Ni/Ce-ZrO_2/γ-Al_2O_3催化剂上高温焦炉煤气中焦油组分的常压加氢裂解

Hydrocracking of Tar Components from Hot Coke Oven Gas over a Ni/Ce-ZrO_2/γ-Al_2O_3 Catalyst at Atmospheric Pressure

采用分步浸渍法制备了Ni/Ce-ZrO2/γ-Al2O3催化剂,并采用X射线衍射、透射电子显微镜、N2物理吸附和程序升温还原等方法对其进行了表征.该催化剂在以甲苯和萘为焦油模拟化合物的高温焦炉煤气常压加氢裂解反应中表现出良好的催化性能和一定的耐硫能力.在较低的水/碳摩尔比(S/C=0.44)条件下,甲苯和萘能够完全转化为小分子气体.向Ni/γ-Al2O3催化剂中加入适量的铈锆氧化物,能促使催化剂表面形成尺寸更小的镍纳米晶粒,并有效地抑制镍晶粒烧结,从而显著提高催化剂的稳定性.该类催化剂有望应用于具有较低水/碳摩尔比的高温焦炉煤气中焦油的直接除去.

Ni/Ce-ZrO2/γ-Al2O3 catalysts with different Ce-ZrO2 contents and Ni loadings were prepared by a two step impregnation method and characterized by X-ray diffraction, transmission electron microscopy, N2 adsorption, and temperature-programmed reduction. The catalysts were used for the hydrocracking of toluene and naphthalene, which were model tar compounds in hot coke oven gas, under atmospheric pressure at 800 ℃. They showed excellent catalytic activity, stability, and some sulfur tolerance. Both toluene and naphthalene was converted into light fuel gases even at a low mole ratio of steam to carbon （S/C = 0.44）. During the testing period of 7 h, no coke deposition was observed on the surface of the catalysts. The results indicated that the addition of Ce-ZrO2 limited the sintering of Ni particles and enhanced the catalytic activity. The Ni/Ce-ZrO2/γ-Al2O3 catalyst is promising for the direct removal of tar compounds in hot coke oven gas with low S/C ratios.