Comparison of MoS₂ Catalysts Prepared from Mo-Micelle and Mo-Octoate Precursors for Hydroconversion of Cold Lake Vacuum Residue: Catalyst Activity, Coke Properties and Catalyst Recycle

Abstract

The hydroconversion of cold lake vacuum residue (CLVR) in a semibatch, slurry-phase reactor was studied at 415–445 °C, 13.8 MPa, and a reaction time of 1 h, using MoS2 catalysts prepared from Mo-octoate and Mo-micelle precursors. Both precursors yielded MoS2 with the same activity in terms of coke suppression, residue conversion, and hydrogen uptake. The coke yield decreased from 22 wt % in the absence of a catalyst, to 4.8 wt % in the presence of 100 ppm Mo. A Mo concentration of 600 ppm was found to be optimum in terms of maximizing the residue conversion (84 wt %) and minimizing the coke yield (2.9 wt %). The characteristics of the recovered coke as a function of catalyst concentration and age in the reactor were also investigated. At high catalyst concentrations (>600 ppm Mo) and short reaction times, the generated coke was relatively amorphous, with a high H/C ratio. The solid catalyst–coke recovered from the reactor was recycled without further treatment. The catalytic activity of the recycled catalyst was the same as the fresh catalyst, and no catalyst deactivation was observed under the hydroconversion conditions of the present study.

Catalyst Deactivation in Slurry-Phase Residue Hydroconversion

“…When a higher concentration of catalyst was used in the reactor, a more hydrogenated coke was produced because of the increased extent of the hydrogenation reactions. 23 Figure 4 shows that the H/C atom ratio of the coke recovered from the experiment in which 600 ppm Mo (derived from the Mo-micelle precursor) was used was high and similar to the H/C atom ratio of the coke recovered from the experiment in which 1800 ppm Mo (derived from Mo− octoate) was used. This is due to the formation of NH 4 Cl during the synthesis of the Mo−micelle precursor that is captured by the coke.…”

“…Details of the Mo−micelle precursor preparation have been reported previously. 21,23 A semi-batch reactor with a volume of 250 mL (Parr Instruments Company) was used to assess the catalytic activity of the fresh and recycled catalysts. Approximately 80 g of Cold Lake vacuum residue (CLVR, provided by Imperial Oil) was used as the feed for each of the hydroconversion experiments.…”

Promotion effects with dispersed catalysts for residue slurry hydroconversion

“…This limitation of conversion is probably due to H 2 transfer limitations in the batch reactor, as it was observed in the literature [24,25]. The evolution of pressure during the experiments allows a straightforward evaluation of the performance of individual metals and their mixtures.…”

Slurry-Phase Batch Microreactor for Hydroconversion Studies

“…1,4 Slurry-phase hydroconversion reactors operating with unsupported metal sulphide catalysts (such as MoS 2 ) 2,4-7 are effective in this role, resulting in high feedstock conversions (>80 wt%), liquid yields (>90 wt%) and heteroatom removal (>35 wt% S), with low coke (<6 wt%) and gas (<2 wt%) yields. 1,4,5, [7][8][9][10][11][12][13][14] Slurry-phase reaction systems are also effective in the upgrading of fast pyrolysis oil 15 with the high oxygen (>45 wt%) content of bio-oils resulting in a low heating value (approximately 18 MJ/kg), high viscosity (which may range from 100 cPs to over 100,000 cPs) and poor stability 16,17 . Catalytic hydrodeoxygenation (HDO) may be employed to reduce the oxygen content of bio-oils 15,16,18 .…”

“…For TEM analyses, the solid was sonicated in ethanol (Cole-Parmer Ultrasonic Cleaner, model number 08895-12, 100 W operating at 42 kHz) for approximately 10 s to form a translucent grey suspension. A single drop of this suspension was applied to a copper grid and allowed to dry before analysis.The activity of the MoS 2 catalyst measured in the micro-reactor is compared to that obtained using a conventional 250 mL stirred autoclave batch reactor, as presented previously6,14,15 .…”