Why is air humid after compression

Why is air humid after compression

We all know the importance of compressed air drying. This is a critical step in the compressed air process. If you skip this step, it may cause a large amount of water to accumulate in your system. So why does compressed air get wet?

　　 The simplest answer is that there is always moisture in the air. Whether you can find moisture in the humid weather in Florida or the warm weather in Arizona, it's always there. Moisture is dispersed in the gas particles (mainly nitrogen and oxygen) in the ambient air in the form of water vapor molecules.

　　The interaction of air temperature, pressure and relative humidity determines the amount of water in vapor or liquid form. Let us look at an example.

　　 For example, a volume of air of 1m³ before compression can hold 23g of water at 77 degrees Fahrenheit and 60% relative humidity under a pressure of 1 bar(a), but the actual water content is 13.8g. Since the capacity is greater than the water content, there is no condensation in the system.

　　 When air is compressed, pressure and temperature will increase. When compressed to 7 bar (g), the air is 95 degrees Fahrenheit and the relative humidity is 100%. Saturated air can only hold 4.95g of water at this pressure and temperature, so 8.85g of water is successfully condensed.

　　 When purchasing a compressor system, please make sure you also purchase a dryer. Depending on the location and size of your facility, the system may terminate operation due to a large amount of water accumulation. If you only have a compressor system but no dryer, please contact our experts to design the most suitable dryer for your application