CN113789517B - Rinsing and passivation integrated reagent and process in chemical cleaning of power station boiler - Google Patents

Abstract

The invention discloses a rinsing and passivating integrated reagent and a process in chemical cleaning of a power station boiler, wherein after chemical cleaning and acid cleaning, water washing is implemented after the chemical cleaning and acid cleaning are qualified, after a cleaning system is circulated, a rinsing agent, a corrosion inhibitor and an auxiliary agent are added into the chemical cleaning system, wherein the mass concentration of the rinsing agent in the chemical cleaning system is 0.1-50%, the mass concentration of the corrosion inhibitor is 0.1-0.8%, and the mass concentration of the auxiliary agent is 0.01-0.03%; adjusting the pH value of the chemical cleaning system to 2-7 by using ammonia water, starting rinsing, adjusting the pH value of the cleaning system to 8-12 by using the ammonia water after iron ions in the system are balanced, starting passivation, and discharging passivation solution after 2-8 hours of passivation. The rinsing and passivating processes of the invention are completed in one step. The method is easy to realize, the passive film is complete and compact, and the effect is stable. The invention is suitable for the rinsing and passivating processes after chemical cleaning of various boiler types.

Description

Rinsing and passivating integrated reagent and process for chemical cleaning of power station boiler

Technical Field

The invention belongs to the technical field of chemical cleaning, and particularly relates to a rinsing and passivating integrated reagent and a process in chemical cleaning of a power station boiler.

Background

The chemical cleaning is an effective method for removing operation scale and stopping corrosion products on the inner surface of the heat exchange tube of the power station boiler, and can improve the heat exchange efficiency of the boiler and reduce the coal consumption of the boiler. The chemical cleaning comprises the processes of acid cleaning, water washing after acid cleaning, rinsing, passivation and the like. And secondary rust generated on the metal surface of the boiler heat exchange tube in the water washing process after acid washing can be removed by rinsing. The passivation can form a protective film on the metal surface of the heat exchange tube of the boiler after chemical cleaning to prevent the corrosion of the metal in the atmospheric environment after the cleaning of the boiler and before the starting of the boiler.

The most common rinsing and passivating processes for chemical cleaning of power station boilers are citric acid rinsing, ammonia water and hydrogen peroxide passivating processes. The disadvantages are: 1) The rinsing-to-passivation process needs dilution and replacement of rinsing liquid, and the process needs consumption of a large amount of desalted water and generation of a large amount of wastewater, which does not meet the environmental protection requirement; 2) The process is difficult to control, the stability of hydrogen peroxide is greatly changed along with the change of temperature and pH in the actual application process, and if the passivation process is improperly controlled, the quality of a passivation film is deteriorated, and secondary rust is easily generated after passivation. The power station boiler can realize one-step completion of acid washing, rinsing and passivation by using the EDTA as a cleaning agent, but the EDTA used as the cleaning agent in the cleaning process is high in price, and the EDTA cleaning utilization rate is not high.

Disclosure of Invention

In order to solve the problems in the prior art, the invention aims to provide a rinsing and passivating integrated reagent and a rinsing and passivating integrated process in chemical cleaning of a power station boiler. The method is suitable for the rinsing and passivating processes after chemical cleaning of various boiler types. The invention has the advantages of small wastewater amount in the rinsing passivation process, good passivation effect, easy realization and low price.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

a rinsing and passivating integrated reagent for chemical cleaning of a power station boiler comprises the following raw materials in percentage by mass:

0.1 to 50 percent of rinsing agent;

0.1 to 0.8 percent of corrosion inhibitor;

0.01 to 0.03 percent of auxiliary agent;

and the balance of demineralized water;

the rinsing agent comprises 5-30% of ethylenediamine tetraacetic acid, 1-40% of aminotriacetic acid, 5-40% of hydroxyethylidene diphosphonic acid, 5-30% of citric acid and the balance of demineralized water.

As a further improvement of the invention, the corrosion inhibitor comprises 5-30% of urotropin, 3-15% of hydroxyethyl imidazoline, 0.1-10% of ethanolamine, 1-10% of alkylphenol polyoxyethylene ether and the balance of demineralized water.

As a further improvement of the invention, the auxiliary agent is one or a mixture of more than one of defoamer, hydrazine and sodium erythorbate in any proportion.

As a further improvement of the invention, the pH value of the rinsing agent is 2-7, and ammonia water is used for adjusting the pH value.

