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1
Kosowski, Krzysztof, e Marian Piwowarski. "Design Analysis of Micro Gas Turbines in Closed Cycles". Energies 13, n. 21 (5 novembre 2020): 5790. http://dx.doi.org/10.3390/en13215790.
Testo completoAbstract (sommario):
The problems faced by designers of micro-turbines are connected with a very small volume flow rate of working media which leads to small blade heights and a high rotor speed. In the case of gas turbines this limitation can be overcome by the application of a closed cycle with very low pressure at the compressor inlet (lower than atmospheric pressure). In this way we may apply a micro gas turbine unit of accepted efficiency to work in a similar range of temperatures and the same pressure ratios, but in the range of smaller pressure values and smaller mass flow rate. Thus, we can obtain a gas turbine of a very small output but of the efficiency typical of gas turbines with a much higher power. In this paper, the results of the thermodynamic calculations of the turbine cycles are discussed and the designed gas turbine flow parts are presented. Suggestions of the design solutions of micro gas turbines for different values of power output are proposed. This new approach to gas turbine arrangement makes it possible to build a gas turbine unit of a very small output and a high efficiency. The calculations of cycle and gas turbine design were performed for different cycle parameters and different working media (air, nitrogen, hydrogen, helium, xenon and carbon dioxide).
2
Moukalled, F., e I. Lakkis. "Computer-Aided Analysis of Gas Turbine Cycles". International Journal of Mechanical Engineering Education 22, n. 3 (luglio 1994): 209–27. http://dx.doi.org/10.1177/030641909402200306.
Testo completoAbstract (sommario):
This paper describes a microcomputer-based, interactive, and menu-driven software package designed to help mechanical engineering students to understand gas turbines and to allow them to conduct more analysis of gas turbine cycles than they would normally be able to do by hand-calculation. The program deals with gas turbine cycle analysis so the acronym GTCA is used. GTCA is written in the Pascal computer language and runs on IBM PC, or compatible, computers. Improvements to the basic Brayton cycle, including three compressor and turbine stages, reheater, heat exchanger, intercooler, and precooler are incorporated into the program. The package is highly flexible and allows the user to model cycle schemes formed of any combination of these elements and to handle both shaft power turbines and aircraft turbojet and turbofan turbines. An important feature of the program is its ability to solve for any unknown variables. In addition to this, the program provides a schematic of the turbine plant layout and a temperature-entropy diagram of the cycle, and permits the plotting of the variation of any quantity versus any other quantity. This option enables the student to easily study and understand the effects of changing design variables on the overall performance of the cycle and permits its optimization. The statistical survey conducted along with the examples presented demonstrate the capabilities of the package as a teaching tool.
3
Kosowski, Krzysztof, Karol Tucki, Marian Piwowarski, Robert Stępień, Olga Orynycz e Wojciech Włodarski. "Thermodynamic Cycle Concepts for High-Efficiency Power Plants. Part B: Prosumer and Distributed Power Industry". Sustainability 11, n. 9 (9 maggio 2019): 2647. http://dx.doi.org/10.3390/su11092647.
Testo completoAbstract (sommario):
An analysis was carried out for different thermodynamic cycles of power plants with air turbines. A new modification of a gas turbine cycle with the combustion chamber at the turbine outlet has been described in the paper. A special air by-pass system of the combustor was applied, and in this way, the efficiency of the turbine cycle was increased by a few points. The proposed cycle equipped with an effective heat exchanger could have an efficiency higher than a classical gas turbine cycle with a regenerator. Appropriate cycle and turbine calculations were performed for micro power plants with turbine output in the range of 10–50 kW. The best arrangements achieved very high values of overall cycle efficiency, 35%–39%. Such turbines could also work in cogeneration and trigeneration arrangements, using various fuels such as liquids, gaseous fuels, wastes, coal, or biogas. Innovative technology in connection with ecology and the failure-free operation of the power plant strongly suggests the application of such devices at relatively small generating units (e.g., “prosumers” such as home farms and individual enterprises), assuring their independence from the main energy providers. Such solutions are in agreement with the politics of sustainable development.
4
Sanaye, Sepehr, e Salahadin Hosseini. "Off-design performance improvement of twin-shaft gas turbine by variable geometry turbine and compressor besides fuel control". Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy 234, n. 7 (3 dicembre 2019): 957–80. http://dx.doi.org/10.1177/0957650919887888.
Testo completoAbstract (sommario):
A novel procedure for finding the optimum values of design parameters of industrial twin-shaft gas turbines at various ambient temperatures is presented here. This paper focuses on being off design due to various ambient temperatures. The gas turbine modeling is performed by applying compressor and turbine characteristic maps and using thermodynamic matching method. The gas turbine power output is selected as an objective function in optimization procedure with genetic algorithm. Design parameters are compressor inlet guide vane angle, turbine exit temperature, and power turbine inlet nozzle guide vane angle. The novel constrains in optimization are compressor surge margin and turbine blade life cycle. A trained neural network is used for life cycle estimation of high pressure (gas generator) turbine blades. Results for optimum values for nozzle guide vane/inlet guide vane (23°/27°–27°/6°) in ambient temperature range of 25–45 ℃ provided higher net power output (3–4.3%) and more secured compressor surge margin in comparison with that for gas turbines control by turbine exit temperature. Gas turbines thermal efficiency also increased from 0.09 to 0.34% (while the gas generator turbine first rotor blade creep life cycle was kept almost constant about 40,000 h). Meanwhile, the averaged values for turbine exit temperature/turbine inlet temperature changed from 831.2/1475 to 823/1471°K, respectively, which shows about 1% decrease in turbine exit temperature and 0.3% decrease in turbine inlet temperature.
5
Langston, Lee S. "Whisper and Roar". Mechanical Engineering 136, n. 07 (1 luglio 2014): 38–43. http://dx.doi.org/10.1115/1.2014-jul-2.
Testo completoAbstract (sommario):
This article focuses on the use of gas turbines for electrical power, mechanical drive, and marine applications. Marine gas turbines are used to generate electrical power for propulsion and shipboard use. Combined-cycle electric power plants, made possible by the gas turbine, continue to grow in size and unmatched thermal efficiency. These plants combine the use of the gas turbine Brayton cycle with that of the steam turbine Rankine cycle. As future combined cycle plants are introduced, we can expect higher efficiencies to be reached. Since almost all recent and new U.S. electrical power plants are powered by natural gas-burning, high-efficiency gas turbines, one has solid evidence of their contribution to the greenhouse gas reduction. If coal-fired thermal power plants, with a fuel-to-electricity efficiency of around 33%, are swapped out for combined-cycle power plants with efficiencies on the order of 60%, it will lead to a 70% reduction in carbon emissions per unit of electricity produced.
6
Maunsbach, K., A. Isaksson, J. Yan, G. Svedberg e L. Eidensten. "Integration of Advanced Gas Turbines in Pulp and Paper Mills for Increased Power Generation". Journal of Engineering for Gas Turbines and Power 123, n. 4 (1 gennaio 2001): 734–40. http://dx.doi.org/10.1115/1.1359773.
