A transportation network assessment tool for hazardous material cargo routing: Weighing exposure health risks,proximity to vulnerable areas,delay costs and trucking expenses

The inherent risks associated with accidental releases of hazardous materials during transport have drawn attention and concerns in the recent decades. The aim of this study is to propose a tool for evaluation and comparison of the transportation networks which can be used to assess the routing options between origins and destinations of the cargos for their suitability for transporting hazardous material cargos by tanker trucks and to identify routes which provide lower accidental release risks, lower public exposure risks, and offer economical benefits. Each route segment of transportation networks were evaluated using specific criteria which included health risk and cost of delay in case of an accidental release of materials, trucking cost and proximity to vulnerable areas. Since, the health impact of hazardous materials differ depending on the characteristics of the material being transported as well as release quantities and atmospheric conditions; this paper aimed in providing a tool that can be used to estimate the impact radius (for health risks) after accidental release of hazardous materials by taking into account different atmospheric conditions based on the meteorological data and solar elevation angle. The Gaussian air dispersion model paired with ArcGIS using Python programming were employed to estimate the health risk impact zones by considering the meteorological data, and accordingly to analyze road segments for cost impacts (delay and trucking costs), and the proximity to vulnerable areas. The route assessment tool was demonstrated with a case study. The results of this study can efficiently aid decision makers for transportation of hazardous materials.     

Real-time response system for the prediction of the atmospheric transport of hazardous materials

Human urge of exploiting earth resources has resulted into unprecedented industrial development in the last century resulting into production of large quantities of hazardous chemicals. Chemical, petrochemical, nuclear, biomedical and pharmaceutical industrial accidents release large quantities of hazardous chemicals into the atmosphere. The accidental discharge during production or storage or transportation have subjected the population to be exposed to exceptionally high concentration levels of hazardous chemicals, taking them by surprise, unprepared with fatal consequences. An emergency planning organization has to be trained to combat this situation in the shortest possible time to minimize the number of causalities. The present paper focuses on computation of dispersion model, using emission source, accident location and online metrological data near to the sources, to provide necessary and accurate results swiftly. The predicted ground level concentrations with the hazardous nature of the chemical, speed and direction of plume, the emergency team will be supplied with all the information in graphical easy to grasp form, superimposed over a GIS map or the latest satellite image of the area.

The emergency team has to be trained for all past scenarios and their preparedness, response and actions must be practiced regularly to be able to abate chemical releases accidentally or intentionally.

Accidental releases of chlorine and ammonia gases in residential and industrial areas are simulated. The predicted ground level concentrations in the effected areas are shown after different time intervals. For low vapor pressure chemical, the dispersion time is large and concentration levels are low but persist for prolonged time while for volatile chemical, the concentrations are high in short time and recovering to safe environment is quick.     

危险化学品泄漏扩散模型的研究现状分析与比较

为了对危险化学品港口装卸过程中泄漏危险度进行量化评定,基于泄漏扩散模型提高港口的应急处理技术,对危险化学品泄漏扩散模型的研究现状从理论研究、试验研究、应用研究3方面进行深入分析。着重对高斯模型(Gaussian model),BM模型,Sutton模型,FEM3模型,箱及相似模型,P-G模型等模型从理论描述方法、适用对象和范围、计算精度和难易、参数选取等方面进行优缺点的对比研究,认为:由于危险化学品泄漏和扩散行为的复杂性,影响因素的多样性,使各类模型在具备一定的理论价值和现实意义的同时,还存在着参数选取不确定性、试验模拟差异性以及实际应用局限性的问题和不足,运用计算机技术完善试验结果数据库、改进数学仿真模型是其进一步研究发展的趋势。     

Cushioning the impact of toxic release from runaway industrial accidents with greenbelts

The three aspects of accidents in chemical process industries which cause most serious damage—explosions, fires, and toxic releases—can all be controlled to some extent if greenbelts are present around the affected industry. We have recently developed and validated a system of methodologies for greenbelt design. In this paper we present the application of these models in designing greenbelts and forecasting their role in cushioning the impact of accidental release of toxic gases. With properly located and designed greenbelts as much as 33% of the accidental release of SO₂, 43% of H₂S, and 51% of NH₃ under stable atmospheric conditions (in which the dispersion is very slow and the release thus has maximum toxic impact) can be absorbed.     

