Water treatment attendant question bank (senior worker)

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Short answer: What is the relationship between the existence form of carbonic acid compounds in water and the pH value of water? Answer: Carbonic compounds exist in several different forms in water: Gas dissolved in water (so-called free CO2) ； Molecular carbonic acid H2CO3 ； Bicarbonate HCO3- and carbonate CO32-. There is the following balance relationship between these four: CO2+H2O H2CO3 H2CO3 H++HCO3- HCO3- H++CO32- If these balanced equations are connected, it can be written as the following formula: CO2 + H2O H2CO3 H+ + + HCO3- 2H + + CO32- In the above series of balances, the balance between CO2 and H2CO3 is actually strongly inclined to generate CO2. The amount of H2CO3 in the water is very small (usually less than 1%), so the process of generating H2CO3 can be omitted, and the equilibrium formula can be changed to the following formula: Among them: (at 25℃, K1=4.45×10-7) (at 25℃, K1=4.69×10-11) According to the above situation, it can be seen that it plays a decisive role in the movement of equilibrium. The relationship between the relative values ​​and concentrations of CO2, HCO32- and CO32- in water is shown in Figure 4-3. It can be seen from Figure 4-3 that: (1) When pH<4, there is only free CO2 in the water. (2) When the pH value increases, the balance moves, decreases, and increases. When pH=8.3~8.4, more than 98% of the carbonic acid compounds exist in the form of HCO3-. (3) When the pH value increases again (when it is greater than 8.3), CO2 disappears, decreases, and increases. When pH=12, carbonic acid compounds in the water almost completely exist in the form of CO32-. What is the relationship between the existence of silicic acid compounds in water and the pH value of water? Answer: Acid compounds are one of the main impurities in natural water. They have many forms in water and are relatively complex compounds. The different forms of silicic acid compounds in water are closely related to the pH value of water. When the pH is <7, there are actually only silicic acid molecules in the water and no silicate ions. Therefore, when the pH value is low (in acidic solution), the amount of colloidal silicic acid in the water increases significantly. ； When the pH value is >7, both H2SiO3 and HSiO3- exist in the water. ； When pH=11, the water is mainly HSiO3- ； SiO32- ions only appear in highly alkaline water (pH>11). What are the pH requirements of water for coagulation treatment? Answer: The pH value of water has a great influence on the coagulation process. Different coagulants have different requirements for the pH value of water. Therefore, during coagulation treatment, the pH value of the water after adding the coagulant must be strictly controlled. The requirements for pH value of different coagulants are as follows:: (1) Aluminum salt. Aluminum salts form aluminum hydroxide colloids after ionization and hydrolysis in water. The pH value has two effects on the colloids. First, aluminum hydroxide is an amphoteric hydroxide. When the pH value of water is lower than 5.5, aluminum hydroxide becomes alkaline and is dissolved. The reaction is as follows: The reaction result of A1(OH)3+3H+ → A13++3H2O increases the residual aluminum content in the water. When the pH value of water is higher than 7.5, aluminum hydroxide becomes acidic, and metaaluminate (AlO2-) appears in the water. The reaction is as follows: AI(OH)3+OH--→ AlO2-+2H2O The result of the reaction is that the amount of residual aluminum in the water also increases. Therefore, it cannot produce AI(OH)2 flocculation. Second, when the pH value of water is between 5.5 and 8.8, the aluminum hydroxide colloidal particles are positively charged. When the pH of water is <5, the colloidal particles are negatively charged ； When the pH of water is >8, aluminum hydroxide dissolves. Therefore, when the pH value of water is higher than 8.0 or lower than 5.0, it affects the formation of positively charged aluminum hydroxide colloid. Therefore, when using aluminum salt as coagulant, the pH value of water should be 6.5 to 7.5. (2) Iron salt. Iron salts are ionized and hydrolyzed in water to form positively charged iron hydroxide colloids. The reaction is as follows: 4FeSC4+10H2O+O2→ 4Fe(OH)3+4H2SO4 During this reaction, Fe2+ is easily oxidized to Fe3+ to form Fe(OH)3 colloid when the pH is >8.5 ； When the pH value is low, the above reaction is completed slowly. Therefore, when iron salt is used as a coagulant 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 coagulants used, the most realistic pH value should be determined through small experiments. What are the advantages of using polymerized aluminum as coagulant? Answer: Polyaluminum coagulant has the following advantages: (1)Wide range of application. It has excellent coagulation effect on low turbidity water, high turbidity water, colored water and some industrial wastewater. (2) The dosage is small (calculated as Al2O3). For low turbidity water, its dosage is equivalent to l/2 of aluminum sulfate. ； For high turbidity water, its dosage can be reduced to 1/3 to 1/4 of the aluminum sulfate dosage. (3) Simple operation. After adding medicine, the alkalinity of the water decreases less, so the pH value of the water decreases less. The optimal pH value of coagulation has a wide range. Generally, good results can be achieved with pH values ​​from 7 to 8, and the effect is still stable at low temperatures. (4) The formation of flocculation is fast. Because this agent forms flocculation quickly, it can reduce the size of the clarification equipment. (5) There is no harm in adding too much medicine and it will not worsen the water quality. What is the uneven coefficient of filter material? What impact does its size have on filter operation? Answer: The uneven coefficient of filter material is often expressed in KB. It refers to the ratio of the sieve hole diameter d80 through which 80% (by mass) of the filter material can pass and the sieve hole diameter d10 through which 10% of the filter material can pass. That is, the size of the filter material particles is uneven, which has two adverse consequences.: First, the backwash operation is difficult because if the backwash intensity is too strong, tiny filter particles in the upper part will be brought out. ； The backwash intensity is too small and cannot loosen the lower filter layer. Second, the filtration condition deteriorates because fine filter material particles are concentrated on the surface of the filter layer, causing suspended solids in the water to be trapped 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 feeding acid and alkali during countercurrent regeneration ion exchanger regeneration? How to deal with it? Answer: The reason why it is difficult to feed acid and alkali during countercurrent regeneration ion exchanger regeneration may be:: (l) The back pressure in the ion exchanger is too high. (2) The acid and alkali discharge devices are clogged. (3) When the ion exchanger is regenerated, the main valve fails and the regeneration liquid flows 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 low. The processing method is as follows: (l) The ion exchanger maintains a certain back pressure (>0.05MPa). (2) When the acid discharge and alkali discharge devices and the acid and alkali addition injectors are damaged, they should be repaired and replaced in time. (3) During the regeneration process, carefully check the opening and closing conditions of the valves of each ion exchanger to prevent failure and loose closing. (4) Regularly clean the nylon mesh sleeves of the acid and alkali discharge devices. What are the main reasons for the reduction of the working exchange capacity of the ion exchanger during operation? Answer: The working exchange capacity of the ion exchanger is reduced during operation. The