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Dissertations / Theses on the topic 'Combined Cycle'
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1
Muntyan, Andriy. "Combined cycle energy production." Thesis, Видавництво СумДУ, 2008. http://essuir.sumdu.edu.ua/handle/123456789/11779.
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Liang, Hua. "Viability of stirling-based combined cycle distributed power generation." Ohio : Ohio University, 1998. http://www.ohiolink.edu/etd/view.cgi?ohiou1176484842.
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Zwebek, A. I. "Combined Cycle Performance Deterioration Analysis." Thesis, Cranfield University, 2002. http://dspace.lib.cranfield.ac.uk/handle/1826/10462.
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Combined
cycles are subject to degradations and hence performance deterioration.
According to the author's survey nothing was found in the open literature on this
subject. Therefore, it was anticipated that it would be of great achievement if a tool for
analysing and diagnosing the deterioration of combined cycle could be produced. So
this thesis
presents a procedure for combined cycle performance analysis and fault
diagnostic by way of simulation.
l order to
accomplish this task successfully it was necessary to developed two
pieces of software. These are STEAMOMATCH for steam cycle performance
deterioration
analysis, and GOTRESS for GPA of any system. STEAMOMATCH, which
is built on the basics of combined cycle thermodynamics, can simulate up to three levels
of
pressure with reheat. On the other hand GOTRESS uses a Gas Path Analysis
technique that enables the user the choice of conducting either linear or non-linear GPA
at the same time. I both cases single or multiple fault can be diagnosed. GOTRESS
was built in such a
way that it makes it a generalised code that can be used not only for
combined
cycle but to diagnose a wide range of power cycle plants.
The deterioration simulation results of the gas turbine power plant showed that the
isentropic efficiency deterioration of the turbine unit has the uppermost sever effect on
overall
gas turbine power output and thermal efficiency. This is also the case with
steam turbine
(bottoming) cycle power and Rankine efficiency. Also, the simulation
results obtained showed that the relationship between the gas turbine size and its
performance deterioration is almost constant, i.e. performance deterioration follows the
plant's size. Among the two major gas turbine parameters that affects the steam
bottoming cycle performance of a CCGT power plant, the gas turbine exhaust
temperature has a predominant effect on steam cycle efficiency over the exhaust mass
flow.' As a
general result, the obtained simulation results showed that the behaviour of
CCGT
power plant performance is more affected by gas turbine cycle conditions than
by steam turbine cycle conditions. The obtained results showed that GPA can be
successfully applied to either gas turbine cycle, steam turbine cycle, or the combination
of the two in a form of combined cycle. The GPA diagnostic results obtained showed
that it would be
possible to detect some faults that might occur within the gas turbine
that is a
part of a combined cycle power plant by monitoring the dependent parameters
of the steam turbine (bottoming) cycle such as live steam pressure and temperature and
steam turbine
power. In contrast, it would not been possible to detect the problems
(implanted faults) that might occur within the steam turbine by monitoring the
dependent parameters of the gas turbine unit.
4
Colpan, Can Ozgur. "Exergy Analysis Of Combined Cycle Cogeneration Systems." Master's thesis, METU, 2005. http://etd.lib.metu.edu.tr/upload/12605993/index.pdf.
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In this thesis, several configurations of combined cycle cogeneration systems proposed by the author and an existing system, the Bilkent Combined Cycle Cogeneration Plant, are investigated by energy, exergy and thermoeconomic analyses. In each of these configurations, varying steam demand is considered rather than fixed steam demand. Basic thermodynamic properties of the systems are determined by energy analysis utilizing main operation conditions. Exergy destructions within the system and exergy losses to environment are investigated to determine thermodynamic inefficiencies in the system and to assist in guiding future improvements in the plant. Among the different approaches for thermoeconomic analysis in literature, SPECO method is applied. Since the systems have more than one product (process steam and electrical power), systems are divided into several subsystems and cost balances are applied together with the auxiliary equations. Hence, cost of each product is calculated. Comparison of the configurations in terms of performance assessment parameters and costs per unit of exergy are also given in this thesis.
5
Mogavero, Alessandro. "Toward automated design of Combined Cycle Propulsion." Thesis, University of Strathclyde, 2016. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=26892.
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One means to reduce both the cost and the risk associated with space missions is to employ a vehicle designed within the re-usable, airliner-like 'space plane' paradigm. Key to the practicality of such vehicles is the further development of Combined Cycle Propulsion technology. In this thesis, a new engineering tool called the HYbrid PRopulsion Optimizer (HyPro) is presented, with the aim of analysing the performance of diverse engine concepts. The tool is conceived to be modular and flexible, and makes use of parsimonious modelling, in order to describe the engine at an high level of abstraction and to be fast in execution. A configurational optimizer has also been developed in order to automatically generate new design concepts, optimizing the engine cycle structure. It is conceived to be used at the beginning of development in order to perform an automatic and objective trade-off of possible propulsion solutions. In this work the model has been implemented for Rocket-Based Combined Cycle, and it has been verified and validated against analytical models, computational fluid dyanamic analyses and experimental data. The design proposed by the optimizer in these conditions was coherent with manually designed Combined Cycle Propulsion engines, demonstrating the HyPro's capability to converge on good solutions. The results, although preliminary, are very promising and represent a novelty in the field, since a configurational optimization, in the field of propulsion concepts, has never been attempted before. The results presented here demonstrate that the configurational optimization of engine design is viable. The next steps to produce a practical optimizer, which delivers robust and innovative engine solutions, are the addition of modelling capabilities beyond the Rocket-Based Combined Cycle and analysis discipline beyond the pure performances.
6
Colville, Jesse R. "Axisymmetric inlet design for combined cycle engines." College Park, Md. : University of Maryland, 2005. http://hdl.handle.net/1903/2542.
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Thesis (M.S.) -- University of Maryland, College Park, 2005.Thesis research directed by: Dept. of Aerospace Engineering. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Safyel, Zerrin. "Enhancement Of The Bottoming Cycle In A Gas/steam Combined Cycle Power Plant." Master's thesis, METU, 2005. http://etd.lib.metu.edu.tr/upload/2/12605896/index.pdf.
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A combined cycle gas/steam power plant combines a gas turbine (topping cycle) with a steam power plant (bottoming cycle) through the use of a heat recovery steam generator. It uses the hot exhaust of the gas turbine to produce steam which is used to generate additional power in the steam power plant.
The aim of this study is to establish the different bottoming cycle performances in terms of the main parameters of heat recovery steam generator and steam cycle for a chosen gas turbine cycle.
First of allfor a single steam power cycle, effect of main cycle parameters on cycle performance are analyzed based on first law of thermodynamics. Also, case of existence of a reheater section in a steam cycle is evaluated. For a given gas turbine cycle, three different bottoming cycle configurations are chosen and parametric analysis are carried out based on energy analysis to see the effects of main cycle parameters on cycle performance. These are single pressure cycle, single pressure cycle with supplementary firing and dual pressure cycle. Also, effect of adding a single reheat to single pressure HRSG is evaluated. In single pressure cycle, HRSG generates steam at one pressure level. In dual pressure cycle, HRSG generates steam at two different pressure levels. i.e. high pressure and low pressure. In single pressure cycle with supplementary firing excess oxygen in exhaust gas is fired before entering HRSG by additional fuel input. So, temperature of exhaust gas entering the HRSG rises. Second law analysis is performed to able to see exergy distribution throughout the bottoming plant
furthermore second law efficiency values are obtained for single and dual pressure bottoming cycle configurations as well as basic steam power cycle with and without reheat. It is shown that maximum lost work due to irreversibility is in HRSG for a bottoming cycle in a single pressure gas / steam combined power plant and in boiler for a steam cycle alone. Comparing this with the single pressure cycle shows how the dual pressure cycle makes better use of the exhaust gas in the HRSG that dual pressure combined cycle has highest efficiency values and lost work due to irreversibility in -most significant component- HRSG can be lowered. And also it is shown that by extending the idea of reheat the moisture content is reduced and improvement in the performance is possible for high main steam pressures. Another observation is that supplementary firing increases the steam turbine output compared to the cycle without supplementary firing. The efficiency rises slightly for HP steam pressures higher than 14 MPa at HRSG exit, because the increased steam production also results in increased mass flows removing more energy from the exhaust gas.
