Alkyne selective hydrogenation catalyst and preparation method and applications thereof

Abstract

The invention belongs to the technical field of petrochemical engineering, and specifically relates to an alkyne selective hydrogenation catalyst and a preparation method and applications thereof. Thecatalyst is composed of an active component, a co-catalyst component, and a carrier. The active component is palladium. The co-catalyst component is added into the catalyst in different modes so as to enhance the hydrogenation stability and selectivity, reasonably adjust the acidity of the catalyst surface, promote the dispersion of active component (palladium), and create more active sites. Thecatalyst is applied to the selective hydrogenation of alkyne containing materials, in particular, C4 materials, which have a high alkyne content and are discharged from a butadiene extraction device.Vinyl acetylene and ethyl acetylene are converted into butadiene and butylene. The hydrogenation products are returned to a raw material storage tank or a butadiene extraction device to recover butadiene and butylene. The catalyst has the advantages that the hydrogenation conditions are mild, the activity and selectivity are high, the stability is good, and the operation period is long, and the catalyst is suitable for hydrogenation of materials with a high alkyne content.

Description

technical field [0001] The invention belongs to the technical field of petrochemical industry, and in particular relates to an alkyne hydrogenation selective catalyst and its preparation method and application. Background technique [0002] Butadiene is an important petrochemical basic organic raw material and synthetic rubber monomer. It is one of the most important components in the C4 fraction, and its position in petrochemical olefin raw materials is second only to ethylene and propylene. The main source of butadiene is the mixed carbon four produced by the ethylene plant as raw material, which is separated by solvent extraction. The mixed carbon four fraction produced by ethylene plant usually contains 40wt%~60wt% butadiene, 0.5wt%~2.0wt% alkyne, mainly including methylacetylene (MA), ethylacetylene (EA) and vinyl Acetylene (VA), others butanes (n-butane and isobutane) and butenes (n-butene, isobutene, trans-butene-2 ​​and cis-butene-2). [0003] At present, acetonitr...

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Problems solved by technology

[0015] Coking is another important cause of catalyst deactivation. The main reasons for coking are firstly poor catalyst selectivity, too many side reactions such as alkyne and diene polymerization, and secondly, too high reaction temperature or adiabatic temperature rise Too high, resulting in intensified polymerization of unsaturated hydrocarbons at high temperature

Once the colloid is formed, it will cover the active center or block the pores of the catalyst, thereby reducing the activity, selectivity and stability of the catalyst, and eventually causing the catalyst to be deactivated and unable to operate normally

[0016] In the prior art, catalysts with palladium as the active component are easily interfered by impurities such as water, solvents, and heavy components in the hydrogenation material, so the hydrogenation activity, especially the operation stability, is poor. In order to improve this situation, different A variety of additives to promote the dispersion of palladium and produce a synergistic effect with palladium to improve catalyst selectivity and stability

In the prior art, when the carrier is impregnated with the soluble salt of the auxiliary agent, due to the inhomogeneity of the pore structure of the carrier itself and the difficulty in achieving the consistency of the impregnation condition control, the auxiliary agent presents a non-uniform distribution in the catalyst, which is different from that of palladium. The synergistic effect is not fully exerted, which makes it difficult to achieve a balance between the hydrogenation activity, selectivity and stability of the catalyst

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