A Study on the Temperature Variation of Exhaust Gas in Four-Stroke Diesel Engine for Satisfying the Operating Conditions of Low Pressure SCR

According to the IMO (International Maritime Organization)'s MARPOL 73/78 (International convention for the prevention of pollution from ships), the IMO Tier III standard was applied to the new building ship in 2016 to reduce emissions of nitrogen oxides (NOx) contained in ship’s exhaust gas by 85% or more. Regulations on hazardous gas emissions have long been in place in all industries as well as ships. Most ships around the world are using engines that have improved performance by applying electronic control systems to high-speed and low-speed diesel engines to optimize fuel economy and emissions. Training Ship“Hannara”of Korea Maritime & Ocean University also installed L.P SCR in main engine and generator engines due to the same application of IMO's Tier III regulations. The exhaust gas temperature of the generator engine is designed to be high because the operating conditions of the L.P SCR should be 0.1% or less of the sulphur content of the fuel oil and the exhaust gas temperature at the SCR inlet for catalytic reactions should be at least 290 ℃. In addition, rapid load fluctuations in operation of the thrusters, compressor operation of air conditioning systems in summer and diesel engines operation in hot weather conditions such as Southeast Asia cause additional temperature increases in the engine system. Increased exhaust temperatures in diesel engines can increase the temperatures of various systems of the engine resulting in shorter maintenance cycles and components life time, or accidents caused by high temperatures which can have a fatal effect on the safe operation of ship. Since the turbocharger exhaust temperature of diesel engines for the generator exceeded 400 ℃ and this was close to the upper limit of the high temperature alarm of 450 ℃, the exhaust gas temperature adjustment had to be carried out. Therefore, In this study, the valve timing was adjusted by changing the angle of the camshaft and the fuel injection timing of the fuel injection pump in order to lower the exhaust gas temperature to the normal range. As a results, the exhaust temperature has dropped to the extent that the operating conditions of the L.P SCR are satisfied. It is believed that the diesel engine for the generator will be able to be operated under safer conditions and prevent accidents caused by high temperatures in the exhaust system accessories.1. 서론 1 1.1 연구배경 1 1.2 연구목적 3 2. 이론고찰 4 2.1 질소산화물 저감 기술 4 2.2 SCR의 원리 4 2.3 NOx Technical Code 5 2.4 NOx Technical File 6 2.5 NOx Emission Standards 7 2.6 과급시스템 8 3. 실험 장치 및 방법 9 3.1 실험장치 9 3.1.1 실험 엔진 9 3.1.2 실험 SCR 11 3.1.3 실험 계측기기 20 3.2 실험 방법 28 3.2.1 캠샤프트 각도 조정 28 3.2.2. 연료분사시기 조정 30 4. 실험 결과 및 고찰 34 4.1 디젤 엔진 Tuning 전 후 비교분석 34 4.1.1 디젤 엔진 터보차저 출구온도 비교 34 4.1.2 디젤 엔진 시운전 결과 비교 37 4.1.3 디젤 엔진 배기가스 온도 비교 40 4.2 디젤 엔진용 L.P SCR 시운전 결과 비교 44 5. 결론 47Maste