Thermodynamic Design Considerations for Steam-Injected Gas Turbines

1993 ◽  
Author(s):  
Peter D. Noymer ◽  
David Gordon Wilson
Keyword(s):  
Gas Turbine ◽  
Power Output ◽  
Gas Turbines ◽  
Steam Injection ◽  
Point Of View ◽  
Inlet Temperature ◽  
Design Point ◽  
Attractive Option ◽  
Overall Efficiency ◽  
Net Power Output

Steam injection in gas turbines (steam raised from the energy of the exhaust and injected into one or more of the turbine stages) is an attractive option for cogeneration applications. From a thermodynamic point of view, however, there is little information available about methods for optimizing the use of the steam for injection into a gas turbine. A computer model for an aeroderivative gas turbine is used to analyze the effect of steam injection on net power output and overall efficiency. The effects of varying the quantity of steam injected, the stations at which the steam is injected, and the temperature of the steam that is injected are assessed on a normalized basis, with the turbine-inlet temperature maintained from the simple-cycle design point. The energy balance between the exhaust of the gas turbine and the flow of steam to be injected is the final constraint in selecting a steam-injected design point to maximize performance. For the engine in this study, increases of over 64% in net power output and 23% in overall efficiency can be achieved with roughly 16% steam/inlet air by mass, which represents all of the steam that can be produced by the exhaust stream for the given conditions.

Genetic Optimization of Steam Injected Gas Turbine Power Plants

2002 ◽  
Author(s):  
Ibrahim Sinan Akmandor ◽  
O¨zhan O¨ksu¨z ◽  
Sec¸kin Go¨kaltun ◽  
Melih Han Bilgin
Keyword(s):  
Gas Turbine ◽  
Power Output ◽  
Thermal Efficiency ◽  
Gas Turbines ◽  
Power Plants ◽  
Pressure Ratio ◽  
Steam Injection ◽  
Combined Cycle ◽  
Inlet Temperature ◽  
Compressor Pressure Ratio

A new methodology is developed to find the optimal steam injection levels in simple and combined cycle gas turbine power plants. When steam injection process is being applied to simple cycle gas turbines, it is shown to offer many benefits, including increased power output and efficiency as well as reduced exhaust emissions. For combined cycle power plants, steam injection in the gas turbine, significantly decreases the amount of flow and energy through the steam turbine and the overall power output of the combined cycle is decreased. This study focuses on finding the maximum power output and efficiency of steam injected simple and combined cycle gas turbines. For that purpose, the thermodynamic cycle analysis and a genetic algorithm are linked within an automated design loop. The multi-parameter objective function is either based on the power output or on the overall thermal efficiency. NOx levels have also been taken into account in a third objective function denoted as steam injection effectiveness. The calculations are done for a wide range of parameters such as compressor pressure ratio, turbine inlet temperature, air and steam mass flow rates. Firstly, 6 widely used simple and combined cycle power plants performance are used as test cases for thermodynamic cycle validation. Secondly, gas turbine main parameters are modified to yield the maximum generator power and thermal efficiency. Finally, the effects of uniform crossover, creep mutation, different random number seeds, population size and the number of children per pair of parents on the performance of the genetic algorithm are studied. Parametric analyses show that application of high turbine inlet temperature, high air mass flow rate and no steam injection lead to high power and high combined cycle thermal efficiency. On the contrary, when NOx reduction is desired, steam injection is necessary. For simple cycle, almost full amount of steam injection is required to increase power and efficiency as well as to reduce NOx. Moreover, it is found that the compressor pressure ratio for high power output is significantly lower than the compressor pressure ratio that drives the high thermal efficiency.

