Water quality stabilizer suitable for in-furnace treatment of medium-pressure, high-pressure or ultrahigh-pressure boiler

Abstract

The invention discloses a water quality stabilizer suitable for in-furnace treatment of medium-pressure, high-pressure and ultrahigh-pressure boilers and a preparation method of the water quality stabilizer. The water quality stabilizer comprises polyamine organic amines, an organic deoxidant, high-molecular polymeric salt, a silt adjusting agent and pure water. According to the water quality stabilizer disclosed by the invention, one medicament can replace three medicaments of ammonia water, hydrazine and trisodium phosphate added in a traditional boiler, the water quality stabilizer has multiple functions of film forming, corrosion inhibition, deoxygenization, passivation, scale inhibition, scale dissolution, dispersion, chelation, water quality stabilization and the like, meanwhile, the discharge capacity of the boiler can be greatly reduced, the heat energy loss and the water waste can be reduced, and the heat energy utilization rate can be improved. The preparation method disclosed by the invention has the advantages of good batch production effect, stable product performance and long shelf life.

Description

Technical Field

[0001] The invention belongs to the technical field of boiler water treatment, and in particular relates to a water quality stabilizer suitable for water treatment in medium-pressure, high-pressure and ultra-high-pressure boilers. Background Art

[0002] In modern industrial society, boilers are the core equipment of industrial foundation. They convert chemical energy into thermal energy by burning fuel or using waste heat to generate steam, providing the necessary heat and power source for industrial production. Boilers can be divided into low pressure (<2.5MPa), medium pressure (2.5-5.3MPa), high pressure (5.3-13.7MPa), ultra-high pressure (13.7-16.7MPa), subcritical (16.7-22.1MPa) and supercritical (≥22.1) according to their outlet steam pressure range. Among them, medium pressure boilers are usually used in small thermal power plants or industrial fields (such as steel plants, chemical plants), high pressure boilers are usually used in large thermal power plants or self-provided power plants of industrial and mining enterprises, and ultra-high pressure or subcritical boilers are usually used in large power systems.

[0003] In the long-term operation of the boiler, with water or water vapor as the heat transfer medium, scaling and corrosion will inevitably occur in the boiler system, which will cause great harm to the safe operation of the boiler. In serious cases, it may even cause pipe bursts, equipment shutdowns and various production safety accidents. In order to avoid accidents and ensure the efficiency and reliability of the boiler operation, the water in the boiler needs to be treated.

[0004] In the prior art, ammonia, hydrazine and trisodium phosphate are usually used to treat boiler water (such as a chemical control method during the operation of a nuclear power plant auxiliary boiler disclosed in announcement number CN112331374B). The specific mechanism is:

[0005] About ammonia: The boiler water treatment process uses ammonia to add ammonia to ensure the pH value of the feed water, ensuring a weak alkaline environment (8.8-9.3) for the feed water treatment, and adding hydrazine to eliminate dissolved oxygen in the feed water to avoid corrosion of the boiler system. However, the pH value of the boiler feed water is adjusted by adding ammonia. Ammonia has a strong odor, is corrosive and toxic, and has serious occupational hazards. Inhalation of ammonia can cause severe irritation to the respiratory tract, contact with the skin can cause skin corrosion, and can also cause severe irritation to the eyes, mouth and nose. The reaction between ammonia and copper can cause corrosion and dissolution of copper. Copper reacts with oxygen, ammonia and water to generate tetraammine copper ions and hydroxide ions, forming an alkaline tetraammine copper solution (reaction formula: 2Cu+O2+8NH3+2H2O=2[Cu(NH3)4]2++4OH-).

[0006] About hydrazine: Hydrazine is added to boiler feed water as a chemical deoxygenation supplement to ensure that the dissolved oxygen in the feed water is qualified and to avoid corrosion of economizers, steam drums, risers, water walls, superheaters, reheaters, etc. Hydrazine is a colorless, transparent, fuming liquid, a Class 2A carcinogen, with strong reducing properties and explosion hazard, and is a hazardous chemical. It is difficult to use and manage, and is very harmful to the human body.

