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Gewählte Master / Diploma Thesis:

Silvester Fail (2010): Two-Stage Gasification Characterisation of Pyrolysis of Woodchips and Pellets.
Master / Diploma Thesis - Institut für Landtechnik, BOKU-Universität für Bodenkultur, pp 66. UB BOKU obvsg

Data Source: ZID Abstracts
Abstract:
Two-stage gasification of lignocellulosic biomass is a promising technology for com-bined heat and power production within capacities of 1-5 MWth. Few scientific data of this system exist on an important scale, especially concerning the application of other biomass feedstock than woodchips. A parametric study was carried out with woodchips and pellets from Pinus pinaster to investigate the influence of temperature (450-750°C), residence time (30min-90min) and biomass flow rate (11-21kg/h) on the pyrolysis stage of a staged gasifier. The three pyrolysis products are: charcoal, gas and condensable volatile matter (tars and water). Increasing pyrolysis temperatures led to a decrease in charcoal yields but an increase in charcoal quality. Gas yields (H2, CH4, CO, CO2, C2H4 and C2H6) as well as their high heating values rose with temperature - mainly at the expense of condensable compounds. Basically less tars but also less reaction water were produced at higher temperatures. Between 25% (at 450°C) and 50% (at 750°C) of the organic compounds in the condensate could be quantified by means of gas chromatography-mass spectrometry. At 750°C the condensable organic fraction was mainly composed of tertiary tars (PAH’s). Energy balances were established at different temperatures to evaluate energy demands, heat losses and the distribution of thermal and chemical powers in the pyrolysis products. Long residence times increased char-coal quantity and improved its quality. Increasing flow rates had the same effect like decreasing pyrolysis temperatures. Generally woodchips and wood pellets behaved similarly during the pyrolysis step, but char derived from wood pellets was more dense (bulk densities of 800 kg/m³).

Beurteilende(r): Weingartmann Herbert

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