Study On Preparation And Hydrogenation Isomerization Of Me / SAPO - 11 Bifunctional Catalysts

In this work silicoaluminophosphate molecular sieve SAPO-11 molecule sieves with different Si content were synthesized, using DBA and DPA as template, respectively, and the properties of the samples were characterized by XRD, SEM, XRF, N2 physical adsorption, Py-IR and H2 chemisorption method. The catalytic performance of the catalysts was evaluated in the probe-reaction of hydroisomerization of n-decane on the fixed bed micro-reaction apparatus. It exhibited that the kind of template, compose in the mixture gel and crystallization time had great influence on the texture, acidity and catalytic performance of synthesized SAPO-11 molecular sieve. The bifunctional catalyst 0.5Pd/S11-B(0.4) loaded 0.5 wt. % Pd on the SAPO-11 molecular sieve synthesized using the DBA as template with Si O2/Al2O3 of 0.4 in the reaction gel at crystallization of 24 h possessed the excellent catalytic performance, the yield of i-decane reached 78.5 % under conversion of n-decane of 85.9 %.The bifunctional catalysts Me/SAPO-11 loaded noble metal Pd and phosphide of transition metal Ni2 P on the SAPO-11 molecular sieves were prepared. The metal sites and acid sites ratio(CPd/CH+) and effective acid sites numbers between two metal Pd sites(nas) on the catalytic performance of n-decane isomerization over the x Pd/S11 catalysts with various palladium loading was studied. When the CPd/CH+ was between 0.09 ~ 0.27, x Pd/S11 catalyst exhibited both higher conversion of n-decane and selectivity for i-decane due to the excellent synergetic catalytic effects between the metal sites and acid sites. The selectivity for i-decane was 89.8 % at the n-decane conversion was 90.8 % over the 0.3Pd/S11 catalyst was obtained. Moreover the catalytic performance of n-decane isomerization over the Ni2P/S11 catalysts prepared by TPR method with various Ni/P ratio and Ni2 P loading was studied, higher n-decane conversion of 83.1 % and selectivity of 78.5 % for i-decane over the 3.8Ni2P(1.0)/S11 catalyst was received.Series of hierarchical SAPO-11 molecule sieves were successfully prepared with the carbon nanotubes and TPHAC as mesoporous templates, respectively. The influence of contents of mesoporous template and the treatment method of the raw material used for synthesis of the molecule sieves on structure, acidity of the hierarchical SAPO-11 molecule sieves and their catalytic performance was discussed. It showed that the metal dispersion on the Me/SAPO-11 catalysts was increased due to the introduction of mesopore, which resulted in promoting diffusion of branched isomers within the pore canal of themolecule sieve in the n-decane isomerization reaction and the increasing the selevtivity for branched isomers. The excellent catalytic performance in selectivity of 79.6 % for i-decane at n-decane conversion of 84.6 % was obtained over the 3.8Ni2P/H-S11-6C catalyst, the selectivity for DMC8 in i-C10 was raised to 25.7 % from 17.5 %, obtained over the catalyst loaded on micropore SAPO-11 molecule sieve.