硅/铝改性FeOOH及其煤直接液化催化性能

STUDY ON Si/Al MODIFIED FeOOH AND ITS CATALYTIC PERFORMANCE OF COAL DIRECT LIQUEFACTION

采用沉淀-空气氧化法分别制备了以Si含量2%~7%（物质的量比,下同）,Al含量2%~15%改性的FeOOH催化剂.采用BET,XRD,SEM和TG-DTG等表征手段,考察了Si和Al改性催化剂的微观结构和形貌,并在500mL高压釜内评估了对神东煤的直接液化催化性能.结果表明,随Si量增加,催化剂由α-FeOOH和γ-FeOOH转化为无定型六线水合氧化铁,Si超过5%时发生团聚;Si不影响FeOOH各物种的热分解温度,但会降低失重率.Al能持续改善催化剂织构性质,并取代Fe形成FexAl1-xOOH,使各物种分解向高温偏移.Si和Al改性FeOOH催化剂的煤转化率不变,但能降低氢耗,促进沥青向油转化,提高油收率;Si为5%,Al为10%~15%时催化性能分别达到最优.

FeOOH and Si/Al modified FeOOH catalysts were synthesized by aprecipitationoxidation method.The microstructures and morphologies of catalysts were characterized by BET,XRD,SEM,and TG-DTG.The coal liquefaction catalytic performances of the modified catalysts were evaluated in a 500 mL autoclave using Shendong coal.The results showed that the crystalline phases changed fromα-FeOOH andγ-FeOOH to amorphous ferrihydrite（6-line）along with the amount of Si increasing.The aggregation was detected when the catalyst was doped with more than 5%Si.The modification by Si didn＇t change the decomposition temperatures of FeOOH phases,but could reduce the weight loss in TG tests.Al could substitute with Fe to form Al-substituted FexAl1-xOOH,while increasing the decomposition temperatures of FeOOH phases in TG-DTG tests.The direct coal liquefaction results showed that Si and Al modified catalysts maintained the high coal conversion,reduced the H2 consumption and promoted the asphalt converting to oil thus improved the oil yield.The optimal amount of Si and Al was 5%and 10%-15%,respectively.