Thermal performance analysis and optimization design for LNG submerged combustion vaporizer

Submerged combustion vaporizer (SCV) is an efficient and energy-saving liquefied natural gas (LNG) heat exchange facility, which is developed by multiphase flow heat transfer combined with supercritical fluid heat transfer technology. This paper adopted the computational fluid dynamics (CFD) approach to investigate thermal performance of a real-life SCV with the designed handling capacity of 202 t/h. The numerical results and monitoring industrial data were in good agreement, indicting the feasibility of present method. Results displayed that two typical physical processes, namely, hot flue gas and water flowing across stagger tube bundle wall and supercritical LNG gasification, occurred inside the SCV system. The shell-side heat transfer capacity was mainly affected by the initial water level and volume rate of flue gas. Higher inlet LNG velocity could effectively enhance local tube-side heat transfer coefficient, and the maximum value may depend on the inlet LNG pressure. Furthermore, the Han models could be used to predict the overall thermal performance of SCV with a higher accuracy. Eventually, an optimization design method for SCV system was provided.