磷化钨催化剂抗硫性能研究

STUDY ON THE SULFUR RESISTANT PERFORMANCE OF TUNGSTEN PHOSPfflDE CATALYST

以磷酸氢二铵和偏钨酸铵为原料,采用高纯氢气程序升温还原磷钨酸盐的方法制备了非负载型WP和负载量为30％的负载型WP／γ-Al2O3催化剂。通过对噻吩加氢脱硫反应20 h前后的 WP催化剂进行XRD,IR,XPS表征发现,反应前后催化剂体相晶体结构没有改变,反应后催化剂表面 S元素的原子摩尔分数仅为0．04％,WP催化剂具有较好的抗硫结构稳定性。通过对CS2强硫化处理和200h噻吩加氢脱硫反应前后WP／γ-Al2O3催化剂进行XRD、XPS表征和催化活性评价,考察了负载型磷化钨催化剂的抗硫性能。结果表明,WP／γ-Al2O3催化剂具有较好的抗硫性能,反应前后催化剂的XRD谱图几乎没有变化,反应后催化剂表面S元素的原子摩尔分数仅为1．36％;对WP／γ-Al2O3催化剂进行强硫化处理,并没有使催化剂活性降低,与相应的未进行强硫化处理的WP／γ-Al2O3催化剂的噻吩HDS转化率接近,说明该催化剂具有稳定的催化活性。

Using diammonium phosphate and ammonium metatungstate as raw material, bulk tungsten phosphide catalyst and alumina supported tungsten phosphide catalysts were prepared by temperatureprogrammed reducing phosphate precursors in hydrogen. XRD, XPS and IR were used to characterize the bulk tungsten phosphide catalyst before and after 20 h hydrodesulfurization （HDS） reaction with thiophene. It was found that the bulk phase was not changed after reactions and the sulfur content on the catalyst surface was only 0. 04%, which indicated that the catalyst had good structure stability. The WP/γ-Al2O3 catalyst with a tungsten phosphide loading of 30% was severe sulfurized and its thiophene HDS activity was tested for 200 h to observe the sulfur resistant performance of the catalyst. The results showed that the XRD spectrum of the catalyst had no obvious changes before and after HDS reaction. Sulfur content of the catalyst surface was 1.36%, and the sulfur atoms likely existed in the chemical absorption state. The severe sulfurization had little effect on the catalyst activity, indicating that the WP/γ-Al2O3 catalyst possessed good sulfur resistant property and stable catalytic activity.