Optimized diesel hydrocracking catalyst and preparation method thereof

Abstract

The invention discloses an optimized diesel hydrocracking catalyst and a preparation method thereof. The optimized diesel hydrocracking catalyst is prepared from the following raw materials in percentage by weight: 1 to 25 percent of a modified molecular sieve, 10 to 65 percent of gamma-Al2O3, 15 to 70 percent of amorphous silica-alumina, 9 to 40 percent of an adhesive and 10 to 35 percent of active metal oxide. The catalyst has a specific surface area of 200 to 400m<2>/g and a total pore volume of 0.30 to 0.65cm<3>/g. The catalyst is obtained by adding the modified molecular sieve into an inorganic aluminum salt solution for preparing the gamma-Al2O3, performing precipitation, drying and calcination to obtain a composite material of the molecular sieve and the gamma-Al2O3, and performing mixing, rolling, forming, drying and activating on the other materials and the composite material according to the material proportion of the catalyst. The molecular sieve in a catalyst carrier of the catalyst is high in silica-alumina ratio, high in dispersity in the carrier and large in specific surface area, so that the carrier has more uniform acidic sites; alumina makes contact with the molecular sieve more closely, so that the condensation point of a diesel distillate can be obviously reduced and the cetane number of diesel can be increased on the premise of ensuring high yield of the diesel.

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...

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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.

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