Research On The Preparation And Catalytic Performance Of Ni/DUSY Catalyst For N-Heptane Hydroisomerization

Ultra-stable Y zeolite(USY)is more excellent than Y type molecular sieve properties of molecular sieve,because of its high silica alumina ratio,better heat stability,and is widely used in petrochemical process,has wide application prospect.This article selects malic acid and tartaric acid as aluminum remover,will be treated as commercial USY zeolite was modified and get more abundant DUSY molecular sieve pore structure,and provide the right amount of acid center,make it more suitable for as a catalytic carrier of n-heptane isomerization catalyst,and the load on the DUSY molecular sieve metal nickel,providing metal,with bifunctional catalyst for synthesis of performance.Firstly,tartaric acid and malic acid as aluminum remover,respectively to investigate three kinds of modified conditions: acid concentration,modification temperature,modification time,combined with the modification of a series of characterization,DUSY molecular sieve to determine two kinds of optimum modification conditions of aluminium remover(acid concentration,time,temperature),malic acid modification conditions: the best concentration of 0.25 mol/L,the modification time is 4.5 h,the temperature is 85?,under the condition of the preparation of molecular sieve is DUSY-1,tartaric acid optimum modification conditions:concentration is 0.15 mol/L,the modification time is 4.5 h,the temperature is 90?,under the condition of the preparation of molecular sieve is DUSY-2,and comparison of USY from the aspects of structure and two kinds of acid modified molecular sieve(DUSY-1 and DUSY-2).The results show that the crystallization effect of DUSY-1 is better,the peak shape is more sharp,the pole is more abundant,and more suitable as the catalyst carrier.To its load x%nickel preparation Ni/DUSY-1(x for metal load,the value of 2,4,6,8,10,similarly hereinafter)catalysts,metal activity for modified molecular sieve(hydrogenation,dehydrogenation),and considering the amount of catalyst,roasting conditions(roasting temperature,roasting time),temperature conditions(reduction temperature,reaction temperature)and time conditions(reduction time,response time)and flow rate of hydrogen on x%-Ni/DUSY-1 n-heptane isomerization catalyst performance impact.Under the same conditions,x%-Ni/DUSY-2 and x%-Ni/USY catalyst were prepared,and the catalytic performance of three catalysts was compared with heptane isomerization.The results of performance evaluation showed that the and isomerization selectivity of x%-Ni/DUSY-1 catalyst were the highest.When the load is 6%,the conversion rate of6%-Ni/DUSY-1 catalyst was 57.2%,and isoheptane selectivity was up to 72.5%.The conversion rate of 6%-Ni/DUSY-2 catalyst was only 38.5%,and isoheptane selectivity was only 56.7%.The conversion rate of 6%-Ni/USY catalyst catalyst was 30.3% and the selectivity was 49.9%.Therefore,the catalyst catalyzed n-heptane isomerization of6%-Ni/DUSY-1 catalyzed by malic acid modified molecular sieve was the best.