 5.0 mg / L, preferably 0.5 to 2.0 mg / L. Agent B comprises the following raw material components by mass: 20-30% benzyl salicylate, 10-20% isothiazolinone, 5-15% alkyl epoxy carboxylate, and the remainder deionized water, the sum of the mass percentages of the aforementioned components being 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, stir and dissolve, and slowly add sodium hydroxide in batches within 0.5-1.0 hours. 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 to synthesize AEC crude product, 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 for a 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, and stir at room temperature for 5-10 minutes at a stirring 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: adding benzyl alcohol to the alkyl epoxy carboxylate solution obtained in step 1, stirring at room temperature for 20-30 minutes 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, and stir at room temperature for 10-15 minutes at a stirring rate of 150-200 r / min to obtain a mixed agent;

[0037] Step 4: Add the mixed reagent obtained in step 3 to 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: Primarily composed of 5-chloro-2-methyl-4-isothiazolin-3-one and 2-methyl-4-isothiazolin-3-one, it kills bacteria by breaking the bonds between bacterial and algal proteins. It has a strong inhibitory and killing effect on common bacteria, fungi, and algae. It has high biocidal 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 nonionic surfactants. At high doses, isothiazolinone has a significant effect on removing biological slime.

[0042] Alkyl epoxy carboxylates: Phosphorus-free, nonionic surfactants that are non-toxic, chlorine-resistant, temperature-resistant, and possess excellent scale inhibition, slow-release, and bactericidal properties. They exhibit excellent thermal stability and scale inhibition in cooling water systems with high pH, ​​high alkalinity, high hardness, and high concentration ratios, effectively cleaning metal surface dirt and improving equipment heat exchange efficiency.

[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 remover; 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 sequentially adding Agent B and Agent A in the present method) to continuously remove biological slime and microorganisms from the circulating cooling water system. Studies have found that controlling the timing of adding Agent A and Agent B within the preferred range above can achieve better removal results.

[0047] The method of the present invention first adds Agent B, a non-oxidizing circulating cooling water system fouling control agent with a biosludge stripping effect, to the circulating cooling water. Then, an oxidizing biocide (Agent A) with bactericidal or bacteriostatic properties is added. Because the oxidizing biocide rapidly kills bacteria, it more easily kills free bacteria stripped by the non-oxidizing biocide, thereby reducing the accumulation of sludge on the inner walls of equipment and pipes in 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, controlling the water bath temperature at 50 ° C, and heating for 0.5 h to completely dissolve the fatty alcohol polyoxyethylene ether;

[0051] Step 2: The reaction molar ratio of the fatty alcohol polyoxyethylene ether to sodium chloroacetate was controlled at 1:1.0, and sodium chloroacetate powder was evenly added to the homogeneous fatty alcohol polyoxyethylene ether solution obtained above. The reaction molar ratio of the fatty alcohol polyoxyethylene ether to sodium hydroxide was controlled at 1:1.0, and sodium hydroxide powder was evenly added to the homogeneous reaction solution obtained above. The water bath temperature was 50°C and the heating time was 1.0 hour. The fatty alcohol polyoxyethylene ether and sodium chloroacetate were fully reacted by the strong base sodium hydroxide to activate the hydroxyl (-OH) groups to form alkyl decacyclic carboxylate (AEC-10). The mixture was allowed to stand at -4°C for 24 hours and purified to obtain the crude AEC-10 product. The crude AEC-10 product was reacted with anhydrous ethanol at a molar ratio of 1:1.0, the water bath temperature was 45°C, and the heating time was 1.0 hour. After the experiment, the reaction mixture was cooled in an ice-water bath and allowed to stand for 24-36 hours. It was then filtered and distilled to 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 was 85.2%, the product purity was >90%, and it was an orange-yellow viscous liquid; the synthetic conversion yield of AEC-12 was 84.5%, the product purity was >85%, and it was an orange-yellow viscous liquid; the synthetic conversion yield of AEC-15 was 83.6%, the product purity was >85%, and it was an orange-red viscous liquid; the synthetic conversion yield of AEC-20 was 83.1%, the product purity was >85%, and it was 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 are at 3150cm -1 、2855~2822cm -1 The stretching vibration peak of CH appears, 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 an in-plane deformation vibration peak of the carboxyl group, 1650 cm -1 and 1560cm -1 The carbonyl coupling effect and the carbon-oxygen double bond stretching vibration peaks of -COOH appeared, indicating that the AEC-n synthetic precursor, fatty alcohol polyoxyethylene ether, underwent a carboxymethylation reaction with sodium chloroacetate, which showed the absorption vibration peak of the carboxylate. Based on the appearance of the functional group peaks in the above AEC-n products, the accuracy of the AEC-n compound synthesized in the experiment was verified.

