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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

Geographic Information System (GIS) Simulation of Emergency Power Production from Disaster Debris in a Combined Heat and Power (CHP) System

Ryals, Christopher Shannon 30 April 2011 (has links)
The objective of this study is to determine a predicted energy capacity of disaster debris for the production of emergency power using a combined heat and power (CHP) unit. A prediction simulation using geographic information systems (GIS) will use data from past storms to calculate an estimated amount of debris along with an estimated energy potential of said debris. Rather than the expense and burden of transporting woody debris such as downed trees and wood framing materials offsite, they can be processed (sorting and chipping) to provide an onsite energy source to provide power to emergency management facilities such as shelters in schools and hospitals. A CHP unit can simultaneously produce heat, cooling effects and electrical power using various biomass sources.This study surveys the quantity and composition of debris produced for a given classification of disaster and location. A comparison of power efficiency estimates for various disasters is conducted.
42

Techno-economic analysis of a waste-to-energy system using innovative pyrolysis process

Perrens, Hannah Sofie January 2023 (has links)
Waste management is of growing concern with increasing amount of municipal waste generation and the industry standards are becoming stricter due to climate goals and sustainable development. Waste-to-energy (WTE) systems in the form of waste incineration have been promoted as a low-carbon energy source, but nevertheless have high greenhouse gas (GHG) emissions. Pyrolysis offers an alternative way of utilizing energy which at high temperatures and in the absence of oxygen thermally decomposes material and yields products such as synthetic gas and biochar. Bodø Storstue, a development project for a new sports arena in Northern Norway, has high ambitions for sustainable development. WTE by pyrolysis has been identified as a potential step toward reducing GHG emissions. Thus, this thesis looked into the technical and economic aspects of integrating pyrolysis as a decentralized WTE system. A simulation model was built in Aspen Plus, which shows the energy and mass balance through the different modules in the system. An economic analysis was performed using MS Excel which included the levelized cost of electricity and net present value calculation. The results suggest that the electricity demand in Bodø Storstue can be met by using pyrolysis for power generation, and that carbon can be stored in biochar which reduces the emissions compared to traditional waste incineration. Future studies should include a simulation model based on tested feedstock composition which would make the simulation more representative of true conditions. The price of biochar should also be included in the economic analysis to obtain more precise conclusions about the economic conditions that impact investment decisions. / Avfallshanteringen skapar en växande oro världen över med ökande avfallsmängder och strängare bestämmelser för industrianpassning till nya klimatmål och nya strategier för hållbar utveckling. Energiutvinningssystem ur avfall i form av direkt avfallsförbränning, s.k. waste-to-energy (WTE), har marknadsförts som en miljövänlig energikälla men låga utsläpp, men har trots detta en viss del fossilbaserad kolinnehåll samt höga helhetsutsläpp av växthusgaser. Pyrolysprocesser erbjuder ett alternativt sätt att utnyttja energi genom att termiskt bryta kolväten vid höga temperaturer och i frånvaro av syre ner till enklare molekyler och således generera gasformiga produkter samt biokol. Bodø Storstue är ett utvecklingsprojekt för att bygga en ny multifunktionell idrottsarena i norra Norge, med höga ambitioner för integrerat miljötänkande. WTE genom pyrolys har identifierats som en lovande åtgärd för att minska växthusgasutsläppen från arenan. Målet härmed är således att undersöka de tekniska och ekonomiska förutsättningarna for att integrera en nyutvecklad pyrolysprocess för arenan i form av ett decentraliserat kraftvärmeverk med lokal avfallshantering där också en del biokol utvinns i fast form för att potentiellt lagras som ren kol eller för att användas till jordförbättring. Simuleringsmodeller för kraftvärmesystemet byggdes i AspenPlusTM baserade på avfallspyrolys och syntesgasförbränning, som beräknar energi- och massbalanser genom olika delmoduler. I ett nästa skede utfördes förenklade ekonomiska analyser med andra verktyg för att sammanfatta elkostnader och nettonuvärdeuträkning. Resultaten tyder på att elbehovet i Bodø Storstue kan tillgodoses genom att använda avfallspyrolys för kraft- och värmegenerering, och att kol kan lagras i form av biokol vilket minskar utsläppen jämfört med traditionell avfallsförbränning. Framtida studier bör inkludera en simuleringsmodell baserad på testad och verklighetstrogen avfallssammansättning, vilket skulle göra simuleringen mer representativ för verkliga förhållanden på arenan. Värdet på biokol bör också inkluderas i den ekonomiska analysen för att få mer precisa slutsatser om de ekonomiska förutsättningarna.
43

