A kind of ethylene selective hydrogenation refining method

Abstract

The invention relates to an ethylene selective hydro-refining method. A thermal insulation bed reactor for hydrogenation is arranged after an ethylene rectifying tower and before an ethylene polymerization reactor. A Pd-Pb catalyst is filled into a fixed bed reactor, and the carrier of the catalyst is an alumina carrier. During the preparation process of the catalyst, the alumina carrier is combined with hydroxyl containing bipyridine derivatives; then the hydroxyl containing bipyridine derivatives and active components can form metal complexes; the activity and selectivity of hydrogenation reactions of the provided method are far more better than those of hydrogenation reactions of conventional methods; the ethylene purity is improved, and thus the performance of polymerized ethylene products is well improved. At the same time, the green oil is reduced, so the active center of catalyst is not covered by the byproducts, the activity and selectivity of catalyst are well preserved, and the service life of catalyst is prolonged. Even if the hydrogenation raw materials contain a certain amount of C4 fraction, the catalyst still has an excellent hydrogenation performance.

Description

Technical field [0001] The invention relates to a selective hydrogenation method, in particular to a selective hydrogenation refining method of ethylene. Background technique [0002] Polymer grade ethylene production 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 meets the standard, the selectivity of the catalyst is excellent, which can make ethylene generate as little ethane as possible, which is helpful for improving the entire process. The ethylene yield of the process is of great significance to improve the economic efficiency of the device. [0003] The pyrolysis C2 fraction contains 0.5%-2.5% mole fraction of acetylene. When producing polyethylene, a s...

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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

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