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Hazard and operability (HAZOP) analysis has a well-deserved reputation for systematic and thorough evaluation of process hazards in industrial units. The method is now widely known and is in prevalent use in the chemical processing industries; so much so that in many industries performing a HAZOP has become a legal requirement for new or modified industrial units. A number of guides exist for conducting HAZOPs, the most recent being the IChemE guidelines on finest practice – second edition, published in the year 2008. In exercise however, following best practice is not that easy and many compromises have to be made in order to finish the task an added hurdle occurs when the HAZOP is led by a self-governing leader from an external company or third party as is increasingly the case. In this circumstance the person in charge also has to satisfy the customer or customer’s requirements which do not always match to the best custom. In addition there is a drift to lessen HAZOP study scope to safety health and environmental concerns only and to exclude operability and consistency issues. This has resulted from a observance mindset, possibly in an attempt to lessen liabilities. HAZOP is increasingly being seen as a conformity tool rather than as a tactic to ensure a secure, trustworthy and well designed plant. With the current financial environment we can expect these hitches to increase as project costs come under enhanced pressure and the extent of many projects is reduced. This paper discusses some of the more frequent crisis that occur during HAZOPs and some of the possible solutions in industrial units.

CO2 Capture Ready Process, as a part of Carbon Capture and Storage (CCS) technology, is a response to international political pressure and the priority of the European Commission to reduce anthropogenic CO2 emissions since it is connected with concerns regarding global warming. This is currently considered as an option for lessing CO2 emissions into the atmosphere. Many laboratory experiments, as well as pilot projects, have been carried out using different capture systems, but until now no experience from the one-to-one size operational installation has been gained. The energy industry must meet several challenges associated with the start-up of the new full-scale project. This paper investigates the problems that can occur while linking a new technology like the CO2 Capture Ready Process to a working fossil fuel power plant. A Hazard and Operability study (HAZOP) has been used, as it is a structured and systematic examination of a planned or existing process or operation, in order to identify and evaluate problems that may represent risks to personnel or equipment. A case study of a post-combustion CO2 capture system with an aqueous monoethanolamine as a solvent is presented, as it is the most likely system to be used in Polish power plants. Basic problems in the analysis as well as the parameters that should be considered to determine vulnerabilities of the process were successfully identified. Gaining experience about the installation’s behaviour while connected to the existing equipment of any power plant is critical for future CCS projects.

HAZOP Analysis is used to determine great deviations which will affect the operational safety of a boiler of an existing petrochemical plant that may affect on persons, material and the environment. PLC is proposed to provide the safety function to fit into the overall machine control system as a safety-related part. It reads from the temperature, pressure sensors via its input interface modules and outputs commands in the case of critical deviation via the output module to the final control elements such as actuators allowing an improvement in the safety of the overall boiler system.

Constructive literature review is the most critical aspect in research and development. Nonetheless, execution of a good literature review could be problematic due to complexity of research field. This paper discusses a new approach to implement industrial assessment practice of Hazard and Operability Analysis (HAZOP) into literature review. HAZOP methodology is originally developed to assess process hazard to ensure adequacy of process safety and operability. It is a brain storming session among expertises with the assist of deviation and guidewords to initiate hazard identification and discussions. In this paper, conventional HAZOP methodology is modified to guide literature review process. Biomass supply chain optimisation model overview is presented as demonstration case study. The system is break into sub-sections for independent analysis to ensure detailed assessment. Deviations to be included in the study are quality, quantity, logistic, and market cost/value. Potential process hazards are identified with the guidewords of more/higher, less/no and less/lower. Each identified hazard was cross-checked with the literature for potential rectification. Recommendations are provided in case of inadequacy of protection over the identified hazards which also highlighted as the potential research gaps. HAZOP approach provides a systematic platform to conduct detailed evaluation of a complex research in guided sequences.

To improve industrial safety, several hazard analyses of processes are available. The HAZOP is one of the most frequently employed and analyzes hazardous process deviations based on heuristic knowledge. Despite the wide application of the technique, new developments are especially important to enhance industrial safety. In this sense a systematic procedure is proposed for hazardous process deviation identification and analysis that employs process simulation and heuristic evaluation. Process simulation enables the analysis of process behaviors caused by device malfunctions and the performance of deviation analysis that considers the process non-linearities and dynamics. A comparison between the HAZOP and the proposed procedure is presented using a pump startup system case study, wherein the better system interpretation and results regarding abnormal process conditions are highlighted. A second case study applies the procedures to an offshore oil production process, showing the advantages of employing process simulation for studying deviation during a dynamic process’s abnormal behavior.

Currently, there is a strong demand for quantitative process risk analysis. There is a challenge in describing the process dynamic behaviour in case of failures. We suggest a methodology that combines dynamic simulation (Aspen Plus Dynamics tool), risk analysis (HAZOP review) and risk matrices. The hazardous scenarios leading to major accidents are identified, some of them are simulated which allows the determination of consequences and quantification of severity. Moreover, the knowledge of the process dynamic behaviour and the evolution of the operating parameters during a degraded mode permits adequate safety barriers recommendation. In this paper, the aim is to apply this methodology to a case study concerning an exothermic reaction in a semi-batch reactor. The chosen reaction is the oxidation reaction of sodium thiosulphate by hydrogen peroxide. Advantages and limitations of the proposed approach are revealed and discussed.

