Chemical Leakage Research Articles

Investigation of on the Occurrence of Industrial Accidents and Accidental Deaths by Chemical Leakage and Skin Contact

Investigation of on the Occurrence of Industrial Accidents and Accidental Deaths by Chemical Leakage and Skin Contact

유해화학물질 유출사고 대응 훈련 시나리오 적용 방안 모색

유해화학물질 유출사고 대응 훈련 시나리오 적용 방안 모색

Mean escape time for randomly switching narrow gates in a steady flow

The escape of particles through a narrow absorbing gate in confined domains is a rich phenomenon in various systems in physics, chemistry and molecular biophysics. We consider the narrow escape problem in a bounded annular when the two gates randomly switch between different states with a switching rate k between the two gates. After briefly deriving the coupled partial differential equations for the escape time through two gates, we compute the mean escape time for particles escaping from the gates with different initial states. By numerical simulation under nonuniform boundary conditions, we quantify how narrow escape time is affected by the switching rate k between the two gates, arc length s between two gates, angular velocity w of the steady flow and diffusion coefficient D. We reveal that the mean escape time decreases with the switching rate k between the two gates, angular velocity w and diffusion coefficient D for fixed arc length, but takes the minimum when the two gates are evenly separated on the boundary for any given switching rate k between the two gates. In particular, we find that when the arc length size ε for the gates is sufficiently small, the average narrow escape time is approximately independent of the gate arc length size. We further indicate combinations of system parameters (regions located in the parameter space) such that the mean escape time is the longest or shortest. Our findings provide mathematical understanding for phenomena such as how ions select ion channels and how chemicals leak in annulus ring containers, when drift vector fields are present.

Dispersion Characteristics of Hazardous Gas and Exposure Risk Assessment in a Multiroom Building Environment.

The leakage of hazardous chemicals during storage and transport processes is a kind of commonly occurring accident that can pose a serious threat to people’s lives and property. This paper aims to investigate the airflow and dispersion characteristics of hazardous gas around a multiroom building, and evaluate the corresponding exposure risks. The effects on indoor air quality (IAQ) when polluted air enters a room under different indoor and external conditions were examined by using a computational fluid dynamics technique. First, the numerical model established herein was verified by the available wind-tunnel experimental data, and acceptable agreement was found between the predicted and measured velocities. Subsequently, the effects of different natural ventilation paths, wall porosities and outdoor pollutant source characteristics on the airflow and contaminant distribution were evaluated. The study not only reveals the airflow pattern and concentration distribution in indoor spaces under different natural ventilation conditions but also quantitatively analyzes the relationship between the probability of death and the corresponding source strength under the circumstance of pollutant leakage near a building. The results can be useful for the prevention and control of hazardous chemical gas leakages and provide some guidance on evacuation after an accidental or routine leakage.

Safety Guarantee System of Drinking Water Source in Three Gorges Reservoir Area and Its Application in Huangjuedu Drinking Water Source Area

With China’s rapid economic growth and increasing speed of urbanization, water pollution accidents have become one kind of environmental pollution source in China and bring potential risk to urban drinking water safety. The Huangjuedu Drinking Water Source Area is an important water source in Chongqing City (Southwest China) and a water intake source for the Jiangnan Waterworks of the Chongqing Drinking Water Company. There are still risks of water pollution accidents caused by ship leakage, road traffic accidents, chemical plant leakage, etc. The safety of the drinking water area is related to regional residents’ health and life safety and also has a profound impact on economy development and social stability. To reduce the harmful impacts of water pollution, it is of great scientific value and practical significance to analyze the pollutant diffusion of water pollution accidents with the Three Gorges Reservoir Area drinking water source security platform. In this paper, a two-dimensional water quality monitoring model was applied, and the digital elevation model was incorporated into the geographic information system, which generated a computational grid. Then, the Three Gorges Reservoir Area drinking water source security platform was developed. The platform can predict the water flow velocity, pollutant concentration at the drinking water inlet, and the spatial and temporal distribution of pollutants in the whole water source area. Furthermore, a hypothetical ammonia nitrogen leak accident was analyzed using this safety platform. The ammonia nitrogen concentration at the intake of the drinking water source area was detected and analyzed by the security platform from the time of the accident until the concentration dropped to the background during four water periods under different wind direction conditions. The pollutants took 19, 22, 25, and 40 min to reach the water quality standard during the four water periods. Moreover, the diffusion of ammonia nitrogen in the southeast wind was faster than that in the southwest wind. The results showed that the platform is scientific and practical, and the prediction results are helpful for the Emergency Management Department to quickly and accurately predict the migration of ammonia nitrogen pollution and make corresponding plans under accident conditions.

