The Hidden Dangers of Topping Up Your Lube Oil

Synthetic lubricants were born out of a need for better lubricating properties, and the unavailability of crude oil in Germany. Aviation was the first application for synthetic lubricants, as they are superior to mineral oils at cold start up and cold climates. Synthetic oils have a higher Viscosity Index, offering better viscosity stability at varying temperatures. Group IV synthetic oils are man-made from PAO’s (polyalphaolefins) and Group V oils are made up of polyesters, phosphate esters, di-esters, alkylated benzenes and other synthetic molecules.

Another way of comparing the various refinement of oil is to compare the oil to a fluid with balls of varying sizes in suspension. The lower the Group level of oil, the greater variety of ball size and shapes (which represent the types of molecules). Group 1 oils will have millions of differing atomic compounds (molecules) making up the oil. As the oil is refined, the oil is more uniform and the ‘balls’ are the same size. Synthetic oils have only one size ball.
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The obvious answer is ‘No’, as there are other influencing factors that impact on equipment life such as start-up wear and vibration… but equipment life when oil is clean may surprise you.

Clean Oil Really Does Matter

When you order ‘new’ oil in to stock it typically has an ISO 4406 code of 21/18/16 NAS 10, which is very dirty for close tolerance rotating machinery.  Most OEM’s specify a cleanliness code of 16/14/12 NAS 5, which is substantially cleaner than new oil, but if you can reduce that cleanliness code to 15/12/10 NAS 4, you will extend the machinery life cycle by two and a half times.   So, if your rotating asset costs $10M with a service life of 20 years, you could expect a service life cycle of 50 years, so $10M for a 50 year service life is a prudent investment compared to $25M for the same service life.

ISO 20/18/16 NAS 10 as delivered 'new'!

ISO 15/12/10 NAS 4 - Post filtration, clean

                        

The British Hydraulics Research Association (BHRA) conducted a three year field study of a range of more than 100 rotational and hydraulic machines to ascertain equipment life and the results were compelling.
What the survey found was that breakdowns diminished and the life of equipment improved greatly the cleaner the oil was kept. Nearly 20 times longer… It proved that if you want to spend less in maintenance and downtime, simply keep your oil clean.

Case Study - Aluminium Smelter

A Queensland aluminium smelter which adopted a proactive condition monitoring program, has changed its hydraulic oil overhaul schedule from annually out to 7 years, by fitting desiccant breathers, servicing the oil with vacuum dehydration and fine filtration.  Traditionally, their gearboxes gave 10 years of service life, and now the gearboxes have a service life expectancy of 25 years.  Downtime and wear rates have been greatly reduced so they are confident about moving to a synthetic lubricant.  Synthetic lubricants do not tolerate moisture or particulate contamination as well as mineral oil but do improve your equipment life when kept clean.

There are many successful examples of this proactive condition monitoring, where operational and maintenance budgets have been greatly reduced and equipment capital budgets are halved.

Take Action with Your Lubricants 

You want to see thumbs up on your Lab reports...

There are many successful examples of this proactive condition monitoring, where operational and maintenance budgets have been greatly reduced and equipment capital budgets are halved.

Fact - Keep your in-service oil clean and dry and unscheduled downtime, failures, hot spots, wear, and breakdowns will reduce.

The Cost Benefit Analysis

As an added benefit, the expenditure for implementing proactive condition monitoring and lubrication filtration servicing is insignificant, compared to the savings in capital and operational up-time.  One unscheduled stoppage in a plant could pay for years of lubrication maintenance and service.
What are you wanting to see on your lab tests?

Summing Up

It may be naïve to suggest close tolerance machinery can last forever, but you can increase its service life cycle by multiples saving you money and maintenance headaches, all by simply keeping your lube oil clean.

So yes, your close tolerance machinery can nearly last forever, if your lube oil is well serviced.

If you would like further information on this article or others, please let me know or visit our website.

