Requirements and Applications of Activated Alumina
Time:2025-09-15
In recent years, the basic chemical materials market in domestic has experienced a resurgence. As an indispensable adsorbent, desiccant and catalyst carrier in multiple key industrial fields, the price of aluminum hydroxide material -- the main raw material of activated alumina, continues to rise, leading to cost pressures on downstream activated alumina balls and attracting widespread attention in the industry. Under the dual tests of cost and market, the quality stability and efficient application of products have become the focus of attention in the industry chain.
Since the second half of last year, the price of industrial grade aluminum hydroxide, as the core raw material for producing activated alumin, has shown a continuous upward trend. According to industry market analysis agencies, as of now, the cumulative increase has exceeded 15%. Market analysts pointed out that the price increasing this time is mainly influenced by multiple factors:
1. Upstream supply tightening: The adjustment of bauxite mining policies and the increase in environmental requirements have led to a tightening of the supply of primary raw materials for aluminum hydroxide.
2. Energy cost driven: The production of activated alumina requires high-temperature calcination, which is a high-energy consumption process. The recent fluctuations in energy prices such as coal and natural gas have directly pushed up production costs.
3. Strong market demand: The demand for high-performance activated alumina in downstream fields such as new energy and environmental protection continues to grow, supporting raw material prices from the demand side.
Under cost pressure, the market has put forward higher requirements for the quality of activated alumina products. High quality activated alumina is not simply a powder, its specific surface area, pore volume, compressive strength, adsorption efficiency and other indicators are crucial.
*High specific surface area and controllable pore structure provide a huge adsorption space and reaction interface, which is the basis for its function as an efficient adsorbent and catalyst carrier.
*High mechanical strength and wear resistance: Ensure that it is not easily powdered in industrial environments with high pressure and high airflow erosion, prolong its service life, and reduce losses.
*Stable chemical properties: It has good thermal stability and corrosion resistance, and can maintain performance in various harsh chemical environments.
Using inferior products may seem to save short-term costs, but due to their low adsorption efficiency, short lifespan, and susceptibility to pulverization, system blockages can actually lead to frequent shutdowns and replacements, resulting in a much higher overall cost than using high-quality products.
Despite facing cost challenges, the application scope of activated alumina in modern industry is still expanding due to its unique physical and chemical properties, and it is known as the "industrial monosodium glutamate".
1. Adsorption and drying field -- largest application in the market:
*Petrochemical industry: Used for deep drying of gases such as cracking gas, ethylene, propylene, etc., to remove moisture and protect downstream catalysts.
*Air separation industry: Adsorb moisture in oxygen and nitrogen production equipment to prevent device freezing.
*Instrument air/compressed air: Removes water vapor and oil from compressed air to ensure the normal operation of pneumatic tools and instruments.
2. Water treatment field (driven by environmental demand growth):
*Defluorination agent: It is currently the most widely used fluoride removal material for drinking water, which can effectively reduce the fluoride content in high fluoride water to below the safety standard, and is crucial for ensuring the safety of residents' drinking water.
*Arsenic adsorbent: can be used to remove arsenic pollution from groundwater.
3. In the field of catalysts and their carriers (high value-added applications):
*As the main catalyst, it is used for the production of hydrogen peroxide by anthraquinone method.
*As a catalyst carrier, it is widely used in processes such as automobile exhaust purification, hydrogenation refining, and sulfur recovery, and its performance directly determines the efficiency of catalytic reactions.
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.
