论文总字数：26847字

摘 要

生物甲烷是一种优质的可再生绿色能源，能够代替化石燃料以缓解全球能源危机问题。但是天然沼气中除了含有甲烷，还含有少量的CO₂、H₂O、N₂、H₂S等杂质气体，使其热值较低、利用受限。随着最近几年经济技术的发展，多种甲烷提纯技术被开发并得到不断发展。其中高压水洗方法是针对沼气中的存在的大量CO₂和H₂S等杂质气体进行脱除的技术，它是目前使用较为普遍的的沼气脱碳方法，本文根据其工艺流程及控制要求开发了一种基于西门子S7-200 Smart PLC和WINCC的自动控制系统。该系统能够实现沼气从进气到水洗再到气液分离等全过程的自动控制和实时监控。本文主要内容如下：

1.首先我们介绍了PLC的概念、结构和工作原理，再根据实际的工艺流程来确定控制系统所需的PLC的型号；其次根据自动控制的设计标准分别对温度仪表、压力仪表、液位仪表和流量控制器进行选型；然后根据系统要求和物料特性对阀门进行选型确定气动特性和流量特性；最后对系统中的部分电气接线进行和控制柜进行设计。

2.分析工艺流程和吸收塔等反应器的特性，确定在高压水洗控制系统中控制目标，对可能出现的扰动因素进行详细分析并设计出吸收塔和闪蒸罐等设备的控制方案，在方案设计中主要涉及对吸收塔和闪蒸罐的的进气流量、进水流量、压力 、液位等参数的控制，在必要的情况下要设计PID回路进行控制设计。

3.我们在高压水洗系统中，我们是通过WINCC组态软件来对系统中各个参数进行模拟，系统中的主要参数有进料流量、塔压、水位等，我们可以通过WINCC组态软件对整个系统进行动态模拟并实时监控整个运行系统的运行，而且能够实现PID参数的在线调整、数据的历史记录和报警记录等功能。

本论文设计的沼气高压水洗自动控制装置，经现场测试，运行稳定，运行结果表明，该系统运行稳定，具有良好应用前景。

关键词：高压水洗；生物质新能源；自动控制；PLC；WINCC

Abstract

Bio methane is a kind of high quality renewable green energy, which can replace fossil fuels in order to alleviate the problem of global energy crisis. However, in addition to containing methane gas, but also contains a small amount of CO2, H2O, H2S, N2 and other impurities of gas, so that the lower calorific value, the use of limited. Along with the development of economy and technology in recent years, many kinds of methane purification technology has been developed and developed continuously. The high-pressure water washing method is for methane in the presence of large amounts of CO2 and H2S gas impurity removal technology. It is currently used universally methane decarbonization method, this paper based on the technological process and control requirements developed a kind of automatic control system based on Siemens S7-200 smart PLC and WinCC.The system can realize the automatic control and real-time monitoring of the whole process of methane from the air inlet to the water washing and gas - liquid separation. The main contents of this paper are as follows:

1. Firstly, we introduce the concept, structure and working principle of PLC, according to the actual process to determine the PLC control system for model; secondly according to the design standard of automatic control respectively to temperature gauges, pressure gauges, liquid level gauges and flow controller are selected; then according to the system requirements and material characteristics of valve selection to determine the aerodynamic characteristic and the flow characteristic. Finally on the part of the electrical wiring and the control cabinet is designed.

2. The analysis process and absorption tower reactor characteristics were determined in the high-pressure water washing control system control objectives, of possible disturbance factors of detailed analysis and design of absorption tower and a flash tank and other equipment control scheme. In the scheme design mainly involves the absorption tower, and a flash tank of air flow and water flow, pressure, level and other parameters of control and in the necessary to design the PID loop control design.

3. We in the high pressure water washing system, we are through WinCC configuration software to simulate the various parameters of the system and the main parameters of the system with the feed flow rate, column pressure, water level, we can run through the WinCC configuration software of the whole system of dynamic simulation and real-time monitoring of the operation system, but also can realize the online adjustment of PID parameters, historical data and alarm record.

In this paper, the design of the automatic control device for high pressure water washing, the field test, stable operation, operation results show that the system is stable and has good application prospects.

Key Word：high pressure washing；new biomass energy；automatic control；PLC；WINCC

目 录

摘要 I

Abstract II

目录 III

第一章 绪论 1

1.1 课题的背景及意义 1

1.2 国内外研究现状 2

1.3 常用提纯工艺与装置设计 4

1.3.1 沼气提纯工艺 4

1.3.2 本课题提纯装置设计 5

1.3.3 本文研究内容 5

1.4 本文小结 6

第二章 高压水洗系统硬件部分设计 7

2.1 高压水洗系统工艺介绍 7

2.2 PLC选型介绍 8

2.2.1 PLC概念和结构 8

2.2.2 PLC的工作原理 10

2.2.3 PLC及其扩展模块选型 10

2.3 其他元器件选型 11

2.3.1 进水流量调节阀 11

2.3.2 出气调节阀 12

2.3.3 电动调节阀 13

2.3.4 进水流量计 13

2.3.5 温度测量仪表 14

2.3.6 压力变送器 15

2.4 部分电气接线方式介绍 15

2.4.1 系统供电接线 15

2.4.2 继电器模块接线 16

2.4.3 PLC接线端子图 17

2.4.4 控制柜设计 17

2.5 设备选型清单 18

2.6 本章小结 20

第三章 高压水洗控制系统软件程序设计 21

3.1自动控制方案的设计 21

3.2 PLC程序设计的基本步骤 23

3.3 S7-200 SMART PLC的程序设计方法 25

3.4.1 初始化程序 26

3.4.2 数据采集程序 27

3.4.3 主程序设计 27

3.4.4 PID调节 28

3.5本章小结 28

第四章 组态界面的设计 29

4.1 组态软件与通信协议 29

4.1.1 组态软件选择 29

4.1.2 WINCC与S7-200 PLC Smart的通信协议 29

4.1.3 PC Access Smart软件 30

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