Study On Enhancement Effect Of Ozone In Pretreatment Of Bagasse For Producing Bioethanol

The development of clean and renewable energy has always attracted human's attention.As a typical renewable energy,bioethanol is studied widely.Agricultural waste is aways used as raw material to product bioethanol.The pretreatment technology is the key step in bioethanol production.To find an economical and environmental friendly pretreatment technology is one of the objectives in bioethanol filed.In current pretreatment technologies,steam explosion?SE?is widely utilized,since it is cost-effective and adapts to different raw materials.But there are some problem in SE process,lile inhibitors and equipment corrosion.In this study,based on the advantages and disadvantages of SE treatment,ozone treatment was applied to enhance pretreatment effect of bagasse to product bioethanol production.A new idea was provided for the efficient utilization of agricultural waste.The enhancement effect of ozone treatment on bagasse SE pretreatment effect was studied first in this paper.It was found that ozone treatment could improve the SE effect of bagasse.With the ozone feeding time increasing from 0 min to 169 min?concentration 60?80 mg/m³,gas flow 1.5 m L/min?,the total sugar conversion(C_TRS,weight of released sugar/weight of carbohydrate in untreated bagasse)increased from 32.11%to 45.60%,and sugar yield 329.76mg/g?weight of released sugar/weight of untreated bagasse?.The enhancement mechanism of ozone treatment on bagasse SE pretreatment effect was studied by XPS,ATR-FTIR,CP/MAS NMR,SEM and XRD.The results showed that ozone damaged the structures of lignin and LCC,thus destroying the compound middle lamella and cell wall.Lignin was degraded to introduct organic acid to SE system,finally to improve the SE pretreatment effect.In order to get a environmental friendly pretreatment method,the enhancement effect of ozone on thermomechanical treatment?TM?was studied.With the ozone feeding time increased from 0 min to 5 min?concentration 167 mg/L,gas flow 1.5 L/min?,the C_TRS increased from30.12%to 60.55%,and the conversion of released sugar of enzymatic hydrolysis(C_RSE,weight of released sugar in enzymatic hydrolysis/weight of carbohydrate in untreated bagasse)increased from 8.55%to 38.98%.The influencing factors in thermomechanical-ozone pretreatment?TM-O₃?were studied experimentally.The results showed that moisture content and ozone feeding time were main factors.The chemical component analysis,ATR-FTIR and XPS analysis showed that the degradation of surface lignin by ozone was the key to improve the pretreatment effect.A response surface experiment was designed to optimize the conditions of ozone treatment in TM-O₃ pretreatment.Order the factors according to their influence on C_RSE:ozone feeding time>size>moisture content>acid dosage.The optimal conditions were 140?220 mesh,60.88%moisture content,1.0%acid dosage,and 6.73 min ozone feeding time?concentration167 mg/L,gas flow 1.5 L/min?.Under the optimum conditions,C_RSE and C_TRS were 41.13%and 62.70%respectively?sugar yield 453.39 mg/g?.