城市供水水处理系统的建模、控制与运行优化研究

发布时间：2018-05-16 01:05

本文选题：混凝投药 + 改进差分进化算法　；参考：《华南理工大学》2013年博士论文

【摘要】：城市供水水处理系统作为一个城市的生活基础设施，其供水质量关系到居民的身体健康，混凝沉淀和过滤作为水处理系统的关键工序，其中水的混凝效果及滤池工况既决定出水质量还影响制水成本。因此，对水处理系统建模，控制与运行优化进行深入研究,在保证供水质量安全的同时尽可能降低能耗是十分有意义的研究课题。在相关科研项目的支持和广东某水厂的协助配合下，对水处理系统的建模、控制与运行优化进行了四方面的研究，主要研究内容和取得成果如下： 1．对混凝投药进行了建模研究，建立了三种不同结构的数学模型。针对目前国内绝大部分水厂投药量由人工经验确定的不足，建立了一种简化适用的投药指数模型，提出了一种改进的差分进化算法，并用该算法来辨识指数模型中的参数；结合现有水厂的实际投药方法，，建立了一种投药分段线性模型，该模型以源水浊度变化分区间，以源水浊度、源水流量为前馈量实现投药粗调，以待滤水浊度为反馈量实现投药细调；最后建立了一种性能较优的神经网络模型。各自的模型检验结果表明得到的三种模型较为准确，可利用其计算结果指导现场操作人员投药，减少生产过程投药的盲目性，确保了待滤水浊度的稳定。 2．对混凝沉淀过程的控制算法进行了分析，研究了几种控制算法并对其做了仿真分析。针对对象模型不易获取，提出了两种改进的PID算法：基于改进差分辨识的PID(MDE-PID)和基于迭代反馈的二自由度PID(IFT-PID)。MDE-PID算法中采用了一种根据个体适应值优劣来变异的改进策略，仿真结果表明该算法可以提高收敛速度和收敛精度。IFT-PID算法对迭代步长更新作了适当改进以确保获得解的准确性，仿真结果表明该算法辨识得到解比其它传统方法更优。针对对象受扰因素多和大滞后特性，提出了两种新的控制算法：基于Smith模型预估的双控制器控制和基于迭代反馈的内模控制(IFT-IMC)。Smith模型预估的双控制器方案将Smith的模型补偿优点和双回路的独立性控制优点结合起来，并对跟踪PI控制器进行非线性补偿。仿真结果表明此算法具有较好的自适应能力和稳定性，可实现对大滞后、干扰多的复杂系统的良好控制。IFT-IMC算法集合了内模控制鲁棒性强和IFT自适应强的优点，具有较好的自适应性和鲁棒性，控制性能优于IMC-PID和Smith-PID，可用于实现对此类难控系统的有效控制。 3．对滤池水头损失和比沉积变化进行了实验研究，建立了滤池水头损失和比沉积两种数学模型。针对过滤过程中水头损失不易求取和比沉积无法获得的不足，建立了水头损失数学模型和比沉积数学模型。首先根据实验数据求取了不同滤层深度水头损失值，给出了水头损失随滤层深度变化的指数关系式以及一种新的水头损失与比沉积的定量关系式，求取了不同滤层深度比沉积。然后借助获得的关系和现有文献结果，给出了水头损失和比沉积随各种影响因素之间的关系式。最后借助获取的水头损失数据和比沉积数据，采用改进差分方法辨识各自模型参数，建立了水头损失模型和比沉积模型，各自的模型检验结果表明，求得的两种模型是准确的。借助两种模型可以从水头损失宏观角度和比沉积微观角度了解滤层堵塞情况，从而更好的设置过滤周期。 4．建立了最优待滤水浊度数学模型，并对滤池过滤和反冲洗进行了运行优化实验研究。从总能耗角度出发，给出了能耗最低时的最优待滤水浊度具体表达式，采用回归辨识法获得了表达式中的未知参数，从而建立了最优待滤水浊度数学模型，证明了现有研究成果中定性提出的最优经济浊度概念的存在性。分析了课题水厂滤池的目前运行工况，提出了两种优化实验方案，并对滤池优化前后的水头损失做了对比分析，实验结果表明，本文提出的优化结论是合理的，实施该优化方案，可以比较明显地降低能耗，具有较好的经济效益和社会效益。最后在总结本文研究的基础上，对水处理系统中建模与控制技术的今后发展及联合优化运行方面进行了展望。
[Abstract]:The urban water supply water treatment system is the living infrastructure of a city. The quality of water supply is related to the health of the residents. Coagulation and sedimentation and filtration are the key processes of the water treatment system. The coagulation effect of water and the working condition of the filter not only determine the quality of water, but also affect the production of water. Therefore, the modeling, control and transportation of the water treatment system are established. It is a very meaningful research topic to optimize the research and ensure that the quality and safety of water supply can be reduced as much as possible.
With the support of relevant scientific research projects and the assistance of a water plant in Guangdong, four aspects of the modeling, control and operation optimization of the water treatment system are studied. The main contents and achievements are as follows:
1. the modeling of coagulant dosage was studied, and three mathematical models with different structures were established.
In view of the shortage of artificial experience in the vast majority of water plants in China, a simplified and applicable drug index model is set up, an improved differential evolution algorithm is proposed, and the algorithm is used to identify the parameters in the index model, and a piecewise linear model is established by combining the actual dosing methods of the existing waterworks. The model takes the turbidity of the source water between the zoning, with the turbidity of the source water, the flow of water as the feedforward, and the fine tuning of the dosage for the feedback of the turbidity of the water. Finally, a neural network model with a better performance is established. The results of the respective model tests show that the three models are more accurate, and the results can be used to indicate the results. Guide the field operators to reduce the blindness in the production process and ensure the stability of the turbidity of the filtered water.
2. the control algorithm of coagulation sedimentation process is analyzed, several control algorithms are studied and simulated.
