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.%.

Influence of Steam Injection on Thermal Efficiency and Operating Temperature of GE-F5 Gas Turbines Applying VODOLEY System

2005 ◽  
Author(s):  
Mohsen Ghazikhani ◽  
Nima Manshoori ◽  
Davood Tafazoli
Keyword(s):  
Power Plant ◽  
Ambient Temperature ◽  
Gas Turbine ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Thermal Efficiency ◽  
Gas Turbines ◽  
Steam Injection ◽  
Gas Turbine Cycle

An industrial gas turbine has the characteristic that turbine output decreases on hot summer days when electricity demand peaks. For GE-F5 gas turbines of Mashad Power Plant when ambient temperature increases 1° C, compressor outlet temperature increases 1.13° C and turbine exhaust temperature increases 2.5° C. Also air mass flow rate decreases about 0.6 kg/sec when ambient temperature increases 1° C, so it is revealed that variations are more due to decreasing in the efficiency of compressor and less due to reduction in mass flow rate of air as ambient temperature increases in constant power output. The cycle efficiency of these GE-F5 gas turbines reduces 3 percent with increasing 50° C of ambient temperature, also the fuel consumption increases as ambient temperature increases for constant turbine work. These are also because of reducing in the compressor efficiency in high temperature ambient. Steam injection in gas turbines is a way to prevent a loss in performance of gas turbines caused by high ambient temperature and has been used for many years. VODOLEY system is a steam injection system, which is known as a self-sufficient one in steam production. The amount of water vapor in combustion products will become regenerated in a contact condenser and after passing through a heat recovery boiler is injected in the transition piece after combustion chamber. In this paper the influence of steam injection in Mashad Power Plant GE-F5 gas turbine parameters, applying VODOLEY system, is being observed. Results show that in this turbine, the turbine inlet temperature (T3) decreases in a range of 5 percent to 11 percent depending on ambient temperature, so the operating parameters in a gas turbine cycle equipped with VODOLEY system in 40° C of ambient temperature is the same as simple gas turbine cycle in 10° C of ambient temperature. Results show that the thermal efficiency increases up to 10 percent, but Back-Work ratio increases in a range of 15 percent to 30 percent. Also results show that although VODOLEY system has water treatment cost but by using this system the running cost will reduce up to 27 percent.

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.

scholarly journals Impact of Cooling with Thermal Barrier Coatings on Flow Passage in a Gas Turbine

Energies ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 85
Author(s):  
Yuanzhe Zhang ◽  
Pei Liu ◽  
Zheng Li
Keyword(s):  
Gas Turbine ◽  
Thermal Barrier Coatings ◽  
Thermal Efficiency ◽  
Gas Turbines ◽  
Thermal Barrier ◽  
Power Sources ◽  
Barrier Coatings ◽  
Flow Passage ◽  
Blade Cooling ◽  
The Impact

Inlet temperature is vital to the thermal efficiency of gas turbines, which is becoming increasingly important in the context of structural changes in power supplies with more intermittent renewable power sources. Blade cooling is a key method for gas turbines to maintain high inlet temperatures whilst also meeting material temperature limits. However, the implementation of blade cooling within a gas turbine—for instance, thermal barrier coatings (TBCs)—might also change its heat transfer characteristics and lead to challenges in calculating its internal temperature and thermal efficiency. Existing studies have mainly focused on the materials and mechanisms of TBCs and the impact of TBCs on turbine blades. However, these analyses are insufficient for measuring the overall impact of TBCs on turbines. In this study, the impact of TBC thickness on the performance of gas turbines is analyzed. An improved mathematical model for turbine flow passage is proposed, considering the impact of cooling with TBCs. This model has the function of analyzing the impact of TBCs on turbine geometry. By changing the TBCs’ thickness from 0.0005 m to 0.0013 m, its effects on turbine flow passage are quantitatively analyzed using the proposed model. The variation rules of the cooling air ratio, turbine inlet mass flow rate, and turbine flow passage structure within the range of 0.0005 m to 0.0013 m of TBC thicknesses are given.

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.

Analysis of Operational Effects on Cooled H-Class Gas Turbines

2019 ◽  
Author(s):  
Selcuk Can Uysal ◽  
James B. Black
Keyword(s):  
Gas Turbine ◽  
Turbine Blade ◽  
Power Output ◽  
Thermal Efficiency ◽  
Gas Turbines ◽  
Cooling System ◽  
Engine Performance ◽  
Heat Rate ◽  
Operating Conditions ◽  
Performance Parameters