[0007] About trisodium phosphate: In the boiler drum, trisodium phosphate is directly added to the boiler water to produce a weak alkaline environment (boiler water pH value 9.0-11.0) to avoid corrosion in the furnace, and the phosphate generated by hydrolysis can react with calcium and magnesium ions to produce water slag, which can be discharged from the boiler system through a large amount of sewage. As a traditional process for in-furnace treatment of the current boiler system, this process has general scale and corrosion inhibition effects and has technical limitations. The boiler controls corrosion and scaling problems by adding trisodium phosphate in the furnace. The phosphate process has alleviated the corrosion and scaling problems of the boiler to a certain extent, but from the long-term practical results, the control effect is general. The boiler using the phosphate process still has many scaling and corrosion problems, and steam entrainment, the sodium ions and phosphates existing in it are easy to enter the superheater, reheater and turbine blades with the steam, causing pipe bursts and a significant decrease in the operating efficiency of the turbine. The phosphate process has serious hysteresis, and the manual control delay is long, resulting in frequent fluctuations in boiler water and steam indicators, which are difficult to control smoothly; it increases the workload of operators and places strict requirements on employees' sense of responsibility and technical level. Trisodium phosphate is an inorganic salt, which causes the conductivity of boiler water to increase significantly. It is necessary to control the quality of water vapor through a large amount of sewage discharge, resulting in a large amount of desalted water waste and heat energy loss.

[0008] Therefore, when the existing phosphate treatment process is adopted, the quality of water vapor such as boiler water and steam fluctuates greatly, and the control is seriously delayed. It is highly dependent on the performance, skill level and sense of responsibility of on-site chemical water testing personnel, and it is difficult to achieve precise control. In addition, the comprehensive discharge volume of the boiler system is high, and the heat energy and water loss are serious, resulting in a lot of waste.

[0009] In summary, the three reagents of ammonia water, hydrazine and trisodium phosphate used in the prior art to treat boiler water have the above-mentioned shortcomings.

[0010] Based on this, the applicant considered designing a water quality stabilizer to solve the above-mentioned shortcomings. Summary of the invention

[0011] In view of the above-mentioned deficiencies in the prior art, the technical problems to be solved by the present invention are:

[0012] How to provide a water quality stabilizer suitable for medium-pressure, high-pressure and ultra-high-pressure boiler furnace water treatment, which can replace the three traditional agents of ammonia, hydrazine and trisodium phosphate, effectively increase the pH value of feed water, reduce the dissolved oxygen in feed water, stabilize water quality, help reduce boiler sewage discharge, reduce heat loss and water waste, and improve boiler thermal energy utilization.

[0013] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0014] A water quality stabilizer suitable for in-furnace treatment of medium-pressure, high-pressure or ultra-high-pressure boilers, characterized in that the water quality stabilizer comprises 25-50 parts by weight of polyorganic amines, 2-10 parts by weight of organic deoxidizers, 1-5 parts by weight of high molecular polymers, 0.5-2 parts by weight of silt regulators and 20-70 parts by weight of pure water.

[0015] Furthermore, the polyvalent organic amines are prepared by mixing 2-4 parts by weight of a film-forming amine, 15-35 parts by weight of a basic amine and 2-4 parts by weight of a volatile amine.

[0016] Furthermore, the film-forming amine is composed of at least one or more C8-C24 long-chain fatty alkylamine derivatives, and has 1-3 amine groups.

[0017] Furthermore, the alkaline amine includes one or more of morpholine, methylamine, dimethylamine, ethylenediamine, trimethylamine, diethylamine, triethylamine, ethylenediamine, triethanolamine, diethanolamine, ethanolamine, diethylaminoethanol and choline.

[0018] Furthermore, the volatile amine includes one or more of cyclohexylamine, cyclohexylamine carbonate, diethylenetriamine, isopentylamine, cyclopentylamine, cyclohexylamine, dicyclohexylamine and 1,6-hexanediamine.

[0019] Further, the organic deoxidizer includes one or more of dimethyl ketone oxime (acetone oxime), butyraldehyde oxime, acetaldehyde oxime, diethylhydroxylamine, isopropylhydroxylamine, isoascorbic acid (sodium), hydroquinone, carbohydrazides and their derivatives, N,N,N',N'-tetrasubstituted phenylenediamine, dihydroxyacetone and aminoheterocyclic compounds (1-aminopyrrolidine, 1-amino-4-methylpiperazine, aminomorpholine, 1-aminopiperidine, etc.).

[0020] Furthermore, the components of the high molecular polymer include organic phosphonates, polycarboxylates and sulfonic acids.

