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为解决玉米秸秆干式厌氧发酵系统因乙酸积累而致发酵失败、工程运行不稳定等问题,利用气相色谱仪对玉米秸秆干式厌氧发酵过程中w(乙酸)和w(CH4)进行检测,结合相关性分析和回归分析等方法,研究了乙酸动态产生趋势、w(TS)(TS为总固体)与w(乙酸)的相关性,以及w(乙酸)对CH4产生的作用机制.结果表明:发酵过程中w(乙酸)先增后降,w(TS)由20%增至30%,w(乙酸)增加的持续时间由5 d延至15 d.Pearson相关性分析结果表明,w(TS)与w(乙酸)呈极显著负相关(R<-0.979,P<0.01).一元线性回归分析得到拟合方程y=-1 214.8w(TS)+668.2,由斜率(-1 214.8)可知,w(TS)对产乙酸过程具有较明显的抑制作用.玉米秸秆干式厌氧发酵系统内w(乙酸)为160~451 mg/g,随着w(乙酸)的增加,底物CH4产率经历上升、稳定、下降后再稳定和下降4个阶段,其中w(乙酸)为212~312 mg/g时,底物CH4产率(大于120 m3/t,以秸秆干质量计)最大,其次为w(乙酸)在>312~410 mg/g时的80~120 m3/t.
In order to solve the problem of fermentation failure of corn stalk dry anaerobic fermentation system caused by acetic acid accumulation and instability of engineering operation, w (acetic acid) and w (CH4) were detected by gas chromatography in dry anaerobic fermentation of corn stover , The correlation between w (acetic acid) and w (TS) and the mechanism of action of w (acetic acid) on the production of CH4 were studied by correlation analysis and regression analysis. The results showed that w (acetic acid) firstly increased and then decreased, w (TS) increased from 20% to 30% and w (acetic acid) increased from 5 days to 15 days.Pearson correlation analysis showed that w TS) and w (acetic acid) showed a significant negative correlation (R <-0.979, P <0.01) .The linear regression analysis showed that the fitting equation y = -1 214.8w (TS) It can be seen that w (TS) has obvious inhibition effect on acetic acid production.W (acetic acid) in the dry anaerobic fermentation system of corn stalk is 160 ~ 451 mg / g, with the increase of w (acetic acid) The yield of the substrate increased, stabilized and then dropped down, then stabilized and decreased. The yield of CH4 (more than 120 m3 / t, the dry weight of straw) was the largest when w (acetic acid) was 212-312 mg / g , Followed by w (Acetic acid) of 80 ~ 120 m3 / t at> 312 ~ 410 mg / g.