稀土添加剂对镍转化催化剂性能的影响 Ⅲ.对水蒸汽吸附的TPD研究

The effect of rare earth additives on the catalytic behavior of the nickel catalysts for steam—natural gas reforming Ⅲ. TPD study on steam adsorption

用程序升温脱附技术对比研究了加和未加稀土的Ni/α-Al_2O_3.催化剂对水蒸汽的吸附特性。结果表明.单浸稀土和加有稀土的镍催化剂对水蒸汽的吸附有3个显著不同的吸附位,吸附能力主要是稀土的贡献。由于镍晶粒对稀土氧化物有复盖作用,故镍的存在削弱了对水蒸汽的吸附能力。催化剂浸渍方式不同,其镍晶粒对催化剂水蒸汽吸附能力的削弱程度也不同。添加稀土的镍催化剂不仅抗炭性能好,而且耐硫能力增强。

The absorbability to steam on the nickel catalyst unpromoted and promoted with rare earth was investigated comparatively by TPD technique. The experimental results show that there are three different steam adsorption sites on the surface for the sample with only impregnated rare earth and nickel catalysts promoted with rare earth. Because nickel crystallites can partly cover rare earth, the existence of nickel could weaken the steam adsorption capacity for the sample. For the catalyst promoted with rare earth, the different impregnation modes produce different effect on tie adsorption capacity to steam. The nickel catalysts promoted with rare earth possess good coking resistance,moreover their sulfur resistance is better than that of catalyst un promoted with rare earth.