A protocol for the evaluation of LNG vapour dispersion models

The international transport, storage and utilisation of LNG is growing rapidly. Whilst the LNG industry has an excellent safety record, the possibility of an accidental release cannot be discounted. Internationally-accepted standards, such as the 59A Standard of the US National Fire Protection Association (NFPA), provide direction on the assessment of LNG spill hazards and hazard range criteria which must be met. Modelling of the atmospheric dispersion of LNG vapour from accidental spills is one of the critical steps in such hazard analyses. This paper describes a comprehensive evaluation protocol devised for the 59A Standard, specifically for the assessment of LNG vapour dispersion models. The evaluation protocol is based on methodologies developed in previous European Union studies, which have been extended, significantly adapted and tailored to the specific requirements of the evaluation of models for the dispersion of LNG vapour. The protocol comprises scientific evaluation of the numerical and physical basis of models for the dispersion of LNG vapour, model verification, and validation; resulting in a comprehensive model evaluation report which includes qualitative and quantitative criteria for model acceptance. A supporting suite of validation data, and guidance on the use of this data, has also been produced. The NFPA 59A (2009) standard states that LNG vapour dispersion models are acceptable for use if they have been evaluated in accordance with this protocol.     

危险化学品企业实施安全评价工作绩效分析

2006年安全生产工作取得了较好的成绩,呈现总体稳定趋向好转的发展态势,事故死亡人数总量也较大幅度下降。但是,在危险化学品行业非但没有得到扭转,事故死亡人数反而上升了16.2%。对此,我们有必要加强对危险化学品的安全管理。在安全评价方面,危险化学品企业实施安全评价后是否对企业的发展有实际的绩效,对此,我们对全国320家实施过安全评价的危险化学品企业进行了调研分析,尤其在安全设施、安全管理水平、事故发生频率等方面,并从中得出结论,进而了解评价过程中存在的不足,以及提出合理的对策措施。     

Influence of wind speed profile and roughness parameters on the downwind extension of vulnerable zones during dispersion of toxic dense gases

The accidental release of toxic chemicals, which are heavier than air and stored under pressure, may create an emergency scenario in an industrial plant. The extension of vulnerable distance in the downwind direction is an important criterion in framing an emergency management plan of that industrial area. There are several studies showing the role of surface level meteorological and topographical features on its propagation and dispersion just after its release from a container. In the present study, vertical variation of wind speed in the atmospheric boundary layer and surface roughness parameter have been considered to study their roles on the impact of downwind extension of vulnerable distances. A catastrophic release from a tonner having 900 kg of liquid chlorine has been considered, and SAFETI Micro developed by DNV Technica, UK has been utilized in the consequence analysis of this release. The analysis results have been explained for various atmospheric stability classes and surface wind speeds.     

基于ARIMA-LOESS模型的危化品道路运输事故起数预测

文章针对危化品道路运输事故预测问题,运用差分自回归移动平均模型(Autoregressive Integrated Moving Average,ARIMA)与局部加权回归模型(Locally Estimated Scatterplot Smoothing,LOESS)的组合模型,对我国危化品道路运输事故发生起数进行预测。首先,基于2011—2018年我国发生的危化品道路运输事故数据建立ARIMA模型,利用SPSS软件进行模型拟合预测,获取危化品道路运输事故起数的线性部分;其次,应用MATLAB建立LOESS回归模型,对ARIMA模型预测偏差进行残差优化,获取危化品道路运输事故起数的非线性部分;最后,建立ARIMA-LOESS组合模型,利用组合模型对危化品道路运输事故发生起数进行预测,并根据真实数据对预测结果进行对比验证。结果表明:ARIMA-LOESS组合预测模型可较好拟合危化品道路运输事故数据序列,并修正单一模型的误差,获取较高的预测精度。该研究可为危化品道路运输安全与运行的趋势分析与判断提供更加可靠的数据依据,也可为危化品道路运输事故防控方案提供帮助。     

基于文献计量的国内危险化学品信息化监管主题与热点分析*

为提升危化品安全信息化监管建设能力与本质安全水平,通过文献计量法和CiteSpace软件,采用关键词共现和聚类归纳对危化品领域及技术研究趋势进行分析。结果表明:危化品安全信息化监管研究自1998年共经历萌芽、发展、摆动3个阶段,但高质量成果较少;在当前新兴信息技术和传统评价分析技术相结合的新型研究模式下,着重突出物联网、大数据、人工智能、区块链等智能技术占比,是未来危化品信息化监管发展重要途径。     

Influence of active mitigation barriers on LNG dispersion

In recent years, particular interest has been direct to the issues of risk associated with the storage, transport and use of Liquefied Natural Gas (LNG) due to the increasing consideration that it is receiving for energy applications. Consequently, a series of experimental and modeling studies to analyze the behavior of LNG have been carried out to collect an archive of evaporation, dispersion and combustion information, and several mathematical models have been developed to represent LNG dispersion in realistic environments and to design mitigation barriers.This work uses Computational Fluid Dynamics codes to model the dispersion of a dense gas in the atmosphere after accidental release. In particular, it will study the dispersion of LNG due to accidental breakages of a pipeline and it will analyze how it is possible to mitigate the dispersing cloud through walls and curtains of water vapor and air, also providing a criterion for the design of such curtains.     

