Fog System Performance in Power Augmentation of Heavy Duty Power Generating Gas Turbines Model 7EA

2000 ◽  
Author(s):  
Steve Ingistov
Keyword(s):  
Gas Turbines ◽  
Cooling System ◽  
Axial Compressor ◽  
Ambient Air ◽  
Water Mist ◽  
Water Evaporation ◽  
Air Cooling ◽  
Evaporation Process ◽  
Ambient Conditions ◽  
Compression Process

Ambient air temperature plays significant role in performance of a Gas Turbine. Frequently Gas Turbines in electrical power generation are single rotor and are directly coupled to the Electrical Generators. These machines normally operate 8,000 hours per calendar year under the 100% load. The control of the combustion air flow is achieved by modulating compressor Inlet Guide Vanes (IGV). The single shaft axial compressor consumes as a rule of thumb more than 50% of turbine useful expansion work. Axial compressor is high-volume, moderate discharge pressure machine. Its power demand to discharge ambient air to the turbine combustion system is very dependent on ambient conditions such as pressure, temperature and relative humidity. The optimization of the axial compressor aerodynamic loading under various ambient conditions is therefore mandatory. During the hot and humid summer days, especially from the noon time to 6:00 PM, the demand for the power is at its maximum. This Paper describes selection, design and installation of the Inlet Air Cooling System. (IACS). The selected IACS is fine water mist, FOG. FOG System (FS) was selected because of its efficiency and because the clean water was available. FS incorporates Fog Generating Skid (FGS) and Fog Curtain (FC). FC is comprised of lateral lines with equally spaced. FOG Nozzles (FN). The FN is specially designed to generate individual “Fog Cones” that efficiently dissipate the water particles in the space. Fine water particles are atomized by incoming air in the Inlet Air (IA) duct. The homogenous mixture of FOG and IA is required to enhance the water mist particles evaporation process. In cases when the FS works in tandem with Evaporative Cooler (EC) most of the FOG particles are “injected” into the compressor suction. The injected FOG particles start to evaporate during the IA compression process. The water evaporation process simultaneously causes cooling of the IA being compressed. The result is reduced compression work and improved performance of GT.

Influence of Water Droplet Size and Temperature on Wet Compression

2007 ◽  
Author(s):  
M. Bianchi ◽  
F. Melino ◽  
A. Peretto ◽  
P. R. Spina ◽  
S. Ingistov
Keyword(s):  
Gas Turbine ◽  
Water Droplet ◽  
Droplet Diameter ◽  
Axial Compressor ◽  
Combined Cycle ◽  
Water Evaporation ◽  
Air Cooling ◽  
Compression Process ◽  
Two Phase ◽  
Wet Compression

In the last years, among all different gas turbine inlet air cooling techniques, an increasing attention to fogging approach is dedicated. The various fogging strategies seem to be a good solution to improve gas turbine or combined cycle produced power with low initial investment cost and less installation downtime. In particular, overspray fogging and interstage injection involve two-phase flow consideration and water evaporation during compression process (also known as wet compression). According to the Author’s knowledge, the field of wet compression is not completely studied and understood. In the present paper, all the principal aspects of wet compression and in particular the influence of injected water droplet diameter and surface temperature, and their effect on gas turbine performance and on the behavior of the axial compressor (change in axial compressor performance map due to the water injection, redistribution of stage load, etc.) are analyzed by using a calculation code, named IN.FO.G.T.E. (INterstage FOgging Gas Turbine Evaluation), developed and validated by the Authors.

scholarly journals Innovative Turbine Intake Air Cooling Systems and Their Rational Designing

Energies ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 6201
Author(s):  
Andrii Radchenko ◽  
Eugeniy Trushliakov ◽  
Krzysztof Kosowski ◽  
Dariusz Mikielewicz ◽  
Mykola Radchenko
Keyword(s):  
Gas Turbines ◽  
Maximum Rate ◽  
Cooling System ◽  
Ambient Air ◽  
Cooling Capacity ◽  
Climatic Conditions ◽  
Air Cooling ◽  
Thermal Loads ◽  
Cooling Systems ◽  
Air Cooling System

