Application of a silicalite-1 membrane reactor in metathesis reactions

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• 作者：van de Graaf ; Jolinde M. ; Zwiep ; Marco ; Kapteijn ; Freek ; Moulijn ; Jacob A.
• 关键词：Membrane reactor ; Zeolite membrane ; Silicalite-1 ; Metathesis ; Propene ; Equilibrium limited reaction ; Product removal
• 刊名：Applied Catalysis A: General
• 出版年：1999
• 出版时间：March 22, 1999
• 年：1999
• 卷：178
• 期：2
• 页码：225-241
• 全文大小：461 K

文摘

A silicalite-1 membrane was used in a membrane enclosed catalytic reactor to study the effect of selective product removal in the equilibrium limited metathesis of propene to ethene and 2-butene and of cis-2-butene to trans-2-butene. Based on a simple model of the membrane reactor, the goals for membrane performance, in terms of permeability and selectivity, were predetermined.

The metathesis reactions were carried out at 296 K using a 16.4 wt % Re₂O₇/γ-Al₂O₃ catalyst, which was activated ex situ using tetraethyltin as a promoter. The membrane was able to separate trans-2-butene from propene (α_C4/C3=5) and from cis-2-butene (α_trans/cis=1.6). In both reactions trans-2-butene is a product, so the effect of product removal on the conversion could be studied.

Depending on the operating conditions, the propene conversion was 13 % higher than the thermodynamic equilibrium conversion obtained in a conventional packed bed reactor. The ratio between trans-2-butene and cis-2-butene formed, increased with 34 % compared to the thermodynamic equilibrium. The trans-2-butene yield from the geometrical isomerization of cis-2-butene increased with 4 % compared to the thermodynamic equilibrium.

Comparison of the areal time yield of the silicalite-1 membrane with the space time yield of catalytic reactors revealed that the current permeability of the membrane is not far from realistic for industrial application.