隨著我國城鎮污水處理廠的大規模建設,其產生的污泥已成為 新的環境污染源,這些污泥具有高含水率等問題,所以對這些污泥的 深度脫水成為人們重點研究的課題之一。研究發現,對城市污泥經藥 劑改性后,用廂式隔膜壓濾機對污泥進行深度脫水處理,能形成含水 率低的污泥濾餅,實現污泥減量化。本文應用模擬仿真與實驗相結合 的方法,對廂式隔膜壓濾機的污泥過濾過程及過濾特性進行了深入的 研究。主要工作如下:
1、建立廂式隔膜壓濾機單個濾室的物理模型,在CFD仿真軟件 Fluent中采用標準七一占模型、混合模型、多孔介質模型等建立單個 濾室內污泥固液兩相流場的數學模型,為固液兩相流進行模擬仿真提 供條件、應用上述建立的模型對廂式隔膜壓濾機單個濾室內固液兩相 流場的速度分布、壓力分布、濃度場分布進行模擬仿真,得到了濾餅 兩端壓降變化規律、濾餅的形成規律以及濾室內污泥兩相流的基本流 動規律等;
3、不同過濾壓力下的仿真分析。研究了不同過濾壓力下濾室中 的速度分布以及形成濾餅的含水率的變化規律;
4、不同進料方式下的仿真分析。對比污泥由濾室中心進料方式 與由濾室上部進料方式,研究其濾餅形成規律以及形成濾餅的均勻 性,結果表明污泥由濾室中心進料方式優于由濾室上部進料方式;
5、最佳濾室厚度的確定。研究了不同濾室厚度下形成的濾餅含 水率以及單位時間濾餅量產率,綜合分析發現本研究模型的最佳濾室 厚度為12mm;
6、對廂式隔膜壓濾機進行過濾性能實驗,并將得到的實驗結果 與仿真結果進行對比,發現最大誤差在10%以內,驗證了仿真結果的 正確性;通過終止進料后進行壓榨脫水處理,使得濾餅的含水率進一 步降低,同時,該過程也找到了合適的壓榨起始時間點。 論文的研究結果可用于指導廂式隔膜壓濾機的設計和使用。
關鍵詞:廂式隔膜壓濾機;濾餅含水率;數值模擬;過濾壓力;濾室
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.