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Effective Investment Planning in Waste-to-Energy Systems
Šomplák, Radovan ; Klemeš,, Jiří (referee) ; Žaloudík, Petr (referee) ; Stehlík, Petr (advisor)
PhD thesis deals with the application of the simulation and optimization methods in the waste-to-energy field. An introduction describes the current state of the waste management in the EU with the focus on the Czech Republic. In the following chapter the evaluation criteria for investment intentions and the basic principles of stochastic programming are discussed. The core of the work lays in the mathematical models for the planning and operation of the process plants as well as in the mathematical models for the waste collection. The transportation problem involves all considered technological elements and therefore it is possible to simulate the waste streams between the producers and processors. This approach is demonstrated with five case studies. In the first three studies the calculations for the potential investor are presented. The main outcome of these case studies is the determination of the level of attractiveness of investment and the identification the greatest risks. Another case study is devoted to an analysis with the focus on perspective of government policies and in the last case study the issue of the waste management is analyzed in detail from the perspective of the waste producers. Developed computational tools are flexible and can be further developed and adapted based on the objectives of the specific tasks.
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Simulation tool for gas microturbine integration into industrial operations
Konečná, Eva ; Stehlík, Petr (referee) ; Ovčačík,, Filip (referee) ; Máša, Vítězslav (advisor)
Current challenging energy situation gives rise to the need for highly efficient use of primary energy sources. Gas microturbines are a potential solution to this situation as they represent a progressive source of combined heat and power production. Gas turbines work with electric efficiency around 30 % and another 50 % is hidden in hot flue gas. Leveraging this waste heat is essential for achieving high overal efficiency of production and minimizing the use of primary energy. This thesis introduces a methodology for integration of gas microturbines into industrial operation. This methodology served as a basis for creating a software tool for selecting an optimal gas microturbine and seting up an efficient use of the waste heat from the produced flue gas, specifically direct drying, technological heating of process streams, preparation of warm utility water, and heat accumulation. It also includes technical-economic evaluation of the investment. The methodology is represented by an unique software tool which evaluates various alternatives of a gas microturbine integration into a mid-sized industrial laundry, and recommends the most favourable option. The tool was build using programming language Python in combination with MS Excel to offer great ease of use without a need for any specialized software. The biggest advantage, however, is its universality which allows adapting this software for other industrial processes. It is sufficient for the user to only have a standard operational knowledge of the target process. A laundry operation was selected for this case study, and data from several industrial laundries in Czech republic was collected. Its analysis revealed that the ratio of required electrical and heat energy is an important criterium when selecting a gas microturbine as the main power source. Specifically for older laundry operations, it is necessary to firstly undergo an energy optimization before selecting a suitable power source. If integrated correctly, it is possible to achieve overal efficiency of the gas microturbine of up to 90 % and an acceptable payback period of the investment. A suitable target process for integrating the gas microturbine is one that leverages the gas microturbine’s biggest advantage – production of hot and clean flue gas. It is necessary to look for those processes where a maximum of this flue gas can be used directly without a need for any other costly devices for heat transfer. Drying in laundries certainly represents such a process. The proposed software is an easy, quick, and most importantly universal tool for evaluating suitability of a gas microturbine based on common operational knowledge of the respective process.
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PERSPECTIVE METHODS OF SEWAGE SLUDGE UTILISATION FOR ENERGY PRODUCTION
Elsässer, Thomas ; Klemeš,, Jiří (referee) ; Žaloudík, Petr (referee) ; Stehlík, Petr (advisor)
Tato práce o energetickém využití čistírenských kalů obsahuje popis vlastností kalu (hustota, měrná tepelná kapacita a dynamická viskozita). Stěžejní kapitoly jsou věnovány desintegraci kalu pro zvýšení obsahu sušiny po odvodnění a experimentálnímu zkoumání tvorby emisí při spalování kalu, kde byl posuzován vliv přídavku alkálie. Spalování vysušeného kalu proběhlo ve fluidní vrstvě, byla zkoumána produkce škodlivin a distribuce těžkých kovů. Druhá ucelená část práce je věnována termochemické desintegraci stabilizovaného kalu, přičemž byl experimentálně vyhodnocován vliv na obsah vody v odvodněném kalu. Provedené experimenty sloužily k detekci vhodné teploty a dávky chemikálie. Výsledky experimentů byly rovněž podkladem pro ekonomickou bilanci, která je založena na úsporách za likvidaci menšího množství kalu.