Abstract During the operation of an industrial gas turbine, the engine deviates from its new condition performance because of several effects including dirt build-up, compressor fouling, material erosion, oxidation, corrosion, turbine blade burning or warping, thermal barrier coating (TBC) degradation, and turbine blade cooling channel clogging. Once these problems cause a significant impact on engine performance, maintenance actions are taken by the operators to restore the engine to new performance levels. It is important to quantify the impacts of these operational effects on the key engine performance parameters such as power output, heat rate and thermal efficiency for industrial gas turbines during the design phase. This information can be used to determine an engine maintenance schedule, which is directly related to maintenance costs during the anticipated operational time. A cooled gas turbine performance analysis model is used in this study to determine the impacts of the TBC degradation and compressor fouling on the engine performance by using three different H-Class gas turbine scenarios. The analytical tool that is used in this analysis is the Cooled Gas Turbine Model (CGTM) that was previously developed in MATLAB Simulink®. The CGTM evaluates the engine performance using operating conditions, polytropic efficiencies, material properties and cooling system information. To investigate the negative impacts on engine performance due to structural changes in TBC material, compressor fouling, and their combined effect, CGTM is used in this study for three different H-Class engine scenarios that have various compressor pressure ratios, turbine inlet temperatures, and power and thermal efficiency outputs; each determined to represent different classes of recent H-Class gas turbines. Experimental data on the changes in TBC performance are used as an input to the CGTM as a change in the TBC Biot number to observe the impacts on engine performance. The effect of compressor fouling is studied by changing the compressor discharge pressures and polytropic compressor efficiencies within the expected reduction ranges. The individual and combined effects of compressor fouling and TBC degradation are presented for the shaft power output, thermal efficiency and heat rate performance parameters. Possible improvements for the designers to reduce these impacts, and comparison of the reductions in engine performance parameters of the studied H-Class engine scenarios are also provided.

Power Enhancement of Gas Turbine Plant by Intake Air Fog Cooling

2015 ◽  
Vol 3 (1) ◽  
Author(s):  
J. P. Yadav ◽  
Bharat Raj Singh ◽  
Onkar Singh
Keyword(s):  
Gas Turbine ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Power Output ◽  
Gas Turbines ◽  
Ambient Air ◽  
Summer Season ◽  
Ambient Conditions ◽  
Power Enhancement

Although gas turbines are known as constant volume machines, but its performance considerably depends upon the ambient air temperature and mass flow rate. During summer season the density of the air decreases which affects the mass flow rate and ultimately the power output of a gas turbine is reduced. In order to overcome this situation several techniques are already in the practice and one of the most effective and economical is adopting the inlet fog cooling, and this technique basically enhances the power output of the machine. The cooling of ambient air by fog cooling up to wet bulb temperature increases the mass flow rate on account of increase in air density, as a result it ultimately increases the power output of a gas turbine. Fogging is applied with consideration of relative humidity of ambient air not only during summer season but also during dry days of summer season in order to increase the power output of gas turbine. This paper describes the effect on percentage enhancement of power out adopting various fuel options with low and high humidity ambient conditions. The result indicates the potential increase in the power output up to 14%. It is also observed that the total cost of power production increases due to increase in fuel consumption on account of enhanced power output. Thus the best suitable selling cost of power should be selected to compensate the increased investment on fuel cost.

scholarly journals Fog and Overspray Cooling for Gas Turbine Systems With Low Calorific Value Fuels

2006 ◽  
Author(s):  
Jobaidur Rahman Khan ◽  
Ting Wang
Keyword(s):  
Gas Turbine ◽  
Output Power ◽  
Power Output ◽  
Thermal Efficiency ◽  
Gas Turbines ◽  
Alternative Fuels ◽  
Calorific Value ◽  
Ambient Conditions ◽  
Turbine Inlet ◽  
Compressor Power

During the summer, power output and the efficiency of gas turbines deteriorate significantly. Gas turbine inlet air fog cooling is considered a simple and cost-effective method to increase power output as well as, sometimes, thermal efficiency. During fog cooling, water is atomized to micro-scaled droplets and introduced into the inlet airflow. In addition to cooling the inlet air, overspray can further enhance output power by intercooling the compressor. With continued increase of volatility of natural gas prices and concerns regarding national energy security, alternative fuels such as low calorific value (LCV) synthetic gases (syngas) derived from gasification of coal, petroleum coke, or biomass are considered as important common fuels in the future. The effect of fogging/overspray on LCV fuel fired gas turbine systems is not clear. This paper specifically investigates this issue by developing a wet compression thermodynamic model that considers additional water and LCV fuel mass flows, non-stoichiometric combustion, and the auxiliary fuel compressor power. An in-house computational program, FogGT, has been developed to study the theoretical gas turbine performance by fixing the pressure ratio and turbine inlet temperature (TIT) assuming the gas turbine has been designed or modified to take in the additional mass flow rates from overspray and LCV fuels. Two LCV fuels of approximately 8% and 15% of the NG heating values, are considered respectively. Parametric studies have been performed to consider different ambient conditions and various overspray ratios with fuels of different low heating values. The results show, when LCV fuels are burned, the fuel compressor consumes about 10–18% of the turbine output power in comparison with 2% when NG is burned. LCV fueled GT is about 10–16% less efficient than NG fueled GT and produces 10–24% of net output power even though LCV fuels significantly increase fuel compressor power. When LCV fuels are burned, saturated fogging can achieve a net output power increases approximately 1–2%, while 2% overspray can achieve 20% net output enhancement. As the ambient temperature or relative humidity increases, the net output power decreases. Fog/overspray could either slightly increase or decrease the thermal efficiency depending on the ambient conditions.

