【作者】 肖入峰；

【导师】 张建强；

【作者基本信息】 西南交通大学 ， 市政工程， 2012， 博士

【摘要】 目前,环保节能的反渗透膜分离技术已被公认为国际上最具经济效益和社会效益、最具发展前途的高新技术之一。本文采用二级反渗透膜工艺处理维生素C凝结水,制备制药纯化水,主要考查其对水中电导率和TOC的去除效果。阐明反渗透膜系统运行条件对系统性能的影响,寻找一套有效策略确定最优运行工艺参数；确定反渗透膜系统连续处理维生素C凝结水处理效果的预测模型；推导并建立膜透水模型和膜污染模型,研究了最佳清洗时机判断方法,比较并确定最优清洗方式方法。通过对某制药集团维生素C公司的现场调研,确立了研究对象与主体处理工艺技术。为实现处理水质达到制药纯化水要求,深入分析了不同工艺参数(温度、压力、回流比、pH)下,反渗透膜处理VC凝结水系统回收率、脱盐率以及TOC去除率的变化规律,定量研究了各个工艺参数指标对产水指标体系的影响程度,在此基础上采用多元线性回归模型及多元二次回归正交旋转组合模型进行膜工艺的二次优化,为膜法工艺的最优化提供了一套理论方法。二级反渗透运行结果表明,终端产水水质电导率和TOC均达到欧洲药典2000版对制药纯化水的标准。为了保证反渗透膜系统产水水质的稳定,需要对反渗透膜分离过程实时控制。为此通过人工神经网络和多重多元回归将脱盐率与TOC去除率和进水水质及操作参数关联,建立了关于脱盐率与TOC去除率的预测模型。BP神经网络三种预测指标的皮尔逊相关系数都在0.95以上,数据拟合情况良好,相对误差小于5%的预测占到90%以上,最大相对误差为4.75%,最大的平均相对误差为1.52%,完全满足工程上10%的误差要求。同时建立的多重多元回归预测模型产水监控指标的预测误差平方和(PRESS)均小于5%,特别是针对产水回收率的残差为0。R2p进一步显示该模型对产水回收率y、脱盐率R和TOC去除率q的预测能力都达95%以上。针对反渗透膜处理维生素C凝结水,探讨了反渗透膜吸水性能机理、去除小分子有机酸的分离机理和表面氯化降解的机理。从唯象观点出发将反常扩散理论引入反渗透膜固液分离过程,基于随机游动理论导出了整个扩散区的扩散方程和动态吸附初期的吸附方程,研究了水分子在反渗透膜的动态吸附传递规律。基于不可逆热力学模型(S-K模型)、细孔模型(SHP模型)和固定电荷模型(TMS模型),研究了反渗透膜系统工艺参数(温度、压力和pH)对膜结构参数(膜孔半径、孔隙率、膜体积荷电密度等)的影响,进而深入了解膜分离有机酸的机理。分析了反渗透膜处理维生素C凝结水的膜污染机理,并对膜污染控制策略进行了研究(包括清洗时机和清洗方式)。基于临界通量理论,求得发生膜污染的临界通量介于1.1L/(m2·min)到12L/(m2·min)之间。在此基础上,提出了斜率变点分析法用于判断清洗时机,发现最佳的清洗周期为10-15d之间。进而考察不同清洗方式的清洗效果,加强型清洗策略EFM(Enhanced Flux Maintenance)的操作是针对不可逆膜污染的一种有效清洗方式,EFM操作执行起点选择通量衰减5-25%为宜,EFM持续30分钟,0.1%NaClO和025%NaOH都是有机污染的有效清洗剂,膜的平均恢复率分别为93.3%和81.6%。更多还原

【Abstract】 At present, membrane separation technology of environmental protection and energy saving has been recognized as the most international economic and social benefits, and one of the most promising high-tech. This topic using reverse osmosis technology deal with vitamin C condensate for the preparation of pharmaceutical purified water, the main test of the water conductivity and TOC removal efficiency.The purpose are to clarify the impact of the reverse osmosis system operating conditions on system performance, to find an effective strategy to determine the optimal running conditions; to determine the soft control of the reverse osmosis system in order to lay the foundation for the implementation of optimal control; derivation and the establishment of the membrane permeable model and membrane fouling model to find an effective strategy to determine the optimum cleaning time; to compare and determine the optimal cleaning method.By investigating the Northeast General Pharmaceutical Factory vitamin C workshop site the object of study and the main processing technology were established.In order to achieve the purification of the wastewater quality to pharmaceutical pure water standard, in-depth analysis of the different operating conditions (temperature, operating pressure, the reflux ratio and pH), variation on system recovery, desalination rate and TOC removal efficiency, quantitative studying on various operating conditions on the degree of influence of the index system of the water production.On this basis, using multiple linear regression model and multiple quadratic regression orthogonal rotation combination model quadratic optimization of membrane processes, providing a set of theoretical methods for the optimization of membrane processes.In order to guarantee the stability of the control system, the implementation of predictive control and real-time optimization is needed for membrane separation process. Against to reverse osmosis membrane systems, artificial neural networks and multiple multiple regression models were built to predict the water recovery and desalting rate, and connected the recovery, desalination rate and water quality and operating parameters for the basis of the process modeling of soft sensors.The pearson correlation coefficients of three predictors on BP neural network are above0.95, data fitting is good, the relative error of less than5%of the forecast accounts for more than90%, and the maximum relative error is4.75%, the maximum average relative error for1.52%, to fully meet the10%error in the engineering requirements. At the same time prediction error sum of squares of the multiple multiple regression prediction model (PRESS) were less than5%, especially for residual of permeate water recovery rate is0. R2P further indicates that predictive ability of the model more than95%about penetration of the water recovery rate y, the desalination rate R and the TOC removal q.Next for the typical commercial crosslinked aromatic polyamide composite reverse osmosis membrane:the LP2521, the mechanism of water absorption, the separation mechanism of removal small molecule organic acids, and the degradation mechanism of surface chloride were explored. From the phenomenological point of view, introduction the theory of anomalous diffusion into the solid-liquid separation process of reverse osmosis membranes, the diffusion equation in the diffusion zone and the initial adsorption equation of the dynamic adsorption were derived based on the random walk theory, studied the dynamics adsorption of water molecules in the reverse osmosis membrane.Based on irreversible thermodynamics model (SK model), the pore model (SHP model) and the fixed charge model (TMS model), the influence on the membrane structure parameters (the membrane pore radius, porosity the membrane volume density of charged, etc.) by the reverse osmosis system operating conditions(temperature, pressure and pH) were studied, and thus depth understanding of the separation mechanism of membrane for organic acids.In order to achieve industrialization, analysis of the mechanism of membrane fouling in reverse osmosis membrane treatment of vitamin C condensate, and membrane fouling control strategies were studied in detail (including the cleaning time and cleaning method).Based on the critical flux theory, the produce membrane fouling critical flux was seeked between1.1L/(m2·min) between the1.2L/(m2· min). On this basis, the slope change point analysis method was used to determine the cleaning time, and found the best cleaning cycle for the10-15d. And then examine the cleaning effect of different ways, the enhanced cleaning strategies EFM (Enhanced Flux Maintenance) operation is an effective cleaning method for irreversible membrane fouling. The EFM operation is performed starting at the point of the flux decline of5-25%appropriately, and it lasted30minutes.0.1%NaClO and0.25%NaOH is an effective cleaning agent for the organic pollution, the average recovery rate of the membrane were93.3%and81.6%.更多还原