possible reasons are as follows:: (1) When new resin starts to be 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 become stable. (2) The surface of the exchanger particles is contaminated by suspended solids and even adheres. (3) The raw water contains Fe2+, Fe3+, Mn2+ plasma, which poisons the exchange agent and makes the color darker. (4) The dose of regenerant is small and the regeneration is not sufficient. (5) The operating flow rate is too large. (6) The salt content and hardness of the raw water in the dry season are too high. (7) The resin layer is too low or the resin gradually decreases. (8) The regenerant is of poor quality and contains too many impurities. (9) The water distribution device, drainage device, and regeneration liquid distribution device are blocked or damaged, causing deviation. (10) When the ion exchanger is backwashed, the backwash intensity is not enough, and more suspended solids accumulate in the resin layer, which bond with the resin to form mud balls or mud cakes, causing the water to flow biasedly. The countercurrent regeneration ion exchanger failed just after it was put into operation. What is the reason? How to deal with it? Answer: This behavior may occur because: (1) There are problems with the regeneration operation, such as insufficient top pressure causing resin chaos. (2) The flow rate of the regeneration liquid is too large, causing resin chaos. (3) The pressure grease layer becomes thinner, causing the regeneration fluid and top pressure fluid to flow biasedly. The processing method is as follows: (1) Strengthen regeneration operation training and master regeneration operation technology correctly and skillfully. (2) Adjust the regeneration fluid flow rate. (3) Replenish the resin (or white ball) of the grease layer. (4) Carry out large backwash. The quality of the outlet water from the countercurrent regeneration ion exchanger has deteriorated or the operating cycle has been significantly shortened. What is the reason? How to deal with it? Answer: This behavior may occur because: (l) During the regeneration operation, the water is replaced or backwashed, and desalted water (or softened water) is not used, causing the lower resin layer to be in a failed state, and Na+ (or hardness or HsiO3-) leaks continuously at the beginning of operation. (2) The pressure of the top pressure fluid is too high, which affects the amount of regeneration fluid entering. The processing method is as follows: (1) Be sure to use demineralized water (or softened water) for replacement or backwashing. (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 deal with it? Answer: The reason for this phenomenon in the floating bed may be that: (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 fluid inlet device are shared, the nylon mesh wrapped on the surface is partially blocked by broken resin, causing uneven distribution of the regeneration fluid. The processing method is as follows: (l) Modify the regeneration waste liquid drain pipe into an inverted U-shaped pipe. (2) Remove the resin from the body, perform external backwashing, and check and repair the water outlet device. The water outlet resistance of the floating bed ion exchanger increases, or even no water comes out. What is the reason? How to deal with it? Answer: The reason for this phenomenon in the floating bed may be that: (1) There is an increase in broken resin and suspended solids in the resin layer. (2) The nylon mesh of the water outlet device is damaged, and a large amount of resin accumulates in the resin trap, blocking the water outlet. The processing 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. The floating bed ion exchanger failed just after regeneration and was put into operation. What are the reasons? How to deal with it? Answer: The reason for this phenomenon in the floating bed may be that: (1) When getting up, the inlet water pressure is small, and the resin fails to form a bed and chaos occurs. (2) The resin in the exchanger cannot be packed naturally, the water cushion is too high, and the resin layer is disordered. The processing method is as follows: (l) When starting, increase the flow rate when getting up. (2) Fill the resin and lower the height of the water cushion. What are the pros and cons of using hydrochloric acid and sulfuric acid as regenerants for H-type ion exchangers? Answer: The selection of regenerant is a very important link in the water treatment process. It directly affects the exchange capacity of the exchange resin and the quality of the effluent. As the regenerant of H-type ion exchanger, hydrochloric acid has the advantages of easy operation, good water quality, high exchange capacity of the exchange resin, and no precipitation during regeneration. This is because hydrochloric acid is a monobasic acid and is easy to ionize, and a higher concentration of regeneration solution can be used to achieve good regeneration effects. Therefore, the exchange capacity of resin regenerated with hydrochloric acid can be nearly doubled compared with that of regenerated with sulfuric acid, thereby extending the operating cycle of the exchanger, reducing the number of regenerations, and saving self-consumption water. However, the price of hydrochloric acid is higher, and the cost of water production is higher than that of regeneration with sulfuric acid. The acid storage equipment and its system need to be anti-corrosion, which requires more resources. Measures need to be taken to prevent acid mist from polluting the environment. The cost of water production using sulfuric acid to regenerate the H-type exchanger is lower. Concentrated sulfuric acid does not corrode steel, so ordinary steel containers can be used for storage, saving investment. However, sulfuric acid is a dibasic acid with low activity and incomplete ionization, so the effect of regenerating resin is poor. The exchange capacity of regenerated resin is only half of that of hydrochloric acid regeneration, with large water consumption and poor water quality. In addition, when regenerating resin with sulfuric acid, calcium sulfate precipitation is likely to occur, so the regeneration operation is troublesome (step-by-step regeneration is required). To ensure equipment and personal safety, safety measures are in place to prevent water from flowing back into the concentrated sulfuric acid equipment. The nozzle and mixing tube of the acid injector must be made of high-temperature-resistant and corrosion-resistant materials, such as polytetrafluoroethylene and aluminum antimony alloy. At present, most power plants use H-type ion exchangers for hydrochloric acid regeneration. Based on technical and economic comparisons, it is more advantageous to use hydrochloric acid than sulfuric acid. In the chemical desalination system of water, why are the anion exchangers placed after the cation exchangers? Answer: In chemical desalination systems, the anion exchanger is placed after the cation exchanger for the following reasons: (l) After the raw water is exchanged by the cation exchanger, the effluent becomes acidic, which is conducive to the exchange reaction of the anion exchanger and has high silicon removal efficiency. (2) Raw water directly enters the anion exchanger for exchange, which can produce insoluble compounds, block the cross-linked holes inside the exchange resin, and reduce the exchange capacity of the anion exchange resin. (3) There is a large amount of carbonate in the raw water, which can be decomposed into H2O and CO2 after passing through the cation pre-exchanger. After CO2 is removed by the carbon remover, the total amount of anions entering the anion exchanger is reduced, thereby extending the operating cycle of the anion exchanger and reducing the consumption of regenerant. (4) Anion exchange resin is less resistant to pollution by organic matter and other factors than cation exchange resin, so it is not suitable to directly pass into raw water. What effect does the pH value of water have on the removal of silicon by an anion exchanger? 