Degradation Effects on Combined Cycle Power Plant Performance—Part I: Gas Turbine Cycle Component Degradation Effects

2003 ◽  
Vol 125 (3) ◽  
pp. 651-657 ◽  
Author(s):  
A. Zwebek ◽  
P. Pilidis
Keyword(s):  
Gas Turbine ◽  
Combined Cycle ◽  
Plant Performance ◽  
Plant Design ◽  
Turbine Performance ◽  
Fortran Code ◽  
Steam Turbine Plant ◽  
Combined Cycle Plant ◽  
Gas Turbine Exhaust ◽  
Topping Cycle

This paper describes the effects of degradation of the main gas path components of the gas turbine topping cycle on the combined cycle gas turbine (CCGT) plant performance. First, the component degradation effects on the gas turbine performance as an independent unit are examined. It is then shown how this degradation is reflected on a steam turbine plant of the CCGT and on the complete combined cycle plant. TURBOMATCH, the gas turbine performance code of Cranfield University, was used to predict the effects of degraded gas path components of the gas turbine have on its performance as a whole plant. To simulate the steam (bottoming) cycle, another Fortran code was developed. Both codes were used together to form a complete software system that can predict the CCGT plant design point, off-design, and deteriorated (due to component degradation) performances. The results show that the overall output is very sensitive to many types of degradation, especially in the turbine of the gas turbine. Also shown is the effect on gas turbine exhaust conditions and how this affects the steam cycle.

Degradation Effects on Combined Cycle Power Plant Performance: Part 1 — Gas Turbine Cycle Component Degradation Effects

2001 ◽  
Author(s):  
A. Zwebek ◽  
P. Pilidis
Keyword(s):  
Gas Turbine ◽  
Combined Cycle ◽  
Plant Performance ◽  
Plant Design ◽  
Turbine Performance ◽  
Fortran Code ◽  
Steam Turbine Plant ◽  
Combined Cycle Plant ◽  
Gas Turbine Exhaust ◽  
Topping Cycle

This paper describes the effects of degradation of the main gas path components of the gas turbine topping cycle on the Combined Cycle Gas Turbine (CCGT) plant performance. Firstly the component degradation effects on the gas turbine performance as an independent unit are examined. It is then shown how this degradation is reflected on a steam turbine plant of the CCGT and on the complete Combined Cycle plant. TURBOMATCH, the gas turbine performance code of Cranfield University was used to predict the effects of degraded gas path components of the gas turbine have on its performance as a whole plant. To simulate the steam (Bottoming) cycle, another Fortran code was developed. Both codes were used together to form a complete software system that can predict the CCGT plant design point, off-design, and deteriorated (due to component degradation) performances. The results show that the overall output is very sensitive to many types of degradation, specially in the turbine of the gas turbine. Also shown is the effect on gas turbine exhaust conditions and how this affects the steam cycle.

Combined Turbine Equipment Performance

2007 ◽  
Author(s):  
Anthony E. Butler ◽  
Jagadish Nanjappa
Keyword(s):  
Steam Turbine ◽  
Gas Turbine ◽  
Reference Conditions ◽  
Combined Cycle ◽  
Plant Performance ◽  
Turbine Generator ◽  
Combined Cycle Plant ◽  
Turbine Equipment ◽  
Gas Turbine Exhaust ◽  
Equipment Performance

“Combined Turbine Equipment Performance” represents the combined performance of the Gas Turbine-Generator(s) and the Steam Turbine-Generator(s), while disregarding or holding the performance of the remaining equipment in the Power Plant at its design levels. The lack of established industry standards and methods addressing the manner in which combined turbine equipment performance should be determined has invited confusion and has created opportunities for technical errors to go undetected. This paper presents a method and the supporting theory by which the corrected performance of the turbine-generators within a combined cycle plant can be combined to gauge their combined performance levels for either contractual compliance or for diagnostic purposes. The Combined Turbine Equipment Performance methodology provided in this paper, allows the performance engineer to easily separate the performance contribution of each turbine generator from the overall plant performance. As such, this information becomes a powerful diagnostic tool in circumstances where a reconciliation of overall plant performance is desired. Individual (gas or steam) turbine performance can be determined by conducting a test in accordance with the respective test code (ASME PTC 22 or PTC 6.2). However, each of these test codes corrects the measured equipment performance to fundamentally different reference conditions. Where the gas turbine-generator measured performance is corrected primarily to ambient reference conditions, the steam turbine-generator measured performance is corrected to steam flows and other steam reference conditions. The simple mathematical addition of the corrected performance of each turbine ignores the well-known fact that the steam turbine-generator output in a combined cycle plant is impacted by the gas turbine exhaust conditions, in particular the gas turbine exhaust flow and temperature. The purpose of this paper is to provide a method for the determination of “Combined Turbine Equipment Performance”, review the supporting theory, highlight the assumptions, and develop useful transfer functions for some commonly used combined cycle plant configurations, and bound the uncertainty associated with the methodology.

