CN101182643A - A kind of environment-friendly composite pre-film agent for pre-film treatment of circulating cooling water system and its application method - Google Patents

Abstract

The invention belongs to the technical field of circulating cooling water treatment, and specifically relates to an environment-friendly composite pre-film agent for pre-film treatment of a circulating cooling water system and a method for using the environment-friendly composite pre-film agent based on 2-phosphonic acid- 1,2,4-Butane tricarboxylate and sodium polyepoxysuccinate are the main ingredients, and an appropriate amount of carboxylic acid-based copolymer, benzotriazole, sodium molybdate, zinc sulfate and other ingredients are added. When the composite pre-film agent is directly added to the circulating cooling water, a protective film with anti-corrosion function can be formed on the surface of carbon steel after 48 hours of operation. The corrosion resistance of the formed film to copper sulfate standard drip solution is far superior to that of traditional Phosphate-zinc pre-film agent. The environmental-friendly composite pre-film agent has a total phosphorus content of less than 7.5mg/L during pre-filming, and does not need to adjust the pH of the water. After pre-filming, the water quality is clear and transparent, and it can be directly converted to normal operation without replacing the water quality. Moreover, it reduces the basic chemical dosing cost during normal operation after the water quality is replaced, and at the same time, there is no discharge of pre-membrane waste liquid, which belongs to an environmentally friendly pre-membrane method.

Description

A kind of environment-friendly composite pre-film agent for pre-film treatment of circulating cooling water system and its application method

technical field

The invention belongs to the technical field of circulating cooling water treatment, and relates to an environment-friendly composite pre-filming agent used for pre-filming treatment of circulating cooling water system and its use method, in particular to a compound pre-filming agent for no acid addition, no pre-filming after pre-filming The replacement water quality can be directly converted into an environment-friendly composite pre-film agent for a circulating cooling water system in normal operation and its usage method.

Background technique

Pre-film is one of the essential and important links in industrial water treatment technology, and an important means to improve the corrosion resistance of circulating water equipment. Its purpose is to form a dense and corrosion-resistant protection layer on the metal surface after chemical cleaning. membrane. For the same circulating cooling water treatment formula, whether it is pre-coated or not directly affects the corrosion inhibition effect of the formula, and the corrosion rate is about 20 times worse. In order to improve the corrosion inhibition effect of the formula, the new circulating cooling water system must be cleaned before pre-coating treatment before starting up, and the old system must also be pre-coated after overhaul and pickling.

The pre-filming agent of the circulating cooling water system is often composed of corrosion inhibitors and appropriate scale inhibitors and dispersants. The use of corrosion inhibitors for circulating cooling water treatment began with the use of sodium tripolyphosphate in the 1920s, and began to develop in the 1940s. So far, after more than 70 years of development, it has experienced: chromate (1940s to 1950s) - polyphosphate (1960s) - organic phosphonate (1970s) - low phosphorus retardation Corrosion agent organic phosphine carboxylic acid (1980s) - non-phosphorus corrosion inhibitor (1980s) and other stages of use. Although chromate has good corrosion inhibition effect, it is gradually replaced by polyphosphate due to its toxicity. Polyphosphate, such as sodium tripolyphosphate and sodium hexametaphosphate, is a typical type of cathodic corrosion inhibitor. Ion action forms a deposition protective film, which has a good corrosion inhibition effect, but due to its unstable structure, orthophosphate is easily hydrolyzed, resulting in the formation of phosphate scale; in addition, phosphate discharge into water can cause environmental eutrophication pollution. In the 1970s, organic phosphonic acid corrosion inhibitors appeared, such as hydroxyethylene diphosphonic acid (HEDP), amino trimethylene phosphonic acid (ATMP), ethylenediamine tetramethylene phosphonic acid (EDTMP) , diethylenetriaminepentamethylenephosphonic acid (DETPMP), etc. These organic phosphonates have a stable structure and lower phosphorus content than polyphosphates, reducing the risk of calcium phosphate scale formation and environmental eutrophication pollution pressure, and thus developed rapidly. Due to environmental protection restrictions on phosphorus emissions, organic phosphonic acid corrosion inhibitors with lower phosphorus content appeared in the 1980s, such as 2-phosphonic acid-1,2,4-tricarboxylic acid (PBTCA), 2-hydroxy Phosphonoacetic acid (HPAA). During this period, non-phosphorus corrosion inhibitors such as silicate, molybdate, and tungstate also began to be tried. Silicate is cheap and non-toxic, but if it is not well controlled, it will form silicon scale that is difficult to clean; and molybdate and Although tungstates are non-toxic, their promotion is limited due to their high price and large dosage. Phosphorus-containing corrosion _and scale inhibitors range _from polyphosphate, organic phosphonate to organic phosphine _carboxylic acid. Methylphosphonic acid (ATMP) is 31.1% (calculated as P), hydroxyethylene diphosphonic acid (HEDP) is 30.1% (calculated as P), ethylenediaminetetramethylenephosphonic acid (EDTMP) is 28.4% (calculated by P), 27.1% (calculated by P) of diethylenetriaminepentamethylenephosphonic acid (DEPTMP), 19.9% (calculated by P) of 2-hydroxyphosphinoacetic acid (HPA), 2-phosphono-1,2,4-tricarboxylic acid (PBTCA) is 11.9% (calculated as P), and the gradual reduction of phosphorus content reflects the improvement of human environmental protection awareness.

