How can the switch from the imported expander to a domestically produced expander for the internal pressure air separation unit be operated with minimal fluctuations? ? ? ? ?
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Domestic expanders require startup under reduced pressure; what are the procedures for switching them during normal operation, and what precautions should be taken? 、、
Since it is an internal-pressure air separation system, the amount of gas entering the expander is limited by the pumping action in the booster; care must be taken to avoid surge during the switching process. If you want to minimize the impact on the system, you can first reduce the pressure of the expansion machine in operation, ensuring a minimum amount of air intake. By using exhaust gas extraction from the booster pump instead of recirculation, stability can be achieved, though some gas will be wasted in the process. At this point, you can start another expander to gradually increase the degree of expansion; then the two expanders can share the air flow, and by working in conjunction with the booster, the switching can be completed with less impact
First, reduce the load on the main expansion machine, then start the backup expansion machine according to the operation instructions; thereafter, one expansion machine should have its load increased while the other continues to have its load reduced until it stops operating! During operation, attention should be paid to ensuring the proper functioning of the booster pump; do not allow rapid operation to affect the stable functioning of the unit!
It follows the same operation principle as during hot start, when both expanders are used simultaneously for starting and stopping
When switching our expanders, we usually keep the reflux from the booster pump active; the vacuum valve is only opened in emergency situations.
May I ask if you are using an expansion machine powered by aviation oxygen? We also use domestic expanders; the manufacturer requires this as well. However, we have started the machine again after allowing the pressure to drop a little bit, and this doesn’t have much impact on either the expander or the system. Perhaps we’re going against the operating instructions provided by the manufacturer, but practice has shown that this approach works. Of course, we don’t know if it works for everything. Hope to hear from my friends' suggestions!
We are the expanders manufactured by Hangyang. What is stated in the instructions makes sense; although a slight drop in pressure does not affect the equipment, I still think it’s necessary to follow the instructions. If the equipment is damaged as a result, we wouldn’t be able to take responsibility for that. . . The pressure as we enter the expander is 3.8 MPA.
Hehe! Yes, safety comes first. It’s right to follow the operating procedures. This might be a flaw in their expander design! It still has some impact on the system if the pressure is reduced to less than 10 kilograms before starting the other unit; the load might be lowered within a short period of time.
It is advisable to pre-cool the other expander before starting it, prior to switching over to that expander