James McAllister
james@biokem.com.au
Ph 0466 625 225
www.biokem.com.au

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Why You Must Eradicate Contaminants from Your Lube Oil

Regardless of contaminant type, any lube system will be compromised if contaminated.  The effect can then compound as some contaminants have a catalyst effect, causing further problems.  The types of contaminants are quite varied including hard particles, soft particles, moisture and free water, gas and varnish.

Over the next few articles we will cover the range of issues that you should consider when managing your lubrication oil for close tolerance machines, hydraulics and gearboxes.

What you cannot see is doing the damage

Silica & Bright Metal at 100x
Let’s start with the types of contaminants:

1. Hard particles, such as Iron, Chrome and other metals, Silica and sand
2. Soft Particles, such as Copper, Tin and other soft metals, fibres
3. Soluble contaminants, varnish, incompatible top up lubes or additive packages
4. Gases and Aeration, process gases and aeration from ingression or inadequate system design
5. Water and liquid contaminants that can change lube viscosity

Hard particles will score and wear away lubricated surfaces, producing other contaminants in the lube oil, creating a snowball effect of increased wear rates. Wear particles and contaminants that oxidise, will deplete the antioxidants in additive packages, leading to varnish potential.

Soft contaminants have the potential to damage lubricated surfaces and increase wear rates, as well as depleting antioxidants, plugging filtration systems and galleries.

Varnish is a by-product of contaminants or depleted antioxidants, and a real concern in any lube system as the damage caused by varnish includes sticky and gummed valves and actuators, decreased tolerances which restricts lubrication to the wearing components causing higher operating temperatures.  Varnish can also plate out on bearing surfaces, causing hot spots and journal deformation. There are costs associated with varnish removal, but the real costs are downtime and loss of production.

Gas - In processing industries, where gas is present, such as gas compression facilities, lube oil can become entrained with gas, becoming aerated and not supplying the correct oil film or strength to the lubricated surfaces, as well as reacting with other contaminants in the oil to cause varnish potential. Aeration in hydraulic equipment also causes cavitation, prematurely wearing pumps, controls and work accessories.  Aeration and cavitation in lubricating oil destroys components and pumps, and reduces operating efficiency.

Moisture in oil is a common contaminant, as our climate can be humid with a wide temperature range.  In close tolerance rotational equipment, moisture levels below 200 ppm are acceptable but some OEM specifications allow for much higher.
                                                     
Free Water has a devastating effect on bearing surfaces, as the water droplet compresses and becomes super-heated into steam, exploding and 'etching' the bearing surface, rendering it unserviceable.

Magnified Samples (60x & 100x)

The following slides are all pictures taken by BioKem Oil Services in the last year.  They show a range of contaminants in 100ml samples of lube oil from gas compressors, turbines, steam feed pumps and gearbox lube oil tanks. For reference the black line shown is 44µm in width.

RUST – The presence of water speeds oxidation and additive breakdown of the oil and is considered a serious problem.  Particle size varies from 10 - 120 micron range

FIBRES - Typically introduced by improper cleaning and maintenance practices.

ASPHALTENES - particles are generally in the 0.5 - 2.0 µm range and they agglomerate into an oily sludge. This problem is made worse when free water is present.

SILICA & SAND – range of debris on this slide typically found airborne in Australia.

BRIGHT METAL PARTICLES - Typically comes from component wear. These particles are abrasive and, as a result, can lead to further wear and tear of the system bearings.

SOOT & SILT (<5µM), SILICA AND DUST PARTICLES - This is typically airborne contamination or part of sludge from the bottom of tanks.  Very hard and extremely abrasive against delicate components in boundary layer systems.

Non Magnified Samples

Sludge – This is a filter housing showing a buildup of oil additives after exposure to moisture (no magnification)

Varnish – Flakes of varnish plated out onto a filter and the varnish washed out onto an an absorbent towel (no magnification)

Examples of Damage

The next few articles will focus on how the different contaminants are caused, and the types of resolutions that can be performed.
If you would like further information on this article or others, please let me know or visit our website.

