On Thermodynamics of Gas-Turbine Cycles: Part 3—Thermodynamic Potential and Limitations of Cooled Reheat-Gas-Turbine Combined Cycles

1986 ◽  
Vol 108 (1) ◽  
pp. 160-168 ◽  
Author(s):  
M. A. El-Masri
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Closed Loop ◽  
Elevated Temperatures ◽  
Pressure Ratio ◽  
Air Cooling ◽  
Full Potential ◽  
Evaporative Water ◽  
Combined Cycles ◽  
Cooling Technology

Reheat gas turbines have fundamental thermodynamic advantages in combined cycles. However, a larger proportion of the turbine expansion path is exposed to elevated temperatures, leading to increased cooling losses. Identifying cooling technologies which minimize those losses is crucial to realizing the full potential of reheat cycles. The strong role played by cooling losses in reheat cycles necessitates their inclusion in cycle optimization. To this end, the models for the thermodynamics of combined cycles and cooled turbines presented in Parts 1 and 2 of this paper have been extended where needed and applied to the analysis of a wide variety of cycles. The cooling methods considered range from established air-cooling technology to methods under current research and development such as air-transpiration, open-loop, and closed-loop water cooling. Two schemes thought worthy of longer-term consideration are also assessed. These are two-phase transpiration cooling and the regenerative thermosyphon. A variety of configurations are examined, ranging from Brayton-cycles to one or two-turbine reheats, with or without compressor intercooling. Both surface intercoolers and evaporative water-spray types are considered. The most attractive cycle configurations as well as the optimum pressure ratio and peak temperature are found to vary significantly with types of cooling technology. Based upon the results of the model, it appears that internal closed-loop liquid cooling offers the greatest potential for midterm development. Hybrid systems with internally liquid-cooled nozzles and traditional air-cooled rotors seem most attractive for the near term. These could be further improved by using steam rather than air for cooling the rotor.

Comparative Investigation of Advanced Combined Cycles

2006 ◽  
Author(s):  
Hiwa Khaledi ◽  
Kazem Sarabchi
Keyword(s):  
Gas Turbine ◽  
Heat Recovery ◽  
Air Cooling ◽  
Actual Behavior ◽  
Exhaust Temperature ◽  
Blade Cooling ◽  
Large Influence ◽  
Combined Cycles ◽  
Cooling Technology ◽  
Turbine Exhaust

Combined cycles, at present, have a prominent role in the power generation and advanced combined cycles efficiencies have now reached to 60 percent. Examination of thermodynamic behavior of these cycles is still carried out to determine optimum configuration and optimum design conditions for any cycle arrangement. Actually the performance parameters of these cycles are under the influence of various parameters and therefore the recognition of the optimum conditions is quiet complicated. In this research an extensive thermodynamic model was developed for analyzing major parameters variations on gas turbine performance and different configurations of advanced steam cycles: dual and triple pressure cycles with and without reheating in steam turbine sections. In this model it is attempted to consider all factors that affect on actual behavior of these cycles such as blade cooling (air cooling) in gas turbine and different formulations for Heat Recovery Steam Generator (HRSG) performance calculation. Results show good agreement with manufactures data. In the case of gas turbine cycle, location of coolant extraction has large influence on cycle performance. For extraction from compressor end, improving blade cooling technology is suitable than increasing TIT. For mid stage extraction, improving blade cooling technology and TIT has similar effects on efficiency, while power is more sensitive to TIT. Coolant air precooling has large positive effect in high TIT and medium blade cooling technology, but always it increases power. Turbine exhaust temperature has large influence on optimum layout and configuration of HRSG, while for low exhaust temperatures increasing number of pressure levels increase power and heat recovery greatly, for high exhaust temperatures this leads lower enhancement in power and recovery. Second law efficiency of HRSG is proportional to power production in steam cycle. It decreases with increasing gas turbine exhaust temperature.