In circulating water treatment technology, due to the early use of corrosion inhibitors, the corrosion problem of equipment has been alleviated to a certain extent, and the scaling problem has become more prominent, forcing people to devote themselves to solving the scaling problem. The use of scale inhibitors and dispersants for circulating cooling water treatment is later than that of corrosion inhibitors. It started to use sodium lignosulfonate in the 1960s, and its development has experienced natural scale inhibitors and dispersants (initial stage in the 1960s)—— Polycarboxylates (1970s) - binary and tricarboxylic acid copolymers - multifunctional copolymers (1980s) - low-phosphorus new organic polymers (1990s) - Phosphorus-free biodegradable polymers (late 1990s to early 2000s). Although natural scale inhibitors such as sodium lignosulfonate and sodium humate are environmentally friendly and have a certain scale inhibition effect, they can partially solve the problems of scale deposition and zinc salt stability, but they are far from meeting the scale inhibition performance of the circulating cooling water system. Require. The development of polymer scale inhibitors and dispersants has developed from polycarboxylic acids, dibasic and tribasic carboxylic acid copolymers to multifunctional copolymers, which has made breakthroughs in water treatment technology. Because they are phosphorus-free, they were once considered to be Non-toxic, less polluting and environmentally acceptable water treatment chemicals, but the potential harm caused by their long-term accumulation in the environment is ignored. Because studies in recent years have shown that although most carboxylic acid polymers and copolymers have low toxicity, they generally cannot be decomposed into simple non-toxic substances under the action of microorganisms and fungi, that is, they cannot be biodegraded or can only be destroyed in a small amount. Biodegradation, if enriched in water for a long time, will also pollute the environment, especially in some areas with strict environmental protection requirements such as offshore oil fields. Therefore, in the 1990s, several well-known water treatment companies in the United States, Japan, Germany, etc. began to work on finding an alternative to polycarboxylic acid, which has excellent scale and corrosion inhibition properties and can be biologically Degradable "green" water treatment chemicals. The development of phosphorus-free, biodegradable green corrosion and scale inhibitors polyaspartic acid and polyoxysuccinic acid indicates that green scale inhibitors have become the development direction of water treatment chemicals.

In the existing pre-film technology, the traditional pre-film agent is often used, that is, the phosphorus-zinc pre-film agent. It is a solid pre-film agent with polyphosphate and zinc salt as the main components. It usually consists of 65% to 70% Sodium hexametaphosphate is mixed with 30% to 35% zinc sulfate heptahydrate, the concentration used is 200 to 250 mg·L ^-1 , and the pH needs to be controlled at 5.5 to 6.5. The pre-filming agent is easy to hydrolyze and form calcium phosphate precipitation during operation. Usually, after 24 hours of pre-filming, 30-100 mg·L ^-1 polymer dispersant (usually polycarboxylate or Polycarboxylate copolymer) to prevent the deposition of calcium phosphate scale and zinc salts. Although the effect of this pre-film agent is good, there are many disadvantages: (1) polyphosphate is very easy to decompose in water, forming calcium phosphate precipitation; There are often many insoluble substances added to the system, and the turbidity of the water is relatively high (>20mg·L ^-1 ); (3) The pre-film conditions (temperature, pH) are relatively harsh, and a large amount of sulfamic acid or Sulfuric acid adjusts the pH; (4) the amount of pre-film agent is large, and the pre-film effect is unstable; (5) after the pre-film is completed, it is necessary to adopt a large discharge (discharge of the pre-film liquid) and a large supplement (supplement of fresh water) to convert To normal operation, the replacement time is long, and the water consumption is relatively large; (6) high-phosphorus formula, phosphorus is used as a nutrient source, which makes the water body eutrophic and destroys the ecological balance; (7) operation and management are cumbersome. Therefore, seeking a new environmentally friendly pre-film agent that does not adjust the pH, has a good pre-film effect, is convenient for operation and management, can be directly transferred to normal operation without replacement after pre-film, and is pollution-free is the solution to the problem of the traditional pre-film solution for the circulating cooling water system. An effective approach to the drawbacks of film agents.

Chinese Patent Application Publication No. CN1715447A discloses a pre-film agent for circulating cooling water system, which consists of 40-60% sodium hexametaphosphate, 10-15% zinc sulfate, and 5-11% sodium tripolyphosphate. , 4-8% of aminotrimethylene phosphonic acid, 3-6% of acrylic acid-acrylic acid ester copolymer, and the rest of water. Compared with the traditional pre-filming agent, this formula adds organic phosphonate (aminotrimethylene phosphonic acid) and carboxylic acid copolymer (acrylic acid-acrylate copolymer) in addition to polyphosphate and zinc sulfate, which improves the pre-filming agent. The use effect of the film is also relatively loose. However, the formula is still a high-phosphorus formula, and after pre-filming, it still needs to replace the water quality and turn it into normal operation. Since the replaced pre-membrane sewage contains high phosphorus, it will pollute the environment if it is discharged into the water body.

