Acid compounds are one of the main impurities in natural water, and they have various forms in water, making them a relatively complex compound. The different forms of silicate compounds in water are closely related to the pH value of the water. When pH< At 7 o'clock, there are actually only molecules of silica in the water, and there are no silicate ions present. So, when the pH value is low (in acidic solutions), the amount of colloidal silica in water increases significantly; When the pH value is> At 7 o'clock, both H2SiO3 and HSiO3- were present in the water; When pH=11, HSiO3- is the main component in water; SiO32- ions only appear in highly alkaline water (pH> 11).

What is the relationship between the form of carbonate compounds in water and the pH value of water?

Answer: Carbonate compounds have several different forms of existence in water: gases dissolved in water (known as free CO2); Molecular state carbonate H2CO3; Bicarbonate HCO3- and carbonate CO32-. There is a balance relationship between these four:

CO2+H2O+H2CO3

H2CO3 H+DecaHCO3-

HCO3- H+Ten CO32-

If these equilibrium equations are connected, they can be written as follows:

CO2 Ten H2O H2CO3 H+Ten HCO3 2H+Ten CO32-

In the above series of equilibria, the equilibrium between CO2 and H2CO3 actually strongly tends to generate CO2, and the amount of water in the state of H2CO3 is very small (usually less than 1%), so the process of generating H2CO3 can be omitted,

Based on the above situation, it can be seen that [H+] plays a decisive role in the movement of equilibrium. The relationship between the relative values of CO2, HCO32-, and CO32- in water and the concentration of [H+] is shown in Figure 4-3. From Figures 4-3, it can be seen that:

(1) When pH< At 4 o'clock, there is only free CO2 in the water.

(2) When the pH value increases, the equilibrium shifts, [CO2] decreases, and [HCO3-] increases. When pH=8.3-8.4, more than 98% of carbonates exist in the form of HCO3-.

(3) When the pH value increases again (greater than 8.3), CO2 disappears, [HCO3-] decreases, and [CO32-] increases. When pH=12, carbonates in water almost completely exist in the form of CO32-.

What are the requirements for the pH value of water in coagulation treatment?

Answer: The pH value of water has a significant impact on the coagulation process. Different coagulants have different requirements for the pH value of water. Therefore, during coagulation treatment, it is necessary to strictly control the pH value of the water after adding coagulants.

The pH requirements for different coagulants are as follows:

(1) Aluminum salt. Aluminum salts in water undergo ionization and hydrolysis to form aluminum hydroxide colloids, and the pH value has two effects on this colloid.

One is that aluminum hydroxide is a zwitterionic hydroxide. When the pH value of water is below 5.5, aluminum hydroxide becomes alkaline and is dissolved. The reaction is as follows:

A1 (OH) 3+3H+A13+3H2O

The reaction result increases the residual aluminum content in the water.

When the pH value of water is higher than 7.5, aluminum hydroxide becomes acidic, and aluminum metaaluminate (AlO2-) appears in the water. The reaction is as follows:

AI (OH) 3 Deca OH -- AlO2 Deca 2H2O

The reaction result is an increase in residual aluminum in the water. Therefore, it cannot produce AI (OH) 2 flocs.

Secondly, when the pH value of water is between 5.5 and 8.8, aluminum hydroxide colloidal particles carry a positive charge. When the pH of water< At 5 o'clock, colloidal particles carry a negative charge; PH of water; At 8 o'clock, aluminum hydroxide dissolved.

Therefore, when the pH value of water is above 8.0 or below 5.0, it affects the formation of positively charged aluminum hydroxide colloids. Therefore, when using aluminum salts as coagulants, the pH value of water should be between 6.5 and 7.5.

(2) Iron salts. Iron salts ionize and hydrolyze in water to form positively charged iron hydroxide colloids, and the reaction is as follows:

4FeSC4+10H2O+O2 4Fe (OH) 3+4H2SO4

During this reaction process, Fe2+is present at pH> At 8.5, it is easily oxidized to Fe3+and forms Fe (OH) 3 colloids; When the pH value is low, the completion rate of the above reaction is slow.

Therefore, when using iron salts as coagulants for coagulation treatment, it is generally carried out together with lime treatment to maintain the pH value of the water between 8.5 and 10.

Due to differences in raw water quality and the use of different coagulants, a more realistic pH value should be determined through small-scale experiments.

What are the advantages of using polyaluminum as a coagulant?

Answer: Polyaluminum coagulants have the following advantages:

(1) Widely applicable. It has excellent coagulation effects on low turbidity water, high turbidity water, colored water, and certain industrial wastewater.

(2) Low dosage (calculated as Al2O3). For low turbidity water, its dosage is equivalent to 1/2 of aluminum sulfate; For high turbidity water, its dosage can be reduced to l/3 to l/4 of aluminum sulfate dosage.

(3) Easy to operate. After adding medication, the alkalinity of water decreases less, so the pH value of water also decreases less. The optimal pH range for coagulation is wide, and generally good results can be achieved from pH values of 7-8. The effect is still stable at low temperatures.

(4) The formation of flocs is fast. Due to the fast formation of flocculation by this agent, the volume of the clarification equipment can be reduced.

(5) Adding too much medication is not harmful and will not worsen the water quality.

Industrial water equipment, chemical water equipment, electronic water equipment

What is the non-uniformity coefficient of filter media? How does its size affect the operation of the filter?

Answer: The non-uniformity coefficient of the filter material is often expressed in KB. It refers to the ratio of the sieve aperture d80 that 80% (by mass) of the filter material can pass through to the sieve aperture d10 that 10% of the filter material can pass through

The uneven size of filter material particles has two adverse consequences: first, it is difficult to backwash because if the backwash intensity is too high, it will bring out small upper filter material particles; However, the backwash intensity is too low and the lower filter layer cannot be loosened. The second is the deterioration of the filtration situation, as small filter material particles are concentrated on the surface of the filter layer, causing suspended solids in the water to be intercepted and accumulated on the surface, forming a solid thick film. As a result, the head loss of the filter increases too quickly, and the filtration cycle is shortened.

What are the reasons for the difficulty in entering acid and alkali during the regeneration of the countercurrent regeneration ion exchanger? How to handle it?

Answer: The reason for the difficulty in entering acid and alkali during the regeneration of the countercurrent regeneration ion exchanger may be:

(l) The back pressure inside the ion exchanger is too high.

(2) The acid and alkali discharge devices are blocked.

(3) During the regeneration of the ion exchanger, the valve of the main body malfunctioned, and the regeneration liquid flowed into another exchanger.

