Carbon distillate post-hydrogenation method

Abstract

The invention relates to a post-hydrogenation method of carbon distillates. The fixed-bed reactor used for hydrogenation is located behind the demethanizer, and the carbon distillate from the front deethanizer in the ethylene unit is pressurized and hydrogenated. Enter the adiabatic bed reactor for selective hydrogenation. The fixed bed reactor is equipped with a Pd-Ni catalyst. During the preparation process, the catalyst is combined with a bipyridine derivative with a hydroxyl group through an alumina carrier. Hydroxybipyridine forms a metal complex with the active component; the method of the present invention greatly improves the activity and selectivity of the hydrogenation reaction compared to the traditional hydrogenation method, and the amount of green oil generated during the hydrogenation process is also greatly reduced. At the same time, the reduction of green oil makes the active center of the catalyst not covered by by-products, and the catalyst activity and selectivity are well maintained; the catalyst used in the present invention has excellent anti-impurity interference ability, and is especially suitable for S, As C2 hydrogenation unit with high impurity content.

Description

technical field [0001] The invention relates to a selective hydrogenation method, in particular to a carbon-two selective hydrogenation method in a sequential separation process. Background technique [0002] The production of polymer grade ethylene is the leader of the petrochemical industry, and polymer grade ethylene and propylene are the most basic raw materials for downstream polymerization units. Among them, the selective hydrogenation of acetylene has an extremely important impact on the ethylene processing industry. In addition to ensuring that the acetylene content at the outlet of the hydrogenation reactor reaches the standard, the selectivity of the catalyst is excellent, which can make ethylene generate as little ethane as possible, which is beneficial to improving the entire process. It is of great significance to improve the ethylene yield of the process and improve the economic benefits of the device. [0003] The cracked carbon distillate contains acetylene ...

AI Technical Summary

Problems solved by technology

Using this patented method, the carrier adsorbs a specific polymer compound through the chemical adsorption of the hydroxyl group of alumina and the polymer, and the amount of the polymer compound adsorbed by the carrier will be limited by the number of hydroxyl groups of alumina; the functionalized polymer and Pd The complexation effect is not strong, and sometimes the loading capacity of the active components does not meet the requirements, and some active components remain in the impregnation solution, resulting in an increase in the cost of the catalyst; the preparation of carbon dioxide hydrogenation catalysts by this method also has the disadvantage of complicated process flow

[0024] In recent years, due to the poor quality of raw materials in some ethylene plants, their C2 selective hydrogenation units contain certain impurities such as As and S, and bimetallic supported catalysts with Pd as the active component and Ag as the promoter are used in this type of unit , As, S and other impurities affect the activity of the catalyst, and in severe cases, the catalyst will be deactivated, which will bring the risk of alkyne leakage in the device

Images