Numerical Simulation And Effective Utilizition Rate Study Of Steam Coil Heating Process In Crude Oil Floating Roof Tank

The operation scheme of oil storage tank is established according to the storage medium in tank, tank structure and production requirements. The oil storage temperature is usually determined based on oil property and its storage, transportation and other operation requirements. For oil product which has high viscosity and high pour point, the lowest storage temperature requirement is always needed for long term storage. In order to reduce its viscosity and improve fluidity, the heating of oil product in storage tank is needed,given that the minimum temperature can not be reached when oil product is transported.Meanwhile, a variety of insulation measures should be used to ensure the safe operation of storage tank. During establishment progress of heating scheme, the heating temperature and heating load should be determined, thus the accurate temperature distribution of oil in storage tank is needed. A complete research on the temperature field character of oil product in storage tank can provide credible basis for storage tank operation schemes,including storage tank heating scheme, thus ensuring the safe and high efficiency operation of oil tank. According to the heat transfer ways and characteristics of floating roof tanks,the stepwise tentative calculation was used to calculate the heat transfer coefficient of the roof, wall and bottom of the tank in this paper, thus setting up the theoretical heat transfer model of large crude oil tank. Heat transfer coefficient obtained by stepwise tentative calculation is plugged into the unsteady discretization equation of tank boundary node and inner heat source node with the method of interpolation, in order to analyse the change law of oil temperature and boundary temperature in tank with different impact factors. The effective utilizition rate of tank is obtained by calculating the heat released by steam coil and the heat absorbed by oil in the safe heating process of crude oil storage tank. And the change law of effective utilizition rate under different oil tank level, ambient temperature and stop heating temperature is studied, using different heat vapor pressure.