An integrated process of a rinsing and passivating integrated reagent in chemical cleaning of a power station boiler comprises the following steps:

after the water washing is finished after the acid washing in the chemical cleaning process, adding a rinsing and passivating integrated reagent in the chemical cleaning of the power station boiler into a chemical cleaning system; the integrated rinsing and passivation process is carried out at the temperature of 40-95 ℃, ammonia water is used for adjusting the pH value of a cleaning system to 8-12 in the rinsing conversion passivation process, and the passivation time is 2-8 h.

As a further improvement of the invention, the pickling medium is hydrochloric acid, nitric acid, glycolic acid + formic acid or citric acid.

As a further improvement of the invention, the power station boiler is a 100-1000 MW subcritical or supercritical boiler or ultra supercritical boiler. .

Compared with the prior art, the invention has the following advantages:

the integrated reagent has strong adaptability, can be used for rinsing and passivating processes after various acid pickles, and a formed passivation film is complete and compact and has a good passivation effect when the process is used for rinsing and passivating.

The integrated process is simple and easy to realize, and the rinsing and the passivation are finished in one step, so that the time is saved. The invention does not need to discharge or dilute the rinsing liquid, has less waste liquid amount and high environmental protection property of the process.

Detailed Description

To make the features and effects of the present invention comprehensible to those skilled in the art, general description and definitions are made below with reference to terms and expressions mentioned in the specification and claims. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

The theory or mechanism described and disclosed herein, whether correct or incorrect, should not limit the scope of the present invention in any way, i.e., the present disclosure may be practiced without being limited by any particular theory or mechanism.

All features defined herein as numerical ranges or percentage ranges, such as values, amounts, levels and concentrations, are for brevity and convenience only. Accordingly, the description of numerical ranges or percentage ranges should be considered to cover and specifically disclose all possible subranges and individual numerical values (including integers and fractions) within the range.

In this document, unless otherwise specified, "comprising," "including," "having," or similar terms, shall mean "consisting of 8230; \8230, composition" and "consisting essentially of 8230; \8230, composition" such as "A comprises a" shall mean "A comprises a and the other" and "A comprises a only".

In this context, for the sake of brevity, not all possible combinations of features in the various embodiments or examples are described. Therefore, the respective features in the respective embodiments or examples may be arbitrarily combined as long as there is no contradiction between the combinations of the features, and all the possible combinations should be considered as the scope of the present specification.

The invention aims to provide a rinsing and passivating integrated reagent for chemical cleaning of a power station boiler, which comprises the following raw materials in percentage by mass:

0.1 to 50 percent of rinsing agent;

0.1 to 0.8 percent of corrosion inhibitor;

0.01 to 0.03 percent of auxiliary agent;

and the balance of demineralized water;

or as: the mass concentration of the rinsing agent is 0.1-50%, the mass concentration of the corrosion inhibitor is 0.1-0.8%, and the mass concentration of the auxiliary agent is 0.01-0.03%; the desalted water is used as a solvent.

The rinsing agent comprises 5-30% of ethylenediamine tetraacetic acid, 1-40% of aminotriacetic acid, 5-40% of hydroxyethylidene diphosphonic acid, 5-30% of citric acid and the balance of demineralized water.

The rinsing agent is formed by mixing ethylene diamine tetraacetic acid, nitrilotriacetic acid, hydroxyethylidene diphosphonic acid, citric acid, ammonia water and demineralized water, wherein the mass percent of the ethylene diamine tetraacetic acid, the mass percent of the nitrilotriacetic acid, the mass percent of the hydroxyethylidene diphosphonic acid and the mass percent of the citric acid in the rinsing agent are respectively 5-30%, 1-40% and 5-30%, the pH value is adjusted by using the ammonia water, and the balance is the demineralized water;

the corrosion inhibitor is formed by mixing 5-30% of urotropin, 3-15% of hydroxyethyl imidazoline, 0.1-10% of ethanolamine, 1-10% of alkylphenol polyoxyethylene and the balance of demineralized water;

the auxiliary agent is one or a mixture of more than one of defoaming agent, hydrazine and sodium erythorbate in any proportion.