Clean Lube Oil Increases the Life of Rotational Equipment

Lubrication oil cleanliness is probably the single most important factor determining your rotational equipment longevity.

The British Hydromechanics Research Association (BHRA) conducted a three year controlled “field” study of 117 hydraulic machines.  The field trial was established with the sole purpose of correlating fluid cleanliness to breakdown frequency.  The results published are extremely compelling and worthwhile heeding.

You would assume that operating machinery within oil cleanliness specifications should assure that the life of the equipment is reasonable, R&M is fair and downtime minimised.  But what if the lube circuit oil is maintained at several levels of cleanliness above the norm?  The answer is surprising and the BHRA study shows that based on a datum of ISO 18/15 oil that oil that is two grades ‘cleaner’ will outperform the datum oil by 1.8x reliability based on breakdowns.  If the oil is running dirtier at ISO 22/19 then breakdowns are far more frequent and more than twice as problematic.

The chart also shows that the new ‘clean’ oil received from a supplier is typically ISO 21/18, and potentially harmful to your machinery if not polished before first use. 

If you suffer an event that compromises the cleanliness of your oil contact BioKem and seek advice as the oil can be recovered, dehydrated, filtered and polished so that it exceeds a new oil spec … a cheaper and possibly quicker solution than ordering new oil.

Research

In the 1990’s Nippon Steel implemented a hydraulic system contamination control program plant-wide, involving both improved filtration and rigorous fluid cleanliness monitoring, and pump replacement frequencies were reduced to one fifth and the cumulative frequency of all tribological failures (i.e., failures relating to wear and contamination) were reduced to one tenth.

Kawasaki Steel also implemented a similar oil contamination control program and almost achieved a 97% reduction in hydraulic component failures. Such claims as these spurred the British Hydromechanics Research Association (BHRA) and the U.S. Navy to conduct their own controlled studies to substantiate benefits of proactive contamination.

The BHRA study covered a three-year period and was based on the carefully monitored field experience of 117 hydraulic machines across various categories (i.e., injection moulding, machine tools, material handling, mobile/construction, marine, metal working, test stands, and miscellaneous). The results of the study showed a dramatic relationship between fluid contamination levels and service life.  Improved system cleanliness achieved extended actual mean time between failures (MTBF) from 10 to 50 times, depending on cleanliness.  A study by the Naval Air Development Centre in Warminster, Pennsylvania performed on aircraft hydraulic pumps showed nearly a 4-fold wear-life extension with a 66 percent improvement in filtration and a 13-fold wear-life extension with a 93 percent improvement in filtration. Solution

BioKem has the equipment to perform on-site oil purification to rectify post-event lubrication circuit contamination without discarding the oil and installation of conditioning vacuum dehydration equipment running kidney loop filtration.  BioKem can also presecribe and supply static solutions to resolve chronic oil cleanliness concerns.  Should you require a professional service to filter or HOF your circuitry, spools, coolers, lube tanks, manifolds then contact BioKem Oil Services.

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Hot Oil Flushing Methodology

What is Hot Oil Flushing?

Hot Oil Flushing (HOF) is designed to remove contaminants from the manufacturing process/transportation/site assembly, or a contamination event during operation, of a lube oil circuit, by flushing hot oil through the circuit at a minimum of 150% of its operational flow rate, achieving a minimum of Reynolds 4000 number, a unit of measure for turbulent flow. The theory being that contaminants such as pipe scale, welding slag and particles, are removed at 150% of operational flow and won’t contaminate the system at operational flow rate.

So what is the purpose of Hot Oil Flushing?

1. We HOF for several reasons,
2. New asset pre-commissioning,
3. Lubricant type change,
4. After a contamination event,
5. Scheduled maintenance

All OEM plant and equipment suppliers have their own methodology and specifications for pre-commissioning or hot oil flushing their assets.

Most conform to the two established standards ASTM D6439, and API 614.  The Standards require you to capture bulk particles on the return circuit via a screen or filtration, to prevent tank contamination, as you will require this oil to achieve a cleanliness specification prior to start up.

