Introduction to the Comprex

1950 ◽  
Vol 17 (1) ◽  
pp. 47-53
Author(s):  
F. W. Barry
Keyword(s):  
Gas Turbine ◽  
Gas Flow ◽  
Pressure Ratio ◽  
Performance Characteristics ◽  
Simple Analysis ◽  
Compression And Expansion ◽  
Gas Turbine Cycle

Abstract This paper describes the construction and operation of a comprex, or pressure exchanger, together with its application to a gas-turbine cycle. A simple analysis is also developed, which is intended to indicate the performance characteristics of a comprex. This analysis shows that the pressure ratio, relative gas flow, and the ratio of the temperature of the leaving gas to that of the entering air are all functions of scavenging velocity and of the nature of the compression and expansion processes (as is shown graphically). Some irreversibility is found to be essential to the useful operation of a comprex. Finally, formulas for the major dimensions of a comprex are presented.

Recuperators in Gas Turbine Systems

1998 ◽  
Author(s):  
Esa Utriainen ◽  
Bengt Sundén
Keyword(s):  
Research And Development ◽  
Gas Turbine ◽  
Cross Sections ◽  
Heat Exchangers ◽  
Power Plants ◽  
Pressure Ratio ◽  
Compact Heat Exchangers ◽  
Thermodynamic Cycles ◽  
Large Pressure ◽  
Gas Turbine Cycle

The application of recuperators in advanced thermodynamic cycles is growing due to stronger demands of low emissions of pollutants and the necessity of improving the cycle efficiency of power plants to reduce the fuel consumption. This paper covers applications and types of heat exchangers used in gas turbine units. The trends of research and development are brought up and the future need for research and development is discussed. Material aspects are covered to some extent. Attempts to achieve compact heat exchangers for these applications are also discussed. With the increasing pressure ratio in the gas turbine cycle, large pressure differences between the hot and cold sides exist. This has to be accounted for. The applicability of CFD (Computational Fluid Dynamics) is discussed and a CFD–approach is presented for a specific recuperator. This recuperator has narrow wavy ducts with complex cross-sections and the hydraulic diameter is so small that laminar flow prevails. The thermal-hydraulic performance is of major concern.

Evaluation of the Compression-Intercooled Reheat-Gas-Turbine-Combined Cycle

1984 ◽  
Author(s):  
Ivan G. Rice
Keyword(s):  
Gas Turbine ◽  
Thermodynamic Analysis ◽  
Pressure Range ◽  
Pressure Ratio ◽  
Combined Cycle ◽  
Time Increase ◽  
Efficiency Loss ◽  
Gas Turbine Cycle ◽  
Cycle Efficiency ◽  
Turbine Output

Interest in the reheat-gas turbine (RHGT) as a way to improve combined-cycle efficiency is gaining momentum. Compression intercooling makes it possible to readily increase the reheat-gas-turbine cycle-pressure ratio and at the same time increase gas-turbine output; but at the expense of some combined-cycle efficiency and mechanical complexity. This paper presents a thermodynamic analysis of the intercooled cycle and pinpoints the proper intercooling pressure range for minimum combined-cycle-efficiency loss. At the end of the paper two-intercooled reheat-gas-turbine configurations are presented.

Combustion Chamber Steam Injection for Gas Turbine Performance Improvement During High Ambient Temperature Operations

2008 ◽  
Vol 130 (4) ◽  
Author(s):  
Abdallah Bouam ◽  
Slimane Aissani ◽  
Rabah Kadi
Keyword(s):  
Ambient Temperature ◽  
Combustion Chamber ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Large Scale ◽  
Pressure Ratio ◽  
Performance Testing ◽  
Steam Injection ◽  
Climatic Conditions ◽  
Gas Turbine Cycle