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Safyel, Zerrin Supervisor :. Yeşin Tülay. "Enhancement of the bottoming cycle in a gas/steam combined cycle power plant." Ankara : METU, 2005. http://etd.lib.metu.edu.tr/upload/2/12605896/index.pd.
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Dogan, Osman Tufan. "Performance Of Combined Cycle Power Plants With External Combustion." Thesis, METU, 2003. http://etd.lib.metu.edu.tr/upload/1223288/index.pdf.
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Hall, Rodney H. F. "Crack growth under combined high and low cycle fatigue." Thesis, University of Portsmouth, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.290404.
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Clough, Joshua Alan. "Modeling and optimization of turbine-based combined-cycle engine performance." College Park, Md. : University of Maryland, 2004. http://hdl.handle.net/1903/2094.
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Thesis (M.S.) -- University of Maryland, College Park, 2004.Thesis research directed by: Dept. of Aerospace Engineering. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Law, Boon-Chuan. "UNCERTAINTY ANALYSIS FOR ROCKET-BASED COMBINED CYCLE (RBCC) SYSTEMS TESTING." MSSTATE, 2003. http://sun.library.msstate.edu/ETD-db/theses/available/etd-07152003-174339/.
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General uncertainty analysis was used to evaluate the performance of a Rocket-Based Combined Cycle (RBCC) engine system. To estimate the uncertainties of test results, uncertainties of basic measurements such as temperature, pressure, mass flow rate, and thrust were determined. The desired test results of interest included specific impulse and characteristic velocity. Various possible test facilities were reviewed to obtain background information and example test run conditions. Based on the test run conditions, five methods of determining specific impulse were evaluated. Also, theoretical and actual characteristic velocities were analyzed to evaluate C* efficiency. Initially, general uncertainty analyses were completed relative to 1% accuracy for each measured variable. Then, cases were run using more realistic uncertainty estimates. The relative contributions of the different variables? uncertainties to the overall uncertainty of the selected performance parameters were also calculated. This process helps to identify the critical measurements from an uncertainty standpoint and can be a significant guide in the cost effective use of resources to reduce the test uncertainty.
13
Tamm, Gunnar Olavi. "Experimental investigation of an ammonia-based combined power and cooling cycle." [Gainesville, Fla.]: University of Florida, 2003. http://purl.fcla.edu/fcla/etd/UFE0000802.
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Bengtsson, Sara. "Modelling of a Power System in a Combined Cycle Power Plant." Thesis, Uppsala universitet, Elektricitetslära, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-149318.
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Simulators for power plants can be used for many different purposes, like training for operators or for adjusting control systems, where the main objective is to perform a realistic behaviour for different operating conditions of the power plant. Due to an increased amount of variable energy sources in the power system, the role of the operators has become more important. It can therefore be very valuable for the operators to try different operating conditions like island operation. The aim of this thesis is to model the power system of a general combined-cycle power plant simulator. The model should contain certain components and have a realistic behaviour but on the same time be simple enough to perform simulations in real time. The main requirements are to simulate cold start, normal operation, trip of generator, a controlled change-over to island operation and then resynchronisation. The modelling and simulations are executed in the modelling software Dymola, version 6.1. The interface for the simulator is built in the program LabView, but that is beyond the scope of this thesis. The results show a reasonable performance of the power system with most of the objectives fulfilled. The simulator is able to perform a start-up, normal load changes, trip of a generator, change-over to island operation as well as resynchronisation of the power plant to the external power grid. However, the results from the changing-over to island operation, as well as large load losses during island operation, show an unreasonable behaviour of the system regarding the voltage magnitude at that point. This is probably due to limitations in calculation capacity of Dymola, and the problem has been left to further improvements due to lack of time. There has also been a problem during the development of a variable speed regulated induction motor and it has not been possible to make it work due to lack of enough knowledge about how Dymola is performing the calculations. Also this problem has been left to further improvements due to lack of time.
15
Kandil, Sherif M. "Analysis and optimization of a jet-pumped combined power/refrigeration cycle." [Gainesville, Fla.] : University of Florida, 2006. http://purl.fcla.edu/fcla/etd/UFE0013733.
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Rosso, Stefano. "Power Plant Operation Optimization Economic dispatch of combined cycle power plants." Thesis, KTH, Skolan för industriell teknik och management (ITM), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-264350.
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As electricity production from renewable sources increases, higher flexibility is required by fossil fuel generation to cope with the inherent fluctuations of solar and wind power. This results in shorter operating cycles and steeper ramps for the turbines, and more uncertainty for the operators. This thesis work applies mathematical optimization and statistical learning to improve the economic dispatch of a combined cycle power plant composed by two separate blocks of two gas turbines and one steam turbine. The goal is to minimize the input fuel to the gas turbines while respecting a series of constraints related to the demand the plant faces, power generation limits etc. This is achieved through the creation of a mathematical model of the plant that regulates how the plant can operate. The model is then optimized to reduce fuel consumption at a minimum. Machine learning techniques have been applied to sensor data from the plant itself to realistically simulate the behavior of the turbines. Input-Output curves have been obtained for power and exhaust heat generation of all the turbines using ordinary least squares on monthly data with a ten minutes sampling rate. The model is cross-validated and proven statistically valid. The optimization problem is formulated through generalized disjunctive programming in the form of a mixed-integer linear problem (MILP) and solved using a branch-and-bound algorithm. The output of the model is a one-week dispatch, in fifteen minutes intervals, carried out for two months in total. Lower fuel consumption is achieved using the optimization model, with a weekly reduction of fuel consumed in the range of 2-4%. A sensitivity analysis and a correlation matrix are used to highlights the demand and the maximum available capacity as critical parameters. Results show that the most efficient machines (alternatively, the ones with highest available capacity) should be operated at maximum load while still striving for an efficient utilization of the exhaust gas.När elproduktionen från förnybara källor ökar krävs högre flexibilitet av fossil bränsleproduktion för att hantera fluktuationerna från sol- och vindkraft. Detta resulterar i kortare driftscykler och brantare ramper för turbinerna och mer osäkerhet för operatörerna. Detta avhandlingsarbete tillämpar matematisk optimering och statistisk inlärning för att förbättra det ekonomiska utnyttjandet av en kombicykel i ett kraftverk som består av två separata block med två gasturbiner och en ångturbin. Målet är att minimera bränsleförbrukningen hos gasturbinerna samtidigt som man tar hänsyn till en serie av villkor relaterade till efterfrågan som anläggningen står inför, kraftproduktionsbegränsningar etc. Detta uppnås genom skapandet av en matematisk modell för anläggningen som reglerar hur anläggningen kan fungera. Modellen är sedan optimerad för minsta möjliga bränsleförbrukning. Maskinteknik har använts på sensor data från själva anläggningen för att realistiskt simulera turbinernas beteende. In och utdata kurvor har erhållits för kraftproduktion och avgasvärmeproduktion med hjälp av ordinary least squares (OLS) med månads data och med en tio minuters samplingshastighet. Modellen är korsvaliderad och bevisad statistiskt giltig. Optimeringsproblemet formuleras genom en generaliserad disjunktiv programmering i form av ett mixed-integer linear problem (MILP) och löses med hjälp av en Branch-and-Bound algoritm. Resultatet från modellen är en veckas värden, med femton minuters intervall, totalt i två månader. Lägre bränsleförbrukning uppnås med hjälp av optimeringsmodellen, med en vecka minskad bränsleförbrukning i intervallet 2-4%. En känslighetsanalys och en korrelationsmatris används för att visa efterfrågan och den maximala tillgängliga kapaciteten som kritiska parametrar. Resultaten visar att de mest effektiva maskinerna (alternativt de med högsta tillgängliga kapacitet) bör drivas med maximal belastning medan de fortfarande strävar efter ett effektivt utnyttjande av avgaserna.
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Bhatt, Dhruv. "Economic Dispatch of the Combined Cycle Power Plant Using Machine Learning." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-266110.
