Risk-Based Assessment of Unplanned Outage Events and Costs for Combined-Cycle-Plants

2012 ◽  
Author(s):  
Dale Grace ◽  
Thomas Christiansen
Keyword(s):  
Power Systems ◽  
Gas Turbine ◽  
Cash Flow ◽  
Gas Turbines ◽  
Operational Reliability ◽  
Combined Cycle ◽  
Maintenance Costs ◽  
Wide Range ◽  
Turbine Equipment ◽  
The Impact

Unexpected outages and maintenance costs reduce plant availability and can consume significant resources to restore the unit to service. Although companies may have the means to estimate cash flow requirements for scheduled maintenance and on-going operations, estimates for unplanned maintenance and its impact on revenue are more difficult to quantify, and a large fleet is needed for accurate assessment of its variability. This paper describes a study that surveyed 388 combined-cycle plants based on 164 D/E-class and 224 F-class gas turbines, for the time period of 1995 to 2009. Strategic Power Systems, Inc. (SPS®), manager of the Operational Reliability Analysis Program (ORAP®), identified the causes and durations of forced outages and unscheduled maintenance and established overall reliability and availability profiles for each class of plant in 3 five-year time periods. This study of over 3,000 unit-years of data from 50 Hz and 60 Hz combined-cycle plants provides insight into the types of events having the largest impact on unplanned outage time and cost, as well as the risks of lost revenue and unplanned maintenance costs which affect plant profitability. Outage events were assigned to one of three subsystems: the gas turbine equipment, heat recovery steam generator (HRSG) equipment, or steam turbine equipment, according to the Electric Power Research Institute’s Equipment Breakdown Structure (EBS). Costs to restore the unit to service for each main outage cause were estimated, as were net revenues lost due to unplanned outages. A statistical approach to estimated costs and lost revenues provides a risk-based means to quantify the impact of unplanned events on plant cash flow as a function of class of gas turbine, plant subsystem, and historical timeframe. This statistical estimate of the costs of unplanned outage events provides the risk-based assessment needed to define the range of probable costs of unplanned events. Results presented in this paper demonstrate that non-fuel operation and maintenance costs are increased by roughly 8% in a typical combined-cycle power plant due to unplanned maintenance events, but that a wide range of costs can occur in any single year.

Risk-Based Assessment of Unplanned Outage Events and Costs for Combined-Cycle Plants

2013 ◽  
Vol 135 (2) ◽  
Author(s):  
Dale Grace ◽  
Thomas Christiansen
Keyword(s):  
Gas Turbine ◽  
Cash Flow ◽  
Gas Turbines ◽  
Statistical Approach ◽  
Combined Cycle ◽  
Maintenance Costs ◽  
Plant Availability ◽  
The Impact ◽  
Overall Reliability ◽  
Reliability And Availability

Unexpected outages and maintenance costs reduce plant availability and can consume significant resources to restore the unit to service. This paper describes a survey and analysis of unplanned outage events for 388 combined-cycle plants, based on 164 D/E-Class and 224 F-Class gas turbines. The 15-year timeframe included over 3000 unit-years of data. The causes and durations of forced outages and unscheduled maintenance were identified, and overall reliability and availability were established for each class of plant. Costs to restore the unit to service for each main outage cause were estimated, as were net revenues lost due to unplanned outages. A statistical approach to estimated costs and lost revenues provides a risk-based means to quantify the impact of unplanned events on plant cash flow as a function of class of gas turbine and plant subsystem. The risk-based assessment defines the range of probable costs of unplanned outage events.

Uncertainty Analysis of Inflow Conditions on an HPT Gas Turbine Nozzle: Effect on Particle Deposition

2020 ◽  
Author(s):  
R. Friso ◽  
N. Casari ◽  
M. Pinelli ◽  
A. Suman ◽  
F. Montomoli
Keyword(s):  
Gas Turbine ◽  
Energy Efficient ◽  
Gas Turbines ◽  
Particle Deposition ◽  
Operating Conditions ◽  
Wide Range ◽  
And Performance ◽  
Gas Turbine Nozzle ◽  
The Impact ◽  
Inflow Conditions

