Seeking advice on emergency shutdown issues of new hydrogen compressors
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The PSA supplies new hydrogen at a pressure of 4.0~4.5 MPA; it reaches the liquid separation tank at the new hydrogen inlet (with a safety valve set at 4.6 MPA), and then goes to the new hydrogen compressor (a two-stage, reciprocating compressor equipped with a load regulator). Question: 1. During an emergency shutdown, what procedures should be followed to prevent the safety valve of the inlet separation tank from activating? 2. What should be done if the PSA shuts down urgently?
1. In the event of an emergency stop, quickly close Loop 1-1, Loop 2-2, and Loop 2-1; if the closing is delayed, the safety valve of the separation tank will definitely activate. 2. If PSA stops, the new hydrogen generator reduces its load and stops supplying hydrogen
There are things that are unavoidable; try to avoid them as much as possible. An emergency stop usually results in a chain reaction of stops
The PSA has been stopped; the system can be set to a longer cycle. The new hydrogen generator should first operate at zero load, and the supply of new hydrogen to the system should be shut off. After the PSA returns to normal, increase the pressure and send it back; if this doesn’t work after a while, stop operation as usual
Hello, the key issue is that the safety valve of the new hydrogen inlet separator tank trips at 4.6 MPA, while the new hydrogen compressor normally compresses the gas to 17–18 MPA after two stages; it is equipped with four buffer tanks. If there is no load, the pressure equalization caused by these buffer tanks alone can trigger the safety valve of the new hydrogen inlet separator tank…
In emergency situations, there are many places where pressure can build up from high to low in the system. Doesn’t the buffer tank at the fresh hydrogen inlet have pressure control? You can only guarantee that it won’t trip during normal shutdowns. Lowering the pressure control setpoint below 4.0 during shutdown can prevent this
Mm-hmm, it seems that emergency situations are indeed difficult to handle properly
A reciprocating compressor can’t hold pressure, right? It’s not possible to simply shut off the return line, is it?
How can pressure build up if the outlet valve doesn’t close? After an emergency shutdown, it stops producing power – so how can pressure build up? Turning it off once or twice is to prevent the secondary stage from interfering with the primary stage, as well as the primary outlet from interfering with the primary inlet, which could cause the pressure relief valve in the inlet liquid separation tank to activate
Thank you, I see. It seems that our instructions regarding such emergency handling are still too vague and need to be improved
May I ask, what should be done with the PSA system when the new hydrogen compressor suddenly shuts down? There is about 12,000 cubic meters of product hydrogen – is it all to be vented through the flare?