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, because silicon exists in the form of silicic acid in the water. 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. Because of the high pH value, silicon exists in the form of silicate in the water, which easily generates counter ions OH-. The higher the concentration of counter ions OH-, the greater its role in hindering silicon removal. The reaction is as follows: R-OH+NaHSiO3 R-HsiO3+NaOH The reverse reaction speed of this reaction is much faster than the forward reaction speed, so the HsiO3- content in the water is high. What are the characteristics of fixed bed countercurrent regeneration ion exchanger? Answer: The biggest feature of the fixed-bed countercurrent regeneration ion exchanger is that the direction of the water flow during operation is opposite to the flow direction of the regeneration liquid during regeneration. Generally, it operates in parallel flow and regenerates in countercurrent flow. During countercurrent regeneration, the fresh regeneration fluid first contacts the resin with less failure and flows from the bottom of the exchanger to the upper part, while the poor quality regeneration fluid contacts the resin with more failure in the upper layer. According to the ion balance in the solution, the regeneration fluid can be well utilized in the lower or upper part, thus * * It greatly improves the resin regeneration rate and the economy of regeneration. When running downstream, the water to be treated enters from the upper part of the exchanger and first contacts the resin with poor regeneration. As the water flows downward, the amount of ions to be exchanged in the water gradually decreases, and the resin in contact has a higher and higher regeneration degree. According to the equilibrium relationship of ion exchange, the higher the regeneration degree of the resin in the protective layer, the greater the purity of the effluent. Therefore, the exchange resin in the fixed-bed countercurrent regeneration ion exchanger has a high degree of regeneration, low consumption of regenerant, and good effluent quality. What are the requirements for the concentration and flow rate of the regeneration solution during countercurrent regeneration of the ion exchanger? Answer: The selection of concentration takes the regeneration effect as an important condition, and the optimal concentration is obtained through adjustment experiments based on water quality and other conditions. Generally, when hydrochloric acid is used as the regenerant in cation exchangers, the regeneration concentration is mostly in the range of 2% to 5%, but lower concentrations are also used. ； When regenerating anions, most of them use NaOH solution between 0.5% and 2.5%, which has better effect. The flow rate of the regeneration fluid during regeneration is generally in the range of 4 to 6m/h. If the flow rate is too high, it will cause chaos and destroy the regeneration conditions. ； If the flow rate is too small and the regeneration time is too long, 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 a high salt content is used for backwashing, the cation (or anion) ions in the backwash water will be exchanged and adsorbed by the bottom resin, and these ions will be displaced during operation, affecting the quality of the effluent water. Therefore, it is best to use demineralized water (or softened water) for backwashing. What issues should be paid attention to during the storage and storage of ion exchange resin? Answer: During the storage and storage of ion exchange resin, the following issues should be paid attention to:: (l) When the resin is stored for a long time, it should be converted into a neutral salt form, washed with pure water, and then sealed. (2) In order to prevent the resin from cracking when drying, it is best to soak it in boiled water. The water in which the resin is soaked needs to be changed frequently to avoid breeding bacteria and contaminating the resin. (3) Once the resin is dehydrated, do not soak it in clean water. Instead, soak it in saturated salt water, and then gradually dilute the salt solution to slowly expand the resin. The recovered resin is then soaked in boiled water. (4) The resin storage temperature should not be too high, generally between 5 and 20°C, and the maximum temperature should not exceed 40OC. (5) During the storage process of resin, avoid contact with substances that may easily contaminate the resin, such as rust, strong oxidants, organic matter, grease, etc. How to identify different ion exchange resins? Answer: Take 2 mL of resin, place it in a 30 mL test tube, add 5 mL of 1 mol/L HCl solution, shake for 1 to 2 minutes, suck off the upper clear liquid with a pipette, repeat the operation 2 to 3 times, wash with distilled water 2 to 3 times, then add 4 to 5 mL of 10% CuSO4 solution, shake for 1 min, discard the upper residual liquid, and rinse with distilled water 2 to 3 times. 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 remains light green, it is a weakly acidic resin. If the resin does not change color after the above treatment, add 5 mL of 1 mol/L NaOH solution, shake for 1 min, wash with distilled water 2 to 3 times, then add 5 drops of phenolphthalein solution, and shake for 1 min. If the resin is red, it is a strongly alkaline resin. If the resin still does not change color, add 1 moI/L, 5 mL of HCI solution, shake for 1 min, wash with distilled water 2 to 3 times, then add 5 drops of methyl red solution, shake for 1 min. If the resin turns pink, it is a weakly alkaline resin. After the above treatment, if the resin still does not change color, it means that the resin has no ion exchange ability. What are the factors that affect ion exchange rate? Answer: The main factors that affect the ion exchange rate are: ①resin exchange groups ； ②Cross-linking degree of resin ； ③Resin particle size ； ④solution concentration ； ⑤water temperature ； ⑥water flow speed ； ⑦The nature of the ions being exchanged, etc. What is the unit consumption of regenerant? What is the specific consumption of regenerant? Answer: The number of grams of regenerant consumed to restore the exchange capacity of l mol of exchange agent is called the unit consumption of regenerant. When it is regenerated with table salt, it is called salt consumption. When regenerated with acid, it is called acid consumption. When alkali is used for regeneration, it is called alkali consumption. The formula for calculating unit consumption is as follows:: Specific consumption is the ratio of the actual consumption of regenerant to the theoretical consumption of regenerant, that is, specific consumption = $ Judgment: During the operation of the ion exchanger, the greater the inlet water flow rate, the greater the working exchange capacity of the exchange agent, and the greater the periodic water production volume. ( ) Answer: ×. $Brief answer: What is the working exchange capacity of an ion exchanger? What are the factors that affect the working exchange capacity? Answer: During the operation of the ion exchanger, the effective exchange capacity of the ion exchanger is called the working exchange capacity. Factors that affect the size of work exchange capacity include: ①Ion concentration of incoming water ； ②Control indicators for exchange endpoints ； ③The height of the exchange agent layer ； ④water flow rate ； ⑤water pH ； ⑥exchanger particle size ； ⑦exchange group form ； ⑧Whether the regeneration is sufficient, etc. What are the differences in the regeneration conditions of a strongly alkaline anion exchanger and a strongly acidic cation exchanger? Why? Answer: The differences are mainly reflected in the following aspects:: (l) Regenerant dosage. The regeneration specific consumption of the