A structural approach to the HAZOP – Hazard and operability technique in the biopharmaceutical industry

Recently, the use of analytical techniques to identify, assess and address risks within the pharmaceutical industry is increasing from the initial and operating phases until the final use of products aiming to eliminate or reduce the severity of deviations. The hazard and operability studies – HAZOP establish that accidents are the result of failure modes in process variables out of operational parameters. In this paper, the HAZOP methodology was used to assess risks in the system for recombinant protein production where a multidisciplinary group used the brainstorming strategy to identify the risk level and deviations in nodes defined by functionality in the system. Nineteen critical nodes were identified, deviations were established in based on knowledge, and experience by the group, thus precluded the need of deviation's records to estimate frequency and impacts of events. It was also shown that in the pharmaceutical industry the most-critical risks are those that have adverse impacts on production like partial and total losses and when noncompliance of regulations are involved. The HAZOP risk assessment tool can be easily followed by people who are interested in starting to use this technique to improve the security environment within the institution and when required by regulatory agencies.     

The integration of HAZOP expert system and piping and instrumentation diagrams

The main purpose of hazard and operability (HAZOP) analysis is to identify the potential hazards in the process design which nowadays is generally developed through a computer aided design (CAD) package. Due to the time and effort consuming nature of HAZOP, it is not done in every engineering firm for every design project. To make HAZOP an integral part of process design, an integration framework is proposed in this paper to seamlessly integrate the commercial process design package Smart Plant P&ID (SPPID, Intergraph) with one of the HAZOP expert systems (named as LDGHAZOP) developed by authors. This integration makes it possible to perform HAZOP analysis easily at anytime of the whole lifecycle of a chemical plant as long as the process design is available, which might help the improvement of design quality. One industrial case study is used to illustrate the ability of the integrated system.     

Ontology-based computer aid for the automation of HAZOP studies

Hazard and Operability (HAZOP) studies are conducted to identify and assess potential hazards which originate from processes, equipment, and process plants. These studies are human-centered processes that are time and labor-intensive. Also, extensive expertise and experience in the field of process safety engineering are required. There have been several attempts by different research groups to (semi-)automate HAZOP studies in the past. Within this research, a knowledge-based framework for the automatic generation of HAZOP worksheets was developed. Compared to other approaches, the focus is on representing semantic relationships between HAZOP relevant concepts under consideration of the degree of abstraction. In the course of this, expert knowledge from the process and plant safety (PPS) domain is embedded within the ontological model. Based on that, a reasoning algorithm based on semantic reasoners is developed to identify hazards and operability issues in a HAZOP similar manner. An advantage of the proposed method is that by modeling causal relationships between HAZOP concepts, automatically generated but meaningless scenarios can be avoided. The results of the enhanced causation model are high quality extended HAZOP worksheets. The developed methodology is applied within a case study that involves a hexane storage tank. The quality and quantity of the automatically generated results agree with the original worksheets. Thus the ontology-based reasoning algorithm is well-suited to identify hazardous scenarios and operability issues. Node-based analyses involving multiple process units can also be carried out by a slight adjustment of the method. The presented method can help to support HAZOP study participants and non-experts in conducting HAZOP studies.     

HAZOP方法的定量改进措施研究

HAZOP方法通过结构化和系统化的方式识别潜在的危险与可操作性问题,在化工安全评价中得到了广泛应用.但其做为一种定性评价方法,定量化是其发展的趋势.探讨了定量化风险矩阵技术在HAZOP分析中应用的问题,研究提出了将火灾、爆炸危险指数方法应用于风险矩阵事故后果严重度的计算和将事故树评价方法应用于风险矩阵事故发生概率的计算,实现了风险矩阵的定量化并应用于不饱和聚酯树脂工艺HAZOP分析,为HAZOP分析的定量化提供了一种新的技术方法.     

基于三角模糊数的HAZOP分析在石油化工装置中的应用

工艺危害分析强调运用系统的方法对危害进行辨识、分析,并采取必要的措施消除和减少危害。HAZOP分析能对工艺过程非常系统、全面的进行分析,但传统的HAZOP分析在量化风险时,对于偏差原因发生的可能性评价存在较大的主观性。本文对于没有统计资料的HAZOP分析偏差原因发生可能性,采用专家打分法,利用三角模糊数来表示其模糊发生概率。对于有统计资料的偏差原因,直接表示成三角模糊数。这种方法能够很好的表示HAZOP分析偏差发生概率。介绍了基于三角模糊数的HAZOP分析步骤,并在石油化工装置中进行了应用。这对HAZOP分析技术在石油化工装置中的推广具有重要意义。     

