A Case Study of Optimizing Combined Cycle Performance at Kalaeloa

Author(s):  
Helmer Andersen

Fuel is by far the largest expenditure for energy production for most power plants. New tools for on-line performance monitoring have been developed for reducing fuel consumption while at the same time optimizing operational performance. This paper highlights a case study where an online performance-monitoring tool was employed to continually evaluate plant performance at the Kalaeloa Combined Cycle Power Plant. Justification for investment in performance monitoring tools is presented. Additionally the influence of various loss parameters on the cycle performance is analyzed with examples. Thus, demonstrating the potential savings achieved by identifying and correcting the losses typically occurring from deficiencies in high impact component performance.

Author(s):  
Komandur S. Sunder Raj

The objectives of an effective power plant performance monitoring program are several-fold. They include: (a) assessing the overall condition of the plant through use of parameters such as output and heat rate (b) monitoring the health of individual components such as the steam generator, turbine-generator, feedwater heaters, moisture separators/reheaters (nuclear), condenser, cooling towers, pumps, etc. (c) using the results of the program to diagnose the causes for deviations in performance (d) quantifying the performance losses (e) taking timely and cost-effective corrective actions (f) using feedback techniques and incorporating lessons learned to institute preventive actions and, (g) optimizing performance. For the plant owner, the ultimate goals are improved plant availability and reliability and reduced cost of generation. The ability to succeed depends upon a number of factors such as cost, commitment, resources, performance monitoring tools, instrumentation, training, etc. Using a case study, this paper discusses diagnostic techniques that might aid power plants in improving their performance, reliability and availability. These techniques include performance parameters, supporting/refuting matrices, logic trees and decision trees for the overall plant as well as for individual components.


Author(s):  
Michael McClintock ◽  
Kenneth L. Cramblitt

Monitoring thermal performance in the current generation of combined cycle power plants is frequently a challenge. The “lean” plant staff and organizational structure of the companies that own and operate these plants frequently does not allow the engineering resources to develop and maintain an effective program to monitor thermal performance. Additionally, in many combined cycle plants the highest priority is responding to market demands rather than maintaining peak efficiency. Finally, in many cases the plants are not designed with performance monitoring in mind, thus making it difficult to accurately measure commonly used indices of performance. This paper describes the performance monitoring program being established at a new combined cycle plant that is typical of many combined cycle plants built in the last five years. The plant is equipped with GE 7FA gas turbines and a GE reheat steam turbine. The program was implemented using a set of easy-to-use spreadsheets for the major plant components. The data for the calculation of indices of performance for the various components comes from the plant DCS system and the PI system (supplied by OSIsoft). In addition to the development of spreadsheets, testing procedures were developed to ensure consistent test results and plant personnel were trained to understand, use and maintain the spreadsheets and the information they produce.


Author(s):  
Iacopo Rossi ◽  
Luca Piantelli ◽  
Alberto Traverso

Abstract The flexibility of power plants is a critical feature in energy production environments nowadays, due to the high share of non-dispatchable renewables. This fact dramatically increases the number of daily startups and load variations of power plants, pushing the current technologies to operate out of their optimal range. Furthermore, ambient conditions significantly influence the actual plant performance, creating deviations against the energy sold during the day-ahead and reducing the profit margins for the operators. A solution to reduce the impact of unpredicted ambient conditions, and to increase the flexibility margins of existing combined cycles, is represented by the possibility of dynamically controlling the temperature at compressor intake. At present, cooling down the compressor intake is a common practice to govern combined cycle performance in hot regions such as the Middle East and Africa, while heating up the compressor intake is commonly adopted to reduce the Minimum Environmental Load (MEL). However, such applications involve relatively slow regulation of air intake, mainly coping with extreme operating conditions. The use of continuously varying, at a relatively quick pace, the air temperature at compressor intake, to mitigate ambient condition fluctuations and to cope with electrical market requirements, involves proper modeling of the combined cycle dynamic behavior, including the short-term and long-term impacts of intake air temperature variations. This work presents a dynamic modeling framework for the whole combined cycle applied to one of IREN Energia’s Combined Cycle Units. The paper encloses the model validation against field data of the target power plant. The validated model is then used to show the potential in flexibility augmentation of properly adjusting the compressor intake temperature during operation.


