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“Lubricants don’t go bad; they simply get dirty.” This cliché has been shared widely throughout the industry despite being false. Lubricants fail through various mechanisms, including loss of additives and a change of molecular composition of the base oil; this is far more than simply getting dirty. While sayings like these may not be completely correct, the landscape is rapidly changing to where they may be more true than false.
Think about the advances in technology, especially in fighter jets. Each iteration of jet that comes out is more technologically advanced - to the point where a human pilot is less necessary. There will come a time where there is no longer a human inside the jet. The same advancement is happening with industrial lubricants. The question of when will be the last time we change oil in a machine should be considered.
Imagine a lubricant that never fails, never goes bad, and is perpetually operating at its optimum performance and chemical properties. The lubricant no longer needs to be changed; it is simply reconditioned to maintain its properties. This is the future of lubrication.
In the past, reconditioning of lubricants was mostly relegated to a series of decontamination steps for the removal of water and solid particles. The lubricant was cleaned and dried and then put back into service. This practice is still in use today, where the oil is drained from a reservoir into a tote or storage vessel, and a kidney loop system is employed to get the oil to a target cleanliness and dryness state. There is nothing wrong with this practice, but true reconditioning can go much further.
At the core of reconditioning, the overall goal is to get or keep the lubricant in a “like-new” state. This means the lubricant can perform to its original capabilities without any unanticipated hiccups; reaching this state will likely require more effort than simply cleaning the fluid. We have to concern ourselves with additive levels and base oil health when deciding if reconditioning makes sense. So, what parameters should a reconditioning program be measured on?
As with most programs, there would need to be a list of Key Performance Indicators (KPIs) to showcase that the program is responding the way we would intend. Below is a list of five potential KPIs that could be easily tracked for lubricant reconditioning.
Much like you would track these for an asset, you would want to be able to confirm that during any reconditioning process, an acceptable level of moisture and solid particulate is met. This is a good lagging indicator that your reconditioning tools (filtration, dehydrator, etc.) are working to the level they should. It is also a leading indicator for machine and lubricant health, as solids and moisture are catalytic particles leading to the breakdown of the lubricant and damage to machine surfaces.
A lubricant’s properties aren’t static; they change over time as the fluid ages and additive levels drop. Rather than simply monitoring additive levels or fluid properties such as viscosity and acid number, a good reconditioning program would look at the actual performance properties of the lubricant and how they compare to the original, “new” fluid. Simply refreshing an additive package or cleaning the lubricant doesn’t mean it will perform like new. Basic tests, such as filterability, demulsibility, air release and foam tendency/stability, offer great insight into whether the performance characteristics of the fluid are compromised or not. Depending on the type of fluid in question, you may add in tests that are more applicable to the in-service environment of the lubricant, such as FZG, 4-ball, etc.
As is the case for most programs, there has to be a financial reason to justify its existence. Reconditioning can provide savings in many ways, but one of the more immediate hard-cost savings should be in the purchasing of lubricant. However, it’s important to point out that not all fluids are suitable for reconditioning, which will be discussed later. The obvious goal is that the lubricant being reconditioned would show a drastic reduction in the purchase of that fluid type. This equates to an immediate cash savings that only grows as the fluid is maintained in optimum operating condition for a much longer period of time, perhaps indefinitely.
Longer life of the fluid means fewer oil changes and a longer period of time between these changes. This is a long-term metric but one that serves as the ultimate goal of the program, reducing (if not completely eliminating) the need to do an oil change. Start with a historical trend of time between oil changes or significant top-ups, and then set a goal of at least doubling that length of time. This will also help you gauge what necessary tools and modifications will need to be applied to your system.
There are many benefits to having an oil reconditioning program, but it may not always be feasible or economical to start this process. It does require effort, tools, expertise and the right application to maximize the effect. Much like previous articles that have mentioned the Optimum Reference State (ORS), this is no different. Some machines/lubricants will benefit, while others will not. Below are some factors to consider when determining whether a reconditioning program is right for your asset.
If the base oil is damaged, stop right now. Reconditioning likely won’t solve any issues and is just a band-aid until the oil can be changed. True reconditioning is a proactive measure that protects the structural integrity of the base oil molecules and the fluid’s properties. Waiting too long to start can stymie the efforts to begin with. If the base oil is still healthy, then other considerations exist.
Perhaps the most common variable when looking at any lubrication program advancement is the volume of lubricant the asset holds. The higher the volume and cost per gallon, the better care we should take of the fluid to get the maximum life out of it. For volumes less than 100 gallons, the investment might not make sense unless it can be further justified by criticality or the cost of doing an oil change.
When a system leaks fluid, new oil is put in to keep up the level at the appropriate volume. This new oil brings in new additives and serves as a way to refresh the oil in service. If you have a system that is prone to leakage and you are adding a significant volume of new oil each year, starting a leak mitigation program would be a higher priority than reconditioning. If top-ups are rare, then reconditioning can be further evaluated.
Availability of staff to perform oil changes is becoming a very real problem. As plants continue to operate on leaner staffing, extending oil life and minimizing oil changes begin to look very attractive. One would need to review how much labor is dedicated to oil changes or even available for these activities and estimate any potential savings related to this labor if a reconditioning program is initiated. This can help free up manpower for other initiatives in the plant as well.
Some oils will take to reconditioning better than others. Fluids that are heavily additized, like motor oils, do not make great candidates for this type of program. Conversely, low additized fluids, such as turbine oils, would be a great place to start. You would have to evaluate each fluid and determine the feasibility of maintaining an additive level. While it is possible for hydraulics and gear fluids to be reconditioned, you may find that it will not be economical depending on your volume of usage.
It’s exciting to think about how far this technology has come and is continuing to go. The benefits of lubricants lasting for a significant amount of time are tremendous, but it does raise some questions. What are the unintended consequences of extended oil life? There are bound to be some things that change within the oil that we are blind to or might not entirely understand. We do know that incredibly small particles build up inside the fluid and are never removed, as they are able to slip through filtration systems. As these particles build up, their surface area in contact with oil increases tremendously. This may lead to a change in the properties of the oil in ways that we haven’t seen in the past. Regardless, it is a great thought to ponder: when will be the last time you actually change your oil?