The Effects of Heat Transfer Properties in High Viscous Fuel on the Developed Marine Fuel Preheating System
Keywords:diesel engine, exhaust gas, heat exchanger, serpentine, waste heat
Diesel engines in maritime applications exert heat energy from combustion gases: the main engines are the prime movers of ships and vessels and use marine fuel oil as working substance while the auxiliary diesel engine serve as the electrical power generator and is dependent to diesel fuel. The marine fuel oil preheating system is a contributor for energy consumption and diesel fuel consumption of auxiliary engines. Research on waste heat recovery from exhaust gases led us to an alternative source of heat which may be applied to marine fuel oil as it enters the electrical operated preheater and purifier. The purpose of this study is to determine the heat transfer equations for fluid heat exchanger, heat transfer conduction and convection through pipes shows a mathematical derivation resulting and creating specifications, size and dimensions of a serpentine coil, conveying pipe and baffle plates. This will be done by fabricating a serpentine copper coil tube since copper has the highest thermal conductivity as compared to other tubing materials. The conveying pipe and baffles were made from 1.2 mm steel sheet because of its durability and availability in the market. Results of the conducted test and simulation have shown that 92 % heat gain from the aimed temperature. Heat transfer units are also enough to heat our marine fuel oil, a highly viscous fluid ranges from 150 – 190 Centistokes at normal temperature reducing its viscosity to 119 Centistokes at 57°C. This is the target temperature to feed the fluid through a purifier and a back-up for the costly electrically operated fuel oil pre-heater. Other researchers are focusing on diesel fuel pre-heating, water heating and engine performance as they utilize the exhaust gas. The research applies for waste heat utilization, exhaust gas heat recovery, heat of combustion, thermal power and heat generation.