Risk analysis of LPG tanks at the wildland-urban interface

In areas of wildland-urban interface (WUI), especially residential developments, it is very common to see liquefied petroleum gas (LPG) tanks, particularly with a higher ratio of propane, in surface installations serving homes. The most common tanks are between 1 and 5 m3 of capacity, but smaller ones of less than 1 m3 are more frequent. In case of accident, installations may be subject to fires and explosions, especially in those circumstances where legal and normative requirements allow very close exposure to flames from vegetable fuel near LPG tanks. In this project, it is intended to do a comprehensive diagnosis of the problem, addressing the compilation of information on real risk scenarios in historical fires. First, a preliminary presentation of the properties and characteristics of liquefied petroleum gas will be exposed. Its physical and chemical properties, production methodology, pressure and temperature diagrams and important considerations will be defined when using this type of substances in a storage tank of a certain volume. Next, a review of the situation of the existence of LPG tanks in the urban forest interfaces will be exposed. In this case, the main accidents caused by problems with the storage of LPG will be analyzed taking into account the relevance of BLEVE events in this type of incidents. To do this, the main scenarios that could take place in the event of a fire will be presented. Next, the existing legislation on the storage of LPG in these environments in some Mediterranean countries will be studied. In order to develop a comprehensive analysis, the main safety measures and distances will be considered, as well as the awareness of the possibility of vegetation material in the vicinity of LPG storage tanks, which is the main problem that will arise in a possible BLEVE scenario in case of fire. To finalize and facilitate understanding, a comparative table will be included with the aim of visualizing the main advantages and legislative deficiencies between the different countries. Following, the state of the art in terms of modelling LPG accidents at the WUI will be reviewed. Trying to simulate and predict this type of scenarios, it will see the models normally chosen to obtain the tolerable values selected and the answers obtained in each case. Finally, several fire scenarios will be simulated by means of a CFD tool (FDS, Fire Dynamics Simulator). In these simulations, the wind velocity and the distance of the combustible vegetal mass to the tank will be controlled in a WUI fire in which there is a tank of fixed dimensions. The temperature and the heat flow in each of the scenarios will be obtained, and the differences among the location of the sensors and the characteristics of the scenario will be analyzed. As a conclusion, it has been observed that there is a great amount of variables that are not contemplated by the regulatory organisms and that the existing legislation does not guarantee the safety of the population in this type of environment. From the simulations results, variables as temperature should be studied for further characterizations

DESIGN AND DEVELOPMENT OF A SMART ADVISORY SYSTEM FOR HAZARDOUS MATERIALS TRANSPORTATION RISK ANALYSIS VIA QUANTITATIVE APPROACHES

Safe transportation of hazardous materials is critical as it has a high potential of catastrophic accidents depending on the amount of transported product, its hazardous characteristics and the environmental conditions. Consequently, an efficient, smart and reliable intervention is essential to enhance prediction on the impacts of transportation hazards. Although various risk assessment techniques have been used in industry and regulatory bodies, they were developed for evaluating risk of hazardous materials for fixed installation cases instead of moving risk sources. This study applies the Transportation Risk Analysis (TRA), which is an extension of a well-known Quantitative Risk Analysis (QRA) technique in developing and design a Smart Advisory Systems (SAS), to determine the safest routes for transportation of hazardous materials according to Malaysia scenario

An innovative and comprehensive approach for the consequence analysis of liquid hydrogen vessel explosions

Abstract Hydrogen is one of the most suitable solutions to replace hydrocarbons in the future. Hydrogen consumption is expected to grow in the next years. Hydrogen liquefaction is one of the processes that allows for increase of hydrogen density and it is suggested when a large amount of substance must be stored or transported. Despite being a clean fuel, its chemical and physical properties often arise concerns about the safety of the hydrogen technologies. A potentially critical scenario for the liquid hydrogen (LH2) tanks is the catastrophic rupture causing a consequent boiling liquid expanding vapour explosion (BLEVE), with consequent overpressure, fragments projection and eventually a fireball. In this work, all the BLEVE consequence typologies are evaluated through theoretical and analytical models. These models are validated with the experimental results provided by the BMW care manufacturer safety tests conducted during the 1990's. After the validation, the most suitable methods are selected to perform a blind prediction study of the forthcoming LH2 BLEVE experiments of the Safe Hydrogen fuel handling and Use for Efficient Implementation (SH2IFT) project. The models drawbacks together with the uncertainties and the knowledge gap in LH2 physical explosions are highlighted. Finally, future works on the modelling activity of the LH2 BLEVE are suggested

Boiling Liquid Expanding Vapour Explosion (BLEVE) of Peroxy-fuels: Experiments and Computational Fluid Dynamics (CFD) Simulation

AbstractFire and explosion hazards associated with storage and transportation of flammable materials have been a matter of great interest in the recent times. BLEVE is a scenario that occurs when a closed fuel container is subjected to heat for a longer duration. Such events are disastrous to human beings and assets both. In the past there have been numerous studies on BLEVEs and fireballs of hydrocarbon fuels, e.g. kerosene, gasoline, LPG, LNG and others. Though, the fireballs of peroxy-fuels are not looked into detail as such. This article tries to overcome this lack of knowledge. Both, experimental investigation and CFD simulations are performed to measure and predict the fireball characteristics of a peroxy-fuel. Due to thermal decomposition in the liquid phase and active oxygen content a peroxy-fuel fireball burns at a very fast rate and emit higher thermal radiation whereas exhibits smaller diameter and elevation compared to hydrocarbons. That eventually leads to consideration of larger safety distances from them which are also verified by CFD results

Process hazard analysis of gasification process by using oil palm empty fruit bunch as feedstock

