Discharge and atmospheric dispersion modelling in case of hazardous material releases

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.

FORMATION OF MATHEMATICAL APPARATUS OF METHODS OF FIRE AND EXPLOSION SAFETY CONTROL OF LANDFILL

The authors analyze the fire and explosion hazards of solid waste disposal facilities, taking into account current trends in the introduction of biogas (methane) collection and utilization systems. Methane is considered an alternative energy source for power plants. The authors determined the initial and limiting conditions of the mathematical apparatus of the method of combating fire and explosion hazards of solid waste disposal facilities based on the results of analysis and synthesis of factors of occurrence and spread of man-caused danger, existing mathematical models, and methods of counteracting man-caused danger. This is the basis for the further development of appropriate emergency response techniques. During the analysis, the authors found that humidity, the temperature of the landfill (household waste), the presence of sufficient oxygen at some point in time initiate the formation of explosive concentrations of methane in the array and contribute to the spread of hazards in landfills or dumps. The specific weight of the organic component, the value of the density of the array, the height of the landfill affect the process of counteracting the danger, namely the prevention of dangerous events and prevention of emergency from the object to the highest level of distribution (local level), primarily in the first group priorities, such as the number of victims and injured civilians and specialists of the units of the State Emergency Service of Ukraine. The team of authors has defined a system of equations of connection of the existence of the mathematical device taking into account initial and boundary conditions. A system of communication equations is determined taking into account the initial and boundary conditions of the mathematical apparatus, which allows to further develop a control algorithm for emergency response related to fire and explosion hazardous landfills close to settlements.

DEVELOPMENT OF THE BASIS OF THE METHOD OF CONTROL OF THE EMERGENCY SITUATION RELATED TO FIRE AND EXPLOSION SAFETY OF LANDFILL

It is established that today there is no effective mathematical apparatus that adequately describes the process of preventing a dangerous event and preventing an emergency related to fire and explosion of solid waste disposal facilities close to settlements. The initial and boundary conditions of the existence of the mathematical apparatus are determined, which is the basis for the development of methods of counteracting the emergency. Humidity, the temperature of the landfill, the presence of oxygen at a certain point in time are factors that initiate the danger. The specific weight of the organic component, the value of the density of the array, the height of waste disposal affect the process of counteracting the danger.

Modeling of Tunnel Concrete Lining under Fire and Explosion Damage

This paper presents studies that focus on fire and explosion-induced damage of tunnel structures by employing the Discrete Element Method (DEM). By assuming a two-dimensional aggregate distribution and reconstructing the digital representation of the experimental concrete blocks, a numerical model of the tunnel lining concrete was established in the PFC2D program. The temperature distribution and the shock wave pressure at the surface of the tunnel lining were obtained by using Fluent and LS-Dyna separately; the final damage simulation of concrete section under different conditions was carried out in PFC2D. The results showed that PFC2D cooperatively provided more accurate and effective modeling and visualization of impact damage of concrete blocks. The visualizations of damage indicated the degree of damage more clearly and more intuitively. These findings also provide a potential method for further study of the damage assessment for entire tunnel lining structures.

Fire and Explosion Hazards Due to Medical Oxygen Handling During Coronavirus Pandemic

With the continued outbreak of the coronavirus and the increase in the need for medical oxygen, it became necessary to take all measures for the safe handling of gas. Oxygen is very reactive and behaves differently to air, compressed air, nitrogen and other inert gases. Medical oxygen, at high pressure, from a cylinder, can react violently with hydrocarbons such as oil and grease which may be used mistakenly in cylinder valve or regulator. The oxidation products are a potentially explosive hydroperoxide. Nearly all materials including rubber, textiles, and metals will burn vigorously in the presence of oxygen. Atmospheric air contains nitrogen 78%, oxygen about 21% and with 1% remaining including a variety of other gases like carbon dioxide and argon. Even a small increase in the oxygen level in the air to about 24% can create a dangerous situation. It becomes easier to start a fire, which will then burn hotter and more fiercely than in atmospheric air and may be impossible to put the fire out. Increase the concentration of oxygen due to leaking valve or hose in a poorly ventilated room or in confined space can quickly create a dangerous level.

The Fire and Explosion Hazard of Coloured Powders Used during the Holi Festival

During the world-famous Holi festival, people throw and smear each other with a colored powder (Holi color, Holi powder, Gulal powder). Until now, adverse health and environmental effects (skin and eye irritation, air pollution, and respiratory problems) have been described in the available literature. However, the literature lacks data on the flammable and explosive properties of these powders during mass events, despite the fact that burns, fires, and explosions during the Holi festival have taken place many times. The aim of the article is to present the fire and explosion parameters of three currently used Holi dust and cornflour dust types as reference dust. The minimum ignition temperature of the dust layer and dust cloud, the maximum explosion pressure and its maximum rate of growth over time, the lower explosion limit, the limit of oxygen concentration, and the minimum ignition energy were determined. Tests confirmed that the currently available Holi powders should be classified as flammable dusts and low-explosive dusts. The likelihood of a fire or explosion during mass incidents involving a Holi dust-air mixture is high.

How to Determine the Dangerous Potential of Accidents to Domino Effect Detonation in a Hydrocarbon Processing Area?

The crude oil industry has been developed in recent decades due to the uses of this product, as well as its derivatives. One of the worst consequences phenomena that can occur in the process industry is the called domino effect. The domino effect or cascade effect occurs when an initiating event, such as a pool of fire or a vapor cloud explosion, causes a new number of accidents. Moreover, due to the importance of avoiding this phenomenon, the European Commission considers the domino effect analysis as mandatory for industrial facilities. There are methodologies in the specialized literature focused on quantifying the existing risks in the storage and processing of hydrocarbons. However, there is a tendency to develop new procedures that increase the risk perception of these accidents. In addition, it is necessary to develop a method that allows visualizing clearly and concisely the dangerous potential of fire and explosion accidents for the occurrence of the domino effect. Precisely, this research aims to predict the dangerous potential of fire and explosion accidents for the occurrence of the domino effect. For this purpose, a methodology consisting of three fundamental stages is developed. Finally, hydrocarbon storage and processing area is selected to apply the proposed methodology. Overall, the development of graphs that summarize information and show the dangerous potential regarding the escalation of fire and explosion accidents is vital in risk analysis. For the case study, the effectiveness of the same was demonstrated, since after its realization it was possible to increase the risk awareness of workers, technicians, and managers of the area taken as a case study.