纳米颗粒强化及预处理脱毒促进发酵联产氢气和甲烷

发布时间：2018-06-23 18:01

本文选题：氢气 + 甲烷　；参考：《浙江大学》2016年博士论文

【摘要】：利用生物质为原料通过微生物发酵方法制取氢气是一种环境友好、可再生、低能耗的氢能生产方式。本文以纤维素生物质为重点研究对象,探究了纳米颗粒强化胞间电子传递促进发酵产氢气和甲烷机理,利用硼氢化钠选择性还原醛类抑制物激活并促进暗发酵产氢,揭示了蒸汽稀酸预处理纤维素生物质的微观理化特性,显著提高了生物质暗光耦合产氢以及联产甲烷的能量转化效率。研究了纳米三氧化二铁对产氢菌群微观形态结构及代谢途径的影响机理。三氧化二铁促进了产气肠杆菌细胞间的电子传递和氢酶活性,增强了乙酸代谢产氢途径(C6H1206+ 2H20→2CH3COOH+2C02+4H2↑),弱化了乙醇代谢的竞争途径(C6H1206→2C2H5OH+ 2C02).当添加200 mg/L的纳米三氧化二铁时,葡萄糖和木薯淀粉的发酵产氢率分别提高了17.0%和63.1%,峰值产氢速率分别提高了35.8%和36.4%。纤维素生物质预处理产生了呋喃类(糠醛、5-羟甲基糠醛)和酚类(香草醛、丁香醛)醛基抑制物,导致峰值产氢速率显著降低,产氢峰值时间和迟滞时间显著延迟,实验表明酚类比呋喃类抑制物更显著地抑制了葡萄糖暗发酵产氢过程。原因是醛基在暗发酵中被还原为醇类：R-CHO+2NADH→R-CH20H+2NAD+,大量消耗了氢气生成过程所需的还原力NADH.提出利用硼氢化钠选择性还原呋喃类和酚类醛基有毒抑制物,添加硼氢化钠30 mM对糠醛、5-羟甲基糠醛、香草醛和丁香醛的脱除效率分别达到96.7%、91.7%、77.3%和69.3%,暗发酵产氢率从0显著提高到193.3 mL/g还原糖(产氢恢复率达到99.3%)。硼氢化钠脱除醛基抑制物的还原反应机理为：4R-CHO+NaBH4+2H20→4R-CH20H+ NaB02,避免了醛基抑制物降解对产氢还原力NADH的大量消耗,有效激活并促进了暗发酵产氢反应。首次提出纳米石墨烯促进产氢菌与甲烷菌的种间电子传递以强化暗发酵产甲烷。SEM分析表明添加石墨烯后通过纳米导线强化了产酸菌和甲烷菌之间的物质交换和电子传递。代谢途径分析表明石墨烯促进了产氢菌利用乙醇产乙酸过程(CH3CH20H+H20→ CH3COOH+4e-+4H+)以及甲烷菌利用乙酸产甲烷过程(2CH3COOH→2CH4+2C02),显著强化了产氢菌与甲烷菌的种间电子传递产甲烷(4e-+4H++1/2CO2→1/2CH4+H20)。添加纳米石墨烯1g/L使甲烷产率提高了25.0%,产甲烷峰值速率提高了19.5%。将加热稀酸预处理的猪粪废弃物进行暗光发酵耦合产氢以及联产甲烷。暗发酵产氢率达到71.8 mL H2/g TVS。利用沸石处理暗发酵尾液使过量铵离子抑制物选择性脱除率达到90.6%,然后接种光合细菌得到光发酵产氢率为175.9 mL H2/g TVS。最后接种甲烷菌发酵得到甲烷产率为87.2 mL CH4/g TVS。通过三阶段暗发酵和光发酵耦合产氢气以及联产甲烷,使猪粪的能量转化效率由单纯产氢气的13.7%显著提高至氢气和甲烷联产的29.8%。揭示了木薯渣等纤维素生物质经蒸汽稀酸预处理后的微观理化结构及暗发酵联产氢气甲烷特性。微观测试表明：木薯渣经蒸汽稀酸预处理后产生大量不规则碎片(-23 μm)和部分微孔结构(～6μm),纤维素细胞壁产生明显分层(-0.2 μm),由于无定型结构遭到破坏导致纤维素结晶度由23.7提高到25.9。再经纤维素酶水解后使木薯渣的暗发酵产氢率提高到102.1 mL H2/g TVS,联产甲烷率提高93.2 mL CH4/g TVS。利用50升-500升的中试发酵罐研究了预处理木薯渣的半连续流联产氢气和甲烷,稳定期得到氢气产率为72.0mL/gTVS,甲烷产率为295.4 mL/gTVS。设计了木薯渣联产氢气和甲烷的50001113发酵罐示范工程方案,通过甲烷罐(37℃,pH=7.5)沼液回流为产氢罐(55℃,pH=5.5)补充了大量的产氢酸化菌群,并提供合适碱度避免产氢罐过度酸化,从而实现长期连续稳定地联产氢气和甲烷。
[Abstract]:Using biomass as raw material to produce hydrogen by microbial fermentation is a kind of environmentally friendly, renewable and low energy production hydrogen energy production method. This paper focuses on the research object of cellulose biomass, and explores the mechanism of promoting hydrogen and methane production by enhanced intercellular electron transfer by nano particles, and the selective reduction of aldehydes by sodium borohydride. The system activates and promotes hydrogen production by dark fermentation, reveals the microscopic physical and chemical properties of cellulose biomass pretreated by steam dilute acid, improves the hydrogen production of biomass and the energy conversion efficiency of methane production, and studies the mechanism of the microstructure and metabolic pathways of the nanoscale ferric oxide on the hydrogen producing bacteria. The electron transfer and hydrogenase activity between the cells of Enterobacteriaceae can be promoted, the hydrogen production pathway of acetic acid (C6H1206+ 2H20 to 2CH3COOH+2C02+4H2) is enhanced, and the competitive approach of ethanol metabolism is weakened (C6H1206 to 2C2H5OH+ 2C02). When adding 200 mg/L nanoscale ferric oxide, the hydrogen production rate of glucose and cassava starch is increased, respectively. 17% and 63.1%, the peak hydrogen production rate increased by 35.8% and 36.4%. cellulose biomass pretreatment produced furan (furfural, 5- hydroxymethyl furfural) and phenols (vanillin, Ding Xiangquan) aldehyde inhibitor, which resulted in a significant reduction in the peak hydrogen production rate and a significant delay in the peak hydrogen production time and delay time. The process more significantly inhibits the process of hydrogen production in the dark fermentation of glucose. The reason is that aldehyde groups are reduced to alcohols in dark fermentation: R-CHO+2NADH to R-CH20H+2NAD+, a large amount of reducing force needed to produce hydrogen production process NADH. is proposed to use sodium borohydride to selectively restore furan and