废弃食用油脂两相厌氧发酵酸化条件优化  

Process optimization of wasted edible oil hydrolytic acidification in two-phase anaerobic digestion

作　　者：贺静[1] 邓雅月 李凛[2] 李政伟[1] 尹小波[1] 邓宇[1] 

机构地区：[1]农业部沼气科学研究所农业部农村可再生能源开发利用重点实验室,成都610041 [2]成都理工大学材化院生物工程系,成都610059

出　　处：《农业工程学报》2015年第19期247-253,共7页Transactions of the Chinese Society of Agricultural Engineering

基　　金：863计划(2013AA102805-02;公益性行业(农业)科研专项(201303099-01);四川省应用基础项目(2015JY0054)

摘　　要：油脂的水解和长链脂肪酸的降解是油脂厌氧发酵过程中的限速步骤,提高水解酸化阶段挥发性脂肪酸(volatile fatty acid,VFA)的产率,有助于后续甲烷化反应的进行。利用响应面方法(response surface methodology,RSM)对废弃食用油脂两相厌氧发酵水解产挥发酸条件进行优化,考察了初始p H值、原料负荷、反应时间和接种量对产生挥发酸浓度的影响,提出采用该工艺的数学模型及优化后的工艺参数。结果表明,各影响因子对挥发酸的影响顺序为:接种量>反应时间>原料负荷>初始p H值,方程的F值为15.65,相关系数为0.9359,调整相关系数为0.8761,说明数学模型可以较好地模拟真实的反应曲面。优化得到最佳的工艺参数为初始p H值6.2、负荷300 g/L、反应时间8 d、接种量40%,在该条件下,实际产挥发酸7 221.0 mg/L,与预测值7 224.0 mg/L吻合且重现性较好。厌氧产甲烷试验表明,酸化后废弃油脂较未酸化油脂在甲烷产量、甲烷含量、总化学需氧量(chemical oxygen demand,COD)去除率及挥发性固体(volatile solid,VS)去除率方面分别提高了44%、11%、28%和51%,经酸化处理比未酸化油脂的厌氧发酵时间(完成一个厌氧发酵周期内总产气量的80%的时间)缩短了28%。该研究结果为废弃食用油脂的两相厌氧发酵中试提供了参考。It was reported that in China the annual consumption of edible oil was 21×106 tons which consequently produced waste oil of about 6×106 tons. The waste oil can be recycled to produce biodiesel, bulk chemicals, surfactant, fine chemicals and biogas. The recycling and bioconversion of waste edible oil into biogas will be beneficial to energy crisis and environmental pollution, and promote sustainable economic development. Because of the suppression of long chain fatty acid that is one of intermediate metabolites, waste edible oil that is directly used in anaerobic fermentation often causes digestion inhibition or system crash. The two-phase anaerobic digestion process can avoid the accumulation of long chain fatty acid and volatile acid in the methanogenesis process. Waste edible oil hydrolysis and long chain fatty acid degradation are critical steps in anaerobic digestion of waste edible oil. Improving the production rate of volatile fatty acid（VFA） in hydrolysis acidification phase will raise the subsequent methanogenesis reaction. The response surface methodology（RSM） can obtain the best combination of the factors in a given area and the optimal value of response values, which has been widely used in the optimization of culture conditions and technology conditions in the areas of food processing, water treatment and so on. Therefore, the RSM was used to optimize waste oil biological hydrolysis to produce volatile acid（including acetic acid, propionic acid and butyric acid）. By adopting the method of central composite design（CCD） line design of experiment, using the soft Design Expert to analyze the experiment result, we established the quadratic polynomial in which volatile acid concentration was taken as the response value. The effects of initial pH value, raw material load, reaction time and inoculation rate on volatile acid concentration were investigated. The mathematical model and optimized parameters of process were also acquired. The results showed that the effects of different factors o

关 键 词：油脂 发酵 甲烷 两相厌氧消化 水解酸化 响应面法 

分 类 号：X712[环境科学与工程—环境工程]