Chinese patent ZL02158580.6 provides a pre-coating agent for circulating cooling water systems without pH adjustment, which consists of 2-10% phosphoric acid, 1-10% zinc dihydrogen phosphate, and 5-18% organic phosphine Acid, 4.5-10.5% of copolymer containing carboxylic acid groups, 0.5-2.0% of benzotriazole and the rest of water. Compared with the traditional pre-filming agent, this formula uses organic phosphonic acid instead of part of inorganic phosphoric acid, which reduces the phosphorus content; and it does not need to adjust pH when using, it is convenient to add medicine, and the turbidity is small, but the formula still contains relatively High phosphorus, and after the pre-membrane is completed, the water quality still needs to be replaced to return to normal operation. Since the replaced pre-film sewage contains high phosphorus, it will still pollute the environment if it is discharged into the water body.

In order to achieve the purpose of environmental protection, the present invention adopts organic phosphine corrosion inhibitor 2-phosphonic acid group-1,2,4-tricarboxylic acid (PBTCA) with the lowest phosphorus content and phosphorus-free, biodegradable polyepoxysuccinic acid (PESA) As the main component of the pre-film agent, PESA not only has the function of scale inhibition and dispersion, but also can form an anti-corrosion protective film on the surface of carbon steel. At present, there is no report on the pre-film agent mainly composed of 2-phosphono-1,2,4-tricarboxylic acid (PBTCA) and polyepoxysuccinic acid (PESA).

Contents of the invention

One of the objectives of the present invention is to provide a low-phosphorus environmental-friendly composite pre-film agent for pre-film treatment of circulating cooling water, so as to overcome the high phosphorus content of the existing pre-film agent formula and easily cause eutrophication of water bodies The problem.

The second object of the present invention is to provide a method for using an environment-friendly composite pre-film agent. After using this environment-friendly composite pre-film agent, there is no need to replace the water quality, and the pre-film treatment formula can be directly transferred to normal operation. A large amount of water is replaced, and because there is no discharge of pre-membrane waste liquid, the pollution to the environment is reduced.

In order to achieve the above object, the low-phosphorous environment-friendly composite pre-film agent proposed by the present invention, the composite pre-film agent consists of 2-phosphonic acid group-1,2,4-tricarboxylic acid butane (PBTCA), polyepoxysuccinic acid Sodium is the main component (PESA), and an appropriate amount of carboxylic acid-based copolymer, sodium molybdate (Na ₂ MoO ₄ ), benzotriazole, zinc sulfate (ZnSO ₄ ) and water are added, and the weight percentage of its components as follows:

PBTCA 12%～18%

PESA 6%～15%

Carboxylic acid-based copolymer 0.3%～2%

Benzotriazole 0.5%～2%

_{Na2MoO4 0.5} %～2%

_ZnSO4 2%～5%

The rest is water, and its total weight satisfies 100%.

In the present invention, the 2-phosphono-1,2,4-tricarboxylic butane (PBTCA) is a commercially available liquid preparation with an effective concentration of 50%.

In the present invention, the sodium polyepoxysuccinate is a commercially available liquid preparation with a solid content of 40%, and its structural formula is:

Wherein, the degree of polymerization n is an integer in the range of 4-50, preferably in the range of 4-25.

In the present invention, the carboxylic acid-based copolymer is acrylic acid/2-methyl-2'-acrylamido propane sulfonic acid binary copolymer (AA/AMPS) or acrylic acid/2-methyl-2'- Acrylamidopropanesulfonic acid/hydroxypropyl acrylate terpolymer (AA/AMPS/HPA), is a commercially available liquid formulation with a solids content of 30%.

In the present invention, the benzotriazole is a commercially available solid preparation.

In the present invention, the sodium molybdate is a commercially available solid preparation sodium molybdate dihydrate (Na ₂ MoO ₄ ·2H ₂ O).

In the present invention, the zinc sulfate is commercially available zinc sulfate heptahydrate (ZnSO ₄ ·7H ₂ O).

The composite pre-film agent in the present invention is composed of six components such as PBTCA, sodium polyepoxysuccinate, carboxylic acid-based copolymer, benzotriazole, sodium molybdate, and zinc sulfate. Because PBTCA and carboxylic acid-based copolymers in these six components are acidic products, sodium polyepoxysuccinate and sodium molybdate are alkaline sodium salts, and polyepoxysuccinic acid is greatly reduced due to solubility under acidic conditions. Deposits will occur at high concentrations; imidazoline corrosion inhibitors have very low solubility (<1%) or even insoluble in acidic environments, but are soluble in water in alkaline environments; zinc salts are soluble in acidic water solvents , but will be deposited in an alkaline environment. Therefore, the preparation method of the composite prefilming agent of the present invention is as follows: mix PBTCA, carboxylic acid-based copolymer with water and stir evenly, then add zinc sulfate heptahydrate and stir to dissolve, to obtain agent A, for subsequent use; Mix sodium molybdate with water and stir evenly, then add benzotriazole and sodium molybdate, stir and dissolve, and obtain agent B for later use.

When the environment-friendly composite pre-film agent of the present invention is used, it is only necessary to directly add agent A and agent B into the circulating cooling water when adding, and the addition amount is 300-400mg/L.

The present invention finds through experimental research that when PBTCA is used alone, a film can be formed on the surface of the carbon steel test piece in the concentration range of 50-100 mg/L, and the corrosion resistance of the formed film can be tested by copper sulfate standard drop solution. 15-25s. When PESA is used alone, it can also form a film on the surface of a carbon steel test piece at a concentration range of 50-100mg/L, and the corrosion resistance of the formed film is 11-20s when tested by copper sulfate standard drop solution.

