Upgrading of an Australian coal-derived liquid. 2. Characterisation of Ni-Mo/Al 2O 3 catalysts

Abstract

A suite of ten Ni-Mo/Al 2O 3 catalysts of varying active species loadings, previously tested for their ability to upgrade an Australian coal-derived liquid, were characterised by a range of techniques. This included surface area and porosity measurements, XRD, TPR and acidity analysis. The coke deposition during upgrading was also measured by TGA. It was found that those catalysts of highest initial activity with regards to phenol removal and aromatic hydrogenation (1.9 wt% Ni/7.9 wt% Mo to 3.7 wt% Ni/15.1 wt% Mo) had high surface areas (> 170 m 2/ g) and pore radii of near 50 Å, were amorphous in character, possessed both metal-support and metal-metal interactions and had intermediate acid site densities. These catalysts were also found to undergo more rapid coke deposition, with coke levels of up to 11% by weight of the spent catalyst being found, resulting in a loss of surface area and porosity. It has been previously argued that the catalysts of highest initial activity possess an optimum active phase dispersion on the alumina support. Evidence from a number of techniques was found to indicate that the catalysts of low loadings (below 3.7 wt% Ni/15.1 wt% Mo) had well dispersed active phase.