重气连续泄漏扩散的风洞模拟实验与数值模拟结果对比分析

将重气连续泄漏的风洞模拟实验结果与SLAB重气扩散模型的预测结果进行了对比 ,分析了实验结果与模型预测结果的一致性 ,剖析了重气连续扩散的特点 ,特别是风速对重气连续泄漏扩散的影响 ,提出了在风洞模拟实验及扩散模型方面下一步应做的工作     

HGSYSTEM: a review, critique, and comparison with other models

HGSYSTEM is a package of computer models for modeling release and atmospheric dispersion of hazardous substances, which has capabilities that may not be found together elsewhere (e.g., hydrogen fluoride/air/water thermodynamics, aerosol release, release and dispersion of mixtures, multi-component evaporation, downward vertical jets, plume lift-off, deposition, and street-canyon). There are, however, some shortcomings in its spill models and in the transition from a spill to a dispersion model. The model's strong and weak points and limited comparisons with ALOHA and DEGADIS are discussed herein.     

Quantitative risk assessment model of hazardous chemicals leakage and application

The hazardous chemical accidents remain a matter of major concern. However, there is a dearth of practical measures about the emergency management of hazardous chemicals leakage. Therefore, in order to provide more accurate management plan, quantitative risk assessment has become a critical issue in chemical industry. The main aim of this study is to quantify the risk of hazardous chemicals leakage, and take precautions against the accidents. In this study, a Fire-Explosion-Poisoning Quantitative Probability Model (FEPQPM) has been established. The paper introduced the probability analysis methods to analyze derivative accidents caused by hazardous chemicals leakage, established quantitative risk assessment models, and made acceptable risk level analysis. This model has been applied to quantitatively assess an enterprise’s storage tank at Changshou Chemical Industrial Distripark (CID) in Chongqing, China. Evaluation results are in line with the actual situation of the CID. It is shown that the probability of poisoning is very large, causing more economic loss than the other two types of accidents, and death toll of leakage accident increases over time, resulting in greater economic losses. The risk level of leakage accident involving poisoning is unacceptable.     

TORAP—a new tool for conducting rapid risk assessment in petroleum refineries and petrochemical industries

The use of a new computer-automated tool TORAP (TOol for Rapid risk Assessment in Petroleum refinery and petrochemical industries) is demonstrated through a rapid and quantitative risk assessment of a typical petroleum refinery. The package has been applied for an appraisal of the risks of accidents (fires, explosions, toxic release) posed by different units of the refinery, and to identify steps to prevent/manage accidents. The studies reveal that TORAP enables a user to quickly focus on the accidents likely to occur, and enables forecasting the nature and impacts of such accidents. This information is directly utilisable in identifying “soft” spots and in taking appropriate remedial measures to prevent or control accidents. The special attributes of TORAP are: (a) a wide range of applications—achieved by incorporating models capable of handling all types of industrial fires and explosions, (b) sophistication—brought about by including state-of-the-art models developed by these authors and others, (c) user-friendliness—achieved by incorporating on-line help, graphics, carefully formatted output, and, above all, an automatic module with which even a lay user can conduct risk assessment. The entire package, especially its automatic module, is supported by an extensive knowledge-base built into the software.     

Advanced multi-perspective computer simulation as a tool for reliable consequence analysis

Major accidents involving hazardous materials are a crucial issue for the chemical and process industries. Many accidental events taken place in the past showed that dangerous substances may pose a severe threat for people and property. Aiming at loss prevention, a series of actions have been instituted through international regulations concerning hazardous installations safety preparedness. These actions involve efficient land-use planning, safety studies execution, as well as emergency response planning drawing up. A key factor for the substantial consideration of the above is the effective prediction of possible accident forms and their consequences, for the estimation of which, a number of empirical models have been developed so far. However, (semi-)empirical models present certain deficiencies and obey to certain assumptions, thus leading to results of reduced accuracy. Another approach that could be used for this purpose and it is discussed in this work, is the utilization of advanced computational fluid dynamics (CFD) techniques in certain accident forms modeling. In particular, composite CFD-based models were developed for the simulation of several characteristic accident forms involving isothermal and non-isothermal heavy gas dispersion, confined and unconfined explosion in environment of complex geometry, as well as flammable cloud fire. The simulation cases were referred to real-scale trials allowing us to conclude about the validity of the quantitative results. Comparisons of the computational predictions with the experimental observations showed that obtained results were in good agreement with the experimental ones, whereas the evaluation of statistical performance measures proved the simulations to be statistically valid.     