[0021] Furthermore, the organic phosphonates include one or more of pentasodium aminotrimethylenephosphonate (ATMP·Na5), tetrasodium hydroxyethylidene diphosphonate (HEDP·Na4), potassium hydroxyethylidene diphosphonate (HEDP·K2), pentasodium ethylenediaminetetramethylenephosphonate (EDTMP·Na5), pentasodium diethylenetriaminepentamethylidenephosphonate (DTPMP·Na5), tetrasodium 2-phosphonobutane-1,2,4-tricarboxylate (PBTCA·Na4), potassium hexamethylenediaminetetramethylenephosphonate (HDTMPA·K6) and sodium bis(1,6-hexamethylenetriaminepentamethylidenephosphonate) (BHMTPH·PN(Na2)).

[0022] Furthermore, the polycarboxylic acid includes one or more of sodium polyepoxysuccinate (PESA), sodium polyaspartate (PASP), hydrolyzed polymaleic anhydride (HPMA) and maleic acid-acrylic acid copolymer (MA / AA).

[0023] Furthermore, the sulfonic acid includes one or more of acrylic acid-2-acrylamide-2-methylpropanesulfonic acid copolymer (AA / AMPS), acrylic acid-sulfonic acid-amide copolymer, and carboxylic acid-sulfonic acid-acrylate terpolymer (AA-AMPS-HPA).

[0024] The water quality stabilizer of the present invention, which is suitable for treatment in a medium-pressure, high-pressure or ultra-high-pressure boiler furnace, has the following beneficial technical effects:

[0025] 1. It can be a chemical that replaces the three chemicals of ammonia, hydrazine and trisodium phosphate added in traditional boiler water treatment. It can control the pH value of boiler feed water and reduce the dissolved oxygen in boiler feed water. It also has multiple functions such as film formation, corrosion inhibition, deoxidation, passivation, scale inhibition, scale dissolution, dispersion, chelation, and water quality stabilization. It can stabilize the boiler water quality, control the occurrence of scaling and corrosion in the furnace, and reduce the sewage discharge rate, heat energy loss and water waste, which can help improve the steam quality.

[0026] 2. The film-forming amines used in this water stabilizer refer to long-chain fatty alkylamine derivatives composed of C8 to C24 (with 1 to 3 amine groups). Film-forming amines can form a continuous monomolecular adsorption film on the metal surface, with one side being hydrophobic (metal-philic group) and the other side being hydrophilic. As a barrier to prevent corrosion between water and metal, they can effectively promote the formation of a dense, continuous, stable, and tough metal oxide protective film on the metal surface. (See Figure 2 As shown in the figure, there are more amino groups in contact with the metal surface, which leads to higher bonding efficiency and stronger film adhesion; the molecular carbon chain is more parallel to the metal surface, making the film formation more stable; due to the extremely tight molecular arrangement, the corrosive components in the boiler water cannot contact the bare metal, thus playing a better protective role.

[0027] 3. Film-forming amines can form a thin film on the metal surface to block corrosive substances such as oxygen, carbon dioxide and carbonic acid. The hydrophobic alkyl group makes the metal surface non-wettable by water. Once the protective film is formed, it can maintain a good metal film finish. The basic agent is subjected to shock doses that are reduced to the normal required level and will not cause damage to the metal surface.

[0028] 4. The strong surface affinity of film-forming amines can lead to the gradual removal of attached scale. At the same time, the film-forming amines interact with hydroxylated iron oxide to form surface complexes, which can better promote film formation and achieve the purpose of enhanced passivation and corrosion inhibition.

[0029] 5. The volatile alkaline amines in polyamine organic amines can enter the condensing system with the steam, increase the pH value of the steam condensate, create a weak alkaline environment, and better protect the condensing system.

[0030] 6. After the pH value of steam condensate increases, it will be recycled to the water supply system and enter the water supply system together with fresh desalted water. The pH value of the water supply will also increase accordingly, achieving the purpose of controlling the pH value of the water supply. No more ammonia water is needed to maintain the pH value of the water supply. This can reduce the process of adjusting the pH value of the water supply, reduce the workload of the operator, or reduce the deployment investment cost of related pH value control equipment.