The second purpose of the invention is to provide a rinsing and passivation integrated process in chemical cleaning of a power station boiler, which is realized in the chemical cleaning process, and after water washing is finished after acid washing in the chemical cleaning process, a rinsing agent with the mass fraction of 0.1-50%, a corrosion inhibitor with the mass fraction of 0.1-0.8%, an auxiliary agent with the mass fraction of 0.01-0.03% and the balance of desalted water are added into a chemical cleaning system; the pH value of the system rinsing process is 2-7; rinsing and passivating are finished in one step, rinsing liquid does not need to be discharged or diluted in the passivating process, the pH of a cleaning system is adjusted to be 8-12, and the passivating time is 2-8 hours; the temperature of the rinsing and passivating process of the process is 40-95 ℃.

The rinsing and passivating integrated process is suitable for rinsing and passivating processes after pickling by using hydrochloric acid, nitric acid, glycolic acid, formic acid and citric acid as pickling media for a power station boiler.

The invention will be further illustrated with reference to the following specific examples. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. Further, it should be understood that various changes or modifications of the present invention may be made by those skilled in the art after reading the teaching of the present invention, and such equivalents may fall within the scope of the present invention as defined in the appended claims.

The following examples use instrumentation conventional in the art. The experimental procedures, in which specific conditions are not noted in the following examples, are generally carried out under conventional conditions or conditions recommended by the manufacturers. The various starting materials used in the examples which follow, unless otherwise indicated, are conventional commercial products having specifications which are conventional in the art. In the description of the present invention and the following examples, "%" represents weight percent, "parts" represents parts by weight, and proportions represent weight ratios, unless otherwise specified.

Example 1:

hydrochloric acid is used as an acid washing medium in a 300MW natural circulation drum furnace, a rinsing agent with the mass fraction of 10%, a corrosion inhibitor with the mass fraction of 0.2%, a defoaming agent with the mass fraction of 0.3% and the balance demineralized water are added into a chemical cleaning system after the pickling and the water washing are qualified.

Wherein the rinsing agent is composed of 10% by mass of ethylenediaminetetraacetic acid, 2% by mass of nitrilotriacetic acid, 10% by mass of hydroxyethylidene diphosphonic acid, 5% by mass of citric acid, ammonia water is used for adjusting the pH value to 5.0, and the balance is demineralized water.

The corrosion inhibitor comprises, by mass, 10% of urotropin, 5% of hydroxyethyl imidazoline, 1% of ethanolamine, 2% of alkylphenol polyoxyethylene and the balance of demineralized water.

After the rinse was complete, the system was switched to passivation by adjusting the pH to 10.1 with ammonia. Rinsing and passivating temperatures 50 ℃.

And after passivation, checking the state of the passivation film, wherein the passivation film is complete and compact.

Example 2:

citric acid is used as an acid washing medium in a certain 600MW supercritical boiler, and a rinsing agent with the mass fraction of 15%, a corrosion inhibitor with the mass fraction of 0.2%, a defoaming agent with the mass fraction of 0.3% and the balance demineralized water are added into a chemical cleaning system after the water after acid washing is qualified.

Wherein the rinsing agent is 15 percent of ethylene diamine tetraacetic acid, 2 percent of nitrilotriacetic acid, 5 percent of hydroxyethylidene diphosphonic acid and 10 percent of citric acid by mass, the pH value is adjusted to 5.2 by using ammonia water, and the balance is desalted water.

The corrosion inhibitor comprises 15 mass percent of urotropin, 4 mass percent of hydroxyethyl imidazoline, 1 mass percent of ethanolamine, 3 mass percent of alkylphenol ethoxylates and the balance of desalted water.

After the rinse was complete, the system was switched to passivation by adjusting the pH to 10.1 with ammonia. Rinsing and passivation temperature 55 ℃.

And after passivation, checking the state of the passivation film, wherein the passivation film is complete and compact.

Example 3:

a1000 MW supercritical boiler uses glycolic acid and formic acid as an acid washing medium, and after the supercritical boiler is washed by water after acid washing to be qualified, a rinsing agent with the mass fraction of 20%, a corrosion inhibitor with the mass fraction of 0.3%, a defoaming agent with the mass fraction of 0.3% and the balance of desalted water are added into a chemical cleaning system.

Wherein the rinsing agent is composed of 20% by mass of ethylenediaminetetraacetic acid, 2% by mass of nitrilotriacetic acid, 5% by mass of hydroxyethylidene diphosphonic acid and 5% by mass of citric acid, the pH value is adjusted to 6.0 by using ammonia water, and the balance is demineralized water.

The corrosion inhibitor comprises 15 mass percent of urotropin, 3 mass percent of hydroxyethyl imidazoline, 1 mass percent of ethanolamine, 3 mass percent of alkylphenol polyoxyethylene and the balance of desalted water.

