随着我国城镇污水处理厂的大规模建设,其产生的污泥已成为 新的环境污染源,这些污泥具有高含水率等问题,所以对这些污泥的 深度脱水成为人们重点研究的课题之一。研究发现,对城市污泥经药 剂改性后,用厢式隔膜压滤机对污泥进行深度脱水处理,能形成含水 率低的污泥滤饼,实现污泥减量化。本文应用模拟仿真与实验相结合 的方法,对厢式隔膜压滤机的污泥过滤过程及过滤特性进行了深入的 研究。主要工作如下:
1、建立厢式隔膜压滤机单个滤室的物理模型,在CFD仿真软件 Fluent中采用标准七一占模型、混合模型、多孔介质模型等建立单个 滤室内污泥固液两相流场的数学模型,为固液两相流进行模拟仿真提 供条件、应用上述建立的模型对厢式隔膜压滤机单个滤室内固液两相 流场的速度分布、压力分布、浓度场分布进行模拟仿真,得到了滤饼 两端压降变化规律、滤饼的形成规律以及滤室内污泥两相流的基本流 动规律等;
3、不同过滤压力下的仿真分析。研究了不同过滤压力下滤室中 的速度分布以及形成滤饼的含水率的变化规律;
4、不同进料方式下的仿真分析。对比污泥由滤室中心进料方式 与由滤室上部进料方式,研究其滤饼形成规律以及形成滤饼的均匀 性,结果表明污泥由滤室中心进料方式优于由滤室上部进料方式;
5、最佳滤室厚度的确定。研究了不同滤室厚度下形成的滤饼含 水率以及单位时间滤饼量产率,综合分析发现本研究模型的最佳滤室 厚度为12mm;
6、对厢式隔膜压滤机进行过滤性能实验,并将得到的实验结果 与仿真结果进行对比,发现最大误差在10%以内,验证了仿真结果的 正确性;通过终止进料后进行压榨脱水处理,使得滤饼的含水率进一 步降低,同时,该过程也找到了合适的压榨起始时间点。 论文的研究结果可用于指导厢式隔膜压滤机的设计和使用。
关键词:厢式隔膜压滤机;滤饼含水率;数值模拟;过滤压力;滤室
Abstract:晰m the large.scale construction of urban sewage treatment plant in our COUlltry,sludge generated has become a new source of environmental pollution,which have a high moisture content sludge and other issues,SO the depth of the sludge dewatering become one of these key research topics.111e study found that when the agents modified of urban sludge finished,sludge dewatering depth by Van membrane filter press sludge Can form cake with low moisture content,thus achieving sludge reduction.In this paper,sludge filtration process and filter characteristics of filtration chamber in Van membrane filter press were studied by the method of the numerical simulation combined with experimental validation.The main work is as follows: Firstly,the paper establishes the physical model of single filtration chamber in Van membrane filter press.within fluent of the FLUENT simulation software,using the standard k-s model,hybrid model and porous media models,the mathematical model of the solid—liquid two.phase flow in single filtration chamber of Van membrane filter press has been built,which provided the conditions for the solid-liquid two-phase flow numerical simulation. Secondly,application of the above physical and mathematical models,speed distribution,pressure distribution,concentration field distribution in two-phase flow field of single filtration chamber in Van membrane filter press have simulated and got the changes law in pressure drop across the filter cake,analysed the pattern of filter cake was formed and the basic flow law of sludge two—phase field in filtration chamber, etc.; Thirdly,simulation analysis under different filtration pressures. studing the law of velocity distribution and the moisture content of cake formed under different filtration pressure; Fourth,simulation analysis under different feeding methods. Comparison of sludge from the filter chamber center feeding mode and the upper feeding mode,studying the formation of the cake and the uniformity of cake formed.The results show that the center feed way is better than the upper feed way. FifHl,determine the optimum thickness of filter chamber.studying the moisture content of cake formed and the cake volume yield per unit of time under different thickness of the filter chamber,comprehensive analysis to select 1 2ram as the best filter chamber thickness of the research modle; Sixth,Filter performance test is taken on Van membrane filter press, experimental results obtained are compared with the simulation results, the maximum error iS less than 1 0%,to verify the correctness of the simulation;squeeze dewatering after feed finished,SO further reducing the moisture content of the cake,by experiment to find the right time as the press start point. T】。 search results l research Can guide guide th,de:”g the desima and use of the vailIllS membrane fiiter press. This article has forty—one pictures,seven tables,seventy.one references.