Ultrasound assisted oxidative desulfurization of diesel fuel

Ultrazvukom potpomognuta oksidacijska desulfurizacija učinkovita je tehnologija za odsumporavanje dizelskog goriva. U ovom radu proučavan je utjecaj temperature, hidrodinamike, omjera oksidans/katalizator, udjela dibenzotiofena i vremena reakcije oksidacije na proces oksidacijske desulfurizacije (ODS) i ultrazvukom potpomognute oksidacijske desulfurizacije (UAOD) modelnog i realnog dizelskog goriva u sustavima vodikov peroksid/octena kiselina i vodikov peroksid/dodekafosfovolframova kiselina. Ispitivanja su provedena u kotlastom reaktoru, pretpostavljena je kinetika pseudo prvog reda reakcije oksidacije. Nakon procesa oksidacije provedena je ekstrakcija rafinantne faze dimetilformamidom te su istražefni utjecaji procesnih parametara; solvent odnosa, vremena i temperature. Analiza sumporovih spojeva nakon procesa oksidacijske desulfurizacije provedena je metodom plinske kromatografije, rendgenske fluorescencijske spektrometrije i nuklearne magnetske rezonancije. Optimalni uvjeti rada u sustavu vodikov peroksid/octena kiselina kod ODS i UAOD procesa bili su temperatura od 70 °C te vrijeme potrebno za postizanje visoke konverzije dibenzotiofena od 180 i 30 minuta. Dok su optimalni uvjeti rada u sustavu vodikov peroksid/dodekafosfovolframova kiselina kod ODS i UAOD procesa temperatura od 70 °C te vrijeme potrebno za postizanje visoke konverzije dibenzotiofena od 90 i 30 minuta. Energija aktivacije procijenjena iz ovisnosti brzine reakcije o temperaturi iznose za ODS proces 86,25 kJ mol^-1, a za UAOD proces 49,17 kJ mol^-1. Najveća učinkovitost procesa ekstrakcije postignuta je s dimetilformamidom pri solvent-odnosu 1 i sobnoj temperaturi.Ultrasound assisted oxidative desulphurization is an efficient technology for desulfurization of fuel. In this research, the effect of temperature, hydrodynamics, molar ratio oxidant/catalyst, dibenzothiphene dosage and time of oxidation reaction on the process of oxidative desulfurization (ODS) and ultrasound assisted oxidative desulfurization (UAOD) were investigated using model and real diesel fuel along with hydrogen peroxide/acetic acid and hydrogen peroxide/tungstophosphoric acid systems. Experiments were conducted in a batch reactor and the pseudo first order kinetics of oxidation reactions was assumed. After the oxidation process extraction of the rafinantne phase was carried out with dimethylformamide and the effects of different process parameters including solvent ratio, time and temperature have been explored. Analysis of sulphur compounds after the process of oxidative desulfurization was conducted by gas chromatography, X-ray fluorescence spectrometry and nuclear magnetic resonance. The optimal operating conditions in the hydrogen peroxide/acetic acid system in the ODS and UAOD processes were temperature of 70 °C and time required to achieve high conversion of dibenzothiophene was 180 and 30 minutes. While, the optimal operating conditions in the hydrogen peroxide/tungstophosphoric acid system in the ODS and UAOD processes were temperature of 70 °C and time required to achieve high conversion of dibenzothiophene 90 and 30 minutes. The activation energy was estimated from the dependence of the reaction rate on the temperature which for the ODS process amounts 86.25 kJ mol^-1, and for the process UAOD 49.17 kJ mol^-1. The maximum efficiency of the extraction process was achieved with dimethylformamide, solvent-ratio of 1 and room temperature