Prevention and Removal of Varnish
Essential for Turbine Power Plants
When GE issued its Technical Information Letter five years ago, regarding Lube Oil Varnishing in all heavy-duty gas turbines (including power plants) it came down on the side of so-called "balanced charge agglomeration" as a means to solve the problem. In fact, GE began selling varnish removal systems that used the BCA technology. Among their recommendations GE pointed out that the technology worked to mitigate as well as prevent the effects of varnishing.
Why is this news today? Even after five years, there is still a lot of confusion about the severity of the contamination problem, whether the various base oils impact the effects, and which technology works the best. The Parker SMR System utilizes BCA technology to prevent build up of sludge and varnish while operating off line with continuous circulation of system fluid. The engineers at Sorensen Systems have described the benefits as basically:
- Extending the life of the oil by removing impurities
- Improving oil and system clean up
- More reliable operation of turbine accessory systems
Balanced Charge Agglomeration Technology
The various SMR (sub-micron removal) machines from Parker remove sub-micron particles at 2-10 GPM. The process uses the patented BCA technology to remove both hard and soft particles from oils at sub-micron levels. The BCA technology maintains hydraulic and lubricating fluids in optimum condition preventing and removing the build-up of sludge and varnish. The machines are available in simplified or PLC control formats.
Eliminate Turbine Trips/Outages
According to the engineers at ISOPur Fluid Technologies, the extreme gas turbine operating conditions cause an increase in lubricating oil degradation and contamination. This high stress on the oil leads to sticky deposits, the so-called "varnish" on close-clearance mechanical components resulting in servo valve problems and associated turbine trips. The majority of these varnish deposits have been shown to originate as sub-micron particles within the oil.
Remove the Contaminants but Leave the Additives
One of the strongest recommendations for BCA technology over competing approaches is BCA does not adversely affect the additives with the oil because only non-soluble particles are removed. In most cases, the BCA technology improves the conditions that most additives are designed to change. Some of the benefits of BCA technology are:
- Removal of pre-existing varnish
- Sub-micron particle removal
- Function with water present
- Enhances current filtration
- Quick oil and system clean up
- Extended equipment life
Steam Turbine Solution
A major pharmaceutical company in New England, which operates four steam turbines in its power plant, was experiencing outages at a frequent rate and turbine overhauls at a much too frequent rate as well. Even though the lubricating oil in the turbines was changed at least once a year, it still experienced bearing failures at an alarming rate. The decision was made to try something different.
After the power plants were equipped with SMR systems to address the sludge and varnish issue, the changes were dramatic. Oil analysis after the installation of the system indicated a significant drop in contamination levels over the first several weeks. After two and a half years one of the turbines was opened for inspection and overhaul. Previous overhauls involved removing several inches of sludge and algae from the bottom of the oil sump. This time, the inspection presented clean internals of the oil sump and pipes. The large oil return lines from the main bearings were also very clean and required no maintenance. In short, the entire system was so spotless that no cleaning was necessary.