The Experts below are selected from a list of 63 Experts worldwide ranked by ideXlab platform
Daphne Pantousa - One of the best experts on this subject based on the ideXlab platform.
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Numerical study on thermal buckling of empty thin-walled steel Tanks under multiple pool-fire scenarios
Thin-walled Structures, 2018Co-Authors: Daphne PantousaAbstract:Abstract Fire incidents at fuel storage tank farms are high risk incidents due to the fact that can result in severe socio-economic losses, injuries, deaths and have a serious environmental impact. In the case of a tank fire, there is a serious possibility that the fire will spread to adjacent Tanks. The research activity in this area is mainly focused on the prediction of the heat transfer characteristics of pool fires, the thermal response of neighbouring Tanks (or target Tanks) and the potential of fire spreading. On the contrary, the research for the structural integrity of Tanks involved in pool fire scenarios is limited. This paper aims to study the thermal buckling behaviour of Fixed-Roof Tanks in the case of pool fire scenarios, considering one or more burning Tanks. To this end, different scenarios are examined, aiming to study the key factors (the burning fuel, the wind, the separation distance between Tanks and the size of the burning Tanks) that may affect the thermal buckling response of the target Tanks. Semi-empirical models, available in the literature, are used for the calculation of the characteristics of flames that arise from burning Tanks. Then, the problem is solved numerically, through the Finite Element Method. The heat transfer from the burning Tanks to the target tank is treated through the open cavity option, and the response of the target tank is predicted in the same thermo-mechanical analysis. The basic objective is the investigation of the inherent fire resistance of thin-walled Tanks and to predict their failure.
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Thermal buckling behaviour of unstiffened and stiffened Fixed-Roof Tanks under non-uniform heating
Journal of Constructional Steel Research, 2018Co-Authors: Daphne Pantousa, Konstantinos Tzaros, Maria-alexandra KefakiAbstract:Abstract The problem addressed in this paper is the thermal buckling behaviour of thin-walled steel cylindrical Fixed-Roof Tanks under non-uniform loading, induced by an adjacent tank. This specific type of thermal loading can be triggered by a neighboring tank fire where heat is transferred mainly through radiation. Since the calculation of the temperature field of the heated tank lies in other scientific fields (e.g. Computational Fluid Dynamics), a thermal pattern, proposed in literature, is used for the simulation of the fire-induced load and the investigation of the structural response of the tank due to heating. The study is conducted numerically through the Finite Element method, using coupled thermo-mechanical analysis. The general purpose Finite Element code MSC Marc, is used for the simulation. Three-dimensional models are developed using shell elements. Firstly, a detailed study of the failure mechanisms that take place in case of non-uniform loading is carried out. Furthermore, Tanks with different geometries are studied. The main objective is the calculation of the critical temperature i.e. the temperature where the failure appears and the determination of the failure modes. Finally, a parametric study is conducted for the evaluation of the effectiveness of stiffening methods that are commonly used at ambient temperature design (stiffeners and stepwise wall thickness), in the case of the non-uniform heating load. In this study, the heated Tanks are considered to be empty, which is the most severe scenario, for their structural integrity.
Chi-min Shu - One of the best experts on this subject based on the ideXlab platform.
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Static and dynamic flame model effects on thermal buckling: Fixed-Roof Tanks adjacent to an ethanol pool-fire
Process Safety and Environmental Protection, 2019Co-Authors: Juncheng Jiang, Qingwu Zhang, Zhirong Wang, Liu Haisen, Chi-min ShuAbstract:Abstract Storage tank fires (such as pool-fires) often occur in the petrochemical tank farms. Flame pulsation is an important characteristic of the turbulent flames observed in pool-fires. Current cylindrical solid flame models inadequately predict the thermal radiation of pool-fires because of the ignorance of the flame pulsation effect. In this study, the thermal buckling behavior and fire resistance of a Fixed-Roof Q345 steel tank with a stepped thickness exposed to a neighboring ethanol pool-fire based on the flame pulsation model is numerically investigated. The influence of smoke generated by the combustion process which can reduce thermal radiation fluxes is taken into account. Geometric and material nonlinearity which considers nonlinear strain-displacement and stress-strain relation respectively is used on finite element analysis. Results show that the thermal buckling mode of the cylindrical tank wall is elastic buckling, and the thermal buckling behavior is non-linear. The fire resistance of the Fixed-Roof steel tank increases significantly as the vertical fire location increases, and the fire resistance decreases with the burning tank diameter increasing. Moreover, the fire resistance of the Fixed-Roof steel tank for a cylinder-cone combined flame based on the flame pulsation model is larger than that for a cylindrical flame. The study can be used to optimize the steel structure design of oil Tanks for resisting pool-fires, and thus reduce the loss caused by fire accidents in tank farms.
Denise Housley - One of the best experts on this subject based on the ideXlab platform.
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Carbon Bed Fires and the Use of Carbon Canisters for Air Emissions Control on Fixed-Roof Tanks.
