Issue 11, 2014

Hydroisomerization of long-chain paraffins over nano-sized bimetallic Pt–Pd/H-beta catalysts

Abstract

The hydroisomerization of long-chain n-paraffins was studied in the temperature range of 205–230 °C at pH2 = 50 bar using a pilot-scale trickle-bed continuous-flow reactor over bimetallic catalysts consisting of mixtures of platinum and palladium supported on commercially available nano-sized zeolite beta (nSi/nAl = 12.5 and 25, respectively) extruded with an alumina binder. For n-hexadecane conversion, high yields of isomers (25 and 45 wt.% of mono- and multibranched isomers, respectively) without extensive cracking (>10 wt.%) were obtained at a conversion of 80%. Long-term tests with n-hexadecane and blends of solid n-paraffins for 30–60 days on-stream clearly indicate that a minor loss in catalyst activity can easily be compensated for by increasing the reaction temperature from 220 °C to 225 °C. The zeolite with a “mild acidity” exhibits a low hydrocracking activity with isomerization yields of up to 70 wt.% and high stability over more than 60 days on-stream. Carbonaceous deposits formed during n-paraffin hydroisomerization were investigated by elemental analysis, TGA, ATR-FTIR and 13C MAS NMR spectroscopy, showing the formation of hydrogen-rich coke which leads to pore blocking.

Graphical abstract: Hydroisomerization of long-chain paraffins over nano-sized bimetallic Pt–Pd/H-beta catalysts

Article information

Article type
Paper
Submitted
30 Apr 2014
Accepted
09 Jul 2014
First published
10 Jul 2014
This article is Open Access
Creative Commons BY-NC license

Catal. Sci. Technol., 2014,4, 4045-4054

Author version available

Hydroisomerization of long-chain paraffins over nano-sized bimetallic Pt–Pd/H-beta catalysts

F. Bauer, K. Ficht, M. Bertmer, W. Einicke, T. Kuchling and R. Gläser, Catal. Sci. Technol., 2014, 4, 4045 DOI: 10.1039/C4CY00561A

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