Has your steam turbine outage been postponed?

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Many turbine outages this spring have been postponed, and we have a solution to provide peace of mind and mitigate the risk of postponed maintenance.

Your turbine may now be at the point where damage to the internal components could accelerate during this extra runtime. Or perhaps the turbine is operating optimally and the postponed outage was intended to satisfy time-based maintenance requirements. Regardless of how your turbine was operating prior to the postponed inspection, a Running Condition Assessment can provide you (or your insurance company) with the peace of mind that the unit is not nearing a failure point, and provide you with the information needed to properly re-schedule your future outage date.

A Running Condition Assessment allows you to assess the health of your turbine generator while the unit is in operation.

This assessment typically includes one specialized technician and equipment at your facility for 3 – 5 days, minimizing the people and time on-site as compared to a standard turbine inspection.

After completion of the Running Condition Assessment you will receive a detailed report on the current condition of your turbine, providing you with vital information for future decision-making.

To learn more about our Running Condition Assessment program, CLICK HERE.

To request a quote and check availability for a Running Condition Assessment, CLICK HERE.

Steam Turbine Valve Inspections

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We recently performed work for a U.S. utility on one of their Main Stop Valves for a GE Steam Turbine.  We can perform valve inspections on-site or in our dedicated steam turbine valve facility in Gainesville, Georgia.  If the valves are inspected at our Gainesville facility we have the ability to make any necessary repairs, reverse engineer and manufacture components, as well as offer material upgrades for longer service life.  We also have an in-house nitriding furnace that allows to control the schedule and provide quick turnarounds on any parts that require a nitrided surface.   We have full capabilities to provide our customers with a turnkey valve service and help extend the life of your steam turbine valves.

Alstom STF Steam Turbines

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We perform all types of inspections on the legacy Alstom STF Steam Turbine Fleet.  Below is a photo of the IP Inner Casing being moved during a C Inspection.   We can perform A, B, and C inspections on the STF fleet, and many of our team members are former Alstom personnel that have the knowledge required to successfully execute these projects.  Please contact us for all of your STF steam turbine outage planning and execution needs.

Steam Turbine Rotor

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Another industrial steam turbine rotor prepped and ready to ship out for repairs. Our field teams do a fantastic job executing turnkey steam and gas turbine outages. Contact us today to help you plan for your next inspection.

Steam Turbine Major Inspection

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We’re lifting the LP upper half casing on a Westinghouse Steam Turbine.   Great attention to detail and planning is required to perform a safe, quality lift of this nature.  Nice job team!

Steam Turbine Low-Speed Balance

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Our Steam Path Repair facility in Pevely, Missouri has many steam turbine rotors that come through each and every year.  One of the services we offer to our customers after repairs have been performed is a low speed balance.  You can see the process in action here on a 3-bearing steam turbine rotor for a turbine that is rated at approximately 80MWs.

Measure the Cause, Not the Symptom

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Directly measuring bearing metal temperature is the most effective way to really determine if a bearing is running hot. Bearing oil drain temperatures are still being utilized on older machines. By the time the bearing oil drain temperature has increased, the bearing may have already been compromised (wiped). PSG recommends that these older machines should have temperature probes (thermocouples or RTD’s) installed in the bearing Babbitt to properly monitor performance. A two-level alarm is recommended (not automatic trip). The first alarm should be set a few degrees above the highest temperature in the recommended normal operating range. Operators should closely monitor bearing temperature after the first alarm sounds. If the temperature rises abruptly and unexpectedly, the bearing may have been compromised and immediate action needs to be taken. Gradual temperature changes which trigger the alarm may be the result of other factors but are still a concern and should be thoroughly investigated. The second alarm should be set at the maximum operating temperature of the bearing material. Operators should manually trip the unit in a controlled manner as soon as possible after this second alarm sounds and determine the cause. The critical temperatures for each of the two levels can be supplied by the manufacturer or recommended by PSG for your individual unit configuration. Different temperature ranges are recommended for Tilt Pad, Elliptical, Short Elliptical and Thrust bearings. Measuring drain oil temperature is too slow and too imprecise to effectively minimize your overall cost of maintenance. Retrofit your machine and save your bottom line.

The Ugly Effects of Water in Lube Oil

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Free and emulsified water are the two most harmful conditions in a lubricating system. The incompressibility of water overrides the hydrodynamic oil film that protects bearings, leading to excessive wear. As little as one percent water in oil can reduce the life expectancy of a journal bearing by as much as 90 percent.

Water will also degrade the life of your lubricant. Moisture contamination can promote the oxidation of the oil by up to 10 times, breaking down the hydrocarbon chains and decreasing the lubricating properties.

