水蒸气浓度对合成气制甲烷Ni/γ-Al_2O_3催化剂稳定性影响

Effect of water vapor concentration on stability of Ni/γ-Al_2O_3 catalyst in syngas methanation

通过改变反应体系中水蒸气浓度,考察了不同水蒸气浓度对γ-Al2O3负载的镍基催化剂上合成气制代用天然气(SNG)的反应活性和稳定性。采用X射线衍射、扫描电镜、N2吸附-脱附等技术对催化剂进行了表征。结果表明,催化剂的稳定时间与反应体系中水蒸气的浓度成反比。影响催化剂稳定性的主要因素可能是在高水蒸气浓度的合成气制SNG的反应条件中,γ-Al2O3的水合反应及其引起的γ-Al2O3相变。

Add nitrogen into reactor to change the concentration of water vapor in the reaction system. Catalytic behaviors of nickel-based catalysts with support （γ-Al2O3） for syngas methanation under different water vapor concentrations were investigated. The catalysts were characterized by X-ray diffraction, Scanning electron microscope, N2 adsorption-desorption. Characterization results showed that the main factor influencing the stability of catalyst might be γ-Al2O3 hydration. The stable time of the catalyst was inversely proportional with the concentration of water vapor of the system. γ-Al2O3 hydration phase transition led to the deactivation of the catalyst.