Membrane PSA: [Weekly Topic] {November 13, 2011} What are the methods for regenerating adsorbents?
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This post was last edited by Kongfen Zhulong on 2011-11-30 at 11:28. The Membrane Separation and PSA Discussion Forum is launching a “Weekly Topic” series on the basics of PSA pressure swing adsorption; we invite all forum members to participate actively. Purpose of the activity: To deepen the knowledge already acquired, and to improve and strengthen the basic theoretical knowledge of all participants through answering questions, thereby reinforcing what they already know and helping them recall what they have forgotten. There must be a reward for the participants. Question: What are the methods for regenerating adsorbents? Please unhide the hidden post downstairs; our forum does not allow posts to be visible only after hiding replies within the weekly topic. Please learn *our forum rules!
This post was last edited by Kongfen Zhuleng on December 2, 2011, at 08:37. The main methods are as follows: 1. Pressure reduction: The adsorbent bed adsorbs substances under higher pressure; then the pressure is lowered to a level close to atmospheric pressure. At this point, a portion of the adsorbed components is desorbed. This method is simple to operate, but its drawback is that the desorption of a single adsorbed component is insufficient. Regeneration of the adsorbent: After the adsorption bed is reduced to atmospheric pressure, vacuuming is used to lower the pressure in the adsorption bed in order to achieve better regeneration results; however, this approach increases energy consumption. 3. Flushing: A weakly adsorbing component or some other appropriate gas is passed through the adsorption bed that needs to be regenerated; as the flushing gas flows through, the partial pressure of the adsorbed component decreases. The degree of regeneration of the adsorbent depends on the amount and purity of the purge gas. 4 Displacement: Using a gas with stronger adsorption capacity to displace the originally adsorbed component from the adsorbent. This method is commonly used in cases where the product components have a strong adsorption capacity while the impurity components do not, that is, to obtain the product from the adsorbed phase. During the pressure swing adsorption process, the regeneration method to be used is determined based on the properties of the various components in the gas to be separated, the requirements for the product, the characteristics of the adsorbent, and the operating conditions; usually, a combination of several regeneration methods is employed. It should be noted that regardless of the regeneration method used, at the end of the regeneration process, the remaining amount of the adsorbent in the adsorption bed will not be zero; in other words, it is impossible to completely regenerate the adsorbent in the bed. This residual amount is also not evenly distributed throughout various parts of the adsorption bed.
1. Regeneration of 5A adsorbent after absorbing water: heating with hot air (or purified gas). 2. Adsorption of high-pressure carbon dioxide by silica gel: reducing pressure or evacuating. 3. Adsorption of gold by activated carbon: flushing with counterflow air； 4. Towels to absorb grease: hot water + soap
Heating regeneration method, distillation method, chemical regeneration method, chemical oxidation regeneration method, biological regeneration method
I’m not sure; please reply with school*. Activated carbon can be regenerated with steam and then dried. I’m not familiar with molecular sieves, but is it necessary to regenerate silica gel and aluminum oxide?
The regeneration of adsorbents is related to the adsorption process: 1. Regeneration of 5A adsorbents after absorbing water: heating with hot air (or purified gas); 2. Adsorption of high-pressure carbon dioxide by silica gel: reducing pressure or evacuating; 3. Adsorption of gold by activated carbon: flushing with counterflow air； 4. Towels to absorb grease: hot water + soap
Reply 1# QQNeverGivesUp: Heating, purging, negative pressure
(1) Heating regeneration method, mainly including: dehydration — filtration to dryness； Drying — 100–150. C. Evaporation of water, separation and volatilization of low-boiling substances ； Carburization — 300～700. C – Degradation, carbonization, activation of organic substances ； Activation – 700–1000°C; pore reconstruction and cooling – rapid quenching with water to prevent oxidation. (2) Distillation method: Water vapor is introduced for stripping, with the amount of vapor being 3 to 5 times that of the adsorbate. • (3) Chemical regeneration method: After treating chromium-containing wastewater with activated carbon, it is soaked in 10% sulfuric acid to convert hexavalent chromium into trivalent chromium, which is then eluted. It can also be converted using sodium hydroxide and eluted as sodium chromate. Phenol removal using activated carbon, followed by leaching with 10% sodium hydroxide. Common solvents used in chemical synthesis mainly include acids, bases, benzene, propylene, aldehydes, alcohols, etc. (4) Chemical oxidation regeneration methods include wet air oxidation regeneration and ozone oxidation regeneration. (5) Biological regeneration method, which involves the use of biological activated carbon.
Are there anything else besides TSA and PSA?
Vacuum, flushing, replacement, temperature change