工艺过程危险有害因素辨识的研究

鉴于化工企业工艺过程的特殊性,笔者建议其危险、有害因素的辨识可以在直观经验分析法和系统安全分析法的基础上,结合危险和可操作性研究(HAZOP)的思想来进行辨识。笔者尝试性地给出了相关术语的说明、介绍辨识方法和操作程序,并分别从生产过程(包括化学反应、化工操作单元和物料输送)和工艺设备、装置角度,对其中的所包含的具体内容进行剖析,最后以电解过程举例说明,该方法可用于化工企业进行危险性因素辨识。     

An extended HAZOP analysis approach with dynamic fault tree

An extended hazard and operability (HAZOP) analysis approach with dynamic fault tree is proposed to identify potential hazards in chemical plants. First, the conventional HAZOP analysis is used to identify the possible fault causes and consequences of abnormal conditions, which are called deviations. Based on HAZOP analysis results, hazard scenario models are built to explicitly represent the propagation pathway of faults. With the quantitative analysis requirements of HAZOP analysis and the time-dependent behavior of real failure events considered, the dynamic fault tree (DFT) analysis approach is then introduced to extend HAZOP analysis. To simplify the quantitative calculation, the DFT model is solved with modularization approach in which a binary decision diagram (BDD) and Markov chain approach are applied to solve static and dynamic subtrees, respectively. Subsequently, the occurrence probability of the top event and the probability importance of each basic event with respect to the top event are determined. Finally, a case study is performed to verify the effectiveness of the approach. Results indicate that compared with the conventional HAZOP approach, the proposed approach does not only identify effectively possible fault root causes but also quantitatively determines occurrence probability of the top event and the most likely fault causes. The approach can provide a reliable basis to improve process safety.     

Process hazards review applied to the use of anhydrous ammonia in agriculture: an example of chemical process safety for small business

Process hazards review (PHR) techniques have generally been applied by large, sophisticated companies in the nuclear, aerospace, and chemical process industries. There remains, however, a large population of smaller distributors and consumers of hazardous materials which could benefit equally from the application of PHR. These consumers unfortunately are generally less sophisticated and individually lack the necessary resources required to apply such state-of-the-art safety techniques.

Where common processes can be identified, it is possible to conduct a more generic PHR that will provide a sound technical basis for recognizing and preventing the development of hazards wherever these processes are used. Some facility-specific issues will always need to be considered, but the existence of the generic PHR should make the conduct of a PHR by each facility considerably easier and less costly.

Researchers from the National Institute for Occupational Safety and Health (NIOSH) contracted with DNV Technica Inc. to lead a hazard and operability study (HAZOP) of agricultural handling of anhydrous ammonia, from the receipt of ammonia at the retail distribution centre to the application of the ammonia by farmers to the fields. The multidisciplinary HAZOP team consisted of representatives from NIOSH, an agricultural chemical trade association, an ammonia producer, state ammonia facility inspectors, a retail distributor, and an equipment manufacturer. Several participants were part-time farmers with ammonia application experience.

Some specific aspects of applying the HAZOP technique in the context of this study, the findings obtained, and the plans to disseminate the important safety information developed during the course of the PHR are discussed. Finally, it is suggested that this approach could prove to be a useful addition to the product stewardship activities of chemical producers.     

State of research on the automation of HAZOP studies

For more than 30 years, multiple research groups have worked on the automation of hazard and operability (HAZOP) studies, or more specifically on the hazard identification process. So far, very few of these approaches have been used in the chemical process industry. Automatic hazard identification is a knowledge-intensive process that demands high standards with regard to the way in which knowledge is stored and made available. There are various suitable approaches to the qualitative modeling of processes and plants, which are the foundation for reasoning systems that are used for the identification of hazards. Additionally, there are quantitative methods that are based on process simulations and can be used to identify potential hazards. The investigation of the state of research demonstrates that there are sophisticated technologies for automated systems that include powerful reasoning techniques. The benefits and shortcomings of existing technologies are discussed with regard to their industrial applicability. Often, the quality of the necessary specific and generic knowledge is not sufficient to detect potential hazardous events and operational malfunctions. Computer-aided HAZOP systems should be integrated with computer-aided design- or process simulation software using common data models based on the digital representation of the process plant. In order to be used by HAZOP practitioners automated systems need to be comprehensive, serve as specialized decision support systems, and be tested and evaluated using round robin tests.     

在役柴油加氢装置HAZOP分析技术

柴油加氢装置属甲类火灾危险生产装置,为了保障其安全生产,实现事故早期预防,对其进行风险分析和安全评价势在必行.HAZOP分析方法是流程工业广泛使用的一种危险辨识和分析方法,具有较好的系统性和完备性.首先介绍了HAZOP分析方法的由来及应用情况,其次分析了在役装置HAZOP分析的难点,并提出了相应的建议,然后详述了在役装置HAZOP方法的分析流程.最后以中石油某石化公司在役柴油加氢装置为例进行了HAZOP分析,辨识出可能存在的安全隐患和潜在危险,对较高风险提出了必要的安全保护措施和合理的改进建议.结果表明,HAZOP分析是提高在役装置安全性的一种有效手段,其结果为装置安全管理提供了可靠的依据.     