This paper analyzes the problems with selecting representative accident scenarios, which are understood as the maximum credible accidents for major industrial accidents. The selection process is based on the risk ranking scheme, which is applicable to all potential accident scenarios identified during the process hazard analysis (PHA) for a major hazard plant. Unfortunately, the process implies a substantial level of uncertainty due to incomplete and vague information concerning the assessment of the frequency and severity of the categories required for the risk ranking matrix as well as the lack of data reflecting the impact of the layer of protection on those categories. In most cases, the uncertainty is caused by insufficient knowledge and experience of the PHA team. This uncertainty usually affects the credibility of the accident scenario identification process and, by the same token, results in underestimation or overestimation of the process risk level. To address all knowledge-based uncertainties, a new approach for the identification of representative accident scenarios is proposed. This approach consists of the inclusion of a semi-quantitative assessment of the safety performance of protection layers combined with a fuzzy logic approach to risk ranking assessment. The proposed methodology may be successfully used for any major hazard industry; a case study for the fictional model of LNG storage facilities is presented here. Preliminary tests confirmed that the final results of the risk index were determined in a more precise and realistic manner.

Hazard and operability analysis (HAZOP) has developed from a tentative approach to hazard identification for process plants in the early 1970s to an almost universally accepted approach today, and a central technique of safety engineering. Techniques for automated HAZOP analysis were developed in the 1970s, but still have not displaced expensive manual approaches. Reasons for this were investigated and conclusions are drawn. The author’s actual experience in applying automated HAZOP techniques over a period of more than 30 years is revisited, including results from several full-scale validation studies and many industrial applications. Automated techniques, when combined with manual approaches, were found to provide significant improvements in HAZOP quality and a limited but valuable improvement in efficiency.

Batch, multiproduct chemical processing facilities present special challenges for conducting thorough hazard assessments. New or improved methods are needed to perform quality hazard analyses while reducing time and resource demands on facility personnel. A technique has been developed to expand traditional hazard and operability (HAZOP) methodology to include additional parameters for process operational intent, chemicals, and affected upstream/downstream equipment. Integrated Layer of Protection Analysis (LOPA) is applied to assess existing or proposed Independent Protection Layers, and compare resulting mitigated risk to risk criteria limits. The HAZOP for each unit then becomes a baseline hazard assessment, to which subsequent processes can be compared, without having to repeat the full HAZOP for each new process. For new products, a process intent template is completed by selecting the chemicals and equipment to be used, as well as the unit operations and conditions for each step in a semibatch process. The unit HAZOP file is queried using programmed search logic to identify matching process intent/equipment/chemicals parameters that were considered during the base HAZOP. A condensed Process Hazard Review is conducted to review the results, ensure identified items are applicable to the proposed new process, and evaluate new items that were not previously covered under the base HAZOP. © 2017 American Institute of Chemical Engineers Process Saf Prog, 2017

Complete, thorough, and correct process safety management depends to a large extent on complete, thorough, and correct process hazard identification, both before and during the process hazards analysis (PHA) review. Findings from the examination of incidents and disasters in industry indicate that PHA reviews fail to identify a significant number of process hazards. This is unacceptable: we cannot manage a hazard if we don't know that it exists, and incidents will continue to occur if PHA reviews continue to overlook process hazards. HAZOP is widely recognized as the standard for conducting thorough PHA reviews, but it is not the only technique available. In this paper, outcomes of three actual HAZOP reviews in the oil & gas industry are compared and contrasted with the results for the same facilities using Process Flow Failure Modes (PFFM). PFFM is a unique method, best described as a highly efficient, highly effective cross between FMEA and HAZOP, enhanced by a customized visual tool. Differences in the success rate of the two methodologies to identify process hazards are quantified and discussed with the aim of improving the industry success rate in identifying process hazards during PHA reviews in a cost-effective, straightforward manner.

Recent LNG facilities projects have grown in size and complexity (e.g., larger capacities, remote sites and modularized construction), thus requiring larger investments. This trend has not only increased the investment costs but also added further difficulties to project management during the design phase (e.g., large, joint venture organizations for both, Owner and Contractor, that combine partners with different company cultures, personnel hired specifically for the project, complicated contract formations and splits of work, and extensive and complex government permitting and approval requirements). In addition, the project schedule is also usually very tight in order to start up the facilities sooner. Recent projects apply a risk-based approach in defining and ensuring a safe design, rather than using the traditional deterministic approach. This formalized process (accountability, identification and demonstration for hazard and risk) has started since the Seveso Disaster, and has provided a new regulatory framework for the work place health and safety in Great Britain and Europe as the Safety Case Regulation following the Piper Alpha incident. However, due to the increasing project complexity, a risk-based approach and decisions based on a probabilistic cost-benefit analysis becomes inherently difficult. They require obtaining a firm output from various analyses and studies, which in turn, require firm design data that is only available at the latter stages of the design phase. Delays in HSE input to design may result in major schedule delays in project execution. The application of the risk-based approach has been the first step toward improving process safety, the next step, which is discussed in this paper, is to establish the Management System in order to effectively implement the risk-based approach in the current complex project environment and execution. Typical problems observed in such complex projects are differences in problem statements and optimal outcomes when there are multiple stakeholders, different philosophies, insufficient coordination and inefficient design change control, all leading to inconsistencies in HSE design. The HSE management system (HSE MS) typically focuses on site occupational HSE. However, due to the increased difficulties in engineering execution and project management in recent projects, detailed planning of how to handle Technical HSE aspects in engineering is becoming more and more important, and therefore, the traditional application of the HSE MS for occupational safety and for preparing HSE procedures and organizing and managing HSE studies (e.g., HAZID, HAZOP and SIL) do not suffice. Detailed consideration of how to handle and manage the Technical HSE aspects in engineering is critical for its successful implementation. This paper discusses a framework for the effective management of HSE MS in the design phase, and it provides some key considerations (e.g., philosophy of safety in engineering, project environment evaluation method, HSE organization and the recommended scheme for improving motivation for safety).