Development of a Bayesian network model for assessing the resilience of biomass-based combined heat and power system

Alzahrani, Omar 30 April 2021 (has links) (PDF)
Due to the growing number of diverse power systems disruptions, including extreme weather events, technical factors, and human factors, assessing and quantifying the resilience of electric power subsystems has become an indispensable step to develop an efficient strategic plan to enhance the resilience and reliability of these systems and to endure the diverse interruptions. In this study, factors and sub-factors that may have either direct or indirect impact on the resilience of biomass-based combined heat and power systems are identified, and the interdependencies among them are determined as well. A Bayesian network model is implemented to quantify the resilience of a bCHP system, and the results are analyzed by applying three different techniques, which are sensitivity analysis, forward propagation analysis, and backward propagation analysis.
44

Optimisation algorithmique et modèles aléatoires d'un système électrique de cogénération : application au système électrique au Liban / Algorithmic optimization and random models of a cogeneration system : application to the libanese electric system.

Al asmar, Joseph 16 September 2015 (has links)
Les systèmes de cogénération (SC) sont largement définis par la production simultanée ou coïncidente de la production combinée de chaleur et d'électricité. L’idée de la cogénération revêt une importance particulière puisqu’elle est un outil de réduction des émissions à effet de serre. Comme les systèmes électriques ont été développés selon les carburants et leur utilisation énergétique, de même, les SC ont été développés afin d'utiliser l'énergie possible du carburant pour produire de l’électricité et de la chaleur. La décentralisation de la production électrique est désormais un événement existant. La favorisation maximale de l’électricité d’origine renouvelable ou des systèmes de
cogénération, a abouti à cette décentralisation formant une partie de la production électrique.
Cette thèse est appliquée au cas du système électrique libanais. Elle sert à évaluer la puissance optimale de cogénération qui doit être installée par le secteur public ou le secteur privé, ainsi que la mise en évidence des impacts économiques et environnementaux dus à l’intégration des SC et des énergies renouvelables dans le réseau. Dans ce travail de thèse, nous nous sommes intéressés à l’intégration des systèmes de cogénération dans un réseau électrique. Nous avons travaillé sur deux thèmes principaux et les avons appliqués au cas du réseau électrique libanais. Le premier thème principal est l’innovation d’une stratégie de prise de décision qui sert à trouver une puissance de cogénération respectant l’économie et l’environnement. Le second thème principal est l’optimisation et le contrôle du réseau électrique en fonction des énergies renouvelables (ER) et des SC intégrés. Les deux thèmes cités sont ensuite appliqués au cas du réseau électrique libanais pour montrer les avantages de l’intégration des SC et des ER dans ce réseau. / Cogeneration systems (CS) are largely defined by the simultaneous or coincident production of combined heat and power. The idea of cogeneration is of particular importance since it is a tool for reducing greenhouse gases emissions. As electrical systems have been developed according to the fuel and energy use, the CS have been developed to profit from the possible potential of the fuel energy to produce electricity and heat. Decentralization of power generation is considered an important fact. The maximum use of electricity from renewable sources or cogeneration systems, has leaded to the decentralization of power generation.This thesis is applied to the Lebanese electrical system. It is used to assess the optimum cogeneration power to be installed by the public sector or the private sector, as well as highlighting the economic and environmental impacts due to the integration of the CS and renewables into the grid. In this thesis, we focused on the integration of cogeneration systems into a grid. We worked on two major themes and have applied them to the case of the Lebanese electrical grid. The first main theme is the innovation of a new decision making strategy to find the cogeneration power respecting the economy and the environment. The second main theme is the optimization and the control of the electrical grid due to the integration of renewable energy (RE) and CS. The two themes cited are then applied to the case of the Lebanese electrical grid to show the benefits of the integration of RE and CS into this grid.
45

Framtida gasanvändning på Kalmar reningsverk : En ekonomisk jämförelse av olika investeringsmöjligheter

