scholarly journals Feasibility of mini combined cycles for naval applications

2018 ◽  
Vol 245 ◽  
pp. 07008 ◽  
Author(s):  
Dario Barsi ◽  
Carlo Costa ◽  
Francesca Satta ◽  
Pietro Zunino ◽  
Vitaly Sergeev
Keyword(s):  
Energy Production ◽  
High Efficiency ◽  
Combined Cycle ◽  
Pollutant Emissions ◽  
Large Power ◽  
Combined Use ◽  
Combined Cycles ◽  
Definition Of ◽  
The Individual ◽  
Near Future

The objective of energy production with low environmental impact will have, in the near future, high potential of development also for naval applications. The containment of pollutant emissions can be achieved by the combined use of an innovative mini gas-steam combined cycle with thermal energy cogeneration to feed the ship thermal utilities, in place of the current Diesel engine application, and liquefied natural gas as fuel (LNG). The present work is focused on the definition of the architecture of the plant, by selecting optimal distribution of pressure and temperature and repartition of power between Gas Turbine (GT), Steam Turbine (ST) and thermal utilities, as well as on the choice and sizing of the individual components. The main purpose is the definition of a compact, high efficiency, system. The proposed basic mini-cycle ranges from 2 MW to 10 MW electric power. Thanks to the combined heat and power cogeneration plant adopted, for an overall electrical efficiency of about 30%, a total return (thermal + electricity) of about 75% can be achieved. An example of plant providing large power, in a partially modular arrangement is also proposed.

Analysis of Intermediate Temperature Combined Cycles With a Carbon Dioxide Topping Cycle

2008 ◽  
Author(s):  
R. Chacartegui ◽  
D. Sa´nchez ◽  
F. Jime´nez-Espadafor ◽  
A. Mun˜oz ◽  
T. Sa´nchez
Keyword(s):  
Carbon Dioxide ◽  
Power Plant ◽  
Gas Turbine ◽  
High Efficiency ◽  
Solar Power ◽  
Combined Cycle ◽  
Inlet Temperature ◽  
Pressure Drops ◽  
Combined Cycles ◽  
Topping Cycle

The development of high efficiency solar power plants based on gas turbine technology presents two problems, both of them directly associated with the solar power plant receiver design and the power plant size: lower turbine intake temperature and higher pressure drops in heat exchangers than in a conventional gas turbine. To partially solve these problems, different configurations of combined cycles composed of a closed cycle carbon dioxide gas turbine as topping cycle have been analyzed. The main advantage of the Brayton carbon dioxide cycle is its high net shaft work to expansion work ratio, in the range of 0.7–0.85 at supercritical compressor intake pressures, which is very close to that of the Rankine cycle. This feature will reduce the negative effects of pressure drops and will be also very interesting for cycles with moderate turbine inlet temperature (800–1000 K). Intercooling and reheat options are also considered. Furthermore, different working fluids have been analyzed for the bottoming cycle, seeking the best performance of the combined cycle in the ranges of temperatures considered.

Analysis of Extended Environomic Cost Influence on Conventional Energy Systems Design

2000 ◽  
Author(s):  
R. Borchiellini ◽  
M. Calì ◽  
M. Santarelli
Keyword(s):  
High Efficiency ◽  
Systems Design ◽  
Energy Systems ◽  
Policy Instrument ◽  
Combined Cycle ◽  
Energy Resources ◽  
Environmental Cost ◽  
Pollutant Emissions ◽  
High Investment ◽  
Economic Balance