Preparation of magnetic, superhydrophobic/superoleophilic polyurethane sponge: Separation of oil/water mixture and demulsification

Regular problems faced due to chemical leaks and oil spills have caused tremendous threats to lakes and sea water. Therefore, there is an urgent need to develop efficient strategies to remove oil and organic pollutants from water surfaces. The aim of this study is to develop a high performance magnetic, superhydrophobic/superoleophilic three-dimensional porous composite material for efficient and selective adsorption of organic pollutants from water. The composite material was fabricated by simple immersion of a commercially available polyurethane (PU) sponge into a solution of high-density polyethylene (HDPE) containing pre-synthesized magnetic (Fe3O4) nanoparticles. The composite material exhibited a water contact of ~155° and an oil contact angle of ~0°. The presence of the Fe3O4 particles allowed magnetic-controlled elimination of underwater oil, while the superhydrophobic character of the functionalized PU sponge permitted efficient separation of oil/water mixtures and demulsification of toluene/water emulsions. Moreover, the HDPE coating not only firmly immobilized the magnetic particles, but also contributed to the excellent stability of the composite sponge which withstood acid, base, salts, seawater or temperature variation from −20 °C to 105 °C. In addition, the composite material maintained its oil adsorption ability over 10 cycles. The ease of fabrication of the magnetic super wetting 3D material sponge along with its durability and reusability makes it an interesting material with potential for practical applications.

Safety evaluation of different acids in high-density polyethylene container loading

To reduce costs, high-purity chemical suppliers wash and reuse HDPE containers collected from users. To determine the lifetime of a container, the appearance of that container and the manufacturer's recommendations for its lifetime are generally considered. Guidelines for determining the lifetime of an HDPE container have not been clearly defined. The lack of these specifications may result in the leakage of high-purity chemicals in the storage, transportation and use of HDPE containers. To understand the effects of using high-purity chemicals (sulfuric acid (H2SO4) and nitric acid (HNO3)) on HDPE, this study revealed its effects by mechanical and thermal performance tests. According to the mechanical properties test results, the ductility and tensile strength of HDPE soaked H2SO4 and HNO3 decreased. HDPE immersed in HNO3 exhibited the lowest thermal stability by thermal performance testing. In summary, the degradation of HDPE is affected by storage conditions. For this study, HDPE only needs 60 days of immersion in HNO3, and its ductility and tensile strength will decline obviously. This study shows that when these containers are used for long-term storage of high purity chemicals, the mechanical properties (including ductility, ductility, and tensile strength) of HDPE containers tend to decrease. To decrease accidental leakage of chemicals due to aging of HDPE, comprehensive and approved regulations should be established for the loading, transport, and storage of HDPE containers.

Appropriateness Assessment of Dike Height of a Chemical Plant through Development of a Hazardous Chemical Leakage Trajectory Evaluation Module

Appropriateness Assessment of Dike Height of a Chemical Plant through Development of a Hazardous Chemical Leakage Trajectory Evaluation Module

Designing an effective mitigation system based on the physical barrier for hazardous chemical leakage accidents

An evaluation module based on the liquid discharge trajectory equation was developed to improve the safety as a result of chemical leakage accidents. An evaluation was performed on leakage based on changes in the vessel pressure and discharge height during a leakage accident involving a vertical storage tank containing 35% hydrochloric acid (HCl). In addition, areal locations of hazardous atmospheres (ALOHA) and the Phast program were used to evaluate the impact and dispersion range of the discharged hazardous chemicals. The evaluation results showed that installing the mitigation system resulted in a maximum 72.8% reduction in the damage impact range in the emergency response planning guideline (ERPG)-2 distance. It was also confirmed by the Phast analysis that the dispersion range and pattern were changed according to the presence of a dike. The dispersion range decreased by up to 40% depending on the presence of the dike. It was concluded that the dispersion range is related to the physical and chemical characteristics of hazardous chemicals.

