Experimental study on heat transfer in a model of submerged combustion vaporizer

The submerged combustion vaporizer (SCV) is widely used in the peak shaving of liquefied natural gas (LNG) supply. It is believed that SCV will have a great application prospect with the implementation of the peak-shaving policy of natural gas in China. SCV injects the flue gas after combustion directly into the water bath from its bottom, causing gas disturbance and two-phase flow in the water bath. The shell-side flow and heat transfer become unclear because of the gas disturbance. There is a lack of relevant theoretical basis in this regard. In order to master the operation mechanism of SCV, an experimental research is carried out on a SCV model which has the same structure and function as the actual small-size SCV. The shell-side, tube-side and overall heat transfer coefficients are obtained, and the influences of operation parameters on the heat transfer are investigated. The results indicate that in the range of the experimental parameters, the shell-side heat transfer coefficient is almost not affected by the frontal gas velocity and Reynolds number of the flue gas at orifices, and the average value is about 300 W/(m2·°C). Meanwhile, the higher the flow rate and pressure of the tube-side medium, the greater the overall heat transfer coefficient. In addition, it is observed that if the gas disturbance stops, the heat transfer deterioration will occur. Finally, two simple empirical correlations are developed for the overall tube-side heat transfer. This study provides support for the design and application of SCV.