CAJ | 학술논문

采用等体积浸渍法制备了4种不同γ-Al2O3为载体的负载型Ni-Fe/γ-Al2O3催化剂，通过BET、XRD和H2-TPR等表征手段对载体和催化剂进行了表面微观结构分析，并考察了其低温浆态床催化CO甲烷化反应的活性和稳定性。结果表明，载体γ-Al2O3的表面织构性质对Ni-Fe/γ-Al2O3催化剂活性物质Ni的分布和甲烷化活性影响较大。比表面积和平均孔径分别为192m2/g和5.8nm的γ-Al2O3载体具有较好的低温浆态床CO甲烷化活性，有利于活性组分的分散，且与γ-Al2O3表面作用较强的β-NiO含量较多，还原后活性物质Ni晶粒较小，形成的活性中心数量多，甲烷化活性及稳定性较好，CO的平均转化率和CH4平均选择性分别达到97.0%和89.0%。而以比表面积较大的高硅γ-Al2O3载体制备的催化剂，游离态α-NiO含量较多，还原过程中容易迁移和团聚，形成较大的Ni晶粒，催化剂的活性和稳定性均差，CO的初始转化率为85.5%，反应17h后活性急剧下降。
채용등체적침지법제비료4충불동γ-Al2O3위재체적부재형Ni-Fe/γ-Al2O3최화제，통과BET、XRD화H2-TPR등표정수단대재체화최화제진행료표면미관결구분석，병고찰료기저온장태상최화CO갑완화반응적활성화은정성。결과표명，재체γ-Al2O3적표면직구성질대Ni-Fe/γ-Al2O3최화제활성물질Ni적분포화갑완화활성영향교대。비표면적화평균공경분별위192m2/g화5.8nm적γ-Al2O3재체구유교호적저온장태상CO갑완화활성，유리우활성조분적분산，차여γ-Al2O3표면작용교강적β-NiO함량교다，환원후활성물질Ni정립교소，형성적활성중심수량다，갑완화활성급은정성교호，CO적평균전화솔화CH4평균선택성분별체도97.0%화89.0%。이이비표면적교대적고규γ-Al2O3재체제비적최화제，유리태α-NiO함량교다，환원과정중용역천이화단취，형성교대적Ni정립，최화제적활성화은정성균차，CO적초시전화솔위85.5%，반응17h후활성급극하강。
Ni-Fe/γ-Al2O3 catalysts with four different γ-Al2O3 supports were prepared by incipient impregnation and characterized by XRD, BET and H2-TPR. Catalytic behaviors of the catalysts for low-temperature CO methanation were investigated in a slurry reactor. The results showed that the surface texture properties of γ-Al2O3 supports had great impact on distribution of Ni reactive species and methanation activity. Moderate specific surface area (192m2/g) and pore size (5.8 nm) of γ-Al2O3 was favor for the dispersion of active component, resulting in a higher amount of β-NiO and smaller Ni crystal particle size, which increased active sites, thus having better methanation activity and stability, with a CO conversion of 97.0% and a CH 4 selectivity of 89.0%. However, the catalyst prepared by high silica γ-Al2O3 support with larger specific surface area contained a great amount of α-NiO, which was inclined to agglomerate in the reduction process, resulting in low catalytic activity and stability, with a CO initial conversion of 85.5%and rapid deactivation after 17 hours.