National Repository of Grey Literature 134 records found  1 - 10nextend  jump to record: Search took 0.02 seconds. 
Preprocessing of sewage sludge for pyrolysis process
Ševčík, Jan ; Rusník,, Igor (referee) ; Bodík,, Igor (referee) ; Hlavínek, Petr (advisor)
The concept of sludge management at the level of sludge treating technology of sewage treatment plants, as well as at national, continental or world level, requires fundamental improvement in the interest of sustainable development. Sewage sludge production is continuously increasing. Sewage sludge contains a number of pollutants but also a significant renewable resource for material transformation and / or energy recovery. Sewage sludge is composed of an inorganic mineral part and organic components. Its organic part is a source of energy and nutrients, but also contains harmful pollutants for exapmple heavy metals. However, there are technologies that offer the possibility of neutralizing pollutants while using other sludge components in terms of recycling energy, nutrients and other attractive sludge components. The mentioned technologies include mainly thermal methods of sewage sludge treatment and one of them is pyrolysis. Thessis focuses on sewage sludge prepartation for pyrolysis process, which includes mixing with additives and peletization of prepared mixture for purposes of agricultural or energetical utilisation. Technology for material transformation and energy utilization of sewage sludge, in particular the mentioned pyrolysis or torrefaction, require an insignificant degree of detailed research in order to expand it in the field of sludge management. Indeed, it is not only research that will enable direct correct use of this technology in practice. The results of such research are the basis for the drafting of the relevant legislation, which will subsequently enable the deployment of pyrolysis technologies in practice.
Preparation and basic chemical and physical characterization of biochar from wheat bran
Zouharová, Kamila ; Diviš, Pavel (referee) ; Pořízka, Jaromír (advisor)
At present, the extraction of biochar and its use is a much-discussed topic in the chemical and research fields. The use of biochar is very often declined in the areas of agriculture, waste management, environmental improvement and the fight against global warming. In addition to these sectors, the topic of biochar is also addressed in the production of bio-diesel and bio-oil. Due to the current use of secondary products during biotechnological processes, the presented theoretical and practical study focused on the issue of obtaining biochar from bran by pyrolysis at different temperatures. Part of the practical part was the extraction of biochar from bran and its subsequent analysis, which could be used to characterize biochar obtained from bran by pyrolysis physically and chemically. The characterization of bran biochar was solved by various analytical methods. These techniques yielded, for example, pH, conductivity, particle distribution, elemental composition of biochar, porosity and content of polycyclic aromatic hydrocarbons. Thanks to this study, the properties of biochar and its possible applications in everyday life were characterized in detail. Given the very promising use of biochar obtained from bran, it can be said that this will be a very desirable topic for the future.
Optimisation of fibre-matrix interface in ceramic matrix composite
Halasová, Martina ; Černý,, Martin (referee) ; Chlup, Zdeněk (advisor)
This thesis is concerned to the study of behaviour of fibre composites with ceramics matrix. The composite consists of pyrolysed polysiloxane matrix reinforced by ceramic fibre Nextel 720. Main aim of this work is optimisation of fibre matrix interface through the selection of suitable precursor of the matrix with respect to temperature stability, sufficient strength and reasonable fracture toughness. Samples of matrices were exposed to the long term heat treatment in the range 1100 – 1500 °C. The mechanical properties as hardness and indentation elastic modulus were determined after heat treatment. Selected precursors of matrices were used for composite fabrication. Elastic modulus and fracture toughness at room and elevated temperatures were studied. Discussion is dedicated to the description of changes in mechanical properties with respect to chemical processes taking place during high temperature exposition. Further, reasons of fracture behaviour of composite materials are discussed, and finally, gained knowledge and outlined possibilities of subsequent development are summarised.
Removal of micropollutants from wastewater by adsorbtion.
Trávníček, Jakub ; Macsek, Tomáš (referee) ; Hlavínek, Petr (advisor)
The aim of the thesis is to create a research on the issue of adsorption of micropolutants with a subsequent focus on biochar. The first part therefore deals with the micropolutants themselves, the origin of their formation in wastewater and their negative impact on the health of organisms. It also deals with adsorption technology, discusses its basic knowledge necessary to grasp the topic and describes known adsorbents and their use. It pays special attention to biochar. The second part of the thesis deals with practical filter tests of adsorption abilities of biochar on wastewater from tunnel maintenance and treatment carried out in the laboratory of the AdMaS centre.
Energy use of biomass
Bouchner, Michal ; Špiláček, Michal (referee) ; Baláš, Marek (advisor)
The aim of this bachelor thesis is research of technologies for energy usage of biomass with concentration to production of electricity. In the first part of thesis are analyzed and described technologies producting electricity. In the second part are described suitable types of biomass for each aplication. Following part deals with used aplications for production of electricity in the Czech Republic. Last part shows specific technologies used in the Czech Republic.
Less usual technologies of biomass utilization
Červenáková, Jana ; Brázdil, Marian (referee) ; Baláš, Marek (advisor)
The main aim of the bachelor thesis is to elaborate less usual technologies of biomass utilization. In the first part of thesis are individual technologies described and divided. The second part of the bachelor thesis describes the concept of biomass and its specific featuress. The last part describes selected applications of less traditional technologies in the Czech Republic which produce electric power by using biomass fuel.