Degradation Effects on Combined Cycle Power Plant Performance—Part II: Steam Turbine Cycle Component Degradation Effects

2003 ◽  
Vol 125 (3) ◽  
pp. 658-663 ◽  
Author(s):  
A. Zwebek ◽  
P. Pilidis
Keyword(s):  
Power Plant ◽  
Steam Turbine ◽  
Gas Turbine ◽  
Heat Recovery ◽  
Combined Cycle ◽  
Plant Performance ◽  
Graphical Form ◽  
Plant Design ◽  
Heat Recovery Steam Generator ◽  
Fortran Code

This is the second paper exploring the effects of the degradation of different components on combined cycle gas turbine (CCGT) plant performance. This paper investigates the effects of degraded steam path components of steam turbine (bottoming) cycle have on CCGT power plant performance. Areas looked at were, steam turbine fouling, steam turbine erosion, heat recovery steam generator degradation (scaling and/or ashes deposition), and condenser degradation. The effect of gas turbine back-pressure on plant performance due to HRSG degradation is also discussed. A general simulation FORTRAN code was developed for the purpose of this study. This program can calculate the CCGT plant design point performance, off-design plant performance, and plant deterioration performance. The results obtained are presented in a graphical form and discussed.

Degradation Effects on Combined Cycle Power Plant Performance: Part 2 — Steam Turbine Cycle Component Degradation Effects

2001 ◽  
Author(s):  
A. Zwebek ◽  
P. Pilidis
Keyword(s):  
Power Plant ◽  
Steam Turbine ◽  
Gas Turbine ◽  
Heat Recovery ◽  
Combined Cycle ◽  
Plant Performance ◽  
Graphical Form ◽  
Plant Design ◽  
Heat Recovery Steam Generator ◽  
Fortran Code

This is the second paper exploring the effects of the degradation of different components on Combined Cycle Gas Turbine (CCGT) plant performance. This paper investigates the effects of degraded steam path components of steam turbine (bottoming) cycle have on CCGT power plant performance. Areas looked at were, steam turbine fouling, steam turbine erosion, heat recovery steam generator degradation (scaling and/or ashes deposition), and condenser degradation. The effect of gas turbine back-pressure on plant performance due to HRSG degradation is also discussed. A general simulation Fortran code was developed for the purpose of this study. This program can calculate the CCGT plant design point performance, off-design plant performance, and plant deterioration performance. The results obtained are presented in a graphical form and discussed.

PerformanceAnalysis of Integrated Solar Combined Cycle Power Plant for Dhahran, Saudi Arabia

2014 ◽  
Vol 492 ◽  
pp. 568-573 ◽  
Author(s):  
Yinka Sofihullahi Sanusi ◽  
Palanichamy Gandhidasan ◽  
Esmail M.A. Mokheimer
Keyword(s):  
Saudi Arabia ◽  
Gas Turbine ◽  
Combined Cycle ◽  
Plant Performance ◽  
Steam Turbines ◽  
Steam Generation ◽  
Power Requirement ◽  
Gas Turbine Exhaust ◽  
Auxiliary Heater ◽  
Solar Field

Saudi Arabia is blessed with abundant solar energywhichcan be use to meet its ever increasing power requirement. In this regard, the energy analysis and plant performance of integrated solar combined cycle (ISCC) plant with direct steam generation (DSG) was carried out for Dhahran, Saudi Arabia using four representative months of March, June, September and December. The plant consists of 180MW conventional gas turbine plant and two steam turbines of 80MW and 60MW powered by the solar field and gas turbine exhaust. With high insolation during the summer month of June the plant can achieve up to 25% of solar fraction with ISCC plant efficiency of 45% as compared to gas turbine base of 38%.This can however be improved by increasing the number of collectors or/and the use of auxiliary heater .