Hazard identification is the first and most crucial step in any risk assessment. Since the late 1960s it has been done in a systematic manner using hazard and operability studies (HAZOP) and failure mode and effect analysis (FMEA). In the area of process safety these methods have been successful in that they have gained global recognition. There still remain numerous and significant challenges when using these methodologies. These relate to the quality of human imagination in eliciting failure events and subsequent causal pathways, the breadth and depth of outcomes, application across operational modes, the repetitive nature of the methods and the substantial effort expended in performing this important step within risk management practice. The present article summarizes the attempts and actual successes that have been made over the last 30 years to deal with many of these challenges. It analyzes what should be done in the case of a full systems approach and describes promising developments in that direction. It shows two examples of how applying experience and historical data with Bayesian network, HAZOP and FMEA can help in addressing issues in operational risk management.

Failure Mode, Effects and Criticality Analysis (FMECA) is a well-known method used in safety analysis, reliability analysis, risk assessment and maintenance objectives. Moreover, in the manufacturing domain and particularly in the context of the deployment of the factory of the future, its usage is not entirely satisfactory in relation to the indicator to be observed. Thus, the paper presents a new methodology based on a coupled approach of FMECA and Hazard Operability analysis (HAZOP) which aim is to contribute to the deployment of proactive maintenance strategies by clearly identify pertinent indicator. This approach is based on the formalization of concepts of knowledge which permit to constitute the first pillars of proactive maintenance approach. Applicability of this methodology is illustrated on a machining center sub-system.

Process safety is one of the key pillars of sustainable industrial development. In combination with the increasing use of computer aided process engineering, the demand for an appropriate model-based safety analysis tool capable to identify all hazardous situations leading to a major accident has increased. Commercial process simulators are equipped with extensive property databases and they employ high accuracy mathematical models providing the capability to simulate real behavior of a process operated within the area of the mathematical model validity. The main focus of this work is to improve standard hazard identification methods by the combination of hazard and operability (HAZOP) study and process simulation in commercial process simulator Aspen HYSYS. Software tool consisting of modules for computer simulation and complex analysis of simulation data will be proposed. The developed tool was applied to modern chemical productions exhibiting strong nonlinear behavior, where proper prediction of consequences can be very difficult. In the first case study, hazard identification in continuous glycerol nitration employing user-dependent analysis is presented. Mathematical methods of simulation data analysis independent of the user is demonstrated in the second case study of ammonia synthesis. Possibilities and limitations of the proposed tool are revealed and discussed in this work.

Layer of Protection Analysis (LOPA) has gained popularity as a semi-quantitative risk assessment tool, but often unexpected difficulties are encountered when rolling out LOPA. This article discusses the practical aspects of LOPA implementation in Marathon Petroleum Company LP's Refining Organization (MPC Refining). Specifically, it shows how scenarios are selected from a Hazard and Operability Study (HAZOP) and how they are organized for conducting LOPA efficiently, and it discusses whether to conduct LOPA concurrently or after the HAZOP. The article also compares the [cause → consequence] or [consequence → cause] methodology and addresses the implications of combining multiple causes in a single scenario. Another key aspect of LOPA implementation is the set of numerical values used for frequencies, modifiers and risk-reduction factors. The article shows how numerical values should be tied to the risk matrix and how internal consistency is achieved through the use of standardized values and restrictions on the use of frequency modifiers. It discusses potential solutions for cases where the LOPA outcome does not meet the risk target. Finally, the article shows how the use of application standards can supplement LOPA by defining minimum protections and providing standard LOPA scenarios. © 2017 American Institute of Chemical Engineers Process Saf Prog 36: 284–291, 2017

Product modernisation and upgrade are driven by the demand to maintain technological update and to increase product operational life. To accomplish those tasks a set of potential solutions are proposed involving engineering changes in original product design. This paper presents a method to support the selection of the most suitable design solution based on the quantification of risk profile and cost of each alternative considering the architectural modification relative to a baseline design. Design Structure Matrix is used to analyse the product original design and the changes required to accommodate alternatives proposals and risk is quantified based on Hazard and operability study analysis and characterised as the effects of components of faults and failures on product performance. The proposed method is applied to an armoured personnel carrier major overhaul when the effects of introducing design changes, including powertrain modification, are quantified in terms of risk and costs. The propose...

