注氮辅助蒸汽吞吐工艺过程井筒爆炸事故分析方法

在注氮气辅助蒸汽吞吐开采原油的工艺过程中,由于地层条件复杂,存在发生油井爆炸事故的风险.以某油田注氮作业过程的井筒爆炸事故为例,结合现场调研和理论计算分析了事故的爆炸性质和点火源类型.通过对物理爆炸和化学爆炸的爆炸能量和爆炸压力进行理论计算,结合本次爆炸事故的总能量及井口装置的破坏压力,确定此次井筒爆炸事故类型为化学爆炸.此外,通过对比分析3种不同类型的点火源,确定此次井筒爆炸事故的点火源为注气速度过快导致油套管相互碰撞产生的碰撞火花.通过全面分析某油田井筒爆炸事故原因和性质,形成了一种系统性的井筒爆炸事故分析方法.     

水煤浆管道爆炸事故机理分析

某化工厂水煤浆管线因误操作发生管道爆裂,造成人员死亡和财产损失.根据事故发生过程,从化学、物理角度分析了事故发生的机理.研究表明,该起水煤浆管道爆炸事故是物理爆炸和化学爆炸共同作用的结果,回流的高温合成气和化学爆炸产生的高温使水煤浆产生物理变化,从而诱导和加剧了物理爆炸.物理爆炸产生的超压是管道破裂的主要原因.     

氢氧混合气体爆炸临界条件实验研究

可燃气体的燃烧、爆炸是工业生产中常见的灾害性事故,危害极大.通过爆轰管实验装置,采用疏密分布的压力传感器测量氢氧混合气体的爆轰特性,并依据压力和波速在燃烧转爆轰瞬间发生突跃,判断混合气体爆炸的临界条件.实验结果表明,爆炸压力随氢气初始浓度呈∩形变化,50%氢气体积分数为爆炸最佳浓度值;在常温常压下,氢氧混合物爆炸的临界氢气体积分数是15%和90%;化学计量比的氢氧混合气体发生爆炸的临界初始压力为0.01 MPa;氮-氢-氧三元混合气体爆炸的临界氮气体积分数为60%.     

过氧化氢生产装置爆炸——化学分解后的物理过程研究

过氧化氢的不稳定性使得其在生产过程中较容易发生爆炸事故.为了预防事故的发生,需要对其分解爆炸过程有个清晰的认识.本文首次利用典型事故爆炸机理分析结合事故定量计算的方法,揭示了事故案例中过氧化氢化学分解后引起爆炸的两个物理过程,计算了产生事故后果的容器失效压力,了解了其发生爆炸的后果严重度,并运用类比的方法,得到了过氧化氢生产装置或容器爆炸时的压力变化趋势.     

ABC干粉灭火器爆炸事故原因分析

通过化学分析、模拟试验和理论计算分析ABC干粉灭火器爆炸事故发生的原因.研究事故灭火器充装的ABC干粉灭火剂的性能、碳酸盐含量、生成气体种类、化学反应机理和爆破压力.结果表明,以磷酸铵盐为主料的ABC干粉灭火剂含有碳酸氢钠和碳酸钙,同时ABC干粉灭火剂存在含水率超标、吸湿性和斥水性不合格等质量问题.贮存期间,ABC干粉灭火剂中的磷酸铵盐可与碳酸氢钠、碳酸钙发生非预期化学反应,产生CO2,使灭火器筒体内压力升高,直至超过灭火器爆破压力,这是造成灭火器爆炸事故的根本原因.因此,生产实践中应科学配方、确保原材料质量、严格遵守生产工艺,以有效控制ABC干粉灭火剂质量和避免类似事故发生.     

一起铝合金氧气瓶爆炸案例分析

某小区居民家中发生一起铝合金氧气瓶爆炸事故,现场勘验发现爆炸现场有起火源及气瓶受到高温烘烤的痕迹。经分析气瓶爆炸的原因是瓶体受火导致材料强度急剧下降,而气瓶内气体压力逐渐升高达到气瓶的爆破压力而发生爆炸。为预防类似事故再次发生,建议铝合金无缝气瓶的安全泄压装置应要求是温度型与压力型（易熔合金塞与爆破片）的并联复合装置,防止因气瓶受火而发生瓶体爆炸事故。     