Combined Heat and Power Plants Based on Mirror Heat Exchange Brayton Cycles

2014 ◽  
Author(s):  
Andrea Passarella ◽  
Gianmario L. Arnulfi
Keyword(s):  
Heat Recovery ◽  
Power Plants ◽  
Combined Heat And Power ◽  
Combined Cycle ◽  
Plant Performance ◽  
Higher Power ◽  
Combined Cycle Plant ◽  
Gas Turbine Exhaust ◽  
Interesting Alternative ◽  
Top Cycle

As gas turbine exhaust gases leave the turbine at high temperature, heat recovery is often carried out in a combined heat-and-power system or in the steam section of a combined-cycle plant. An interesting alternative is a mirror cycle, which involves coupling together a direct Brayton top cycle and an inverted Brayton bottom cycle; this results in significantly higher power output and efficiency, though at the expense of added complexity. The research illustrated in the present paper was based on two in-house codes and aimed to analyze different plant configurations, one of which was a heat recovery (regenerative) top cycle with the heat exchanger hot side located between the top and bottom cycle turbo-expanders. The authors call this configuration a distorting mirror, as the hot side may not be at atmospheric pressure. A parametric analysis was carried out in order to optimize plant performance vs. pressure levels. Simulation showed that, at the design point, very good performance is obtained: efficiency close to 0.50 with plant cost (per megawatt) about half vs. combined-cycle plants. An off-design analysis showed that the mirror plant is a little more sensitive to changes in load than a simple Brayton, single-shaft GT.

scholarly journals Repowering Fossil Steam Power Plants With Combustion Turbine-Based Technologies

1996 ◽  
Author(s):  
Stanley Pace ◽  
Arden Walters
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Power Plants ◽  
Combined Cycle ◽  
Environmental Benefits ◽  
Technology Selection ◽  
Original Plant ◽  
Generation Capacity ◽  
Gas Turbine Exhaust ◽  
Topping Cycle

Increased competition fostered by changes in legislation governing power generation entities has engendered a need to closely assess the economics of operating older-electric generating units. Decisions must be made as to whether these units should be retired and replaced with new, greenfield generation capacity, whether capacity should be purchased from other generation companies, or whether such units should be repowered in some way. The repowering alternative has merit when economic factors and environmental considerations show it to project the least cost of electricity over other choices. The chief advantages of repowering, include use of existing real estate and infrastructure, existing transmission facilities and staffing. Since the repowered plant usually emits less stack gas pollutants per unit of energy generated then the original plant, environmental benefits can also accrue. Various types of gas turbine based repowering options for steam electric plants are presented. All the approaches discussed involve the addition of gas turbines to the cycle and the consequent benefit of some form of combined cycle operation. This option includes boiler retirement (and replacement with combined cycle), hot or warm windbox repowering (the boiler is retained and a gas turbine topping cycle is added), feedwater heating repowering (the gas turbine exhaust heats feedwater), and site repowering (only the site infrastructure is re-used as the site for a combined cycle). Business considerations are discussed in terms of their impact on the decision to repower and technology selection. An example involving feedwater heater repowering is used to illustrate the interaction between the business and technical aspects of repowering.

scholarly journals Exergy Analysis of Two Second-Generation SCGT Plant Proposals

1998 ◽  
Author(s):  
A. Corti ◽  
L. Failli ◽  
D. Fiaschi ◽  
G. Manfrida
Keyword(s):  
Gas Turbine ◽  
Second Generation ◽  
Combined Cycle ◽  
Point Of View ◽  
Specific Power ◽  
Co2 Removal ◽  
Good Efficiency ◽  
Specific Power Output ◽  
Combined Cycle Plant ◽  
Gas Turbine Exhaust