BioKem Oil Services works with both ASTM D6439 and API 614. Standards. WE believe it’s quite advantageous to capture all bulk particles and contaminants in the return circuit, to keep the lubricant within its ISO 4406 or NAS Class specification.

Also advantageous, is to apply fine filtration and vacuum dehydration, via kidney loop to the lube tank, not only are you removing contaminants and particles from the circuitry, but also purifying the oil to a minimum ISO 4406 code of 16/14/12 (NAS Class 6), and moisture content to below 200 ppm.

Service Oil or Base Flushing Oil?

Depending on the application, a service oil or a base oil similar to the final service oil can be used to flush the circuitry.  This decision is based on the availability of service oil, volume of oil needed for the flush, and the timings between flushing and equipment entering service.  In some circumstances the equipment circuits/spools may not enter service for some time afterwards and the final selection of service oil may not have been made or awarded.  In this circumstance a base oil can be used and then the pipework blown dry with compressed air and a purge of nitrogen or similar gas used.  If service oil is used then the HOF team will need to polish (fine filter) the oil ready for service.

Purging the system

If the circuitry can be sealed at the conclusion of the flushing then nitrogen (or other inert gas) can be used to stave off corrosion.  The methodology is to purge all oxygen from the circuits by venting the system whilst it is filled with inert gas.   Correct safety protocols should be followed as Nitrogen can be dangerous in confined spaces.

What Next?

Should you require a professional service to HOF your circuitry, spools, coolers, lube tanks, manifolds then contact BioKem Oil Services www.biokem.com.au

 

Copper Concentrator - SAG& Ball Mill Case Study

The Problem

Our client experienced a significant water and debris contamination event in theFixedBearing circuit of the SAG Mill.  The mill was immediately shut downto avoid bearing damage and the contaminated oil was removed and new then oil introduced.  Even so, there was concern that the circuits still had potentially harmful debris and moisture present. 

The lubricant removed was very dirty and saturated with water to 5000ppm, a level of contamination that high would normally mean disposal/total loss, at a cost of $20,000.

Lost production downtime at this mill is circa $1,000 per minute of downtime as the two mills run in series potentially affecting other operations.

BioKem’s mobile VDOPS, on site and operational within hours of arrival, and conforming to all site requirements.

 The Challenge

The rapid response solution was to firstly remove residual water and particulate contamination in the in-service SAG fixed bearing lube tank followed by cleaning and polishing of the bulk contaminated oil.  All tasks were completed in an urgent timeframe to mitigate any potential damage to the gearbox and trunnions.

Working with ISO 460 oil requiredraising the temperature from operating temp of 47°C to >70°C to lower the viscosity to a workable 100cSt or less.

Filtration was to be conducted on in-service oil by way of kidney bypass to the required standard in a reasonable timeframe.  Access restrictions added to the complexity of the job.

Solution

After initial contact and a phone consultation, BioKem mobilised the 50GPM Vacuum Dehydration Oil Purification System (VDOPS) asset and engineering team to the remote site in Queensland immediately.  Site inductions, JSEA and documentation were completed and BioKem were on site with all equipment within 30 hours.

The Mobile VDOPS is equipped with 2 x 32 kW heaters, capable of heating 100L/min of this gear oil to 80°C, and drawing over 20” Hg of vacuum, for the most efficient moisture dehydration and viscosity adjustments, without risk of damaging the oil further.

The VDOPS is capable of moisture removal and dissolved gases to below 50ppm, and ISO 4406 cleanliness to 13/12/10, with a β1000, 2.5 micron filtration.Equipped with 4m, 6m, and 12m hoses, we can access the most challenging locations. With 8 drain points and a pressurised flushing system, we ensure no cross contamination from previous jobs between different tanks and lubricants.

Fitted with 2” Camlocks, Plugs & Caps for quick installation and adhering to a ‘NO SPILL’ policy.