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Combined Cycle Power Plant (CCPP)s play a key role in modern powersystem due to their lesser investment cost, lower project executiontime, and higher operational flexibility compared to other conventionalgenerating assets. The nature of generation system is changing withever increasing penetration of the renewable energy resources. Whatwas once a clearly defined generation, transmission, and distributionflow is shifting towards fluctuating distribution generation. Because ofvariation in energy production from the renewable energy resources,CCPP are increasingly required to vary their load levels to keep balancebetween supply and demand within the system. CCPP are facingmore number of start cycles. This induces more stress on the gas turbineand as a result, maintenance intervals are affected.The aim of this master thesis project is to develop a dispatch algorithmfor the short-term operation planning for a combined cyclepower plant which also includes the long-term constraints. The longtermconstraints govern the maintenance interval of the gas turbines.These long-term constraints are defined over number of EquivalentOperating Hours (EOH) and Equivalent Operating Cycles (EOC) forthe Gas Turbine (GT) under consideration. CCPP is operating in theopen electricity market. It consists of two SGT-800 GT and one SST-600 Steam Turbine (ST). The primary goal of this thesis is to maximizethe overall profit of CCPP under consideration. The secondary goal ofthis thesis it to develop the meta models to estimate consumed EOHand EOC during the planning period.Siemens Industrial Turbo-machinery AB (SIT AB) has installed sensorsthat collects the data from the GT. Machine learning techniqueshave been applied to sensor data from the plant to construct Input-Output (I/O) curves to estimate heat input and exhaust heat. Resultsshow potential saving in the fuel consumption for the limit on CumulativeEquivalent Operating Hours (CEOH) and Cumulative EquivalentOperating Cycles (CEOC) for the planning period. However, italso highlighted some crucial areas of improvement before this economicdispatch algorithm can be commercialized.Kombicykelkraftverk spelar en nyckelroll i det moderna elsystemet pågrund av den låga investeringskostnaden, den korta tiden för att byggaett nytta kraftverk och hög flexibilitet jämfört med andra kraftverk.Elproduktionssystemen förändras i takt med en allt större andel förnybarelproduktion. Det som en gång var ett tydligt definierat flödefrån produktion via transmission till distribution ändrar nu karaktärtill fluktuerande, distribuerad generering. På grund av variationernai elproduktion från förnybara energikällor finns ett ökat behov avatt kombicykelkraftverk varierar sin elproduktion för att upprätthållabalansen mellan produktion och konsumtion i systemet. Kombicykelkraftverkbehöver startas och stoppas oftare. Detta medför mer stresspå gasturbinen och som ett resultat påverkas underhållsintervallerna.Syftet med detta examensarbete är att utveckla en algoritm för korttidsplaneringav ett kombicykelkraftverk där även driften på lång siktbeaktas. Begränsningarna på lång sikt utgår från underhållsintervallenför gasturbinerna. Dessa långsiktiga begränsningar definieras som antaletekvivalenta drifttimmar och ekvivalenta driftcykler för det aktuellakraftverket. Kombikraftverket drivs på den öppna elmarknaden.Det består av två SGT-800 GT och en SST-600 ångturbin. Det främstamålet med examensarbetet är att maximera den totala vinsten förkraftverket. Ett sekundärt mål är att utveckla metamodeller för attskatta använda ekvivalenta drifttimmar och ekvivalenta driftcyklerunder planeringsperioden.Siemens Industrial Turbo-machinery AB (SIT AB) har installeratsensorer som samlar in data från gasturbinerna. Maskininlärningsteknikerhar tillämpats på sensordata för att konstruera kurvor för attuppskatta värmetillförseln och avgasvärme. Resultaten visar en potentiellbesparing i bränsleförbrukningen om de sammanlagda ekvivalentadrifttimmarna och de sammanlagda ekvivalenta driftcyklernabegränsas under planeringsperioden. Det framhålls dock också att detfinns viktiga förbättringar som behövs innan korttidsplaneringsalgoritmenkan kommersialiseras.
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Oelofse, Stephanus Phillipus. "An investigation into the performance of a Rankine-heat pump combined cycle / Stephanus Phillipus Oelofse." Thesis, North-West University, 2012. http://hdl.handle.net/10394/9185.
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The global growth in electricity consumption and the shortcomings of renewable electricity generation technologies are some of the reasons why it is still relevant to evaluate the performance of power conversion technologies that are used in fossil fuel power stations.
The power conversion technology that is widely used in fossil fuel power stations is the Rankine cycle. The goal of this study was to determine if the efficiency of a typical Rankine cycle can be improved by adding a heat pump as a bottoming cycle. Three simulation models were developed to perform this evaluation.
The first is a simulation model of a Rankine cycle. A quite detailed Rankine cycle configuration was evaluated. The simulation model was used to determine the heating requirements of the heat pump cycle as well as its operating temperature ranges. The efficiency of this Rankine cycle was calculated as 43.05 %.
A basic vapour compression cycle configuration was selected as the heat pump of the combined cycle. A simulation model of the vapour compression cycle and the interfaces with the Rankine cycle was developed as the second simulation model.
Working fluids that are typically used in vapour compression cycles cannot be used for this application, due to temperature limitations. The vapour compression cycle’s simulation model was therefore also used to calculate the coefficient of performance (COP) for various working fluids in order to select a suitable working fluid. The best cycle COP (3.015 heating) was obtained with ethanol as working fluid.
These simulation models were combined to form the simulation model of the Rankine-heat pump combined cycle. This model was used to evaluate the performance of the combined cycle for two different compressor power sources.
This study showed that the concept of using steam turbine or electrical power to drive a compressor driven vapour compression cycle in the configuration proposed here does not improve the overall efficiency of the cycle.
The reasons for this were discovered and warrant future investigation.Thesis (MIng (Mechanical Engineering))--North-West University, Potchefstroom Campus, 2013.
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Petrov, Miroslav. "Biomass and Natural Gas Hybrid Combined Cycles." Licentiate thesis, KTH, Energy Technology, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-1660.
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Biomass is one of the main natural resources in Sweden.Increased utilisation of biomass for energy purposes incombined heat and power (CHP) plants can help the country meetits nuclear phase-out commitment. The present low-CO2 emissioncharacteristics of the Swedish electricity production system(governed by hydropower and nuclear power) can be retained onlyby expansion of biofuels in the CHP sector. Domestic Swedishbiomass resources are vast and renewable, but not infinite.They should be utilised as efficiently as possible in order tomeet the conditions for sustainability in the future.Application of efficient power generation cycles at low cost isessential for meeting this challenge. This applies also tomunicipal solid waste (MSW) incineration with energyextraction, which is to be preferred to landfilling.
Modern gas turbines and internal combustion engines firedwith natural gas have comparatively low installation costs,good efficiency characteristics and show reliable performancein power applications. Environmental and source-of-supplyfactors place natural gas at a disadvantage as compared tobiofuels. However, from a rational perspective, the use ofnatural gas (being the least polluting fossil fuel) togetherwith biofuels contributes to a diverse and more secure resourcemix. The question then arises if both these fuels can beutilised more efficiently if they are employed at the samelocation, in one combined cycle unit.
The work presented herein concentrates on the hybriddual-fuel combined cycle concept in cold-condensing and CHPmode, with a biofuel-fired bottoming steam cycle and naturalgas fired topping gas turbine or engine. Higher electricalefficiency attributable to both fuels is sought, while keepingthe impact on environment at a low level and incorporating onlyproven technology with standard components. The study attemptsto perform a generalized and systematic evaluation of thethermodynamic advantages of various hybrid configurations withthe help of computer simulations, comparing the efficiencyresults to clearly defined reference values.
Results show that the electrical efficiency of hybridconfigurations rises with up to 3-5 %-points in cold-condensingmode (up to 3 %-points in CHP mode), compared to the sum of twosingle-fuel reference units at the relevant scales, dependingon type of arrangement and type of bottoming fuel. Electricalefficiency of utilisation of the bottoming fuel (biomass orMSW) within the overall hybrid configuration can increase withup to 8-10 %-points, if all benefits from the thermalintegration are assigned to the bottoming cycle and effects ofscale on the reference electrical efficiency are accounted for.All fully-fired (windbox) configurations show advantages of upto 4 %-points in total efficiency in CHP mode with districtheating output, when flue gas condensation is applied. Theadvantages of parallel-powered configurations in terms of totalefficiency in CHP mode are only marginal. Emissions offossil-based CO2 can be reduced with 20 to 40 kg CO2/MWhel incold-condensing mode and with 5-8 kg CO2 per MWh total outputin CHP mode at the optimum performance points.
Keywords: Biomass, Municipal Solid Waste (MSW), Natural Gas,Simulation, Hybrid, Combined Cycle, Gas Turbine, InternalCombustion Engine, Utilization, Electrical Efficiency, TotalEfficiency, CHP.
