用加速量热仪研究乳化炸药的热稳定性

STUDY OF THERMAL STABILITY OF EMULSION USING ACCELERATING RATE CALORIMETER

使用加速量热仪 (ARC)研究了一种新型乳化炸药的热稳定性。得到了乳化炸药样品的热分解温度和压力随时间的变化曲线以及自热速率、分解压力随温度的变化曲线 ,分析了其热分解过程 ,计算了表观活化能 Ea 和指前因子 A。测试和分析结果表明所测试的乳化炸药具有良好的热稳定性。

The thermal stability of a new emulsion for two sample systems is investigated using an adiabatic calorimeter called ARC (Accelerating Rate Calorimeter). The main components of the two sample systems are the same as NH 4NO 3 / H 2O / combustible agent /90 / 3 / 7 except for the sample No. 2 in which 0.1% talcum powder is added for the purpose of comparison. The combustible agent includes emulsion agent, urea, fossil wax, paraffin and trace additives. Sample No. 1 weighted 0.586 9 g and sample No. 2 0.562 0 g are loaded in titanium bombs weighted 6.38 g and with volume of 9 cm 3. The starting temperature and the sensitivity are set at 90 ℃ and 0.02 ℃/min. After the sample reaction system including the sample and bomb reaches the temperature of 90 ℃, the procedure of 5 ℃ steps of heating-10 minutes waiting-searching is carried out automatically by the processor controller until a self heating rate greater than 0.02 ℃/min is detected. The reaction system is then heated by reaction heat under adiabatic conditions. The curves of thermal decomposition temperature and pressure versus time, and the self heating rate and pressure versus temperature are obtained (Figs. 2 and 3) The basic data including the initial exothermic temperature (204.80 ℃ and 214.93 ℃ for No. 1 and No. 2 samples respectively), the maximum temperature (402.98 ℃ and 371.47 ℃) , the maximum pressure (5.67 MPa and 6.44 MPa), the activation energy (168.79 kJ·mol -1 and 162.56 kJ·mol -1 ) and the pre exponential factor (1.13×10 15 s -1 and 9.73×10 14 s -1 ) of the thermal decomposition are given (Tables 1 and 2) to evaluate the thermal stability of the new emulsion explosive. The measured results (Table 1) indicate that the new emulsion explosive is of good thermal stability and the physical endothermic process exists during the slow initial thermal decomposition with very low self heating rate. When the sample temperature and pressure rise up to a certain value (263.92 ℃/1.16 MPa and 229.87 ℃/2.29 MPa for No. 1 and No.2 samples respectively), the temperature and the pressure ramp up to a high level (265.63 ℃/1.47 MPa and 297.20 ℃/3.71 MPa respectively) and there is no obvious transient between the slow process and the ramp.