How effective is varnish removal solutions? 

Oil degradation produces submicron particles that cluster and bind to metal surfaces transforming into what’s known as varnish. The accumulated build-up of varnish from oil breakdown can cause serious problems and setbacks in industrial turbines, hydraulic systems and compressors.

 

Sludge, often the most common type of varnish that originates from the degradation of the oil in the system, forms and sticks in areas that are very hot or very cool and stagnant due to no flow area.

 

If this is left untreated, varnish can lead to various levels of equipment failure, costly operation downtime and pricey repairs or complete replacement that can run costs from hundreds of thousands to millions. All of this can be mitigated through the removal of varnish.

 

The challenge is when varnish builds-up it becomes difficult to detect or measure. Equipment operators should have an oil analysis program such as the MPC testing (Membrane Patch Colorimetry). Though this can only check the precursors of varnish, an indicator if the oil may be breaking down. The only way to know you have varnish for sure is to see it on a surface or to experience its effect.

 

If this is left untreated, varnish can lead to various levels of equipment failure, costly operation downtime and pricey repairs or complete replacement that can run costs from hundreds of thousands to millions. All of this can be mitigated through the removal of varnish.

 

Another way of removing varnish is through solvents, dispersants or synthetic solvency enhancers. In addition to the commercial chemical products, several filtration technologies including depth media, balanced charge agglomeration and adsorptive resin can be used to remove varnish precursors from the oil before it sticks to surfaces.

 

However, solvents don't tend to stay in the oil for long as they're designed to evaporate in a short period of time. They may also raise the risk of combustion due to lowering the flashpoint of the oil by as much as 93 degrees Celsius.

 

Detergents or dispersants on the other hand may change certain fundamental characteristics of the oil. Another downside is that the chemistry tends to attack antioxidants and reduce lifespan making them incompatible with the oil.

 

As for solvency enhancers, their effectiveness remains a big question as they work better as a varnish preventative seeing they are not very aggressive at cleaning varnish off surfaces.

 

While all of these have proven effective in removing varnish precursors from the oil to a different extent, they can also take away helpful additives from the oil including foam inhibitors, rust inhibitors and extreme pressure performance enhancers. 

 

Read more about VARTECH™ ISC varnish remover or contact your Caltex Lubricants representative to learn more.

Paul Sly
Paul Sly is a Technical Advisor for Chevron with a BS in Mechanical Engineering and CLS and OMA-1 certifications in the lubricants field. His career includes 13 years at Caterpillar Engine Division and 18 years at Chevron, including managing the ISOCLEAN® contamination control program for the past decade and as Chevron’s top field specialist in the power generation industry for both turbine and reciprocating engine applications. This field experience has built his reputation as a subject matter expert in turbine oil, including varnish issues, hydraulics, gas engines, compressors and gear boxes supporting Chevron and customer operations around the globe.

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