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Kloppers, Cornelius Petrus. "Thermodynamic cycle design of a Brayton–Rankine combined cycle for a pebble bed modular reactor / Cornelius Petrus Kloppers." Thesis, North-West University, 2011. http://hdl.handle.net/10394/7623.
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The rapid development in nuclear technology worldwide has created the need for an efficient power conversion unit to extract the energy from the new generation IV reactors. The generation IV reactor currently under investigation in South Africa is the PBMR–DPP (Pebble Bed Modular Reactor Demonstration Power Plant) based on the High temperature Reactor Modul. This reactor produces 200 MW of thermal energy at inlet/outlet temperatures of 250oC/700oC. Due to the reactor layout and accompanying thermal fluid path design outlet temperatures in the order of 900oC would be possible. This dissertation is aimed at the design and optimisation of a Brayton–Rankine combined cycle for use with a PBMR–DPP. The combination of these two cycles improves the thermal efficiency due to the large difference between the maximum and minimum temperatures. The Brayton and Rankine cycles will be developed independently and optimised to ensure that the best possible efficiency is gained from the combined cycle. The heat energy available in the reactor is the input parameter for the Brayton cycle, After the Brayton cycle's pressure ratio has been optimised the heat rejected to the Rankine cycle will be known. The aim of the design is to determine if 50% combined cycle thermal efficiency is achievable. The initial sizing calculation of the cycle parameters has been done in a software package that has been developed for use in the thermo–hydraulics field. Engineering Equation Solver (EES) makes use of an iterative process to simultaneously solve the set of equations. The results obtained from EES were verified by Microsoft Excel with a specialised macro installed for thermo–hydraulics.
A very specific methodology was used to solve the Brayton cycle. Traditionally the Brayton cycle is optimised for maximum cycle efficiency to ultimately obtain the best combined cycle efficiency. Very complex cycles such as reheat and multi–shaft Brayton cycles were used. The solution methodology used in this dissertation is to optimise the simple Brayton cycle for the maximum specific work produced in the cycle. The large amount of heat at the turbine outlet is then transferred to the Rankine cycle. The results obtained from the calculations preformed were that a combined cycle efficiency of 52.914% has been achieved at optimum operating conditions. The combined cycle has been shown to operate above 50% efficiency in a wide variety of load–following conditions.Thesis (M.Ing. (Mechanical Engineering))--North-West University, Potchefstroom Campus, 2011.
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Govindaraju, Sirisha D. "Analysis of absorber operations for the 5 kw ammonia/water combined cycle." [Gainesville, Fla.] : University of Florida, 2005. http://purl.fcla.edu/fcla/etd/UFE0010828.
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Horkeby, Kristofer. "Simulation of Heat Recovery Steam Generator in a Combined Cycle Power Plant." Thesis, Linköpings universitet, Institutionen för systemteknik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-75836.
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This thesis covers the modelling of a Heat Recovery Steam Generator (HRSG) in a Combined Cycle Power Plant(CCPP). This kind of power plant has become more and more utilized because of its high efficiency and low emissions. The HRSG plays a central role in the generation of steam using the exhaust heat from the gas turbine. The purpose of the thesis was to develop efficient dynamic models for the physical components in the HRSG using the modelling and simulation software Dymola. The models are then to be used for simulations of a complete CCPP.The main application is to use the complete model to introduce various disturbances and study their consequences inthe different components in the CCPP by analyzing the simulation results. The thesis is a part of an ongoingdevelopment process for the dynamic simulation capabilities offered by the Solution department at SIT AB. First, there is a theoretical explanation of the CCPP components and control system included in the scope of this thesis. Then the development method is described and the top-down approach that was used is explained. The structure and equations used are reported for each of the developed models and a functional description is given. Inorder to ensure that the HRSG model would function in a complete CCPP model, adaptations were made and tuning was performed on the existing surrounding component models in the CCPP. Static verifications of the models are performed by comparison to Siemens in-house software for static calculations. Dynamic verification was partially done, but work remains to guarantee the validity in a wide operating range. As a result of this thesis efficient models for the drum boiler and its control system have been developed. An operational model of a complete CCPP has been built. This was done integrating the developed models during the work with this thesis together with adaptations of already developed models. Steady state for the CCPP model is achieved during simulation and various disturbances can then be introduced and studied. Simulation time for a typical test case is longer than the time limit that has been set, mainly because of the gas turbine model. When using linear functions to approximate the gas turbine start-up curves instead, the simulation finishes within the set simulation time limit of 5 minutes for a typical test case.
23
Moradi, Mohammed Hasan. "New modelling and control methods with application to combined cycle power plants." Thesis, University of Strathclyde, 2002. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=21157.
Full textAbstract:
This thesis reports the analysis and modelling required to build a software simulation of combine cycle power plants. A new MIMO PID controller tuning method and a novel predictive PID controller design method for MIMO systems are also described in the thesis. The emphasis of this work is on simulation; identification and controller design methods. The thesis begins with an account of the combined cycle power plant modelling and simulation development. This culminates in a library of different blocks and subsystems of combined cycle power plants. The simulation development shows how the steady state and dynamic behaviour of combined cycle power plants can be simulated and implemented in the SMULINK and MATLAB environment using per unit models, which are suitable for control design. In the identification stage, the relay identification method is used to identify the critical points of the system for a newly defined criterion at bandwidth frequency. Then, the identified critical points are used to tune PID controllers. The thesis then outlines multivariable PID tuning methods and makes a comparison between these methods and the new relay identification method concerning their robustness for MIMO systems. The last two chapter of thesis are concerned with a new predictive PID controller design method for both SISO and MIMO systems. This methodology is concerned with the design of PID controllers, which have similar features to the model-based predictive controller. Generalized Predictive Control (GPC) design principles are used to develop the PID control with predictive capabilities for both SISO and MIMO systems. The combined cycle power plant simulation, especially the boiler subsystem, is used as an example throughout the thesis.
24
PINTO, RAPHAEL GUIMARAES DUARTE. "SIMULATION OF HEAT RECOVERY STEAM GENERATOR OPERATING IN A COMBINED CYCLE PLANT." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2012. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=20769@1.
Full textAbstract:
PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROA evolução das turbinas a gás industriais resultou em um processo de combustão mais eficiente que permitiu a elevação da temperatura dos gases na exaustão dessa máquina. Assim, caldeiras de recuperação de calor cada vez mais complexas foram desenvolvidas com o intuito de aproveitar ao máximo o potencial energético na exaustão das turbinas. Dessa forma, modelos computacionais capazes de prever as condições de operação do equipamento se mostraram necessários de maneira a analisar o comportamento da máquina em diferentes situações, visando à máxima eficiência do processo. Esta dissertação descreve um modelo computacional capaz de simular o funcionamento fora do ponto de projeto, em regime permanente, de uma caldeira de recuperação de calor operando em uma usina de ciclo combinado, enfatizando sua utilização em sistemas de diagnóstico. As rotinas foram desenvolvidas em FORTRAN e os trocadores de calor presentes na HRSG foram modelados individualmente e calibrados através de um sistema de otimização utilizando algoritmos genéticos, responsável por minimizar o desvio do modelo. O programa desenvolvido foi validado contra dados de operação de uma usina real e mostrou resultados satisfatórios, que confirmam a robustez e fidelidade do modelo de simulação.
The heavy duty gas turbines evolution and, consequently, a more efficient combustion process, allowed the temperature rising of the machines’ exhaust gases. Thus, more complex heat recovery steam generators were developed in order to maximize the use of that energy potential. Therefore, computational models capable to predict the operational conditions of the equipment may be needed in order to analyze the machine’s behavior for different situations, in a way to maximize the process efficiency. This thesis describes a computational model able to simulate the off-design behavior of a heat recovery steam generator operation in a combined cycle plant, emphasizing its utilization in diagnostics systems. The routines were developed using FORTRAN, each heat exchanger inside the Heat Recovery Steam Generator (HRSG) was designed individually and the calibration was done by a genetic algorithm responsible for minimizing the model’s deviations. The developed program was validated against operational data from a real plant and showed satisfactory results, confirming the robustness and fidelity of this simulation model.
25
Smith, P. J. "Predicting hot corrosion rates under coal fired combined cycle power plant conditions." Thesis, Cranfield University, 1994. http://dspace.lib.cranfield.ac.uk/handle/1826/10512.
