Isolation method of condenser

Abstract

The invention provides an isolation method for a condenser, and relates to the technical field of circulating water of thermal power generating units, which comprises the following steps of: performing isolation operation on circulating water on one side of the condenser: firstly reducing unit load and keeping a vacuum pump running; sequentially operating the circulating water pump and each electric door, and opening the door for maintenance after water is drained off; monitoring parameters during the period and paying attention to the vacuum pump state; and working water overtemperature contact maintenance is carried out. After isolation, the system can be recovered according to steps, stable operation of the unit is ensured, and the problems that leakage faults often occur in the condenser of the thermal power plant, and check treatment is often needed after shutdown when leakage occurs in the condenser are solved. A condenser is divided into a circulating water side and a steam side, the circulating water side needs to be isolated during leakage generally, the circulating water side needs to have water all the time during operation of a unit, otherwise, the problems that the circulating water is cut off, the steam discharged into the condenser cannot be cooled, and the vacuum low tripping of the unit and the expansion and damage accidents of the condenser occur can be solved.

Description

Technical Field

[0001] The invention belongs to the technical field of circulating water of thermal power units, and more specifically, particularly relates to a condenser isolation method. Background Art

[0002] Condensers in thermal power plants often leak. When a condenser leaks, it is often necessary to shut down the unit for inspection and treatment. The condenser is divided into a circulating water side and a steam side. Generally, when a leak occurs, the circulating water side needs to be isolated. The circulating water side needs to have water all the time during the operation of the unit. Otherwise, the circulating water will be cut off and the steam discharged into the condenser cannot be cooled, resulting in the unit vacuum low tripping and condenser expansion and damage accidents. Summary of the invention

[0003] In order to solve the above technical problems, the present invention provides a condenser isolation method to solve the problems raised by the background technology.

[0004] The isolation method of the condenser of the present invention is achieved by the following specific technical means:

[0005] A method for isolating a condenser comprises the following steps:

[0006] Step 1: Preparations before isolating the circulating water on the A side of the condenser:

[0007] 1. Reduce the unit load to below 750MW.

[0008] 2. Keep two vacuum pumps running.

[0009] Step 2: Condenser A side circulating water isolation operation

[0010] Step 3: Start one circulating water pump, stop the auxiliary pump, keep two circulating water pumps running; release the standby interlock of the third circulating water pump.

[0011] Step 4: Comprehensively record the monitoring parameters of the condenser circulating water system, vacuum system, and TSI. When half of the condenser circulating water side is isolated, record the above parameters every 30 minutes.

[0012] Step 5: Gradually close the circulating water inlet electric door on the A condenser side and pay attention to the changes in the condenser vacuum.

[0013] Step 6: When the condenser vacuum is higher than -87.5 kPa and stable, gradually close the circulating water outlet electric door on the B condenser side until it is fully closed, and pay attention to monitor the changes in the circulating water system, vacuum system and TSI parameters.

[0014] Step 7: After the unit runs stably, open the vent valves of the circulating water chamber on the A side of condenser and the circulating water chamber on the B side of condenser, open the drain gate of the circulating water connecting pipe of the water chamber on the A side of condenser, the drain gate behind the circulating water inlet gate on the A side of condenser, and the drain gate before the circulating water outlet gate on the B side of condenser, start the condensate pit sewage pump, and closely monitor the changes in the condensate pit water level.

[0015] Step 8: When the vacuum and main engine parameters are stable and within the limit, after the circulating water on the A side of the condenser is drained, the circulating water inlet electric door on the A condenser side and the circulating water outlet electric door on the B condenser side are powered off, and the manhole door on the water side of the condenser is opened for maintenance. Pay attention to the changes in the condenser vacuum when opening the manhole door.

[0016] Step 9: During the shutdown of the circulating water on one side of the condenser, monitor the current of the mechanical vacuum pump, the water level of the steam-water separator of the vacuum pump group, and the changes in the working water temperature. When the working water temperature is higher than 40°C, contact maintenance to clean the working water cooler.

[0017] Step 10: Restoration of the system after isolation.

[0018] Furthermore; during the maintenance process in step nine, the vacuum is maintained not lower than -87.5kPa and the exhaust temperature does not exceed 80°C, otherwise the load continues to be reduced, and the normal operation mode is restored after the personnel are evacuated; during the leakage detection process on the condenser half side, the small machine operating parameters of the A and B condensers are closely monitored to be normal, the exhaust pressure of the small machine shall not be higher than -70kPa, and when the exhaust temperature of the small machine is higher than 85°C, check that the water spray solenoid valve of the rear cylinder of the small machine is open.