To keep downtime and revenue losses to a minimum, BioKem has developed operational procedures and reporting systems, that maximiseefficiency and professionalism, setting the industry standard.

In this case BioKem’s VDOPS not only purified the contaminated oil, but also polished other in-service oil whilst the asset was available, offsetting the cost of having BioKem onsite for the event and saving the customer money.

Purification Tasks

1.      SAG Mill Fixed Bearing Tank                                  6,000 L

2.      SAG Mill Floating Bearing Tank                              4,500 L

3.      Outside Bulk Tank                                                   5,000 L

4.      Polishing SAG Mill Floating Tank                           4,500 L

5.      Ball Mill Floating Bearing Tank                              4,500 L

       Total Oil Purification Completed                         24,500 L

1. SAG Mill Fixed Bearing Circuit Tank 6000L

Starting ISO:                            21/21/17 (out of spec)

After Purification ISO:     16/15/12

Water Content:               Not tested at start

Water Content after:      <50ppm

VDOPS Purifying Time:  26.9 Hrs

Comment: Client had sensibly drained the contaminated oil and deployed a small centrifuge that helped.  VDOPS further reduced the moisture and significant larger debris was captured as shown. 

2. SAG Mill Floating Bearing Circuit Tank 4500L

Comment:  Filtration was commenced on this oil however the oil did not respond normally.  It had a very dark appearance and smelled ‘burnt’.  A sample was taken and this oil displayed a ‘cake of fines’. 

Action:  Client was advised to go offline drain this tank as this contamination will cause significant wear.

A cake of fines is a very high concentration of silt size particles and/or additive pack ingredients that build up on the patch membrane obscuring all other contaminants.  If the additive package breaks down in this way and drops out of solution it is no longer performing its intended function.  The oil that was removed was dehydrated and left to be filtered over the next two weeks with depth filter media to remove these sub-micron contaminants.  Afterwards an additive pack will be needed to restore this oil.

3.     Outside Bulk Tank 5000L

Operating outside and beyond ISO 4406 spec

Starting ISO:                            23/22/17 (out of spec)

After Purification ISO:     21/17/15

Water Content:               5000ppm (out of spec!)

Water Content after:      100ppm

VDOPS Purifying Time:   20.3 Hrs

Comments: A huge 25L of water was removed and lubricant could then be returned to service.  The image shows the VDOPS collection chamber extracting water from the emulsified oil. No free water was present.

Summary

In total 24,500L of oil was purified to better than target specification in 114.2 Hrs.

The outcome was returning the plant to operation with a minimum of downtime and without discarding any lubricant resources and associated costs.  The client was so impressed with our response service and professionalism; they have requested a regular 90 day service agreement to manage the oil cleanliness.

Job#	Vol	ISO 4406 Start*	ISO 4406 Finish*	Hrs	Note
1  SAG Mill Fixed	6,000L	20.19.16	16.15.12	26.9	Excellent improvement in ISO4406
2  SAG Mill Floating	4,500L	-	-	33.5	Clean, however sub-micron ‘cake of fines’ still present
3  Bulk Tank	5,000L	23.22.17	20.19.16	20.3	Highly emulsified oil, 25L of water removed
4  SAG Mill Floating Polish	4,500L	20.19.16	-	12.3	Low level fines residue – visually OK
5  Ball Mill Floating	4,500L	23.22.17	Await result	21.2	Oil was dry, however anticipate significant improvement in cleanliness.
TOTAL	24,500L	-	-	114.2

Photo Essay

Comparison of SAG Floating oil contaminated with ‘cake of fines’ (Left) darker pigment compared to SAG Fixed in-service oil after VDOPS has cleaned it (Right).

Zero Spill Policy & Procedures

Advantage of pre-filtering the oil before the high value glass fibre filter is subjected to this level of contamination!

Graph of how the ISO 4406 cleanliness will saw tooth with the proposed deep filtration cycle over a rolling 90 days.  The redline is the upper allowable limit.

Redundant Technology was onsite, deemed unsuitable and mothballed