scholarly journals Potentials for Pressure Gain Combustion in Advanced Gas Turbine Cycles

2019 ◽  
Vol 9 (16) ◽  
pp. 3211
Author(s):  
Nicolai Neumann ◽  
Dieter Peitsch
Keyword(s):  
Gas Turbine ◽  
Thermal Efficiency ◽  
Specific Work ◽  
Turbine Cooling ◽  
Turbine Efficiency ◽  
Optimization Study ◽  
Pressure Gain Combustion ◽  
Reduce Emissions ◽  
Secondary Air ◽  
Gas Turbine Cycle

Pressure gain combustion evokes great interest as it promises to increase significantly gas turbine efficiency and reduce emissions. This also applies to advanced thermodynamic cycles with heat exchangers for intercooling and recuperation. These cycles are superior to the classic Brayton cycle and deliver higher specific work and/or thermal efficiency. The combination of this revolutionary type of combustion in an intercooled or recuperated gas turbine cycle can, however, lead to even higher efficiency or specific work. The research of these potentials is the topic of the presented paper. For that purpose, different gas turbine setups for intercooling, recuperation, and combined intercooling and recuperation are modeled in a gas turbine performance code. A secondary air system for turbine cooling is incorporated, as well as a blade temperature evaluation. The pressure gain combustion is represented by analytical-algebraic and empirical models from the literature. Key gas turbine specifications are then subject to a comprehensive optimization study, in order to identify the design with the highest thermal efficiency. The results indicate that the combination of intercooling and pressure gain combustion creates synergies. The thermal efficiency is increased by 10 percentage points compared to a conventional gas turbine with isobaric combustion.

Pulsed Impingement Turbine Cooling and its Effect on the Efficiency of Gas Turbines With Pressure Gain Combustion

2020 ◽  
Author(s):  
Nicolai Neumann ◽  
Dieter Peitsch ◽  
Arne Berthold ◽  
Frank Haucke ◽  
Panagiotis Stathopoulos
Keyword(s):  
Gas Turbine ◽  
Thermal Efficiency ◽  
Gas Turbines ◽  
Turbine Blades ◽  
Impingement Cooling ◽  
Turbine Cooling ◽  
Pressure Gain Combustion ◽  
Cooling Air ◽  
Gas Turbine Cycle ◽  
Cycle Efficiency

Abstract Performance improvements of conventional gas turbines are becoming increasingly difficult and costly to achieve. Pressure Gain Combustion (PGC) has emerged as a promising technology in this respect, due to the higher thermal efficiency of the respective ideal gas turbine cycle. Previous cycle analyses considering turbine cooling methods have shown that the application of pressure gain combustion may require more turbine cooling air. This has a direct impact on the cycle efficiency and reduces the possible efficiency gain that can potentially be harvested from the new combustion technology. Novel cooling techniques could unlock an existing potential for a further increase in efficiency. Such a novel turbine cooling approach is the application of pulsed impingement jets inside the turbine blades. In the first part of this paper, results of pulsed impingement cooling experiments on a curved plate are presented. The potential of this novel cooling approach to increase the convective heat transfer in the inner side of turbine blades is quantified. The second part of this paper presents a gas turbine cycle analysis where the improved cooling approach is incorporated in the cooling air calculation. The effect of pulsed impingement cooling on the overall cycle efficiency is shown for both Joule and PGC cycles. In contrast to the authors’ anticipation, the results suggest that for relevant thermodynamic cycles pulsed impingement cooling increases the thermal efficiency of Joule cycles more significantly than it does in the case of PGC cycles. Thermal efficiency improvements of 1.0 p.p. for pure convective cooling and 0.5 p.p. for combined convective and film with TBC are observed for Joule cycles. But just up to 0.5 p.p. for pure convective cooling and 0.3 p.p. for combined convective and film cooling with TBC are recorded for PGC cycles.