After the rinse was complete, the system was switched to passivation by adjusting the pH to 10.1 with ammonia. Rinsing and passivating temperature 60 ℃.

And after passivation, checking the state of the passivation film, wherein the passivation film is complete and compact.

Example 4:

hydrochloric acid is used as an acid washing medium in a 300MW natural circulation drum furnace, a rinsing agent with the mass fraction of 0.1%, a corrosion inhibitor with the mass fraction of 0.1%, hydrazine and sodium erythorbate with the mass fraction of 0.01% and the balance of desalted water are added into a chemical cleaning system after the acid washing is qualified.

Wherein the rinsing agent is 5 percent of ethylene diamine tetraacetic acid, 1 percent of nitrilotriacetic acid, 5 percent of hydroxyethylidene diphosphonic acid and 10 percent of citric acid by mass, the pH value is adjusted to 2.6 by using ammonia water, and the balance is desalted water.

In the corrosion inhibitor, the mass percent of urotropin is 5%, the mass percent of hydroxyethyl imidazoline is 3%, the mass percent of ethanolamine is 0.1%, the mass percent of alkylphenol ethoxylates is 1%, and the balance is desalted water.

After the rinse was complete, the system was switched to passivation by adjusting the pH to 8.2 with ammonia. Rinsing and passivating temperature 40 ℃.

And after passivation, checking the state of the passivation film, wherein the passivation film is complete and compact.

Example 5:

citric acid is used as an acid washing medium in a certain 600MW supercritical boiler, and a rinsing agent with the mass fraction of 20%, a corrosion inhibitor with the mass fraction of 0.5%, a defoaming agent with the mass fraction of 0.02% and the balance demineralized water are added into a chemical cleaning system after the water after acid washing is qualified.

Wherein the rinsing agent comprises 10 percent of ethylene diamine tetraacetic acid, 20 percent of nitrilotriacetic acid, 40 percent of hydroxyethylidene diphosphonic acid and 10 percent of citric acid by mass, ammonia water is used for adjusting the pH value to 6.0, and the balance is desalted water.

The corrosion inhibitor comprises, by mass, 20% of urotropin, 10% of hydroxyethyl imidazoline, 6% of ethanolamine, 5% of alkylphenol polyoxyethylene and the balance of demineralized water.

After the rinse was complete, the system was switched to passivation by adjusting the pH to 10.2 with ammonia. Rinsing and passivation temperature 55 ℃.

And after passivation, checking the state of the passivation film, wherein the passivation film is complete and compact.

Example 6:

a1000 MW supercritical boiler uses glycolic acid and formic acid as pickling media, and after the pickling is finished and the boiler is washed to be qualified by water, 45 mass percent of rinsing agent, 0.7 mass percent of corrosion inhibitor, 0.03 mass percent of defoaming agent, hydrazine, sodium erythorbate and the balance of desalted water are added into a chemical cleaning system.

Wherein the rinsing agent is composed of 30% by mass of ethylenediaminetetraacetic acid, 20% by mass of nitrilotriacetic acid, 15% by mass of hydroxyethylidene diphosphonic acid, 30% by mass of citric acid, ammonia water for adjusting the pH to 4.7, and the balance demineralized water.

The corrosion inhibitor comprises 30 mass percent of urotropin, 15 mass percent of hydroxyethyl imidazoline, 10 mass percent of ethanolamine, 10 mass percent of alkylphenol polyoxyethylene, and the balance of demineralized water.

After the rinse was complete, the system was switched to passivation using ammonia to adjust the pH to 10.1. The rinsing and passivating temperature was 65 ℃.

And after passivation, checking the state of the passivation film, wherein the passivation film is complete and compact.

Example 7:

hydrochloric acid is used as an acid washing medium in a 300MW natural circulation drum furnace, a rinsing agent with the mass fraction of 0.1%, a corrosion inhibitor with the mass fraction of 0.1%, sodium erythorbate with the mass fraction of 0.01% and the balance demineralized water are added into a chemical cleaning system after the acid washing is qualified by water washing.

Wherein the rinsing agent is 5 percent of ethylene diamine tetraacetic acid, 40 percent of nitrilotriacetic acid, 5 percent of hydroxyethylidene diphosphonic acid and 10 percent of citric acid by mass, the pH is adjusted to 3.0 by using ammonia water, and the balance is desalted water.

