多模智能控制在造纸厂碱回收系统中的应用研究

发布时间：2018-08-09 07:23

【摘要】：随着经济的发展,人们的生活水平也不断提高,与此同时人们对生活质量的要求也相应提升。其中很重要的一点就是要有一个健康的生活环境。造纸业与我们的生活息息相关,我国已成为世界上生产和消费纸张量最大的国家。但是,造纸业是典型的高污染行业,尤其是造纸过程中产生的大量制浆废液,严重破坏生态环境。造纸厂所排放的废水(黑液)大部分是碱法制浆过程中形成的,所以要从根本上解决废液污染的问题,就必须研究造纸厂碱回收系统。首先,通过对各种黑液处理策略的比较,得出用碱回收法处理黑液是最佳的选择。分析造纸厂碱回收系统的工艺流程,可知闪蒸罐内黑液液位的平稳对碱回收系统的良好运行起着重要的作用。其次,关于黑液液位的控制,传统的控制方法为比例控制或PID控制。但是由于闪蒸罐内的液位具有非线性、时滞性和时变性的特点,所以用传统的控制方法很难取得良好的控制效果。现在模糊控制正在兴起,其具有反应迅速、鲁棒性好等特点。为了取得更好的控制效果,研究人员设计了阈值切换的多模控制器,此种控制器拥有多种控制方法的优点,能较好的实现对黑液液位的控制。但是通过分析阈值切换多模控制器的结构可知,在不同控制模式之间进行切换时必定存在波动干扰。为了取的更好的控制效果,本文提出基于模糊切换的多模控制方法,此方法通过模糊推理判断来实现不同控制模式之间的无差切换。分析闪蒸罐内液位的数学模型,利用MATLAB软件搭建控制模型,并进行黑液液位响应的模拟仿真。仿真结果表明:相比于PID控制和阈值切换的多模控制,使用模糊切换的多模控制方法控制黑液液位能够取得更好的控制效果。最后根据碱回收系统的需要配置相关的软硬件设备。通过USS通信协议为PLC与变频器建立联系,由PLC发送控制指令来使黑液液位保持平衡。将PLC与Win CC建立通信,通过Win CC创建监控界面并仿真。
[Abstract]:With the development of economy, people's living standard has also been improved. At the same time, people's demands for the quality of life are also promoted. One of the important points is to have a healthy living environment. The paper industry is closely related to our life. China has become the largest country in the world and the consumption paper tensor. But paper making is a country. Industry is a typical high pollution industry, especially a large amount of pulping waste liquid produced in papermaking process, which seriously destroys the ecological environment. Most of the waste water (black liquor) produced by paper mill is formed in the process of alkali pulping. Therefore, to solve the problem of waste liquid pollution fundamentally, it is necessary to study the alkali recovery system of paper mill. The comparison of the black liquor treatment strategy shows that the alkali recovery process is the best choice. Analysis of the process flow of the alkali recovery system in the paper mill shows that the smooth liquid level of the black liquid in the flash tank plays an important role in the good operation of the alkali recovery system. Secondly, the traditional control method is proportional control or PID on the control of the liquid level of the black liquor. However, because the liquid level in the flash tank is nonlinear, time-delay and time-varying, it is difficult to achieve good control effect with the traditional control method. Now fuzzy control is rising, which has the characteristics of rapid response and good robustness. In order to achieve better control effect, the researchers designed the threshold switching more. The controller has the advantages of a variety of control methods and can better control the liquid level of the black liquid. But by analyzing the structure of the threshold switching multimode controller, it is known that there must be fluctuation interference when switching between different control modes. In order to get better control effect, this paper proposes a fuzzy handover based on the fuzzy switching. The method of multimode control is used to realize the difference between different control modes by fuzzy reasoning. The mathematical model of the liquid level in the flash tank is analyzed. The control model is built by the MATLAB software and the simulation of the liquid level response of the black liquid is simulated. The simulation results show that the phase is compared with the multimode control of the PID control and the threshold switching, and the use of the model is used. The fuzzy switching multimode control method can control the liquid level of the black liquid to achieve better control effect. Finally, the related software and hardware equipment should be configured according to the needs of the alkali recovery system. Through the USS communication protocol, the PLC is connected with the inverter, and the control instruction is sent by PLC to balance the liquid level of the black liquid. The communication between PLC and Win CC is established through Win CC. Create a monitor interface and simulate it.
【学位授予单位】：兰州理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TS736;TP273

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