Study On The Vaporization Control Of LNG As Marine Fuel

With the decreasing of petroleum resource, fuel prices have continued to rise. The ship as a gas-guzzler, which consumes a lot of fuel oil every year, therefore, an alternative fuel is desiderated. With the characteristics of low-carbon, high-efficiency, high-quality, and cleanliness, liquefied natural gas (LNG) becomes the best choice of marine power fuel.However, LNG is stored up on board in liquid form with temperature of-163℃under standard atmospheric pressure, so it must be vaporized if using it as marine fuel. The vaporization problem of LNG is the one of key factors which restrict the popularization and application of LNG on board. Therefore, it is necessary to analyze and study the LNG vaporization system.This paper takes the tube vaporizer as an example to analyze the dynamic characteristics of NG temperature at the heater outlet, and the specific research methods are as follows:First of all, the heat transfer theory of LNG vaporizer was analyzed, which provided a foundation for the establishment of dynamic mathematical model. In addition, the dynamic mathematical model of LNG vaporization system was established, which expressed the dynamic characteristics of NG temperature at the heater outlet. What’s more, the simulation model of LNG vaporization system was established based on the MATLAB/Simulink software. Last but not least, the PID control unit was added in the system to control the NG temperature at the heater outlet under different loads.The results obtained through simulation with the model established are very close to the actual situation. With the PID control unit, the NG temperature at the heater outlet can be stable at the set temperature under any loads. According to the simulation results, the correctness of the model and the feasibility of the control method are verified.