A Thermodynamic Analysis of Different Options to Break 60% Electric Efficiency in Combined Cycle Power Plants

2004 ◽  
Vol 126 (4) ◽  
pp. 770-785 ◽  
Author(s):  
Paolo Chiesa ◽  
Ennio Macchi
Keyword(s):  
Gas Turbine ◽  
Thermodynamic Analysis ◽  
Gas Turbines ◽  
Power Plants ◽  
Closed Loop ◽  
Open Loop ◽  
Combined Cycle ◽  
Rotor Blades ◽  
Air Cooling ◽  
Large Size

All major manufacturers of large size gas turbines are developing new techniques aimed at achieving net electric efficiency higher than 60% in combined cycle applications. An essential factor for this goal is the effective cooling of the hottest rows of the gas turbine. The present work investigates three different approaches to this problem: (i) the most conventional open-loop air cooling; (ii) the closed-loop steam cooling for vanes and rotor blades; (iii) the use of two independent closed-loop circuits: steam for stator vanes and air for rotor blades. Reference is made uniquely to large size, single shaft units and performance is estimated through an updated release of the thermodynamic code GS, developed at the Energy Department of Politecnico di Milano. A detailed presentation of the calculation method is given in the paper. Although many aspects (such as reliability, capital cost, environmental issues) which can affect gas turbine design were neglected, thermodynamic analysis showed that efficiency higher than 61% can be achieved in the frame of current, available technology.

Application of “H Gas Turbine” Design Technology to Increase Thermal Efficiency and Output Capability of the Mitsubishi M701G2 Gas Turbine

2005 ◽  
Vol 127 (2) ◽  
pp. 369-374 ◽  
Author(s):  
Y. Fukuizumi ◽  
J. Masada ◽  
V. Kallianpur ◽  
Y. Iwasaki
Keyword(s):  
Gas Turbine ◽  
Thermal Efficiency ◽  
Gas Turbines ◽  
Pressure Ratio ◽  
Turbine Blades ◽  
Combined Cycle ◽  
Load Test ◽  
Air Cooling ◽  
Load Testing ◽  
Design Development

Mitsubishi completed design development and verification load testing of a steam-cooled M501H gas turbine at a combined cycle power plant at Takasago, Japan in 2001. Several advanced technologies were specifically developed in addition to the steam-cooled components consisting of the combustor, turbine blades, vanes, and the rotor. Some of the other key technologies consisted of an advanced compressor with a pressure ratio of 25:1, active clearance control, and advanced seal technology. Prior to the M501H, Mitsubishi introduced cooling-steam in “G series” gas turbines in 1997 to cool combustor liners. Recently, some of the advanced design technologies from the M501H gas turbine were applied to the G series gas turbine resulting in significant improvement in output and thermal efficiency. A noteworthy aspect of the technology transfer is that the upgraded G series M701G2 gas turbine has an almost equivalent output and thermal efficiency as H class gas turbines while continuing to rely on conventional air cooling of turbine blades and vanes, and time-proven materials from industrial gas turbine experience. In this paper we describe the key design features of the M701G2 gas turbine that make this possible such as the advanced 21:1 compressor with 14 stages, an advanced premix DLN combustor, etc., as well as shop load test results that were completed in 2002 at Mitsubishi’s in-house facility.

Development of the Transpiration Air-Cooled Turbine for High-Temperature Dirty Gas Streams

1983 ◽  
Vol 105 (4) ◽  
pp. 821-825 ◽  
Author(s):  
J. Wolf ◽  
S. Moskowitz
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Power Plants ◽  
Pressure Ratio ◽  
Combined Cycle ◽  
Specific Power ◽  
Skin Permeability ◽  
Air Cooling ◽  
Initial Exposure ◽  
Flow Capacity

Studies of combined cycle electic power plants have shown that increasing the firing temperature and pressure ratio of the gas turbine can substantially improve the specific power output of the gas turbine as well as the combined cycle plant efficiency. Clearly this is a direction in which we can proceed to conserve the world’s dwindling petroleum fuel supplies. Furthermore, tomorrow’s gas turbines must do more than operate at higher temperature; they will likely face an aggressive hot gas stream created by the combustion of heavier oils or coal-derived liquid or gaseous fuels. Extensive tests have been performed on two rotating turbine rigs, each with a transpiration air cooled turbine operating in the 2600 to 3000°F (1427 to 1649°C) temperature range at increasing levels of gas stream particulates and alkali metal salts to simulate operation on coal-derived fuel. Transpiration air cooling was shown to be effective in maintaining acceptable metal temperatures, and there was no evidence of corrosion, erosion, or deposition. The rate of transpiration skin cooling flow capacity exhibited a minor loss in the initial exposure to the particulate laden gas stream of less than 100 hours, but the flow reduction was commensurate with that produced by normal oxidation of the skin material at the operating temperatures of 1350°F (732°C). The data on skin permeability loss from both cascade and engine tests compared favorably with laboratory furnace oxidation skin specimens. To date, over 10,000 hr of furnace exposure has been conducted. Extrapolation of the data to 50,000 hr indicates the flow capacity loss would produce an acceptable 50°F (10°C) increase in skin operating temperature.

