柠檬酸改性制备NiCu/SAPO-11催化剂及其加氢性能

Preparation of NiCu/SAPO-11 by citric-acid modification and its hydrogenation performance

为了研究柠檬酸对NiCu/SAPO-11催化剂的结构和临氢异构性能影响,通过柠檬酸改性制备一系列的NiCu/SAPO-11催化剂。采用X射线衍射(XRD)、N2吸附-脱附、NH_(3)程序升温脱附(NH_(3)-TPD)、透射电子显微镜(TEM)和氢气程序升温还原(H2-TPR)等技术对催化剂进行表征。以正十六烷(n-C16)为模型化合物,研究催化剂在固定床反应器中的临氢异构性能。结果表明,柠檬酸改性可以增强金属的分散性,可以使催化剂具有更大的比表面积和孔体积,暴露出更多的酸性位点,从而增加催化剂的催化活性。在温度为340℃、空速为1.5 h-1、压力为1.5 MPa、氢气和n-C16体积比V(H2):V(n-C16)为1 000的条件下,正十六烷的转化率,异构十六烷(i-C16)的选择性和收率分别为95.67%,94.89%和90.78%。

A series of NiCu/SAPO-11 catalysts were prepared by citric acid modification and the effect of citric acid on the structure and hydroisomerization performance of catalysts was investigated. The catalysts were characterized by X-ray diffraction(XRD), N2 adsorption-desorption, NH_(3) temperature-programmed desorption(NH_(3)-TPD), transmission electron microscopy(TEM) and H_(2) temperature-programmed reduction(H_(2)-TPR).The hydroisomerization performance of catalysts was studied with n-hexadecane as model compound in a fixed bed reactor. The results show that citric acid modification enhanced the dispersibility of metals, increased the specific surface area and pore volume of the catalysts, and promoted the exposure of acid sites, thereby improving the catalytic activity of catalysts. The conversion of hexadecane, the selectivity and yield of iso-hexadecane reached 95.67%, 94.89% and 90.78%, respectively under 340 ℃, 1.5 MPa, WHSV(weight hourly space velocity) of 1.5 h-1 and H2/n-C16 volume ratio of 1 000.