Dynamic Modeling And Abnormal Simulation Of Rectifying Tower

As the basis of all the production work, safety is an eternal theme. Chemical industry has an important effect on national economy and people's living life. Because the chemical production takes such characteristics as flammable explosive, virulent harmful, and strongly corrosive, more risks than the other industry may take place, with more serious consequences when accident occurred. Rectifying tower has one pivotal function in the chemical production, where abnormal events occur from time to time. In view of mechanism principles, dynamic model of rectifying tower was built in this work, and abnormal simulation for some typical faults was done.Based on distillation principle, basic condition and operation essence, we investigated flash model at a constant volume and gave a dynamic rectifying tower model. Flash vaporization for mixture with a fixed composition under a fixed volume was done at first, then liquid composition, liquid holdup volume and gas pressure were achieved, and lastly dynamic flash vaporization model for single tank and multiple tanks were established consequently. After that, by iterative calculation of constant volume based flash model, one generalized dynamic rectifying tower model was built, in which the flow rate equations of gas and liquid phase were modified correspondingly. During the model setup procedure, MATLAB software was used to code the model, and dynamic simulation was carried out with it. The final steady-state result obtained was compared with the one coming from PRO/II, one famous process simulation business software, to verify the correctness and accuracy of the model.The fault reason of rectifying tower consists of engineering factor and non-engineering factor. In the above model, we choose three kinds of fault, that is, change of reflux ratio, feed thermal condition, and bottom heating quantity. They all belong to engineering factor and are easy to calculate, control and predict. Having the corresponding fault parameters set in the model, dynamic simulation is utilized to demonstrate consequences which these faults cause, thus it is possible to research fault occurrence behavior, and facilitate early detection and control of abnormal event.This work is the first part of rectifying tower fault diagnosis project based on dynamic simulation, aiming at theory support for distillation diagnosis system building. To establish one hybrid fault diagnosis system, the focus of our future work will be put on the specific fault parameter catch algorithm from measured variables using this model.