Full textAbstract:
Type 11 hot corrosion has been identified as a major life limiting factor of gas turbine
components in the topping cycle of coal fired combined cycle power plant. Impurities in the
coal combustion gases provide the environmental contaminants necessary for type 11 hot
corrosion to occur.
It is the purpose of the present study to develop corrosion lifting models such that
corrosion rates and thus component lives in coal fired combined cycle plant gas turbines may
be accurately predicted thus minimising efficiency losses and plant downtime due to
corrosion related problems.
Type 11 hot corrosion has been shown to follow bi11lodal distributions which cannot
be modelled using the well known mathematical models. It has been shown that a
probabilistic approach to modelling is appropriate and that the Gumbel Type I extreme value
model of maxima can be used to model the maximum extreme corrosion data This is
appropriate as it is the maximum extreme corrosion which in life limiting in the plant gas
turbine.
Basic corrosion data has been generated through a series of laboratory hot corrosion
tests designed to simulate the ambient conditions within the plant gas turbine. The variables
having most influence on the corrosion process have been identified as ; temperature, thermal
cycling, alkali (Na + K) metal sulphate deposition rate, S02 and HCl in the ambient
atmosphere.
The corrosion models have been developed from this data which accurately predict
the type 11 hot corrosion rates observed in the coal fired gas turbine of a combined cycle
power plant .
26
Ghashami, Bahman. "A New Power Storage, Cooling Storage, and Water Production Combined Cycle (PCWCC)." Thesis, Högskolan i Gävle, Energisystem, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-22725.
Full textAbstract:
Fresh water shortage and hot weather are common challenges in many countries of the world. In the other hand, the air conditioning systems which are used for indoor cooling cause peak electricity demand during high temperatures hours. This peak hour demand is very important since it is more expensive and mainly is supplied by fossil fuel power plants with lower efficiencies compare to base load fossil fuel or renewable owe plants. Moreover, these peak electricity load fossil fuel power plants cause higher green house gas emission and other environmental effects. So, all these show that any solution for these problems could make life better in those countries and all over the world.In this thesis, a new idea for a Power storage, Cooling storage, and Water production Combined Cycle (PCWCC) is introduced and reviewed. PCWCC is combination of two thermal cycles, Ice Thermal Energy Storage (ITES) and desalination by freezing cycle, which are merged together to make a total solution for fresh water shortage, required cooling, and high peak power demand. ITES is a well known technology for shifting the electricity demand of cooling systems from peak hours to off-peak hours and desalination by freezing is a less known desalination system which is based on the fact that the ice crystals are pure and by freezing raw water and melting resulted ice crystals, pure water will be produced. These two systems have some common processes and equations and this thesis shows that by combining them the resulted PCWCC could be more efficient than each of them. In this thesis, the thermodynamic equations and efficiencies of each PCWCC sub-systems are analyzed and the resulted data are used in finding thermodynamics of PCWCC itself. Also, by using reMIND software, which uses Cplex to find the best combinations of input/output and related processes, the cost of produced fresh water and cooling from PCWCC is compared with total cost of fresh water and cooling produced by each sub-systems of PCWCC in three sample cities all over the world, Kerman, Dubai, and Texas. These cities are chosen since they have similar ambient temperature trend with different electricity and fresh water tariff's. The results show that, the PCWCC is economical where there is a significant electricity price difference between ice charging and ice melting hours, off-peak and peak hours, of the day or when the fresh water price is high compare to electricity price. The results also show that how the revenue from fresh water could cover the used electricity cost and make some income as well.
27
Allen, Robert William. "The reciprocating joule cycle engine for micro combined heat and power applications." Thesis, University of Plymouth, 2008. http://hdl.handle.net/10026.1/2683.
Full textAbstract:
Micro CHP has been identified as a means of reducing the carbon dioxide emissions from household energy consumption. Large scale field trials undertaken in the UK, with systems internal to a single dwelling and based on Stirling engines, were disappointing because of the low thermal efficiencies of such engines. Alternative engines/devices with higher thermal efficiencies are currently being evaluated in Japan but such systems are external to the dwelling. The reciprocating Joule cycle engine is proposed as an engine for a micro CHP system because of its potential to be more thermally efficient than a Stirling engine and at least as thermally efficient as an internal combustion engine. Such an engine has not previously been analysed in detail nor is there any information that such an engine has been built and operated, particularly at power output levels below 5 kW. Mathematical modelling of the RJC engine is used to determine power outputs and efficiencies taking into account frictional, thermal and pressure losses. Such modelling indicated an engine with a maximum thermal efficiency of 33% making it suitable for micro CHP applications. When the individual models are combined to model a CHP system, and using the engine exhaust heat to preheat the combustion air, an overall maximum system efficiency of 79% was indicated.
28
Bouzguenda, Mounir. "Study of the combined cycle power plant as a generation expansion alternative." Thesis, Virginia Polytechnic Institute and State University, 1987. http://hdl.handle.net/10919/101165.
Full textAbstract:
Analysis of future alternatives for US utilities is needed as a part of evaluating the impact of combined cycle and phased-construction of integrated coal gasifier power plants on generation expansion. The study encompassed both large and small electric utilities and long-run, least-cost expansion plan for the generating system and studies of the short-run production cost of electrical generation for selected years. The long-run studies were carried out using the Wien Automatic System Planning Package (WASP-II). The optimal combined cycle penetration level was determined for a set of assumptions that involve economics, new technology trends, and feasibility as well as the utility's existing capacity and load forecast. Additional cases were run to account for phased construction and coal gasification. Two electric utilities were selected in this study. These are a U.S. southeastern utility the Bangladesh Electric Utility. The former was chosen as the large utility. The latter was considered a small size utility. WASP-II enhancements enabled us to run cases using IBM-RT and to account for phased construction. The sensitivity studies involved the penetration levels, the fuel supply (oil and natural gas), and economic dispatch of coal gasifiers in particular, and combined cycle power plants in general. Load forecast, and availability of hydroelectric energy were kept uniform. However, adding new power plants and retiring old ones were considered to achieve a more economical and reliable planning strategy while considering issues of technical feasibility.M.S.
29
Pavlaki, Maria. "Effects of combined stressors in the life-cycle trait of Daphnia Magna." Master's thesis, Universidade de Aveiro, 2009. http://hdl.handle.net/10773/8808.
Full textAbstract:
Mestrado em Toxicologia e EcotoxicologiaOs diversos compartimentos naturais estão constantemente expostos a vários tipos de contaminantes, bem como a misturas destes compostos, oriundos da actividade humana. Em ecossistemas aquáticos, vários stressores podem actuar em conjunto e causar danos aos organismos. O aumento do uso de pesticidas para fins agrícolas causa demanda a avaliação do risco inerente que estes compostos representam ao atingir o ambiente aquático. A lixiviação dos pesticidas está geralmente associada com o transporte de matéria orgânica e consequente diminuição da concentração de oxigénio em sistemas aquáticos. Os metais pesados podem ser introduzidos no ambiente através da actividade humana, como a actividade mineira. Portanto, a poluição dos ecossistemas é geralmente caracterizada por uma mistura de compostos químicos, que na maioria das vezes, estão presentes em combinação com stressores naturais Neste estudo, três tipos de stressores químicos, dois insecticidas (imidacloprid e thiacloprid), um metal pesado, níquel, e um tipo de stressor natural, representado por diferentes níveis de alimento foram testados com o objectivo de avaliar o impacto de cada stressor em isolado, bem como as suas misturas e combinações para um organismo não-alvo, Daphnia magna, através da aplicação do modelos teóricos Adição de concentração (AC) e Acção independente (AI), bem como seus possíveis desvios para sinergismo (causando efeito mais severo) ou antagonismo (efeito menos severo), dependentes da dose aplicada, ou dependência do rácio entre as doses aplicadas para cada item da mistura e/ou combinação. Os efeitos crónicos dos compostos isolados bem como os das misturas foram obtidos pela exposição de Daphnia magna a uma gama de concentrações por 21 dias. Os parâmetros analisados foram a produção de juvenis e o crescimento. Os resultados das exposições isoladas de Daphnia magna aos compostos químicos mostraram decréscimo na produção de juvenis e no crescimento do organismo. O mesmo padrão foi observado quando os organismos foram expostos a níveis baixos de alimento, enquanto a níveis elevados, a produção de juvenis e o crescimento foram estimulados. Os resultados da exposição à mistura de imidacloprid e thiacloprid mostraram um desvio do modelo AC, com uma dependência das doses aplicadas, sendo observado sinergismo a doses baixas e antagonismo a doses altas de ambos os compostos. Para a mistura de imidacloprid e níquel, nenhum desvio foi obtido, e a mistura foi ajustada ao modelo AI. A resposta na produção de juvenis para a combinação de imidaclopid ou níquel com níveis baixos de alimento não demonstrou desvio do modelo de acção independente. Para a análise da combinação entre imidacloprid ou níquel com níveis altos de alimento não foi possível aplicar os modelos teóricos, e os efeitos tóxicos dos químicos para os organismos foram avaliados para cada nível de alimento maior que o controlo. Neste estudo, é demonstrado que o impacto dos compostos químicos encontrados no ambiente, em misturas ou em combinação com stressores naturais será diferente do impacto induzido por estes compostos em isolado. O presente estudo mostra a necessidade da avaliação dos efeitos das exposições a misturas de químicos e combinações com stressores naturais encontrados no ambiente, e não somente a avaliação dos compostos em isolado.
