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습식제련법을 활용한 저품위 흑연 고순도화 기술개발
No full text2차전지, IT 기기의 핵심원료인 천연흑연은 우리나라에서는 전혀 생산되지 않으며, 대부분의 수요물량을 중국에 의존하고 있다. 자원·소재 안보 강화를 위해 흑연원료물질의 부가가치 향상 기술확보가 필요하다.
본 연구에서는 천연흑연정광(탄소품위 : 90%이상, 구형도 0.8이상)의 2차전지 음극재 원료물질로서의 활용을 위해 입자표면개질을 포함한 구형화 공정 및 흑연정광 내 함유된 회분 제거를 위한 습식정제공정을 구축하고자 하였다.
구형화 공정 구축을 위해 입자 표면개질과 고속회전이 가능한 장비(NOBILTA-130, NHS-0)을 활용하여 장비 구동속도(3,000 ~ 12,000rpm)를 주 변수로하여 실험을 진행하였으며, 10,000rpm에서 구형도 0.916, 12,000rpm에서 구형도
0.936의 실험 결과를 보였고, 구형화 후 건식분급을 통해 5㎛ 이하의 미립 플레이크를 분리·제거하여 구형도는 0.947, 평균입도 16.362㎛의 2차전지 음극재 적용에 적합한 균질한 입자크기를 갖는 구상흑연을 획득하였다.
구형화 후 흑연정광 시료에 시약급 황산, 염산, 수산화나트륨을 활용하여 침출법을 통해 흑연정광 내 회분제거 실험을 실시하였으며, 탄소품위 및 불순물(회분)의거동을 확인하였다. 실험 조건은 알칼리 정제실험에서는 오토클레이브를 활용하여 시약농도(수산화나트륨 농도 : 1, 2, 3N), 반응온도(150, 200, 250℃), 반응시간(0.5, 1시간)를 변수로 두고, 광액농도 10%, 반응압력은 증기압으로 하여 실험을 진행하였다. 산 정제실험은 일반적인 침출반응기를 활용하여 시약종류(황산, 염산), 시약농도(2, 3, 4N), 반응온도(50, 70, 100℃), 반응시간(0.5, 1, 2, 3시간)을 변수로 하고, 광액농도 10%, 반응압력은 상압으로 하여 실험을 진행하였다. 알칼리 단일정제 실험결과, 3N 농도조건에서 불순물 제거율 66.0%, 탄소 품위 97.8%로 가장 좋은 결과를 보였고, 산 단일정제 실험결과, 황산 2N 농도조건에서 불순물 제거율 45.9%, 탄소품위 96.5%로 가장 높았으나, 본 연구의 목표인 99.9% 이상의 탄소 품위에는 도달하지 못해 각 단일정제법에서 도출한 최적조건을 활용해 산-알칼리 교차정제 실험을 수행하였으며, 황산-수산화나트륨 순의 교차정제 실험에서 불순물 제거율 95.9%, 탄소품위 99.7%로 기존 단일정제법보다 불순물 제거율이 최대 50%까지 상승하는 것을 확인하였으며, 99.9% 고순도 흑연제조를 위해 흑연층 내부의 불순물을순차적으로 제거하기 위해 산-알칼리 다단정제 실험을 실시하였으며, 최대 5단까지실험을 진행하였다. 실험 결과, 2~3회 정제 시 99.9~99.95%, 4~5회 정제 시 99.95~99.99%의 초고순도 정제가 가능하였고, 불순물 제거율 또한 95.2%~99.7%까지 제거되어, 산-알칼리 시약을 활용한 습식정제법으로 2차전지 음극재 원료 스펙에 부합하는 흑연원료 제조가 가능함을 알 수 있었다.1. 서 론 1
1.1 연구배경 1
1.2 흑연의 특성 3
1.3 리튬이차전지 음극재용 흑연 5
2. 이론적 배경 9
2.1 흑연 입자 구형화 기술 9
2.2 불순물 제어공정 10
3. 실험 방법 12
3.1 시료 및 시약 12
3.2 실험장비 및 진행방법 12
3.2.1 입자구형화 및 분급실험 12
3.2.2 불순물 정제 실험 13
3.2.2.1 산/알칼리 정제실험 13
3.2.2.2 연속 다단 정제실험 16
3.3 분석방법 17
4. 실험결과 20
4.1 대상시료의 특성 20
4.2 입자구형화 및 분급 실험결과 23
4.3 정제실험 결과 42
4.3.1 알칼리 단일 정제실험 결과 42
4.3.2 산 단일 정제실험 결과 44
4.3.3 산-알칼리 교차정제실험 결과 47
4.3.4 산-알칼리 다단침출실험 결과 52
5. 결 론 58Maste
Performance Analysis of Ammonia Solid Oxide Fuel Cells Integrated System with Various Designations of Waste Heat Recovery
No full textMaritime transportation, which is the primary mode of transportation, carries out more than 80% of world trade by volume. Thus, it is significantly contributing to air pollution and climate change resulting in a negative effect on human health and the environment. The International Maritime Organization (IMO) has adopted various regulations and requirements in response to this issue and limit greenhouse gas emissions (GHGs), control airborne pollutants, and protect future environment. These standards and objectives have encouraged the use of innovative technology, renewable energy, and decarbonized or low-carbon alternative fuels in global maritime shipping. Ammonia has recently gained attention as a promising marine fuel for reducing CO2 and SOx emissions, resulting in minimal climate change and green future energy. Since ammonia can be efficiently produced and stored using renewable energy sources, ammonia has become an efficient energy vector. Because it is inexpensive, portable, less flammable than other fuels, and relatively safe due to detectable odor leakage, it is a viable fuel for fuel cells.
This thesis presents studies on the possibility of using ammonia for SOFC system and the performances of direct ammonia Solid Oxide Fuel Cells (SOFC) in various waste heat recovery combined systems with application targeted for 3800 kW marine vessels. The three different designations of ammonia SOFC-waste heat recovery systems are established and proposed. The process simulation software named ASPEN-HYSYS V12.1 (AspenTech, Massachusetts, USA) are used to estimate the thermodynamic properties and operating parameters of all components.
The effectiveness of various viable waste heat recovery systems and cycles, such as gas turbine (GT), Steam Rankine Cycle (SRC), Organic Rankine Cycle (ORC), Kalina Cycle (KC), Waste heat boiler (WHB), Proton Exchange Membrane Fuel cells (PEMFC), ammonia reforming and hydrogen purification system are employed for harvesting waste heat from the exhaust gas of SOFC, has been analyzed and evaluated in terms of thermodynamic performances. The energy efficiency of designation 1,2,3 were obtained at 64.53%, 60.4% and 60.69%, respectively which are all higher than SOFC-stand-alone system. Besides, the combination of SOFC and PEMFC in proposed designation 3 is expected to overcome disadvantage of SOFC on start-up and maneuvering period of vessels.
The numerical study results of the ammonia SOFC system were compared and revealed a good agreement with reported results in the literature. The results demonstrated that employing a suitable waste heat recovery system will significantly contribute to the output power and energy, exergy efficiency of an entire integrated system.
