Selective hydrogenation method of alkyne and dialkene in alkene stream

Abstract

The invention provides a selective hydrogenation method of alkyne and dialkene in an alkene stream. The method comprises the steps that: an alkene stream containing alkyne and/or dialkene, and hydrogen are delivered into a hydrogenation reactor provided with a supported palladium catalyst; alkyne and/or dialkene in the alkene stream are hydrogenated into alkene under conditions of: a temperature in of 10 to 80 DEG C, a molar ratio of hydrogen to a total amount of alkyne and dialkene of 1 to 10, and a reaction pressure of 0.1 to 4 Mpa, such that alkyne and/or dialkene in the alkene stream are removed. The supported palladium catalyst comprises a carrier, palladium and optional modifying components. With a carbon monoxide adsorption in situ infrared spectroscopy method, the catalyst is tested under a temperature of 40 DEG C. In an obtained infrared spectrogram, an area ratio of an overhead absorption peak at a location of 1983 to 1990cm-1 to that at the location of 1870 to 1930cm-1 is lower than 0.2, and preferably 0.15. The method provides a high selectivity in the selective hydrogenation of alkyne and dialkene. The method can operate for a long period.

Description

technical field [0001] The present invention relates to a process for selective hydrogenation and, more particularly, to a process for the selective hydrogenation of alkynes and diolefins in olefin streams. Background technique [0002] Ethylene, propylene, butene and other products produced during steam cracking, catalytic cracking or thermal cracking contain a small amount of alkynes or dienes, and these impurities are harmful to subsequent polymerization and other reactions. Their presence not only degrades polymer properties, but can also lead to an explosion hazard. Selective catalytic hydrogenation is usually used in which the concentration of alkynes and diolefins is removed to very low levels (mol fraction < 1 x 10 -6 ) to obtain polymer-grade products; at the same time, it can also increase the output of monoolefins and improve resource utilization. In the C4 fraction, the butadiene-rich fraction is sometimes subjected to selective hydroremoval of alkynes to ob...

AI Technical Summary

Problems solved by technology

Due to the need to include specific Pd precursors or crystal form control agents in the preparation process, the composition of the catalyst becomes complicated and the preparation process is more cumbersome

In addition, the adsorption capacity of the reactants on the surface of the catalyst noble metal is an important factor affecting its activity and selectivity, which has not been reflected in the existing literature.

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