Kinetic parameter estimation for decomposition of organic peroxides by means of DSC measurements

The thermal stability of organic peroxides (cumene hydroperoxide 80 wt% and dicumyl peroxide) was studied by means of calorimetric measurement (DSC, TA Q1000) in an isotherm mode and a dynamic mode. Analysis of power profiles released in the isothermal mode was combined with the analysis of the decomposed compounds by a gas chromatograph/mass spectrometer (GC/MS) to determine the reaction mechanisms corresponding to each of the two reactions. In this work, a methodology for estimating kinetic parameters was based on the comparison of the power profile (dynamic mode) given by the model to that obtained experimentally by changing the parameters values. Parameter estimation is achieved using the mixed estimation method where a genetic algorithm is combined with a locally convergent method.     

Explosive properties of selected aerosols determined in a spherical 5-L test chamber

Combustible liquids in the form of aerosols are important for many industrial processes. Therefore the problem of explosion hazards posed by the aerosols becomes increasingly more prominent. To correctly assess the explosion risk and fulfil the requirements of the ATEX directive, it is necessary to obtain information regarding the flammable and explosive properties of the aerosols. Unlike in the case of gases and dusts, no standard procedures aimed at obtaining quantitative information of this type exist. Factors that influence the explosion dynamics of aerosols include: concentration, droplet size, temperature etc. Some of these factors are strongly dependent on the aerosol generation methods. A prototype apparatus was designed and constructed to address that dependence. The apparatus was used in an attempt to determine the basic explosion parameters of liquid flammable aerosols. The device consisted of a 5-L spherical vessel equipped with a pump-injection system that generated aerosols as well as a spark ignition source. A wide variety of injection settings were tested to select the most suitable conditions over a broad range of concentrations and fluid properties. A measurement procedure was developed for operating the device. Prototype tests were carried out with fluids commonly used in industry: isopropanol and kerosene. The tests demonstrated the significant influence of the vessel wall temperature on the result accuracy. Correct temperature control made it possible to obtain relationships between the aerosol concentration and the following explosion parameters: maximum explosion pressure and maximum rate of pressure rise.     

炸药及火工品可靠性与安全性评定方法

可靠性的评定结果是否可信,直接关系到炸药及火工品的使用安全性和作用可靠性。但是,现有炸药及火工品可靠性评定方法却存在着达不到置信度要求、评价结果偏于危险的缺点。为此,提出了一种确定炸药及火工品安全度和可靠度的高精度方法,并给出了应用实例。该方法不仅可信程度高,而且适用于小样本情况,尤其是在利用了以往试验数据后,既可提高安全性和可靠性评定的精度,又可大大节省试验的费用及时间     

Calorimetric behaviors of N2H4 by DSC and superCRC

The objective of this study is to obtain information about the thermal decomposition behaviors of hydrazine (N₂H₄) caused by metals, using differential scanning calorimeter (DSC) and SuperCRC. The DSC measurements revealed that the exothermic reactions of N₂H₄ were caused by the reaction conditions such as the type of cells; the T_DSC with a gold pan is 485.2 K and that with a glass capillary is 620.5 K. Besides, the activation energy of the thermal decomposition of N₂H₄, calculated from the Kissinger and Ozawa methods, were found to be about 38±2 kJ mol⁻¹ in the gold pan and 141±8 kJ mol⁻¹ in the glass capillary. Moreover, a heat flow profile was observed with SuperCRC during the mixing of N₂H₄ and the metal ion solution at 298 K. The maximum heat flow was related to the metal ion oxidative characters. The higher oxidative characters would provide a faster acceleration for the exothermic behavior than the lower oxidative ions. Based on this study, Mn(VII) and Cr(VI) were considered to exhibit strongly oxidative characteristics during mixing with N₂H₄.     