(4) The injector for adding acid or alkali is damaged, or the inlet water pressure is too low and the outlet water pressure is too low.

The handling method is as follows:

(l) The ion exchanger maintains a certain back pressure (> 0.05MPa).

(2) When the acid and alkali discharge devices, as well as the acid and alkali injection nozzles, are damaged, they should be repaired and replaced in a timely manner.

(3) During the regeneration process, carefully check the opening and closing of the valves of each ion exchanger to prevent malfunction and failure to close.

(4) Regularly clean the nylon mesh sleeve of the acid and alkali discharge devices.

What are the main reasons for the decrease in working exchange capacity of ion exchangers during operation?

Answer: The working exchange capacity of ion exchangers decreases during operation, which may be due to the following reasons:

(1) When the new resin is put into operation, the working exchange capacity is relatively high. As the operating time increases, the working exchange capacity gradually decreases, and after a period of time, it can tend to stabilize.

(2) The surface of the exchange agent particles is contaminated by suspended solids, and even adhesive occurs.

(3) The raw water contains Fe2+, Fe3+, and Mn2+ions, causing poisoning of the exchange agent and darkening of the color.

(4) The dosage of regenerant is small, and the regeneration is not sufficient.

(5) The operating flow rate is too high.

(6) The salt content and hardness in the raw water during the dry season are too high.

(7) The resin layer is too low or the resin gradually decreases.

(8) The regenerant has poor quality and contains too many impurities.

(9) Blockage or damage to the water distribution device, drainage device, and regeneration liquid distribution device can cause flow deviation.

(10) When backwashing the ion exchanger, the backwashing strength is insufficient, and there is a lot of suspended solids accumulated in the resin layer, which bond with the resin to form mud balls or mud cakes, causing water to flow in a biased manner.

What is the reason for the failure of the counter current regeneration ion exchanger just after it is put into operation? How to handle it?

Answer: The reason for this phenomenon may be:

(1) There are problems with the regeneration operation, such as insufficient top pressure causing resin layers to be disordered.

(2) The regeneration liquid flow rate is too high, causing resin layer disorder.

(3) The thinning of the grease layer causes deviation of the regeneration fluid and top pressure fluid.

The handling method is as follows:

(1) Strengthen training in regeneration operations and master regeneration techniques correctly and proficiently.

(2) Adjust the regeneration liquid flow rate.

(3) Supplement the resin (or white ball) for the grease layer.

(4) Perform a major backwash.

What is the reason for the deterioration of effluent quality or significant reduction in operating cycle of the countercurrent regeneration ion exchanger? How to handle it?

Answer: The reason for this phenomenon may be:

(l) During the regeneration operation, replace or backwash water without using desalinated water (or softened water), causing the lower resin layer to be in a failed state. At the beginning of operation, there is continuous leakage of Na+(or hardness or HsiO3-).

(2) Excessive top pressure fluid pressure affects the amount of regeneration liquid entering.

The handling method is as follows:

(1) It is necessary to replace or backwash with desalinated water (or softened water).

(2) Adjust the top pressure device and check the top pressure gauge.

What are the reasons for the decrease in exchange capacity of floating bed ion exchangers? How to handle it?

Answer: The possible reason for this phenomenon in floating beds is:

(1) During regeneration, the resin at the top of the exchanger is exposed to the air, which affects the regeneration effect.

(2) When the water outlet device and the regeneration liquid inlet device are shared, the nylon mesh wrapped on the surface is partially blocked by broken resin, resulting in uneven distribution of regeneration liquid.

The handling method is as follows:

(l) Convert the regenerated waste liquid discharge pipe into an inverted U-shaped pipe.

(2) Remove the resin from the body, perform external backwashing, and inspect and repair the water outlet device.

What is the reason why the effluent resistance of the floating bed ion exchanger increases or even does not discharge water? How to handle it?

Answer: The possible reason for this phenomenon in floating beds is:

(1) The amount of broken resin and suspended solids in the resin layer increases.

(2) The nylon mesh of the water outlet device is damaged, and a large amount of resin accumulates in the resin trap, causing the water outlet to be blocked.

The handling method is as follows:

(1) Remove the resin from the body and perform external backwashing.

(2) Repair the water outlet device.

(3) Drain the resin from the trap.

What are the reasons for the failure of the floating bed ion exchanger just after it is regenerated and put into operation? How to handle it?

Answer: The possible reason for this phenomenon in floating beds is:

(1) When waking up, the water pressure is low, and the resin fails to form a bed, resulting in disorderly layers.

(2) The resin inside the exchanger was not naturally filled, the water cushion layer was too high, and the resin layer was disorderly.

The handling method is as follows:

(l) When starting, increase the wake up flow rate.

(2) Fill the resin and lower the height of the water cushion layer.

What are the advantages and disadvantages of using hydrochloric acid and sulfuric acid as regenerants for H-type ion exchangers?

Answer: The selection of rejuvenators is a crucial step in water treatment processes, as it directly affects the exchange capacity and effluent quality of the exchange resin.

Hydrochloric acid, as a regenerant for H-type ion exchangers, has the advantages of simple operation, good effluent quality, high exchange capacity of exchange resin, and no sediment generation during regeneration. This is because hydrochloric acid is a monobasic acid that is easy to ionize, and higher concentrations of regeneration solution can be used, resulting in good regeneration effect. Therefore, the exchange capacity of resin regenerated with hydrochloric acid can be increased by nearly twice compared to that regenerated with sulfuric acid, thereby prolonging the operating cycle of the exchanger, reducing the number of regenerations, and saving self consumption water. However, the price of hydrochloric acid is relatively high, and the cost of water production is higher than that of using sulfuric acid for regeneration. Acid storage equipment and its systems need to be corrosion-resistant and expensive, and measures to prevent acid mist pollution of the environment need to be taken.

The water production cost of regenerating H-type exchangers with sulfuric acid is lower, and concentrated sulfuric acid does not corrode steel. Therefore, ordinary steel containers can be used for storage, saving investment. However, sulfuric acid is a dicarboxylic acid with low activity and incomplete ionization, resulting in poor resin regeneration efficiency.

The exchange capacity of regenerated resin is only half of that of hydrochloric acid regeneration, with high self consumption of water and poor effluent quality. In addition, sulfuric acid regeneration resin is prone to generate calcium sulfate precipitation, so the regeneration operation is complicated (requiring step-by-step regeneration). To ensure equipment and personal safety, safety measures are in place to prevent water from flowing back into concentrated sulfuric acid equipment. The nozzle and mixing pipe of the acid injector should be made of high-temperature and corrosion-resistant materials, such as polytetrafluoroethylene and aluminum antimony alloy.

