Two types of air dryer including refrigerated air dryer and desiccant dryer, below introduced their working principles, advantages, and the best air compressor dryer manufacturers.
What is air dryer for compressor
An air dryer is a device used to remove moisture from compressed air. There are mainly two types of air dryers: desiccant air dryer and refrigerated air dryer. Refrigerated air dryer uses the principle of cooling air and lowering air temperature to condense moisture from wet air and obtain drier air.
Desiccant air dryer uses the principle of pressure swing adsorption(PSA) and thermal swing adsorption(TSA). When wet air passes through the adsorbent, the moisture is adsorbed by the adsorbent to obtain dry air.
Refrigerated air dryer
Working principle of refrigerated air dryer
The high-temperature compressed air saturated with water first enters the front and rear coolers of the refrigerated air dryer. The compressed air passing through the evaporator exchanges heat with the refrigerant, and the heat in the high-temperature compressed air is taken away, and the temperature is reduced.
After that, the compressed air enters the high-efficiency heat exchanger, and the compressed air is quickly cooled to 2 – 8℃ in the heat exchanger.
(Refrigerated air dryer)
At this time, the water molecules in the compressed air will condense and precipitate, and enter the high-efficiency three-stage air-water separator together.
The low-temperature air is separated by a first-stage high-speed rotation in the air-water separator, and then enters the second-stage super gravity separation section, and then enters the fine partition separation section for fine separation of water.
The separated condensed water will be discharged from the system through the fully automatic drainage device, and finally dry compressed air is obtained.
The air pressure dew point of refrigerated air dryers can be as low as 2℃. The cold dry compressed air flows through the air heat exchanger, absorbs the heat of the inlet and outlet compressed air, and after the compressed air is frozen and separated, the dry compressed air enters the reheater, which can further raise the outlet air temperature to 15 – 40℃ after drying. Ensure outlet air temperature is appropriate to prevent condensation.
Types of refrigerated air dryers refrigerants
Refrigerant R22
Also known as Freon and HCFC-22 Freon, it is a colorless, odorless, non-flammable, and non-explosive safe refrigerant, whose boiling point is -40℃ under standard atmospheric pressure (0.1MPa)
But since its release into the earth’s atmosphere will cause harm to the ozone layer, refrigerant R22 is now being phased out and replaced by other environmentally friendly refrigerants.
R134a
R134a is a hydrofluorocarbon (HFC) refrigerant used in automotive air conditioners, and can replace R12 and R22 used in medium and high temperature refrigeration equipment (such as commercial and household refrigeration and cooling devices).
R410a
R410a is a new type of environmentally friendly refrigerant that does not damage the ozone layer, and its working pressure is about 1.6 times that of ordinary R22 air conditioners.
R410a is internationally recognized as the most suitable refrigerant to replace R22, and has been popularized in Europe, America, Japan and other countries.
R407c
In modern refrigeration technology, R407C refrigerant (a mixture of R-134a, R-125 and R-32) can provide stable refrigeration under various operating conditions with its moderate evaporation temperature and good thermophysical properties.
Whether in household air conditioning, commercial refrigeration equipment or industrial cooling systems, R407C can meet different needs.
When choosing a refrigerated air dryer suitable for your application, you also need to consider choosing a suitable refrigerant. Different refrigerants have different performance and prices.
Refrigerated air dryer maintenance
When cleaning the condenser of refrigerated air dryers, avoid damaging the wing surface. The surrounding area should be adequately ventilated and heat-dissipated to avoid direct sunlight.
Regularly use compressed air to remove dust on the surface. The flow rate and pressure of compressed air should not be too large.
Regularly observe the drainage and sewage systems, and clean the cooling water and compressed air systems.
Regularly check the refrigeration system and electrical control system, and clean the inside of the condenser.
(Refrigerated air dryer maintenance)
Advantages of refrigerated air dryer
Efficient dehumidification: Refrigerated air dryers condense the water vapor in the compressed air into droplets through cooling and discharge it out of the machine through the automatic drainage system, thereby effectively reducing the moisture content and ensuring the dryness of the compressed air.
Prevent secondary condensation: As long as the ambient temperature of the downstream pipeline at the dryer outlet is not lower than the dew point temperature of the evaporator outlet, secondary condensation will not occur, avoiding problems such as condensation, dripping, and rust in the pipeline.
Simple structure and easy maintenance: Refrigerated air dryers usually include front and rear coolers, high-efficiency cross-flow heat exchangers, three-stage air-water separators, and fully automatic drainage devices. The structure is relatively simple and maintenance is relatively convenient.
Wide applications: Refrigerated air dryers are widely used in various pneumatic equipment, pneumatic tools, spray painting, food packaging, textiles, chemicals and other industries in industrial production, and can meet the needs of different fields.
Energy saving and environmental protection: Refrigerated air dryers reduce energy consumption through efficient dehumidification process, while avoiding the problem of secondary condensation, which helps to save energy and reduce emissions and meet environmental protection requirements.
In summary, Refrigerated air dryers play an important role in industrial production with its advantages of efficient dehumidification, prevention of secondary condensation, simple structure, convenient maintenance, wide application, energy saving and environmental protection.
Desiccant air dryer
Desiccant air dryer working principle
The working principle of desiccant air dryer is based on the change of pressure and temperature (PSA and TSA principles). The ability of air to hold water vapor is proportional to its pressure. During the drying process, part of the air is decompressed and expanded to atmospheric pressure. This pressure change makes the expanded air drier.