The present invention finds through research: when PBTCA and PESA are used together for pre-filming, there is a good synergistic effect, which is better than the effect of pre-filming when they are used alone. When the total concentration of the two is 50-100mg/L, the film formed The corrosion resistance is 25 ~ 35s.

The present invention also finds through research that when adding an appropriate amount of sodium molybdate, zinc salt, and benzotriazole on the basis of PBTCA and PESA as the main components, the corrosion resistance of the film can be greatly improved, and the corrosion resistance of the film can be greatly improved. greater than 150s. However, although the pre-film agent composed of PBTCA, PESA, sodium molybdate, zinc salt, and benzotriazole greatly improves the corrosion resistance of the pre-film, the water quality of the pre-film is slightly turbid.

The present invention has found through research that, in the pre-film agent composed of several components such as PBTCA, PESA, sodium molybdate, zinc salt, and benzotriazole, adding a small amount of carboxylic acid-based copolymer can greatly improve the pre-film agent. The water quality keeps it clear and transparent, ensuring that the pre-film liquid after pre-film can be directly converted to normal operation without replacement.

The environment-friendly composite pre-film agent provided by the invention has the following advantages compared with the traditional pre-film agent: (1) the composite pre-film agent provided by the invention has the characteristics of low phosphorus, and the total phosphorus (P) of circulating cooling water in the use process Content <7.5mg·L ^-1 , while the total phosphorus (P) content of the traditional prefilming agent in use is 40mg·L ^-1 ~ 60mg·L ^-1 ; (2) In the composite prefilming agent provided by the present invention, The polymer sodium polyepoxysuccinate used is a biodegradable product, which belongs to a phosphorus-free, biodegradable environment-friendly product; (3) PBTCA in the present invention, polyepoxysuccinic acid, carboxylic acid-based copolymer, benzene There is an obvious pre-film synergistic effect between triazole, molybdate, and zinc salt, thereby greatly reducing the total agent concentration; (4) the composite pre-film agent provided by the invention is used when carbon steel is pre-filmed , the total dosage of chemicals is small, the film formation is fast (48h), and the corrosion resistance of the formed film is good (>150s), which is far superior to that stipulated in the technical regulations for chemical cleaning and pre-filming of circulating cooling water systems (CECS103:99) Pre-film technical index (>10s); (5) when the composite pre-film agent provided by the present invention performs pre-film on the circulating cooling water system, it is not necessary to adjust the pH by adding acid, so no special acid-adding equipment is needed, which not only saves (6) when the composite pre-film agent provided by the present invention performs pre-film, the pre-film liquid can be directly converted to normal operation without replacement and discharge, which not only saves a large amount of Replace the water, and save the cost of adding basic medicament after the traditional pre-film is finished, and also reduce the discharge of waste water, so the present invention can not only save costs, but also reduce waste water discharge; (7) the pre-film formula After being transferred to normal operation, the pre-film agent itself can be directly used as a corrosion and scale inhibitor in normal operation. With the normal operation of the system, the original pre-film agent will gradually reduce to the concentration of normal operation through the sewage system of circulating cooling water At this time, the corrosion and scale inhibition formula with PESA and PBTCA as the main components can be added through supplementary water, or a new corrosion and scale inhibition formula can be added through supplementary water to replace the original pre-film agent. The pre-film agent does not affect the addition of new corrosion and scale inhibition formula.

Detailed ways

The present invention is further described below by way of examples, but not limiting its scope.

The following examples all refer to "Measurement of Corrosion Inhibition Performance of Water Treatment Agents-Rotary Coupon Method" (National Standard of the People's Republic of China GB/T18175-2000) to carry out the rotary coupon pre-coating experiment. The experiment adopts the RCC-II rotary coupon corrosion tester, the temperature is 45°C, the rotation speed is 75r/min, the pre-film test time is 48 hours, the carbon steel test piece is A ₃ carbon steel, and the test water is the circulating cooling water replenishment water of a steel plant , its water quality indicators are: Ca ²⁺ (calculated as CaCO ₃ ) 150-250 mg·L ^-1 , total alkalinity (calculated as CaCO ₃ ) 80-260 mg·L ^-1 , Cl ^- 50-100 mg·L ^-1 , SO ₄ ^2- 50~150 mg·L ^-1 , pH 7.4~8.4.

After the pre-filming, take out the test piece, first rinse the surface with distilled water, then wipe it with absolute ethanol, and then dry it with a hair dryer. Observe the characteristics of the film surface, test the corrosion resistance time of the film with copper sulfate standard drip solution, and evaluate the quality of the film by comparing the time difference between the pre-film test piece and the blank test piece when the red dot appears. Preparation of copper sulfate standard drop solution: weigh 5g of copper sulfate and 15g of sodium chloride and dissolve in 100ml of distilled water.

Example 1

Preparation process: prepare 100.00g each of environment-friendly composite pre-film agent A and B

Preparation of agent A: 65.00g of 2-phosphonic acid group-1,2,4-tricarboxylic acid butane (PBTCA) with a solid content of 50% and 4.80g of acrylic acid/2-methyl-butane with a solid content of 30% Mix and stir 2'-acrylamidopropanesulfonic acid binary copolymer (AA/AMPS) and 19.20 g of water evenly, then add 11.00 g of zinc sulfate heptahydrate and stir to dissolve, and obtain 100.00 g of the required A agent.