This article shows how to apply the qualitative definition of IPLs within the setting of a process hazard analysis (PHA) to get most of the gain from Layer of Protection Analysis (LOPA) without doing a LOPA (without using numerical values). The article includes an implementation path to develop PHA leader competencies to guide the qualitative approach. We also show the way we use a PHA team to identify when a SIF is needed and to select the proper target safety integrity level (SIL). This portion of the SIL evaluation and the identification and labeling of the IPLs during the PHA/hazard and operability analysis (HAZOP) does not take any longer than a normal PHA/HAZOP, once the right habits are established. Note that this approach eliminates the need for a separate SIL Evaluation Study to identify the SIFs and select the target SIL. Finally, the article ties together these two specific topics, along with the topic of making risk judgments, to show there is less than 5% need to go beyond HAZOP, and less than 0.01% need to go beyond LOPA. © 2016 American Institute of Chemical Engineers Process Saf Prog 35: 349–359, 2016

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.

While safety is the number one consideration for plant designers, and sustainability is important, these things cost money. Engineers care about costs, so we balance improvements in safety and sustainability against them. Generally, we aim to make plants just as safe and sustainable as is legally required, though ethical consideration may cause us to exceed the minimum standard on occasion.

Objectives/Scope Hazard identification is one of the most important activities carried out in the Safety Instrumented System (SIS) safety lifecycle [1]. Proper hazard identification and analysis of its risk lays the foundation of the SIS design. Methods, Procedures, Process The common method for a structured study for the hazard identification is Hazard and Operability Study (HAZOP) study. The concepts of HAZOP are well evolved and applied for over five decades. The basic premise for HAZOP considers plant design is mature enough and sufficient design information on the plant operation is available. HAZOP process involves breaking down of complex process into simpler sections which are termed as nodes. These individual nodes are then studied for identifying the potential hazards and operability problems. STAMP (System-Theoretic Accident Model and Processing) [2] is accident causality model based on systems theory. STPA (System Theoretic Process Analysis) is one of the STAMP based tool which is a relatively new hazard analysis technique based on an extended model of accident causation. STPA is a proactive analysis method that analyzes the potential cause of accidents during design development so that hazards can be eliminated or controlled. Conventional studies like HAZOP considers deviations or component failures as cause for what may go wrong and cause accident. STPA assumes that accident may also be caused due to unsafe interactions of the system components, none of which have failed.

Occupational Safety and Health (OSH) is a safe and healthy condition when doing work. This safe and healthy condition are useful for both workers, companies or organizations and for the environment around the workplace. OSH is an important aspect in workshop, including CV. Epen Garage X Azizskip which is a motorbike repair workshop located in Citeuteup area, Bogor City, West Java. OSH will be created if there is no potential danger or hazard, therefore it is necessary to identify hazards in the workshop. This study aims to identify hazards using Hazard and Operability Study (HAZOP) method and work improvement using Seiri, Seiton, Seiso, Seiketsu dan Shitsuke (5S) method. The types of hazards, risk levels and sources of hazards will be identified by the HAZOP method. Generally the hazards in the workshop are because workers do not use Personal Protective Equipment (PPE) such as work clothes, gloves, safety shoes, safety goggles and also messy workshop condition. After identifying the types of hazards, a work improvement method is needed to prevent accidents in workshop, using the 5S method.

The traditional hazard analysis approaches applied to the socio-technical system cannot cover the complex organization structures, the interactions between systems and human behaviors, the interrelated factors among sub-systems and the safety culture of specific societies. This paper presents an integrated hazard identification approach named System-Theoretic Process Analysis Based on Formalization Model (BFM-STPA), which can solve the above issues. Firstly, the hierarchical control structure models of the socio-technical system are established through Colored Petri Nets (CPN) due to its strong description ability and executable ability, which may also be regarded as the graphical system specification. Secondly, the hazards can be identified according to the CPN models following a series of guide conditions. Thirdly, the comprehensive contributing factors to the hazards will be found out by tracing the former states within the reachability graph generated from CPN model. Finally, an integrated hazard log can be derived for further hazard analysis and safety-guided design. In this paper, the above method was applied in the Chinese Train Control System level 3 (CTCS-3). And the process of hazard identification for the scenario of Temporary Speed Restriction issued was elaborated in detail. Compared with the hazard log generated by Hazard and Operability (HAZOP), the hazard log generated by BFM-STPA covered not only the subsystem failures, but also the deviation of interactions among subsystems from design intent, human errors and socio-technical drawbacks related to the TSR Issued scenario of CTCS-3. Language: en

A hazard and operability study (HAZOP) is a structured and systematic examination of a planned or existing process or operation in order to find and evaluate problems that may represent risks to personnel or equipment, or prevent efficient operation. The qualitative HAZOP uses keywords for generating deviations from safe condition and ensures that appropriate safeguards are in place to prevent accidents. WHIPP or Walkdown Hazard Identification for Plant and Process is a hazard identification technique which can be applied to chemical plants, but with modification can be tailored for many industry types. The method adopts a checklist approach to hazard identification which enables auditors and plant operators to carry out plant walkdowns easily and effectively. But there is a high difference between a qualitative hazard identification method and audit type method since HAZOP is mainly used in a process industry and an audit is mainly used for inspecting the safety management of the industry thus in the WHIPP they used guidewords same as HAZOP uses keywords to identify the hazards and risks associated with the hazards while they perform the walk down in the company and are assessed with a checklist. This paper is the comparison of the two methods to see which is more efficient and which is more reliable in the process industries as well as normal industries.

