Incremental Fuel Cost Prediction for a Gas Turbine Combined Cycle Utility

1989 ◽  
Author(s):  
D. Little ◽  
H. Nikkels ◽  
P. Smithson
Keyword(s):  
Gas Turbine ◽  
Fuel Consumption ◽  
Gas Turbines ◽  
Operating Experience ◽  
Load Level ◽  
Combined Cycle ◽  
Operating Conditions ◽  
Fuel Cost ◽  
Ambient Conditions ◽  
Cost Prediction

For a medium sized (300 MW) utility producing electricity from a 130 MW combined cycle, and supplemental 15 MW to 77 MW capacity simple cycle gas turbines, the incremental fuel costs accompanying changes in generating capacity vary considerably with unit, health, load level, and ambient. To enable incremental power to be sold to neighbouring utilities on an incremental fuel cost basis, accurate models of all gas turbines and the combined cycle were developed which would allow a realistic calculation of fuel consumption under all operating conditions. The fuel cost prediction program is in two parts; in the first part, gas turbine health is diagnosed from measured parameters; in the second part, fuel consumption is calculated from compressor and turbine health, ambient conditions and power levels. The paper describes the program philosophy, development, and initial operating experience.

Gas Turbine Part Load Exhaust Gas Emissions Turndown Envelope Testing Methodology

2009 ◽  
Author(s):  
Kristen LeClair ◽  
Thomas Schmitt ◽  
Garth Frederick
Keyword(s):  
Control System ◽  
Gas Turbine ◽  
Fuel Consumption ◽  
Gas Turbines ◽  
Thermodynamic Simulation ◽  
Combined Cycle ◽  
Exhaust Gas ◽  
Ambient Conditions ◽  
Gas Emissions ◽  
Exhaust Gas Emissions

Economic and regulatory requirements have transformed today’s power plant operations. High reserve margins and increased fuel costs have driven combined cycle plants that were once dispatched primarily at base-load to be cycled off during off-peak hours. For many plants, the increased cycling has contributed to shorter maintenance intervals and higher overall operating costs. Technology advancements in combustion system design and in gas turbine control systems has led to extensions in the emissions-compliant operating window of gas turbines, also known as turndown. With extended turndown capability, customers are now able to significantly reduce fuel consumption during minimum load operation at off-peak hours, while simultaneously minimizing the number of shutdowns. Extended turndown reduces operational costs by offsetting the fuel consumption costs against the costs associated with starting up and the maintenance costs associated with such starts. Along with the increased emphasis on turndown capability, there has been a rising need to develop and standardize methods by which turndown capability can be accurately measured and reported. By definition, the limiting factor for turndown is the exhaust gas emissions, primarily CO and NOx. A concurrent and accurate measurement of performance and emissions is an essential ingredient to the determination of turndown capability. Of particular challenge is the method by which turndown results that were measured at one set of ambient conditions can be accurately projected to a specific guarantee condition, or to a range of ambient conditions, for which turndown capabilities have been guaranteed. The turndown projection methodology needs to consider combustion physics, control system algorithms, and basic cycle thermodynamics. Recent advances in the integration of empirically tuned physics-based combustion models with control system models and the gas turbine thermodynamic simulation, has resulted in test procedures for use in the contractual demonstration of turndown capability. A discussion of these methods is presented, along with data showing the extent to which the methods have provided accurate and repeatable test results.

Marine Gas Turbine Performance Model for More Electric Ships

2011 ◽  
Author(s):  
George M. Koutsothanasis ◽  
Anestis I. Kalfas ◽  
Georgios Doulgeris
Keyword(s):  
Gas Turbine ◽  
Fuel Consumption ◽  
Diesel Engines ◽  
Gas Turbines ◽  
Electric Propulsion ◽  
Operating Conditions ◽  
Prime Mover ◽  
Creep Life ◽  
Hull Fouling ◽  
Turbine Performance

