Global Journal of Researches in Engineering, E: Civil & Structural, Volume 23 Issue 2

Studies carried out by Oliveira (2020a; 2015) show that the more volatile the product stored and the larger the tank diameter, the efficiency of the internal floating roof will be better. Figure 4 illustrates the reduction in losses due to VOC emissions in tanks with and without floating roofs for alcohol and gasoline storage tanks. Floating roofs bring benefits in firefighting in the NBR 17.505e (ABNT, 2006), because by reducing VOC emissions, it also reduces the area subject to explosion risks. The use of this type of ceiling can also be applied to other specific cases, such as the reduction of contamination of products with water - biodiesel or demineralized water - however these applications still need specific studies to prove the efficiency of internal floating ceilings. Source: Adapted from Oliveira, 2020a Figure 4: Reduction of emission losses in tanks with and without floating roofs d) Environmental Criteria In order to alert the designer to environmental and not only economic efficiency for the design of storage tanks, but this study also evaluated the influence of the external painting of the tanks and the area of solar irradiation. i. Appropriate Choice of Exterior Paint The external painting of the fuel storage tank can have a big impact on the evaporative loss of stored products. According to Castilho (2018) losses can be reduced by up to 25%. According to the author, the darker the color of the paint adopted for the external painting, the greater the energy absorbed, and, consequently, the loss by evaporation of VOCs will increase. Other factors must be considered when sizing the tank, such as the volatility of the stored product and the area to be painted in the tank, since the larger the area to be painted, the greater the influence of the choice of paint to reduce losses due to evaporation. The use of light colors – white or gray – is the most suitable for fuel storage (Table 4) and the choice of these colors for painting tanks with floating roofs is relevant for reducing VOC emissions during the useful life of the tanks. It is observed that in the case of fixed roof tanks the influence is very relevant, especially for gasoline storage. For Castilho et al (2023) the use of white color in storage tanks, instead of gray, relatively common in tank parks, can represent a reduction of up to 40% in VOC emissions. However, if there is an interest in the tank absorbing greater thermal energy to keep the product warm, such as the storage of biodiesel obtained from animal tallow, the use of dark colors will reduce the need for adding heat by through internal coils, with consequent environmental gain for the tank design. © 2023 Global Journals Global Journal of Researches in Engineering ( ) E Volume XxXIII Issue II Version I 7 Year 2023 Atmospheric Storage Cylindrical Tanks: Project Optimization Considering Environmental Criteria