Catalysts preparation
The catalyst was prepared by impregnation in excess dissolution
method. A one step impregnation method was used to
deposit the active phase and promoter on aluminium oxide
(Sasol Disperal). The nominal composition of the active phase
was 5%wt Ni and 3%wt Co. Aqueous solutions of
Ni(NO3)2$6H2O, Co(NO3)2$6H2O, La(NO3)2$6H2O (Panreac) were
used as precursor salts respectively. An excess of aqueous
solution of metal precursor salts was added to alumina oxide
powder, calcined previously at 800 C for 4 h, in a rotary vacuum
evaporation system. After impregnation, the catalyst
was dried in air (110 C, 12 h) and then calcined at 800 C for 4 h
in order to remove precursor salts and to stabilize the active
phase, trying to avoid active phase sintering due to the increase
of temperature and loss of surface area in reaction
conditions. The aim is to stabilize the catalyst texture prior to
reaction trying to avoid or to minimize surface area loss in
reaction conditions that could produce changes in catalyst
activity and stability.