Samples of bottom ash and fly ash coming from the combustion of lignite with the addition of limestone, from the cocombustion of lignite and wood residue with limestone and from co-combustion of lignite, wood residue, biological sludges from the waste water treatment plant and municipal waste as well with the addition of limestone were examined. Scanning electron microscopy with X-ray microanalyser were used for study of morphology and chemical composition of ash particles. The results were compared with average composition of bottom ashes, fly ashes and input materials found by X-ray fluorescence spectrometry and with phase composition found by X-ray diffraction method. There were proved no significant differences in the character and the structure of individual samples coming from various regimes of combustion., Vladimír Tomášek, Ondřej Šustai, Jana Seidlerová, Zdeněk Klika, Martin Stach, Zdeněk Weiss and Václav Roubíček., and Obsahuje bibliografii
Chemical Quantitative Phase Analysis (CQPA) suggested originally for magmatic rocks (Klika et al., 1986) now is tested for the quantitative mineral determination of coal. This method is based on the optimization procedure. For the evaluation of mineral contents, 5 coal samples were selected and the following analytical data were determined: a) chemical analyses (XRF, titrimetric and gravimetric analytical methods), b) qualitative mineral composition (the X-ray powder diffraction, SEM-EDX and image analyses), c) crystallochemical formulae of minerals. The calculated percentages of minerals obtained by CQPA were compared with calculated percentages of minerals obtained by Raask´s method. Simple statistical evaluation showed that calculation of minerals by CQPA program delivers considerable improvement of results., Michal Ritz and Zdeněk Klika., and Obsahuje bibliografii
Combustion of lignite with limestone, co-combustion of lignite with limestone and wood, and combustion of wood were performed in a circulating fluidised bed in 7 different combustion regimes. The in organic matter composition and properties of all input and output materials were characterized. For each com bustion regime the material streams and the boiler outputs were calculated. The total inorganic mass and the mass of selected trace elements in fuels (Cl, Zn, As, Se, Hg, and Pb) were based on the output of a 1 GW circulating fluidised-bed boiler; additionally, the concen trations of volatile elements (As, Se, Hg) in fly ash (FA) were evaluated in relation to the mass of FA. Element (Cl, Zn, As, Se, Hg, and Pb) enrichment in FA compared with BA was related to the ratio R between the co mbusted mass of organic wood wastes and total combusted fuel. Additionally, the unburned carbon in bottom ash (BA) and fly ash (FA) was determined, and sel ected elements were studied in unburned materials separated from BA. The results show that combustion of wood and/or co-combustion of lignite with wood waste brings about significant environmental benefits., Zdeněk Klika, Lucie Bartoňová and Jana Serenčíšová., and Obsahuje bibliografické odkazy
Most of natural materials contain traces of chlorine and it enters also to the combustion process. Chlorine products of combustions are usually inorganic hydrogen chloride vapors and chloride salts, nevertheless smaller amount of organic chlorine compounds are formed. Simpler of these organic compounds can act as greenhouse and ozone depleting gases; more complex compounds are directly dangerous for their mutagenity or extreme toxity like so called dioxines. Non-fossil natural materials and fuels derived of them can contain more chlorine than common coal. From the published research studies is evident that the formation of organochlorine compounds is limited to the temperature range 300-800 °C. At the higher temperatures, these compounds are destroyed. In the stage of flue gas cooling some chlorine may be by a "de novo" synthesis introduced to the organic form. Well-controlled combustion of alternative fuels need not contribute to the increase of amount of emissions of dangerous chlorine compounds. In our research were moreover studied the fuels with lower chlorine content. The experimental tests of the emissions from large-scale industrial fluid bed boiler indicated that substitution of large percentage of coal by alternative fuels had no significant effect., Kamil Wichterle, Jan Cieslar, Antonín Klečka, Zdeněk Klika and Václav Roubíček., and Obsahuje bibliografii
From 61 coking coals, 36 coal blends were prepared. Using a pilot coke oven, cokes were prepared from both 61 coking coals (Type I cokes) and 36 coal blends (Type II cokes). Coals were characterized by 14 coal characteristics and cokes by Coke Reactivity Index CRI and Coke Strength after Reaction with CO2 CSR. For the study of mutual statistic relationships among experimentally determined characteristics of coals and cokes, the Factor (FA) and Regression Analyses (RA) were used. FA distributed characteristics of coals and Type I cokes into 4 factors while characteristics of coal blends and Type II cokes were distributed into 7 factors. In case of pure coals and Type I cokes, strong relationships with high correlation coefficients (R > 0.60 ) were more abundant than in case of coal blends and Type II cokes. FA was used for the selection of coal characteristics that influence the coke quality the most significantly. These characteristics were then recalculated by RA for the predictions of CRI/CSR of Type I cokes. Predictions of CRI/CSR of Type II cokes were calculated from coal blends by the same procedure. The comparison of the predicted and experimentally determined CRI and CSR indexes showed much more reliable prediction of CRI/CSR indexes calculated from coals than calculated from coal blends. This study also explains the dominant reasons of this observation., Jana Serenčíšová, Zdeněk Klika, Ivan Kolomazník, Lucie Bartoňová and Pavel Baran., and Obsahuje bibliografii
Combustion of coal with limestone (a) and co-combustion of coal with limestone with wood, sewage sludge, soap and PTP (b) were performed in CFB. Inorganic matter composition and properties of all input materials were characterized. For this, chemical and coal petrography analyses of solid samples as well as their leaching tests, unburned carbon, and other properties were determined. There are not striking differences in composition of bottom and fly ashes from combustion/co-combustion data. In fly ash samples higher concentrations of Hg (about 2 ppm), As (about 800 ppm) and chlorine (about 400 ppm) are present than they are in bottom ash (0.002 ppm Hg, 250 ppm As, and 220 ppm Cl). Also relating concentrations of above elements determined in emissions are very similar for combustion/co-combustion regimes (about 0.010 mg.m-3 Hg, 0.027 mg.m-3 As and 24 mg.m-3 Cl). Content of unburned carbon in BA is below 2 wt.% and in FA below 0.6 wt.% in all combustion/co-combustion data. In FA samples the concentration of Hg, As, Se, etc. increases with increasing unburned carbon content, i.e. with decreasing grain size of FA. No significant differences in composition of emissions, bottom and fly ashes as well as in composition of water leachates were found from the combustion regimes I, II, III and IV., Martin Stach, Zdeněk Klika, Martina Nováčková and Václav Roubíček., and Obsahuje bibliografii