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Modelling of oxygen-enhanced combustion process
Naď, Martin ; Juřena, Tomáš (referee) ; Bělohradský, Petr (advisor)
The main purpose of the master´s thesis is the experimental study and the mathematical modelling of the combustion process in which the combustion air is enriched with the high-purity oxygen, i.e. the oxygen content is more than 21 %. This combustion technology is called as the oxygen-enhanced combustion (OEC). Since the experimental work required the manipulation with the pure oxygen, a part of the thesis is focused on risks and necessary safety associated therewith. The detailed description of the combustion chamber as well as of the components necessary for the operation of OEC is included. The main part of the thesis is the computational model of the combustion chamber and the simulation of OEC using CFD methods. The numerical results were then compared with the experimental data acquired during the combustion tests, namely the heat flux distribution along the combustion chamber and the distribution of in-flame temperatures in the horizontal symmetry plane of the chamber.
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Characteristic parameters of oxygen-enhanced combustion process
Dřímal, Jiří ; Hudák, Igor (referee) ; Bělohradský, Petr (advisor)
The thesis is focused on the experimental investigation of the oxygen enhanced combustion technology (OEC), which uses the combustion air with higher concentration of oxygen, i.e. more than 21 %. The OEC technology is used in those industrial applications, which requires higher thermal efficiency, increased productivity, improved character of the flame, reduced equipment cost, lower volume of exhaust gases and improved product quality. Although this technology involves a number of advantages, it is appropriate to mention some of its disadvantages such as refractory damage, inconsistent heating, increased pollutant emission or flame disturbance and/or flashback. The combustion tests of OEC were carried out at the burners testing facility that enables to test many types of burners (gaseous, liquid, or combined). The two-staged low-NOx burner fired by natural gas was used during the tests. The observed parameters include the effect of oxygen concentration in the combustion air on the NOx emissions, heat flux into the wall of the combustion chamber, in-flame temperature distribution in the horizontal symmetry plane of the combustion chamber and also the shape and dimensions of the flame. The combustion tests of the air-enrichment, air-oxy/fuel and O 2 lancing OEC methods were carried out at the burner thermal input of 750 kW and air excess of 1,1 for two combustion regimes, namely one-staged and two-staged fuel supply.
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Characteristic parameters of oxygen-enhanced combustion process
Hudák, Igor ; Hájek, Zdeněk (referee) ; Bělohradský, Petr (advisor)
Diplomová práce se zabývá spalováním zemního plynu při využití vzduchu s vyšším obsahem kyslíku (21–46 % kyslíku ve spalovacím vzduchu), tzv. kyslíkem obohaceným spalováním (OEC). Technologie OEC nalezla uplatnění v průmyslu, kde se jsou nároky na zvýšenou produktivitu, dosažení vyšší tepelné účinnosti, zlepšení vlastností plamene, snížení náklady, či zlepšení kvality výsledného produktu. Ačkoliv OEC přináší řadu výhod, je nutné zmínit i nevýhody jako: poškození zařízení, nestejnoměrné zahřívání, narušení plamene, zvýšené emise anebo zpětný zášleh plamene. Zkoušky proběhly na zkušebně hořáků, která umožňuje testovat hořáky nejen na plynná a kapalná paliva, ale i hořáky navržené pro kombinované spalování při maximálním výkonu hořáku 1 800 kW. Při zkouškách byl použit plynový „low-NOx“ hořák se stupňovitým přívodem paliva. V diplomové práci je popsán vliv obsahu kyslíku ve spalovacím vzduchu na emise oxidů dusíku (NOx), teplotu plamene, přenos tepla ze spalin do stěn spalovací komory, a také vlastnosti plamene, zvláště pak jeho stabilitu, tvar a rozměry. Zkoušky proběhly při výkonech 300 kW, 500 kW a 750 kW, přičemž pro výkon 750 kW proběhly testy jak při jednostupňové, tak dvoustupňové konfiguraci.