A Novel Concept for Combined Heat and Cooling in Humid Gas Turbine Cycles

2007 ◽  
Author(s):  
Alessandro Corradetti ◽  
Umberto Desideri ◽  
Ashok D. Rao
Keyword(s):  
Water Vapor ◽  
Gas Turbine ◽  
Power Output ◽  
Gas Turbines ◽  
Operating Conditions ◽  
Sensitivity Analyses ◽  
Inlet Temperature ◽  
Electrical Efficiency ◽  
Novel Concept ◽  
Net Power Output

Various gas turbine cycles are known where water is introduced as a liquid or as a vapor into the combustor of the gas turbine. Such cycles include the Humid Air Turbine (HAT) cycle, the Steam Injected (STIG) cycle, and the Regenerated Water Injected gas turbine cycle (RWI). The effect of water vapor is the increasing of net power output and the reduction of NOx formation within the combustor. However the net increase in power output is limited in commercial models of gas turbines, because a large addition of water vapor leads to the mismatch between the compressor and the turbine. In this paper a possible method to solve this problem is proposed: it is based on a novel concept for combining refrigeration and power production in humid gas turbine cycles. In the proposed system a fraction of the air at compressor discharge is extracted, cooled to nearly ambient temperature, dried and expanded in a turbine. At turbine outlet the air is at a very low temperature and can be used for providing refrigeration. A thermodynamic analysis has been carried out to investigate the performance of the system in HAT, STIG and RWI cycles for different operating conditions representing the state of art of commercial gas turbines. In particular the pressure ratio and the turbine inlet temperature have been respectively varied in the range 7–45 and 900–1500°C. Sensitivity analyses have been performed to assess how the amounts of extracted air and injected steam affect the net power output, the electrical efficiency and the cooling. The results show that cryogenic temperatures (lower than −100°C) for refrigeration can be achieved in combination with very high electrical efficiency (over 40%, typical of humid gas turbine cycles).

scholarly journals A Test Rig for the Realization of Water Recovery in a Steam-Injected Gas Turbine

1996 ◽  
Author(s):  
Xueyou Wen ◽  
Jiguo Zou ◽  
Zheng Fu ◽  
Shikang Yu ◽  
Lingbo Li
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Steam Injection ◽  
Water Recovery ◽  
Test Rig ◽  
Design Point ◽  
Test Conditions ◽  
Demineralized Water ◽  
Spiral Plate ◽  
Industrial Gas Turbine

Steam-injected gas turbines have a multitude of advantages, but they suffer from the inability to recover precious demineralized water. The present paper describes the test conditions and results of steam injection along with an attempt to achieve water recovery, which were obtained through a series of tests conducted on a S1A-02 small-sized industrial gas turbine. A water recovery device incorporating a compact finned spiral plate cooling condenser equipped with filter screens has been designed for the said gas turbine and a 100% water recovery (based on the design point) was attained.

scholarly journals Implementation of Adaptive Neuro-fuzzy Model to Optimize Operational Process of Multiconfiguration Gas-Turbines

2020 ◽  
Vol 2020 ◽  
pp. 1-17
Author(s):  
Chao Deng ◽  
Ahmed N. Abdalla ◽  
Thamir K. Ibrahim ◽  
MingXin Jiang ◽  
Ahmed T. Al-Sammarraie ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Power Output ◽  
Gas Turbines ◽  
Pressure Ratio ◽  
Operating Conditions ◽  
Inlet Temperature ◽  
Turbine Inlet Temperature ◽  
Anfis Model ◽  
Neuro Fuzzy ◽  
Compressor Efficiency

In this article, the adaptive neuro-fuzzy inference system (ANFIS) and multiconfiguration gas-turbines are used to predict the optimal gas-turbine operating parameters. The principle formulations of gas-turbine configurations with various operating conditions are introduced in detail. The effects of different parameters have been analyzed to select the optimum gas-turbine configuration. The adopted ANFIS model has five inputs, namely, isentropic turbine efficiency (Teff), isentropic compressor efficiency (Ceff), ambient temperature (T1), pressure ratio (rp), and turbine inlet temperature (TIT), as well as three outputs, fuel consumption, power output, and thermal efficiency. Both actual reported information, from Baiji Gas-Turbines of Iraq, and simulated data were utilized with the ANFIS model. The results show that, at an isentropic compressor efficiency of 100% and turbine inlet temperature of 1900 K, the peak thermal efficiency amounts to 63% and 375 MW of power resulted, which was the peak value of the power output. Furthermore, at an isentropic compressor efficiency of 100% and a pressure ratio of 30, a peak specific fuel consumption amount of 0.033 kg/kWh was obtained. The predicted results reveal that the proposed model determines the operating conditions that strongly influence the performance of the gas-turbine. In addition, the predicted results of the simulated regenerative gas-turbine (RGT) and ANFIS model were satisfactory compared to that of the foregoing Baiji Gas-Turbines.

