scholarly journals Discharge and atmospheric dispersion modelling in case of hazardous material releases

2022 ◽  
Vol 354 ◽  
pp. 00009
Author(s):  
Vlad Mihai Pasculescu ◽  
Emilian Ghicioi ◽  
Ligia Ioana Tuhut ◽  
Adrian Bogdan Simon-Marinica ◽  
Dragos Pasculescu

One of the most important tools for improving the OHS level in process industries is represented by risk analysis and assessment. Within industrial units in operation or in the ones which find themselves in the design phase, risk assessment is carried out for determining the hazards which may occur and which may lead to unwanted events, such as hazardous toxic releases, fires and explosions. Accidental releases of toxic/flammable/explosive substances may have serious consequences on workers or on the neighbouring population, therefore the need to establish safety areas based on best practices in the field and on scientific grounds is fully justified. Pressure tanks containing hazardous materials represent one of the most relevant industrial facilities within process plants, being most of the time exposed to hazardous toxic releases, fire and explosion risks. The current study aims to evaluate the consequences and discuss the safety distances required in case of an accidental release of a hazardous material from a tank located within a process plant, using process analysis software tools. Accident scenarios are modelled for comparison purposes with consequence modelling software widely used in safety engineering.

Author(s):  
Antonio C. Caputo ◽  
Fabrizio Paolacci

Resilience is a concept encompassing both the system ability to survive perturbating events which may lead to a disruption of its operations, and the rapidity in restoring system capacity after the disruptive event has occurred. While the concept of resilience has been dealt with from a number of different perspectives and in different contexts, from supply chains to networked utilities to civil infrastructures and building, research about resilience estimation of industrial facilities is lacking. In this paper a quantitative method to assess plant resilience is developed with reference to process plants and disruptive events represented by natural events such as earthquakes. The proposed method is easy to apply and amenable to both deterministic and probabilistic analysis. It provides a direct estimation of capacity loss after the disruptive event, and the time trend of recovery as well as the related economic loss. Therefore, it may provide a decision making support to facility planners and emergency managers in the process industry.


2021 ◽  
Author(s):  
Bonaventure Fontanier ◽  
Pramod Kumar ◽  
Grégoire Broquet ◽  
Christopher Caldow ◽  
Olivier Laurent ◽  
...  

<p>Methane (CH<sub>4</sub>) is a powerful greenhouse gas which plays a major role in climate change. The accurate monitoring of emissions from industrial facilities is needed to ensure efficient emission mitigation strategies. Local-scale atmospheric inversions are increasingly being used to provide estimates of the rates and/or locations of CH<sub>4</sub> sources from industrial sites. They rely on local-scale atmospheric dispersion models, CH<sub>4</sub> measurements and inversion approaches. Gaussian plume models have often been used for local-scale atmospheric dispersion modelling and inversions of emissions, because of their simplicity and good performance when used in a flat terrain and relatively constant mean wind conditions. However, even in such conditions, failure to account for wind and mole fraction variability can limit the ability to exploit the full potential of these measurements at high frequency.</p><p>We study whether the accuracy of inversions can be increased by the use of more complex dispersion models. Our assessments are based on the analysis of 25 to 75-min CH<sub>4 </sub>controlled releases during a one-week campaign in October 2019 at the TOTAL’s TADI operative platform in Lacq, France (in a flat area). During this campaign, for each controlled release, we conducted near-surface in situ measurements of CH<sub>4</sub> mole fraction from both a mobile vehicle and a circle of fixed points around the emission area. Our inversions based on a Gaussian model and either the mobile or fixed-point measurements both provided estimates of the release rates with 20-30% precision.  </p><p>Here we focus on comparisons between modeling and inversion results when using this Gaussian plume model, a Lagrangian model “GRAL” and a Gaussian puff model. The parameters for the three models are based on high-frequency meteorological values from a single stationary 3D sonic anemometer. GRAL should have relatively good skills under low-wind speed conditions. The Gaussian puff is a light implementation of time-dependent modeling and can be driven by high-frequency meteorological data. The performance of these dispersion models is evaluated with various metrics from the observation field that are relevant for the inversion. These analyses lead to the exploration of new types of definitions of the observational constraint for the inversions with the Gaussian puff model, when using the timeseries from fixed measurement points. The definitions explore a range of metrics in the time domain as well as in the frequency domain.</p><p>Eventually, the Lagrangian model does not outperform the Gaussian plume model in these experiments, its application being notably limited by the short scales of the transport characteristics. On the other hand, the Gaussian puff model provides promising results for the inversion, in particular, in terms of comparison between the simulated and observed timeseries for fixed stations. Its performance when driven by a spatially uniform wind field is an incentive to explore the use of meteorological data from several sonic stations to parameterize its configuration. The fixed-point measurements are shown to allow for more robust inversions of the source location than the mobile measurements, with an average source localization error of the order of 10 m.</p>


