Peter Dufresne Jr.

Executive Vice President, EPT

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We are pleased to share with you our fourth newsletter that offers a fresh perspective on technical issues facing the industry.

In this issue we present the second in a three-part Straight Talk on Varnish series that answers questions users face when determining how to address lubricant varnish issues and prevention. We also present some options to consider adding to your lubricant maintenance “toolbox” that will make tangible improvements as you move into planning for next year.

Thank you for your interest.


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Current Newsletter Topics:

  1. Straight Talk on Varnish – Part 2
  2. Update Your Maintenance Toolbox to Set Yourself Up For Success Next Year
  3. Training Courses


Register now to read our Varnish White Paper.


Part 2: Do Group II oils deserve their bad reputation?

Users often complain that before using Group II base-stock oils, they didn’t have a problem with varnish. As a result, Group II oils have a reputation for being varnish prone, leading users to search for alternatives. The market has responded, with many companies offering low-varnish versions, co-base stock oils, synthetic oils or even after-market additives for the more adventurous.

The truth is, Group II oils do have less capacity to hold breakdown products in solution than Group I. This is because breakdown products are polar in nature and on the spectrum of polarity, Group II base stocks are less polar (more non-polar) than Group I base stocks. Therefore, because “like dissolves like,” polar breakdown products are more likely to precipitate out of solution from more non-polar Group II oils than Group I resulting in varnish deposits.

To understand how these oils breakdown over time, we ran thermo-oxidative breakdown experiments in the lab subjecting each oil sample to peak turbine operating temperature (150°C), air and a copper catalyst. The results presented include acid number, RULER amine and phenol antioxidants, and MPC varnish potential (Fig. 1).

In the Group I sample, we see a rapid increase in varnish potential achieving a critical value in <5 hours. Acid number remains stable until approximately 80 hours when a rapid increase is observed corresponding with depletion of the amine anti-oxidants. While a Group I user may not change this oil because of MPC value, they would be forced to because of the significant increase in acid number. In the Group II sample, varnish potential values increase gradually, not hitting a critical value until 400 hours. Strikingly, we see no increase in acid number with amine life extended to 700 hours – 10x that of the Group I sample.

Overall, we see a Group I base-stock oil that is sensitive to oxidation that quickly reaches critical varnish potential values and a Group II oil extremely resistant to oxidation with no acid production over the life of the test, even after the antioxidants are consumed. While some users may discount this lubricant because of the varnish potential numbers observed, in actuality the performance is exceptional. Considering that resin-based varnish removal systems are very effective, the perceived limitations of Group II oils are misunderstood.

In Part 3 of this series we’ll discuss polyalkylene glycols (PAGs) and how they compare to Group I and II oils.

Register now to read our Varnish White Paper.


Start the ACE™ Assessment.


Each year, turbine users find themselves with some left over budget money for the year to allocate. Below are three options to consider adding to your lubricant maintenance toolbox that will leverage these funds and set your maintenance program up for success next year.

1. Update Your Varnish Removal Program

Out-of-date or non-performing varnish removal systems can be a black eye on lubricant maintenance programs. Consider replacing this equipment with updated technology that will eliminate the issue permanently. Replacing maintenance-heavy systems with easy-to-maintain systems that only require annual filter changes will save time and leverage maintenance budgets going forward.

As an example, EPT’s soluble varnish removal (SVR™) system removes existing varnish deposits, but more importantly eliminates the root cause of varnish. These systems typically require two sets of consumables in the first year and one set thereafter. They also require little maintenance and can be procured on a rent-to-own basis or purchased. With the average large industrial gas turbine having one failure per year as a result of varnish, the return on investment (ROI) of an SVR™ system is up to 500% with a payback of less than 1 year.

2. Give Your Oil Reservoir a Nitrogen Blanket

The most harmful contaminant in your oil system is water. Atmospheric water ingression is the most common pathway in any oil system that is vented to atmosphere. While breather elements do a partial job, they have a very limited capacity so require frequent replacement making them maintenance heavy and expensive.

Free flowing nitrogen blankets, such as the EPT total moisture removal (TMR™) N2 system, provide unlimited capacity to remove water and eliminate atmospheric water ingression. They will actually regenerate the existing breather elements, reducing maintenance costs. These systems are small nitrogen generators that have no moving parts or expensive consumables and require no electricity. Compared to conventional systems, such as vacuum dehydrators, TMR™ N2 systems can provide an ROI of up to 900% with a payback of 2 months.

3. Purchase Prepaid Oil Analysis

Many commercial oil analysis labs offer prepaid test kits. These are a great way to leverage left over budget money to set up next year’s maintenance program. While EPT includes 3 months of complimentary performance testing with each maintenance system purchased, most customers continue to rely on our expert review. EPT’s analysis and comprehensive evaluation (ACE™) assessment kits can be purchased on a prepaid basis and shipped to your site for future use.

For more information please email [email protected].


    Next Course Dates:
    Sept 15, 2016
    Nov 24, 2016

    For more information please view our training brochure.

    To register please contact Barbara Creighton at
    or email.


    Looking to understand best practices in lubricant management in a vendor-neutral environment? Join us for the second and third installments in a 3-course series dedicated to providing you with the practical knowledge you need to optimize your lubrication management.

    Sept 15: Lubrication Selection and Problem Solving – Advanced Content.

    Nov 24: Oil Analysis and Report Interpretation

    Modern production equipment requires sophisticated lubrication management to ensure reliable, safe, and efficient operation. This series of three, one-day, vendor-neutral training classes offered by LubeWorks and EPT will provide expert training on current best practices in lubricant management applicable to a wide range of industrial lubricant applications.

    These courses are targeted for Reliability Engineers, Maintenance Personnel, Operators and Technicians that work with lubricating oils on a regular basis. Knowing how to implement or improve a lubricant management program is critical to the success of your operation. This specialized training offers an ideal opportunity for lubricant users to increase their knowledge and skills so they can perform their responsibilities with a higher level of understanding and expertise.

    Please view our training brochure for details on what you will learn in these installments of the series.