Compressed Air Treatment Challenges: Core Pain Points from Filtration to Drying

Compressed Air Treatment Challenges: Core Pain Points from Filtration to Drying

Filters are used to filter out solid particles, oil droplets and part of the liquid water for preliminary treatment of compressed air. In traditional filters, the lower end of the filter element is blocked, so impurities will accumulate inside the filter element, penetrate through the filter element to the bottom of the filter chamber, and then be discharged through the automatic drain.

Main Problems

Solid particles cannot penetrate out of the filter element and will adhere to the inner wall, increasing the resistance of compressed air. Water droplets and oil droplets in the process of penetration may be re-entrained by the compressed air.

Compressed Air Refrigerated Drying

Refrigerated dryers are mainly used to cool high-temperature compressed air, reducing the saturated moisture content from high temperature to low temperature. Part of the water will condense into liquid water and be discharged through the automatic drain valve.

Main Problems

Limited by its working principle and structure, the refrigerant evaporation temperature of a refrigerated dryer cannot be lower than 2°C, otherwise freezing will block the pipeline. Restricted by heat exchange efficiency and water separation efficiency, the actual outlet dew point cannot reach the evaporator set value. To achieve a lower dew point, the power of the refrigerant compressor must be increased, which not only increases the procurement cost but also the operating cost of the refrigerated dryer. At present, the actual measured dew point in most applications is between 20°C and 35°C, with a large amount of liquid water entrainment.

Compressed Air Adsorption Drying

Based on the water absorption characteristics of desiccants, moisture in compressed air is adsorbed under high partial pressure and regenerated under low partial pressure through the principle of pressure swing adsorption for recycling, so as to obtain dry compressed air. Generally, the pressure dew point can reach -20°C to -70°C.

Main Problems

At present, double-tower or combined double-tower adsorption dryers are mainly used in China. The main problems are difficult compact filling of desiccants, easy channeling effect leading to substandard performance, high energy consumption, and difficult secondary replacement and filling of desiccants.