[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, and 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 after the raw materials are added, add deionized water to a quantitative amount, 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 to 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 rotating coupon method according to the method of "Determination of Corrosion Inhibition Performance of Water Treatment Agents" in GB / T 18175-2000. The experimental water sample was prepared with anhydrous calcium chloride, magnesium sulfate heptahydrate, sodium chloride and sodium bicarbonate in a 250mL volumetric flask. The [Ca 2+ ]=265mg / L, [Mg 2+ ]=47mg / L, [HCO3 -)]=122mg / L, A20 carbon steel specimens need to be pretreated before the experiment. The carbon steel is first wiped clean with sandpaper, then scrubbed with n-hexane and anhydrous ethanol in turn to remove oil stains on the surface of the steel sheet, and then dried for use. Take 11 carbon steel coupons prepared in advance for the A20 standard test 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 was added to beaker No. 1 as a blank control group, and 500mL of experimental water sample was first added to beakers No. 2 to 8, and then the concentrations of agent B were 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. The corrosion inhibition efficiency of agent B was determined using an RCC-Ⅲ rotating coupon corrosion monitor with a rotation rate of 60r / min and a water sample test temperature of 32°C. The reaction time was 24h. After the experiment, the corrosion inhibition efficiency of agent B on carbon steel sheets was calculated using the coupon mass loss method. The results of the determination are as follows: Figure 2 As shown in the figure, the corrosion inhibition rate gradually increases with the increase of the concentration of agent B. 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 for the bioslime stripping performance adopts the extracellular polymer method (i.e., the stripping performance of the bioslime 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 properties of bacterial flocs and the physical properties of granular sludge, promote intercellular cohesion and structural stability. When the bioslime stripping agent acts on the activated sludge, the extracellular polymers are destroyed, and organic components such as polysaccharides and nucleic acids are dispersed in the circulating cooling water, thereby achieving the stripping of the bioslime. Therefore, the stripping effect of the slime stripping agent can be evaluated based on 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 bioslime stripping performance of the agent. In the embodiment, the rotation is operated using a rotator (HZ-2010 rotary constant temperature speed regulating bottle shaking cabinet, Changzhou Kaihang Instrument Co., Ltd.), and the rotation speed is controlled to be 180 r / min and the temperature is 32±2°C.

[0064] The method for sampling and analyzing polysaccharide and other content is as follows: the mixed liquid is filtered and the polysaccharide and nucleic acid contents in the filtrate are determined. The polysaccharide content is determined using the anthrone-sulfuric acid method, and the nucleic acid content is determined using the phosphorus determination method. The method for preparing the biosludge solution is as follows: activated sludge (obtained from the cooling tower sedimentation tank of the LNG plant of Shaanxi Liquefied Natural Gas Investment and Development Co., Ltd., China) is placed in a centrifuge and centrifuged at 8000 rpm for 10 minutes. The supernatant is discarded and the solution is repeatedly centrifuged and washed with distilled water three times to obtain a reserve biosludge. The reserve biosludge is then mixed with distilled water to obtain a biosludge solution with a biosludge concentration of 10 g / 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 spun for 8 hours. Then, 0.5 mg of trichloroisocyanuric acid (Agent A) was added and spun for another 32 hours. Samples were taken and analyzed for polysaccharide 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 spun for 16 hours. Then, 1.0 mg of trichloroisocyanuric acid (Agent A) was added and spun for another 24 hours. Samples were taken and analyzed for polysaccharide 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 spun for 24 hours. Then, 1.5 mg of trichloroisocyanuric acid (Agent A) was added and spun for another 16 hours. Samples were taken and analyzed for polysaccharide 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 spun for 32 hours. Then, 1.5 mg of trichloroisocyanuric acid (Agent A) was added and spun for another 8 hours. Samples were taken and analyzed for polysaccharide 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 spun for 16 hours. Then, 0.5 mg of trichloroisocyanuric acid (Agent A) was added and spun for another 24 hours. Samples were taken and analyzed for polysaccharide 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 spun for 16 hours. Then, 1.5 mg of trichloroisocyanuric acid (Agent A) was added and spun for another 24 hours. Samples were taken and analyzed for polysaccharide 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 spun for 24 hours. Then, 1.0 mg of trichloroisocyanuric acid (Agent A) was added and spun for another 16 hours. Samples were taken and analyzed for polysaccharide and nucleic acid content. The results are shown in Table 1.

