New Catalysts from Spent Catalysts - Spent Hydroprocessing Catalysts - page 236

Figure 9.3: Effect of spent catalyst content on surface area and pore volume [From ref. 9 .
Reprinted with permission].
Table 9.1 [522] , adding 20 wt.% of the coked and decoked catalyst to boehmite would result in
the addition of about 1.3 and 1.7 wt.% of Mo, respectively. Then, the differences between the
coked and decoked catalysts in HDS and HDV activities shown in Fig. 9.4 are expected to be
smaller when the conversions are correlated with the content of Mo in reprocessed catalyst.
This is indeed shown in Figs 9.5 and 9.6 [522] where the HDS and HDV conversions were
correlated with the actual amount of Mo in the catalysts rather than the amount of spent
catalysts added to boehmite. In fact, Figs 9.5 and 9.6 suggest that for most part, the differences
between the coked and decoked catalysts are much less evident compared with Fig. 9.4
[522,523] . Then, it is the amount of active metals which dominated the activity of reprocessed
catalysts.