化学放热系统热爆炸潜在危险性评价

讨论化学放热系统的热稳定性和临界条件,用化学反应物无消耗的假设推导化学放热系统热失控(热爆炸)时的动力学参数临界值,得到热失控的判据、临界点火温度和熄火温度。提出用系统安全指数概念来评价放热反应系统发生热爆炸的潜在危险性,分析化学放热系统的平衡域。用硝酸甲酯分解爆炸实例,说明如何利用安全指数对具有热爆炸可能性的系统的潜在危险性进行定量评价,其预测结果与实验结果一致。     

醇对过氧化氢热危险性的影响研究

为了防止过氧化氢在生产、储存、运输和使用过程中因为混入杂质导致火灾爆炸事故,利用绝热加速量热仪对过氧化氢及其掺杂醇类物质后的放热分解过程进行了试验研究.结果表明,醇使过氧化氢的初始放热分解温度、活化能和SADT均降低,热危险性增加;正丙醇对过氧化氢热分解的促进作用大于无水甲醇和无水乙醇.     

爆炸灾害的预防和控制乃当务之急

我国爆炸事故近年来屡屡发生，灾害严重，损失巨大。爆炸灾害的预防与控制己是当务之急。当前的主要研究内容，有各种工业粉尘爆炸、气液贮罐爆炸、工业生产中的静电灾害、各种爆炸灾害的实验观测和监控技术、防护与控制技术、模拟与仿真技术、易燃易爆物的危险性评估和系统安全性分析、燃烧转爆炸机理和热爆炸（热自燃）机理等方面。简略介绍了爆炸灾害预防、控制国家重点实验室的筹建工作，希望得到同行专家的指导和帮助，并开展合作研究。     

基于小尺寸试验的过氧化氢储运过程热风险评估

近年来过氧化氢储运过程中的爆炸事故频发,因此对其进行热风险评估意义重大.利用自制小尺寸试验装置模拟200 mL质量分数30％ H2O2溶液在10 mL0.1 mol/L Fe2(SO4)3杂质催化作用下的热分解反应,并全程记录反应历程中的温度和压力等参数.基于热失控模型,采用绝热温升△Tad和到达最大温升速率时间TMRad分别作为事故严重度和事故可能性评估指标.结合小尺寸试验所测数据对过氧化氢储罐进行风险评估.结果表明,TMRad随初始温度T0增大而减小,其值均小于试验值,且其二者差值随T0增大而增大.此外,在T0为18℃时,过氧化氢分解未发生失控反应,这表明当T0低于一定值时,将不会发生失控反应.绝热平衡法从最坏情景进行评估,其值相对实测值较保守,但从安全的角度是可行的.如初始温度为39.9℃时,评估值TMRad为108 s,略小于非绝热条件下到达最大温升速率时间的试验值118 s.这表明该法可用于过氧化氢储罐的热风险评估,但该评估方法的精确性有待提高.     

基于FTA和ISM的氯化反应失控火灾爆炸危险性分析

为加强甲烷热氯化工艺过程的安全管理,对氯化反应过程进行危险性分析。本研究介绍了氯甲烷的危害特性以及反应釜失控造成火灾爆炸的危险性,借助事故树分析法中结构重要度的排序获取基本原因事件,在此基础上运用解释结构模型(ISM)对氯化反应过程进行火灾爆炸危险性分析,根据所得基本原因事件的层级划分可得到造成事故发生的直接、间接以及根本原因,最终由ISM分析结果提出针对甲烷热氯化工艺火灾爆炸事故的安全对策措施。     

硝基苯精馏再沸器爆炸事故机理研究

笔者借助实验方法,对硝基苯精馏再沸器爆炸事故机理进行探讨。研究了再沸器中焦化物和焦油这两种主要介质的热爆炸敏感性,认为焦化物的热爆炸敏感性远远超过焦油;通过研究工艺过程,得出爆炸性焦化物是由液面的频繁波动、加热控制错误及可爆物含量升高等原因引起的,过程中可能存在的爆炸触发能量种类主要为氧化热、分解热或者摩擦、撞击能;进一步分析得出了再沸器爆炸事故的机理及爆炸事故的发展过程,认为在触发能作用下,首先是干燥的裸露焦化物被引爆,其产生的爆炸冲击能量可能进一步触发部分焦油,导致二次爆炸;最后根据分析得出的爆炸物形成原因及引爆能出现的条件提出了相应的安全对策措施。     

低压环境对锂电池热失控释放温度影响

为研究锂电池在民航飞行低压特殊环境的安全性及发生热失控灾害后的高温危险性,通过可模拟飞行变动条件的动压变温实验舱开展系列实验,研究锂电池在不同低压环境下的（101,60,30 kPa）多节18650型锂离子电池热失控温度特性,采集电池池体温度及热失控喷射释放温度等参数。研究结果表明:随环境压力降低,圆柱锂电池间的热失控传播并不能被阻断,但锂电池热失控灾害所释放产生的高温区域减少,且高温持续时间变短,释放所产生温度的高温危险性随环境压力的降低而有所降低。     

