Off-Design Performance Investigation of a Low Calorific Value Gas Fired Generic Type Single-Shaft Gas Turbine

2007 ◽  
Author(s):  
Raik C. Orbay ◽  
Magnus Genrup ◽  
Pontus Eriksson ◽  
Jens Klingmann
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Pressure Ratio ◽  
Calorific Value ◽  
Working Fluid ◽  
Inlet Temperature ◽  
Flammability Limits ◽  
Generic Type ◽  
Wobbe Index ◽  
The Impact

When low calorific value gases are fired, the performance and stability of gas turbines may deteriorate due to a large amount of inert ballast and changes in working fluid properties. Since it is rather rare to have custom-built gas turbines for low Lower Heating Value (LHV) operation, the engine will be forced to operate outside its design envelope. This, in turn, poses limitations to usable fuel choices. Typical restraints are decrease in Wobbe-index and surge- and flutter-margins for turbomachinery. In this study, an advanced performance deck has been used to quantify the impact of firing low-LHV gases in a generic type gas turbine. A single-shaft gas turbine characterized by a compressor and an expander map is considered. Emphasis has been put on predicting the off-design behavior. The combustor is discussed and related to previous experiments which include investigation of flammability limits, Wobbe-index, flame position, etc. The computations show that at constant turbine inlet temperature (TIT), the shaft power and the pressure ratio will increase, however the surge margin will decrease. Possible design changes in the component level are also discussed. Aerodynamic issues (and necessary modifications) that can pose severe limitations on the gas turbine compressor- and turbine sections are discussed. Typical methods for axial turbine capacity adjustment are presented and discussed.

Off-Design Performance Investigation of a Low Calorific Value Gas Fired Generic-Type Single-Shaft Gas Turbine

2008 ◽  
Vol 130 (3) ◽  
Author(s):  
Raik C. Orbay ◽  
Magnus Genrup ◽  
Pontus Eriksson ◽  
Jens Klingmann
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Pressure Ratio ◽  
Calorific Value ◽  
Working Fluid ◽  
Inlet Temperature ◽  
Flammability Limits ◽  
Generic Type ◽  
Wobbe Index ◽  
The Impact

When low calorific value gases are fired, the performance and stability of gas turbines may deteriorate due to a large amount of inertballast and changes in working fluid properties. Since it is rather rare to have custom-built gas turbines for low lower heating value (LHV) operation, the engine will be forced to operate outside its design envelope. This, in turn, poses limitations to usable fuel choices. Typical restraints are decrease in Wobbe index and surge and flutter margins for turbomachinery. In this study, an advanced performance deck has been used to quantify the impact of firing low-LHV gases in a generic-type recuperated as well as unrecuperated gas turbine. A single-shaft gas turbine characterized by a compressor and an expander map is considered. Emphasis has been put on predicting the off-design behavior. The combustor is discussed and related to previous experiments that include investigation of flammability limits, Wobbe index, flame position, etc. The computations show that at constant turbine inlet temperature, the shaft power and the pressure ratio will increase; however, the surge margin will decrease. Possible design changes in the component level are also discussed. Aerodynamic issues (and necessary modifications) that can pose severe limitations on the gas turbine compressor and turbine sections are discussed. Typical methods for axial turbine capacity adjustment are presented and discussed.

Thermodynamic Evaluation of Gas Turbine Cogeneration Cycles: Part I—Heat Balance Method Analysis

1987 ◽  
Vol 109 (1) ◽  
pp. 1-7 ◽  
Author(s):  
I. G. Rice
Keyword(s):  
Gas Turbine ◽  
Heat Balance ◽  
Gas Turbines ◽  
Heat Recovery ◽  
Pressure Ratio ◽  
Turbine Rotor ◽  
Balance Method ◽  
Inlet Temperature ◽  
Thermodynamic Evaluation ◽  
Exhaust Temperature

This paper presents a heat balance method of evaluating various open-cycle gas turbines and heat recovery systems based on the first law of thermodynamics. A useful graphic solution is presented that can be readily applied to various gas turbine cogeneration configurations. An analysis of seven commercially available gas turbines is made showing the effect of pressure ratio, exhaust temperature, intercooling, regeneration, and turbine rotor inlet temperature in regard to power output, heat recovery, and overall cycle efficiency. The method presented can be readily programmed in a computer, for any given gaseous or liquid fuel, to yield accurate evaluations. An X–Y plotter can be utilized to present the results.