In an effort to discover a method to further improve fuel cells power output and thermodynamic performances, this thesis also investigated the effects of operating factors that have an impact on the performance of the integrated systems such as current density of SOFC, fuel utilization factor, working fluid of organic Rankine cycles, working parameter of Steam Rankine Cycle, distribution ratio of ammonia supply to SOFC and PEMFC, and etc. The variety range of current density was set from 930 A/m2 to 1830 A/m2 to examine the response of output power and efficiencies of systems. The ORC’s working fluids also carefully examined and selected in consideration of each application characteristics. The studies in this thesis have effectively evaluated the benefits of using various viable waste heat recovery systems for the direct ammonia SOFC combined to increase the output power and thermal efficiency of system. The use of ammonia SOFC for marine vessels is also recognized as an effective method to meet the emission IMO’s regulations of emission control that limitation to be found in previous researches.Chapter 1: INTRODUCTION 1
1.1 Introduction 1
1.2 Aim and Methodology 4
1.2.1 Aim of the study 4
1.2.2. Methodology 4
1.3 Desissertation outline 5
Chapter 2: BACKGROUND AND LITERATURE REVIEW 6
2.1 Ammonia as an efficient hydrogen carrier 6
2.2 The fuel cells technologies 12
2.3 Direct ammonia SOFC 16
2.3.1. Ammonia SOFC-O system 18
2.3.2. Ammonia SOFC-H system 18
2.3.3. NOx formation 19
2.3.4. Other related issues of ammonia SOFC system 20
2.4 Indirect ammonia PEMFC 21
2.5 Waste heat recovery cycles 22
2.6 Workflow of current study 29
Chapter 3: THERMODYNAMIC MODELS 31
3.1 Thermodynamics balance equations 31
3.2 Establishing the SOFC models 33
3.3 Establishing the PEMFC models 38
3.4 Establishing models for waste heat recovery cycles 41
3.4.1. Afterburner 41
3.4.2. Gas Turbine 41
3.4.3. Air compressor 42
3.4.4. Electric generator 43
3.4.5. Heat exchangers 43
3.4.6. Kalina cycle 43
3.4.7. Steam Rankine cycle 44
3.4.8. Organic Rankine cycle 44
3.4.9. Ammonia dissociation unit 44
Chapter 4: SIMULATION MATERIALS AND ASSUMPTIONS 46
4.1 Simulation materials 46
4.2 REFPROP model 49
4.3 The Peng-Robinson equation of states 49
Chapter 5: PROPOSED DESIGNATION 1: SOFC-GT-SRC-WHB 51
5.1 Introduction 51
5.2 System Description 54
5.2.1. Designation 54
5.2.2. Operating principle 54
5.3 Equation models 56
5.4 Model verification 61
5.5 Results and discussions 62
5.6 Conclusion 73
Chapter 6 : PROPOSED DESIGNATION 2: SOFC-GT-SRC-KC-ORC 75
6.1 Introduction 75
6.2 System Description 77
6.2.1. Designation 77
6.2.2. Operating principle 79
6.3 Thermodynamic models 81
6.3.1. Model of the SOFC 81
6.3.2. Model of GT 81
6.3.3. Model of Kalina cycle 81
6.3.4. Model of SRC 82
6.3.5. Model of ORC 83
6.3.6. Exergy destruction 83
6.3.7. Total energy and exergy efficiencies 84
6.4 Model verification 85
6.5 Results and discussion 86
6.5.1. Sequential Optimization 86
6.5.2. The overall system performances 93
6.5.3. Parametric study 95
a) Effect of the current density 95
b) Influence of the ORC’s working fluids 97
6.6 Conclusions 101
Chapter 7: PROPOSED DESIGNATION SYSTEM 3: SOFC-GT-PEMFC-ORC-SRC-KC-WHB 103
7.1 Introduction 103
7.2 System Description 107
7.2.1. Designation 107
7.2.2. Operating principle 107
7.3 Thermodynamic models 111
7.4 Model verification 118
7.5 Results and Discussions 119
7.6 Conclusions 131
Chapter 8: CONCLUSIONS 134
8.1 Proposed designation 1: SOFC-GT-SRC-WHB 136
8.2 Proposed designation 2: SOFC-GT-SRC-KC-ORC 137
8.3 Proposed designation 3: SOFC-GT-PEMFC-ORC-SRC-KC-WHB 138
Reference 141Docto
선박 접안에너지를 고려한 방충재 용량 평가에 관한 연구
No full textWhen designing quay facilities in a port, the type and size of berthing ships are generally selected, and the type and capacity of bollard and fender are selected according to the port and fishing port design standards. The fender material is determined by the ship type, dead weight tonnage and berthing energy. among them, the size of the vessel affecting the vessel berthing capacity is changing with the increase in the size of the vessel and the amount of cargo. according to the Harbour and Fishery Design Criteria, both the absorbed energy and the reaction force of the fender should be considered in the safety evaluation of the fender. however, the absorbed energy of the fender is not evaluated in the current maritime traffic safety assessment. For this reason, in this study, the adequacy of the fender according to the design standards for excess ships and piers entering the main port of Ulsan Port was evaluated, and the absorbed energy and reaction force energy of the fender were compared and reviewed.
In order to analyze the excess ships entering the Ulsan main port state-owned pier, through Ulsan Port PORT-MIS, for about one year from January 1, 2020 to December 30, 2020, for ships entering Ulsan Port, the excess ships by each pier was reviewed. As a result, it was analyzed that 16 berths out of 21 berths entered port, and the rate of occurrence of ships exceeding berthing capacity was analyzed to be at least about 1.1% and at most about 45.5%.
The risk of the pier caused by the excess ships compared to the berthing capacity of the pier was measured by the impact and the likelihood of risk, respectively, and the effect on the pier was analyzed. As a result of risk assessment, 7 berths out of a total of 21 berths were evaluated as high risk berths, and 1 berth was evaluated as very high risk berths.
The berthing energy analysis is based on the risk analysis results for the Ulsan main port state-owned pier, and for piers with high risk or higher, the amount of change in berthing energy according to the change in the size of the vessel according to the Harbour and Fishery Design Criteria is calculated based on the berthing capacity of the pier. It was compared with the absorbed energy.
The berthing energy analysis of the ship was analyzed according to the kinematic method of the Harbour and Fishery Design Criteria.
For the mooring safety evaluation, based on the risk analysis results for the Ulsan main port state-owned pier, the target pier that can secure the pier drawing was selected among piers with high risk or higher, and the reaction force of the fender was evaluated for the largest incoming vessel.
Based on the results of the risk analysis on the Ulsan main port state-owned pier, the absorption energy and reaction energy of the seawall for the target pier that can secure the drawing of the pier above High Risk were compared and the need for the absorption energy of the ship not currently performed in the Maritime Safety Audit Scheme was presented.
Through this study, it is judged that the rate of port accidents can be further lowered if the appropriate amount of fender is presented during Maritime Safety Audit Scheme, and it is judged that it will be possible to suggest a way to review safety from various angles to pier designers in the future.|항만의 부두 시설물 설계는 일반적으로 접안선박의 선종 및 크기를 선정하고, 항만 및 어항 설계기준에 따라 계선주와 방충재 등의 종류 및 용량을 고려한다. 방충재는 선종, 재화중량톤수 및 접안에너지에 의해 결정된다. 이 중에서도, 선박 접안력에 미치는 선박의 규모는 선박의 대형화 및 화물 물동량의 증가에 따라 변화하고 있다. 항만 및 어항설계 기준에 따르면, 방충재의 안전성 평가는 방충재의 흡수에너지와 반력이 모두 고려되어야 한다. 하지만 현행 해상교통안전진단에서는 방충재의 흡수에너지는 평가되고 있지 않다. 이러한 이유로 본 연구에서는 울산항 본항에 입항하는 초과선박 및 부두 설계기준에 따른 방충재의 적정성을 평가하고, 더 나아가 방충재의 흡수에너지와 반력에너지를 비교 검토하였다.
울산항 본항 국유부두에 입항하는 초과선박을 분석하기 위하여 울산항 PORT-MIS를 통하여 2020년 1월 1일부터 2020년 12월 30일까지 약 1년간 울산항에 입항하는 선박을 대상으로 각 부두별 초과선박에 대하여 검토를 수행하였다. 그 결과, 21개 선석 중 16개 선석에서 접안능력을 초과하는 선박이 입항하는 것으로 분석되었으며, 부두능력을 초과하는 선박의 발생비율은 최소 약 1.1%에서 최대 약 45.5%로 입항하는 것으로 분석되었다.
부두의 접안능력 대비 초과선박으로 인하여 발생하는 부두의 Risk는 위험의 영향력(Impact)과 발생가능성(Likehood)으로 각각 측정하여 부두에 미치는 영향을 분석하였다. Risk 평가 결과 총 21개 선석 중 7개의 선석이 High Risk 선석으로 평가되었으며, 1개의 선석이 Very High Risk 선석으로 평가되었다.
접안에너지 분석은 울산항 본항 국유부두에 대한 Risk분석 결과를 바탕으로 High Risk 이상의 부두에 대하여 부두 접안능력을 기준으로 최대 입항선박 규모까지 항만 및 어항 설계기준상의 선박규모 변경에 따라 접안에너지 변화량을 방충재의 흡수에너지와 비교하였다.
선박의 접안에너지 분석은 항만 및 어항설계 기준의 운동역학적 방법에 따라 분석하였다.
계류안전성 평가는 울산항 본항 국유부두에 대한 Risk분석 결과를 바탕으로 High Risk 이상의 부두 중 부두의 도면을 확보할 수 있는 대상 부두를 선정하여 최대 입항선박을 대상으로 방충재의 반력을 평가하였다.