[0072] Comparative 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. The solution was circulated for 40 hours, and samples were taken for analysis of polysaccharide and nucleic acid contents. 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 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) in the circulating cooling water system fouling control agent were added to a conical flask containing 1 L of biological slime solution. The solution was rotated for 40 hours, and samples were taken for analysis of polysaccharide 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 spun for 16 h. Then, 80 mg of Agent B from the circulating cooling water system fouling control agent was added and spun for a further 24 h. Samples were taken and analyzed for polysaccharide 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 slime solution and spun for 24 h. Then, 80 mg of Agent B from the circulating cooling water system fouling control agent was added and spun for another 16 h. Samples were taken and analyzed for polysaccharide and nucleic acid content. The results are shown in Table 1.

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

[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 agents and their methods of use from Experiment 6 and Comparative Experiments 1 and 2 in Example 4 were subjected to sterilization efficiency evaluation tests. In this example, the laboratory sterilization efficiency evaluation method was conducted in accordance with the "Static Sterilization Test for Heterotrophic Bacteria" in "Cooling Water Analysis and Test Methods," compiled by the Production and Development Departments of China Petrochemical Corporation (published by the Information Center of Anqing Petrochemical General Plant in 1993). Take 4 500mL beakers and mark them as 1 to 3, take 300mL of the bacteria enriched in tap water respectively, add them to 500mL Erlenmeyer flasks, and operate No. 1, No. 2 and No. 3 according to the experimental steps of Experiment 6 and Comparative Experiment 1 and Comparative Experiment 2 in Example 4, respectively. Place them in a shaker at 32±2°C, and the shaker speed 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 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 the table. 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 biological slime deposited on the inner walls of equipment and pipes in a circulating cooling water system, but also simultaneously kill microorganisms and algae in the circulating water. It has the characteristics of low dosage and low resistance of microorganisms. By adding the fouling control agent for the circulating cooling water system, the control standard of microorganisms in the circulating water system can meet 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: The invention comprises an agent A and an 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 benzyl alcohol, 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%; The dosage of the agent A in the circulating cooling water system is 0.5-2.0 mg / L; the dosage of the agent B in the circulating cooling water system is 10-150 mg / L; The alkyl epoxy carboxylate is any one of alkyl pentadecyl epoxy carboxylate and alkyl eicosyl epoxy carboxylate; The preparation method of the B agent is: Step 1: Mix deionized water and alkyl epoxy carboxylate, and stir for 5-10 minutes at a stirring rate of 250-300 r / min to obtain an alkyl epoxy carboxylate solution; The preparation method of the alkyl epoxy carboxylate is specifically as follows: Dissolving fatty alcohol polyoxyethylene ether and sodium chloroacetate in anhydrous ethanol at a molar ratio of 1:1.0-1.5, stirring to fully dissolve, then maintaining the reaction solution at 45-50° C. and stirring for 30 minutes, while slowly adding sodium hydroxide in batches over 0.5-1.0 hours, with the molar ratio of fatty alcohol polyoxyethylene ether, sodium chloroacetate, and sodium hydroxide being 1:1.0-1.5:1.0-1.3; finally, controlling the reaction temperature at 50-55° C., reacting for 3-4 hours, then raising the temperature to 55-60° C., reacting for 0.5-1.0 hours, and then using anhydrous ethanol as a diluent, cooling the reaction mixture in ice water, filtering, and distilling to obtain an alkyl epoxy carboxylate; Step 2: adding benzyl alcohol to the alkyl epoxy carboxylate solution obtained in step 1, stirring at room temperature for 20-30 minutes 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, and stir at room temperature for 10-15 minutes at a stirring rate of 150-200 r / min to obtain a mixed agent; Step 4: Add the mixed reagent obtained in step 3 to 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.

2. The method for using the fouling control agent for a circulating cooling water system according to claim 1, wherein: 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 8-48 hours, and the operating time after adding agent B is 8-40 hours.

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