Author(s):  
Jae-Young Choi ◽  
Sang-Hoon Byeon

Safety showers and eyewash stations are equipment used for primary washing if their operator is exposed to hazardous chemicals. Therefore, safety showers and eyewash stations should be installed to ensure operator safety in process plants with excessive hazardous chemicals. International guidelines related to safety showers and eyewash stations are introduced in ANSI Z358.1, BS EN 15154, and German DIN 12899-3:2009, but only mechanical specifications regarding safety showers and eyewash stations are suggested. As such, there are currently no engineering guidelines, books, or technical journal papers requiring safety showers or eyewash stations and their efficient deployment. Thus, this study conducted risk assessment from an industrial hygiene perspective, suggesting which process equipment requires a safety shower and eyewash, including their economical and efficient deployment for operator safety. In industry, safety showers and eyewash stations are considered part of the process safety field; this study attempted to contribute to the safety improvement of operators by applying risk assessment of the industrial hygiene field. More studies are needed that contribute to operators’ safety by incorporating industrial hygiene fields for other process safety fields, including safety showers and eyewash stations.


2020 ◽  
Vol 10 (19) ◽  
pp. 6959
Author(s):  
Seppo Sierla ◽  
Lotta Sorsamäki ◽  
Mohammad Azangoo ◽  
Antti Villberg ◽  
Eemeli Hytönen ◽  
...  

Researchers have proposed various models for assessing design alternatives for process plant retrofits. Due to the considerable engineering effort involved, no such models exist for the great majority of brownfield process plants, which have been in operation for years or decades. This article proposes a semi-automatic methodology for generating a digital twin of a brownfield plant. The methodology consists of: (1) extracting information from piping and instrumentation diagrams, (2) converting the information to a graph format, (3) applying graph algorithms to preprocess the graph, (4) generating a simulation model from the graph, (5) performing manual expert editing of the generated model, (6) configuring the calculations done by simulation model elements and (7) parameterizing the simulation model according to recent process measurements in order to obtain a digital twin. Since previous work exists for steps (1–2), this article focuses on defining the methodology for (3–5) and demonstrating it on a laboratory process. A discussion is provided for (6–7). The result of the case study was that only few manual edits needed to be made to the automatically generated simulation model. The paper is concluded with an assessment of open issues and topics of further research for this 7-step methodology.


Entropy ◽  
2019 ◽  
Vol 21 (6) ◽  
pp. 565 ◽  
Author(s):  
Sarita Greyling ◽  
Henri Marais ◽  
George van Schoor ◽  
Kenneth Richard Uren

Fault detection and isolation (FDI) within the petrochemical industries (PCIs) is largely dominated by statistical techniques. Although a signal-based technique centered on exergy flows within a process plant was proposed, it has only been applied to single process units. The exergy-based scheme has not yet been applied to process plants that feature at least a single recycle stream. The Tennessee Eastman process (TEP) is commonly used as an FDI benchmark process, but due to obfuscation, the TEP cannot be directly implemented in a commercial process simulator. Thus, application of FDI techniques to proprietary processes will require significant investment into the implementation of the FDI scheme. This is a key impediment to the wide-spread comparison of various FDI techniques to non-benchmark processes. In this paper, a gas-to-liquids (GTL) process model is developed in Aspen HYSYS®, and the model’s performance is validated. The exergy-based FDI technique is applied to the GTL process while the process is subjected to carefully selected faults. The selected faults aim to affect several process units, and specifically, the resultant recycle stream of the GTL process is considered. The results indicate that even though the exergy-based technique makes use of fixed thresholds, complete detection and isolation can be achieved for a list of common process faults. This is significant since it shows, for the first time, that the exergy-based FDI scheme can successfully be deployed in processes with recycle streams.


