Table 15 Effect of rare
earth exchange of Y zeolite
on activity and selectivity
Rare earth on zeolite
0
4
8
16
Activity (C/(100-C))
2.55
2.8
3.0
4.0
Conversion
71.8
73.7
75
80
Coke
2.55
3.5
4.8
6.1
C 3 =/TC 3
0.81
0.75
0.72
0.65
C 4 =/TC 4
0.39
0.32
0.29
0.23
24.66
10
20
SiO 2 /AL 3 O 3 MOL RATIO IN UNIT CELL
% DEALUMINATION (STARTING WITH 5.0 SiO 2 /A L2 O 3 )
30
30
0
40
50
50
60
60
80
85
90
70
24.70
24.60
24.50
24.40
Unit Cell Size (a
o ) of Nay Zeoliete
24.30
24.20
24.52 (US-Y)
SODIUM-Y TYPE
Fig. 26 Unit cell size versus SiO 2 /Al 2 O 3 ratio for NaY zeolite
24.25
H-US-Y
RE-US-Y
RE-H-Y
CREY
H ea t of R ea ct io n
Sp ec ific Ca ta lys t Ac tiv ity
De lta Co ke
Oc tan e
Ac tiva tion En erg y
24.30
24.35
24.40
24.45
Fig. 27 Effect of unit cell size on catalytic properties
296
W. Letzsch