Performance Of Pine Gum Hydrogenation Over Spent FCC Catalyst Support Nickel Catalyst And Study Of Reaction Mechanism

The catalytic performance of the prepared catalyst was investigated by pine gum hydrogenation reaction, using a high-pressure autoclave with a double-tier paddle agitator. The effect of preparation of catalyst on pine gum hydrogenation was investigated by single-factor experimental, including nickel loading, reduction temperature, calcination temperature and other factors, using orthogonal experiment to study the effects of various factors on conversion and selectivity of rosin acid in pine gum hydrogenation. The single factor method results show that the optimum catalyst prepared conditions are nickel loading15wt.%, the calcined temperature450℃, the reduction temperature450℃, the reduction time2.5h, the impregnation time2h and the impregnation times1time. The orthometric analysis method show that the optimum catalyst prepared conditions are nickel loading15wt.%, the calcined temperature550℃, the reduction temperature450℃, the reduction time3h and the impregnation time4h. According to range analysis, the order of the effects of five factors on the reaction conversion and product selectivity are all nickel loading> calcined temperature>reduction time>impregnation time>reduction temperature. The variance analysis results show that the order of the effects of five factors on the reaction conversion and product selectivity are all nickel loading>calcined temperature>reduction time>impregnation time>reduction temperature. The effects of Ni loading on the conversion and selectivity of the pine gum hydrogenation are significant.The morphology and properties of spent FCC catalyst and the spent FCC catalyst support nickel catalysts were characterized by SEM-EDS, nitrogen adsorption, XRD, FT-IR, and grain size analysis. The characterization results indicate that the specific surface area of the spent catalyst increases from65.70m2·g-1to67.78m2·g-1after calcined. The spent FCC catalyst’s surface and pore became hardened and coke deposited, resulting in the catalyst inactivation. The calcined spent FCC catalyst expresses layered structure and the pore got clean obviously to some extent. Ni supported on the surface of the carrier and presented as rhombus particles. The Ni catalyst derived from precursor (nickel nitrate) has no absorption at985cm-1of Si-O(H)-Ni, which indicates that there is no valent bond between the metal and the support. The NiO grains get enough reduction, and difficult to be oxidated at room temperature. The particle size of new FCC catalyst are mainly distributed in20μm to70μm, and the particle size distribution of spent FCC catalyst are increased. The particle size of the regenerated spent FCC catalyst support nickel catalyst less than100μm, but the main size distribution range of0μm～50μm. The effect of repeated use of the prepared catalyst was studied. The conversion and selectivity of catalytic hydrogenation of pine gum decreased by1%and0.9%, respectively, from the first time to the seventh time, which shows that the performance of the catalyst is stable.Catalytic hydrogenation of pine gum was investigated over regeneration spent FCC catalyst-supported nickel catalyst. The results show that the optimum conditions of the hydrogenation of pine gum over prepared catalyst are reaction temperature195℃, pressure5MPa, catalyst content5wt.%and reaction time60min. When the stirring speed>400r·min-1and the catalyst particle size<100μm, the internal and external diffusion effect are eliminated, respectively. Reaction temperature, reaction pressure, catalyst dosage and reaction time were chosen to be the factors of orthometric experiment. The results of orthometric experiment show that the optimum reaction condition are reaction temperature200℃, reaction pressure6MPa, catalyst dosage5wt.%and reaction time100min. The order of the effects of four factors on the reaction conversion is reaction pressure>reaction temperature>catalyst dosage>reaction time. The order of the effects of four factors on the reaction selectivity is reaction temperature> reaction time>catalyst dosage> reaction pressure. The effect of reaction temperature on the conversion of the pine gum hydrogenation is significant.The hydrogenation products of pine gum in1h were analyzed and identified by GC-MS, and14components were identified from the hydrogenation products. According to the analyzed results, the network diagram of catalytic hydrogenation of pine gum has been made. We discussed the reaction mechanism, and found that the reaction process not only contain hydrogenation, but also include the dehydrogenation reaction.35peaks were detected in turpentine part of hydrogenated pine gum, and they all were identified. The turpentine hydrogenation reactions are divided into three types, which are double bond hydrogenation, isomerism and hydrate reaction, and nonreaction. In addition, the chromatography and ultraviolet analysis show that the abietic acid and dehydroabietic acid in the product less than2wt.%and10wt.%, respectively, and this accord with national standard GB/T14020-2006.