Preparation of agent B: 31.2g solid content is 40% sodium polyepoxysuccinate mixed with 63.3g water and stirred evenly, then add 2.5g benzotriazole and 3.0g sodium molybdate dihydrate ( _Na MoO ₄ ·2H ₂ O) was stirred and dissolved to obtain 100 g of B agent to be prepared.

Add agent A and agent B of the above-mentioned prepared agent solution directly to the test water in the ratio of weight ratio A:B=1:1 to carry out the rotating test, add 200mg·L ^-1 to agent A, and add 200mg to agent B ·L ^-1 , the experimental temperature is 45°C, the experimental time is 48h, the water quality of the experimental water is: Ca ²⁺ (calculated as CaCO ₃ ) 150mg·L ^-1 , total alkalinity (calculated as CaCO ₃ ) 126mg·L ^-1 , Cl ^- 67mg·L ^-1 , SO ₄ ^2- 67mg·L ^-1 , pH 7.4. After the pre-film was finished, it was tested with copper sulfate standard drop solution. The experimental results are shown in Table 1.

Based on the dosage of 400mg·L ^-1 of a pre-film agent (200mg·L ^-1 of A agent and 200mg·L ^-1 of B agent), the weight percentage of each component is as follows:

PBTCA 16.25%

PESA 6.24%

AA/AMPS 0.72%

Benzotriazole 1.25%

Na ₂ MoO ₄ 1.28%

_ZnSO4 3.09%

Water 71.17%.

Example 2

Preparation process: prepare 100.00g each of environment-friendly composite pre-film agent A and B

Preparation of Agent A: 66.60g solid content of 2-phosphonic acid group-1,2,4-tricarboxylic acid butane (PBTCA), 2.70g solid content of 30% acrylic acid/2-methyl- Mix and stir 2'-acrylamidopropanesulfonic acid binary copolymer (AA/AMPS) and 18.70 g of water evenly, then add 12.00 g of zinc sulfate heptahydrate and stir to dissolve, and obtain 100.00 g of the required A agent.

Preparation of agent B: 50.00g solid content is 40% sodium polyepoxysuccinate mixed with 16.0g water and stirred evenly, then add 2.00g benzotriazole and 4.00g sodium molybdate dihydrate (Na ₂ MoO ₄ ·2H ₂ O) was stirred and dissolved to obtain 100 g of B agent to be prepared.

Add agent A and agent B of the above-mentioned prepared agent solution directly to the test water in the ratio of weight ratio A:B=1:1 to carry out the rotating test, add 150mg·L ^-1 to agent A, and add 150mg to agent B ·L ^-1 , the experimental temperature is 45°C, the experimental time is 48h, the water quality of the experimental water is: Ca ²⁺ (calculated as CaCO ₃ ) 155mg·L ^-1 , total alkalinity (calculated as CaCO ₃ ) 160mg·L ^-1 , Cl ^- 65mg·L ^-1 , SO ₄ ^2- 56mg·L ^-1 , pH 7.6. After the pre-film was finished, it was tested with copper sulfate standard drop solution. The experimental results are shown in Table 1.

Based on the dosage of 300mg·L ^-1 of a pre-film agent (150mg·L ^-1 for A agent and 150mg·L ^-1 for B agent), the weight percentage is as follows:

PBTCA 16.65%

PESA 10.00%

AA/AMPS 0.41%

Benzotriazole 1.00%

Na ₂ MoO ₄ 1.70%

_ZnSO4 3.37%

Water 66.87%.

Example 3

Preparation process: prepare 100.00g each of environment-friendly composite pre-film agent A and B

Preparation of agent A: 60.00g of 2-phosphonic acid group-1,2,4-tricarboxylic acid butane (PBTCA) with a solid content of 50% and 3.60g of acrylic acid/2-methyl-butane with a solid content of 30% Mix and stir 2'-acrylamidopropanesulfonic acid binary copolymer (AA/AMPS) and 19.60 g of water evenly, then add 16.80 g of zinc sulfate heptahydrate and stir to dissolve, and obtain 100.00 g of the required A agent.

The preparation of agent B: 31.20g solid content is 40% sodium polyepoxysuccinate and 64.50g water mix and stir, then add 2.00g of benzotriazole and 2.30g of sodium molybdate dihydrate (Na ₂ MoO ₄ ·2H ₂ O) was stirred and dissolved to obtain 100.00 g of B agent to be prepared.

Add agent A and agent B of the above-mentioned prepared agent solution directly to the test water in the ratio of weight ratio A:B=1:1 to carry out the rotating test, add 200mg·L ^-1 to agent A, and add 200mg to agent B ·L ^-1 , the experimental temperature is 45°C, the experimental time is 48h, the water quality of the experimental water is: Ca ²⁺ (calculated as CaCO ₃ ) 230mg·L ^-1 , total alkalinity (calculated as CaCO ₃ ) 240mg·L ^-1 , Cl ^- 76mg·L ^-1 , SO ₄ ^2- 88mg·L ^-1 , pH 8.0. After the pre-film was finished, it was tested with copper sulfate standard drop solution. The experimental results are shown in Table 1.

