Is there a sequence in which the various products from large air separation units are produced? What order? Why is it like this?
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Is there a sequence in which the various products from large air separation units are produced? What order? Why is it like this? At our plant’s 60,000 capacity air separation unit, sometimes nitrogen at 0.5 Mpa is released first, and sometimes oxygen at atmospheric pressure is released first. Is this related to the operating procedures? What should be the order under normal circumstances? Explain the reason. Could someone please advise me on how to change the order in which the products are displayed?
Once adjusted properly, oxygen and nitrogen will be released in roughly equal amounts; argon is of course something to consider only after oxygen and nitrogen have stabilized. The purity of the product depends mainly on the throttle valve and flow regulation
The general order of adjustment should be oxygen, nitrogen, then argon; of course, this depends on the process and operating procedures (i.e., achieving the design values). What the poster mentioned – nitrogen at 0.5 Mpa coming out first – might be due to your process in which low-pressure nitrogen is drawn directly from the lower column.
Liquid air separation: Medium-pressure nitrogen with high purity is produced quickly. If nitrogen under pressure is directly drawn as the product, of course nitrogen will be released quickly. However, if the backflow ratio is normal, oxygen may be released first. The key is not to discharge large amounts of waste liquid, and adjustments should be made based on what was mentioned earlier.
It should be related to both the processes and operations. It is possible that the gas that comes out first is of substandard purity.
Gas that does not meet the purity standards definitely cannot be supplied for external use. Learn* it! Thank you to all the experts for their guidance.
When the liquid level in the evaporator rises to a certain level, such as 20% or 30%, it indicates that the evaporator is working properly; at this point, the valve can be closed slowly. By controlling the opening degree of the liquid-air throttle valve, the liquid level in the lower column can be kept stable. As you gradually close the liquid nitrogen throttle valve, both the reflux ratios in the upper and lower columns change, and the resistance in the columns also increases. Whether you are producing medium-pressure nitrogen or low-pressure nitrogen, the purity of oxygen and nitrogen will improve quite quickly. I have tried this method, and it allows for a fast start-up process, thereby effectively reducing the time required to get the system operational.
It depends on the cooling temperature at which the gas turns into a liquid; nitrogen seems to require a temperature of -188 degrees, while oxygen reaches that state at a lower temperature
In fact, the order of oxygen and nitrogen can be adjusted; it depends mainly on the user’s requirements. You can decide which one should be processed first, depending on what you need most. After that come argon, krypton, xenon, neon, and helium. Generally, if there are no special requirements, nitrogen is processed first!