【Q&A Question 092】2017.04.02
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【Q&A Question 092】April 02, 2017: What should be done after a safety valve activates? The reference answers will be visible after responding; points are awarded by identifying the key points. (Unless otherwise specified, all questions and answers are based on hydrogenation units.) ) Answer: Once the safety valve activates, the operator on duty should immediately reduce the pressure. If the pressure does not drop, they should promptly contact the operator outside to open the pressure control valve or the vent line in order to bring the pressure back to normal levels. At the same time, the shut-off valves upstream and downstream of the safety valve should be closed, and maintenance personnel should be contacted to set a fixed pressure for the safety valve; after that, it can be reinstalled. 2017 Q&A Summary Thread (updates have begun) http://bbs.hcbbs.com/thread-1657793-1-1.html 2017 Daily Question Summary Thread (updates have begun) http://bbs.hcbbs.com/thread-1657794-1-1.html 2016 Q&A Summary Thread (updates completed) http://bbs.hcbbs.com/thread-1597792-1-1.html Third Round of Haichuan Outstanding Management Members Selection Contest http://bbs.hcbbs.com/thread-1655902-1-1.html (Source: Haichuan Chemicals Forum)
Check whether it returns to its seat properly after activation, that is, whether the safety valve still maintains a good seal as before. If there are no issues such as leaks, no special action is required. If there is a leak, the safety valve must be repaired and recalibrated by the designated service department! Also note that if your safety valve operates frequently, it may indicate that its set pressure is incorrect; it needs to be sent to a calibration facility for re-calibration!
Once the pressure returns to normal, switch to the backup safety valve; after it activates, remove the safety valve for inspection.
If the pressure becomes excessively high, relieve the pressure immediately and remove the safety valve; if the safety valve fails, remove it right away so that the production system can return to normal operation
After the safety valve activates, the pressure control valve bypass line or vent line should be opened immediately to reduce the pressure back to the normal range. Then, it is necessary to check whether the safety valve can reset automatically; if it cannot, the safety valve manual valve should be closed, the valve taken apart for repair, recalibrated, and then reinstalled
Check the reason for the safety valve to activate and take corresponding action to determine whether it is a problem with the safety valve itself or actual overpressure. After taking off, check whether the safety valve returns to its original position
If the pressure of the equipment becomes excessively high, causing the safety valve to activate, the pressure-controlled bypass line or flare line should be used immediately to reduce the pressure back to normal levels. Check whether the safety valve has returned to its normal position; if it cannot do so, close the safety valve’s manual valve and remove it for repair.
Check whether it returns to its seat properly after activation, that is, whether the safety valve still maintains a good seal as before. If there are no issues such as leaks, no special action is required. If there is a leak, the safety valve must be repaired and recalibrated by the designated service department! Also note that if your safety valve operates frequently, it may indicate that its set pressure is incorrect; it needs to be sent to a calibration facility for re-calibration!
Check whether it returns to its seat properly after launching; if there are no issues such as leaks, no special action is required. If there is a leak, it must be repaired and calibrated again!
What I have encountered is that the safety valve of the steam generator in our system opens when the pressure reaches 1.2 Mpa, as the set pressure is relatively low; once this pressure is approached, the safety valve activates, and the pressure drops quickly afterward, causing the valve to return to its normal position. In winter, a small amount of steam escapes from the vent silencer, but this does not happen at other times