Parametric analysis of a gas turbine cycle coupled to a Brayton refrigeration cycle

2009 ◽  
Vol 223 (5) ◽  
pp. 497-503 ◽  
Author(s):  
L Chen ◽  
W Zhang ◽  
F Sun
Keyword(s):  
Gas Turbine ◽  
Power Efficiency ◽  
Pressure Ratio ◽  
Maximum Efficiency ◽  
Working Fluid ◽  
Inlet Temperature ◽  
Refrigeration Cycle ◽  
Fluid Temperature ◽  
Optimal Power ◽  
Brayton Refrigeration Cycle

Performance analysis and optimization of an endoreversible Brayton cycle coupled to a Brayton refrigeration cycle has been performed using finite-time thermodynamics. The analy-tical formulae are derived with respect to power, efficiency, optimal extracted pressure ratio of air refrigeration cycle corresponding to optimal power, optimal power and the corresponding efficiency. The influences of various parameters on the cycle performances are analysed by numerical examples. The results show that there exists one optimal pressure ratio of the compressor corresponding to maximum power and another optimal pressure ratio of the compressor corresponding to maximum efficiency; the compressor inlet temperature is reduced by mixing the chilled working fluid from the Brayton refrigeration cycle and the main intake working fluid streams; the intake working fluid temperature could be controlled even below the temperature of the heat sink and the gas turbine performance can be improved.

The Impact of Atmospheric Conditions on Gas Turbine Performance

1990 ◽  
Vol 112 (4) ◽  
pp. 590-596 ◽  
Author(s):  
A. A. El Hadik
Keyword(s):  
Relative Humidity ◽  
Ambient Temperature ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Arabian Gulf ◽  
Inlet Temperature ◽  
Atmospheric Conditions ◽  
Design Factor ◽  
Turbine Performance ◽  
The Impact

In a hot summer climate, as in Kuwait and other Arabian Gulf countries, the performance of a gas turbine deteriorates drastically during the high-temperature hours (up to 60°C in Kuwait). Power demand is the highest at these times. This necessitates an increase in installed gas turbine capacities to balance this deterioration. Gas turbines users are becoming aware of this problem as they depend more on gas turbines to satisfy their power needs and process heat for desalination due to the recent technical and economical development of gas turbines. This paper is devoted to studying the impact of atmospheric conditions, such as ambient temperature, pressure, and relative humidity on gas turbine performance. The reason for considering air pressures different from standard atmospheric pressure at the compressor inlet is the variation of this pressure with altitude. The results of this study can be generalized to include the cases of flights at high altitudes. A fully interactive computer program based on the derived governing equations is developed. The effects of typical variations of atmospheric conditions on power output and efficiency are considered. These include ambient temperature (range from −20 to 60°C), altitude (range from zero to 2000 m above sea level), and relative humidity (range from zero to 100 percent). The thermal efficiency and specific net work of a gas turbine were calculated at different values of maximum turbine inlet temperature (TIT) and variable environmental conditions. The value of TIT is a design factor that depends on the material specifications and the fuel/air ratio. Typical operating values of TIT in modern gas turbines were chosen for this study: 1000, 1200, 1400, and 1600 K. Both partial and full loads were considered in the analysis. Finally the calculated results were compared with actual gas turbine data supplied by manufacturers.