This paper presents the benefits of the more electric vessels powered by hybrid engines and investigates the suitability of a particular prime-mover for a specific ship type using a simulation environment which can approach the actual operating conditions. The performance of a mega yacht (70m), powered by two 4.5MW recuperated gas turbines is examined in different voyage scenarios. The analysis is accomplished for a variety of weather and hull fouling conditions using a marine gas turbine performance software which is constituted by six modules based on analytical methods. In the present study, the marine simulation model is used to predict the fuel consumption and emission levels for various conditions of sea state, ambient and sea temperatures and hull fouling profiles. In addition, using the aforementioned parameters, the variation of engine and propeller efficiency can be estimated. Finally, the software is coupled to a creep life prediction tool, able to calculate the consumption of creep life of the high pressure turbine blading for the predefined missions. The results of the performance analysis show that a mega yacht powered by gas turbines can have comparable fuel consumption with the same vessel powered by high speed Diesel engines in the range of 10MW. In such Integrated Full Electric Propulsion (IFEP) environment the gas turbine provides a comprehensive candidate as a prime mover, mainly due to its compactness being highly valued in such application and its eco-friendly operation. The simulation of different voyage cases shows that cleaning the hull of the vessel, the fuel consumption reduces up to 16%. The benefit of the clean hull becomes even greater when adverse weather condition is considered. Additionally, the specific mega yacht when powered by two 4.2MW Diesel engines has a cruising speed of 15 knots with an average fuel consumption of 10.5 [tonne/day]. The same ship powered by two 4.5MW gas turbines has a cruising speed of 22 knots which means that a journey can be completed 31.8% faster, which reduces impressively the total steaming time. However the gas turbine powered yacht consumes 9 [tonne/day] more fuel. Considering the above, Gas Turbine looks to be the only solution which fulfills the next generation sophisticated high powered ship engine requirements.

Numerical Assessment of SCAP: A Passive System for Preventing Thermoacoustic Oscillations in Gas Turbine Annular Combustors

2007 ◽  
Author(s):  
Stefano Tiribuzi
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Research Unit ◽  
Combined Cycle ◽  
Computational Time ◽  
Computational Domain ◽  
Ambient Conditions ◽  
Pressure Oscillations ◽  
Operation Conditions ◽  
Thermoacoustic Oscillations

ENEL operates a dozen combined cycle units whose V94.3A gas turbines are equipped with annular combustors. In such lean premixed gas turbines, particular operation conditions could trigger large pressure oscillations due to thermoacoustic instabilities. The ENEL Research unit is studying this phenomenon in order to find out methods which could avoid or mitigate such events. The use of effective numerical analysis techniques allowed us to investigate the realistic time evolution and behaviour of the acoustic fields associated with this phenomenon. KIEN, an in-house low diffusive URANS code capable of simulating 3D reactive flows, has been used in the Very Rough Grid approach. This approach permits the simulation, with a reasonable computational time, of quite long real transients with a computational domain extended over all the resonant volumes involved in the acoustic phenomenon. The V94.3A gas turbine model was set up with a full combustor 3D grid, going from the compressor outlet up to the turbine inlet, including both the annular plenum and the annular combustion chamber. The grid extends over the entire circular angle, including all the 24 premixed burners. Numerical runs were performed with the normal V94.3A combustor configuration, with input parameters set so as no oscillations develop in the standard ambient conditions. Wide pressure oscillations on the contrary are associated with the circumferential acoustic modes of the combustor, which have their onset and grow when winter ambient conditions are assumed. These results also confirmed that the sustaining mechanism is based on the equivalence ratio fluctuation of premix mixture and that plenum plays an important role in such mechanism. Based on these findings, a system for controlling the thermoacoustic oscillation has been conceived (Patent Pending), which acts on the plenum side of the combustor. This system, called SCAP (Segmentation of Combustor Annular Plenum), is based on the subdivision of the plenum annular volume by means of a few meridionally oriented walls. Repetition of KIEN runs with a SCAP configuration, in which a suitable number of segmentation walls were properly arranged in the annular plenum, demonstrated the effectiveness of this solution in preventing the development of wide thermoacoustic oscillations in the combustor.

Gas Turbine Exhaust Expansion Joints, Diverter and Damper Designs for the New Generation of Higher Temperature, High Efficiency Gas Turbines

1989 ◽  
Author(s):  
Lothar Bachmann ◽  
W. Fred Koch
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
High Efficiency ◽  
Combined Cycle ◽  
Operating Conditions ◽  
High Mass ◽  
Expansion Joints ◽  
Gas Turbine Exhaust ◽  
New Generation ◽  
Turbine Exhaust

The purpose of this paper is to update the industry on the evolutionary steps that have been taken to address higher requirements imposed on the new generation combined cycle gas turbine exhaust ducting expansion joints, diverter and damper systems. Since the more challenging applications are in the larger systems, we shall concentrate on sizes from nine (9) square meters up to forty (40) square meters in ducting cross sections. (Reference: General Electric Frame 5 through Frame 9 sizes.) Severe problems encountered in gas turbine applications for the subject equipment are mostly traceable to stress buckling caused by differential expansion of components, improper insulation, unsuitable or incompatible mechanical design of features, components or materials, or poor workmanship. Conventional power plant expansion joints or dampers are designed for entirely different operating conditions and should not be applied in gas turbine applications. The sharp transients during gas turbine start-up as well as the very high temperature and high mass-flow operation conditions require specific designs for gas turbine application.