The efficiency of cooling ambient air at the inlet of gas turbines in temperate climatic conditions was analyzed and reserves for its enhancing through deep cooling were revealed. A method of logical analysis of the actual operation efficiency of turbine intake air cooling systems in real varying environment, supplemented by the simplest numerical simulation was used to synthesize new solutions. As a result, a novel trend in engine intake air cooling to 7 or 10 °C in temperate climatic conditions by two-stage cooling in chillers of combined type, providing an annual fuel saving of practically 50%, surpasses its value gained due to traditional air cooling to about 15 °C in absorption lithium-bromide chiller of a simple cycle, and is proposed. On analyzing the actual efficiency of turbine intake air cooling system, the current changes in thermal loads on the system in response to varying ambient air parameters were taken into account and annual fuel reduction was considered to be a primary criterion, as an example. The improved methodology of the engine intake air cooling system designing based on the annual effect due to cooling was developed. It involves determining the optimal value of cooling capacity, providing the minimum system sizes at maximum rate of annual effect increment, and its rational value, providing a close to maximum annual effect without system oversizing at the second maximum rate of annual effect increment within the range beyond the first maximum rate. The rational value of design cooling capacity provides practically the maximum annual fuel saving but with the sizes of cooling systems reduced by 15 to 20% due to the correspondingly reduced design cooling capacity of the systems as compared with their values defined by traditional designing focused to cover current peaked short-term thermal loads. The optimal value of cooling capacity providing the minimum sizes of cooling system is very reasonable for applying the energy saving technologies, for instance, based on the thermal storage with accumulating excessive (not consumed) cooling capacities at lowered current thermal loads to cover the peak loads. The application of developed methodology enables revealing the thermal potential for enhancing the efficiency of any combustion engine (gas turbines and engines, internal combustion engines, etc.).

Exceeding 2000 K at Turbine Inlet: Relative Cooling With Liquid for Gas Turbines — Integrated Systems

2003 ◽  
Author(s):  
Sandu Constantin ◽  
Dan Brasoveanu
Keyword(s):  
Gas Turbine ◽  
Relative Motion ◽  
Thermal Efficiency ◽  
Gas Turbines ◽  
State Of The Art ◽  
Cooling System ◽  
Ambient Air ◽  
Air Cooling ◽  
Cooling Systems ◽  
Turbine Inlet

Thermal efficiency of gas turbines is critically dependent on temperature of burnt gases at turbine inlet, the higher this temperature the higher the efficiency. Stochiometric combustion would provide maximum efficiency, but in the absence of an internal cooling system, turbine blades cannot tolerate gas temperatures exceeding 1300 K. This temperature yields a low thermal efficiency, about 15% below the level provide by stoicthiometric combustion. Conventional engines rely on air for blade and disk cooling and limit temperature at turbine inlet to about 1500 K. These engines gain about 3% compared to non-cooled designs. Gas turbines with state of the art air-cooling systems reach up to 1700–1750 K, boosting thermal efficiency by another 2–3%. These temperatures are near the limit allowed by air-cooling systems. Cooling systems with air are easier to design, but air has a low heat transfer capacity, and compressor air bleeding lowers the overall efficiency of engines (less air remains available for combustion). In addition, these systems waste most of the heat extracted from turbine for cooling. In principle, gas turbines could be cooled with liquid. Half a century ago, designers tried to place the pump for coolant recirculation on the engine stator. Liquid was allowed to boil inside the turbine. Seals for parts in relative motion cannot prevent loss of superheated vapors, therefore these experiments failed. To circumvent this problem, another design relied on thermal gradients to promote recirculation from blade tip to root. Liquid flow and cooling capacity were minute. Therefore it was assumed that liquid couldn’t be used for gas turbine cooling. This is an unwarranted assumption. The relative motion between engine stator and rotor provides abundant power for pumps placed on the rotor. The heat exchanger needed for cooling the liquid with ambient air could also be embedded in the rotor. In fact, the entire cooling system can be encapsulated within the rotor. In this manner, the sealing problem is circumvented. Compared to state of the art air-cooling methods, such a cooling system would increase thermal efficiency of any gas turbine by 6%–8%, because stoichimoetric fuel-air mixtures would be used (maybe even with hydrogen fuel). In addition, these systems would recuperate most of the heat extracted from turbine for cooling, are expected to be highly reliable and to increase specific power of gas turbines by 400% to 500%.

