Selective hydrogenation catalyst for improving coking resistance

Abstract

The invention discloses a selective hydrogenation catalyst for improving coking resistance. Carriers of the selective hydrogenation catalyst mainly comprise alumina and have double-humped hole distributed structures. The selective hydrogenation catalyst contains 0.01-0.5wt% of Pd which is in a shell layer distribution form and has thickness of 1-500 microns, and 0.2-5wt% of Ni. Ni is mainly distributed in large holes of the carrier so that a catalyst surface coking degree is greatly reduced, the compound subjected to hydrogenation saturation is gradually diffused into catalyst channels, channel blocking is avoided and a catalyst service life is greatly prolonged. The selective hydrogenation catalyst is especially suitable for C2 and C3 fraction hydrogenation, obviously reduces a green oil yield and catalyst coking, prolongs a catalyst service life and improves device operation economic benefits.

Description

technical field [0001] The invention relates to a selective hydrogenation catalyst, in particular to a selective hydrogenation catalyst with high coking resistance. Background technique [0002] Ethylene obtained from steam cracking of petroleum hydrocarbons contains 0.5% to 2.3% acetylene by mass fraction. When used in polymerization, acetylene in ethylene will reduce the activity of the polymerization catalyst and affect the physical properties of the polymer, so it must be removed. At present, the selective hydrogenation method is commonly used in the industry to remove acetylene from ethylene, and the catalysts used are mainly noble metal catalysts such as Pd, Pt, and Au. In order to ensure that the ethylene generated by the hydrogenation of acetylene and the original ethylene in the raw material will not continue to be hydrogenated to ethane, resulting in the loss of ethylene, it is necessary to ensure a high hydrogenation selectivity of the catalyst in order to improv...

AI Technical Summary

Problems solved by technology

[0008] However, in the carbon two hydrogenation reaction, the generation of green oil and the coking of the catalyst are important factors affecting the reaction life of the catalyst. The activity, selectivity and service life of the catalyst constitute the overall performance of the catalyst. The above methods may be useful for improving catalyst activity, Selectivity proposes a better method, but it does not solve the problem that the catalyst is easy to coke, or it solves the problem that the catalyst is easy to generate green oil and coke, but it does not solve the problem of selectivity

Although the carrier with a macroporous structure can improve the selectivity, the larger molecules generated by the polymerization and chain growth reactions tend to accumulate in the macropores of the carrier, causing coking and deactivation of the catalyst and affecting the service life of the catalyst.

Images