Nitrogen flow rate for liquid nitrogen washing
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After the start-up of nitrogen washing in our company using liquid nitrogen was completed normally, the flow rate of the washing nitrogen suddenly dropped to half; even after opening the valves fully, the flow rate did not reach the normal level. The analysis shows that both the medium-pressure nitrogen dew point and COO are within acceptable limits. Have any manufacturers found problems with this angle valve for washing nitrogen?
Should a sample be taken before driving? If sampling is not done before driving, is there a possibility of water or CO2 entering?
Check the pressure before and after the angle valve to see if it has solidified
Check the pressure before and after the angle valve to see if it has solidified.
The pressure difference before and after the angle valve increases. Treatment: Parking and backflushing works, but it does not restore normal conditions. It indicates that something is blocking the flow path of the angle valve; the backwashing process did not ensure that all substances were removed. After driving again, there were signs of congestion in the channel, and the liquid nitrogen flow decreased. The pressure differences in raw gas heat exchangers 1 and 2 have not increased, which indicates that the freezing point of the crystalline substance is low; it’s not possible to determine what substance it is. (I initially suspect it to be methanol; before this phenomenon occurred, the system experienced an emergency shutdown, the nitrogen pipeline lost pressure, and the valve used to supply pressure to the methanol washing tower was opened for a while.)