phenolic aldehyde group of toxic inhibitor, adding sodium borohydride 30 mM pairs. The removal efficiency of furfural, 5- hydroxymethyl furfural, vanillin and Ding Xiangquan reached 96.7%, 91.7%, 77.3% and 69.3% respectively. The hydrogen production rate of dark fermentation increased from 0 to 193.3 mL/g reducing sugar (the recovery rate of hydrogen production reached 99.3%). The reduction reaction mechanism of sodium borohydride removal of aldehyde inhibitor was 4R-CHO+NaBH4+2H20 to 4R-CH20H+ NaB02, avoiding aldehyde group inhibition. The degradation of the product to the hydrogen reducing force of NADH is a large amount of consumption, which effectively activates and promotes the reaction of hydrogen production in dark fermentation. It is first proposed that nano graphene promotes the interspecific electron transfer of hydrogen producing bacteria and methanogens to strengthen the dark fermentation methane production by.SEM analysis, which indicates that the addition of graphene to the addition of graphene is used to strengthen the material between the acid producing bacteria and the methanogens. The metabolic pathway analysis showed that graphene promoted the use of ethanol producing acetic acid by graphene (CH3CH20H+H20 to CH3COOH+4e-+4H+) and methane producing process (2CH3COOH to 2CH4+2C02) using acetic acid (2CH3COOH to 2CH4+2C02), which significantly enhanced the interspecific electron transfer methane production (4e-+4H++1/2CO2 to 1/2CH4+H20) of hydrogen producing bacteria and methanogens. The nano graphene 1g/L increased the methane yield by 25%, the peak rate of methane production increased by 19.5%., and the pig manure waste pretreated with dilute acid was coupled to hydrogen production and methane production. The hydrogen production rate of dark fermentation reached 71.8 mL H2/g TVS., and the selective removal rate of the excess ammonium ion inhibitor was reached by using zeolite to treat the dark fermented tail liquor. To 90.6%, then inoculated with photosynthetic bacteria, the hydrogen production rate of light fermentation was 175.9 mL H2/g TVS., and methane production was 87.2 mL CH4/g TVS. by inoculation of methanogens, and hydrogen production and methane production were produced by coupling of dark fermentation and light fermentation. The energy conversion efficiency of pig manure was increased from 13.7% of single pure hydrogen to hydrogen and armour. 29.8%. revealed the microscopic physical and chemical structure of cassava residue and other cellulose biomass after the pretreatment of steam dilute acid. The microtest showed that a large number of irregular fragments (-23 mu m) and some microporous structure (~ 6 m) were produced after the pretreatment of the steam dilute acid. Layer (-0.2 mu m), because the amorphous structure was destroyed, the cellulose crystallinity was increased from 23.7 to 25.9. and then by cellulase hydrolysis, the dark fermentation rate of cassava residue was increased to 102.1 mL H2/g TVS. The combined methane production rate increased by 93.2 mL CH4/g TVS. using 50 liters of 50 liters of -500 liters. The semi continuous flow of the pre treated cassava residue was studied. Hydrogen and methane are produced, the yield of hydrogen is 72.0mL/gTVS in the stable period and the methane yield is 295.4 mL/gTVS.. A demonstration project of 50001113 fermentor for hydrogen and methane production by cassava residue is designed. A large number of hydrogen producing acidification bacteria are supplemented by the methane tank (37, pH=7.5) to hydrogen production tank (55, pH=5.5), and the suitable alkalinity is avoided. The hydrogen tank is over acidified so as to achieve long-term continuous and stable production of hydrogen and methane.
【学位授予单位】：浙江大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TQ920.6;TQ116.2;TQ221.11

【相似文献】