生物质甘油经气化制甲烷Ni-Ce/Al2O3催化剂研究

Study on Ni-Ce/Al2O3 catalysts for methane production from reforming gases of biomass glycerol

关键词:  甘油重整气  甲烷化  Ni/Al₂O₃催化剂  Ce掺杂  甲烷 

Key words:  glycerol reforming gases  methanation  Ni/Al₂O₃ catalyst  Ce modification  methane

摘要:

采用浸渍法制备了助剂Ce掺杂的Ni/Al₂O₃催化剂,用于甘油重整气甲烷化反应,分别采用BET、XRD、H₂-TPR、CO₂-TPD等手段对催化剂进行了表征,并考察了Ce掺杂量、甲烷化温度、在线运行时间对Ce掺杂Ni/Al₂O₃催化甲烷化性能的影响。结果 表明,掺杂的Ce会优先占据Ni/Al₂O₃催化剂的微孔,抑制活性组分Ni与载体Al₂O₃相互作用而生成尖晶石NiAl₂O₄,促进表面高度分散的活性Ni的生成,其催化还原性、甲烷化性能得以提高。3%(w)Ce掺杂的Ni/Al₂O₃在甘油重整气甲烷化反应中最佳温度范围为275～300 ℃,CO和CO₂转化率分别可达99%和75%以上,每千克甘油经水蒸气重整、甲烷化反应后生成的甲烷量达到570 L以上。

Abstract:

Ce-modified Ni/Al₂O₃ catalysts for methanation of glycerol reforming gases were prepared by impregnation, and characterized by BET, XRD, H₂-TPR and CO₂-TPD respectively. And the effects of Ce amount, methanation temperature and time-on-stream on the catalytic properties of Ce-modified Ni /Al₂O₃ in the glycerol reforming gases to methane were also investigated. The results indicated that the introduced Ce species preferentially occupied on the surface of micro-pores of Ni/Al₂O₃ catalysts, inhibited the strong interaction between active Ni species and support Al₂O₃ to spinel NiAl₂O₄, and promoted the formation of highly-dispersed active Ni species. Therefore, the Ce-modified Ni/Al₂O₃ catalysts exhibited a higher catalytic property in methanation. For example, Ni/Al₂O₃ modified by 3 wt% of Ce exhibited an excellent catalytic stability at 275-300 ℃, received ratios of conversion towards CO and CO₂ with above 99% and 75% respectively. It was estimated that 1 kg biomass glycerol could produce 570 L of methane through the steam reforming and methanation according to the results in present work.