污泥厌氧消化搅拌条件的优化分析

Optimal Analysis on the Mixing Condition of Sludge in the Process of Anaerobic Digestion

借助实验和计算流体力学方法对污泥厌氧消化的混合效果及能耗进行实验和模拟分析,研究结果表明:对含水率为95%的污泥进行搅拌,随着搅拌转速的增加物料达到混和均匀所需的时间越短,在搅拌转速分别为140、180和220 r/min时,所需搅拌时间分别为40、25和15 min。但是通过功率和能耗比较分析发现转速为180 r/min时的能耗最低;同时利用Fluent软件对该反应器的速度场和浓度场的分布进行了模拟,模拟结果表明随着搅拌转速的增加,反应器内的速度呈逐渐增大的趋势,浓度场分布在转速为180、200和220 r/min时达到均匀,并且基于速度场和浓度场的模拟进行功率和能耗分析的结论和实验结果一致。因此,综合实验和模拟结果,从节能和高效的原则出发确定180 r/min的转速为该反应器混匀时的最佳转速。

Analysis of experiment and simulation on the mixing effect and energy consumption was carried out in the process of sludge anaerobic digestion,with the help of experimental and computational fluid dynamics method. Results show that,for the sludge with the moisture content of 95%,the more stirring speed increases,the shorter time that material needs for mixing evenly. When the stirring speed is respectively 140,180 and 220 r/min,the mixing time needed is 40,25 and15 min,and the power and energy consumption reaches its minimum when the speed is 180 r/min. Meanwhile,a simulation for the distribution of velocity field and concentration field of the reactor by using Fluent software were carried out,which shows that with the increase of stirring speed,the flow velocity in the reactor presents a trend of increase gradually,the concentration field distribution achieve uniform at the speed of 180,200 and 220 r/min. And power and energy consumption analysis according to the results of the simulation are consistent with the experiment. Therefore,the rate 180 r/min is the optimal speed for the reactor under this condition,based on the consideration of the principle of energy saving and high efficient.