Pressure and flow issues of leakage gas in series dry gas seals
Thread Content
For the primary leakage gas of the series-connected dry gas seal, there are alarms for high leakage gas pressure and low flow rate; these two constitute a two-out-of-two interlock system. What situations could cause this phenomenon to occur, and what impacts might it have?
The 2-out-of-2 interlock is a shutdown mechanism triggered when both pressure and flow are at high levels
Using two out of two as the interlock mechanism is the least reliable approach; I recommend that you change it. If either instrument fails, it means that this interlock protection is no longer effective.
Isn’t it safer to choose either high flow rate or high pressure? In the event of a false alarm, there will be no interlocked shutdown!
Or it may be that the gas leakage and ignition flow are not proper; there is high pressure but low flow, and this does not trigger the shutdown interlock. If both parameters are at high levels, it is determined that there is a seal leakage, which makes shutdown more necessary
If one gauge is damaged and its reading does not change, another gauge, no matter how high its reading is, will not trigger the interlock. From a production perspective, two-out-of-two is advantageous, but the safety factor **decreases**.
Setting up interlocking relationships is a specialized task; there is a certain relationship between the pressure and flow rate of the leaking gas, but this relationship is not always perfect. For example, if accumulation of fluid in the discharge line due to leakage causes high backpressure, this will result in high pressure and low flow rate； Personally, I recommend a two-out-of-two interlock using two pressure transmitters; the high and high flow alarms are set as references only and do not participate in the interlock.
Pressure and flow present simultaneously; 2 out of 2, more convincing