At present, most power plants use hydrochloric acid regeneration H-type ion exchangers, and based on technical and economic comparison, hydrochloric acid is more advantageous than sulfuric acid.

Why are anion exchangers placed after cation exchangers in the chemical desalination system of water?

Answer: In a chemical desalination system, the anion exchanger is placed after the cation exchanger for the following reasons:

(l) After the raw water is exchanged by a cation exchanger, the effluent becomes acidic, which is conducive to the exchange reaction of the anion exchanger and has a high silicon removal efficiency.

(2) The raw water directly enters the anion exchanger for exchange, which can produce insoluble compounds [such as Ca (OH) 2Mg (OH) 2, etc.], block the cross-linking pores inside the exchange resin, and reduce the exchange capacity of the anion exchange resin.

(3) There are a large amount of carbonates in the raw water, which can be decomposed into H2O and CO2 through cation exchange. After CO2 is removed by the decarbonization device, the total amount of anions entering the anion exchanger is reduced, thereby prolonging the operating cycle of the anion exchanger and reducing the consumption of regenerant.

(4) Anion exchange resin has poorer resistance to organic matter and other factors compared to cation exchange resin, so it is not suitable to directly introduce it into raw water.

How does the pH value of water affect the removal of silicon in anion exchangers?

Answer: The pH value of water has a direct impact on the silicon removal effect. The low pH value of water makes it easy to remove silicon, as silicon in the water exists in the form of silicic acid. The ion exchange reaction formula is as follows:

R-OH+H2SiO3-R-HsiO3+H2O

The high pH value of water makes it difficult to remove silicon, as silicon in water exists in the form of silicates, which can easily generate counter ion OH -. The higher the concentration of counter ion OH -, the greater its hindering effect on silicon removal. The reaction is as follows:

R-OH+NaHSiO3 R-HsiO3+NaOH

The reverse reaction rate of this reaction is much faster than the dry positive reaction rate, so the content of HsiO3- in water is higher.

What are the characteristics of a fixed bed countercurrent regeneration ion exchanger?

Answer: The major feature of a fixed bed countercurrent regeneration ion exchanger is that the direction of water flow during operation is opposite to the direction of regeneration liquid during regeneration, and it is generally operated in a clockwise direction for countercurrent regeneration. During countercurrent regeneration, fresh regeneration liquid first contacts the resin with less failure and flows upwards from the bottom of the exchanger, while low-quality regeneration liquid contacts the resin with more failure in the upper layer. According to the relationship between ion equilibrium in the solution, the regeneration solution can be well utilized in both the lower and upper parts, greatly improving the regeneration rate and economic efficiency of the resin. When running downstream, the treated water enters from the upper part of the exchanger and first comes into contact with resin with poor regeneration. As the water flows downwards, the amount of ions to be exchanged in the water gradually decreases, while the regeneration degree of the resin in contact increases. According to the equilibrium relationship of ion exchange, the higher the regeneration degree of resin in the protective layer, the higher the purity of the effluent. So, the regeneration degree of the exchange resin in the fixed bed countercurrent regeneration ion exchanger is high, the consumption of regeneration agent is low, and the effluent quality is also good.

What are the requirements for the concentration and flow rate of the regeneration solution during countercurrent regeneration of ion exchangers?

Answer: The selection of concentration is based on the regeneration effect, and the optimal concentration is obtained through adjustment experiments based on water quality and other conditions. When hydrochloric acid is used as a regenerant in general cation exchangers, the regeneration concentration is mostly within the range of 2% to 5%, but lower concentrations are also used; When regenerating anions, most of them use NaOH solutions between 0.5% and 2.5%, which have better effects.

The regeneration liquid flow rate during regeneration is generally within the range of 4-6 m/h. Excessive flow rate can cause disorderly layers and disrupt regeneration conditions; The flow rate is too small, the regeneration time is too long, and the effect may not be good.

What are the requirements for backwash water for countercurrent regeneration ion exchangers? Why?

Answer: The bottom exchange resin of the countercurrent regeneration ion exchanger is generally fully regenerated, and the resin regeneration degree is close to 100%. If water with high salt content is used for backwashing, the cation (or anion) in the backwash water is exchanged and adsorbed by the bottom resin, and these ions are replaced during operation, affecting the effluent quality. So it is better to use desalinated water (or softened water) for backwashing.

What issues should be noted during the storage and storage of ion exchange resins?

Answer: During the storage and storage process of ion exchange resin, attention should be paid to the following issues:

(l) When the resin is stored for a long time, it should be converted into a neutral salt type, washed with pure water, and then sealed.

(2) To prevent the resin from cracking during drying, it is better to soak it in boiled water. The water used to soak the resin needs to be changed frequently to avoid bacterial contamination.

(3) Once the resin is dehydrated, do not soak it in clean water. Soak it in saturated salt water and gradually dilute the salt solution to allow the resin to slowly expand. After recovery, soak the resin in boiled water.

(4) The storage temperature of the resin should not be too high, generally between 5 and 20 ℃, and should not exceed 40OC.

(5) During the storage process of resin, it is important to prevent contact with substances that can easily contaminate the resin, such as rust, strong oxidants, organic matter, and fats.

How to identify different ion exchange resins?

Answer: Take 2mL of resin and place it in a 30mL test tube. Add 5mL of 1mol/L HCl solution and shake for 1-2 minutes. Use a pipette to remove the clear liquid from the upper part. Repeat the operation 2-3 times, wash with distilled water 2-3 times, add 4-5mL of 10% CuSO4 solution, shake for 1 minute, discard the residual liquid from the upper part, and rinse 2-3 times with distilled water.

If the resin turns light green, add 2mL of 5moI/L NH3 · H2O and shake for 1 minute. If the resin turns dark blue, it is a strongly acidic resin; If it still remains light green, it is a weakly acidic resin.

If the resin does not change color after the above treatment, add 5mL of l mol/L NaOH solution and shake for 1 minute. Wash 2-3 times with distilled water, then add 5 drops of phenolphthalein solution and shake for 1 minute. If the resin is red, it is a strong alkaline resin. If the resin still does not change color, add l moI/L, 5mL HCI solution, shake for 1 minute, clean 2-3 times with distilled water, then add 5 drops of methyl red solution, shake for 1 minute. If the resin turns peach red, it is a weakly alkaline resin.

After the above treatment, if the resin still does not change color, it indicates that the resin has no ion exchange ability.

What are the factors that affect ion exchange rate?

