基于PLC的造纸废水中段水控制系统设计_自动化专业论文
发布时间：2014-05-15
来源：人大经济论坛
自动化专业论文范文
目 录
摘 要I
ABSTRACTII
1 绪论1
1.1 引言1
1.2 国内外发展状况2
2 方案选定3
2.1 厌氧法3
2.1.1 升流式厌氧污泥反应器（UASB）3
2.1.2 内循环（IC）厌氧反应器3
2.2 SBR+絮凝沉淀法处理中段水4
2.3 好氧处理法5
2.4 方案确定7
3 中段水好氧处理的自动控制8
3.1控制工艺流程8
3.2 液位控制设计9
3.3 进反应器废水温度控制10
3.4 PH控制单元设计11
3.5 营养物质投加控制13
4 硬件部分设计14
4.1 PLC控制系统设计原则和设计步骤14
4.2控制总体要求16
4.3系统硬件配置16
4.4 PLC选型及传感器的连接17
4.5硬件连接图24
4.5.1电气控制A柜24
4.5.2 电气控制B柜28
4.5.2 电气控制C柜28
5 中段水PLC控制程序部分设计30
5.1 STEP7软件的设计步骤30
5.2 程序总体设计方案30
总结37
致谢38
参考文献39
附录Ⅰ 控制地址表40
附录Ⅱ 子程序介绍54
摘 要
造纸废水按产工艺主要分三部分：蒸煮黑液，中段废水，纸机网下白水。中段废水的处理是重点和难点。制浆中段废水指的是经黑液提取后的蒸煮浆料在洗涤，筛选，漂白以及打浆的过程中所派出的废水。
文章针对制浆中段废水的特点特出了一套结构简单应用效果良好的中段废水好氧处理过程控制方案。废水处理采用好氧生化处理技术，利用好氧微生物在多氧条件下对有机物的很强大的分解功能，采用人工的控制技术从而去除造纸中段废水中的BOD、COD以及SS成分。针对中段水处理工艺要求以及好氧处理控制过程特点，采用基于S7-300PLC的DCS控制系统。结合过程控制原理，可以实现报警、监控以及先进算法自动控制的系统。
该方案采用上位监控计算机和下位机PLC相结合的控制方法。上位监控计算机负责与PLC进行通讯，对整个废水处理流程进行监视和操作，并具有数据记录、故障报警、参数设置等功能。下位机PLC对现场的PH、流量、温度，液位信号及泵阀的运行情况、故障等信号进行采集，并根据预先编制的控制程序输出控制各种泵阀的指示信号，同时完成将下位机的信号传到监控计算机内以接受监控计算机指令。
关键词：PLC，中段水，好氧处理，控制系统
ABSTRACT
Paper production process wastewater in accordance with the main three parts: cooking liquor, the middle of wastewater, under the White Paper Network. The middle of wastewater treatment is a key and difficult. Pulp and refers to the middle of wastewater extracted by the cooking liquor in the pulp washing, screening, bleaching and beating in the process of sending the waste water.
In this paper, pulp and the middle of the characteristics of wastewater outstanding application of a simple structure of the middle effective aerobic treatment of wastewater process control program. Wastewater treatment using aerobic biological and chemical processing technology, the use of aerobic micro-organisms in the anoxic conditions of organic matter decomposition is a powerful feature, the use of artificial control technology in order to remove the paper in the middle of wastewater BOD, COD and SS components. Requirements for mid-water treatment process and characteristics of aerobic treatment process control, based on S7-300PLC's DCS control system. Combined with the principle of process control can be achieved alarm, monitoring, and advanced automatic control system algorithm.
The computer program used to monitor upper and lower PLC integrated control methods. Host is responsible for monitoring the computer to communicate with the PLC of the entire wastewater treatment process monitoring and operation and has a data recording, fault alarm, parameter setting functions. PLC-bit on-site under the PH, flow, temperature, liquid level signal and pump operation, fault, such as signal acquisition, and in accordance with pre-control procedures for the preparation of the various pump output control signal instructions, at the same time to complete the next-bit machine signal reached the monitoring computer monitoring computer to accept commands.
KEYWORDS: PLC, the middle of water, aerobic treatment, the control system
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