氧气瓶内附油脂充氧过程爆炸分析与计算

分析总结了氧气钢瓶物理爆炸和化学爆炸的原因。针对2009年某市发生的一起氧气瓶内含油脂爆炸事故,系统分析了国内曾经发生的几次因油脂导致气瓶爆炸事故。油脂进入到氧气瓶内大都是由于误操作。油脂与高压纯氧接触会发生剧烈的自燃氧化放热,使瓶内的氧气迅速升温升压,超出气瓶承压极限导致爆炸破裂。分析比较发现由油脂导致的气瓶爆炸,其破坏程度不如混入可燃气体导致的气瓶爆炸剧烈,一般不是粉碎性爆炸。在正常的充氧过程中,氧气瓶温度会升高,采用变质量热力学中的方法,计算说明气瓶在充装过程中氧气温度的具体变化。充氧温度计算为充氧工作人员提供参考,如发现异常情况,可以及时地控制和预防。由现场压力表可知氧气瓶在充装至12MPa时发生爆炸,而氧气瓶最小爆炸压力为37.6MPa,油脂燃烧放热,计算可知致使钢瓶爆炸破裂所需要的最小油脂量,为66.4-79.6g。不同的充装压力下发生爆炸,所需要的最小油脂量不同,充装压力越高,爆炸所需要的最小油脂量越少。     

尿素合成塔内化学爆炸机理分析

分析了尿素合成塔发生化学爆炸的可能性.利用经验公式计算出塔内上部空间气相在正常生产和非正常生产状态下的爆炸极限范围,并计算出非正常生产状态下气相化学爆炸产生的压力和能量范围.计算结果与现场数据吻合.爆炸所产生的压力作用于液面上,根据静压传递原理,尿液内各点与外压相等,超过尿塔正常工作压力,并导致破裂.     

常见烯烃爆炸特性的研究

为减少烯烃类爆炸事故带来的严重危害,采用国际通用的20L球型爆炸测试装置测试了常温初始压力为0.1 MPa条件下,4种常见烯烃的爆炸特性参数.结果表明,随着烯烃含量的增加各项爆炸特性参数均呈现出先增大后减小的特征,最大爆炸压力和爆炸指数均在化学计量比附近获得,4种烯烃最大爆炸压力分别为乙烯1.5 MPa、丙烯1.3 MPa、正丁烯1.5 MPa、异丁烯1.6 MPa,爆炸指数分别为16.56 (MPa·m)/s、7.37(MPa·m)/s、16.98 (MPa·m)/s、29.07(MPa· m)/s.     

事故树分析法在LPG储罐火灾爆炸事故中的应用

LPG(液化石油气)属于危险化学品之一,LPG储罐发生火灾爆炸的机率大,造成的损失比较严重,故对其火灾爆炸事故进行研究具有重要意义。LPG储罐爆炸根据其发生机理分为化学爆炸(燃爆)和物理爆炸两种模式。本文通过对LPG储罐燃爆﹑物理爆炸两类事故进行系统分析,建立了以LPG储罐燃爆、物理爆炸为顶事件的事故树。通过对其事故树的定性分析,得到了影响顶事件的各个最小割(径)集。通过计算底事件的结构重要度,确定了影响LPG储罐火灾爆炸事故的主要因素,并提出了相应的改进措施,进而提高LPG储罐的安全性和运行可靠性。     

Problems of railway noise-a case study

Under Directive 2002/49/EC relating to the assessment and management of environmental noise, all European countries are obliged to model their environmental noise levels in heavily populated areas. Some countries have their own national method, to predict noise but most have not created one yet. The recommendation for countries that do not have their own model is to use an interim method. The Dutch SRM II scheme is suggested for railways. In addition to the Dutch model, this paper describes and discusses 3 other national methods. Moreover, discrepancies between the HARMONOISE and IMAGINE projects are analysed. The results of rail traffic noise measurements are compared with national methods.     

A little knowledge is a dangerous thing – Unexpected reaction case studies make the case for technical discipline

The old saying, “what you don't know can't hurt you,” implies that ignorance is bliss. “A little knowledge is a dangerous thing,” may be closer to the truth; however, it is not the little that we know that is dangerous, but that which is not known. By design, the processes used in the chemical industry are reactive, and the intended reaction receives much scrutiny. However, other reactions occur, often unexpectedly, and possibly with severe consequences. The lessons we learn from these reactions must drive the improvement of our process development and technology management processes and the culture that shapes those processes, a culture of Technical Discipline.Technical Discipline, analogous to Operating Discipline in the manufacturing organization, is a culture committed to fully identifying and characterizing chemical and reaction hazards, and properly documenting and communicating those hazards to create a permanent knowledge and understanding within the organization operating that process.A culture of Technical Discipline will reveal reaction hazards that might otherwise remain unknown until being unveiled in a dramatic and unexpected fashion. Until you fully identify and characterize the hazards of the materials you handle in your processes…what you don't know can hurt you.     

