微观尺度有机负荷对水力剪切力的影响研究

Effects of Organic Loading on Hydraulic Shear Force at Micro Scale

厌氧消化由于低成本和能源回收等优点越来越引起广泛关注。为克服大尺度研究动态厌氧过程的不足,基于微反应器和定量图像分析技术定量研究有机负荷对水力剪切力的影响。结果表明:气泡的上升速度v随气泡直径d增大而增大;当培养液COD从2 000mg/L增加到4 000 mg/L时,大气泡(0.20~0.50 mm)的比例从22.78%增加到56.48%,增加了1.48倍。因此,适当增大有机负荷可以显著提高气泡中大气泡的比例和气泡的上升速率,从而提高溶液的水力剪切力,强化产沼气。

Anaerobic digestion is attracting more and more interests because of its advantages such as low cost and recovery of clean energy etc. In order to overcome the drawbacks of the existed methods to study the dynamic anaerobic process, a novel microscopical quantitative approach at the granule level was used to study the effect of organic loading to hydraulic shear force combining both the microdevice and the quantitative image analysis techniques. It shows that as the COD of the culture solution rose from 2000 mg/L to 4000 mg/L,the percent of big bubbles has risen 1.48 times, from 22.78% to 56.48%.With the increasing of the equivalent diameter, the velocity of the bubble increased. So the adequate increasing of the organic loading can improve the percent of big bubbles causing the velocities of the bubbles increasing. Thus the hydraulic shear force improves, leading to the enhancement of anaerobic biogas production.