Dynamic pressure control and GA-based PID optimization study of fuel supply system for methanol-fueled ships

Abstract

The search for clean alternative fuels to replace conventional high-emission marine fuels is a pressing issue in the context of carbon neutrality. Methanol, owing to its ability to be stored at ambient temperatures, is considered one of the promising substitutes for traditional fuels. The methanol fuel supply system plays a crucial role in regulating the parameters of methanol supply at the engine inlet, ensuring efficient and stable engine operation. This study investigates the dynamic pressure response of a methanol fuel supply system under engine load variations and disturbances of valve switching by examining its pressure control performance through experiments and simulations. A scaled-down experimental prototype of the methanol fuel supply system was constructed to test proportional–integral–derivative (PID) controller performance for pressure regulation under engine loads ranging from 0% to 100%. On the basis of prototype test parameters, a dynamic model of the methanol fuel supply system is developed, and four different main operating conditions are simulated. To improve the pressure control performance, process simulation software and genetic algorithms are combined to optimize PID parameters under different operating conditions (normal operation, emergency operation, load step, and emergency shutdown) of the methanol fuel supply system, using the proportional and integral gains as variables to be optimized. The results shows that the optimized PID controller reduces the integral values of pressure errors for the four simulated operating conditions by 90.19%, 88.94%, 72.14%, and 39.8%, respectively, and the pressure fluctuations of the system are significantly reduced under disturbances.