Experimental research on the factors affecting rectification explosion in nitrobenzene production

The present paper is aimed to introduce the results of study on the thermo-decomposing temperature and self-reaction of the main hazardous substances found in the rectification process,which including nitrobenzene,dinitrobenzene,sodium 2,4-dinitrophenolate and the mixture solutions of nitrobenzene with sodium 2,4-dinitrophenolate. As is known,the hazardous thermal reactive explosion of nitrobenzene tar in the process of industrial production has often aroused great concern of the public.The study on how to solve the problem has become a hot topic in recent years.In this paper,the rapid screening device (RSD) calorimeter purchased from Britain is employed to identify the most hazardous chemical of the nitrobenzene rectification tower through screening technology.Then the kinetic parameters of the hazardous chemicals are acquired from the experimental data,thus the onset temperature of thermal decomposition reaction which is a critical parameter can be found.Meanwhile,the temperature for runaway reaction can also be attained.Based upon the calorimetric data of self-decomposing thermal reaction,mixed solutions of sodium 2,4-dinitrophenolate and nitrobenzene with different concentration ratio (the sodium 2,4-dinitrophenolate/nitrobenzene are 2 × 10~(-5),3× 10~(-5),5 × 10~(-5),and 2× 10~(-4)) are tested by RSD calorimeter. The results of research indicate that,when the hazardous chemicals are heated by programmed increasing temperature,self-decomposing reaction will take place and the decomposition of sodium dinitrophenolate is an exothermic process.Nitrobenzene and dinitrobenzene are stable in the testing condition from ambient temperature to 400 ℃.When sodium 2,4-dinitrophenolate is mixed with nitrobenzene, the reaction is an intensive exothermic process,having a great exothermic runaway risk.RSD calorimeter can be used for basic experimental data determination for the study on the accidents of hazardous devices explosion dealing with exothermic runaway reaction, and providing technical support for safety measures in production,reliability analysis and rating.