Testo completoAbstract (sommario):
The pulp and paper industry handles large amounts of energy and today produces the steam needed for the process and some of the required electricity. Several studies have shown that black liquor gasification and combined cycles increase the power production significantly compared to the traditional processes used today. It is of interest to investigate the performance when advanced gas turbines are integrated with next-generation pulp and paper mills. The present study focused on comparing the combined cycle with the integration of advanced gas turbines such as steam injected gas turbine (STIG) and evaporative gas turbine (EvGT) in pulp and paper mills. Two categories of simulations have been performed: (1) comparison of gasification of both black liquor and biomass connected to either a combined cycle or steam injected gas turbine with a heat recovery steam generator; (2) externally fired gas turbine in combination with the traditional recovery boiler. The energy demand of the pulp and paper mills is satisfied in all cases and the possibility to deliver a power surplus for external use is verified. The study investigates new system combinations of applications for advanced gas turbines.
7
Kosowski, Krzysztof, Karol Tucki, Marian Piwowarski, Robert Stępień, Olga Orynycz, Wojciech Włodarski e Anna Bączyk. "Thermodynamic Cycle Concepts for High-Efficiency Power Plans. Part A: Public Power Plants 60+". Sustainability 11, n. 2 (21 gennaio 2019): 554. http://dx.doi.org/10.3390/su11020554.
Testo completoAbstract (sommario):
An analysis was carried out for different thermodynamic cycles of power plants with air turbines. Variants with regeneration and different cogeneration systems were considered. In the paper, we propose a new modification of a gas turbine cycle with the combustion chamber at the turbine outlet. A special air by-pass system of the combustor was applied and, in this way, the efficiency of the turbine cycle was increased by a few points. The proposed cycle equipped with a regenerator can provide higher efficiency than a classical gas turbine cycle with a regenerator. The best arrangements of combined air–steam cycles achieved very high values for overall cycle efficiency—that is, higher than 60%. An increase in efficiency to such degree would decrease fuel consumption, contribute to the mitigation of carbon dioxide emissions, and strengthen the sustainability of the region served by the power plant. This increase in efficiency might also contribute to the economic resilience of the area.
8
Bontempo, R., e M. Manna. "Efficiency optimisation of advanced gas turbine recuperative-cycles". Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy 234, n. 6 (1 ottobre 2019): 817–35. http://dx.doi.org/10.1177/0957650919875909.
Testo completoAbstract (sommario):
The paper presents a theoretical analysis of three advanced gas turbine recuperative-cycles, that is, the intercooled, the reheat and the intercooled and reheat cycles. The internal irreversibilities, which characterise the compression and expansion processes, are taken into account through the polytropic efficiencies of the compressors and turbines. As customary in simplified analytical approaches, the study is carried out for an uncooled closed-circuit gas turbine without pressure losses in the heat exchangers and using a calorically perfect gas as working fluid. Although the accurate performance prediction of a real-gas turbine is prevented by these simplifying assumptions, this analysis provides a fast and simple approach which can be used to theoretically explain the main features of the three advanced cycles and to compare them highlighting pros and contra. The effect of the heat recuperation is investigated comparing the thermal efficiency of a given cycle type with those of two reference cycles, namely, the non-recuperative version of the analysed cycle and the simple cycle. As a result, the ranges of the intermediate pressure ratios returning a benefit in the thermal efficiency in comparison with the two reference cycles have been obtained for the first time. Finally, for the sole intercooled and reheat recuperative-cycle, a novel analytical expression for the intermediate pressure ratios yielding the maximum thermal efficiency is also given.
9
Stathopoulos, Panagiotis. "Comprehensive Thermodynamic Analysis of the Humphrey Cycle for Gas Turbines with Pressure Gain Combustion". Energies 11, n. 12 (18 dicembre 2018): 3521. http://dx.doi.org/10.3390/en11123521.
Testo completoAbstract (sommario):
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.
10
Motamed, Mohammad Ali, e Lars O. Nord. "Assessment of Organic Rankine Cycle Part-Load Performance as Gas Turbine Bottoming Cycle with Variable Area Nozzle Turbine Technology". Energies 14, n. 23 (26 novembre 2021): 7916. http://dx.doi.org/10.3390/en14237916.
Testo completoAbstract (sommario):
Power cycles on offshore oil and gas installations are expected to operate more at varied load conditions, especially when rapid growth in renewable energies puts them in a load-following operation. Part-load efficiency enhancement is advantageous since heat to power cycles suffer poor efficiency at part loads. The overall purpose of this article is to improve part-load efficiency in offshore combined cycles. Here, the organic Rankine bottoming cycle with a control strategy based on variable geometry turbine technology is studied to boost part-load efficiency. The Variable Area Nozzle turbine is selected to control cycle mass flow rate and pressure ratio independently. The design and performance of the proposed working strategy are assessed by an in-house developed tool. With the suggested solution, the part-load organic Rankine cycle efficiency is kept close to design value outperforming the other control strategies with sliding pressure, partial admission turbine, and throttling valve control operation. The combined cycle efficiency showed a clear improvement compared to the other strategies, resulting in 2.5 kilotons of annual carbon dioxide emission reduction per gas turbine unit. Compactness, autonomous operation, and acceptable technology readiness level for variable area nozzle turbines facilitate their application in offshore oil and gas installations.
11
Marin, George, Dmitrii Mendeleev e Boris Osipov. "Study of the operation of a 110 MW combined-cycle power unit at minimum loads when operating on the wholesale electricity market". E3S Web of Conferences 216 (2020): 01077. http://dx.doi.org/10.1051/e3sconf/202021601077.
Testo completoAbstract (sommario):
Currently, all generating equipment with a capacity of more than 25 MW operates in the wholesale electricity market. The operation of combined cycle gas turbines is complicated by the implementation of daily load schedules. A distinctive feature of the operation of combined-cycle units is the presence of a gas and steam turbine in the cycle. In this paper, the variable operating modes of a combined cycle plant are considered. The minimum effective load of a gas and steam turbine is determined. An example of the real operation of a steam turbine that is included in a combined cycle plant 110 MW power unit at an operating combined heat and power is shown. The optimal minimum load of a combined cycle gas turbine unit has been determined. As a result of the research, the values of high and low pressure steam flow rates, fuel gas consumption, steam and gas turbine power were obtained. Based on the research results, the optimal minimum load of a combined cycle gas turbine unit was found - 40 MW. This load allows the main and auxiliary equipment to work without compromising reliability.
12
Bolland, O., e J. F. Stadaas. "Comparative Evaluation of Combined Cycles and Gas Turbine Systems With Water Injection, Steam Injection, and Recuperation". Journal of Engineering for Gas Turbines and Power 117, n. 1 (1 gennaio 1995): 138–45. http://dx.doi.org/10.1115/1.2812762.
Testo completoAbstract (sommario):
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.
13
Rice, I. G. "Split Stream Boilers for High-Temperature/High-Pressure Topping Steam Turbine Combined Cycles". Journal of Engineering for Gas Turbines and Power 119, n. 2 (1 aprile 1997): 385–94. http://dx.doi.org/10.1115/1.2815586.
Testo completoAbstract (sommario):
Research and development work on high-temperature and high-pressure (up to 1500°F TIT and 4500 psia) topping steam turbines and associated steam generators for steam power plants as well as combined cycle plants is being carried forward by DOE, EPRI, and independent companies. Aeroderivative gas turbines and heavy-duty gas turbines both will require exhaust gas supplementary firing to achieve high throttle temperatures. This paper presents an analysis and examples of a split stream boiler arrangement for high-temperature and high-pressure topping steam turbine combined cycles. A portion of the gas turbine exhaust flow is run in parallel with a conventional heat recovery steam generator (HRSG). This side stream is supplementary fired opposed to the current practice of full exhaust flow firing. Chemical fuel gas recuperation can be incorporated in the side stream as an option. A significant combined cycle efficiency gain of 2 to 4 percentage points can be realized using this split stream approach. Calculations and graphs show how the DOE goal of 60 percent combined cycle efficiency burning natural gas fuel can be exceeded. The boiler concept is equally applicable to the integrated coal gas fuel combined cycle (IGCC).