울산항 본항 국유부두에 대한 Risk분석 결과를 바탕으로 High Risk 이상의 부두 중 부두의 도면을 확보할 수 있는 대상 부두에 대한 방중재의 흡수에너지와 반력에너지에 대하여 비교 검토하였으며, 현 해상교통안전진단에서 수행하고 있지 않은 선박의 흡수에너지의 필요성을 제시하고자 하였다.
본 연구를 통해서, 해상교통안전진단 시 적정 방충재의 용량을 제시한다면 항만 사고의 비율을 더욱 낮출 수 있을 것으로 판단하며, 향후 부두 설계자에게도 안전성을 다각도에서 검토할 수 있는 방안을 제시할 수 있을 것으로 판단된다.1. 서 론 1
1.1 연구배경 및 목적 1
1.2 연구 방법 3
2. 울산항 입출항선의 접안능력 분석 4
2.1 울산항 입출항 선박 분석 4
2.1.1 울산항 부두 현황 분석 4
2.1.2 부두 접안능력 초과선박 비율 6
2.1.3 실제 부두 이용 최대크기급 선박 8
2.2 부두 Risk 분석 및 대상부두 선정 11
2.2.1 부두 Risk 분석 11
2.2.2 대상부두 선정 14
3. 부두별 접안에너지 분석 16
3.1 선박의 접안에너지 16
3.2 접안속도 22
3.2.1 국내 접안속도 기준 22
3.2.2 PIANC 및 국외 접안속도 기준 27
3.3 대상부두 접안에너지 분석 30
3.3.1 대상부두 방충재 흡수에너지 분석 36
3.3.2 선박 접안에너지 분석 38
3.3.3 적정 접안속도 분석 42
3.3.4 적정 접안속도 평가결과 50
4. 계류안전성 분석 52
4.1 계류안전성 분석 개요 52
4.2 계류안전성 분석 상황 모델링 53
4.2.1 수학모델 53
4.2.2 좌표계 및 부호규약 54
4.2.3 계류상황 모델링 58
4.2.4 방충재 특성 모델링 70
4.2.5 환경외력 모델링 74
4.3 대상부두 계류안전성 분석 81
4.3.1 시나리오 설정 81
4.3.2 계류안전성 분석 82
4.3.3 계류안전성 평가 결과 88
5. 결 론 89
5.1 결론 89
5.2 한계점 및 향후 과제 92
참 고 문 헌 93Maste
디젤엔진 크랭크축 피로 평가를 위한 수치 해석적 연구
No full textAccidents involving crankshaft of marine diesel engine have recently become common. Therefore, adequate fatigue assessment of the crankshaft is required to reduce the occurrence of severe accidents.
This study aims to analyze stress and deformation using actual accident cases and data, based on finite element analysis. Three-dimensional models of the crank and crankshaft were designed and developed using “Autodesk inventor.”
This study identifies vulnerable areas where stress is concentrated and proposes improvement design and factor level. Using “Ansys workbench and Autodesk Nastran,” finite element analysis was performed by “static and transient structural analyses,” which were used to determine the maximum equivalent stress and total deformation at vulnerable parts of the crankshaft.
The model was tested under static and dynamic loading conditions to determine vulnerable fatigue area, deformation, equivalent alternating stress, and damage using the fatigue tool.
To improve the accuracy of the durability fatigue limit, fatigue analysis was also performed using the physical properties of the material applied to the model ship, with the same stiffness and heat treatment (SCM440).
The simulation was conducted under the same design and similar conditions as the ship where the actual accident occurred, and excessive deformation and stress concentration were confirmed in the crank pin fillet and journal fillet parts of the crankshaft.
Structural and fatigue analysis on the additional processed design model by the fillet unit confirmed that stress and deformation in the same location were reduced.1. 서론 1
1.1 연구의 배경 및 목적 1
1.2 연구 내용 4
2. 이론적 배경 6
2.1 동력 전달 계통 6
2.1.1 동력 전달 원리 6
2.1.2 크랭크축 7
2.1.3 크랭크축에 작용하는 힘 9
2.2 피로 파괴(Fatigue fracture) 14
2.2.1 파괴 형식과 재료의 강도 14
2.2.2 피로 균열발생 매커니즘 15
2.2.3 피로 응력 15
2.2.4 S-N 곡선 19
2.3 크랭크축 피로평가 25
2.3.1 디플렉션 계측 25
2.4 유한요소해석 27
2.4.1 유한요소해석의 정의 27
2.5 선박 사례 분석 28
3. 크랭크의 변형 및 응력 평가 33
3.1 주요 설계 자료 33
3.2 해석 조건 36
3.2.1 형상 모델링 36
3.2.2 Mesh 설정 37
3.2.3 구속 조건 38
3.2.4 하중 조건 39
3.3 해석 결과 40
3.3.1 크랭크핀에 Pmax를 작용하여 크랭크축 변형량 및 안전성 분석 40
3.3.2 크랭크암 변형에 따른 응력분석 및 Nastran 활용하여 검증 41
3.3.3 Ansys를 활용하여, Pmax와 디플렉션 허용 범위와의 상관관계 분석 41
3.3.4 Nastran를 활용하여 가상 응력과 크랭크축의 응력 집중 경향성 분석 43
4. 크랭크축의 피로 안정성 평가 45
4.1 피로 파괴 해석 조건 45
4.1.1 형상 모델링 45
4.1.2 Mesh 설정 47
4.1.3 구속 및 하중 조건 47
4.2 해석 결과 49
4.2.1 동적 하중 작용 시, 크랭크축 변형 취약부 및 변형량 분석 49
4.2.2 최대 폭발 압력 작용 시, 크랭크축에 발생한 응력 분석 49
4.2.3 응력취약부 개선 후 응력 분석 51
5. 결론 53
참고문헌 55Maste
중국 항만운영자의 책임제한제도에 관한 연구
No full textMaritime transport is the main mode of international trade transport. After COVID-19 pandemic, with the implementation of strong economic stimulus plans in each country, commodity consumption is increasing, and the rapid growth of e-commerce has also stimulated the recovery of maritime trade. United Nations Conference on Trade and Development, Review of Maritime Transport 2021 (New York): United Nations Publications, 2021, p.16.
Because ports (i.e., crucial hubs that connect sea and land transportation) are a crucial component of international maritime transport, port operators are a critical research subject. Due to the rapid development of international maritime cargo transportation, port operations have exhibited significant progress and development.
Due to the rapid development of the port industry, the legislative process pertaining to China's port laws and regulations is lagging, and the provisions on the legal responsibility of port operators are insufficient; thus, the development of the port industry is hindered. Specifically, the liability limitation system of port operator is related to the amount of compensation liability they bear when facing claims, and the balance of the risks they bear and the rights they enjoy.
Moreover, with respect to whether a port operator can enjoy a limitation of liability and the basis for it, the lack of legislation has led to a wide variation in judicial decisions in China; thus, judicial uncertainty is prevalent.
In regard to the aforementioned issue, the author observed that although Korea and China, which are friendly neighbouring countries, exhibit similar provisions in their respective laws (i.e., Korean Commercial Law and Chinese Maritime Law), the legal status and liability of port operators in Korean judicial practice is not as confusing as that in the Chinese one. The Korean courts have generally recognised the legal status of the port operator as an ＂Independent Contractor＂, which provides a rational method through which the port operator's limitation of liability system can be structured.
The current era represents a crucial moment for the revision of China's Maritime Law. The 2020 Maritime Law Draft for Examination has led to considerable advancements; port operators have been introduced into the Maritime Law scope, and they can enjoy the limitation of liability, which was exclusively enjoyed by carriers. However, many shortcomings, such as the lack of clarity in the definition of the port operator concept and the lack of provisions on the circumstances in which the port operator loses the limitation of liability, exist.
This thesis focuses on the legal status and liability of port operators, and it considers the carriage of goods by sea; furthermore, it employs research methods (e.g., documentary research, comparative research, and case analysis) to classify the evolution of domestic and international legislation, and it conducts a detailed analysis of domestic and international legislation and typical cases. Based on the revision of China's Maritime Law, this thesis proposes the relevant rules of adjudication and legislative amendments from the levels of interpretation and legislative theory, respectively, and it is guided by the international law and contract law theories.
The thesis comprises five chapters, including an introduction and a conclusion.
Chapter Ⅰ Introduction. This chapter introduces the research background, research objectives, research methods, and thesis scope, and it identifies the research values, main directions, and basic thesis framework.
