Studium využití pevných produktů pyrolýzního procesu v energetice

Abstract

The present dissertation deals with the use of solid products of pyrolysis process as sorbents capturing gaseous mercury from fossil fuel exhaust. The use of waste products is a hot topic in times of energy crisis. In this dissertation, two complex topics were combined: the production and properties of the solid product of pyrolysis and the reduction of mercury gas concentrations in flue gases produced from large fossil fuel combustion sources. In particular, the issue of reducing gaseous mercury concentrations is a highly debated topic in industrial practice. Due to the introduction of new emission limits at EU level, these tightening rules are having an unpleasant financial and technological impact on many operators. The essence of this work is to offer an alternative route to the production of affordable and sufficiently high-quality sorbents that could be applied in routine practice. The dissertation has also been extended to investigate the possibilities of using solid products from the gasification process. The dissertation is structured into several parts, the smooth continuity of which creates a coherent procedure to meet the set objectives. The first part of the thesis is devoted to the theoretical description of the gasification and pyrolysis process, the fluidised bed combustion system and the legislation in the field of mercury emissions, followed by a description of mercury production in the combustion process. Also included are descriptions of the system for the determination of mercury in flue gas and the technology for its elimination. The second part of the thesis presents the actual experimental and research activities in the field of gasification and pyrolysis of feedstock materials. This is followed by an assessment of the quality of the solid product and its subsequent physical and chemical activation. The research part also describes the analyses for a thorough characterization of the sorbents. The well-defined sorbents are then tested on an experimental track that is directly linked to the fluidised bed unit in which the base fuels are burned. These experiments are carried out to determine the adsorption efficiency of the individual sorbents, i.e. how efficiently the sorbents can reduce the mercury concentration in the flue gas. The thesis concludes with an interpretation of the results, a discussion and a summary of the contributions to science and industrial practice.