University of Zagreb. Faculty of Chemical Engineering and Technology.
Abstract
Emisija hlapljivih organskih spojeva (VOC) u atmosferu predstavlja izuzetno velik problem, jer zbog velike toksičnosti značajno pridonose onečišćenju voda, tla i posebice zraka. Kao najveći izvori emisija hlapljivih organskih spojeva izdvajaju se industrijska postrojenja, energetska i termoenergetska postrojenja, promet te proizvodnja i uporaba otapala, boja, lakova i sl.
Postoje različiti postupci koji se primjenjuju za smanjenje emisija hlapljivih organskih spojeva u atmosferu, a posebno se izdvajaju postupci heterogene katalitičke oksidacije. Katalitička oksidacija je najperspektivniji postupak za obradu otpadnih plinova u kojima su prisutni hlapljivih organski spojevi, jer ispunjava visoke ekološke standarde i omogućava ekonomsku isplativost u odnosu na druge postupke.
U teorijskom dijelu ovog rada dan je uvid u problematiku koja se odnosi na emisiju hlapljivih organskih spojeva te pregled postupaka za smanjenje njihovih emisija u okoliš s posebnim naglaskom na postupke katalitičke oksidacije i odgovarajuće heterogene katalizatore. U eksperimentalnom dijelu rada opisan je postupak priprave metalnog monolitnog katalizatora/reaktora s tankim slojem miješanog oksida mangana i nikla (Mn-NiOx/Al-Al2O3), kao potencijalnog katalizatora za katalitičku oksidaciju toluena. Toluen je izabran kao modelna komponenta, jer je uobičajeni predstavnik aromatskih organskih spojeva koji uglavnom predstavljaju najveći problem pri razvoju katalitičkih procesa. Katalitička oksidacija toluena provedena je u monolitnom reaktoru pri različitim radnim uvjetima. Pripremljeni katalizator pokazao je izuzetno veliku aktivnost tijekom katalitičke oksidacije toluena, posebice prilikom rada na relativno niskim temperaturama (<200 °C). To ukazuje na mogućnost njegove primjene za uklanjanje štetnih VOC spojeva iz ispušnih i otpadnih plinova u realnim sustavima kao alternative za katalizatore na bazi plemenitih metala.Emissions of volatile organic compounds (VOCs) into the atmosphere is an extremely high problem, because their high toxicity significantly contribute to the pollution of water, soil and especially air. The largest sources of the volatile organic compounds emission are industrial plants, energy and power plants, transport, production, using of solvents, paints, varnishes and etc.
There are different procedures that can be applied to reduce emissions of volatile organic compounds into the atmosphere, including special procedures, such as heterogeneous catalytic oxidations. Catalytic oxidation is a promising process for treatment of the waste gases contained volatile organic compounds because catalytic oxidation can satisfy high environmental standards and in relation to other processes can ensure the economic viability.
In the theoretical part of this work an insight into the issues relating to the emission of volatile organic compounds and review of procedures to reduce their emissions to the environment is given, with an special emphasis on the catalytic oxidation processes and appropriate heterogeneous catalysts. In the experimental part preparation of the metal monolithic catalyst/reactor with a thin layer of a mixed oxide of manganese and nickel (Mn-NiOx/Al-Al2O3) is described, as potential catalyst for the catalytic oxidation of toluene. Toluene was selected as the model component, as representative of an aromatic organic compounds which are attributed as the the highest problem in the development of catalytic processes.
The catalytic oxidation of toluene is carried out in the monolithic reactor at different operating conditions. The prepared catalyst showed an extremely high activity for the catalytic oxidation of toluene, especially when operating at relatively low temperatures (<200 °C). This points to the possibility of its application for the removal of harmful VOC compounds from exhaust and waste gases in the real systems as an alternative to catalysts based on noble metals
