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Utilization of pyrolysis for liquid fuels production
Hruška, Daniel ; Bělohradský, Petr (referee) ; Hudák, Igor (advisor)
The main content of this bachelor thesis is description of matters of the pyrolysis units. Whereas there is an emphasize on basic description of the function, methods and the chemical processes during pyrolysis reaction in the pyrolysis unit for waste tratment a biomass, comparisons of the advantages and disadvantages selected types of the pyrolysis unit and analyzing of the product gaining during pyrolysis. Thesis also present qualitative comparison of the pyrolysis products and the commonly used fuels. The last part of the thesis is bestowed to a simplyficated mathematical and chemical calculation for energetic efficiency of pyrolysis products and comonly used fuels.
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Air enrichment with highly pure oxygen in combustion processes
Polášek, Kryštof ; Hudák, Igor (referee) ; Bělohradský, Petr (advisor)
This bachelor thesis deals with the oxygen enhanced combustion (OEC). The thesis describes different methods of enriching the combustion process with oxygen, also the advantages and disadvantages of enhancing the combustion are evaluated. The next part contains an overview of the use of OEC in specific industries. Since certain safety precautions must be taken when handling of oxygen, a separate chapter deals with the safety of oxygen enhanced combustion. In the last part of the thesis a simulation of the OEC process in ChemCAD software was carried out. The influence of oxygen concentration in the oxidizing agent on the flue gas volume, temperature, density and viscosity and the concentration of CO2 and H2O in the flue gas was investigated.
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The influence of atomizing media on the quality of the combustion of liquid fuels
Bojanovský, Jiří ; Skryja, Pavel (referee) ; Bělohradský, Petr (advisor)
The aim of the present work was to experimentally investigate the influence of atomizing medium on combustion properties of methyl-ester of rapeseed oil. The experiments were carried out in a water-cooled horizontal combustion chamber. The pneumatic atomization using effervescent atomizer was used in test. As atomizing medium compressed air and superheated steam was chosen. The tests were performed at GLR = 15, 20 and 25 %. The experiments were focused on the investigation of the flame characteristics, quality of combustion, emissions, temperature of flue gas, distribution of heat fluxes and stability of combustion. Results revealed that atomization by compressed air is more efficient (approximately by 6 %), on the other hand it leads to higher NO emissions (for 15 mg/mN3 due to higher in-flame temperature).
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Methods for the reduction of nitrogen oxides
Šimeček, Radek ; Hudák, Igor (referee) ; Bělohradský, Petr (advisor)
This Bachelor’s thesis deals with methods for the reduction of nitrogen oxides during industrial combustion. In the chapter relating to legislation are summed up the limits for stationary sources of pollution valid in the Czech Republic, further are stated the legislative tools for reducing and monitoring emissions. The next part contains an overview of primary and secondary methods for reducing NOx emissions, including pros and cons of the methods. Finally, a simulation in software ChemCAD is carried out, demonstrating the influence of combustion air temperature and flue gas recirculation on parameters of combustion.
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The influence of atomizing media on the quality of the combustion of liquid fuels
Bojanovský, Jiří ; Skryja, Pavel (referee) ; Bělohradský, Petr (advisor)
The aim of the present work was to experimentally investigate the influence of atomizing medium on combustion properties of methyl-ester of rapeseed oil. The experiments were carried out in a water-cooled horizontal combustion chamber. The pneumatic atomization using effervescent atomizer was used in test. As atomizing medium compressed air and superheated steam was chosen. The tests were performed at GLR = 15, 20 and 25 %. The experiments were focused on the investigation of the flame characteristics, quality of combustion, emissions, temperature of flue gas, distribution of heat fluxes and stability of combustion. Results revealed that atomization by compressed air is more efficient (approximately by 6 %), on the other hand it leads to higher NO emissions (for 13 mg/mN3 due to higher in-flame temperature).
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Design of optimal mixing of large-scale digesters
Bradáč, Antonín ; Bělohradský, Petr (referee) ; Zejda, Vojtěch (advisor)
The aim of this diploma thesis is an optimal method of mixing of the digester with consideration to the uniform mixing of the whole volume, ensuring the quality process conditions for the anaerobic fermentation and the maximum yield and quality of the produced biogas. First chapters describe the basic design parameters, general calculations and the principles for design of individual types of mixers, supplemented by practical examples of mixing large capacity tanks. The work introduces the problem of sludge formation at the sewage treatment plant with an emphasis on sludge treatment and the processes which take place inside the fermenter. Various types of design of anaerobic sludge stabilization digester were introduced. Also ways of their operation, which are necessary for the quality of the fermentation, were presented. In the next chapters, various ways of mixing high-capacity digester tanks and experience from the operation of selected treatment plants were described. According to the theoretical research part of this thesis, several types of mixing equipment was designed for the experimental digestion tank built at the Institute of Process Engineering which is used for research work with mixers. Measurement of the selected pneumatic mixing method was performed on the experimental tank and the findings were evaluated.
