【Q&A Question 106】2016.08.04
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【Q&A Question 106】August 4, 2016: Why is it necessary to start the steam seal extractor first when starting a back-pressure turbine? The answer key will be available after responding; scoring is based on answering the key points. Prevent backpressure steam from entering other systems.
The outlet pressure is high; otherwise, pressure builds up and leaks from the shaft end, causing the loss of lubricating oil as well.
Due to the high exhaust pressure, it is necessary to prevent a large amount of steam from leaking out of the machine at startup; otherwise, some of this steam may mix with the lubricating oil, causing the oil to contain water and leading to damage to the seals. Therefore, it is necessary to first start the steam seal extractor and the steam seal cooler to create a certain level of vacuum, thereby drawing out the exhaust steam and cooling it into condensed water.
Prevent steam from entering the lubricating oil system and prevent steam from leaking from the shaft ends
To prevent steam from leaking out through the shaft seal or entering the compressor’s lubricating oil and thus damaging the compressor, the steam from the shaft seal is first vented to be condensed into water and then removed
Due to the high exhaust pressure, if the steam seal extractor and steam seal cooler are not activated first before starting up, a large amount of steam will leak out of the machine through the shaft ends. Moreover, some of this steam will mix into the lubricating oil, causing it to become contaminated with water. Therefore, it is necessary to turn on the steam seal extractor and steam seal cooler first to create a certain level of vacuum, which will draw the exhaust steam out and cool it into condensate water.
The steam seal extractor and steam seal cooler should be turned on to prevent large amounts of steam from leaking out of the machine at the shaft end. It is also necessary to prevent some of the steam from mixing into the lubricating oil, which could cause the oil to contain water; therefore, it is essential to first activate the steam seal extractor and steam seal cooler to create a certain level of vacuum, thereby drawing the exhaust steam out and cooling it into condensed water.
1. Extract non-condensable gases from the system； 2. Establish negative pressure ； 3. Check the system’s sealing performance
Due to the high exhaust pressure, it is necessary to prevent a large amount of steam from leaking out of the machine at startup; otherwise, some of this steam may mix with the lubricating oil, causing the oil to contain water and leading to damage to the seals. Therefore, it is necessary to first start the steam seal extractor and the steam seal cooler to create a certain level of vacuum, thereby drawing out the exhaust steam and cooling it into condensed water.