2018 ◽  
Vol 10 (12) ◽  
pp. 4477 ◽  
Author(s):  
Kiyotaka Tsunemi ◽  
Kikuo Yoshida ◽  
Takehiro Kihara ◽  
Tei Saburi ◽  
Kyoko Ono

This study involves a screening-level risk assessment of the impairment of human health and life related to hydrogen explosion and chemical release during the operation of a hydrogen refueling station (HRS) that uses organic hydride. First, twenty-one accident scenarios were identified involving the leakage of hydrogen, toluene and methylcyclohexane (MCH) in the HRS. Next, the leakage frequency for each scenario was estimated using a hierarchical Bayesian model. Simulations were then performed of the blast-wave pressure and heat radiation after a hydrogen leak and of atmospheric dispersion of evaporated chemicals after leaks of liquid MCH and toluene. The consequences were estimated for each scenario according to leak size using the existing probit functions and threshold values. Finally, the risk due to explosion, heat radiation, and acute toxicity was estimated by multiplying the consequence by the leakage frequency. The results show that the mortality risk of explosion and acute effect is less than 10−6 per year, which is a negligible level of concern. However, the mortality risk of heat radiation in the scenarios involving hydrogen leakage from the pipe connected to the cylinders and compressors exceeds 10−4 per year inside the HRS, thereby requiring additional steps if a more-detailed risk assessment is needed.


2020 ◽  
Vol 12 (15) ◽  
pp. 6152 ◽  
Author(s):  
Hans Pasman ◽  
Kedar Kottawar ◽  
Prerna Jain

Resilience is the ability to restore performance after sustaining serious damage by a usually unexpected threat. This paper analyzes resilience of process plants as there are oil and gas refining, chemical manufacturing, power-producing plants, and many more. Over the years, plant safety has shifted from retrospective to proactive measures. Safety is important from many points of view, such as protection of workforce and nearby population, but certainly too from an economical and sustainability aspect. Pro-action requires predictive insight of what in the process can go wrong because of internal or external disruptive disturbance. Over the years, to that end, much effort was spent developing risk assessment methods and management. However, risk assessment has proven to be fallible because of various uncertainties and not the least by overlooked or unknown threats. To protect against those upsetting threats, measures can be taken up to a certain limit. These start in designing error-tolerant equipment able to be receptive to early warning signals during operations, responding to those with ‘plasticity’ of mind (that is, an organization and its leadership especially able to think ‘outside-the box’ for coping with unexpected situations), and finally, to deploy effective emergency response and able to recover from damage quickly. The paper presents a summary/review of nearly a decade of research work at the Mary Kay O’Connor Process Safety Center at the Texas A&M University to develop the concept and the techniques to realize a resilient plant, so far with a focus on chemical plant. It is, however, still a ‘work-in-progress’; potential is large. Besides the conceptual details, cases are presented that show how human and technical factors, combined in a socio-technical system, can lead to a broader plant safety insight enabling more effective risk control and increased resilience. These cases have up to now only considered warning signals and possible management action, while still limited to internal threats. Hence, aspects of equipment design and recovery should be further considered, also in the light of the dynamics of present-day business environment.


Author(s):  
David Tyrell ◽  
David Jeong ◽  
Karina Jacobsen ◽  
Eloy Martinez

Three recent accidents involving the release of hazardous material have focused attention on the structural integrity of railroad tank cars: (1) Minot, ND, on January 18, 2002; (2) Macdona, TX, on June 28, 2004; and (3) Graniteville, SC, on January 6, 2005. Each of these accidents resulted in fatalities. Research is being conducted to develop strategies for improving railroad tank cars so they can maintain tank integrity in severe accidents. A collaborative effort called the Next Generation Rail Tank Car (NGRTC) Project intends to use these research results to help develop improved tank car designs. Dow Chemical Company, Union Pacific Railroad, and Union Tank Car Company are the industry sponsors of the NGRTC Project. The Federal Railroad Administration (FRA) and Transport Canada participate in the NGRTC project through Memoranda of Cooperation. FRA and the Pipeline and Hazardous Materials Safety Administration intend to use these research results to support rulemaking. The approach taken in performing this research is to define the collision conditions of concern, to evaluate the behavior of current design equipment in these scenarios, and to develop alternative strategies for increasing the maximum impact speed for which tank integrity is maintained. The accident scenarios have been developed from a review of accidents and are intended to bound the range of main-line accidents that can lead to a release of hazardous material from a tank car. The accident scenarios and collision modes have been used to define car-to-car impact scenarios. These car-to-car impact scenarios define the conditions under which the commodity must be contained. The impact scenarios are being used to evaluate the integrity of current design and improved design tank cars. Full-scale impact tests are also being conducted, to help validate modeling of the baseline equipment. The models have been refined based on the test results. The models are now being applied to develop the improved equipment designs. This paper describes the overall research framework and provides an overview of the research done to date, as well as the planned efforts.


Risk Analysis ◽  
2010 ◽  
Vol 30 (4) ◽  
pp. 635-649 ◽  
Author(s):  
Nicholas Santella ◽  
Laura J. Steinberg ◽  
Hatice Sengul

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