HAZOP结合What-if方法在某延迟焦化装置除焦中的应用

为克服传统危险与可操作性（HAZOP）定性分析方法在复杂操作、间歇作业等过程中使用的局限性,提出在传统HAZOP定性分析方法的基础上结合What-if（故障假设）方法,对人的不安全行为和操作规程不完备所导致的风险后果分析作出补充。详细说明其技术原理、工作流程等使用细节,系统阐述该方法与传统HAZOP定性分析方法的区别,并在某延迟焦化装置的除焦操作的风险分析中应用。经分析,识别出在“给水-泡焦”节点,有“操作规程错误”场景2项,“操作规程不具体”场景1项,不存在“操作人员未按操作规程执行”场景。研究结果表明:本文方法有效且具有较好效果,可以广泛应用于操作规程/作业指导书审查、作业过程隐患排查等方面,帮助企业开展操作层面的风险识别与管理,提升企业的生产安全水平。     

Determination of human error probabilities in maintenance procedures of a pump

The “human factor” constitutes an important role in the prediction of safe operation of a facility. Hence, information about human capacities and behaviours should be applied methodically to increase the safety of a systematic process. This paper provides an analysis of human factors in pre- and post-maintenance operations. For possible failure scenarios, this paper considers the procedures for removing process equipment from service (pre-maintenance) and returning the component to service (post-maintenance). In this study, a pump is used as the test example. For each scenario, the human error probability (HEP) is calculated for each activity, using the Human Error Assessment and Reduction Technique (HEART) which is commonly implemented technique in industry, can also be applied in the analyses of safety cases. HEART is a reliable technique for comparing HEP and its approach is based on the degree of error recovery. Consequences are also assessed for each activity in this methodology. The final value of risk for each activity is assigned by combining error likelihood and related consequences. When the calculated risk is beyond acceptable levels, risk management strategies are provided to increase the safety of the maintenance procedures. The most probable human errors for a considered case study are related to the activities of “draining lines” and “open valves”. These two activities have high HEPs, which are 9.57E−01 and 9.62E−01, respectively.     

Assessment of the Consequences of Accident Scenarios Involving Dangerous Substances

This paper highlights major steps in the procedure for evaluating the consequences of accidents involving dangerous substances, especially during the storage, and loading/unloading activities. The procedure relies on identifying accident scenarios that could be encountered at particular plants, followed by a modelling of these scenarios by means of available modelling systems. Finally, the resultant outcomes are identified, together with their effects on both people and property. The resources needed to perform this procedure are discussed, in order to clarify the roles of plant operators, external experts and other institutions when evaluating any accident consequences. Four examples, all relevant in industrial practice, are given in order to illustrate the procedure: the releasing of liquified petroleum gas, flammable organic solvents, toxic chlorine, and oil fuels. The results of these studies may be used for a quick order-of-magnitude estimation of accidents consequences.     

The application of pressure–impulse curves in a blast exceedance analysis

The magnitude of damage due to a vapor cloud explosion can be estimated in many ways, ranging from look-up tables to quantitative risk analysis. An explosion overpressure analysis is a routine part of compliance with the American Petroleum Institute (API) Recommended Practice (RP) 752 when evaluating occupied buildings in a facility that processes flammable or reactive materials. In many cases, a risk-based approach is useful because consequence modeling studies often indicate major problems for buildings at existing facilities. One of the most common risk-based methods, overpressure exceedance, incorporates a wide range of potential explosion scenarios coupled with the probability of each event to develop the probability of exceeding a given overpressure at specific locations. But this and other methods that only use overpressure may not represent an accurate building response. By combining the risk-based methodology of the exceedance analysis with pressure and impulse data in the form of pressure–impulse (P–I) curves, a better measure of building damage can be generated. P–I curves for blast loading determination have been in use for decades, and allow the user to determine levels of damage based on a predicted overpressure and its corresponding impulse. Curves have been published for entire buildings, individual structural members, window breakage, and even consequences to humans. This paper will explore application of P–I curves for building damage, and will highlight some of the benefits, as well as some of the potential problems, of using P–I curves.     

Human error risk analysis in offshore emergencies

Human factors play an important role in the completion of emergency procedures. Human factors analysis is rooted in the concept that humans make errors, and the frequency and consequences of these errors are related to work environment, work culture, and procedures. This can be accounted for in the design of equipment, structures, processes, and procedures. As stress increases, the likelihood of human error also increases. Offshore installations are among the harshest and most stressful work environments in the world. The consequences of human error in an offshore emergency can be severe.A method has been developed to evaluate the risk of human error during offshore emergency musters. Obtaining empirical data was a difficult process, and often little information could be drawn from it. This was especially an issue in determining the consequences of failure to complete muster steps. Based on consequences from past incidents in the offshore industry and probabilities of human error, the level of risk and its tolerability are determined. Using the ARAMIS (accidental risk assessment methodology for industries) approach to safety barrier analysis, a protocol for choosing and evaluating safety measures to reduce and re-assess the risk was developed. The method is assessed using a case study, the Ocean Odyssey incident, to determine its effectiveness. The results of the methodology agree with the analysis of survivor experiences of the Ocean Odyssey incident.     

基于人的认知可靠性(HCR)模型的人因操作失误研究

以人的认知可靠性(HCR)模型为指导,选择包含技能型、规则型和知识型3种认知类型,结合大连化工集团公司影响运行安全的17个异常事件,对54名操纵员的时间响应状况和允许操作时间进行录像、记录与分析;依据IAEA提供的指标[1],找出操纵员在生产过程中可能出现的操作失误类别及其可能造成的危害;基于3参数威布尔模型推导出操纵员操作响应失误概率模型,并从人机工程学角度提出了具体预防事故的安全对策措施。结果表明,基于HCR模型的大化集团公司操纵员的人因操作失误模型实用、有效,为实现操作者与机器系统相协调的目标、正确评估操作着实时操作的响应时间提供了重要参考依据。     

Automation design in advanced control rooms of the modernized nuclear power plants

This study evaluated the effects of levels of automation (LOAs) decisions in advanced control rooms of the modernized nuclear power plants. Following advancements in design of digitalized human–system interfaces (HSIs), the roles of human operators have changed significantly. Negative performance and safety consequences may occur as a result of these changes. These problems are viewed as the out-of-the-loop (OOTL) performance problems. This study conducted an experiment to compare the effects of different LOAs under different operating procedures on operating performance. Experimental results indicated that blended decision-making (level 6 LOA) generates the lowest mental workload. Furthermore, the pattern of SA observed in this study is found better SA at intermediate LOA and poorer SA at low level of automation and full automation. Subjective rating results suggest that LOAs distribute the roles of option generation, and selection between human and/or computer servers which significantly impacts automated system performance. This study provides a direction for the HSI designers in nuclear power plants (NPPs). Additionally, based on results obtained by this study, the user interfaces of PCTRAN system and the alarm reset system should be improved to ensure safe operation of NPPs.     

Application of human factors evaluation in engineering design and safe operation of dense phase ethylene treaters

Ethylene treaters are widely used in the petrochemical industry to remove impurities from ethylene feedstock imported from pipeline networks or storage caverns. The safety concerns of dense phase ethylene treaters due to the reactive and highly flammable nature of ethylene are well known and studied. Under certain conditions, ethylene may self-polymerize and decompose violently with heat release. Under other conditions, ethylene will auto-refrigerate, generating cold liquids that may cause potential brittle fracture hazards. Therefore, dense phase ethylene treaters present design challenges with the unique combination of high temperature decomposition and cold temperature brittle fracture hazards.Due to these safety concerns, it is important to select the appropriate engineering design options for dense phase ethylene treaters and the associated regeneration facilities. Totally automated treater regeneration systems add complexity and instrument maintenance requirements while manually operated systems rely heavily on operator training and procedures. Unfortunately, little or no information or design guidance is available from published research findings in the literature on the evaluation and risk assessment of current industrial design options and practices for dense phase ethylene treaters.This paper presents a systematic risk assessment method to evaluate the engineering design and safe operation options for dense phase ethylene treaters. The proposed risk assessment method integrates human factors task analysis into the traditional HAZOP, LOPA and fault tree analysis to allow evaluation of automated, manual and hybrid approaches with a goal of selecting and optimizing design options to ensure plant safety. This approach provides a realistic assessment of the operational risk and allows identification of fit-for-purpose risk reduction. Applying this systematic risk assessment approach, a simpler and more cost effective design solution can be justified, thereby avoiding the need for a high integrity protective system.     

The role of situation awareness in accidents of large-scale technological systems

In the last two decades, several serious accidents at large-scale technological systems that have had grave consequences, such as that at Bhopal, have primarily been attributed to human error. However, further investigations have revealed that humans are not the primary cause of these accidents, but have inherited the problems and difficulties of working with complex systems created by engineers. The operators have to comprehend malfunctions in real time, respond quickly, and make rapid decisions to return operational units to normal conditions, but under these circumstances, the mental workload of operators rises sharply, and a mental workload that is too high increases the rate of error. Therefore, cognivitive human features such as situation awareness (SA)—one of the most important prerequisite for decision-making—should be considered and analyzed appropriately. This paper applys the SA Error Taxonomy methodology to analyze the role of SA in three different accidents: (1) A runaway chemical reaction at Institute, West Virginia killing two employees, injuring eight people, and requiring the evacuation of more than 40,000 residents adjacent to the facility, (2) The ignition of a vapor cloud at Bellwood, Illinois that killed one person, injured two employees, and caused significant business interruption, and (3) An explosion at Ontario, California injuring four workers and caused extensive damage to the facility. In addition, the paper presents certain requirements for cognitive operator support system development and operator training under abnormal situations to promote operators’ SA in the process industry.     

Consequence modeling of explosion at Azad-Shahr CNG refueling station

Safety of people has been the most important concern since the onset of commercial use of Compressed Natural Gas¹ as a novel type of vehicle fuel. Provided a car vessel bursts, irreversible consequences will surface. The most important hazard threatening people and their properties in CNG distribution stations is pressurized natural gas in station storage vessels and car vessels. Storage vessels are far from people; however, they may damage other properties such as pipes, valves, electrical equipment, and etc. Owing to the distance between storage vessels and the hive, the risk is not considered a big concern; on the contrary, car storage vessel is very close to the passengers sitting in the car and those standing around the car. The proximity heightens the risk as the consequences caused by vessel burst can be more catastrophic than the former condition. Taken together, the car CNG vessel burst may be regarded as the most hazardous event at CNG distribution centers. It is believed that modeling the mentioned events can illustrate risky conditions. The present study was formulated in order to model one of such accidents occurring in Azad-Shahr in the winter 2010. The obtained results provided useful points and recommendations like the minimum safe distance from rupture center depending on such outcomes as overpressure, types of fire, or toxic release. The recommendations provided by the present study can prevent people from calamitous events and they can be adopted so as to reduce severity of possible events.     

基于人差错纠正能力的人因可靠性模型研究

根据人-机系统中人的操作行为具有时序性和差错可纠正性的特点,结合船舶舱室行为形成主因子,开展船舶舱室人因可靠性研究。以人因失误的时序性和差错纠正参数为基础,建立人-机系统中操作者行为模式和人因失误事件树模型。通过对人的差错纠正能力的分析,开展人因可靠性量化模型纠正理论研究。最后,以船舶舱室操作台的监控任务人因可靠性为例进行量化计算,定量评估操作人员执行任务的可靠度。     

Computer simulation of shock waves transmission in obstructed terrains

Generation and transmission of blast waves in real terrains is of major importance for risk analysis procedures involving accidental explosion scenarios. The problem arises from the impact of overpressure wave on people and structures that may be lethal or catastrophic under certain conditions. In this paper, a CFD simulation of shock wave propagation in obstructed terrain is attempted. Overpressure histories as well as a series of critical parameters, namely the positive and negative peak overpressure, the arrival time, and the positive and negative phase duration at specific points within the domain were obtained during the simulation. Their comparison with experimental measurements from field-scale high explosive blast tests performed by HSE showed a reasonably good agreement indicating that CFD computer programs provide reliable tools for estimating explosive shocks in complex terrains.     

基于图形熵的化工应急响应预案复杂度评价

面对突发化工事故,应急处理是控制事故后果、减少损失的有效措施,应急响应预案是应急处理的依据和指南。应急处理中人与系统的交互作用对于事故的缓解或恶化起着至关重要的作用,目前在应急人因失误的研究中纷纷强调操作员操作经验的重要性,而忽略了由于预案逻辑结构过于复杂、可读性太差导致操作员因不能完全理解预案而造成的操作失误,因此讨论了预案复杂度的评价方法。基于图形熵的概念,将文本预案转化为相应的图形,通过计算图形的一、二阶熵确定步骤的5个复杂度因子,进而通过合并步骤复杂度计算任务复杂度。最后,以化工＂切换备用泵＂的应急操作实例对计算方法进行了验证和说明,并针对计算结果给出了减小复杂度的具体措施。实践证明,该方法是有效的。     

Analysis of the boiling liquid expanding vapor explosion (BLEVE) of a liquefied natural gas road tanker: The Zarzalico accident

The road accident of a tanker transporting liquefied natural gas (LNG) originated a fire and, finally, the BLEVE of the tank. This accident has been analyzed, both from the point of view of the emergency management and the explosion and fireball effects. The accidental sequence is described: fire, LNG release, further safety valves release, flames impingement on vessel unprotected wall, vessel failure mode, explosion and fireball. According to the effects and consequences observed, the thermal radiation and overpressure are estimated; a mathematical model is applied to calculate the probable mass contained in the vessel at the moment of the explosion. The peak overpressure predicted from two models is compared with the values inferred from the accident observed data. The emergency management is commented.     