cation exchanger is small, while the regeneration specific consumption of the anion exchanger is large. (2) Regeneration fluid concentration. The concentration of regeneration fluid for cation exchangers is generally 3% to 5%, while the concentration of regeneration fluid for anion exchangers is generally 1.5% to 4%. (3) The temperature of the regeneration fluid and the regeneration time. There is no requirement for the regeneration liquid temperature of the cation exchanger, and the regeneration time is short. Regeneration is generally completed within 30 to 45 minutes. ； The temperature of the regeneration liquid of the anion exchanger is generally controlled at 40±5oC, and the regeneration time takes 45 to 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 are not very mobile, and its double electric layer is easily compressed. Secondly, HSiO3- is difficult to be replaced and its speed is relatively slow. How to prevent feed water pump corrosion? Answer: To prevent water pump corrosion, we should mainly focus on deoxidizing the water supply, adjusting the pH value of the water supply, and improving the material of the water supply pump. Specific measures are as follows: (l) Ensure the normal operation of the thermal deaerator, improve the oxygen removal efficiency, and combine it with the addition of hydrazine to the feed water to completely eliminate residual dissolved oxygen in the feed water. (2) Reasonably choose the material of the water supply pump. The guide vanes and impellers of the water supply pump are made of corrosion-resistant materials, such as chromium steel (2Cr13), stainless steel (lCr18Ni9Ti), etc. (3) Stabilize the quality of the supply water and perform ammoniation treatment to increase the pH value of the supply water within the range of 8.5 to 9.2. (4) Prevent air from leaking into the pump or water vaporization to avoid cavitation. How to prevent corrosion in water supply systems? Answer: The main factors causing corrosion in water supply systems are oxygen and carbon dioxide in the water. Therefore, preventing corrosion of the water supply system should start by eliminating oxygen and carbon dioxide in the water. At present, various power plants mainly take the following measures:: (1) Deoxygenate the water. Thermal deoxidation is mainly used, that is, steam heating is used to heat the water to the boiling point under the corresponding pressure, so that the dissolved oxygen in the water is analyzed. At the same time, it is supplemented by chemical deoxidation, that is, adding hydrazine to the water to completely eliminate the residual oxygen in the water. (2) Add ammonia to the water supply. The alkalinity produced by ammonia dissolved in water is used to increase and adjust the pH value of the water supply, and control it between 8.5 and 9.2, so that a stable protective film is formed on the metal surface, thereby preventing corrosive media from corroding the metal of the water supply system. In addition, the volatility of ammonia can be used to make the pH value of the condensate water greater than 8, preventing carbon dioxide corrosion of the condensate water system. (3) Reduce the carbonate alkalinity of the supply water. Generally, water can be softened by H-Na, and acid and chemical desalination can be used to soften the water to reduce the carbonate alkalinity in the water to less than 0.01m mol/L. Why do we need to carry out anti-corrosion work on out-of-service boilers? Answer: There are salt, scale, slag, etc. on the metal surface of the shutdown boiler. Corrosion will occur if it comes into contact with O2 and CO2 in the air. This type of corrosion is much more serious than corrosion during operation. When the economizer is running, the inlet part is generally susceptible to corrosion. If no anti-corrosion work is done on the standby boiler, the entire pipeline will be corroded. Generally, corrosion does not occur in the superheater during operation, but corrosion may occur when it is shut down, especially in the elbow part. Boiler water wall tubes and steam drums rarely suffer from oxygen corrosion during operation, but are extremely prone to oxygen corrosion when shut down. Corrosion occurs during shutdown. On the one hand, corrosion products in the water are increased. At the same time, these corrosion products such as Fe2O3 CuO are corrosion accelerators. This is an important reason for corrosion and scaling during operation. Therefore, we must pay attention to anti-corrosion when shutting down standby boilers. What are the basic principles for anti-corrosion of standby boilers? Answer: There are many ways to prevent corrosion of standby boilers, but the basic principles are as follows:: (l) Prevent air from entering the water and vapor system of the standby boiler. Such as maintaining a certain steam pressure or feed water pressure in the boiler. (2) Keep the metal surfaces of boiler equipment for shutdown fully dry. For example, the method of hot and pressurized water release, using the waste heat of the furnace for drying or using the hot air drying from an adjacent operating boiler, etc. Practice has proved that when the relative humidity inside the shutdown boiler equipment is less than 20%, corrosion can be prevented. (3) Form a protective film or adsorption film with anti-corrosion effect on the metal surface. For example, after shutting down the furnace and draining the water, use gas-phase corrosion inhibitors (such as cyclohexylamine carbonate) to prevent corrosion. (4) Soak the metal surface in an aqueous solution containing oxygen scavenger or other protective agent. Such as soaking in hydrazine or ammonia solution. (5) Fill inert gas into the shutdown boiler equipment. Such as filling with high-purity nitrogen or ammonia. In fact, the above principles can be summarized as three aspects to prevent electrochemical corrosion: starting from removing the cathode depolarizing agent to polarize the cathode, or forming a stable protective film or adsorption film to polarize the anode, or making the metal surface free of electrolyte solution. How to choose the protection method for shutting down the standby boiler? Answer: When choosing a protection method for a standby boiler, the following main issues should be considered based on specific conditions: ① Structural form of the boiler body ； ②The length of downtime ； ③ambient temperature ； ④On-site equipment conditions ； ⑤Source and quality of water, etc. What causes iron oxide scale to form? What are its characteristics? Answer: Iron oxide scale is currently the most common type of scale in water-cooled wall tubes of boilers in thermal power plants. The main reason for its formation is: The local heat load on the boiler heating surface is too high ； Boiler water contains large amounts of iron ； Poor boiler water circulation ； There are more corrosion products on the metal surface, etc. Iron oxide scale is generally in the shape of shells, and some are in the form of scaly protrusions. The surface of the scale layer is brown, and the inside and bottom are black or gray. After the scale layer peels off, there will be a small amount of white substances on the metal surface. These white substances are mainly compounds of silicon, calcium, magnesium and phosphate. Some scales also contain a small amount of sodium hydroxide. The biggest characteristic of iron oxide scale is that the metal surface under the scale layer is corroded to varying degrees, ranging from pitting and ulcers to perforations. How to prevent iron oxide scale in boilers? Answer: To prevent the occurrence of iron oxide scale in boilers, we should start from the following aspects:: (l) Newly installed boilers must be chemically cleaned. Remove impurities such as rolled skin, welding slag and corrosion products in boiler equipment. (2) Minimize the oxygen and iron content of the water supply. (3) Improve the dosing treatment in the