The Research On Liquefied Products Of Biomass Produced By Subcritical/Supercritical Technology

With high development of society, human face the serious energy crisis,seeking for new renewable energy become one of the global researchfocus, however biomasses are one of the most potential biomass energy,thus it is very important realistic significance for researching strawconversed into ethanol. This paper based on straw as raw material,researching in the area of pretreatment process, detoxification process,fermentation about different detoxification and continuous process ofsupercritical/ subcritical pretreatment process.In this paper, the four biomasses were liquefied by supercritical/subcritical technology and the effects of temperature and solid liquid ratioon reducing sugar yield and furfual were studied. The results were asfollows: In the condition of 368℃, solid liquid ratio 1:7.9, bagasse reachthe optimized reaction conditions; Straw had its optimized reactionconditions in 339℃, solid liquid ratio 1:5.7; In the condition of 358℃,solid liquid ratio 1:6, wheat reach the optimized reaction conditions; Rapehad its optimized reaction conditions in 339℃, solid liquid ratio 1:5.7.In this paper different detoxification methods were applied into theliquid produced by the subcritical/supercritical technology. Optimizedchemical detoxification method was excessive neutralized using calciumhydroxide, regulating pH and adding activated carbon to adsorption.Compared to optimized chemical method, reduced pressure distillationdetoxification method was more available based on the analysis ofGC-MS spectrogram. In bagasse case, four groups of contrast experiment was conducted, the results were as follows: The maximum ethanolconcentration fermented by optimized chemical detoxification liquid was32.5g/L, compared to 21.9 g/L fermented by non-detoxification liquid,ethanol rate increased by 48.4%. Ethanol reached the maximumconcentration of 38.3g/L detoxicated by reduced pressure distillation, rateincreased by 74.9% compared to non-detoxification liquid as well asincreased by 17.8% to chemical detoxification method. Thus,detoxification effect of reduced pressure distillation was more effectivethan optimized chemical detoxification method, providing bagasse with amore detoxification effect.Compared the influence factors on reduced sugar and furfural in bothcontinuous and batch reaction unit, in bagasses and straw case, resultswere as following: in the condition of H2SO4 of pH=5 as reaction mediain continuous reaction unit, amounts of reduced sugar of bagasse was21.8g, the related rate reached 72.67%, furfural percentage was 3.2538%.Rate of reduced sugar in continuous reaction unit increased 31.67%compared to batch reaction unit, as well soured 10.27% to water asreaction media in continuous reaction unit. For straw, amounts of reducedsugar reached 14.81g, rate to 49.37%, while furfural percentage was2.2285%, rate of reduced sugar in continuous reaction unit increased21.5% compared to batch reaction unit. Thus, in continuous reaction unitof the extremely low acid, biomass had a higher reduced sugarconcentration while lower furfural percentage. The problem ofdecomposition from reduced sugar was solved in continuous reaction unit,as well as reaching a higher rate, realizing the mode of higherconcentration of reduced sugar but lower toxicity.