Hazard and operability (HAZOP) analysis approach based on sensitivity evaluation is presented in this paper to ensure production safety in complex and large-scale chemical plants. In this approach, the sensitivity evaluation is introduced into HAZOP deviation analysis to measure the effect degree caused by each cause on the corresponding deviation. A quantitative sensitivity evaluation model of deviation cause is first established, in which the departure degree, time duration to reach the maximum deviation, and stability degree of the target process variable are determined as evaluation factors. The sensitivity evaluation of each deviation cause is performed based on the dynamic process simulation. The multiple deviation causes that correspond to the deviation are ranked based on sensitivity index, thereby identifying the significant effect causes on deviation from multiple causes; this identification will assist plant operators and safety management staff on their on-line process monitoring and fault diagnosis. Finally, the proposed approach is applied to the depropanization unit in a gas fractionation plant. The sensitivity evaluation was carried out for 10 deviation causes that correspond to the deviation "higher overhead pressure", in which three and seven sensitive and non-sensitive causes were identified, respectively. The result of the case study demonstrates that the proposed approach can improve the readability and guidance of conventional HAZOP report, which is consistent with the actual production conditions. Language: en

The HAZOP and LOPA methods are commonly used for qualitative hazard identification and semi-quantitative assessment of risk in the process industries. Integration of HAZOP and LOPA techniques into a single study has provided the practical advantage of utilizing the same team of subject matter experts to complete evaluation of hazard scenarios, identify needs for further risk reduction, recommend specific safeguards required and confirm resulting residual risk is acceptable. While practical and efficient, the one-step comprehensive integrated HAZOP/LOPA method can have pitfalls. In particular, use of LOPA alone to confirm risk acceptability can lead to complex solutions to meet order-of-magnitude threshold requirements for risk reduction and restrictive requirements for independent protection layers (IPLs). Quantitative methods are sometimes required beyond HAZOP/LOPA to obtain a more precise evaluation of identified hazards and benefits of the associated safeguards. This article presents a risk assessment approach incorporating advanced analysis, including human factors task, fault tree and cost-benefit analysis, following HAZOP/LOPA analysis. To illustrate this approach, an example is shown on the selection of appropriate engineering design options for cyclic regeneration of dense phase ethylene treaters, which have unique safety concerns. Using advanced analysis, a cost effective design solution is developed and is shown to reduce risk to as low as reasonably practicable (ALARP). © 2016 American Institute of Chemical Engineers Process Saf Prog 36: 192–201, 2017

It is analyzed to control the affection for dynamic affection of change in process parameters to the corrosion of equipment and pipes with the HAZOP, LOPA and corrosion self-healing control system, then HAZOP-LOPA–Based corrosion risk identification and control technology is proposed to improve the level of effective active control in high-risk corrosion in the petroleum–chemical process in this paper.

The aim of our work was the implementation of a new automated tool dedicated to risk analysis and assessment in petrochemical plants, based on a combination of two analysis methods: HAZOP (HAZard and OPerability) and FMEA (Failure Mode and Effect Analysis). Assessment of accident scenarios is also considered. The principal advantage of the two analysis methods is to speed-up hazard identification and risk assessment and forecast the nature and impact of such accidents. Plant parameters are analyzed under a graphical interface to facilitate the exploitation of our developed approach. This automated analysis brings out the different deviations of the operating parameters of any system in the plant. Possible causes of these deviations, their consequences and preventive actions are identified. The result is risk minimization and dependability enhancement of the considered system.

This paper presents a study on the risk of corrosion within a post-combustion and amine-based carbon capture installation with the use of selected risk assessment methods like the HAZard and OPerability study (HAZOP), Delphi technique and Fault Tree Analysis (FTA). As in alkanolamine plants, due to economic reasons most of the equipment and piping is constructed of carbon steel, these parts of the installations may suffer from corrosion by several agents like wet acid gases, oxygen and products of the degradation of amines. The study presented within this paper shows this does not only occur in the case of carbon steel, but also other types of materials used within the installation may suffer from corrosion. The correct choice of materials is vital in ensuring the long-term performance, safety and operational availability of CO2 capture plants. A lack of information about previous operational problems or accidents within one-to-one size installations presents a great challenge when conducting risk assessment. This is why a methodology of risk identification and evaluation for CO2 capture installations is proposed, along with its practical application. This method is based on the experience gained from worldwide pilot plants and from a Polish research project on the CO2 capture process. All new technologies need to be investigated with special care, especially when having little knowledge about their behaviour while connected to the existing equipment of any power plant.

As electric and electronic control systems have sharply increased in vehicles, safety accident has emerged as an important issue. Therefore, in order to ensure safety of the vehicle, engineers are required to identify the hazards utilizing PHA and HAZOP, etc. in the early phase of development and implement safety mechanisms to prevent them. HAZOP has been widely used in a systematic manner based on guidewords. However, HAZOP identifies malfunctions from the top-level functionality provided by the system, so it cannot sufficiently identify hazards during the system operation. This leads to restrictions in designing testcases, because the safety requirements are derived from only some of the hazards. This research aimed to provide a hazard identification method utilizing Use case description, which defines operation procedure of the system and HAZOP and a testcase design method based on safety requirements. We introduced a case study on Smart Key Control System in vehicles and compared with hazards identification results based on HAZOP, to demonstrate the effectiveness of this study. The result of this study could potentially reduce development cost and increase system quality by adequately identifying hazards and safety requirements and designing the related testcase.

