Analysis of Main Diesel Engine Exhaust Gas Energy Utilization to Drive Turbochargers on MV Tonasa Line XVI

Abstract

Energy efficiency in the maritime sector has become a primary focus amidst the tightening of international regulations regarding greenhouse gas emissions. This study aims to analyze the amount of fuel heat energy lost with exhaust gas in the marine diesel engine of MV Tonasa Line XVI and to evaluate the effectiveness of using a turbocharger to recover a portion of this energy. The research methodology employed is experimental observation across various engine load variations, specifically 50%, 75%, and 100% of the Maximum Continuous Rating (MCR). Operational parameter data—such as exhaust gas temperatures before and after the turbine, scavenge air pressure, and specific fuel consumption—were collected directly from the ship's monitoring system. The results show that at 50% load, the exhaust gas temperature reaches 340°C before entering the turbocharger and drops to 270°C after passing through the turbine, with a system efficiency of 63.1%. Increasing the load to 75% raises the exhaust gas temperature to 390°C with an efficiency of 71.0%. At full load (100%), the exhaust gas temperature peaks at 440°C with an effective thermal efficiency of 72.4%. The study's findings indicate that the use of a turbocharger can reduce specific fuel consumption (SFC) from 230.7 g/kWh at low load to 221.1 g/kWh at full load. This proves that the turbocharger plays a vital role in converting heat energy that would otherwise be wasted into mechanical energy to increase combustion air pressure, thereby supporting improved engine performance and compliance with Energy Efficiency Existing Ship Index (EEXI) standards. In conclusion, this study recommends the use of additional waste heat recovery systems, such as an economizer, to optimize the remaining exhaust gas energy, which still exceeds 350°C at high loads.