Thermal performance analysis and the operation method with low temperature seawater of super open rack vaporizer for liquefied natural gas

摘要

Super open rack vaporizer (SuperORV) is a type of liquefied natural gas (LNG) vaporizer which utilizes the sensible heat of seawater. Because of its compact structure and low operating cost, SuperORV is more and more prevalent among the world's LNG receiving stations. In this paper, a heat transfer model of a tube of SuperORV is established, and the model is validated by operation data. The profiles of the natural gas (NG) temperature and the heat transfer coefficient along the tube under the design condition are calculated and analyzed. The NG outlet temperature and the length of ice formed on the outside wall of the tube are analyzed to evaluate the thermal performance under off-design conditions. Besides, the operation method of SuperORV with low temperature seawater is discussed. It is found that the reduction of the LNG mass flow rate is an efficient method for the operation of SuperORV with cold seawater. The capacity of the vaporizer with various seawater temperatures is analyzed, and the calculation shows that the SuperORV can work with 2 degrees C seawater if the LNG mass flow rate is reduced to 46% of the design value.