Operating Experience With the Latest Upgrade of Alstom’s Sequential Combustion GT26 Gas Turbine

2010 ◽  
Author(s):  
Matthias Hiddeman ◽  
Peter Marx
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Operating Experience ◽  
Business Case ◽  
Combined Cycle ◽  
Fuel Gas ◽  
Power Generators ◽  
Additional Degree ◽  
Performance Improvements ◽  
Main Driver

The GT26 gas turbine provides an additional degree of flexibility as the engine operates at high efficiencies from part load to full load while still maintaining low NOx emissions. The sequential combustion, with the EV burner as the basis for this flexibility also extends to the ability to handle wide fluctuations in fuel gas compositions. Increased mass flow was the main driver for the latest GT26 upgrade, resulting in substantial performance improvements. In order to ensure high levels of reliability and availability Alstom followed their philosophy of evolutionary steps to continuously develop their gas turbines. A total of 47 engines of this upgrade of the GT26 gas turbine have been ordered worldwide to date (Status: January 2010) enhancing the business case of power generators by delivering superior operational and fuel flexibility and combined cycle efficiencies up to and beyond 59%.

Gas Turbine Part Load Performance Testing: Comparison of Test Methodologies

2008 ◽  
Author(s):  
Thomas P. Schmitt ◽  
Herve Clement
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Guide Vane ◽  
Performance Testing ◽  
Load Level ◽  
Combined Cycle ◽  
Inlet Guide Vane ◽  
Performance Guarantee ◽  
Part Load ◽  
Advantages And Disadvantages

Current trends in usage patterns of gas turbines in combined cycle applications indicate a substantial proportion of part load operation. Commensurate with the change in operating profile, there has been an increase in the propensity for part load performance guarantees. When a project is structured such that gas turbines are procured as equipment-only from the manufacturer, there is occasionally a gas turbine part load performance guarantee that coincides with the net plant combined cycle part load performance guarantee. There are several methods by which to accomplish part load gas turbine performance testing. One of the more common methods is to operate the gas turbine at the specified load value and construct correction curves at constant load. Another common method is to operate the gas turbine at a specified load percentage and construct correction curves at constant percent load. A third method is to operate the gas turbine at a selected load level that corresponds to a predetermined compressor inlet guide vane (IGV) angle. The IGV angle for this third method is the IGV angle that is needed to achieve the guaranteed load at the guaranteed boundary conditions. The third method requires correction curves constructed at constant IGV, just like base load correction curves. Each method of test and correction embodies a particular set of advantages and disadvantages. The results of an exploration into the advantages and disadvantages of the various performance testing and correction methods for part load performance testing of gas turbines are presented. Particular attention is given to estimates of the relative uncertainty for each method.

Heavy Duty Gas Turbine Simulation: Global Performances Estimation and Secondary Air System Modifications

2006 ◽  
Author(s):  
Carlo Carcasci ◽  
Bruno Facchini ◽  
Stefano Gori ◽  
Luca Bozzi ◽  
Stefano Traverso
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Cooling System ◽  
Energy System ◽  
Operating Conditions ◽  
Coupled Analysis ◽  
Ambient Conditions ◽  
Air System ◽  
Secondary Air ◽  
And Performance

This paper reviews a modular-structured program ESMS (Energy System Modular Simulation) for the simulation of air-cooled gas turbines cycles, including the calculation of the secondary air system. The program has been tested for the Ansaldo Energia gas turbine V94.3A, which is one of the more advanced models in the family Vx4.3A with a rated power of 270 MW. V94.3A cooling system has been modeled with SASAC (Secondary Air System Ansaldo Code), the Ansaldo code used to predict the structure of the flow through the internal air system. The objective of the work was to investigate the tuning of the analytical program on the basis of the data from design and performance codes in use at Ansaldo Energy Gas Turbine Department. The results, both at base load over different ambient conditions and in critical off-design operating points (full-speed-no-load and minimum-load), have been compared with APC (Ansaldo Performance Code) and confirmed by field data. The coupled analysis of cycle and cooling network shows interesting evaluations for components life estimation and reliability during off-design operating conditions.

