Hydrodesulfurization Performance Of Metal Sulfide Catalysts Supported Mesoporous Zeolites

Nowdays,due to the environmental legislations,the production of low sulfur content fuel oil and even non-sulfur content fuel oil has become the urgent needs of the oil refining industry.Large sulfur-containing molcules such as dibenzothiophene(DBT) and 4,6-dimethyldibenzothiophene(4,6-DM-DBT) are the most refractory to desulfurization.According to previous research,the sulfur removal undergo HDS via two parallel pathways:direct desulfurization(DDS) and hydrogenation desulfurization(HYD),the cause of the steric hindrance from the methyl groups present at the 4 and 6 positions is why 4,6-DM-DBT diffcult to desulfurization.And this leads to the desulfurization of 4,6-DM-DBT mainly favor the HYD pathways. Therefore, to explore the mechanism of 4, 6- DM- DBT hydrodesulfurization and develop highly active hydrodesulfurization catalyst is necessary for the deep hydrodesulfurization.In this paper,the second chapter studied the CoMo catalysts which are prepared by mesoporous supports such as SBA-15,MCM-41 and γ-Al2O3. By comparing the hydrodesulfurization activity of different cataysts and the calculation of reaction kinetics and product selectivity to explore.The characterization results of N2-adsorption and catalytic selectivity showed the supports channel structure can affect the hydrodesulfurization pathways.But the addition of the complexing agent EDTA has little impact on the hydrodesulfurization pathways.In chapter Three,Low-cost mesoporous ZSM-5 zelite was synthesized.We studied the effects of different complexing agents like EDTA,CyDTA,citric acid on metal sulfide catalysts activity for 4,6-DM-DBT hydrodesulfurization.And the influence of quantity of metal carry on the catalysts activity for 4,6-DM-DBT hydrodesulfurization.The activity datas of different catalysts for 4,6-DM-DBT hydrodesulfurization show that for different active metal,every complexing agent play different role in promoting.In addition,within the scope of this experimental investigation,the higher the metal load,the higher the catalysts activity.In chapter Four,when the catalysts prepared with citric acid,we studied how the catalyst precursor solution PH affect the catalysts’ activity.All the catalysts’ activity datas show that when the citric acid was dissolved in distilled water,we get a higher catalyst activity.While,when the citric acid was dissolved in ammonia water,the activity of catalyst is low.