乙酸酐水解反应热风险分析研究

近年来我国发生的数起重大火灾、爆炸等事故中大部分是由化学物质引起,主要是由于在生产过程或是运输、储存过程中热量过多积聚。针对热失控问题进行风险分析研究,首先简要概述了化工工艺的热安全研究进展,然后从搅拌速率、滴加速率、温度等角度对乙酸酐水解反应的放热特性进行实验分析研究,并进行了热危险性评估。结果表明温度对反应过程产生较大影响,最佳水解温度是50℃,乙酸酐的表观活化能是56.08 kJ/mol,反应过程热危险性低,正常操作条件下不造成热失控。     

锂离子电池热失控危险性研究进展

锂离子电池广泛应用的同时也出现了燃烧、爆炸等安全问题.针对锂电池热失控及火灾问题,综述了电池内部热失控演变过程、热失控气体释放及其燃爆风险,以及热失控和火灾发生时有毒有害气体的危害性等方面近年来的研究进展.最后提出今后主要研究方向是电池模块/电池包内热失控气体释放和流动过程研究、气体爆炸危险性动态变化规律研究和大容量高比能富镍电池单体/模块热失控特性和规律研究等.     

锂离子电池热解气体爆炸极限测定及其危险性分析

为定量研究锂离子电池热失控的危险性,利用锂离子电池在滥用条件下释放气体的种类及体积分数,计算锂离子电池热解气体爆炸极限并研究锂电池荷电状态对热解气体爆炸极限的影响。结果表明:在一定热失控条件下锂离子电池荷电状态为100%时其热解气爆炸下限为6.22%,上限为38.4%,在相同热失控条件下,锂离子电池热解气体的爆炸极限范围随着荷电状态的升高而增大,锂电池的荷电状态对热解气体的爆炸上限影响较大而对爆炸下限影响较小。在相似条件下,锂离子电池热解气体的爆炸极限范围比普通烃类气体大,一旦锂电池发生热失控会对锂离子电池运输造成潜在威胁。     

苯和甲苯硝化及磺化反应热危险性分级研究

首先介绍了化工工艺热安全性的内涵,并从反应过程热危险性分析的方法学出发,介绍间隙、半间歇化学反应工艺热危险性分级研究的总体思路及方法。然后,围绕甲苯和苯的硝化、磺化反应,用全自动反应量热仪(RC1e)和加速度量热仪(ARC)测定其反应过程的绝热温升(△Tad)、目标反应所能达到的最高温度(TM)、分解反应最大速率到达时间(θD)等参数。运用风险评价指数矩阵法(方法1)和基于失控过程温度参数的热危险评估法(方法2)分别对其硝化和磺化反应过程的热危险性进行了分级评估。结果表明,这两种方法具有良好的一致性;给定工艺条件下甲苯和苯的一段硝化反应过程的热危险度等级较低;而磺化反应的热危险较高。尽管这两种方法还有一定的局限性,但对于间歇、半间歇合成工艺的本质安全化设计、工艺热危险性的评估具有重要的参考价值和实用意义。     

Inherent thermal runaway hazard evaluation method of chemical process based on fire and explosion index

Thermal runaway hazard assessment provides the basis for comparing the hazard levels of different chemical processes. To make an overall evaluation, hazard of materials and reactions should be considered. However, most existing methods didn't take the both into account simultaneously, which may lead the assessment to a deviation from the actual hazard. Therefore, an integrated approach called Inherent Thermal-runaway Hazard Index (ITHI) was developed in this paper. Similar to Dow Fire and Explosion Index(F&EI) function, thermal runaway hazard of chemical process in ITHI was the product of material factor (MF) and risk index (RI) of reaction. MF was an indicator of material thermal hazards, which can be determined by initial reaction temperature and maximum power density. RI, which was the product of probability and severity, indicated the risk of thermal runaway during the reaction stage. Time to maximum rate under adiabatic conditions and criticality classes of scenario were used to indicate the runaway probability of the chemical process. Adiabatic temperature rise and heat of the desired reaction and secondary reaction were used to determine the severity of runaway reaction. Finally, predefined hazard classification criteria was used to classify and interpret the results obtained by this method. Moreover, the method was validated by case studies.     

Probe into effect of the initiator on the thermal runaway hazards of methyl methacrylate bulk polymerization

The bulk polymerization of methyl methacrylate (MMA) is of great importance in chemical industry, but the polymerization process is highly hazardous, and few reports have focused on the effect of initiators on its thermal hazards. In this work, to thoroughly explore the thermal hazard characteristics, the runaway behavior of MMA bulk polymerization is investigated by a combination of thermodynamics experimental and kinetics theoretical methods. The results indicate that the presence of initiator exhibits an undesirable thermal hazard to the MMA bulk polymerization, and its exothermic behavior is also greatly influenced by the type and concentration of initiator. For azobisisoheptanenitrile (ABVN), azodiisobutyronitrile (AIBN) and dibenzoyl peroxide (BPO) initiators as examples, the AIBN-initiated reaction has the shortest adiabatic induction period (39.51 min), whereas the BPO-initiated polymerization exhibits the strongest maximum temperature-rising rate and maximum pressure-rising rate. Under adiabatic runaway, the temperature and pressure change significantly with increasing AIBN concentration, revealing a great potential risk of thermal runaway. Kinetic parameters are calculated to further understand the thermal runaway mechanisms, showing a strong agreement with the adiabatic experimental data. Finally, based on the cooling failure scenario, severity grading is determined by the evaluation criteria. The current work provides extensive data as a reference and guidance for the process design and optimization of MMA bulk polymerization from the perspective of safety.     

