473128 Oxidative-Extractive Desulfurization of Model Diesel Oil By CTA-Type Dawson Type Emulsion Catalyst
The emulsion catalyst along with H2O2 (50 wt-%) was used for extractive catalytic oxidative desulfurization (ECODS) of two kinds of model fuel oil (iso-octane and iso-octane containing 20 v% toluene with 500 ppmw total S, DBT was selected as a S-containing component). Three kinds of solvent including deep eutectic solvent (DES, ChCl: EG with mole ratio 3 (EG) to 1(ChCl)), ionic liquid (IL, 1-butyl-3-methyl imidazolium methyl sulfate (BMIM-sulfate)) and ethylene glycol (EG) were utilized under mild conditions for extraction process. Using Taguchi experimental design, effective parameters such as solvent type, volume ratio of solvent to oil, temperature and contact time on the ECODS were studied. All chosen parameters were studied at three levels by means of L9 orthogonal array (Table 1). The concentration of catalyst in all entries of Table 1 was 7.5 g/L. The efficiency of system containing IL was much better than other systems. The results showed that the EG ECODS system removed DBT better than DES systems.
ANOVA analysis (Table 2) was used to find out the optimized conditions. The result showed that solvent and its volume ratio are the most important parameters. It is found that for the case of paraffinic fuel model (iso-octane) using IL at solvent/oil volume ratio of 1:4 gives the best performance at 50 oC after 60 minutes contact time, while in the case of paraffinic-aromatic model fuel (75 % iso-octane, 25 % toluene, volume basis) higher temperature (60 oC) was required to meet the same condition. The predicted optimized conditions was not similar to any entry of Table 1 for both model diesel oils. So, the validation test was performed. The results of validation tests approved that the predicted optimized removal of DBT were approximately reputational. The nearly 95 % of DBT was removed under optimized conditions from model diesel oil containing only iso-octane. The existence of toluene reduced the efficiency of system and removal of DBT to ~94 % under determined optimized conditions.
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