(Heatless desiccant air dryer)
The dry regenerated air flows through the adsorbent layer. The principle of different volumes of water molecules and air molecules is used to use gas purification special adsorbents or molecular sieves to adsorb saturated water vapor in the compressed air.
The water molecules can be easily retained in the molecular sieve particles, and then the regeneration method is used to restore the molecular sieve.
(Desiccant air dryer working principle)
The adsorbents of desiccant air dryers generally include activated alumina, silica gel, and molecular sieves. The dew point of compressed air treated by desiccant air dryer can easily reach -40℃.
The pressure dew point range of common desiccant air dryers on the market is generally -40℃ ~ -70℃.
Air compressor dryers filters
As the industrial main body of desiccant air dryers, the adsorbent is subjected to frequent shocks of pressure, water vapor and heat for most of the time, and is easily mechanically broken and contaminated by the medium, which deteriorates the performance of the adsorbent.
Therefore, the oil content of the compressed air entering the desiccant air dryer should be controlled below 0.01ppm.
In view of the fact that oil-lubricated air compressors cannot remove all the oil in the compressed air, it is necessary to install an air compressor dryer filter at the air inlet of the dryer to prevent any trace oil from accumulating in the adsorption bed (this accumulation is very fast).
(Air compressor dryers filters)
Desiccant air dryers should be used under rated temperature and pressure conditions. When the inlet temperature or inlet pressure is higher or lower than the rated value, it should be corrected in time to avoid damage to the desiccant air dryer and the adsorbent or a decrease in the quality of the dry compressed air produced.
(High-efficiency compressed oil gas separator)
Types of desiccant air dryers
The common desiccant air dryers on the market can be classified into two types according to the adsorbent regeneration method: Heatless regenerative desiccant air dryer and heated regenerative desiccant air dryer.
Heatless regenerative desiccant air dryer
Heatless regenerative desiccant air dryers use the PSA principle that sieve capacity increases with increasing pressure to absorb moisture to achieve the purpose of dehumidification. The two towers work in a cycle without the need for additional heat sources, and continuously provide dry gas to the user’s gas system.
Heatless regenerative desiccant dryers have the characteristics of small size, simple process flow, low investment, easy use and maintenance, automatic control, and energy saving. They are widely used in chemical, light industry, telecommunications, petroleum, textile and other industries for pneumatic control, pneumatic instruments, pneumatic components, and industrial gas in various industries to provide dry compressed air.
Heated regenerative desiccant air dryer
One adsorption tower of the heated regenerative desiccant air dryer performs adsorption drying under working pressure, while the other adsorption tower extracts a very small amount of compressed air from the main pipeline and undergoes a decompression and heating process as regeneration gas to perform heated regeneration on the adsorbent.
The residual water content of the desiccant after thermal regeneration is greatly reduced, which increases the processing capacity of the device.
Heated regenerative desiccant air dryers can stably maintain low pressure dew point, and the dual tower working switching cycle is 60-80 minutes. In addition, a gas diffusion device is used to make the airflow in the tower evenly distributed without channeling. The outlet air pressure dew point can reach -40 – 70℃.
Advantages of desiccant air dryer
The advantages of desiccant air dryer mainly include the following aspects:
Efficient drying: Desiccant air dryers can effectively remove moisture from compressed air through the adsorption of adsorbents, significantly reducing the humidity of the air, and the dew point can reach -40℃.
Environmental protection and energy saving: Desiccant dryers adopt physical methods for drying, do not require the use of any chemicals, do not produce any harmful substances, comply with environmental protection requirements, and have low energy consumption and low operating costs.
Stable and reliable operation: Desiccant dryers have a simple structure and are easy to maintain. It does not require the use of any chemical refrigerant, does not produce any harmful substances, meets environmental protection requirements, has low energy consumption, long service life of the adsorbent, stable equipment operation, and low failure rate, and is suitable for continuous or intermittent production needs.
Wide range of application: Desiccant air dryers are suitable for a variety of industrial fields, such as air compression systems in automobiles, machinery, electronics, chemical industries, etc., as well as environmental protection engineering, laboratories, and medical care.
Easy maintenance: The daily maintenance of Desiccant air dryers mainly includes cleaning the filter and checking valves, etc. It is simple to operate and has low maintenance cost.
In summary, desiccant air dryers adopt the principles of pressure swing adsorption and thermal swing adsorption, are widely used in many fields such as industrial production and laboratories due to their high efficiency, environmental protection, stability and reliability.
Best air dryer for air compressor
There are many manufacturers of the best air dryer for air compressor, below are some references:
Atlas Copco: Atlas Copco is a well-known Swedish brand with more than 150 years of history and is a global leader in compressor technology. Its compressed air dryers are known for their high reliability, low energy consumption and high energy efficiency, and are widely used in many countries and regions around the world.
Ingersoll Rand: Ingersoll Rand originated in the United States and is a world-renowned air compressor manufacturer. Known for their durability and high performance, their compressed air dryers are suitable for a variety of industrial needs, from small portables to large industrial equipment.
Kotech Group: Kotech is a professional air compressor manufacturer in the UK that focuses on technological innovation and high efficiency. Its compressed air dryer adopts advanced energy-saving technology, and its advantages include energy saving, environmental protection, and high-quality drying results. Suitable for a variety of work environments, especially businesses that focus on energy efficiency.
Quincy: Quincy was founded in the United States. It has a wide range of dryer products, including refrigerated air dryer, regenerative dryer and desiccant air dryer. Quincy dryers are known for their stable quality and diversified product lines. They are suitable for various industrial application scenarios and meet the needs of customers in different industries.
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