Applications of Gas Turbine Plants With Cooled Compressor Intake Air

2001 ◽  
Author(s):  
E. Kakaras ◽  
A. Doukelis ◽  
J. Scharfe
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Cooling System ◽  
Ambient Air ◽  
Climatic Conditions ◽  
Air Cooling ◽  
Iso Standard ◽  
Air Temperatures ◽  
Air Cooling System ◽  
Alternative Scenarios

The operation of gas turbines at ambient air temperatures higher than the ISO standard conditions (15°C) causes performance penalties both in the generated power and the efficiency of the engine. At high inlet-air temperatures, there can be a power loss of more than 20% combined with a significant increase in specific fuel consumption, compared to the ISO standard conditions. Thus, over a long period of time, gas turbines have a lower power output and efficiency than the equipment could actually perform. It is the purpose of this work to present the possibilities and advantages from the integration of an innovative air-cooling system for reducing the gas turbine intake-air temperature. The advantages of this system are demonstrated by examining alternative scenarios of usage, representative of different countries and different climatic conditions.

A Parametric Study of Interstage Injection on GE Frame 7EA Gas Turbine

2004 ◽  
Author(s):  
M. Bagnoli ◽  
M. Bianchi ◽  
F. Melino ◽  
A. Peretto ◽  
P. R. Spina ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Axial Compressor ◽  
Combined Cycle ◽  
Water Evaporation ◽  
Air Cooling ◽  
Phase Flow ◽  
Compression Process ◽  
Two Phase ◽  
Wet Compression ◽  
Flow Compression

In recent years, among various available inlet air cooling techniques for gas turbine power enhancement, high pressure fogging has seen an increasing attention mainly because of its comparatively low initial investment cost and less downtime for its installation. The various fogging strategies such as inlet evaporative, overspray (or wet compression) and interstage injection have been implemented in simple and combined cycle applications. Unlike wet compression, air at the compressor inlet is not fully saturated with the interstage injection. However, both wet compression and interstage injection involve multi-phase flow and water evaporation during the compression process. The phenomenon of two phase flow compression in axial compressor is not yet fully understood. This paper investigates effects of interstage injection on the performance of a GE Frame 7EA gas turbine using aero-thermodynamic modeling. In addition to estimating the overall gas turbine performance changes achievable with the interstage injection approach, the study presented here discusses impact of interstage injection on the stage-by-stage compressor performance characteristics of the selected gas turbine. The plausible reasons for the observed performance changes are discussed.

Upgrade of the Intake Air Cooling System for a Heavy-Duty Industrial Gas Turbine

2011 ◽  
Author(s):  
Steve Ingistov ◽  
Mustapha Chaker
Keyword(s):  
Gas Turbines ◽  
Cooling System ◽  
Air Cooling ◽  
Heavy Duty ◽  
Ambient Conditions ◽  
Fog Water ◽  
Media Type ◽  
Air Cooling System ◽  
Evaporative Cooling System ◽  
And Performance

This paper describes continued efforts, spanning over number of years at the Watson Cogeneration plant located in Carson California, to improve the intake air cooling system in enhancing power output and performance of the four existing heavy-duty GE 7EA gas turbines. In early 2010, a decision was made to remove the media-type evaporative cooling system from one of the GT units (Unit #4) and rely completely on the high pressure fogging system to cool the compressor inlet air for power augmentation. The reasons and the efforts made for modifying the intake air system are elaborated in this paper including discussion on the results obtained due to implemented changes. Steam turbine condensate at 49 °C is utilized as the fogging water in contrast to the commonly used demineralized water at the ambient conditions. A discussion on the implication of using high temperature fog water is included here.