Chapter Ⅱ The Liability System of Port Operators and Issues under Chinese Law. This chapter delineates the concept and the basic legal provisions of the port operator (i.e., the subject of study)under Chinese law. By citing maritime law scholars, it first introduces the different definitions of the port operators concept, and it collates the legal provisions in China from 1995 to the present year. The author observes that there is no direct provision for the port operator and its liability limtation in China's contemporary law; thus this legisilation gap should be filled during the revision of the China Maritime Law . Subsequently, various cases of Chinese court decisions on the legal liability and liability limitation of port operators have been collated, which reveal that the determination of the liability of port operators in Chinese judicial practice is largely dependent on the court's identification of the legal status of the port operator in a particular case. After reviewing the relevant Chinese port operator cases, the author introduces and analyses several main opinions and notes their shortcomings and irrationality. The author argues that under the existing Chinese legal system, there is immense uncertainty as to whether the port operator enjoys the limitation of liability. The inconsistent understanding of the legal status of port operators in Chinese academia and judicial practice has led to inconsistent determinations as to whether port operators are entitled to a limitation of liability.
Chapter Ⅲ Comparative Law Study on the Port Operators and their Limitation of Liability Systems, the provisions on the port operators in the world's major countries (e.g., the United Kingdom, the United States, and Korea) and those of international conventions (e.g., the O.T.T. Convention) are reviewed. The author has collated and organised the legal provisions of different countries at different periods of time and analysed typical cases at the domestic and international levels. It was observed that most countries do not possess a uniform term for the port operator concept, and that each country exhibits its own port operator characteristics. The scope of this terminology is determined as per different national conditions, legislative purposes, and practical needs. With regard to the legal system for the limitation of liability of port operators, if the development trend of international conventions and extraterritorial laws (e.g., the Hague Rules, Visby Rules, and Rotterdam Rules) are considered, the carrier's period of responsibility has been gradually extended from ＂tackle-to-tackle＂ to ＂door-to-door＂. Thus, the port operator's period of responsibility was extended. The right of carriers to be limited in liability, although sometimes challenged, has not yet been modified; therefore, the port operator tends to be limited in liability.
Chapter Ⅳ presents solutions to the problems identified in the preceding studies. This chapter not only proposes a method for determining the legal status of the port operator, namely as ＂Contractual Assistants＂. More importantly, it examines the rationality of a port operator's liability limitation system under Chinese law and the legislative model for a port operator's liability limitation system. Based on the introduction of the international legislative model of the port operator's liability limitation system, the author recognises the rationality of the provisions stipulated in the current Chinese Maritime Law Draft for Examination. Finally, the author re-examines the provisions in the Maritime Law Draft for Examination and proposes specific legislative proposals to address the shortcomings exhibited therein.
Chapter Ⅴ presents the conclusion, which summarises the main concepts of the previous chapters and proposes future research directions.
The revision of China Maritime Law is currently at its final stages; therefore, an in-depth study of the legal system pertaining to port operators can provide a reference for the enhancement of the liability limitation system of port operators in China, which can facilitate the determination of the rights and obligations of the vessel, cargo, and port parties in maritime transportation and promote the healthy development of the port operation and maritime industries.Chapter Ⅰ Introduction 1
1.1 Background and Purpose of the Study 1
1.1.1 Construction of the Legal System for Chinese Ports under the ＂One Belt, One Road＂ Strategy 1
1.1.2 Revision of the China Maritime Law and Enhancement of the Port Operator Legal System 4
1.1.3 Current Scenario and Practical Problems of Port Operation Disputes in China 6
1.2 Methodology and Scope of the Study 8
1.2.1 Main Methodology of the Study 8
1.2.2 Main Contents of the Study 9
Chapter Ⅱ The Liability System of Port Operators and Issues under Chinese Law 12
2.1 Overview of the Port Operators 12
2.1.1 Emergence and Concept of the Port Operators 12
2.1.2 The Port Operators in China 13
2.1.3 Legislations on the Port Operators in China 16
2.2 Liability and Liability Limitation of Port Operators under Chinese Law 21
2.2.1 Liability of the Port Operators under the Contract 21
2.2.2 Provisions on the Liability of the Port Operators under Chinese Law 31
2.2.3 Provisons on the Liability Limitation of the Port Operators under Chinese Law 35
2.3 Cases and Issues on the Liability of Port Operators in Chinese Courts 39
2.3.1 The Port Operators as the Servants of the Carrier 40
2.3.2 The Port Operators as the Agents of the Carrier 44
2.3.3 The Port Operators as the Actual Carriers 46
2.3.4 The Port Operators as the Independent Contractors 49
2.4 Analysis of Problem Issues in the Liability System of Port Operators under Chinese Law 54
2.4.1 Evolution of the Port Operators' Legal Status under Chinese Law 54
2.4.2 Commentary on the Evolution of Legislations on Chinese Port Operators 55
2.4.3 Problem Issues of the Port Operators' Liability System under Chinese Law 56
Chapter Ⅲ Comparative Law Study on the Port Operators and their Limitation of Liability Systems 62
3.1 Comparative Law Examination on the Port Operator Concept 62
3.1.1 Legal Regulations of Major Countries 62
3.1.2 International Conventions and Others 67
3.2 Comparative Law Study on the Liability Limitation of Port Operator 72
3.2.1 Legal Regulations of Major Countries 72
3.2.2 International Conventions and Other 82
3.3 Summary 93
3.3.1 Analysis on the Port Operators' Concept under Comparative Law Examination 93
3.3.2 Analysis on the Port Operators' Limitation of Liability under Comparative Law Examination 94
Chapter Ⅳ Solutions for Improving the Port Operator's Liability Limitation System under Chinese Law 96
4.1 Analysis of the Rationality of the Port Operator's Liability Limitation System 96
4.1.1 Analysis of the Value of the Principle of Liability Limitation 96
4.1.2 Reasons for Introducing the Port Operator's Liability Limitation System into Chinese Law 99
4.2 Legislative Models of Port Operator's Liability Limitation System 105
4.2.1 International Legislative Models on Port Operator's Liability Limitation Systems 105
4.2.2 The Choice of Legislative Model of Port Operator's Liability Limitation System in China 108
4.3 Legislative Proposals on the Limitation of Liability of the Port Operators under China Maritime Law 114
4.3.1 Determining the Legal Status of the Port Operators 115
4.3.2 Specifying the Scope of Business of the Port Operators 116
4.3.3 Improving the Specifics of the Limitation of Liability for Port Operators 117
4.3.4 Unnecessary to Specify the Period of Responsibility of the Port Operators 119
4.3.5 Providing the Liability Limitation to the Port Operators' Servants and Agents 120
4.3.6 Introducing the Loss of Liability Limitation to the Port Operators and its Servants and Agents 122
Chapter Ⅴ Conclusion 123Docto
Experimental Study on the Effect of UREA Injection Amount Adjustment on SCR Performance
No full text산업화에 따른 전례 없는 기후변화와 환경오염에 국제사회의 대기오염 배출물질 규제는 지속적으로 강화되고 있는 추세이며, 이는 선박에서의 대기오염 배출물질 또한 예외가 될 수 없었다. 이에 UN 산하 국제해사기구는 MARPOL 부속서 제 Ⅵ장 선박에서의 대기오염 방지를 위한 규칙을 제정하여 대기오염을 규제하고 있으며 동 부속서가 발효되고 있다. 선박에서 발생하는 모든 대기오염물질의 배출을 통제하고 있으며 이러한 추세는 앞으로도 계속 이어질 것으로 전망된다.
규제 대기오염물질 중 하나인 질소산화물(NOx, Nitrogen Oxides)은 선박 추진기관 및 발전기관으로 많이 사용되는 디젤엔진에서 발생한다. NOx 배출가스 역시 MARPOL의 부속서 제 Ⅵ장에 따라 단계적으로 배출량을 저감하여야 하며 과거 TierⅠ배출기준 대비 TierⅢ 배출기준의 경우, 배출량의 80% 저감된 기준을 제시하고 있다. 강도 높은 환경규제에 맞추어 여러 가지 방법의 오염물질 저감 기술이 개발, 적용되었고 NOx 배출량을 약 80% 이상 저감할 수 있는 후처리 장치의 필요성이 대두되게 되었다.