Application of risk analysis in the liquefied natural gas (LNG) sector: An overview

In recent years, the global demand for liquefied natural gas (LNG) as an energy source is increasing at a very fast rate. In order to meet this demand, a large number of facilities such as platforms, FPSO (floating production, storage and offloading), FSRU (floating storage and regasification unit) and LNG ships and terminals are required for the storage, processing and transportation of LNG. Failure of any of these facilities may expose the market, companies, personnel and the environment to hazards, hence making the application of risk analysis to the LNG sector a very topical issue throughout the world. To assess the risk of accidents associated with LNG facilities and carriers, various risk analysis approaches have been employed to identify the potential hazards, calculate the probability of accidents, as well as assessing the severity of consequences. Nonetheless, literature on classification of the risk analysis models applied to LNG facilities is very limited. Therefore, to reveal the holistic issues and future perspectives on risk analysis of LNG facilities, a systematic review of the current state-of-the-art research on LNG risk analysis is necessary. The aim of this paper is to review and categorize the published literature about the problems associated with risk analysis of LNG facilities, so as to improve the understanding of stakeholders (researchers, regulators, and practitioners). To achieve this aim, scholarly articles on LNG risk analysis are identified, reviewed, and then categorized according to risk assessment methods (qualitative, semi-qualitative or quantitative; deterministic or probabilistic; conventional or dynamic), tools (ETA, FTA, FMEA/FMECA, Bayesian network), output/strategy (RBI, RBM, RBIM, facility siting, etc.), data sources (OREDA handbook, published literature, UK HSE databases, regulatory agencies' reports, industry datasets, and experts’ consultations), applications (LNG carriers and LNG fuelled ships, LNG terminals and stations, LNG offshore floating units, LNG plants), etc. Our study will not only be useful to researchers engaged in these areas but will also assist regulators, policy makers, and operators of LNG facilities to find the risk analysis models that fit their specific requirements.     

Integration of process control protection layer into a simulation-based HAZOP tool

This paper discusses the framework methodology behind the proposed simulation-based HAZOP tool. Simulation-based approach is one of the many ways to support conventional HAZOP by its automation. Compared to knowledge-based and other approaches, a HAZOP software tool based on deviations simulation is able to examine the investigated process more into detail and so find root causes of hazardous consequences. Another advantage is the ability to identify also potential hazards which did not occur in the past and might be overlooked. The presented framework methodology uses a layer of protection analysis (LOPA) concept of independent protection layers (IPLs) testing. Control system integrated into the raw process design represents the first of various protection layers of the LOPA concept. As a case study, a CSTR chemical production with nonlinear behavior under Proportional-Integral-Derivative (PID) actions as the predominant type of classical feedback control strategy is used. The presented tool identifies hazardous regimes under conditions when control loop introduces hazardous consequences or even acts synergically with existing hazardous events. Risk derived from different consequences is ranked by the risk assessment matrix (RAM) as a part of the conventional quantitative HAZOP study.     

HAZOP技术在炼油火炬系统工艺危害分析中的应用

为系统辨识火炬系统存在的危险有害因素,提高火炬系统的安全设计及运行水平,采用危险与可操作性（HAZOP）分析对火炬系统开展了工艺危害分析。以火炬筒体为例,分析了火炬筒体的控制参数,给出了筒体火焰小、高空点火器点火不成功、地面爆燃点火系统点火失败等偏差的HAZOP分析结果,并针对高风险的偏差提出了相应的建议措施。从分析效果来看,HAZOP技术可用于炼油火炬系统的工艺危害分析,能系统地辨识炼油火炬系统存在的隐患,有助于提高装置工艺安全水平。     

TOPHAZOP: a knowledge-based software tool for conducting HAZOP in a rapid, efficient yet inexpensive manner

Hazard and operability (HAZOP) studies constitute an essential step in the risk analysis of any chemical process industry and involve systematic identification of every conceivable abnormal process deviation, its causes and abnormal consequences. These authors have recently proposed optHAZOP as an alternative procedure for conducting HAZOP studies in a shorter span of time than taken by conventional HAZOP procedure, with greater accuracy and effectiveness [Khan, F. I. and Abassi, S. A., optHAZOP. An effective and efficient technique for hazard identification and assessment Journal of Loss Prevention in the Process Industries, 1997, 10, 191–204]. optHAZOP consists of several steps, the most crucial one requires use of a knowledge-based software tool which would significantly reduce the requirement of expert man-hours and speed up the work of the study team. TOPHAZOP (Tool for OPTmizing HAZOP) has been developed to fulfil this need.