Removal efficiency of selected drugs by various sorptive materials from water
Štofko, Jakub ; Mravcová, Ludmila (referee) ; Vávrová, Milada (advisor)
This thesis deals with sorption of selected drugs from model water by various sorption materials. Contamination of water resources by the pharmaceutical industry is a major problem today. Wastewater treatment plants, whose technological processes are unable to completely remove them, have a significant share in the penetration of these substances into the environment. At present, attention is paid to alternative materials that are capable of eliminating these substances. One of the potential sorption materials is biochar as one of the main pyrolysis products. This work focused on the assessment of the sorption properties of the different types of biochar and commercially used active charcoal. The sorption properties of the individual materials were compared with respect to the non-steroidal anti-inflammatory substance ibuprofen and the sulphonamide antibiotic sulfamethoxazole. The results of vial experiments were analysed on a liquid chromatograph with mass detection.
Evaluation of technology for the biomass incineration.
Havelková, Pavla ; Máša, Vítězslav (referee) ; Jícha, Jaroslav (advisor)
This bachelor’s thesis is interested in description of the biomass and its utilization as a renewable energy source. The text is specified in the production of the biomass and also an overview of the technologies used in its processing and utilization, which is both energy and non-energy. Then, this thesis deals with the description of the various devices, in which the biomass is processed.
Determination of organic compounds in biochar produced by microwave torrefaction of biomass
Meindl, Jiří ; Vávrová, Milada (referee) ; Mravcová, Ludmila (advisor)
The thesis is focused on a determination of polycyclic aromatic hydrocarbons (PAHs) contained in dried pelletized sewage sludge and pelletized biochar. Biochars were made in mild conditions by microwave torrefaction of prepared sewage sludge. There were analyzed and quantified the 34 of standardized PAHs compounds in two series. The first serie, also called “Sada 1”, has been aimed at comparison of extraction methods for the chosen sample of sewage sludge and the sample of biochar. In serie “Sada 1”, there were compared efficiencies of chosen type of solvent or solvent mixture by comparison of yields for 34 standardized analytes in a sample of biochar and a sample of sewage sludge. There were compared also to total yields of PAHs and to number of quantified compounds in analyzed samples. The most reliable extraction method has been used for the next analyses of samples in the second serie called “Sada 2”. In Sada 2, there were compared different samples of the same type (e.g. biochar, sludge). The origin of sewage sludge (small or big sewage treatment plant expressed as PE) and used additives (cellulose, chaff, hay) as modificators for torrefaction process were variables for different type of sample. The results of analysis were identification of the most suitable sewage sludge and additive to be used as modificator for microwave torrefaction process. The main goal of correctly chosen sludge and additive was to minimize production of PAH’s during torrefaction and in samples of biochar.
Behaviour of the Interface of Low Toughness Materials
Halasová, Martina ; Pabst, Willi (referee) ; Tatarko, Peter (referee) ; Fintová, Stanislava (referee) ; Chlup, Zdeněk (advisor)
The work is focused on evaluation of factors influencing behaviour of interface in low toughness ceramic materials reinforced with fibres. The main aim was to characterise processing effects influencing the quality of fibre-matrix interface, with respect to final behaviour of composites at various loading type. The partial goal was to map the possibility of influencing the composite material by choice of matrix material, eventually by change of its processing, leading to change of interfacial properties without need of modification of reinforcement surface. The materials used in studied composites as a matrix were based on thermal transformation of polymer precursors, thus, the resulting materials were characterised in partially as well as in fully pyrolyzed state. Behaviour of interface in cpomposite materials was first evaluated from the global behaviour (i.e., change of mechanical properties) and in chosen representative composites also from the point of local changes in close surrounding of the interface (i.e., microstructure, chemical processes, fracture-mechanic processes, etc.) due to thermal exposition. In experiment were used particularly composite materials prepared by pyrolysis of polysiloxane resins reinforced by basalt fibres or Nextel™720 fibres. With respect to thermal resistance of the reinforcement, the basalt reinforced composites contained only partially pyrolyzed matrix (i.e., to temperature of 800°C), and in composites with Nextel™720 reinforcement was the matrix in form of fully pyrolyzed polymer into ceramic (SiOC). At partial pyrolysis of polysiloxane resin occurs rapid change of behaviour at temperature of 600°C. It was demonstrated, that around this temperature the formed interface with basalt fibre exhibits optimum adhesion/strength, allowing to reach sufficient level of composite strength at acceptable fracture toughness. Above temperature of 750°C occur significant difusion processes in the area of the interface and formation of new crystalline phases in the fibre, what deteriorates the fibre strength, and on the contrary, strengthen the interface cohesion, what leads to degradation of properties of the whole composite. At composite materials determined for high temperatures, reinforced by Nextel™720 fibres, was detected significant resistivity against oxidation caused especially by fully pyrolyzed matrix. As similarly important factor was observed the formation of mullite interphase in surface area of the fibre. Volume changes caused by formation of the interphase, difusional transport of the matter and thermal exposition led to formation of thermally and stress-induced micro-cracks, weakening interfacial surrounding in matrix as well as in fibre. This mechanism in contrast to amplifying chemical bond between fibre and matrix led to preserving of the composite properties also at high temperatures up to 1500°C. The work also dealed with effects of loading rate, where in contrast to static loading were observed different failure mechanisms. Realized research led to description and explanation of the influence of the fibre-matrix interface by change of matrix material processing parameters, which allow processing of economically advantageous and thermally stable composite.

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