#VartechTechnology

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VARTECH TECHNOLOGY:  AN UNBELIEVABLY EASY METHOD THAT WORKS FOR YOUR GAS TURBINE

To understand how VARTECH Technology can work incredibly well for your Gas Turbine, it is important to understand varnish and the problem it creates.

Varnish is a broad term covering various kinds of deposits in oil systems. Some types are rigid and firm, others sticky, and others are commonly referred to as sludge. However, the common factor is that they typically begin from the degradation of the oil in the system.

Varnish usually forms and sticks in areas that are extremely hot or very cool and sluggish.

Now, measuring or finding varnish is an enormous challenge since varnish does not turn up in the oil, but on the metal surfaces. The only way to identify varnish is to see it on a surface or to experience its effect. For example, a sticky valve is an apt indicator of the presence of varnish.

It is triggered in many ways. The cycle of varnish begins with something that upsets the lubricant’s stability, such as excessive heat. This can lead to the degradation of the oil, resulting in the formation of impurities. For a while, these impurities often remain dissolved in the oil, causing no harm. But, as more and more accrue, however, they stick together, forming insoluble, suspended submicron particles and once they stick to metal surfaces, they become varnish.

Varnish accumulation reduces a lubricant’s heat transfer properties and causes your system to run hotter and hotter. The consequences won’t just jeopardise your equipment — it will cause de-rated equipment, unpredicted shutdowns, inefficient operation, enhanced maintenance labor management, and spending, higher costs, and lost profits for the owner.

In some turbines, varnish focuses on servo valves, causing them to stick and either delay movement or refuse to move, which can send the turbine out of operation, causing a complete shutdown. In a peaking turbine, one that is held in reserve for peak demand, stuck servo valves can lead to failure to start. Downtime and repair costs can run anywhere from $100,000 into the millions.

Varnish buildup in gas turbines is a big concern for our industrial lubricant customers. While some cleaners in the market are effective in certain circumstances, they may also present several issues. But, VARTECH Technology has addressed the issues of greatest concern, namely water separability; oxidation stability; and seal compatibility.

Residual dispersal/detergent cleaner remaining in the oil system when the oil is changed can ruin the fresh oil that is installed. To ensure that the cleaner is expunged from the system, a full flush is required.

This is where VARTECH™ Industrial System Cleaner (ISC), can come into play. A non-solvent-based solution that can be added straight to oil during operation, VARTECH technology cleans varnish and sludge from the system before a regular oil change. In exhaustive lab testing against existing products, Chevron VARTECH™ ISC showed very good seal compatibility, water/oil separability, and oxidation performance.

To understand how VARTECH Technology can be an incredibly easy method that works for your gas turbine, we can take a case in point of offshore production platforms with three turbines on board. The turbine in question had a severe varnish issue and the oil cooler had been contaminated, rendering the temperature rise to where the operators would have to shut the turbine down to replace the cooler.

VARTECH ISC was added and over one hour, the main oil header temperature dropped around 10 degrees, from too high to normal. The product had an immediate effect on the operating conditions of the oil cooler. In comparison, when the previous dispersant/ detergent product was used, it took two days to see a temperature drop.

That product was also blocking the filters in the system frequently with varnish debris. VARTECH ISC had no such filter plugging effect over the two-day test period. Subsequent testing continued, it revealed that VARTECH ISC outperformed many other commonly used cleaners in cleaning efficiency, effectiveness, and system compatibility without drastically affecting water separability and oxidation stability. This compatibility also reduces the performance impact for the fresh oil when flushing is unfeasible, and it does not need to be used in combination with a varnish filtration system. It is not recommended not to leave any varnish cleaner in a system indefinitely. Simply add VARTECH ISC before a scheduled oil change, and the removed varnish debris will come out with the old oil.  

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VARTECH™ TECHNOLOGY – HOW RELIABLE IS YOUR EQUIPMENT AGAINST FLUID DEGRADATION?

Fluid degradation is bound to cause many kinds of equipment failures. A lubricant in service is often subjected to a broad range of conditions which can degrade its base oil and additive system. Such factors include heat, entrained air, incompatible gases, moisture, internal or external contamination, process constituents, radiation, and unplanned mixing of a different fluid.

However, today’s users of industrial lubricants are up against other challenges. Chief among them is deciphering the nature of the deposits or varnishes. Often, just by looking at the brown color of a deposit, one assumes it must be the same as the brown sample that was previously observed. These assumptions are risky since they can lead to taking the wrong corrective actions.

This is where utmost precaution needs to be taken and a careful plan of action followed.  

First, it is imperative that we broaden our thinking of sludge or varnish. This material is not just simply the oxidation or degradation products from the lubricant - it is the material coming out of the fluid with the potential to cause operational issues. Equipment reliability issues are not only caused by fluid degradation and varnish deposits but also by any material that is not a homologous single phase with the lubricant. Therefore, any foreign material causing deposits in the lubricant can potentially be categorized in this category.

Since there are many mechanisms that weaken lubricants, sorting deposits into classification bins is helpful to better discern the source of the deposits and determine the right remediation process.