Answer: The main factors affecting ion exchange rate are: ① the exchange groups of the resin; ② The degree of crosslinking of the resin; ③ The size of resin particles; ④ The concentration of the solution; ⑤ Water temperature; ⑥ Water flow velocity; ⑦ The inherent properties of the exchanged ions, etc.

What is the unit consumption of rejuvenators? What is the specific consumption of rejuvenators?

Answer: The number of grams of regenerant consumed to restore the exchange capacity of exchange agent l mol is called the unit consumption of regenerant. When using table salt for regeneration, it is called salt consumption. When using acid for regeneration, it is called acid consumption. When using alkali for regeneration, it is called alkali consumption.

During the operation of the ion exchanger, the higher the inlet water flow rate, the greater the working exchange capacity of the exchange agent, and the larger the periodic water production. ()

Answer:.

What is the working exchange capacity of an ion exchanger? What are the factors that affect the size of work exchange capacity?

Answer: During the operation of an ion exchanger, the effective exchange capacity of the ion exchanger is called the working exchange capacity.

The factors that affect the exchange capacity of work include: ① ion concentration in the inlet water; ② Control indicators for the exchange endpoint; ③ The height of the exchange agent layer; ④ The flow rate of water; ⑤ The pH value of water; ⑥ The particle size of the exchange agent; ⑦ The form of exchanging functional groups; ⑧ Whether the regeneration is sufficient, etc.

What are the different regeneration conditions between strong alkaline anion exchangers and strong acidic cation exchangers? Why?

Answer: The differences mainly manifest in the following aspects:

(l) Regenerant dosage. The regeneration specific consumption of cation exchangers is low, while the regeneration specific consumption of anion exchangers is high.

(2) Regenerative liquid concentration. The concentration of regeneration solution in cation exchangers is generally 3% to 5%, while the concentration of regeneration solution in anion exchangers is generally 1.5% to 4%.

(3) The temperature and regeneration time of the regeneration solution. There is no requirement for the temperature of the regeneration solution of the cation exchanger, and the regeneration time is relatively short, usually completed within 30-45 minutes; The regeneration liquid temperature of the anion exchanger is generally controlled at 40 ± 5oC, and the regeneration time takes 45-60 minutes to complete.

The main reason for the different regeneration conditions between the two is that the exchangeable groups in the strong alkaline anion exchange resin have little activity, and their double layer is easily compressed. Secondly, HSiO3- is difficult to replace, and its speed is also relatively slow.

How to prevent corrosion of water supply pumps?

Answer: Preventing corrosion of feedwater pumps should mainly focus on several aspects, such as deaeration of feedwater, adjusting the pH value of feedwater, and improving the material of feedwater pumps. The specific measures are as follows:

(l) Ensure the normal operation of the thermal deaerator, improve the deaeration efficiency, and combine with the addition of hydrazine treatment to completely eliminate residual dissolved oxygen in the feedwater.

(2) Reasonably select the material of the feedwater pump. The guide vanes and impellers of the feedwater pump are made of corrosion-resistant materials, such as chromium steel (2Cr13), stainless steel (lCr18Ni9Ti), etc.

(3) Stabilize the quality of the supplied water and carry out ammonification treatment to increase the pH value of the feed water within the range of 8.5 to 9.2.

(4) Prevent air leakage into the pump or prevent water vaporization to prevent cavitation.

How to prevent corrosion in the water supply system?

Answer: The main factors causing corrosion in water supply systems are oxygen and carbon dioxide in the water. Therefore, to prevent corrosion of the water supply system, efforts should be made to eliminate oxygen and carbon dioxide in the water. Currently, various power plants mainly take the following measures:

(1) Deoxygenation of water supply. Mainly using thermal deoxygenation, that is, using steam heating method to heat water to the boiling point at the corresponding pressure, so that the dissolved oxygen in the water can be resolved. At the same time, chemical deoxygenation is supplemented by adding hydrazine to the water to completely eliminate residual oxygen.

(2) Ammonia treatment of water supply. By utilizing the alkalinity generated by ammonia dissolved in water, the pH value of the water supply can be increased and adjusted, and controlled between 8.5 and 9.2 to form a stable protective film on the metal surface, thereby preventing corrosive media from corroding the metal in the water supply system. In addition, by utilizing the volatility of ammonia, the pH value of the condensate can be greater than 8, preventing carbon dioxide corrosion in the condensate system.

(3) Reduce the carbonate alkalinity of the makeup water. Generally, H-Na softening of water can be used, such as adding acid to the softened water and chemical desalination, to reduce the alkalinity of carbonate in the water to below 0.01mmol/L.

Why do we need to do anti-corrosion work on boilers that have been shut down for backup?

Answer: The metal surface of the standby boiler is prone to salt, scale, and slag accumulation. If it comes into contact with O2 and CO2 in the air, corrosion will occur. This type of corrosion is much more severe than corrosion during operation. When the economizer is running, it is generally prone to corrosion at the inlet. If anti-corrosion work is not carried out on the standby boiler, the entire pipeline will be corroded. Superheaters generally do not corrode during operation, but corrosion may occur during shutdown and standby, especially in the elbow section. The water-cooled wall tubes and steam drums of boilers are rarely subjected to oxygen corrosion during operation, but are highly susceptible to oxygen corrosion during shutdown and standby. Corrosion occurs during shutdown, which increases the amount of corrosion products in the water. At the same time, these corrosion products, such as Fe2O3 CuO, are corrosion promoters. This is an important cause of corrosion and scaling during operation.

Therefore, it is important to pay attention to anti-corrosion measures when shutting down standby boilers.

What are the basic principles for anti-corrosion of standby boilers?

Answer: There are many methods for preventing corrosion in standby boilers, but the basic principles are nothing more than:

The following points:

(l) Do not allow air to enter the water and steam system of the standby boiler. Maintain a certain steam pressure or feedwater pressure inside the boiler.

(2) Keep the metal surface of the standby boiler equipment fully dry. If using a hot and pressurized water discharge method, using furnace waste heat for drying or using hot air from adjacent operating boilers for drying, etc. Practice has proven that corrosion can be prevented when the relative humidity inside the standby boiler equipment is less than 20%.

(3) Form a protective film or adsorption film with anti-corrosion effect on the metal surface. If gas phase corrosion inhibitors (such as cyclohexylamine carbonate) are used for corrosion prevention after stopping the boiler and discharging water.

(4) Soak the metal surface in an aqueous solution containing deoxidizers or other protective agents. If immersed in a solution of hydrazine or ammonia.

(5) Fill the standby boiler equipment with inert gas. If high-purity nitrogen or ammonia is injected.

