[Q&A Question 085] 2017.03.26
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This post was last edited by 955559 on 2017-7-21 22:29. [Q&A Question No. 085] 2017.03.26 What is the principle of PSA adsorption separation? The reference answers will be visible after responding; scoring is granted by identifying the key points. (Unless otherwise specified, all questions and answers are based on hydrogenation units.) ) Under different pressures, the adsorption efficiency of the adsorbent for various gases varies. 2017 Q&A Summary Thread (updates have begun) http://bbs.hcbbs.com/thread-1657793-1-1.html 2017 Daily Question Summary Thread (updates have begun) http://bbs.hcbbs.com/thread-1657794-1-1.html 2016 Q&A Summary Thread (updates completed) http://bbs.hcbbs.com/thread-1597792-1-1.html Third Phase of Haichuan’s Outstanding Management Members Selection Contest http://bbs.hcbbs.com/thread-1655902-1-1.html (Source: Haichuan Chemicals Forum)
When the gas is a mixture, the difference in the attractive forces exerted by the solid surface on different gas molecules results in a composition of the adsorbed phase that differs from that of the gas phase. It is this difference in density and composition between the gas phase and the adsorbed phase that forms the principle behind PSA adsorption separation.
Adsorbents have different degrees of absorption for the inhalation rate of the adsorbate
The goal of removing impurities is achieved by taking advantage of the fact that adsorbents have different adsorption capacities for various components at different pressures.
The adsorption capacity of the adsorbent for different media varies under different pressures; the separation of various media mixtures is achieved by alternating between different pressures
By taking advantage of the selective adsorption of gases by adsorbents – that is, the varying amounts of different gases (adsorbates) absorbed on the adsorbent, as well as the fact that the amount of a specific gas absorbed on the adsorbent changes with pressure – it is possible to separate gas mixtures and regenerate the adsorbent
For any type of adsorption, regarding the same gas to be adsorbed (adsorbate), at adsorption equilibrium, the lower the temperature and the higher the pressure, the greater the amount of adsorption. Conversely, the higher the temperature and the lower the pressure, the smaller the adsorption amount. Therefore, gas adsorption separation methods typically employ two cyclic processes: temperature swing adsorption or pressure swing adsorption. If the temperature remains constant and adsorption occurs under pressure, with desorption achieved by reducing pressure (vacuuming) or maintaining normal pressure, this is known as pressure swing adsorption.
Separation is achieved based on the different boiling points of the various components in the mixture, as well as the varying adsorption capacities of the adsorbent for these components