石化行业中某些碳氢燃料爆炸危险性分析

借助于激波管测定了几种碳氢燃料和空气混合物的爆轰极限、临界起爆能。根据这些实验数据，分析了所研究的碳氢燃料的爆炸危险性。同时根据烷烃和烯烃键的不同饱和度，分析了它们爆炸危险性差别的原因。     

浅谈提高爆炸容器使用安全性的技术措施

针对爆炸容器工作时 ,产生的爆炸冲击波、破片、有害气体、振动及噪声等危害因素 ,简述了国内外使用爆炸容器时 ,采取的一些相关安全技术措施 ;提出了将结构健康监测技术应用于爆炸容器寿命安全评估的构想     

热爆炸理论在粉尘爆炸机理研究中的应用

笔者对粉尘爆炸的几种机理进行了简要分析 ,认为粉尘爆炸是由热爆炸引起的。在对粉尘燃烧过程作了较为合理的假设后 ,将热爆炸理论中均温系统的热爆炸判据 ,应用于粉尘爆炸中 ,得出了爆炸下限与粉尘粒径呈线性关系的结论 ,且与实验符合 ,并推导出粉尘的热爆炸判据。结果表明 :用热爆炸理论来解释粉尘爆炸机理是可行的。     

A new simple methodology for evaluation of explosion risk in underground coal mines

The key objective of this paper is the presentation of a new risk assessment tool for underground coal mines based on a simplified semi-quantitative estimation and assessment method.In order to determine the risk of explosion of any work process or activity in underground coal mines it is necessary to assess the risk. The proposed method is based on a Risk Index obtained as a product of three factors: frequency of each individual scenario P_ucm, associated severity consequences C_ucm and exposure time to explosive atmospheres E_ucm. The influence of exposure time is usually not taken into account up to now. Moreover, the exposure to explosive atmospheres may affect factors of hazardous event probability as much as its consequences. There are many definitions of exposure to explosive atmospheres but in the case of underground coal mines the exposure is defined as frequency risk of firedamp and coal dust. The risk estimation and risk assessment are based on the developed of a risk matrix.The proposed methodology allows not only the estimation of the explosion risk but also gives an approach to decide if the proposal investment is well-justified or not in order to improve safety.     

Explosion pressure prediction via polynomial mathematical correlation based on advanced CFD Modelling

Computational Fluid Dynamics CFD can be used as a powerful tool supporting engineers throughout the steps of the design. The combination of CFD with response surface methodology can play an important role in such cases. During the conceptual engineering design phase, a quick response is always a matter of urgency. During this phase even a sketch of the geometrical model is rare. Therefore, the utilisation of typical response surface developed for congested and confined environment rather than CFD can be an important tool to help the decision making process, when the geometrical model is not available, provided that similarities can be considered when taking into account the characteristic of the geometry in which the response surface was developed. The present work investigates how three different types of response surfaces behave when predicting overpressure in accidental scenarios based on CFD input. First order, partial second order and complete second order polynomial expressions are investigated. The predicted results are compared with CFD findings for a classical offshore experiment conducted by British Gas on behalf of Mobil and good agreement is observed for higher order response surfaces. The higher order response surface calculations are also compared with CFD calculations for a typical offshore module and good agreement is also observed.     

Explosion hazards related to hydrogen releases in nuclear facilities

Hydrogen explosion risk needs to be carefully assessed and evaluated in nuclear facilities because of the potential catastrophic consequences: breakdown of safety equipments, failure of containment, dissemination of radioactive materials in the environment.When studying an indoor release, one possible simplification is to assume a perfect gas mixing inside the room. This assumption is effectively often used to evaluate toxic risks in the environment outside a building (Mastellone, Ponte, & Arena, 2003). However, perfect gas mixing assumption is only a rough approximation, as indoor concentrations can largely differ from mean values, due to buoyancy, recirculation zones or obstacles for example.In order to better evaluate the risk of explosion in case of an accidental release of hydrogen, IRSN conducted a numerical study using FLACS CFD software. Several parameters have been studied to identify dangerous situations and draw a representative picture of the risk: room size, position and direction of hydrogen leak, ventilation characteristics. Hydrogen release flow rates used for numerical simulations have been chosen as the highest leak rate which, by applying the assumption of perfect mixing, produces an average concentration in the room equal to hydrogen lower flammability limit (LFL).Simulation results indicate that in some particular configurations, especially for impinging hydrogen jets, hydrogen concentrations can locally be above LFL and then create explosive atmospheres with significant volumes.     

Risk assessment method of polyethylene dust explosion based on explosion parameters

The explosion characteristic parameters of polyethylene dust were systematically investigated. The variations in the maximum explosion pressure (P_max), explosion index (K_st), minimum ignition energy (MIE), minimum ignition temperature (MIT), and minimum explosion concentration (MEC) of dust samples with different particle sizes were obtained. Using experimental data, a two-dimensional matrix analysis method was applied to classify the dust explosion severity based on P_max and K_st. Then, a three-dimensional matrix was used to categorize the dust explosion sensitivity based on three factors: MIE, MIT, and MEC. Finally, a two-dimensional matrix model of dust explosion risk assessment was established considering the severity and sensitivity. The model was used to evaluate the explosion risk of polyethylene dust samples with different particle sizes. It was found that the risk level of dust explosion increased with decreasing particle size, which was consistent with the actual results. The risk assessment method can provide a scientific basis for dust explosion prevention in the production of polyethylene.     