The gas turbines are generally used for large scale power generation. The basic gas turbine cycle has low thermal efficiency, which decreases in the hard climatic conditions of operation, so the cycles with thermodynamic improvement is found to be necessary. Among several methods shown their success in increasing the performances, the steam injected gas turbine cycle (STIG) consists of introducing a high amount of steam at various points in the cycle. The main purpose of the present work is to improve the principal characteristics of gas turbine used under hard condition of temperature in Algerian Sahara by injecting steam in the combustion chamber. The suggested method has been studied and compared to a simple cycle. Efficiency, however, is held constant when the ambient temperature increases from ISO conditions to 50°C. Computer program has been developed for various gas turbine processes including the effects of ambient temperature, pressure ratio, injection parameters, standard temperature, and combustion chamber temperature with and without steam injection. Data from the performance testing of an industrial gas turbine, computer model, and theoretical study are used to check the validity of the proposed model. The comparison of the predicted results to the test data is in good agreement. Starting from the advantages, we recommend the use of this method in the industry of hydrocarbons. This study can be contributed for experimental tests.

A Unique Approach for Thermo-Economic Optimization of an Intercooled, Reheat and Recuperated Gas Turbine for Cogeneration Applications

2001 ◽  
Author(s):  
R. Bhargava ◽  
A. Peretto
Keyword(s):  
Gas Turbine ◽  
Economic Performance ◽  
Performance Optimization ◽  
Pressure Ratio ◽  
Cost Structure ◽  
The Other ◽  
Specific Work ◽  
Sale Price ◽  
Wide Range ◽  
Gas Turbine Cycle

In the present paper, a comprehensive methodology for the thermo-economic performance optimization of an intercooled reheat (ICRH) gas turbine with recuperation for cogenerative applications has been presented covering a wide range of power-to-heat ratio values achievable. To show relative changes in the thermo-economic performance for the recuperated ICRH gas turbine cycle, results for ICRH, recuperated Brayton and simple Brayton cycles are also included in the paper. For the three load cases investigated, the recuperated ICRH gas turbine cycle provides the highest values of electric efficiency and Energy Saving Index for the cogenerative systems requiring low thermal loads (high power-to-heat ratio) compared to the other cycles. Also, this study showed, in general, that the recuperated ICRH cycle permits wider power-to-heat ratio range compared to the other cycles and for different load cases examined, a beneficial thermodynamic characteristic for the cogeneration applications. Furthermore, this study clearly shows that implementation of the recuperated ICRH cycle in a cogeneration system will permit to design a gas turbine which has the high specific work capacity and high electric efficiency at low value of the overall cycle pressure ratio compared to the other cycles studied. Economic performance of the investigated gas turbine cycles have been found dependent on the power-to-heat ratio value and the selected cost structure (fuel cost, electric sale price, steam sale price etc.), the results for a selected cost structure in the study are discussed in this paper.

Comparative Energy and Exergy Analysis of Proposed Gas Turbine Cycle With Simple Gas Turbine Cycle at Same Operational Cost

2019 ◽  
Author(s):  
M. N. Khan ◽  
Ibrahim M. Alarifi ◽  
I. Tlili
Keyword(s):  
Gas Turbine ◽  
Fuel Consumption ◽  
Exergy Analysis ◽  
Pressure Ratio ◽  
Specific Fuel Consumption ◽  
Exergy Destruction ◽  
Energy And Exergy ◽  
Energy And Exergy Analysis ◽  
Gas Turbine Cycle ◽  
The Impact

Abstract Environmentally friendly and effective power systems have been receiving increased investigation due to the aim of addressing global warming, energy expansion, and economic growth. Gas turbine cycles are perceived as a useful technology that has advanced power capacity. In this research, a gas turbine cycle has been proposed and developed from a simple and regenerative gas turbine cycle to enhance performance and reduce Specific fuel consumption. The impact of specific factors regarding the proposed gas turbine cycle on thermal efficiency, net output, specific fuel consumption, and exergy destruction, have been inspected. The assessments of the pertinent parameters were performed based on conventional thermodynamic energy and exergy analysis. The results obtained indicate that the peak temperature of the Proposed Gas Turbine Cycle increased considerably without affecting fuel consumption. The results show that at Pressure Ratio (rp = 6) the performance of the Proposed Gas Turbine Cycle is much better than Single Gas Turbine Cycle but the total exergy destruction of Proposed Gas Turbine Cycle higher than the SGTC.

