The Role of High Temperature Gas Turbines in Power Generation

Author(s):  
J. F. Barnes

The purpose of this paper is to examine some possibilities for achieving high gas temperatures in the turbines of both open-cycle and closed-cycle plant and to show how some of the experience gained from research, development, and design of internally cooled blading for aero-engines can be applied to industrial power generation. For the short-term future, preferred schemes would seem to embrace the use of internal air cooling for open-cycle plant and refractory metals without cooling for closed-cycle nuclear plant.

1978 ◽  
Author(s):  
C. F. McDonald

With soaring fuel costs and diminishing clean fuel availability, the efficiency of the industrial gas turbine must be improved by utilizing the exhaust waste heat by either incorporating a recuperator or by co-generation, or both. In the future, gas turbines for power generation should be capable of operation on fuels hitherto not exploited in this prime-mover, i.e., coal and nuclear fuel. The recuperative gas turbine can be used for open-cycle, indirect cycle, and closed-cycle applications, the latter now receiving renewed attention because of its adaptability to both fossil (coal) and nuclear (high temperature gas-cooled reactor) heat sources. All of these prime-movers require a viable high temperature heat exchanger for high plant efficiency. In this paper, emphasis is placed on the increasingly important role of the recuperator and the complete spectrum of recuperative gas turbine applications is surveyed, from lightweight propulsion engines, through vehicular and industrial prime-movers, to the large utility size nuclear closed-cycle gas turbine. For each application, the appropriate design criteria, types of recuperator construction (plate-fin or tubular etc.), and heat exchanger material (metal or ceramic) are briefly discussed.


Author(s):  
Rodger O. Anderson

The generation of electrical power is a complex matter that is dependent in part both on the anticipated demand and the actual amount of power required on the grid. Therefore, the amount of power being generated varies widely depending on the time of day, day of the week, and atmospheric conditions such as cold spells and heat waves. While the amount of power varies, it is recognized that maximum efficiencies are achieved by operating power generation systems at or near steady state conditions. With this in mind, there has been an increased use of gas turbine systems that may be quickly added online to the grid to provide additional power because gas turbine systems are typically well suited for being brought online quickly to provide spinning reserve or electrical generation. However, gas turbines are recognized as not being as efficient as other plant systems such as large steam plants because the gas turbine is an open cycle system where approximately 60 to 70 percent of the energy is lost as exhaust waste heat energy. One recognized method of increasing gas turbine efficiencies is to add a steam bottoming cycle to the exhaust system. However, these closed cycle systems are costly and they compromise the gas turbine’s quick starting capability. This paper discusses an open bottoming cycle that is simple, cost effective and well suited for peaking power generation service. It not only substantially improves the gas turbine simple cycle plant heat rate, but also provides the opportunity to greatly reduce the NOX emissions levels with the application of a low temperature SCR.


Author(s):  
Gulian A. K. Crommelin ◽  
Walter F. Crommelin

Gas turbines in combination with a nuclear heat source have been subject for study for some years. This paper is a logical follow up on previous papers regarding small scale nuclear power generation using gas turbines with a well-proven, inherently safe nuclear heat source. In the Netherlands the NEREUS project has been working on this concept since 1993. The acronym NEREUS describes very well the goals of this project. (Ref 1, 2, 3, 4, 5). NEREUS stands for: a Natural safe, Efficient, Reactor, Easy to operate, Ultimately simple and Small. Current studies focus on the gas turbine part of the installation. After three years of studying the possibilities of the closed cycle helium gas turbine, the NEREUS project returned in 2000 to its original thought of using an existing open-cycle gas turbine or components of such an engine, as energy conversion unit. The paper starts with an introduction on why nuclear power should get more attention, basically explaining “the reasons why” of the NEREUS project. Secondly the paper gives an overview of the main characteristics of the nuclear heat source. Thirdly the paper will discuss the current study to determine the specifications of an open-cycle gas turbine for the NEREUS installation. Attention is given to the way such an open-cycle gas turbine can be controlled. The nuclear heat source is controlled by the laws of physics and it is not recommended to intervene under any circumstances with this very important safety feature.


2005 ◽  
Vol 127 (1) ◽  
pp. 91-99 ◽  
Author(s):  
Michael A. Bartlett ◽  
Mats O. Westermark

Humidified Gas Turbine (HGT) cycles are a group of advanced gas turbine cycles that use water-air mixtures as the working media. In this article, three known HGT configurations are examined in the context of short-term realization for small to midsized power generation: the Steam Injected Gas Turbine, the Full-flow Evaporative Gas Turbine, and the Part-flow Evaporative Gas Turbine. The heat recovery characteristics and performance potential of these three cycles are assessed, with and without intercooling, and a preliminary economic analysis is carried out for the most promising cycles.