Modeling of Ammonia Emission in the Petrochemical Industry

Background: Ammonia is a commonly used chemical in the process industries. Chemical leakage is one of the main problems threatening the staff, facilities, and the environment in the process industries. Objectives: The aim of this study was to model the emission of ammonia and its consequences in the petrochemical industry. Methods: In this study, three accident scenarios of the most probable ones were chosen, including toxic vapor cloud, jet fire, and boiling liquid expanding vapor explosion (BLEVE). Then, the scenario modeling was done using areal locations of hazardous atmospheres (ALOHA) software. Results: In the first scenario, the total released ammonia is 81,316 kg. The concentration of ammonia toxic vapor is greater than 1,100 ppm (AEGL-3 region) at a distance of 1 km, which might cause death in 60 seconds. The overpressure never exceeds 3.5 psi; thus, there is no possibility of serious injury or destruction of buildings. In the third scenario, the thermal radiation of BLEVE is greater than 10 kW/m2 at a distance of 376 m, which is potentially lethal within 60 seconds. Conclusions: One of the main risks in petrochemical companies is the leakage of ammonia. The toxicity of ammonia is the most significant threat to people. The overpressure of vapor cloud explosion does not cause serious injury or of building destruction. The thermal radiation from jet fire and fireball has no effect on the city while it may cause death to the staff within 60 seconds. Thus, safety precautions should be considered to prevent the consequences of leakage accidents.

Construction of Loss Assessment Method of Eco-service Value in Sea Area Polluted by Chemical Leakage Accidents Based on Ecological Impact Prediction Model

There is no unified and standardized method for assessing the loss of eco-service value in sea area polluted by chemical leakage accidents. In this study, an index system and a set of assessment procedures for the loss of eco-service value in chemically polluted sea areas are established, and an assessment method based on the ecological impact prediction model is constructed. The validity of this method is demonstrated by taking the northern coast of Hangzhou Bay, that is, the southern sea area of Jinshan District in Shanghai as an example. The conclusion of this study is that once the leakage accident of 2000 tons soluble toxic chemicals occurs in the sea area, 1860 ha sea areas may be affected, resulting in 1.68 billion economic losses; once the leakage accident of 5000 tons oil-insoluble toxic chemicals occurs, 34000 ha sea areas may be affected, resulting in 2.61 billion economic losses.

국내 지형, 환경특성 고려 유해화학물질 거동해석 시스템 개발

As the nature of recent disasters is diversified, enlarged, and complex, disasters caused by chemical accidents are more difficult to deal with than natural or man-made disasters in terms of scale and damage. In addition, the damage does not remain as a simple primary damage but leads to secondary and tertiary damage, which leads to long-term damage. Therefore, importance of initial response and restoration support is increasingly emphasized. In this study, we define the methodology of the detailed diffusion model based on a wind field model considering topography, environmental characteristics, and a leakage rate calculation model considering the container leakage and the pool evaporation. In other words, in this study developed a system that can provide more accurate response information in the event of hazardous chemical leakage accident.

Радиометрический контроль утечки химиопрепарата при регионарной перфузии хирургически изолированной конечности

Purpose: Modernization and evaluation of the clinical effectiveness of the technology of continuous radiometric monitoring carried out during high-dose chemotherapy of a surgically isolated limb with tumor foci.
 Material and methods: A modernized radiometric control technology for regional limb perfusion is proposed. It is based on in vivo labeling of erythrocytes with 99mTc eluate followed by continuous monitoring of the activity of labeled erythrocytes as a simulator of a chemotherapy drug over the heart region. Its distinctive features are intravenous injection of a pyrfotech slice after giving inhalation anesthesia to ensure a sufficient level of red blood cell chelation, as well as using 99mTc activity less than its minimum significant level, which allows working with an open source of ionizing radiation without violating the requirements of radiation safety regulations.
 Results: The developed technology was successfully used with 106 regional perfusion of the upper and lower extremities in patients with melanoma or sarcoma of soft tissues. In 4 cases, according to the results of radiometric control, the intervention of the surgical team was required to reduce the chemical preparation leakage that was occurring.
 Conclusion: The technology upgraded by us is characterized by ease of implementation, the ability to take timely measures to prevent or reduce the leakage of a chemotherapy drug from an isolated limb according to the results of continuous in vivo radiometric monitoring of 99mTc-labeled red blood cells over the heart, as well as low radiation load on the patient and staff.

