【作者】 马晶；

【导师】 申哲民；

【作者基本信息】 上海交通大学 ， 环境工程， 2011， 硕士

【摘要】 随着社会能源需求的不断增长与环境污染的日益严重,以生物质秸秆为原料生产燃料乙醇有着广阔的市场前景。超临界技术为生物质秸秆的资源化利用提供了一条新的途径。本论文利用亚/超临界-发酵组合技术对生物质秸秆进行处理及资源化研究,利用间歇式高压反应釜,以生物质秸秆亚/超临界反应所产生的还原糖及发酵产生的乙醇为目标产物,研究了生物质秸秆亚/超临界处理的影响因素和液化产物的脱毒及发酵条件。本文采用亚/超临界技术对生物质秸秆进行水解,探讨了温度和固液比等因素对还原糖产率与浓度的影响。结果表明甘蔗渣在最佳温度343℃与最佳固液比1:3.7时,还原糖产率达30.4%,还原糖浓度为141.55g/L;稻草秸在最佳温度332℃与最佳固液比为1:3.6时,还原糖产率达20.6%,浓度为119.98g/L;小麦秸在最佳温度335℃,最佳固液比为1:6.5时,还原糖产率与浓度达23.75%, 62.17g/L;玉米秸在最佳温度312℃,最佳固液比1:3时,还原糖产率与浓度达34.9%,106.65g/L;油菜秸在最佳温度319℃,最佳固液比为1:5时,还原糖产率与浓度达34.21%,79.86g/L。本论文优化了超临界处理后的反应液的脱毒方法:将得到的超临界反应液,缓慢加入Ca（OH）₂,至pH=8-9,在60℃下放置,待Ca（OH）₂完全沉淀,抽滤得液体,用磷酸溶液调pH至5。再加入3%活性炭,50℃下搅拌30min,冷却后抽滤得液体。论文对反应液发酵的脱毒效果、菌种驯化、接种量以及培养基营养盐的配比等进行了探讨。结果表明,脱毒后的反应液更利于发酵,乙醇产率提高了35.6%;驯化后的酿酒酵母发酵产生的乙醇浓度由32g/L上升到42.9g/L,可能由于液化产物中酵母发酵抑制物的脱除尚不完全。最佳接种量为10%,pH值为5,最佳营养盐配比为:0.1g/L MgSO₄·7H₂O,0.15g/L KH₂PO₄,0.4g/L（NH₄）2SO4,并做验证实验,得乙醇浓度为52.6g/L。实验采用20g甘蔗渣在343℃,固液比为1:3.7时,还原糖产率为30.4%,产生还原糖浓度为141.55g/L。经计算,每生产1t乙醇需要2.09t还原糖,即需要6.88t甘蔗渣,则还原糖的利用效率为47.85%,纤维素的产糖率为75.94%,纤维素转化为乙醇的利用率为36.12%。更多还原

【Abstract】 With the rising demand for liquid fuels and environment protection, the production technology of fuel ethanol from biomass is in great potential. Supercritical technology provides an effective method for the reutilization of biomass. The disposal and reutilization of biomass were realized by combined subcritical/supercritical and fermentation technology. To obtain high reducing sugar yield and concentration by subcritical/supercritical reaction and ethanol by fermentation, the influence factors, detoxification of liquefaction products and fermentation conditions were investigated.In this paper, the biomass was liquefied by subcritical/supercritical technology and the effects of temperature and solid liquid ratio on reducing sugar yield and concentration were studied. The results were as follows: （1） In the condition of 343℃, solid liquid ratio 1:3.7, the reducing sugar yield and concentration of bagasse can reach the maximum value 30.4% and 141.55g/L; （2） The reducing sugar yield and concentration of rice straw can reach the highest value 20.6% and 119.98g/L in the condition of 332℃, solid liquid ratio 1:3.6; （3） In the condition of 335℃, solid liquid ratio 1:6.5, the reducing sugar yield and concentration of wheat can reach the maximum value 23.75%,62.17g/L; （4） The reducing sugar yield and concentration of corn can reach the highest value 33.72% and 106.65g/L in the condition of 312℃, solid liquid ratio 1:3; （5） In the condition of 319℃, solid liquid ratio 1:5, the reducing sugar yield and concentration of cole can reach the maximum value 34.21% and 79.86g/L.The detoxification methods of liquid in the subcritical/supercritical water were improved: The liquid from subcritical/supercritical reaction was excessive neutralized using calcium hydroxide while pH reached 8-9, accurately regulating to 5.0 using phosphoric acid. Then 3% of volume rate of add activated carbon were added in, after stirring for 30 minutes at 50℃and filtered.The influence factors of fermentation of biomass liquefied in subcritical/supercritical water after detoxification to produce ethanol were discussed in this thesis, such as the effect of detoxification and domestication and inoculation volume of Saccharomyces cerevisiae and nutrient content. The results showed that the solution after detoxification was more conductive to fermentation and the ethanol production was improved by 35.6%. The ethanol concentration produced by Saccharomyces cerevisiae after domestication rose from 32g/L to 42.9g/L. The possible reason was that the detoxification inhibiting fermentation of the liquid was incomplete. The best inoculation volume was 10%, the pH reached 5.0 in the end of fermentation. Through the ethanol concentration, the best nutrients ratio are: MgSO₄·7H₂O 0.1g/L, KH₂PO₄ 0.15g/L, （NH₄）₂SO₄ 0.4g/L, and did the verification experiment, the ethanol concentration was 52.6g/L. The bagasse of 20g was liquefied in 343℃, the reducing sugar yield and concentration were 30.4% and 141.55g/L. So 2.09g of reducing sugar were required to produce each gram of ethanol, that was 6.88g of bagasse were required to produce each gram of ethanol. The utilization ratio of reducing sugar was 47.85%. The reducing sugar and ethanol concentration produced by cellulose were 75.94% and 36.12% .更多还原