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摘 要：为了研究水稻秸秆厌氧发酵产沼气特性，提高发酵速率，分别用质量分数为2%、4%、6%、8%的NaOH和CaO溶液对水稻秸秆进行碱性化学预处理，在中温（35±1）℃、水稻秸秆和牛粪按照1:1配比的条件下进行实验。通过比较不同碱预处理对水稻厌氧发酵过程当中的pH值、产气量和甲烷含量所造成的影响，找到最优预处理方法。结果表明，CaO溶液进行预处理的产气量和甲烷含量要明显优于NaOH溶液进行预处理的试验组。从质量分数来说，两组都是6%的优于其他，6% NaOH的累积产气量为18720 mL，TS去除率为53.8%，VS去除率为36.8%，6% CaO的累积产气量为19917 mL，TS去除率为56.3%，VS去除率为38.3%。综合来看，以CaO质量分数为6%的预处理效果最为理想。60017
毕业论文关键词：氢氧化钠，氧化钙，水稻秸秆，沼气，厌氧发酵
Abstract：In order to study the characteristics of biogas production from rice straw by anaerobic fermentation to improve the fermentation rate, respectively, with mass fraction of 2%, 4%, 6%, 8% NaOH and CaO solution on rice straw alkaline chemical pretreatment. After the pretreatment, a batch of experiments of straw were conducted under the condition of (35±1)℃, when the same content of straw and excrement were blended. By comparing the different effects of alkali pretreatment on the anaerobic fermentation process of rice pH value, and the treatment method was selected. The results show that, the CaO solution and the methane content of pretreatment was better than NaOH solution pretreatment of the group. From the mass fraction, the two groups are better than the other 6%, the cumulative gas production of 6% NaOH is 18720 mL, the removal rate of TS was 53.8%, the removal rate of VS was 36.8%, the cumulative gas production of 6% CaO is 19917 mL, the removal rate of TS was 56.3%, the removal rate of VS was 38.3%. Overall, the mass fraction of CaO is the most ideal pretreatment effect 6%.
Keywords：Sodium hydroxide (NaOH), calcium oxide (CaO), rice straw, biogas, anaerobic fermentation
1 引言 6
2 材料与方法 6
2.1 试验材料 6
2.2 试验装置 6
2.3 试验设计 7
2.4 测定项目与方法 7
3 结果与讨论 8
3.1不同碱预处理水稻秸秆厌氧发酵pH比较 8
3.2不同碱预处理水稻秸秆厌氧发酵日产气量和累积产气量比较 8
3.3不同碱预处理水稻秸秆厌氧发酵CH4含量比较 10
3.4不同碱预处理水稻秸秆厌氧发酵TS/VS去除率比较 10
结 论 11
参考文献 13
致 谢 14
1 引言
中国是主要的水稻生产国家，但是这些水稻秸秆资源并没有得到有效利用，大多被随意丢弃和焚烧，造成极大的环境污染和资源浪费。利用水稻秸秆制取沼气，不仅可以解决农村沼气池原料缺乏问题，为在更大规模和更大范围推广沼气提供原材料[1]，还可以从根源上解决秸秆焚烧带来的众多环境问题[2]。
由于秸秆中含有大量难降解的纤维素，半纤维素，木质素等，并且组成结构复杂，主要成分纤维素是结构紧密的结晶体，半纤维素和木质素共价结合，而且纤维素和半纤维素被木质素包裹[3]。木质纤维素不易被微生物降解，如直接用秸秆发酵产沼气，则会出现发酵启动慢、发酵时间延长、产气率低、秸秆利用率低等问题[4]。将秸秆预处理后再发酵，则可提高产气率，缩短启动时间[5]。目前，农作物秸秆预处理方法主要有物理法[6]、化学法[7]和生物法[8]。