이에 본 연구에서는 선박에 많이 적용되어 사용되고 있는 대표적인 후처리 장치인 SCR에 대해 실험을 진행하였다. 실선의 LP-SCR system 디젤엔진이 여러 가지 조건에서 운전될 때 배기가스를 분석하여 NOx 배출 특성 및 저감
효율을 살펴보고, 기관실 저장 탱크에서 1년 이상 된 요소수(Urea)를 사용했을 때 저감 성능을 확인해 보았다.
배기가스 분석기로 NOx 배출량을 비교하여 본 결과 TierⅡ 및 TierⅢ에서 배출량 기준을 만족하였다. TierⅢ의 경우 모든 실험엔진의 NOx 배출량이 15ppm 이하로 측정되었다. SCR 운전 중 Urea dosing rate를 정량적으로 증가시켜 NOx 배출량 변화를 확인한 결과, 대상 엔진의 모든 실험조건에서 NOx 배출량 변화는 극히 미미하였다. 증가 투입된 요소수는 NOx를 저감하는 용도로 사용되지 않고 암모니아 슬립의 형태로 대기 방출되었다고 유추할 수 있다. SCR 운전 중 Urea dosing rate를 정량적으로 감소시켜 NOx 배출량 변화를 확인한 결과, 모든 실험엔진의 요소수 투입량을 감소시킬수록 NOx 배출량은 증가했으며, 정량 100% (Auto) 투입하였을 때 최고의 저감 성능을 나타내도록 최적화되어 있음을 확인할 수 있었다. SCR 운전 전/후의 NOx(ppm) 저감율은 80%를 훨씬 상회하는 수준의 성능을 보여주었다. 본 실험 결과에 따르면 선박에서 1년 이상 된 요소수(보관온도 25℃~30℃)를 사용하였을 때 그 성능에는 큰 손실이 없는 것을 확인하였다.
향후 SCR 요소수 분사량 제어를 통한 암모니아 슬립 최소화, 전 구간 온도에서도 사용 가능한 요소수 또는 대체재 개발 등 다양한 측면에서 연구가 필요할 것으로 생각되며 본 연구가 아주 작은 도움이 될 수 있기를 바라본다.|Due to unprecedented climate change and environmental pollution caused by industrialization, the air pollutant emission regulations of the international community are continuously being strengthened. And air pollutant emissions from ships could not be an exception. The International Maritime Organization under the UN has established MARPOL Annex VI to prevent air pollution from ships to regulate air pollution, and the Annex is in effect. Emissions of all air pollutants generated from ships are being controlled, and this trend is expected to continue in the future.
Nitrogen Oxides (NOx), one of the regulated air pollutants, is generated from diesel engines, which are widely used for ship propulsion and power generation. Nitrogen Oxide emissions must also be reduced step by step according to MARPOL Annex VI, and in the case of Tier III emission standards compared to the previous Tier I emission standards, an 80% reduction in emissions is presented. In accordance with strict environmental regulations, various pollutant reduction technologies have been developed and applied, and the need for a post-treatment device that can reduce Nitrogen Oxide emissions by about 90% or more has emerged.
In this study, an experiment was conducted on SCR(Selective Catalytic Reduction), which is a representative post-processing device that is widely applied and used in ships. When the ship's LP-SCR system diesel engine is operated under various conditions, the exhaust gas was analyzed to examine the Nitrogen Oxide emission characteristics and reduction efficiency. The reduction performance of the SCR was checked when using urea solution water stored for more than one year in the storage tank in E/R.
As a result of comparing Nitrogen Oxide emissions with an exhaust gas analyzer, the emission standards were satisfied in Tier II and Tier III. In case of Tier III, Nitrogen Oxide emissions from all experimental engines were measured to be less than 15 ppm. As a result of confirming the NOx emission change by quantitatively increasing the urea dosing rate during SCR operation, the NOx emission change of all the experimental engines was extremely insignificant. It can be inferred that the increased input urea was not used for reducing NOx but was released into the atmosphere in the form of ammonia slip. As a result of confirming the NOx emission change by quantitatively reducing the urea dosing rate during SCR operation, the NOx emission increased as the urea input of all experimental engines was reduced. It was confirmed that it was optimized to show the best reduction performance when 100% (Auto) of urea dosing rate was injected. The NOx (ppm) reduction rate before and after SCR operation showed a level of performance well above 80%. According to the results of this experiment, it was confirmed that there was no significant loss in performance when using urea (storage temperature 25 ℃ ~ 30 ℃) with a period of more than one year in a ship.
In the future, it is considered that research is needed in various aspects, such as minimizing ammonia slip through control of SCR urea injection amount and developing urea or alternatives that can be used at all temperature ranges. I hope that this study will be of even a little help.1. 서 론 1
1.1 연구 배경 1
1.2 선행연구 및 연구 목적 3
2. 관련 규정 및 저감 기술 고찰 5
2.1 선박에서의 대기 오염 관련 규정(NOx Technical code) 5
2.2 NOx Technical File 8
2.3 질소 산화물 저감 기술 11
2.3.1 EGR system 12
2.3.2 SCR system 13
3. 실험 장치 및 방법 15
3.1 실험 장치 15
3.1.1 실험 SCR 15
3.1.2 실험 엔진 23
3.1.3 측정장비 25
3.1.4 사용된 연료유 및 Urea 27
3.2 실험 방법 31
3.2.1 배기가스 측정 31
3.2.2 배기가스 측정 포인트 34
3.2.3 Urea dosing rate 조정 35
4. 실험 결과 및 고찰 38
4.1 4행정 디젤엔진 연소가스 Emission 38
4.1.1 SCR 운전 전/후 Emission 비교 38
4.1.2 SCR Urea dosing rate 증가에 따른 Emission 비교 40
4.1.3 SCR Urea dosing rate 감소에 따른 Emission 비교 43
4.1.4 Aging Urea 사용에 따른 NOx Emission 비교 47
5. 결론 48
참고문헌 50Maste
A Study on the Traffic Safety Measures for the Large Ships in the Congested Area of Busan New Port using Analytic Hierarchy Process
No full text부산항은 세계 제2위의 컨테이너 화물 환적 항만으로 2022년 전국항만에서 처리한 환적 컨테이너 화물 1,215만 TEU 중 약 3/4을 처리하였으며, 부산신항은 부산항의 전체 물동량 2,207만 TEU 중 약 2/3에 해당하는 1,524만 TEU를 처리하고 있다. 또한 부산신항은 2013년 이후 10년간 물동량이 139.0%로 증가하여 지속적인 증가 추세를 나타내고 있다. 이러한 물동량 증가 추세에 따라 2020년부터는 세계 최대규모의 컨테이너 선박인 G/T 228,000톤급(24,000TEU급)의 극초대형 컨테이너 선박이 입항하기 시작하여 선박들의 초대형화 추세를 이어가고 있다. 2022년 6월에는 부산신항 개발 2-4단계의 남 컨테이너 터미널 6부두에 극초대형 컨테이너 선박의 접안이 가능한 3개의 선석이 추가로 개장되어 운영되고 있다. 그리고 2023년 10월에는 극초대형 컨테이너 선박의 접안이 가능한 서 컨테이너 터미널 3개 선석의 추가 개장이 예정되어 있다. 부산신항은 개장 후에 토도를 제거하여 통항로의 폭을 확장하였으나 현재 가장 협소한 서 방파제 부근의 항로 폭은 710m로서 변함이 없어 초대형 컨테이너 선박들과 극초대형 컨테이너 선박들이 교행하기에는 항로 폭이 충분하지 못하다. 서 컨테이너 터미널이 완전 개장될 경우 초대형 입출항 선박들로 인하여 서 방파제와 호란도 부근의 해역은 혼잡구역으로서 다양한 조우 상황의 발생이 불가피하여 충돌의 위험 등 해양사고의 발생 우려가 잠재하고 있다.
따라서 본 연구는 부산신항 입출항 통항로 내 대형선박의 통항 안전대책 향상을 위하여 자연 환경, 선박들의 입출항 현황과 해상교통 흐름, 그리고 부산신항에서 발생한 해양 사고와 준 해양사고 발생 사례와 우리나라의 항로 안전대책 등을 분석하였다. AHP 기반 설문조사를 활용하여 대상 해역의 이용자들로부터 통항로의 위험 요소 및 안전대책을 식별한 결과, 통항로의 가장 큰 위험요소는 교통 혼잡도이며, 위험 요소를 해소하기 위한 안전대책으로는 일방 통항 구역 설정 등의 교통 제도의 도입이 바람직하다고 판단하였다.
