Study On Measurement Method Of Heat Release Of Reaction System Under Reflux Condition

The reaction heat plays an important role in the safety assessment of chemical processes.Experimental measurements of reaction heat can be used for process design,optimization and thermal risk assessment.The existing reaction heat measurement methods are used under the condition of sample temperature change,but the reaction system has reached the boiling point under reflux condition,and the existing methods can not measure the reaction heat.In order to solve this problem,this paper studies the heat release measurement method of the reaction system under reflux condition from the heat balance theory,structure composition principle,heat release measurement method,model establishment and analysis of the influence factors of heat release measurement,measurement and control module and heat return flow experiment.Firstly,on the basis of the theory of heat flow balance of the system,the measurement method of reaction heat release under reflux condition is designed,and the overall design of the system is carried out.According to the measurement process of reaction heat release,the calorimetric experiment flow under reflux condition was designed,and the control mode suitable for the experiment flow was also designed.The reflux module and basic module of the system are designed according to the calorimetric function requirements under reflux condition.Secondly,the simulation model of return flow heat system is established,and the influencing factors of reaction heat release measurement are analyzed regularly by using the model,which provides guidance for the experiment.Due to the phase transformation of the reaction system under reflux condition,heat and mass transfer exist in both the reaction kettle and condensing tube models.To simplify the model,the system is divided into four modules and the lumped parameter method is used to model the system.And then through the model simulation and actual experiment verifies the feasibility of the model,according to the working condition of reflux reaction heat measurement experiment process,using electric power simulation method on the model of exothermic reaction exotherm measurement experiment,at the same time,combined with the key intermediate of experiment to analyze the influence factors of reaction heat measurement,experiment and the results of the analysis is given for reference.Thirdly,according to the functional requirements of the reflux condition,the measurement and control module of the system is designed,that is,the structure design of the reflux module,the system hardware and software design.The reflux module includes the structure design of adjustable reflux ratio and the selection of key components.The hardware mainly includes temperature measurement,loop ratio control part,followed by power supply,central control and communication storage part.The software part mainly includes reflux ratio control program,master control program,data conversion and acquisition program,data receiving and sending program,system initialization program,etc.Finally,according to the rules of the simulation experiment,the experimental scheme was designed to verify the reaction heat measurement method through the return flow heat experiment.The experimental results show that the relative errors of the reaction heat measurement are within 5%,and the method has accuracy,repeatability and practicability in the reaction heat measurement under reflux conditions.