boiler and strengthen the boiler sewage discharge. (4) When the unit is started, strictly monitor the water quality in the boiler water circulation system, such as strengthening drainage and water changes. (5) Carry out anti-corrosion work during equipment outage or maintenance. In addition, in terms of boiler structure and operation, excessive local heat load on the metal on the heating surface should be avoided to maintain normal combustion and good water circulation conditions of the boiler in operation. How does copper scale form on the heating surface of the boiler? How to prevent it? Answer: The copper scale on the heating surface of the boiler is mainly caused by the electrochemical process of reducing copper oxide into metallic copper with the feed water into the boiler. This process has nothing to do with the pressure of the boiler. It mainly occurs in areas where the heat load on the heating surface is too high. The oxide film on the metal surface is destroyed 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 to form metallic copper and precipitate on the tube wall. The amount of copper precipitation increases with the increase in boiler heat load. The electrochemical process is as follows: Fe-→Fe2++2e Cu2++2e-→Cu To prevent the formation of copper scale, two aspects should be considered: First, try to prevent corrosion of copper parts of thermal equipment and reduce the copper content in water supply ； Second, in terms of boiler operation, try to avoid excessive local heat loads. What is the phenomenon of "temporary disappearance of salts" in boiler water? What are its hazards? Answer: When the drum boiler load increases, some soluble sodium salts in the boiler water precipitate from the boiler water and deposit on the furnace tube wall, making their concentration in the boiler water significantly reduced. When the boiler load decreases or the boiler is shut down, the sodium salts deposited on the tube wall are dissolved again, causing their concentration in the boiler water to increase again. This phenomenon is called the "temporary disappearance of salts" phenomenon, also known as the "salt hiding" phenomenon. "The hazards of the "salt hiding" phenomenon are similar to those 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 turn into insoluble scale. (2) Poor heat transfer performance can lead to overheating, deformation and even explosion of furnace tube metal. (3) Can cause metal corrosion under sediments. How to prevent the phenomenon of "temporary disappearance of salts" in boiler water? Answer: To prevent the phenomenon of "temporary disappearance of salts" in boiler water, the following measures should generally be taken: (l) Improve the combustion conditions of the boiler and make the heat load on each part of the furnace tube uniform ； Prevent coking and slagging in the furnace and avoid excessive local heat load on the furnace tube. (2) Improve the boiler water flow conditions in the boiler tubes to ensure the normal operation of the water cycle. For example, cancel the horizontal evaporation tube and increase the inclination of the furnace tube to more than 15°C to 30°C. (3) Improve the dosing treatment in the boiler and limit the phosphate content in the boiler water. Such as using low phosphate treatment or pure phosphate treatment. (4) Reduce sediments in boiler tubes and improve their cleanliness, etc. What is a corrosion inhibitor? What are its characteristics? Answer: During the boiler pickling process, a small amount of certain chemicals are added to the pickling solution to inhibit or slow down the corrosion of the metal by the pickling solution. This chemical is called a corrosion inhibitor. The characteristics of corrosion inhibitors are as follows: (l) Adding a very small amount (a few parts per dry part or a few parts per 10,000) can * * Reduce the corrosion rate of pickling liquid on metals ； (2) It will not reduce the ability of the pickling solution to remove sediments ； (3) Its ability to inhibit corrosion will not be reduced as cleaning time passes. ； (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 slow down corrosion? How to choose corrosion inhibitors during pickling? Answer: The reason why corrosion inhibitors can slow down corrosion is due to the following two aspects:: (l) Corrosion inhibitor molecules are adsorbed on the metal surface to form a very thin protective film, thereby inhibiting corrosion. (2) The corrosion inhibitor reacts with the metal surface or other ions in the solution, and the reaction products cover the metal surface to inhibit corrosion. Determining the type and amount of corrosion inhibitor during pickling is related to the type and concentration of the cleaning agent. In addition, it is also related to the cleaning temperature and flow rate, because each corrosion inhibitor has its suitable temperature and flow rate range. The effect of corrosion inhibitors in reducing the corrosion rate generally decreases as the temperature of the cleaning fluid increases and the flow rate increases. Due to the influence of many factors, the selection of corrosion inhibitors should be determined through small experiments. Why does "copper plating" occur when running boiler pickling? What are its hazards? How to eliminate it? Answer: When operating boiler pickling, if the copper content of the deposits in the operating boiler is high, the pickling liquid and the deposits containing more copper will react according to the following formula: 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 surface of the steel to be unevenly plated with metallic copper. Since the electrode potentials of copper and iron are different, when copper and iron come into contact, a corrosion battery is formed, which can cause severe pitting corrosion of the metal being cleaned. To eliminate the "copper plating" phenomenon during the pickling process, the following measures can be taken: (1) When the CuO content in the sediment in the boiler is less than 5%, a masking agent can be added to the cleaning solution to remove copper. ； (2) When the CuO content in the sediment in the boiler exceeds 5%, during the pickling process, it is necessary to consider adding an ammonia washing step. The copper ions generate stable copper ammonia complex ions in ammonia water to prevent the occurrence of "copper plating" phenomenon. After boiler pickling, why do we need to rinse with dilute citric acid solution? Answer: The purpose of rinsing with citric acid is to use the complexing properties of citric acid and iron ions to remove residual iron ions in the pickling system and secondary rust that may be generated during rinsing after pickling, providing more favorable conditions for passivation treatment. In addition, the rinsing time after pickling can be shortened and water consumption can be reduced. What is corrosion under deposits in a boiler? How to prevent it? Answer: When scale, slag or metal corrosion products adhere to the metal surface in the pot, severe corrosion will occur underneath it. This corrosion is called corrosion under the sediment in the boiler. This kind of corrosion is related to the local concentration of boiler water, so it is also called medium concentration corrosion. To prevent this kind of corrosion, the following measures are generally taken:: (1) Necessary chemical cleaning should be carried out for newly installed boilers or boilers after operation. (2) Do a good job in anti-corrosion of the water supply system and reduce the copper and iron content in the water supply. (3) Carry out anti-corrosion work on the boiler that is in standby mode to prevent corrosion in the boiler during the standby period. (4) Improve the quality of feed water to minimize the corrosive components brought into the boiler by the feed water. (5) Choose a reasonable boiler water treatment method to adjust the boiler water quality and eliminate or reduce