【作者】 王丽丽；

【导师】 梁俊爽；

【作者基本信息】 东北农业大学 ， 农业生物环境与能源工程， 2005， 硕士

【摘要】 由于厌氧技术大多以中温发酵为主,而北方黑龙江省的冬季气温低,所以极大的限制了中温厌氧技术在北方的推广,致使黑龙江省沼气池仍处于家庭户用模式,其产气率低,处理效果差。为加快黑龙江省厌氧技术的发展,本试验在实验室现有的条件下针对牛粪进行了20～30℃的厌氧发酵。通过分析各因素在试验过程中对各指标的影响,探求常温厌氧发酵的变化规律,以便能够为今后的进一步研究提供有力的参考数据。研究内容及成果主要包括以下几个方面: (1) 将料液浓度、温度和污泥量作为影响COD(Chemical Oxygen Demand)去除率、总产气量和产气率的三个主要因素,变化范围分别为4～12%,20～30℃和0～40%。通过二次正交旋转组合试验,得出三因素对各指标的影响方程和变化曲线,并进行方程的检验、优化、频数分析、单因素和双因素分析等。结果表明:各因素之间具有一定的交互作用,不同温度下对应的最佳料液浓度和污泥量有所不同,并且各指标不是随温度的升高逐渐增大,20℃左右的发酵效果比25℃左右的发酵效果好,而30℃下的效果最好。COD去除率、总产气量和产气率达到最优值时所对应的料液浓度、温度和污泥量分别为:(7%,30℃,40%),(11%,30℃,40%)和(6%,30℃,40%); (2) 在试验过程中,通过VFA(Volatile Faty Acid)和PH值的测定,来监测发酵系统的运行状况,研究常温厌氧发酵过程中有机质降解和转化的规律。结果表明:VFA和PH值的变化与各因素的变化密切相关; (3) 根据产气率的优化结果,进行30℃和35℃的对比试验,探讨在料液浓度和污泥量分别为6%和40%的条件下,30℃时能否达到35℃的发酵效果。结果表明:30℃比35℃的总产气量和产气率都高,但COD去除率略低; (4) 在温度和污泥量为25℃和30%的条件下,利用牛粪尿混合液进行料液浓度分别为:2%,4%,6%,8%的对比试验,探讨在沉井中直接进行厌氧发酵的方案是否可行。结果表明:原料中的氨有很强的缓冲能力,能够有效防止系统酸败,当料液浓度为6%时的整体发酵效果较好,与回归分析中产气率的优化结果相同。更多还原

【Abstract】 The temperature of anaerobic fermentation is 35 ℃ mostly, but the air temperature of winter is low in the northern province, Hei Longjiang, so the expansion of anaerobic technique has been restricted tremendously in north. Hitherto, the scale of firedamp production is still placed in the mode of family. The biogas is produced slowly and the result of fermentation is bad. For developing the anaerobic technology quickly in Hei Longjiang province, the experiment of anaerobic fermentation was carried out at 20-30℃ with dairy manure under the condition of laboratory. The influence regulation of each factor to every guideline was analyzed in experimental process and the variety regulation of anaerobic fermentation was investigated in normal temperature in order to provide useful data for the further research of aftertime. The major contents and results included the following four aspects:(1) The three elements of influencing COD removal, the total production of biogas and the ratio of producing biogas were liquid density, temperature and the quantity of microbe. The range were 4~6%,20~30℃,0~40%. Using the orthogonal experiments of rotation assemblage of two times, the effect equations, curves, the optimum and so on. were gotten, and the results were tested, The results suggested that three factors had alternating effects each other; different temperature corresponded to different liquid density and the quantity of microbe; 20℃ corresponded to low quantity of microbe, and 30℃ corresponded to more quantity. The production of biogas was not increased with the raise of temperature, the results of fermentation prefered 20℃ to 25 ℃; and the result of 30℃ was optimal. Three elements of the best COD removal, total production of biogas and the ratio of producing biogas were (7%, 30℃,40%.), (11%, 30℃, 40%), (6%,30℃,40%) .(2) In experimental process, through the survey of VFA and PH, the situation of anaerobic fermentation was monitored. The mechanism of anaerobic fermentation and the regulations of variety were studied. The results showed that the change of VFA and PH was connected with each element tightly.(3) The experimental results of 30℃ and 35℃ were compared in condition of the same liquid density and the quantity of microbe. The liquid density and the quantity of microbe were 6% and 40%. The results showed that the production of biogas at 30 ℃ was high, but its COD removal was low.(4) Under the condition of the same temperature and the quantity of microbe, the experimental results of different liquid density were compared. The experimental material was themixture of.excrment and urine. The liqid density was 2%, 4% 6% and 8% respectively. This experiment studied that the fermentative mechanism of the mixture of manure and urine. The experimental results showed that the ammonia had a good ability of buffer and prevented a quantity of acid in the container of fermentation. The best liquid density was 6%, which was as the optimal results of the ratio of producing biogas.更多还原