Inlet Air Cooling Applied to Combined Cycle Power Plants: Influence of Site Climate and Thermal Storage Systems

2008 ◽  
Vol 130 (2) ◽  
Author(s):  
Nicola Palestra ◽  
Giovanna Barigozzi ◽  
Antonio Perdichizzi
Keyword(s):  
Power Output ◽  
Parametric Analysis ◽  
Power Plants ◽  
Cooling System ◽  
Thermal Storage ◽  
Combined Cycle ◽  
Operating Conditions ◽  
Air Cooling ◽  
Ambient Conditions ◽  
Cooling Systems

The paper presents the results of an investigation on inlet air cooling systems based on cool thermal storage, applied to combined cycle power plants. Such systems provide a significant increase of electric energy production in the peak hours; the charge of the cool thermal storage is performed instead during the night time. The inlet air cooling system also allows the plant to reduce power output dependence on ambient conditions. A 127MW combined cycle power plant operating in the Italian scenario is the object of this investigation. Two different technologies for cool thermal storage have been considered: ice harvester and stratified chilled water. To evaluate the performance of the combined cycle under different operating conditions, inlet cooling systems have been simulated with an in-house developed computational code. An economical analysis has been then performed. Different plant location sites have been considered, with the purpose to weigh up the influence of climatic conditions. Finally, a parametric analysis has been carried out in order to investigate how a variation of the thermal storage size affects the combined cycle performances and the investment profitability. It was found that both cool thermal storage technologies considered perform similarly in terms of gross extra production of energy. Despite this, the ice harvester shows higher parasitic load due to chillers consumptions. Warmer climates of the plant site resulted in a greater increase in the amount of operational hours than power output augmentation; investment profitability is different as well. Results of parametric analysis showed how important the size of inlet cooling storage may be for economical results.

Relative Cooling With Liquid for Gas Turbines: Part I — A Solution for Exceeding 2000 K at Turbine Inlet

2001 ◽  
Author(s):  
Sandu Constantin ◽  
Dan Brasoveanu
Keyword(s):  
Thermal Efficiency ◽  
Gas Turbines ◽  
Cooling System ◽  
Turbine Blades ◽  
Air Cooling ◽  
Liquid Cooling ◽  
Cooling Systems ◽  
Turbine Inlet ◽  
Cooling Methods ◽  
Current Operating

Abstract The thermal efficiency of gas turbines is critically dependent on the temperature of burnt gases at turbine inlet, the higher this temperature the higher the efficiency. Stochiometric combustion would provide maximum efficiency, but in the absence of an internal cooling system, turbine blades cannot tolerate gas temperatures that exceed 1300 K. Therefore, for this temperature, the thermal efficiency of turbine engine is 40% less than theoretical maximum. Conventional air-cooling techniques of turbine blades allow inlet temperatures of about 1500 K on current operating engines yielding thermal efficiency gains of about 6%. New designs, that incorporate advanced air-cooling methods allows inlet temperatures of 1750–1800 K, with a thermal efficiency gain of about 6% relative to current operating engines. This temperature is near the limit allowed by air-cooling systems. Turbine blades can be cooled with air taken from the compressor or with liquid. Cooling systems with air are easier to design but have a relatively low heat transfer capacity and reduce the efficiency of the engine. Some cooling systems with liquid rely on thermal gradients to promote re-circulation from the tip to the root of turbine blades. In this case, the flow and cooling of liquid are restricted. For best results, cooling systems with liquid should use a pump to re-circulate the coolant. In the past, designers tried to place this pump on the engine stator and therefore were unable to avoid high coolant losses because it is impossible to reliably seal the stator-rotor interface. Therefore it was assumed that cooling systems with liquid could not incorporate pumps. This is an unwarranted assumption as shown studying the system in a moving frame of reference that is linked to the rotor. Here is the crucial fact overlooked by previous designers. The relative motion of engine stator with respect to the rotor is sufficient to motivate a cooling pump. Both the pump and heat exchange system that is required to provide rapid cooling of liquid with cold ambient air, could be located within the rotor. Therefore, the entire cooling system can be encapsulated within the rotor and the sealing problem is circumvented. Compared to recent designs that use advanced air-cooling methods, such a liquid cooling system would increase the thermal efficiency by 8%–11% because the temperatures at turbine inlet can reach stoichiometric levels and most of the heat extracted from turbine during cooling is recuperated. The appreciated high reliability of the system will permit a large applicability in aerospace propulsion.

