玉米秸秆梯级利用产丁醇及MEC产氢的研究

发布时间：2018-05-14 21:19

本文选题：玉米秸秆 + 丁醇　；参考：《哈尔滨工业大学》2017年硕士论文

【摘要】：我国是农业大国,每年产生8亿吨的农作物秸秆有30%以上得不到有效利用。秸秆中含有的纤维素和半纤维素是优质的生物质资源。生物丁醇和氢气都是重要的可再生能源,可以应用到能源、交通燃料等领域。纤维素水解成单糖后,可以利用生物法发酵还原糖生产丁醇。采用纤维素类生物质生产生物能源和秸秆的资源化利用已引起了社会各界的广泛关注。微生物电解池(Microbial electrolysis cell,MEC)是一种新兴的生物制氢技术,能够在处理有机废水的同时高效产氢。本实验以秸秆梯级利用为出发点,研究了促进玉米秸秆水解液发酵产丁醇的方法,同时探索了利用MEC利用丁醇发酵废液制氢的可行性,并采用微生物燃料电池(Microbial Fuel Cell,MFC)处理MEC产氢废液,并据此提出了秸秆水解液发酵产丁醇-MEC产氢的提高生物质利用率的方法。本研究通过研究预处理方法、纤维素酶解缓冲溶液和水解液中的抑制物去除方法提高玉米秸秆糖化率。在稀酸预处理、乙酸-乙酸钠缓冲溶液条件下还原糖的浓度为30.90 g/L。石灰法可以有效去除预处理抑制物并比对照组丁醇浓度提高了1.1倍。在秸秆水解液发酵时,添加适量的外源电子载体(苄基紫精、甲基蓝)可以显著提高丁醇的产量。其中,当玉米秸秆水解液中含有20 mg/L的苄基紫精,丁醇的和溶剂的产量分别为6.49 g/L和8.14 g/L,丁醇产率提高到0.41 g/g。MEC利用丁醇发酵废液产氢,不同的发酵废液浓度对最终的产氢量和COD去除效果有较大影响。发酵废液的进水浓度在4272 mg/L时,最大产氢速率为3.58±0.47 m3H2/m3/d,氢气产率为16.34 mmol H2/g COD,库伦效率为111.60±9.11%,此时COD去除率有71.6±2.3%。当外加电压从0.5 V增加到0.8 V时,MEC的最大产氢速率和氢气产率均有提高,0.8 V外加电压条件下COD去除率为70.1±2.41%。采用454高通量测序方法对MEC的阳极微生物进行分析,群落中含有较多的产电菌Geobacter。相比于单一底物乙酸钠运行的反应器,发酵废液中含有葡萄糖、乙酸、丁酸等有机物,以发酵液为底物的MEC微生物群落多样性更高,菌群种类复杂,实际的产氢效果与降解纤维素的产电菌有密切的联系。最后,采用MFC处理MEC产氢废液,考察了MFC阳极微生物的产电特性和COD去除效果。产氢废液的COD浓度为1277±103 mg/L时,在MFC中最大功率密度为0.607 W/m2,此时COD去除率为90.5±2.84%,实现了有机物的利用和同步产电。
[Abstract]:China is a large agricultural country, producing 800 million tons of crop straw every year more than 30% can not be effectively used. Cellulose and hemicellulose contained in straw are high quality biomass resources. Biobutanol and hydrogen are important renewable energy, which can be used in energy, transportation fuel and other fields. When cellulose is hydrolyzed to monosaccharide, butanol can be produced by biological fermentation of reducing sugar. The use of cellulose biomass to produce bio-energy and the utilization of straw has attracted wide attention. Microbial electrolysis cell (microbial electrolysis cell) is a new biological hydrogen production technology, which can produce hydrogen efficiently while treating organic wastewater. In this experiment, the method of promoting the fermentation of butanol from corn straw hydrolysate was studied based on the step utilization of straw, and the feasibility of using MEC to produce hydrogen from butanol fermentation waste liquor was explored. Microbial Fuel cell (MFCs) was used to treat the waste liquid of MEC hydrogen production. Based on this, the method of improving biomass utilization rate was put forward by fermentation of straw hydrolysate to produce butanol -MEC. In this study, the pretreatment method, the removal method of inhibitor in cellulase hydrolysis buffer solution and hydrolysate were studied to improve the saccharification rate of corn straw. The concentration of reducing sugar was 30.90 g / L under the condition of dilute acid pretreatment and acetic acid-sodium acetate buffer solution. The pretreatment inhibitor was effectively removed by lime method and the concentration of butanol was 1.1 times higher than that of the control group. During the fermentation of straw hydrolysate, the yield of butanol was significantly increased by adding appropriate amount of exogenous electron carrier (benzyl violet, methyl blue). When corn straw hydrolysate contained 20 mg/L benzyl violet, butanol and solvent were 6.49 g / L and 8.14 g / L, respectively. The yield of butanol was increased to 0.41 g/g.MEC. The final hydrogen production and the removal efficiency of COD were greatly affected by the different concentration of fermentation waste liquor. At the influent concentration of 4272 mg/L, the maximum hydrogen production rate was 3.58 卤0.47m3H _ 2 / m _ 3 / d, the hydrogen yield was 16.34 mmol H _ 2 / g COD, the Coulomb efficiency was 111.60 卤9.11 and the COD removal rate was 71.6 卤2.3%. When the applied voltage was increased from 0.5 V to 0.8 V, the maximum hydrogen production rate and hydrogen yield were increased. The COD removal rate was 70.1 卤2.41 at 0.8 V applied voltage. The anodic microbes of MEC were analyzed by 454 high-throughput sequencing method. Compared with the reactor run by single substrate sodium acetate, the fermentation waste liquid contains glucose, acetic acid, butyric acid and other organic matter. The microbial community diversity of MEC with fermentation broth as substrate is higher and the species of bacteria is more complex. The actual hydrogen production effect is closely related to the cellulose-degrading electro-producing bacteria. Finally, MFC was used to treat MEC hydrogen production waste liquid, and the electricity production characteristics of MFC anode microorganism and the removal efficiency of COD were investigated. The maximum power density in MFC was 0.607 W / m ~ (2) when the concentration of COD was 1277 卤10 ~ 3 mg/L, and the removal rate of COD was 90.5 卤2.84. The utilization of organic compounds and the simultaneous generation of electricity were realized.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ923;TQ116.2;X712

【参考文献】