Experimental study on heating type pressurization of liquid applicable to LNG fueled shipping

The present experimental study investigates the pressurization effect in a fluid storage tank injected with superheated vapor. The pressurizing system re-injects high-temperature forced boil-off gas (BOG), which is emitted after heating a portion of liquid with an external heater connected to the liquid storage tank, to pressurize the liquid. The experimental equipment comprises a vertical-type pressurizing tank having a volume of 8.2 liter and a mini-vaporizer that utilizes the heater. NOVEC 649 refrigerant was used. A mathematical formulation, which can effectively predict pressure rise by considering the material and energy transfer at the interface, was suggested. The experimental results indicated that the pressurizing time reduces as the initial liquid filling ratio and heat input rate increase. It was found that the actual time required to reach the target pressure can be reduced by up to approximately 1/3 the time calculated from the homogeneous model. Without considering the heat transfer via the interface, the model results of pressure rise is approximately 10% higher than the experimental value.