Comparative Evaluation of Combined Cycles and Gas Turbine Systems With Water Injection, Steam Injection, and Recuperation

1995 ◽  
Vol 117 (1) ◽  
pp. 138-145 ◽  
Author(s):  
O. Bolland ◽  
J. F. Stadaas
Keyword(s):  
Gas Turbine ◽  
Water Injection ◽  
Steam Injection ◽  
Combined Cycle ◽  
Design Parameters ◽  
Turbine Engines ◽  
Turbine Engine ◽  
Turbine Cooling ◽  
Combined Cycles ◽  
Gas Turbine Cycle

Combined cycles have gained widespread acceptance as the most efficient utilization of the gas turbine for power generation, particularly for large plants. A variety of alternatives to the combined cycle that recover exhaust gas heat for re-use within the gas turbine engine have been proposed and some have been commercially successful in small to medium plants. Most notable have been the steam-injected, high-pressure aeroderivatives in sizes up to about 50 MW. Many permutations and combinations of water injection, steam injection, and recuperation, with or without intercooling, have been shown to offer the potential for efficiency improvements in certain ranges of gas turbine cycle design parameters. A detailed, general model that represents the gas turbine with turbine cooling has been developed. The model is intended for use in cycle analysis applications. Suitable choice of a few technology description parameters enables the model to represent accurately the performance of actual gas turbine engines of different technology classes. The model is applied to compute the performance of combined cycles as well as that of three alternatives. These include the simple cycle, the steam-injected cycle, and the dual-recuperated intercooled aftercooled steam-injected cycle (DRIASI cycle). The comparisons are based on state-of-the-art gas turbine technology and cycle parameters in four classes: large industrial (123–158 MW), medium industrial (38–60 MW), aeroderivatives (21–41 MW), and small industrial (4–6 MW). The combined cycle’s main design parameters for each size range are in the present work selected for computational purposes to conform with practical constraints. For the small systems, the proposed development of the gas turbine cycle, the DRIASI cycle, are found to provide efficiencies comparable or superior to combined cycles, and superior to steam-injected cycles. For the medium systems, combined cycles provide the highest efficiencies but can be challenged by the DRIASI cycle. For the largest systems, the combined cycle was found to be superior to all of the alternative gas turbine based cycles considered in this study.

scholarly journals Comparative Evaluation of Combined Cycles and Gas Turbine Systems With Water Injection, Steam Injection and Recuperation

1993 ◽  
Author(s):  
Olav Bolland ◽  
Jan Fredrik Stadaas
Keyword(s):  
Gas Turbine ◽  
Water Injection ◽  
Steam Injection ◽  
Combined Cycle ◽  
Design Parameters ◽  
Turbine Engines ◽  
Turbine Engine ◽  
Turbine Cooling ◽  
Combined Cycles ◽  
Gas Turbine Cycle

Combined cycles have gained widespread acceptance as the most efficient utilization of the gas turbine for power generation, particularly for large plants. A variety of alternatives to the combined cycle that recover exhaust gas heat for re-use within the gas turbine engine have been proposed and some have been commercially successful in small to medium plants. Most notable has been the steam injected, high-pressure aero-derivatives in sizes up to about 50 MW. Many permutations and combinations of water injection, steam injection, and recuperation, with or without intercooling, have been shown to offer the potential for efficiency improvements in certain ranges of gas turbine cycle design parameters. A detailed, general model that represents the gas turbine with turbine cooling has been developed. The model is intended for use in cycle analysis applications. Suitable choice of a few technology description parameters enables the model to accurately represent the performance of actual gas turbine engines of different technology classes. The model is applied to compute the performance of combined cycles as well as that of three alternatives. These include the simple cycle, the steam injected cycle and the dual-recuperated intercooled aftercooled steam injected cycle (DRIASI cycle). The comparisons are based on state-of-the-art gas turbine technology and cycle parameters in four classes: large industrial (123–158 MW), medium industrial (38–60 MW), aeroderivatives (21–41 MW) and small industrial (4–6 MW). The combined cycle’s main design parameters for each size range are in the present work selected for computational purposes to conform with practical constraints. For the small systems, the proposed development of the gas turbine cycle, the DRIASI cycle, are found to provide efficiencies comparable or superior to combined cycles, and superior to steam injected cycles. For the medium systems, combined cycles provide the highest efficiencies but can be challenged by the DRIASI cycle. For the largest systems, the combined cycle was found to be superior to all of the alternative gas turbine based cycles considered in this study.

