Influence of Wind Deviation Angle on n-Hexane Evaporation Loss of Internal Floating-Roof Tanks

With the increasing attention to environmental protection, it is still necessary to strictly control the oil evaporation loss from the IFRT(internal floating-roof tank) to the atmosphere. Upon using n-hexane as a representative of light oil, the effects of the WDAs(wind deviation angles) on airflow distribution, the wind speed, the n-hexane vapor concentration, and the evaporation loss rate in the IFRT were investigated, and the mass transfer of the vapor-air was analyzed. The results are shown as follows: when the WDA is 0°, the vapor concentration in the gas space above the floating deck is the lowest; when the WDA is 22.5°, the oil evaporation loss rate is the largest; when the WDA is 45°, the vapor concentration is the highest, but the evaporation loss rate is the smallest. It is recommended to arrange the vent to the wind direction with an angle of 45° to reduce the evaporation loss and protect the atmospheric environment.