The Oil Analysis Paradigm Shift Using Fine Filtration Systems for Landfill Gas
The Paradigm Shift
When working with a new customer and using a refined filter, Trinity recommends using two independent labs for oil sampling during any performance program. Comparing results from the two labs helps identify and address odd or inconsistent readings, which can happen with oil sample testing. In addition, by comparing the sample results over time, we could better assess how the Trinity products perform and assist in extending the life of the oil and equipment.
Throughout a performance period, the sampling should attempt to look at both results between labs: however, each lab could have different "flagged" or “condemning” criteria for contaminant levels according to the customer, manufacturer, engine, or equipment types. For example, looking at Iron (Fe), one lab flags "critical" at over 250 ppm, whereas another lab flags it at greater than 20 ppm (critical). Several labs use oil sample "flag criteria," which are manufacturer recommendations and can present a significant disparity between them. Which one is correct? The answer is that they both can be, depending on customer requirements. However, to help clarify and mitigate this variation, Trinity brings in tests such as particle count (ISO 4406), Karle Fischer (water), and ferrography, which visually confirm ferrous wear metal concentrations and size.
Size Matters
The rationale for conducting these additional tests is to bring in other supporting criteria that can clarify and put into better context condemning factors. For example, even though you may have high Silicon or Iron concentration (ppm), it does not reflect the size of the particles (particles per milliliter) that a particle count (ISO 4006) test would identify. It is the size we look to concerning engine wear. Most engine-wear contaminant sizes occur between 4-10 microns or well below the size full-flow filters are designed to handle. According to Reliability Technologies, "tests indicate that fine, hard airborne environmental contaminants ranging in size from 2 to 20 μm cause 80 to 90 percent of abnormal wear in oil and grease-lubricated machinery."1
Particles in the oil film moving within the clearances between the moving parts are called Clearance-Sized Particles or CSPs (refer to Fig. 1). For an engine like a Caterpillar 3516 or 3520, the average film thickness is around 3-5 microns between the piston rings and cylinder walls depending on compression and temperatures. A particle (or dust) small enough to work within the film thickness is a non-wear issue. In contrast, particle sizes large enough to wedge themselves within the film thickness but slightly more prominent (i.e., 4-10 microns) create the most abrasive wear. According to a Society of Automotive Engineers (SAE) International article," Correlating Lube Oil Filtration Efficiencies With Engine Wear, “The researchers found clearances in the Diesel and Gasoline Engines varied between 2 and 22 Microns during engine operations. That means particles in the 2 to 22 Micron size range will most likely damage engine parts.”2
Fig. 1 Clearance-Sized Particles (CSP)
Why Do We Care About Film Thickness
According to Lubrication Explained, the “film thickness” is “two loaded surfaces being supported by a film of lubricant” (refer to Fig. 2). The size or distance between the moving parts where the lubricant resides is determined by “taking two mean datums of the two moving surfaces and determining the distance between them (refer to figure 1.). Therefore, a contaminant larger than the film thickness that works its way between the moving parts and more prominent than the film thickness, in this case for diesel engines, is 3-5 microns between the piston and the cylinder wall, causing the most significant damage or wear. Any particles that make their way into lubricating and hydraulic oils typically break down until they reach the working clearances of the machinery, where they can do the most damage. For instance, a single 10–30-micron particle, which is slightly smaller than can be detected by the naked eye, may break down into hundreds, even thousands, of 5-micron or smaller particles, with a consequent eight-fold increase in destructive potential. Even 500-hour oil serving, these damaging particles are already wreaking havoc on the engine. Additionally, smaller particles remain suspended in the oil column for extended periods, attracting more water and using more of the oil's additive package to neutralize their oxidative effects. In spectrograph, WM's primary method of examining oil samples measures the particle concentration of wear metals less than 3-5 microns. This is considered a lag indicator as it measures damage that has already occurred from more significant wear metals greater than 5 microns already ground down into finer particles between the moving parts and getting past the piston seals into the crankcase oil. High acid levels can also contribute to a spectrograph reading by the acids atomizing wear metals to a tiny size (i.e., <1 micron), and why large concentrations can appear in oil samples results but may not necessarily be an engine-wear factor. To protect against these, “we need to increase the viscosity of the lubricant being used or filter down to a lower level.”3 Trinity’s ability to filter down to 1 micron removes these damaging particles making them a non-wear issue. For example, through a spectrograph analysis, you could get a critical level reading for Iron (Fe) of 30 ppm based on engine manufacturer criteria and “in-line “oil filter systems. However, if only using these full-flow filters that can remove contaminants, at best, down to 10 microns and measuring contaminants less than 5 microns, you can see that there is no reading for the most damaging contaminant between 4-10 microns. In this case, since these are not being removed or measured, it would behoove the equipment operator to use more conservative criteria since they are roaming in the dark. To fix this, we can go back to the quote from Lubrication Explained, “we need to increase the viscosity of the lubricant being used or filter down to a lower level.” Therefore, Trinity bypass filtering systems removing contaminants down to 1 micron require additional tests such as particle counts (ISO4406), Wear Index readings (wear particle concentration for large particles>5 microns and small particles < 5 microns), and ferrography (visual) is a must to determine when to change your oil. Relying only on spectrograph analysis and using in-line filters keeps the equipment operator in the dark about when to change the oil, along with poor filtering performance causing unnecessary and expensive oil changes. Using Trinity's continuous cleaning method and removing the water ensures the oil remains better than new for extended periods, repeatedly keeping your lubrication in top condition.