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Equipment for Thickening Waste Water from Biogas Plants
Vondra, Marek ; Bébar, Ladislav (referee) ; Hoffman,, Pavel (referee) ; Stehlík, Petr (advisor)
This dissertation thesis deals with the development of technology which could tackle two major issues related to biogas plants. These issues concern the insufficient use of waste heat from biogas combustion and its subsequent processing. It also concerns the use of the fermentation residues which are formed in large quantities and whose use is restricted by law. Based on a literary search of separation methods, a vacuum evaporator was selected as the most suitable technology. Its advantages include its simple construction, operational reliability and robustness, low costs of thickening medium pre-treatment, potential for a quick commercial application and, especially, the chance to use a low-potential waste heat. A primary purpose of this technological unit is the reduction in the volume of fermentation residues. Other benefits include the efficient use of waste heat from a biogas plant, which would otherwise be wasted. Evaporators with a low consumption of electrical energy (which is a main product of a biogas plant) seem to be the best option for applications in the biogas plants. Three of these technologies were subjected to a more thorough analysis, which included the development of computational models and their quantification for conditions in a sample biogas plant. A one-stage evaporator with a forced circulation (680 – 712 kWhth/m3, 25.9 – 30.5 kWhel/m3) was evaluated as the least suitable option in terms of energy demands. The energy intensity of a three-stage evaporator with a falling film (241 – 319 kWhth/m3, 12.0 – 23.6 kWhel/m3) and a nine-stage flash evaporator (236 – 268 kWhth/m3, 13.6 – 18.4 kWhel/m3) is significantly lower. A multi-stage flash evaporator (MSF) was then chosen for development and will form the central focus of this thesis. The reasons for the choice are as follows: the low requirements on the heat transfer surface, good operational experience in the field of desalination, its simple construction, modularity and evaporation outside the heat transfer surface. A thorough technical-economic evaluation was also performed on the integration of the evaporator into the biogas plant. The main part of the work included the experimental development of a MSF evaporator prototype. The main objective of this development was to achieve a stable flow rate of the thickening liquid digestate fraction and the continuous formation of the distillate. This was not an easy objective to achieve, especially due to the properties of the liquid digestate, which has a non-newtonian characteristic and increased density and viscosity compared to water. The tendency of the liquid digestate to form foam was also the subject of analysis. The development of the evaporator and first successful operational test are described in the thesis in detail. This required the use of an anti-foaming product. A fully-developed prototype of the MSF evaporator allowed us to achieve continuous operation with a distillate production, reaching from 5 to 10 kg/h at a liquid digestate flow rate of 0.4–0.5 m3/h. The main drawback of this technology is the pollution of the distillate with ammonia nitrogen, and it is for this reason that the basic procedures of its subsequent elimination was selected for further analysis.
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Communication Strategy of Company
Stehlík, Petr ; MBA, Petr Adamus, (referee) ; Schüller, David (advisor)
This thesis deals with the design of communication strategy for Brno pharmacy U lazní. The task is to assess the current status and on the results of the analysis suggest appropriate measures in order to improve and streamline communication mix of the company. A part of this thesis is the evaluation of information with application of fuzzy logic.
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Analysis of Interactions in Waste Management
Szásziová, Lenka ; Hájek, Jiří (referee) ; Hrabec,, Dušan (referee) ; Stehlík, Petr (advisor)
PhD thesis deals with the application of simulation, forecasting and optimization methods in the waste management. An introduction describes current state and outlook in the waste management in the Czech Republic. The following chapter analyzes the available data base in the field of the waste management in the Czech Republic, focusing on the specifics and problems such as variable availability of spatially and hierarchically structured, heterogeneous input data. The core work is the computational tool named Justine, which represents the balance system, ensuring consistency of values for the standalone and aggregated data, in terms of their composition and distribution in intended area and time. Development of the tool was motivated by the need to predict the production and composition of various types of waste. The application of the concept is shown in three case studies, focusing on the prognosis of hazardous waste, the forecast of production and composition of municipal solid waste and components of separated waste collection, and estimation of the waste with waste-to-energy potential, all in the Czech Republic. The outputs of the tool represent valuable inputs for the related optimization supply chain models, which are used e.g. for the design of new waste-to-energy facilities.
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Modelling as Efficient Tool in Industrial Practice and Economic Aspects
Šarlej, Marek ; Klemeš,, Jiří (referee) ; Žaloudík, Petr (referee) ; Stehlík, Petr (advisor)
This doctoral thesis focuses on modelling as an efficient tool in industrial practice in the field of power industry and environmental engineering. It represents the modelling for technical as well as for economic part and their combination. Industrial companies do not evaluate only technical solutions in terms of investment costs, however, they search for optimized technical-economic solutions. The doctoral thesis describes the modelling of individual equipment as well as technological units in various levels of complexity. Case studies utilising various levels of modelling are represented herein.
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Energy Intensity Reduction of a Professional Laundry Care Process
Bobák, Petr ; Klemeš,, Jiří (referee) ; Noskievič, Pavel (referee) ; Stehlík, Petr (advisor)
Doctoral thesis deals with professional laundry care process and reduction of energy intensity and use of other operational commodities used in the process. Professional laundry care process is a specific energy intensive process; its purpose is to re-establish original properties of the now dirty laundry so that it may fulfil its functions again. This is basically a recycling and regeneration process comprising many sub-operations. Key operation is washing of the laundry in a washing bath, which removes impurities from the laundry. This thesis describes the most common technology of impurities removal, which is washing in a hot washing bath in cooperation with mechanical work and detergents. However, all of the described procedures may also be applied on alternative technologies, such as ozone washing, washing with low-temperature enzymes and ultrasound. Water is applied in all these technologies as a soaking agent. Water must have appropriate properties and must be removed from the laundry after the washing process in subsequent operations (drying, ironing, and pressing). Theoretical introduction of the thesis describes professional laundry care process in detail, and continues with mathematical modelling of the process and its main sub-operations (washing, drying) using mass and heat balance, and data acquisition and their application in research and development. Thesis further describes design of information system on the basis of relational database controlled by web application. This system enables to organize data and information from various sources – measured experimental data, data concerning measurement devices, operational records of machines, etc. Thesis further proposes how to evaluate and reduce energy intensity of a process. Descriptions are validated by examples and case studies. Key section of the thesis is a chapter describing experimental infrastructure. This infrastructure integrates several instalments of laundry equipment and is a fully functional operation of industrial laundry facility with 500kg/shift capacity, which serves as a model of energy intensive process. Sophisticated infrastructure and data acquisition system allows measuring wide spectrum of physical entities and examining factors influencing energy intensity of processes, and relationships between these factors as well as effectiveness of various savings measures in real life facilities.
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