Ni-Co/Al_2O_3催化乙醇水蒸气重整制氢性能研究

利用浸渍法制备Ni-Co/Al2O3催化剂,考察催化剂组成、反应温度、水醇比、液体空速对乙醇水蒸气重整反应的影响。结果表明,Ni-Co/Al2O3催化剂中Co含量的增加会提高氢气和一氧化碳的选择性,降低甲烷和二氧化碳的选择性,催化剂Ni7.5Co7.5催化性能最佳,450℃时乙醇转化率达到100%,氢气选择性为79.78%,二氧化碳选择性为91.89%。反应温度会影响乙醇水蒸气重整制氢反应中相关反应的权重和产物的分布。加大水醇比降低一氧化碳选择性,提高二氧化碳选择性;提高液体空速,加大一氧化碳选择性。Ni-Co/Al2O3催化剂反应前后发生明显的物相重构,Co3O4被还原成Co,Co与Ni共同起活性作用,Co3O4作为催化剂前体在乙醇水蒸气重整中显示出良好的活性。

Performance of Ni-Co/Al2O3 used for preparation of hydrogen from ethanol steam reforming

Catalysts Ni-Co/Al2O3 were prepared with impregnation method,the effects of the catalysts composition,the reaction temperature,the H2O/C2H5OH ratio,and the liquid space velocity on the hydrogen production from ethanol steam reforming(SRE) were investigated.The results indicated that the increasing of Co content increased the selectivity of H2 and CO,decreased the selectivity of CH4 and CO2,catalyst Ni7.5Co7.5 showed optimum performance,the conversion of ethanol and selectivity of H2,CO2 reached 100%,79.78%,91.89% at 450 ℃,respectively.The contribution of relevant reactions in SRE system and the distribution of production were strongly influenced by the reaction temperature.The selectivity of CO decreased and the selectivity of CO2 increased with the H2O/CH5OH ratio going up,the selectivity of CO increased with the liquid space velocity increasing.The phase composition changed greatly before and after reaction,Co3O4 was reduced to Co,Ni and Co acted as the active component together,Co3O4 as the precursor in the Ni-Co/Al2O3 catalyst exhibited good activity in SRE.