A Study on Prismatic Pressure Vessel Type of LNG Fuel Tank for LNG Fuelled Ship

This study focuses on the necessity and the feasibility of LNG fuelled ships by analyzing industrial trends driven by environmental regulations on air-polluting exhausts from marine engines. Design and arrangement of an LNG fuel tank is critical to build LNG fuelled ships since an LNG fuel tank is more voluminous and costly than the case of the corresponding HFO tank. Furthermore, designing the tank to meet safety regulations required by IGF Code is difficult and sometimes requires development of new shape of a ship, resulting in a negative impact on cargo spaces. Recently, about 85 ships are using LNG as fuel, and most of them have adopted “Type C Independent Tank – Cylindrical Type”. It is difficult to make a proper arrangement in installing this type of tank. Hence, it might be a major challenge when the size of the tank should be increased significantly for long distance voyage. Compared with other ships, tankers have enough deck space to arrange an LNG fuel tank on. For container ships, however, position of the tank highly affects cargo capacity as cargoes are stored on deck and inside hull. Bulk carriers are faced with the same problem as container ships are due to their hatch covers and deck facilities. Bulk carriers account for the largest share of total ships in number. It is estimated that 20~30% of small and mid-scale bulk carriers will use LNG as fuel. Until now, no bulk carriers have adopted LNG as fuel. Only two cement carriers are sailing on LNG though these are special purpose vessels with special ship shape. Therefore, on the premise that cargo loss caused by the LNG fuel tank should be minimized, this thesis studies the stability and optimal arrangement of LNG fuel tank by comparing and analyzing between a cylindrical pressure tank and a prismatic pressure tank (called the “Lattice Pressure Vessel”) on the basis of standard design of a 50k bulk carrier.Contents List of Figures iii List of Tables v Abstract vi Nomenclature viii 제 1 장 서 론 1 1.1 연구 배경 1 1.2 연구 목적 2 1.3 문헌 조사 3 제 2 장 환경법 규제 트렌드 및 관련 기술 분석 9 2.1 선박 배기 오염물질 9 2.2 환경법 규제 트렌드 분석 10 2.3 환경법 규제 대응 기술 14 2.4 LNG연료 추진선 산업 동향 및 전망 15 2.5 선종별 LNG 연료추진선 탱크 배치 분석 17 2.6 LNG 연료저장탱크에 대한 기술 22 제 3 장 LNG 연료추진 50K 벌크선의 격자형 압력탱크(LPV) 설계 30 3.1 연구 목적 선박의 기본 제원 30 3.1.1 선종 및 항로 선정 배경 30 3.1.2 메인 엔진 선정 32 3.1.3 연료탱크 타입 및 용적(Volume) 34 3.2 격자형 압력 용기 설계 35 3.2.1 기술적 특성 35 3.2.2 격자형 압력 용기 설계 규정 36 3.2.3 기본 공식 38 3.2.4 탱크 설계 40 3.2.5 탱크 설계 도면 43 제 4 장 결과 및 고찰 45 4.1 실린더형 탱크와 격자형 탱크의 기술비교 45 4.1.1 부피 효율 및 무게중심 고찰 45 4.1.2 설계 하중(Design load) 48 4.1.3 BOG와 롤 오버(Roll over) 49 4.2 LNG연료추진선의 탱크 최적배치 시 고려사항 53 4.3 50k LNG 연료추진 벌크선의 탱크 최적 배치 61 4.3.1 LNG 탱크 배치 61 4.3.2 부피 효율성과 설치 공간 64 제 5 장 결 론 68 제 6 장 참고 문헌 69Maste