In fact, the above principles can be summarized as starting from removing the cathodic depolarizer to polarize the cathode, forming a stable protective or adsorption film to polarize the anode, or preventing electrochemical corrosion from occurring on the metal surface without electrolyte solution.

How to choose the protection method for shutting down standby boilers?

Answer: When choosing the protection method for shutdown standby boilers, the following main issues should be considered based on specific conditions: ① the structural form of the boiler body; ② The length of standby time; ③ The temperature of the surrounding environment; ④ On site equipment conditions; ⑤ The source and quality of water, etc.

What are the reasons for the formation of iron oxide scale? What are its characteristics?

Answer: Iron oxide scale is a common type of scale in the water-cooled wall tubes of boilers in thermal power plants. The main reason for its formation is that the local heat load on the heating surface of the boiler is too high; The iron content in boiler water is relatively high; Poor boiler water circulation; There are many corrosion products on the metal surface.

Iron oxide scale is generally in the form of shells, some of which are scaly protrusions. The surface of the scale layer is brown, while the interior and bottom are black or gray. After the scale layer peels off, there is a small amount of white substance on the metal surface, which is mainly a compound of silicon, calcium, magnesium, and phosphate. Some scales also contain a small amount of sodium hydroxide. The major characteristic of iron oxide scale is that the metal surface under the scale layer is subjected to varying degrees of corrosion damage, from pitting, ulceration to perforation.

How to prevent the generation of iron oxide scale in boilers?

Answer: To prevent the generation of iron oxide scale in boilers, the following aspects should be taken into consideration:

(l) Newly installed boilers must undergo chemical cleaning. Remove impurities such as mill scale, welding slag, and corrosion products from the boiler equipment.

(2) Try to reduce the oxygen and iron content of the feedwater as much as possible.

(3) Improve the dosing treatment inside the boiler and strengthen boiler discharge.

(4) Strictly supervise the water quality in the boiler water circulation system during unit startup, such as strengthening drainage and water exchange work.

(5) Take anti-corrosion measures during equipment shutdown or maintenance.

In addition, in terms of boiler structure and operation, it is necessary to avoid excessive local heat load on the hot surface metal to maintain normal combustion and good water circulation conditions of the boiler during operation.

How is copper scale formed on the heating surface of the boiler? How to prevent it?

Answer: Copper scale on the heating surface of the boiler is mainly caused by the electrochemical process of reducing copper oxide into metallic copper that enters the boiler with the feed water. This process is not related to the pressure of the boiler. It is mainly in the area where the heat load on the heating surface is too high, where the oxide film on the metal surface is damaged and a local potential difference is formed, causing the boiler metal to transfer into the boiler water and become divalent iron ions. The released electrons are absorbed by the copper ions, forming a metal copper precipitate on the pipe wall.

The precipitation amount of copper increases with the increase of boiler heat load, and its electrochemical process is as follows:

Fe Fe2+++2e

Cu2++2e Cu

Preventing the formation of copper scale should be approached from two aspects: first, try to prevent corrosion of copper components in thermal equipment and reduce the copper content in the feedwater; Secondly, in terms of boiler operation, try to avoid the occurrence of excessive local heat load as much as possible.

What is boiler water; Salt temporarily disappears; Phenomena? What are the hazards of it?

Answer: When the load of the drum boiler increases, some soluble sodium salts in the boiler water precipitate from the boiler water and deposit on the wall of the furnace tube, causing their concentration in the boiler water to significantly decrease. However, when the boiler load decreases or the boiler is shut down, the sodium salts deposited on the wall are dissolved again, causing their concentration in the boiler water to increase again. This phenomenon is called "; Salt temporarily disappears; Phenomena, also known as"a; Salt hiding; Phenomena.

&Quota; Salt hiding; The harmfulness of the phenomenon is similar to that of scale, with the following points:

(l) It can react with other deposits on the furnace tube, such as metal corrosion products and silicon compounds, to form insoluble scale.

(2) Poor heat transfer performance can cause overheating, deformation, and even explosion of the furnace tube metal.

(3) Can cause metal corrosion under sediment.

How to prevent boiler water generation; Salt temporarily disappears; Phenomena?

Answer: Prevent boiler water generation; Salt temporarily disappears; Phenomena, the following measures should generally be taken:

(l) Improve the combustion conditions of the boiler to ensure even heat load on each section of the furnace tubes; Prevent coking and slagging in the furnace, and avoid excessive local heat load on the furnace tubes.

(2) Improve the flow conditions of boiler water inside the boiler tubes to ensure the normal operation of water circulation. For example, cancel the horizontal evaporation tube and increase the inclination of the furnace tube to above 15 ℃ to 30 ℃.

(3) Improve the dosing treatment inside the boiler and limit the phosphate content in the boiler water. If using low phosphate treatment or pure phosphate treatment, etc.

(4) Reduce sediment in boiler tubes and improve their cleanliness.

What is a corrosion inhibitor? What are its characteristics?

Answer: During the boiler pickling process, adding a small amount of chemical to the pickling solution can inhibit or slow down the corrosion of metal by the pickling solution. This type of drug is called a corrosion inhibitor.

The characteristics of corrosion inhibitors are as follows:

(l) Adding a very small amount (dry parts or tens of thousands of parts) can greatly reduce the corrosion rate of acid solution on metals;

(2) Will not reduce the ability of acid washing solution to remove sediment;

(3) Will not decrease its ability to inhibit corrosion with the passage of cleaning time;

(4) Has no effect on the mechanical properties and metallographic structure of the metal;

(5) Non toxic, safe and convenient to use;

(6) The waste liquid discharged after cleaning will not cause environmental pollution and public hazards.

Why can corrosion inhibitors play a role in slowing down corrosion? How to choose corrosion inhibitors during pickling?

Answer: There are two reasons why corrosion inhibitors can slow down corrosion:

(l) The corrosion inhibitor molecules adsorb on the metal surface, forming a thin protective film, thereby inhibiting corrosion.

(2) Corrosion inhibitors react with other ions on the metal surface or solution, and their reaction products cover the metal surface, thereby inhibiting corrosion.

The determination of the type and amount of corrosion inhibitor added during pickling is related to the type and concentration of the cleaning agent, as well as the cleaning temperature and flow rate, as each corrosion inhibitor has its suitable temperature and flow rate range. The effect of corrosion inhibitors on reducing corrosion rate generally decreases with the increase of cleaning solution temperature and flow rate. Due to various factors, the selection of corrosion inhibitors should be determined through small-scale experiments.

Why does the acid washing of a boiler generate" Copper plating; Phenomena? What are the hazards? How to eliminate it?

