In this day and age with daily revenues for power and oil & gas producers exceeding $1 million (and in many cases over $5 million), it has become imperative to tackle machinery problems before an unplanned shutdown. Yet, in the author’s experience, this is rarely the case. However, through the increased accuracy and quality of instrumentation and data collection, it is much easier to diagnose potential issues (via proactive maintenance) before a failure.
A centrifugal compressor, packaged by Cooper Industries (now part of Rolls-Royce), was used in an offshore facility to compress natural gas. It was a three-stage assembly: from 6 kg/cm3 to 90 kg/cm3 with two stages combined in the low pressure (LP) bundle and a third stage separately operating in the high pressure (HP) bundle assembly.
During load operations, a gas turbine is characterized by cyclic transients and long dwell times. As a result, variation in clearance occurs. Tight clearances in both the compressor and the turbine section are the key to high efficiency. However, some clearance must be maintained in order to avoid contact between rotating and stationary parts.
For rolling element bearings that are not lubricated by a forced lubrication system, there are a few methods available to the user. Oil mist has been presented as the best method of lubricating bearings. It is the best and has some advantages.
The US Department of Energy (DOE) is providing $4,998,319 in funding for ten university research projects on making gas turbines more durable and fuel-flexible, covering the lion's share of the total project costs of $6,314,361.
The funds are granted as part of the Office of Fossil Energy's University Turbine Systems Research (UTSR) Program. DOE is the main financer of the projects, while the remaining costs will be provided by the universities.
In the third part of this series, the author pointed out that natural gas proved to be a good fuel in larger locomotive units and they ran well for long periods of time between overhauls. In this article, he talks about the prospects of the GT-EL locomotives in this era.
Complete predictive maintenance monitoring of gas turbines requires trends of compressor, gas generator and power turbine performance to optimize run times between maintenance cycles.
The end users of ‘best of the best’ turbines optimize their gas turbine performance monitoring methodology to extend their run times significantly beyond vendor’s recommendations (by as much as 60,000 hours). This requires review of vendor’s performance monitoring capabilities during the bid stage of the project and complete performance monitoring capabilities.
Tilting pad radial bearings provide stability at any load angle. Lemon bore (elliptical) or offset sleeve (to achieve an elliptical arrangement) bearings do not eliminate vibration instabilities if the load angle lies in the major axis of the ellipse, since the oil film stiffness in this region may not be sufficient to prevent vibration instabilities.
In the first part of this series, we saw that the present conditions are most favorable for the GT-EL, a clean burning train hauling machine, to make a comeback and become a winner. In this article, the author discusses how UPRR, GE and ALCO came together on the first locomotive and tested it.
There is an old saying that goes like this: "What goes around comes around". This adage could very well apply to the reintroduction of the gas turbine-electric locomotive (GT-EL) in the USA driven by and fueled by the new abundant supply of shale natural gas brought about by fracking.
An $18 million program to install a state-wide microgrid, powered by distributed gas-fired turbines, has recently been launched in the US coastal state of Connecticut, to keep the lights on in public buildings during grid outages in severe weather. The scheme comes after hurricane Sandy last year caused 5 deaths in the state, and $68 billion in damages nationwide.
The gas turbine, at first glance, appears to be a very complicated piece of rotating equipment. Part of the reason for this perception is due to the complexity and number of the various support systems involved. The accessory gearbox is a very critical piece of equipment, since it provides power take-offs to the majority of support system pumps, starters and blowers.
Americans used more natural gas, solar panels and wind turbines, and less coal to generate electricity in 2012, according to the most recent U.S. energy charts released by Lawrence Livermore National Laboratory. Natural gas use is up particularly in the electricity generation sector, where it has basically substituted directly for coal, while sustained low natural gas prices have prompted a shift from coal to gas in the electricity generating sector, according to A.J. Simon, an LLNL energy systems analyst.
Air pollution in China is a serious issue now – the nation burns roughly as much coal as the rest of the world combined. According to a study published recently in a leading U.S. scientific journal, pollution from coal has reduced the average life expectancy of northern China’s 500 million citizens by a full five years. The study, which appeared in the Proceedings of the National Academy of Sciences of the U.S., was based on data compiled between 1980 and 2000.
A gas turbine is a dynamic internal combustion engine. When we compare the performance of a gas turbine to that of a steam turbine, it becomes immediately evident that steam turbine performance is much easier to calculate, since both the vapor and the vapor conditions are fixed.
In coming years, natural gas will continue to be one of the leading fuels for power generation in Texas, but its growth as a fuel source will be dependent on a complex relationship with renewable energy resources, sources told Platts. According to the Electric Reliability Council of Texas -- which represents 85 percent of the state's electric load -- in 2012, gas accounted for almost 45 percent of electric power generation in the ERCOT region. Coal, the second most popular fuel for power generation, had about a 34 percent share, while wind had about 12 percent share.
Condensing and extraction steam turbine efficiency determination requires the calculation of the driven equipment power. This calculation can be inaccurate due to the many variables involved. Installing a torquemeter during the project phase will ensure accurate efficiency calculations for all condensing and extraction condensing steam turbines.
U.S. President Barack Obama recently said global warming is the biggest threat facing the nation and the world. In his State of the Union address in February, he asserted that "we must do more to combat climate change." His policies have been contested by some prominent scientists. Among them is Steve Goreham, Executive Director of the Climate Science Coalition of America, a non-political association focused on science and energy economics.
In June 2013, keynote speakers at PowerGen Europe in Vienna urged European governments to cooperate on a framework that would invigorate the sluggish power market. They called on policymakers to consider the "age of technologies" when deciding on sources of power to support and called for an end to "uncertain legislation-making."
Compressor degradation is the major cause of output and efficiency loss in a gas turbine. "Degradation reduces the air mass flow and pressure ratio, thus reducing power output,” said Jean-Pierre Stalder, head of new product development for Turbotect Ltd. Fouling is a major contributor of degradation. According to Stalder, it accounts for much higher losses than aging. He pointed out that enough air passes through the compressor on a 172 MW turbine in one year to make up a column that is the size of a football field, rising 1,320 miles high.
Schedule delays can prompt some vendors to offer field mechanical tests as an alternative to specified shop tests. Field testing exposes turbines to situations not encountered in FAT testing (piping and foundation stresses) which lead to decision delays and possible acceptance of less than reliable equipment.
Clean energy will be the second largest global source of electricity by 2016 after coal, according to a new report from the International Energy Agency (IEA). At its second annual Medium-Term Renewable Energy Market Report, the agency said that by the year 2016 clean energy will overtake natural gas to become the second largest source of energy in the world. Only coal will generate more electricity than clean energy within three years, the IEA projects.
Siemens Energy has completed two combined cycle power plants (CCPP) Hemweg 9 and Diemen 34 in the Netherlands. Dutch utility Nuon, a part of Vattenfall, has officially inaugurated the 440MW Hemweg 9 located in the Westport district to the west of Amsterdam's center and 435MW (260MW thermal capacity) Diemen 34 CCPP situated to the east of Amsterdam about 15km from Hemweg.