| The fast pyrolysis process of biomass is a major approach for obtaining bio-oil. The way to obtain bio-oil through fast pyrolysis process of biomass, realize a high value-added utilization of biomass. It has important potential applications and environmental value. The use of biomass pyrolysis oil is widespread. Burning it can generate heat directly after refining the oil. Mixed with diesel, gasoline and other fossil fuels, it can be used in internal combustion engine combustion, etc. However, low yield, high p H, and complex components of such bio-oil make it hard to be widely used. Therefor, this paper tried to use chemical reagent to pretreat pine sawdust, compare the change of oil yield and composition before and after the pretreatment, look for the simple and economic solution to obtain high quality biomass pyrolysis oil.First of all, the pine was used as research object, pretreated with sulfuric acid, acetone, acetic acid. Study the change of functional group, crystals and surface morphology of unpretreated and pretreated pine sawdust. Then use the biomass pyrolysis equipment in laboratory to study the primary pyrolysis research.To study the change of functional group, crystals and surface morphology of pretreated pine sawdust and consequent influence in bio-oil, the FT-IR, XRD, FSEM analysis methods were applied. The results showed that: the moderate pretreatment promoted the break of C-O bond in cellulose, hemicellulose and lignin, it was advantageous to the form of more short chains and conversion into bio-oil. Compared with the bio-oil yield of untreated pine 14%, the treated pine had high yield: sulfuric acid was 34%, acetone was 28%, acetic acid was 18%.Then the detailed research of sulfuric acid pretreatment of pine sawdust was conducted. The influence of sulfuric acid pretreated time, pretreated temperature, the ratio of solid to liquid, pyrolysis temperature and concentration of solvent were researched. The change of gas composition and ratio of solid liquid gas were also analyzed. The results showed that: it was the highest bio-oil yield 34% when the pretreated time was 2h,pretreated temperature was 20?, concentration of solvent was 2mol/l, solid to liquid ratio was 1:20, pyrolysis temperature was 550? with gas was 45.05%, coke was 20.95%. GC-MS was carried out to characterize bio-oil, and the result showed that after pretreatment, phenols, sugars were obvious increased, while aldehydes, acids, ketones, polycyclic aromatic hydrocarbons and benzenes was decreased.Finally TG was carried out to study pyrolysis characteristics.After processing,wood maximum weight loss rate and total weight loss increased significantly, and reached the highest 0.01506°C-1and 89.66% respectively at 2 mol/L sulfuric acid pretreatment. Three component model fitting was conducted to get the pyrolysis reaction function model. The highset bio-oil can get by simulation is when hemicellulose is 0.40, cellulose is 0.49, lignin is 0.11 respectively. |
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