Answer: When running a boiler pickling, if the copper content in the sediment inside the boiler is high, the pickling solution will react with the sediment with a higher copper content according to the following equation:

Fe-2e Fe2+

Cu2++2e Cu

The reaction result is that the steel is corroded, and Cu precipitates on the surface of the steel, causing the steel surface to be unevenly coated with metallic copper.

Due to the different electrode potentials of copper and iron, a corrosive battery is formed when copper and iron come into contact, which can cause severe pitting corrosion of the cleaned metal.

Eliminating the pickling process; Copper plating; Phenomena, the following measures can be taken:

(1) When the CuO content in the sediment inside the boiler is less than 5%, masking agents can be added to the cleaning solution to remove copper;

(2) When the content of CuO in the sediment inside the boiler is 5% dry, during the acid washing process, it is necessary to consider adding an ammonia washing step. Copper ions generate stable copper ammonia complex ions in the ammonia water to prevent; Copper plating; The occurrence of phenomena.

Why is it necessary to rinse the boiler with a dilute citric acid solution after the acid cleaning is completed?

Answer: The purpose of rinsing with citric acid is to utilize the chelating properties of citric acid with iron ions to remove residual iron ions in the pickling system and the potential secondary rust that may occur during rinsing after pickling, providing more favorable conditions for passivation treatment. In addition, it can also shorten the rinsing time after pickling and reduce water consumption.

What is corrosion under sediment inside a boiler? How to prevent it?

Answer: When there is scale, water residue, or metal corrosion products attached to the metal surface inside the pot, severe corrosion will occur below it, which is called corrosion under the sediment inside the boiler. This type of corrosion is related to local concentration of boiler water, and is therefore also known as medium concentration corrosion.

To prevent this type of corrosion, the following measures are generally taken:

(1) Necessary chemical cleaning should be carried out on newly installed or operated boilers.

(2) Do a good job in anti-corrosion work of the water supply system and reduce the copper and iron content in the water supply.

(3) Do a good job in anti-corrosion work for standby boilers to prevent corrosion inside the boiler during the standby period.

(4) Improve the quality of water supply to minimize the introduction of corrosive components into the boiler.

(5) Choose a reasonable water treatment method inside the boiler, regulate the water quality of the boiler, and eliminate or reduce corrosive impurities in the boiler water.

What is coordinated pH phosphate treatment?

Answer: Coordinated pH phosphate treatment is a strict and reasonable method for regulating water quality in pots. It can not only prevent the generation of calcium and magnesium scale, but also prevent corrosion of boiler tubes. This treatment essentially involves adding different proportions of phosphates, namely trisodium phosphate and disodium hydrogen phosphate (or disodium hydrogen phosphate), to the pot according to the hardness and alkalinity of the feed water. The addition of disodium hydrogen phosphate or disodium hydrogen phosphate is mainly to neutralize the free sodium hydroxide brought into the boiler water from the feedwater, and the reaction is as follows:

Na2HPO4+NaOH Na3PO4+H2O

And trisodium phosphate can establish hydrolysis equilibrium in water according to the following formula:

Na3PO4+H2O Na2HPO4+NaOH

So, in addition to maintaining a certain amount of excess phosphate ions in the boiler water, the added trisodium phosphate can also maintain the pH value of the boiler water due to its hydrolysis ability to produce a certain amount of sodium hydroxide. When the boiler water undergoes local evaporation and concentration, the hydrolysis equilibrium is carried out in the direction of generating trisodium phosphate, which will not cause the concentration of sodium hydroxide to be harmful to the metal. Even under high heat loads, it can prevent the metal from being corroded by concentrated alkali.

What is the boiler discharge rate? How to calculate the boiler discharge rate?

Answer: The percentage of boiler discharge per unit time to boiler evaporation is called the boiler discharge rate.

What is the impact of salt content in boiler water on steam quality?

Answer: When the salt content of boiler water exceeds a certain value, it has little effect on steam quality. However, when the salt content of boiler water exceeds a certain value, the impact on steam quality significantly increases.

(1) As the salt content of boiler water increases, its viscosity increases, making it difficult for water bubbles in the water layer to merge into large bubbles. Therefore, small bubbles are filled in the water chamber of the steam drum, and the small bubbles rise slowly in the water, resulting in increased water level expansion and reduced height of the steam space, which is not conducive to steam water separation.

(2) When the impurity content in the boiler water increases to a certain extent, a foam layer will be formed at the steam water interface. The foam layer will reduce the height of the steam space, affecting the separation of steam and water. When the foam layer is too high, the steam can directly take away the foam, causing a large amount of steam with water.

When the salt content of boiler water increases to a certain extent, both factors will deteriorate the steam water separation effect, causing a large amount of steam to carry water, resulting in a sharp increase in steam salt content.

What is the impact of boiler operating conditions on steam quality?

Answer: The operating conditions of a boiler, such as its load, the speed of load changes, and the water level of the steam drum, have a significant impact on steam quality.

(l) Drum water level. If the water level in the steam drum is too high, the height of the steam space in the upper part of the steam drum will inevitably decrease, which will shorten the distance of water droplets splashing to the steam outlet, which is not conducive to natural separation and increases the amount of water carried by the steam.

(2) Boiler load. When the boiler load increases, due to the increase in kinetic energy of the steam water mixture, the amount and kinetic energy of water droplets formed by mechanical impact splashing also increase. In addition, the flow rate of steam leading out of the steam drum increases, and the flow rate accelerates. Therefore, the ability of steam to carry water increases, and the amount of water carried by the steam also increases.

(3) Changes in boiler load, water level, pressure, etc. Excessive fluctuations in boiler load, water level, and pressure can also cause a large amount of steam to carry water. For example, when the boiler load suddenly increases and the pressure suddenly drops, due to the decrease in the boiling point of water, the boiler water will undergo rapid boiling, producing a large number of steam bubbles. This will cause the bubble to burst and produce a large number of small water droplets, and the water level expansion will also be greatly intensified. Reduce the vapor space. All of these will cause an increase in the amount of water carried by the steam, leading to an increase in the salt content of the steam.

What is the pattern of impurities carried by saturated steam dissolution?

Answer: The following rules apply to impurities carried by saturated steam dissolution:

(l) The ability of saturated steam to dissolve impurities is related to the boiler pressure. The greater the pressure, the stronger the ability to dissolve and carry.