Aero-Thermodynamic Simulation of a Double-Shaft Industrial Evaporative Gas Turbine

2000 ◽  
Author(s):  
S. M. Camporeale ◽  
B. Fortunato
Keyword(s):  
Ambient Temperature ◽  
Gas Turbine ◽  
Power Output ◽  
Gas Turbines ◽  
Thermodynamic Simulation ◽  
Inlet Temperature ◽  
Part Load ◽  
Design Performance ◽  
Water Rate ◽  
Advanced Cycles

A modeling study has been carried out in order to determine the behavior of evaporative industrial gas turbines power plants at part-load and for varying ambient temperature. On-design and off-design performance have been analyzed by means of a computational program developed for the analysis of advanced cycles. In order to verify the mathematical model and to evaluate the characteristics of up-to-date gas turbine technology, an industrial engine, presently available on the market, has been simulated. A double-shaft gas turbine for power generation has been considered. On-design performance and ratings vs. ambient temperature have been evaluated, with good accordance. It is assumed that, in order to realize a Recuperated Water Injected (RWI) cycle, the industrial gas turbine could be modified, maintaining substantially unchanged the compression system and modifying the turbine blades. The thermodynamic analysis of the cycle has been carried out in order to determine efficiency and power output as a function of the amount of water addition. The RWI cycle gas turbine has been designed and the characteristic maps of the two new turbines have been evaluated. The regulation is performed by means of the simultaneous manipulation of fuel flow rate, water rate, and position of the free turbine nozzle guide vanes (NGV). The regulation criteria, the interaction among the input variables, the safety of the operations (max. turbine inlet temperature, surge limits) and the optimization of the part-load efficiency, are examined and discussed. Ratings as a function of the ambient temperature are examined. The possibility to manipulate the water rate and the position of the NGV in order to provide high efficiency and power output, even on hot days, has been examined. The paper shows that maintaining constant the temperature at the power turbine exit, ratings decrease of 17% in power and 5% in efficiency.

Advances in the Development of a Micro-Gas Turbine Engine at Onera

2013 ◽  
Author(s):  
O. Dessornes ◽  
S. Landais ◽  
R. Valle ◽  
A. Fourmaux ◽  
S. Burguburu ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Pressure Ratio ◽  
Gas Turbine Engine ◽  
Inlet Temperature ◽  
Portable Devices ◽  
Good Efficiency ◽  
Turbine Engine ◽  
Micro Gas Turbine ◽  
Overall Efficiency

To reduce the size and weight of power generation machines for portable devices, several systems to replace the currently used heavy batteries are being investigated worldwide. As micro gas turbines are expected to offer the highest power density, several research groups launched programs to develop ultra micro gas turbines: IHI firm (Japan), PowerMEMS Consortium (Belgium). At Onera, a research program called DecaWatt is under development in order to realize a demonstrator of a micro gas turbine engine in the 50 to 100 Watts electrical power range. A single-stage gas turbine is currently being studied. First of all, a calculation of the overall efficiency of the micro gas turbine engine has been carried out according to the pressure ratio, the turbine inlet temperature and the compressor and turbine efficiencies. With realistic hypotheses, we could obtain an overall efficiency of about 5% to 10% which leads to around 200 W/kg when taking into account the mass of the micro gas turbine engine, its electronics, fuel and packaging. Moreover, the specific energy could be in the range 300 to 600 Wh/kg which exceeds largely the performance of secondary batteries. To develop such a micro gas turbine engine, experimental and computational work focused on: • a 10 mm in diameter centrifugal compressor, with the objective to obtain a pressure ratio of about 2.5 • a radial inflow turbine • journal and thrust gas bearings (lobe bearings and spiral grooves) and their manufacturing • a small combustor working with hydrogen or hydrocarbon gaseous fuel (propane) • a high rotation speed micro-generator • the choice of materials Components of this tiny engine were tested prior to the test with all the parts assembled together. Tests of the generator at 700,000 rpm showed a very good efficiency of this component. In the same way, compressor testing has been performed up to 500,000 rpm and has shown that the nominal compression rate at the 840,000 rpm nominal speed should be nearly reached.