corrosive impurities in the boiler water. What is coordinated pH-phosphate treatment? Answers: Coordinated pH-Phosphate treatment is a strict and reasonable method of regulating water quality in the pot. It can not only prevent the generation of calcium and magnesium scale, but also prevent the corrosion of boiler tubes. This treatment essentially involves adding different proportions of phosphates, namely trisodium phosphate and disodium hydrogen phosphate (or sodium dihydrogen phosphate) into the pot according to the hardness and alkalinity of the water supply. The main purpose of adding disodium hydrogen phosphate or sodium dihydrogen phosphate is to neutralize the free sodium hydroxide brought into the boiler water by the feed water. The reaction is as follows: Na2HPO4 + NaOH → Na3PO4 + H2O. Trisodium phosphate in water can establish a hydrolysis equilibrium according to the following formula: Na3PO4 + H2O Na2HPO4 + NaOH Therefore, the trisodium phosphate added at this time can not only maintain a certain amount of excess phosphate in the boiler water, but also can produce a certain amount of sodium hydroxide due to its hydrolysis, and can also maintain the pH value of the boiler water. When the boiler water is locally evaporated and concentrated, the hydrolysis balance moves in the direction of generating trisodium phosphate, which will not concentrate the sodium hydroxide to a level that is harmful to the metal. Even under high heat loads, it can prevent the metal from being corroded by concentrated alkali. What is the boiler's blowdown rate? How to calculate the boiler's blowdown rate? Answer: The percentage of the boiler's sewage discharge per unit time to the boiler's evaporation is called the boiler's sewage discharge rate. That is, P= where DP--boiler wastewater volume, t/h ； D--boiler evaporation capacity t/h ； P--boiler blowdown rate,%. The calculation of the boiler blowdown rate is generally not calculated according to the above formula, but based on the principle that the amount of salt brought into the boiler by the feed water is equal to the sum of the amount of salt discharged by the boiler blowdown and the amount of salt taken away by the saturated steam (i.e., the salt balance principle). The calculation formula derived is as follows: p=- ×100% where P is - the salt content or silicon content in the feed water, mg/L ； P furnace--salt content or silicon content in furnace water, mg/L ； P steam - salt content or silicon content in saturated steam, mg/L ； P--boiler blowdown rate, %. What effect does the salt content of boiler water have on steam quality? Answer: When the salt content of boiler water does not exceed a certain value, it has basically no impact on steam quality. However, when the salt content of boiler water exceeds a certain value, the impact on steam quality increases significantly. (1) As the salt content of boiler water increases, its viscosity increases, making it difficult for the water bubbles in the water layer to merge into large bubbles. Therefore, the water chamber of the steam drum is filled with small bubbles, and the small bubbles rise slowly in the water. As a result, the water level expands intensified and the height of the steam space is reduced, which is not conducive to the separation of steam and water. (2) When the impurity content in boiler water increases to a certain level, a foam layer will be formed at the interface between steam and moisture. The foam layer will reduce the height of the steam space and affect the separation of steam and water. When the foam layer is too high, steam can directly take away the foam, causing the steam to carry a large amount of water. When the salinity content of boiler water increases to a certain level, these two factors will deteriorate the steam-water separation effect, and the steam will carry a large amount of water, causing a sharp increase in the salinity content of the steam. What impact does the operating condition of the boiler have on steam quality? Answer: The operating conditions such as the load of the boiler, the speed of load change and the drum water level have a great impact on the 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 between water droplets splashing to the steam outlet pipe, which is not conducive to natural separation and will increase the amount of water carried by the steam. (2) Boiler load. When the boiler load increases, because the kinetic energy of the steam-water mixture increases, the amount and kinetic energy of water droplets formed by mechanical impact and splash also increase. In addition, the flow rate of steam out of the drum increases and the flow rate accelerates. Therefore, the ability of steam to carry moisture increases, and the amount of water carried by steam also increases. (3) Changes in boiler load, water level, pressure, etc. If the load, water level, and pressure of the boiler change too drastically, the steam will also carry a large amount of water. For example: When the boiler load suddenly increases and the pressure drops suddenly, the boiler water will boil rapidly due to the drop in the boiling point of water, producing a large number of steam bubbles. This will cause the bubbles to burst and produce a large number of small water droplets, and the water level will also expand. * * intensified. Reduce the steam space. These will cause an increase in the amount of water carried by the steam and increase the salt content of the steam. What are the rules for dissolving and carrying impurities in saturated steam? Answer: Saturated steam dissolves and carries impurities according to the following rules:: (l) The ability of saturated steam to dissolve carried impurities is related to boiler pressure. The greater the pressure, the greater the dissolution and carrying capacity. (2) Saturated steam dissolves and carries impurities selectively. Saturated steam has different dissolving abilities for various substances. For example, common substances in boiler water can be divided into three categories according to their dissolving abilities in saturated steam.: The first type is silicic acid (H2SiO2, H2Si2O3, H4SiO4, etc.), which has the largest solubility ； The second category is NaCl, NaOH, etc., which have much lower solubility than silicic acid. ； The third category is Na2SO4, Na3PO4 and Na2SiO3, etc., which are difficult to dissolve in saturated steam. (3) The dissolved carrying capacity increases with the increase of pressure. Because as the saturated steam pressure increases, the density of the steam also increases, and the amount of dissolved substances in it also increases. (4) Saturated steam has special properties in dissolving silicon compounds. The state of silicon compounds in boiler water is divided into: Dissolved silicate and solution silicic acid, saturated steam dissolves and carries mainly solution silicic acid, and has very little ability to dissolve silicate. How are salt deposits distributed in 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 less soluble these impurities are, so they are deposited in the superheater (or carried as solid particles by the steam to the turbine). (2) NaOH. The higher the temperature, the greater the solubility, so it is carried to the turbine as concentrated droplets. However, the concentrated NaOH droplets also adhere to the superheater tube wall, react with CO2 to generate Na2CO3, and are deposited in the superheater. (3) NaCl. When the pressure is greater than 9.8MPa, its solubility is very high, and it is often dissolved in superheated steam and taken to the turbine. (4) H2SiO3 or H4SiO4. Both lose water and become SiO2. SiO2 has a high solubility in superheated steam and is generally brought to the steam turbine. Therefore, the deposition of salt substances in the superheater is summarized as follows: (l) The deposits in the superheaters of medium and low pressure boilers are mainly sodium