pwr_october-2024 - Cover3

ADVERTORIAL
Increased Gas Turbine Reliability
through Optimized Lubrication
No matter your thoughts on renewable, sustainable electricity
production, most electricity generation is still done
by fossil fuel fired power plants. In the United States, natural
gas-fueled gas turbine generators dominate with over
40% of utility-scale electricity production. In order for these
plants to operate most efficiently and maintain the high degree
of reliability demanded by the power grid, effective
and thorough maintenance and reliability programs are required.
Optimized lubrication programs and high-quality
lubricants are key factors in any effective maintenance and
reliability program which helps lower the total cost of ownership
of the equipment.
As in any piece of rotating equipment, contamination
and oxidation of the lubricant will have meaningful, negative
impact on the operation and reliability of gas turbines.
Contamination can develop from a variety of sources,
and they can wreak havoc on equipment:
● Particulate contaminants may be circulated through
the oil system causing abrasive and erosive wear
throughout.
● Water contamination of the lubricant can increase risk
of corrosion of internal surfaces, dilute the oil (decreasing
lubricating and protective properties), and increase
the propensity of the oil to create varnish.
Oxidation is the process by which the lubricating oil degrades
with use and time, independent of any contamination.
Lubricant oxidation requires elevated oil temperature
and exposure of the lubricant to an oxygen source, which is
most commonly ambient air. Oxidation rate increases with
increasing lubricant temperature.
The results of oil oxidation include:
● increased acidity
● reduced lubricity
● increased varnish formation and with extreme oxidation,
a noticeable increase in lubricant viscosity
All of these physical changes to the oil reduce lubrication
of and protection for the equipment. Varnish formation is
also especially significant for gas turbines due to the intricate
oil circulation system, and tight clearances in bearings
and regulation valves.
Reliability and maintenance Best Practices include the
use of proper lubricant particle filtration, desiccant and/or
deliquescent breathers to prevent water intrusion, and increased
lubricant reservoir residence time and/or oil cooler
circuits to reduce bulk oil temperature. These efforts will
greatly mitigate the issues described above, but to obtain
the best operational and reliability results, the turbine must
be serviced with a premium quality, high-performance
lubricant. The most common turbine oils are low-performance
lubricants made from petroleum-derived, mineral
base oils. The mineral oil-based lubricants are often selected
because of lower purchase price, however, there is no
other advantage to mineral-based lubricants. The quality
of mineral oil-based lubricants has increased meaningfully
over the past few decades, though, as additive chemistry
and lubricant technology has advanced. However, the primary
performance limitation of mineral lubricants remains
the same: the mineral base stocks.
Lubricants that use synthetic hydrocarbon (instead of
mineral hydrocarbon) base oils offer superior performance
across all lubrication parameters. Mineral-based lubricants
have improved since much of the non-synthetic lubricant
market has moved from Group I to Group II base stocks,
especially concerning oxidation resistance of the lubricant,
but mineral turbine oils cannot match the lubricity, stability,
and oxidation resistance of high-quality, synthetic lubricants.
A
premium synthetic turbine lubricant like Royal Purple
Synfilm GT, provides excellent water separation and cleanliness
(lack of particulates) as benefits, in addition to the enhanced
lubrication ability provided by a synthetic lubricant.
Gas turbine reservoirs commonly hold thousands of gallons
of lubricant and can accumulate hundreds of gallons
of water from combustion by-products and moist ambient
air. The water will stay emulsified with mineral and lower
quality synthetic turbine oils. The resulting water/oil mixture
degrades the lubricant (reduced viscosity, diluted additives,
greater propensity for varnish formation, etc.), and
carries potentially corrosion-causing water throughout the
turbine. When a lubricant readily sheds water, that water
can be drained from the bottom of the oil reservoir, leaving
dry, high-quality lubricant to continue servicing the turbine.
Also, a lubricant that is already very clean at time of installation
will reduce the risk of abrasive and erosive wear in
the turbine.
Improving the lubrication programs and lubricants that
service gas turbines provide many benefits. Lower purchase
price is the only reason that lower quality lubricants
dominate the market. To justify
increased lubricant/lubrication
costs, the Total Cost of Ownership
of the equipment must
be considered along with lubricant
purchase price. The
increased reliability due to
optimized lubrication and premium
lubricants results in less
unscheduled downtime, reduce
total maintenance costs, and increased
equipment productivity,
all of which greatly surpass
the higher price of better lubrication.
royalpurple.com
https://us-west-2.protection.sophos.com/?d=royalpurple.com&u=aHR0cDovL3JveWFscHVycGxlLmNvbQ==&i=NjE0MGViZWFmZjY2YmUxMDUyNjhhMzBj&t=cHBMV1kyc1BjSlhHaGRJb1JNNk5xL1h5UEx4M00rcThKbVBZdmx6K25Icz0=&h=a6adf34e3bb6414b8d10b59bc4a9826d&s=AVNPUEhUT0NFTkNSWVBUSVadq_qbM_bbHRXukWIgQ0llF2GC53fO8I3a1Jr-AH0w0Q
pwr_october-2024

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