In order to remain economically effective and financially profitable, the modern industries have to take their safety culture to a higher level and consider production losses in addition to simple accident prevention techniques. Ideally, compliance with safety requirements start during early design stages, but in some older facilities provisions for Safety Instrumented Systems (SIS) may not have been originally included. In this paper, a case study of a Reheater Drains (RD) system is used to illustrate such an example. Frequent failures of tank level controller lead to transients where the operation of shutting down RD pumps requires operators to manually isolate the quenching water and to close the main steam admission valves. Water in this system is at saturation temperature for the reheater steam side pressure, and any manual operation of the system is highly undesirable due to hazards of working with wet steam at approximately 758 kPa(g) pressure, preheated to 237 °C. Additionally, losses of inventory are highly undesirable as well and challenge other systems in the plant. In this paper, it is suggested that RD system can benefit from installation of an independent SIS system in order to address current challenges. This idea is being explored using IEC 61508 framework for “Functional safety of electrical/electronic/programmable electronic safety-related systems” to provide assurance that the SIS will offer the necessary risk reduction required to achieve required safety for the equipment.

Process safety has undergone a tremendous growth over the last decades, both in terms of required competencies and in terms of market demand. Although its cultural background mainly consists of the traditional subjects of chemical and process engineering, a multifaceted range of expertise has made it autonomous and different from the general chemical engineering frame: the interdisciplinary degree is much wider, the relevant regulations and standards have become so stringent and specific to become a key driver for the scientific and technical development of the discipline, its current growth trend is probably incomparable to others, role and functions of process safety engineers have acquired more significances and implications in the industrial scenario. This article considers the learning lessons of a long tutoring and teaching activity that the author has carried out in process safety between university and industry in Europe and in Asia. The findings have been analysed and converted into specific indicators and trend data, with the aim to contribute to reduce the significant gap which still exists in a branch of chemical engineering that is expected to increase its complexity and importance in the near future.

The catastrophic explosion that occurred at Texas City on 23 March 2005 during the start-up of the raffinate splitter resulted in an estimated 15 deaths and 180 injuries. Since the incident, several studies have investigated the root causes of the disaster. Some contributing factors to the incident include wider organisational, process safety management, and human elements. There have also been some attempts to model the sequence of events before the incident, and the consequences of the resulting fires and explosions. This study provides a dynamic model of the sequence of events leading up to the incident and replicates the reported process variables during the isomerisation unit start-up on the day of the incident. The resulting simulation model is used as the framework for a dynamic hazard and operability (HAZOP) study.

Hazard and operability (HAZOP) analysis is one of the most widely used methods for process hazard analysis. However, the outcome of HAZOP analysis could result in identifying large number of hazards, thus posing a challenge for assessors to take actions in dealing with all the hazards. The common practice in prioritizing the critical hazards is based on assessors’ experience through deductive judgment using rating scale, taking into consideration safety and the associated costs. Although being simple and straightforward, HAZOP has the disadvantage of lacking systematic approach to elucidate different conclusions into an integrated outcome, thus susceptible to inaccurate and unjustified decisions. In this paper, we present a structured methodology for incorporating prioritization in HAZOP analysis using analytic hierarchy process. Through this approach, the hazards of a process identified using HAZOP will be quantitatively weighted and ranked based on their priority along with the appropriate counter measures to be taken. The proposed methodology is a thorough decision-making tool as it does not only prioritize the hazards identified from the HAZOP assessment, but also provides medium for the assessors to quantitatively analyze the hazards. To show its efficacy, the approach will be applied to a simple reactor unit and a more complex system of dividing wall column pilot plant as case studies. The result shows that the proposed methodology is capable of identifying and ranking the most significant hazards in a process following HAZOP analysis. This is particularly useful, especially to process designers/engineers in prioritizing their efforts and resources on more significant hazards, hence aiding toward achieving an inherently safer chemical process.

Background: Prevention of accidents—a crucial requirement in oil industries—involves hazard recognition, risk assessment, and corrective actions. The purpose of this study was to compare the ETBA and HAZOP techniques for risk assessment in a gasoline refinery unit. Methods: In this case study, data were collected using process flow diagram, walking–talking through method, piping and instrumentation diagram, and direct observations. Worksheets for both techniques were filled on the basis of the risk assessment matrix MIL-STD-882E. Results: The HAZOP method identified 44 deviations attributable to 118 causes. In addition, 11.37% of the identified hazards were associated with unacceptable risk, and 36.36%, with unfavorable risk. The ETBA method detected 10 groups of energy (24 subgroups); 33 hazards were detected, 10.62% of which were associated with unacceptable risk. Conclusion: HAZOP proved to be the more powerful technique for the prediction and identification of hazards. However, ETBA detected certain hazards that were not identifiable using HAZOP. Therefore, a combination of these two methods is desirable for the assessment of hazard risk in process industries.