Halvorsen, Erik, Axelsson, Erik January 2017 (has links)
Då det finns planer på att ersätta det befintliga reningsverket i Kalmar inom en överskådlig framtid och nya krav om nödförsörjning av el har kommit från MSB, undersöktes möjligheten att använda den biogas som skulle komma att produceras på det nya reningsverket inom den egna verksamheten, istället för att som i dagsläget säljas. I denna studie undersöktes lönsamheten i att antigen investera i en biogasdriven generator som i normalfall ger en besparing i el och fjärrvärme och kan leverera reservkraft vid spänningsbortfall på nätet, eller försäljning av biogasen och inköp av ett dieseldrivet reservkraftverk.  Kostnadsförslag för biogasdrivna generatorer och reservkraftverk togs in. I denna ingick även service och komponenter för att kunna använda biogasen som bränsle. Utav kostnadsförslagen gjordes en LCC. Besparing av el och fjärrvärme samt förtjänst av försäljning av biogasen ställdes i relation mot varandra. Arbetet konkluderar att, baserat på de uträkningar som gjordes, en ottomotor är det mest lönsamma för att generera el och värme för internt bruk. / Because of the plans to replace the old sewage treatment plant in Kalmar, which has come to the end of its life cycle, and due to new requirements of emergency supply from SCCA (Swedish Civil Contingencies Agency), the possibility of using the biogas on the plant itself was evaluated. In this study, the profitability of two alternatives was evaluated. To invest in a biogas powered generator to produce electric power and heat, which would create savings in purchased electricity and district heating and work as an emergency generator, or to continue selling the biogas and invest in a diesel-powered emergency generator. Cost estimates of biogas powered generators and the equipment needed for using the biogas as fuel was required from dealers and manufacturers. The cost estimates were then compiled in a LCC. The calculated savings and the income from selling the biogas was then added to the LCC, the alternatives was then compared to each other. The study concludes that the most profitable alternative, based on the calculations, is to invest in a biogas powered generator and use the electricity and waste heat on the sewage plant.
46

Techno-economic studies of environmentally friendly Brayton cycles in the petrochemical industry

Nkoi, Barinyima January 2014 (has links)
Brayton cycles are open gas turbine cycles extensively used in aviation and industrial applications because of their advantageous volume and weight characteristics. With the bulk of waste exhaust heat and engine emissions associated, there is need to be mindful of environmentally-friendliness of these engine cycles, not compromising good technical performance, and economic viability. This research considers assessment of power plants in helicopters, and aeroderivative industrial gas turbines combined-heat-and-power (ADIGT-CHP) in the petrochemical industry. Thus, it consists of two parts: part A focuses on performance analysis of helicopter gas turbines, while part B entails technoeconomic and environmental risk assessment of ADIGT-CHP in the petrochemical industry. The investigation encompasses comparative assessment of simple cycle (SC) and advanced gas turbine cycle options including the component behaviours and the environmental and economic analysis of the systems. The advanced cycles considered include: recuperated (RC), intercooled (IC), intercooled-recuperated (ICR), and low pressure compressor zero-staged (LPC-ZS), cycles. The helicopter engines are analysed and subsequently converted to small-scale ADIGT engines. Also, modelling combined-heat-and-power (CHP) performances of small-scale (SS), and large-scale (LS) ADIGT engines is implemented. More importantly, a large part of the research is devoted to developing a techno-economic model for assessing, predicting, and comparing viability of simple and advanced cycle ADIGT-CHP in the petrochemical industry in terms of net present value (NPV), internal rate of return (IRR), and simple payback period (SPBP). The techno-economic performances of the ADIGT-CHP cycles are measured against the conventional case of grid power plus on-site boiler. Besides, risk and sensitivity of NPV with respect to uncertain changes in grid electricity cost, gas fuel cost, emission cost, and electricity export tariff, are investigated. Two case studies underlie the development of the techno-economic model. One case study demonstrates the application of the model for large-scale (LS) ADIGT-CHP, and the other for small-scale (SS) ADIGT-CHP, all in the petrochemical industry. By so doing, techno-economic and environmental risk analysis framework (a multi-disciplinary preliminary design assessment tool comprising performance, emissions, economic, and risk modules) is adapted to ADIGT-CHP in the petrochemical industry, which is the aim of this research. The investigation and results led to the conclusions that advanced cycle helicopter and ADIGT engines exhibit higher thermal efficiencies than simple cycle, and that savings exist in operational costs of ADIGT-CHP above the conventional case. Thus, for both SS ADIGT-CHP, and LS ADIGT-CHP cases, all ADIGT-CHP cycles are profitable than the conventional case. For LS ADIGT- CHP category, the IC ADIGT-CHP is the most profitable, whereas for SS ADIGT-CHP category, the RC ADIGT-CHP is the most profitable. The contribution to knowledge of this research is the development of a technoeconomic model for assessing, predicting, and comparing viability of simple and advanced cycle ADIGT-CHP in the petrochemical industry in terms of NPV, SPBP, and IRR over the conventional case of grid power plus on-site boiler. A second contribution is the derivation of simple and advanced cycle small-scale ADIGT and ADIGT-CHP from helicopter engines. Cont/D.
47

