Study On Reaction Process Of Deep Aromatization Coupled Hydrorefining Of Full FCC Gasoline Distillate

In response to the trend of the era of refining and chemical integration,in view of the overcapacity of FCC gasoline,the downstream aromatics,ethylene,and propylene are in short supply.Based on the current operating conditions of the refinery enterprises,combined with the characteristics of FCC gasoline,this paper adds the coupling of deep aromatization to FCC gasoline.The hydrogen refining reaction process has been studied in depth.The effect of the reaction process conditions on the aromatization reaction performance of FCC gasoline was investigated,and it was found that the reaction temperature is the main process factor affecting the aromatization reaction of FCC gasoline.With the increase of reaction temperature,the reaction activity of FCC gasoline gradually increases,and the increase of reaction pressure and volumetric space velocity will lead to the decrease of its aromatics selectivity.The hydrocarbon composition characteristics of different narrow fractions of FCC gasoline and their aromatization reaction performance were studied.It was found that with the increase of the real boiling point cutting temperature,the content of olefins in the narrow distillate of FCC gasoline decreased rapidly,while the content of aromatics increased rapidly,and its reaction activity gradually decrease,but the selectivity of aromatics shows a trend of first increasing and then decreasing.The reactivity of each olefin in FCC gasoline shows the law of C₅⁼>C₆⁼>C₇⁼>C₁₀⁼>C₉⁼>C₈⁼.Based on the difference in the reactivity of the narrow fractions of FCC gasoline and olefins with different carbon numbers,a method of cutting the fractions for deep aromatization of FCC gasoline was proposed.The aromatization reaction law of key hydrocarbon components in FCC gasoline gasoline in the axial direction of the reactor was explored,and it was found that in the first 60%of the catalyst bed axis,the C₅and C₆olefins in the full FCC gasoline distillate showed higher reactivity,but the aromatics were selected.The reaction activity of C₈～C₁₀olefins in full FCC gasoline distillate gradually becomes prominent in the last 40%of the axial direction of the catalyst bed,but its reaction activity is lower,and the aromatic selectivity gradually increases and gradually becomes flat.On this basis,a grading method of aromatization catalyst matching the axial reaction law of the reactor was proposed from the molecular level.A seven lumped kinetic model of FCC gasoline aromatization in the presence of hydrogen was established,and it was found that olefin hydrogenation,olefin isomerization,and cyclo-olefin dehydroaromatization reactions mainly occurred in the process of FCC gasoline aromatization.Hydrogenation rate of olefins:k（n-olefins）>k（i-olefins）.Aromatization rate of olefins:k（cyclo-olefins）>k（n-olefins）>k（i-olefins）.Aromatics of alkanes structured rate:k（cyclo-paraffin）>k（i-paraffin）>k（n-paraffin）.The credibility of the model is high,which improves the flexibility and raw material applicability of the FCC gasoline deep aromatization catalyst grading scheme.A combined process of deep aromatization coupled with hydrotreating of full FCC gasoline distillate was proposed,and the reaction process conditions were preliminarily optimized.It is found that when the aromatization temperature of light FCC gasoline distillate and heavy FCC gasoline distillate is 400°C and 420°C,and hydrorefining temperature is300℃,and reaction pressure is 2.0 MPa,and LHSV is 1.5 h^-1,.and V_H2/V_Oilis 300:1,the aromatics in the light FCC gasoline distillate product increased by 8.83 wt%,the olefin content was reduced to 0.53 wt%,the sulfur and nitrogen compounds were almost completely removed,and the liquid yield was 92.01%;The aromatics in the heavy FCC gasoline distillate product increased by 8.23 wt%,the olefin content decreased to 1.43 wt%,the sulfur content decreased to 2.86 ppm,the nitrogen content decreased to 1.64 ppm,and the liquid yield was 94.88%.