【作者】 楚莉莉；

【导师】 杨改河；

【作者基本信息】 西北农林科技大学 ， 生态学， 2011， 博士

【摘要】 随着我国能源结构的调整,生物质能以其资源丰富、廉价易得、低碳等优势成为能源的重要组成部分。沼气作为生物质能的一种已被广泛应用于我们的生产和生活中,具有显著的能源、经济和生态效益。厌氧是一个复杂的过程,预处理、接种比例、总固体浓度、原料、温度和外源添加物等因素都对厌氧发酵有显著影响。试验采用可控性恒温发酵装置,模拟沼气池的发酵环境,选取粪便和秸秆为原料,系统的研究了不同预处理、接种比例、总固体浓度、原料、温度和外源添加物对厌氧发酵产沼气的影响,得到如下结论:1.秸秆经生物预处理后,碳氮比下降,5种生物预处理菌剂(微生物催腐剂、腐秆剂、复合菌剂、糖酵酶和沼液)中,沼液的预处理效果最好;糖酵酶的预处理效果最差,在发酵过程中易出现酸化现象。麦秆、稻秆、玉米秆分别经沼液预处理6d、6d、9d后的产气效率最高。2.在中温范围内,各接种比例的干物质产气速率和干物质总产气量随着温度的升高呈先升高后下降的变化趋势;随着接种比例的增加,干物质产气速率和干物质总产气量呈先增大后减小的变化趋势。多元回归分析结果表明,最佳发酵温度为36.6℃,最佳接种比例为发酵原料干重的0.24。3.在发酵温度为40℃时,鸡粪总固体浓度为20%时总产气量最大(17653mL);麦秆总固体浓度为16%时总产气量最大(26855mL);鸡粪与麦秆的混合原料总固体浓度为16%时的总产气量最大(11733mL)。4种总固体浓度下的干物质产气量大小顺序为:8%>12%>16%>20%。4.单一原料中猪粪的产气效率最高,干物质产气量为459.54mL/g;人粪的产气效率最低,干物质产气量仅为144.13mL/g;秸秆中玉米秆的产气效率最高,干物质产气量为216.03mL/g。混合原料中猪粪与麦秆、稻秆、玉米秆配比分别为1﹕1、3﹕1、2﹕1的混合物产气效率最高,干物质产气量分别为为327.4、422.86、413.71mL/g;牛粪与麦秆、稻秆、玉米秆配比分别为2﹕1、2﹕1、1﹕1的混合物产气效率最高,干物质产气量分别为321.72、274.96、308.08mL/g;鸡粪与麦秆、稻秆、玉米秆配比分别为3﹕1、1﹕1、2﹕1的混合物产气效率最高,干物质产气量分别为325.22、296.13、284.47mL/g;人粪与麦秆、稻秆、玉米秆配比分别为2﹕1、2﹕1、1﹕1的混合物产气效率最高,干物质产气量分别为132.56、168.75、126.83mL/g;猪粪、鸡粪分别与麦秆、稻秆、玉米秆配比为1.2﹕0.8﹕1的混合物产气效率最高,干物质产气量分别为252.44mL/g、253.53、247.75mL/g。5.猪粪在30℃时,干物质产气量最大为468.60mL/g;牛粪45℃时,干物质产气量最大为373.91mL/g;鸡粪在50℃时干物质产气量最大为355.28 mL/g;麦秆在50℃时干物质产气量最大为314.79mL/g;稻秆在45℃时干物质产气量最大为364.22mL/g;玉米秆在55℃时干物质产气量最大为355.06mL/g;猪粪麦秆混合原料在55℃时干物质产气量最大为362.19mL/g;猪粪稻秆混合原料在35℃时干物质产气量最大为416.80mL/g;猪粪玉米秆混合原料在35℃时干物质产气量最大为413.71mL/g;牛粪麦秆混合原料在45℃时干物质产气量最大为357.97mL/g;牛粪稻秆混合原料在50℃时干物质产气量最大为345.50mL/g;牛粪玉米秆混合原料在40℃时干物质产气量最大为391.31mL/g;鸡粪麦秆混合原料在45℃时,干物质产气量最大为344.47mL/g;鸡粪稻秆混合原料在45℃时干物质产气量最大为323.59mL/g;鸡粪玉米秆混合原料在50℃时干物质产气量最大,为389.93mL/g。6.添加尿素和纤维素酶可增加沼气的产气量,分别比对照提高2.46%～214.32%和1.63%～104.28%。在进行厌氧发酵时,要选择适宜的接种比例和总固体浓度,当接种比例为0.24、总固体浓度为8%时,产气效率最高。不同发酵原料产气效率不同,单一猪粪原料产气效率最高。以秸秆为主要发酵原料时,用沼液预处理6～9d后,再加入适量的畜禽粪便进行混合发酵,产气效率明显提高;而在混合原料的发酵过程中添加尿素或纤维素酶,可以进一步提高产气效率。温度不同,原料的产气效率亦不同,各种原料适宜的发酵温度范围在30～55℃。因此,农村户用沼气应根据其实际的设施情况和所选的发酵原料,采取相应的保温或加热措施。更多还原