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Utilization of biomass for energy purposes
Malínský, Tomáš ; Bělohradský, Petr (referee) ; Recman, Milan (advisor)
The Master’s thesis deals with the renewable source of energy, namely with the biomass, and its utilisation in the Czech Republic. The thesis is divided in to two parts. The first part of thesis is theoretical. It summarises in form of literature search the general problems concerning the biomass, closely burning biomass. The second part focuses on practical utilisation of biomass and it´s burning in small scale boilers, designated for heating buildings. Boilers are detailed described. Attention is focused on machinery with automatic fuel supply. Four possibilities of improving them are described in last part of thesis. Automatic ignition, air supply, preheating of air and continuous regulation of process.
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Higher Heating Value of Sewage Sludge
Mikluš, Michal ; Bělohradský, Petr (referee) ; Houdková, Lucie (advisor)
The thesis is focused on problems of thermal treatment of sludge from wastewater treatment plants. The main objective is to establish a formula for calculating higher heating value (HHV) and lower heating value (LHV) of sludge based on its chemical analysis. The work is divided into two main parts: The theoretical part deals with the characteristics of sludge, thermal treatment of sludge, it isn´t omitted higher heating value and lower heating value. The main topic of a practical part is formulation of eguations for HHV and LHV calculation. Chemical analysis of sludge samples were supplied by TÜV NORD Czech s.r.o., together with the values of HHV and LHV. The calculations were verified by the program MINITAB.
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Burners for high-temperature industrial applications
Naď, Martin ; Hájek, Zdeněk (referee) ; Bělohradský, Petr (advisor)
The main purpose of the bachelor thesis is the discussion of different types of burners and their components. Emphasis is placed mainly on the combustion process with oxygen content more than 21 % in the combustion air, the so called oxygen-enhanced combustion (OEC). The thesis describes characteristic features, possibilities and appropriateness of its use. Since in handling of oxygen there is a level of risk of injury, the thesis also assesses the safety and risks associated therewith. As the combustion process in terms of OEC is significantly different from the conditions of combustion with the atmospheric air, the thesis analyses the impact of the content of oxygen in atmospheric air on flue gas temperature and fuel consumption.
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Testing facilities for burner testing
Sobočík, Robert ; Hájek, Zdeněk (referee) ; Bělohradský, Petr (advisor)
This Bachelor’s thesis is focused on testing facilities intended for burner testing. It deals with a thorough research of accessible material including specialist technical literature and relevant websites in order to gather any available information on current burners and monitor present situation in the market, as well as to provide new information on burner testing facilities and collecting, processing and evaluating the data gained in testing process in Czech and foreign companies.
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Methods for suppressing NOx formation
Pořízek, Vít ; Hájek, Zdeněk (referee) ; Bělohradský, Petr (advisor)
The subject of this bachelor thesis are emissions of nitrogen oxides. The work deals with the suppressing their formation and with the possibilities of their elimination directly from the flue gas. The first part of the work analyses NOx emission limits for all stationary sources of pollution as well as the current effective legislation regarding emission limits of both European Union and the Czech Republic. Further part focused on nitrogen oxides themselves, their characteristics, impact on environment and last but not least on their formation mechanisms. Finally NOx reduction techniques are analysed and described, both primary and secondary.
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Burner testing
Rychter, Aleš ; Hájek, Zdeněk (referee) ; Bělohradský, Petr (advisor)
Bachelor thesis deals with testing of burners used in industrial applications. Overall is work divided into two main parts in which the first one is focused on basic classification of burners according to mixing type, fuel type and air supply system. The Second part of work is then focused on the burner tests. It describes types of tests and test environments in which the combustion tests can be carried out. In terms of tests, it is then necessary to make some important decisions, including the choices of testing fuel, combustion chamber and oxidizer, which have impact on the result. The preparation of tests also includes the developing of test procedure in which it is necessary to include the requirements of specific tests. The tests have to be carried out according to the relevant technical standards. After the realization of every test the evaluation of measured data has to be done and the test report summarizing the results of the test has to be issued. Since during the tests a number of process variables is measured like emissions, temperatures, pressures, flow rates, etc., the necessary instrumentation is described as well.
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