또한 AHP 기반 설문조사에서 도출된 안전대책을 기반으로 ES model을 이용하여 시나리오를 설정한 후에 해상교통류 시뮬레이션을 실시하여 각 안전대책에 대한 교통 위험도를 정량적으로 파악하였다. 설문조사와 해상 교통 위험도 평가 결과, 대형선박의 입출항 시 혼잡구역 내 일방 통항 구역 설정, 통항분리대 설정, 항로표지 이설에 의한 항로 폭 확장, 가상 항로표지 활용 순으로 위험 비율 감소 효과 크게 나타났음을 확인하였다. 서 컨테이너 터미널 개장 시의 위험 비율 13.19%에 대비 2.74% 감소한 일방 통항 구역의 설정이 가장 큰 위험 비율(10.45%) 감소 효과를 보여 가장 중요한 안전대책으로 판단하였다. 이는 통항로의 위험도 경감에 큰 효과가 있는 것으로 분석되었기 때문에 300m 이상의 대형선박들에 한해서 시차를 둔 일방 통항의 실시 등 부산신항의 통항 환경 변화에 따른 조속한 제도의 마련이 필요한 것으로 사료된다. 그리고 해당 도선구의 도선사들을 인터뷰한 결과 일방 통항 구역 설정 다음으로 제5항로상에 설치된 110번 부표를 기존보다 150m 동쪽으로 이설하고 항로를 준설하여 항로 폭을 확장시키는 방안도 위험을 감소시킬 수 있음을 시사하였다.
본 연구는 부산신항 통항로 내 대형선박의 통항 안전 향상을 위하여 안전대책에 대한 우선순위를 파악하고 항로의 위험도를 정량적으로 평가하였으므로 제도 마련의 기초가 될 수 있을 것으로 생각된다.
향후의 추가 연구에서는 서 컨테이너 터미널 추가 개장 후 실제 선박들의 교통량과 교통흐름을 분석하여 본 연구에서 제시한 안전대책에 대한 효과의 검증이 필요하다. 또한, 일방 통항 구역 설정 시 일방 통항에 따른 선박의 대기에 관한 사항 그리고 구체적인 일방 통항 방법 등에 대하여 연구가 추가적으로 필요할 것이다.List of Tables iv
List of Figures v
Abstract vi
1. 서 론 1
1.1 연구의 배경 및 목적 1
1.2 논문의 구성 3
2. 대상해역의 환경요소 조사‧분석 5
2.1 대상해역의 범위 5
2.2 자연환경 분석 6
2.2.1 바람 6
2.2.2 조류 8
2.3 교통 현황 분석 9
2.3.1 부산신항 항만 현황 9
2.3.2 부산신항 입출항 현황 13
2.3.3 선행연구 고찰 15
2.3.4 부산신항 교통흐름 분석 18
2.4 해양사고 및 준해양사고 사례 21
2.4.1 해양사고와 준해양사고의 정의 21
2.4.2 해양사고의 발생 요인 23
2.4.3 부산신항 해양사고와 준해양사고 사례 24
2.4.4 부산신항 해양사고와 준해양사고의 시사점 28
2.5 우리나라의 항로 안전대책 사례 28
2.5.1 통항분리방식의 적용 29
2.5.2 해상교통안전진단에 따른 항로 안전대책 29
2.5.3 VTS 설치를 통한 항로 안전대책 30
3. AHP 분석을 통한 위험 요소 및 안전대책 도출 33
3.1 AHP 기법 개요 33
3.2 부산신항 통항로 내 위험 요소 및 안전대책 요소 식별 34
3.3 분석 결과 37
3.3.1 설문 응답자 세부 사항 38
3.3.2 부산신항 통항로 위험요소의 중요도 산출 40
3.3.3 부산신항 통항로 안전대책의 중요도 산출 42
4. ES 모델을 이용한 안전대책의 위험도 평가 44
4.1 ES 모델의 개요 44
4.2 안전대책 기반 시나리오 설정 및 평가 방법 47
4.3 서 컨테이너 터미널 개장에 따른 위험도 평가 49
4.4 안전대책에 의한 시나리오별 위험도 평가 50
4.4.1 항로표지 이설을 통한 항로 폭 확장 50
4.4.2 가상 항로표지에 의한 교통흐름 분리 51
4.4.3 통항 분리대 설정을 통한 교통흐름 분리 52
4.4.4 일방 통항 구역 설정을 통한 통항 제한 53
4.5 해상교통류 시뮬레이션 결과 55
5. 부산신항 혼잡구역 내 대형선 통항 안전 향상 방안 56
5.1 AHP 설문 및 시뮬레이션 결과에 따른 안전대책 56
5.1.1 일방 통항 구역 설정을 통한 통항 제한 56
5.1.2 항로표지 이설을 통한 항로 폭 확장 56
5.2 안전대책의 종합적 비교 결과 57
6. 결론 59
참고문헌 62
국문초록 68
부록 71Maste
Evaluation Models for Safe Ship Operation through Data Driven Approach using AIS Information
No full textHerein, a study was conducted to derive quantitative methods for improving safety using Automatic Identification System (AIS) data. The study involved constructing algorithms using data mining techniques, including clustering analysis and regression analysis, based on a data-driven approach. The aim was to enable ships to operate safely.
According to the 5th long-term development plan for the shipping industry, sea transport accounted for 99.8% of Korea's import and export cargo volume. The percentage of small container ships, with a capacity of 8,000 Twenty-foot Equivalent Units (TEU) or less, has been steadily declining, while the proportion of large container ships, exceeding 8,000 TEU, is rapidly increasing. It is expected that in the near future, there will be a rise in mega-sized container ships exceeding 400m in Length overall (LOA), driven by the rapid advancements in this field.
The trend towards mega-sizing of ships has a significant impact on the design of port facilities, including the length of berths, the width of fairways, turning points, and construction of bridges across waterways. Additionally, offshore wind farms, a rapidly growing source of renewable energy, have emerged in recent years. It is crucial to ensure that these offshore facilities do not interfere with ship traffic. This study focused on four key factors related to ship operation safety: predicting future ship specifications, analyzing safety navigation width, assessing annual collision probability, and determining the optimal maritime traffic route for offshore wind farms, taking collision frequency into consideration.
First, the future main specifications of a 30,000 TEU container ship were predicted using regression and cluster analysis among various data mining algorithms. A dataset of 5,497 container ships, registered with the International Maritime Organization (IMO) and up to 20 years old, was utilized for this analysis. The ships were categorized based on variations in their dimensions using the k-means clustering algorithm. This clustering allowed for the examination of Deadweight tonnage (DWT), TEU capacity, LOA, Length between perpendiculars (Lpp), Breadth (B), and maximum draft (d) of container ships, with a coverage rate of 75%. The results revealed that a container ship with a capacity of 30,000 TEUs is estimated to have an LOA of 428.4m, a B of 67.6m, and a d of 17.0m.
Secondly, among the data mining algorithms employed, cluster analysis, dimensionality reduction classification through Principal Component Analysis (PCA), and statistical analysis were utilized to determine the safety navigational width for ships passing under bridges across waterways. This study focused on analyzing traffic distribution characteristics and deriving optimal traffic distribution for four cable-stayed bridges in Korea: Incheon Bridge, Busan Harbor Bridge, Mokpo Bridge, and Machang Bridge. The goodness-of-fit test was employed to achieve this. By assuming a safe passage range of 95% confidence interval and considering both lognormal and normal distributions, the analysis results were obtained.
In the case of Incheon Bridge, the largest difference between the normal distribution and the lognormal distribution was observed in the range of 64m to 98m. On the other hand, a minimum difference of 10m was found at Machang Bridge. Consequently, it was determined that presenting the safety navigational width of traffic using the lognormal distribution was more suitable for Incheon Bridge, whereas for the other bridges, similar results could be obtained using either the normal or lognormal distribution due to the similarities in width between the two distributions.
Thirdly, an analysis of annual collision probability was conducted from a probabilistic standpoint. In the Ministry of Oceans and Fisheries (MOF), the Maritime Traffic Safety Assessment (MTSA) evaluates the impact of maritime development, including bridges across waterways, on maritime traffic safety. However, the current system employs collision probability per 10,000 vessels as a safety standard based on the number of collisions per vessel, rather than considering the annual collision frequency during collision risk assessments using ship handling simulations. This approach is inadequate for verifying safety in areas with high maritime traffic.
