Speakers
Description
Liquid natural gas (LNG) boiling process concerns majority of LNG applications because of a need of its regasification. Depending on pressure an equilibrium temperature of LNG is 112-160K. The low boiling temperature of LNG makes the vaporisation process complicated. An important risk of the regasification is related to a possibility of a solid phase formation (freezing of a heating fluid). For a range of important applications the heating fluid is water or water-glycol mixture, characterized by freezing temperature considerably higher than the boiling temperature of LNG. The solid phase formation can lead to an increase of hydraulic pressures losses, deterioration of the heat transfer or even to the destruction of a heat exchanger and any accompanying device. It motivates a need for better understanding and control of a heat transfer related to the regasification to avoid the solid phase formation. The overall heat transfer intensity is a function of: boiling regime of LNG, a wall conduction and a heating fluid convection. The most important one, from the point of view of the freezing risk, is related to the LNG boiling regime. It depends strictly on temperature difference between the boiling LNG and the heating fluid. A typical boiling curve of a liquid gas varies greatly with a temperature difference. The current work analyses a LNG regasification process in a function of a number of parameters, including the LNG boiling regime. It shows that the boiling process of LNG is a main factor of the freezing risk and need to be controlled.
