Experimental and theoretical study of toluene oxidation in a catalytic monolith reactor

Zbog neželjenih posljedica koje izaziva emisija hlapljivih organskih spojeva (HOS) u okoliš velika pozornost pridaje se razvoju učinkovitih i ekonomski prihvatljivih postupaka za smanjenje njihovih emisija u atmosferu. Od brojnih metoda za smanjenje emisija hlapljivih organskih spojeva u okoliš poput biofiltracije, adsorpcije, apsorpcije, kondenzacije, itd. posebno se izdvaja katalitička oksidacija kao jedna od najperspektivnijih metoda zbog velikog područja potencijalne primjene, mogućnosti ispunjenja strogih ekoloških kriterija kao i zbog ekonomske isplativosti u odnosu na ostale tehnologije. Katalitički sustavi koji se najčešće primjenjuju u zaštiti okoliša temelje se na monolitnoj izvedbi reaktora. 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, bakra i željeza (Mn-Cu-Fe/Al-Al2O3), kao potencijalnog katalizatora za katalitičku oksidaciju toluena. Također, ispitane su katalitičke značajke pripremljenog katalizatora te su provedene usporedbe s ranije testiranim Mn-Cu/, Mn-Fe/ te MnOx/Al-Al2O3 katalizatorima. U završnom dijelu rada analiziran je rad reaktora i predložen je odgovarajući model za njegov opis te je provedena ocjena prihvatljivosti predloženog modela na temelju usporedbe rezultata dobivenih primjenom modela s eksperimentalnim rezultatima. Nađeno je da monolitni Mn-Cu-Fe/Al-Al2O3 katalizator pokazuje podjednaku aktivnost kao i ranije izučavani bimetalni Mn-Fe/Al-Al2O3 katalizator te nešto manju aktivnost u odnosu na Mn-Cu/ i MnOx/Al-Al2O3 katalizatore. Dobiveno je jako dobro slaganje eksperimentalnih rezultata s rezultatima simulacije prema pretpostavljenom modelu reaktora.Due to the unwanted effects of volatile organic compounds (HOS) emissions into the environment, great attention is given to the development of effective and economically acceptable procedures for reducing their emissions into the atmosphere. Among the many methods for reducing the volatile organic compounds emissions into the environment such as biofiltration, adsorption, absorption, condensation, etc., catalytic oxidation is particularly distinguished as one of the most promising methods due to the large area of potential application, the ability to fulfill strict environmental criteria as well as the economic viability compared to other technologies.The most commonly used catalytic systems in environmental protection is based on the monolithic performance of the reactor. In the theoretical part of this work is given an insight into the issues relating to the emission of volatile organic compounds and review of procedures to reduce their emissions to the environment with special emphasis on the catalytic oxidation processes and appropriate heterogeneous catalysts. In the experimental part is described a process for preparing a metal monolithic catalyst/reactor with a thin layer of a mixed oxide of manganese, copper and iron (Mn-Cu-Fe/Al-Al2O3), as a potential catalyst for the catalytic oxidation of toluene. Also, the catalytic characteristics of the prepared catalyst were tested and compared with the previously tested Mn-Cu/, Mn-Fe/ and MnOx/Al-Al2O3 catalysts. In the final part of the research, the reactor's work was analyzed and it wes suggested a suitable model for its description. The eligibility of the proposed model was based on the comparison between results obtained using the model and experimental results. It has been found that the monolithic Mn-Cu-Fe/Al-Al2O3 catalyst shows almost the same activity as the previously studied bimetal Mn-Fe/Al-Al2O3 catalyst and slightly lower activity compared to Mn-Cu/ and MnOx/Al-Al2O3 catalysts. Very good overlap was made between experimental results and simulation results according to the assumed model of the reactor