用TiO_2-Al_2O_3混合载体提高镍催化剂抗结碳性能的研究

用混合法制备一系列α-Al_2O_3 TiO_2的混合载体,用湿浸法制成Ni/(α-Al_3O_3-TiO_2)催化剂。在动态热重装置上,利用正庚烷的蒸汽转化反应考察载体中不同的TiO_2含量对积碳速率的影响。结果表明,载体中适当的TiO_2加量(TiO_2含量占30％左右)能明显地改善催化剂的抗结碳性能。本文根据积碳机理对实验得出的积碳速率与载体中TiO_2含量之间的“V”形曲线关系,进行了初步探讨,并对Ni/TiO_2上积碳的负活化能进行了讨论。

RESISTANCE TO CARBON FORMATION OF Ni-CATALYSTS ENHANCED BY TiO2-Al2O3 SUPPORT

Supports mixed with different ratio of a-Al2O3 and TiO2 have been used for the preparation of supported Ni-catalysts by wet impregnation. The effects of the TiO2 content in supports on the rates of carbon formation were investigated at the condition of steam reforming of n-heptane in a dynamic thermogravimetric system. The results indicate that carbon formation was inhibitated by adding an optimium content of titania and alumina. The optimized support is composed of 30% TiO2 and 70% a-Al2O3. The effect of titania on the rate of carbon formation was briefly discussed on the basis of the mechanism of carbon deposition.