火力发电厂烟气脱硫PLC控制系统设计

火力发电厂烟气脱硫PLC控制系统设计(任务书,开题报告,论文说明书15000字)
摘要
可编程控制系统是一种专门为在工业环境下应用而设计的数字运算操作电子系统。它采用一种可编程的存储器，在其内部存储执行逻辑运算、顺序控制、定时、计数和算术运算等操作的指令，通过数字式或模拟式的输入输出来控制各种类型的机械设备或生产过程。由于它可通过软件来改变控制过程，而且具有体积小、组装维护方便、编程简单、可靠性高、抗干扰能力强等特点，已广泛应用于工业控制的各个领域，大大推进了机电一体化的进程。
我国使用的主要能源是煤炭燃料，所以大气污染以煤烟型污染为主，主要污染物为二氧化硫和烟尘，而二氧化硫正是形成酸雨的主要原因。而火电厂、炼钢厂等工业所排放废气正是大气污染主要来源。
本文介绍了利用可编程控制器编写的一个监测火力发电厂烟气排放浓度的控制系统。检验PLC控制系统的运行情况。主要有PLC控制程序，采集程序和显示程序三块，有效监测火力发电厂烟气脱硫前后的二氧化硫和氮氧化物的浓度。连接PC机与PLC串口通信协议选择Modbus通信协议，Modbus可以支持多种电气接口，如RS-232、RS-485等，还可以在各种介质上传送，如双绞线、光纤、无线等。
实践证明，PLC控制系统在监测烟气浓度中具有良好的应用价值。
关键词：PLC；烟气脱硫；Modbus通信协议；
 
Abstract
PLC system is specially designed for dustrial environment.It is computing operations electronic systems.It uses a programmable memory.It performw logical operations, sequential control, timing, counting and arithmetic operations instruction in its internal storage.It control the various types of machinery or production process by digital or analog input and output.It can change control process by software.It has small volume, assembling, convenient maintenance, easy programming, high reliability, strong anti-jamming capability, etc.It has widely used in various fields of industrial control.
Using coal fuels is the main energy in our country.Atmospheric pollution is given priority to with soot pollution, main pollutants for sulfur dioxide and soot.And sulfur dioxide is the main reason for the formation of acid rain.And coal-fired power plants, steel mills and other industrial emissions is the main source of air pollution.
This paper introduces the use of PLC to write a monitoring control system of coal-fired power plant flue gas emission concentration.It checks the operation of the PLC control system. Mainly include the PLC control program, acquisition program and display three pieces.It monitors the concentration of sulfur dioxide and nitrogen in oxidescoal-fired power plants. Connect the PC and PLC serial communication protocol selection modbus communication protocol. Modbus can support a variety of electrical interface,such as RS-232,RS-485. Transmission can also be in a variety of media,such as twisted-pair cable, optical fiber, wireless, etc.
.Practice has proved that PLC control system has good application value in monitoring the concentration of flue gas.
Keyword: PLC;Flue gas desulfurization, modbus communication protocol

目录
摘要    I
Abstract    II
第一章 绪论    1
1.1课题研究背景    1
1.2课题研究目的及意义    1
1.3 PLC国内外的研究现状与发展趋势    2
1.4本文主要研究内容    4
第二章 硬件选型    5
2.1 PLC的选择    5
2.2 A/D转换器及转换模块    3
2.3文本显示器的选择    4
2.4硬件连线图    5
2.5通信协议的选择    7
第三章 软件部分程序设计    2
3.1开发环境STEP 7 Micro/WIN    2
3.1.1主要功能    2
3.1.2 STEP 7 Micro/WIN 特点    6
3.1.3 S7-200CPU模块与PC机的通讯程序设计    6
3.2主程序框图    8
3.3控制部分程序设计    10
3.4 PLC采集部分程序设计    18
3.5 TD400组态程序    22
第四章 总体调试及结果    32
4.1总体调试及结果    32
结 语    34
参考文献    35
致谢    37