The effects of temperature and pressure on the steam reforming of methane （CH4＋H2O→← 3H2＋CO） were investigated in a membrane reactor （MR） with a hydrogen permeable membrane. The studies used a novel silica-bas...The effects of temperature and pressure on the steam reforming of methane （CH4＋H2O→← 3H2＋CO） were investigated in a membrane reactor （MR） with a hydrogen permeable membrane. The studies used a novel silica-based membrane prepared by using the chemical vapor deposition （CVD） technique with a permeance for H2 of 6.0×10^-8 mol·m^-2.s^-1.Pa^-1 at 923 K. The results in a packed-bed reactor （PBR） were compared to those of the membrane reactor at various temperatures （773-923 K） and pressures （1-20 atm, 101.3-2026.5 kPa） using a commercial Ni/MgAl2O4 catalyst. The conversion of methane was improved significantly in the MR by the countercurrent removal of hydrogen at all temperatures and allowed product yields higher than the equilibrium to be obtained. Pressure had a positive effect on the hydrogen yield because of the increase in driving force for the permeance of hydrogen. The yield of hydrogen increased with pressure and reached a value of 73× 10^-6 mol·g^-1 .s^-1 at 2026.5 kPa and 923 K which was higher by 108% than the value of 35×10^-6 mol·g^-1.s^-1 obtained for the equilibrium yield. The results obtained with the silica-based membrane were similar to those obtained with various other membranes as reported in the literature.展开更多
文摘The effects of temperature and pressure on the steam reforming of methane （CH4＋H2O→← 3H2＋CO） were investigated in a membrane reactor （MR） with a hydrogen permeable membrane. The studies used a novel silica-based membrane prepared by using the chemical vapor deposition （CVD） technique with a permeance for H2 of 6.0×10^-8 mol·m^-2.s^-1.Pa^-1 at 923 K. The results in a packed-bed reactor （PBR） were compared to those of the membrane reactor at various temperatures （773-923 K） and pressures （1-20 atm, 101.3-2026.5 kPa） using a commercial Ni/MgAl2O4 catalyst. The conversion of methane was improved significantly in the MR by the countercurrent removal of hydrogen at all temperatures and allowed product yields higher than the equilibrium to be obtained. Pressure had a positive effect on the hydrogen yield because of the increase in driving force for the permeance of hydrogen. The yield of hydrogen increased with pressure and reached a value of 73× 10^-6 mol·g^-1 .s^-1 at 2026.5 kPa and 923 K which was higher by 108% than the value of 35×10^-6 mol·g^-1.s^-1 obtained for the equilibrium yield. The results obtained with the silica-based membrane were similar to those obtained with various other membranes as reported in the literature.