To address this issue, this study employed the annual frequency of collapse (AASHTO Method II) to convert collision frequency per ship into an equation representing the annual collision frequency for four bridges across waterways in Korea. A normality test was performed, and passing ships were clustered by tonnage using k-means clustering. The annual collision frequency was then calculated for each cluster. The analysis revealed that an annual collision frequency of once every 50 to 100 years was suitable, depending on the size of the ship. This finding aligns with the annual collision frequency reported by the IMO.
Furthermore, the study examined the change in collision probability when a mega-sized ship, with the predicted main dimensions (428.4m x 67.6m) of the 30,000 TEU container ship, is introduced in the future. The analysis demonstrated that the annual collision probability decreased from 103.4 years to 70.9 years. Consequently, it is crucial to ensure the provision of a sufficiently wide main span when designing bridges across waterways, taking into account the potential presence of large ships in the future.
Lastly, an analysis was conducted on the optimal route planning method for offshore wind farms from the perspective of collision frequency. The study examined the traffic density in the target area based on 20 months of Big AIS data, both before and after the installation of Floating-LiDAR (Light Detection and Ranging) devices, which are used for measuring wind resources in the sea area near Ulsan Exclusive Economic Zone (EEZ). The analysis revealed that after the installation of Floating-LiDAR, the traffic flow in the area was divided into three distinct flows.
Subsequently, traffic distribution was modeled assuming the presence of a floating wind farm, based on the results of the traffic density analysis. Using this modeled traffic distribution, ship-to-ship collisions were analyzed using IWRAP Mk II, and ship-to-offshore wind farm collisions were comprehensively examined using the COWI A/S model. The optimal maritime traffic route was determined by applying the ALARP (As Low As Reasonably Practicable) principle.
The results indicated that when establishing a corridor, the ALARP criteria set in this study were met when the corridor width was set at 4,000m, the buffer zone was set at 1,500m, and the outer separation distance was approximately 1,852m (1.0 Nautical Mile). When only detour traffic was allowed without a corridor, the ALARP criteria were satisfied with an outer separation distance of 2,037m (1.1 Nautical Miles) or more. According to the ALARP setting criteria, the proposed optimal maritime traffic method presented an appropriate safety range corresponding to a collision frequency of once every 126 to 128 years.
Therefore, it was determined that securing a navigation route of approximately 4 km and a buffer zone of over 1.5 km would satisfy the ALARP criteria set in this study, potentially reducing the detour area. In other words, establishing a corridor was deemed the optimal route from the maritime traffic perspective. However, it should be noted that regardless of the existing navigation method, the installation of an offshore wind farm increases the collision risk by approximately three times compared to the existing traffic flow. To mitigate the frequency of accidents, additional safety operational measures will be necessary.
The practical implications of this study can greatly contribute to the safety of ship operations. The methods developed in this study enable quantitative decision-making based on data, rather than relying solely on empirical factors, when it comes to ensuring the safety of ship operations. By adopting these data-driven approaches, we can enhance the safety operations of both port facilities and ships, providing a stronger foundation for overall maritime safety.1. Introduction 1
1.1. Background and purpose of this study 1
1.2. Scope and composition of this study 7
2. Materials and methods 13
2.1. Target data 13
2.2. Data preprocessing 20
2.3. K-means clustering 26
2.4. Standards of ship’s main dimensions 29
1) Korean harbor and fishery design criteria 29
2) Previous studies in Japan 29
3) Previous studies in overseas 30
2.5. Traffic distribution characteristic 31
1) Normality test 31
2) Goodness-of-fit test 32
3) Safety distance between ship and bridge pier 34
2.6. Annual collision frequency estimation 35
1) Macduff’s model 35
2) Fujii’s model 36
3) Pederson’s model 36
4) COWI A/S model 37
5) Previous study in Korea 38
6) IWRAP (IALA Waterway Risk Assessment Program) Mk II 39
7) Relationship with Causation factor 40
3. Prediction of trends in mega-sized ship’s main dimensions 42
3.1. Analysis method and coverage rate concept 42
3.2. Results of k-means clustering in ship’s main dimensions 47
3.3. Design criteria of container ships 55
1) Results of regression analysis 55
2) Comparison of results with previous study 67
3) Prediction of trends for mega-sized container ship 69
3.4. Discussion 73
4. Ship safety navigational width at bridge across waterway 74
4.1. Result of k-means clustering in traffic distributions 74
4.2. Analysis of traffic distribution characteristic by clustered data 108
1) Results of Normality test 108
2) Results of Goodness-of-fit test 110
3) Safety navigational width by clustered data 133
4.3. Discussion 137
5. Annual collision frequency at bridge across waterway 138
5.1. Annual collision risk assessment model 138
5.2. Results of annual collision probability 142
1) Results of actual annual collision probability 142
2) Standard of collision risk assessment according to AASHTO method II 146
5.3. Discussion 151
6. Optimal maritime traffic route for offshore wind farms considering collision frequency 155
6.1. Analysis method and traffic distribution modeling 155
6.2. Results of optimal maritime traffic route considering collision frequency 159
1) Separation distance between offshore wind farm and maritime traffic routes 159
2) Establishing a corridor 160
3) Detour navigation 162
6.3. Discussion 163
7. Conclusion 166
7.1. Conclusion of this study 166
7.2. Future works 170
References 173Docto
Study of Piezoelectric Energy Harvesting Using Solar Radiation Pressure Enhanced by ITO/Ag Double Layer Structure