scholarly journals Thermodynamic Analysis of Different Configurations of Combined Cycle Power Plants

2015 ◽  
Vol 5 (2) ◽  
pp. 89
Author(s):  
Munzer S. Y. Ebaid ◽  
Qusai Z. Al-hamdan
Keyword(s):  
Gas Turbine ◽  
Power Plants ◽  
Combined Cycle ◽  
Cycle Performance ◽  
Maximum Efficiency ◽  
Specific Work ◽  
Slight Effect ◽  
Turbine Engine ◽  
Gas Turbine Cycle ◽  
Cycle Efficiency

<p class="1Body">Several modifications have been made to the simple gas turbine cycle in order to increase its thermal efficiency but within the thermal and mechanical stress constrain, the efficiency still ranges between 38 and 42%. The concept of using combined cycle power or CPP plant would be more attractive in hot countries than the combined heat and power or CHP plant. The current work deals with the performance of different configurations of the gas turbine engine operating as a part of the combined cycle power plant. The results showed that the maximum CPP cycle efficiency would be at a point for which the gas turbine cycle would have neither its maximum efficiency nor its maximum specific work output. It has been shown that supplementary heating or gas turbine reheating would decrease the CPP cycle efficiency; hence, it could only be justified at low gas turbine inlet temperatures. Also it has been shown that although gas turbine intercooling would enhance the performance of the gas turbine cycle, it would have only a slight effect on the CPP cycle performance.</p>

scholarly journals An Optimizing Design Point Program for Selection of a Gas Turbine Cycle

1977 ◽  
Author(s):  
G. K. Conkol ◽  
T. Singh
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Design Parameters ◽  
Turbine Engines ◽  
Original Design ◽  
Ground Vehicle ◽  
Design Point ◽  
Optimizing Design ◽  
Volume Characteristics ◽  
Gas Turbine Cycle

As vehicles evolve through the concept phase, a wide variety of engines are usually considered. For long-life vehicles such as heavy armored tracked vehicles, gas turbines have been favored because of their weight and volume characteristics at high hp levels (1500 to 2000 hp). Many existing gas turbine engines, however, are undesirable for vehicular use because their original design philosophy was aircraft oriented. In a ground vehicle, mass flow and expense are only two areas in which these engines differ greatly. Because the designer generally is not given the freedom to design an engine from scratch, he must evaluate modifications of the basic Brayton cycle. In this study, various cycles are evaluated by using a design point program in order to optimize design parameters and to recommend a cycle for heavy vehicular use.

Cheng-Cycle Implementation on a Small Gas Turbine Engine

1984 ◽  
Vol 106 (3) ◽  
pp. 699-702 ◽  
Author(s):  
R. Digumarthi ◽  
Chung-Nan Chang
Keyword(s):  
Gas Turbine ◽  
Steam Injection ◽  
Injection System ◽  
Development Effort ◽  
Turbine Engine ◽  
Cycle System ◽  
Experimental Heat ◽  
Continuous Power ◽  
Design And Manufacture ◽  
Gas Turbine Cycle

The Cheng-Cycle turbine engine is a superheated steam injected gas turbine cycle system. This work is based on the Garrett 831 gas turbine. The development effort involved the design and manufacture of an experimental heat recovery steam generator, a steam injection system, and system controls. Measured performance data indicate the 26 percent efficiency improvement has been obtained compared to that of the basic turbine engine at its continuous power rating.

Technological Trend of Aircraft Gas Turbines and its Effect on the Development for Ship Propulsion Plants

1970 ◽  
Author(s):  
N. K. H. Scholz
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Pressure Ratio ◽  
Gas Turbine Engine ◽  
Design Parameters ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Compression Pressure ◽  
Turbine Engine ◽  
Ship Propulsion

The effect of the main design parameters of the aero gas turbine engine cycle, namely combustion temperature and compression pressure ratio, on the specific performance values is discussed. The resulting development trend has been of essential influence on the technology. Relevant approaches are outlined. The efforts relating to weight and manufacturing expense are also indicated. In the design of aero gas turbine engines increasing consideration is given to the specific flight mission requirements, such as for instance by the introduction of the by-pass principle. Therefore direct application of aero gas turbine engines for ship propulsion without considerable modifications, as has been practiced in the past, is not considered very promising for the future. Nevertheless, there are possibilities to take advantage of aero gas turbine engine developments for ship propulsion systems. Appropriate approaches are discussed. With the experience obtained from aero gas turbine engines that will enter service in the early seventies it should be possible to develop marine gas turbine engines achieving consumptions and lifes that are competitive with those of advanced diesel units.

