Problems with molecular sieves

It shouldn’t be that it starts to drop only during pressure relief; does it begin to drop during the equalization phase before pressure relief?

During voltage equalization, the pressure at the compressor outlet also decreases; by the time parallel operation is achieved, the pressure has returned to normal

It is caused by internal leakage in the switch valve; check whether the installation direction of the switch valve is correct. It is the set of switch valves responsible for pressure relief, and there is a higher likelihood of internal leakage in those air valves. (For reference)

Under normal conditions: Pressure drop occurs only when the molecular sieve is pressurized or connected in parallel. This is because increased gas flow is required when pressurization takes place, and the resistance of the molecular sieve decreases when it is connected in parallel. Please, the original poster, confirm here what the time is. If it is as the original poster said, then it is possible that there is a leak in the pressure charging valve or the inlet valve. Can we compare whether this is the same for both molecular sieves when they release pressure?

Yes, this situation exists in both types of molecular sieves. However, case 1# is more severe, with the outlet pressures of the booster and air compressor dropping by 0.2 MPa

My opinion on this issue is as follows: When the molecular sieve is first switched over, the temperature of the adsorbent after cooling is higher than the temperature of the air entering the molecular sieve; coupled with the exothermic reaction that occurs during adsorption, this results in a relatively high temperature of the gas exiting the adsorbent right after it has been switched over. 1. The air compressor operates under pressure control, which causes the system’s air intake volume to remain high for a short period of time (10 minutes?) ) is declining. 2. The temperature at the inlet of the booster is higher; consequently, the air flow rate decreases naturally at the same guide vane opening. It’s just my personal opinion, for reference only, hehe. Take another close look to see if this phenomenon occurs when you make the switch

I analyze that there are several possible explanations: 1) There may be leaks at the air outlet of purifier 1# or at the inlet for regenerated gas of purifier 2# (without reverse installation or damaged sealing surfaces). 2) The pressure equalization valve in the system might be located behind the purifiers, causing severe leakage in one of the circuits. 3) I disagree with the idea that the increased temperature on the 7th floor leads to a reduction in the system’s gas flow; changes in the temperature of process air do not have a significant impact on pressure, and moreover, as the flow rate decreases, the resistance throughout the system also decreases. It is precisely because of the excessive losses due to local leaks that the back pressure of the booster compressor and the air compressor decreases, and the reduced amount of high-pressure air results in a decrease in the cooling capacity of the main heat exchanger, thereby lowering the temperature before expansion.

Leakage inside the switch valve of the molecular sieve, or damage to the valve gasket causing leakage

:victory: Haha, learn*learn*,

During synchronization, the outlet pressure of the air compressor decreases; whereas during pressure relief, the outlet pressure of the air compressor increases. This is because during pressure relief, the air inlet and outlet valves, as well as the pressure equalizing valve and the gas generation inlet and outlet valves, are all closed, with only the pressure relief valve open. When there is approximately 3,000 cubic meters of air volume, the pressure at the air compressor outlet is adjusted by using the vent valve to bring it to the required value. From the start of synchronization until pressure relief, the outlet pressure of the booster compressor and the intermediate extraction pressure decrease significantly. At this point, the pressure of the booster compressor should be adjusted appropriately. Since the pressure and flow rate of the forward-flowing air decrease while the load associated with the backflow of cold air remains unchanged, the inlet temperature of the expansion machine drops, as does the temperature downstream of it. In severe cases, the expansion machine may operate with liquid present in it. However, the effects of such changes caused by the molecular sieve pressure equalizing mechanism on the expansion machine are not very significant; such fluctuations are normal. If the person in question feels that it’s a problem, they can adjust the outlet temperature of the expansion machine using its nozzle and return valve, or they can reduce the cooling load slightly. But I suggest keeping a close watch on the situation. If it doesn’t affect the process parameters, it’s best not to reduce the load. This is just my personal opinion.

If the outlet pressure of the air compressor drops significantly during pressure relief, it is likely that there is internal leakage in the valve

It is recommended that the original poster provide the temperature parameters of the purifier for reference; it seems a bit like theoretical discussion without sufficient comprehensive data! Is your air compressor control program manual or automatic? How is pressure compensation carried out?