Many technological systems that are composed of technical parts embedded in human, organizational, and environmental contexts can be categorized as complex systems. They have various interactions and a nonlinear relationship between their components. They are also open to their environment and make exchanges with it. Almost all traditional risk assessment techniques, such as Failure Modes and Effect Analysis (FMEA), Hazard and Operability Analysis (HAZOP), Fault Tree Analysis (FTA), and Probabilistic Risk Analysis (PRA) rely on a chain of linear cause and effect analysis. These techniques also have some limitations in terms of incorporating efficient links between risk models and human and organizational factors for studying modern complex technological systems. This paper generally reviews existing approaches of risk assessment for complex technological and specifically studies risk assessment of wind turbines. Then it proposes an integrated risk assessment framework for complex technological systems through a Bayesian network considering various system levels and their interaction using a cause and effect approach. Since wind turbines are instances of complex power generating systems consisting of several structural, electrical, and mechanical components interacting with human resource and organizational factors within natural, political, economic, and social environments, the proposed model is applied to assess risk and reliability in a wind turbine. Different scenarios of reliability analyses were investigated, which illustrated that Bayesian networks are effective for the reliability assessment of the chosen system and very useful for understanding the system behavior.

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.

Young practicing chemical engineers must be able to operate safely in an industrial setting. Therefore, chemical process safety education is essential for undergraduate chemical engineers and ABET (the University Accreditation Board) supports this initiative by requiring that university graduates understand the hazards associated with chemical processes. One way to understand the hazards associated with processes is to conduct a process hazard analysis. This analysis can be conducted in an experiential learning environment by collaborating with an industrial partner or by utilizing facilities on the university campus. In this environment students are able to see and interact with the processes under normal operating conditions. Utilizing industrial or research mentors allows students to receive formative feedback as they analyze the process. In addition, these process hazard analyses require students to practice “soft skills” such as teamwork, problem solving, and oral and written communication which are essential work place skills. This paper reviews teaching hazard analysis methods to chemical engineering students at the undergraduate and graduate levels. Covered are examples of how students are introduced to the checklist and bowtie analysis methods, and the conduction of a HAZOP. Examples of the different resources that can be utilized are described. Ultimately, from these experiences, students are more prepared to enter the chemical process industries with first-hand knowledge of how to conduct various hazard analyses before reaching their place of employment.

This chapter introduces the safety analysis method of train control systems, including qualitative analysis methods, quantitative analysis methods, and STPA (System-Theoretic Process Analysis). The qualitative method introduces safety checklist analysis, preliminary hazard analysis (PHA), failure mode and effect analysis (FMEA), and hazard and operability analysis (HAZOP); quantitative analysis method introduces the fault tree analysis (FTA), event tree analysis (ETA), and stochastic Petri net analysis. Finally, a causality model based on the system theory is described, that is, STAMP (Systems-Theoretic Accident Modeling and Processes), and a new approach based on STAMP to hazard analysis is described, called STPA.

CCPS (2005) defines chemical process quantitative risk analysis as the quantitative evaluation of expected risk from potential incident scenarios. It examines both consequences and frequencies, and how they combine into an overall measure of risk . In process safety, the quantitative risk analysis is a preliminary step, aiming to obtain a final quantitative risk assessment (QRA), in order to ensure that risk is mitigated, controlled, and can be accepted according to some validated criteria. Process safety engineering does not deal only and always with QRA, however most of qualitative and semiquantitative studies, such as HAZID, HAZOP, PHA, FMECA, usually adopt a quantitative parametrisation to risk ranking. Regardless of this, all process safety engineering tasks contribute to ensure that any quantifiable risks demonstrably fall within the limits. The QRA world encompasses a multifaceted series of exercises, which present a different degree of complexity and difficulty. Regardless, all of these are approached through the combination of hazard scenarios, which are identified according to the techniques of consequence assessment, with the corresponding probabilistic levels of occurrence. A particular importance is given to the risk associated to Major Hazard Installations, which are regulated by very stringent and comprehensive international laws and standards, such as the Seveso Directives/COMAH in Europe, and the EPA Risk Management Program Rule in USA. In addition, a plethora of standards and regulations, both in Europe and in the USA, require undertaking a lot of QRA-based studies as a support for an appropriate and safe design. Among these, hazardous area classification, functional safety, reliability review, and even the registration of a new chemicals within the REACH regulation framework are quantitative risk-based processes. A full coverage of the QRA scenario would deserve a whole volume, so the systematic description of the methodology and of the associate techniques is out of the scope of this book. Nevertheless, most parts of the concepts and the theoretical aspects underpinning the execution of a QRA have largely been. In this chapter, an overview of the techniques has been provided, referring, when required, to the specific chapters where consequence assessment and probabilistic aspects have been treated.

The Bhopal disaster was a gas leak incident in India, considered the world's worst industrial disaster happened around process facilities. Nowadays the process facilities in petrochemical industries have becoming increasingly large and automatic. There are many risk factors with complex relationships among them. Unfortunately, some operators have poor access to abnormal situation management experience due to the lack of knowledge. However these interdependencies are seldom accounted for in current risk and safety analyses, which also belonged to the main factor causing Bhopal tragedy. Fault propagation behavior of process system is studied in this paper, and a dynamic Bayesian network based framework for root cause reasoning is proposed to deal with abnormal situation. It will help operators to fully understand the relationships among all the risk factors, identify the causes that lead to the abnormal situations, and consider all available safety measures to cope with the situation. Examples from a case study for process facilities are included to illustrate the effectiveness of the proposed approach. It also provides a method to help us do things better in the future and to make sure that another such terrible accident never happens again.

