Design And Implementation Of PLC Control System For Continuous Nitrification

In organic synthesis,continuous nitrification is a very important type of reaction.Nitrification has strict requirements on temperature,so it is necessary to prevent side reactions such as polynitro and oxidation caused by excessive temperature.Nitrification is an exothermic reaction,with a fast rate and a risk of explosion if the process is not controlled,so it is extremely dangerous.Common nitrating agents are mainly nitric acid of various concentrations,mixed acid(the mixture of nitric acid and sulfuric acid),nitric acid and acetic anhydride of the mixture,etc.,are dangerous chemical raw materials.In order to improve the production quality and strengthen the control of the production process,an automatic monitoring system is designed in this paper,which is based on the continuous nitrification production line of a chemical plant.This paper design of the monitoring system,its lower machine adopts Siemens s7-300 PLC.Through the programming and configuration of Siemens programming software STEP7,automatic control of pressure,temperature and liquid level of the device in the process flow including acid and alkali mixing,nitrification reaction,water washing and extraction can be realized.Kingview is the host computer state software.In order to ensure its safe and efficient operation,remote control,interlock protection,data collection,monitoring data and record management are added.In terms of communication,this subject USES Ethernet to realize the communication between the lower computer PLC and the upper computer's state software.The hardware system,software system and communication system of the subject were debugged,and the results showed that the system could run stably,perform well in the aspects of control function and measurement and control accuracy,and the performance was excellent,which reached the expected value of the design and could complete automatic monitoring.