论文总字数：25141字

摘 要

随着全球日益增进的能源危机，使得生物质能源在国际上备受关注；而我国是农业大国，各类农作物秸秆分布广泛、资源丰富，生物质能源却不能得到合理的利用，是目前我们国家遇到的一大问题。厌氧发酵产沼气是我们国家处理生物质原料最为常见的一种处理方法，目前存在的问题是厌氧发酵的启动缓慢、发酵过程中负荷的变动及其他污染物的存在，导致厌氧发酵体系稳定性差，生产效能低等问题。玉米秸秆作为一种生物质原料富含大量木质纤维，由于玉米秸秆中纤维素、木质素物质难以分解，发酵液中的微生物不稳定，种类又非常复杂，传统的预处理方法降解性差，导致发酵周期长，产气效率低，因此有必要尝试采用更优的预处理方法来提高生物降解性，进一步改善厌氧发酵过程和提高甲烷产量。

有研究表明利用电化学法可以有效的破坏木质纤维素的结构。本实验采用利用电化学调控的方法以提高玉米秸秆厌氧发酵产甲烷效率的研究，通过在厌氧发酵体系中添加外源恒定直流电压，同时在阳极电极附着电化学活性生物膜，在等极板间距的反应条件下探究出电化学对厌氧发酵的调控机理。本实验设计三个实验组，分别为玉米秸秆组（玉米组）、玉米电压组（玉电组）、玉米电压生物膜组（玉电膜组），每组设置三个平行实验组，其中外加电压为0.8 V。并对反应体系的COD浓度、氨氮浓度、阴极电势、日CH₄含量、累积甲烷含量等指标进行测定，得出结果：从日CH₄含量和累积甲烷含量的测定结果可知，产甲烷效率从大到小排列：玉电膜组＞玉电组＞玉米组，从pH值、COD浓度、氨氮浓度的测定结果可知：实验组厌氧发酵体系pH值均呈现先下降后上升的趋势；COD浓度、氨氮浓度整体呈现先上升后下降的趋势；玉电组电势变化要比玉电膜组的电势变化要大。经过研究分析，电化学处理会打断木质纤维素化学键将其降解成小分子物质，电化学氧化会使生物的细胞膜破裂，大分子物质从体内溶出被有效利用降解，进而提高厌氧发酵发酵产甲烷过程。

关键词： 玉米秸秆；厌氧发酵；电化学；甲烷

Study on Electrochemical Regulation of Methane Production by Anaerobic Fermentation of Corn Stalks

Abstract

With the increasing energy crisis in the world, biomass energy has attracted more and more attention in the world, while China is a large agricultural country, where all kinds of crop straws are widely distributed and rich in resources, but biomass energy can not be used rationally. it is a major problem encountered in our country at present. Biogas production by anaerobic fermentation is the most common treatment method for the treatment of biomass raw materials in our country. At present, the existing problems are the slow start of anaerobic fermentation, the change of load in the fermentation process and the existence of other pollutants. It leads to poor stability of anaerobic fermentation system, low production efficiency and so on. As a kind of biomass raw material, corn straw is rich in a large amount of lignocellulosis. because it is difficult to decompose cellulose and lignin in corn straw, the microorganisms in fermentation broth are unstable and complex, and the degradability of traditional pretreatment methods is poor. As a result, the fermentation cycle is long and the gas production efficiency is low, so it is necessary to try to use better pretreatment methods to improVe biodegradability. Further improVe the anaerobic fermentation process and increase methane production.Corn stalk as a biomass raw material is rich in a large amount of wood fiber. Due to the difficulty of decomposing cellulose and lignin in corn stalk, the microorganisms in the fermentation broth are unstable, the types are Very complicated, and the traditional pretreatment method has poor degradability, resulting in fermentation The cycle is long and the efficiency of gas production is low, so it is necessary to try to use a better pretreatment method to improVe biodegradability, further improVe the anaerobic fermentation process and increase methane production.

Some studies haVe shown that the electrochemical method can effectiVely destroy the structure of lignocellulose. In this experiment, the method of electrochemical regulation was used to improVe the methane production efficiency of anaerobic fermentation of corn stalk by adding exogenous constant DC Voltage to the anaerobic fermentation system and attaching electrochemically actiVe biofilm to the anode electrode. under the reaction condition of equal plate spacing, the regulation mechanism of electrochemistry on anaerobic fermentation was explored. In this experiment, three experimental groups were designed, which were corn straw group (corn group), corn Voltage group (corn Voltage group) and corn Voltage biofilm group (corn Voltage biofilm group). There were three parallel experimental groups in each group, in which the applied Voltage was 0.8 V. The COD concentration, ammonia nitrogen concentration, cathodic potential, daily CH4 content and cumulatiVe methane content of the reaction system were determined. The results showed that the methanogenic efficiency was arranged from large to small: Yudian film group amp;gt; Yudian group amp;gt; corn group. The determination results of pH Value, COD concentration and ammonia nitrogen concentration showed that the pH Value of anaerobic fermentation system in the experimental group decreased at first and then increased. As a whole, the concentration of COD and ammonia nitrogen increased at first and then decreased, and the electric potential change of Yudian group was larger than that of Yudian film group. After research and analysis, electrochemical treatment will break the chemical bond of lignocellulose and degrade it into small molecular substances, electrochemical oxidation will break the biological cell membrane, and macromolecular substances will be dissolVed from the body and degraded effectiVely, so as to improVe the methane production process of anaerobic fermentation.

Key words: Corn straw; anaerobic fermentation; electrochemistry; methane

目 录

摘 要 II

Abstract III

第一章 引言 1

1.1 研究背景 1

1.1.1 能源发展与问题 1

1.1.2 生物质厌氧发酵技术 1

1.1.3 秸秆厌氧发酵技术的研究现状 3

1.2 电化学技术 4

1.2.1 电化学技术的原理 4

1.2.2 电化学技术在国内外的研究进展 5

1.2.3 电化学技术调控厌氧发酵过程的研究进展 6

1.3 本课题的研究内容和研究目的意义 7

1.3.1 本课题研究内容 7

1.3.2 本课题的目的意义 7

第二章 材料与方法 8

2.1 实验材料 8

2.1.1 发酵原料 8

2.1.2 电极液组成 8

2.1.3 主要仪器与试剂 8

2.2 实验方法 9

2.2.1 发酵接种物的驯化 9

2.2.2 MFC生物膜的驯化 10

2.2.3 电化学处理装置 10

2.3 探究电化学调控对玉米秸秆厌氧发酵影响的实验设计 11

2.4 实验基本指标测定 11

2.4.1 TS、VS的测定 11

2.4.2木质素纤维素的测定 12

2.5 发酵过程关键指标分析 12

2.5.1 COD与氨氮的测定 13

2.2.2有机酸（VFAs）的检测 13

第三章 结果与分析 14

3.2 实验指标结果分析 14

3.2.1 日产甲烷体积含量 14

3.2.3 发酵体系pH的变化 17

3.2.4 发酵体系COD变化 18

3.2.5 发酵体系氨氮变化 19

3.2.6 发酵体系阴极电势变化 20

第四章 结论与展望 21

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