Molecular sieves commonly used in industrial production in China are 3a, 4a, 5A, 13X so on. The service life is related to environmental humidity, test pressure, sealing of packaging. Under normal circumstances, it can be used for 2-3 years. If well managed, it can be used for more than 5 years without major production accidents.
For manufacturers who use molecular sieve products, everyone is concerned about one question: "how to extend the service life of molecular sieves?" In fact, the two main factors affecting the life of molecular sieves are two correct factors: correct use regular maintenance in the process of use.
Molecular sieves are used correctly. In the process of molecular sieve adsorption, the design value of adsorption equipment should be strictly followed, the key indicators such as feed flow rate, temperature, pressure, switching time set by the system should be strictly observed. These are very important. A properly designed properly used molecular sieve adsorption unit should be used between 24'000 40'000 hours, taking about 3 to 5 years. Molecular sieves are only purchased unless it is explicitly indicated that it has been activated sealed. Otherwise, high temperature baking activation is still needed, usually 500 degrees is enough. The activation is carried out in a muffle furnace. Air nitrogen in the muffle furnace passes through the cylinder, then it is naturally cooled to about 100 ℃ under ventilation conditions. After being taken out, it is transferred to a dryer for airtight storage.
Daily maintenance of using medium molecular sieve: appropriate molecular sieve, reduce moisture in the air, prevent lubricating oil pollution, heat correctly, clean powder in time. In addition, in the process of molecular sieve, it is suitable to use room temperature air to the molecular sieve bed for the dry gas of the product treated by molecular sieve the low dew point gas of the process in other places, especially in the bottle blowing stage, which is usually counterproductive. In this process, heating should be carried out slowly in stages, directly to 200-300 degrees. When the molecular sieve bed is directly blown back, the gas must be kept at about 150 ℃. Heating time is also the focus of attention.
So how to judge whether the molecular sieve in use needs to be replaced? Generally, it is necessary to replace it according to the instructions when it is due, but if there is water, it needs to be replaced at any time according to the situation, because even if the method is used after immersion in water, the molecular sieve will break under the action of air flow hinder heat exchange. There is something wrong with the equipment. In addition, it depends on whether the water content carbon dioxide content of the purified gas are within the target range. If it exceeds the target, it needs to be replaced.