Use this side-by-side analysis to make an informed decision about whether to use mineral oils or synthetic lubricants in your compressed air system.

shutterstock_401009347Marketers of increasingly popular “oil-free” compressed air systems promise end-users low oil carryover and contaminant-free product air. However, much of the buzz around oil-free compressors is unfounded. In fact, oil-free compressors are not oil-free at all. Though they do not require it within the compression chamber, oil is needed to lubricate parts and to regulate the machine’s cooling process.

What’s more, atmospheric air usually contains between 0.05 and 0.5 ppm oil vapor — meaning that the complete elimination of oil in product air is nearly impossible. At the same time, oil-free compressors cannot eliminate air contamination resulting from water aerosols, rust, pipescale, atmospheric dirt, water vapor, or various microorganisms.

Traditional lubricated compressors offer the same level of filtration as oil-free compressors and, with the right systems in place, can meet air quality regulations across industries — including ISO 8573-1 Class 0 and Class 1 standards for applications requiring instrument air. As an added benefit, the up-front cost of a lubricated air compressor is between 45 and 50% lower than that of a comparable oil-free model. Traditional lubricated compressors also come with lower lifelong operational costs and enjoy greater durability, and low environmental impact thanks to filtration systems that mitigate condensate discharge.

Once end-users understand the quality, financial, and environmental benefits of investing in a traditional lubricated compressed air system rather than an oil-free compressor, they are faced with another question: What kind of lubricant should I use in my compressor? While air compressors have traditionally operated on non-detergent mineral oil, synthetic lubricants have gained increasing popularity in recent years.

Here are some of the benefits and drawbacks of each:

Traditional Non-Detergent Mineral Oils

Advantages:

  • Lower cost than most synthetic lubricants
  • Ideal for medium-duty use and home-users whose applications are non-industrial

Disadvantages:

  • Tend to overheat, requiring frequent oil changes
  • Not fire-resistant
  • Low energy efficiency
  • Include compounds of oxygen, nitrogen, and sulfur, which enables acid development, oxidation, and contributes to higher production of sludge — especially in high-temperature applications
  • Molecular irregularities that may create inconsistencies in surface lubrication, thus increasing friction between compressor parts

Synthetic Lubricants

Advantages:

  • Low flammability
  • Operate at lower temperatures, leading to fewer oil changes
  • High energy efficiency and usage per hour due to outstanding oxidative and thermal stability (for every 1,000 hours of use with a mineral oil, compressors can see upwards of 10,000 hours of use with a synthetic lubricant)
  • Strong molecular bonds that ensure consistent and reliable lubrication results
  • Predictably effective under varying environmental conditions (do not jellify in low temperatures or thin out in high temperatures)
  • Will not emulsify or create undesirable byproducts in humid conditions, due to their non-hydrophilic makeup

Disadvantages:

  • Higher up-front cost
  • Incompatible with some kinds of elastomers, plastics, adhesives, and coatings, if used when not recommended

The Clear Choice for Lubricated Compressors

While traditional mineral oils come at a lower initial price tag, only synthetic lubricants can guarantee the high energy efficiency, consistent performance, and long-term cost-effectiveness required by industrial operations. In particular, synthetic lubricants shine when it comes to high-load operations or working in highly variable environmental conditions or fire hazard zones. In general, manufacturers today recommend using either a 20 or 30 weight synthetic lubricant — rather than a mineral oil — to get the best results out of your industrial compressed air system. 

Regardless of industry, air compressor operators must comply with state and industry air quality regulations, which requires adequate filtration protocol. Learn about the advantages of our cutting-edge Mattei Absolute Zero (MAZ) filtration system to find out how to achieve oil-free instrument air with any compressor.

Topics: Compressor 101, Oil-Free, lubricant

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