A New Algorithm for Scheduling Condition-Based Maintenance of Gas Turbines

Author(s):  
Yavuz Yılmaz ◽  
Rainer Kurz ◽  
Ayşe Özmen ◽  
Gerhard-Wilhelm Weber

In developed electricity markets, the deregulation boosted competition among companies participating in the electricity market. Therefore, the enhanced reliability and availability of gas turbine systems is an industry obligation. Not only providing the available power with minimum operation and maintenance costs, but also guaranteeing high efficiency are additional requisites and efficiency loss of the power plants leads to a loss of money for the electricity generation companies. Multivariate Adaptive Regression Spline (MARS) is a modern methodology of statistical learning, data mining and estimation theory that is significant in both regression and classification is a form of flexible non-parametric regression analysis capable of modeling complex data. In this study, single shaft, 6MW class industrial gas turbines located at various sites have been monitored. The performance monitoring of a gas turbine consisted of hourly measurements of various input variables over an extended period of time. Using such measurements, predictive models for gas turbine heat rate and the gas turbine axial compressor discharge pressure values have been generated. The measured values have been compared with the values obtained as a result of the MARS models. The MARS-based models are obtained with the combination of gas turbine performance input and target variables and the complementary meteorological data. The results are presented, discussed, and conclusions are drawn for modern energy and cost efficient gas turbine and power plant maintenance management as the outcomes of this study.

2014 ◽  
Vol 136 (07) ◽  
pp. 38-43
Author(s):  
Lee S. Langston

This article focuses on the use of gas turbines for electrical power, mechanical drive, and marine applications. Marine gas turbines are used to generate electrical power for propulsion and shipboard use. Combined-cycle electric power plants, made possible by the gas turbine, continue to grow in size and unmatched thermal efficiency. These plants combine the use of the gas turbine Brayton cycle with that of the steam turbine Rankine cycle. As future combined cycle plants are introduced, we can expect higher efficiencies to be reached. Since almost all recent and new U.S. electrical power plants are powered by natural gas-burning, high-efficiency gas turbines, one has solid evidence of their contribution to the greenhouse gas reduction. If coal-fired thermal power plants, with a fuel-to-electricity efficiency of around 33%, are swapped out for combined-cycle power plants with efficiencies on the order of 60%, it will lead to a 70% reduction in carbon emissions per unit of electricity produced.


Author(s):  
Richard Curtis ◽  
Warren Miglietti ◽  
Michael Pelle

In recent years, orders for new land-based gas turbines have skyrocketed, as the planning, construction and commissioning of new power plants based on combined-cycle technology advances at an unprecedented pace. It is estimated that 65–70% of these new equipment orders is for high-efficiency, advanced “F”, “G” or “H” class machines. The W501F/FC/FD gas turbine, an “F” class machine currently rated at 186.5 MW (simple cycle basis), has entered service in significant numbers. It is therefore of prime interest to owners/operators of this gas turbine to have sound component refurbishment capabilities available to support maintenance requirements. Processes to refurbish the Row 1 turbine blade, arguably the highest “frequency of replacement” component in the combustion and hot sections of the turbine, were recently developed. Procedures developed include removal of brazed tip plates, coating removal, rejuvenation heat treatment, full tip replacement utilizing electron beam (EB) and automated micro-plasma transferred arc (PTA), joining methods, proprietary platform crack repair and re-coating. This paper describes repair procedure development and implementation for each stage of the process, and documents the metallurgical and mechanical characteristics of the repaired regions of the component.


Author(s):  
Donald A. Kolp ◽  
Harold A. Guidotti ◽  
William M. Flye

Of all the external factors affecting a gas turbine, inlet pressure and temperature have the greatest impact on performance. The effect of inlet temperature variations is especially pronounced in the new generation of high-efficiency gas turbines typified by the 40 MW GE LM6000. A reduction of 50 F (28 C) in inlet temperature can result in a 30% increase in power and a 4.5% improvement in heat rate. An elevation increase to 5000 feet (1524 meters) above sea level decreases turbine output 17%; conversely supercharging can increase output more than 20%. This paper addresses various means of heating, cooling and supercharging LM6000 inlet air. An economic model is developed and sample cases are cited to illustrate the optimization of gas turbine inlet systems, taking into account site conditions, incremental equipment cost and subsequent performance enhancement.


