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Hybridly stabilized arc as a tool for biomass gasification and the degradation of water-soluble organic compounds
Hlína, Michal ; Pacáková, Věra (advisor) ; Jelínek, Ivan (referee) ; Pekárek, Stanislav (referee)
(EN) A plasma torch (the source of plasma) with Gerdien arc was utilized as the source of energy in a reactor for gasification of biomass and for the degradation of organic compounds dissolved in water circling around the arc where the dissolved compounds are exposed to an intensive ultraviolet radiation. Thermal plasmas have electrons, ions and neutrals in thermal equilibrium and are quite often characterized by higher pressures and temperatures than nonthermal plasmas. Therefore, thermal plasmas generally carry a huge amount of energy which can be employed for heating and subsequent gasification of various types of materials. Thermal plasma gasification reactors are operated at higher temperatures than conventional reactors which results in a very good composition with a high percentage of hydrogen and carbon monoxide in produced synthetic gas. Spruce sawdust and spruce pellets were gasified at feeding rates up to 60 kg/h. Oxidizing media such as water, carbon dioxide, oxygen or their mixtures had to be added to the reactor during experiments to avoid the formation of solid carbon. The compositions of produced gas significantly corresponded to calculated compositions and the produced gas was of high quality - hydrogen content approximately 45 % vol., carbon monoxide approximately 48 % vol., a...
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Enthalpy Probe Diagnostics of Steam/Argon Plasma Jet
Hlína, Michal ; Hrabovský, Milan
DC plasma torch with argon/water stabilization features extreme properties of the exiting plasma jet. The plasma mass flow rate is very low while the temperature reaches very high values. Plasma properties were measured by enthalpy probe connected to a mass spectrometer. The measurements of enthalpy, temperature, density and dynamic pressure were carried out for three different arc currents and at atmospheric pressure. The dependences of plasma characteristics on arc current were shown.
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Photocatalytic Decomposition of Wastewater from the Production of Explosives
Brom, Petr ; Brožek, Vlastimil ; Březina, Václav ; Hlína, Michal ; Mastný, L. ; Novák, M.
Water stabilized plasma generator WSP® H-500, operating on the principle of Gerdien arc was used for the photocatalytic decomposition of furazan- and picraminate-based explosives. The generator emits intensive radiation in the range of 300-660 nm, which allows not only to activate photocatalysts based on TiO2, but also other semiconductor oxides with a narrower band gap, such as tungsten oxide. The photocatalytic decomposition of sewage and slurries containing the potassium salt of 4-hydroxy-4,6-dihydro-5,7- dinitrobenzofurazane-3-oxide (KDNBF) or sodium picraminate (NaC6H4N3O5) was performed using the anatase paste and newly developed photocatalyst produced by the company Precheza a.s. The photocatalytic reactor was built using a quartz tube coil with an internal volume of 650 ml, with a nominal size of the irradiated area of 7.5 dm2 (value reduced by the area of the gaps between coil turns) to enable the flow the processing solution or suspension of up to 10 l / min. The centre of the coil is exposed to the plasma jet with the intensity\nof 80 kW; of which 15 kW is transformed into the light radiation. 11% of the radiation output was used for the presented experiments. The time of exposition was 45 mins and 20 l of solution were treated. In the case of KDNBF, 90% of the compound was decomposed. Moreover, 100% of sodium picraminate were decomposed after 15 minutes into low-molecular inorganic compounds. Advantage of the assembly is the ability to treat highly dangerous chemical compounds in a closed cycle and test selective catalyst
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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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