3/2018
Veronika Kyselová, Lenka Jílková, Karel Ciahotný, Jaroslav Kusý, Josef Valeš, Lukáš Anděl
Sewage sludge is an inevitable by-product from waste water treatment plants. Increasing population leads to increased waste sludge production. In this work, sludges from six waste water treatment plants in the Central Bohemia were tested, which were divided according to the production of drained sludge for 2016. Basic samples were analyzed for individual samples, including water content, ash determination and elemental analysis.
Subsequently, the dried sludge samples were pyrolyzed on a pilot unit at 650 ° C. During the pyrolysis, the volume of the gas evolved, the temperature inside the reactor was taken and samples of the pyrolysis gas were drawn off and the liquid pyrolysis product was withdrawn. After the pyrolysis was completed, the mass balance of the pyrolysis products was carried out and analyzed.
Van Minh Duong, František Skácel, Jitka Hrbek
As the common crop residues in Vietnam, rice husks can potentially be a technically efficient, economically viable and environmentally sustainable bio-energy option, release a considerable heat for thermo-chemical conversion systems. The report provides a comprehensive evaluation in the nature, physico-chemical property, fuel characteristic, ash composition and transformation phenomena of this biofuel. Analysed results show significant calorific value (16-17 MJ/kg), high ash and volatile contents, low S, Cl contents in the test pieces. Low alkali cations were reported in the ash compositions while the obtained Si value was relatively high. Ash softening and fusion processes were determined with heat generated continuously at constant rates (maintained at 550 ± 10 °C for 120 minutes, at 850 ± 10 °C for 240 minutes). First signs of deformation were recorded at temperature above 1450 °C, whereas volume expanding and bursting of internal gas bubbles were not presented. Further elemental determination of ash compositions explains the decomposition of ash-forming elements (Ca, Mg, Fe, Al, K, Na and P), by further oxidation (to higher oxidation states) and partial losses of volatile inorganic compounds.
Martin Staš, Aneta Závodníková, Miloš Auersvald, Josef Chudoba, Pavel Šimáček, David Kubička
Bio-oils from biomass pyrolysis are second-generation biofuels that have, besides fuel applications, a promising potential to be used as a source of valuable oxygen-containing chemicals. A more widespread use of bio-oils requires more detailed knowledge of their chemical composition. In this work, we studied the chemical composition and the physical and chemical properties of bio-oils from slow and fast pyrolysis of the basic building components of biomass, i.e. cellulose, hemicellulose and lignin. The work is divided into two articles. The first part was devoted to (i) the presentation of the results of the analyses of pyrolysis feedstock, (ii) the description of the preparation of bio-oils and (iii) the presentation of the results of the analyses of physical and chemical properties of the bio-oils and their volatile fractions. Here, in the second article, the attention is given to the characteriza-tion of less volatile and nonvolatile components of the prepared bio-oils. High-resolution orbitrap mass spec-trometry was used for these analyses. Using the methods described in both articles, a comprehensive characteriza-tion of the prepared bio-oils was achieved. The obtained knowledge can be helpful to understand the chemical compositions of entire bio-oils and facilitate their more widespread use.