The environment is being constantly exposed to various types of contaminants as well as their mixtures mainly due to human activities. In aquatic ecosystems several stressors may act together and affect the life traits of organisms. The increasing use of pesticides for agricultural purposes will require the assessment of the inherent risk when they arrive in marine or freshwater ecosystems. Pesticide runoffs are usually associated with high inputs of organic matter and depletion of oxygen in aquatic systems. Heavy metals can be introduced into the environment due to human activities such as mining processes. Therefore, polluted ecosystems are characterized by an amalgam of chemical compounds, most of the times in combination with natural stressors. In this study, three different chemical stressors, two neonicotinoid insecticides, imidacloprid and thiacloprid, a heavy metal, nickel and an environmental stressor, food level with low and high concentrations, were tested in order to assess the impact of their single toxic effects as well as their mixtures and combinations with a natural stressor on a non-target organism, Daphnia magna, with the use of theoretical models, Concentration Addition and Independent Action as well as possible deviations from them, like synergism, (causing a more severe effect) or antagonism (less severe effect), effects dependent from “dose level” (different deviations at high and low concentrations) or those dependent from “dose ratio” (deviations differ from mixture composition). Chronic effects of the single stressors as well as their combinations were assessed by exposing Daphnia magna to a range of concentrations for 21 days. The parameters analyzed were offspring production and body length of Daphnia magna. Results from single exposure of Daphnia magna to the chemical compounds showed a decrease in offspring production and in the body length of the organism. The same was observed when D. magna was exposed to low levels of food while in increased levels of food the offspring production and body length increased. Mixture exposure of imidacloprid and thiacloprid for offspring production showed a deviation from the CA model to dose level dependency indication synergism at low does level and antagonism at high does level of the chemicals. For the mixture of imidacloprid and nickel no deviation was obtained and the mixture fitted the IA model. Offspring production from the combinations of imidacloprid or nickel with low food levels showed no deviation from the IA model. For the combinations of imidacloprid or nickel with high food levels it was not possible to use the theoretical models and the toxic effects of the chemicals to the organism were assessed for each food level higher than the control. In this study, it is presented that the impact of chemicals found in the environment in mixtures between them or in combinations with environmental stressors will be different to the impact the single stressors induce. This study shows the need for evaluation of the exposure effects of mixtures of chemicals and combinations with natural stressors found on the environment and not only the single exposure effects.
30
Martin, Christopher L. "Study of cooling production with a combined power and cooling thermodynamic cycle." [Gainesville, Fla.] : University of Florida, 2004. http://purl.fcla.edu/fcla/etd/UFE0008332.
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Codeceira, Neto Alcides. "Assessment of novel power generation systems for the biomass industry." Thesis, Cranfield University, 1999. http://hdl.handle.net/1826/3448.
Full textAbstract:
The objective of this programme of research is to produce a method for
assessing and optimising the performance of advanced gas turbine power
plants for electricity generation within the Brazilian electric sector. With the
privatisation of the Brazilian electric sector, interest has been given to the
thermal plants and studies have been carried out along with the use of other
alternative fuels rather than fossil fuels.
Biomass is a fuel of increasing interest for power generation systems
since it is clean and renewable. Essentially all biomass power plants in the
Brazilian market today operate on a steam Rankine cycle, which has a poor
efficiency. The Brazilian electricity market has paid attention on Biomass
integrated gasification gas turbine (BIG/GT) combined cycle plants where
solid biomass is gasified. A simple chemical model for representing the
gasifier in the power plant is presented and optimisation of the gasification
process has been applied.
The method for assessing the performance of power plants takes into
account not only energy, but it applies the exergy method, which uses the
second law of thermodynamics and works out the destruction of energy inside
plant components and energy losses rejected to atmosphere. A
thermoeconomic model for assessing the power plant has also been
described.
The optimisation of the assessment method of power plants using
exergy and thermoeconomics has been proposed based on genetic
algorithms. This new technique has been fairly successful at solving
optimisation problems and is easy to implement. The decision of applying
genetic algorithms is due to the complexity of the mathematical model applied
in the performance assessment of power plants.
The assessment of combined cycles like gas / steam cycle, gas / air
cycle, gas / steam / freon cycle, gas / air / freon cycle and chemically
recuperated gas turbine have been investigated. The application of the overall
assessment method helps to understand different and very expensive choices
of power plants before making final decisions.
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Kandamby, Naminda Harisinghe. "Mathematical modelling of gasifier fuelled gas turbine combustors." Thesis, Imperial College London, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.267305.
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Gryczon, Michal. "Combined life cycle and economic assessment of wood based bio fuels in Norway." Thesis, Norwegian University of Science and Technology, Department of Energy and Process Engineering, 2008. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-8935.
Full textAbstract:
The increasing global demand for energy coupled with decreasing oil-supplies, and increasing risk of adverse climate change due to anthropogenic carbon emissions has created the need for combined economic and environmental assessment. This thesis attempt at devising such a framework based upon Life Cycle Assessment (LCA) and Life Cycle Costing (LCC). These methodologies represent two well established approaches for measuring environmental and economic performance of industrial projects and products. The LCA framework permits introduction of system expansion by interfacing with the greater economy by the hybrid-LCA. This approach also permits the assessment of life-cycle costs within the mathematical structure. The fundamental computations of LCA and LCC are introduced in this text in order to establish the combined assessment framework. This assessment method is applied to two National Renewable Energy Laboratory's studies on bio-ethanol production from lignocellulose. The studies are adapted to Norwegian economic conditions in order to assess the price and emissions of ethanol production from Norwegian wood mass. By combining these performance characteristics, a mitigation price of substituting gasoline with ethanol is established for various plant sizes as well as prices of gasoline.
34
Wilson, Jonathan David. "A hybrid SOFC-microturbine combined-cycle system: modeling, efficiency evaluation and power management." Thesis, Montana State University, 2012. http://etd.lib.montana.edu/etd/2012/wilson/WilsonJ0512.pdf.
Full textAbstract:
As centralized electricity generation and transmission issues continue to complicate electricity demand, interest in distributed generation solutions is increasing. Solid oxide fuel cells are high temperature and efficiency electrochemical devices that can operate on natural gas as well as hydrogen. When in combined cycle operation with a microturbine, the system has the ability to utilize the unused fuel from the solid oxide fuel cell and waste heat to increase the electrical energy, overall efficiency, and feasibility of market penetration of the system. The waste heat can also be repurposed outside the system, known as combined heat and power, for heating residential water supplies. This thesis presents the modeling, efficiency evaluation and power management of a hybrid solid oxide fuel cell/microturbine system in combined cycle operation with combined heat and power functionality for residential applications in islanded and grid-connected modes. The response of the system to load changes is also examined. The dynamic models of the solid oxide fuel cell and microturbine are integrated using power electronic interfacing and simulated in Matlab/Simulink. Simulation results demonstrate an efficiency increase of the system in combined cycle operation and the dynamic behavior of the system in stand-alone operation under different load conditions.
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Ozgirgin, Ekin. "Utilization Of Natural Gas, Optimization Of Cogeneration/ Combined Cycle Applications In Campus Environment." Master's thesis, METU, 2004. http://etd.lib.metu.edu.tr/upload/12604986/index.pdf.
