Syngas Production By Steam Reforming Of Glycerol Catalysed By Supported Ni Catalysts

The increase of the biodiesel production leads to a large amount of glycerol as a byproduct. Therefore, the efficient use of glycerol to produce value added products is significant to cut down the overall cost of the biodiesel production and promotes the resource utilization. In comparison with the traditional method, the syngas production by using steam reforming of glycerol is advantageous because it is environmental benign and with a high utilization of resources. In this thesis, the catalysts used for and the process conditions of the steam reforming reaction of glycerol for syngas were investigated.First, Ni catalysts with different support materials such as MgO, CeO2, SiC, SiO2and Al2Os were prepared. The performance of these catalysts for the steam reforming of glycerol for syngas was examined. In particular, their effect on the water-gas-shift (WGS) reaction, which was very sensitive to the H2/CO ratio, was studied. The results indicated that H2/CO ratio was difficult to control by using Ni catalysts with both acidic and base supports because they are relatively active to the WGS reaction. A suitable H2/CO ratio for syngas could be obtained by catalysts with neutral supports, such as SiO2and SiC, by which the WGS reaction was easy to control. The H2/CO ratio of the product of steam reforming of glycerol catalyzed by Ni/SiO2was about2.Second, at450℃the other process conditions of the steam reforming of glycerol for syngas with the catalyst Ni/SiO2were studied and optimized. With a feed rate of0.5ml/min of20wt%glycerol solution, the H2/CO ratio of the steam reforming product could be kept at2, which is suitable for the F-T synthesis. A conversion rate of70%was obtained for glycerol. Meanwhile, the activity of the catalyst used was stable under a pressure of0.1-2MPa. The catalytic performance of the catalyst shown no obvious decrease after27hours’reaction.Third, catalysts modified by different metal (Co, Cu, Sn) and different oxide (ZrO2, A12O3, CeO2) have been studied. The results indicated that the performance of the Ni/SiO2catalyst modified by metal Co was obviously promoted. At450℃, the conversion of glycerol could reach78.6%, and a ratio of H2/CO about1.94was obtained. The use of oxide hybrid as supporter of the catalyst could improve the conversion of glycerol. For the Ni/ZrO2-SiO2catalyst, the conversion of glycerol could reach100%at550℃, but the addition of basic oxides promoted the WGS reaction, and led to a low amount of CO in the product.