Hazard and operability analysis (HAZOP) is widely applied in petroleum industry as a scientific and effective safety analysis method, but it is traditionally qualitative in essence and hereby has such shortages as vague conclusions, susceptible to human factor, lack of comprehensive consideration, and so on. This paper proposed a dynamic simulation-based quantitative HAZOP method that utilizes dynamic simulation to reason deviations to reduce uncertainty in manual analysis. It transforms deviations into quantitative dynamic tasks and uses these tasks to activate dynamic simulation for quantitative deviation reasoning work. The possible consequence and propagation time caused by deviation is probed by analyzing simulation results. In this process, some deviations that appeared seldom or did not at all before can also be simulated and analyzed with the aid of dynamic mechanism model. Case studies in extractive distillation and ammonia synthesis loop showed that this method can present propagation effect of key process parameters on safety state and is useful for iterative and automatic assessment work. It is also found that detailed operation and device data are necessary for initial complex process modeling. In addition, we should improve simulation platform to meet practical requirements when applying this method. © 2015 Curtin University of Technology and John Wiley & Sons, Ltd.

This paper presents a method for determining the optimal order of HAZOP nodes, as well as the issues related with a description of streams flows of information among the elements of process systems. Determination of the optimal HAZOP nodes sequence (a sequence of nodes being sources of information streams are analyzed before the nodes receiving the streams) allows avoiding the necessity of assuming and afterward verifying an existence of possible deviation and their transmission from the upstream nodes to the one being the subject of the analysis. This procedure constitutes a difficult task for process installations with a complicated structure. The optimal order of HAZOP nodes can be determined by using the graph theory and the matrix calculus. The described method has been implemented to carry out analyzes of complicated process systems. The main rules of the proposed method and results of application are HAZOP analyzes of steam boiler plant and one of the Underground Gas Storage Plant operated in Poland are presented in the paper.

The ability to perform an effective and robust safety analysis on the design of modern safety–critical systems is crucial. Model-based safety analysis (MBSA) has been introduced in recent years to support the assessment of complex system design by focusing on the system model as the central artefact, and by automating the synthesis and analysis of failure-extended models. Model checking and failure logic synthesis and analysis (FLSA) are two prominent MBSA paradigms. Extensive research has placed emphasis on the development of these techniques, but discussion on their integration remains limited. In this paper, we propose a technique in which model checking and Hierarchically Performed Hazard Origin and Propagation Studies (HiP-HOPS) – an advanced FLSA technique – can be applied synergistically with benefit for the MBSA process. The application of the technique is illustrated through an example of a brake-by-wire system.

The safe operation of Chinese Train Control System Level 3 (CTCS-3) is of great significance, particularly with respect to the increasing operational speed and expanding railway networks of the Chinese high-speed railway system, which has drawn deep concern from both customers and strategic makers. A hazard and operability (HAZOP) study has been recognized as an effective systematic examination to identify any potential problems existing in various industrial processes or operations. This paper presents a process of applying a HAZOP study to identify the hazards of a CTCS-3 onboard system for the first time, which is composed of two major parts: system models and hazard identification on the examination session. To better reflect the structure and functions of a CTCS-3 onboard system, the following models are developed, i.e., a reference model, a function hierarchical model, a state diagram, and a sequence diagram. To demonstrate the effectiveness of the HAZOP study, hazard identification on the basis of the functions of the CTCS-3 onboard system and a scenario of temporary speed restriction is considered and employed. The results indicate that existing hazards can be dug out at express speed, which allows the relevant actions to be proposed and implemented to prevent the hazards from spreading to a wide range in the whole CTCS-3 onboard system.

Conventional wisdom holds that the Hazard and Operability (HAZOP) study is the most thorough and complete process hazard analysis (PHA) method. Arguably, it is the most commonly-used PHA method in the world today. However, the HAZOP study is not without its weaknesses, many of which are not generally recognized. This article provides a critique of the method to assist study teams in compensating for them to the extent possible and to help guide the development of improved methods.

Given their potentially enormous risk, process monitoring and fault diagnosis for chemical plants have recently been the focus of many studies. Based on hazard and operability (HAZOP) analysis, kernel principal component analysis (KPCA), wavelet neural network (WNN), and fault tree analysis (FTA), a hybrid process monitoring and fault diagnosis approach is proposed in this study. HAZOP analysis helps identify the fault modes and determine process variables monitored. The KPCA model is then constructed to reduce monitoring variable dimensionality. Meanwhile, the fault features of the monitoring variables are extracted, so then process monitoring can be performed with the squared prediction error (SPE) statistics of KPCA. Then, multiple WNN models are designed through the use of low-dimensional sample data preprocessed by KPCA as the training and test samples to detect the fault mode online. Finally, FTA approach is introduced to further locate the fault root causes of the fault mode. The proposed approach is applied to process monitoring and fault diagnosis in a depropanizer unit. Case study results indicate that this approach can be applicable to process monitoring and diagnosis in large-scale chemical plants. Accordingly, the approach can serve as an early and reliable basis for technicians’ and operators’ safety management decision-making.

Natural Gas Transportation requires Natural Gas to be in its Liquid state, liquefying Natural Gas requires decreasing temperature to a very low level. This requires severe temperature and pressure conditions. This paper will discuss a risk assessment study on a Node in the plant of Natural Gas, which is the propane heat exchanging unit, which decreases the temperature of the flow gradually at the beginning to remove heavy liquids. Risk assessment study is applied using three methods, HAZOP, DMRA and LOPA.