compounds (Na2SO4, Na3PO4, Na2CO3 and NaCl, etc.). (2) The sediments in the high-pressure boiler superheater are mainly Na2SO4 and Na3PO4, with very little other sodium salt content. (3) The amount of salt deposits in the superheater of the ultra-high pressure boiler is very small. What causes deposits to form in steam turbines? What are its characteristics? Answers: The reasons for the formation of deposits in steam turbines are as follows:: (l) During the process of superheated steam doing work in the steam turbine, its pressure and temperature gradually decrease, and the solubility of sodium compounds and silicic acid in the steam also decreases, so they are deposited in the steam turbine. (2) Tiny concentrated NaOH droplets and some solid particles in the steam adhere to the steam passage part of the steam turbine to form deposits. The deposition characteristics of various impurities in steam turbines are as follows:: (l) Sodium compounds are deposited in the high-pressure section of the turbine. (2) Silicic acid is dehydrated into quartz crystals and deposited in the middle and low pressure sections of the steam turbine. (3) Iron oxides can be deposited on blades at all stages of the steam turbine. What is the distribution of salt deposits in the turbine? Answer: The distribution of salt deposits in the steam turbine is as follows: ①The amount of sediment in different levels varies ； ②The chemical composition of sediments in different levels is different ； ③Uneven distribution on separators and impellers at all levels ； ④The amount of deposits in heating units and units that frequently start and stop is very small. What specific steps should be taken to obtain clean steam? Answer: To obtain clean steam, the following measures must be taken: (l) Minimize the impurities entering the boiler water. Specific measures include: ①Improve supply water quality ； ②Reduce makeup water rate ； ③Prevent corrosion in water supply systems ； ④Chemically clean the boiler promptly. (2) Strengthen the blowdown of boilers. Carry out continuous and regular sewage discharge work. (3) Improve the internal devices of the steam drum. Including improved 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, pressure and temperature of saturated steam, avoiding excessive changes in operating parameters, reducing the salt content of the boiler water, etc. What is the thermochemical test of a drum boiler? What is the purpose of the thermochemical test? Answer: The thermochemical test is to determine the reasonable boiler water quality standards and the boiler operation mode that ensures good steam quality by adjusting the salt content of the boiler water and changing the boiler operating parameters. In other words, it is a specialized test of the boiler's characteristics and water quality conditions. The purpose of thermochemical testing is to determine the relationship between water quality, steam quality, boiler thermal process, boiler operating conditions, and equipment characteristics through testing. ； When the steam quality is good, determine the boiler water quality standards and the best operating conditions of the boiler. Under what circumstances does a boiler need to undergo thermochemical testing? Answer: Thermochemical tests must be carried out under the following circumstances: ①After the newly installed boiler is put into operation for a period of time ； ②Modified boiler ； ③When the boiler operating mode changes, such as a major change in the feed water composition or feed water quality ； Combustion conditions change ； Increase rated evaporation capacity ； Change the water treatment method in the boiler, etc. ④Salt accumulation in the superheater and turbine occurs due to poor steam quality. What is stress corrosion? What are the characteristics of stress corrosion? Answer: The corrosion of metal materials under the action of stress and corrosive media is called stress corrosion. The characteristics of stress corrosion are: The fracture is a brittle fracture, which is different from mechanical fracture. There are many cracks around the fracture, and most cracks develop from the media contact surface to the metal matrix. Depending on the material and medium, cracks may develop along the crystal edge or across the crystal. Generally speaking, ordinary steel suffers from corrosion along the crystal edge. ； Austenitic steel suffers from transgranular corrosion. How to determine whether attachments have formed on the inner wall of the copper tube of the condenser? Answer: After attachments are formed on the inner wall of the copper tube of the condenser, the following symptoms usually occur:: (l) The water flow resistance in the system increases. Under the same water flow rate, the flow resistance of the condenser with attachments is significantly higher than that of the condenser with clean copper tubes. (2) The cooling water flow rate decreases. As the resistance of the cooling water system increases, the flow rate of the cooling water decreases when the cooling water pressure remains unchanged. (3) The temperature at the outlet increases. Due to the poor thermal conductivity of the attachment, the cooling water outlet temperature and the turbine exhaust temperature increase. (4) The vacuum degree of the condenser decreases. Each of the above reasons will cause the temperature of the condensed water in the condenser to increase and the vacuum degree of the condenser to decrease. In the production practice of thermal power plants, when the electrical load and thermal load of the steam turbine generator unit are the same, the decrease in vacuum degree of the condenser is often used to determine the amount of attachments generated inside it and whether it needs to be shut down for cleaning. How to determine whether there is scaling in the copper tubes of the condenser? Answer: Whether there is scaling in the copper pipe can be judged based on the results of water quality analysis. (l) Judgment based on the concentration rate of salts in the cooling water. If HT, cold, HT, supplement in the formula - are the carbonate hardness of cooling water and supplementary water respectively ； Cold and supplementary water - are the chloride ion content of cooling water and supplementary water respectively. It means that the water has not been scaled in the recent period. If it does, it means that the decomposition of bicarbonate has occurred in the cooling water system, and scaling has occurred. If the cooling water is chlorinated, the cold and supplementary conditions can be changed to cold and supplementary. (2) Judgment by measuring the stability of cooling water. If A before = A after or PH before = PH after, in the formula, A before and A after - are the alkalinity before and after water passes through the marble, respectively. ； Pre-PH, post-PH - are the pH values ​​before and after water passes through the marble, respectively. This means that no scaling occurs in the cooling water system. If pre-A > post-A or pre-PH > post-PH, it means there is a tendency for scaling in the cooling water system. What are the forms of corrosion in condenser copper tubes? Answers: The corrosion of copper tubes in condensers varies depending on factors such as the structure, material, usage conditions and cooling water quality of the condenser, and its corrosion forms are diverse. Generally common ones include the following: ①ulcer erosion ； ②impact corrosion ； ③Dezincification corrosion ； ④hot spot corrosion ； ⑤stress corrosion ； ⑥corrosion fatigue ； ⑦Ammonia corrosion on the steam side ； ⑧Corrosion caused by cooling with contaminated seawater, etc. Under what circumstances is dezincification corrosion likely to occur in condenser copper tubes? How to prevent it? Answer: Condenser copper tubes are prone to dezincification corrosion under the following conditions:: (l) The copper alloy composition contains impurities. If copper and zinc