One Question per Day 20181226
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How to check for leaks in one half of a condenser? (1) Contact the shift supervisor to reduce the unit load to about 70% of the rated load (when the condensate hardness is too high, the load must be reduced further, and the second set of extraction systems should be activated). (2) Appropriately increase the steam supply pressure for the shaft seal. (3) Slightly increase the inlet valve of the circulating water for the condenser on the side that will not be inspected for leaks. (4) Close the air valve from the condenser on the leak-check side to the extractor. (5) Close the circulating water inlet valve and the connecting valve on the side used for leak detection, adjust the circulating water air valve; after these valves are closed, the switch handle must be moved to the manual position. (6) After confirming that the unit is operating normally, open the drain valve of the condenser on the side that is not in use. (7) The condenser vacuum must not be lower than 85 kPa, and the exhaust steam temperature should not exceed 70°C. (8) Open the manway of the condenser on one side to shut it down and proceed with leak detection. (9) After checking for any omissions, the team leader shall verify that there is no one present and no tools left behind, and then close the condenser manhole and drain valve. (10) Open or close the circulating water inlet valve on one side of the condenser, adjust the circulating water air valve and the circulating water connection valve, and adjust the circulating water inlet valve on the other side accordingly. (11) Deactivate the condenser on one side until the air valve of the extraction pump is opened. (12) Check for leaks in the other side of the condenser using the same method. (13) During the leak detection process, the vacuum level of the condenser should be no less than 87 KPa, and the trend should remain stable; otherwise, the cleaning of one half of the condenser should be stopped to restore the operation of the condenser on the side that is being cleaned as soon as possible.
Turn off the exhaust and cooling water on both sides respectively, and observe the changes in vacuum level
1) If the leakage in the condenser cooling water pipes is minor during operation, and the quality of the condensate is generally acceptable, there is no need to shut down the unit. The leak can be sealed by adding sawdust to the cooling water, thereby allowing the unit to continue operating. Once an opportunity arises to shut down the unit, the source of the leakage can be identified, and the leaking pipe can be blocked using special copper rods； 2) For split-unit turbines, the unit’s load can be reduced by half; water supply to one half of the turbine is stopped in order to identify the side where leakage occurs. Before stopping the water supply, the air valve leading to the exhaust pump must be closed to prevent uncondensed steam from entering the exhaust pump and affecting its operation. Once the side with the leakage is identified, maintenance can be carried out on that half of the turbine while it is still in operation – by opening the end cover or access door of the condenser’s water chamber. Methods for detecting leaks include the candle test and visual inspection; this is because water flow is generally minimal, if any, on the sides of the pipes where there is leakage, while there is more water flow on the sides of the pipes that are not leaking ； 3) Leak detection during shutdown: Open the end caps on both sides of the condenser, and use an air compressor to blow out any remaining water from the cooling water pipes. Ensure that there are no signs of water at either end of the pipes. Support the bottom of the condenser with springs, then open the access door on the steam side and pour softened water in until it covers the top copper tubes. Check both sides of the pipes; if water flows out, there is a leak. Block the leak using a copper rod at each end. If there are signs of water on the pipe walls, it indicates that the joint is leaking, and the pipe can be re-expanded using a pipe expander until no more water is detected on either side of the pipe, indicating that the leak has been successfully fixed.
1) If the leakage in the condenser cooling water pipes is minor during operation, and the quality of the condensate is generally acceptable, there is no need to shut down the unit. The leak can be sealed by adding sawdust to the cooling water, thereby allowing the unit to continue operating. Once an opportunity arises to shut down the unit, the source of the leakage can be identified, and the leaking pipe can be blocked using special copper rods； 2) For split-unit turbines, the unit’s load can be reduced by half; water supply to one half of the turbine is stopped in order to identify the side where leakage occurs. Before stopping the water supply, the air valve leading to the exhaust pump must be closed to prevent uncondensed steam from entering the exhaust pump and affecting its operation. Once the side with the leakage is identified, maintenance can be carried out on that half of the turbine while it is still in operation – by opening the end cover or access door of the condenser’s water chamber. Methods for detecting leaks include the candle test and visual inspection; this is because water flow is generally minimal, if any, on the sides of the pipes where there is leakage, while there is more water flow on the sides of the pipes that are not leaking ； 3) Leak detection during shutdown: Open the end caps on both sides of the condenser, and use an air compressor to blow out any remaining water from the cooling water pipes. Ensure that there are no signs of water at either end of the pipes. Support the bottom of the condenser with springs, then open the access door on the steam side and pour softened water in until it covers the top copper tubes. Check both sides of the pipes; if water flows out, there is a leak. Block the leak using a copper rod at each end. If there are signs of water on the pipe walls, it indicates that the joint is leaking, and the pipe can be re-expanded using a pipe expander until no more water is detected on either side of the pipe, indicating that the leak has been successfully fixed.
1) Contact the shift supervisor to reduce the unit load to around 70% of the rated load (when the condensate hardness is too high, the load must be reduced further, and the second set of extraction systems should be activated). (2) Appropriately increase the steam supply pressure for the shaft seal. (3) Slightly increase the inlet valve of the circulating water for the condenser on the side that will not be inspected for leaks. (4) Close the air valve from the condenser on the leak-check side to the extractor. (5) Close the circulating water inlet valve and the connecting valve on the side used for leak detection, adjust the circulating water air valve; after these valves are closed, the switch handle must be moved to the manual position. (6) After confirming that the unit is operating normally, open the drain valve of the condenser on the side that is not in use. (7) The condenser vacuum must not be lower than 85 kPa, and the exhaust steam temperature should not exceed 70°C. (8) Open the manway of the condenser on one side to shut it down and proceed with leak detection. (9) After checking for any omissions, the team leader shall verify that there is no one present and no tools left behind, and then close the condenser manhole and drain valve. (10) Open or close the circulating water inlet valve on one side of the condenser, adjust the circulating water air valve and the circulating water connection valve, and adjust the circulating water inlet valve on the other side accordingly. (11) Deactivate the condenser on one side until the air valve of the extraction pump is opened. (12) Check for leaks in the other side of the condenser using the same method. (13) During the leak detection process, the vacuum level of the condenser should be no less than 87 KPa, and the trend should remain stable; otherwise, the cleaning of one half of the condenser should be stopped to restore the operation of the condenser on the side that is being cleaned as soon as possible.