Full textAbstract:
A computer program, called &ldquoCogeneration Design"
is developed using Visual Basic 6.0, for conceptually designing cogeneration power plants. Design is focused on power plants to be built in university campuses, where there is mainly heating, hot water, electricity and sometimes cooling demands. Middle East Technical University campus is considered as the primary working area. Before the conceptual design study, detailed information regarding description of the campus, infrastructure, annual electric, water and heat demand covering last 10 years, properties of existing heat plant including natural gas expenses and specifications of the steam distribution pipes and electricity grid are collected and examined in detail. Throughout the thesis, eight different natural gas fired cogeneration power plant designs are developed regarding different gas turbine and steam turbine configurations, for METU Campus, considering the Campus'
properties described above, by using the "
Cogeneration Design"
program. Then, by means of a thermoeconomic optimization process, cost summary reports are prepared and the feasibility of the designed cogeneration power plants are discussed.
36
Klymkiw, Orysia Zora. "The combined uses of life cycle and structural family therapy with remarried families." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/mq23366.pdf.
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Arvesen, Oystein, and Vegard Gjelsvik Medbø. "Valuation of a Combined Cycle Gas Turbine : under price uncertainty and operational constraints." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for industriell økonomi og teknologiledelse, 2012. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-21056.
Full textAbstract:
In this thesis we combine multivariate time series modelling with real options theory to value a combined cycle gas turbine. We propose a novel price model with co-integrated power, gas and carbon prices, with multivariate stochastic volatility and MNIG distributed errors. The estimated model is found to outperform competing specications in terms of higher likelihood and lower information criteria. We implement a Least Squares Monte Carlo (LSM) simulation to value the plant, incorporating ramp times, startup costs and variable plant eciency. We take into account that day-ahead prices are settled the day before prices take eect, which is often overlooked in related literature. We nd that ignoring this leads to suboptimal choices and a lower value estimate. An analysis of the regressions in the LSM algorithm reveals that the choice of basis functions has a signicant eect on the estimated value of the plant. Particularly, for a low-eciency plant, a regression on the spark spread underestimates the value by 20% compared to a regression on both the electricity price and the fuel cost components. This implies that in spread option valuations where the LSM is applicable, simulating all asset or commodity prices may be advantageous over simulating the spread alone.
38
Nourouzilavasani, Samira. "Technico-Economic Evaluation of Bitumen-Coke Integrated Gasification Combined Cycle with CO2 Capture." Thesis, Université Laval, 2008. http://www.theses.ulaval.ca/2008/25542/25542.pdf.
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Rachakonda, Anil. "Potentially available natural gas combined cycle capacity : opportunities for substantial CO₂ emissions reductions." Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/62774.
Full textAbstract:
Thesis (S.M. in Engineering and Management)--Massachusetts Institute of Technology, Engineering Systems Division, 2010.Cataloged from PDF version of thesis.
Includes bibliographical references.
This thesis analyzes the potential for existing natural gas combined cycle (NGCC) power generation to displace coal generation thereby reducing emissions of CO₂ and criteria pollutants regulated under the Clean Air Act. It also examines the potential for unused NGCC capacity to eliminate transmission congestion while simultaneously reducing CO₂ and other criteria pollutant emissions. The average capacity factor of the entire natural gas fleet in year 2008 was 26%. The average capacity factor of NGCC units, a subset of the gas fleet, is 41%. NGCC units, however, are designed to operate at capacity factors as high as 85%. The delta of these two numbers has generated significant policy interest as a means for reducing C02 emissions through some type of environmental dispatch that would favor NGCC over coal generation without the need for additional capital investment. The maximum potential of natural gas power generation to displace inefficient coal generation was determined. This upper limit can provide regulators and policy makers with guideposts for further review. Various operational constraints including transmission limitations were then modeled to determine the extent to which these constraints limit fuel switching opportunities. An analysis was conducted to estimate the effects of fuel switching on transmission congestion. The conclusion of this analysis was that generation from potentially available NGCC capacity located in regions with high load centers can help alleviate the transmission congestion problem with minimal or zero capital investment for building new generation capacity. Next, an hourly dispatch model was developed that incorporates many of the complexities of the power system. This model dispatches generation from various power plants under two scenarios: a carbon unconstrained scenario (base case); and a carbon constrained scenario. Under the carbon constrained scenario, dispatch preference is give to NGCC generation over coal generation. Two regions were modeled: the Electric Reliability Council of Texas (ERCOT), which is primarily Texas; and the Florida Reliability Coordinating Council (FRCC), which is primarily Florida. Results from the two cases indicate that, without compromising system reliability: In the ERCOT region, displacing some coal generation with existing and available NGCC generation would lower CO₂ emissions by nearly 22%, SO2 by 70% and NOx by 49%, compared to the base case. * In the FRCC region, displacing some coal generation with existing and available NGCC generation would lower CO₂ emissions by nearly 10%, 502 by 38% and NOx by 25%, compared to the base case. The model results also indicate that for both ERCOT and FRCC, these emissions savings can be achieved with a 10% increase in electricity prices. This translates into a cost of emissions reductions of $20/ton of CO₂ in ERCOT and $40/ton of CO₂ in FRCC. This compares to the cost of emissions reductions from corn ethanol, which is about $750/ton of CO₂, as reported by Congressional Budget Office'. Finally, a comparison was made between the results of the hourly dispatch model and the ReEDS model, a more complex model developed by Department of Energy's (DOE) National Renewable Energy Laboratory (NREL).
by Anil Rachakonda.
S.M.in Engineering and Management
40
Prakash, Kshitij. "Simulation and optimization of hot syngas separation processes in integrated gasification combined cycle." Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/55078.
Full textAbstract:
Thesis (S.M.)--Massachusetts Institute of Technology, Computation for Design and Optimization Program, 2009.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 131-137).
IGCC with CO2 capture offers an exciting approach for cleanly using abundant coal reserves of the world to generate electricity. The present state-of-the-art synthesis gas (syngas) cleanup technologies in IGCC involve cooling the syngas from gasifier to room temperature or lower for removing Sulfur, Carbon dioxide and Mercury, leading to a large efficiency loss. It is therefore important to develop processes that remove these impurities from syngas at an optimally high temperature in order to maximize the energy efficiency of an IGCC plant. The high temperature advanced syngas cleanup technologies are presently at various stages of development and it is still not clear which technology and configuration of IGCC process would be most energetically efficient. In this thesis, I present a framework to assess the suitability of various candidate syngas cleanup technologies by developing computational simulations of these processes which are used in conjunction with Aspen Plus® to design various IGCC flowsheet configurations. In particular, we evaluate the use of membranes and sorbents for CO2 separation and capture from hot syngas in IGCC, as a substitute to solutionbased absorption processes. We present a multi-stage model for CO2 separation from multi-component gas mixtures using polymeric membranes based on the solutiondiffusion transport mechanism. A numerical simulation of H2 separation from syngas using Pd-alloy based composite metallic membranes is implemented to assess their performance for CO2 sequestration.
(cont.) In addition, we develop an equilibrium-based combined pressure and temperature swing adsorption-desorption model to estimate the amount of energy required for capturing pollutants using regenerable sorbent beds. We use our models with Aspen Plus® simulations to identify optimum design and operating conditions for membrane and adsorption processes in an IGCC plant. Furthermore, we identify from our simulations desired thermodynamic properties of sorbents and material properties of membranes that are needed to make these technologies work successfully at IGCC conditions. This should serve to provide an appropriate direction and target for ongoing experimental efforts in developing these novel materials.
by Kshitij Prakash.
S.M.
41
Kretzschmar, Holger. "The Hybrid Pressurized Air Receiver (HPAR) for combined cycle solar thermal power plants." Thesis, Stellenbosch : Stellenbosch University, 2014. http://hdl.handle.net/10019.1/86377.