The Performance Analysis of a Combined Power Plant Implementing Technologies for Enhancing Power and Efficiency

2015 ◽  
Author(s):  
Jumok Won ◽  
Changmin Son ◽  
Changju Kim
Keyword(s):  
Gas Turbine ◽  
Cooling System ◽  
Promising Result ◽  
Load Condition ◽  
Steam Injection ◽  
Combined Cycle ◽  
Inlet Temperature ◽  
Net Benefit ◽  
Turbine Cooling ◽  
The Difference

Combined Cycle Power (CCP) plant using Liquefied Natural Gas (LNG) plays a key role in electric supply including nuclear and coal power generation systems. There is growing demand for enhancing power and efficiency of existing CCP plants. Typically, the power reduction of gas turbine during summer can be recovered if gas turbine intake cooling system can be implemented in existing LNG based CCP plants. Possible approaches for power and efficiency enhancement are being widely studied in global gas turbine society. The present study aims to investigate net benefit of implementing selected technologies for enhancing power and efficiency of an existing LNG based CCP. For a comparative study, selected technologies such as (1) gas turbine intake cooling system, (2) wet cycle (steam injection), and (3) turbine cooling air precooling are implemented to Busan LNG based CCP plant, Republic of Korea. The complete CCP plant is modeled using Gatecycle and its validation against field operation data showed the differences in the generated power and efficiency at the base load condition within 0.5% and the difference in the turbine inlet temperature value less than 3%. Among the selected technologies, the wet cycle (steam injection) showed the most promising result. Its system composition is relatively simple in comparison to the other technologies. Furthermore, it is advantageous to use within a reasonable limit when higher power is required for peak demand of electric power.

Research on Thermal Efficiencies of Various Power Cycles for GFRs and VHTRs

2018 ◽  
Author(s):  
Mohammed Mahdi ◽  
Roman Popov ◽  
Igor Pioro
Keyword(s):  
Gas Turbine ◽  
Heavy Water ◽  
Nuclear Power ◽  
Power Plants ◽  
Supercritical Pressure ◽  
Combined Cycle ◽  
Power Cycles ◽  
Power Cycle ◽  
Combined Cycles ◽  
Gas Turbine Cycle

The vast majority of Nuclear Power Plants (NPPs) are equipped with water- and heavy-water-cooled reactors. Such NPPs have lower thermal efficiencies (30–36%) compared to those achieved at NPPs equipped with Advanced Gas-cooled Reactors (AGRs) (∼42%) and Sodium-cooled Fast Reactors (SFRs) (∼40%), and, especially, compared to those of modern advanced thermal power plants, such as combined cycle with thermal efficiencies up to 62% and supercritical-pressure coal-fired power plants — up to 55%. Therefore, NPPs with water- and heavy-water-cooled reactors are not very competitive with other power plants. Therefore, this deficiency of current water-cooled NPPs should be addressed in the next generation or Generation-IV nuclear-power reactors / NPPs. Very High Temperature Reactor (VHTR) concept / NPP is currently considered as the most efficient NPP of the next generation. Being a thermal-spectrum reactor, VHTR will use helium as a reactor coolant, which will be heated up to 1000°C. The use of a direct Brayton helium-turbine cycle was considered originally. However, technical challenges associated with the direct helium cycle have resulted in a change of the reference concept to indirect power cycle, which can be also a combined cycle. Along with the VHTR, Gas-cooled Fast Reactor (GFR) concept / NPP is also regarded as one of the most thermally efficient concept for the upcoming generation of NPPs. This concept was also originally thought to be with the direct helium power cycle. However, technical challenges have changed the initial idea of power cycle to a number of options including indirect Brayton cycle with He-N2 mixture, application of SuperCritical (SC)-CO2 cycles or combined cycles. The objective of the current paper is to provide the latest information on new developments in power cycles proposed for these two helium-cooled Generation-IV reactor concepts, which include indirect nitrogen-helium Brayton gas-turbine cycle, supercritical-pressure carbon-dioxide Brayton gas-turbine cycle, and combined cycles. Also, a comparison of basic thermophysical properties of helium with those of other reactor coolants, and with those of nitrogen, nitrogen-helium mixture and SC-CO2 is provided.