[0019] Furthermore, in step five, when the vacuum drops to -90kPa, stop the operation, report the value, continue to reduce the load of the unit, and continue to operate to full closure after the vacuum stabilizes. When the load drops below 500MW, the boiler is put into oil gun for combustion assistance.

[0020] Furthermore, in step nine, when the exhaust temperature of the low-pressure cylinder is higher than 47°C, water is sprayed into the low-pressure cylinder in a timely manner.

[0021] Further: keep the vacuum not lower than -87.5kPa, the exhaust temperature not higher than 80℃, the function is:

[0022] L=f(V,T)

[0023] When V<-87.5 and T<=80,

[0024] L=0(indicates no need to reduce load)

[0025] When V<-87.5 and T>80,

[0026] L = k1*(T-80) (where k1 is a coefficient determined according to actual conditions)

[0027] When V>=-87.5,

[0028] L = k2*(-87.5-V) (k2 is also a coefficient determined according to actual conditions)

[0029] For example, if k1=5 and the current exhaust steam temperature is 90°C, the load reduction L=5*(90-80)=50.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] 1. In this device, this condenser isolation method has the following beneficial effects:

[0032] 1. Safe and reliable operation

[0033] 1. By reducing the unit load to below 750MW and keeping the two vacuum pumps running, stable initial conditions were created for the condenser isolation operation, reducing the risks that might arise during the operation.

[0034] 2. Gradually close the operating mode of the circulating water inlet and outlet electric doors on one side of the condenser, so as to closely observe the changes in the condenser vacuum and adjust the operation in time to ensure that the vacuum is stable within a safe range. For example, when the vacuum drops to -90kPa, stop the operation and report to the supervisor, which further ensures the safety of the operation.

[0035] 3. During the period when the circulating water on one side of the condenser is out of service, monitor the current of the mechanical vacuum pump, the water level of the steam-water separator of the vacuum pump group, and the changes in the working water temperature, so as to promptly discover problems and contact maintenance to clean the working water cooler, thereby ensuring the normal operation of the vacuum pump and maintaining the vacuum state of the condenser.

[0036] 2. Proper equipment protection

[0037] 1. When isolating the condenser, comprehensively record the monitoring parameters of the condenser circulating water system, vacuum system, and TSI, and record the parameters when half of the side is isolated every 30 minutes, which helps to grasp the operating status of the equipment in a timely manner and provide data support for the safe operation of the equipment.

[0038] 2. During the maintenance process, the vacuum should be maintained at not less than -87.5kPa, and the exhaust temperature should not exceed 80℃. Otherwise, the load should continue to be reduced, and the normal operation mode should be restored after the personnel are evacuated, which effectively protects the equipment from damage caused by excessive temperature and pressure. At the same time, the exhaust pressure of the small machine should not be higher than -70kPa. When the exhaust temperature of the small machine is higher than 85℃, the solenoid valve of the water spraying in the rear cylinder of the small machine should be checked to be open, and when the exhaust temperature of the low-pressure cylinder is higher than 47℃, the low-pressure cylinder should be sprayed with water in time. These measures have played a good protective role in the equipment.

[0039] 3. Improve maintenance efficiency

[0040] 1. Clear operating steps and parameter control requirements enable maintenance personnel to carry out maintenance work in a safe environment. After a power outage, open the manhole door on the water side of the condenser for maintenance. The operation process is clear, which is conducive to improving maintenance efficiency.

[0041] 2. The recovery steps of the system after isolation are clear, which ensures that the equipment can be put into operation quickly after maintenance, reduces equipment downtime and improves the availability of the unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0043] In the figure, the corresponding relationship between the component names and the figure numbers is as follows:

[0044] 1. A condenser;

[0045] 101. Electric door for circulating water inlet;

[0046] 2. B condenser;

[0047] 201. Electric door for circulating water outlet. DETAILED DESCRIPTION

[0048] The present invention will be further described below in conjunction with specific embodiments, and the advantages and features of the present invention will become clearer as the description proceeds. However, these embodiments are exemplary only and do not constitute any limitation to the scope of the present invention. It should be understood by those skilled in the art that the details and forms of the technical solution of the present invention may be modified or replaced without departing from the spirit and scope of the present invention, but these modifications and replacements all fall within the scope of protection of the present invention.