The TOPHAZOP knowledge-base consists of two main branches: process-specific and general. The TOPHAZOP framework allows these two branches to interact during the analysis to address the process-specific aspects of HAZOP analysis while maintaining the generality of the system. The system is open-ended and modular in structure to make easy implementation and/or expansion of knowledge. The important features of TOPHAZOP and its performance on an industrial case study are described.     

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.     

HAZID方法浅析

结合实际工程建设项目开展危险源辨识（HAZID）分析的情况,介绍了HAZID分析方法的广义和狭义概念内涵,主要分析步骤、每步主要工作内容、典型引导词、分析形式和特点,并将HA-ZID方法与常用的过程危险源方法、尤其是HAZOP分析方法进行了对比,以帮助读者更好地理解、运用此方法。本文拟推荐的HAZID分析方法将危险化学品行业的风险管理向前延伸到项目的早期阶段（如项目论证、可行性研究、基础工程设计或初步设计阶段）,可以帮助项目组在项目建设早期认识与项目有关的健康、安全、环境（HSE）各方面问题的重要性和相关性,所辨识出的关键危险源及其危险,为下一步有重点、有目的地开展项目HSE风险管理确定了关注重点。在早期阶段进行HAZID分析,还可以有机会以最小的代价实现对项目厂址和总图布置的调整、工艺方案和设计原则的优化,可以避免后期再发现HSE隐患、必须整改时可能存在的不可实施性,或对项目费用、进度等产生严重负面影响。     

Using a system theory based method (STAMP) for hazard analysis in process industry

Different hazard analysis techniques are used in the chemical process industry. Most of these techniques were developed long time ago. There is an argument that significant changes have occurred in the process industry but these techniques have not been modified accordingly. Therefore, there may be limitations in identifying hazards related to the modern process industry in complex sociotechnical environment using these techniques. Recently new hazard analysis techniques based on systems theory have been introduced. STPA (System-Theoretic Process Analysis) is one of these systemic techniques. It has been used in some fields with promising results but with limited application in the process industry. This paper applies STPA to a process plant as an industrial case study. Recommendations generated by STPA are compared with the HAZOP study of the process plant which is a traditional technique. Conclusions are presented on the application of systemic techniques to the process industry as a complementary study to analyze the safety of the system as a whole and also to capture interactions between component of the system. Further studies are required to study STPA in more details and evaluate if it can be used as an alternative to HAZOP.     

基于SDG模型的HAZOP分析方法在钻井作业中的应用

HAZOP分析方法是目前危险性分析领域最盛行的分析方法之一,广泛地应用于石油化工行业。但是其分析过程仅依靠专家积累的知识与经验,不仅评价的内容不严格,而且分析的可信程度有限,对实际工作的指导意义不高,不能适应工业现场的要求。鉴于HAZOP分析方法中的不足,提出了基于SDG模型的HAZOP分析方法,并利用该方法对钻井作业过程进行了危险性分析。基于SDG模型的HAZOP分析方法从复杂系统的内部逻辑入手,进行深层次的推理,不仅提高了分析效率,而且分析所得结果的完备性较好。     

SDG-based HAZOP analysis of operating mistakes for PVC process

As modern chemical plants are becoming more complex and bigger in scale, the associated chance of things going wrong is also increasing rapidly. Due to the flammable, explosive, toxic and corrosive nature of chemical process, any single accident may trigger a major catastrophe that brings tremendous environmental, social and economical loss. In order to prevent any accident from happening, hazard and operability (HAZOP) analysis has been brought in to monitor chemical process and provide early warning for signs of accident. However, most existing HAZOP is carried out manually, and there are always obstacles in terms of cost overrun and incompleteness of the analysis. To address the difficulties in current HAZOP method, this paper proposes a signed digraph (SDG)-based HAZOP analysis method. It is used to identify the most likely operating mistakes that may cause certain process variable deviating from its normal value, which is the main source of safety concern. A case study on polyvinyl chloride (PVC) plant is presented to demonstrate the effectiveness of SDG-based HAZOP analysis method in providing complete analysis result.     

HAZOP与风险矩阵组合技术应用研究

通过对国外风险矩阵和个体风险研究,同时结合国内相关法律法规和企业事故管理规定,首次提出风险矩阵制定的依据,为企业行业制定风险矩阵提供理论基础,并制定出适合自身企业的风险矩阵。将HAZOP分析方法与风险矩阵相结合,提出"HAZOP+风险矩阵"组合技术,并采用该组合技术对精对苯二甲酸(PTA)装置氧化反应器单元的危险与可操作性问题进行系统分析,识别出装置中存在的过程安全问题并提出建议,对整个装置重大工艺安全事故的预防和安全平稳运行起到重要作用。