scholarly journals Energy and Exergy Analysis of Coupled Cycles Utilizing New Generation Gas Turbines

2020 ◽  
Author(s):  
Chang Cho
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Closed Loop ◽  
Exergy Analysis ◽  
Cooling Process ◽  
Energy And Exergy ◽  
Energy And Exergy Analysis ◽  
Combined Cycles ◽  
New Generation

The potential execution of optimized gas-steam combined cycles built around the latest generation gas turbine motors is analyzed, by implies of energy/exergy equalizations. The options here considered are the warm gas turbine and the H-series with closed-loop steam edge cooling.Recreations of execution were run employing a well-tested Modular Code created at the Office of Vitality Designing of Florence and subsequently improved to incorporate the calculation of exergy pulverization of all sorts (warm transfer, friction, blending, and chemical irreversibilities). The edge cooling process is analyzed in detail because it is recognized to be of capital significance for execution optimization. The distributions of the relative exergy devastation for the two solutions both competent of achieving energy/exergy efficiencies within the extend of 60 percent are compared and the potential for advancement is examined<br>

scholarly journals Gas Turbine Uprating Programme Development and Testing of the GT11NM

1998 ◽  
Author(s):  
Christoph Schneider ◽  
Vladimir Navrotsky ◽  
Prith Harasgama
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Power Plants ◽  
Development Program ◽  
Combined Cycle ◽  
Economic Life ◽  
Air Cooling ◽  
Performance Improvements ◽  
Cooling Technology ◽  
Improved Performance

ABB has approximately 200 GT11N and GT11D type gas turbines currently operating in simple cycle and combined cycle power plants. Most of these machines are fairly mature with many approaching the end of their economic life. In order that the power producer may continue to operate a fleet with improved performance, Advanced Air Cooling Technology and Advanced Turbine Aerodynamics have been utilized to uprate these engines with the implementation of a completely new turbine module. The objective of the uprating program was to implement the advanced aero/cooling technology into a complete new turbine module with: • Improved power output for the gas turbine • Increase the GT cycle efficiency • Maintain or improve the gas turbine RAM (Reliability, Availability & Maintainability) • Reduce the Cost of Electricity • Maintain or reduce the emissions of the gas turbine The GT11NM gas turbine has been developed based on the GT11N which has been in operation since 1987 and Midland Cogeneration Venture (MCV-Midland, Michigan) was chosen to demonstrate the uprated GT11NM. The upate/retrofit of the GT11N engine was conducted in May/June 1997 and the resulting gas turbine - GT11NM has met and exceeded the performance goals set at the onset of the development program. The next sections detail the main changes to the turbine and the resulting performance improvements as established with the demonstration at Midland, Michigan.

A Thermodynamic Analysis of Different Options to Break 60% Electric Efficiency in Combined Cycle Power Plants

2002 ◽  
Author(s):  
Paolo Chiesa ◽  
Ennio Macchi
Keyword(s):  
Gas Turbine ◽  
Thermodynamic Analysis ◽  
Gas Turbines ◽  
Power Plants ◽  
Closed Loop ◽  
Open Loop ◽  
Combined Cycle ◽  
Rotor Blades ◽  
Air Cooling ◽  
Large Size

All major manufacturers of large size gas turbines are developing new techniques aimed at achieving net electric efficiency higher than 60% in combined cycle applications. An essential factor for this goal is the effective cooling of the hottest rows of the gas turbine. The present work investigates three different approaches to this problem: (i) the most conventional open-loop air cooling; (ii) the closed-loop steam cooling for vanes and rotor blades; (iii) the use of two independent closed-loop circuits: steam for stator vanes and air for rotor blades. Reference is made uniquely to large size, single shaft units and performance is estimated through an updated release of the thermodynamic code GS, developed at the Energy Dept. of Politecnico di Milano. A detailed presentation of the calculation method is given in the paper. Although many aspects (such as reliability, capital cost, environmental issues) which can affect gas turbine design were neglected, thermodynamic analysis showed that efficiency higher than 61% can be achieved in the frame of current, available technology.