14
Ferreira, Sandro B., e Pericles Pilidis. "Comparison of Externally Fired and Internal Combustion Gas Turbines Using Biomass Fuel". Journal of Energy Resources Technology 123, n. 4 (15 giugno 2001): 291–96. http://dx.doi.org/10.1115/1.1413468.
Testo completoAbstract (sommario):
There is a difference of opinion regarding the relative merits of gas turbines using biomass fuels. Some engineers believe that the internal combustion gas turbine coupled to a gasifier will give a higher efficiency than the externally fired gas turbine using pretreated biomass that is not gasified. Others believe the opposite. In this paper, a comparison between these schemes is made, within the framework of the Brazilian perspective. The exergetic analysis of four cycles is described. The first cycle is externally fired (EFGT), the second uses gasified biomass as fuel (BIG/GT), each of them with a combined cycle as a variant (EFGT/CC and BIG/GTCC). These four are then compared to the natural gas turbine cycles (NGT and NGT/CC) in order to evaluate the thermodynamic cost of using biomass. The comparison is carried out in terms of thermal efficiency and in terms of exergetic efficiency and exergy destruction in the main components. The present analysis shows that the EFGT is quite promising. When compared to the NGT cycle, the EFGT gas turbine shows poor efficiency, though this parameter practically equals that of the BIG/GT cycle. The use of a bottoming steam cycle changes the figures, and the EFGT/CC—due to its higher exhaust temperature—results in high efficiency compared to the BIG/GTCC. Its lower initial and maintenance cost may be an important attraction.
15
Longston, Lee. "Electrically Charged". Mechanical Engineering 124, n. 06 (1 giugno 2002): 50–52. http://dx.doi.org/10.1115/1.2002-jun-3.
Testo completoAbstract (sommario):
This article focuses on gas turbines that were produced in 2001 spanning a wide range of capacities. As the engineer's most versatile energy converters, gas turbines producing thrust power continued in 2001 to propel most of the world's aircraft, both military and commercial. The largest commercial jet engines today can produce as much as 120,000 pounds thrust, or some 534,000 Newton. More natural gas pipeline capacity will be added to feed the surge in gas-driven electric power plants that have been corning online in the United States and other parts of the world. The gas turbine may come to be used in a new, commercially promising closed-cycle configuration. A South African company has been working on plans to build and test a prototype of a closed-cycle electric power gas turbine, which uses helium gas as the working fluid and a helium-cooled nuclear reactor to provide heat to power the cycle. If the gas turbine-nuclear reactor power plant is successful, the gas turbine may be the key to yet another energy conversion device, as it has been with record-setting numbers of combined-cycle plants installed worldwide.
16
Kim, T. S., e S. T. Ro. "The effect of gas turbine coolant modulation on the part load performance of combined cycle plants. Part 2: Combined cycle plant". Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy 211, n. 6 (1 settembre 1997): 453–59. http://dx.doi.org/10.1243/0957650981537348.
Testo completoAbstract (sommario):
For combined cycle plants that consist of heavy-duty gas turbine and single-pressure heat recovery steam generator, the effect of gas turbine coolant modulation on plant performance is analysed. Two distinct schemes for gas turbine load control are adopted (the fuel-only control and the variable compressor geometry control), based on the gas turbine calculation in Part 1 of this series of papers. Models for heat recovery steam generator and steam turbine are combined with the gas turbine models of Part 1 to result in a complete analysis routine for combined cycles. The purpose of gas turbine coolant modulation is to minimize coolant consumption by maintaining the turbine blade temperatures as high as possible. It is found that the coolant modulation leads to reduction in heat recovery capacity, which decreases steam cycle power. However, since the benefit of coolant modulation for the gas turbine cycle is large enough, the combine cycle efficiency is improved.
17
Fujii, S., K. Kaneko, K. Otani e Y. Tsujikawa. "Mirror Gas Turbines: A Newly Proposed Method of Exhaust Heat Recovery". Journal of Engineering for Gas Turbines and Power 123, n. 3 (1 ottobre 2000): 481–86. http://dx.doi.org/10.1115/1.1366324.
Testo completoAbstract (sommario):
A new conceptual combination of Brayton and inverted Brayton cycles with a heat sink by intercooling, which is dubbed the mirror gas turbine, has been evaluated and proposed in this paper. Prior to such evaluations, a preliminary test on the inverted cycle without intercooling was made experimentally to confirm the actual operation. The conventional method of recuperation in gas turbines can be replaced by the mirror gas turbine with a low working temperature of about 450°C at heat exchanger. The combined cycle of Brayton/Rankine for electricity generation plant may be improved by our concept into a system with steam turbines completely removed and with still high thermal efficiency. Ultra-micro turbines will be possible, producing the output power less than 10 kW as well as thermal efficiency of 20 percent.
18
Langston, Lee S. "Is there a Supercharged Gas Turbine in your Future?" Mechanical Engineering 137, n. 05 (1 maggio 2015): 58–59. http://dx.doi.org/10.1115/1.2015-may-5.
Testo completoAbstract (sommario):
This article discusses various features of supercharged gas turbine and supercharged analysis. One 400 MW supercharged gas turbine power plant variant analysed by Wettstein yielded a predicted thermal efficiency of 60 percent, rivaling current combined cycle values. The supercharged gas turbine power plant proposed by Wettstein is a semi-closed (SC) cycle. The SC cycle is an amalgamation of closed and open cycles. It consists of a gas turbine having an internal combustor for energy input to the cycle. With a SC cycle, a designer now has some of the best features of both open and closed to move SC power plant operation in different directions. With internal combustion, the SC cycle is not constrained by the temperature limitations of the closed cycle. The supercharged gas turbine power plant looks very promising. In another ASME paper, Wettstein shows how gas turbine supercharging could benefit marine propulsion.
19
Zhang, Xiaotao, Yichao Wu, Wenxian Zhang, Qixian Wang e Aijun Wang. "System Performance and Pollutant Emissions of Micro Gas Turbine Combined Cycle in Variable Fuel Type Cases". Energies 15, n. 23 (1 dicembre 2022): 9113. http://dx.doi.org/10.3390/en15239113.
Testo completoAbstract (sommario):
This study focuses on an investigation of the operating performance and pollutant emission characteristics of a micro gas turbine combined cycle using biomass gas, replacing natural gas. The models of both recuperative cycle micro gas turbines with a waste heat utilization system and a micro gas-steam turbine combined cycle system are established. When the gas turbine works at 100 kW and the same types of fuel are burnt, the recuperative cycle system consumes less fuel than the gas-steam combined cycle system. The electric efficiency of the recuperative cycle system can reach more than 29%, which is higher than 24% of the gas-steam combined system. The combined cycle thermal efficiency of the recuperative system is as high as 66%, with 36% waste heat utilization efficiency. The electrical efficiency of the recuperative cycle system in the biomass gas case decreases, while that of the gas-steam combined cycle system undergoes little change. When the gas turbine power output increases from 50 kW to 100 kW, the electrical efficiency and combined cycle thermal efficiency increases, but the thermal efficiency of waste heat utilization of recuperative cycle decreases, the NOX and SO2 emissions gradually rise. Under the same working conditions, the NOX emissions of the recuperative cycle system are greater than that of the steam-gas combined cycle system.
