The decomposition of CH4 into C and H2 over Ni/SiO2 was investigated with a Pd-Ag hydrogen-permeating membrane reactor. The CH4 decomposition reaction hardly proceeded at temperatures lower than 773 K in a conventional fixed-bed reactor because of a chemical equilibrium limit. However, the conversion of CH4 was dramatically increased by removing the formed hydrogen by the Pd-Ag membrane. Because higher CH4 decomposition conversions were achieved at higher hydrogen removal rates in the Pd-Ag membrane, the removal of the formed hydrogen seems to be the key step for CH4 decomposition reaction at decreased temperature. Because a higher hydrogen permeation rate was achieved on the Pd(77)-Ag(23) membrane than on the Pd(90)-Ag(10) membrane, the CH4 conversion was always higher in membrane reactors using Pd(77)-Ag(23) than in reactors using Pd(90)-Ag(10) for the hydrogen separation membrane. The CH4 conversion increased with increasing contact time of the reactant and/or with increasing sweep Ar flow rate, because the hydrogen removal rate was improved. Consequently, this study revealed that CH4 decomposition into CO and H2 can occur with sufficiently high conversion (gt;88%) at 773 K and this process can provide hydrogen at decreased temperature.
|Number of pages||5|
|Journal||Industrial and Engineering Chemistry Research|
|Publication status||Published - Jul 10 2002|
All Science Journal Classification (ASJC) codes
- Chemical Engineering(all)
- Industrial and Manufacturing Engineering