scholarly journals Energy and Exergy Analysis of Coupled Cycles Utilizing New Generation Gas Turbines

2020 ◽  
Author(s):  
Chang Cho
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Closed Loop ◽  
Exergy Analysis ◽  
Cooling Process ◽  
Energy And Exergy ◽  
Energy And Exergy Analysis ◽  
Combined Cycles ◽  
New Generation

The potential execution of optimized gas-steam combined cycles built around the latest generation gas turbine motors is analyzed, by implies of energy/exergy equalizations. The options here considered are the warm gas turbine and the H-series with closed-loop steam edge cooling.Recreations of execution were run employing a well-tested Modular Code created at the Office of Vitality Designing of Florence and subsequently improved to incorporate the calculation of exergy pulverization of all sorts (warm transfer, friction, blending, and chemical irreversibilities). The edge cooling process is analyzed in detail because it is recognized to be of capital significance for execution optimization. The distributions of the relative exergy devastation for the two solutions both competent of achieving energy/exergy efficiencies within the extend of 60 percent are compared and the potential for advancement is examined<br>

Performance of Integrated Combined and Cogeneration Cycles Using Latest Gas Turbines

2004 ◽  
Author(s):  
Sanjay ◽  
Onkar Singh ◽  
B. N. Prasad
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Pressure Ratio ◽  
Utilization Efficiency ◽  
Inlet Temperature ◽  
Air Cooling ◽  
Specific Work ◽  
Fuel Utilization ◽  
Compressor Pressure Ratio ◽  
Cogeneration Cycle

The paper deals with the thermodynamic performance of combined and cogeneration cycles using the state of the art gas turbines. A configuration has been conceptualized using the latest gas turbine MS9001H that uses steam to cool the hot gas path components. In order to study the effect of cooling means, the same gas turbine is subjected to transpiration air cooling. Using the above mentioned conceptualized topping cycle, the bottoming cycle selected consists of a two-pressure reheat heat recovery steam generator (HRSG) with reheat having two options. First option is the integrated system (IS), which is a combined/cogeneration cycle, and the other is called the normal cogeneration cycle (NC). Both of these cycles are subjected to steam and transpiration air-cooling. The cycle performance is predicted based on parameteric study which has been carried out by modeling the various elements of cycle such as gas, compressor combustor, cooed gas turbine, HRSG steam turbine, condenser, etc. The performance is predicted for parameters such as fuel utilization efficiency (ηf), power-to-heat-ratio (PHR), coolant flow requirements, plant specific work, etc. as a function of independent parameters such as compressor pressure ratio (rpc) and turbine inlet temperature (TIT), etc. The results predicted will be helpful for designers to select the optimum compressor pressure ratio and TIT to achieve the target fuel utilization efficiency, and PHR at the target plant specific work.

Development of Air Cooled Combustor for Mitsubishi G Class Gas Turbine

2010 ◽  
Author(s):  
Keizo Tsukagoshi ◽  
Hisato Arimura ◽  
Katsunori Tanaka ◽  
Koichi Nishida ◽  
Testu Konishi ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Combined Cycle ◽  
Inlet Temperature ◽  
Air Cooling ◽  
Turbine Inlet Temperature ◽  
Steam Cooling ◽  
Cooling Technology ◽  
Verification Test

Mitsubishi Heavy Industries (MHI) pioneered the introduction of steam cooling technology for gas turbines with the introduction of the M501G in 1997. To date, 62 Mitsubishi G units have been sold making this series the largest steam cooled fleet in the market. The turbine inlet temperature (TIT) for this gas turbine is 1500 deg. C. The original M501G has been upgraded for air cooling applications. This upgraded version is called as M501GAC (G Air Cooled). Several Dry Low NOx (DLN) and cooling technologies from existing F and G series were applied to the upgraded M501GAC. The new GAC combustor was installed in the in-house verification Combined Cycle Power Plant, called T-Point, and verification tests of the combustor were conducted from November 2008. The air cooled M501GAC combustor demonstrated less than 15ppm NOx operation, stable combustor dynamics at all load levels, and high combustor ignition reliability making it suitable for daily start and stop operation at T-Point. Long term verification test is currently under way.

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