Power Output Increase due to Decreasing Gas Turbine Inlet Temperature by Mist Atomization

2011 ◽  
Author(s):  
Yukiko Agata ◽  
Shinichi Akabayashi ◽  
Shinya Ishikawa ◽  
Yuji Matsumura
Keyword(s):  
Power Plant ◽  
Gas Turbine ◽  
Power Output ◽  
Gas Turbines ◽  
Thermal Power ◽  
Field Tests ◽  
Flow Path ◽  
Inlet Temperature ◽  
Turbine Inlet Temperature ◽  
Turbine Inlet

Decreases in inlet mass flow due to rises in ambient temperature during the summer lead to a decrease in the power output of gas turbines. In order to recover lost output, this study employed a mist atomization system using efficient spray nozzles, developed mainly as a technology for urban heat-island mitigation, installing the system in an inlet air flow path of a gas turbine at Higashi-Niigata thermal power station No.4 train, a commercial plant. The nozzles can efficiently decrease inlet air temperature of gas turbines because of their minute atomized mist size and highly-efficient evaporation properties. A flow path in the upstream of the inlet filter was used for mist evaporation by the system. This path is unique to the power plant, and is intended to prevent snow particles from direct entry. Model and field tests to confirm safe and effective operation of the system developed were performed in order to address possible concerns associated with the introduction of this system. As a basic consideration, wind tunnel experiments using nozzles were performed. Through the experiments, the most suitable nozzles were chosen, and effectiveness of the mist atomization was evaluated. The basic specifications of the system were determined from the evaluation results. At the same time, flow-field in the inlet air channel of the intended gas turbine was analyzed, and positioning of the atomization devices optimized. The mist atomization system that was developed was installed in a gas turbine at the power plant. To prevent excessive atomization from possibly causing erosion, a target value of 95% humidity at the compressor inlet was set, and a thermo-hygrometer was installed downstream of the inlet silencer to monitor humidity. As a result of the operation, no signs of erosion were detected in a major inspection conducted about one year following the introduction of the system. Another concern had to do with immediate changes in the state of the gas turbine due to mist atomization stoppages. To evaluate effects of the stoppages, field tests in the plant were performed, resulting in no significant changes in turbine inlet temperature and exhaust gas temperature. Combustion pressure oscillations was also not observed. From these results, it has been confirmed that the system can be operated safely. After activating the atomization system, inlet temperature decreased by up to about 7.5 degrees Celsius and power output increased by up to 13 MW in the gas turbine.

Augmentation of Gas Turbine Power Output by Steam Injection

2001 ◽  
Author(s):  
August C. Fischer ◽  
Hans Ulrich Frutschi ◽  
Hermann Haselbacher
Keyword(s):  
Gas Turbine ◽  
Mass Flow ◽  
Power Output ◽  
Thermal Efficiency ◽  
Gas Turbines ◽  
Steam Injection ◽  
Simultaneous Increase ◽  
Exhaust Heat ◽  
Entire Amount ◽  
The Impact

