On Compressed Air Treatment
In our modern industrial production activities, compressed air, as an important power source, has been widely used in various manufacturing process and equipment.
In our modern industrial production activities, compressed air, as an important power source, has been widely used in various manufacturing process and equipment. However, compressed air will be inevitably contaminated by various pollutants like water, oil, dusts and microorganism. These pollutants will not only affect the normal operation of equipment and lower production efficiency, but also cause severe influence to the production quality or even risk the safety production. So the effective purifying and treatment on compressed air is of great importance. We will discuss in this article, main pollutants, treatment methods, common treatment equipment and selecting suggestions so as to support clients thoroughly understand and master compressed air treatment.
High Pressure Oil Free Screw Air Compressor
Main Pollutants in Compressed Air
1. Water
From: the water vapor in the air, after being compressed, is condensed into liquid water.
Risk: water will cause pipeline corrosion, valve clamp, lubrication failure or even affect product quality.
2. Oil
From: During compressing, lubrication oil will be brought into compressed air system.
Risk: Oil will contaminate products, block filters, affect the equipment normal operation or even cause safety accidents.
3. Dusts
From: the dusts, rust particles and wear debris etc.
Risk: Dusts and particles will wear equipment parts, block pipeline and valves and affect product quality.
4. Microorganism
From: microorganism in the air including bacteria, mould and yeast etc.
Risk: microorganism will pollute the products, cause products deterioration or even result in health problems.
5. Harmful gas
From: sulfur dioxide, nitrogen oxides and hydrocarbons and other substances in the air.
Risk: harmful gases may corrode equipment, affect product quality and even endanger human health.
Compressed Air Treatment Ways
1. Condensation dehydration
By cooling down the compressed air temperature, water vapor will be condensed into liquid water and then be discharged. This method could be used to remove large quality of moisture. But it couldn’t remove oil and solid particles and its dew point is relatively high at around 3℃.
2. Adsorption dry
The adsorbent is used to adsorb moisture and water from compressed air and to lower air dew point. The pressure dew point could be lowered to -40℃ or below so it could be used for applications requiring relatively dry compressed air. However, it has a high energy consumption and operation cost and the adsorbent needs to be replaced regularly.
3. Oil & Dust Filtering
Filter materials are used to intercept and adsorb the oil drops and solid particles in the compressed air. Filters of different filtration accuracy are usually used together to remove particles and oil drops of different sizes. However, all the filter materials requires changing at fixed timely intervals with relatively high maintenance costs and their pressure drop is high, which might affect system pressure.
4. Activated Carbon Adsorption
Activated carbon is used to adsorb harmful gases in the compressed air. It has very high efficiency to remove harmful gases and is suitable for applications requiring extremely high compressed air quality. But the activated carbon shall be replaced at regular intervals with high costs and its adsorption capacity is quite limited.
5. Ultraviolet Sterilization
Ultraviolet light is used to kill microorganism in the compressed air. It has very high efficiency without any chemical agents and secondary pollutants. However, its cost is quite high and also it has requirements on air flow speed and lightening time.
Common Compressed Air Treatment Equipment
1. Refrigerated Air Dryer
Its function is to remove moisture or water from the compressed air and lower pressure dew point. It has the advantages of low energy consumption and low operation cost. However, its pressure dew point is relatively high, normally at around 3℃.
Refrigerated Air Dryer
2. Desiccant Air Dryer
It could further lower compressed air dew point to -40℃ or even below. But its energy consumption and operation cost are relatively high.
Heatless Purge Desiccant Air Dryer
3. Line Filter
Line filters are used to remove oil, and particles from compressed air. Its filtering materials need replacement at fixed time intervals.
4. Activated Carbon Filter
It is used to remove the unpleasant odors and harmful gases in the compressed air. It has very high efficiency to remove harmful gases but the activated carbon needs replacement regularly.
5. Ultraviolet sanitizer
It could kill microorganism in the compressed air with high efficiency and no secondary pollution. However, its cost is quite high.
Suggestions on Compressed Air Treatment Solution
1. Based on Applications
For general industrial applications, we can choose refrigerated air dryer plus line filters to remove moisture, oil and dusts.
For applications requiring relatively dry compressed air, we can choose desiccant air dryer plus line filters to further lower compressed air pressure dew point.
For applications requiring relatively clean compressed air, we can further choose activated carbon filter plus UV sanitizer to remove harmful gases and microorganism.
2. On Equipment Costs and Operation Costs
We can choose based on our budget because different equipment prices vary significantly and also we shall consider the energy consumption and maintenance fees etc.
3. On Equipment Reliability and Maintenance
We shall choose equipment with quality reliability and performance stability, and also easy maintenance and parts provision.
4. On Environmental Protection
Some countries may require environmentally friendly refrigerant for the air dryer. So we shall choose equipment in compliant with environment regulations to avoid causing environmental pollution. Moreover, equipment with low energy consumption and high efficiency shall be preferred.