[0031] 7. Organic deoxidizers can react deeply with dissolved oxygen in water. The reaction is as follows:

[0032] 2R1-COHCOH-R2+02→2R1-COCO-R2+2H20 deoxygenation

[0033] 2(R1)2CHNHOH+02→2(R1)2C=NOH+2H20 Deep deoxygenation (first step)

[0034] 2(R1)2C=NOH+02→2(R1)2C=O+N2O+H20 (Step 2)

[0035] Organic deoxidizers can react with metal oxides to effectively promote the formation of metal passivation films. The reaction is as follows:

[0036] R1-COHCOH-R2+3Fe203→R1-COCO-R2+2Fe304+H20 passivation

[0037] (R1)2CHNHOH+3Fe2O3→R1-COCO-R2+2Fe3O4+H20 passivation

[0038] Organic deoxidizers can effectively reduce the dissolved oxygen in boiler water, steam, and steam condensate. After the recovered steam condensate contains volatile deoxidizer, it can effectively reduce the dissolved oxygen in the feed water after being recycled into the feed water system, thereby effectively reducing the dissolved oxygen in the feed water, ensuring that the dissolved oxygen index of the feed water meets the standard, and avoiding corrosion in the boiler system.

[0039] 8. High molecular polymers have strong functions of scale inhibition, scale dissolution, dispersion, chelation, rust removal and corrosion inhibition. They can slowly peel off old scale and better control corrosion and scaling problems in the furnace.

[0040] 9. The sludge regulator and other auxiliary agents are mainly sodium polyacrylate (PAAS), which mainly flocculates the chelated macromolecular particles into agglomerates quickly, settles quickly, and then discharges them from the furnace through a small amount of fixed discharge.

[0041] 10. Improve boiler water parameters and steam quality, and greatly improve the water and steam quality of the boiler system. The pH value of feed water is stable, the dissolved oxygen in feed water is reduced, the conductivity of boiler water is greatly reduced, the pH value of boiler water is stable, the sodium and silicon in steam are reduced, and the steam cleanliness is improved. It completely eliminates the problems of steam entrainment of sodium ions and phosphates caused by the phosphate process, improves the condition of the boiler drum and heating system, and prevents boiler corrosion, scaling, steam entrainment and salt formation.

[0042] 11. Boiler water stabilizer has multiple functions such as cleaning, scale dissolving, rust removal, deoxidation, passivation, corrosion inhibition, film protection, scale inhibition, scale dissolving, solubilization, pH stabilization, and protection of condensate pipelines. Organic components can reduce electrical conductivity and provide better anti-corrosion and scale inhibition. At the same time, some volatile agents can enter the entire condensate pipeline to protect the entire system, completely avoiding the salt problem caused by steam entrainment.

[0043] 12. Boiler continuous discharge (the boiler continuously discharges sewage during operation) can be closed to the minimum state, and fixed discharge (draining sewage once before the boiler is shut down and cooled) can be adjusted from once per shift or once per day to once every 3 to 7 days. The boiler sewage discharge volume is greatly reduced, and the boiler sewage discharge rate can be reduced to between 0.2% and 0.5%, avoiding the waste of a large amount of high-temperature steam and hot water, effectively recovering heat energy, thereby increasing the boiler steam production rate and improving the utilization rate of heat energy.

[0044] 13. The traditional phosphate dosing process adopts intermittent dosing. This water quality stabilizer dosing method suitable for medium-pressure, high-pressure and ultra-high-pressure boilers adopts continuous dosing. It only needs to ensure that the dissolving tank is full of the agent. The control method is more convenient and simple, reducing the difficulty of management.

[0045] The agent does not contain phosphate, so there is no need to test phosphate. The dosing can be controlled based on the conductivity and pH value of the boiler water. The feedback is more timely, which reduces the labor intensity and operation difficulty of workers. It reduces phosphorus discharge and reduces the cost of environmental protection treatment of sewage discharge. The boiler dosing can be adjusted from ammonia water, hydrazine and phosphate to one dosing. The boiler water quality stabilizer can achieve multiple functions. Dosing is more convenient.

[0046] 14. Boiler water quality stabilizer adopts all organic ingredients such as non-toxic, non-corrosive, and non-carcinogenic. It is not a hazardous chemical, which reduces the occupational hazards of employees and makes the storage and use of the agent safer and more convenient.

[0047] The preparation method of the water quality stabilizer is characterized by comprising the following steps:

[0048] S1. Pure water accounting for two-fifths to four-fifths of the total weight is thermally deoxygenated by a deaerator and is kept in reserve, with the temperature of the pure water maintained at 50-60°C;

[0049] S2, mixing the film-forming amine with pure water, entering an emulsifying agitator, maintaining the temperature at 50-60° C. in the emulsifying agitator, and adding volatile amine and alkaline amine after sufficient stirring to obtain a polyvalent organic amine raw material;

[0050] S3, transferring the polyamine organic amine raw material to a high temperature stirring tank, maintaining the temperature of the high temperature stirring tank at 70-85°C, then adding an organic deoxidizer, and mixing thoroughly to obtain an intermediate raw material;

[0051] S4, transferring the intermediate raw materials to a stirring tank, adding a high molecular weight polymer into the stirring tank, adding the remaining amount of pure water, and stirring and mixing thoroughly;

[0052] S5. Let stand in the stirring tank for 30 minutes and cool to room temperature.