Two different power plant configurations based on a Semi-Closed Gas Turbine (SCGT) are analyzed and compared in terms of First and Second Law analysis. SCGT plant configurations allow the application of CO2 separation techniques to gas-turbine based plants and several further potential advantages with respect to present, open-cycle solutions. The first configuration is a second-generation SCGT/CC (Combined Cycle) plant, which includes inter-cooling (IC) between the two compression stages, achieved using spray injection of water condensed in a separation process removing vapor from the flue gases. The second configuration (SCGT/RE) combines compressor inter-cooling with the suppression of the heat recovery steam generator and of the whole bottoming cycle; the heat at gas turbine exhaust is directly used for gas turbine regeneration. The SCGT/CC-IC solution provides good efficiency (about 55%) and specific power output figures, on account of the spray inter-cooling; however, with this configuration the cycle is not able to self-sustain the CO2 removal reactions and amine regeneration process, and needs a substantial external heat input for this purpose. The SCGT/RE solution is mainly attractive from the environmental point of view: in fact, it combines the performance of an advanced gas turbine regenerative cycle (efficiency of about 49%) with the possibility of a self-sustained CO2 removal process. Moreover, the cycle configuration is simplified because the HRSG and the whole bottoming cycle are suppressed, and a potential is left for cogeneration of heat and power.

Bayesian Calibration for Power Splitting in Single Shaft Combined Cycle Plant Diagnostics

2015 ◽  
Author(s):  
Xiaomo Jiang ◽  
Eduardo Mendoza ◽  
TsungPo Lin
Keyword(s):  
Power Plant ◽  
Steam Turbine ◽  
Gas Turbine ◽  
Combined Cycle ◽  
Plant Performance ◽  
Power Splitting ◽  
Power Split ◽  
Combined Cycle Plant ◽  
Plant Level ◽  
Operational Data

Condition monitoring and diagnostics of a combined cycle gas turbine power plant has become an important tool to improve its availability, reliability, and performance. However, there are two major challenges in the diagnostics of performance degradation and anomaly in a single shaft combined cycle power plant. First, since the gas turbine and steam turbine in such a plant share a common generator, each turbine’s contribution to the total plant power output is not directly measured, but must be accurately estimated to identify the possible causes of plant level degradation. Second, multivariate operational data instrumented from a power plant need to be used in the plant model calibration, power splitting and degradation diagnostics. Sensor data always contains some degree of uncertainty. This adds to the difficulty of both estimation of gas turbine to steam turbine power split and degradation diagnostics. This paper presents an integrated probabilistic methodology for accurate power splitting and the degradation diagnostics of a single shaft combined cycle plant, accounting for uncertainties in the measured data. The method integrates the Bayesian inference approach, thermodynamic physics modeling, and sensed operational data seamlessly. The physics-based thermodynamic heat balance model is first established to model the power plant components and their thermodynamic relationships. The model is calibrated to model the plant performance at the design conditions of its main components. The calibrated model is then employed to simulate the plant performance at various operating conditions. A Bayesian inference method is next developed to determine the power split between the gas turbine and the steam turbine by comparing the measured and expected power outputs at different operation conditions, considering uncertainties in multiple measured variables. The calibrated model and calculated power split are further applied to pinpoint the possible causes at individual components resulting in the plant level degradation. The proposed methodology is demonstrated using operational data from a real-world single shaft combined cycle power plant with a known degradation issue. This study provides an effective probabilistic methodology to accurately split the power for degradation diagnostics of a single shaft combined cycle plant, addressing the uncertainties in multiple measured variables.

Gas Turbine Exhaust Energy Margin in a Combined Cycle Power Plant

2002 ◽  
Author(s):  
Paul B. Johnston
Keyword(s):  
Gas Turbine ◽  
Power Plants ◽  
Risk Mitigation ◽  
Field Testing ◽  
Combined Cycle ◽  
Plant Performance ◽  
Performance Guarantees ◽  
Exhaust Energy ◽  
Gas Turbine Exhaust ◽  
Turbine Exhaust

Margining gas turbine exhaust energy exposes the EPC (Engineering, Procurement & Construction) contractor to risk when developing overall plant performance guarantees. The objective of this paper is to explain the nature of this risk, recognize its significance and propose ways of mitigation. Sharing risk between the Developer and the contractor should be apportioned to maximize value for the project. Attention is focused on 2 on 1 combined cycle power plants, but the results are relevant for all types of gas turbine based power and cogeneration facilities. Risk mitigation alternatives discussed include both assessment of margins to the bottomline performance and the application of performance corrections at the time of field testing. Allowing for corrections leads to enhanced overall plant performance guarantees.

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