Hydrothermal Catalytic Liquefaction Of Corn Stalk For Preparation Of Bio-oil

Under the dual pressure of energy and the environment, it is urgent to search for environment and renewable liquid fuel. Biomass as the fourth-largest energy sources in the world has aroused widely public attention. Hydrothermal liquefaction is a technique which can convert biomass to renewable liquid fuel has also aroused public attention. In our work,we use the most commonly seen agricultural residues--corn stalk as the feedstock, and choose the HZSM-5 and FeHZSM-5 as the heterogeneous catalysts, and then conduct the hydrothermal catalytic liquefaction. The influence of reaction temperature and catalyst quantity as well as reaction time on the products distribution was investigated. The main components, functional groups and elements of bio-oil with and without catalysts were characterized by gas chromatography/mass spectrometry(GC-MS), Fourier transform infrared spectrometry(FT-IR) and element analysis.The FeHZSM-5 were prepared by impregnation of Fe(NO3)3 solution and characterized by X-ray diffraction(XRD) and ICP. In the hydrothermal catalytic liquefaction, we use the FeHZSM-5(Si/Al ratio is 25) as the catalyst and investigate the influence of reaction temperature, catalyst quantity and reaction time on the products distribution. The result shows that the optimal conditions of liquefaction are 15 g CS with 6.67% FeHZSM-5 at 340? for 30 min, at which the bio-oil yield reaches a maximum of 28.03% with the highest CS conversion of 81.73%. The bio-oil yield increased almost 6% compared with without catalyst. The HHV of the bio-oil reaches to 30.08MJ/kg. The main components of the bio-oil are phenols and long-chain esters. At the same time, the content of hydrocarbons and ester has an increase compared to the bio-oil which liquefaction without catalyst. On the contrary, the ketones decreased. This will be helpful for the application of the bio-oil.At the optimal liquefaction conditions, we use the different Si/Al ratio(25,38,50)catalysts HZSM-5 and FeHZSM-5 to investigate the influence on the the bio-oil yields and the composition. The result shows that the low Si/Al ratio HZSM-5 can promote the bio-oilgeneration. And also the loaded of the Fe3+make a good influence on the bio-oil yield.Meanwhile the phenols in the bio-oil decreased and the hydrocarbons increased with the increasing of the Si/Al ratio. The high Si/Al ratio can facilitate the biomass convert to small molecular substances.