Numerical and Experimental Investigation of Secondary Flows and Influence of Air System Design on Heavy-Duty Gas Turbine Performance

2012 ◽  
Author(s):  
Luca Bozzi ◽  
Enrico D’angelo
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Engine Performance ◽  
Combined Cycle ◽  
Secondary Flows ◽  
Operating Conditions ◽  
Heavy Duty ◽  
Turbine Performance ◽  
Air System ◽  
Secondary Air

High turn-down operating of heavy-duty gas turbines in modern Combined Cycle Plants requires a highly efficient secondary air system to ensure the proper supply of cooling and sealing air. Thus, accurate performance prediction of secondary flows in the complete range of operating conditions is crucial. The paper gives an overview of the secondary air system of Ansaldo F-class AEx4.3A gas turbines. Focus of the work is a procedure to calculate the cooling flows, which allows investigating both the interaction between cooled rows and additional secondary flows (sealing and leakage air) and the influence on gas turbine performance. The procedure is based on a fluid-network solver modelling the engine secondary air system. Parametric curves implemented into the network model give the consumption of cooling air of blades and vanes. Performances of blade cooling systems based on different cooling technology are presented. Variations of secondary air flows in function of load and/or ambient conditions are discussed and justified. The effect of secondary air reduction is investigated in details showing the relationship between the position, along the gas path, of the upgrade and the increasing of engine performance. In particular, a section of the paper describes the application of a consistent and straightforward technique, based on an exergy analysis, to estimate the effect of major modifications to the air system on overall engine performance. A set of models for the different factors of cooling loss is presented and sample calculations are used to illustrate the splitting and magnitude of losses. Field data, referred to AE64.3A gas turbine, are used to calibrate the correlation method and to enhance the structure of the lumped-parameters network models.

Update on Mitsubishi G Series Gas Turbines With Over 78,000 Hours Fleet Operation

2003 ◽  
Author(s):  
V. Kallianpur ◽  
D. Stacy ◽  
Y. Fukuizumi ◽  
H. Arimura ◽  
S. Uchida
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Power Plants ◽  
Operating Time ◽  
Operating Experience ◽  
Combined Cycle ◽  
Air Cooling ◽  
Commercial Operation ◽  
Advanced Stages ◽  
Steam Cooling

Seven G gas turbines from Mitsubishi are in commercial operational at various combined cycle power plants since the first Mitsubishi G gas turbine was inroduced in 1997. The combined operating time on the fleet exceeds over 78,000 actual hours. Additional power plants using Mitsubishi G-series gas turbines are in advanced stages of commissioning in the U.S.A., and are expected to be in commercial operation in 2003. This paper describes operating experience of the Mitsubishi G-series gas turbines, which apply steam-cooling instead of air-cooling to cool the combustor liners. The paper discusses design enhancements that were made to the lead M501G gas turbine at Mitsubishi’s in-house combined cycle power plant facility. It also addresses the effectiveness of those enhancements from the standpoint of hot parts durability and reliability at other power plants that are in commercial operation using Mitsubishi G gas turbines.

Operating Experience in Refinery Application of the 13MW-Class Heavy Duty MF-111 Gas Turbine Engine

1990 ◽  
Author(s):  
J. Masada ◽  
I. Fukue
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Operating Experience ◽  
Combined Cycle ◽  
Outlet Temperature ◽  
Heavy Duty ◽  
Turbine Engine ◽  
Industrial Gas Turbines ◽  
Heavy Duty Gas Turbine ◽  
Temperature Levels

A new, 13MW class, heavy duty gas turbine, the “MF-111” was developed for use as a prime mover for cogeneration, combined cycle and repowering applications. The use of such equipment in refineries presents special challenges as regards the combustion of nonstandard fuels, tolerance of industrial environments, and accomodation of site-specific design requirements. Such circumstances add substantially to the tasks of proving and adjusting the design of a new gas turbine, meeting stringent emissions requirements and introducing to the world of industrial gas turbines the benefits of F-class (1250°C burner outlet temperature) levels of thermodynamic performance. This paper describes how these challenges have successfully been met during the three calendar years and ten machine-years of MF-111 refinery-application experience accumulated to-late.

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