石化行业控制室承爆风险评估方法研究

针对传统的气体爆炸风险评估方法的不足之处,提出采用一种基于CFD技术的气体爆炸风险评估方法,对某煤气化厂区氢气爆炸对控制室造成的风险进行模拟计算与预测分析。并把研究结果与传统的TNT当量法、Multi-Energy方法预测结果进行比较。结果表明,该方法能考虑到密集管道与复杂装置布局、气云大小等因素对爆炸超压的影响,且能用于超压波的近场预测,以及确定空间不同位置处的爆炸超压,更适用于石化行业控制室的承爆风险评估。     

道氏火灾爆炸指数法在化工品码头危险性评价中的应用

简要介绍了道氏火灾爆炸指数法（第６ 版）的评价过程，并应用该方法对某化工品码头储运生产各工艺环节的火灾爆炸危险性进行了评价。     

A methodology to predict shock overpressure decay in a tunnel produced by a premixed methane/air explosion

A methodology for estimating the blast wave overpressure decay in air produced by a gas explosion in a closed-ended tunnel is proposed based on numerical simulations. The influence of the tunnel wall roughness is taken into account in studying a methane/air mixture explosion and the subsequent propagation of the resulting shock wave in air. The pressure time-history is obtained at different axial locations in the tunnel outside the methane/air mixture. If the shock overpressure at two, or more locations, is known, the value at other locations can be determined according to a simple power law. The study demonstrates the accuracy of the proposed methodology to estimate the overpressure change with distance for shock waves in air produced by methane/air mixture explosions. The methodology is applied to experimental data in order to validate the approach.     

FREEDOM II: An improved methodology to assess domino effect frequency using simulation techniques

The uncertainty and the complexity associated with the domino effect is a barrier to assessing the frequency of such accidents analytically. The use of simulation techniques, such as Monte Carlo, to examine the domino effect instead of analytical techniques has shown great promise. In this paper, a new method to assess the frequency of domino accidents is proposed—FREEDOM II—which is an improvement on the recent algorithm proposed by the authors (FREEDOM). The modifications on FREEDOM were carried out to overcome a limitation of the method and to extend its capabilities. A key shortcoming of the earlier method was its inability to handle multiple failure scenarios. This shortcoming has been overcome in FREEDOM II. A new and improved algorithm has been developed that carries out the simulation in a significantly shorter run time. The applicability of the new model is shown by performing a multi-scenario case study.     

An integrated methodology to manage risk factors of aging urban oil and gas pipelines

Aging urban oil and gas pipelines have a high failure probability due to their structural degradation and external interference. The operational safety of the aging urban oil and gas pipeline is challenged by different hazards. This paper proposes a novel methodology by integrating an index-based risk evaluation system and fuzzy TOPSIS model for risk management of aging urban oil and gas pipelines, and it is carried out by evaluating the priority of hazards affecting pipeline safety. Firstly, the hazard factors of aging urban oil and gas pipelines are identified to establish an index-based risk evaluation system. Subsequently, the fuzzy TOPSIS model is employed to evaluate the importance of these hazard factors and to decide which factors should be managed with priority. This work measures the importance of a hazard factor from three aspects, i.e. occurrence (O), severity (S) and detectability (D), and the weights of these three parameters are determined by a combination weight method. Eventually, the proposed methodology is tested by an industrial case to illustrate its effectiveness, and some safety strategies to reduce the operational risk of the pipeline are presented. The proposed methodology is a useful tool to implement more efficient risk management of aging urban oil and gas pipelines.     

A methodology to clarify logical relationship among failure modes and determine system probabilities

In the vulnerability analysis, correlations among failure modes have significant effects on the estimation of failure probabilities. However, the failure modes were assumed to be independent with each other or only parts of dependencies of failure modes were considered, which might lead to inaccurate results. In the present study, a novel methodology to clarify the entire logical relationship among failure modes and determine system probabilities is developed. Firstly, based on the form-changed limit state equations (LSEs) of failure modes, the LSE surfaces or curves are plotted. Subsequently, the logical relationship among failure modes can be identified with the LSE surfaces or curves. The system consequences are further developed by the logical relationship. Bayesian network (BN) is constructed with the input of logical relationship into arcs. With BN considering logical relationship, the occurrence probabilities of failure modes are calculated and system probabilities are estimated more accurately, which are verified well with Monte Carlo simulation and analytical solution. Furthermore, the detailed compositions of occurrence probabilities of failure modes are specified by the system probabilities. The methodology is illustrated by a case study. This study can be applied to the vulnerability analysis of various hazards or disasters as long as LSEs for corresponding failure modes can be developed.     