Using CHP plant to regulate wind power

Elzubair, Arwa January 2019 (has links)
Sweden is working on increasing the share of wind energy, but it comes along with many challenges,one of those challenges is the uncertainty of the wind power; CHP could be an option for betterutilizing of wind power by adapting the power to heat ratio according to wind energy fluctuation.The potential for utilizing installed wind energy in Sweden using CHP plant has been studied. A CHPplant installed in the South of Sweden was considered as studied case. To match the heat andelectricity demand requested by the region with the output from the CHP plant two scenarios weresimulated. Results showed that 5.3 MW of installed wind energy in Sweden could be adjusted andset to a level of 73.6 MW if the CHP plant alone were to cover the heat demand, and 25.4 MW ofinstalled wind power in Sweden could be adjusted and set to a level of 54.2 MW with an additionalheat supply of 8 MW in the studied case.
48

Retrofitting CHP Plant and Optimization of Regional Energy System

Han, Song January 2011 (has links)
The use of biomass-based combined heat and power (CHP) plants is considered by the EU administration to be an effective way to increase the use of renewables in the energy system, to reduce greenhouse gas emissions and to alleviate the dependency on imported fossil fuels. At present in Sweden, most of the CHP plants are operated in part-load mode because of variations in heat demand. Further use of the potential heat capacity from CHP plants is an opportunity for integration with other heat-demanding processes. Retrofitting the conventional CHP plants by integration with bioethanol and pellet production processes is considered a feasible and efficient way to improve the plants’ performances.   Modeling and simulation of the CHP plant integrated with feedstock upgrading, bioethanol production and pellet production is performed to analyze the technical and economic feasibility. When integrating with bioethanol production, the exhaust flue gas from the CHP plant is used to dry the hydrolysis solid residues (HSR) instead of direct condensation in the flue gas condenser (FGC). This drying process not only increases the overall energy efficiency (OEE) of the CHP plant but also increases the power output relative to the system using only a FGC. Furthermore, if steam is extracted from the turbine of the CHP plant and if it is used to dry the HSR together with the exhaust flue gas, pellets can be produced and the bioethanol production costs can be reduced by 30% compared with ethanol cogeneration plants.   Three optional pellet production processes integrated with an existing biomass-based CHP plant using different raw materials are studied to determine their annual performance. The option of pellet production integrated with the existing CHP plant using exhaust flue gas and superheated steam for drying allows for a low specific pellet production cost, short payback time and significant CO2 reduction. A common advantage of the three options is a dramatic increase in the total annual power production and a significant CO2 reduction, in spite of a decrease in power efficiency.   The retrofitted biomass-based CHP plants play a crucial role in the present and future regional energy system. The total costs are minimized for the studied energy system by using wastes as energy sources. Analyses of scenarios for the coming decades are performed to describe how to achieve a regional fossil fuel-free energy system. It is possible to achieve the target by upgrading and retrofitting the present energy plants and constructing new ones. The conditions and obstacles have also been presented and discussed through optimizing the locations for proposed new energy plants and planting energy crops. / REMOWE, CSC
49

Lignocellulosic Ethanol Production Potential and Regional Transportation Fuel Demand

