II International Symposium on Carbon for Catalysis ABSTRACTS

PP-I-33
consistence of the process, and the recovering in the surface area, which is one of the most
important factors affecting the activity of these catalysts.
The regeneration tests have been carried out in a bench scale fluidized bed reactor. The
following activation conditions have been studied: (1) activating agent: CO 2 (2) activation
temperature: 900, 925 and 950º C; (3) carbon residence time: 2 and 4 hours.
Table 1 shows the results obtained
Catalyst Burn off (%) BET Area (m 2 /g)
CG Norit fresh - 1300
for the Activated Carbon-CG
CG Norit deactivated - 111 NORIT. A lineal relationship
CG Norit regenerated
CG Norit regenerated
CG Norit regenerated
925ºC 2 hours 30 1287
900ºC 2 hours
900ºC 4 hours
CG Norit regenerated
5
15
303,6
606,4
925ºC 4 hours 57 1860
between % of weight loss (% of
burn off) and surface area can be
observed. A compromise between
% burn off and surface area
recovered must be accomplished in
order to assure that the process is self-consistent. For this reason, the optimum regeneration
conditions selected were 900ºC- 4 hours and 925ºC- 2 hours. In both conditions, the weight
loss is under 30%, taking into account that after each reaction step, 400mg/g carbon is
deposited, which corresponds to a 40% of the catalyst mass. The recovering of the surface
area is over 50% in both conditions.
% H2
% H2
100
80
60
40
20
REGENERATION
REGENERATION
925ºC, , 2 hours
REGENERATION
1 st CYCLE 2 nd CYCLE 3 th CYCLE
0
0 4 900ºC, 8 412hours
16 20 24
time [h]
900ºC, 4 hours
100
80
60
40
20
0
REGENERATION
ERATION
REGENERATION
1 st CYCLE 2 nd CYCLE 3 th CYCLE
REGEN
REGENER
0 4 8 12 16 20 24
time [h]
Several cycles consisting in series of
reaction with CH 4 and regeneration with
CO 2 have been performanced for both
selected conditions. As is shown in figure 1,
the recovery of the activity for the CG Norit
regenerated at 925ºC-2h. is achieved almost
completely after three successive reaction–
regeneration cycles, while at 900ºC-4h. the
catalyst regeneration is not feasible after the
second cycle.
Further work is being carried out in order to
gain knowledge about the mechanisms of
the regeneration process.
References
1 N. M. Muradov. Catalysis Communications 2 (2001) 89-94
2 R. Moliner, I. Suelves, M.J. Lázaro, O. Moreno. Int. J. of Hydrogen Energy 30 (2005)
293-300
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