Abstract In the paper the authors analyse how the application of an extended environomic procedure, based on charges linked to the pollutant activities of energy systems, influences the energy behaviour of energy systems. If in the economic balance of an energy plant a cost is assigned only to the pollutant emissions (Environmental Cost), it can be shown that this choice allows a good promotion of the abatement devices and of the switching fuel approach, but the efficient utilization of energy resources is not sufficiently promoted. The extended approach, here analysed, takes into account both the pollutant emissions and the inefficient use of energy resources. In the proposed method, on the basis of thermodynamic considerations, a cost is assigned to the exergy rate destroyed inside the system and to the exergy flows rejected into the biosphere with the plant wastes (Efficiency Penalty). Many calculations have been developed using different sets of both the Environmental Cost and the Efficiency Penalty; assigning different weights to them. The calculations have been applied to a 30 MWel gas turbine cogeneration power plant (CGAM), and to an existing 350 MW combined cycle, considering the pollutant emissions of CO, NOx, SOx and CO2. The obtained results show that this approach can become a real energy policy instrument: in fact it allows to stimulate high efficiency design of conventional plants and advanced high-efficiency low-pollutant energy systems, becoming an opportunity to disseminate advanced technologies that still have difficulties to compete in the energy market due to their high investment costs.

scholarly journals Individual psychological characteristics of personality as correlates of executive activity of university students

2019 ◽  
Vol 70 ◽  
pp. 07007
Author(s):  
Alana Uzdenova
Keyword(s):  
Quality Of Life ◽  
High Efficiency ◽  
Personality Development ◽  
Psychological Characteristics ◽  
Professional Activity ◽  
Emotional Lability ◽  
High Quality ◽  
Definition Of ◽  
The Individual

The theory of the executive activity of a personality and the ability to determine its correlates are analyzed. High efficiency executive activity is considered as a predictor of a high quality of life and professional activity of an individual. The results of the study of the individual psychological properties of the personality associated with the characteristics of performing activities are presented. A combination of properties is highlighted: irritability, sociability, extraversion, which positively affect the type of execution. They form a triad closely associated with all the properties of executive activities. Some personality properties that inhibit the development of characteristics necessary for effectiveness are identified. Aggressiveness and high emotional lability are characteristic of students with low responsibility. According to the research results, mutually exclusive properties are organization and openness. The definition of determinants and correlates of performing activities opens up opportunities for psychologists and educators to create spaces for the development of a highly effective personality. Executive activity is a system construct. Understanding its structure allows us to see its flexibility and form individual trajectories of learning and personality development.

scholarly journals Externally Fired Combined Cycles (EFCC): Part A — Thermodynamics and Technological Issues

1996 ◽  
Author(s):  
Stefano Consonni ◽  
Ennio Macchi ◽  
Francesco Farina
Keyword(s):  
Atmospheric Pressure ◽  
Gas Turbines ◽  
Large Scale ◽  
High Efficiency ◽  
Combined Cycle ◽  
Indirect Contact ◽  
Economic Issues ◽  
Combustion Gases ◽  
Combined Cycles ◽  
Gas Turbine Compressor

Externally Fired Combined Cycles (EFCC) are one of the options allowing the use of “dirty” fuels like coal, biomass or waste in conjunction with modern, high efficiency gas turbines. The plant concept comprises an indirect-contact ceramic heat exchanger where compressed air exiting the gas turbine compressor is heated by hot combustion gases; the combustor is placed downstream the turbine and operates at nearly atmospheric pressure. From a thermodynamic standpoint, the cycle is equivalent to a combined cycle with supplementary firing. Attainable efficiencies are higher than those achievable by steam cycles (even the most advanced ultra-supercritical), as well as those of most other coal-based technologies (PFBC and IGCC). These efficiency advantages must be weighted against the uncertainty (and risk) of the realization of high temperature ceramic heat exchangers, and the challenges for the design of the combustor. This two-part paper discusses thermodynamic, technological and economic issues crucial to the success of EFCCs, both for large scale utility service (3–400 MWe1 and more) and for medium/low scale applications (down to 30–50 MWe1). Part A addresses the most relevant thermodynamic and technological issues, performing comparisons with the technologies which will presumably dominate the coal-based power generation market of the next century.

scholarly journals Exergy analysis of combined cycle of gas turbine and solid oxide fuel cell in different compression ratios

2016 ◽  
Vol 4 (2) ◽  
pp. 43
Author(s):  
Esmaeel Fatahian ◽  
Navid Tonekaboni ◽  
Hossein Fatahian
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Gas Turbine ◽  
Energy Production ◽  
High Efficiency ◽  
Production Systems ◽  
New Technology ◽  
Electrical Energy ◽  
Combined Cycle ◽  
Advantages And Disadvantages

