Research On Desulfurization Of Light FCC Gasoline

With environmental protection consciousness intensified,People has higher requirement to the product standards.It becomes the key issue in the production of the clean fuels to reduce the sulfur content in FCC gasoline.The content of sulfur thiophene is the highest in the FCC gasoline,accounting for about 70% of the total sulfur.At present,the most widely desulfurization method in domestic country is hydro-desulfurization.Though the desulfurization can make the sulfur content in gasoline meet the national standard,the olefin content in gasoline will decrease and lead octane number reducing.Therefore it is very meaningful to develop a kind of desulfurization technology with high desulfurization efficiency and little loss of octane number.In this dissertation,FCC gasoline was regarded as raw material,and the sulfur was removed by extraction.The dark petroleum products sulfur content analyzer was improved and built a method for the determination of sulfur content in light oil.The effects of different types of extraction agents,different roles of adjuvants on desulfurization rate were investigated.On this basis,complex was carried out and a complex agent was developed which desulfurization rate was high and selectivity was significantly better than that reported in the literature.The effects of extraction time,solvent to oil ratio and extraction stages on desulfurization rate were researched.The results are follows as:?1?The dark petroleum products sulfur content analyzer was improved to build a method for the determination of sulfur content in light oil in which Volume of sulfuric acid should be half of the original in the receiver,taking 3.5ml,the concentration of sodium hydroxide standard solution should be reduced to half of the original(c_NaOH =0.01128mol/L.).The oil sample was placed in the right half of the boat,and the boat should be put in the import of quartz tube.After the improvement the sulfur content could be measured accurately by this instrument.?2?For FCC gasoline with high sulfur content,Extraction agent 1#,2#,3# and 4# had an obvious desulfurization effect.Extraction agent 5# and FCC gasoline were mutually dissolvable,which had no desulfurization effect.The order of desulfurization rate were extraction agent 4#>extraction agent 1#>extraction agent 2#>extraction agent 3#.Assisting agent 1# and assisting agent 2# had the function of reducing oil loss.Optimum compound agent was that extraction agent 2# was 48.2%,extraction agent 4# was 16.2%,assisting agent 1# was 28.5%,assisting agent 3# was 5.9%,assisting agent 5# was 0.12% and assisting agent 6# was 0.99%.Optimum experiment conditions were as follows: the agent/oil ratio of 1?2,agitating time of 35 min,extracted two stages at room temperature.Under this conditions the desulfurization rate could reach 82.5%,the oil loss was 0.25%,the extraction agent loss was 0.343%.?3?For FCC gasoline with low sulfur content,Optimum compound agent was that extraction agent 4# was 31%,extraction agent 5# was 40.5%,assisting agent 2# was 20.5%,assisting agent 4# was 8% and assisting agent 5# was 0.2%.After desulfurization the oil samples were handled by indirect water washing,then the desulfurization rate could reach 85.8%,sulfur content was 6.54ug/g,lower than 10ug/g.