Semi-Closed Gas Turbine/Combined Cycle With Water Recovery and Extensive Exhaust Gas Recirculation

1996 ◽  
Author(s):  
Bruno Facchini ◽  
Daniele Fiaschi ◽  
Giampaolo Manfrida
Keyword(s):  
Gas Turbine ◽  
Water Injection ◽  
Combined Cycle ◽  
Point Of View ◽  
Exhaust Gas ◽  
Water Recovery ◽  
Gas Treatment ◽  
High Level ◽  
Gas Recirculation ◽  
Gas Turbine Cycle

This innovative gas turbine cycle can offer several advantages over conventional cycles from the point of view of environmental friendship. The basic idea of SCGT/CC (Semi-Closed Gas Turbine/Combined Cycle with water recovery) is to cool down the exhaust temperatures to allow full condensation of the water vapor, and recirculate a large part of the exhaust gases to the compressor. The condensed water can then be reinjected by means of a pump at compressor delivery. The working gas composition is thus close to that corresponding to stoichiometric combustion, which opens the possibility of applying techniques for CO2 recycling and general exhaust gas treatment. An increase in work output is connected to water injection, while a high level of efficiency is maintained as the compressor work is reduced and the cycle parameters are tuned for the exhaust of this turbine.

Off-Design Analysis of the Semi Closed Gas Turbine Cycle (SCGT) With Low CO2 Emissions

2006 ◽  
Author(s):  
Daniele Fiaschi ◽  
Federico Scatragli
Keyword(s):  
Gas Turbine ◽  
Water Injection ◽  
Steam Pressure ◽  
Design Analysis ◽  
Combined Cycle ◽  
Co2 Removal ◽  
Open Cycle ◽  
Gas Turbine Cycle ◽  
Compressor Efficiency ◽  
Working Point

The Semi Closed Gas Turbine Cycle (SCGT) was introduced as a short to medium term solution for applying existing CO2 removal techniques to current production gas turbine powerplants. Thus, one of the main goals is the adaptability to existing turmomachinery, with only minor changes to the equipment. In this manuscript, the off–design analysis of two previously proposed and thermodynamically assessed configurations was carried out: the first one is the combined cycle (SCGT/CC), related to an heavy duty gas turbine, whereas the second one is the recuperative–evaporative cycle (SCGT/RE). Both of them may be equipped with intercooled or, either, aftercooled compression, which is done with spray water injection. The analysis was carried out with special reference to the off design conditions of the compressor and to its coupling with turbine when the partial exhausts recirculation is applied to originally open cycle GTs. In the SCGT/CC configurations, the steam pressure levels are increased due to the increased GT exhausts temperature with respect to the open cycle. When no water injection is applied, the working point of the compressor due to the different gas composition and temperature are largely within the operating margins, thus the semi closed configuration may be applied even to compressors with reduced stall bounds and no large decays in compressor efficiency were found compared to the design operation. On the contrary, when water injection is applied, heavy variations of the compressor working point were found, which make the effects of exhausts recirculation comparatively marginal and leads to unavoidable compressor efficiency drop. It suggests that the application of water injection may be suitable only for the short peakload times, whereas current technology allows the shifting to SCGT.

Performance Levels Obtainable From Steam-Gas Turbine Combined Cycles

1988 ◽  
Author(s):  
G. Negri di Montenegro ◽  
R. Bettocchi ◽  
G. Cantore ◽  
G. Naldi
Keyword(s):  
Gas Turbine ◽  
Combined Cycle ◽  
Specific Work ◽  
Plant Design ◽  
General Study ◽  
Improve Performance ◽  
Efficiency Increase ◽  
Combined Cycles ◽  
Overall Efficiency ◽  
Gas Turbine Cycle

This study aims at the evaluation of the best performance obtainable from steam-gas turbine combined plants both in a new plant design and in improving existing steam plants by adding a topping gas turbine system. A method of comparison is presented here, based on the choice of a steam-gas reference cycle which has shown to be particularly suitable for a general study. A thermodynamic analysis has been carried out showing the influence on the combined plant overall efficiency of the parameters characterizing both the gas and steam cycles. The reference cycle as well as those derivable from it by modifying the gas portion cycle only has been studied. The analysis was also extended to evaluation of the gas to steam units output power ratio and of the efficiency increase when repowering a steam unit. It has been shown that the combined cycle plants maximum overall-efficiency is achieved, whatever the steam cycle, when the gas turbine cycle operates at maximum specific work. The result is that the best performance in combined cycle plants is achived by using multiple expansion with reheating in the gas cycle, when designing a new plant. When steam plants are to be repowered by means of existing gas turbine units, afterburning may be useful to improve performance.

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