Traditional Oil or Synthetic Lubricant - Which Is Better for My Air Compressor?

Oct 01, 2020

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If your company is one of the 70% of manufacturing facilities that use compressed air as a substantial portion of their operations, you know lubrication is essential for helping industrial air compressors maintain optimal performance and longevity. The choice of conventional or synthetic lubricant should be weighed carefully, though. In this guide, we’ll discuss some pros and cons of the two options to help you make an informed decision.

In this discussion, we’ll generally be talking about lubricated compressors. Oil-free air compressors do exist — they have no oil in the compression chamber and rely on Teflon-coated pistons, scrolls or screws for lubrication. They are beneficial because they reduce the risk of oil contamination, but when their protective coating breaks down, there’s no way to replace it. Many companies use lubricated compressors instead because of their lower upfront costs, lower operational costs, greater durability and longer life spans.

Traditional Oil Lubricants: Advantages and Disadvantages

Air compressors have long used oil lubricants to reduce internal friction, minimize heat damage and reduce wear and tear. Conventional lubricant in a compressor generally consists of mineral oil — often from petroleum — which coats the compressor components and helps them glide freely as they operate. Mineral oil contains some impurities, but it can be a reliable lubricant in many applications.

Air Compressor Advantages

The benefits of traditional oil in an air compressor mostly come from its cost-effectiveness and suitability for medium-duty use:

  • Cost: Traditional oil lubricant is generally more cost-effective than synthetic lubricant. In facilities where upfront expenses represent a concern, conventional oil lubricant may be the best choice.
  • Use patterns: Traditional oil lubricant is ideal for medium-duty use with lighter demands. It is also highly suitable for non-commercial applications where the compressor does not receive continual use.

Air Compressor Disadvantages

However, traditional lubricant comes with several disadvantages you’ll need to keep in mind:

  • Frequent oil changes: Conventional oil lubricant requires more frequent oil changes than synthetic lubricant because it tends to overheat and break down. More frequent oil changes also lead to higher maintenance costs and more downtime.
  • Low efficiency: Conventional oil lubricant offers minimal energy efficiency in comparison with synthetic lubricants. It has higher oxidative and thermal instability — the same factors that lead to breakdown and frequent changes — and gets fewer hours of use per application of lubricant.
  • Minimal fire resistance: Oil lubricant will offer no fire resistance in your compressor — and in some cases, it may be flammable. Facilities that deal with fire hazards will likely want to avoid traditional oil lubricant for this reason.
  • Sludge production: Oil lubricant produces more sludge than its synthetic counterparts. Conventional oil lubricant often contains compounds made of oxygen, nitrogen and sulfur — all of which promote acidification, oxidation and sludge production, especially at high temperatures. Sludge can reduce the compressor’s efficiency and is challenging to remove.
  • Possibility of friction: Traditional oil lubricant can occasionally allow for friction between compressor parts. This friction may occur when the oil degrades and elements of the broken-down fluid harden on the compressor components.

Synthetic Lubricant: Advantages and Disadvantages

Synthetic lubricant provides an appealing alternative to conventional mineral oil lubricant by minimizing many of its disadvantages. Synthetic oil comes from raw materials that have undergone cleansing, stripping and filtering until they consist of only their essential molecules. Because of this refining process, they do not contain the impurities typically found in conventional oil lubricant.

Air Compressor Advantages

Synthetic lubricants offer many benefits for air compressors, including:

  • Low flammability: Because of their chemical modifications, synthetic lubricants are minimally flammable. Especially in facilities where fire danger is a concern, the fire-resistant properties of synthetic lubricants offer valuable peace of mind.
  • Fewer oil changes: Because synthetic lubricants last longer and require fewer changes than traditional oil lubricants, they are often more convenient. They reduce maintenance time and costs and keep operations running smoothly.
  • Energy efficiency: Using synthetic lubricants helps make your air compressor more energy efficient. You’ll get more use out of each application of lubricant and generate less waste.
  • Superior performance in extreme conditions: When traditional oil lubricant experiences excessive humidity, it sometimes degrades and emulsifies or produces undesirable byproducts. Synthetic lubricants hold up well in high humidity and will not cause these challenges.
  • Lengthened air compressor life expectancy: Using synthetic lubricants instead of oil lubricant helps extend an air compressor’s life span. Because it doesn’t degrade like conventional oil and protects better against wear and tear, synthetic lubricant is easier on the compressor’s internal systems.
  • Increased usage per volume: Imagine using the standard amount of traditional oil lubricant in one air compressor and the same amount of synthetic lubricant in another. The oil lubricant will be the first to degrade, and when it does, the synthetic lubricant will still be going strong. Companies can get more use out of synthetic lubricants, so they can benefit from purchasing less of it and generating less waste.

Air Compressor Disadvantages

The main disadvantages of synthetic lubricant in an air compressor involve its price and a few usage limitations:

  • Higher cost: Synthetic lubricants tend to cost more than their conventional oil counterpart. For companies where budget restrictions are tight, oil lubricant may be a better option. However, because synthetic lubricant requires less-frequent changing, compressors use less of it, so facilities can spread out the expense more over time to diminish the cost difference.
  • Limitations on use: In some applications, synthetic lubricants are not ideal. Particularly with plastics, elastomers, adhesives and coatings, facilities will likely want to use oil lubricant in their compressors instead.

Knowing When to Avoid Synthetic Lubricant

Given the pros and cons above, it might seem that synthetic lubricant is the superior choice except in a few specific applications. In some scenarios, though, it’s best to minimize the use of synthetic lubricants in your oil compressor. To determine when to avoid synthetic lubricant, you’ll need to know the properties of your machine and what impurities it contains.

Machine impurities, like acid gas in some machines, can cause fluid failure. Impurities can also build up in the lubricant and cause corrosion in a compressor. If you suspect impurities in your machine, you’ll likely want to stick to traditional oil lubricant.

Contact Fluid-Aire Dynamics for All Your Air Compressor Needs

To gain the benefits of professional expertise and a wealth of industry knowledge, trust Fluid-Aire Dynamics for compressed air solutions. We offer a full range of services, including system monitoring, preventative maintenance, service and repairs, complete system design and fabrication and installation. We can provide reciprocating compressors, rotary-screw compressors and pressure-lubricated compressors for a variety of applications.

Be sure to take advantage of Fluid-Aire Dynamics’s compressed air system review. With this comprehensive system review, we can provide extensive data about your compressed air system and develop a tailored plan to reduce costs, boost efficiency and enhance your system’s performance.

Contact us today to learn more.

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