【Front-end Purification System-1】What are the advantages and disadvantages of a double-bed system?
Thread Content
Currently, molecular sieves are used in a dual-bed configuration; in the direction of the gas flow, they consist of an alumina bed layer followed by a molecular sieve bed layer； 1. Double-layer molecular sieves are more energy-efficient ； Molecular sieves have a stronger ability to adsorb water than alumina, which means more energy is required for desorption. Desorbing water from molecular sieves 1000KCAL/kg ； The water desorbed from alumina is 750 KCAL/kg; 2. The alumina layer serves to protect the molecular sieve. Although molecular sieves can adsorb water, this refers to water vapor in the air; liquid free water can cause damage to molecular sieves. Even if only molecular sieves are used in the process to absorb water vapor, an alumina layer to prevent oxidation by liquid water must still be added before the molecular sieves. So, are there any disadvantages to this design? Or there may be other advantages.
Reduce investment, as activated alumina is much cheaper than molecular sieves.
The effective operating time of a dual-bed system is increased by 25%~35% compared to a single-bed system, which extends the service life of the molecular sieve and makes regeneration more energy-efficient. However, the ratio of the two beds should match the operating conditions as closely as possible; otherwise, it will affect the purification efficiency. The two types of adsorbents in a dual-bed system are placed within the same casing, and the interface between them must be isolated to prevent mixing. The separation mesh not only makes it difficult to load and unload the adsorbents and increases resistance but also requires consideration of thermal expansion and contraction issues, otherwise leakage may occur.
I learned it! ~~~~~~~~~~~~~~~~~~~
The hardness of activated alumina is higher than that of 13X molecular sieve; allowing air to come into contact with it first during the pressurization of the purification system helps to protect the molecular sieve.
Active alumina is cheaper, and its decomposition temperature is lower, which allows for a reduction in the thermal load on air separation heaters or steam heaters; this in turn saves electricity and steam, achieving energy conservation and reduced consumption.