| Deep desulfurization of diesel fuel has become an increasingly important subject worldwide due to the upcoming legislative regulations to reduce sulfur content in most countries. Oxidative desulfurization (ODS) appears to be particularly promising and is currently receiving growing attention. ODS combined with extraction is considered one of the most promising processes. The greatest advantage of oxidative desulfurization compared with the conventional hydrodesulfurization (HDS) process is that it can be carried out in the liquid phase under very mild conditions-near room temperature and under atmospheric pressure.The two amphiphilic catalytic-oxidation systems, H2O2/Q3PW12O40, H2O2/ Q3PMO12O40, used to removal of sulfur in the FCC diesel oil were investigated in this article, respective1y. And the extraction process was discussded in detail.The results on the catalytic-oxidation/extraction desulfurization of the FCC diesel oil by H2O2/Q3PW12O40 indicated that: [(C18H33) N (CH3)3]3[PW12O40] displayed the higher catalytic activity compared to [(C16H33) N (CH3)3]3[PW12O40]. The temperature had great influence to sulfur removal of the diesel oil. Sulfur removal efficiency was increased with the increase of temperature and reached the maximum at 80°C. It decreased slightly when the temperature continue to increase. Sulfur removal efficiency could be improved with the amount of the catalyst increased moderately. The sulfur removal efficiency increased as the hydrogen peroxide solution amount enhanced, and then reduced a little. The optimum oxidation conditions, which were reaction temperature of 80℃, the catalyst amount of 0.601% wt, reaction time of 30min and H2O2/sulfur molar ratio (H2O2/S) of 5, were obtained. As a co-catalyst formic acid could enhance the desulfurization of diesel oil and the sulfur removal efficiency added 3 % with VHCOOH/VH2O2=0.6. The best extraction conditions ofγ-butyrolactone were: extraction time 2min, room temperature, the oil to agent volume ratio of 2:1, extracted for two times and the sulfur removal efficiency and yield of the diesel oil were 89.7%, 85.0%, respectively. The ideal extraction conditions of NMP were: extracted with 90%NMP, room temperature, the volume ratio of oil to agent of 2:1 and extracted for one time and the sulfur removal efficiency and yield of the diesel oil were 82.3%, 100%, respectively or extracted for two times, the sulfur removal efficiency and yield of the diesel oil were 91.4%, 94.5%, respectively.The results on the catalytic-oxidation/extraction desulfurization of the FCC diesel oil by H2O2/ Q3PMO12O40 indicated that: the temperature had great influence to sulfur removal of the diesel oil .The sulfur removal efficiency was increased and the color of the diesel oil became darker with the increase of the temperature; The sulfur removal efficiency of the diesel oil was increased as the amount of the catalyst was increased, However, it decreased slightly when amount of the catalyst further increasing; the extension oxidation time influence the desulfurization effected a little, The sulfur removal efficiency of the diesel oil was increased as the amount of oxidizing agent was increased and reached to the highest at H2O2/S = 5. It did not increase when further increasing the H2O2/S molar ratio, on the contrary, it decreased slightly. The optimum oxidation conditions,which were reaction temperature of 80℃, the catalyst amount of 0.510%, reaction time of 30min and H2O2/S of 5, were obtained. As a co-catalyst formic acid could enhance the desulfurization of diesel oil and the sulfur removal efficiency added 3.1% VHCOOH/VH2O2 = 1. Under the extraction condition : the volume ratio of oil to agent 2:1 and extracted for one time, the sulfur removal efficiency and the yield of the oil were 88.3% and 85.0%.The IR spectra of the oxidized diesel oil showed that the oxidation was able to convert the refractory sulfur-containing compounds in the diesel to the corresponding sulfone compounds. |
PDF Full Text Request