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采用浸渍法将K添加到氢氧化铁的方法获得F-T合成制低碳烯烃K/Fe催化剂,探讨不同原子比KnFe1(n=0,0.02,0.04,0.08,0.40,1.0)对合成气直接制低碳烯烃CO加氢性能及活性物相变化的影响。并分别通过N2物理吸附、XRD、红外光谱、热重等手段进行表征。结果分析表明:随K含量的增加,低碳烯烃选择性先增加后减少;适当K含量的添加,能促进Fe3O4向Fe5C2转变,当K含量达到n=0.40时,又会抑制Fe3O4向Fe5C2的转变;与纯铁相比,适当含量K添加显著提高了CO转化率、CO_2选择性和C2=~C4=低碳烯烃选择性而降低了CH4的选择性。最佳催化剂(原子比n/n)为Fe:K=1:0.04,CO的转化率为77.33%,CO_2选择性为58.73%,CH4的选择性为12.24%,低碳烯烃选择性28.81%,烯烷比2.38。
The impregnation method was used to add K to ferric hydroxide to obtain low-carbon olefin K / Fe catalyst. The effects of different atomic ratios of KnFe1 (n = 0,0.02,0.04,0.08,0.40,1.0) Effects of Carbon Hydrogenation on Carbon Hydrogenation and Phase Transformation of Activated Carbons. And were characterized by means of N2 physical adsorption, XRD, infrared spectroscopy and thermogravimetry, respectively. The results show that with the increase of K content, the selectivity of light olefins increases first and then decreases. The addition of proper K content can promote the transformation of Fe3O4 to Fe5C2. When the content of K reaches n = 0.40, the conversion of Fe3O4 to Fe5C2 is also inhibited ; Compared with pure iron, the addition of appropriate content of K significantly increased the CO conversion, CO 2 selectivity and C2 = ~ C4 = light olefin selectivity and reduce the CH4 selectivity. The optimal catalyst (atomic ratio n / n) is Fe: K = 1: 0.04, the conversion of CO is 77.33%, the selectivity of CO 2 is 58.73%, the selectivity of CH4 is 12.24%, the selectivity of light olefins is 28.81% Alkane ratio 2.38.