中药渣不同有机负荷厌氧发酵工艺参数分析

Effect of organic loading on semi-continuous anaerobic fermentation parameters of Chinese medicinal herb residues

以人参、赤芍和桂皮等混合中药渣为发酵原料,采用全混式厌氧反应器,在中温(35±1)℃,通过半连续厌氧发酵工艺,研究其发酵过程中不同有机负荷,沼气日产气量、甲烷含量、p H值、挥发性有机酸(VFA)和总无机碳(TIC)等参数变化相互关系。结果表明:厌氧消化过程呈现5个阶段,即发酵启动期、增长期、稳定期、超负荷期和恢复期;反应器高效稳定运行可承受的中药渣最大有机负荷为8.0 g TS·(L·d)^(-1),系统p H值稳定在7.0左右,沼气日产气量8.38 L,容积产气率为1.68 L·(d·L)^(-1),原料产沼气能力262 m L·(TS g·d)^(-1),VS去除率为20.69%。有机负荷为10.0 g TS·(L·d)^(-1)时超负荷运行,沼气产量急剧下降,系统运行稳定性被破坏。因此,在中药渣厌氧消化过程中一定要控制有机负荷在最佳数值,实时监测反应器运行过程中的各参数变化,及时做出调整,保证工程的高效稳定运行。

Biogas fermentation of mixed traditional Chinese medicinal herb residues was carried out with ginseng,red peony root,and cassia bark as starting materials in a continuous stirred tank reactor at the temperature of（ 35 ± 1） ℃ to study the semi continuous fermentation process. At different organic loading rates,the correlation and changes of biogas production,methane contents,p H values,volatile organic acids（ VFA）,total inorganic carbon（ TIC）,and other parameters were tested. The results showed that the anaerobic digestion process for Chinese medicinal herb residues could be divided into the following five stages： the starting period,growth period,stable period,super load period,and recovery period. When the reactors were running efficiently and stably,the maximum organic loading rate of the Chinese medicinal herb residues was 8 g TS·（ d·L）^-1,and the p H value was stable at 7. 0,the biogas average production rate was 1. 68 L·（ d·L）^-1,and the VS removal rate was 20. 69%. When the organic loading rate was increased to 10 g TS·（ d·L）^-1,the system was in overload operation mode,and consequently,system stability was destroyed and the biogas production capacity declined rapidly. Therefore,when subjecting Chinese medicinal herb residues to anaerobic digestion,one must control the organic loading rate at the optimal conditions. This can be accomplished by monitoring the various parameters in real-time and making adjustments to ensure efficient and stable operations in the reactor.