Division of Environmental Physics -
Students Faculty of Mathematics, Physics and Informatics, Comenius University Bratislava
Samuel OMASTA alumni student
Bc. study 2014 - 2015
Supervisor: Karol Hensel Title: Tar removal by low temperature plasma Abstract: Biomass is an alternative source of an energy that can be the product of targeted agricultural production or can be obtained from a biological waste. Its most perspective use is its gasification to a syntetic gas (syngas), which calorific value can reach 3 to 7 MJ/Nm3. The gas can be used to obtian either a heat or electric energy by gas incineration in combustion engines and turbines connected to cogenerative units. The gasification of the biomass, however, usually also leads to a production of by-products, such as nitrogen oxides and sulfur oxides, ashes and tars. Tars have a negative effect on the living enviroment and can also cause technical malfunctions in a incineration system. Therefore it is necessary to clean the syngas in order to meet the emission and the technical standards.
In this thesis we discuss the problem of tars and review the existing methods of their removal including the method of low temperature plasma We introduce several types of electric discharges used for the tar disposal, their efficiency in various conditions and by-products. As a part of our work, we constructed a reactor of dielectric barrier discharge type and used it for tar removal. We investigated chemical changes in gases exposed to the discharge in various gases and temperatures. We tested the reactor and its efficiency for naphtalene removal (as a model tar) in various gases, determined its main by-products and their cocentrations and also considered further improvements of the system The experiment results showed that low temperature plasma is capable of effectively removing tar and may be potentially useful for the cleaning of the syngas.