Coal, Gas

Turbine Lubrication: Combating Buildup and Improving Reliability

Issue 2 and Volume 118.

Alstom.
Choosing the right lubricant for a plant’s turbines can help improve reliability and reduce long-term costs of operation. Photo courtesy of Alstom.

By Justin Martino, Associate Editor

Power plants represent a large investment for any company, and once a plant is in place the focus should be on the best way to optimize and protect that investment. For owners of power plants, that means finding the way to increase reliability and output.

One of the most essential elements of keeping power generation equipment working at its highest level is lubrication. The proper lubrication and services can help reduce operation and maintenance costs and keep your plant working efficiently, while ignoring the need for proper lubrication maintenance and monitoring can lead to engine breakdowns that lose money not just for repairs, but also lost generation time.

Choosing the correct oil is an important first step in keeping your turbines working at peak performance, according to Wade Flemming, laboratory supervisor at Lubrication Engineers, Inc.

“It’s always a good practice to ensure the lubricant meets the OEM’s (original equipment manufacturer) lubrication specifications for the turbine,” he said. “However, this is only a starting point because most – if not all – gas turbine lubricants on the market today meet major turbine manufacturers’ lubricant requirements. Operators should try to gain any information on how well the lubricant has performed in the field: reach out to other turbine operators for their advice and experience, educate yourself by reading related articles in industry publications and peruse online forums and user groups related to turbine maintenance and lubrication. Try reaching out to industry specialists for information or ask the lubricant manufacturer for any information that they can provide for how well their lubricant performs in the application – such as used oil data – rather than just relying on the data published on the technical sheet.”

Although some lubricants on the market may be designed for a specific turbine, most are designed to meet the needs in several different turbine builds, Flemming said. Most lubricant manufacturers have developed lubricants specifically for gas turbine operations because of problems the industry is seeing with varnish and sludge in gas turbines. Lubricants designed for gas turbines can differ from steam turbine lubricants in the types and concentration of performance additives.

Lubricant Engineers designs several products specifically for gas turbines, including Monolec Turbine Oil 6461 – 6463, which is designed for steam, hydro and gas turbine operations. Flemming said the formula reduces varnish and water contamination while lengthening equipment life and extending drain intervals. It uses a proprietary formula consisting of select low-volatility paraffinic base fluids enhanced with a mix of high performance-additives.

The company also produces Monolec Turbine Oil 6471 – 6472, a gas turbine and turbo compressor lubricant, and Monolec EP Turbine Oil 6476, an anti-wear oil designed specifically for use in gas, steam and hydroelectric mainline turbines driven with or without reduction gears.

Choosing the proper lubricant is just the first step in ensuring reliable performance. From there, the oil must be checked and analyzed.

“There are a lot of factors involved with determining how often a lubricant should be checked, but regular turbine oil monitoring should be part of every turbine operator’s repertoire to ensure reliable operation and peace of mind,” Flemming said. “Setting up an oil monitoring program is essential to predicting when a lubricant is approaching its end of life, giving the operator time to plan for changeout. A turbine lubricant should be analyzed by a reputable lab once per year at the bare minimum – every six months would be ideal.”

Lubrication Engineers offers a Turbine Oil Analysis program, which the company states gives consistent, accurate monitoring of turbine oil for mechanical, operational and environmental factors that can affect the performance and lifespan of the oil and the turbines. The service includes 16 tests that check everything from the oil’s viscosity index to varnish potential.

Plant operators have a wide variety of products and services to choose from when looking at different types of lubricants to use in a facility.
Plant operators have a wide variety of products and services to choose from when looking at different types of lubricants to use in a facility.

While most companies offer assistance in choosing the proper lubricant for a turbine, some companies are using technology to help make the process easier. Shell has several online options for operators looking for lubricants, including its LubeMatch and LubeAdvisor services.

The Shell LubeMatch service is a free self-help with an interactive equipment database that allows customers to access lubrication recommendations at any time. The LubeAdvisor website is a more extensive tool that includes an interactive OEM database, a lubrication survey tool and a lubricant specification database, among other features.

Other services Shell offers to help find the right lubricant include technical helpdesks, field-based Shell LubeAdvisor support, a detailed plant assessment and lubrication surveys.

Shell also offers LubeAnalyst oil condition monitoring. According to Shell, the service is a tool to help operators extend component life and the time between services. The service is designed to reduce costs by indentifying potential oil or component failures before they become critical, extending lubricant life and reducing risks and contributing to reliable operations, according to the company.

Trying to cut costs by purchasing low-quality lubricants is a “false economy,” according to Shell. The company states that lubricant costs are typically less than 5 percent of a power generation business’ total maintenance budget and spending more on services and lubricants can lower an operator’s overall costs by increasing reliability and efficiency.

Companies may also provide both mineral and synthetic oils, and Phillips 66 Lubricants offer a selection of both for plant operators. The company’s mineral oils include Diamond Class Turbine Oil, Diamond Class AW Turbine Oil and Ultra-Clean Turbine Oil, while its synthetic oils include Syncon Turbine Oil and Syndustrial Turbine Oil.

Each type of lubricant is designed for a different application. For the mineral lubricants, Diamond Class Turbine oil is designed for direct drive combined-cycle and co-generation gas turbines and direct-drive steam drives, and Diamond Class AW Turbine Oil is designed for combined-cycle and co-generation gas turbines and gas turbines and steam turbines with gear drives. Ultra-Clean Turbine Oil is designed for direct-drive gas, steam and hydroelectric turbines; centrifugal and rotary air compressors, lightly loaded plain and rolling-element bearings; and vacuum pumps, deep well water pumps and machine tools.

In the synthetic lineup, Syncon Turbine Oil is designed for land-based gas turbines, while Syndustrial Turbine Oil is designed for aero-derivative gas turbines.

DuPont also offers lubricants for a wide variety of applications. Its Krytox Performance Lubricants have been used in the power generation industry since the 1980s for everything from turbine auxiliary systems to power plant maintenance, repair and operations.

The company’s Krytox gearbox grease, which is based on DuPont Teflon PTFE technology, is formulated to lubricate and protect sootblower seals, bearings and gears. Its designed for an extreme temperature range of operation and has the potential for 20 years or more of maintenance-free gearbox operation, according to the company.

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