Daianova, Lilia January 2011 (has links)
Road traffic dominates in domestic Swedish transportation and is highly dependent on fossil fuels, petrol and diesel. Currently, the use of renewable fuels in transportation accounts for less than 6% of the total energy use in transport. The demand for bioethanol to fuel transportation is growing and cannot be met through current domestic production alone. Lignocellulosic ethanol derived from agricultural crop residues may be a feasible alternative source of ethanol for securing a consistent regional fuel supply in Swedish climatic conditions.  This licentiate thesis focuses on regional transport fuel supply by considering local small-scale ethanol production from straw. It presents the results of investigations of regional transport fuel supply with respect to minimising regional CO2 emissions, cost estimates for transport fuel supply, and the availability of lignocellulosic resources for small-scale ethanol production. Regional transport fuel demand between the present and 2020 is also estimated. The results presented here show that significant bioethanol can be produced from the straw and Salix available in the studied regions and that this is sufficient to meet the regions’ current ethanol fuel demand.  A cost optimisation model for regional transport fuel supply is developed and applied for two cases in one study region, one when the ethanol production plant is integrated with an existing CHP plant (polygeneration), and one with a standalone ethanol production plant. The results of the optimisation model show that in both cases the changes in ethanol production costs have the biggest influence on the cost of supplying the regional passenger car fleet with transport fuel, followed by the petrol price and straw production costs.  By integrating the ethanol production process with a CHP plant, the costs of supplying regional passenger car fleet with transport fuel can be reduced by up to a third. Moreover, replacing petrol fuel with ethanol can cut regional CO2 emissions from transportation by half.
50

Techno-economic studies of environmentally friendly Brayton cycles in the petrochemical industry

Nkoi, Barinyima 10 1900 (has links)
Brayton cycles are open gas turbine cycles extensively used in aviation and industrial applications because of their advantageous volume and weight characteristics. With the bulk of waste exhaust heat and engine emissions associated, there is need to be mindful of environmentally-friendliness of these engine cycles, not compromising good technical performance, and economic viability. This research considers assessment of power plants in helicopters, and aeroderivative industrial gas turbines combined-heat-and-power (ADIGT-CHP) in the petrochemical industry. Thus, it consists of two parts: part A focuses on performance analysis of helicopter gas turbines, while part B entails technoeconomic and environmental risk assessment of ADIGT-CHP in the petrochemical industry. The investigation encompasses comparative assessment of simple cycle (SC) and advanced gas turbine cycle options including the component behaviours and the environmental and economic analysis of the systems. The advanced cycles considered include: recuperated (RC), intercooled (IC), intercooled-recuperated (ICR), and low pressure compressor zero-staged (LPC-ZS), cycles. The helicopter engines are analysed and subsequently converted to small-scale ADIGT engines. Also, modelling combined-heat-and-power (CHP) performances of small-scale (SS), and large-scale (LS) ADIGT engines is implemented. More importantly, a large part of the research is devoted to developing a techno-economic model for assessing, predicting, and comparing viability of simple and advanced cycle ADIGT-CHP in the petrochemical industry in terms of net present value (NPV), internal rate of return (IRR), and simple payback period (SPBP). The techno-economic performances of the ADIGT-CHP cycles are measured against the conventional case of grid power plus on-site boiler. Besides, risk and sensitivity of NPV with respect to uncertain changes in grid electricity cost, gas fuel cost, emission cost, and electricity export tariff, are investigated. Two case studies underlie the development of the techno-economic model. One case study demonstrates the application of the model for large-scale (LS) ADIGT-CHP, and the other for small-scale (SS) ADIGT-CHP, all in the petrochemical industry. By so doing, techno-economic and environmental risk analysis framework (a multi-disciplinary preliminary design assessment tool comprising performance, emissions, economic, and risk modules) is adapted to ADIGT-CHP in the petrochemical industry, which is the aim of this research. The investigation and results led to the conclusions that advanced cycle helicopter and ADIGT engines exhibit higher thermal efficiencies than simple cycle, and that savings exist in operational costs of ADIGT-CHP above the conventional case. Thus, for both SS ADIGT-CHP, and LS ADIGT-CHP cases, all ADIGT-CHP cycles are profitable than the conventional case. For LS ADIGT- CHP category, the IC ADIGT-CHP is the most profitable, whereas for SS ADIGT-CHP category, the RC ADIGT-CHP is the most profitable. The contribution to knowledge of this research is the development of a technoeconomic model for assessing, predicting, and comparing viability of simple and advanced cycle ADIGT-CHP in the petrochemical industry in terms of NPV, SPBP, and IRR over the conventional case of grid power plus on-site boiler. A second contribution is the derivation of simple and advanced cycle small-scale ADIGT and ADIGT-CHP from helicopter engines. Cont/D.

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