In the corrosion inhibitor, the mass percent of urotropin is 5%, the mass percent of hydroxyethyl imidazoline is 3%, the mass percent of ethanolamine is 0.1%, the mass percent of alkylphenol ethoxylates is 1%, and the balance is desalted water.

After the rinse was complete, the system was switched to passivation by adjusting the pH to 9.1 with ammonia. Rinsing and passivating temperature 80 ℃.

And after passivation, checking the state of the passivation film, wherein the passivation film is complete and compact.

Example 8:

hydrochloric acid is used as an acid washing medium in a 300MW natural circulation drum furnace, and a rinsing agent with the mass fraction of 0.1%, a corrosion inhibitor with the mass fraction of 0.1%, hydrazine with the mass fraction of 0.01% and the balance demineralized water are added into a chemical cleaning system after the water washing is qualified after the acid washing.

Wherein the rinsing agent is composed of 30% by mass of ethylenediamine tetraacetic acid, 20% by mass of nitrilotriacetic acid, 5% by mass of hydroxyethylidene diphosphonic acid, 10% by mass of citric acid, ammonia water is used for adjusting the pH value to 5, and the balance is demineralized water.

In the corrosion inhibitor, the mass percent of urotropin is 5%, the mass percent of hydroxyethyl imidazoline is 3%, the mass percent of ethanolamine is 0.1%, the mass percent of alkylphenol ethoxylates is 1%, and the balance is desalted water.

After the rinse was complete, the system was switched to passivation by adjusting the pH to 10.0 with ammonia. The rinsing and passivation temperature was 95 ℃.

And after passivation, checking the state of the passivation film, wherein the passivation film is complete and compact.

Examples 1 to 8 the cleaning quality was evaluated as follows:

the foregoing is only a preferred embodiment of the present invention, and it should be noted that those skilled in the art can make various improvements and modifications without departing from the principle of the present invention, and these improvements and modifications should also be construed as the protection scope of the present invention.

Finally, it should be noted that the above embodiments are only used for illustrating the technical solutions of the present invention and not for limiting the protection scope of the present invention, and although the present invention is described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions can be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims (6)

1. The integrated reagent for rinsing and passivating in chemical cleaning of the power station boiler is characterized by comprising the following raw materials in percentage by mass:

0.1 to 50 percent of rinsing agent;

0.1 to 0.8 percent of corrosion inhibitor;

0.01 to 0.03 percent of auxiliary agent;

and the balance of demineralized water;

the rinsing agent comprises 5-30% of ethylenediamine tetraacetic acid, 1-40% of nitrilotriacetic acid, 5-40% of hydroxyethylidene diphosphonic acid, 5-30% of citric acid and the balance of demineralized water;

the corrosion inhibitor comprises 5-30% of urotropin, 3-15% of hydroxyethyl imidazoline, 0.1-10% of ethanolamine, 1-10% of alkylphenol polyoxyethylene and the balance of demineralized water;

after the water washing is finished after the acid washing in the chemical cleaning process, adding a rinsing and passivating integrated reagent in the chemical cleaning of the power station boiler into a chemical cleaning system; rinsing and passivating at 40-95 ℃, adjusting the pH of a cleaning system to 8-12 by using ammonia water in the rinsing conversion passivation process, and passivating for 2-8 h.

2. The integrated agent for rinsing and passivating in chemical cleaning of the utility boiler as claimed in claim 1, wherein the auxiliary agent is one or more of a mixture of antifoaming agent, hydrazine and sodium erythorbate in any proportion.

3. The integrated agent for rinsing and passivating in chemical cleaning of the utility boiler according to claim 1, wherein the pH of the rinsing agent is 2-7, and the pH is adjusted by using ammonia water.

4. The integrated process for the rinsing and passivation of the integrated reagent in the chemical cleaning of the utility boiler is characterized by comprising the following steps of:

after the water washing is finished after the acid washing in the chemical cleaning process, adding a rinsing and passivating integrated reagent in the chemical cleaning of the power station boiler into a chemical cleaning system; rinsing and passivating at 40-95 ℃, adjusting the pH of a cleaning system to 8-12 by using ammonia water in the rinsing conversion passivation process, and passivating for 2-8 h.

5. The integrated process of claim 4, the pickling medium being hydrochloric acid, nitric acid, glycolic acid + formic acid, or citric acid.

6. The integrated process of claim 4, the utility boiler being a 100-1000 MW subcritical or supercritical or ultra supercritical boiler.