New Catalysts from Spent Catalysts - Spent Hydroprocessing Catalysts - page 241

Figure 9.7: Effect of V content of catalysts reprocessed from coked spent catalysts (a: catalyst A;
b: catalyst B; c: catalyst C) on hydrodesulfurization (HDS) activity at 370 and 390 C [From
ref. 522 . Reprinted with permission].
120 A. The performance of the catalyst for residual oil hydroprocessing was found to be
roughly equal to that of a commercial catalyst.
9.1.1.3 Effect of Hydrothermal Treatment on Reprocessed Catalysts
The activity of the reprocessed catalysts can be significantly enhanced by subjecting spent
hydroprocessing catalysts to hydrothermal treatment at 300 ◦ C for 2 h [524] . The pore volume
and pore size distribution of the spent catalysts before and after hydrothermal treatment are
compared in Fig. 9.9 . It is seen that the pore volume after hydrothermal treatment increased
from 0.24 to 0.48 mL/g, whereas surface area increased from 37 to 70 m 2 /g. The volume of
pores in the 100-2000 A diameter range increased from 0.16 to 0.38 mL/g, while the mesopore
volume in the 100-500 A increased from 0.12 to 0.24 mL/g.
A hydrothermally treated spent catalyst was used to prepare reprocessed catalysts using
boehmite in similar manner as described above ( Fig. 9.1 ), i.e., 20, 40, and 60 wt.% of the