20
Qi, Lei, Zhitao Wang, Ningbo Zhao, Yongqiang Dai, Hongtao Zheng e Qingyang Meng. "Investigation of the Pressure Gain Characteristics and Cycle Performance in Gas Turbines Based on Interstage Bleeding Rotating Detonation Combustion". Entropy 21, n. 3 (8 marzo 2019): 265. http://dx.doi.org/10.3390/e21030265.
Testo completoAbstract (sommario):
To further improve the cycle performance of gas turbines, a gas turbine cycle model based on interstage bleeding rotating detonation combustion was established using methane as fuel. Combined with a series of two-dimensional numerical simulations of a rotating detonation combustor (RDC) and calculations of cycle parameters, the pressure gain characteristics and cycle performance were investigated at different compressor pressure ratios in the study. The results showed that pressure gain characteristic of interstage bleeding RDC contributed to an obvious performance improvement in the rotating detonation gas turbine cycle compared with the conventional gas turbine cycle. The decrease of compressor pressure ratio had a positive influence on the performance improvement in the rotating detonation gas turbine cycle. With the decrease of compressor pressure ratio, the pressurization ratio of the RDC increased and finally made the power generation and cycle efficiency enhancement rates display uptrends. Under the calculated conditions, the pressurization ratios of RDC were all higher than 1.77, the decreases of turbine inlet total temperature were all more than 19 K, the power generation enhancements were all beyond 400 kW and the cycle efficiency enhancement rates were all greater than 6.72%.
21
Moore, M. J. "Nox emission control in gas turbines for combined cycle gas turbine plant". Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy 211, n. 1 (1 febbraio 1997): 43–52. http://dx.doi.org/10.1243/0957650971536980.
Testo completoAbstract (sommario):
The increase, in recent years, in the size and efficiency of gas turbines burning natural gas in combined cycle has occurred against a background of tightening environmental legislation on the emission of nitrogen oxides. The higher turbine entry temperatures required for efficiency improvement tend to increase NOx production. First-generation emission control systems involved water injection and catalytic reduction and were relatively expensive to operate. Dry low-NOx combustion systems have therefore been developed but demand more primary air for combustion. This gives added incentive to the reduction of air requirements for cooling the combustor and turbine blading. This paper reviews the various approaches adopted by the main gas turbine manufacturers which are achieving very low levels of NOx emission from natural gas combustion. Further developments, however, are necessary for liquid fuels.
22
Langston, Lee S. "Gas Turbines and Natural Gas Synergism". Mechanical Engineering 135, n. 02 (1 febbraio 2013): 30–35. http://dx.doi.org/10.1115/1.2013-feb-4.
Testo completoAbstract (sommario):
This article presents a study on new electric power gas turbines and the advent of shale natural gas, which now are upending electrical energy markets. Energy Information Administration (EIA) results show that total electrical production cost for a conventional coal plant would be 9.8 cents/kWh, while a conventional natural gas fueled gas turbine combined cycle plant would be a much lower at 6.6 cents/kWh. Furthermore, EIA estimates that 70% of new US power plants will be fueled by natural gas. Gas turbines are the prime movers for the modern combined cycle power plant. On the natural gas side of the recently upended electrical energy markets, new shale gas production and the continued development of worldwide liquefied natural gas (LNG) facilities provide the other element of synergism. The US natural gas prices are now low enough to compete directly with coal. The study concludes that the natural gas fueled gas turbine will continue to be a growing part of the world’s electric power generation.
23
Bhargava, R., M. Bianchi, A. Peretto e P. R. Spina. "A Feasibility Study of Existing Gas Turbines for Recuperated, Intercooled, and Reheat Cycle". Journal of Engineering for Gas Turbines and Power 126, n. 3 (1 luglio 2004): 531–44. http://dx.doi.org/10.1115/1.1707033.
Testo completoAbstract (sommario):
In the present paper, a comprehensive and simple in application design methodology to obtain a gas turbine working on recuperated, intercooled, and reheat cycle utilizing existing gas turbines is presented. Applications of the proposed design steps have been implemented on the three existing gas turbines with wide ranging design complexities. The results of evaluated aerothermodynamic performance for these existing gas turbines with the proposed modifications are presented and compared in this paper. Sample calculations of the analysis procedures discussed, including stage-by-stage analysis of the compressor and turbine sections of the modified gas turbines, have been also included. All the three modified gas turbines were found to have higher performance, with cycle efficiency increase of 9% to 26%, in comparison to their original values.
24
Horlock, J. H. "The Evaporative Gas Turbine [EGT] Cycle". Journal of Engineering for Gas Turbines and Power 120, n. 2 (1 aprile 1998): 336–43. http://dx.doi.org/10.1115/1.2818127.
Testo completoAbstract (sommario):
Humidification of the flow through a gas turbine has been proposed in a variety of forms. The STIG plant involves the generation of steam by the gas turbine exhaust in a heat recovery steam generator (HRSG), and its injection into or downstream of the combustion chamber. This increases the mass flow through the turbine and the power output from the plant, with a small increase in efficiency. In the evaporative gas turbine (or EGT) cycle, water is injected in the compressor discharge in a regenerative gas turbine cycle (a so-called CBTX plant—compressor [C], burner [B], turbine [T], heat exchanger [X]); the air is evaporatively cooled before it enters the heat exchanger. While the addition of water increases the turbine mass flow and power output, there is also apparent benefit in reducing the temperature drop in the exhaust stack. In one variation of the basic EGT cycle, water is also added downstream of the evaporative aftercooler, even continuously in the heat exchanger. There are several other variations on the basic cycle (e.g., the cascaded humidified advanced turbine [CHAT]). The present paper analyzes the performance of the EGT cycle. The basic thermodynamics are first discussed, and related to the cycle analysis of a dry regenerative gas turbine plant. Subsequently some detailed calculations of EGT cycles are presented. The main purpose of the work is to seek the optimum pressure ration in the EGT cycle for given constraints (e.g., fixed maximum to minimum temperature). It is argued that this optimum has a relatively low value.
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E. H. Betelmal, A. M. Naas e A. Mjani. "Energy and exergy analysis of a simple gas turbine combined with linde cycle and N2 injected into the compressor of the gas turbine". GSC Advanced Engineering and Technology 1, n. 1 (30 maggio 2021): 006–15. http://dx.doi.org/10.30574/gscaet.2021.1.1.0001.
Testo completoAbstract (sommario):
In this paper, we investigated a thermodynamic model of the regeneration gas turbine cycle with nitrogen supplied during the compression process. A suitable quantity of nitrogen that comes from the air separation cycle (Linde cycle) is injected between the stages of the compressor where it is evaporated, then the nitrogen and air mixture enters into the combustion chamber where it is burned and expanded in the turbine. We used this method to reduce greenhouse gases and improve gas turbine efficiency. In this work, we evaluated the operational data of the regeneration gas turbine cycle and the maximum amount of nitrogen that can be injected into the compressor. We also investigated the performance variation due to nitrogen spray into the compressor, and the effect of varying ambient temperature on the performance of gas turbines (thermal efficiency, power), as well as a comparison between the normal gas turbine cycle, and the remodelled compression cycle. The exergy analysis shows that the injection of the nitrogen will increase exergy destruction. The results demonstrated an 8% increase in the efficiency of the cycle, furthermore, CO2 emission decreased by 11% when the nitrogen was injected into the compressor.
