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In order to fully understand the correct approach to industrial oil reclamation and the consequences of doing it incorrectly, one must first acknowledge that industrial oils are formulations. This means several additives have been blended in a base oil to enhance its naturally occurring lubrication characteristics to satisfy the specific requirements of a given application.
It is often asked of formulated lubricants: What is the normal life expectancy of a lubricant? or Will any of these fluids last indefinitely? To answer these questions, one must know the following:
the severity of the application
maintenance practices of the fluid user
operating load and temperature
fluid handling practices of the user
the equipment design
the potential for ingressed contamination
user’s attitude and knowledge concerning contamination control
the quality of the fluid
any other information that will directly impact the fluid
For example, placing a fluid in a severe hydraulic application is possible, but it only takes a matter of days or even hours before it is destroyed (Figure 1). This occurs because of an equipment design problem or a misapplication of fluids. However, it is not unusual for some turbine lubricants in a system to perform satisfactorily for 30 years or longer.
Just as the human body ages daily, lubricants also steadily degrade toward oxidation. The life expectancy of oil will decrease with abuse. The slope of the oxidation curve is determined by the original oil formulation, the severity of the application and the contamination control and fluid handling practices of the user. The latter may be the most significant.
Oil Recycling and Reclamation
It is important to differentiate between reclamation and recycling.
Recycling: the act of returning something or a part of something back to useful service, perhaps different from the original application. In this context, recycled oil can be put back in service as a formulation differing from the original, and/or possibly in an application with less stringent lubrication requirements.
For example, heavily oxidized oil, admixed formulations and some chemically contaminated oils cannot economically be reclaimed. However, they can be recycled and rendered useful again for the same application by re-refining them, stripping out all additives and re-additizing them (Figure 2). Re-refining is not a simple process nor is it as economical as reclamation.
Heavily oxidized oils, or spent oils, can also be blended and used as bunker fuel for ships. Normally, they cannot economically be fractionated, re-blended and placed back into service for which they were originally formulated. Recycling oils is a good practice; however, with a little planning, some oils can be reclaimed before they reach the point at which recycling is the only option.
Because recycling information is widely available, the remainder of this paper will address the process of reclamation only.
Reclamation: the act of salvaging, recovering or reclaiming. In this context, the oil is rescued from a normal degradation toward disposal. This rescue should be conducted onsite. If the oil is removed from the premises and reclaimed at a remote location, the potential for cross-contamination increases tremendously. Also, if an oil spill or accident occurs during transport, the owner of the oil is liable.
For example, dirty, wet oil with a low additive content may be a candidate for reclamation because the dirt and water can be removed. With some guidance from the oil formulators, the additive package may be refortified. The oil can then be placed back into the same service for which it was originally formulated, in a condition suitable for continued service (Figure 3). In most cases, performance analysis on reclaimed oils is recommended to confirm “like new” or “fit for service” condition.
Recognizing A Reclamation Candidate
Reclaiming industrial lubricants can be advantageous for everyone. The fluid manufacturer and the fluid user must cooperate, and be able to answer the following questions:
What constitutes a viable reclamation
If I choose to reclaim, how will I know that
the oil has been successfully reclaimed?
Answering the following questions can help determine if an onsite oil reclamation situation exists:
1. Can the leaked or spilled oil be collected and contained?
2. Is there sufficient fluid volume to create an advantageous reclamation situation? (Rule of thumb is 2,000 gallons. This number could be lower depending on the original cost of fluid, ease of reclamation, proximity and availability of reclamation equipment.)
3. Has any other liquid contaminant (other than water) or chemical been mixed with this candidate oil?
If the answer to questions one and two are yes, and the answer to question three is no, then a sample should be submitted for testing.
In some cases, liquid contaminants other than water can be removed. Contact the fluid manufacturers for specific questions.
The sample should be tested for the following:
Sediment by centrifuge
Viscosity, cSt at 40ºC (D445)
AN, mg KOH/g (D664, et. al.)
RPVOT, minutes, (D2272)
Water Separation at 130ºF (D1401)
Trace Metals Analysis, ppm (D5185)
The test results should be discussed with the fluid manufacturer to see if further testing is required.
Once the fluid is determined reclaimable, a suitable onsite reclaimer should be contacted.
Beware of reclaimers who make the following statements:
Some oils cannot be reclaimed, and some should not be reclaimed for economic reasons. Additive formulations are often proprietary, or the additives are not easily purchased. There is also the question of whether the reclaimer can finance the liability of equipment damage, downtime and/or bodily harm. The brand of the original oil does not matter. If the oil is reclaimed, it becomes the reclaimer’s oil and he is responsible for its quality and performance from that day forward.
In the normal course of events, all industrial oils are on a naturally occurring degradation curve. If the oil stays in the system long enough, it will oxidize and simple reclamation may not be a viable option. However, if during its normal life, the oil spills or leaks and mixes with dirt and water, it may still be salvageable. If the oil becomes extremely contaminated with particulate even while still in the system, it may be salvageable. However, if the oil blends with incompatible oils and/or chemicals while in the system, on the floor or in the containment area, recycling may be a better choice than reclaiming.
A representative sample of the oil considered for reclamation should be sent to a laboratory for testing it against its original performance specifications. “Representative” is used because the statement “garbage in, garbage out” still applies. The test results reflect the sample that was submitted. Therefore, it must accurately represent the fluid considered for reclamation.
Typically Reclaimable Oils
These are typical candidates for reclamation:
1. hydraulic oil
2. turbine oil
3. circulating oils for bearing lubrication
4. paper machine oil
5. gear oil
6. quench oil
7. some metalworking fluids
8. transformer oils
9. some synthetics
10. several specialty fluids
Cross-contaminating these oils can be hazardous. Improper reclamation presents potentially heavy liability. The effects of this type of contamination are subtle and may not show up until years later.
Additives are designed to function in a particular way, under certain conditions in a particular application. However, if different lubricants and additives are blended, they may function in an unpredictable way. Some of the additives function by attaching themselves to metal surfaces. Once introduced to a system (including reclamation equipment), these additives can be difficult to remove. That is why knowledge of the proprietary additives and involvement of the formulators are important to successful reclaiming.
Selecting A Vendor
There are many reputable reclamation companies in operation today. To determine a company’s credibility, ask these simple questions:
1. Do you test the oil before reclaiming it?
2. Do you test the oil after reclaiming it?
3. Can you supply particle count data at the site during the reclamation job?
4. Is there a cost savings associated with reclamation?
5. Can you legally and accurately refortify the oil onsite?
6. Are the original formulators involved?
Under the right circumstances, reclamation is a suitable option that can financially benefit both the reclaimer and the user of the oil. Reclaiming reduces both the amount of oil sent for disposal and the cost associated with disposal.
Today, it is unnecessary to allow these fluids to deteriorate to an extremely contaminated, detrimental condition. If they do, however, many of them can be reclaimed and returned to a condition suitable for continued use. This practice has a positive environmental impact andeconomic significance for both oil manufacturers and oil users.