Thermal Risk Assessment On DINA Synthesis Process

DINA is a widely used energetic material,which is mainly produced by magnesium nitrate process in China.The research on the production process mainly focused on the economy of the synthesis process and the safety of products.The risk of thermal runaway in the synthesis process was hardly involved.In order to further identify and reduce this risk,it is necessary to conduct in-depth and systematic research on the thermal hazard of its synthesis process.DINA was synthesized by two different routes on a small scale.The functional groups of the reaction system were studied by Fourier transform infrared spectroscopy?FTIR?,and the thermal stability of the products at different stages was tested by differential scanning calorimeter?DSC?.It was found that the initial decomposition temperature of the reaction system was lower and the thermal stability was worse in both synthetic routes.It was found that the most unstable reaction stage in the synthesis of Gina was the esterification product system of fuming nitric acid and diethanolamine.The initial decomposition temperature was the lowest at about 70?,and the specific heat was 1500J/g.The reaction exothermic characteristics of the synthesis process were studied by calorimetric experiments.The MTSR of each step of the process was calculated to be 35?,55?and 102?,and the adiabatic temperature rise of the target reaction was 148.0?,127.0?and 36.5?,respectively.The specific heat of decomposition was 1468.5 J/g,1394.9 J/g and 1634.3 J/g in the adiabatic form of products at each stage by ARC experiment.The T_D24 of samples at each stage was calculated from ARC data to be 15.6?,18.6?and91.6?respectively.The risk matrix method was used to evaluate the risk of thermal runaway of target reaction,and the result shows that the thermal runaway risk of target reaction is“unacceptable”.Through the analysis of runaway situation to evaluate the target process,the conclusion is that the risk of thermal runaway in each stage of target reaction is“5”,which is unacceptable.The thermal stability of washing products and alkali washing products in the treatment process was studied.There is an unstable by-product in the washing product.According to DSC experiment with linear heating,the Ea-?curve of the by-product is obtained by Fridemen method.According to the experimental results of isothermal DSC,the Autocatalytic Decomposition Characteristics of the by-product were observed.The apparent kinetics of the decomposition was obtained by using the Autocatalytic Decomposition Model of TSS,and the reaction rate equation was as follows:According to this kinetics,T_D24 and T_D8 of this substance were obtained at 27.3?and 40.2?,respectively.At the same time,the Ea-?curve of alkali washing products was obtained by Fridemen method.According to the kinetic results,the T_D24 and T_D8 of alkali washing products were 97.3?and 109.6?respectively.In this paper,the risk of thermal runaway in the preparation of DINA process is studied,and the relevant thermal safety parameters are obtained.It has guiding significance for the setting of process temperature and alarm temperature in the production process and post-processing of DINA.