Next, there is a need to carry out the root cause analysis (RCA) to identify what happened, why it happened, and what can be done to stop it from happening again. It involves examining the problem and considering proof from several viewpoints.

Often, the deposit components can also be spotted within the in-service fluid. Also, the overall condition of the fluid speaks volumes about the formation direction.

After accumulating as much data as possible about the fluid condition, the deposit can be characterized. A proper analysis of the deposit is often the root cause determination itself. Specifying the deposit source classification will help establish the actions to take when fixing the cause. Several times, the deposit contains over one deposit classification. That information can support this root cause determination.

With a root cause and deposit classification designated, one can focus the efforts toward the elimination and removal of the tar-ball deposits. The chemistry of the deposit details the mitigation strategy since any one deposit removal technology is incapable of removing all deposits. Also, it is often favorable to cease the deposit formation before trying to discard it.

This is when industrial operators need to take notice of VARTECH Industrial System Cleaner (ISC), a two-step, clean-and-control solution that uses proprietary technology to carry out efficient cleaning without creating operational constraints to protect equipment from varnish and ensure peak productivity in the operation. The advanced lubrication chemistry used in VARTECH Technology also inhibits the formation of varnish precursors, products of oil degradation that can deposit on internal surfaces and build up. You get exceptional oxidation stability, less degradation, and long oil life—a breakthrough approach to varnish control.

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SLUDGE AND VARNISH DEPOSITS – IS THERE A WAY TO BEAT IT?

It is tempting to dismiss and often underestimate varnish as just another soft, sticky, grimy contaminant that clings to gas turbines. Yet, in-depth research and studies have proven otherwise. There is a side to this rather innocuous-looking grime that makes every energy corporation bring its most innovative and resilient technology forth.

A coating that adheres to internal surfaces, varnish and sludge deposits can wear out equipment components, restrict performance and ultimately cause failures. Taking different forms, from a sticky coating to a hard lacquer, and ranging in color from gray to brown to amber, the varnish is very destructive and hard to remove. These reasons are enough to realize that in order to vanquish varnish, one must really understand it.

Oxidation resulting from the thermal stressing of lubricating oil, and the products of oxidation, can lead to the creation of varnish in hydraulic control and lubricating oil systems. After oxidation and the development of free radicals into a merged form of varnish, these sticky deposits cling to the metal surfaces of the oil loop, namely piping, valves, heat exchangers, strainers, filters, and other sensitive equipment.

In turn, this growing film seizes other fine particulates on the sticky surface, which continues to build up around the particulates, forming an abrasive, destructive surface. Research has shown that deposits of polymerized oil oxidation products contribute to the weakening of gaskets and mechanical seals.

Other potential problems caused by the varnish in turbine systems include restriction and sticking of moving mechanical parts; increased component wear; increased friction, heat, and energy due to varnish's thermal insulation effect; autocatalytic deterioration of the lubricant; plugging of small oil flow orifices and oil strainers; reduction in filter efficiency and potential filter plugging; journal bearing failure; increased maintenance costs because of cleanup and disposal of oil.

Heat is the root cause of varnish. Without an efficient removal system for oil oxidation products, the varnish contamination level in the oil will unavoidably grow until it beats the capability of the inhibitors. For every 10°C rise in operating oil temperature, the rate of oil oxidation doubles. Microdieseling is one cause of hot spots in the oil. This is the shrinking of entrained air bubbles when the oil passes through a high-pressure pump in the hydraulic circuit. Another cause of hot spots is the production of spark discharges. This powerful heat caused by static discharges literally cooks the oil, creating oil molecule fragments that exhaust antioxidant additives.

Even gas turbines that push peaking units with low operating hours are not immune to oil oxidation and varnish formation. Rolling the turbines with the turning gear two to four hours every week reduces rotor bowing, and maintaining the circulation of lube oil at all times sustains reliability and availability. But, with these benefits comes the unfavorable side effect of furthering lube oil oxidation and varnishing.

Despite knowing the key factors involved in causing varnish, detailed research has proven that the application of traditional oil test methods as an early warning for the onset of oil varnish is either futile or provides limited information.

Conventional oil cleaning methods that include strainers, centrifuges, vacuum dehydrators, and mechanical media filtration are effective in removing water and hard contaminants, along with some larger soft contaminants. However, removing varnish and the by-products of oil oxidation that form varnish requires the removal of the insoluble submicron soft oxidation products. The most effective method is continuous electrostatic oil cleaning, which addresses contamination well beyond conventional means.

This is where Vartech industrial cleaner makes a difference. A two-step, clean-and-control solution with high saving potential. VARTECH Industrial System Cleaner is an inimitable blend of triple action technology and a streamlined cleaning process. Vartech technology uses advanced lubrication chemistry which hinders the development of varnish precursors, products of oil degradation that can deposit on internal surfaces and accumulate over time. In short, one gets remarkable oxidation stability, less degradation, and long oil life, which can not only lead to varnish control but also maximize operational efficiency while ensuring high cost-efficiency and time saving.

Lastly, if you are looking to vanquish varnish and sludge deposit, then look no further than Vartech Industrial System Cleaner. It is the answer to your every question related to varnish.