Study On The Hydrogenation Catalyst For Reforming Heavy Aromatic Oil

The olefin is the main factors to affect the stability and color of thereforming heavy aromatic oil so the hydrotreatment of the oil is verysignificant and valuable to the effective use of the oil.This paper studied different Alumina carriers, the corresponding catalystsprepared by the impregnation method with Pd as the main catalyst. Weresearched the reaction performance of the catalysts on the hydrotreatment ofthe reforming heavy aromatic oil with the fixed bed micro reactor. The changeof the olefins and the naphthyl aromatic hydrocarbon in the reaction productswere determined by the micro-coulomb bromine index detector and the gaschromatograph. The catalysts and supports were characterized with XRD,BET, H2-O2titration, NH3-TPD and TG-DTA. The main contents and resultsare as follows:1The alumina supports were prepared by calcining the pseudo-boehmiteat different temperatures. A series of catalysts supported palladium wereobtained. Investigated the influence of calcining temperature on the catalystperformance, the results showed that γ-Al₂O₃calcined at700℃was the mostappropriate support. The suitable content of Pd in the catalyst was0.2%.However, the stability of the catalyst was not ideal. 2Ni-γ-Al₂O₃supports were prepared by blending Ni andpseudo-boehmite. The hydrogenation reaction results of the Pd/Ni-γ-Al₂O₃catalysts alladium showed that the suitable additive content of Ni was2%. Thereaction performance of the catalyst was basically steady after500h. Optimumreaction conditions of the catalyst were temperature80℃, pressure5MPa,Liquid space velocity2h-1, hydrogen to oil volume ratio500:1. The conversionratio of olefin in the raw material and the selectivity of naphthyl aromatichydrocarbons were respectively were92.37%and98.4%in this condition.3The multiplex α-Al₂O₃supports were prepared by blending andcalcining the mixture of α-Al₂O₃and pseudo-boehmite. The catalyst of thesupport had F-35γ-Al₂O₃displayed the best performance of the hydrogenationreaction to the reforming heavy aromatic oil. The fitting content of supportedPd of the catalyst was0.25%. The fitting reaction conditions of the catalystwere temperature100, pressure5MPa, Liquid space velocity-100℃2h1, hydrogento oil volume ratio300:1. The conversion ratio of olefin in the raw materialand the selectivity of naphthyl aromatic hydrocarbons were respectively91.22%and98.32%in this condition. The reaction performance of the catalystwas basically steady after360h.4We exploringly researched the preparation and the hydrotreatmentperformance of Ni-MoC/γ-Al₂O₃to the reforming heavy aromatic oil. Theresults showed that the suitable content of Mo of the catalyst was12%, thehydrotreatment performance of Ni-Mo2C/γ-Al₂O₃was similar to the catalyst supported palladium on the aforementioned reaction conditions.5XRD results indicated that the pseudo-boehmite had the γ-Al₂O₃phasecalcined at700℃, there was only the γ-Al₂O₃phase in the Ni-γ-Al₂O₃supportand the multiplex α-Al₂O₃support. BET and NH3-TPD results showed that thesurface area and acidity of the Al₂O₃support decreased with the increase ofthe calcining temperature of the pseudo-boehmite, the surface area and acidityof the γ-Al₂O₃support decreased after mixed with Ni, the surface area andacidity of the multiplex α-Al₂O₃support increased with the increase of thecontent of the pseudo-boehmite. H2-O2titration results showed that thedispersion of Pd on the support decreased with the decrease of the surface areaof the support and the increase of the content of Pd on the support. TG-DTAresults show that the coke of the reacted catalyst decreased with the decreaseof the acidity of the catalyst.