The microcosmic reaction mechanism of the thermal decomposition of potassium nitroformate（KNF） has been investigated by density functional theory within the generalized gradient approximation. The geometric structur...The microcosmic reaction mechanism of the thermal decomposition of potassium nitroformate（KNF） has been investigated by density functional theory within the generalized gradient approximation. The geometric structures of reactants, intermediates, transition states, and products are fully optimized. The frequency analysis approves the authenticity of intermediates and transition states. Our results show that there are four feasible reaction pathways. The main pathway of the reaction is KNF → B1 → TSB1 → B2 → TSB2 → B3 → TSB3 → B4 → KNO2 ＋ NO2 ＋ NO ＋ CO, and the energy barrier of the rate-limiting step is 216.30 k J·mol^-1. The dominant products predicted theoretically are KNO2, NO2, NO, and CO, which is in agreement with the experiment.展开更多
The thermal behavior, nonisothermal decomposition reaction kinetics and specific heat capacity of nitrate glycerol ether cellulose（NGEC） were determined by thermogravimetric analysis（TGA）, differential scanning ca...The thermal behavior, nonisothermal decomposition reaction kinetics and specific heat capacity of nitrate glycerol ether cellulose（NGEC） were determined by thermogravimetric analysis（TGA）, differential scanning calori- metry（DSC） and microcalorimetry. The apparent activity energy（Ea）, reaction mechanism function, quadratic equa- tion of specific heat capacity（Cp） with temperature were obtained. The kinetic parameters of the decomposition reac- tion are Ea=170.2 kJ/mol and lg（A/s^-l）=16.3. The kinetic equation isf（α）=（4/3）（1-α）[-ln（1-α）]^1/4. The specific heat capacity equation is Cp=1.285-6.276×10^-3T＋1.581×10^-5T^2（283 K〈T〈353 K）. With these parameters, the thermal safety properties of NGEC were studied, such as the self-accelerating decomposition temperature（TSADT）, critical temperature of thermal explosion（Tb） and adiabatic time-to-explosion（tTlad）. The results of the thermal safety evalua- tion of NGEC are： TSADV=459.6 K, Tb=492.8 K, tTlad=0.8 S.展开更多
This study developed a numerical model to efficiently treat solid waste magnesium nitrate hydrate through multi-step chemical reactions.The model simulates two-phase flow,heat,and mass transfer processes in a pyrolysi...This study developed a numerical model to efficiently treat solid waste magnesium nitrate hydrate through multi-step chemical reactions.The model simulates two-phase flow,heat,and mass transfer processes in a pyrolysis furnace to improve the decomposition rate of magnesium nitrate.The performance of multi-nozzle and single-nozzle injection methods was evaluated,and the effects of primary and secondary nozzle flow ratios,velocity ratios,and secondary nozzle inclination angles on the decomposition rate were investigated.Results indicate that multi-nozzle injection has a higher conversion efficiency and decomposition rate than single-nozzle injection,with a 10.3%higher conversion rate under the design parameters.The decomposition rate is primarily dependent on the average residence time of particles,which can be increased by decreasing flow rate and velocity ratios and increasing the inclination angle of secondary nozzles.The optimal parameters are injection flow ratio of 40%,injection velocity ratio of 0.6,and secondary nozzle inclination of 30°,corresponding to a maximum decomposition rate of 99.33%.展开更多
基金supported by the Scientific and Technological Research Program of Chongqing Municipal Education Commission(KJ131318,KJ1401227,KJ15012002)the Fuling Science and Technology Commission(FLKJ2015ABA1042)the Project of Chongqing Key Laboratory of Inorganic Special Functional Materials(KFKT201506)
文摘The microcosmic reaction mechanism of the thermal decomposition of potassium nitroformate（KNF） has been investigated by density functional theory within the generalized gradient approximation. The geometric structures of reactants, intermediates, transition states, and products are fully optimized. The frequency analysis approves the authenticity of intermediates and transition states. Our results show that there are four feasible reaction pathways. The main pathway of the reaction is KNF → B1 → TSB1 → B2 → TSB2 → B3 → TSB3 → B4 → KNO2 ＋ NO2 ＋ NO ＋ CO, and the energy barrier of the rate-limiting step is 216.30 k J·mol^-1. The dominant products predicted theoretically are KNO2, NO2, NO, and CO, which is in agreement with the experiment.
基金Supported by the Foundation of National Key Laboratory of Science and Technology on Combustion and Explosion of China(No.9140C3503011004)
文摘The thermal behavior, nonisothermal decomposition reaction kinetics and specific heat capacity of nitrate glycerol ether cellulose（NGEC） were determined by thermogravimetric analysis（TGA）, differential scanning calori- metry（DSC） and microcalorimetry. The apparent activity energy（Ea）, reaction mechanism function, quadratic equa- tion of specific heat capacity（Cp） with temperature were obtained. The kinetic parameters of the decomposition reac- tion are Ea=170.2 kJ/mol and lg（A/s^-l）=16.3. The kinetic equation isf（α）=（4/3）（1-α）[-ln（1-α）]^1/4. The specific heat capacity equation is Cp=1.285-6.276×10^-3T＋1.581×10^-5T^2（283 K〈T〈353 K）. With these parameters, the thermal safety properties of NGEC were studied, such as the self-accelerating decomposition temperature（TSADT）, critical temperature of thermal explosion（Tb） and adiabatic time-to-explosion（tTlad）. The results of the thermal safety evalua- tion of NGEC are： TSADV=459.6 K, Tb=492.8 K, tTlad=0.8 S.
基金the financial support for this work provided by the National Key R&D Program of China‘Technologies and Integrated Application of Magnesite Waste Utilization for High-Valued Chemicals and Materials’(2020YFC1909303)。
文摘This study developed a numerical model to efficiently treat solid waste magnesium nitrate hydrate through multi-step chemical reactions.The model simulates two-phase flow,heat,and mass transfer processes in a pyrolysis furnace to improve the decomposition rate of magnesium nitrate.The performance of multi-nozzle and single-nozzle injection methods was evaluated,and the effects of primary and secondary nozzle flow ratios,velocity ratios,and secondary nozzle inclination angles on the decomposition rate were investigated.Results indicate that multi-nozzle injection has a higher conversion efficiency and decomposition rate than single-nozzle injection,with a 10.3%higher conversion rate under the design parameters.The decomposition rate is primarily dependent on the average residence time of particles,which can be increased by decreasing flow rate and velocity ratios and increasing the inclination angle of secondary nozzles.The optimal parameters are injection flow ratio of 40%,injection velocity ratio of 0.6,and secondary nozzle inclination of 30°,corresponding to a maximum decomposition rate of 99.33%.