alloys contain iron, it will offset the inhibitory effect of arsenic on dezincification and accelerate the dezincification corrosion of brass tubes. In addition, slag inclusions in the brass tube alloy will cause serious dezincification corrosion there. (2) The cooling water is contaminated. After the cooling water is contaminated, corrosive substances in the water increase, which reduces the anti-dezincification ability of arsenic in the brass tube. Even if the brass tube contains more than 0.03% arsenic, dezincification corrosion will occur. (3) The flow rate of cooling water is too slow. (4) The condenser tube wall temperature is too high. (5) There are permeable attachments on the internal surface of the copper pipe. To prevent dezincification corrosion of condenser copper tubes, the following measures can be taken:: (l) Select different arsenic-containing copper pipes according to the quality of the cooling water. (2) Reduce the tube wall temperature of the condenser. (3) Increase the flow rate of water in the tube to prevent the cooling water from stagnating in the tube for a long time. (4) The surface of the copper pipe is coated with ferrous sulfate. What is stress corrosion of copper pipes? What are the factors that cause it? How to prevent it? Answer: Under the action of stress (especially tensile stress) and corrosive media, corrosion cracks will appear along the grain boundaries over time, causing damage to the pipe. This phenomenon is called stress corrosion. The stress corrosion of copper pipes is not only related to the effect of stress, but also related to many other factors. Under the action of seat force, substances such as oxygen, ammonia and hydrogen sulfide in the water are important factors that promote stress corrosion. To prevent stress corrosion of copper pipes, the following measures are generally taken:: (l) Care should be taken to avoid stress during the manufacturing, transportation and assembly processes of copper pipes. When stress is present, anneal before use. (2) Prevent the copper pipe from vibrating during operation. (3) Select appropriate copper pipe materials. (4) The arsenic content of aluminum brass should not be too high. How to check the leakage of condenser copper pipe during operation? Answer: The most common methods to check condenser copper tube leakage during operation are as follows:: (l) Thin film method. The specific method is to press a thin film with a thickness of 0.02 to 0.03 mm on both ends of the condenser tube sheets during the half-side inspection of the steam turbine with reduced load. Since a vacuum will be formed in the leaking tube, the leaking tube can be detected based on the film at the tube mouth sucking inward. (2) U-shaped tube water level method. During the half-side inspection of the steam turbine with reduced load, open the large covers at both ends of the condenser, block the nozzle at one end, and insert a U-shaped glass tube with a rubber plug and filled with colored liquid into the nozzle at the other end. When the tube leaks, a liquid level difference will occur in the U-shaped tube. In order to shorten the leak finding time, a water level meter can be installed in the condenser water chamber, and the cooling water can be slowly discharged to observe changes in the conductivity of the condensed water. After initially determining the leakage location, a U-shaped tube can be used to determine the specific leakage location. (3) Candle method (or smoke method). When inspecting the half-side inspection of the steam turbine with reduced load, open the large covers at both ends of the condenser, block the pipe opening at one end, and slowly move a lit candle or cigarette along the pipe opening at the other end. The leaking pipe will suck fire or smoke in due to the vacuum, and the leaking pipe can be detected. You can also combine this question (2) to drain the water in the water chamber. After initially determining the location, use this method to determine the specific leakage location. (4) Fluorescence method. During the half-side inspection of the steam turbine with reduced load, 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. In order to make the fluorescent liquid seep out from the leakage quickly, a certain pressure can be added to the steam side, and after half an hour, use a light source to illuminate it. When irradiating, move it horizontally from top to bottom, and the fluorescent liquid will emit yellow-green light at the leakage point. (5) Instrumental method. For example, use an ultrasonic leak detector to detect leaks. If a condenser leak is found during operation of the steam turbine, what should be done? Answer: If a condenser leak is found, the following measures can be taken according to the degree of deterioration of the condensate water quality.: (1) When the hardness of the condensate water of the high-pressure unit is greater than 2 μmo1/L, and the hardness of the condensate water of the medium-pressure unit is greater than 3 μmo1/L, due to slight leakage, sawdust can be added to the cooling water inlet for treatment. If the water quality deteriorates due to loose expansion of the copper pipe, the turbine operator may be advised to increase the exhaust chamber temperature or reduce the cooling water pressure to reduce the amount of leaking water. (2) If the leakage lasts for a long time and the condensate water quality still does not improve after the above treatment, you can stop adding sawdust, reduce the load of the steam turbine, and conduct a half-surface inspection of the condenser. Find the leakage point and plug it before putting it into operation. (3) If the quality of condensate water deteriorates seriously and affects the quality of water supply, effective measures can be taken according to the specific conditions 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 amount of boiler sewage discharge. If necessary, stop the machine to repair leaks. How to prevent corrosion on the cooling water side of the condenser copper tube? Answer: To prevent corrosion of the condenser copper tubes, water purification cannot be used because the flow rate of cooling water is too large. Generally, methods such as selecting appropriate pipe materials, forming a film on the surface of the copper pipe, and adding certain chemicals to the water are used. The specific measures are as follows.: (l) According to the quality of the cooling water, rationally select the condenser copper tube materials. (2) Do a good job in maintenance, processing and installation of copper pipes before they are put into operation. (3) The surface of the copper pipe is treated with ferrous sulfate film formation. (4) Cathodic protection is used for the copper tubes of the condenser in operation. (5) Install a protective sleeve or apply epoxy resin glue on the end of the copper pipe. (6) Carry out water quality stabilization treatment on cooling water. $The following figure is a structural diagram of a floating bed ion exchanger. Point out the names of the components shown in the figure. Answer: 1-Inert resin 2-Upper distribution device 3-In vivo sampling device 4-Water cushion 5-Lower distribution device 6-Water retaining layer Try to draw the change curve of the outlet water quality of the strongly alkaline OH type exchanger. Answer: Try to draw a diagram of the dosing system of boiler phosphate solution. Answer: Try to draw the structure diagram of a two-flow filter. Answer: Try to draw the answer to the diagram of the first-level complex bed plus mixed bed system: Draw its three views based on the axonometric drawing below. Answer: According to the three-view projection relationship, fill in the missing lines in each view in the figure below. Answer: Draw a third supplementary drawing based on the two views (reference axonometric drawing). Answer: Draw a schematic diagram of the operating system of a coverage filter. Answer: