Comparison of inherent safety indices in process concept evaluation

In conceptual design, process routes can be compared and ranked by using inherent safety indices. In this paper, some inherent safety index methods presented in literature are compared and their properties and limitations discussed. As a case study, an inherent safety evaluation of methyl methacrylate process routes is presented. Three index based inherent safety evaluation methods are compared with expert evaluations on methyl methacrylate process routes and their subprocesses. Also the index based inherent safety ranking of process routes is compared with an expert ranking.     

基于本质安全的化工工艺物质危险指数研究

建立了基于本质安全的化工工艺物质危险性的评价体系,包括火灾危险性、爆炸危险性以及毒性等3个评价指数.基于风险的思想,各个评价指数均包括概率指标与后果指标.为了全面反映化工工艺的实际情况,在各个评价指数中均对所有物质的相应指数值加和.参数的取值以以往的指数法为基础,为了消除边界波动效应,取值采用内插法.由于各个指数的量纲...     

危险品道路运输风险分级指数法研究

危险品道路运输过程风险影响因素多,随机性和不确定性大,定量风险评价比较复杂,至今没有统一的风险评估模型.为了有效预防危险品运输事故和进行快速风险评估,基于运输危险品本身特性和相关的风险影响因素探讨了运输危险品现实风险分级指数法.该方法由危险品风险分级指数、路线影响因素和安全措施补偿因子3部分构成.危险品风险分级指数由危险品加权平均风险等级和运输危险品量、泄漏点与居民区距离以及危险品扩散因子等级确定.危险品加权平均风险等级涉及其健康危害性、可燃性、化学反应活性以及特殊危险性(氧化性和与水反应性)等级的确定.路线影响因素包含运输道路特征、气象条件、交通状况和影响人员分布4类.安全措施补偿因子为车辆、设备、容器、包装因子,人员素质因子和安全管理因子3类.该方法可对运输危险品的潜在风险进行快速分级,有利于采取有效的安全预防和控制措施,降低运输事故概率和沿线影响人员风险.     

Using process stream index (PSI) to assess inherent safety level during preliminary design stage

In the current practice, safety assessment is conducted once the process design has been completed. At this stage of design, the freedom to change the conceptual design is very limited and whatever strategies to be implemented will only control the hazard. This paper reports on the development of inherent safety index known as a process stream index (PSI) for inherent safety level assessment at preliminary design stage from the perspective of an explosion. The aim for PSI is to calculate, compare and prioritize the level of inherent safety of process streams during simulation work that influences the explosion. By prioritizing the streams based on the potential for the explosion, the design engineers can easily identify the critical streams to be considered for improvement in order to avoid or minimize explosion hazards. An enhancement technique to reflect the contribution of the individual components in the mixture is introduced, which provide significant contribution to the ranking of inherent safety level of process streams. The assessment of inherent safety level using PSI is demonstrated by case studies of HYSYS simulation for Acrylic Acid Plant and Natural Gas Liquid (NGL) plant.     

Inherent safety in offshore oil and gas activities: a review of the present status and future directions

Inherent safety is a proactive approach for hazard/risk management during process plant design and operation. It has been proven that, considering the lifetime costs of a process and its operation, an inherently safer approach is a cost-optimal option. Inherent safety can be incorporated at any stage of design and operation; however, its application at the earliest possible stages of process design (such as process selection and conceptual design) yields the best results.Although it is an attractive and cost-effective approach to hazard/risk management, inherent safety has not been used as widely as other techniques such as HAZOP and quantitative risk assessment. There are many reasons responsible for this; key among them are a lack of awareness and the non-availability of a systematic methodology and tools.The inherent safety approach is the best option for hazard/risk management in offshore oil and gas activities. In the past, it has been applied to several aspects of offshore process design and operation. However, its use is still limited. This article attempts to present a complete picture of inherent safety application in offshore oil and gas activities. It discuses the use of available technology for implementation of inherent safety principles in various offshore activities, both current and planned for the future.     

A novel chemical product design framework with the integration of safety and health aspects

Computer-aided molecular design (CAMD) technique is a powerful tool for the design of molecules that meet a set of desirable properties. In most of the CAMD problems, the molecular physical and thermodynamic properties are often selected as the target properties, while safety and health aspects were not taken into consideration. However, certain chemical substances may cause adverse effects to human's health after prolonged and repeated exposure. Therefore, in order to ensure that the generated molecule does not bring harm and health-related risks to the consumers, it is crucial to incorporate both inherent safety and health into the existing CAMD techniques. In this work, a novel chemical product design methodology has been developed to integrate both safety and health aspects into the CAMD framework presented by a single optimisation model. The measurement of safety and health indicators are based on the molecular properties that have impact on both of these aspects. Each property is assigned with an index or penalty value based on the degree of potential hazards. A molecule with a higher index value has a higher hazard level and vice versa. Hence, a molecule that satisfies the target properties and has a low penalty value will be selected as the most reasonable choice. This new approach ensures that a product that possesses the desirable properties, and at the same time meets the safety and health criteria, is produced. A case study on the solvent design for gas sweetening process has been carried out to determine the optimal molecule.     

Implementing inherent safety throughout process lifecycle

Inherent safety should be implemented as early as possible in the design life cycle, since the changes in process design are easier and cheaper the earlier they are done. The problem is, how to evaluate process alternatives in the terms of inherent safety in the early design phases, when much of the information is missing. In this paper the process life cycle phases and the possibilities of implementing and evaluating inherent safety are discussed. The applicability and accuracy of an inherent safety index method is presented by a case study.     

基于本质安全的化学工艺风险评价方法研究

基于本质安全原理对化学工艺进行风险评价,以易燃性、易爆性、毒性、腐蚀性、反应热、化学活性、工艺温度、工艺压力和存储量9个指标,建立化学工艺的本质安全评价指标体系。采用基于遗传算法的Shepard插值算法对本质安全进行评价,以甲基丙烯酸甲酯的合成工艺路线为例进行分析,结果表明该方法适用于化学工艺本质安全评价,相对传统方法更加科学,能够有效对危险工艺进行选择,为政府监管部门和化工企业提供工艺选择决策技术。     

Qualitative Assessment for Inherently Safer Design (QAISD) at preliminary design stage

Conventional hazard evaluation techniques such as what-if checklist and hazard and operability (HAZOP) studies are often used to recognise potential hazards and recommend possible solutions. They are used to reduce any potential incidents in the process plant to as low as reasonably practicable (ALARP) level. Nevertheless, the suggested risk reduction alternatives merely focus on added passive and active safety systems rather than preventing or minimising the inherent hazards at source through application of inherently safer design (ISD) concept. One of the attributed reasons could be the shortage of techniques or tools to support implementation of the concept. Thus, this paper proposes a qualitative methodology that integrates ISD concept with hazard review technique to identify inherent hazards and generate ISD options at early stage of design as proactive measures to produce inherently safer plant. A modified theory of inventive problem solving (TRIZ) hazard review method is used in this work to identify inherent hazards, whereby an extended inherent safety heuristics tool is developed based on established ISD principles to create potential ISD options. The developed method namely Qualitative Assessment for Inherently Safer Design (QAISD) could be applied during preliminary design stage and the information required to apply the method would be based on common process and safety database of the studied process. However, user experiences and understanding of inherent safety concept are crucial for effective utilisation of the QAISD. This qualitative methodology is applied to a typical batch reactor of toluene nitration as a case study. The results show several ISD strategies that could be considered at early stage of design in order to prevent and minimise the potential of thermal runaway in the nitration process.     

基于模糊综合评价的化工工艺本质安全指数研究

建立化工工艺的本质安全评价指标体系,包括可燃性、爆炸性、毒性、反应性、温度、压力、储量等7个指标。为解决前人指数法中的边界波动效应,采用模糊综合评价建立化工工艺本质安全评价指数模型,确定各指标的权重、危险分级及对各分级的隶属函数。以甲基丙烯酸甲酯的5条工艺路线为例进行分析,结论与前人提出的指数方法的评价结果相吻合,表明该指数方法可以用来进行化工工艺的本质安全评价,以指导设计初期的本质安全型工艺路线选择。     

Developments in inherent safety: A review of the progress during 2001–2011 and opportunities ahead

This paper reviews the progress in inherent safety. A summary of the historical developments up to the year 2000 is first presented which sets the stage for a review of the key developments during the first 11 years of the 21st century. A landscape of inherent safety is developed by mapping publications on two coordinates. The first coordinate, the risk coordinate, indicates if the focus of a paper relates to inherent hazard or to the likelihood of events. The second coordinate, the management coordinate, focuses on the ways and means to understand and assess inherent safety. Out of the 187 papers that have appeared over this 11-year period, 131 pertained to developments in inherently safer design; these have been organized on the proposed landscape. The rest introduce the basic concepts of inherent safety and address its incorporation into regulation, education and accident investigation. These along with the application of inherent safety in industry are also discussed. We conclude with a discussion on recent trends in industry and suggest directions for future research.     

Systematic incorporation of inherent safety in hazardous chemicals supply chain optimization

Increasing globalization has made many chemical supply chains large, interdependent and complex. Process incidents often affect the reliability of a supply chain and can cause large disruptions at different segments of the industry. We propose an optimization-based framework that systematically takes into account the trade-offs between process safety and supply chain economics for decision-making. We quantify the hazard at various supply chain echelons in the form of a safety index that takes both fire and toxic hazards into account. A mixed-integer nonlinear programming (MINLP)-based model is developed to either maximize profit for specified hazard limits, or to minimize hazard in a supply chain with multiple production plants, technological options, warehouses and distribution nodes. The MINLP model is used to generate trade-off optimal solutions for various toxic and fire hazard limits. The framework is demonstrated by applying it to an end-to-end ammonia supply chain case study which resulted in several non-intuitive observations regarding hazardous supply chain design and optimization.     

关于企业安全评价的探讨

本文以国内企业安全评价发展现状的调查研究为基础,提出了企业安全评价的基本结构和基本方法。分别论述了企业固有危险性评价、企业安全管理现状评价和企业现实危险性评价的定义、评价范围和内客、评价方法,以及评价的目的与作用。在此基础上探讨建立三者的相互关系和企业安全评价的总体设想。     

Economic assessment of inherently safe membrane reactor technology options integrated into IGCC power plants

Pd/alloy-based (Pd/Cu, Pd/Au) membrane reactors embedded into Integrated Gasification Combined Cycle (IGCC) plants (IGCC-MR) enable the storage and/or use of the energy value of H₂ to produce electricity while the CO₂ enriched retentate exit stream becomes particularly suitable for high pressure CO₂ capture-sequestration. There is undoubtedly a lack of operating experience associated with IGCC-MR plants, and therefore, sound process intensification principles/practices should be followed not only to enhance process system performance but also to ensure process safety and economic feasibility of an IGCC-MR plant. Motivated by the above considerations, a comprehensive process economic assessment framework for an inherently safe membrane Pd/alloy-based reactor integrated into an IGCC plant is proposed. In particular, a detailed Net Present Value (NPV) model has been developed to evaluate the economic viability of an IGCC-MR plant where the membrane reactor module design conforms to basic inherent safety principles. Sources of irreducible uncertainty (market, regulatory and technological) are explicitly recognized such as the power plant capacity factor, Pd price, membrane life time and CO₂-taxes due to future regulatory action/policies. The effect of the above uncertainty drivers on the project's/plant's value is studied through Monte Carlo methods resulting in detailed NPV-distribution and process economic outcome profiles. The simulation results derived suggest that in the presence of (operational, economic and regulatory) uncertainties, inherently safe membrane reactor technology options integrated into IGCC plants could become economically viable. In particular, comparatively more attractive NPV distribution profiles are obtained when concrete safety risk-reducing measures are taken into account through pre-investment in process safety (equipment).     

白酒厂类火灾高危单位消防安全评估及应用

白酒厂属于典型的甲乙类火灾高危单位,具有火灾风险高、火灾扑救难度大、火灾造成伤亡大等特点。以白酒厂类火灾高危单位为研究对象,针对酒厂酒库、原酒车间、成品库、包装车间、包装材料库、办公楼等重点部位,通过深入调研,采用安全检查表法分析某白酒厂存在的火灾安全隐患及安全管理的薄弱环节,用层次分析法建立了该白酒厂的消防安全评估指标体系,主要包括建筑火灾风险、消防救援力量和消防给水几个方面。采用专家打分法赋予评估指标权重,并根据风险等级划分得出该酒厂的整体火灾风险评估等级,进而评判该酒厂的安全状况,针对存在的火灾隐患及薄弱环节采取有针对性的预防措施和有重点的整改管理,保障其安全生产。     

A quantitative risk management framework for dust and hybrid mixture explosions

Dust and hybrid-mixture explosions continue to occur in industrial processes that handle fine powders and flammable gases. Considerable research is therefore conducted throughout the world with the objective of both preventing the occurrence and mitigating the consequences of such events. In the current work, research has been undertaken to help move the field of dust explosion prevention and mitigation from its current emphasis on hazards (with an accompanying reliance on primarily engineered safety features) to a focus on risk (with an accompanying reliance on hierarchical, risk-based, decision-making tools). Employing the principles of quantitative risk assessment (QRA) of dust and hybrid-mixture explosions, a methodological framework for the management of these risks has been developed.The QRA framework is based on hazard identification via credible accident scenarios for dust explosions, followed by probabilistic fault-tree analysis (using Relex – Reliability Excellence – software) and consequence severity analysis (using DESC – Dust Explosion Simulation Code – software). Identification of risk reduction measures in the framework is accomplished in a hierarchical manner by considering inherent safety measures, passive and active engineered devices, and procedural measures (in that order). An industrial case study is presented to show how inherent safety measures such as dust minimization and dust/process moderation can be helpful in reducing dust and hybrid-mixture explosion consequences in a 400-m³ polyethylene storage silo.     

海洋钻井平台事故致因分析与评价指标研究

该文在广泛调研国内外已发生的海洋平台事故基础上,从人因失误、工艺设备、物料危险、管理缺陷和危险环境五个方面系统分析事故致因因素,提出海洋钻井平台事故致因评价框架,提出5个一级评价指标和24个二级评价指标,根据层次分析法,计算确定各指标的标准权重值.最后针对某在役海洋钻井平台,开展实例研究.为实际评价海洋钻井平台事故风险提供一种新方法,具有一定的实际应用价值.     

基于地震动参数的大型储罐潜在危险性评估方法研究

建设项目安全条件分析中有关自然条件影响分析内容通常采取定性方法加以研究。以地震对大型储罐造成的潜在危险性评估为研究对象,从地震动作用下储罐结构动力响应及破坏特征入手,详细介绍了美国联邦应急管理署(FEMA)开发的HAZUS-MH中的震害危险评估框架及理论模型。重点阐述了地震反应谱、承灾体脆弱性曲线、能力曲线以及需求曲线在危险性评估过程的应用及参数设定。以某大型低温液化气储罐为例,定量计算了地震潜在破坏程度及概率,借此说明该震害危险性评估框架和方法对我国安全评价工作的借鉴意义。     

基于模糊模式识别的模糊综合评价在高层建筑火灾危险评价中的应用

针对高层建筑火灾危险的特点,建立了高层建筑火灾危险评价的指标体系,并应用层次分析法确定了其权重。根据高层建筑火灾危险评价系统具有多因素、多层次的特点,采用模糊综合评价方法;针对模糊综合评价的不足之处,提出把权广义距离之和最小模糊模式识别运用到模糊综合评价当中,建立了基于模糊模式识别的模糊综合评价模型;该评价模型避免了单因素矩阵的确定和模糊算子的选择问题,用安全状态特征值来表征最终的评价结果,能使评价结果更加准确,可操作性强。通过对陕西某高层建筑火灾危险评价实例证明,该模型具有较好的应用价值,为日常的安全管理和性能化防火设计提供了有用依据。     

Model-based HAZOP study of a real MTBE plant

Integration of a mathematical model approach with hazard and operability (HAZOP) analysis is presented in this contribution. The presented analysis is based on the mathematical modelling of a process unit, where both the steady-state analysis (including continuation and bifurcation analyses), and the dynamic simulation are used. The main benefit of this integration is the ability to perform a detail safety analysis for a relatively complicated process. Such an approach may dramatically decrease the possibility that several sources of hazard will be overlooked. Of course, the presented methodology may also seriously reduce the time necessary for the hazard identification process. In this paper, a methyl tertiary-butyl ether (MTBE) production unit was chosen to identify potential hazard and operational problems of a real process. This simplified case-study unit consists of two investigated types of equipment: a tubular fixed bed reactor and a reactive distillation column.