The molecular sieve purifier in air separation equipment achieves sieving and separation of molecules of different sizes, shapes, and polarities through its unique pore structure and surface properties. It is mainly used to remove impurities such as moisture and carbon dioxide from the air. The adsorption temperature is an important reference indicator when determining whether the molecular sieve purifier is working properly. For the molecular sieve purifiers of medium and large full low pressure air separation equipment, the designed adsorption temperature is usually selected in the lower temperature range of 8-15 ℃.
Monitoring of adsorption temperature curve: 1. Horizontal straight line. Under normal conditions of the air pre cooling system, the temperature of the air entering the purifier is relatively stable, so the adsorption temperature curve should appear as an approximately horizontal straight line for most of the time. 2. The temperature difference changes, and the air outlet temperature will be slightly higher than the inlet temperature due to the influence of adsorption heat release. When the air inlet temperature is 10 ℃, its temperature rise is about 4 ℃. However, if the outlet temperature of the purifier suddenly rises during use, it may indicate that air has brought water from the air cooling tower into the adsorber, and emergency treatment should be taken at this time. 3. Switching temperature difference: At the beginning of the adsorber switching, due to the increase in adsorption capacity of the molecular sieve during the boosting process and the adsorption heat generated by the adsorption of some molecules, there will be a large temperature difference between the inlet and outlet, even up to 20 ℃. This is a normal phenomenon and does not indicate abnormal operation of the adsorber.
The abnormal increase in outlet temperature may be due to air carrying water from the air cooling tower into the adsorber. At this point, the relevant components of the air cooling tower and adsorber should be inspected to ensure that there are no leaks or improper operations. If there are abnormal fluctuations or peaks in the adsorption temperature curve, it may be caused by insufficient regeneration heat source (steam or electricity), insufficient gas volume, changes in adsorber load, or increased adsorber resistance. At this point, a detailed inspection should be conducted on the heating system, inlet and outlet valves, and bed status of the adsorber.
