Usage of molecular sieve adsorbents
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Dear seniors, after the air separation unit stopped operating, the molecular sieves were not protected with nitrogen (due to a lack of gas supply) for as long as 5 months. Can the molecular sieve adsorbents still be used after activation? It’s uop13x’s.
It works; molecular sieves aren’t that fussy.
It can be used, as long as no rainwater or anything else gets in~~ Hehe~~
However, in the case of a long period of shutdown, it is still recommended to run a cycle with the molecular sieve after restarting, to prevent impurities from penetrating~~
Dear seniors, does the air duct (from the air compressor outlet to the cold box inlet) still need to be purged? I’m worried that rust debris might end up in the heat exchanger and the expansion device! Because it’s very difficult to purge with molecular sieves!
Starting the air compressor for purging is not difficult at all~~ As long as the dew point and carbon dioxide levels after the molecular sieve are within acceptable limits, the process can proceed~~ If there are concerns regarding rust or debris, it’s possible to avoid introducing material into the tower by using the purge valve before air enters the tower~~ You can make modifications by introducing nitrogen or air with an acceptable dew point into the molecular sieve and the tower to maintain pressure (a slight positive pressure is sufficient), which helps prevent rusting and reduces startup time~~
If the original poster has any questions regarding molecular sieves, we can discuss them:)
Special regeneration. Let’s see what the cold blow peak is like.
The adsorber does not have an open end, so little moisture from the outside can enter it. If possible, it is advisable to carry out high-temperature activation before reuse in order to improve the adsorption capacity of the molecular sieve; if such conditions are not available, performing the regeneration process several times will suffice.
:Thank you first for the handshake. Because all the air separation units are shut down and there is no gas supply (liquid nitrogen vaporization was not purchased to save costs), nitrogen cannot be filled in. I’m worried that over time, the pipes running from the air-cooling tower to the molecular sieve might rust due to the presence of moisture in those pipes.
Is the moisture level here as high as it is during normal operation? Hehe~~ I was really scared, so while the machine was shut down, I made a cut in the pipeline and welded in a purge valve~~ I made sure to blow it out thoroughly before turning the machine back on~~