Author(s):  
Rodney R. Gay

Traditionally optimization has been thought of as a technology to set power plant controllable parameters (i.e. gas turbine power levels, duct burner fuel flows, auxiliary boiler fuel flows or bypass/letdown flows) so as to maximize plant operations. However, there are additional applications of optimizer technology that may be even more beneficial than simply finding the best control settings for current operation. Most smaller, simpler power plants (such as a single gas turbine in combined cycle operation) perceive little need for on-line optimization, but in fact could benefit significantly from the application of optimizer technology. An optimizer must contain a mathematical model of the power plant performance and of the economic revenue and cost streams associated with the plant. This model can be exercised in the “what-if” mode to supply valuable on-line information to the plant operators. The following quantities can be calculated: Target Heat Rate Correction of Current Plant Operation to Guarantee Conditions Current Power Generation Capacity (Availability) Average Cost of a Megawatt Produced Cost of Last Megawatt Cost of Process Steam Produced Cost of Last Pound of Process Steam Heat Rate Increment Due to Load Change Prediction of Future Power Generation Capability (24 Hour Prediction) Prediction of Future Fuel Consumption (24 Hour Prediction) Impact of Equipment Operational Constraints Impact of Maintenance Actions Plant Budget Analysis Comparison of Various Operational Strategies Over Time Evaluation of Plant Upgrades The paper describes examples of optimizer applications other than the on-line computation of control setting that have provided benefit to plant operators. Actual plant data will be used to illustrate the examples.


Author(s):  
Pablo Andrés Silva Ortiz ◽  
Osvaldo José Venturini ◽  
Electo Eduardo Silva Lora

The increasing trend in global production of petroleum coke (petcoke) is the result of their multiple and innovative industrial applications. From this point of view and also considering the current situation of the traditional energy reserves worldwide, it is important to conduct studies in this area through analysis of the main components of the power plants utilizing this fuel (petcoke). The main target of this study is to realize a techno-economic evaluation of IGCC (Integrated Gasification Combined Cycle) technology, using Brazilian coal, petcoke and a mix of 50% coal and 50% petcoke as fuel. In this paper, the gasification process and the combined cycle are analyzed, considering the implementation of the IGCC technology in the Termobahia power plant. Termobahia is a cogeneration combined cycle power plant, located in the Brazilian state of Bahia that produces 190 MW of electricity and 350 ton/h of steam. The steam produced is sold to an oil refinery (RLAM) located next to it. In first part of this work, the production of the synthesis gas (syngas) from coal gasification was simulated using CeSFaMBi™ software. In the next part, the syngas produced is used to analyze the power plant performance through GateCycle™ software. Finally, the obtained operational and economic parameters are compared with the actual operational parameters of the Termobahia power plant in terms of costs, fuel substitution and combined cycle performance variables, as net power, global efficiency and heat rate.


Author(s):  
Hugh Jin ◽  
Terrence B. Sullivan ◽  
Jeffrey R. Friedman

Gas turbines in combined cycle (CC) power plants, in phased construction situations, usually operate for several months in the simple cycle (SC) mode while the steam portion of the plant is being constructed. At the time of commissioning the combined cycle phase, the gas turbines typically have accumulated a considerable number of operating hours and have possibly experienced some degradation, especially on turbines that have run on dual fuels. To determine the combined cycle new and clean performance, it is necessary to employ a phased testing approach. The phased testing approach involves testing the gas turbines when they are in new and clean condition and combining those results with the measured new and clean steam turbine cycle performance. The method of the phased testing has been introduced in ASME PTC 46 (1996) “Performance Test Code on Overall Plant Performance”. This paper will discuss in detail the test protocol, fundamental equations, corrections, and uncertainty analysis of phased testing. This paper will also discuss performance degradation and engine setting changes between the phases.