Abstract Gas turbines (GT) are often forced to operate in harsh environmental conditions. Therefore, the presence of particles in their flow-path is expected. With this regard, deposition is a problem that severely affects gas turbine operation. Components’ lifetime and performance can dramatically vary as a consequence of this phenomenon. Unfortunately, the operating conditions of the machine can vary in a wide range, and they cannot be treated as deterministic. Their stochastic variations greatly affect the forecasting of life and performance of the components. In this work, the main parameters considered affected by the uncertainty are the circumferential hot core location and the turbulence level at the inlet of the domain. A stochastic analysis is used to predict the degradation of a high-pressure-turbine (HPT) nozzle due to particulate ingestion. The GT’s component analyzed as a reference is the HPT nozzle of the Energy-Efficient Engine (E3). The uncertainty quantification technique used is the probabilistic collocation method (PCM). This work shows the impact of the operating conditions uncertainties on the performance and lifetime reduction due to deposition. Sobol indices are used to identify the most important parameter and its contribution to life. The present analysis enables to build confidence intervals on the deposit profile and on the residual creep-life of the vane.

Short-Term Optimization of a Combined Cycle Power Plant Integrated With an Inlet Air Conditioning Unit

2020 ◽  
Author(s):  
Weimar Mantilla ◽  
José García ◽  
Rafael Guédez ◽  
Alessandro Sorce
Keyword(s):  
Power Plant ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Air Conditioning ◽  
Combined Cycle ◽  
Plant Performance ◽  
Mixed Integer ◽  
Environmental Load ◽  
Turbine Inlet ◽  
The Impact

Abstract Under new scenarios with high shares of variable renewable electricity, combined cycle gas turbines (CCGT) are required to improve their flexibility, in terms of ramping capabilities and part-load efficiency, to help balance the power system. Simultaneously, liberalization of electricity markets and the complexity of its hourly price dynamics are affecting the CCGT profitability, leading the need for optimizing its operation. Among the different possibilities to enhance the power plant performance, an inlet air conditioning unit (ICU) offers the benefit of power augmentation and “minimum environmental load” (MEL) reduction by controlling the gas turbine inlet temperature using cold thermal energy storage and a heat pump. Consequently, an evaluation of a CCGT integrated with this inlet conditioning unit including a day-ahead optimized operation strategy was developed in this study. To establish the hourly dispatch of the power plant and the operation mode of the inlet conditioning unit to either cool down or heat up the gas turbine inlet air, a mixed-integer linear optimization (MILP) was formulated using MATLAB, aiming to maximize the operational profit of the plant within a 24-hours horizon. To assess the impact of the proposed unit operating under this dispatch strategy, historical data of electricity and natural gas prices, as well as meteorological data and CO2 emission allowances price, have been used to perform annual simulations of a reference power plant located in Turin, Italy. Furthermore, different equipment capacities and parameters have been investigated to identify trends of the power plant performance. Lastly, a sensitivity analysis on market conditions to test the control strategy response was also considered. Results indicate that the inlet conditioning unit, together with the dispatch optimization, increases the power plant’s operational profit by achieving a wider operational range, particularly important during peak and off-peak periods. For the specific case study, it is estimated that the net present value of the CCGT integrated with the ICU is 0.5% higher than the power plant without the unit. In terms of technical performance, results show that the unit reduces the minimum environmental load by approximately 1.34% and can increase the net power output by 0.17% annually.

Operation Experiences of Siemens IGCC Gas Turbines Using Gasification Products From Coal and Refinery Residues

2000 ◽  
Author(s):  
M. Huth ◽  
A. Heilos ◽  
G. Gaio ◽  
J. Karg
Keyword(s):  
Power Generation ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Combined Cycle ◽  
Strong Impact ◽  
Coal Gas ◽  
Operation Conditions ◽  
Wide Range ◽  
Commercial Operation ◽  
Burner Design