Water Injection Evaporation in Frame 7EA Gas Turbine Wrapper

2017 ◽  
Author(s):  
Michele Bianchi ◽  
Andrea De Pascale ◽  
Francesco Melino ◽  
Antonio Peretto ◽  
Sasha Savic
Keyword(s):  
Gas Turbine ◽  
Droplet Size ◽  
Liquid Water ◽  
Gas Turbines ◽  
Water Injection ◽  
Steam Injection ◽  
Operating Conditions ◽  
Nox Abatement ◽  
The Impact ◽  
Calculation Code

A Southern California cogeneration plant is comprised of four GE-made Frame No 7, Model EA, heavy duty gas turbines driving Electrical Generators. Turbine exhaust gases are routed into the heat recovery steam generators (HRSG) of the split level. The HRSG are furnished with supplemental firing in order to boost the production of the steam. The produced NOX abatement is realized by the continuous steam injection and selective catalyst reduction (SCR). In order to reduce the steam consumption for NOX abatement, water injection in combustion chamber can be taken into account. Unfortunately, available gas turbine combustor cannot be used to inject water directly into the liner (and thus maximize the impact of water injection compared to steam injection); for this reason, an alternative solution was investigated which consists on water injection into the combustor wrapper. By doing this, effects on NOX abatement are similar to those of steam injection for power augmentation, namely only about 30% of water injected this way will actually quench the NOX, the rest flowing through the dilution holes. To ensure no impact of water injection on the combustor hardware’s integrity, any liquid droplets injected into the wrapper shall evaporate prior to reaching the liner. In order to estimate the behavior of liquid water droplets injected into the wrapper, a calculation code was developed by University of Bologna. This calculation code is able to estimate the evaporation rate of a spray of liquid water by calculating the droplets diameter reduction, the air temperature drop, etc. as function of boundary conditions. More in details, the aim of this study is to estimate the maximum droplet sizes to ensure the full evaporation of the water and to eliminate negative effects on the combustor life. In order to achieve this goal, a parametric study has been developed, changing the droplet size to calculate the time needed for full evaporation and compare this with the time of droplet travel from the injection point to the first dilution holes of the combustor liner. More in details, it was calculated, under various gas turbine operating conditions, what would be the maximal droplet size needed to evaporate within the available residence time into the wrapper.

scholarly journals Design of Gas Turbine Exhaust Heat Recovery Boiler Systems

1984 ◽  
Author(s):  
V. L. Eriksen ◽  
J. M. Froemming ◽  
M. R. Carroll
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Heat Recovery ◽  
Performance Criteria ◽  
Exhaust Heat ◽  
Recovery Boilers ◽  
Gas Turbine Exhaust ◽  
The Impact ◽  
Exhaust Heat Recovery ◽  
Turbine Exhaust

Heat recovery boilers utilizing the exhaust from gas turbines continue to be viable as industrial cogeneration systems. This paper outlines the types of heat recovery boilers available for use with gas turbines (1–100 MW). It discusses the design and performance criteria for both unfired and supplementary fired gas turbine exhaust heat recovery boilers of single and multiple pressure levels. Equations to assist in energy balances are included along with design features of heat recovery system components. The economic incentive to achieve the maximum practical heat recovery versus the impact on boiler design and capital cost are examined and discussed. It is intended that the information presented in this paper will be of use to individuals who are not intimately familiar with gas turbine heat recovery systems so that they can better specify and evaluate potential systems.

Thermal-Economic Evaluation of Evaporative Inlet Cooling Methods for Ray Gas Turbine Power Plant

2004 ◽  
Author(s):  
Sepehr Sanaye ◽  
Abbasali Farhad ◽  
Mohsen Ebrahimi
Keyword(s):  
Economic Evaluation ◽  
Power Plant ◽  
Gas Turbine ◽  
Power Output ◽  
Thermal Efficiency ◽  
Gas Turbines ◽  
Evaporative Cooling ◽  
Ambient Conditions ◽  
Operational Conditions ◽  
Cooling Methods

The ambient conditions (temperature, pressure and humidity) affect the gas turbine power output and thermal efficiency [1–8]. Increasing one Celsius degree of ambient temperature decreases the power output for about 0.5 to 0.9 percent and the thermal efficiency for about 0.25 percent. Evaporating cooling is efficient and cost effective method for gas turbine inlet cooling to improve the power output and efficiency, specially in hot and dry regions. A systematic thermo-economic evaluation of the three evaporative inlet cooling methods applied to existing 25 MW Fiat gas turbine in Ray power plant, is presented in this paper. The three inlet cooling methods considered are: evaporative inlet fogging, media type evaporative cooling and inlet cooling through air washer. The investment and maintenance costs, the income from increasing the power output, the costs of increasing fuel consumption, and power loss due to pressure drops, were estimated and the payback periods for the mentioned evaporative inlet cooling methods were obtained and compared. The suitable evaporative cooling method for various operational conditions is proposed for 25 MW Fiat gas turbines.

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