球形SiO2模型催化剂的制备及在渣油扩散系数测定中的应用

 利用正硅酸乙酯水解缩合反应，制备了粒径为293nm的单分散二氧化硅球形颗粒。将二氧化硅悬浮液在重力场中沉降、干燥，在800℃煅烧后，得到直径为4mm的模型催化剂小球。根据模型催化剂和渣油的特点进行假设，通过物料衡算建立了球形模型催化剂中的扩散数学模型，经Laplace变换求得解析解，模型简单，求解容易。采用大港减压渣油抽提油，以球形模型催化剂进行扩散实验，根据模型求解，得到大港7＃抽提油在模型催化剂中的有效扩散系数为1.72×10-10 m2/s，结果准确可靠。

PREPARATION OF SiO2 MODEL CATALYST AND ITS APPLICATION IN THE MEASUREMENT OF DIFFUSION COEFFICIENT OF PETROLEUM RESIDUE

Spherical Model catalysts of 4 mm were prepared by firstly ordered packing of monodisperse 293 nm silica spheres, which were prepared through hydrolysis and condensation of alkoxysilanes, and then calcining at 800℃. Based on the characteristics of the model catalyst and residue oil, some assumptions were made, and the mathematical model of oil diffusing in the spherical model catalyst was established according to material balance. Through Laplace transform an analytical solution of the model was found. The established model is simple and the solution is convenient. Using the spherical model catalyst prepared the diffusion coefficient of a fraction of Dagang residue oil was determined and founded to be 1.72×10-10 m2/s.