Investigation of the decomposition reaction and dust explosion characteristics of crystalline dicumyl peroxide

The dicumyl peroxide (DCP) is widely used as a polymerization initiator, catalyst and vulcanizing agent in the chemical industry. A number of accidents have been caused by its thermal instability in storage or manufacturing process. Thus, its hazard characteristics have to be clearly identified. First of all, the differential scanning calorimeter (DSC) is used to measure the heat of decomposition reaction, which can contribute to understanding the reaction characteristics of DCP. The accelerating rate calorimeter (ARC) is used to measure the rates of temperature and pressure rises of decomposition reaction, and then the kinetics parameters are estimated. Furthermore, the MIKE 3 apparatus and the 20-l-Apparatus are used to measure and analyze the dust explosion characteristics of DCP at room temperature and atmospheric pressure. Finally, Semenov's thermal explosion theory is applied to investigate the critical runaway condition and the stability criterion of decomposition reaction, and to build the relationship of critical temperature, convective heat transfer coefficient, heat transfer surface area and ambient temperature. These results contribute to improving the safety in the reaction, transportation and storage processes of DCP.     

The runaway scenario in the assessment of thermal safety: simple experimental access by means of the catalytic decomposition of H2O2

The runaway scenario can serve as a basis for the assessment of thermal process risks. In this context, the time to maximum rate (TMR_ad), i.e., the time between cooling failure and thermal explosion, can be a measure of the time in which safety measures must be taken. This paper highlights the discussion of TMR_ad by presenting the catalytic decomposition of hydrogen peroxide with potassium iodide. The experimental procedure is easily practicable and imposing for the students. An overview of the theoretical background is given before presenting the experiment.     

反应失控型火灾爆炸事故预测

介绍了一种预测反庆失控灾害的方法,通过实验测定容器的时间常数,预测能够引起反应失控的最低环境温度,发生反应失控时的危险温度,以及达到最大反应速度反需的时间,预测结果与实际情况具有良好的一致性。     

Thermal risk in batch reactors: Case of peracetic acid synthesis

The present paper deals with accidents risk in batch reactors. It identifies the conditions for the occurrence of a thermal runaway and develops a probabilistic approach to assess the relevant risk. It investigates also the conditions for optimal synthesis of peracetic acid (PAA) with hydrogen peroxide (HP) and acetic acid (AA). The kinetic model of reversible reaction and side reaction of PAA synthesis is used to predict reactor temperature and molar ratio of PAA by ASPEN PLUS software. A sensitivity analysis is performed under different conditions such as constant temperature or adiabatic process with different concentrations of sulfuric acid. Assuming a prior cooling system failure, the conditions for reaction runaway triggering a thermal accident are identified in the case of PAA synthesis. Monte Carlo simulations are used in order to calculate the conditional probability of accident and optimize the synthesis of PAA.     

Thermal risk in batch reactors: Theoretical framework for runaway and accident

Thermal safety and risk of accidents are still challenging topics in the case of batch reactors carrying exothermic reactions. In the present paper, the authors develop an integrated framework focusing on defining the governing parameters for the thermal runaway and evaluating the subsequent risk of accident. A relevant set of criteria are identified in order to find the prior conditions for a thermal runaway: failure of the cooling system, critical temperature threshold, successive derivatives of the temperature (first and second namely) vs. time and no detection in due time (reaction time) of the runaway initiation. For illustrative purposes, the synthesis of peracetic acid (PAA) with hydrogen peroxide (HP) and acetic acid (AA) is considered as case study. The critical and threshold values for the runaway accident are identified for selected sets of input data. Under the conditional probability of prior cooling system failure, Monte Carlo simulations are performed in order to estimate the risk of thermal runaway accident in batch reactors. It becomes then possible to predict the ratio of reactors, within an industrial plant, potentially subject to thermal runaway accident.     

常压及低压下锂电池热失控随数量变化特性

为明确在地面常压环境和商用飞机巡航高度低气压环境下锂电池热失控火灾危险特性随电池数量的变化关系,分别于95 kPa地面常压环境和20 kPa低压环境下,开展不同电池数量梯度的热失控试验,测量热释放速率,总热释放量,烟气温度,CO、CO2和碳氢等气体的实时体积分数.结果表明:最高热释放速率和总热释放量与电池数量均呈幂函数...