Engineering and Technology Journal

Hydroisomerization of n-Heptane in a Fixed-Bed Reactor Using a Synthesized Bimetallic Type-HY Zeolite Catalyst

Document Type : Research Paper

Authors

1 Chemical Engineering Department, University of Technology-Iraq

2 Chemical Engineering Department, University of Technology - Iraq

Abstract

The synthesis of NaY-zeolite was performed hydrothermally. The preparation of the bifunctional catalysts was achieved by loading NH4Y-zeolite with a cheap Zr metal, as a second loading metal, with tiny amounts of Pt to compose a Pt-Zr/Y-zeolite catalyst. Different characterization methods (i.e., XRD, SEM, EDX, BET, and AFM) were used to investigate the catalyst properties. The catalytic performance was studied by performing the hydroisomerization of n-heptane in a gas phase at a temperature of 275°C and atmospheric pressure in a fixed-bed reactor. The GC-FID results of the products confirmed the positive role of Zr in enhancing the catalytic features, as reflected by the increase in the isomerized products and the decrease in the unwanted by-products. Incorporating 1.0wt%Zr with 1.0wt% of Pt significantly improved the activity and selectivity and increased the yield of branched alkanes. This was achieved because the addition of zirconium provided an extraordinary Lewis acidity to the zeolite-framework structure and simultaneously took advantage of the electronic and catalytic properties of Zr and Pt metals to enhance its novel catalytic features. This reduced the amount of Pt metal and halved the cost of the catalyst. In addition, the bimetallic catalyst (HY-zeolite loaded with 1wt%Pt & 1wt%Zr) achieved values of 74.2, 78.8, and 58.5mol% for conversion, selectivity, and yield, respectively. The conversion was improved to a level close to 2wt% Pt/HY-zeolite catalyst, while selectivity was not significantly decreased from that of 2wt% Zr/HY-zeolite catalyst, reaching a yield level of isomers close to that of 2wt% Pt/HY-zeolite catalysts.

Graphical Abstract

Highlights

  • The synthesis of NaY-zeolite by the hydrothermal method.
  • Modification of NaY to form NH4Y, HY, and Metal-Loaded-HY-Zeolites by incipient wetness impregnation method
  • The preparation of the bimetallic catalyst depends on the two metals Zr and Pt.
  • Performing the hydroisomerization of n-heptane and proving the novel catalyst (1wt% Pt with 1wt% Zr)/ HY-Zeolite is an active and selective catalyst.
  • The amount of the costly Pt metal in the catalyst depends on the cheap Zr Metal was decreased.

Keywords

Main Subjects

References
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Engineering and Technology Journal
Volume 40, Issue 9
Chemical Engineering
, 12 Articles
September 2022
Page 1158-1170
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