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Zplynování biomasy v termickém plazmatu
Hrabovský, Milan
The gasification of biomass in thermal plasma is discussed and the processes are analyzed. Heat needed for production of syngas was determined from heats of wood combustion and thermodynamic analysis of all processes in the reactor. The kinetics of the process of gasification in plasma flow is analyzed. Experiments with biomass treatment in plasma reactor with hybrid gas/water-stabilized arc are described. Effects of plasma power, material feed rate and flow rate of reaction gases were studied. Syngas with high content of hydrogen and carbon monoxide was produced. No presence of complex hydrocarbons or tar was detected.
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Vliv připojeni oblouku k anodě na proud termického plazmatu
Chumak, Oleksiy ; Kavka, Tetyana ; Hrabovský, Milan
The paper examines an effect of an argon amount on the thermal plasma jet generated from water/argon mixture in a dc arc plasma torch. In spite of an increase of plasma velocity with an addition of argon a decrease of plasma jet length is observed for bigger argon amount in the plasma. The investigation was based on an analysis of a jet structure based on imaging of the plasma jet by a CCD camera. Statistical processing of plasma jet photographs provided information about a jet shape and its fluctuations space distribution. It was found that an argon amount increase caused significant intensification of the plasma jet fluctuations.
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Měření excitačních a ionizačních teplot v expandujícím proudu H2O-Ar plazmatu
Sember, Viktor ; Mašláni, Alan
Optical emission spectroscopy is used to determine the temperature in a plasma jet expanding from the H2O-Ar dc arc torch into a chamber maintained at a pressure of 10 kPa. The excitation and rotational temperatures are derived from relative intensities of argon atomic and ionic lines, and from the UV OH band at 306.357 nm, respectively. The ionization temperature is obtained from the intensity ratio of argon ionic and atomic lines, using electron number density calculated from the Stark broadening of hydrogen H line. The structure of the plasma jet is characterized by isocontours of electron number density and intensity of atomic and ionic lines. In the expansion region, the ionic excitation temperature is found close to the ionization temperature and much higher than the excitation temperature of argon atoms, which is close to the rotational temperature of OH radical. In the normal shock region, all the measured temperatures tend to be equal.
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Zplyňování dřeva v plazmatu a produkce plynu s nízkým obsahem dehtů
Hlína, Michal ; Hrabovský, Milan ; Kopecký, Vladimír ; Konrád, Miloš ; Kavka, Tetyana ; Skoblja, S.
Tar content in gas produced by the gasification of biomass always plays an important role because high tar content disables some potentialities of the further treatment of the produced gas. There is a strong effort to produce gas with low tar content from this point of view. High concentrations of hydrogen and carbon monoxide also advance possibilities of the usage of the produced gas. Experiments were carried out in a reactor for plasma gasification equipped with hybrid gas-water stabilized DC torch. They confirmed that the reactor is absolutely suitable for this purpose mainly due to extremely low flow of plasma composed of argon, hydrogen and oxygen and its high inner temperature. The measurements of the tar content, using wood as a treated material, were based on SPE method and the determination of benzene and toluene in a gas phase revealed really low concentrations of tar, mostly below 10 mg/Nm3.
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Statistické zpracovani obrázku plazmatického prouděni pro vizualizace nestabilit
Chumak, Oleksiy
The structure and stability of a thermal plasma jet were studied on the basis of statistical analysis of images of a plasma jet taken by a fast shutter camera. The space distribution of the mean value and the standard deviation of image brightness were evaluated from a sequence of images. The short exposure time ensured imaging of the momentary state of the jet while analysis of a sequence of images provided information about jet fluctuations. Effect of arc current was investigated. Arc power increase led to higher fluctuations of the jet, although it caused increase of the jet length.
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Ofukování termického proudu plazmatu generovaného plazmatronem
Kavka, Tetyana ; Hrabovský, Milan ; Chumak, Oleksiy ; Kopecký, Vladimír
The ambient air is entrained intensively into atmospheric pressure thermal plasma jets. A system for shielding plasma jet has been used to improve jet characteristics and reduce oxygen content. Different gases have been applied as a shroud gas – argon, acetylene, methane, mixtures of acetylene-nitrogen and hydrogen-nitrogen. All shroud gases used in experiments affected plasma jet making the profiles of the jet characteristics flattened with higher temperatures and velocities and reduced amount of oxygen.
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