[0049] Example:

[0050] As attached Figure 1 To Attachment Figure 1 As shown:

[0051] The present invention provides a condenser isolation method, comprising the following steps:

[0052] Step 1: Preparations before isolating the circulating water on the A side of the condenser:

[0053] 1. Reduce the unit load to below 750MW.

[0054] 2. Keep two vacuum pumps running.

[0055] Step 2: Condenser A side circulating water isolation operation

[0056] Step 3: Start one circulating water pump, stop the auxiliary pump, keep two circulating water pumps running; release the standby interlock of the third circulating water pump.

[0057] Step 4: Comprehensively record the monitoring parameters of the condenser circulating water system, vacuum system, and TSI. When half of the condenser circulating water side is isolated, record the above parameters every 30 minutes.

[0058] Step 5: Gradually close the circulating water inlet electric door 101 on one side of condenser A 1, and pay attention to the changes in condenser vacuum.

[0059] Step 6: When the condenser vacuum is higher than -87.5 kPa and stable, gradually close the circulating water outlet electric door on the B condenser 2 side to fully close, and pay attention to monitor the changes in the circulating water system, vacuum system and TSI parameters.

[0060] Step 7: After the unit runs stably, open the vent valves of the circulating water chamber on one side of condenser 1 of A and the circulating water chamber on one side of condenser 2 of B, open the drain gate of the circulating water connecting pipe of the water chamber on the A side of condenser, the drain gate behind the circulating water inlet gate on one side of condenser 1 of A, and the drain gate in front of the circulating water outlet gate on one side of condenser 2 of B, start the condensate pit sewage pump, and closely monitor the changes in the water level in the condensate pit.

[0061] Step 8: When the vacuum and main engine parameters are stable and within the limit, after the circulating water on the A side of the condenser is drained, the circulating water inlet electric door 101 on the A condenser 1 side and the circulating water outlet electric door 201 on the B condenser 2 side are powered off, and the manhole door on the water side of the condenser is opened for maintenance. Pay attention to the changes in the condenser vacuum when opening the manhole door.

[0062] Step 9: During the shutdown of the circulating water on one side of the condenser, monitor the current of the mechanical vacuum pump, the water level of the steam-water separator of the vacuum pump group, and the changes in the working water temperature. When the working water temperature is higher than 40°C, contact maintenance to clean the working water cooler.

[0063] Step 10: Restoration of the system after isolation.

[0064] During the maintenance process in step nine, the vacuum should be maintained at no less than -87.5kPa and the exhaust temperature should not exceed 80℃, otherwise the load should continue to be reduced and the normal operation mode should be restored after the personnel are evacuated; during the leakage detection on the condenser half side, the operating parameters of the small units of condensers A and B should be closely monitored to ensure that they are normal, the exhaust pressure of the small unit should not be higher than -70kPa, and when the exhaust temperature of the small unit is higher than 85℃, check that the water spray solenoid valve of the rear cylinder of the small unit is open.

[0065] Among them, in step five, when the vacuum drops to -90kPa, stop the operation, report the value, continue to reduce the load of the unit, and continue to operate until the vacuum stabilizes. When the load drops below 500MW, the boiler starts to use oil guns to assist combustion.

[0066] Among them, in step nine, when the exhaust temperature of the low-pressure cylinder is higher than 47°C, water is sprayed on the low-pressure cylinder in time.

[0067] Among them, in step ten, after the maintenance work is completed, close the system drain gate, inject water and release air into the circulating water chamber on the A side of condenser, slowly open the circulating water outlet electric gate on the A side of condenser B, inject water and release air into the circulating water on the A side of condenser, pay attention to the changes in the exhaust steam temperature of the low-pressure cylinder and the differential expansion of the low-pressure cylinder, after the circulating water chamber on the A side of condenser is released, slowly open the circulating water inlet electric gate on the A side of condenser A, and gradually restore the normal operation of the system.

[0068] Among them, the vacuum is maintained at no less than -87.5kPa, the exhaust temperature does not exceed 80℃, and the function is:

[0069] L=f(V,T)

[0070] When V<-87.5 and T<=80,

[0071] L=0(indicates no need to reduce load)

[0072] When V<-87.5 and T>80,

[0073] L = k1*(T-80) (where k1 is a coefficient determined according to actual conditions)

[0074] When V>=-87.5,

[0075] L = k2*(-87.5-V) (k2 is also a coefficient determined according to actual conditions)

[0076] For example, if k1=5 and the current exhaust steam temperature is 90°C, the load reduction L=5*(90-80)=50.