The Integrated Gasification Combined Cycle concept is an emerging technology that enables an efficient and clean use of coal as well as residuals in power generation. After several years of development and demonstration operation, now the technology has reached the status for commercial operation. SIEMENS is engaged in 3 IGCC plants in Europe which are currently in operation. Each of these plants has specific characteristics leading to a wide range of experiences in development and operation of IGCC gas turbines fired with low to medium LHV syngases. The worlds first IGCC plant of commercial size at Buggenum/Netherlands (Demkolec) has already demonstrated that IGCC is a very efficient power generation technology for a great variety of coals and with a great potential for future commercial market penetration. The end of the demonstration period of the Buggenum IGCC plant and the start of its commercial operation has been dated on January 1, 1998. After optimisations during the demonstration period the gas turbine is running with good performance and high availability and has exceeded 18000 hours of operation on coal gas. The air-side fully integrated Buggenum plant, equipped with a Siemens V94.2 gas turbine, has been the first field test for the Siemens syngas combustion concept, which enables operation with very low NOx emission levels between 120–600 g/MWh NOx corresponding to 6–30 ppm(v) (15%O2) and less than 5 ppm(v) CO at baseload. During early commissioning the syngas nozzle has been recognised as the most important part with strong impact on combustion behaviour. Consequently the burner design has been adjusted to enable quick and easy changes of the important syngas nozzle. This design feature enables fast and efficient optimisations of the combustion performance and the possibility for easy adjustments to different syngases with a large variation in composition and LHV. During several test runs the gas turbine proved the required degree of flexibility and the capability to handle transient operation conditions during emergency cases. The fully air-side integrated IGCC plant at Puertollano/Spain (Elcogas), using the advanced Siemens V94.3 gas turbine (enhanced efficiency), is now running successfully on coal gas. The coal gas composition at this plant is similar to the Buggenum example. The emission performance is comparable to Buggenum with its very low emission levels. Currently the gas turbine is running for the requirements of final optimization runs of the gasifier unit. The third IGCC plant (ISAB) equipped with Siemens gas turbine technology is located at Priolo near Siracusa at Sicilly/Italy. Two Siemens V94.2K (modified compressor) gas turbines are part of this “air side non-integrated” IGCC plant. The feedstock of the gasification process is a refinery residue (asphalt). The LHV is almost twice compared to the Buggenum or Puertollano case. For operation with this gas, the coal gas burner design was adjusted and extensively tested. IGCC operation without air extraction has been made possible by modifying the compressor, giving enhanced surge margins. Commissioning on syngas for the first of the two gas turbines started in mid of August 1999 and was almost finished at the end of August 1999. The second machine followed at the end of October 1999. Since this both machines are released for operation on syngas up to baseload.

Expanding Fuel Flexibility in MHPS’ Dry Low NOx Combustor

2018 ◽  
Author(s):  
Katsuyoshi Tada ◽  
Kei Inoue ◽  
Tomo Kawakami ◽  
Keijiro Saitoh ◽  
Satoshi Tanimura
Keyword(s):  
Power Systems ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Environmental Conservation ◽  
Combined Cycle ◽  
Inlet Temperature ◽  
Turbine Inlet Temperature ◽  
Social Perspectives ◽  
Turbine Inlet ◽  
Fuel Flexibility

Gas-turbine combined-cycle (GTCC) power generation is clean and efficient, and its demand will increase in the future from economic and social perspectives. Raising turbine inlet temperature is an effective way to increase combined cycle efficiency and contributes to global environmental conservation by reducing CO2 emissions and preventing global warming. However, increasing turbine inlet temperature can lead to the increase of NOx emissions, depletion of the ozone layer and generation of photochemical smog. To deal with this issue, MHPS (MITSUBISHI HITACHI POWER SYSTEMS) and MHI (MITSUBISHI HEAVY INDUSTRIES) have developed Dry Low NOx (DLN) combustion techniques for high temperature gas turbines. In addition, fuel flexibility is one of the most important features for DLN combustors to meet the requirement of the gas turbine market. MHPS and MHI have demonstrated DLN combustor fuel flexibility with natural gas (NG) fuels that have a large Wobbe Index variation, a Hydrogen-NG mixture, and crude oils.

