Reliability Articles

How to Mitigate Your Varnish?

In the previous newsletters about Varnish, we already talked about how varnish is generated in your oil, how to detect it and how it will affect your equipment and oil. So now with this knowledge we will now figure out how to mitigate your varnish problem.

Varnish which generated in oil can be in two states, soluble or insoluble state. So there are technologies out there to address varnish in both soluble and insoluble state.

Insoluble State Varnish

As you can see in figure 1, about solubility, the lower ther temperature of the oil, more likely the varnish will be in insoluble state, so this technologies will be most suited to be used when the oil temperature (in oil tank or operating temperature) is lower than 40o C.


1. Depth Membrane Filtration

Depth membrane filtration technology is what we called as filter on day to day basis. This type of technology is simple and economical to operate. Filters are very good at capturing large particles (including insoluble varnish) especially when you used a fine filter size such as a 3 micron with high beta ratio. When using a very fine filter the challenge is the pressure drop, so this is why having a fine filter is suggested in kidney loop or offline filtration system.

2. Electrostatic Oil Cleaning

Electrostatic oil cleaning technology works by giving charge to oil’s contaminant either positively or negatively. When the contaminants are flowing to electrostatic oil cleaner, the positively charged particle will be drawn to negatively charged pole and vice versa. Neutral contaminants are drawn and deposited by gradient force to the edge of the die electric media.

When filters are struggling to remove fine particles, with how Electrostatic Oil Cleaning technology works, it is better at removing fine particles including small insoluble varnish and soot .

3. Balance Charged Agglomeration

Balance Charge Agglomertaion technology works by splitting the fluid flow into two streams and then charging the contaminants inside with opposite charges, positive and negative charge, after that this two stream recombined and mixed in turbulent flow. The positively charged contaminants will be drawn to negatively charged contaminants and agglomerate into larger particles. Having a larger particles means it can be easier to be removed with Depth Membrane Filtration technology.

Cleaning varnish at insoluble state only effective when it is done at lower temperature, which is a challenge, because most of our equipment oil runs at temperature more than 40o C. This will limit the ability of this technologies to clean varnish at your system.

Soluble State Varnish

In soluble state, varnish can be removed with chemical filtration. Chemical filtration works by using a specific blends media resin that chemically targets and removes the contaminants through strong adsorption forces. Just like how a silica gel works to adsorp moisture in air. This media resins targets the soluble varnish in your oil.

Fluid Enhancement

Another way to remove varnish is with adding Fluid Enhancer Products such as Boost VR from Fluitech. Boost VR, when added to your oil will increase the saturation limit of your oil so it can hold more dissolved varnish. When combined with a Chemical Filtration Technology, it will greatly increase the time needed to clean up your whole system.