HEAT TRANSFER CHARACTERISTIC FOR A LARGE-SCALE DOUBLE-DECK FLOATING ROOF OIL TANK

The heat transfer characteristic for a double-deck floating roof oil tank was investigated based on the test of surface temperature and heat flow in working conditions. The profile of surface temperature on the roof generally appears an axial symmetry feature, dominated by the thickness of the roof and oil volatilization. The clapboard and truss enhance heat conduction which induces higher surface temperature in some local positions. The maximum temperature on the roof appears in the region between the weir plate and sidewall, while the lowest temperature region is the central part of the roof. Moreover, according to the profile of surface temperature, the sidewall is divided into two parts separated by the oil level. Based on the test data, nearly 70% of heat is lost through the roof, followed by the sidewall and bottom. The heat flow test reveals an approximate one-dimensional characteristic of heat transfer through the roof. The value of the equivalent conductivity of the roof is from 2.63 W/m·K to 6.05 W/m·K while the average value is 4.44 W/m·K. The test result of sidewall reveals additional thermal resistance most likely caused by the wax precipitation layer which should be noted during the heat transfer calculation.