TITLE:
An Experimental Study of the Performance of Isomorphically Zirconium-Substituted Mesoporous Alumina Supported Cobalt Catalysts in Fischer-Tropsch Synthesis
AUTHORS:
Sabar Simanungkalit, Mingming Zhu, Gia Hung Pham, Zhezi Zhang, Dongke Zhang
KEYWORDS:
Cobalt Catalyst, Fischer-Tropsch Synthesis, Isomorphic Substitution, Mesoporous Alumina, Zirconium
JOURNAL NAME:
Advances in Chemical Engineering and Science,
Vol.12 No.1,
January
13,
2022
ABSTRACT: A series
of mesoporous alumina (MA) supported cobalt (Co/MA) catalysts with MA
isomorphically substituted by zirconium (Zr) were synthesised and evaluated for
their performance in the Fischer-Tropsch
synthesis. The Zr/(Zr + Al) atomic ratios varied from 1% - 15%. A
zirconium-impregnated Co/MA catalyst prepared by wet impregnation with a Zr/(Zr
+ Al) atomic ratio of 5% was also evaluated to examine Zr incorporation’s
effect method. The catalysts synthesised were characterised using N2 adsorption-desorption, X-ray Powder Diffraction (XRD), Transmission Electron
Microscopy (TEM), and X-Ray Photoelectron Spectroscopy (XPS). It was found that
Zr4+ ions were incorporated into the framework of MA and kept intact
up to a Zr/(Zr + Al) atomic ratio of 5%. The cobalt dispersion and reducibility
were improved as the Zr/(Zr + Al) atomic ratio increased to 50%. The
performance of these catalysts for Fischer-Tropsch
synthesis was evaluated using a fixed bed reactor at temperature and pressure
of 493 K and 20 bar, respectively. The feed syngas had an H2/CO ratio of 2, diluted with 10% Ar. For
isomorphically Zr-substituted Co/MA, the CO conversion and selectivity
of diesel (C10 - C20) increased first and then decreased with
increasing the Zr/(Zr + Al) atomic ratio. The maximum 38.9% CO conversion and
34.6% diesel (C10 - C20) selectivity were obtained at
Zr/(Zr + Al) atomic ratio of 5%. The isomorphic substitution method was better
than the wet impregnation method in CO conversion and diesel selectivity.