Adsorption properties of molecular sieves
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The adsorption properties of molecular sieves can be explained as follows: they have good stability and can maintain their normal adsorption capacity even at temperatures below 200°C. But in fact, we say that if the temperature of the air entering the molecular sieve increases, its adsorption efficiency and capacity decrease. How can this be explained?
It should mean that at 200 degrees, the molecular sieve is not damaged and does not become permanently ineffective
The rise in temperature leads to an increase in moisture content, thereby increasing the load on the molecular sieve. The adsorption capacity decreases as the temperature rises. Adsorption is an exothermic process; as the temperature increases, the thermal motion of the molecules of the adsorbate intensifies, resulting in an increase in the number of molecules that detach from the adsorption surface and return to the gas phase. Thus, the adsorption efficiency is reduced.
An increase in temperature only affects the adsorption efficiency, as higher temperatures result in higher moisture content. At 200°C, it is still the \"adsorption capacity\" that is maintained, rather than the adsorption efficiency; these two concepts should be distinguished from each other. It means that the adsorption capacity at 200°C is the same as that at the normal operating temperature.
The adsorption capacity of the adsorbent is related to the temperature and pressure of the feed gas; as the temperature increases, the adsorption capacity decreases, and vice versa； The higher the pressure, the stronger the adsorption capacity; conversely, the adsorption capacity decreases ； 200 degrees refers to the heating temperature for regeneration; currently, air separation units are generally heated to around 175 degrees, with a peak cold-blow temperature of around 90 degrees, which is sufficient to ensure complete regeneration.
What is the preceding text? Does the 200 degrees here refer to the regeneration temperature?
“The adsorption capacity at 200°C is the same as that at the normal operating temperature. . . . ” Is this sentence correct? Worth pondering............
Look at the question: it can maintain normal adsorption capacity at 200°C. Bro, can you tell me what this sentence means?
It’s just a normal discussion; everyone should express their opinions freely, without any verbal attacks. It’s sufficient to use each other’s strengths to compensate for weaknesses. I too found the wording ambiguous while delving into it, which is why I had a question once. I learned a lot from everyone’s answers!
I agree with Haiyou on the 4th floor. Under normal operating conditions, the adsorption capacity remains constant; however, high moisture content at high temperatures may cause problems such as the pulverization of the molecular sieve.
All are experts! That’s amazing, you’ve learned it.