PLC苯酐装置氧化工段自控设计+梯形图程序 摘要：苯酐是一种重要的有机化工原料，用于生产增塑剂、醇酸树脂、不饱和聚酯树脂、染料及颜料、医药及农药等。目前，全球苯酐生产所采用的工艺路线有萘流化床氧化和萘/邻二甲苯固定床氧化，其中邻二甲苯固定床氧化技术约占世界总生产能力的90%以上。本设计采用邻二甲苯氧化连续式生产邻苯二甲酸酐，该法工艺比较成熟，资料较多，故采用该工艺。
设计中采用以五氧化二钒为主的钒系催化剂进行邻二甲苯的气相氧化，反应器采用列管式固定床反应器。将过滤后的无尘气经压缩、预热至160℃，与被气化的邻二甲苯蒸气混合后进入反应器，在370℃左右进行催化氧化反应，反应进料空速3200h-1，空气中邻二甲苯浓度40g/m2（标准），反应热由管外循环的熔盐带出。反应产物进入熔盐冷却器，被冷却的反应气经进一步冷却，进入粗酐贮槽，回收粗苯酐。同时介绍了力控组态软件从安装到使用的过程，运用力控苯酐装置氧化工段艺流程图界面设计和控制系统设计。介绍了西门子S7-200PLC，并用其编写梯形图程序实现控制系统的设计，本文来自辣&文*论~文'网，毕业论文 www.751com.cn使用单回路反馈控制系统控制反应器反应温度。通过力控设计的上位机管理界面和西门子S7-200连接实现温度的显示和实时控制。
关键字：苯酐生产；力控；S7-700PLC；反应器
Design of phthalic anhydride oxidation process control
Abstract:Phthalic anhydride is one of important organic Chemical industry material for producing plasticizer、alkyd resin、unsaturated polyester resin、dyestuff and pigment、medicine and pesticide. Currently, the process routes of phthalic anhydride produceing are fluidized bed oxidation of naphthalene and fixed bed oxidation of o-xylene/naphthalene all over the world. And the technology of fixed bed oxidation of o-xylene is about 90% of the world's total production capacity. This design uses the method of o-xylene oxidation to produce Phthalic anhydride continuously. The technology is mature and more information,so it is used.
Phthalic anhydride plant is designed. The design is gas phase oxidation of o-xylene by vanadium catalyst, which is mainly about vanadium pentoxide. The reactor used is tubular fixed-bed reactor. Detailed design process: After fliteration, no the dust gas is compressed、preheated by 160℃, and sent into the reactor mixing with o-xylene steam which has been gasified. Catalyze oxide reaction is continued in 400-460℃. Airspeed of response feed is 3200h-1, the concentration of o-xylene in air is 40g/m2 (stp), heat of reaction is taken away by molten salt, which recycle outside the pipe. Product of reaction sent into salt cooler, cooled reaction gas sent into crude anhydride tank after further cooling. At the same time, Force control configuration software is introduced from installation to use, the process of using the force control for delayed phthalic anhydride oxidation process control design and control. The Siemens S7-200 PLC is introduced, and the ladder diagram programming realize the design of the control system of heating furnace, using furnace temperature and outlet temperature of the heating furnace as the variables of the cascade control system. Through the force control design of PC management interface and Siemens S7-200 connected to realize the real-time display and control of temperature.
Key Words：Phthalic anhydride;The force control; Siemens S7-200;reactor
目录
1绪论 1
1.1 课题的目的和意义 1
1.2 国内外苯酐生产的现状与水平 1
1.2.1 国外苯酐生产现状与水平 1
1.2.2 国内苯酐生产现状与水平 2
1.3 苯酐生产的发展趋势 2
1.4 苯酐生产技术介绍 3
2 软件介绍 5
2.1力控组态软件介绍 5
2.2 力控软件的安装 5
2.3力控产品的特点 9
2.4 PLC的选型和I/O分配 10
2.4.1 西门子S7-200PLC选择 10
2.4.2 西门子S7-200PLC编程软件STEP7-Micro/WIN安装运行 11
2.4.3 PLC的I/O分配 13
3 控制方案的设计实施 13
3.1主要控制方案 13
3.1.1邻二甲苯进料控制 13
3.1.2反应器温度的控制 14
3.2硬件的配置 14
3.2.1 PLC型号的选择 14
3.2.2 S7-200 CPU的选择 15
3.2.3EM235 模拟量输入/输出模块 15
3.3控制设备选型及原理 15
3.3.1流量变送器的选择 15
3.3.2温度变送器的选择 16
3.4梯形图程序 17
3.4.1 PID参数初始化子程序 17
3.4.2 PID中断运算子程序 18
3.4.3 流量数据采集转换子程序 18
3.4.4 氧化控制的主程序 19
3.5 软件设计 21
3.5.1 工程管理 21
3.5.2 工程组态画面 21
3.5.3 配置 I/O设备驱动 25
3.5.4 定义数据库点及数据连接 25
3.5.5 温度趋势曲线图 28
4.结论及总结 29
致谢 30
参考文献 31,2944