含氮化合物对柴油超深度加氢脱硫催化剂运行稳定性的影响

摘要

采用中型固定床加氢装置考察了含氮化合物对柴油超深度加氢脱硫Ni-Mo-W型催化剂运行稳定性的影响.通过元素分析、N2吸附-脱附、热重-质谱(TG-MS)联用、X射线光电子能谱(XPS)、高分辨透射电镜(TEM)等表征手段研究了催化剂失活的主要原因.实验结果表明:原料添加含氮化合物后,主要影响了催化剂的初活性,运转初期反应温度提高了7～10℃,但对催化剂的稳定性影响不大.根据催化剂失活原因的分析发现,原料添加含氮化合物前后,催化剂失活的主要原因均与其表面积炭的形成、孔体积的损失和边缘W比例的下降密切相关.%With using Ni-Mo-W/γ-Al2O3 catalyst, effect of nitrogen compounds on the running stability of ultra-deep hydro-desulfurization diesel catalyst was studied on a pilot plant unit.The reasons of catalyst deactivation were investigated by different characterization techniques which included elemental analysis, nitrogen adsorption-desorption, thermal gravity-mass spectrometry (TG-MS), X-ray photoelectron spectroscopy (XPS) and high resolution transmission electron microscopy (TEM).Experimental results suggest that nitrogen compounds mainly impact on catalyst initial activity, and lead to initial reaction temperature 7 to 10 ℃ higher.However, nitrogen compounds have little impact on catalyst stability.With/without nitrogen compounds adding into the feedstocks, the main reasons of catalyst deactivation are all mainly related to the surface coking, loss of pore volume and decrease of edge tungsten.