Pulsed Impingement Turbine Cooling and Its Effect on the Efficiency of Gas Turbines With Pressure Gain Combustion

2021 ◽  
Vol 143 (7) ◽  
Author(s):  
Nicolai Neumann ◽  
Arne Berthold ◽  
Frank Haucke ◽  
Dieter Peitsch ◽  
Panagiotis Stathopoulos
Keyword(s):  
Gas Turbine ◽  
Thermal Efficiency ◽  
Gas Turbines ◽  
Turbine Blades ◽  
Impingement Cooling ◽  
Turbine Cooling ◽  
Pressure Gain Combustion ◽  
Cooling Air ◽  
Gas Turbine Cycle ◽  
Cycle Efficiency

Abstract Performance improvements of conventional gas turbines are becoming increasingly difficult and costly to achieve. Pressure gain combustion (PGC) has emerged as a promising technology in this respect, due to the higher thermal efficiency of the respective ideal gas turbine cycle. Previous cycle analyses considering turbine cooling methods have shown that the application of pressure gain combustion may require more turbine cooling air. This has a direct impact on the cycle efficiency and reduces the possible efficiency gain that can potentially be harvested from the new combustion technology. Novel cooling techniques could unlock an existing potential for a further increase in efficiency. Such a novel turbine cooling approach is the application of pulsed impingement jets inside the turbine blades. In the first part of this paper, results of pulsed impingement cooling experiments on a curved plate are presented. The potential of this novel cooling approach to increase the convective heat transfer in the inner side of turbine blades is quantified. The second part of this paper presents a gas turbine cycle analysis where the improved cooling approach is incorporated in the cooling air calculation. The effect of pulsed impingement cooling on the overall cycle efficiency is shown for both Joule and PGC cycles. In contrast to the authors’ anticipation, the results suggest that for relevant thermodynamic cycles pulsed impingement cooling increases the thermal efficiency of Joule cycles more significantly than it does in the case of PGC cycles. Thermal efficiency improvements of 1.0 p.p. for pure convective cooling and 0.5 p.p. for combined convective and film with TBC are observed for Joule cycles. But just up to 0.5 p.p. for pure convective cooling and 0.3 p.p. for combined convective and film cooling with TBC are recorded for PGC cycles.

A Reevaluation of the Holzwarth Gas Turbine Cycle for Use in Small Power Plants

2001 ◽  
Author(s):  
Osvaldo José Venturini ◽  
Sebastião Varella
Keyword(s):  
Gas Turbine ◽  
Temperature Variation ◽  
Thermal Efficiency ◽  
Power Plants ◽  
Constant Pressure ◽  
Specific Work ◽  
Brayton Cycle ◽  
Small Power ◽  
The One ◽  
Gas Turbine Cycle

The purpose of this work is to analyze a gas turbine working under a cycle similar to the one proposed, by the Dr. Holtzwarth, at the beginning of the last century, showing its potentiality, mainly when applied to small power turbines. The method for analysis is based in the quasi-steady thermodynamic equilibrium principle, where the effects of the pressure and temperature variation, due to the intermittent combustion, are considered. Conclusions are presented considering the increase of the thermal efficiency and the available specific work, resulting from the constant volume combustion, when compared with those of a turbine operating under constant pressure combustion (Brayton Cycle). These results are obtained using actual curves of operation for the compressor and the turbine and, as well as, the “matching” of them.

Analysis of a Basic Chemically Recuperated Gas Turbine Power Plant

1994 ◽  
Vol 116 (2) ◽  
pp. 277-284 ◽  
Author(s):  
K. F. Kesser ◽  
M. A. Hoffman ◽  
J. W. Baughn
Keyword(s):  
Gas Turbine ◽  
Thermal Efficiency ◽  
Waste Heat ◽  
Computer Code ◽  
Combined Cycle ◽  
Specific Work ◽  
Turbine Cooling ◽  
Specific Heats ◽  
Methane Steam ◽  
Cooling Air

This paper investigates a “basic” Chemically Recuperated Gas Turbine (a “basic” CRGT is defined here to be one without intercooling or reheat). The CRGT is of interest due to its potential for ultralow NOx emissions. A computer code has been developed to evaluate the performance characteristics (thermal efficiency and specific work) of the Basic CRGT, and to compare it to the steam-injected gas turbine (STIG), the combined cycle (CC) and the simple cycle gas turbine (SC) using consistent assumptions. The CRGT model includes a methane-steam reformer (MSR), which converts a methane-steam mixture into a hydrogen-rich fuel using the “waste” heat in the turbine exhaust. Models for the effects of turbine cooling air, variable specific heats, and the real gas effects of steam are included. The calculated results show that the Basic CRGT has a thermal efficiency higher than the STIG and simple cycles but not quite as high as the combined cycle.