[0077] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for isolating a condenser, characterized in that: The following steps are involved: Step 1: Preparations before isolating the circulating water on the A side of the condenser:

1. Reduce the unit load to below 750MW.

2. Keep two vacuum pumps running. Step 2: Condenser A side circulating water isolation operation Step 3: Start one circulating water pump, stop the auxiliary pump, keep two circulating water pumps running; release the standby interlock of the third circulating water pump. Step 4: Comprehensively record the monitoring parameters of the condenser circulating water system, vacuum system, and TSI. When half of the condenser circulating water side is isolated, record the above parameters every 30 minutes. Step 5: Gradually close the circulating water inlet electric door (101) on one side of the A condenser (1), and pay attention to the change in the condenser vacuum. Step 6: When the condenser vacuum is higher than -87.5 kPa and stable, gradually close the circulating water outlet electric door on one side of condenser B (2) until it is fully closed, and pay attention to monitoring the changes in the circulating water system, vacuum system and TSI parameters. Step 7: After the unit is running stably, open the vent valves of the circulating water chamber on one side of condenser A (1) and the circulating water chamber on one side of condenser B (2), open the drain valve of the circulating water connecting pipe of the water chamber on the A side of condenser, the drain valve behind the circulating water inlet gate on one side of condenser A (1), and the drain valve before the circulating water outlet gate on one side of condenser B (2), start the condensate pit sewage pump, and closely monitor the changes in the condensate pit water level. Step 8: After the vacuum and main engine parameters are stable and within the limit, and the circulating water on the A side of the condenser is completely drained, the circulating water inlet electric door (101) on the A condenser (1) side and the circulating water outlet electric door (201) on the B condenser (2) side are powered off, and the water side manhole door on the condenser side is opened for maintenance. When opening the manhole door, pay attention to the change in the condenser vacuum. Step 9: During the shutdown of the circulating water on one side of the condenser, monitor the current of the mechanical vacuum pump, the water level of the steam-water separator of the vacuum pump group, and the changes in the working water temperature. When the working water temperature is higher than 40°C, contact maintenance to clean the working water cooler. Step 10: Restoration of the system after isolation.

2. A condenser isolation method according to claim 1, characterized in that: During the inspection and maintenance process in step nine, the vacuum is maintained not lower than -87.5kPa and the exhaust temperature does not exceed 80°C, otherwise the load continues to be reduced and the normal operation mode is restored after the personnel are evacuated; during the leakage detection process on the condenser half side, the operating parameters of the small units of the A and B condensers are closely monitored to be normal, the exhaust pressure of the small unit shall not be higher than -70kPa, and when the exhaust temperature of the small unit is higher than 85°C, check that the water spray solenoid valve of the rear cylinder of the small unit is open.

3. A condenser isolation method according to claim 1, characterized in that: In step five, when the vacuum drops to -90 kPa, the operation is stopped, the reporting value is long, the unit continues to reduce the load, and continues to operate to full shutdown after the vacuum stabilizes. When the load drops below 500 MW, the boiler is put into oil gun for combustion assistance.

4. A condenser isolation method according to claim 1, characterized in that: In the step nine, when the exhaust temperature of the low-pressure cylinder is higher than 47° C., water is sprayed into the low-pressure cylinder in time.

5. The condenser isolation method according to claim 1, characterized in that: In the step ten, after the maintenance work is completed, close the system drain valve, inject water and release air into the circulating water chamber on the A side of the condenser, slowly open the circulating water outlet electric door on the A side of the B condenser, inject water and release air into the circulating water on the A side of the condenser, pay attention to the changes in the exhaust steam temperature of the low-pressure cylinder and the differential expansion of the low-pressure cylinder, after the circulating water chamber on the A side of the condenser is released, slowly open the circulating water inlet electric door on the A side of the A condenser, and gradually restore the normal operation of the system.

6. A condenser isolation method according to claim 1, characterized in that: Keep the vacuum not lower than -87.5kPa, and the exhaust temperature not exceed 80℃. The function is: L=f(V,T) When V<-87.5 and T<=80, L=0(indicates no need to reduce load) When V<-87.5 and T>80, L = k1*(T-80) (where k1 is a coefficient determined according to actual conditions) When V>=-87.5, L = k2*(-87.5-V) (k2 is also a coefficient determined according to actual conditions) For example, if k1=5 and the current exhaust steam temperature is 90°C, then the load reduction L=5*(90-80)=50.

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