论文部分内容阅读
秸秆是重要的沼气工程原料,秸秆预处理对其后续厌氧消化效率影响巨大。采用田间裹包青贮方法,设计3因素正交实验,考察了秸秆含水率、压缩比和添加剂对玉米秸秆发酵时间和厌氧消化产沼气的影响。结果表明:秸秆经过裹包青贮,发酵总时间(total fermentation time,TFT)减少1~2 d,累积产气量达到总产气量的90%所用时间(TFT90%)减少了40%~50%,消化效率明显提高;秸秆含水率对产气效果有明显影响,随着含水率增加,单位总固体(total solid,TS)累计产气量(cumulative biogas yields per TS,CBYT)和沼气日产率(biogas yields rate average day,BYR)由高到低排序为:35%~40%,40%~45%,30%~35%;秸秆压缩比对产气效果有明显影响,随着压缩比的增加,其对CBY和BYR的效应由高到低排序为:185、143与138 kg/m3;添加剂类型对产气效果亦有明显影响,在不同添加剂处理下,其对CBYT和BYR的效应由高到低排序为:尿素处理>甲酸处理>无添加剂处理;正交实验极差分析表明,对CBYT和BYR的影响排序为:含水率﹥压缩比﹥添加剂,其田间裹包青贮进行厌氧发酵的优化组合为:青贮秸秆含水率为35%~40%,压缩比为185 kg/m3,添加剂为营养型,青贮20 d,CBYT和BYR达到最大,分别为646.57 m L/g和173.25 m L/(d·g)。
Straw is an important raw material for biogas projects. Straw pretreatment has a huge impact on its subsequent anaerobic digestion efficiency. Using field wrapped silage method, 3-factor orthogonal experiment was designed to study the effect of straw moisture content, compression ratio and additives on fermentation time of maize stover and biogas production by anaerobic digestion. The results showed that the total fermentation time (TFT) decreased by 1 ~ 2 days and the accumulated gas production reached 90% of the total gas production (TFT90%) by 40% ~ 50% The efficiency of straw moisture significantly affects the gas production. With the increase of water cut, the cumulative biogas yields per TS (CBYT) and biogas yields average day, BYR) ranked from high to low: 35% -40%, 40% -45%, 30% -35%. Straw compression ratio had a significant effect on gas production. With the increase of compression ratio, The effects of CBY and BYR ranked from high to low as 185,143 and 138 kg / m3. The types of additives also had a significant effect on the gas production. Under different additive treatments, the effects of CBYT and BYR were ranked from high to low As follows: Urea treatment> Formic acid treatment> No additive treatment. The range analysis of orthogonal experiment showed that the order of influence on CBYT and BYR was as follows: moisture content> compression ratio> additive. The optimized combination of field wrapped silage for anaerobic fermentation was : Silage straw moisture content of 35% to 40%, the compression ratio of 185 kg / m3, additives for nutrition, silage 20 d, CBY T and BYR reached the maximum at 646.57 m L / g and 173.25 m L / (d · g), respectively.