Sensitivity Analysis of a SOFC-GT Based Power Cycle

2008 ◽  
Author(s):  
Farshid Zabihian ◽  
Alan S. Fung ◽  
Murat Koksal ◽  
Shakil Malek ◽  
Moftah Elhebshi
Keyword(s):  
Sensitivity Analysis ◽  
Natural Gas ◽  
Gas Turbine ◽  
Thermal Efficiency ◽  
Macro Level ◽  
Specific Work ◽  
Utilization Factor ◽  
Turbine Efficiency ◽  
Ohmic Losses ◽  
Mathematical Expressions

This paper presents the sensitivity analysis of tubular Solid Oxide Fuel Cell (SOFC) stacks. The macro level modelling implemented in AspenPlus™ for the simulation of hybrid SOFC-gas turbine systems. The macro level thermodynamic first law analysis was previously performed on the same model. This sensitivity analysis is the continuation towards investigating the effects of different fuel compositions and turbine and compressor efficiencies on cycle efficiency and other parameters. The model is 0-dimensional, can accept hydrocarbon fuels with user inputs of current density, fuel and air composition, flow rates, temperature, pressure and fuel utilization factor. The model outputs the composition of the exhaust, work produced, heat available for reformer, etc. The model was developed considering the activation, concentration and ohmic losses within SOFC and mathematical expressions for these were chosen based on available studies in recent literatures. In this paper different fuels such as reformed natural gas, biogas with different compositions are considered to investigate the effect of fuel composition on the performance of the hybrid SOFC-gas turbine systems. In order to monitor the performance of the system parameters such as thermal efficiency, cycle specific work, SOFC specific work, gas turbine specific work, and work ratio (SOFC work / gas turbine work) are investigated. Furthermore, for specific fuel the effect of turbine and compressor efficiencies on system’s overall performance are studied for entire range from 50% to 100%, keeping gas turbine efficiency constant and increasing compressor efficiency by 5% and vice versa. For instance, if the fuel is switched from natural gas (with 100% CH4) to biogas (with the composition of 70% CH4, 25% CO2 and 5% H2) and the other parameters are kept constant (isentropic efficiency 85% for both turbine and compressor) the overall thermal efficiency will decrease by 1.4%, whereas the cycle specific work will increase by 36.7%. In addition, the work ratio will increase by 25.1% showing that more power is generated in SOFC in comparison to gas turbine. In addition, if the efficiency of turbine and compressor increase from 85% to 90%, the efficiency and cycle specific work of the system will increase by 3.1% and 3%, respectively whereas, the work ratio will decrease by 5.6%, due to the more power generated in gas turbine.

scholarly journals Comprehensive Thermodynamic Analysis of the Humphrey Cycle for Gas Turbines with Pressure Gain Combustion

Energies ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 3521 ◽  
Author(s):  
Panagiotis Stathopoulos
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Combustion Process ◽  
Ideal Gas ◽  
Point Of View ◽  
Pressure Gain Combustion ◽  
Combustion Technology ◽  
Secondary Air ◽  
And Performance ◽  
The Impact

Conventional gas turbines are approaching their efficiency limits and performance gains are becoming increasingly difficult to achieve. Pressure Gain Combustion (PGC) has emerged as a very promising technology in this respect, due to the higher thermal efficiency of the respective ideal gas turbine thermodynamic cycles. Up to date, only very simplified models of open cycle gas turbines with pressure gain combustion have been considered. However, the integration of a fundamentally different combustion technology will be inherently connected with additional losses. Entropy generation in the combustion process, combustor inlet pressure loss (a central issue for pressure gain combustors), and the impact of PGC on the secondary air system (especially blade cooling) are all very important parameters that have been neglected. The current work uses the Humphrey cycle in an attempt to address all these issues in order to provide gas turbine component designers with benchmark efficiency values for individual components of gas turbines with PGC. The analysis concludes with some recommendations for the best strategy to integrate turbine expanders with PGC combustors. This is done from a purely thermodynamic point of view, again with the goal to deliver design benchmark values for a more realistic interpretation of the cycle.