Two improved PID algorithms are proposed for the object model, which is based on the improved differential identification PID (MDE-PID) and the two degree of freedom (IFT-PID).MDE-PID algorithm based on iterative feedback. A modified strategy based on the individual adaptation value is adopted. The simulation results show that the algorithm can improve the convergence speed and convergence. The precision.IFT-PID algorithm improves the iteration step update properly so as to ensure the accuracy of the solution. The simulation results show that the algorithm is better than the other traditional methods. Two new control algorithms are proposed for the multiple and large lag characteristics of the object disturbance: the dual controller control based on the Smith model and the superposition based on the superposition. The dual controller scheme of the generation feedback internal model control (IFT-IMC).Smith model predicts the advantages of the model compensation of Smith and the advantages of the dual loop independence control, and performs nonlinear compensation for the tracking PI controller. The simulation results show that the algorithm has good adaptive energy and stability, and can realize large lag and much interference. The good control.IFT-IMC algorithm of complex system combines the advantages of strong internal model control and IFT self-adaptive. It has good adaptability and robustness, and the control performance is better than IMC-PID and Smith-PID. It can be used to effectively control this kind of hard control system.
3. the experimental study on the head loss and the change of specific deposition of the filter has been carried out. Two mathematical models of head loss and specific deposition have been established.
A mathematical model of water head loss and a mathematical model of specific deposition are established to solve the problem that the head loss is not easy to be obtained and the specific deposition can not be obtained during the filtration process. First, the loss value of the water head of different filter layers is obtained according to the experimental data. The exponential relation formula of the head loss with the depth of the filter layer and a new head loss are given. The relationship between the water head loss and the specific deposition with various influence factors is given by means of the obtained relationship and the existing literature. Finally, the parameters of the model are identified by the improved difference method. The water head loss model and the specific sedimentation model have been established. The results of each model test show that the two models are accurate. With the help of the two models, the congestion of the filter layer can be understood from the macroscopic angle of the head loss and the microscopic angle of the deposition, thus the filtering period can be better set.
4. the mathematical model of turbidity of the optimal filter water was established, and the operation optimization experiment of filter filtration and backwashing was carried out.
From the point of view of the total energy consumption, the specific expression of the turbidity of the best treatment water for the lowest energy consumption is given. The unknown parameters in the expression are obtained by the regression identification method, thus the mathematical model of the turbidity of the best treatment water is established, and the existence of the concept of the optimal economic turbidity proposed in the existing research results is proved. Two optimization experimental schemes are proposed in the current operating condition of the filter, and the water head loss before and after the filter optimization is compared and analyzed. The experimental results show that the optimization conclusion proposed in this paper is reasonable. The implementation of the optimization scheme can reduce the energy consumption obviously and have better economic and social benefits.
Finally, on the basis of summarizing the research in this paper, the future development and joint optimization operation of modeling and control technology in water treatment system are prospected.

【学位授予单位】：华南理工大学
【学位级别】：博士
【学位授予年份】：2013
【分类号】：TU991.2;TP273

【参考文献】