Turbo-S.T.I.G.: The Turbocharged Steam Injected Gas Turbine Cycle

1989 ◽  
Author(s):  
R. W. Foster-Pegg
Keyword(s):  
Steam Turbine ◽  
Gas Turbine ◽  
Pressure Ratio ◽  
Complete Recovery ◽  
Back Pressure ◽  
Gas Turbine Combustor ◽  
Exhaust Heat ◽  
Pressure Steam ◽  
Cycle Maximum ◽  
Gas Turbine Cycle

In this Steam Injected Gas turbine cycle, maximum steam is raised with exhaust heat at the highest practical pressure for expansion in a back pressure steam turbine before injection into the gas turbine combustor. Additional steam is raised at lower pressure and injected into the combustor, to effect more complete recovery of heat. The back pressure steam turbine drives a topping air compressor which raises the gas cycle pressure ratio. This allows the standard gas turbine blading to accommodate the additional steam flow because of the higher pressure and density of the gas.

Using Staged Compression and Expansion to Enhance the Performance of a Gas Turbine Fuel Cell Hybrid System

2009 ◽  
Author(s):  
John VanOsdol ◽  
Edward L. Parsons
Keyword(s):  
Fuel Cell ◽  
Gas Turbine ◽  
Hybrid System ◽  
Cell Hybrid ◽  
Pressure Ratio ◽  
Heat Engine ◽  
Brayton Cycle ◽  
System Configuration ◽  
Compression And Expansion ◽  
Fuel Cell Hybrid

It has long been recognized that the heat generated from a solid oxide fuel cell (SOFC) is adequate to drive an external heat engine. The combination of the fuel cell plus the heat engine is called a gas turbine fuel cell hybrid power generation system. In most hybrid systems the heat engine consists of a single compressor and single turbine, arranged in either a Brayton cycle or a recuperated Brayton cycle. One characteristic of hybrid power cycles is that the compression costs are substantial. When this cycle is used in a coal fired hybrid system that is configured with an isolated anode stream to isolate and compress CO2, the work to compress the cathode air can greatly exceed the work to compress the CO2. It has also been shown for this same system that using intercooled compression for the cathode air reduces this compression cost. Since there have been no exhaustive studies performed which quantify these effects it is not clear exactly how much reduction in compression cost is possible. In this work we compare three hybrid systems. The first systems has a single compressor and turbine, run at a low pressure ratio as a recuperated Brayton cycle and at high pressure ratio as a simple Brayton cycle (see Figure 1). We then alter the recuperated Brayton cycle using both staged compression and staged expansion. The second system is thus configured with two compressors and two turbines. For this system an intercooler is placed between the compressors and the fuel cell stack is divided into two stacks each followed by a turbine (see Figure 3). Similarly the third system divides the compression and expansion legs of the cycle again into three compressors with intercoolers, and three fuel cell stacks each followed by its own turbine (see Figure 5). As the system configuration is altered by successive divisions of both the compression and expansion legs of the thermal heat engine cycle, the system configuration is transformed from a simple Brayton cycle to a staged approximation to an Ericsson cycle. We show that this new configuration for the gas turbine fuel cell hybrid system not only reduces the high cost of compression, but it makes more heat available for auxiliary system operations. In coal fired systems these auxiliary operations would include pre heating coal for the gasification system, reheating the syngas after cooling or even heating steam for a bottoming cycle.

