Research On Catalytic Liquefaction Of Corn Straw Under Atmosphere Pressure And Analysis Of Liquefied Products

With the increasing depletion of fossil fuels,the emergence of global warming as well as the increasingly serious environmental pollution problems,developing the utilization technologies of environment-friendly biomass and transforming sustainable,renewable abundant biomass resources into clean cheap,high-grade biomass,has an important practical and far-reaching historical significance.In hence,the typical crops of corn straws was selected as raw materials,the chemical composition of liquefied products were analyzed qualitatively and quantitatively,the theory and technical support was provided for prepareing the high quality bio-fuel and chemicals.By comparing various catalysts and liquefying agents,concentrated phosphoric acid was selected as catalyst,polyethylene glycol with ethylene carbonate was used as the liquefaction agent.The effects of reaction temperature,reaction time and amount of catalyst on the yield of liquefaction were investigated,and the optimum condition was found to be:reaction temperature 170 ?,reaction time 60 min,catalyst dosage 10%(w/odw).FT-IR analysis indicated that the functional groups of cellulose,hemicellulose and lignin were disappeared,and many active chemical bonds which can increase the entire reaction system showed up in the liquefied products.GC-MS analysis showed that the liquefied products of glyceryl triacetate with ethylene carbonate as agent had 64 kinds of compounds,and the ethers and alcohols were the highest,relative content was 44.81%;the liquefied products of glyceryl with ethylene carbonate as agent had 55 kinds of compounds,and the acids and ketones were the highest,relative content was 33.51%;the liquefied products of polyethylene glycol with ethylene carbonate as agent had 40 kinds of compounds,and the aromatic was highest one,relative content was 30.95%.TGA analysis revealed that residues were seriously condensated,the 60%residual carbon can not be burned when the temperature was 600 ?.The model Box-Behnken in the Design-Expert software was used to design the experiment scheme,and Corn straw was fixed at 10 g.The center point condition was reaction temperature 170 ?,reaction time 60 min,catalyst dosage 10%.The effect of liquefaction yield,the product viscosity,acid,heavy oil components and ash were invested respectively.The results indicated that the optimal condition was temperature 159 ?,reaction time 74 min,catalyst dosage 6%.Under the experimental conditions,the liquefied yield of corn starw reached 94.12%,an acid value was 26.84 mgKOH/g,viscosity was 48.30 mP s,heavy oil component was 52.06%,ash content was 3.83%.The thesis also examined the various physical and chemical properties of liquefied bio-oil.The results indicated that the stability of bio-oil prepared by the method was really good,and the solid particles were uniformly dispersed in the liquid,but the solids and ash content were very high,relative content were 11.33%and 3.83%,the degradation speed of bio-oil was most fast between 250 ?-350 ?;The surface tension was 35.29 mN·m-1 at normal temperature.