scholarly journals Combustion of LCV Coal Derived Fuel Gas for High Temperature, Low Emissions Gas Turbines in the British Coal Topping Cycle

1991 ◽  
Author(s):  
G. J. Kelsall ◽  
M. A. Smith ◽  
H. Todd ◽  
M. J. Burrows
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Calorific Value ◽  
Pollutant Emissions ◽  
Inlet Temperature ◽  
Outlet Temperature ◽  
Combustion System ◽  
Fuel Gas ◽  
Gas Turbine Combustion ◽  
Topping Cycle

Advanced coal based power generation systems such as the British Coal Topping Cycle offer the potential for high efficiency electricity generation with minimum environmental impact. An important component of the Topping Cycle programme is the development of a gas turbine combustion system to burn low calorific value (3.5–4.0 MJ/m3 wet gross) coal derived fuel gas, at a turbine inlet temperature of 1260°C, with minimum pollutant emissions. The paper gives an overview of the British Coal approach to the provision of a gas turbine combustion system for the British Coal Topping Cycle, which includes both experimental and modelling aspects. The first phase of this programme is described, including the design and operation of a low-NOx turbine combustor, operating at an outlet temperature of 1360°C and burning a synthetic low calorific value (LCV) fuel gas, containing 0 to 1000 ppmv of ammonia. Test results up to a pressure of 8 bar are presented and the requirements for further combustor development outlined.

scholarly journals 100s and 1000s Mw Open and Semi-Closed Cycle Gas Turbines for Base and Peak Operation

1974 ◽  
Author(s):  
V. V. Uvarov ◽  
V. S. Beknev ◽  
E. A. Manushin
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Pressure Ratio ◽  
Simple Cycle ◽  
Inlet Temperature ◽  
Closed Cycle ◽  
Turbine Inlet Temperature ◽  
Unit Capacity ◽  
Temperature And Pressure ◽  
Different Levels

There are two different approaches to develop the gas turbines for power. One can get some megawatts by simple cycle or by more complex cycle units. Both units require very different levels of turbine inlet temperature and pressure ratio for the same unit capacity. Both approaches are discussed. These two approaches lead to different size and efficiencies of gas turbine units for power. Some features of the designing problems of such units are discussed.

Conceptual Investigation of a Small Reheat Gas Turbine System

2003 ◽  
Author(s):  
Norihiko Iki ◽  
Hirohide Furutani ◽  
Sanyo Takahashi
Keyword(s):  
Gas Turbine ◽  
Thermal Efficiency ◽  
Gas Turbines ◽  
Water Injection ◽  
Working Fluid ◽  
Inlet Temperature ◽  
Micro Gas Turbine ◽  
Thermal Generator ◽  
Process Simulator ◽  
Characteristic Component

The mirror gas turbine proposed by Tsujikawa and Fujii extends the applications of turbo machinery. The characteristic component of a mirror gas turbine is a thermal generator, which is a kind of “inverted Brayton cycle”. The operating sequence of the thermal generator is reverse that of an ordinary gas turbine, namely, the hot working fluid is first expanded, and then cooled, compressed, and finally exhausted. In this work, we investigated the theoretical feasibility of inserting a thermal generator to a small reheat gas turbine of 30–100kW classes. Using process simulator software, we calculated and compared the thermal efficiency of this reheat gas turbine to that of a micro gas turbine under several conditions, turbine inlet temperature. This comparison showed that the performances of the both gas turbines are significantly influenced by the performance of the heat exchanger used for the recuperator. The efficiency of the micro gas turbine is also improved by using water injection into the compressor to cool the inlet gas. The resulting thermal efficiency of this reheat gas turbine is about 7% higher than that of a micro gas turbine with the same power unit.