Making hybrid mixture explosions a common case

Explosions of gas-dust hybrid mixtures have long been considered as particular cases encountered in specific industrial contexts. However, it should be reminded that during the explosion of an organic powder, the presence of a hybrid mixture composed of the dust itself and its pyrolysis gases is compulsory. On these premises, an experimental study to determine the role of cellulose pyrolysis products (gaseous, condensable and solid) on the global phenomenon is presented. Hybrid mixture explosion tests were exploited to carry out the investigation. The G-G furnace and the 20 L sphere were employed. Several experimental strategies were chosen to demonstrate the impact of pyrolysis reaction on the explosion of organic powders: i) the fuel equivalence ratio of the reactive mixture (case 1), or ii) the mass of reactants (case 2) were respectively kept constant, iii) the effects of water vapor, char and tar were tested. They were next compared to identify the most suitable one. The two first experimental approaches lead to significantly different results: only case 2 keeps the maximum explosion pressure almost constant, but maximum rate of pressure rises and deflagration index greatly decrease when the pyrolysis gases concentration decreases, which highlights the importance of the pyrolysis reaction on the explosion kinetics. It should also be stressed that the maximum explosion severity is not obtained for the pure gases but when a small dust content is added. The same evolution is observed when a small amount of char is introduced to pyrolysis gases, which underlines the influence of the radiative transfer. Adding small amounts of tar to cellulose tends to increase its explosion severity. However, this impact is less than that generated by the addition of pyrolysis gases.     

Some unusual case histories from personal experience

Is protection of equipment the only consideration when setting the relieving pressures of safety relief valves? I will show you a case where other factors should have been considered and suggest that you might give your safety valve set pressures a second thought.Do you have side-by-side pieces of identical equipment? If so, you must consider that operating or maintenance personnel may become confused, and the results maybe catastrophic. A PVC reactor incident will demonstrate this point.Does your process contain materials that could decompose? After thirty years of safe operation in butadiene units, there was a vinyl acetylene decomposition. Could it happen to you?It is my hope that these three unique and unusual cases will provide valuable information for operations and maintenance personnel, managers, safety professionals, and engineers.     

典型用电案例敲警钟

近年来,农村在生活、生产、防盗等用电中,由于少数农民缺乏电力法制观念、安全用电知识、思想麻痹大意,用电疏忽随意,导致触电伤亡事故屡有发生。不仅给生命财产带来重大损失,还严重影响电网安全运行。     

Methodology for case studies of accidental gas explosions

This paper discusses a procedure for case studies of accidental gas explosions. The procedure for each case study can be subdivided into four steps, i.e., collection of proofs, analyses, confirmation, and inference about the processes of the accident, and the issues in each step are pointed out. Making a guess on the sequence of the accident to be investigated should be avoided during collection of proofs. Misunderstanding of the phenomena in analyses and confirmation is likely caused by inappropriate knowledge on the phenomena and/or use of unsuitable models. The sequence of the accidental gas explosion should be inferred on the basis of confirmed processes. If there are other possibilities, those should be described in the report. The reasonableness of the results of a case study depends on the rationality of the procedure and the quality or plausibility of knowledge to infer the probable sequence.     

Risk-optimal highway design: Methodology and case studies

Highway geometric design in mountainous areas has been a typical challenge. The combination of short horizontal curves and restricted right-of-way is a common ground for contemplating design exception in British Columbia, Canada. In practice, collision modification factors (CMFs) are advocated as quantitative measures of changes in road features on safety. However, in many situations, there are no CMFs in the literature to predict the safety impact of changing particular road features. An important example of these road features is sight distance restriction on horizontal curves. A mechanism for risk measurement has been proposed in earlier work to assist designers in comparing the safety impact of different deviations from sight distance requirements. This paper attempts to answer the questions as to whether it is possible to reduce overall risk and achieve consistency in such reduction without demanding wider right-of-way. This problem was formulated in a multi-objective optimization framework. Following this methodology, it was possible to achieve an average reduction in risk of 25% on the nine critical cross-sections. This reduction in risk was achieved without demanding wider right-of-way and without creating measurable increase in expected collision frequency due to independent re-dimensioning of different geometric elements. On theoretical grounds, this paper represents another step into the direction of developing fully probabilistic geometric design standards. On practical grounds, this paper provides an important decision mechanism that enables the efficient use of available right-of-way for new highway construction. Case studies in this paper have been applied on a major highway development in British Columba, Canada.