本文選題：過程控制　切入點：PCS7系統(tǒng)　出處：《東華大學》2017年碩士論文

【摘要】：聚氯乙烯(PVC)因其在大分子中引入氯原子,使其在耐燃、透明、耐折和力學性能等方面均超過了聚乙烯,是世界五大通用熱塑樹脂之一。聚氯乙烯的生產(chǎn)具有很強的連續(xù)控制性,因此需要操作和調(diào)節(jié)的變量也很多,同時根據(jù)聚氯乙烯生產(chǎn)的工藝需求,現(xiàn)場的執(zhí)行機構(gòu)會擁有復雜的控制邏輯結(jié)構(gòu)。考慮到聚氯乙烯的生產(chǎn)也會涉及到氯氣這樣有毒有害氣體的配比和傳輸,所以控制系統(tǒng)本身就要具有很高的穩(wěn)定性和靈敏性。溫度的變化是影響聚合度的關(guān)鍵因素,如果溫度不能很好的在生產(chǎn)工藝溫度曲線的范圍內(nèi)進行控制,那么得到的產(chǎn)品就會出現(xiàn)質(zhì)量問題。因此本課題的重點和難點是:如何建立一個關(guān)于溫度的數(shù)學模型;找到一個合適的算法對關(guān)于溫度的數(shù)學模型進行仿真及優(yōu)化,并且證明該算法對溫度達到了理想的控制需求。本論文的主要工作有:首先,對聚氯乙烯的生產(chǎn)環(huán)節(jié)進行簡單的介紹,為建立聚合溫度的數(shù)學模型做了鋪墊;其次,根據(jù)其在聚合反應階段的熱量變化,使用機理建模構(gòu)建溫度變化的數(shù)學模型,該傳遞函數(shù)將會用于對聚合溫度的控制;第三、采用基于免疫粒子群算法的PID參數(shù)整定的方法來控制循環(huán)水閥的開度,從而控制聚合溫度在允許的范圍內(nèi)進行波動。通過MATLAB對傳遞函數(shù)進行仿真后發(fā)現(xiàn),采用免疫粒子群算法的系統(tǒng)動態(tài)性能指標要比整定之前的系統(tǒng)性能指標優(yōu)異。同時將該方法投入實際運行后發(fā)現(xiàn),聚合溫度可以維持在最佳溫度的±0.2℃之內(nèi);第四、對于精細化工行業(yè)的控制,從硬件和軟件設(shè)計的兩個方面入手。在硬件設(shè)計方面,在控制柜中采用了高度的冗余來保證系統(tǒng)的穩(wěn)定性。在軟件設(shè)計方面,通過上位機和下位機的設(shè)計,使軟件部分能夠很好地和硬件部分相融合。由于硬件和軟件實行了高度冗余設(shè)計,所以當PCS7控制系統(tǒng)應用于聚氯乙烯生產(chǎn)的控制過程后,系統(tǒng)的運行穩(wěn)定性比之前有了明顯的提升,在系統(tǒng)發(fā)生故障或者維護設(shè)備時可以使用備用的控制器、現(xiàn)場總線以及服務器等,讓生產(chǎn)過程實現(xiàn)了不停爐操作;第五、在對聚合反應階段的控制方案實施的過程中,通過使用強大的WINCC人機界面,可以很好的了解生產(chǎn)情況,并且可以通過操作員面板對生產(chǎn)環(huán)節(jié)進行相應的干預。通過對聚合反應階段的控制方案的介紹,具體的了解了PCS7控制系統(tǒng)在聚氯乙烯生產(chǎn)中的應用。同時也對生產(chǎn)的各個控制環(huán)節(jié),利用程序進行了說明,并且利用了WINCC的圖形監(jiān)控界面對生產(chǎn)進行監(jiān)控。論文使用PCS7控制系統(tǒng)和免疫粒子群算法對聚氯乙烯的生產(chǎn)進行控制,在投入實際生產(chǎn)后,聚氯乙烯的年產(chǎn)量比之前提升了近一倍,系統(tǒng)的故障率也降低到了0.4/萬爐,對冷卻水的使用率降低了20%,生產(chǎn)整體的反應時間比原來減少的24%,經(jīng)濟效益和產(chǎn)品的質(zhì)量取得了顯著的提高。
[Abstract]:Polyvinyl chloride (PVC) is one of the five universal thermoplastic resins in the world because of its introduction of chlorine atoms in macromolecules, which makes it superior to polyethylene in the aspects of flame resistance, transparency, folding resistance and mechanical properties. The production of PVC has strong continuous control. So there are a lot of variables that need to be operated and adjusted, and at the same time, according to the process requirements of PVC production, The field executive will have a complex control logic structure. Considering that the production of PVC also involves the proportion and transport of toxic and harmful gases such as chlorine, Therefore, the control system itself should have high stability and sensitivity. The change of temperature is the key factor affecting the degree of polymerization. If the temperature is not well controlled within the temperature curve of the production process, So the focus and difficulty of this subject are: how to build a mathematical model about temperature; find a suitable algorithm to simulate and optimize the mathematical model of temperature. The main work of this paper is as follows: firstly, the production of PVC is simply introduced, and the mathematical model of polymerization temperature is established. According to the heat change during the polymerization stage, the mathematical model of temperature change is built by using the mechanism. The transfer function will be used to control the polymerization temperature. The PID parameter tuning method based on immune particle swarm optimization algorithm is used to control the opening of circulating water valve, thus controlling the polymerization temperature to fluctuate within the allowable range. The transfer function is simulated by MATLAB. The dynamic performance index of the system using immune particle swarm optimization algorithm is better than the system performance index before tuning. After putting the method into practice, it is found that the polymerization temperature can be kept within 鹵0.2 鈩，

本文編號：1682971