Due to the growing trend of energy consumption in the world uses of methods and new energy production systems with high efficiency and low emissions have been prioritized. Today, with the development of different systems of energy production, different techniques such as the use of solar energy, wind energy, fuel cells, micro turbines and diesel generators in cogeneration have been considered, each of these methods has its own advantages and disadvantages. Having a reliable energy generation system, inexpensive and availability the use of fuel cells as a major candidate has been introduced. Fuel cells converting chemical energy to electrical energy that today are one as a new technology in energy production are considered. In this paper fuel cell compression ratios 4, 4.1 and 4.2 at an ambient temperature of 298 K have been simulated and ultimately optimum ratio 4.1 for modeling has been selected. All components of cycle, including the stack of fuel cell, combustion chamber, air compressors, recuperator and gas turbine was evaluated from the viewpoint of exergy and exergy destruction rate was calculated by EES software.

scholarly journals Flexibilization of Gas Turbine Combined Cycle via Heat Pump: development of control logics via Software-in-the-loop application

2019 ◽  
Vol 113 ◽  
pp. 01004 ◽  
Author(s):  
Iacopo Rossi ◽  
Adrien Reveillere ◽  
Alberto Traverso
Keyword(s):  
Power Plant ◽  
Gas Turbine ◽  
Heat Pump ◽  
Energy Production ◽  
Combined Cycle ◽  
Real Field ◽  
Production Environment ◽  
Exchange Information ◽  
Plant Operations ◽  
Near Future

Flexibilization of Gas Turbine Combined Cycle (GTCC) is a key for plant operations in the present as well as in the near future. The increasing of non-dispatchable sources in the energy production environment causes strong fluctuations in energy price and energy production profiles. The opportunity to enhance flexibility of traditional GTCC is consequenlty welcomed. This work focuses on integration of a Heat Pump in a GTCC devoted to cogenerative purpose with the goal to integrate energy production, assist the power plant in normal operations and enriches the transient capability of the whole compound. This approach can be developed to be retro-fitted to existing power plant. In particular, a software-in-the-loop (SiL) application is here presented to test the developed control logics governing such power plant. The power plant model is developed and runs under Siemens AMESIM environemnt, whilst the control system is developed and integrated in Matlab/Simulink environment. The two systems are intefraced and exchange information with the goal to verify reliability of the control logics before going into the real field..

Combined Cycles—Alternative for Process Steam Systems

1983 ◽  
Vol 105 (3) ◽  
pp. 396-400
Author(s):  
H. L. Harkins
Keyword(s):  
High Efficiency ◽  
Economic Incentives ◽  
Combined Cycle ◽  
Operating Costs ◽  
Steam Generators ◽  
Turbine Generator ◽  
Cycle System ◽  
Cycle Systems ◽  
Industry Practice ◽  
Combined Cycles

The state-of-the-art combined cycle system consisting of combustion turbines, heat recovery steam generators, and steam turbine-generator units, offers a high-efficiency method for the production of electrical and heat energy at relatively low installed and operating costs. Regional fuel usage projections for major petrochemical areas of the country indicate a substantial continued usage of lighter fuels for the next 15 to 20 yr by electric utilities and industrials. Only the highest efficiency utilization of these premium fuels should be considered, and this paper discusses systems for this higher utilization. Typical plant systems are compared to more efficient systems, the relative economic incentives are considered, applications for specific requirements representative of industry practice are developed, and alternative fuel considerations for combined cycle systems are included.

