全混式厌氧反应器搅拌方式分析与优化

Analysis and Optimization of Different Mixing Method in Completly Mixed Digesters

采用流体动力学模型对全混式厌氧反应器内的流场进行三维稳态数值模拟。研究搅拌器不同安装方式对上层和下层扰动的影响,以达到消除上层结壳和扰动下部污泥层的目的。结果显示,单纯提高搅拌器的安装高度难以改善运行情况。双层搅拌方式下,4.3 m层流速较原始安装位置可提高90.90%,0.2 m层流速可提高20.94%。工程实践表明,改造后的搅拌方式可以有效减少浮渣,同时扰动污泥,提高运行效率。

The characteristics of the flow field in completly mixed biogas digester were studied by computational fluid dynamics（CFD）.Effects of different installation way of agitator to the disturbances in the upper and lower layer were analyzed.The results showed that increasing of agitator mounting height was difficult to improve the flow.Therefore,the double-mixing was used in the biogas digesters.Compared to the original installation,flow speed could increase by 90.90% in the 4.3 m layer and 20.94% in the 0.2 m layer with the double-mixing.The actual project also showed that this modified method could reduce scum,disturb sludge and improve operational efficiency.