The Optimum Pressure Ratio for a Combined Cycle Gas Turbine Plant

1995 ◽  
Vol 209 (4) ◽  
pp. 259-264 ◽  
Author(s):  
J H Horlock
Keyword(s):  
Gas Turbine ◽  
Pressure Ratio ◽  
Combined Cycle ◽  
Maximum Efficiency ◽  
Specific Work ◽  
Optimum Pressure ◽  
Turbine Plant ◽  
Gas Turbine Plant ◽  
Overall Efficiency ◽  
Gas Turbine Cycle

A graphical method of calculating the performance of gas turbine cycles, developed by Hawthorne and Davis (1), is adapted to determine the pressure ratio of a combined cycle gas turbine (CCGT) plant which will give maximum overall efficiency. The results of this approximate analysis show that the optimum pressure ratio is less than that for maximum efficiency in the higher level (gas turbine) cycle but greater than that for maximum specific work in that cycle. Introduction of reheat into the higher cycle increases the pressure ratio required for maximum overall efficiency.

Gas Turbines with Heat Exchanger and Water Injection in the Compressed Air

1970 ◽  
Vol 185 (1) ◽  
pp. 953-961 ◽  
Author(s):  
N Gašparović ◽  
J. G. Hellemans
Keyword(s):  
Heat Exchanger ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Pressure Ratio ◽  
Water Injection ◽  
Compressed Air ◽  
Specific Work ◽  
Turbine Inlet ◽  
Higher Temperature ◽  
Gas Turbine Cycle

Water injection into the compressed air between the compressor and the heat exchanger of a gas turbine plant represents only one of various possible methods of introducing water into a gas turbine cycle. With this process, it is advantageous to inject just sufficient water to produce saturation of the compressed air with water vapour. Assuming that the same size of heat exchanger is used, the following changes are introduced as compared with a gas turbine cycle without water injection. The efficiency is increased to an extent equivalent to raising the temperature at the turbine inlet by 100 degC. The gain in specific work is still greater. It attains values which can only be achieved with about 140 degC higher temperature at the turbine inlet. With a normal size of heat exchanger, the water consumption is about 6–8 per cent of the mass flow of air. This rate of consumption is not high enough to introduce any detrimental side effects in the cycle. Special water treatment is not necessary. The performance of existing designs or installations without a heat exchanger can be improved by adding a heat exchanger and water injection without necessitating any change in pressure ratio.

Performance Improvement of a Simple Gas Turbine Power Station Using Pulse Combustion Technology

2004 ◽  
Author(s):  
Mohamed A. Gadalla
Keyword(s):  
Gas Turbine ◽  
Thermal Efficiency ◽  
Pressure Ratio ◽  
Combustion Process ◽  
Pressure Rise ◽  
Operating Conditions ◽  
Maximum Pressure ◽  
Air Cooling ◽  
Pulse Combustion ◽  
Gas Turbine Cycle

The retrofitting projects have been considered in many countries to convert simple gas turbine units into more advanced cycle units with higher efficiency and higher output. Among many proven technologies, such as inlet air cooling, intercooling, regeneration, reheat and steam injection gas turbine etc., pulse combustion is one of the promising technologies in boosting both the output capacity and thermal efficiency, and reducing carbon and nitrogen oxides emissions without additional pollution control equipment. This paper presents the analysis of potential and real benefits of pulse combistion technology applied in the combustion process of a simple gas turbine cycle under different operating conditions. In addition, this study investigates the utilization of converting part of chemical energy of fuel into pressure energy in the gas turbine pulse combustion chamber. The influence of the maximum pressure rise due to pulse combustion (pre-compression parameter), the ratio of combustion heat released in the isochoric process, maximum cycle temperature, and compressor pressure ratio on the performance paramenters such as net work output, cycle thermal efficiency, and fuel consumption were also investigated. Finally, the results of comparative analyses between a simple gas turbine cycle utilizing a pulse combustor and a conventional cycle show the thermodynamic advantages of applying this technology in simple gas turbine power cycles.

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