Catalytic Liquefaction Of Cellulose In Supercritical Methanol Over Modified Cu - Based Catalysts

Energy is one of the basic resources and strategic supplies for human survival and economic development. For the limit and unrenewable characteristics of the fossile fuel, the development of the replaceable and continuous green energy with low carbon contents are seriously considered. As a kind of clean energy, biomass fuels have attracted the attention of the worldwide countries recently. Considering with the characteristics of supercritical fluid, the biomass was liquefied under the catalytic hydrogenation, which is one of the effective methods to transform the solid biomass into liquid fuel and further contribute to the development and usage of the biomass energy industry.In this thesis, the micro-crystalline cellulose and typical biomass pine sawdust was selected to the catalytic liquefaction with Ce, La modified the Cu-based catalyst in supercritical methanol. The main contents are concluded as follows:The Ce, La modified the Cu-based catalyst was prepared by using coprecipitation method and the effects of different type and contents of the addition on the performance of catalysts were also characterized by XRD, TG/DTG and H2-TPR. Meanwhile, the catalytic liquefaction were conducted on which the percent conversion was set as the evaluation standard and the liquefied product was analyzed by GC-MS. Results show that the performance of catalysts was enhanced by the increasing contents of addition, where activity and stability were concluded. It should be noted that the catalytic liquefaction and the selectivity of alcohol products can reach optimal performance when the catalyst is Cui.2Zn4.8Al1.9Ce0.1.The research of single factor of MCC by using Cu1.2Zn4.8Al1.9Ce0.1 as catalysts was conducted in supercritical methanol to analyze the effects of experimental factors (reaction temperature, reaction time, dosage of catalyst and ratio of cellulose to methanol) on the convert ratio of MCC. Results show that the best reaction conditions are reaction temperature 320 ℃, reaction time 90min,75% dosage of catalyst,20:1 cellulose to methanol ratio with 20:1. Under this condition, the convert ratio is 99.89%.The liquefaction products of MCC and sawdust were analyzed by GC-MS. Results show that the liquefaction products of MCC was similar to sawdust and the liquefaction products of sawdust can be seen as the result of the combination of the three major components. The cellulose mainly produce alcohols, esters, ketones and other small molecule compounds and lignin with benzene, phenol derivatives as main product, while the hemicellulose main liquefied generat alcohols, ketones, furan compounds.The increase of reaction temperature intensified the cracking behavior of cellulose and hemicellulose, at the same time increased the activity of H-, thereby promoting generat alcohols.The reaction time main influenced the contents of alcohols, benzene, aldehyde, and the substance in liquefaction product can continue to dehydration condensation with the passage of reaction time, result in the increasing of aldehydes.Meanwhile, kinetics reactions of MCC were also studied in supercritical methanol using the fitting process of isothermol models. Results show that the apparent activation energy is 105.5 kJ/mol and the reaction kinetics model can be established as...