Emergency Evacuation Plan for Hazardous Chemicals Leakage Accidents Using GIS-based Risk Analysis Techniques in South Korea.

Despite improvements in chemical safety management systems, incidents involving the release of hazardous chemicals continue to happen. In some cases, they result in the evacuation of residents. For hazardous chemical release accidents, an evacuation plan needs to be selective enough to consider both the indoor and outdoor concentrations of nearby buildings and the time in which the maximum allowable concentration may occur. In this study, a real-time risk analysis tool was developed based on the geographic information system (GIS) in order to establish the emergency response and risk communication plan for effectively assisting decision-making personnel. A selective evacuation plan was also established by a proposed assessment module considering the indoor/outdoor pollution concentration of buildings and the release duration time of chlorine gas leakage. The GIS-based simulated modules were performed based on eleven buildings of Ulsan city, located near an industrial cluster and home to a high population density. As a result of the simulated real-time risk assessment, only four buildings were affected by chlorine gas concentration according to wind direction and diffusion time. In addition, it was considered effective to establish an indoor/outdoor evacuation plan as opposed to an outdoor evacuation plan which is outside the range of the damage. Subsequently, an emergency evacuation plan was established with the concentration of a hazardous chemical according to the decision-making matrix. This study can enlighten the real-time emergency risk assessment based on GIS while effectively supporting the emergency action plans in response to the release of hazardous chemicals in clustered plants and the community.

One-at-a-time sensitivity analysis of pollutant loadings to subsurface properties for the assessment of soil and groundwater pollution potential.

Chemical leak was numerically simulated for four chemical substances: benzene (light non-aqueous phase liquid (NAPL)), tetrachloroethylene (dense NAPL), phenol (soluble in water), and pentachlorophenol (white crystalline solid) in a hypothetical subsurface leak situation using a multiphase compositional transport model. One metric ton of chemical substances was assumed to leak at a point 3.51m above the water table in a homogeneous unconfined aquifer which had the depth to water table of 7.135m, the hydraulic gradient of 0.00097, the recharge rate of 0.7mm/day, and the permeability of 2.92 × 10-10m2. For comparison, surface spill scenarios, which had a long pathway from source to the water table, were simulated. Using the model results, point-source pollutant loadings to soil and groundwater were calculated by multiplying mass, impact area, and duration above and below the water table respectively. Their sensitivity to subsurface properties (depth to water table, recharge rate, porosity, organic carbon content, decay rate, hydraulic gradient, capillary pressure, relative permeability, permeability) was analyzed, with changing each parameter within acceptable ranges. The study result showed that the pollutant loading to groundwater was more sensitive to the subsurface properties than the pollutant loading to soil. Decay rate, groundwater depth, hydraulic gradient and porosity were influential to pollutant loadings. The impact of influential parameters on pollutant loadings was nonlinear. The dominant subsurface properties of pollution loadings (e.g., decay rate, groundwater depth, hydraulic gradient, and porosity for groundwater) also affect the vulnerability, and the subsurface pollutant loadings defined in this study are dependent on chemical properties as well, which indicates that the influential hydrogeological and physicochemical parameters to pollutant loadings can be used for pollution potential assessment. The contribution of this work is the suggestion that the sensitivity of pollutant loadings can be used for pollution potential assessment. Soil and groundwater pollution potential of chemicals are discussed altogether for leak scenarios. A physics-based model is used to understand the impact of subsurface properties on the fate and transport of chemicals above and below the water table, and consequently their impact on the pollutant loading to soil and groundwater.