Steam injection into the combustion chambers of gas turbines (GT) increases their power output. Additionally, the thermal efficiency can be raised, if steam is generated by exhaust heat. The types of steam injected gas turbines (STIG) are distinguished according to the kind of limit to the amount of steam that can be injected. A gas turbine is called partial STIG, if it cannot utilize the total amount of steam that could be generated by the gas turbine exhaust heat. The limit is given by the flow capacity of the turbine. If, on the other hand, the gas turbine is sized such that the entire amount of steam producible can be utilized, it is called full STIG. Three different partial STIG cooling models were selected to analyze the power output, the efficiency and the impact on two important components. Since the differences in the results for the three cycles are marginal, the following conclusion can be briefly summarized: Compressor surge turned out to be the strongest limit for overloading the gas turbine. At the point of maximum overload — where safe operation is still guaranteed — the steam mass flow amounts to one tenth of the nominal compressor air mass flow. At this operating point, the power output can be raised by more than 30% with a simultaneous increase in efficiency. Based on the gas turbine configurations used for the partial STIGs, the preliminary designs of two full STIG cycles have been developed. However, for full STIG operation by injection of the total amount of steam producible, either the compressor or the turbines of the original gas turbine have to be modified. In this case, the steam flow exceeding that required for cooling has to be injected into the compressed air in front of the combustor. Depending on whether the compressor is scaled down or the turbines are scaled up, the power output of full STIGs is 30 to 135% higher than that of the original gas turbine. The gross thermal efficiency is about 50.5.%.

Parametric Study of Inlet Cooling With Varied COP on Gas Turbine Performance

2014 ◽  
Author(s):  
Maryam Besharati-Givi ◽  
Xianchang Li
Keyword(s):  
Ambient Temperature ◽  
Gas Turbine ◽  
Power Output ◽  
Gas Turbines ◽  
High Efficiency ◽  
Cooling System ◽  
Coefficient Of Performance ◽  
Inlet Temperature ◽  
Turbine Performance ◽  
Compressor Inlet

Gas turbines play an important role in power generation, and it is therefore desired to operate gas turbines with high efficiency and power output. One of the most influential parameters on the performance of a gas turbine is the ambient condition. It is known that inlet cooling can improve the gas turbine performance, especially when the ambient temperature is high. This study examines the effect of inlet cooling with different operating parameters such as compressor inlet temperature, turbine inlet temperature, air fuel ratio, and pressure ratio. Furthermore, the coefficient of performance (COP) of the cooling system is considered a function of the ambient temperature. Aspen Plus software is used to simulate the system under a steady-flow condition. The results indicate that the cooling of the compressor inlet air can substantially improve the power output as well as the overall efficiency of system. More importantly, there exists an optimal temperature at which the inlet cooling should be operated to achieve the highest efficiency.

Simulation of Producer Gas Fired Power Plants With Inlet Fog Cooling and Steam Injection

2006 ◽  
Author(s):  
Mun Roy Yap ◽  
Ting Wang
Keyword(s):  
Natural Gas ◽  
Steam Turbine ◽  
Gas Turbine ◽  
Power Output ◽  
Gas Turbines ◽  
Power Plants ◽  
Steam Injection ◽  
Combined Cycle ◽  
Producer Gas ◽  
Cycle Systems

Biomass can be converted to energy via direct combustion or thermo-chemical conversion to liquid or gas fuels. This study focuses on burning producer gases derived from gasifying biomass wastes to produce power. Since the producer gases are usually low calorific values (LCV), the power plants performance under various operating conditions has not yet been proven. In this study, system performance calculations are conducted for 5MWe power plants. The power plants considered include simple gas turbine systems, steam turbine systems, combined cycle systems, and steam injection gas turbine systems (STIG) using the producer gas with low calorific values at approximately 30% and 15% of the natural gas heating value (on a mass basis). The LCV fuels are shown to impose high back compressor pressure and produces increased power output due to increased fuel flow. Turbine nozzle throat area is adjusted to accommodate additional fuel flows to allow compressor operate within safety margin. The best performance occurs when the designed pressure ratio is maintained by widening nozzle openings, even though the TIT is reduced under this adjustment. Power augmentations under four different ambient conditions are calculated by employing gas turbine inlet fog cooling. Comparison between inlet fog cooling and steam injection using the same amount of water mass flow indicates that steam injection is less effective than inlet fog cooling in augmenting power output. Maximizing steam injection, at the expense of supplying the steam to the steam turbine, significantly reduces both the efficiency and the output power of the combined cycle. This study indicates that the performance of gas turbine and combined cycle systems fueled by the LCV fuels could be very different from the familiar behavior of natural gas fired systems. Care must be taken if on-shelf gas turbines are modified to burn LCV fuels.

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