化学品突发性事故预测的不确定性分析

介绍化学品突发性事故预测的不确定性概率统计和模糊数学分析方法。对参数和模式的不确定性分别进行了讨论,计算机系统包括化学品常用数据库、事故识别模块,事故后果分析模块和不确定性分析模块,对液氯泄漏排放事故、液化气（丙烷）两相闪蒸爆炸和管道煤气（CO）泄漏伤害模式实例进行了分析。对连续源和瞬时源的讨论说明泄漏时间的确定对事故分析极为重要。     

Concentration model for gas releases in buildings and the mitigation effect

In case of accidents involving releases of hazardous materials, calculating the gas dispersion is essential for assessing risks. In general, the leaked chemical is assumed to be instantly dispersed to the atmosphere if the leak occurs in the outdoor location. However, a different approach should be made for the incidents when sources are located inside a building. For the indoor release, the gas will be diluted prior to the release to the atmosphere and the gas release from a building to the atmosphere demands the application of another model before the dispersion calculation. The indoor release model calculates average indoor concentration and volumetric flowrate to the exterior. The model is fast and reasonably accurate compared to rigorous but time-consuming computational fluid dynamics (CFD) models. The model results were compared with experimental data, and CFD simulation results both with simple geometry to demonstrate validation and assess the performance of the indoor release model. Lastly, the behavior and effect of mitigation of indoor release were demonstrated by using the model results.     

Estimation of safety distances in the vicinity of fuel gas pipelines

In this paper, safety distances around pipelines transmitting liquefied petroleum gas and pressurized natural gas are determined considering the possible outcomes of an accidental event associated with fuel gas release from pressurized transmission systems. Possible outcomes of an accidental fuel gas release were determined by performing the Event Tree Analysis approach. Safety distances were computed for two pipeline transmission systems of pressurized natural gas and liquefied petroleum gas existing in Greece using real data given by Greek Refineries and the Greek Public Gas Enterprise. The software packages chetah and breeze were used for thermochemical mixture properties estimation and quantitative consequence assessment, respectively. Safety distance determination was performed considering jet fire and gas dispersion to the lower flammable limit as the worst-case scenarios corresponding to immediate and delayed cloud ignition. The results showed that the jet fire scenario should be considered as the limiter for safety distances determination in the vicinity of natural and petroleum gas pipelines. Based on this conclusion, the obtained results were further treated to yield functional diagrams for prompt safety distance estimation. In addition, qualitative conclusions were made regarding the effect of atmospheric conditions on possible events. Thus, wind velocity was found to dominate during a jet fire event suppressing the thermal radiation effect, whereas gas dispersion was found to be affected mainly by solar radiation that favors the faster dissolution of fuel gas below the lower flammable limit.     

A dynamic approach for evaluating the consequences of toxic gas dispersion in the chemical plants using CFD and evacuation modelling

Accidental releases of toxic gas in the chemical plants have caused significant harm to the exposed occupants. To evaluate the consequences of these accidents, a dynamic approach considering the gas dispersion and behavior evacuation modelling has been proposed in this paper. This approach is applied to a hypothetical scenario including an accidental chlorine release in a chemical plant. CFD technique is utilized to calculate the time-varying concentration filed and evacuation modelling is used to obtain the evacuation routes. The exposure concentrations in the evacuation routes are calculated by using the code of data query. The integrated concentration toxic load model and probit model are used to calculate the probability of mortality of each occupant by using the exposure concentrations. Based on this dynamic approach, a new concept of average probability of mortality (APM) has been proposed to quantify the consequences of different accidental scenarios. The results show that APM decreases when the required detection time decreases or emergency evacuation mode is implemented. The impact of the detection time on APM becomes small as the wind speed increases. The effect of emergency evacuation mode is more obvious when the release occurs in an outdoor space.     

Simulation of scenario characteristics of LPG tank explosion accident and its contribution to emergency planning: A case study

Leakage and explosion of hazardous chemicals during road transportation can cause serious building damage and casualties, and adoption of highly-efficient emergency rescue measures plays a critical role in reducing accidental hazards. Considering a liquefied petroleum gas (LPG) transport tanker explosion accident that occurred in Wenling, Zhejiang Province, China on June 13, 2020 as example, this study proposes a risk assessment framework. This framework recreates the leakage and explosion of the accident process using FLACS v10.9, suggests plans for evacuation, describes the rescue areas of different levels, and explores the influence of environmental factors on the evacuation and rescue areas. The results show that simulated and predicted distributions of fuel vapour cloud concentration and explosion overpressure can provide a reference basis for rapid rescue activities; the characterization of the dynamic effects of wind speed, wind direction, and temperature with respect to the evacuation and rescue areas can be used as theoretical support for on-site adjustment of rescue forces. The role of obstacles can prevent the expansion of the evacuation areas under low wind-speed conditions, and the presence of highly congested obstacles determines the level of the rescue area. The results obtained are important for the risk analysis and the development of emergency rescue measures in case of explosion accidents associated with transportation of hazardous chemicals on high-hazard and high-sensitive road sections.