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Characteristic parameters of fuel nozzles
Ledererová, Lucie ; Zejda, Vojtěch (referee) ; Bělohradský, Petr (advisor)
Many industrial applications acquire necessary thermal energy through the combustion process. The basic element of each combustion appliance is a burner and one~part~of~it~is a~nozzle system that supplies fuel to a combustion chamber. The geometry of the fuel nozzle significantly affects the intensity of mixing the fuel with the combustion air and thus the stability of the combustion. The main subject of~this diploma thesis is~determination of~velocity coefficients for nozzles with different geometries. The knowledge of~correct values of~velocity coefficients is a key parameter for the design of~the burner and~its subsequent operation. For the calculation of~velocity coefficients, the exit nozzle velocities were used. For chosen nozzles, a~theoretical exit nozzle velocities were calculated. They were compared with the actual exit nozzle velocities, which were measured experimentally using the hot-wire anemometry, and with velocities, which were calculated using the CFD simulation method.
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Characteristic parameters of combustion of low calorific fuels
Kvapil, Matěj ; Bělohradský, Petr (referee) ; Hudák, Igor (advisor)
The diploma thesis is focused on the combustion of the low calorific gaseous fuels. The first part is devoted to the characterization and usage of low calorific fuels. Then combustion theory focused mainly on emissions and thermodynamics. Next characterization of burners and their modifications for low calorific value fuels is described. Safe storage and handling of chosen gases is also included in the last chapter of the theoretical part. Practical part includes the description of the laboratory experiment, which was a part of this thesis. It consists of the experiment description, experimental plan, calculation and evaluation of emissions, high and low heating value, density, flame temperatures and heat flux. Laboratory experiment was carried out with different fuels. Low calorific fuels were simulated by gradual increase of the concentration of inert gasses in the natural gas. Increased concentration of inert gasses had positive effect on the emissions. Measurement of the flame temperatures confirmed that the decrease of emissions corresponds to the inert gas addition to the noble fuel. Heat flux and thermal efficiency of the combustion was almost identical for each configuration.
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Methods for Determination of Characteristic Parameters of Combustion Processes on the Basis of Experiments and Modeling
Bělohradský, Petr ; Klemeš,, Jiří (referee) ; Žitný, Rudolf (referee) ; Stehlík, Petr (advisor)
The present thesis is concerned with methods for determination and modeling of characteristic parameters of combustion of gaseous fuels. The focus is stressed on formation of nitrogen oxides and heat transfer from hot flue gases into combustion chamber’s walls. Experimental work, which is focused on testing of two burners with suppressed formation of nitrogen oxides, is an important part of the thesis. Its aim is to obtain data that is necessary for further processing and modeling. The work presents two methods that may be used in modeling of characteristic combustion parameters, namely the method based on statistical processing of data and the method based on computational fluid dynamics. The approaches are applied to two devices (burner with two-staged fuel supply, burner with two-staged air supply) with the objective to analyze their parameters. First approach covers detailed planning of burner test prior to its own carrying out (definition of the goal of experiment, choice of input factors and response, experimental plan) and subsequent statistical processing of experimental data. On the contrary, CFD approach offers simulations as an alternative option to traditional experimental methods. The simulation of combustion includes building of computational grid, setup of boundary conditions, turbulence model, heat transfer model and chemical kinetics. Results of simulations are compared with experimental measured data.
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The influence of operating parameters and construction parameters of the low-NOx burner on characteristic parameters of combustion processes
Nykodým, Jiří ; Hudák, Igor (referee) ; Bělohradský, Petr (advisor)
The main aim of the work was the investigation of the effect of operational parameters of the combustion process (combustion air excess, primary fuel ratio) and burner constructional parameters (the pitch angle of secondary nozzles, tangential orientation of secondary nozzles towards the axis of the burner) on the formation of NOx and CO, flue gas temperature, the shape, dimensions and stability of the flame, in-flame temperatures in the horizontal symmetry plane of the combustion chamber and the amount of heat extracted from the hot combustion gases in the combustion chamber’s shell. Experimental activities were carried out in the laboratory of the Institute of Process and Environmental Engineering, which is focused on burners testing. The combustion tests were performed with the experimental low-NOx type burner, namely the two-gas-staged burner. Mathematical model developed based on the experimental data describes the dependency of NOx on the operating parameters of the combustion process and burner constructional parameters. The model shows that increasing air excess and increasing angle of tangential orientation of the secondary nozzles reduce the formation of NOx. The temperature peaks in the horizontal symmetry plane of the combustion chamber decreases with increasing combustion air excess. The thermal load to the combustion chamber’s wall along the length of the flame was evaluated for selected settings. It was validated that the thermal efficiency of is reduced when higher air excess is used.
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