Influence of Pt Metal Center/Acid Center Concentration Ratio on Hydroisomerization Performance Over Pt/Beta Zeolite
Industrial Beta zeolite was used as raw material and loaded with different contents of Pt to achieve the catalysts with various metal center/acid center concentration ratios(cM/cA),and their physicochemical properties were characterized;the hydroisomerization reactions of different cM/cA catalysts were evaluated using n-heptane as a model compound.The results show that Pt particles are uniformly loaded on the external surface of zeolite,which have no effects on the structure of zeolite,and the acidity of the loaded samples is decreased slightly.For the n-heptane isomerization reaction activity of catalysts,when the cM/cA is less than 0.037,the reaction process is controlled by the amount of metal center,and a large number of multi-branched i-heptane and cracked products are formed.When the cM/cA is greater than 0.285,the reaction process is dominated by the acid center amount,and hydrogenolysis reaction occurs.At the reaction pressure of 0.4 MPa,reaction temperature of 207 ℃,mass space velocity of 1.0 h-1,hydrogen/hydrocarbon molar ratio of 5,catalyst mass of 1.0 g,cM/cA of 0.266 and n-heptane conversion rate of 70.75％,the total selectivity of isomers is 95.14％;the total yield is 67.31％,of which the yield of multi-branched isomers is 15.63％,and that of cracking products is less than 5％.
Beta zeoliteisomerizationPt contentn-heptanemetal centeracid center
NETL
NSTL
万方数据