[0053] The preparation method of the water quality stabilizer in the present invention has the advantages of being easy to implement, highly controllable in the production and processing process, good in batch production effect, and the prepared water quality stabilizer product has stable performance, good versatility and a long shelf life (starting from 2 years, solving the pain point of performance degradation due to long-term storage). BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 A schematic diagram of the molecular structure of a film-forming amine in the present invention

[0055] Figure 2 for Figure 1 Schematic diagram of the formation of films of polyamine organic amines on metal surfaces

[0056] Figure 3 for Figure 1 Schematic diagram of the principle of the formation of a protective film on the metal surface by a medium-film-forming amine

[0057] Figure 4aThis is a microscopic enlarged picture of boiler scale after the existing phosphate process (the larger the scale diameter, the easier it is to scale) Figure 4b This is a microscopic enlarged picture of the boiler scale after being treated with the water quality stabilizer for this application (the scale diameter is finer and it is difficult to scale) Figure 5a The pH trend chart of boiler water after using the water quality stabilizer of this application and using trisodium phosphate to treat the boiler

[0058] Figure 5b The conductivity trend chart of boiler water after using the water quality stabilizer of this application and using trisodium phosphate to treat the boiler Figure 5c The trend chart of phosphate in boiler water after using the water quality stabilizer of this application and using trisodium phosphate to treat the boiler Figure 5d The trend chart of steam sodium after using the water quality stabilizer of this application and using trisodium phosphate to treat the boiler

[0059] Figure 5e The trend chart of steam silicon after using the water quality stabilizer of this application and using trisodium phosphate to treat the boiler DETAILED DESCRIPTION

[0060] The present invention is further described in detail below in conjunction with multiple groups of embodiments.

[0061] Table 1 List of water stabilizers of various components

[0062]

[0063] During implementation, the pure water may be deionized water (with a conductivity lower than 5 μS / cm) or deionized water (with a conductivity lower than 0.1 μS / cm).

[0064] During implementation, the film-forming amine may be one or both of octadecenylaminotrimethyleneamine and N-octadecylamine.

[0065] During implementation, the components of the polyvalent organic amines include 2-4 parts by weight of film-forming amines, 15-35 parts by weight of alkaline amines and 2-4 parts by weight of volatile amines. Preferably, the weight ratio of film-forming amines to volatile amines in the water stabilizer is 1:1, so that the weight proportion of film-forming amines and volatile amines in the polyvalent organic amines is relatively small. This has the advantage that since film-forming amines are mainly used to form films on metal surfaces and have low solubility, in polyvalent organic amines or water stabilizers, if the proportion of film-forming amines is greater than the above optimal proportion, it is easy to cause stratification, thereby affecting the product quality (homogenization), shelf life and performance of the water stabilizer.

[0066] During implementation, the volatile amines in the polyvalent organic amines adopt the above low-concentration preferred ratio, which can more accurately adjust the pH of the feed water and avoid excessive alkalinity of the feed water due to excessive concentration.

[0067] The preparation method of the water quality stabilizer suitable for medium-pressure, high-pressure or ultra-high-pressure boiler furnace treatment in the above-mentioned embodiments of various component ratios comprises the following steps:

[0068] S1. Pure water accounting for two-fifths to four-fifths of the total weight is thermally deoxygenated by a deaerator and is kept in reserve, with the temperature of the pure water maintained at 50-60°C;

[0069] S2, mixing the film-forming amine with pure water, entering an emulsifying agitator, maintaining the temperature at 50-60° C. in the emulsifying agitator, and adding volatile amine and alkaline amine after sufficient stirring to obtain a polyvalent organic amine raw material;

[0070] S3, transferring the polyamine organic amine raw material to a high temperature stirring tank, maintaining the temperature of the high temperature stirring tank at 70-85°C, then adding an organic deoxidizer, and mixing thoroughly to obtain an intermediate raw material;

[0071] S4, transferring the intermediate raw materials to a stirring tank, adding a high molecular weight polymer into the stirring tank, adding the remaining amount of pure water, and stirring and mixing thoroughly;

[0072] S5. Let stand in the stirring tank for 30 minutes and cool to room temperature.