建筑物火灾危险性评估的一种工程方法

提出了建筑物火灾危险性评估的一种工程方法。该方法基于建筑火灾的区域模拟理论和人员疏散的最新研究成果，分别计算出火灾中达到危险状态的时间和整个疏散过程所需的时间，通过对比这两个时间，来确定火灾危险性的大小。这种方法概念清晰，简单易行，能在一定程度上对实际建筑物的火灾危险性进行评估，也可用于对火灾的安全工程设计评价和安全咨询。     

An improved methodology for assessing risk in aircraft operations at airports, applied to runway overruns

The paper addresses the need for models to assess risk at any particular airport, based on risk management principles used by the present risk management process, that use all available data on previous accidents. The case of runway overruns is taken as an example application, because new regulations require the provision of much longer Runway End Safety Areas than had previously been the norm. The paper presents models for overruns arising from both landings and aborted takeoffs. In each case models of overrun risk, of wreckage location and of the consequences are detailed. An example application of the models is then given in a hypothetical risk assessment.The models, though adding value to existing methods of assessing risk, are not as good as they could be, due to the lack of data on normal operations. It was therefore possible only to relate the rate of overruns to the rate of occurrence of the possible driving factors for a few factors where such comparable data on normal operations existed. It is recommended that effort be put into the collection of data to allow a more comprehensive analysis.     

Risk analysis of a cross-regional toxic chemical disaster by using the integrated mesoscale and microscale consequence analysis model

The rapidly growing capacity and scale of the world's petrochemical industries have forced many plants to have an even larger amount of hazardous substances. Once a serious leak occurs, the outcome of the effect zone could be very large or even uncontrollable just like the Bhopal disaster. In order to assess the risk of a cross-regional damage, this study aims to develop a model that can combine the benefits of both CFD model of the microscale simulation and the Gaussian dispersion model of the mesoscale simulation.The developed integrated model is employed on a toxic chemical tank leak accident of a process plant within an industrial park in order to explore the consequences and the risk of the toxic gas dispersion on three different scopes; one is the accident site, the second is the long-distance transmission route of the mesoscale area and the third is a target city. According to the simulation's results, it is obvious that the complexity of the structure surrounding the leaking tank will eventually affect the maximum ground concentration, the cloud shapes and cloud dilution rate, while the released gas is under dispersion. On the other hand, since the simple Gaussian dispersion model doesn't consider the above impacts, its calculation results will have many differences as compared to the realistic situation. This integrated model can be used as a tool for estimating the risk on a microscale or mesoscale areas and it can produce better results when an environmental impact analysis is required for a larger hazardous chemical process.     

液化石油气瓶站气体泄漏爆炸危险性研究

针对某个城市居民区的液化气瓶站,采用数值模拟方法计算在液化气钢瓶发生泄漏后,液化石油气发生爆炸对瓶站和周围建筑的冲击波和温度的影响;分析冲击波对建筑可能造成的损坏情况;根据模拟分析结果,提出了改进液化气瓶站安全性的技术措施。笔者计算和分析的结果及提出的安全技术措施,为保障周围建筑和人员安全提供了技术依据。     

An overview to CERSSO's self evaluation of the cost-benefit on the investment in occupational safety and health in the textile factories: "a step by step methodology"

INTRODUCTION: The Pan American Health Organization (PAHO) and CERSSO collaborated to develop a new Tool Kit (TK), which became available in May 2002. PAHO already had a TK in place, and CERSSO requested that one be developed for their needs. CERSSO wanted to enable managers and line workers in garment factories to self-diagnose plant and workstation hazards and to estimate the costs and benefits of investing in occupational safety and health (OSH) as a way to improve productivity and competitiveness. METHODS: For consistency, the collaborating organizations agreed to construct the TK according to PAHO's methodology. The instrument was developed to be comprehensive enough that any user can collect the data easily. It integrates epidemiologic, risk assessment, clinic, engineering, and accountability issues, organized to include step-by-step training in: (a) performing risk assessments in the workplaces (risk factors); (b) making cause-effect relationships; (c) improving decision making on OSH interventions; (d) doing calculations of direct and indirect costs and savings; and (e) doing calculation of the overall cost-benefit of OSH interventions. RESULTS AND CONCLUSIONS: Since July 2002, about 2,400 employees and officials from 736 garment factories, Ministries of Labor, Health, Social Security Institutes, and Technical Training Institutions of Central America and the Dominican Republic have used this instrument. Systematically, they have calculated a positive relationship of the investment (3 to 33 times). Employers are now aware of the financial rewards of investing in OSH. The TK is available in Spanish, Korean, and English. In July 2003, a software program in Spanish and English was developed (180 persons have been trained in the region), which requires less time to execute with better reliability.     

Three accidents in European dynamite production plants: An attempt to improve the external lessons learning

Three serious accidents occurred in three dynamite manufacturing plants within three European countries during a relatively short time period triggering the question of effective external learning. The article discusses the lessons for the prevention of accidents learned from retrospective comparative analysis. It advocates for a better process for learning lessons. It attempts to show how a two level approach to accident analysis may help to reveal a common deeper learning hidden under diverse routine lessons.