Selection of Gas Turbine With Minimum Flue Gas Emission

2007 ◽  
Author(s):  
P. Esna Ashari ◽  
V. Nayyeri ◽  
K. Sarabchee
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Power Plants ◽  
Fossil Fuels ◽  
Pressure Ratio ◽  
Inlet Temperature ◽  
Effective Parameters ◽  
Combustion Chambers ◽  
Optimum Pressure ◽  
Oil Refineries

Many factories in industry such as petrochemical plants, oil refineries and power plants need heat and power to support their process. This demand can be provided by a combined heat and power cycle (CHP) in the factory site. Some factories use gas turbine cycle to provide heat and power. Emissions from gas turbines, produced by burning fossil fuels in the combustion chambers, have important effects on air pollution. This is a significant problem in many developed and developing countries. Parameters such as inlet temperature and pressure ratio are the most effective parameters in gas turbine emission. By selecting an appropriate gas turbine, emission could be reduced to some extent. Further studies indicate that there is an optimum pressure ratio, which minimizes emissions.

Increasing Diagnostic Effectiveness by Inclusion of Fuel Composition and Water Injection Effects

2002 ◽  
Author(s):  
K. Mathioudakis ◽  
N. Aretakis ◽  
A. Tsalavoutas
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Water Injection ◽  
Diagnostic Technique ◽  
Diagnostic Methods ◽  
Working Fluid ◽  
Fluid Properties ◽  
Industrial Gas Turbines ◽  
The Impact ◽  
Engine Condition

The paper presents an analysis of the effect of changing the fuel on the performance of industrial gas turbines and examines the impact of such a change on methods used for engine condition assessment and fault diagnostics. A similar analysis is presented for the effects of water injection in the combustion chamber (which is usually done for reducing NOx emissions). First, the way of incorporating the effect of fuel changes and water injection into a computer model of gas turbine performance is described. The approach employed is based on the change of (a) working fluid properties, (b) turbomachinery components performance. The model is then used to derive parameters indicative of the “health” of a gas turbine and thus diagnose the presence of deterioration or faults. The impact of ignoring the presence of an altered fuel or injected water is shown to be of a magnitude that would render a diagnostic technique that does not incorporate these effects ineffective. On the other hand, employing the appropriate physical modeling makes the diagnostic methods robust and insensitive to such changes, being thus able to provide useful diagnostic information continuously during the use of a gas turbine.

scholarly journals Development of a High Pressure Ratio Centrifugal Compressor for 300kW-Class Ceramic Gas Turbine

1997 ◽  
Author(s):  
T. Sakai ◽  
Y. Tohbe ◽  
T. Fujii ◽  
T. Tatsumi
Keyword(s):  
Research And Development ◽  
Gas Turbine ◽  
Gas Turbines ◽  
High Efficiency ◽  
Pressure Ratio ◽  
Flow Distribution ◽  
Leading Edge ◽  
Inlet Temperature ◽  
Angle Distribution ◽  
Gas Generator

Research and development of ceramic gas turbines (CGT), which is promoted by the Japanese Ministry of International Trade and Industry (MITI), was started in 1988. The target of the CGT project is development of a 300kW-class ceramic gas turbine with a 42 % thermal efficiency and a turbine inlet temperature (TIT) of 1350°C. Two types of CGT engines are developed in this project. One of the CGT engines, which is called CGT302, is a recuperated two-shaft gas turbine with a compressor, a gas-generator turbine, and a power turbine for cogeneration. In this paper, we describe the research and development of a compressor for the CGT302. Specification of this compressor is 0.89 kg/sec air flow rate and 8:1 pressure ratio. The intermediary target efficiency is 78% and the final target efficiency is 82%, which is the highest level in email centrifugal compressors like this one. We measured impeller inlet and exit flow distribution using three-hole yaw probes which were traversed from the shroud to the hub. Based on the measurement of the impeller exit flow, diffusers with a leading edge angle distribution adjusted to the inflow angle were designed and manufactured. Using this diffuser, we were able to attain a high efficiency (8:1 pressure ratio and 78% adiabatic efficiency).

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