(2) Saturated steam dissolution carries impurities selectively. The solubility of saturated steam varies for various substances, such as common substances in boiler water. According to their solubility in saturated steam, they can be divided into three categories: the first category is silicic acid (H2SiO2, H2Si2O3, H4SiO4, etc.), which has a higher solubility; The second type is NaCl, NaOH, etc., which have much lower solubility than silicic acid; The third type is Na2SO4, Na3PO4, and Na2SiO3, which are difficult to dissolve in saturated steam.

(3) The dissolution carrying capacity increases with the increase of pressure. Because as the saturated vapor pressure increases, the vapor density also increases, and the solubility of various substances in it also increases.

(4) Saturated steam has a characteristic of dissolving and carrying silicon compounds. The state of silicon compounds in boiler water can be divided into dissolved silicates and solution silicic acid. The saturated steam mainly carries solution silicic acid, which has little ability to dissolve silicates.

How is the distribution of salt deposits inside the superheater?

Answer: The deposition of various impurities carried by saturated steam in the superheater is as follows:

(l) Na2SO4 and Na3PO4. The higher the temperature, the smaller the solubility of these impurities, so they deposit in the superheater (or are carried by steam to the turbine as solid particles).

(2) NaOH. The higher the temperature, the greater the solubility, so it is carried as thick droplets to the turbine. But NaOH thick droplets also adhere to the wall of the superheater tube, react with CO2 to generate Na2CO3 and deposit in the superheater.

(3) NaCl. When the pressure is greater than 9.8MPa, its solubility is high and it often dissolves in superheated steam and is carried to the turbine.

(4) H2SiO3 or H4SiO4. Both lose water and become SiO2, which has a high solubility in superheated steam and is generally carried to the steam turbine.

Therefore, the deposition of salt substances in the superheater can be summarized as follows:

(l) The sediment in the superheater of medium and low pressure boilers is mainly composed of sodium compounds (Na2SO4, Na3PO4, Na2CO3, NaCl, etc.).

(2) The deposits in the superheater of high-pressure boilers are mainly Na2SO4 and Na3PO4, with very little content of other sodium salts.

(3) The amount of salt deposits in the superheater of ultra-high pressure boilers is very small.

What is the reason for the formation of deposits inside the steam turbine? What are its characteristics?

Answer: The reasons for the formation of deposits inside the steam turbine are as follows:

(l) During the work process of superheated steam in the turbine, its pressure and temperature gradually decrease, and the solubility of sodium compounds and silicic acid in the steam also decreases, so they deposit in the turbine.

(2) Small NaOH droplets and some solid particles in the steam adhere to the steam flow section of the turbine, forming sediment.

The deposition characteristics of various impurities in the steam turbine are as follows:

(l) Sodium compounds deposit in the high-pressure section of the steam turbine.

(2) Silica is dehydrated to form quartz crystals, which deposit in the middle and low pressure sections of the steam turbine.

(3) Iron oxides can deposit on all stages of turbine blades.

What is the distribution of salt deposits inside the steam turbine?

Answer: The distribution of salt deposits inside the steam turbine is as follows: ① The amount of deposits varies in different stages; ② The chemical composition of sediments varies among different grades; ③ Uneven distribution on partitions and impellers at all levels; ④ There is very little sediment in heating units and units that are frequently started and stopped.

Industrial water equipment, chemical water equipment, electronic water equipment

What specific measures should be taken to obtain clean steam?

Answer: To obtain clean steam, the following measures must be taken:

(l) Try to minimize impurities entering the boiler water. Specific measures include: ① improving the quality of supply water; ② Reduce the supply water rate; ③ Prevent corrosion of the water supply system; ④ Timely chemical cleaning of the boiler.

(2) Strengthen boiler discharge. Carry out continuous and regular pollution discharge work.

(3) Improve the internal device of the steam drum. Including improving the steam water separation device and steam cleaning device.

(4) Adjust the operating conditions of the boiler. This includes adjusting the boiler load, drum water level, saturated steam pressure and temperature, avoiding excessive changes in operating parameters, and reducing the salt content of boiler water.

What is the thermochemical test of a drum boiler? What is the purpose of thermochemical experiments?

Answer: Thermochemical testing is a boiler operation method that determines reasonable boiler water quality standards and ensures good steam quality by adjusting the salt content of boiler water and changing boiler operating parameters. In other words, it is a specialized test conducted on the characteristics and water quality of the boiler.

The purpose of thermochemical experiments is to obtain the relationship between water quality, steam quality, boiler thermal process, boiler operating conditions, and equipment characteristics through experiments; Under the condition of good steam quality, determine the boiler water quality standards and the optimal operating conditions for the boiler.

Under what circumstances do boilers need to undergo thermochemical tests?

Answer: A thermochemical test must be conducted in the following situations: ① After a newly installed boiler is put into operation for a period of time; ② Modified boiler; ③ When the operation mode of the boiler changes, such as significant changes in the composition or quality of the feedwater; Changes in combustion conditions; Increase the rated evaporation capacity; Change the water treatment method inside the boiler, etc. ④ Due to poor steam quality, salt accumulation occurs in the superheater and turbine.

What is stress corrosion? What are the characteristics of stress corrosion?

Answer: The corrosion of metal materials under stress and corrosive media is called stress corrosion.

The characteristic of stress corrosion is that the fracture surface is brittle fracture, which is different from mechanical fracture. There are many cracks around the fracture surface, most of which develop from the contact surface of the medium to the metal substrate. Cracks can develop along the grain edge or transgranular due to different materials and media. In general, ordinary steel undergoes intergranular corrosion; Austenitic steel is subjected to transgranular corrosion.

How to determine if there is adhesion on the inner wall of the condenser copper tube?

Answer: After the formation of adhesion on the inner wall of the condenser copper tube, there are generally the following characteristics:

(l) The water flow resistance within the system increases. At the same water flow rate, the water flow resistance of a condenser with attachments is significantly higher than that of a condenser with clean copper pipes.

(2) The cooling water flow rate decreases. Due to the increased resistance of the cooling water system, the flow rate of the cooling water decreases when the cooling water pressure remains constant.

(3) The temperature at the outlet increases. Due to the poor thermal conductivity of the attached material, the outlet temperature of the cooling water and the exhaust temperature of the turbine increase.

(4) The vacuum degree of the condenser has decreased. All of the above reasons can cause an increase in the temperature of the condensate water inside the condenser, resulting in a decrease in the vacuum degree of the condenser.

In the production practice of thermal power plants, under the same electrical and thermal loads of the steam turbine generator set, the decrease in vacuum degree of the condenser is often used to determine the amount of generated attachments inside it and whether it needs to be shut down for cleaning.

How to determine if there is scaling phenomenon inside the copper tube of the condenser?