[0073] After the preparation is completed, samples can be taken for testing (simulating and maintaining the environmental parameters in a variable temperature and pressure test instrument (such as an electrically heated high-pressure test kettle) to verify the performance of the agent under the environmental parameters and ensure its adaptability and reliability in use); after passing the test, the agent can be packaged and sealed.

[0074] In the above step S4, a low temperature stirring tank (controlled temperature of 5±2°C) is preferably used. The low temperature can reduce the volatilization of the solvent, and at the same time, the mass transfer efficiency is enhanced by stirring, which promotes the uniform dispersion of the polymer. The subsequent shelf life of the product can be extended to 2 years.

[0075] The characteristic index table of the water quality stabilizer suitable for medium-pressure, high-pressure or ultra-high-pressure boiler furnace treatment prepared by the above Examples 1-16:

[0076] Table 2 Characteristics of water stabilizer

[0077] characteristic index Appearance Colorless or light yellow transparent liquid Density(20℃) <![CDATA[1.0±0.05g / cm 3 ]]> pH(25℃) 13.0±1.0 Water Solubility Miscible in any ratio Conductivity 3.0~20.0ms / cm

[0078] During implementation, the sludge regulating agent includes sodium polyacrylate (PAAS) or polyethylene glycol. The sludge regulating agent rapidly flocculates the chelated macromolecular particles into agglomerates, rapidly settles, and then is discharged from the furnace through a small amount of fixed discharge.

[0079] Specific application cases of the water quality stabilizer of the present invention:

[0080] 1. On-site conditions before the application of the water quality stabilizer:

[0081] A company has a high-pressure boiler on site. The original design evaporation capacity is 130t / h. After expansion, the boiler evaporation capacity is 150t / h, and the actual evaporation capacity is about 150t / h. The boiler has a designed steam pressure of 9.8MPa and a designed steam temperature of 540℃. The steam generated is mainly used for production and power generation. The boiler was originally treated with phosphate process, and the following problems occurred during operation:

[0082] (1) Ammonia water was used to adjust the pH value of the feed water, and thermal deoxygenation was combined with acetone oxime chemical deoxygenation. However, red rust corrosion was observed in the steam drum during maintenance.

[0083] (2) Using the traditional phosphate furnace dosing process, the phosphate concentration is controlled at 2-10 mg / L. The phosphate concentration fluctuates greatly, and parameters such as pH value and conductivity are unstable.

[0084] (3) The main sources of boiler raw water are tap water and deep well water. When tap water is used as raw water, the conductivity of boiler water is 40-80μs / cm. When deep well water is used as raw water in winter, the water quality of deep well water is deviated and the conductivity of boiler water is above 100μs / cm.

[0085] (4) The water supply is treated by "primary reverse osmosis + yin-yang mixed bed".

[0086] (5) The content of sodium ions and silicon dioxide in steam exceeded the standard at certain times, affecting the stability of steam quality;

[0087] (6) The system’s sewage discharge rate is significantly too high, resulting in a large loss of desalted water and a large amount of heat waste;

[0088] (7) The various water parameters of the boiler system cannot meet the relevant requirements of "GB / T 12145-2016 Water and Steam Quality Standard for Thermal Power Generators and Steam Power Equipment".

[0089] 2. Application of the water quality stabilizer involved in this application:

[0090] (1) Preparation

[0091] Stop adding trisodium phosphate, empty all the reagents in the dissolving tank, and inject deionized water to rinse the tank several times to ensure that there is no sediment, no impurities, etc. Determine the dissolving ratio and the range of the dosing pump according to the preliminary investigation. The dissolving tank is about 1000L, and the flow range of the dosing pump is adjusted to about 15%.

[0092] (2) Initial dosing

[0093] For initial dosing, add 1 barrel (25kg / barrel) of dosing solution into the dosing tank, and then inject deionized water into the tank until the dosing tank is full.

[0094] (3) Early stage of fluctuation and adjustment (about 5-6 days)

[0095] During the first three days of commissioning, the water quality stabilizer involved in this application has the ability to clean, remove and dissolve scale, and the parameters such as the conductivity, sodium, phosphate and steam conductivity of the boiler water increased significantly. The continuous discharge was opened in 1 to 3 days to discharge a large amount of impurities dissolved in the boiler. The test data of the boiler water gradually improved after 3 to 5 days, and the continuous discharge was gradually closed to reduce the frequency of fixed discharge. All data can meet and exceed the relevant standard requirements of GB / T 12145-2016 Water and Steam Quality of Thermal Power Generator Sets and Steam Power Equipment. According to the stabilized data, the dosage and discharge amount were adjusted and compared again to ensure the optimal dosage and minimum discharge amount of the boiler system.

