Optimized diesel hydrocracking catalyst and preparation method thereof

Abstract

An optimized diesel hydrocracking catalyst and a method for preparing same. Raw materials comprise the following components in percentage by weight: 1-25% of modified molecular sieve, 10-65% of γ-Al2O3, 15-70% of amorphous silica-alumina, 9-40% of binder, and 10-35% of active metal oxide. The specific surface area of the catalyst is 200-450 m2 / g, and the total pore volume is 0.30-0.65 cm3 / g. To obtain a carrier, a modified molecular sieve is added to an inorganic aluminum salt solution used for preparing γ-Al2O3, and precipitation, drying, and roasting are performed to obtain a composite of molecular sieve and γ-Al2O3; then the remaining materials are mixed with the composite according to the material proportion of the catalyst, and rolling, forming, drying, and activation are performed to obtain the catalyst. The molecular sieve in the catalyst carrier has a high silica / alumina ratio and high specific surface area, and is highly dispersed in the carrier; thus, the carrier has more uniform acid sites, and alumina is in closer contact with the molecular sieve; and therefore, the catalyst can remarkably reduce the pour point of a diesel fraction and improve the cetane number of diesel while guaranteeing a high diesel yield.

Description

technical field [0001] The invention relates to a catalyst, in particular to an optimized diesel hydrocracking catalyst and a preparation method thereof. Background technique [0002] Hydrocracking is a very important technology for the efficient conversion of heavy oil and the production of clean oil products in the oil refining industry. It can process heavy crude oil with high sulfur and high metals. It has a wide source of raw materials, high production flexibility, good product quality and middle distillate Features such as high oil yield. Hydrocracking technology can directly produce low-aromatic, low-sulfur and low-nitrogen high-quality middle distillate products from vacuum diesel oil (VGO), which can meet increasingly stringent environmental protection requirements, and the catalyst plays a central role in the hydrocracking reaction. The key to hydrocracking technology lies in the development and improvement of catalysts. [0003] The conventional preparation meth...

AI Technical Summary

Problems solved by technology

[0004] However, in the hydrocracking catalyst prepared by the existing method, the components are simply mechanically mixed, and the components in the catalyst are easily agglomerated into secondary particles, which makes the dispersion of the active component poor, and the prepared catalyst is difficult to Play the best performance, but also have the problem of complicated preparation process and high cost

For example: CN98114489.6 discloses a hydrocracking catalyst, amorphous silica-alumina and Y-type molecular sieve are used as cracking components, and metal oxides of Group VIB and Group VIII are hydrogenation components, and a series of hydrocracking is adopted Production of middle distillate oil, the catalyst has good nitrogen resistance, but its preparation method is relatively complicated and the preparation cost is relatively high

CN139352IA discloses a medium-oil type hydrocracking catalyst and its preparation method. The carrier used in the catalyst is amorphous silica-alumina, alumina and composite molecular sieves of Y and β, wherein the composite molecular sieve is obtained by burning the former powder of β molecular sieve to remove the template agent. After mixing with modified Y molecular sieve, it is obtained by ammonium exchange treatment. The catalytic activity of this catalyst is not high, and the product quality of middle distillates of jet fuel and diesel oil is average, which needs to be further improved.

Images