Answer: Whether there is scaling inside the copper tube can be determined based on the results of water quality analysis.

(l) Determine based on the salt concentration rate of the cooling water.

What are the forms of corrosion in condenser copper pipes?

Answer: The corrosion of copper pipes in condensers varies in various forms due to factors such as the structure, material, usage conditions, and cooling water quality of the condenser. There are generally several common types: ① ulcer corrosion; ② Impact corrosion; ③ Dezinc corrosion; ④ Hot spot corrosion; ⑤ Stress corrosion; ⑥ Corrosion fatigue; ⑦ Ammonia corrosion on the steam side; ⑧ Corrosion caused by cooling with contaminated seawater.

Under what circumstances are copper pipes in condensers prone to dezincification corrosion? How to prevent it?

Answer: Copper pipes in condensers are prone to dezincification corrosion under the following conditions:

(l) The composition of copper alloy contains impurities. If copper and zinc alloys contain iron, it will counteract the inhibitory effect of arsenic on zinc removal and accelerate the zinc removal corrosion of brass pipes. In addition, the inclusion of slag in the brass tube alloy can cause severe dezincification corrosion in that area.

(2) The cooling water is contaminated. After the cooling water is polluted, the corrosive substances in the water increase, which reduces the anti zinc ability of arsenic in the brass tube. Even if the brass tube contains arsenic above 0.03%, zinc removal corrosion will occur.

(3) The flow rate of cooling water is too slow.

(4) The temperature of the condenser tube wall is too high.

(5) There are permeable attachments on the inner surface of copper pipes.

To prevent dezincification corrosion of condenser copper pipes, the following measures can be taken:

(l) Select different arsenic containing copper pipes according to the quality of cooling water.

(2) Reduce the wall temperature of the condenser.

(3) Increase the flow rate of water inside the pipe to avoid long-term stagnation of cooling water inside the pipe.

(4) The surface of the copper tube is coated with ferrous sulfate.

What is the stress corrosion of copper tubes? What are the factors that cause it? How to prevent it?

Answer: Under the action of stress (especially tensile stress), combined with corrosive media, corrosion cracks occur along the grain boundaries over time, causing damage to the pipes. This phenomenon is called stress corrosion.

The stress corrosion of copper pipes is not only related to the effect of stress, but also to many other factors. Under the action of seat force, substances such as oxygen, ammonia, and hydrogen sulfide in water are important factors that promote stress corrosion.

To prevent stress corrosion of copper pipes, the following measures are generally taken:

(l) During the manufacturing, transportation, and assembly process of copper pipes, attention should be paid to avoiding stress. When there is stress, anneal it before use.

(2) Prevent copper pipes from vibrating during operation.

(3) Choose appropriate copper pipes and materials.

(4) The arsenic content of aluminum brass should not be too high.

How to check the leakage of condenser copper pipes during operation?

Answer: There are several commonly used methods for checking the leakage of condenser copper pipes during operation:

(l) Thin film method. The specific method is to press a thin film with a thickness of 0.02-0.03mm on each end of the condenser tube plate during the half face inspection of the turbine during load reduction. As a vacuum is formed inside the leaking tube, the leaking tube can be detected based on the suction of the tube opening film.

(2) U-shaped pipe water level method. During the half face inspection of the turbine during load reduction, open the large covers at both ends of the condenser, block one end of the pipe opening, and insert a U-shaped glass tube with a rubber plug and colored liquid into the other end of the pipe opening. When the tube leaks, a liquid level difference occurs inside the U-shaped tube. In order to shorten the leak detection time, a water level gauge can be installed in the water chamber of the condenser. The method of slowly discharging cooling water is used to observe the changes in the conductivity of the condensate. After initially determining the leak location, a U-shaped tube is used to determine the specific leak location.

(3) Candle method (or smoking method). During the half face inspection of the turbine during load reduction, open the large covers at both ends of the condenser, block one end of the pipe opening, and use a lit candle or cigarette to slowly move along the pipe opening at the other end. The leaking pipe can be detected by suction of fire or smoke into it due to vacuum. You can also use this method to determine the specific location of the leak after draining the water from the water chamber in combination with question (2).

(4) Fluorescence method. During the half face inspection of the turbine during load reduction, drain the water in the water chamber, open the large covers at both ends of the condenser, and inject water with fluorescent agent into the steam side of the condenser. To allow the fluorescent liquid to quickly seep out of the leak, a certain pressure can be applied on the vapor side, and after half an hour, it can be illuminated with a light source. When illuminated, move horizontally back and forth from top to bottom, and the fluorescent liquid will emit a bright yellow green light at the leak.

(5) Instrumental method. For example, using an ultrasonic leak detector for leak detection.

How to deal with any leakage found in the condenser during the operation of the steam turbine?

Answer: If a leakage is found in the condenser, the following measures can be taken based on the degree of deterioration of the condensate water quality:

(1) The hardness of the condensate water in the high-pressure unit is greater than 2 μ Mo1/L, medium pressure unit condensate hardness greater than 3 μ When Mo1/L, due to slight leakage, the cooling water inlet can be treated with sawdust. If the water quality deteriorates due to the loose expansion of the copper pipe, it is recommended that the turbine operator increase the exhaust chamber temperature or reduce the cooling water pressure to reduce the amount of water leakage.

(2) If the leakage time is long and the condensate water quality still does not improve after the above treatment, the sawdust treatment can be stopped, the turbine can be reduced in load, and a half surface inspection of the condenser can be carried out. Identify the leakage point, plug it, and then put it into operation.

(3) If the quality of condensate water deteriorates severely and affects the quality of feedwater, effective measures can be taken based on the specific situation of each power plant. Such as strengthening the supervision of boiler water and steam quality, adjusting the dosage of water treatment in the boiler, and increasing the boiler discharge volume. If necessary, stop the machine to make up for leaks.

How to prevent corrosion on the cooling water side of condenser copper pipes?

Answer: To prevent corrosion of condenser copper pipes, water purification methods cannot be used because the flow rate of cooling water is too high. Generally, suitable pipe materials are selected for surface coating of copper pipes, and certain chemicals are added to water for treatment. The specific measures are as follows:

(l) Reasonably select copper pipe materials for condensers based on the quality of cooling water.

(2) Maintain, handle, and install copper pipes before they are put into operation.

(3) The surface of the copper tube is treated with ferrous sulfate to form a film.

(4) The copper pipes of the condenser in operation are protected by cathodic protection.

(5) Install protective sleeves or apply epoxy resin adhesive to the ends of copper pipes.

(6) Stabilize the water quality of the cooling water.

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