(1) Contact the shift supervisor to reduce the unit load to about 70% of the rated load (when the condensate hardness is too high, the load must be reduced further, and the second set of extraction systems should be activated). (2) Slightly increase the steam supply pressure to the shaft seal. (3) Slightly increase the inlet valve of the circulating water for the condenser on the side that will not be inspected for leaks. (4) Close the air valve from the condenser on the leak-check side to the extractor. (5) Close the circulating water inlet valve and the connecting valve on the side used for leak detection, adjust the circulating water air valve; after these valves are closed, the switch handle must be moved to the manual position. (6) After confirming that the unit is operating normally, open the drain valve of the condenser on the side that is not in use. (7) The condenser vacuum must not be lower than 85 kPa, and the exhaust steam temperature should not exceed 70°C. (8) Open the manway of the condenser on the side that is not in use to enter and check for leaks. (9) After checking for any remaining items, the team leader shall verify that there is no one present and no tools left, and then close the condenser manhole and drain valves. (10) Open the inlet valve for circulating water to the condenser on the side that is not in use, adjust the air valve and the connection valve for circulating water, and set the inlet valve for circulating water on the other side to the correct position. (11) Shut down the condenser on one side until the air valve of the extraction pump is opened. (12) Check for leaks in the other side of the condenser using the same method. (13) During the leak detection process, the vacuum level of the condenser should be no less than 87 KPa, and the trend should remain stable; otherwise, the cleaning of one half of the condenser should be stopped, and operation of the condenser on the side being cleaned should be resumed as soon as possible.
? (1) Contact the shift supervisor to reduce the unit load to about 70% of the rated load (when the condensate hardness is too high, the load must be reduced further, and the second set of extraction systems should be activated). (2) Slightly increase the steam supply pressure to the shaft seal. .
1) If the leakage in the condenser cooling water pipes is minor during operation, and the quality of the condensate is generally acceptable, there is no need to shut down the unit. The leak can be sealed by adding sawdust to the cooling water, thereby allowing the unit to continue operating. Once an opportunity arises to shut down the unit, the source of the leakage can be identified, and the leaking pipe can be blocked using special copper rods； 2) For split-unit turbines, the unit’s load can be reduced by half; water supply to one half of the turbine is stopped in order to identify the side where leakage occurs. Before stopping the water supply, the air valve leading to the exhaust pump must be closed to prevent uncondensed steam from entering the exhaust pump and affecting its operation. Once the side with the leakage is identified, maintenance can be carried out on that half of the turbine while it is still in operation – by opening the end cover or access door of the condenser’s water chamber. Methods for detecting leaks include the candle test and visual inspection; this is because water flow is generally minimal, if any, on the sides of the pipes where there is leakage, while there is more water flow on the sides of the pipes that are not leaking ； 3) Leak detection during shutdown: Open the end caps on both sides of the condenser, and use an air compressor to blow out any remaining water from the cooling water pipes. Ensure that there are no signs of water at either end of the pipes. Support the bottom of the condenser with springs, then open the access door on the steam side and pour softened water in until it covers the top copper tubes. Check both sides of the pipes; if water flows out, there is a leak. Block the leak using a copper rod at each end. If there are signs of water on the pipe walls, it indicates that the joint is leaking, and the pipe can be re-expanded using a pipe expander until no more water is detected on either side of the pipe, indicating that the leak has been successfully fixed.
(1) Contact the shift supervisor to reduce the unit load to about 70% of the rated load (when the condensate hardness is too high, the load must be reduced further, and the second set of extraction systems should be activated). (2) Slightly increase the steam supply pressure to the shaft seal. (3) Slightly increase the inlet valve of the circulating water for the condenser on the side that will not be inspected for leaks. (4) Close the air valve from the condenser on the leak-check side to the extractor. (5) Close the circulating water inlet valve and the connecting valve on the side used for leak detection, adjust the circulating water air valve; after these valves are closed, the switch handle must be moved to the manual position. (6) After confirming that the unit is operating normally, open the drain valve of the condenser on the side that is not in use. (7) The condenser vacuum must not be lower than 85 kPa, and the exhaust steam temperature should not exceed 70°C. (8) Open the manway of the condenser on the side that is not in use to enter and check for leaks. (9) After checking for any remaining items, the team leader shall verify that there is no one present and no tools left, and then close the condenser manhole and drain valves. (10) Open the inlet valve for circulating water to the condenser on the side that is not in use, adjust the air valve and the connection valve for circulating water, and set the inlet valve for circulating water on the other side to the correct position. (11) Shut down the condenser on one side until the air valve of the extraction pump is opened. (12) Check for leaks in the other side of the condenser using the same method. (13) During the leak detection process, the vacuum level of the condenser should be no less than 87 KPa, and the trend should remain stable; otherwise, the cleaning of one half of the condenser should be stopped, and operation of the condenser on the side being cleaned should be resumed as soon as possible.