Diss. ETH Zürich, 2006. / Enth.: deutsche Zusammenfassung.

Diss. Naturwiss. Bern (kein Austausch). / Literaturverz.

Universiẗat, Diss., 2006--Kassel.

No description available.

No description available.

Zugl.: Göttingen, Universiẗat, Diss., 1995.

The diploma thesis deals with the issue of pollution of the generated gas after the gasification process and its subsequent cleaning using a barrier filter. The theoretical part of thesis consists of research on the gasification process, the effects on the gasification process, pollutants in the gas and gas cleaning with a focus on the purification of gas from tar. The experimental part of this thesis is devoted to the gasification itself in a fluidized bed gasification reactor in order to test the effect of the catalyst, which was calcined dolomite, the composition of the gas at variable parameters of water vapor and the temperature inside the laboratory filter.

This diploma thesis deals with the issue of pollution of the generated gas during gasification. It consists of two parts. The first part is theoretical, where there is a search describing the course of gasification. There is also an overview of impurities in the generated gas and a description of methods suitable for gas purification. The second part of the work is focused experimentally, where various fillings of the barrier filter are tested during gas cleaning.

Disertation thesis deals with development of hot dolomite filter for the purposes of cleaning of gas polluted by biomass and waste gasification with ash and tar as well as sulphur and chlorine compounds as main pollutants. Gas is then cleaned so that it can be utilized in cogeneration units with combustion engines. This supports advancement of gasification techniques using decentralized power and heat generation especially for design of small scale units. Concrete aims of this thesis are stated in chapter 2. Experimental fluid gasification stend Biofluid 100 has been in operations at Brno University of Technology (BUT) since 2000 and it helps research of biomass and waste gasification. Development of the filter initially utilized needs and experience with the utility during cooperation of BUT and ATEKO Hradec Králové. Water scrubber was used for gas cleaning, however, this method proved to be ineffective. Alternative solutions were considered. Based on literature search, natural catalysts with limestone basis were opted. First part of the thesis presents literature search of this issue. Historic development and description of gasification process are briefly discussed as well as elementary classification of gasification generators. This part is followed by chapters dealing with gas pollutants. Tar – the most significant pollutant – is discussed in a separate chapter which presents tar formation, its classification, characteristics and methods for its removal. Brief summary of requirements on gas properties with respect to its utilization in various applications (especially in cogeneration units) follows. Other part of the literature search part focuses on methods of removal of tar from gas, especially on catalyst methods. Dolomite characteristics, description of dolomite calcination as well as simplified kinetic model of tar cracking using dolomite are presented. Based on literature search, laboratory and verification equipment was designed for the purposes of dolomite properties testing. Equipment description as well as description of experimental stend Biofluid 100 where the experimental tests were carried out can be found in introduction of the experimental part. This is followed by a complete description of pilot equipment design of hot dolomite filter with general description of experimental work process, brief characteristics of the fuel and catalytic material used. Final part of the work comprises of experiment results that were carried out on the pilot equipment. Focus is on efficiency of tar removal in connection with operation temperature, amount of catalytist and material used. Influence of these parameters on gas composition and energy intensity of the whole process under these conditions is mentioned as well. Possibility of autonomous unit operations without electricity heating is briefly outlined. Summary of the most significant results including the potential of future hot dolomite filter development is stated the final part of the thesis.

Carbonatites are unique and enigmatic magmatic rocks of unclear origin, with very specific mineralogy and geochemical properties. They are predominantly composed of magmatic calcite or other carbonate minerals (Le Bas 1987) and have low content of SiO2 (Le Maitre 2002). Origin of these peculiar magmas is still not clear but they appear to represent an important "window" into processes in Earth's mantle. They are considered either as residual melts from a fractionated carbonated nephelinite or melilitite (Gittins 1989; Gittins and Jago 1998), as immiscible fractions of CO2-saturated silicate melts (Freestone and Hamilton 1980; Amundsen 1987; Kjarsgaard and Hamilton 1988, 1989; Brooker and Hamilton 1990; Kjarsgaard and Peterson 1991; Church and Jones 1995; Lee and Wyllie 1997; Dawson 1998; Halama et al. 2005; Brooker and Kjarsgaard 2011), or as primary melts which are were generated from CO2-bearing peridotite through partial melting (Wallace and Green 1988; Sweeney 1994; Harmer and Gittins 1998; Harmer et al. 1998; Ying et al. 2004). Abundances of rare earth elements (REE) are often high in carbonatites because carbonatitic magmas can dissolve these elements much easily than silicate magmas (Nelson et al. 1988). Carbonatitic magma can also dissolve large quantities of Sr, Ba, P and mainly Zr and Nb,...