Environmental Engineering Reference
In-Depth Information
Figure 6.17: Effect of regeneration temperature on active metal content of catalyst [From
ref.
401
. Reprinted with permission].
6.2.4.1 Surface Properties
Surface properties such as surface area as well as pore volume and pore size distribution can
be influenced by the regeneration conditions. According to
Fig. 6.18 [401]
, the optimum of the
surface area and pore volume recovery can be achieved at about 400
◦
C. At the optimum, a
complete recovery of surface area was achieved, whereas the recovery of pore volume
approached 80% of the fresh catalyst (
Table 6.4
)
[401]
. These results were obtained by a
careful regeneration conducted in steps, i.e., in 5% O
2
, followed by the final burn-off in air.
Below 400
◦
C, the surface properties were not fully developed because of the burn-off of coke
Table 6.4: Properties of fresh and spent catalysts [From ref.
401
. Reprinted with permission].
Fresh
Spent
MoO
3
15
.
7
15
.
1
CoO
4
.
1
4
.
0
Carbon
10
.
5
Sulfur
6
.
4
Surface area (m
2
/g)
240
108
Pore volume (mL/g)
0
.
54
0
.
22