No full textThe output characteristics of the device of light pressure electric generator (LPEG), which harvests piezoelectric energy using solar radiation enhanced by surface plasmon (SPs), have been improved to increase the possibility of application in real life. Conventional LPEG device was optimized so that surface plasmons can strongly resonate in visible light, but the device's output is still insufficient for practical applications. The near-infrared (NIR) region accounts for more than 50% of the total energy of sunlight reaching the earth’s surface, the power of an LPEG device could be improved by using both visible and NIR light together. The LPEG device was fabricated by forming a crater structure capable of concentrating light on a GaAs (100) substrate and by sequentially depositing layers to form an indium tin oxide (ITO)/Ag/Pb (Zr,Ti)O3(PZT)/Pt/Ti structure. By using an ITO/Ag bilayer that excites surface plasmons in the near-infrared and visible regions, respectively, the solar radiation pressure from the visible to the near-infrared regions was used as an energy source. The LPEG with the ITO layer generates an open-circuit voltage of 295 mV, a short-circuit current of 3.78 μA, and power of 532.3 μW/cm2 under a solar simulator, and The power of the LPEG device incorporating the ITO layer increased by 38% compared to the device without the ITO layer. In addition, by separating the wavelength of sunlight using an optical bandpass filter, the effect of the ITO layer on the electrical output of the LPEG device was analyzed when visible and NIR light was incident. The electric field distribution according to the light wavelength was analyzed through finite-difference time-domain (FDTD) simulation, and it was confirmed that the pressure of the incident light was further amplified by the ITO/Ag bilayer. Finally, the electrical energy harvested from the LPEG device was stored in a capacitor to drive red light-emitting diodes to show real-life applicability.|표면 플라즈몬에 의해 증폭된 태양복사압을 이용하여 압전에너지를 수확하는 light pressure electric generator(LPEG)의 소자의 실생활 응용 가능성을 높이기 위해 출력 특성을 향상시켰다. 기존의 LPEG 소자는 가시광대역의 빛에서의 표면 플라즈몬이 강하게 공명할 수 있도록 최적화하였지만 소자의 출력은 여전히 실생활에 응용하기에는 부족하다. 태양광의 전체 에너지 중 근적외선대역이 50 % 이상을 차지하므로 LPEG 소자의 전력은 가시광선과 근적외선의 빛을 함께 사용함으로써 크게 향상되었다. LPEG 소자는 GaAs (100) 기판에 빛을 집광할 수 있는 crater 구조를 제작하고 ITO/Ag/PZT/Pt/Ti/GaAs 층을 순차적으로 형성하여 제작되었다. 근적외선대역과 가시광대역에서 각각 표면 플라즈몬을 여기시키는 ITO/Ag 이중충을 이용함으로써 가시광에서 근적외선대역까지의 태양복사압을 에너지원으로 이용하였다. ITO 층이 있는 LPEG 소자는 solar simulator하에서 295 mV의 open-circuit voltage, 3.78 μA의 short-circuit current 및 532.3 μW/cm2의 전력을 생성하였는데, ITO 층이 없는 경우에 비하여 전력이 약 38% 증가하였다. 또한, optical bandpass filter를 이용해 태양광의 파장을 분리함으로써 가시광대역과 근적외선대역의 빛이 입사될 때 ITO 층이 LPEG 소자의 전기적 출력에 미치는 영향을 분석하였다. 입사되는 빛의 파장에 따른 전기장 분포는 finite-difference time-domain (FDTD) 시뮬레이션을 통해 분석하였으며, 입사광의 압력은 ITO/Ag 이중층으로 인해 더욱 증폭될 수 있음을 확인하였다. 마지막으로, LPEG 소자에서 수확된 전기 에너지를 커패시터에 저장하여 red light-emitting diodes를 구동하여 실생활 응용가능성을 보였다.1. 서론 1
1.1 에너지 하베스팅의 필요성 1
1.2 다양한 에너지 하베스팅 기술 3
1.2.1 압전 에너지 하베스팅 기술 3
1.2.2 마찰전기 에너지 하베스팅 기술 5
1.2.3 자기-기계-전기 에너지 하베스팅 기술 7
1.2.4 열전 하베스팅 기술 8
1.2.5 태양전지 10
1.3 태양복사압을 이용한 에너지 하베스팅 소자 13
1.4 본 연구의 목적 14
2. 이론 17
2.1 태양광 17
2.1.1 빛의 성질 17
2.1.2 포인팅 벡터와 복사압 18
2.1.3 태양광의 특성 19
2.2 표면 플라즈몬 21
2.2.1 표면 플라즈몬의 종류 22
2.2.2 표면 플라즈몬이 발생하는 물질의 종류 26
2.2.3 표면 플라즈몬 발생파장과 굴절률의 관계 34
2.3 압전 효과 35
3. 실험 방법 36
3.1 ITO/Ag 이중층이 결합된 LPEG 소자의 제작 방법 36
3.2 LPEG 소자의 작동 매커니즘 39
3.3 FDTD simulation을 통한 입사 파장에 따른 ITO/Ag 이중층에서의 전기장 분석 41
3.4 COMSOL multiphysics simulation을 통한 입사 파장에 따른 압전 전위 분포 경향 분석 43
4. 결과 및 고찰 45
4.1 ITO/Ag 이중층이 결합된 LPEG 소자의 구조 및 광학적 특성 45
4.1.1 3D optical microscopy를 이용한 crater 구조의 형상 분석 45
4.1.2 ITO/Ag 이중층이 결합된 LPEG 소자의 구조적 분석 48
4.1.3 PZT 층의 결정성 분석 51
4.1.4 Ag 층에서의 Ag 나노입자 크기 분포 및 광학적 특성 분석 53
4.1.5 FDTD simulation을 이용한 ITO 층의 광학적 특성 분석 55
4.2 ITO/Ag 이중층이 결합된 LPEG 소자의 전기적 특성 57
4.2.1 입사되는 빛의 파장에 따라 ITO 층이 전기적 출력에 미치는 영향과 출력 향상의 원인 분석 57
4.2.2 태양광에 의한 LPEG의 전기적 출력 65
4.3 ITO/Ag 이중층이 결합된 LPEG 소자의 응용 68
5. 결론 71
참고문헌 72Maste
Prediction of Shale Gas Production based on Long Short-Term Memory Neural Networks considering Production Characteristics
No full text현장에서는 셰일가스의 생산량 예측을 위하여 일반적으로 생산감퇴곡선분석법을 활용하고 있지만, 이는 생산정 정보, 수압파쇄 인자 등의 생산관련인자나 생산량을 좌우하는 생산운영조건을 고려할 수 없다는 한계가 존재한다. 또한, 생산감퇴곡선분석법 적용 시 생산이력이 충분하지 않을 경우에는 결과에 대한 불확실성이 존재한다. 이러한 어려움을 극복하기 위해 최근에는 딥러닝의 일종인 순환신경망 기반의 장단기기억을 이용하여 시간에 따라 변화하는 생산량 및 생산거동을 예측하는 연구가 이루어지고 있다. 기존의 연구에서는 장단기기억 모델에 생산이력만을 이용하여 생산량을 예측하거나, 생산운영조건을 함께 활용하여 예측결과를 개선한 바 있다. 그러나 셰일층의 생산성에 복합적인 영향을 미치는 생산관련인자를 반영하거나 주어진 생산이력으로부터 생산감퇴특성을 추출하여 활용하는 방법에 관해서는 연구가 부족한 상황이다.
이 연구에서는 셰일가스의 생산량을 예측하기 위하여 장단기기억 기반의 예측모델을 구축하고, 생산이력과 더불어 각 생산정의 특성을 반영할 수 있도록 생산관련인자, 생산감퇴특성과 같은 생산특성인자를 추가 입력자료로 이용하여 생산량을 예측하고자 하였다. 생산 초기의 생산이력을 바탕으로 48개월까지의 생산량을 장기적으로 예측할 수 있는 장단기기억 신경망을 구축하였으며, 생산량 예측모델로써 장단기기억 모델의 활용 가능성을 파악하였다. 또한, 각 생산정의 생산관련인자 또는 생산감퇴특성을 고려할 수 있는 장단기기억 기반 예측모델을 구축하였으며, 생산특성인자를 고려한 모델과 생산이력만을 이용한 모델 간 생산량 예측결과의 비교를 통해 생산이력과 더불어 생산특성인자를 추가 입력자료로 활용함으로써 예측성능을 개선할 수 있음을 확인하였다. 이러한 연구 결과를 통하여 생산감퇴곡선분석법의 적용이 어려운 생산 초기에도 생산특성인자를 고려한 장단기기억 신경망을 바탕으로 신뢰성 있는 셰일가스 생산량 예측이 가능할 것으로 사료된다.|Decline curve analysis (DCA) has been widely employed to predict shale gas production. Unfortunately, DCA has limitations that negate production-related factors such as well information, hydraulic fracturing conditions, or operating conditions that influence production. If production history is insufficient when applying a DCA, there is a degree of uncertainty in the results. To address these difficulties, recent research has been conducted to predict production and production behavior over time using Long Short-Term Memory (LSTM) based on recurrent neural networks, a type of deep learning. In previous studies, production has been predicted using only the production history in LSTM models, or prediction results have been improved by incorporating operating conditions along with production history.
In this study, a prediction model based on LSTM was established to predict shale gas production, and production characteristics such as production-related factors and decline characteristics were added as input data to reflect the characteristics of each well. LSTM neural networks were built using the production history in the early stages of production, enabling predictions of production in the long term up to 48 months, and the potential use of LSTM as a prediction model was identified. Additionally, LSTM-based prediction models that take into account production-related factors or decline characteristics of each well were established. The comparison of results between the model considering production characteristics and the model using only production history confirmed that prediction performance can be improved by incorporating production characteristics as additional input data. Based on the results of this study, it is believed that reliable shale gas production can be predicted using LSTM neural networks, taking into account production characteristics, even in the early stages of production when DCA is difficult to apply.1. 서 론 1
2. 셰일 저류층에서의 생산량 예측 3
2.1 셰일 저류층의 특징 4
2.2 인공지능 기반 생산량 예측 6
2.3 연구 사례 분석 10
3. 생산이력 기반의 셰일가스 생산량 예측 16
3.1 연구대상 지역 16
3.2 현장자료 취득 및 자료 전처리 17
3.3 LSTM 예측모델 설계 20
3.3.1 예측 방법 및 입‧출력자료 구성 20
3.3.2 Hyperparameter 설정 및 최적화 21
3.4 생산이력을 활용한 생산량 예측 26
3.4.1 생산량 예측결과 27
3.4.2 초기 생산량에 따른 예측성능의 경향 파악 29
4. 생산특성인자를 고려한 셰일가스 생산량 예측 31
4.1 셰일층 특성 반영을 위한 추가 입력자료 31
4.2 생산관련인자를 이용한 생산량 예측 33
4.2.1 생산관련인자 선정 및 예측모델 설계 33
4.2.2 생산량 예측결과 37
4.3 생산감퇴특성을 활용한 생산량 예측 40
4.3.1 생산감퇴특성 선정 및 예측모델 설계 40
4.3.2 생산량 예측결과 42
4.4 LSTM 모델별 생산량 예측결과 분석 45
5. 결 론 48
참고문헌 50Maste