1995 ◽  
Vol 117 (3) ◽  
pp. 513-527 ◽  
Author(s):  
D. A. Kolp ◽  
W. M. Flye ◽  
H. A. Guidotti

Of all the external factors affecting a gas turbine, inlet pressure and temperature have the greatest impact on performance. The effect of inlet temperature variations is especially pronounced in the new generation of high-efficiency gas turbines typified by the 40 MW GE LM6000. A reduction of 50°F (28°C) in inlet temperature can result in a 30 percent increase in power and a 4.5 percent improvement in heat rate. An elevation increase to 5000 ft (1524 m) above sea level decreases turbine output 17 percent; conversely supercharging can increase output more than 20 percent. This paper addresses various means of heating, cooling and supercharging LM6000 inlet air. An economic model is developed and sample cases are cited to illustrate the optimization of gas turbine inlet systems, taking into account site conditions, incremental equipment cost and subsequent performance enhancement.


Author(s):  
Axel W. von Rappard ◽  
Heinz G. Neuhoff ◽  
Salvatore A. Della Villa

Power and heat rate, and exhaust gas and noise emissions are commonly used to evaluate the performance of power generation equipment. Recently, reliability, availability and maintainability (RAM) are being widely adopted as more significant evaluation criteria for gas turbine power plants. All the criteria are used to evaluate new equipment and the measurements on previous installations are the basis for expected values. What differentiates RAM from the other three criteria is the duration of the measurements. Collecting and processing of RAM data is different since it needs to be collected during normal operation of the plant and over a long period of time. This means it is a coordinated effort of both partners; the customers and the manufacturers. This paper provides a summary of results over a period of four years with a review of the data and conclusions concerning the actual operation. It shows that gas turbine plants can be operated with high reliability and availability requirements. Outages can be reduced in both frequency and length, if the service management is based on the shared information of a worldwide RAM field data collection. A coordinated communication line is a prerequisite for sharing this information. The exchange of information is also mandatory if short reaction time for improvements is required. The planning for the implementation of the communication tools is presented in detail in terms of a ‘road map’ of this program.


2014 ◽  
Vol 137 (1) ◽  
Author(s):  
James Spelling ◽  
Rafael Guédez ◽  
Björn Laumert

A thermo-economic simulation model of a hybrid solar gas-turbine (HSGT) power plant with an integrated storage unit has been developed, allowing determination of the thermodynamic and economic performance. Designs were based around two representative industrial gas-turbines: a high efficiency machine and a low temperature machine. In order to examine the trade-offs that must be made, multi-objective thermo-economic analysis was performed, with two conflicting objectives: minimum investment costs and minimum specific carbon dioxide (CO2) emissions. It was shown that with the integration of storage, annual solar shares above 85% can be achieved by HSGT systems. The levelized electricity cost (LEC) for the gas-turbine system as this level of solar integration was similar to that of parabolic trough plants, allowing them to compete directly in the solar power market. At the same time, the water consumption of the gas-turbine system is significantly lower than contemporary steam-cycle based solar thermal power plants.


Author(s):  
Christian Vandervort ◽  
David Leach ◽  
David Walker ◽  
Jerry Sasser