2019 ◽  
Vol 141 (12) ◽  
Author(s):  
Iacopo Rossi ◽  
Luca Piantelli ◽  
Alberto Traverso

Abstract The flexibility of power plants is a critical feature in energy production environments nowadays, due to the high share of nondispatchable renewables. This fact dramatically increases the number of daily startups and load variations of power plants, pushing the current technologies to operate out of their optimal range. Furthermore, ambient conditions significantly influence the actual plant performance, creating deviations against the energy sold during the day-ahead and reducing the profit margins for the operators. A solution to reduce the impact of unpredicted ambient conditions, and to increase the flexibility margins of existing combined cycles, is represented by the possibility of dynamically controlling the temperature at compressor intake. At present, cooling down the compressor intake is a common practice to govern combined cycle performance in hot regions such as the Middle East and Africa, while heating up the compressor intake is commonly adopted to reduce the minimum environmental load (MEL). However, such applications involve relatively slow regulation of air intake, mainly coping with extreme operating conditions. The use of continuously varying, at a relatively quick pace, the air temperature at compressor intake, to mitigate ambient condition fluctuations and to cope with electrical market requirements, involves proper modeling of the combined cycle dynamic behavior, including the short-term and long-term impacts of intake air temperature variations. This work presents a dynamic modeling framework for the whole combined cycle applied to one of IREN Energia's Combined Cycle Units. The paper encloses the model validation against field data of the target power plant. The validated model is then used to show the potential in flexibility augmentation of properly adjusting the compressor intake temperature during operation.


Author(s):  
B. Chudnovsky ◽  
L. Levin ◽  
A. Talanker ◽  
V. Mankovsky ◽  
A. Kunin

Diagnostics of large size combined-cycle power plant components (such as: Gas Turbine, HRSG, Steam Turbine and Condenser) plays a significant role in improving power plant performance, availability, reliability and maintenance scheduling. In order to prevent various faults in cycle operation and as a result a reliability reduction, special monitoring and diagnostic techniques is required, for engineering analysis and utility production management. In this sense an on-line supervision system has developed and implemented for 370 MW combined-cycle. The advanced diagnostic methodology is based on a comparison between actual and target conditions. The actual conditions are calculated using data set acquired continuously from the power plant acquisition system. The target conditions are calculated either as a defined actual best operation (Manufacturer heat balances) or by means of a physical model that reproduces boiler and plant performance at off-design. Both sets of data are then compared to find the reason of performance deviation and then used to monitor plant degradation, to support plant maintenance and to assist on-line troubleshooting. The performance calculation module provides a complete Gas Turbine, HRSG and Steam Turbine island heat balance and operating parameters. This paper describes a study where an on-line performance monitoring tool was employed for continuously evaluating power plant performance. The methodology developed and summarized herein has been successfully applied to large size 360–370 MW combined cycles based on GE and Siemens Gas Turbines, showing good capabilities in estimating the degradation of the main equipment during plant lifetime. Consequently, it is a useful tool for power plant operation and maintenance.


Author(s):  
Shane E. Powers ◽  
William C. Wood

With the renewed interest in the construction of coal-fired power plants in the United States, there has also been an increased interest in the methodology used to calculate/determine the overall performance of a coal fired power plant. This methodology is detailed in the ASME PTC 46 (1996) Code, which provides an excellent framework for determining the power output and heat rate of coal fired power plants. Unfortunately, the power industry has been slow to adopt this methodology, in part because of the lack of some details in the Code regarding the planning needed to design a performance test program for the determination of coal fired power plant performance. This paper will expand on the ASME PTC 46 (1996) Code by discussing key concepts that need to be addressed when planning an overall plant performance test of a coal fired power plant. The most difficult aspect of calculating coal fired power plant performance is integrating the calculation of boiler performance with the calculation of turbine cycle performance and other balance of plant aspects. If proper planning of the performance test is not performed, the integration of boiler and turbine data will result in a test result that does not accurately reflect the true performance of the overall plant. This planning must start very early in the development of the test program, and be implemented in all stages of the test program design. This paper will address the necessary planning of the test program, including: • Determination of Actual Plant Performance. • Selection of a Test Goal. • Development of the Basic Correction Algorithm. • Designing a Plant Model. • Development of Correction Curves. • Operation of the Power Plant during the Test. All nomenclature in this paper utilizes the ASME PTC 46 definitions for the calculation and correction of plant performance.


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