[0096] (4) Optimization and stabilization phase

[0097] After the initial fluctuation and adjustment phase, the continuous discharge has been closed to the minimum state (a little bit after closing), and the fixed discharge frequency has been adjusted from once per shift to once every three days, which has greatly reduced the discharge of pollutants. The dosage has also been gradually adjusted to about 5.0ppm (the average dosage is about 18L / day, the dosage concentration is about 5.0mg / L; the annual usage is about 6.0t / year), and all data indicators have stabilized and improved, entering a completely stable stage.

[0098] Table 3 Comparison test data table

[0099]

[0100] The units of each test item in Table 1 are: conductivity is μs / cm, phosphate concentration is mg / L, and steam sodium and steam silicon are both ug / kg. For specific trend chart comparison, see Figure 5a-5e .

[0101] From the above, it can be seen that the water quality stabilizer of the present application has the following advantages:

[0102] The pH value of boiler water can still be controlled between 9.2 and 9.7, and the pH value of boiler water remains relatively stable. The pH value of boiler water can reach and exceed the relevant standard requirements of "GB / T 12145-2016 Water and Steam Quality for Thermal Power Generator Sets and Steam Power Equipment" (9.0-10.5).

[0103] The conductivity has dropped significantly, basically maintained between 25 and 40μs / cm, and the boiler water has good stability. The conductivity of boiler water is significantly better than the standard requirements of "GB / T 12145-2016 Water and Steam Quality for Thermal Power Generators and Steam Power Equipment" (high-pressure boilers <50μs / cm).

[0104] The phosphate in the boiler water is close to zero (the presence of trace phosphate may be affected by the instrument or residual phosphate). The use of phosphorus-free reagents is green and environmentally friendly, reducing the environmental load. Workers no longer need to test phosphate, which reduces the labor intensity of employees and makes the control more portable.

[0105] The sodium ion in steam is less than 5.0μg / kg, which meets the requirements of GB / T 12145-2016 Steam Quality for Thermal Power Generators and Steam Power Equipment. The boiler water concentration is higher than that of the phosphate process, and the control effect of steam sodium is better than that of the phosphate process. Compared with trisodium phosphate, it contains less sodium ions, so the performance of steam sodium ions will be better in long-term operation.

[0106] The silicon ions in steam are all less than 5μg / kg, which meets the requirements of the standard "GB / T 12145-2016 Water Steam Quality for Thermal Power Generators and Steam Power Equipment" (15μg / kg). The steam silicon control effect is better than that of the phosphate process.

[0107] The boiler energy saving can reach more than 3.0t / h (high-temperature steam-water mixture), and the energy saving effect is obvious. Specifically: by comparing the data before and after commissioning, the steam-water ratio (ratio of water supply to steam) decreased by 0.023, that is, the sewage discharge rate decreased by 2.30%. According to the average evaporation of 148.73t / h, the energy saving reached 3.42t / h (high-temperature steam-water mixture). By comparing the data before commissioning and before investigation, the steam-water ratio (ratio of water supply to steam) decreased by 0.021, that is, the sewage discharge rate decreased by 2.10%. According to the average evaporation of 149.12t / h, the energy saving reached 3.13t / h (high-temperature steam-water mixture). Energy saving benefits calculated based on energy saving of 3.0t / h (high-temperature steam-water mixture): It is estimated that the energy saving can reach 2.2848 million yuan / year (energy saving benefit + water saving benefit), and the cost reduction and efficiency improvement effect is obvious.

[0108] The above are only preferred implementations of the present invention. It should be pointed out that a number of modifications and improved technical solutions made by those skilled in the art without departing from the technical solution should also be deemed to fall within the scope of protection required by the claims.

Claims

1. Water quality stabilizer suitable for medium pressure, high pressure or ultra-high pressure boiler furnace treatment, characterized by: The water quality stabilizer comprises 25-50 parts by weight of polyvalent organic amines, 2-10 parts by weight of organic deoxidizers, 1-5 parts by weight of high molecular polymers, 0.5-2 parts by weight of silt regulators and 20-70 parts by weight of pure water.

2. The water quality stabilizer suitable for in-furnace treatment of medium-pressure, high-pressure or ultra-high-pressure boilers according to claim 1, characterized in that: The polyvalent organic amines are prepared by mixing 2-4 parts by weight of a film-forming amine, 15-35 parts by weight of a basic amine and 2-4 parts by weight of a volatile amine.

