Modeling of the Consolidation Stage in Pressure Filtration of Compressible Cakes
Modeling of the Consolidation Stage in Pressure Filtration of Compressible Cakes
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可压缩滤饼压力过滤固结阶段的建模
DOI：
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发表时间：
2002
期刊：
影响因子：
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通讯作者：
P. Scales
中科院分区：
文献类型：
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作者：
P. Kapur;Sashank Laha;S. Usher;Ross G. deKretser;P. Scales
细粒和胶体悬浮液的高压过滤取决于絮凝悬浮液中颗粒网络的结构、其屈服流变性、受阻沉降和通过可压缩多孔介质的流动。一个现实的理论处理的过程中，将相关的材料功能和运输现象，结果在一个非线性偏微分扩散方程的局部固体体积分数与移动边界。由于数值解的复杂性、实验数据的不足以及数值微分中固有的不确定性等原因，模型方程及其近似线性化形式不便于工业高压过滤循环的工程分析。考虑到随着过滤时间的延长，致密层的孔隙度和厚度逐渐减小，流体应力不断下降，提出了滤饼固结阶段的近似模型。该模型更容易实现，似乎能够模拟各种各样的悬浮液具有不同的脱水特性。仅需要一次过滤运行（无需驱动至终点）来估计所用压力的所有模型参数。固结模型是为了补充更详细和严格的扩散模型的白色和同事在这些情况下，数据是有限的，在某种程度上或有不确定性的测量中的脱水参数。由于其相对简单的数学结构，该模型可用于过滤循环的工程分析和模拟，包括面对波动进料特性的基于模型的控制。
High pressure filtration of fines and colloidal suspensions is determined by the structure of particle network in the flocculated suspension, its yield rheology, hindered settling, and flow through the compressible porous media. A realistic theoretical treatment of the process, incorporating the relevant material functions and transport phenomena, results in a nonlinear partial differential diffusion equation for local solid volume fraction with moving boundaries. Because of the complicated nature of numerical solution, deficiencies in the experimental data, and uncertainty inherent in numerical differentiation, among others reasons, the model equation and its approximate linearized version are not convenient for engineering analysis of industrial high pressure filtration cycles. An approximate model of the filter cake consolidation stage is proposed, taking cognizance of the facts that with filtration time the porosity and thickness of the compact bed decrease and the fluid stress drops continually. The model is significantly easier to implement and seemingly capable of simulating a wide variety of suspensions having diverse dewatering characteristics. Only one filtration run, which need not be driven to the end point, is required to estimate all model parameters for the pressure employed. The consolidation model is meant to supplement the more detailed and rigorous diffusion model of white and coworkers in those situations where data is limited in some way or where there is uncertainty in the measurement of the dewatering parameters. Because of its relatively simple mathematical structure, the model could be useful for engineering analysis and simulation of the filtration cycle, including model based control in the face of fluctuating feed properties.