镁粉爆炸特性和惰化抑爆的实验研究

采用20 L球形爆炸测试装置,考察了镁尘浓度、镁粉粒度、点火能量对镁粉爆炸过程热力学参数Pmax、动力学参数(dP/dt)max的影响;选取CaC03粉末作为惰化剂,考察惰化剂含量、情化剂粒度对镁粉爆炸抑制性能的影响,提出了预防镁粉爆炸、降低爆炸危害的本质化安全对策.结果表明,镁尘浓度、点火能量越高,爆炸危害越大;镁粉...     

城镇燃气爆炸极限影响因素与计算误差的分析

可燃气体的爆炸极限是消防报警和安全使用燃气的重要参数之一 ,笔者对影响城市燃气爆炸极限的因素进行了讨论 ;同时指出有关文献上公布的燃气爆炸极限是一定条件下测定的 ,当空气中含有略低于文献公布爆炸下限或略高于文献公布爆炸上限的可燃气体 ,在一定的条件下也可能产生爆炸。对燃气爆炸极限的计算方法及其计算误差进行了分析 ,指出在使用测试或计算爆炸极限时应考虑安全系数     

易燃易爆气体泄漏的危险性分析

从现代社会中广泛使用和运输的易燃易爆气体着手,介绍了气体泄漏后的几种重要参数的模型,同时总结了这些气体的毒害机理、易发生火灾和爆炸的特点,同时指出了火灾和爆炸的模型,使人们可以深刻地认识其毒害性.     

输油管道中汽油蒸汽爆炸的规律研究

综合考虑湍流及化学反应动力学机理对燃烧的影响,建立了详细流动耦合简化的详细化学反应机理的湍流燃烧模型,以有限体积法求解爆炸流动及反应控制方程,对二维压力管道中汽油蒸汽爆炸的过程及规律进行了数值模拟,模拟结果与实验数据有较好的吻合性;分析了各种组分的变化过程及对爆炸的控制作用.为汽油蒸汽爆炸特性及规律的进一步研究、工业防...     

易燃易爆重大危险源事故概率计算

分有人介入和无人介入重大危险源监测系统两种情况，运用马尔可夫过程研究了重大危险源发生事故的概率，并进行了实例计算。所给概率模型可用于重大危险源的安全评价。【关键词】##4易燃易爆重大危险源;;马尔可夫过程;;安全评价;;事故概率计算;;安全监测系统     

易燃、易爆、有毒重大危险源评价方法与控制措施

论述了重大危险源和重大事故隐患的定义;介绍了易燃、易爆、有毒重大危险源评价方法;在辨识评价的基础上,提出了制定重大危险源事故应急计划,加强监控、管理等措施     

乳化炸药生产线危险源安全措施探讨

本文从乳化炸药的原材料、工艺、设备等方面,分析探讨了乳化炸药生产线危险源所在及其危险性,并提出了相应安全技术措施,这对安全生产具有一定指导意义。     

Comparisons of TGA and DSC approaches to evaluate nitrocellulose thermal degradation energy and stabilizer efficiencies

This study investigated the thermal degradation energy (activation energy, E_a) for nitrocellulose (NC) with low nitrogen content of 11.71 mass%, so-called NC3, by using two different kinds of thermal analysis instruments: thermogravimetric analyzer (TGA) and differential scanning calorimetry (DSC). A comparison of E_a for various nitrogen content NC samples at two scanning rates (5 and 10 °C min^?1) tested by TGA and DSC is also discussed in this paper. Meanwhile, our aim was to analyze the anti-degradation of E_a for NC with high nitrogen content, as so-called NC1. Thermal stability for NC1 with diphenylamine (DPA) was tested via DSC with 10 DPA concentrations in weights of 0, 0.25, 0.50, 0.75, 1.0, 1.25, 1.50, 1.75, 2.0, and 3.0 mass%. Experimental results indicated that E_a of NC3s was 319.91 kJ mol^?1. Moreover, that while dosing DPA into NC1 the best recipe could be employed to avoid any violent NC1 runaway and also can be used to distinguish the differences of thermal decomposition E_a between NC with different nitrogen contents. This study established a fast and efficient procedure for thermal decomposition properties of NC, and could be applied as an intrinsically safer design during relevant operations.     