Based on the dosage of a pre-film agent of 400mg·L ^-1 (a dose of 200mg·L ^-1 , B dose of 200mg·L ^-1 ), the weight percentage is as follows:

PBTCA 15.00%

PESA 6.24%

AA/AMPS 0.54%

Benzotriazole 1.00%

Na ₂ MoO ₄ 0.98%

_ZnSO4 4.71%

Water 71.53%.

Example 4

Preparation process: prepare 100.00g each of environment-friendly composite pre-film agent A and B

Preparation of agent A: 50.00g of 2-phosphonic acid group-1,2,4-tricarboxylic acid butane (PBTCA) with a solid content of 50% and 4.70g of acrylic acid/2-methyl-butane with a solid content of 30% Mix and stir 2'-acrylamidopropanesulfonic acid binary copolymer (AA/AMPS) and 32.00 g of water evenly, then add 13.30 g of zinc sulfate heptahydrate and stir to dissolve, and obtain 100.00 g of A agent to be prepared.

The preparation of agent B: 43.80g solid content is 40% sodium polyepoxysuccinate and 51.00g water are mixed and stirred evenly, then add 1.50g of benzotriazole and 3.70g of sodium molybdate dihydrate (Na ₂ MoO ₄ ·2H ₂ O) was stirred and dissolved to obtain 100.00 g of B agent to be prepared.

Add agent A and agent B of the above-mentioned prepared agent solution directly to the test water in the ratio of weight ratio A:B=1:1 to carry out the rotating test, add 200L ^-1 agent A, add 200mg·L agent B ^-1 , the experiment temperature is 45°C, the experiment time is 48h, the water quality of the experiment is: Ca ²⁺ (calculated as CaCO ₃ ) 210mg·L ^-1 , total alkalinity (calculated as CaCO ₃ ) 220mg·L ^-1 , Cl ^- 80mg ·L ^-1 , SO ₄ ^2- 108 mg·L ^-1 , pH 8.1. After the pre-film was finished, it was tested with copper sulfate standard drop solution. The experimental results are shown in Table 1.

Based on the dosage of a pre-film agent of 400mg·L ^-1 (a dose of 200mg·L ^-1 , B dose of 200mg·L ^-1 ), the weight percentage is as follows:

PBTCA 12.50%

PESA 8.7%

AA/AMPS 0.71%

Benzotriazole 0.75%

Na ₂ MoO ₄ 1.58%

_ZnSO4 3.73%

Water 71.97%.

Example 5

Preparation process: prepare 100.00g each of environment-friendly composite pre-film agent A and B

Preparation of Agent A: 68.60g solid content of 2-phosphonic acid group-1,2,4-tricarboxylic acid butane (PBTCA), 9.60g solid content of 30% acrylic acid/2-methyl- Mix and stir 2'-acrylamidopropanesulfonic acid binary copolymer (AA/AMPS) and 11.70 g of water evenly, then add 10.10 g of zinc sulfate heptahydrate and stir to dissolve, and obtain 100.00 g of the required A agent.

The preparation of agent B: 42.90g solid content is 40% sodium polyepoxysuccinate and 53.00g water mix and stir, then add 2.30g of benzotriazole and 1.80g of sodium molybdate dihydrate (Na ₂ MoO ₄ ·2H ₂ O) was stirred and dissolved to obtain 100.00 g of B agent to be prepared.

Add agent A and agent B of the above-mentioned prepared agent solution directly to the experimental water in the ratio of weight ratio A:B=1:1 to carry out the rotating test, and add 175mg·L ^-1 to agent A and 175mg to agent B ·L ^-1 , the experimental temperature is 45°C, the experimental time is 48h, the water quality of the experimental water is: Ca ²⁺ (calculated as CaCO ₃ ) 130mg·L ^-1 , total alkalinity (calculated as CaCO ₃ ) 126mg·L ^- 1, Cl ^- 56mg·L ^-1 , SO ₄ ^2- 80mg·L ^-1 , pH 7.7. After the pre-film was finished, it was tested with copper sulfate standard drop solution. The experimental results are shown in Table 1.

Based on the dosage of 350mg·L ^-1 of a pre-filming agent (175mg·L ^-1 of A agent and 175mg·L ^-1 of B agent), the weight percentage is as follows:

PBTCA 17.15%

PESA 8.58%

AA/AMPS 1.44%

Benzotriazole 1.15%

Na ₂ MoO ₄ 0.77%

_ZnSO4 2.84%

Water 68.07%.

Example 6

Preparation process: prepare 100.00g each of environment-friendly composite pre-film agent A and B

Preparation of agent A: 57.20g solid content of 2-phosphonic acid group-1,2,4-tricarboxylic acid butane (PBTCA), 4.00g solid content of 30% acrylic acid/2-methyl- Mix and stir 2'-acrylamidopropanesulfonic acid binary copolymer (AA/AMPS) and 28.80 g of water evenly, then add 10.00 g of zinc sulfate heptahydrate and stir to dissolve, and obtain 100.00 g of the A agent to be prepared.

The preparation of agent B: 57.00g solid content is 40% sodium polyepoxysuccinate and 39.20g water are mixed and stirred evenly, then add 2.20g of benzotriazole and 1.60g of sodium molybdate dihydrate (Na ₂ MoO ₃ .2H ₂ O) was stirred and dissolved to obtain 100.00 g of B agent to be prepared.

