Processes And Performances Of Bio-asphalt Preparation By Straw Liquefaction

In the era of the two major problems of energy shortage and environmental pollution,biomass resources are gradually being valued because of their renewability.Our country produces nearly 900 million tons of straw every year,which can’t be effectively used.Catalytic liquefaction technology can convert waste crop stalks into liquid polymer materials for reuse.This paper uses waste rice straw as raw material to liquefy through catalytic liquefaction technology,explores the influence of different reagents and process conditions on the liquefaction rate,and uses the liquefied products in the preparation of bio-asphalt to reduce the dependence of pavement materials on petroleum resources,and realize the sustainable development of road materials.The specific contents are as follows:(1)The effect of liquefaction solvent and catalyst types on straw liquefaction effectAccording to the liquefaction effect of different types of liquefaction solvents on straw,This paper conducts straw liquefaction experiments with the single liquefaction solvent and the mixture of liquefaction solvent s in different proportions.Finally,three liquefaction systems of phenol(phenol),alcohol(glycerol: PEG400=1:4),and phenol-alcohol combination(glycerol: PEG400: phenol=3:7:10)are determined.Through the comparison of the catalytic liquefaction effects of different types of catalysts,20% sulfuric acid was selected as the catalyst.(2)Analysis of factors affecting straw liquefaction and liquefaction productsThrough single factor analysis,the effects of reaction temperature,reaction time,solid-to-liquid ratio,catalyst dosage,and pressure on the results of catalytic liquefaction of straw were studied,and the process conditions of the three liquefaction systems of phenol,alcohol,phenol-alcohol were optimized,under their respective best processes.The liquefaction rates of the three liquefaction systems are 96.53%,84.83%,and 91.24%respectively.This paper analyzes the three liquefied products under the best processes and straws.Through FTIR,it is found that the liquefied products contain a large amount of hydroxyl and carbonyl groups,but the functional group structures of different liquefied products are different.TG analysis shows that the main loss of three liquefaction products is between 200～500 ℃,and the mass loss at this stage is the fastest liquefied products under the phenol system,and the slowest under the alcohol system.SEM analysis found that there is a small amount of undecomposed fiber in the liquefaction residue residual.Polycondensation reaction occurred in the liquefaction process.Viscosity test showed that the liquefied product has fluid characteristics similar to asphalt.(3)Research on the preparation of bio-asphalt and its road performanceThe three liquefied products under the best processes of phenol,alcohol,and phenol-alcohol are used to prepare F bio-asphalt,C bio-asphalt,and H bio-asphalt at 5%,10%,and 20%,respectively.With carrying out the asphalt conventional performance experiment,the results found that with the increase of the liquefaction product content,the penetration of bio-asphalt gradually increased,the viscosity gradually decreased,the ductility first increased and then decreased,the softening point of C,H bio-asphalt gradually increased,and F bio-asphalt The softening point is the opposite.According to PI,PVN,VTS,viscous flow activation energy analysis,bio-asphalt has lower temperature sensitivity than matrix asphalt.From the MSCR results analysis of the anti-deformation ability,it can be seen that C bio-asphalt and H bio-asphalt are better than matrix asphalt,and F bio-asphalt is inferior to matrix asphalt.Based on the comparison of FTIR and TG results between bio-asphalts and liquefied products,it is considered that the physical reaction between liquefied product and matrix asphalt is the main one.The liquefaction product forms a good dispersion state in the asphalt and has good compatibility with the matrix asphalt.