Study On Catalyst And Process For Hydro-upgrading Of Fluidized Bed Catalytic Cracking(FCC) Gasoline

Production of low sulfur, low olefin and high-octane number clean gasoline is energy economy to maintain its essential requirement for sustainable development. In China, "Limits and Measurement Methods for Emissions from Light-Duty vehicles (Phase IV)" standards will be executed on 2011, in which less than 18vol.%of olefin content,35 vol.%of aromatic content, and 50μg/g of sulfur content in gasoline are required to meet the No. IV emission standards. FCC gasoline constitutes approximate 80%of the total gasoline pool and sulfur content of FCC gasoline accounted for more than 90%of the total value. FCC gasoline consists of great value of olefin (30～55 vol.%) and sulfur (150-1500μg/g).The key issue of this article will focuses on the realization of desulfurization of full-range FCC gasoline by means of the little loss of octane number(RON≤1). Thus, The article have to combine different characteristics of catalysts and feedstock composition on the upgrading process optimization. Conclusions from the experiments are summarized as follow:1 Adopt to two-step hydro-upgrading process:(1) NiS04-Al203 (DQG0905) desulfurization catalyst was prepared and used in the FCC gasoline hydro-upgrading for 140 h. After hydrotreatment, the sulfur decreases from 288 to 71μg/g, with a 75%conversion rate of hydrodesulfurization (HDS); Olefin decreased from 33.2vol.%to 26.2vol.%, with a 21%conversion rate of hydrodeolefinization (HDO); The RON of product lost 3.3 compared with feed. La2O3-HZSM-5(DQG0904) Aromatization catalyst was prepared and used in the FCC gasoline hydro-upgrading for 220 h. After hydrotreatment, the sulfur decreases from 288 to 184μg/g, with a 36%conversion rate of HDS; the olefin decreased from 33.2vol.%to 19.9vol.%, with a 40%conversion rate of HDO; the aromatic content increased from 21.1 vol.%to 26.1 vol.%; the RON of gasoline has only a slight change from 92.9 to 93.3 after the upgrading process.(2) Applying the sequence that aromatization(DQG0904) followed by desulfurization(DQG0905), hydrotreatment was performed for hydro-upgrading of FCC gasoline for 660h. After hydrotreatment, the sulfur decreases from 242 to 73μg/g, with a 70% conversion rate of HDS; the olefin content decreased from 36.8vol.%to 24.9vol.%, with a 34%conversion rate of HDO; the aromatic increased from 18.9.1vol.%to 19.9vol.%; the RON of gasoline has change from 87.8 to 89.4 after the upgrading process.2 CoMo-MgOAl2O3 as desulfurization catalyst is used to study different conditions on catalytic performance and evaluat hydro-upgrading of FCC gasoline. The results show that 240-260℃,4.0-6.0 h-1,2.0Mpa conditions can reduce the sulfur content to< 50μg/g, RON loss of< 1.0, excellent activity and stability.3 A series of TiO2-modified Ni-Mo/HZSM-5 catalysts were prepared by impregnation method with tetrabutyl titanate as a titanium source, and characterized and evaluated by hydrodesulfurization (HDS) activity for full-range fluid catalytic cracking (FCC) gasoline in a continuous-flow fixed-bed micro-reactor. The results show that the coverage of TiO2 on HZSM-5 can weaken the interaction between MoO3 and HZSM-5 and inhibites the formation of Al2(MoO4)3, so that the catalyst desulfurization activity increases substantially.