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Bulanin, V. A. "USE OF GAS TURBINES FOR COMBINED ENERGY PRODUCTION". Herald of Dagestan State Technical University. Technical Sciences 47, n. 1 (21 aprile 2020): 8–18. http://dx.doi.org/10.21822/2073-6185-2020-47-1-8-18.
Testo completoAbstract (sommario):
Abstract. Aim. Despite the obvious expediency of their widespread implementation, gas turbine (GT) and combined cycle gas turbine (CCGT) plants were only used in limited quantities in the former USSR and CIS countries. Due to the exhaustion of possibilities to increase the fuel use efficiency and return on investment (ROI) in steam-turbine combined heat and power (CHP) plants, the development of GT and CCGT plants becomes an urgent problem. In current global practice, the primary fuel for gas turbines and combined cycle gas turbines is natural gas. However, until recently, there has been a lack of experience in the design, construction and operation of GT and CCGT plants in the CIS countries. Method. Due to the ad hoc nature of research in this area, it was necessary to systematise the results of existing studies and assess the state of research at the world level taking regional characteristics into account. Results. The article presents the main considerations and potential effectiveness of the use of gas turbines. Basic gas turbine construction schemes are investigated along with their techno-economic characteristics and an assessment of their comparative utility. Conclusion. Considering the widespread availability of natural gas, it is recommended that gas turbine and combined-cycle plants be installed as part of the process of technical re-equipment in the fuel and energy complex, industry, agriculture and municipal energy sectors as part of the design and construction of new energy sources in the light of positive world experience and the current level of development of gas turbine technologies. Ubiquitous implementation of gas turbine units in the centres supplying heat and electric loads will reduce the regional economy’s need for energy fuel and ensure an increase in energy capacity without the need to construct new complex and uneconomic steam turbine power plants.
27
Zwebek, A. I., e P. Pilidis. "Degradation Effects on Combined Cycle Power Plant Performance—Part III: Gas and Steam Turbine Component Degradation Effects". Journal of Engineering for Gas Turbines and Power 126, n. 2 (1 aprile 2004): 306–15. http://dx.doi.org/10.1115/1.1639007.
Testo completoAbstract (sommario):
This paper presents an investigation of the degradation effects that gas and steam turbine cycles components have on combined cycle (CCGT) power plant performance. Gas turbine component degradation effects were assessed with TurboMatch, the Cranfield Gas Turbine simulation code. A new code was developed to assess bottoming cycle performance deterioration. The two codes were then joined to simulate the combined cycle performance deterioration as a whole unit. Areas examined were gas turbine compressor and turbine degradation, HRSG degradation, steam turbine degradation, condenser degradation, and increased gas turbine back pressure due to HRSG degradation. The procedure, assumptions made, and the results obtained are presented and discussed. The parameters that appear to have the greatest influence on degradation are the effects on the gas generator.
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Marin Begović. "MAINTAINING DECLARED PERFORMANCE IN GAS TURBINES DURING INCREASED AMBIENT TEMPERATURES". Journal of Energy - Energija 58, n. 2 (16 settembre 2022): 192–207. http://dx.doi.org/10.37798/2009582298.
Testo completoAbstract (sommario):
The classical gas turbine process is characterised by air compression from its surroundings, heating fuel in the combustion chambers, hence causing the created flue gases to expand in the turbine and thus induce mechanical action. The performance of gas turbine depends on anything that affects the airflow density and/or mass at the compressor inlet. The most obvious changes in gas turbine performance is a reduction in power and an increase in specific fuel consumption following an increase in the ambient temperature, resulting in significant deviations of the guaranteed (and achieved) values at ISO conditions. In cooling air at the compressor inlet at increased ambient temperatures, an increase in the mass flow and compression ratio is achieved, thus preventing a reduction in power and an increase in specific fuel consumption. When using gas turbines in combined cycle cogeneration power plants for the production of electrical and thermal power, increasing mass flow through gas turbines leads to an increase in power transferred by the flue gases to the turbine exhaust, and which in the waste heat recovery boiler at the combined cycle plant transfers to the steam turbine cycle. Consequently, the effect at the combined cycle plant is a more significant reduction in specific fuel consumption. The work has used the example of the GE-PG610FA turbine to show the dependency on surrounding climatic conditions, and the manner in which this dependency can be reduced or removed.
29
Piwowarski, Marian, Krzysztof Kosowski e Marcin Richert. "Organic Supercritical Thermodynamic Cycles with Isothermal Turbine". Energies 16, n. 12 (15 giugno 2023): 4745. http://dx.doi.org/10.3390/en16124745.
Testo completoAbstract (sommario):
Organic Rankine cycles (ORC) are quite popular, but the overall efficiencies of these plants are rather very low. Numerous studies have been conducted in many scientific centers and research centers to improve the efficiency of such cycles. The research concerns both the modification of the cycle and the increase in the parameters of the medium at the inlet to the turbine. However, the efficiency of even these modified cycles rarely exceeds 20%. The plant modifications and the optimization of the working medium parameters, as a rule, lead to cycles with the high pressure and high temperature of live vapor and with a regenerator (heat exchanger) for the heating, vaporization and superheating of the medium. A new modified cycle with supercritical parameters of the working medium and with a new type of turbine has been described and calculated in the paper. For the first time, the isothermal turbine is proposed for supercritical organic cycles, though this solution is known as the Ericsson cycle for gas turbines. The innovative cycle and the usual ORC plants are characterized by almost identical block diagrams, while in the proposed cycle, the work of the turbine is obtained as a result of isothermal expansion and not in an adiabatic process. The analysis has been performed for 11 different working media and two cycles. The calculations have shown that power plants with isothermal expansion achieve better efficiency than cycles with adiabatic turbines. For example, the rise in efficiency changes from 8 percentage points for R245fa up to 10 percentage points for acetone. The calculations have proved that it is possible to obtain efficiency exceeding 50% for organic power plants. This is an outstanding result compared with modern steam and gas turbine units.
30
Carcasci, C., B. Facchini e S. Harvey. "Design issues and performance of a chemically recuperated aeroderivative gas turbine". Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy 212, n. 5 (1 agosto 1998): 315–29. http://dx.doi.org/10.1243/0957650981536899.
Testo completoAbstract (sommario):
A number of innovative gas turbine cycles have been proposed lately, including the humid air turbine (HAT) and the chemically recuperated gas turbine (CRGT). The potential of the CRGT cycle lies in the ability to generate power with a high efficiency and ultra-low NOx emissions. Much of the research work published on the CRGT cycle is restricted to an analysis of the thermodynamic potential of the cycle. However, little work has been devoted to discussion of some of the relevant design and operation issues of such cycles. In this paper, part-load performance characteristics are presented for a CRGT cycle based on an aeroderivative gas turbine engine adapted for chemical recuperation. The paper also includes discussion of some of the design issues for the methane-steam reformer component of the cycle. The results of this study show that large heat exchange surface areas and catalyst volumes are necessary to ensure sufficient methane conversion in the methane steam reformer section of the cycle. The paper also shows that a chemically recuperated aeroderivative gas turbine has similar part-load performance characteristics compared with the corresponding steam-injected gas turbine (STIG) cycle.
