ZrO2改性对Co-Ru／γ-Al2O3催化剂F-T合成性能的影响

Effect of ZrO_2 Modification on Catalytic Performance of Co-Ru/γ-Al_2O_3 for Fischer-Tropsch Synthesis

采用浸渍法制备Co-Ru双金属F-T合成催化剂,通过对催化剂进行BET、XRD和TPR表征,考察了ZrO2负载量对催化剂性能的影响,并在固定床反应器中研究了对合成重质烃反应性能的影响。结果表明,载体γ-Al2O3 ZrO2改性没有引起催化剂还原温度的降低,但可降低载体与Co间的相互作用;随ZrO2含量的增加,催化剂中易还原Co物种量增加;在623～693K下进行还原,催化剂具有较高的还原程度,呈现出良好的合成重质烃反应性能。同时,载体γ-Al2O3用ZrO2改性,可形成Co-ZrO2界面,使CO容易离解。在原料气n(H2)/n(CO)=2.0、503K、1.5MPa和空速800h-1下,15%Co0.4%Ru8.0%ZrO2/γ-Al2O3催化剂CO的转化率为93.27%,C5+的选择性82.56%,链生长概率0.81。

Using incipient impregnation method, Co-Ru bimetallic catalysts were prepared. With BET, XRD and TPD technique, the effects of the loaded ZrO2 amount on the properties were examined. And the effects on heavy hydrocarbon synthesis were investigated in a fixed-bed reactor. The results indicated the ZrO2 modification of support γ-Al2O3 didn＇t lead to a decrease in reduction temperature, and weaken the interaction between support and Co. Increasing ZrO2 content in catalyst, the amount of easily reducible Co species increased. Catalysts were reduced at 623-693K, the higher reduction extent of cobalt-based catalyst was obtained. And then it exhibited the better catalytic performance to synthesize heavy hydrocarbon. In the meanwhile, support γ-Al2O3 was modified with ZrO2, the interface of Co-ZrO2 would formed. The Co-ZrO2 interface facilitates CO dissociation. Under H2/CO molar ratio in feed 2.0, 503K, 1.5MPa, and 800h^-1, the catalyst exhibited better catalytic performance. The CO conversion was 93.27%, the selectivity was 82.56% and the chain growth factor was 0.81.