【Abstract】 With the energy restructuring in China, biomass energy with its advantages such as rich resources, cheap and easy to get, low-carbon and so on has been becoming an important part of energy structure. Biogas as one of biomass energy has been widely used in our production and life, which has significant energy, economic and ecological benefits. Anaerobic fermentation require strict anaerobic environment, factors of biopretreatment, inoculum-substrate ratio (ISR), total solid concentration, material, temperature, exogenous additives and so on have significant influence on anaerobic fermentation. In order to simulate biogas fermentation environment, controllable constant–temperature fermented equipment was used, manure and straw was chose as material. Factors that affect the anaerobic fermentation such as biopretreatment, inoculum-substrate ratio, total solid concentration, material, temperature, exogenous additives were studied. The main conclusions indicate that:1. The carbon and nitrogen ratio of straw decreased after biopretreatment. Among the agents of biopretreatment, biogas slurry was best. Biogas slurry was used pretreated wheat straw, rice straw and corn straw, and the optimal pretreatment time was 6d, 6d and 9d.2. At 25～35℃, the TS biogas production rates and TS biogas production yields of each ISR were first increased and then decreased with the increasing of temperature, the TS biogas production rates and TS biogas production yields were first increased and then decreased with the increasing of ISR. Multiple regression analysis predicted, at 36.6℃and the ISR is 0.24.3. At 40℃, when the total solid concentration was 20%, the biogas production yields of chicken manure was highest (17653mL); when the total solid concentration was 16%, the biogas production yields of wheat straw was highest (26855mL); when the total solid concentration was 16%, the biogas production yields of the mixture was highest (11733mL). The order of TS biogas yields was: 8%>12%>16%>20%.4. Single material: the biogas production efficiency of the pig manure was best, the TS biogas yield was 459.54mL/g; the biogas production efficiency of the human excrement was lowest, the TS biogas yield was 144.13mL/g; the biogas production efficiency of the corn straw was better than other straws, the TS biogas yield was 216.03mL/g. Mixture of pig manure and wheat straw, rice straw, corn straw, the biogas production efficiency of 1﹕1, 3﹕ 1, 2﹕1 were highest, the TS biogas yields were 327.46, 422.86, 413.71mL/g, respectively. Mixture of cow manure and wheat straw, rice straw, corn straw, the biogas production efficiency of 2﹕1, 2﹕1, 1﹕1 were highest, the TS biogas yields were 321.72, 274.96, 308.08mL/g, respectively. Mixture of chicken manure and wheat straw, rice straw, corn straw, the biogas production efficiency of 3﹕1, 1﹕1, 2﹕1were highest, the TS biogas yields were 325.22, 296.13, 284.47mL/g, respectively. Mixture of human excrement and wheat straw, rice straw, corn straw, the biogas production efficiency of 2﹕1, 2﹕1, 1﹕1 were highest, the TS biogas yields were 132.56, 168.75, 126.83mL/g, respectively. Mixture of pig manure, chicken manure and straws, the biogas production efficiency of 1.2﹕0.8﹕1 were highest, the TS biogas yields were 252.44, 253.53, 247.75mL/g, respectively.5. The best fermentation temperature of pig manure, cow manure, chicken manure were 30, 45, 50℃, the TS biogas yields were 468.60, 373.91, 355.28mL/g, respectively. The best fermentation temperature of wheat straw, rice straw, corn straw were 50, 45, 55℃, the TS biogas yields were 314.79, 364.22, 355.06mL/g, respectively. The best fermentation temperature of pig manure and straws mixture were 55, 35, 35℃, the TS biogas yields were 362.19, 416.80, 413.71mL/g, respectively. The best fermentation temperature of cow manure and straws mixture were 45, 50, 40℃, the TS biogas yields were 357.97, 345.50, 391.31mL/g, respectively. The best fermentation temperature of chicken manure and straws mixture were 45, 45, 50℃, the TS biogas yields were 344.47, 323.59, 389.93mL/g, respectively.6. Added urea and cellulose can increase biogas production yields, which were increased 2.46%～214.32% and 1.63%～104.28% than control, respectively.ISR and total solid concentration are important factors to anaerobic fermentation, when the ISR is 0.24 and total solids concentration is 8%, biogas production efficiency is highest. Different materials have different biogas production efficiency, and the biogas production efficiency of pig manure is highest. When straw is used as the main fermentation material, biopretreatment and co-digestion with manure can enhance the biogas production efficiency; and add urea or cellulose in mixed material during anaerobic fermentation, can further improve the biogas production efficiency. Biogas production efficiency of material is different at different temperatures, the optimum fermentation temperature rang of materials is between 30～55℃. Therefore, rural household biogas should be take some insulation or heating measures based on the actual situation of the facilities and materials.更多还原