Stainless Steel Desiccant Air Dryer

_{[1]Adsorption Dryer}Equipment for Reducing Moisture Content in Compressed Air

Adsorption dryers utilize advanced chemical technology, operating on the principle of using specialized molecular sieves for gas purification to filter out saturated water vapor from compressed air by leveraging the difference in volume between water and air molecules. This easily adsorbs water molecules within the molecular sieve granules, and the molecular sieve is then regenerated through a regeneration method, allowing the dew point of the compressed air to easily reach -40°C.

Adsorption dryers achieve drying through "pressure changes" (pressure swing adsorption principle). Since the capacity of air to hold water vapor is inversely proportional to pressure, a portion of the dried air (called regeneration gas) is减压 expanded to atmospheric pressure. This pressure change makes the expanded air drier, which then flows through the desiccant bed that needs regeneration (i.e., the drying tower that has absorbed sufficient moisture). The dry regeneration gas absorbs the moisture from the desiccant and carries it out of the dryer to achieve dehumidification. Two towers work in循环, requiring no heat source, and continuously supply dry compressed air to the user's system.

Precautions

The oil content in the inlet air should be controlled below 0.01 PPM;鉴于 oil-free air compressors cannot achieve true oil-free operation, to prevent微量 oil accumulation in the adsorption bed (which accumulates quickly), it is necessary to install an oil remover at the dryer's inlet. Micro-heat regeneration dryers should be used under rated temperature and pressure conditions. When the inlet temperature is higher or the inlet pressure is lower than the rated values, capacity correction should be performed.

When micro-heat regeneration dryers are used with piston air compressors, a稳压 air receiver should be installed upstream to eliminate pulsating气流 impact on the adsorbent. Avoid deliberately "energy-saving" by reducing regeneration gas consumption (including regeneration gas volume and heating power). When a "refrigerated dryer is installed upstream," the connection between the micro-heat regeneration dryer and the refrigerated dryer should, if space permits, be installed separately to reduce air pressure drop, improve the refrigerated dryer's ventilation conditions, and facilitate daily maintenance. When the air supply is sufficient, non-heat regeneration dryers should be首选, as their comprehensive energy consumption is not higher than that of heated regeneration, and they offer a lower and more stable dew point.

Based on the adsorbent regeneration method, they can be mainly classified into non-heat regeneration micro-heat regeneration dryers and heated regeneration micro-heat regeneration dryers. Non-heat micro-heat regeneration dryers operate on isothermal adsorption, also known as "pressure swing adsorption." Heated micro-heat regeneration dryers operate on isobaric adsorption, also known as "temperature swing adsorption." In practice, there is also a type called micro-heat dryers. In form, micro-heat regeneration dryers also heat the regeneration gas, but since they use regeneration gas from their own dry air with very low moisture content, they also fall under the category of "pressure swing adsorption" dryers [1].

1. Design

A large adsorbent bed with a contact time of 6.25 seconds ensures that saturated air entering the dryer is dried to the required dew point and compensates for the natural aging of the adsorbent layer.

A reliable large stainless steel airflow diffuser ensures uniform airflow through the adsorbent layer, eliminating channeling.

Appropriate tower dimensions and upstream drying with downstream regeneration对流 help reduce regeneration gas consumption and avoid adsorbent fluidization and contamination.

Slow and complete pressurization procedures and delayed switching designs eliminate downstream airflow pulsation and prevent adsorbent movement and abrasion.

Independent filling and discharge ports facilitate adsorbent replacement.

Tower manufacturing complies with national pressure vessel standards.

2. High-performance activated alumina adsorbent

High compressive strength, abrasion resistance, high temperature resistance, non-hydrolyzing.

Large specific surface area and static adsorption capacity.

3. Effective performance

Symmetrical setup reduces noise叠加 effects.

Specially designed减压 box for easy installation and disassembly, with good noise reduction效果.

4. Imported pneumatic controller with high power and durability

Uses a two-position five-port pilot valve and deeply dried, filtered control air for precise control.

Dual-piston structure with high pneumatic power, reliable operation, and fast response.

Controller isolated from the main airflow to avoid moisture contamination.

5. Durable and reliable imported pneumatic butterfly valves for inlet and regeneration/repressurization

Elastomer valve seats and thin nickel-plated valve discs ensure leak-free operation and provide low pressure drop.

Valve stem bushings ensure smooth operation without field lubrication.

6. Regeneration gas flow control valve for precise flow adjustment

Unique balanced valve port design ensures precise adjustment.

Airflow always passes through the valve in the same direction, ensuring stable and consistent flow.

Separate setting of adjustment valve and orifice plate for easy control of regeneration gas flow.

7. Reliable check valve

Uses a soft valve seat to ensure proper closure, reduce wear, withstand high temperatures, and offer long service life.

8. Good safety and easy maintenance

Complies with pressure vessel standards.

Entire equipment is sandblasted and anti-rust treated to resist corrosion.

Nylon hose withstands pressure of 1.5 MPa (40°C).

Gauge connections can be used as valves for easy pressure gauge replacement.

Movable pipe connections for easy maintenance.

Vulnerable ComponentsTraditionally, the adsorbent, controller, and valves are collectively referred to as the four major vulnerable parts of the dryer.

① As the industrial main body of the dryer, the adsorbent withstands frequent impacts of pressure, moisture, and heat for most of the time, making it prone to mechanical破碎 and contamination by media, leading to performance degradation. Since activated alumina replaced silica gel as the primary adsorbent, various properties have greatly improved, especially compressive strength and resistance to liquid water immersion, reaching high levels. As long as operational factors like "insufficient regeneration energy" are avoided, the compressed air dew point can stably reach -40°C after treatment with activated alumina, with a lifespan of 2-3 years or more.

② The controller is the command center of the adsorption dryer. With the development of electronic technology and widespread application of PLC technology, control accuracy and reliability have qualitatively leapfrogged compared to early mechanical-electrical controls. Except for heating regeneration components needing further improvement in anti-interference and overload resistance, other control components are no longer considered vulnerable parts.

③ Control valves are relatively容易 damaged components in adsorption dryers. Frequent switching and long-term exposure to moisture and adsorbent脱落物 are major reasons for valve damage.

④ is a component that is more prone to malfunction, mainly manifested as blocked muffler exhaust channels.一旦 a fault (blockage) occurs, it can cause damage to the entire machine, leading to reduced adsorbent regeneration performance and premature aging. Therefore, it is a key focus of daily maintenance for adsorption dryers.