31
Zwebek, A., e P. Pilidis. "Degradation Effects on Combined Cycle Power Plant Performance—Part I: Gas Turbine Cycle Component Degradation Effects". Journal of Engineering for Gas Turbines and Power 125, n. 3 (1 luglio 2003): 651–57. http://dx.doi.org/10.1115/1.1519271.
Testo completoAbstract (sommario):
This paper describes the effects of degradation of the main gas path components of the gas turbine topping cycle on the combined cycle gas turbine (CCGT) plant performance. First, the component degradation effects on the gas turbine performance as an independent unit are examined. It is then shown how this degradation is reflected on a steam turbine plant of the CCGT and on the complete combined cycle plant. TURBOMATCH, the gas turbine performance code of Cranfield University, was used to predict the effects of degraded gas path components of the gas turbine have on its performance as a whole plant. To simulate the steam (bottoming) cycle, another Fortran code was developed. Both codes were used together to form a complete software system that can predict the CCGT plant design point, off-design, and deteriorated (due to component degradation) performances. The results show that the overall output is very sensitive to many types of degradation, especially in the turbine of the gas turbine. Also shown is the effect on gas turbine exhaust conditions and how this affects the steam cycle.
32
Li, Jiangpeng, Ziti Liu e Ruoxuan Ye. "Current Status and Prospects of Gas Turbine Technology Application". Journal of Physics: Conference Series 2108, n. 1 (1 novembre 2021): 012009. http://dx.doi.org/10.1088/1742-6596/2108/1/012009.
Testo completoAbstract (sommario):
Abstract The gas turbine is widely used in various fields, including powering aircraft, ships, trains, and electrical generators. This paper reviews multiple researches about two usages of gas turbines, including power generation and propulsion in aerospace. To be specific, two types of gas turbines have been considered in the power generation section. The first one is the micro-scale turbine, and its working principle has been introduced in section 2.1.1. In addition, six diverse kinds of gas turbines, sorted by a different manufacturer, are introduced in 2.1.2, and it has been found out that, compared to its counterpart, EnerTwin is obviously more sustainable. At the same time, both of them generally cost the same. The second type of gas turbine is used in a combined cycle power plant (CCPP), a popular power station. The working principle of CCPP is introduced in 2.2.1, while several optimization methods are illustrated in 2.2.2, including solar thermal power methods and other novel methods. The result indicates that the most popular method of optimizing the combined cycle gas turbine is integrating an additional unit. One of those outstanding technics is the integrated solar-combined cycle, contributing to 64% of fuel saving with 2.8% of output reduction.
33
Langston, Lee S. "Air Race". Mechanical Engineering 132, n. 05 (1 maggio 2010): 34–38. http://dx.doi.org/10.1115/1.2010-may-3.
Testo completoAbstract (sommario):
This article presents an overview of the existence and use of gas turbines in the past, present, and future. The article uses the data provided by Forecast International of Newtown, Conn., which covers both aviation and nonaviation gas turbine markets. The gas turbine has proven to be an example of technological evolution, where improvements in efficiency and reliability continue to amass, 70 years after its invention. Advanced technology developed in military jet engines has often migrated to commercial jet engines and nonaviation gas turbines, and improved their performance. Gas turbine combined-cycle power plants come in all sizes. The largest combined-cycle gas turbines are the H class machines made by GE and Siemens. Given the world’s current focus on sustainable or renewable energy, how do natural gas-fired gas turbines fit in? In some instances, renewable energy, such as solar or wind, just would not be practical without assistance from gas turbines. As power production moves tentatively into a low-carbon future, or as people look for more fuel-efficient ways to cross continents, it’s a sure bet that gas turbines will be there.
34
Harvey, S. P., K. F. Knoche e H. J. Richter. "Reduction of Combustion Irreversibility in a Gas Turbine Power Plant Through Off-Gas Recycling". Journal of Engineering for Gas Turbines and Power 117, n. 1 (1 gennaio 1995): 24–30. http://dx.doi.org/10.1115/1.2812776.
Testo completoAbstract (sommario):
Combustion in conventional fossil-fueled power plants is highly irreversible, resulting in poor overall energy conversion efficiency values (less than 40 percent in many cases). The objective of this paper is to discuss means by which this combustion irreversibility might be reduced in gas turbine power cycles, and the conversion efficiency thus improved upon. One such means is thermochemical recuperation of exhaust heat. The proposed cycle recycles part of the exhaust gases, then mixes them with fuel prior to injection into a reformer. The heat required for the endothermic reforming reactions is provided by the hot turbine exhaust gases. Assuming state-of-the-art technology, and making a number of simplifying assumptions, an overall efficiency of 65.4 percent was attained for the cycle, based on the lower heating value (LHV) of the methane fuel. The proposed cycle is compared to a Humid Air Turbine (HAT) cycle with similar features that achieves an overall efficiency of 64.0 percent. The gain in cycle efficiency that can be attributed to the improved fuel oxidation process is 1.4 percentage points. Compared to current high-efficiency gas turbine cycles, the high efficiency of both cycles studied therefore results mainly from the use of staged compression and expansion with intermediate cooling and reheating, respectively.
35
Langston, Lee S. "Fahrenheit 3,600". Mechanical Engineering 129, n. 04 (1 aprile 2007): 34–37. http://dx.doi.org/10.1115/1.2007-apr-3.
Testo completoAbstract (sommario):
This article illustrates capabilities of gas turbines to be able to work in extremely elevated temperatures. The turbine airfoils in the new F135 jet engine that powers the Joint Strike Fighter (JSF) Lightning II are capable of operating at these extreme temperatures. The F135 gas turbine is the first production jet engine in this new 3,600°F class, designed to withstand these highest, record-breaking turbine inlet temperatures. The JSF engine is just one product in the $3.7 billion military gas turbine market, which includes jet engine production for the world’s fighter aircraft military cargo, transport, refuelling, and special-purpose aircraft. The article also discusses the features of H Class, which is the largest electric power gas turbine that has been interpreted as an abbreviation for humongous. Non-aviation gas turbines consist of electrical power generation, mechanical drive, and marine. The largest segment of that market by far is electrical power generation, in simple cycle, combined cycle, and cogeneration. Forecast International predicts significant growth in coming years in demand for gas turbine electrical power generation, rising from $8.6 billion in 2006 to a projected $13.5 billion in 2008, a 60 percent increase.
36
Jansen, M., T. Schulenberg e D. Waldinger. "Shop Test Result of the V64.3 Gas Turbine". Journal of Engineering for Gas Turbines and Power 114, n. 4 (1 ottobre 1992): 676–81. http://dx.doi.org/10.1115/1.2906641.
Testo completoAbstract (sommario):
The V64.3 60-MW combustion turbine is the first of a new generation of high-temperature gas turbines, designed for 50 and 60 Hz simple cycle, combined cycle, and cogeneration applications. The prototype engine was tested in 1990 in the Berlin factories under the full range of operation conditions. It was equipped with various measurement systems to monitor pressures, gas and metal temperatures, clearances, strains, vibrations, and exhaust emissions. The paper describes the engine design, the test facility and instrumentation, and the engine performance. Results are given for turbine blade temperatures, compressor and turbine vibrations, exhaust gas temperature, and NOx emissions for combustion of natural gas and fuel oil.