CFD Simulation of Chemical Gas Dispersion Under Atmospheric Boundary Conditions

Pollutant control is one of the key concerns in the design of buildings, for the sake of occupational health, safety and environment sustainability. In particular, risk analyses related to emergency leakage of chemicals from storage tanks or chemical processes have aroused increasing attentions in recent days, as well as the effectiveness of mitigation measures in order to eliminate, reduce and control the risks. In this paper, a CFD methodology with nonreactive chemical gases treated as passive scalars has been developed to simulate the gas dispersion across urban environments, subject to atmospheric boundary layer wind conditions. Special treatments to maintain the consistency in atmospheric boundary layer flow profiles, turbulence modeling and boundary conditions have also been accounted for. The proposed CFD methodology for gas dispersion has been implemented in the open source CFD code — OpenFOAM. It has been validated by modeling the gas dispersions for two urban-related test cases: the CODASC street canyon test case measured in a laboratory wind tunnel and the Mock Urban Setting Test (MUST) field experiment conducted in the desert area of Utah State. Effects of turbulent Schmidt number (Sct have been primarily addressed in this study. Statistical analyses about the discrepancies between predicted and experimental data have been carried out and statistical performance measures are used to quantify the accuracy of the proposed methodology. Simulations results from passive scalar transport equation demonstrate good agreement with experimental data, though tracer gases heavier than the atmospheric air were used in both the measurements. Furthermore, sensitivity tests also indicate that the accuracy of the simulation results is sensitive to the value of turbulent Schmidt number.

Simulation Analysis of Propylene Storage Tank leakage Based on ALOHA Software

Hazardous chemical leakage accidents occur frequently, and once it appears, it will create a great effect. If a more accurate risk assessment impact area can be made in advance, the preventions and controls will play an invaluable role. A propylene storage tank in an industrial park was taken to identify the lying accidents and the risk ranks with the method of Preliminary Risk Analysis. It was found that the propylene poisoning accident and the steam cloud explosion accident have a great threat to the surrounding. With the inputs of relevant parameters, ALOHA software was used to simulate each accident, and the propylene poisoning accident and the vapour cloud explosion accident threat areas were obtained. The simulation provides effective information for the prevention and control of leakage accidents in the propylene storage tank leaking, and provides a scientific guideline for its ordinary safety management.

Extreme Weather, Chemical Facilities, and Vulnerable Communities in the U.S. Gulf Coast: A Disastrous Combination.

Many chemical facilities are located in low‐lying coastal areas and vulnerable to damage from hurricanes, flooding, and erosion, which are increasing with climate change. Extreme weather can trigger industrial disasters, including explosions, fires, and major chemical releases, as well as chronic chemical leakage into air, water, and soil. We identified 872 highly hazardous chemical facilities within 50 miles of the hurricane‐prone U.S. Gulf Coast. Approximately 4,374,000 people, 1,717 schools, and 98 medical facilities were within 1.5 miles of these facilities. Public health risks from colocated extreme weather, chemical facilities, and vulnerable populations are potentially disastrous and growing under climate change.

One-step synthesis of a steel-polymer wool for oil-water separation and absorption

Methods for the efficient and affordable remediation of oil spills and chemical leaks are crucially needed in today’s environment. In this study, we have developed a simple, magnetic, porous material based on polydimethylsiloxane (PDMS) and steel wool (SW) that can fulfill these needs. The PDMS-SW presented here is superhydrophobic, superoleophilic, and capable of absorbing and separating oils and organic solvents from water. The material is mechanically and chemically stable, even in salty environments, and can be magnetically guided. It exhibits good selectivity, recyclability, and sorption capacity, and can quickly and continuously absorb and remove large amounts of oils and organic solutions from stationary and turbulent water. In addition, PDMS-SW’s inherently high porosity enables direct, gravity-driven oil-water separation with permeate flux as high as ~32,000 L/m2·h and separation efficiency over 99%. The solution immersion process used to prepare the material is easily scalable and requires only a single step. Thus, with its demonstrated combination of affordability, efficiency, and ease of use, PDMS-SW has the potential to meet the demands of large-area oil and chemical clean-ups.

Source localization for hazardous material release in an outdoor chemical plant via a combination of LSTM-RNN and CFD simulation

Chemical leak accidents not properly handled at the early stage can spread to major industrial disasters escalating through fire and explosion. Therefore, it is very important to develop a method that enables prompt and systematic response by identifying the location of leakage source quickly and accurately and informing on-site personnel of the probable location(s). In this study, a model that predicts the suspicious leak location(s) in real-time, using sensor data, is proposed. Feed-forward neural network and recurrent neural network with long short-term memory that learned the data gathered from the installed sensors are proposed to predict the Top-5 points in the order of highest likelihood. In order to train and verify the neural networks, the sensor data generated from computational fluid dynamics simulations for a real chemical plant are used. The model learns the inverse problem solving for accident scenarios and predicts the leak point with very high accuracy.