Full textAbstract:
Thesis (MScEng)--Stellenbosch University, 2014.ENGLISH ABSTRACT: Concentrating solar power technology is a modern power generation technology in which central receiver systems play a significant role. For this technology a field of heliostats is used to reflect solar irradiation to the receiver located on top of the tower. An extensive review has shown that contemporary receiver designs face geometric complexities, lack of thermal efficiency as well as issues with durability and cost. The purpose of this study is to develop a new receiver concept that can potentially reduce these issues. A parametric analysis was used to identify potential means of improvement based on an energy balance approach including sensitivities involved with convection and radiation heat transfer. Design criteria such as the use of headers to minimize pressure drop was also investigated. Based on these findings the hybrid pressurized air receiver was developed which is a combination of tubular and volumetric receiver technologies. The fundamental idea of the receiver was investigated by simulating the ray-tracing and coupled natural convection and radiation heat transfer. The ray-tracing results have shown that the use of quartz glass is a prospective solution to higher allowable flux densities, but with reflection losses in the order of 7 %. The coupled natural convection heat transfer simulation further revealed that the receiver concept effectively eliminates the escape of buoyant plumes and radiative heat losses are minimized. Empirical data was gathered from a medium flux concentrator and good agreement with the numerical results was obtained. The thesis therefore concludes that the research outcomes were met. Ongoing research aims to optimise the receiver concept for a 5MW pilot plant.
AFRIKAANSE OPSOMMING: Gekonsentreerde sonkrag tegnologie is ’n moderne kragopwekkingstegnologie waar sentrale ontvangersisteme ’n beduidende rol speel. Vir hierdie tegnologie word ’n veld heliostate gebruik om sonstraling na die ontvanger wat aan die bopunt van die toring geleë is te reflekteer. ’n Omvattende hersiening het daarop gewys dat kontemporêre ontwerpe van die ontvangers ’n aantal geometriese kompleksiteite, ’n tekort aan termiese doeltreffendheid sowel as probleme in terme van duursaamheid en koste in die gesig staar. Die doel van die studie is om ’n nuwe ontvangerskonsep te ontwikkel wat moontlik hierdie probleme kan verminder. ’n Parametriese analise is gebruik om potensiële maniere van verbetering aan te dui wat gebaseer is op ’n energiebalans benadering; insluitend sensitiwiteite betrokke by konvektiewe en stralingswarmteoordrag. Ontwerpkriteria soos die gebruik van spruitstukke om drukverliese te minimaliseer is ook ondersoek. Gebaseer op hierdie bevindinge is die hibriede saamgepersde-lug ontvanger ontwikkel. Laasgenoemde is ’n kombinasie van buis- en volumetriese ontvangertegnologie. Die fundamentele idee van die ontvanger is ondersoek deur straalberekening asook die gelyktydige natuurlike konveksie en stralingswarmteoordrag te simuleer. Die straalberekeningsresultate het getoon dat die gebruik van kwarts glas ’n moontlike oplossing is om hoër stralingsintensiteit te bereik, maar met refleksieverliese in die orde van 7 %. Die gelyktydige natuurlike konveksie en stralingswarmteoordrag simulasie het verder aan die lig gebring dat die ontvangerkonsep die ontsnapping
42
Parmar, J. "Turbine inlet temperature measurement for control and diagnosis in combined cycle gas turbine." Thesis, Cranfield University, 2002. http://dspace.lib.cranfield.ac.uk/handle/1826/11053.
Full textAbstract:
The author was responsible for the Guarantee verification, testing and
eventually Acceptance of all of National Power's Combined Cycle Gas
Turbines for its commercial operation. It was discovered during the early
Acceptance Testing of these power stations that the Original Equipment
Manufacturers (OEMs) used empirical and indirect
~-~;
methods to derive the gas
turbine inlet temperature. This had direct impact on the life of the gas turbine
components and revenue earned in terms of increase in maintenance costs
and loss in generating power. It became absolutely imperative that alternative
methods should be quickly deployed on National Power's gas turbines to
substantiate or otherwise the already used indirect methods of running the
gas turbines.
A completely novel method of using ceramic thermocouples probes and
embedded ceramics onto blades to monitor elevated gas temperatures from
the early trials on large coal fired boilers to specially made burner rigs and the
Spey gas turbine are discussed. A patent for the ceramic temperature probe
was filed and approved. Finally, a non-intrusive infra-red thermal pyrometry
was installed on two of National Power's CCGT power stations. The report
includes technical aspects on emissivity, radiation, risks, obstacles
encountered, and the methodology used to install the pyrometry.
Using the data collated from Deeside Power Station, where two pyrometers
are currently installed, the results obtained from the engine simulation are
validated. Once the model was validated and the data correlated with the
actual data obtained, it can be concluded that the deployment of pyrometry
can control the diagnostics and operational behaviour of the CCGT plant. The
efficiency of the gas turbine was shown to increase by about 0:4% and the
corresponding increase in power was 1.3%, which would make a substantial
savings in the operating and maintenance costs to National Power. This was
estimated to be in access of £25,OOO,OOOlannum.
43
Nourouzilavasani, Samira. "Technico-economic evaluation of bitumen-coke integrated gasification combined cycle with CO₂ capture." Master's thesis, Université Laval, 2008. http://www.theses.ulaval.ca/2008/25542/25542.pdf.
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Huang, Ye. "The behaviour of coal-fired pressurized fluidised bed combustion systems." Thesis, University of Ulster, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.284834.
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Курилов, Анатолій Федорович, Анатолий Федорович Курилов, Anatolii Fedorovych Kurylov, В. В. Колесник, and И. В. Воробьев. "Уменьшение влияния сопротивления газовоздушного тракта котла - утилизатора ПГУ - 20 на мощность газовой турбины." Thesis, Издательство СумГУ, 2007. http://essuir.sumdu.edu.ua/handle/123456789/19327.
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Yilmaz, Oguz. "Participation Of Combined Cycle Power Plants To Power System Frequency Control: Modeling And Application." Master's thesis, METU, 2006. http://etd.lib.metu.edu.tr/upload/12607228/index.pdf.
Full textAbstract:
This thesis proposes a method and develops a model for the participation of a combined cycle power plant to power system frequency control.
Through the period of integration to the UCTE system, (Union for Coordination of Transmission of Electricity in Europe) frequency behavior of Turkey&rsquos grid and studies related to its improvement had been a great concern, so is the reason that main subject of my thesis became as &ldquo
Power System Frequency Control&rdquo
. Apart from system-wide global control action (secondary control)
load control loops at power plants, reserve power and its provision even at the minimum capacity generation stage, (primary control) are the fundamental concerns of this subject. The adjustment of proper amount of reserve at the power plants, and correct system response to any kind of disturbance, in the overall, are measured by the quality of the frequency behaviour of the system. A simulator that will simulate a dynamic gas turbine and its control system model, together with a combined cycle power plant load controller is the outcome of this thesis.
47
Rieger, Mathias. "Advanced modeling and simulation of integrated gasification combined cycle power plants with CO2-capture." Doctoral thesis, Technische Universitaet Bergakademie Freiberg Universitaetsbibliothek "Georgius Agricola", 2014. http://nbn-resolving.de/urn:nbn:de:bsz:105-qucosa-150522.
Full textAbstract:
The objective of this thesis is to provide an extensive description of the correlations in some of the most crucial sub-processes for hard coal fired IGCC with carbon capture (CC-IGCC). For this purpose, process simulation models are developed for four industrial gasification processes, the CO-shift cycle, the acid gas removal unit, the sulfur recovery process, the gas turbine, the water-/steam cycle and the air separation unit (ASU). Process simulations clarify the influence of certain boundary conditions on plant operation, performance and economics. Based on that, a comparative benchmark of CC-IGCC concepts is conducted. Furthermore, the influence of integration between the gas turbine and the ASU is analyzed in detail. The generated findings are used to develop an advanced plant configuration with improved economics. Nevertheless, IGCC power plants with carbon capture are not found to be an economically efficient power generation technology at present day boundary conditions.
48
Watson, W. James. "Constructing success in the electric power industry : combined cycle gas turbines and fluidised beds." Thesis, University of Sussex, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.246252.
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Lin, TsungPo. "An adaptive modeling and simulation environment for combined-cycle data reconciliation and degradation estimation." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/24819.
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Thesis (Ph.D.)--Aerospace Engineering, Georgia Institute of Technology, 2008.Committee Chair: Dimitri Mavris; Committee Member: Erwing Calleros; Committee Member: Hongmei Chen; Committee Member: Mark Waters; Committee Member: Vitali Volovoi.
50
Goel, Nitin. "Theoretical and experimental analysis of absorption-condensation in a combined power and cooling cycle." [Gainesville, Fla.] : University of Florida, 2005. http://purl.fcla.edu/fcla/etd/UFE0012440.
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