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Lunghi, P., e S. Ubertini. "Efficiency Upgrading of an Ambient Pressure Molten Carbonate Fuel Cell Plant Through the Introduction of an Indirect Heated Gas Turbine". Journal of Engineering for Gas Turbines and Power 124, n. 4 (24 settembre 2002): 858–66. http://dx.doi.org/10.1115/1.1492839.
Testo completoAbstract (sommario):
The efficient end environmentally friendly production of electricity is undoubtedly one of the 21st century priorities. Since renewable sources will be able to guarantee only a share of the future demand, the present research activity must focus on innovative energy devices and improved conversion systems and cycles. Great expectations are reserved to fuel cell systems. The direct conversion from chemical to electrical energy eliminates environmental problems connected with combustion and bypass the stringent efficiency limit due to Carnot’s principle. Still in infancy, high-temperature fuel cells present the further advantage of feasible cycle integration with steam or gas turbines. In this paper, a molten carbonate fuel cell plant is simulated in a cycle for power generation. The introduction of an external combustion gas turbine is evaluated with the aim of efficiency and net power output increase. The results show that the proposed cycle can be conveniently used as a source of power generation. As compared to internal combustion gas turbine hybrid cycles found in the literature the plant is characterized by fuel cell greater simplicity, due to the absence of pressurization, and gas turbine increased complexity, due to the presence of the heat exchange system.
38
Wiggins, J. O. "The “Axi-Fuge”—A Novel Compressor". Journal of Turbomachinery 108, n. 2 (1 ottobre 1986): 240–43. http://dx.doi.org/10.1115/1.3262043.
Testo completoAbstract (sommario):
Modifying a simple-cycle gas turbine to include heat exchangers can improve its thermal efficiency significantly (as much as 20 percent). Advanced regenerative and intercooled regenerative gas turbines for marine application have recently been the subject of numerous studies, most of which have shown that lower fuel consumption can be achieved by adding heat exchangers to existing simple-cycle gas turbines. Additional improvements in thermal efficiency are available by increasing the efficiency of the turbomachinery itself, particularly that of the gas turbine’s air compressor. Studies by Caterpillar Tractor Company and Solar Turbines Incorporated on a recuperated, variable-geometry gas turbine indicate an additional 8 to 10 percent improvement in thermal efficiency is possible when an improved higher efficiency compressor is included in the gas turbine modification. During these studies a novel compressor, the Axi-Fuge, was devised. This paper discusses the Axi-Fuge concept, its origin, design criteria and approach, and some test results.
39
Langston, Lee S. "Forward Future". Mechanical Engineering 137, n. 06 (1 giugno 2015): 32–37. http://dx.doi.org/10.1115/1.2015-jun-1.
Testo completoAbstract (sommario):
This study analyses the changes that gas turbines have brought in the field of air and land transport and technology. The worldwide production of gas turbines includes the commercial and military aviation markets, as well as non-aviation markets for electrical generation, marine applications, and mechanical power. In recent years, gas turbine combined-cycle plants have become key players in the generation of electric power. Aviation gas turbines make up the largest segment, whereas, the non-aviation gas turbine market is characterized by a particular vitality and volatility. The original equipment manufacturers (OEM) who supply large gas turbine combined-cycle plants are General Electric (GE), Siemens, Mitsubishi, and Alstom. And soon, the industry will be consolidated further, as GE is in the process of acquiring the power segment of Alstom, thus narrowing the field of large plant OEMs to a big three – similar to the threesome in aviation: GE, Rolls-Royce, and Pratt & Whitney – with GE in the lead.
40
El-Masri, M. A. "On Thermodynamics of Gas-Turbine Cycles: Part 3—Thermodynamic Potential and Limitations of Cooled Reheat-Gas-Turbine Combined Cycles". Journal of Engineering for Gas Turbines and Power 108, n. 1 (1 gennaio 1986): 160–68. http://dx.doi.org/10.1115/1.3239864.
Testo completoAbstract (sommario):
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.
41
Bhargava, R., M. Bianchi, G. Negri di Montenegro e A. Peretto. "Thermo-Economic Analysis of an Intercooled, Reheat and Recuperated Gas Turbine for Cogeneration Applications–Part I: Base Load Operation". Journal of Engineering for Gas Turbines and Power 124, n. 1 (1 febbraio 2000): 147–54. http://dx.doi.org/10.1115/1.1413463.
Testo completoAbstract (sommario):
This paper presents a thermo-economic analysis of an intercooled, reheat (ICRH) gas turbine, with and without recuperation, for cogeneration applications. The optimization analyses of thermodynamic parameters have permitted to calculate variables, such as low-pressure compressor pressure ratio, high-pressure turbine pressure ratio and gas temperature at the waste heat recovery unit inlet while maximizing electric efficiency and “Energy Saving Index.” Subsequently, the economic analyses have allowed to evaluate return on the investment, and the minimum value of gross payout period, for the cycle configurations of highest thermodynamic performance. In the present study three sizes (100 MW, 20 MW, and 5 MW) of gas turbines have been examined. The performed investigation reveals that the maximum value of electric efficiency and “Energy Saving Index” is achieved for a large size (100 MW) recuperated ICRH gas turbine based cogeneration system. However, a nonrecuperated ICRH gas turbine (of 100 MW) based cogeneration system provides maximum value of return on the investment and the minimum value of gross payout period compared to the other gas turbine cycles, of the same size and with same power to heat ratio, investigated in the present study. A comprehensive thermo-economic analysis methodology, presented in this paper, should provide useful guidelines for preliminary sizing and selection of gas turbine cycle for cogeneration applications.
42
Marin, G. E., B. M. Osipov e D. I. Mendeleev. "Research on the influence of fuel gas on energy characteristics of a gas turbine". E3S Web of Conferences 124 (2019): 05063. http://dx.doi.org/10.1051/e3sconf/201912405063.
Testo completoAbstract (sommario):
The purpose of this paper is to study and analyze the gas turbine engine and the thermodynamic cycle of a gas turbine. The article describes the processes of influence of the working fluid composition on the parameters of the main energy gas turbines, depending on the composition of the fuel gas. The calculations of the thermal scheme of a gas turbine, which were made using mathematical modeling, are given. As a result of research on the operation of the GE PG1111 6FA gas turbine installation with various gas compositions, it was established that when the gas turbine is operating on different fuel gases, the engine efficiency changes. The gas turbine efficiency indicators were determined for various operating parameters and fuel composition. The impact of fuel components on the equipment operation is revealed.
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Eflita Yohana, Tony Suryo Utomo, Muhammad Ichwan Faried, Mohammad Farkhan Hekmatyar Dwinanda e Mohamad Endy Yulianto. "Exergy and Energy Analysis of Gas Turbine Generator X Combined Cycle Power Plant Using Cycle-Tempo Software". Journal of Advanced Research in Fluid Mechanics and Thermal Sciences 104, n. 1 (3 aprile 2023): 37–46. http://dx.doi.org/10.37934/arfmts.104.1.3746.
