助剂改性FeOOH及其煤直接液化催化活性

采用共沉淀法分别引入Si、Al、La、Ca、Mg、Zr、Cu、Ni和Co 9种助剂元素对FeOOH催化剂改性,借助BET、XRD、SEM手段表征各助剂对催化剂微观结构、晶相和形貌的影响,在0.5 L高压釜内测试各催化剂对神东煤的直接液化催化活性。结果表明,引入Si、Al、Ca、Zr、Ni、Co能改善催化剂比表面积和分散度,分别提高煤液化油收率0.7～2.7个百分点;Ni和Co为最优助剂,Mg没有促进作用,Cu、La降低了油收率。研究表明,Al、Ca、Zr是通过结构支撑改善催化剂的织构性质,促进生成易于转化为活性相的小晶粒g-FeOOH,Ni、Co主要起到电子型助剂作用,通过强化对氢气的活化,促进煤的转化,提高油收率。

Promoters modified FeOOH and their catalytic performances for direct coal liquefaction

Modified FeOOH catalysts were prepared by a co-precipitation method using Si, Al, La, Ca, Mg, Zr, Cu, Ni and Co as promoters, respectively. The effects on microstructures, crystalline phase and morphology of the catalysts were characterized by BET, XRD and SEM. Their catalytic performances for the direct liquefaction of Shendong coal were evaluated in a 0.5 L stirring autoclave. The results showed that these promoters (Si, Al, Ca, Zr, Ni and Co) could improve the dispersion of the catalysts and surface area, and then improve the catalytic performances for direct coal liquefaction. Increasing by 0.7%—2.7% oil yield over the unmodified the catalyst could be obtained. However, Mg showed no effect on catalytic ability, while Cu and La reduced the Oil yield. The result indicated that Si, Al, Ca and Zr as the structure promoters could significantly improve the texture properties of catalysts, resulting in an increase of γ-FeOOH crystalline phase with small size which was beneficial to form active phase (Fe_1-xS). Co and Ni as the electronic promoters could activate H₂ preferentially to promote liquefaction, leading to the rising in oil yield.