How to judge activated alumina is out of valid?
Time:2025-06-07
Activated alumina is an efficient desiccant for deep drying of trace amounts of water, suitable for non thermal regeneration devices, which have wide application in the industrial field.
Below several methods to determine whether activated alumina is out of valid:
* Appearance changes: Alumina oxide will gradually lose its original white color during use, and its color will turn yellow or brown, even clump or become damp. When these changes are observed, it’s out of work.
* Moisture absorption performance: Place a certain amount of activated alumina ball in a constant temperature and humidity environment to observe whether its ability to adsorb moisture decreases. If the adsorption capacity is significantly reduced, it’s out of work.
* Chemical properties: The main component of activated alumina is Al2O3, which has a certain chemical stability. But as the usage time increases, its surface may be covered by moisture and other impurities, which lead to the change in chemical properties.
So which factors will affect the shelf time?
* Usage environment: If the humidity is high, activated alumina is prone to failure. Therefore, it should be stored in a dry and ventilated environment, avoiding direct sunlight and humidity.
* Usage quantity: Insufficient usage will cause activated alumina ball to lose its adsorption capacity quickly. The appropriate dosage should be selected according to actual needs.
* Chemical factor: Avoid contact with other chemical substances to prevent chemical reactions that may cause be out of work. Meanwhile, avoid placing it in high temperature or high pressure environments to prevent damage to its structure.
How long does it take to replace under normal circumstances?
The replacement cycle of alumina balls is not fixed and is influenced by various factors, including usage environment, quality, regeneration method, etc. However, a rough range of replacement cycles can be provided based on general situations and different application scenarios:
The shelf life of alumina balls is usually between 12~20 months, and some data also show it can reach 1~3 years. The specific service life still needs to be determined based on the actual situation.
1. Air compressor drying system
Generally, in the air compressor drying system, the replacement time for alumina balls is usually 3 months. This is because the working environment of the air compressor is relatively harsh, and the alumina balls are easily adsorbed and saturated, resulting in a significant decrease in moisture absorption and dryness.
If high-quality alumina balls are used, their service life can be extended to about 1 year.
2. Fluoride removal through water treatment
Replacement frequency: The replacement frequency of alumina balls in water treatment for fluoride removal depends on changes in fluoride content. When alumina balls adsorb a large amount of fluoride ions, their fluoride removal ability decreases, and replacement or regeneration treatment is needed at this time. Generally speaking, replacement or regeneration may be necessary after 3 to 5 years of use.
Regeneration treatment: In water treatment for fluoride removal, activated alumina can be regenerated to restore their adsorption performance. It is recommended to undergo regeneration treatment every six months to extend the service life.
3. Catalyst carrier
When used as a catalyst carrier in the petrochemical industry, the shelf life of alumina balls is generally long, up to 3 to 5 years.
4. Other applications:
* Air separation industry: The working environment is relatively good, and it is generally used for 2 to 3 years.
* Hydrogen peroxide production: The acidity and alkalinity of the working fluid are relatively poor, and the working conditions are relatively poor. Generally, it needs to be replaced after 3 to 6 months of use.
Air adsorption dryers are familiar in the chemical industry, and their core components are adsorbents , such as activated alumina, molecular sieves, silica gel. They adsorb water and gas through a porous structure, and their performance affects the drying effect directly. As the adsorption regeneration cycle progresses, the adsorption capacity gradually decreases and needs to be replaced regularly to ensure stable system operation.
The replacement cycle is usually 3-5 years, but it needs to be adjusted based on the following factors:
1. Frequency of use: High frequency use will accelerate the saturation of the adsorbent, and the cycle needs to be shortened; Long term high load operation will accelerate the decline of adsorbent performance;
2. Environmental humidity: The higher the humidity of the inlet air, the greater the adsorption load and the corresponding decrease in lifespan; High temperature, high dust and other harsh environments may require early replacement.
3. Operating parameters: Abnormal pressure or increased dew point temperature may indicate adsorbent failure.
Meanwhile, during work, it is important to pay attention to the following matters:
1. Monitoring indicators: Regularly monitor the dew point temperature at the outlet, and if it continues to exceed the standard, check the status of the adsorbent.
2. Replacement operation: Thoroughly clean the adsorption tower during replacement to avoid mixing of new and old adsorbents; The filling should be evenly compacted to prevent air flow short circuits.
3. Selection matching: The new adsorbent should be consistent with the prototype number to ensure that the porosity and mechanical strength meet the requirements.
4. Regeneration inspection: After replacement, verify the regeneration effect and confirm that the heating temperature and cooling time are normal.
So how to choose the right adsorbent for an adsorption dryer?
1) Molecular sieve: It is a crystal structure with uniform pore size and strong adsorption ability for water molecules, especially suitable for precision industrial scenarios with dew point below -60 ℃. However, due to its low strength, it is easy to be pulverization under high-intensity compressed air impact, so it can only be used in small quantities in traditional twin tower adsorption dryers.
2) Activated alumina: It is a high-strength adsorbent and the most widely used adsorbent in adsorption dryers currently. It can withstand the high-pressure impact of compressed air without powdering. Excellent performance in moderate humidity environments, suitable for places with dew point below -40 ℃, with a regeneration temperature 30-50 ℃ lower than molecular sieves.
3) Silica gel adsorbent: It’s getting less and less in compressed air drying. It is only suitable for drying at room temperature and is used in pressure dew point environments of -20 ℃.
In terms of drying performance, molecular sieves are much stronger than activated alumina, but the replacement cost is higher. Therefore, before choosing which adsorbent, it is necessary to understand the user's requirements or expectations for dew point, so as to choose the best solution that can meet the user's requirements and reduce the cost of use.
