Vr. Choudhary et al., Steam and oxysteam reforming of methane to syngas over CoxNi1-xO supportedon MgO precoated SA-5205, AICHE J, 47(7), 2001, pp. 1632-1638
Catalytic steam and oxysteam reforming of methane to syngas studied involve
s coupling of exothermic oxidative conversion and endothermic steam-reformi
ng processes over CoxNi1-xO (x = 0.0 - 0.5) supported on MgO precoated comm
ercial low surface area ( < 0.01 mZ g(-1)) macroporous silica-alumina SA-52
05 catalyst carrier The influence of the Co/Ni ratio of the catalyst on its
performance in steam and oxysteam reforming processes (at 800 and 850 degr
eesC) was studied For the steam reforming process, the Co/Ni ratio influenc
es strongly on the methane and steam conversion and CO selectivity and prod
uct H-2/CO ratio, particularly at lower temperature. When the Co/Ni ratio i
s increased, the methane and H2O conversion and CO selectivity are decrease
d markedly. For the oxysteam reforming process, the influence of the Co/Ni
ratio on the performance is smaller and depends on process conditions. When
the Co/Ni is increased, the methane conversion passes through a maximum at
the Co/Ni ratio of 0.17 The influence of the reaction temperature (800 and
850 degreesC) and CH4/O-2 and CH4/H2O ratios on the conversion, selectivit
y, H-2/CO product ratio, and net reaction heat (DeltaH(r)) was studied in t
he oxysteam reforming (at space velocity of 47, 000 cm(3 .) g (- 1 .) h (-
1)) over the catalyst with an optimum Co/Ni ratio (0.17) and a higher Co/Ni
ratio (1.0). The oxysteam reforming process involves coupling the exotherm
ic oxidative conversion of methane and the endothermic methane steam reform
ing reactions, making the process highly energy-efficient and nonhazardous.
This process can he made thermoneutral, mildly exothermic, and mildly endo
thermic by manipulating process conditions.