Dynamic Behaviour of a Vertical Natural Circulation Two Pressure Stage HRSG Behind a Heavy Duty Gas Turbine

2000 ◽  
Author(s):  
Georg N. Stamatelopoulos ◽  
Karl Ponweiser ◽  
Heimo Walter ◽  
Wladimir Linzer ◽  
Hubert Neßler ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Dynamic Behaviour ◽  
Natural Circulation ◽  
Operational Reliability ◽  
Combined Cycle ◽  
Thermal Engineering ◽  
Simulation Code ◽  
Pressure Stage ◽  
Cold Starts

Modern combined cycle gas turbines are highly flexible in their operation, concerning start up, load change and shut down. Heat Recovery Steam Generators (HRSG) arranged downstream of the Gas Turbine (GT) are forced to operate in such a way, that the gas turbine operation is not restricted by them. Therefore, they should be designed for a high cycling capability with typical values in the range of 200 to 250 cold starts, 1000 warm and 2500 hot starts for their typical 25 year life span. Cold starts are defined as a standstill period of over 120 hours, warm starts to a weekend shutdown and hot starts to an overnight shut down. AE Energietechnik GmbH (AE), a Babcock Borsig Power company has specialized in designing, erecting and commissioning vertical natural circulation multiple pressure stage HRSGs. The vertical design combines simplicity and low investment costs with performance reliability and high availability. In order to forecast the dynamic behaviour of such a HRSG, AE has supported the development of a dynamic simulation code at the Institute of Thermal Engineering (ITW) located at the Vienna University of Technology. This finite volume code enables the prediction of velocities, pressures and temperatures for several dynamic processes of the HRSG. In the present paper computational results of starts and load changes will be presented for a vertical natural circulation HRSG. Furthermore, several design optimization changes which where made in order to increase operational reliability and availability will be demonstrated. Finally, practical applications of already constructed HRSG will be discussed and conclusions will be drawn.

Evolution of Gas Turbines Auxiliary Systems Designed for Reliability

1993 ◽  
Author(s):  
Jacek Misiowiec ◽  
Tim McElwee ◽  
Sal DellaVilla
Keyword(s):  
Power Systems ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Operational Reliability ◽  
Design Approach ◽  
Design For Reliability ◽  
Design Evolution ◽  
Low Nox Combustion ◽  
Design Characteristics ◽  
Turbine Design

Gas turbine design evolution and practice is driven by industry demand for increased output and improved operating efficiencies. New aerothermal design characteristics require a focus on improved materials and coatings, and cooling techniques. As environmental issues continue to confront the industry, Dry Low NOx combustion system designs represent a significant opportunity for meeting new emissions requirements. These issues represent opportunity for significant technology improvements and industry driven advances. However, just as important is the design evolution of the Control and Auxiliary systems which support the gas turbine. Historically, these support systems, as demonstrated by the Operational Reliability Analysis Program (ORAP), are typically the primary drivers of plant Availability and Reliability. Following a rigorous “Design for Reliability” approach provides opportunities for ensuring that the design meets three critical requirements: starting reliability, a minimum of unit shutdowns during operating demand periods and ease of maintenance. The design approach for the Control and Auxiliary systems for new turbine design (product improvement) therefore provides an opportunity for developing a uniform and standardized approach which continues to focus on Reliability, Availability, and Maintainability. This design approach also provides opportunities for improved field installation and reduced cycle time, a major benefit for the end user. This paper will describe the “Design for Reliability” approach followed by ABB Power Generation, Inc., and supported by Strategic Power Systems, Inc.® (SPS) for the GT11N2 auxiliary systems. The extension of the ORAP system for auxiliary systems will be discussed as the approach for monitoring unit Availability and Reliability, maintaining configuration control, and for promoting continuous improvement.

Analysis of Indirectly Fired Gas Turbine Power Systems

2007 ◽  
Author(s):  
J. E. Donald Gauthier
Keyword(s):  
Power Generation ◽  
Power Systems ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Turbine Engines ◽  
Inlet Temperature ◽  
Turbine Engine ◽  
Engine Design ◽  
Wide Range ◽  
System Configurations