Production of hydrogen rich gas from the gasification of biomass to replace fossil fuels has become a common interest worldwide. One of the potential biomass in Malaysia to produce hydrogen rich gas is empty fruit bunch (EFB) from oil palm (Elaeis guineensis). Numerous researchers have carried out studies on hydrogen production using biomass but there are limited researches on the hazards analysis incorporated in the gasification process of EFB. This paper presents the hazards identification and risk reduction of the gasification process by using EFB as a feedstock. The research aims to incorporate safety needs to the gasification process of EFB for safe operation in the future. The process hazards analysis has been carried out on process unit namely fire burner, feeding hopper, fluidised bed reactor and cyclone. The potential hazard, possible causes, risk and consequences of the process unit were analysed. Based on the analysis, the major hazards identified in the process are overpressure and over temperature followed by the release of hydrogen gases. Safe by design is the most effective risk reduction strategy since it can eliminate the hazards from the source by having inherently safer design of the hydrogen process plant

Design and implementation of a database for QRA management

En aquest treball s’ha dut a terme una recerca bibliogràfica sobre la legislació a nivell europeu, espanyol i català aplicat als establiments afectats per la directiva SEVESO. S’ha realitzat una investigació sobre l’evolució d’aquestes normatives i els canvis que presenten entre elles, documentant quina és a informació requerida que cada establiment ha de presentar segons la seva categoria. La literatura fa referència a l’anàlisi quantitatiu de risc i l’informe de seguretat. S’ha dissenyat una base de dades per la recollida d’informació a partir d’informes de seguretat, basant la seva estructura en la taula de codificació de possibles accidents de la Generalitat de Catalunya. En aquesta base de dades s’ha introduït informació sobre la localització, l’activitat industrial, les condiciones meteorològiques, la substància involucrada, l’iniciador del possible accident greu i l’efecte final associat a aquest. S’ha realitzat un anàlisi exploratori de la base de dades en funció de la seva localització, condiciones meteorològiques, destacant la temperatura, humitat relativa, estabilitat atmosfèrica, direcció i velocitat del vent. També s’ha tingut en compte la substància present, el possible accident bàsic juntament amb les distàncies de seguretat (zona d’intervenció, zona d’alerta i zona d’efecte dominó). Addicionalment, s’ha estudiat l’impacte de cada un d’aquests factors en les distancies de seguretat. Finalment, s’ha realitzat una exploració pel reconeixement de patrons utilitzant la anàlisis de components principals i l’ajustament de la regressió per veure la relació que hi ha entre aquests factors, en funció de l’accident final, i les diferents distàncies de seguretat.En este trabajo se ha realizado una investigación bibliográfica sobre la legislación a nivel europeo, español y catalán aplicado a los establecimientos afectados por la directiva SEVESO. Se ha realizado una investigación sobre cuál es la evolución de esta normativa y los cambios que presentan entre ellas, documentando cuál es la información requerida que debe presentar cada establecimiento según su categoría. La literatura hace referencia al análisis cuantitativo de riesgo y al informe de seguridad. Se ha diseñado una base de datos para la recogida de información a partir de informes de seguridad, basando su estructura en la tabla de codificación de posibles accidentes de la Generalitat de Catalunya. En esta base de datos se ha introducido información sobre la localización, la actividad industrial, las condiciones meteorológicas, la sustancia involucrada, el iniciador del posible accidente grave y el efecto final asociado al mismo. Se ha realizado un análisis exploratorio de la base de datos en función de su localización, condiciones meteorológicas, destacando la temperatura, humedad relativa, estabilidad atmosférica, dirección y velocidad del viento. También se ha tenido en cuenta la sustancia presente, el posible accidente básico especificado junto con las distancias de seguridad (zona de intervención, zona de alerta y zona de efecto dominó). Adicionalmente, se ha estudiado el impacto de cada uno de estos factores en las distancias de seguridad. Por último, se ha realizado una exploración para el reconocimiento de patrones utilizando el análisis de componentes principales y el ajuste de regresión para ver la relación existente entre estos factores, en función del accidente final, y las diferentes distancias de seguridad.In this project, bibliographic research is carried out on the European, Spanish, and Catalan legislation applied to establishments affected by the SEVESO directive. Research on the evolution of these regulations and the modifications between them is conducted, documenting the required information that each establishment must present according to its category. The literature refers to quantitative risk analysis and safety reports. A database is designed for the collection of information from safety reports, basing its structure on the coding table of possible accidents of the Generalitat de Catalunya. Information on the location, industrial activity, meteorological conditions, substance involved, initiator of the possible major accident and the final event, are the fields introduced in the database. An exploratory analysis of the database is carried out according to its location, meteorological conditions, including temperature, relative humidity, atmospheric stability, wind direction and velocity. The substance present, the possible basic accident and final event, specified together with the safety distances (intervention zone, alert zone, and domino effect zone) are also considered. In addition, the impact of each of these factors on the safety distances is studied. Finally, an exploration via pattern recognition using principal component analysis and regression adjustment is done to investigate the existing relation between these factors, as a function of the final event, and the different safety distances

Using historic accident data to estimate the potential fatalities due to chemical hazards

Inherent safety is that which is intrinsic to a chemical plant. Chemical plants should be designed to be acceptably safe and it is better if this can be achieved through inherent safety, which cannot be compromised, rather than added-on engineered safety. The earlier that inherent safety is considered, the greater are the benefits. The aim of this project is to develop a method which can be used to assess the inherent safety of a chemical plant, by estimating the potential number of fatalities in the event of a catastrophic accident. This method is intended for use in the early phases of design when the major decisions on the chemical process are made. In the early stages, only limited information about equipment and plant layout exist as well as the reaction chemistry and the physical, chemical and toxicity properties of the chemicals involved. [Continues.