Key Points of Compressed Air Post-Treatment Equipment

Compressed air post-treatment equipment refers to a complete set of filtration and drying systems developed to remove fine solid particles, 

massive moisture and oil contained in compressed air discharged from air compressors. It includes compressed air receivers, compressed air filters (high-efficiency oil removal filters, 

precision filters), compressed air dryers (refrigerated air dryers, desiccant air dryers) and compressed air aftercoolers.

Compressed Air Filters
Function of Filters: Apart from moisture, compressed air contains oil, dust and various odor substances. Equipment that removes these contaminants in compressed air via physical separation is defined as a filter.
Filter Selection: Filters shall be selected step by step in accordance with the sequence of filtration accuracy grades. It is not allowed to select higher-grade filters directly without matching the preceding filter grades.
Compressed Air Dryers

Function of Refrigerated Air Dryers: Compressed air carries moisture at 100% relative humidity. Moisture will precipitate when the air cools down inside pipelines, 

causing numerous problems for air-consuming equipment. A refrigerated air dryer adopts refrigeration technology to forcibly cool compressed air down to 

the required dew point temperature (2–10°C). Water vapor inside the air condenses into liquid droplets and is discharged out of the unit via drainers.

Sizing of Refrigerated Air Dryers: Select a dryer with a processing capacity close to the volumetric flow of the air compressor and matching operating pressure. 

For industries requiring high-quality compressed air, refrigerated air dryers are not suitable; desiccant air dryers or combined dryers shall be adopted instead.

Desiccant Air Dryers work based on the pressure swing adsorption principle with a dual-tower structure. Adsorption towers are filled with desiccant (activated alumina). 

When compressed air flows through the tower and contacts the desiccant, air drying is realized through pressure swing adsorption, achieving a dew point below -40°C.

Sizing of Desiccant Air Dryers: The sizing principle is similar to that of refrigerated air dryers.
Air Receivers
Functions of Air Receivers:
a. Store compressed air;
b. Buffer pressure. The air pressure discharged by compressors fluctuates within a certain range. An air receiver stabilizes the compressed air pressure at the consumption side.

c. Pre-separate moisture. Part of the water vapor inside compressed air turns into liquid droplets after compression. Most droplets settle at the bottom of the air receiver. 

A blowdown valve installed at the bottom discharges condensate manually or automatically.

Sizing of Air Receivers: The rated pressure of the air receiver shall match the operating pressure of the air compressor. 

The recommended volume is 1/5 to 1/10 of the volumetric flow rate of the air compressor. If site conditions permit, a larger-volume air receiver is preferred for greater air storage capacity and superior...