Synthetic oil and Drain Frequency

Increasing drain intervals is one of the benifits of switching from a mineral oil to a synthetic, however, finding an optimum drain interval is best accomplished by also implementing a condition based monitoring program. If your current drain interval is now based on arbitrary time intervals how do you know that the oil you are replacing is spent. You might already have an opportunity to extend your drain intervals without switching to synthetic.

Using oil analysis you can determine if your oil has degraded or is just dirty. If you regularly change oil because it is dirty then switching to a synthetic will not increase your drain times as synthetic oils will get dirty also unless you address the comtamination issues.

Even for mineral oil 3-6 months sems like a very short drain interval. By effectively utilizing oil analysis, denying contamination access, and removing existing contamination thru the deployment of portable filters you may be able to increase your drain intervals dramaticly with the lubricants you are currently using.

That being said the improved oxidation resistance of synthetic oils over minera oils should give you at least a 3x improvement in oil life. However, you will never know without oil analysis.

As BuckHntr has said, oil analysis is one of the answers to your question. The other unasked question that I would have is if you are only getting 3-6 months from your lubricant are you using the correct grade and type in the first place.
Consider partnering with your lube suplier and have them perform a lube audit. They should check the equipment requirements vs what you are lubricating with. Assuming everything is correct then have them assist you in determining the optimal lube changeout interval. This means analysing samples from a statistical representitive amount of your equipment until a clear indicator is established to justify changing the oil. Then if the reason for change is oxidation etc then the extra cost of a group 4 synthetic would be justified.

regards......

Dear Joy

In order to increase your drain interval for the Rotating Machines, I think you should consider several actions, not only change to synthetic oils.

You could start by performing oil analysis, according to ASTM Normative, and in this way you could establish the real drain interval for each machine. Of course, if you put a better oil, you will extend the drain interval.

As second step, and with the oil analysis information, you could take actions in order to maintain the oil quality in your machines by external purification. If you maintain lower values of ISO 4406 (particles in the oil), and water content (lower than 100 ppm), the life of your oil is going to be longer.

As final action, you could think about a better oil. But, remember that you don't have only the option to change from Mineral Oil (Group I) to a synthetic oil(Group IV or V). This change represent a initial cost very big. (the ratio of the initial cost is 1 to 8). Remember you have the option to change to Hydrocracked Oils (Group II, Group III), with a lower initial cost than a synthetic oil (the ratio of the initial cost versus Mineral Oil is 1 to 2-3). Another issue is compatibility. When you make an oil change from Mineral Oil (Group I), to Synthetic Oil (Group IV or V), you have to have in mind the compatibility issues. Now, If you change to Hydrocracked Oils the compatibility isn't a problem.

If you need further information or support for the Oil Analysis Program, don´t hesitate to contact to us.

Best Regards,
Cristián Schmid
SICELUB

Everything that was said above is correct. My question is why were you changing the oil at 3 to 6 months? That is too short a time frame for the oil to be spent so I have to assume that it is becoming dirty. If this is the case than simply changing to synthetic oil is not going to solve your problems. Do you have breathers on your equipment to limit the input of contaminants? How are you adding oil in the first place - are you making sure it isn't contaminated as you are putting it in? Also are you adding a flushing agent before you drain the old oil to make sure that you get as many of the contaminants out as possible? Is the old oil still warm when you drain it so that it is holding the greatest amount of contaminants that it can?

Joy for draining oil in 3 months from rotating equipments may be due to low cost of oils in Kuwait or unavailabilty of good quality R & O oils. If rotating equpments that Joy meant here are turbines or Turbocompressors, Joy needs group III based R & O oils; I doubt if they are available in Kuwai with reasonable cost.

To change to group III or IV oils ( Synthetic), Joy needs to follow Mr. BuckHntr/Alan wallace advice.

Kumarkumartr2@yahoo.com

I assume, equipments meant by Mr. Joy is ring lubricated pumps, small turbines etc.

There are many possible solutions. Some are : providing good seals (labyrinth or hermatic type), good breathers, provision of oil mist lubricant, etc.

Oil mist lubrication will give fantastic results.

As quota from Bill Jacobyansky "Everything that was said above is correct.", but I would say maybe none of them can be applied to your situation.

Based on your description "DRAIN INTERVAL VARYING 3 MONTHS TO 6 MONTHS", I would assume not very much staff in you company know about the lubricants and lubrication. Also I would assume your plant does not have 100% output as designed capacity, maybe 60% or even less.

Basically, I would not suggest you to change from mineral to synthetic right away. But 3 MONTHS TO 6 MONTHS DRAIN INTERVAL, if it includes all big compressors/gearboxes/pumps, may cause unestimated loss for PETROCHEMICAL plant.

As rule of thumb, synthetic can last 4~8 times longer than minerial oil.

Before changing to synthetic, you should notice several things synthetic couldn’t do for you.

1. Always keep you lubrication system clean. This point cannot be emphasized any more. Lubricant to machine is like blood to human.

2. Always drain system completely. Check the lubrication system volume carefully to see if you drain correct amount of oil every time. For compressor, if you left 1/3 used oil in system and change mineral oil every 3 month, it may be acceptable. But if you extend the drain interval to 12 month and still have 1/3 used oil un changed, you may have trouble.

3. Select synthetic carefully. Some synthetic, like esters, may wash out the varnish in your system and jam the filter. If you don't notice it, the result could be disaster.

Personally, I have help several plants to upgrade to synthetic and see many fantastic and wired situation I cannot imagining. Synthetic is good, but it very much depends on the person who use it.

There is a tendancy for people who are having difficulties with mineral oil to want to switch to synthetics for immediate results. Sometimes this works but until a root cause for early failure can be determined the problem will never dissapear.
3 - 6 month oil drains is extremely excessive. As previously mentioned, oil analysis and other forms of condition monitering is always a good step to help rectify problems. There is nothing wrong with mineral oils. I only need to point to case studies like certain hydro electric plants in New Zealand that have been running the same oil since the installation of the equipment (approx 50 years). The oil is a standard 68 cSt mineral oil and to this day is crystal clear and running around 13/10. A well designed and maintained system may not benefit at all from the use of synthetics. I'm not trying to say that synthetics have no benefits because I can't speak highly enough of them. But in a situation like this it sound like the oil has no proper filtration and no condition monitering.
It is critical not only for the reduction of OCI's but machine life to get on top of problems like this.
My advice is the same as other members on this post. Start getting the oil and machinery tested to find out why the problem is occuring. An independant lube audit is an excellent way to start a program to reduce cost on both oil consumption and machine failures.