基于S-200PLC的精馏温度控制系统的毕业设计(论文)

基于S-200PLC的精馏温度控制系统 洛阳理工学院毕业设计（论文）

基于PLC的工业精馏控制系统

摘 要

精馏是石油、轻工、化工等生产过程中，常常需要将原料、中间产物或粗产品中的组成部分进行分离，最常用的方法。精馏分离是根据溶液中各组分挥发度或沸点的差异，使各组分得以分离。精馏是化工过程中的核心组成部分，而对于精馏过程控制来说温度的控制是重中之重，剧烈的温度变化会导致分离组分离提纯度降低，对精馏的效率影响极大，甚至导致精馏塔无法正常运行以及设备的损坏。

本设计硬件方面采用了西门子S7-200系列CPU型号为226的PLC、K型热电偶和温度模EM231。热电偶作为温度的采集元件，采集的信号经过EM231的处理后就可把数据送入PLC中进行处理。PLC的程序中采用了位置式PID算法，实现温度的自动控制。使PID控制更为灵活, 较好地满足了生产过程的要求。用WINCC上位机和西门子S7-200 PLC下位机组成一个稳定的温度控制系统，以达到温度控制的目的，初始时给系统一个设定值，一旦温度偏离设定值，热电偶采集到后把温度变化转变为电信号传递到PLC中，PLC会发出信号使精馏塔内电阻加热丝，使其增加或减小功率，使温度达到设定值。实际运行结果验证了PLC应用于精馏塔温度控制系统的可行性及精确性。

关键词：可编程控制器，温度控制，WINCC上位机，PID控制

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基于S-200PLC的精馏温度控制系统 洛阳理工学院毕业设计（论文）

Industrial distillation tower based on PLC control system

ABSTRACT

Distillation is the petroleum, light industry, chemical industry production process, often need to be raw materials, intermediate products or the crude product components were separated, the most commonly used method. Distillation separation is based on the solution of volatile components in degree or boiling point difference, make each allocated to separate. Distillation is the process of the core components, and for the distillation process control, temperature control is the most important, sharp temperature change causes the separated group separation purity decreasing, the rectification efficiency greatly, and even lead to the normal operation of distillation tower and equipment damage. While the PLC has high reliability, easy programming, easy maintenance and other advantages, can be widely used in various control systems, so for the distillation process control special decided to use PLC to achieve temperature control for distillation system utility. In the rectifying tower temperature system is complicated in structure and accuracy requirements higher characteristic, adopts Siemens S7-200programmable controller PLC on system temperature system. As a result of distillation column temperature lag time constant and the inertia time constant was bigger, used to separate the single loop feedback control system, easy to cause larger oscillation, so the actual is used in cascade control and cascade control main controller adopts the integral separation PID control scheme. At the same time, the single parameter fuzzy PID control and programmable controller logic instructions to combine, the PID control more flexible, to better meet the requirements of the production process. Using WINCC PC and Siemens S7-200PLC machine consists of a stable temperature control system, has reached the purpose of temperature control, once the temperature does not reach the set value, monitoring software to monitor out, send a signal to transfer to the PLC for the control of a distillation column motor speed, which increases or decreases the speed, the temperature reaches set value. The actual operation

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基于S-200PLC的精馏温度控制系统 洛阳理工学院毕业设计（论文）

results showed that PLC is applied to the distillation column temperature control system feasibility and accuracy.

KEY WORDS: programmable logic controller，temperature control，WINCC PC， PID control

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基于S-200PLC的精馏温度控制系统 洛阳理工学院毕业设计（论文）

目 录

前 言 ................................................................................................ 1 第1章 绪 论 .................................................................................... 2

1.1精馏塔的发展过程 ................................................................ 2

1.1.1精馏塔简介 .................................................................. 2 1.1.2精馏塔的发展过程 ...................................................... 2 1.2自动化技术在精馏塔控制系统中的应用。 ......................... 5

1.2.1自动化技术概况 .......................................................... 5 1.2.2精馏过程的控制目标 .................................................. 5 1.2.3精馏过程的基本自动控制 ........................................... 7 1.3论文选题的目的和意义 ........................................................ 8 1.4论文的主要工作和技术线路................................................. 9

1.4.1论文主要工作 .............................................................. 9 1.4.2论文技术路线 ............................................................ 10

第2章 精馏温控系统工艺流程 ..................................................... 11

2.1精馏温控系统原理 .............................................................. 11 2.2温控系统的工艺流程 .......................................................... 14 第3章 精馏系统的硬件设计 ......................................................... 16

3.1硬件配置 .............................................................................. 16

3.1.1 PLC的选择 ................................................................ 16 3.1.2 热电偶 ....................................................................... 20 3.1.3 EM 231模拟量输入模块 ........................................... 20 3.2 I/O分配表和硬件连接图 .................................................... 21 第4章 温控系统软件设计 ............................................................. 23

4.1编程软件的功能及选用 ...................................................... 23 4.2 PID控制算法描述 ............................................................... 26 4.3程序流程图及程序 .............................................................. 29

4.3.1程序流程图 ................................................................ 29 4.3.2程序 ............................................................................ 31

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