Oils containing some types of additives are even more vulnerable to water contamination. Sulfurous AW and EP type additives and phenolic antioxidants are readily broken down by water. This not only destroys their usefulness, but the destruction forms acids which can corrode soft metals such as Babbitt, bronze and brass. The copper, lead, and tin released from this corrosion are catalytic metals which actually accelerate the process. Even synthetic oils containing dibase esters and phosphate esters are not immune. These compounds are known to react with water and form acids, increasing corrosion and degrading the base stock.

Water can disperse other additives such as demulsifying agents, detergents and rust inhibitors, resulting in sludge and sediment buildup, filter plugging and poor oil/water demulsibility.

There is no safe level of water contamination. While maintaining contamination below the saturation point will reduce the levels of free and emulisified water, any amount will start the cycle of degradation.

We recommend that you send a lube oil sample out for analysis on a monthly basis. Then read their report very carefully, noting all metals and water contamination. The service should also provide a narrative of the findings. If you need any help in interpreting the report, please contact us at Ask Mr. Turbine.

Click Here to ask your own question of TGM’s Mr. Turbine or call the 24 Hour Hotline at 888.MrTurbine (888.678.8724)

Inadequate Oil Supply: Measure the Cause, Not the Symptom

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This is Part Three of a three part series on steam turbine tips, discussing the challenge of inadequate oil supply.

Directly measuring bearing metal temperature is the most effective way to really determine if a bearing is running hot. 

Bearing oil drain temperatures are still being utilized on older machines.  By the time the bearing oil drain temperature has increased, the bearing may have already been compromised (wiped). PSG recommends that these older machines should have temperature probes (thermocouples or RTD’s) installed in the bearing Babbitt to properly monitor performance.

Inadequate Oil Supply - Part ThreeA two-level alarm is recommended (not automatic trip). Consequently, the first alarm should be set a few degrees above the highest temperature in the recommended normal operating range.  Operators should also closely monitor bearing temperature after the first alarm sounds.

Keep in mind that if the temperature rises abruptly and unexpectedly, the bearing may have been compromised and immediate action needs to be taken. Gradual temperature changes which trigger the alarm may be the result of other factors but are still a concern and should be thoroughly investigated.

The second alarm should be set at the maximum operating temperature of the bearing material.  Operators should manually trip the unit in a controlled manner as soon as possible after this second alarm sounds and determine the cause.

The critical temperatures for each of the two levels can be supplied by the manufacturer or recommended by PSG for your individual unit configuration. Different temperature ranges are recommended for Tilt Pad, Elliptical, Short Elliptical, and Thrust bearings.

Measuring drain oil temperature is too slow and too imprecise to effectively minimize your overall cost of maintenance. Taking all of this into consideration, the best practice is to retrofit your machine and save your bottom line.

Do you have questions about your steam turbine backup system? Contact PSG today to explore how we can provide support and maintenance options to help you avoid backup system problems.

Inadequate Oil Supply: Don’t Kill Your Turbine on Startup

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This is Part Two of a three part series on steam turbine tips, discussing the challenge of inadequate oil supply.

Your lube oil temperature needs to be lower at startup and shutdown than at full speed to reduce potential issues.

Your turbine’s rotor does not actually ride on the surfaces of its bearings. It rides on a thin film of oil between the rotor and the bearing. At high turbine speeds the rotor hydroplanes across the oil, eliminating contact with the Babbit of the bearing. The heat generated by the turbine decreases the viscosity of the oil and increases its “slipperiness”, which is important at high speeds.

Inadequate Oil Supply - Part TwoAs the rotor slows down, the oil needs to be more viscous to repel the force towards the bearing.

Failure to lower the lube oil temperature (and therefore increase viscosity) can result in light bearing wipes or smearing. These conditions would occur during turning gear operation, unit startup and unit coast down during shutdown.

The ideal lube oil temperature at these lower speeds is 90 degrees Farenheit. Of course, oil temperature can also be too cold on startup—similar to trying to start your car on a cold winter day. Operational personnel are ultimately responsible for maintaining this lower lube oil temperature by regulating water through the lube oil coolers.

Maintaining lube oil cooler cleanliness is also very important for turbine startups.  The tubes must be clean to allow the efficient transfer of heat. Also, as a best practice the bundles should be cleaned every two (2) years.  Lube oil coolers are the single most common area for contaminants to hide.

By following these tips, you can ensure the efficient startup of your turbine, as well as greatly reduce any potential operational issues or challenges.

Do you have questions about your steam turbine backup system? Contact PSG today to explore how we can provide support and maintenance options to help you avoid backup system problems.