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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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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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Difuzní proud v hraniční oblasti oblouku měřený elektrickými sondami
Chumak, Oleksiy ; Hrabovský, Milan ; Kavka, Tetyana ; Kopecký, Vladimír
Electric probes were used for investigation of an intermediate layer between the arc and anode surface in regions outside the main current channel. Distributions of a diffuse current and the potential were measured. Resistance and heating of the intermediate layer by diffuse current were evaluated. It was found that not only the value of diffuse current strongly depends on distance from the arc but also the shape of the distribution and the position of the maximum of the current change with the distance. These trends can be explained by expanding of the plasma jet. Evaluated equivalent intermediate layer resistance shows widening of the conductive region in a stream wise direction. Variation of resistivity of the intermediate layer is much higher than variation of the potential drop on the layer. That means that distributed current as well as Joule heating of the layer are generally controlled by distributed resistance.
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Studium difuzního proudu na hranici oblouku pomocí elektrických sond
Chumak, Oleksiy ; Hrabovský, Milan ; Kavka, Tetyana ; Kopecký, Vladimír
Electric probes were used for investigation of an intermediate layer between the arc and anode surface in regions outside the main current channel. Distributions of a diffuse current and the potential were measured. Resistance and heating of the intermediate layer by diffuse current were evaluated.It was found that not only the value of diffuse current strongly depends on distance from the arc but also the shape of the distribution and the position of the maximum of the current change with the distance. These trends can be explained by expanding of the plasma jet. Evaluated equivalent intermediate layer resistance shows widening of the conductive region in a stream wise direction. Variation of resistivity of the intermediate layer is much higher than variation of the potential drop on the layer. That means that distributed current as well as Joule heating of the layer are generally controlled by distributed resistance.
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