ZrO_2改性对Co-Ru/γ-Al_2O_3催化剂F-T合成性能的影响

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。

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

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.