Abstract The power generation industry is facing unprecedented challenges. High fuel costs and increased penetration of renewable power have resulted in greater demand for high efficiency and operational flexibility. Imperatives to reduce carbon footprint place an even higher premium on efficiency. Power producers are seeking highly efficient, reliable, and operationally flexible solutions that provide long-term profitability in a volatile environment. New generation must also be cost-effective to ensure affordability for both domestic and industrial consumers. Gas turbine combined cycle power plants meet these requirements by providing reliable, dispatchable generation with a low cost of electricity, reduced environmental impact, and broad operational flexibility. Start times for large, industrial gas turbine combined cycles are less than 30 minutes from turning gear to full load, with ramp rates from 60 to 88 MW/minute. GE introduced the 7/9HA industrial gas turbine product portfolio in 2014 in response to these demands. These air-cooled, H-class gas turbines (7/9HA) are engineered to achieve greater than 63% net combined cycle efficiency while delivering operational flexibility through deep, emission-compliant turndown and high ramp rates. The largest of these gas turbines, the 9HA.02, is designed to exceed 64% combined cycle efficiency (net, ISO) in a 1×1, single-shaft (SS) configuration. As of December 2018, a total of 32 7/9HA power plants have achieved COD (Commercial Operation Date) while accumulating over 220,000 hours of operation. These plants operate across a variety of demand profiles including base load and load following (intermediate) service. Fleet leaders for both the 7HA and 9HA have exceeded 12,000 hours of operation, with multiple units over 8,000 hours. This paper will address four topics relating to the HA platform: 1) gas turbine product technology, 2) gas turbine validation, 3) integrated power plant commissioning and operating experience, and 4) lessons learned and fleet reliability.


Author(s):  
Michael Welch

Abstract Many parts of the world are facing the triple challenge of providing secure energy to fuel economic growth at an affordable cost while minimizing the impact of energy production on the environment. Island nations especially struggle to address this trilemma, as renewable resources are usually limited and fossil fuels imported. Traditionally such distributed power plants have relied on liquid fuels and multiple open cycle reciprocating engines to provide both redundancy and the ability to load follow across a broad load range to maximize efficiency. This approach has created high electricity prices and significant negative environmental impact, especially that attributed to CO2, NOx, and SOx. With increasing natural gas production, the availability of Liquefied Petroleum Gas (LPG) has grown, and costs have fallen, allowing the potential to switch from fuel oils to LPG to reduce environmental impacts. Energy costs and environmental impact can be further reduced by using high efficiency Gas Turbine Combined Cycle plants with dry low emissions combustion technology. However, a further hurdle facing many locations is lack of the fresh water required for combined cycle operations. LPG-fuelled Gas Turbine Combined Cycle using Organic Rankine Cycle (ORC) technology can address all aspects of this energy trilemma. This paper reviews the conceptual design of a proposed 100MW distributed power plant for an island location, based on multiple LPG-fuelled gas turbines to follow load demand, with an ORC bottoming cycle to maximize efficiency.


Energies ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 3110 ◽  
Author(s):  
Pavel Atănăsoae

Distributed generation is a good option for future energy systems with respect to sustainable development. In this context, the small-scale combined heat and power (CHP) plants are seen as an efficient way to reduce greenhouse gas emissions due to lower fuel consumption compared to the separate generation of the heat and electricity. The objective of this paper is to establish operating strategies of the small-scale CHP plants to reduce operational cost and increase revenue in liberalized electricity markets. It analyzes a cogeneration plant with organic Rankine cycle and biomass fuel under the conditions of the Romanian electricity market and the green certificates support scheme for electricity generated in high efficiency cogeneration and from renewable sources. The main finding is that choosing an appropriate mode of operation and using correlated prices of heat and electricity can increase the trading profitability of a CHP plant in liberalized power markets. This can be done by an analysis of the particularities and the specific operating conditions of the CHP plant. The results show that the operating strategies of the CHP plant can yield substantial net revenues from electricity and heat sales. The CHP plant can be economically operated to a useful heat load of more than 40% when operating strategies are applied.


Author(s):  
B. Becker ◽  
B. Schetter

Commercial IGCC power plants need gas turbines with high efficiency and high power output in order to reduce specific installation costs and fuel consumption. Therefore the well proven 154 MW V94.2 and the new 211 MW V94.3 high temperature gas turbine are well suited for this kind of application. A high degree of integration of gas turbine, steam turbine, oxygen production, gasifier and raw gas heat recovery improves the cycle efficiency. The air used for oxygen production is taken from the gas turbine compressor. The N2-fraction is recompressed and mixed with the cleaned gas prior to combustion. Both features require modifications of the gas turbine casing and the burners. Newly designed burners using the coal gas with its very low heating value and a mixture of natural gas and steam as a second fuel are developed for low NOx and CO emissions. These special design features are described and burner test results presented.


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