Filter Characteristics Research On Deep Dehydration Of Sludge In Van Membrane Filter Press

Abstract:With the large-scale construction of urban sewage treatment plant in our country, 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. The 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-ε 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 simulationSecondly, 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.Fifth, 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 select12mm 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 than10%, 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.This research results can guide the design and use of the van membrane fiiter press.