Add agent A and agent B of the above-mentioned prepared agent solution directly to the experimental water in the ratio of weight ratio A:B=1:1 to carry out the rotating test, and add 175mg·L ^-1 to agent A and 175mg to agent B ·L ^-1 , the experimental temperature is 45°C, the experimental time is 48h, the water quality of the experimental water is: Ca ²⁺ (calculated as CaCO ₃ ) 185mg·L ^-1 , total alkalinity (calculated as CaCO ₃ ) 166mg·L ^-1 , Cl ^- 79 mg·L ^-1 , SO ₄ ^2- 81 mg·L ^-1 , pH 8.2. After the pre-film was finished, it was tested with copper sulfate standard drop solution. The experimental results are shown in Table 1.

Based on the dosage of 350mg·L ^-1 of a pre-filming agent (175mg·L ^-1 of A agent and 175mg·L ^-1 of B agent), the weight percentage is as follows:

PBTCA 14.30%

PESA 11.40%

AA/AMPS 0.60%

Benzotriazole 1.10%

Na ₂ MoO ₄ 0.68%

_ZnSO4 2.81%

Water 69.11%.

Example 7

Preparation process: prepare 100.00g each of environment-friendly composite pre-film agent A and B

Preparation of agent A: 51.60g solid content of 2-phosphonic acid group-1,2,4-tricarboxylic acid butane (PBTCA), 2.80g solid content of 30% acrylic acid/2-methyl- Mix and stir 2'-acrylamidopropanesulfonic acid binary copolymer (AA/AMPS) and 35.60 g of water evenly, then add 10.00 g of zinc sulfate heptahydrate and stir to dissolve, and obtain 100.00 g of the required A agent.

The preparation of agent B: 64.5g solid content is 40% sodium polyepoxysuccinate and 30.1g water mix and stir, then add 2.8g of benzotriazole and 2.6g of sodium molybdate dihydrate (Na ₂ MoO ₃ ·2H ₂ O) stirring and dissolving to obtain 100g of B agent to be prepared.

Add agent A and agent B of the above-mentioned prepared agent solution directly to the experimental water in the ratio of weight ratio A:B=1:1 to carry out the rotating test, and add 175mg·L ^-1 to agent A and 175mg to agent B ·L ^-1 , the experimental temperature is 45°C, the experimental time is 48h, the water quality of the experimental water is: Ca ²⁺ (calculated as CaCO ₃ ) 150mg·L ^-1 , total alkalinity (calculated as CaCO ₃ ) 144mg·L ^-1 , Cl ^- 101 mg·L ^-1 , SO ₄ ^2- 58 mg·L ^-1 , pH 8.0. After the pre-film was finished, it was tested with copper sulfate standard drop solution. The experimental results are shown in Table 1.

Based on the dosage of 350mg·L ^-1 for one pre-film agent (175mg·L ^-1 for A dose and 175mg·L ^-1 for B dose), the weight percentage is as follows:

PBTCA 12.90%

PESA 12.90%

AA/AMPS 0.42%

Benzotriazole 1.4%

Na ₂ MoO ₄ 1.11%

_ZnSO4 2.81%

Water 68.46%.

Example 8

Preparation process: prepare 100.00g each of environment-friendly composite pre-film agent A and B

Preparation of Agent A: 50.00g of 2-phosphonic acid group-1,2,4-tricarboxylic butane (PBTCA) with a solid content of 50%, 5.00g of acrylic acid/2-methyl-butane with a solid content of 30% Mix and stir 2'-acrylamidopropanesulfonic acid binary copolymer (AA/AMPS) and 36.10 g of water evenly, then add 8.90 g of zinc sulfate heptahydrate and stir to dissolve, and obtain 100.00 g of the required A agent.

The preparation of agent B: 56.30g solid content is 40% sodium polyepoxysuccinate and 38.40g water mix and stir, then add 1.50g of benzotriazole and 3.80g of sodium molybdate dihydrate (Na ₂ MoO ₃ .2H ₂ O) was stirred and dissolved to obtain 100.00 g of B agent to be prepared.

Add agent A and agent B of the above-mentioned prepared agent solution directly to the test water in the ratio of weight ratio A:B=1:1 to carry out the rotating test, add 200mg·L ^-1 to agent A, and add 200mg to agent B ·L ^-1 , the experimental temperature is 45°C, the experimental time is 48h, the water quality of the experimental water is: Ca ²⁺ (calculated as CaCO ₃ ) 110mg·L ^-1 , total alkalinity (calculated as CaCO ₃ ) 132mg·L ^-1 , Cl ^- 96 mg·L ^-1 , SO ₄ ^2- 81 mg·L ^-1 , pH 7.8. After the pre-film was finished, it was tested with copper sulfate standard drop solution. The experimental results are shown in Table 1.

Based on the dosage of 400mg·L ^-1 for one pre-filming agent (200mg·L ^-1 for A agent, 200mg·L ^-1 for B agent), the weight percentage is as follows:

PBTCA 12.50%

PESA 11.26%

AA/AMPS 0.75%

Benzotriazole 0.75%

Na ₂ MoO ₄ 1.62%

_ZnSO4 2.50%

Water 70.62%.

