镍、钒对FCC催化剂结构和反应性能的影响

Effect of Nickel and Vanadium on Structure and Catalytic Performance of FCC Catalyst

分别通过浸渍法和循环污染法对Y型分子筛和FCC催化剂进行镍、钒污染,考察了在干燥和水热条件下镍、钒对分子筛结晶度的影响,采用高级催化裂化评价装置(ACE)评价了镍、钒污染的FCC催化剂及稀土改性FCC催化剂的催化性能。结果表明,只有在水蒸气存在条件下,钒会破坏分子筛的晶体结构;在REY分子筛中,镍的存在对分子筛结构的破坏略有影响。在FCC催化剂中,镍、钒之间存在相互作用,与单独钒污染的催化剂相比,镍、钒同时污染的催化剂的比表面积和微反活性略有提高,反应转化率由72.14%增至78.02%,重油收率由10.49%下降至7.62%。与相应的镍、钒污染FCC催化剂相比,镍、钒污染的稀土改性FCC催化剂所得转化率与总液体收率均明显增加,重油收率下降,稀土元素的引入提高了催化剂的抗镍、抗钒性能,提高了催化剂的催化性能。

Nickel（Ni）and Vanadium（V）contaminated Y zeolite and FCC catalysts were prepared by impregnation method and cyclic contamination,respectively.The effects of Ni and V on the crystallinity of zeolite in dry atmosphere and hydrothermal condition were investigated.The catalytic performance of FCC catalyst and rare earth element（RE） modified FCC catalysts contaminated by Ni and V were tested in an advanced catalytic cracking evaluation（ACE）device.Results showed that the effect of V on crystallinity of Y zeolite was evident only when steam was present.For the rare earth containing zeolite,Ni destroyed the zeolite structure slightly.A direct interaction existed between V and Ni in FCC catalyst. Compared with the FCC catalyst contaminated only by V,the FCC catalyst contaminated by both Ni and V possessed more specific surface area and slightly more MAT value,with the increase of reaction conversion from 72.14% up to 78.02%,the decrease of heavy oil yield from 10.49%to 7.62%.The conversion and total liquid yield of FCC reaction were higher,the heavy oil yield was lower over the RE modified FCC catalyst contaminated by both Ni and V than those over the Ni and V contaminated FCC catalyst,meaning that the introduction of rare earth elements in FCC catalysts enhanced the tolerance to Ni and V and cracking performance of the catalyst.