3. The water quality stabilizer suitable for in-furnace treatment of medium-pressure, high-pressure or ultra-high-pressure boilers according to claim 2, characterized in that: The film-forming amine is composed of at least one or more long-chain fatty alkylamine derivatives composed of C8-C24 and has 1-3 amine groups.

4. The water quality stabilizer suitable for in-furnace treatment of medium-pressure, high-pressure or ultra-high-pressure boilers according to claim 2, characterized in that: The basic amine includes one or more of morpholine, methylamine, dimethylamine, ethylenediamine, trimethylamine, diethylamine, triethylamine, ethylenediamine, triethanolamine, diethanolamine, ethanolamine, diethylaminoethanol and choline.

5. The water quality stabilizer suitable for in-furnace treatment of medium-pressure, high-pressure or ultra-high-pressure boilers according to claim 2, characterized in that: The volatile amines include one or more of cyclohexylamine, cyclohexylamine carbonate, diethylenetriamine, isopentylamine, cyclopentylamine, cyclohexylamine, dicyclohexylamine and 1,6-hexanediamine.

6. The water quality stabilizer suitable for in-furnace treatment of medium-pressure, high-pressure or ultra-high-pressure boilers according to claim 1, characterized in that: The organic oxygen scavenger includes one or more of dimethyl ketone oxime (acetone oxime), butyraldehyde oxime, acetaldehyde oxime, diethylhydroxylamine, isopropylhydroxylamine, isoascorbic acid (sodium), hydroquinone, carbohydrazides and their derivatives, N,N,N',N'-tetrasubstituted phenylenediamine, dihydroxyacetone and aminoheterocyclic compounds (1-aminopyrrolidine, 1-amino-4-methylpiperazine, aminomorpholine, 1-aminopiperidine, etc.).

7. The water quality stabilizer suitable for in-furnace treatment of medium-pressure, high-pressure or ultra-high-pressure boilers according to claim 1, characterized in that: The components of the high molecular polymer include organic phosphonates, polycarboxylates and sulfonic acids in a weight ratio of 2:2:

1.

8. The water quality stabilizer suitable for in-furnace treatment of medium-pressure, high-pressure or ultra-high-pressure boilers according to claim 7, characterized in that: The organic phosphonates include one or more of pentasodium aminotrimethylenephosphonate (ATMP·Na5), tetrasodium hydroxyethylidene diphosphonate (HEDP·Na4), potassium hydroxyethylidene diphosphonate (HEDP·K2), pentasodium ethylenediaminetetramethylenephosphonate (EDTMP·Na5), pentasodium diethylenetriaminepentamethylidenephosphonate (DTPMP·Na5), tetrasodium 2-phosphonobutane-1,2,4-tricarboxylate (PBTCA·Na4), potassium hexamethylenediaminetetramethylenephosphonate (HDTMPA·K6) and sodium bis(1,6-hexamethylenetriaminepentamethylidenephosphonate) (BHMTPH·PN(Na2)).

9. The water quality stabilizer suitable for in-furnace treatment of medium-pressure, high-pressure or ultra-high-pressure boilers according to claim 7, characterized in that: The polycarboxylates include one or more of sodium polyepoxysuccinate (PESA), sodium polyaspartate (PASP), hydrolyzed polymaleic anhydride (HPMA) and maleic acid-acrylic acid copolymer (MA / AA).

10. The method for preparing a water quality stabilizer according to any one of claims 1 to 9, characterized in that: The following steps are involved: S1. Pure water accounting for two-fifths to four-fifths of the total weight is thermally deoxygenated by a deaerator and is kept in reserve, with the temperature of the pure water maintained at 50-60°C; S2, mixing the film-forming amine with pure water, entering an emulsifying agitator, maintaining the temperature at 50-60° C. in the emulsifying agitator, and adding volatile amine and alkaline amine after sufficient stirring to obtain a polyvalent organic amine raw material; S3, transferring the polyamine organic amine raw material to a high temperature stirring tank, maintaining the temperature of the high temperature stirring tank at 70-85°C, then adding an organic deoxidizer, and mixing thoroughly to obtain an intermediate raw material; S4, transferring the intermediate raw materials to a stirring tank, adding a high molecular weight polymer into the stirring tank, adding the remaining amount of pure water, and stirring and mixing thoroughly; S5. Let stand in the stirring tank for 30 minutes and cool to room temperature.

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