Research On Observer Based Temperature Control And Fault Detection Method For Polymerization Kettle

The chemical industry is pervasive in human society and is closely related to human life.Many complex equipments are used in the chemical industry,among which reactors are one of the common equipments,mainly used for heating,stirring and reaction processes.The working condition of the reactor is very important for the production quality,and it is the first consideration to ensure the stability of the reactor working condition.Reactor temperature control is the most common and important control process in chemical production.Since the temperature status inside the kettle cannot be obtained directly,it can only be displayed by sensors,and then the feedback control of the kettle is carried out according to the data from the sensors.However,the reactor works mainly in high temperature and high pressure environments,and the internal temperature and air pressure inside the reactor rise sharply in a short period of time due to the irreversible exothermic reaction,so it is important to observe the temperature inside the reactor,which not only affects the product quality and production efficiency,but also can cause the reactor to explode and cause catastrophic accidents.In this article,we focus on the continuous stirred tank reactor(CSTR)system,which is widely used in chemical industry,to design the observer and monitor the sensor fault based on the observer,so as to ensure the timely and accurate acquisition of the kettle status,and then feedback the status to the control system to achieve the purpose of temperature control.The details of the research are as follows:First,a class of segmented linear system with the system temperature state as the critical value is designed based on the analysis of the reactor mechanism model and the production process of polyvinyl chloride in chemical production to reduce the modeling error.Then,we design an observer for this segmented linear system to meet the working conditions and prove its stability,combine the observer to give a suitable fault detection scheme for the system and simulate it numerically using Matlab,and obtain more satisfactory experimental results to verify the feasibility of the proposed method.Furthermore,considering the existence of many uncertain disturbances in practical engineering and modeling,an observer based on unknown inputs is designed for segmented linear systems containing unknown disturbances,and fault detection of system sensor faults is performed,and the feasibility of the used method is demonstrated by numerical simulation.Finally,the work of this article is summarized to point out the shortcomings and to provide an outlook on the subsequent research content.