Journal of The Air & Waste Management Association, 2001Co-Authors: Robert A. Zerbonia, Cybele M. Brockmann, Paul R. Peterson, Denise HousleyAbstract:Fixed-Roof Tanks are used extensively at manufacturing, waste management, and other facilities to store or process liquids containing volatile organic compounds. Federal and state air standards require the control of organic air emissions from many of these Tanks. A common practice used for some Fixed-Roof Tanks that are required to use controls is to vent the tank through an activated carbon canister. When organic vapors are adsorbed on activated carbon, heat is released. Under certain conditions, the temperature of the carbon bed can increase to a level at which the carbon or organic vapors spontaneously ignite, starting a fire in the carbon bed. Bed fires in carbon canisters are not uncommon and can present a significant safety hazard at facilities if proper safety measures are not implemented. This article discusses how carbon adsorber bed fires occur and presents general guidance on safety measures for carbon canisters installed on Fixed-Roof Tanks to reduce the likelihood of a carbon bed fire and to minimize the impact in the event of a fire.
Rebh Souilmi - One of the best experts on this subject based on the ideXlab platform.
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Study and design of Fixed Roof tank using ANSYS 14.5 and STAAD PRO
2015Co-Authors: Nourhaine Yousfi, Rebh SouilmiAbstract:Fixed Roof Tanks are widely used in the petroleum and chemical industries.Engineer or tank designer who do the preliminary and detail design are normally not familiar. Their designs are basically based on the code and standard requirements and basic theory from reference book. There is limited procedure and rules in design the Fixed Roof, these had resulted lots of Fixed Roof failure in the industry It is essential for the engineers or tank designer to know how and what effects each interdiscipline’s design would have on one’s tank that affected the tank integrity, and taking all these consideration into his design, which shows the importance of the structural design , Structural design is the methodical investigation of the stability, strength and rigidity of structures. The basic objective in structural analysis and design is to produce a structure capable of resisting all applied loads without failure during its intended life.
Msafiri M. Jackson - One of the best experts on this subject based on the ideXlab platform.
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Organic Liquids Storage Tanks Volatile Organic Compounds (VOCS) Emissions Dispersion and Risk Assessment in Developing Countries: The Case of Dar-Es-Salaam City, Tanzania
Environmental Monitoring and Assessment, 2006Co-Authors: Msafiri M. JacksonAbstract:The emission estimation of nine volatile organic compounds (VOCs) from eight organic liquids storage Tanks companies in Dar-es-Salaam City Tanzania has been done by using US EPA standard regulatory storage Tanks emission model (Tanks 4.9b). Total VOCs atmospheric emission has been established to be 853.20 metric tones/yr. It has been established further that petrol storage Tanks contribute about 87% of total VOCs emitted, while Tanks for other refined products and crude oil were emitting 10% and 3% of VOCs respectively. Of the eight sources (companies), the highest emission value from a single source was 233,222.94 kg/yr and the lowest single source emission value was 6881.87 kg/yr. The total VOCs emissions estimated for each of the eight sources were found to be higher than the standard level of 40,000 kg/yr per source for minor source according to US EPA except for two sources, which were emitting VOCs below the standard level. The annual emissions per single source for each of the VOCs were found to be below the US EPA emissions standard which is 2,000~kg/yr in all companies except the emission of hexane from company F1 which was slightly higher than the standard. The type of Tanks used seems to significantly influence the emission rate. Vertical Fixed Roof Tanks (VFRT) emit a lot more than externally floating Roof Tanks (EFRT) and internally floating Roof Tanks (IFRT). The use of IFRT and EFRT should be encouraged especially for storage of petrol which had highest atmospheric emission contribution. Model predicted atmospheric emissions are less than annual losses measured by companies in all the eight sources. It is possible that there are other routes for losses beside atmospheric emissions. It is therefore important that waste reduction efforts in these companies are directed not only to reducing atmospheric emissions, but also prevention of the spillage and leakage of stored liquid and curbing of the frequently reported illegal siphoning of stored products. Emission rates for benzene, toluene, and xylene were used as input to CALPUFF air dispersion model for the calculation of spatial downwind concentrations from area sources. By using global positioning system (GPS) and geographical information system (GIS) the spatial benzene concentration contributed by organic liquid storage Tanks has been mapped for Dar-es-Salaam City. Highest concentrations for all the three toxic pollutants were observed at Kigamboni area, possibly because the area is located at the wind prevailing direction from the locations of the storage Tanks. The model predicted concentrations downwind from the sources were below tolerable concentrations by WHO and US-OSHA. The highest 24 hrs averaging time benzene concentration was used for risk assessment in order to determine maximum carcinogenic risk amongst the population exposed at downwind. Established risk for adult and children at 2.9×10^-3 and 1.9×10^-3 respectively, are higher than the acceptable US-EPA risk of 1×10^-6. It is very likely that the actual VOCs concentrations in some urban areas in Tanzania including Dar-es-Salaam City are much higher than the levels reported in this study when other sources such as petrol stations and motor vehicles on the roads are considered. Tanzania Government therefore need to put in place: an air quality policy and legislation, establish air quality guidelines and acquire facilities which will enable the implementation of air quality monitoring and management programmes.