Evaluation of the Risk OMT model for maintenance work on major offshore process equipment

Operational safety is receiving more and more attention in the Norwegian offshore industry. Almost two thirds of all leaks on offshore installations in the period 2001–2005, according to the Risk Level Project by the Petroleum Safety Authority in Norway, resulted from manual operations and interventions, as well as shut-down and start-up. The intention with the Risk OMT (risk modelling – integration of organisational, human and technical factors) program has been to develop more representative models for calculation of leak frequencies as a function of the volume of manual operations and interventions. In the Risk OMT project a generic risk model has been developed and is adapted to use for specific failure scenarios. The model considers the operational barriers in event trees and fault trees, as well as risk influencing factors that determine the basic event probabilities in the fault trees. The full model, which applies Bayesian belief networks, is presented more thoroughly in a separate paper. This paper presents the evaluation of the model. The model has been evaluated through some case studies, and one important aspect is the evaluation of the importance of each risk influencing factor. In addition some risk-reducing measures have been proposed, and the paper presents how the effect of these measures has been evaluated by using the model. Finally, possible applications and recommendations for further work are discussed.     

基于视线追踪技术的工艺操作人员人为失误识别研究

为了对生产加工过程中工艺操作人员的不安全行为进行有效监控，及时避免因操作失误带来的工艺安全事故，开展基于视线追踪技术的工艺操作人员人为失误识别研究。通过设计眼动实验方案，利用视线追踪技术采集操作者在工艺流程控制过程中各类失误模式的眼动数据,并对采集的数据进行统计，提取失误行为的眼动特征，并建立人为失误智能识别方法，利用距离函数聚类实现现场操作人员失误状态的准确识别。研究结果表明:以被试样本在不同区域的视线停留时间百分比作为特征参数，并运用欧氏距离函数分类法判别人员操作状态，对操作人员的不安全行为能够准确识别。     

Modelling the mitigation of a hydrogen deflagration in a nuclear waste silo ullage with water fog

During the decommissioning of certain legacy nuclear waste storage plants it is possible that significant releases of hydrogen gas could occur. Such an event could result in the formation of a flammable mixture within the silo ullage and, hence, the potential risk of ignition and deflagration occurring, threatening the structural integrity of the silo. Very fine water mist fogs have been suggested as a possible method of mitigating the overpressure rise, should a hydrogen–air deflagration occur. In the work presented here, the FLACS CFD code has been used to predict the potential explosion overpressure reduction that might be achieved using water fog mitigation for a range of scenarios where a hydrogen–air mixture, of a pre-specified concentration (containing 800 L of hydrogen), uniformly fills a volume located in a model silo ullage space, and is ignited giving rise to a vented deflagration. The simulation results suggest that water fog could significantly reduce the peak explosion overpressure, in a silo ullage, for lower concentration hydrogen–air mixtures up to 20%, but would require very high fog densities to be achieved to mitigate 30% hydrogen–air mixtures.     

Machine learning based quantitative consequence prediction models for toxic dispersion casualty

Incidental release of toxic chemicals can pose extreme danger to life in the vicinity. Therefore, it is crucial for emergency responders, plant operators, and safety professionals to have a fast and accurate prediction to evaluate possible toxic dispersion life-threatening consequences. In this work, a toxic chemical dispersion casualty database that contains 450 leak scenarios of 18 toxic chemicals is constructed to develop a machine learning based quantitative property-consequence relationship (QPCR) model to estimate the affected area caused by toxic chemical release within a certain death rate. The results show that the developed QPCR model can predict the toxic dispersion casualty range with root mean square error of maximum distance, minimum distance, and maximum width less than 0.2, 0.4, and 0.3, which indicates that the constructed model has satisfying accuracy in predicting toxic dispersion ranges under different lethal consequences. The model can be further expanded to accommodate more toxic chemicals and leaking scenarios.     

Automated diagnosis of malfunctions based on object orientated programming

The diagnostic event analyser (DEA) is a system for automated diagnosis of malfunction in continuous processes. DEA interprets real-time sequences of abnormal events such as measurements out of normal ranges and violation of quantitative algebraic constraints. DEA can be used to supplement an existing alarm system, providing a higher-level interpretation of patterns of abnormal events for the process operator. To use DEA, the user must supply only standard ‘form’ inputs of the root causes and relationships between abnormal events. DEA is implemented using object- oriented programming, a technique which allows general rules and procedures to be applied to process-specific objects. This architecture facilities treatment of multiple malfunctions and robustness to variation in event sequences.     

NIOSH手工提举方程在缸盖搬运中的应用

为了平衡操作人员的精力和体力,在保证人安全的前提下,提高生产力。采用NIOSH（National Institute of Occupational Safety and Health）提举方程对机加工车间缸盖搬运上线工位进行人机工程安全评估,通过对操作工作业的水平距离（H）、垂直距离（V）、提升距离（D）以及频率（F）进行研究,并对修订版NIOSH提举方程的重量常量与高度系数进行了修正。结果表明,经过合理调整四大参数,可在不设起吊、机器人等设备的情况下,保证人的身心健康,节约成本,提高人的工作效能。