锅炉过热器爆漏原因的统计分析和预防措施

以100余起公开报道的锅炉过热器爆漏事故案例进行统计分析为基础,将引起过热器爆漏的直接原因归纳为长期超温、短期超温、腐蚀、磨损和焊接缺陷,对产生事故的机理和主要原因进行了探讨和归类,认为运行管理不当是造成过热器爆漏的最重要方面。分析并提出了设计、安装、制造、检修和运行管理过程中对爆漏风险贡献最大的各单因素及其成因。针对造成爆漏的根本原因提出了预防措施,为锅炉的安全运行和合理检修提供了科学依据。     

风电机组与民爆危险品建筑物间安全防护距离的研究与选定

针对风电机组选址与民爆企业安全管理的突出矛盾,研究分析了风电机组和民爆危险品建筑物间安全距离设定的原则和方法,深入剖析了重大危险影响因素,并结合现行标准规范和国外相关规定及经验做法,估算了安全距离值,探讨了安全距离设定的可能性、合理性和适应性,提出了安全距离设定的建议和参照依据。     

Thermal hazard analysis of triacetone triperoxide (TATP) by DSC and GC/MS

Thermal degradation of triacetone triperoxide (TATP) was studied using differential scanning calorimetry (DSC) and gas chromatography/mass spectrometry (GC/MS). TATP, a potential explosive material, is powerful organic peroxide (OP) that can be synthesized by available chemicals, such as acetone and hydrogen peroxide in the laboratory or industries. The thermokinetic parameters, such as exothermic onset temperature (T₀) and heat of decomposition (ΔH_d), were determined by DSC tests. The gas products from thermal degradation of TATP were identified using GC/MS technique.In this study, H₂O₂ was mixed with propanone (acetone) and H₂SO₄ catalysis that produced TATP. The T₀ of TATP was determined to be 40 °C and E_a was calculated to be 65 kJ/mol. A thermal decomposition peak of H₂O₂ was analyzed by DSC and two thermal decomposition peaks of H₂O₂/propanone were determined. Therefore, H₂O₂/propanone mixture was applied to mix acid that was discovered a thermal decomposition peak (as TATP) in this study. According to risk assessment and analysis methodologies, risk assessment of TATP for the environmental and human safety issue was evaluated as 2-level of hazard probability rating (P) and 6-level of severity of consequences ratings (S). Therefore, the result of risk assessment is 12-point and was evaluated as “Undesirable” that should be enforced the effect of control method to reduce the risk.     

静电放电对电火工品作用机理分析与试验研究

在分析电火工品静电作用机理的基础上,利用瞬态脉冲试验原理研究了静电放电对电火工品的性能影响。分析了因电火工品个体差异导致分组不均给试验带来的影响,提出用瞬态脉冲试验得到的温升参数对样品进行分组,以保证试验样品的一致性。研究结果表明,经过静电放电试验后,电火工品温升值变大,平均作用时间变长。说明可以用瞬态脉冲试验法检测经静电放电后电火工品的性能变化。     

易燃易爆危险物质泄漏扩散仿真及其应用的研究

以某轻烃厂泄漏事故为研究对象，研制并开发了一个事故后果仿真软件（ＰＣＩＭＳ）．针对仿真过程中存在的问题，如模型的复杂性、参数的不确定性等提出了处理方法．通过具体生产装置的泄漏扩散后果分析，演示了ＰＣＩＭＳ的仿真结果     

压装高聚物粘结炸药湿法筛分的研究

针对高聚物粘结炸药的粒度分级 ,研究了一种以水为介质而具有本质安全性的筛分方法 ;根据界面化学原理采用添加润湿剂和消泡剂的技术使筛分工艺进一步完善。数种配方的应用表明 ,该法不仅具有安全、高效的特点 ,而且有利于提高产品的使用性能和安全性