Author(s):  
Colin F. McDonald

With the capability of burning a variety of fossil fuels, giving high thermal efficiency, and operating with low emissions, the gas turbine is becoming a major prime-mover for a wide spectrum of applications. Almost three decades ago two experimental projects were undertaken in which gas turbines were actually operated with heat from nuclear reactors. In retrospect, these systems were ahead of their time in terms of technology readiness, and prospects of the practical coupling of a gas turbine with a nuclear heat source towards the realization of a high efficiency, pollutant free, dry-cooled power plant has remained a long-term goal, which has been periodically studied in the last twenty years. Technology advancements in both high temperature gas-cooled reactors, and gas turbines now make the concept of a nuclear gas turbine plant realizable. Two possible plant concepts are highlighted in this paper, (1) a direct cycle system involving the integration of a closed-cycle helium gas turbine with a modular high temperature gas cooled reactor (MHTGR), and (2) the utilization of a conventional and proven combined cycle gas turbine, again with the MHTGR, but now involving the use of secondary (helium) and tertiary (air) loops. The open cycle system is more equipment intensive and places demanding requirements on the very high temperature heat exchangers, but has the merit of being able to utilize a conventional combined cycle turbo-generator set. In this paper both power plant concepts are put into perspective in terms of categorizing the most suitable applications, highlighting their major features and characteristics, and identifying the technology requirements. The author would like to dedicate this paper to the late Professor Karl Bammert who actively supported deployment of the closed-cycle gas turbine for several decades with a variety of heat sources including fossil, solar, and nuclear systems.


Energies ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5604
Author(s):  
Hookyung Lee ◽  
Minjung Lee

With the formation of an international carbon-neutral framework, interest in reducing greenhouse gas emissions is increasing. Ammonia is a carbon-free fuel that can be directly combusted with the role of an effective hydrogen energy carrier, and its application range is expanding. In particular, as research results applied to power generation systems such as gas turbines and coal-fired power plants have been reported, the technology to use them is gradually being advanced. In the present study, starting with a fundamental combustion research case conducted to use ammonia as a fuel, the application research case for gas turbines and coal-fired power plants was analyzed. Finally, we report the results of the ammonia-air burning flame and pulverized coal-ammonia-air co-fired research conducted at the authors’ research institute.


Author(s):  
Antonio Andreini ◽  
Riccardo Da Soghe ◽  
Bruno Facchini

The increase of aero engines performance through the improvement of aerodynamic efficiency of main annulus flow is becoming more and more difficult to achieve. However there are still some devices that could be improved to enhance global engine efficiency. Particularly, investigations on the internal air cooling systems, may lead to a reduction of cooling air with a direct benefit to the overall performance. At the same time, further investigations on heat transfer mechanisms within turbine cavities may help to optimize cooling air flows saving engine life duration. This paper presents a CFD study aimed at the characterization of the effects of different geometries for cooling air supply within turbine cavities on wall thermal effectiveness and sealing mass flow rate. Several sealing air supply geometries were considered in order to point out the role of cooling air injection position, swirl number and jet penetration on the cavities sealing performance. The study was set up on a two-stage axial turbine rig developed in a research programme on internal air systems funded by EU (Main Annulus Gas Path Interactions - MAGPI). Steady state calculations were performed using two different computational domains: the first consists in a sector model of the whole turbine including the second stator well, while the second is a cut-down model of the stator well. Thanks to the simplified geometry of the test rig with respect to actual engines, the study has pointed out clear design suggestions regarding the effects of geometry modification of cooling air supply system.


Author(s):  
Allen D. Harper

Three alternative on-site cogeneration power systems were evaluated against technical and economic criteria for three industrial sites. Technical factors included plant sizing to meet process thermal loads, fuel utilization, power output, siting consideration, fuel savings, etc. Economic factors included capital cost, return on equity, and ownership/financing options among others. Each cogeneration plant was evaluated by comparison with the current separate generation scheme. The technologies considered were 1) conventional coal-fired, steam topping cycles; 2) coal-fired, atmospheric fluidized bed/closed-cycle gas turbines; and 3) coal-fired, atmospheric fluidized bed/open cycle gas turbines. These approaches were optimized for three sites 1) an agricultural chemical plant, 2) a brewery, and 3) a kraft paper mill. The results showed that the closed cycle gas turbines yielded the best economics, primarily due to a lower initial cost. The open cycle gas turbine, when combined with a steam bottoming cycle, resulted in larger power outputs than would be realized in the closed cycle or steam turbine cases. None of the plants studied matched the plant electrical load while following the thermal load.


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