Fig. 2 Film Thickness and Linear Wear vs. Micron Size
Landfill to Gas (LFG) Challenges
Many contaminant issues in LFG operations involve methane gas and its composition (refer to Fig. 3). Some of the compounds in landfill gas, like siloxanes, chlorides, and H2S, can form byproducts that harm an engine (e.g., silicon, silica, and acids). If left unattended, they will become an engine wear issue, assuming using only full-flow filters as the primary filtering method. Trinity products keep the contaminants well below the 4-10 harmful particle size levels and within the piston and the cylinder walls film thickness of 3-5 microns and remove the water, a catalyst for acids. As such, particle concentrations set by engine manufacturers are less critical a driving factor for oil changes than the particle count, which measures concentrations of particle size. In addition, by removing the water, we lessen oxidation, sulfation, and nitration, reducing the catalysts for acid and corrosion. The damaging silicon is likely siloxanes from biodegradable commercial waste products, capped covers that seal the landfills containing sand, or environmental dirt. The good news is that the particulate concentrations become a moot point since the wear elements are managed down to 1 micron or well below the 10 microns or the most damaging sizes. Also, Trinity conditioners assist with better combustion efficiency reducing detonation events that can saturate and contaminate the oil.
Finer filtering of high-valued or high-precision machinery, like the LFG generator engines, should use bypass filters. Trinity products set a much higher oil life bar, allowing for broader parameters that signal you to change your oil due to the vastly improved performance of Trinity filters over full- flow filters. As a result, Trinity products will enable you to extend the oil's life, reduce oil disposal and consumption, and ultimately extend the equipment's life, reducing the overall cost.
The Trinity Advantage
Trinity products present a fundamental shift in oil filtering for a few reasons. First, the Trinity patented filters remove contaminants down to 1 micron (99.3% filtering efficiency based on independent lab results) and nearly all the water (on average below 200ppm). In addition, we've integrated magnets into the filters (unique in the industry), enhancing the filtering effect by pulling out more extensive ferrous materials allowing for better water absorption and adsorption of smaller particulates on the filtering material. Also, we apply fuel conditioners to the fuel lines providing better combustion efficiency, decreasing combustion events, and reducing particles that can blow past the piston seals into the crankcase oil while reducing harmful emissions.
The result of this unique combination of fine filtering and fuel conditioning changes the way you maintain your equipment. Most lubrication industries use full-flow filters, limiting the ability to clean the oil and forcing frequent and unnecessary oil changes. It is a culture of routinely changing your oil, but it does not have to be that way. Applying a better, more refined way to filter oil and complimenting it with a fuel conditioner provides a much cleaner and longer-lasting oil. The result is a paradigm shift in analyzing the oil and the parameters that signal you to change the oil.
1 https://www.machinerylubrication.com/Read/987/it' s-all-about-size
2 https://gavarino.com/correlating-lube-oil-filtration-efficiencies-with-engine-wear/
3 https://www.google.com/search?q=what+is+the+defintion+of+oil+fim+thickness&source=lmns&bih=797&biw=1270&hl=en&sa=X&ved=2ahU
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