Steam Reforming Of Model Compounds Of Bio–iol For Hydrogen Production

Hydrogen as a new energy source with high efficiency and cleanness has been widely concerned.Abundant biomass resources and environmental protection were considered to be the best alternative energy source for fossil fuels in the future,which was considered as the best alternative energy for fossil fuels to ensure the sustainable development of future energy.Due to the complexity of biomass oil components,this thesis will focus on steam reforming several kinds of biomass oil model compounds,and explore the influence of molecular structure on steam reforming reaction process.The main findings and innovations are as follows:1.Biomass oil contains a small amount of carboxylic acids,which in addition to acetic acid also contains formic acid,propionic acid and butyric acid.Therefore,the four kinds of acidic aqueous solutions were selected as reactants.At 400 ^oC,the conversion of Ni/Al₂O₃ on the steam reforming of different carboxylic acids was as follows:formic acid>acetic acid>propionic acid>butyric acid.In homogeneous decomposition reaction,the acids containing the C–C bond were more stable than the formic acid.With the increase of the length of carbon chain,the conversion of carboxylic acids and the yields of gas decreased.At the same time,carboxylic acids with long aliphatic carbon chain,such as propionic acid and butyric acid,also had higher tendency to accumulate coke than formic acid and acetic acid.2.A series of Mn,Fe,Co,Ni,Cu and Zn transition metal catalysts supported on Al₂O₃ were prepared by impregnation method.The unsupoported transition metal catalysts were also prepared by precipitation method.It was found that the stability of Cu–based catalyst supported on the support was higher than that of the unsupported metal Cu catalyst,and the metal support inhibited the sintering of Cu particles.Ni–based and Co–based catalysts showed high activity in the steam reaction of ethanol and acetone,and the carbon deposition of the catalyst after the stability test was analyzed.3.The composition of bio–oil was very complex,several model compounds of methanol,ethanol,formic acid,acetic acid,acetaldehyde,acetone,aether,furfural,guaiacol,n–hexane and cycloethane were selected and their catalytic behavior in steam reforming reaction was studied.Methanol,ethanol,formic acid,acetic acid,acetaldehyde and acetone are easy to be reformed,while furfural and guaiacol were relatively difficult to reform due to the increase of the molecular structure of the carbon chain.Different compounds had different tendency to accumulate coke in reforming reaction.The deactivation of the catalysts during steam reforming n–hexane and cyclohexane was caused not coke deposition but by the formation of NiLaO₃ species,which resulted in the oxidation of the active metal site of Ni in the catalyst.