Design and Study of Floating Roofs for Oil Storage Tanks

Floating roofs are widely used to store petroleum products with high volatility. This is to prevent the product loss and to ensure safe environment around the storage tanks. However, small number of researches were accomplished. These researches aim at study the design of the floating roof and the associated risks that it faces during operation. In an effort to compensate the lack of knowledge for this issue and to investigate the behavior of the floating roof during operation, this paper studies the design of deck plate and roof pontoons of the floating roof with especial features. In this research and in order to study deck plate design, a comparative work was performed of the stress and deflection analyses of deck plate for the floating roofs under the load of accumulated rainfall. Five different loads were applied on the deck plate by using three different analysis methods to study the deflection and stresses. The results show that the nonlinear finite element analysis is the most accurate and applicable one to be used in the design of the floating roof deck, since it simulates the exact loading cases that happen in reality. However, using Roark's Formulas gives higher results but it can be used as a reliable and fast method in the analysis of the deck plate. To study roof pontoons design, a buoyancy analysis of the floating roof was established with punctured pontoons. In this study, three cases were applied to analyze the buoyancy of the floating roof in each case. The obeyed methodology of this study is by calculating the center of gravity and moment of inertia of the floating roof in each case. Then, to determine the submergence height due to weight and tilt and ensure that the floating roof will keep floating under each case. The results show that the floating roof will remain floating after the puncture of two adjacent pontoons and deck plate according to the design of the physical model; but it will sink if the number of punctured pontoons is increased to three.