Example 9

Preparation process: prepare 100.00g each of environment-friendly composite pre-film agent A and B

Preparation of Agent A: 50.00g of 2-phosphonic acid-1,2,4-tricarboxylic butane (PBTCA) with a solid content of 50%, 2.00g of acrylic acid/2-methyl-butane with a solid content of 30% 2'-acrylamidopropanesulfonic acid/hydroxypropyl acrylate terpolymer (AA/AMPS/HPA), 39.10g of water were mixed and stirred evenly, then 8.90g of zinc sulfate heptahydrate was added and stirred to dissolve, and the desired The prepared 100.00g agent A.

The preparation of agent B: 62.50g solid content is 40% sodium polyepoxysuccinate and 34.50g water are mixed and stirred evenly, then add 1.60g of benzotriazole and 1.40g of sodium molybdate dihydrate (Na ₂ MoO ₃ .2H ₂ O) was stirred and dissolved to obtain 100.00 g of B agent to be prepared.

Add agent A and agent B of the above-mentioned prepared agent solution directly to the test water in the ratio of weight ratio A:B=1:1 to carry out the rotating test, add 200mg·L ^-1 to agent A, and add 200mg to agent B ·L ^-1 , the experimental temperature is 45°C, the experimental time is 48h, the water quality of the experimental water is: Ca ²⁺ (calculated as CaCO ₃ ) 255mg·L ^-1 , total alkalinity (calculated as CaCO ₃ ) 240mg·L ^-1 , Cl ^- 110 mg·L ^-1 , SO ₄ ^2- 102 mg·L ^-1 , pH 8.2. After the pre-film was finished, it was tested with copper sulfate standard drop solution. The experimental results are shown in Table 1.

Based on the dosage of a pre-film agent of 400mg·L ^-1 (a dose of 200mg·L ^-1 , B dose of 200mg·L ^-1 ), the weight percentage is as follows:

PBTCA 12.50%

PESA 12.50%

AA/AMPS/HPA 0.30%

Benzotriazole 0.80%

Na ₂ MoO ₄ 0.60%

_ZnSO4 2.50%

Water 70.80%.

comparative example

According to the concentration of sodium hexametaphosphate 170mg·L ^-1 , zinc sulfate 80mg·L ^-1 , and AA/AMPS/HPA copolymer 30mg·L ^-1 , the test water was added to carry out the pre-film test of the rotary hanging film. The quality of the test water is: Ca2 ⁺ (calculated as CaCO ₃ ) 125mg·L ^-1 , total alkalinity (calculated as CaCO ₃ ) 150mg·L ^-1 , Cl ^- 78mg·L ^-1 , SO ₄ ^2- 98mg·L ^-1 , pH8.0 . During the experiment, sulfamic acid was used to control the pH of the experimental water to 5.5-6.5, the experimental temperature was 45°C, and the experimental time was 48 hours.

Table 1 Experimental results

The total dosage of pre-coating agents (calculated as solids) mg·L ^-1 Phosphorus content of pre-coating agent (calculated as P) mg·L ^-1 Copper sulfate color development time S Carbon steel corrosion rate mm·a ^-1 Example 1 115 7.2 197 0.0044

Example 2 99 5.5 154 0.0106 Example 3 114 6.6 182 0.0039 Example 4 113 5.5 179 0.0020 Example 5 112 6.6 181 0.0081 Example 6 108 5.5 178 0.0057 Example 7 114 5.0 169 0.0096 Example 8 118 5.5 172 0.0066 Example 9 117 5.5 170 0.0046 comparative example 280 52 twenty three 0.0656

Claims (5)

1. one kind is used for the compound prefilming agent of environment-friendly type that the pre-film of recirculating cooling water system is handled, it is characterized in that the compound prefilming agent of described environment-friendly type is by 2-phosphonate group-1,2,4-butane tricarboxylate, polyepoxy sodium succinate, carboxylic acid-based copolymer, benzotriazole, Sodium orthomolybdate, zinc sulfate and water are formed, and the weight percent of its component is:

2-phosphonate group-1,2,4-butane tricarboxylate 2%～18%

Polyepoxy sodium succinate 6%～15%

The carboxylic acid-based copolymer 0.3%～2%

Benzotriazole 0.5%～2%

Sodium orthomolybdate 0.5%～2%

Zinc sulfate 2%～5%

All the other are water, and its gross weight satisfies 100%.

2. compound prefilming agent according to claim 1 is characterized in that described polyepoxy sodium succinate structural formula is:

Wherein, polymerization degree n is 4～50 integer.

3. compound prefilming agent according to claim 1, it is characterized in that described carboxylic acid-based copolymer for the carboxylic acid-based copolymer for vinylformic acid/2-methyl-2 '-acrylamido propane sulfonic acid copolymer or vinylformic acid/2-methyl-2 '-acrylamido propane sulfonic acid/Propylene glycol monoacrylate terpolymer.

4. compound prefilming agent according to claim 1 is characterized in that described zinc sulfate is Zinc Sulphate Heptahydrate.

5. the using method of the compound prefilming agent of environment-friendly type as claimed in claim 1 is characterized in that before the normal operation of recirculating cooling water system, directly the compound prefilming agent of this environment-friendly type is added in the recirculated cooling water to get final product, and add-on is 300～400mg/L.