Recognising the Viability of Cooling Gas Turbine Inlet Air in Colder Regions by Using Low Pressure Fogging Techniques

2002 ◽  
Author(s):  
John Confurius
Keyword(s):  
Ambient Temperature ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Cooling System ◽  
Low Pressure ◽  
Air Cooling ◽  
Turbine Inlet ◽  
The World

The profits that can be gained by use of inlet air cooling on gas turbines has been recognised for quite some time now and the systems installed throughout the world have shown the users in the gas turbine field that cooling indeed can be used to boost power at times when the ambient temperature reaches or exceeds the ISO rating temperature of the gas turbine. Drawback however being that the initial investment asked of the gas turbine user is rather large thus only justifying a cooling system in regions where the outdoor temperatures exceed the ISO rating time and again due to the climate in that region. Lately gas turbine users in colder climates have become interested in power augmentation during their short summer, however there is no justification for an investment like necessary when installing one of the presently available systems on the market. As the question reached us from more and more of our clients it stimulated us to go out and search for a low-investment solution to this problem. This resulted in the world’s first low pressure gas turbine inlet cooling system.

scholarly journals Gas turbine unite inlet air cooling by using an excessive refrigeration capacity of absorption-ejector chiller in booster air cooler

2018 ◽  
Vol 70 ◽  
pp. 03012 ◽  
Author(s):  
Roman Radchenko ◽  
Andrii Radchenko ◽  
Serhiy Serbin ◽  
Serhiy Kantor ◽  
Bohdan Portnoi
Keyword(s):  
Gas Turbine ◽  
Cooling System ◽  
Ambient Air ◽  
Cooling Capacity ◽  
Climatic Conditions ◽  
Air Cooling ◽  
Two Stage ◽  
Air Cooler ◽  
Refrigeration Capacity ◽  
Heat Loads

Two-stage Gas turbine unite (GTU) inlet air cooling by absorption lithium-bromide chiller (ACh) to the temperature 15 °C and by refrigerant ejector chiller (ECh) to 10 °C through utilizing the turbine exhaust gas heat for changeable ambient air temperatures and corresponding heat loads on the air coolers for the south Ukraine climatic conditions is analysed. An excessive refrigeration capacity of combined absorption-ejector chiller (AECh) exceeding the current heat loads and generated at decreased heat loads on the air coolers at the inlet of GTU can be used for covering increased heat loads to reduce the refrigeration capacity of AECh. The GTU inlet air cooling system with an ambient air precooling booster stage and a base two-stage cooling air to the temperature 10 °C by AECh is proposed. The AECh excessive cooling capacity generated during decreased heat loads on the GTU inlet air coolers is conserved in the thermal accumulator and used for GTU inlet air precooling in a booster stage of air cooler during increased heat loads. There is AECh cooling capacity reduction by 50% due to the use of a booster stage for precooling GTU inlet ambient air at the expense of an excessive cooling capacity accumulated in the thermal storage.

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