MODELING AND SIMULATION OF THERMOELECTRIC PLANT OF COMBINED CYCLES AND ITS ENVIRONMENTAL IMPACT

2005 ◽  
Vol 4 (1) ◽  
pp. 83
Author(s):  
J. F. Mitre ◽  
A. I. Lacerda ◽  
R. F. De Lacerda
Keyword(s):  
Power Plant ◽  
High Efficiency ◽  
Waste Heat ◽  
Combined Cycle ◽  
Steam Power ◽  
Operational Conditions ◽  
Thermoelectric Plant ◽  
Combined Cycles ◽  
Absolute Quantity ◽  
The Impact

The impact any power plant has upon the environment must be minimized as much as possible. Due to its high efficiency, low emission levels and low cooling requirements, combined cycle plants are considered to be environmentally friendly. This study evaluates the effect of operational conditions on pollutants (CO, CO2, SOx, NOx) emissions levels, waste-heat and wastewater of a combined-cycle natural gas and steam power plant. The HYSYS process simulation was used for modelling and simulation. The study clearly shows that the absolute quantity of pollutants emitted is high. Also, it was possible to verify that the unit operate in the condition of minimal emissions regarding the maximum possible, and thus a reduction or elimination of such pollutants is not possible.

scholarly journals 24. Photographic Astrometry

1982 ◽  
Vol 18 (1) ◽  
pp. 237-240
Author(s):  
Heinrich Eichhorn
Keyword(s):  
Proper Motions ◽  
Direct Imaging ◽  
Subject Areas ◽  
The Subject ◽  
Definition Of ◽  
The Individual ◽  
Areas Of Interest ◽  
Near Future

The name of this commission was recently changed from “Parallaxes and Proper Motions”. These data are at this time indeed obtained mostly by the techniques of photographic astrometry, but so is the bulk of relative star positions. It is clear, however, that the nonabsolute determination of relative positions and data derived from them in narrow fields (which describes the scope of this Commission) is going to be carried out more and more also by nonphotographic methods, namely photoelectrically (Earth and satellite based) by interferometry (optical, radio, and speckle) and by direct imaging. This therefore creates considerable overlap with the subject areas and methods of a number of other Commissions, especially Commission 8, and it will be appropriate for Commission 24 in the near future to examine critically the overlapping areas of interest and to come to an agreement about the definition of the proper responsibilities of the individual commissions.

scholarly journals Use of Artificial Neural Networks for the Simulation of Combined Cycle Transients

1997 ◽  
Author(s):  
Umberto Desideri ◽  
Francesco Fantozzi ◽  
Gianni Bidini ◽  
Philippe Mathieu
Keyword(s):  
Neural Networks ◽  
Monitoring System ◽  
Combined Cycle ◽  
Pollutant Emissions ◽  
Plant Performance ◽  
Load Range ◽  
On Line ◽  
Transient Data ◽  
Combined Cycles ◽  
Economic Assets

Due to techno-economic assets, the demand of combined cycles (CC) is currently growing. Nowadays, in a diversified electricity mix, these plants are often used on a load cycling duty or in the intermediate load range. The ability to start quickly and reliably may be a decisional criterion for the selection of the plant, in addition to the design performance, the cost and the pollutant emissions. Therefore, together with the simulation of CC transients, a proper monitoring system aimed at keeping high plant performance during the transients is required. With the help of advanced measurement and monitoring devices, artificial intelligence (AI) techniques as expert systems (ES) and neural networks (NN) can fulfill this duty. The goal of this paper is to show that a NN technique can be used reliably to obtain the response of a complex energetic system, such as CCs, during a slow transient and consequently as part of an on-line monitoring system. In this work, a CC power plant is simulated by dividing it into three blocks, which are representative of the three main elements of the CC: namely the gas turbine (GT), the heat recovery steam generator (HRSG) and the steam turbine (ST). To each of them a NN is associated. Once the training and testing of the NNs is carried out, the blocks are then arranged in a series cascade, the output of a block being the input of the subsequent one. With this solution, the NN-based system is able to produce the transient response of a CC plant when the input information are the GT inlet parameters. The transient data, not easy to obtain from measurements on existing plants, are provided by the CCDYN simulator (Dechamps, 1995). The performance obtained by the NN based system are observed to be in good agreement with those given by CCDYN, the latter being validated on the basis of measurements in an existing plant. The NN code, providing the departures of the measured data from the predicted ones, can be considered as a proper system for on-line monitoring and diagnosis.

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