This paper describes the results of modelling the performance of several indirectly fired gas turbine (IFGT) power generation system configurations based on four gas turbine class sizes, namely 5 kW, 50 kW, 5 MW and 100 MW. These class sizes were selected to cover a wide range of installations in residential, commercial, industrial and large utility power generation installations. Because the IFGT configurations modelled consist of a gas turbine engine, one or two recuperators and a furnace; for comparison purpose this study also included simulations of simple cycle and recuperated gas turbine engines. Part-load, synchronous-speed simulations were carried out with generic compressor and turbine maps scaled for each engine design point conditions. The turbine inlet temperature (TIT) was varied from the design specification to a practical value for a metallic high-temperature heat exchanger in an IFGT system. As expected, the results showed that the reduced TIT can have dramatic impact on the power output and thermal efficiency when compared to that in conventional gas turbines. However, the simulations also indicated that several configurations can lead to higher performance, even with the reduced TIT. Although the focus of the study is on evaluation of thermodynamic performance, the implications of varying configurations on cost and durability are also discussed.

GTPRO: A Flexible, Interactive Computer Program for the Design and Optimization of Gas Turbine Power Systems

1988 ◽  
Author(s):  
Maher A. Elmasri
Keyword(s):  
Power Systems ◽  
Computer Program ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Combined Cycle ◽  
Process Flow ◽  
Technical Parameters ◽  
Design And Optimization ◽  
Trade Offs ◽  
Combined Cycles

A fast, interactive, flexible computer program has been developed to facilitate system selection and design for gas turbine based power and cogeneration plants. A data base containing ISO performance information on forty-two gas turbines is coupled to an off-design model to predict engine characteristics for different site and installation parameters. A heat recovery steam generator (HRSG) model allows boiler size and cost to be estimated as a function of the system’s technical parameters. The model can handle HRSG’s with up to two live steam pressures plus a third feedheating/deaerating drum. Five basic types of combined cycle are covered with up to four different process steam streams for cogeneration or gas turbine injection. Two additional feedheating steam bleeds are supported for condensing combined cycles. The program is intelligent with some internal decision making capabilities regarding process steam sourcing and flow directions and will automatically select the appropriate heat and mass balance procedures to cover a wide variety of process flow schematics. The program provides plotter outputs to show the cycle process flow schematic, T-s and h-s diagrams, and HRSG temperature profiles. An application of GTPRO in analyzing some technical and economic performance trade-offs for two-pressure combined cycles is presented.

scholarly journals Advanced Aeroderivative Gas Turbines in Coal-Based High Performance Power Systems (HIPPS)

1998 ◽  
Author(s):  
F. L. Robson ◽  
D. J. Seery
Keyword(s):  
Power Systems ◽  
Gas Turbine ◽  
Gas Turbines ◽  
High Performance ◽  
Power Plants ◽  
Performance Standards ◽  
Combined Cycle ◽  
Advanced Technology ◽  
Early 21St Century ◽  
Near Term

The Department of Energy’s Federal Energy Technology Center (FETC) is sponsoring the Combustion 2000 Program aimed at introducing clean and more efficient advanced technology coal-based power systems in the early 21st century. As part of this program, the United Technologies Research Center has assembled a seven member team to identify and develop the technology for a High Performance Power Systems (HIPPS) that will provide in the near term, 47% efficiency (HHV), and meet emission goals only one-tenth of current New Source Performance Standards for coal-fired power plants. In addition, the team is identifying advanced technologies that could result in HIPPS with efficiencies approaching 55% (HHV). The HIPPS is a combined cycle that uses a coal-fired High Temperature Advanced Furnace (HITAF) to preheat compressor discharge air in both convective and radiant heaters. The heated air is then sent to the gas turbine where additional fuel, either natural gas or distillate, is burned to raise the temperature to the levels of modern gas turbines. Steam is raised in the HITAF and in a Heat Recovery Steam Generator for the steam bottoming cycle. With state-of-the-art frame type gas turbines, the efficiency goal of 47% is met in a system with more than two-thirds of the heat input furnished by coal. By using advanced aeroderivative engine technology, HIPPS in combined-cycle and Humid Air Turbine (HAT) cycle configurations could result in efficiencies of over 50% and could approach 55%. The following paper contains descriptions of the HIPPS concept including the HITAF and heat exchangers, and of the various gas turbine configurations. Projections of HIPPS performance, emissions including significant reduction in greenhouse gases are given. Application of HIPPS to repowering is discussed.

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