How to Get Clean, Dry, Oil-free Compressed Air From Any Compressor

Submitted by Mark White - Compressed Air Treatment Applications Manager, Parker Hannifin
In this white paper, Mark White, Compressed Air Treatment Applications Manager at Parker Hannifin, explains the differences between oil lubricated and oil-free compressor technologies, the contamination risks associated with each, and how to mitigate those risks by installing the correct purification equipment required to deliver clean, dry, “Technically Oil-free Compressed Air”.

In today’s modern production facilities, the use of compressed air is often pivotal to manufacturing processes. Irrespective of whether the compressed air comes into direct contact with the product or is used to automate a process, provide motive power, package products, or even to generate other gases on-site, a clean, dry, reliable compressed air supply is essential to maintain efficient and cost-effective production.

There are many different types of air compressors available today, and due to its efficiency and reliability, the rotary screw compressor has firmly established itself as the technology of choice for many industries and applications.

Choosing a rotary screw compressor can be a daunting task due to the number of manufacturers and the many variants they provide. One of the biggest decisions to make when selecting a screw compressor is whether to select an oil lubricated or oil-free model.

Marketing messages are often aimed specifically at industries such as food, beverage, pharmaceutical, and electronics, and play on the fear that oil is the biggest contamination threat they face from compressed air.

Unfortunately in the pursuit of oil-free compressed air, the downstream air treatment system is often neglected or overlooked completely. For this reason, many users are disappointed to find that oil contamination and water are still present after the installation of their new compressor.

This paper has been developed to provide the reader with an understanding of where oil and other contaminants originate in a compressed air system and how to achieve clean, dry, oil-free compressed air for critical applications.

Where does oil come from in a compressed air system?

The oil found in a compressed air system will enter from two main sources:
  • Contamination Source 1 - the ambient air (oil vapor)
  • Contamination Source 2 - the air compressor (liquid oil/oil aerosols/oil vapor)

Left untreated, oil in one or more of the 3 phases will contaminate the air receiver and distribution piping. It can therefore be said that indirectly, the air receiver and piping are additional sources of oil contamination (3 and 4).
  • Source 3 – The Air Receiver
  • Source 4 – The Distribution Piping
Figure 1

Contamination Source 1 - The Ambient Air

Ambient air contains oil in a gaseous form (oil vapor). The oil vapor in ambient air is actually a combination of hydrocarbons and VOC (Volatile Organic Compounds) which come from natural sources as well as from vehicle exhausts and inefficient industrial processes.

Primary Pollutants

How much “Oil Vapor” is in the ambient air?

Typical values quoted for oil vapor contamination state that 1 cubic meter of ambient air typically contains between 0.05mg/m³ and 0.5mg/m³ of oil vapor.

This however can be higher in dense, urban or industrial environments or next to car parks and busy roadways.

Oil vapor levels are dificcult to measure as there is no single “oil” in air test available (at least not a very accurate one). Therefore for accuracy, one must test the ambient air for the different compounds and combine the test results.

Global targets to improve air quality has led to many air quality sample stations being set up. These typically test for the compounds which are more harmful to human health (NOX, SOX, CO, CO2 and Ozone). A number of these facilities also test for additional compounds, especially the VOC. We can therefore use this data to verify the presence of “Oil Vapor” in the ambient air.

Click on the link below to read the full white paper.

How to Get Clean, Dry, Oil-free Compressed Air From Any Compressor

Compressed air contamination problems can be simply avoided by installing a Parker OFAS HL Oil Free Air System fitted (including OIL-X filtration).  Learn more about this system below. 

Parker OFAS Oil Free Air System

Advanced Solutions | OFAS Oil Free Air System

Parker recently introduced a new compressed air purification system. The OFAS Oil Free Air System is a fully integrated heatless compressed air dryer and filtration package suitable for use with any compressor type and can be installed in the compressor room or at the point of use. Fitted with a third adsorbent column for oil vapor removal, the OFAS has been third-party validated by Lloyds register to provide ISO 8573-1 Class 0, with respect to total oil from both oil-lubricated and oil-free compressors, ensuring the highest quality air at the point of use for critical applications.

Have questions?  Call us today at (855) 737-4717 and ask to speak to one of our filtration specialists.