Testo completoAbstract (sommario):
Increasing electricity production must continue to be pursued to meet the increasing electricity needs of the community. One of the efforts that engineers can make is to improve the performance of the main suppliers of electricity needs. It is impossible to separate the role of the system's components from the performance of the gas turbine generator. This journal discusses exergy and energy analysis in the gas turbine generator of X combined cycle power plant through simulation with Cycle-Tempo software. The simulation results show that the highest system energy efficiency is owned by the gas turbine generator unit 2.3 of 35.541%, with a system exergy efficiency of 34.069%. The lowest system energy efficiency is owned by the gas turbine generator unit 2.1 of 31.669%, with a system exergy efficiency of 30.355%. The gas turbine generator component with the lowest exergy efficiency occurs in the combustion chamber of the gas turbine generator unit 2.2 of 76.81%, with exergy destruction of 92.581 MW. Meanwhile, the gas turbine generator component with the highest exergy efficiency occurred in the turbine of the gas turbine generator unit 2.3 of 96.81%, with exergy destruction of 9.762 MW. The simulation results that have been carried out show that the performance of the components in the gas turbine generator is still in good performance, with the lowest exergy efficiency above 75%.
44
Smith, A. R., J. Klosek e D. W. Woodward. "Next-Generation Integration Concepts for Air Separation Units and Gas Turbines". Journal of Engineering for Gas Turbines and Power 119, n. 2 (1 aprile 1997): 298–304. http://dx.doi.org/10.1115/1.2815575.
Testo completoAbstract (sommario):
The commercialization of Integrated Gasification Combined Cycle (IGCC) Power has been aided by concepts involving the integration of a cryogenic air separation unit (ASU) with the gas turbine combined-cycle module. Other processes, such as coal-based ironmaking and combined power/industrial gas production facilities, can also benefit from the integration. It is known and now widely accepted that an ASU designed for “elevated pressure” service and optimally integrated with the gas turbine can increase overall IGCC power output, increase overall efficiency, and decrease the net cost of power generation when compared to nonintegrated facilities employing low-pressure ASUs. The specific gas turbine, gasification technology, NOx emission specification, and other site specific factors determine the optimal degree of compressed air and nitrogen stream integration. Continuing advancements in both air separation and gas turbine technologies offer new integration opportunities to improve performance and reduce costs. This paper reviews basic integration principles and describes next-generation concepts based on advanced high pressure ratio gas turbines, Humid Air Turbine (HAT) cycles and integration of compression heat and refrigeration sources from the ASU. Operability issues associated with integration are reviewed and control measures are described for the safe, efficient, and reliable operation of these facilities.
45
Bianchi, M., G. Negri di Montenegro, A. Peretto e P. R. Spina. "A Feasibility Study of Inverted Brayton Cycle for Gas Turbine Repowering". Journal of Engineering for Gas Turbines and Power 127, n. 3 (24 giugno 2005): 599–605. http://dx.doi.org/10.1115/1.1765121.
Testo completoAbstract (sommario):
In the paper a feasibility study of inverted Brayton cycle (IBC) engines, for the repowering of existing gas turbines, is presented. The following main phases have been carried out: (i) identification of the more suitable gas turbines to be repowered by means of an IBC engine; (ii) designing of the IBC components. Once the IBC engines for the candidate gas turbines were designed, an analysis has been developed to check the possibility to match these engines with other gas turbines, similar to those for which the IBC engines have been designed. In all the analyzed cases the evaluated performance result only slightly worse than that obtainable by repowering the same gas turbine with IBC engines ad hoc designed.
46
Kumar, P. V. Ram, e R. S. Misra. "Thermodynamic Analysis on Steam Injected Gas Turbine cycle". International Journal of Advance Research and Innovation 5, n. 2 (2017): 213–18. http://dx.doi.org/10.51976/ijari.521735.
Testo completoAbstract (sommario):
This paper presents thermodynamic methodology for the performance evaluation of steam injected gas turbine(STIG) cycle. The effects of pressure ratio, turbine inlet temperature and specific mass flow rate of steam per kg of air used in the thermodynamic analysis of steam injected gas turbine(STIG) cycle on thermal efficiency of the cycle, specific work output and specific fuel consumption have been investigated. From the results obtained in graphs it is observed that thermal efficiency of steam injected gas turbine(STIG) cycle increases and net work output increases and specific fuel consumption decreases as pressure ratio increases; thermal efficiency of steam injected gas turbine(STIG) cycle and specific work output increases with increase in turbine inlet temperature. Results also show that STIG cycle efficiency is always greater than simple gas turbine cycle for same pressure ratio and turbine inlet temperature and for wide range of parameters STIG cycle is superior to simple gas turbine cycle. In STIG cycle as specific mass flow rate per kg of air increases cycle efficiency and net work output also increases.
47
Bazaluk, Oleg, Valerii Havrysh, Oleksandr Cherednichenko e Vitalii Nitsenko. "Chemically Recuperated Gas Turbines for Offshore Platform: Energy and Environmental Performance". Sustainability 13, n. 22 (14 novembre 2021): 12566. http://dx.doi.org/10.3390/su132212566.
Testo completoAbstract (sommario):
Currently, offshore areas have become the hotspot of global gas and oil production. They have significant reserves and production potential. Offshore platforms are energy-intensive facilities. Most of them are equipped with gas turbine engines. Many technologies are used to improve their thermal efficiency. Thermochemical recuperation is investigated in this paper. Much previous research has been restricted to analyzing of the thermodynamic potential of the chemically recuperated gas turbine cycle. However, little work has discussed the operation issues of this cycle. The analysis of actual fuel gases for the steam reforming process taking into account the actual load of gas turbines, the impact of steam reforming on the Wobbe index, and the impact of a steam-fuel reforming process on the carbon dioxide emissions is the novelty of this study. The obtained simulation results showed that gas turbine engine efficiency improved by 8.1 to 9.35% at 100% load, and carbon dioxide emissions decreased by 10% compared to a conventional cycle. A decrease in load leads to a deterioration in the energy and environmental efficiency of chemically recuperated gas turbines.
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MUTO, Yasushi, Shintaro ISHIYAMA, Seiya YAMADA, Iwao MATSUMOTO, Chiharu KAWASE, Yoshitaka FUKUYAMA e Tadaharu KISHIBE. "Conceptual Design of HTGR Direct Cycle Gas Turbine : Gas Turbine Design". Proceedings of the JSME annual meeting 2000.4 (2000): 397–98. http://dx.doi.org/10.1299/jsmemecjo.2000.4.0_397.
Testo completo
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Horlock, J. H. "The Optimum Pressure Ratio for a Combined Cycle Gas Turbine Plant". Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy 209, n. 4 (novembre 1995): 259–64. http://dx.doi.org/10.1243/pime_proc_1995_209_004_01.
Testo completoAbstract (sommario):
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.
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Nguyen, H. B., e A. den Otter. "Development of Gas Turbine Steam Injection Water Recovery (SIWR) System". Journal of Engineering for Gas Turbines and Power 116, n. 1 (1 gennaio 1994): 68–74. http://dx.doi.org/10.1115/1.2906811.
Testo completoAbstract (sommario):
This paper describes and discusses a “closed-loop” steam injection water recovery (SIWR) cycle that was developed for steam-injected gas turbine applications. This process is needed to support gas turbine steam injection especially in areas where water cannot be wasted and complex water treatment is discouraged. The development of the SIWR was initiated by NOVA in an effort to reduce the environmental impact of operating gas turbines and to find suitable solutions for its expanding gas transmission system to meet future air emission restrictions. While turbine steam injection provides many benefits, it has not been considered for remote, less supported environments such as gas transmission applications due to its high water consumption. The SIWR process can alleviate this problem regardless of the amount of injection required. The paper also covers conceptual designs of a prototype SIWR system on a small gas turbine unit. However, because of relatively high costs, it is generally believed that the system is more attractive to larger size turbines and especially when it is used in conjunction with cogeneration or combined cycle applications.