pH值对苦荞渣厌氧发酵性能的影响

doi:10.3969/j.issn.1673-5854.2021.05.006

摘要/Abstract

摘要：

以苦荞渣为原料，设置不同总固体（TS）质量分数的发酵液进行厌氧发酵，探究TS质量分数对发酵产气量及发酵液酸化的影响。并通过对发酵液添加缓冲溶液探究整个厌氧发酵过程中挥发性脂肪酸的变化情况。结果表明：当TS质量分数为4%时，产气情况良好；当TS质量分数超过4%时，系统就会发生酸化，酸化的原因是由于过量的丁酸积累所导致。通过使用缓冲溶液（30% NaOH溶液）调节pH值进行联合产氢产甲烷联合发酵，可促进丁酸向乙酸的转化，有效解决酸积累问题并提高能源转化效率。相同TS质量分数下，产氢产甲烷联合组（4^#和5^#）的能源转化效率分别是未处理组（2^#和3^#）的10.8倍和12.8倍。酸化后使用缓冲溶液调节pH值不仅可以快速恢复产气，恢复产气率也相比其他恢复方式的产气率更高，TS产气率达到1 267 mL/g。使用Modified Gompertz方程进行拟合发现，相关系数（R）均在0.99以上，拟合结果较好。

关键词: 苦荞渣, 厌氧消化, 酸化, 产氢产甲烷, 挥发性脂肪酸

Abstract:

Tartary buckwheat residue was used as raw material, and the fermentation broth with different total solid (TS) mass fraction was used to investigate the acidification experiment. After obtaining the mass fraction of acidified TS, it was readded with buffer solution for anaerobic fermentation. The changes of volatile fatty acids in the whole process of anaerobic fermentation were monitored. The results showed that when the mass fraction of TS was 4%, the gas production was good.When the mass fraction of TS exceeded 4%, acidification occurred in the system, which was caused by excessive accumulation of butyric acid. The conversion of butyric acid to acetic acid could be promoted by using buffer solution(30% NaOH solution) to adjust pH value for combined hydrogen and methane production fermentation, which could effectively solve the problem of acid accumulation and improve energy conversion efficiency. Under the same TS mass fraction, the energy conversion efficiency of the combined hydrogen and methane production group (4^# and 5^#) were 10.8 times and 12.8 times of those of the untreated group (2^# and 3^#), respectively. Adjusting pH value with buffer solution after acidification not only could quickly restore gas production, but also had a higher gas production rate than other recovery methods, and the gas production rate of TS could reach 1 267 mL/g. Modified Gompertz equation was used for fitting, and it was found that the correlation coefficients R were all above 0.99, and the fitting results were good.

Key words: tartary buckwheat residue, anaerobic digestion, acidification, hydrogen and methane production, volatile fatty acid

中图分类号:

TQ35
S216.4

曾静, 杨红, 刘士清, 尹芳, 张无敌. pH值对苦荞渣厌氧发酵性能的影响[J]. 生物质化学工程, 2021, 55(5): 35-41.

Jing ZENG, Hong YANG, Shiqing LIU, Fang YIN, Wudi ZHANG. Effect of pH Value on Anaerobic Fermentation Performance of Tartary Buckwheat Residue[J]. Biomass Chemical Engineering, 2021, 55(5): 35-41.

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样品 sample	水分¹⁾/% moisture	灰分/% ash	粗纤维/% crude fiber	粗脂肪/% crude fat	粗蛋白/% crude protein	无氮浸出物/% nitrogen-free extract	低位热值/(J·g^-1) calorific value
黑苦荞black tartary buckwheat	8.79±0.13	1.99±0.12	1.15±0.21	1.74±0.22	11.05±0.36	75.28±3.64	17033±65
黑苦荞渣black tartary buckwheat residue	72.42±1.42	1.35±0.08	1.41±0.17	1.42±0.15	10.16±0.29	13.24±1.23	17782±53

料液 material	发酵料液中TS/% mass fraction of TS in fermentation liquid	苦荞渣添加量/g tartary buckwheat residue addition	污泥接种量/g inoculated sludge quantity	发酵液总体积/mL total volume of fermentation broth	缓冲溶液 buffer solution
1^#	4	9.55	160	400	无添加no added
2^#	5	24.06	160	400	无添加no added
3^#	6	38.56	160	400	无添加no added
4^#	5	24.06	160	400	添加added
5^#	6	38.56	160	400	添加added
6^#	3	0	160	400	无添加no added
7^#	3	0	160	400	添加added

原料 raw material	调节方式 adjusting way	研究结果 research results	文献 literature
发酵后的酸化污泥 acidified sludge after fermentation	添加生物炭 add biochar	20 d后恢复活性，TS产气率为312 mL/g the gas production rate of TS was 312 mL/g after 20 days	[10]
城市固体废弃物 municipal solid waste	添加零价铁 add Fe⁰	21 d后恢复产气，VS产甲烷率约为595 mL/g gas production resumed after 21 days, the methane production rate of VS was about 595 mL/g	[23]
餐厨垃圾 kitchen waste	添加钢渣 add steel slag	当天恢复产气，累积恢复产气率为285.33 mL/g gas production resumed on the same day, the cumulative recovery rate 285.33 mL/g	[11]
苦荞渣 tartary buckwheat residue	添加30% NaOH add 30% NaOH	当天恢复产气，TS产气率为1267 mL/g gas production resumed on the same day, TS gas production rate 1267 mL/g	本研究 this study

料液 material	发酵前before fermentation					发酵后after fermentation
料液 material	乙酸/% acetic acid	丁酸/% butyric acid	戊酸/% valeric acid	丙酸/% propionic acid	总酸/(mg·L^-1) total acid	乙酸/% acetic acid	丁酸/% butyric acid	戊酸/% valeric acid	丙酸/% propionic acid	总酸/(mg·L^-1) total acid
1^#	89.38	3.70	5.52	1.40	123	81.95	14.78	0.00	3.27	61
2^#	90.41	3.47	4.10	2.03	133	50.95	47.17	0.09	1.79	13908
3^#	88.86	4.84	5.08	1.22	130	59.04	39.68	0.15	1.13	20473
4^#	90.48	4.13	3.97	1.42	177	85.35	11.88	0.00	2.77	49
5^#	86.90	6.06	4.71	2.33	135	94.65	3.60	0.00	1.75	112

组别 group	累积产气量/mL cumulative gas production	最大产气速率/(mL·h^-1) maximum gas production rate	发酵滞留时间/h residence time	TS产气率/(mL·g^-1) TS gas rate	VS产气率/(mL·g^-1) VS gas rate	相关系数 correlation coefficient
1^#	3182	11	12.48	1208	1224	0.9959
2^#	1635	94	1.33	246	250	0.9986
3^#	2417	131	1.28	227	230	0.9965
4^#产氢阶段 hydrogen production stage	3418	140	0.05	515	522	0.9930
4^#产甲烷阶段 methane production stage	4931	18	31.68	743	753	0.9957
5^#产氢阶段 hydrogen production stage	5734	188	0.05	539	546	0.9950
5^#产甲烷阶段 methane production stage	8001	24	39.36	752	762	0.9925