通过调变SAPO-11的孔道和酸性制备高选择性加氢裂化/异构化催化剂  

Preparation of Highly Selective Hydrocracking/hydroisomerization Catalyst for n-Hexadecane by Tuning Porosity and Acidity of SAPO-11

作　　者：任申勇[1] 黄志岗 孙华阳 李晓倩 郭巧霞[1] 申宝剑[1] REN Shen-yong;HUANG Zhi-gang;SUN Hua-yang;LI Xiao-qian;GUO Qiao-xia;SHEN Bao-jian(State Key Laboratory of Heavy Oil Processing,The Key Laboratory of Catalysis of CNPC,College of Chemical Engineering and Environment,China University of Petroleum,Beijing 102249,China)

机构地区：[1]中国石油大学(北京)化学工程与环境学院重质油国家重点实验室,北京102249

出　　处：《分子催化》2022年第6期534-546,共13页Journal of Molecular Catalysis(China)

基　　金：国家自然科学基金创新研究群体科学基金(22021004)

摘　　要：为了制备一种高选择性生产生物航空煤油的加氢异构化/加氢裂化催化剂,分别研究了酸和碱改性对分子筛SAPO-11的结构性质和酸性质的影响.当采用适当的磷酸浓度(0.3 mol·L^(-1),样品X2)时,样品具有良好的结晶度(64%)、外比表面积(204 m^(2)·g^(-1))和介孔体积(0.412 cm^(3)·g^(-1)),且均远高于对比样品.而最佳氢氧化钠浓度(0.5 mol·L^(-1),样品Y4)也显示出样品良好的结晶度、外比表面积和介孔体积(分别为77%、169 m^(2)·g^(-1)、0.416 cm^(3)·g^(-1)).通过XRD、NH3-TPD、SEM和IR对催化剂进行了详细的表征.Py-IR分析结果表明,样品的Bro¨nsted酸位点经过磷酸修饰和碱修饰后转化为Lewis酸位点.采用正十六烷对催化剂的加氢裂化/异构化性能评价表明,磷酸改性和碱改性可以提高正十六烷的转化率和产物的异正比,原因是酸碱处理提供了优化的外比表面积、介孔度和酸性质.对于长链正构烷烃的催化反应而言,增加分子筛的介孔度,也就是增加了分子筛的外比表面积,这减少了传质阻力,有助于增加长链烷烃与活性催化位点接触的频率,从而显著提高了Pt/SAPO-11对正十六烷的加氢异构化/加氢裂化能力,提高了生物航空煤油组分的产率.A comparative study of acid and alkali modification on the textural and acid property of SAPO-11 was investigated,respectively.When appropriate phosphoric acid concentration(0.3 mol/L,sample X2)was employed,the sample gave good crystallinity(64%),external specific surfacearea(204 m^(2)·g^(-1)),and mesoporous volume(0.412cm^(3)·g^(-1))which were much higher than those of original sample.The optimum sodium hydroxide concentration(0.5 mol·L^(-1),sample Y4)also afforded good crystallinity,external specific surfacearea and mesoporous volume of the product(77%,169 m^(2)·g^(-1),and 0.416 cm^(3)·g^(-1),respectively).Catalysts were further characterized in detail by XRD,NH3-TPD,SEM and IR.The results of Py-IR analysis presented that the Bro¨nsted acid sites of the samples were transformed into Lewis acid sites after the phosphoric acid and alkali modification.The hydrocracking/hydroisomerization evaluation of catalysts for n-hexadecane showed that the conversion of n-hexadecane and product selectivity on the iso/n ratio could be improved after phosphoric acid modification and alkali modification.For the catalytic reaction of long-chain n-alkanes,increasing the mesoporosity of the molecular sievecould reduce the mass transfer resistance and increase the contact frequency between the long-chain alkane and the active catalytic site.The results demonstrated that the optimized external specific surface area,mesoporosity,and acid property provided by acid and alkali treatment could significantly enhance the ability of hydrocracking/hydroisomerization of Pt/SAPO-11toward n-hexadecane to give a high yield of aviation biokerosene components.

关 键 词：SAPO-11 改性 孔道性质 酸性质 加氢裂化/异构化 

分 类 号：TQ426[化学工程]