Some discussions on molecular sieves

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Molecular sieves, which are commonly used as air purification devices in air separation equipment today, are widely applied. I have a few questions and hope that those with more experience can offer some guidance: 1. When one molecular sieve unit is in operation while another is being regenerated, as the molecular sieve being regenerated heats up, its temperature starts to drop continuously (I’ve seen it drop to several degrees below zero); it takes some time before its temperature begins to rise again； When it blows cold air, the temperature of the regenerated gas exiting the molecular sieve actually rises continuously at first (in our case, it increased from 120°C to 150°C after the heating process ended), and only after some time does it start to drop... We hope experts can provide a detailed explanation for this phenomenon ； 2. When the molecular sieve is heated or cooled by forced air, it is necessary to adjust the opening degree of the valve that sends the contaminated nitrogen gas out of the distillation tower to the purification system; this also requires adjusting the opening degree of the nitrogen vent valve in order to maintain a certain temperature difference in the hot section of the plate heat exchanger. The reasons and principles behind these operations, as well as the methods for carrying them out, are not entirely clear – I would appreciate guidance from those with more experience ； 3. When stopping temporarily or for an extended period before resuming driving, since the molecular sieve purification system operates automatically according to a schedule, the system will come to a halt at a certain step in that schedule; how should one proceed? ? It would be great if an expert could provide detailed instructions on the procedures and methods for shutting down and restarting the molecular sieve… Thank you