Removing Trace Arsenic From FCC Gasoline

Trace arsenic in oil mainly exist in the form of organic arsenic, it is easy to combine with catalysts, such as gasoline hydrogenation catalyst, precious metals reforming catalyst in petrochemical industry, to make them intoxicated irreversibly. Studying and developing some effective dearsenic catalysts becoming an urgent and important research, which has very important scientific and economic value.Based on a large number of relative literatures, researches in reducing arsenic at home and abroad, especially kinds of dearsenic catalysts and dearsenic mechanism. And some arsenic-removing catalysts that using different carriers, spherical and cloverleaf pattern Al2O3, loaded different active components, such as Ni, Cu, Ca, were prepared by impregnation method. These catalysts were been characterized by gas absorption method, which showed catalysts has big specific surface area and pore volume. The XRD showed shat active components existed in the form of oxidation state. Reducing-arsenic performance of catalysts was evaluated by self-made equipment. The Cu-based catalysts showed good dearsenic performance for gasoline, their dearsenic conversion was over 97% at ordinary temperature and pressure.Via studying the arsenic-removing performance in different operation conditions, such as temperature, pressure, airspeed. The increasing of temperature was good to removing arsenic. The increasing of airspeed went against reducing arsenic. Pressure had little effect in 0.5-1.OMPa. And a optimum operation condition was found,50-60℃,0.5-1.0MPa,1.0-2-0h-1. In this condition, dearsenic performance of Cu-based catalysts, loaded different weight, were evaluated. The result showed that the performance was increasing with the increasing of Cu loaded weight part, when it not over 14%.In this paper, ST711-3A dearsenic catalyst was studied. Its specific surface area is 90.8590.85cm2/g, pore volume is 2602 cm3/g, pore diameter is 33.84nm. The XRD showed that active components on ST711-3A was Mn and Cu, which existed in the form of oxidation state. The removing arsenic performance of ST711-3 A dearsenic catalyst was evaluated. In continuous 600h, arsenic in FCC gasoline could be reduced from 132μg/kg to less than 20μg/kg by using ST711-3A dearsenic catalyst. Regeneration of ST711-3A was operated. After regeneration, arsenic in FCC gasoline could be reduced to less than 20μg/kg in continuous 200h.