介孔Ni/MgO催化剂催化水蒸气重整生物质油制氢

采用水热法制备了介孔MgO作为催化剂的载体,并制备了介孔Ni/MgO催化剂。利用N_2吸附-脱附、XRD、H_2-TPR等对样品进行表征,并考察了介孔Ni/MgO催化水蒸气重整糠醛、生物质油模型物和两种商用生物质油制氢的活性。结果表明,在介孔Ni/MgO催化剂催化水蒸气重整糠醛制氢反应中,随着反应温度的提高,水蒸气重整糠醛中糠醛的转化率、氢气的产率和氢气的选择性,都呈现递增的趋势。在反应温度提高到600℃时,糠醛的转化率和氢气的产率分别达到94.9%和83.2%。Ni/MgO催化水蒸气重整二组分模拟生物质油,糠醛/乙酸、糠醛/羟基丙酮制氢的反应中,氢气的产率分别达到87.3%和86.8%,均高于水蒸气重整糠醛反应中氢气的产率。由此表明,乙酸或羟基丙酮的存在,提高了模拟生物质油中主要有机物组分糠醛的转化率,并相应地提高了氢气的产率。在水蒸气重整商用生物质油制氢反应中,随着反应物水碳比(S/C(molar ratio)=5、10、15、20、25)的提高,主要有机物的转化率、氢气的产率和选择性呈现出增加的趋势。在水碳比为20时,两种生物质油的主要有机物组分(糠醛、乙酸和羟基丙酮)的转化率均可达90%以上,氢气的产率也达到81.0%以上。由此可知,Ni催化剂对于水蒸气重整商用生物质油也具有较高的催化活性。

Hydrogen production by steam reforming of bio-oils over mesoporous Ni/MgO catalyst

A catalyst support of mesoporous MgO was prepared using hydrothermal method, with which a mesoporous Ni/MgO catalyst was prepared by impregnation method. The hydrogen production experiment by steam reforming of biomass oil models and two kinds of commercial biomass oils over the mesoporous Ni/MgO catalyst was conducted. The results show that the furfural conversion, hydrogen yield and hydrogen selectivity increase with increasing the reaction temperature. When the reaction temperature is increased to 600 ℃, the furfural conversion and the hydrogen yield reach 94.9% and 83.2%, respectively. In addition, the hydrogen yields for steam reforming of furfural/acetic acid and furfural/hydroxyacetone reach 87.3% and 86.8%, respectively, which are higher than the corresponding hydrogen yields in steam reforming furfural. The result indicates that the acetic acid or hydroxyacetone can promote the conversion of furfural which is the main organic component in the simulated biomass oil. When the commercial biomass oils is used, the conversion of main organics, hydrogen yield and hydrogen selectivity exhibit an increasing trend with the increase of the ratio of water to the carbon of reactant (S/C = 5, 10, 15, 20, 25). Under the S/C(molar ratio)=20, the conversion of main organic components (furfural, acetic acid, and hydroxyacetone) in two kinds of biomass oils can reach more than 90% and the yield of hydrogen can also be more than 81.0%, showing that the mesoporous Ni/MgO catalyst also has higher catalytic activity for the steam reforming of commercial biomass oils.