How to solve the problem of water in the air from the air compressor

The water content of the compressed air output by the air compressor is a common problem, which is mainly formed by the condensation of water vapor in the air during the compression process. If not treated in time, moisture may cause equipment corrosion, pneumatic component failure, product quality degradation and other issues. The following is a systematic solution, covering cause analysis, treatment and prevention methods:

the Core Cause of Water Content in 1. Compressed Air

1. air compression temperature rise
   when the air is compressed, the temperature increases and the water vapor saturation increases; when the compressed air is cooled below the dew point, the water vapor condenses into liquid water.

2. Influence of environmental humidity
   under high temperature and high humidity environment, the air has higher water content, and the amount of condensed water after compression increases significantly.

3. Insufficient post-processing
   drying equipment (such as cold dryers and suction dryers) is not configured or properly maintained, resulting in ineffective removal of moisture.

2. solution: phased treatment of compressed air moisture

1. Primary treatment: internal drainage of air compressor

• automatic drain valve
  install an automatic drain valve at the bottom of the air compressor air tank to drain the condensate regularly (it is recommended to drain it every 4-8 hours, or adjust it according to humidity).
  Attention: It is necessary to regularly check whether the drain valve is blocked to avoid water flowing back to the pipeline.

• Heat preservation of gas storage tank
  the outer wall of the gas storage tank is wrapped with thermal insulation material (such as rubber sponge) to reduce the external cold air contact and reduce the risk of condensation.

2. Intermediate treatment: after cooler and filter

• after cooler
  air-cooled or water-cooled after-cooler is installed at the outlet of the air compressor to reduce the temperature of the compressed air to within 5 ℃ of the ambient temperature to condense most of the water vapor.
  Example: If the ambient temperature is 30 ℃, the outlet temperature of the after cooler shall be ≤ 35 ℃.

• Gas-water separator
  A cyclone or baffle type air-water separator is installed after the after-cooler to separate liquid water through centrifugal action, and the separation efficiency can reach more than 90%.

• Pre-filter
  install a 5μm grade coarse filter to intercept large particles of liquid water and impurities to protect subsequent drying equipment.

3. Depth treatment: drying equipment

• freeze dryer (cold dryer)
  • principle: The compressed air is cooled to 2-10°C through the refrigeration system, so that the water vapor is condensed into liquid water and discharged.
  • Applicable Scenarios: General industrial scenarios where the dew point requirement is not strict (pressure dew point ≥ 3 ℃).
  • Selection recommendations: The processing capacity should be slightly larger than the air compressor displacement (such as 10% redundancy) to avoid overload operation.
• Adsorption dryer (suction dryer)
  • principle using activated alumina or molecular sieve to adsorb water vapor, the pressure dew point can reach -40 ℃ to -70 ℃.
  • Applicable Scenarios: High requirements for dryness (such as electronics, pharmaceutical industry) or low temperature environment.
  • Attention: The adsorbent needs to be replaced regularly (usually every 2-3 years), and the pre-filter is configured to prevent oil pollution.
• Membrane dryer
  • principle: Separate water vapor through a selectively permeable membrane without consuming refrigerant or adsorbent.
  • Applicable Scenarios: Small equipment or mobile air compressor, but the processing capacity is small.

4. Terminal treatment: precision filtration and drainage

• precision filter
  install a 1μm or 0.01μm precision filter after the dryer to intercept residual moisture and tiny particles to ensure the quality of compressed air.

• Electronic drainer
  install an electronic drain at the low point of the pipeline to automatically drain the water through timing or pressure sensing to avoid manual operations.

3. precautions: reduce moisture generation

1. decrease intake air temperature
   • install an air intake filter at the air inlet of the air compressor and make sure that the air inlet is away from heat sources or humid areas.
   • If the ambient temperature is too high, consider installing an intake air cooling device (such as an evaporative cooler).
2. Control ambient humidity
   • install a dehumidifier in the air compressor room to control the relative humidity below 60%.
   • Avoid running the air compressor for a long time in rainy or humid environment.
3. Regular maintenance
   • clean the air compressor cooler every 500 hours to prevent dust blockage from affecting heat dissipation.
   • Check whether the after-cooler, gas-water separator and drain valve are unblocked, and clean up the scale in time.
4. Optimized piping design
   • the compressed air pipeline should be inclined to the drainage point (slope ≥ 1/100) to facilitate the natural discharge of condensed water.
   • Avoid sharp bends or dead corners of the pipeline to reduce moisture accumulation.

4. solutions for typical application scenarios

5. common problems and troubleshooting

1. the dryer outlet still contains water
   • check whether the refrigeration pressure of the refrigerator is normal (usually 0.5-0.7MPa). If the pressure is low, the refrigerant may leak.
   • Whether the adsorbent of the suction dryer is invalid (dark color or caking), it shall be replaced in time.
2. Automatic drain valve does not drain
   • check whether the solenoid valve of the drain valve is energized, or manually test the drain function.
   • Clean up the impurities inside the drain valve to avoid the valve core sticking.
3. Accumulation of water in the pipeline
   • check whether the pipe slope meets the requirements, or install the low point drain valve.
   • In winter, the pipeline should be insulated to prevent icing and blockage.