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>

Pressure Gain Combustion Application to Marine and Industrial Gas Turbines

2012 ◽  
Author(s):  
Philip H. Snyder ◽  
M. Razi Nalim
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Technology Development ◽  
Innovative Technology ◽  
Turbine Engines ◽  
Specific Work ◽  
Compression Pressure ◽  
Pressure Gain Combustion ◽  
Industrial Gas Turbines ◽  
Incremental Improvement

Renewed interest in pressure gain combustion applied as a replacement of conventional combustors within gas turbine engines creates the potential for greatly increased capability engines in the marine power market segment. A limited analysis has been conducted to estimate the degree of improvements possible in engine thermal efficiency and specific work for a type of wave rotor device utilizing these principles. The analysis considers a realistic level of component losses. The features of this innovative technology are compared with those of more common incremental improvement types of technology for the purpose of assessing potentials for initial market entry within the marine gas turbine market. Both recuperation and non-recuperation cycles are analyzed. Specific fuel consumption improvements in excess of 35% over those of a Brayton cycle are indicated. The technology exhibits the greatest percentage potential in improving efficiency for engines utilizing relatively low or moderate mechanical compression pressure ratios. Specific work increases are indicated to be of an equally dramatic magnitude. The advantages of the pressure gain combustion approach are reviewed as well as its technology development status.

scholarly journals Energy and Exergy Analysis of a Simple Gas Turbine Cycle with Wet Compression

2018 ◽  
Vol 8 (1) ◽  
pp. 30 ◽  
Author(s):  
E. H. Betelmal ◽  
S. A. Farhat
Keyword(s):  
Gas Turbine ◽  
Water Injection ◽  
Analytical Formula ◽  
Heat Rate ◽  
Performance Model ◽  
Exergy Destruction ◽  
Isentropic Compression ◽  
Turbine Efficiency ◽  
Wet Compression ◽  
Gas Turbine Cycle

A thermodynamic model of the wet compressor in a simple gas turbine cycle was investigated in this paper. A suitable quantity of water was injected into the compressor-stages where it evaporated. Subsequently, the steam and air were heated in the combustion chamber and expanded in the turbine. The wet compressor (WC) has become a reliable way to reduce gas emissions and increase gas turbine efficiency. In this study, the operational data of the simple gas turbine and the maximum amount of water that can be injected into the compressor were assessed, as well as a comparison between the dry compression, the wet compression and the isentropic compression. The performance variation due to water spray in the compressor and the effect of varying ambient temperature on the performance of gas turbine (thermal efficiency, power) was investigated, and the results are compared to the results of the same cycle with a dry compressor. The analytical formula of exergy destruction and results show that exergy destruction increases with water injection. The programming of the performance model for the gas turbine was developed utilizing the software IPSEpro. The results of the gas turbine with a wet compressor demonstrates a 12% reduction in the compressor exit temperature up to isentropic temperature. The compressor work decreased by 11% when using a wet compressor, this lead to an improvement in power output and efficiency However, the wet compressor increases the specific fuel consumption and heat rate of the gas turbine. There are limitations in the amount of steam that can be injected, 0.4 kg/s of water was the optimum amount injected into the compressor.

Effect of the Environmental Conditions of Tropical Climates on the Performance Parameters of a Gas Turbine Power Generation Plant

2020 ◽  
Author(s):  
J. Fajardo ◽  
D. Barreto ◽  
T. Castro ◽  
I. Baldiris
Keyword(s):  
Power Plant ◽  
Relative Humidity ◽  
Gas Turbine ◽  
Output Power ◽  
High Temperatures ◽  
Environmental Conditions ◽  
Thermal Efficiency ◽  
Specific Work ◽  
Atmospheric Conditions ◽  
Compressor Inlet

Abstract It is known that high temperatures adversely affect the performance of gas turbines, but the effect of the combination of atmospheric conditions (temperature and relative humidity -RH-) on the operation of this type of system is unknown. In this work the effects of atmospheric conditions on the energy and exergy indicators of a power plant with gas turbine were studied. The indicators studied were the mass flow, the specific work consumed by the compressor, specific work produced by the turbine, the combustion gas temperature, the NO concentration, the net output power, the thermal efficiency, the heat rate, the specific consumption of fuel, the destruction of exergy and exergy efficiency. Among the results, it is noted that for each degree celsius that reduces the temperature of the air at the compressor inlet at constant relative humidity on average, the mass flow of dry air increases by 0.27 kg/s, the specific work consumed by the compressors decreases by 0.45%, the output power increases by 1.17% and the thermal efficiency increases by 0.8%, the exergy destruction increases by 0.72% and the exergy efficiency increases by 0.81%. In addition, humidity changes relative to high temperatures are detected more significantly than at low temperatures. The power plant studied is installed in Cartagena, Colombia and since it is not operating in the design environmental conditions (15 °C and 60% relative humidity) it experiences a loss of output power of 6140 kW and a drop in thermal efficiency of 5.12 %. These results allow considering the implementation of air cooling technologies at the compressor inlet to compensate for the loss of power at atmospheric air conditions.

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