Journal of Marine Science and Engineering

Research

25 pages, 3460 KiB

Open AccessArticle

Life Cycle Cost Analysis for Scotland Short-Sea Ferries

by Insik Hwang, Chybyung Park and Byongug Jeong

J. Mar. Sci. Eng. 2023, 11(2), 424; https://doi.org/10.3390/jmse11020424 - 15 Feb 2023

Cited by 4 | Viewed by 3037

The pathway to zero carbon emissions passing through carbon emissions reduction is mandatory in the shipping industry. Regarding the various methodologies and technologies reviewed for this purpose, Life Cycle Cost Analysis (LCCA) has been used as an excellent tool to determine economic feasibility [...] Read more.

The pathway to zero carbon emissions passing through carbon emissions reduction is mandatory in the shipping industry. Regarding the various methodologies and technologies reviewed for this purpose, Life Cycle Cost Analysis (LCCA) has been used as an excellent tool to determine economic feasibility and sustainability and to present directions. However, insufficient commercial applications cause a conflict of opinion on which fuel is the key to decarbonisation. Many LCCA comparison studies about eco-friendly ship propulsion claim different results. In order to overcome this and discover the key factors that affect the overall comparative analysis and results in the maritime field, it is necessary to conduct the comparative analysis considering more diverse case ships, case routes, and various types that combine each system. This study aims to analyse which greener fuels are most economically beneficial for the shipping sector and prove the factors influencing different results in LCCA. This study was conducted on hydrogen, ammonia, and electric energy, which are carbon-free fuels among various alternative fuels that are currently in the limelight. As the power source, a PEMFC and battery were used as the main power source, and a solar PV system was installed as an auxiliary power source to compare economic feasibility. Several cost data for LCCA were selected from various feasible case studies. As the difficulty caused by the storage and transportation of hydrogen and ammonia should not be underestimated, in this study, the LCCA considers not only the CapEx and OpEx but also fuel transport costs. As a result, fuel cell propulsion systems with hydrogen as fuel proved financial effectiveness for short-distance ferries as they are more inexpensive than ammonia-fuelled PEMFCs and batteries. The fuel cost takes around half of the total life-cycle cost during the life span. Full article

(This article belongs to the Special Issue Marine Alternative Fuels and Environmental Protection II)

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17 pages, 5864 KiB

Open AccessArticle

A Study on the Enhanced Process of Elaborate Heat Source Model Parameters for Flux Core Arc Welding of 9% Nickel Steel for Cryogenic Storage Tank

by Changmin Pyo, Se-Min Jeong, Jaewoong Kim, Minho Park, Jihoon Shin, Younghyun Kim, Joonsik Son, Jeong-Hwan Kim and Myoung-Ho Kim

J. Mar. Sci. Eng. 2022, 10(12), 1810; https://doi.org/10.3390/jmse10121810 - 23 Nov 2022

Cited by 4 | Viewed by 1878

Abstract

Various regulations are being devised and implemented to prevent the environmental pollution that is threatening mankind. The International Maritime Organization has strengthened regulations on sulfur, a notorious pollutant, to prevent sea pollution. In addition, the production of LNG fueled ships is increasing. Among [...] Read more.

Various regulations are being devised and implemented to prevent the environmental pollution that is threatening mankind. The International Maritime Organization has strengthened regulations on sulfur, a notorious pollutant, to prevent sea pollution. In addition, the production of LNG fueled ships is increasing. Among various metals, 9% nickel steel is widely used in the shipbuilding industry because it is advantageous in terms of material strength and cryogenic impact toughness. Various studies are being carried out to predict and prevent its distortion, caused by welding, in the design. To predict welding distortion during flux core arc welding, this study found a way to refine the parameters constituting the Goldak welding heat source. The optimal heat source parameters were derived by using BOP experiments, cross-sectional analysis, finite element analysis and global optimization algorithm. When re-analyzed and verified based on the values, an error of up to 6.3% was found between simulation results and experimental values. The process was improved by clarifying the objective function and reducing the range of candidate welding efficiencies during global optimization and the process efficiency was also improved by reducing analysis time with a simplified model. Therefore, it is thought that this study can contribute to the productivity improvement of LNG storage containers, helping engineers apply it immediately in the industrial field. Full article

(This article belongs to the Special Issue Marine Alternative Fuels and Environmental Protection II)

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17 pages, 3032 KiB

Open AccessArticle

Hybrid Multi-Criteria Decision-Making for Marine SOx Scrubber Systems

by Jaehoon Jee

J. Mar. Sci. Eng. 2022, 10(11), 1599; https://doi.org/10.3390/jmse10111599 - 30 Oct 2022

Cited by 5 | Viewed by 2230

Abstract

This paper aims to identify the best solution for three SOx scrubber systems by evaluating their economic, environmental and technical performances: open-loop, closed-loop and hybrid scrubber systems. It adopted a novel muti-criteria decision-making model which can be introduced as the combination of lifecycle [...] Read more.

This paper aims to identify the best solution for three SOx scrubber systems by evaluating their economic, environmental and technical performances: open-loop, closed-loop and hybrid scrubber systems. It adopted a novel muti-criteria decision-making model which can be introduced as the combination of lifecycle cost and lifecycle assessments, and fuzzy-TOPSIS and fuzzy-AHP. The analysis results of the case study of 72,100 gross-ton cargo ships suggested that the closed-loop scrubber systems would be the most effective in the consideration of all of the aspects, overall. It also shows the excellence of the proposed decision-making model to remedy the shortcomings of the conventional multi-criteria decision-making process by directing the analytic process in a wiser way, by means of fuzzy elements. For the environmental impact assessment, the lifecycle assessment approach enables one to obtain a holistic view of the Lifecycle emissions from the cradle to the grave. This paper finally shows the effectiveness of the proposed method, which can improve confidence in decision-making by extending a short-term view widely. Therefore, it was strongly believed that the proposed model is not necessarily/limitedly applied to marine systems but can be broad and noteworthy for a variety of studies requiring appropriate decision-making. Full article

(This article belongs to the Special Issue Marine Alternative Fuels and Environmental Protection II)

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20 pages, 48968 KiB

Open AccessArticle

Development of a Marine LPG-Fueled High-Speed Engine for Electric Propulsion Systems

by Kang Woo Chun, Myongho Kim and Jae-Jung Hur

J. Mar. Sci. Eng. 2022, 10(10), 1498; https://doi.org/10.3390/jmse10101498 - 14 Oct 2022

Cited by 10 | Viewed by 2212

Abstract

As regulations on emissions from ships become stricter worldwide, new propulsion systems and the use of eco-friendly fuel are being introduced as alternative solutions. Therefore, many studies on electric propulsion systems using various power sources are being conducted. Conventional diesel propulsion systems are [...] Read more.

As regulations on emissions from ships become stricter worldwide, new propulsion systems and the use of eco-friendly fuel are being introduced as alternative solutions. Therefore, many studies on electric propulsion systems using various power sources are being conducted. Conventional diesel propulsion systems are available from small to large scale, but in the case of LPG propulsion systems, some specifications are limited, and their application is impossible. In addition, due to the limitations of the companies participating in the development of small and medium-sized engines, marine empirical research into existing shore engines is required rather than developing new engines. In this study, a generator using LPG fuel was developed for such an eco-friendly electric propulsion system and tested in the field. Accordingly, a 230 kW-class waterjet type LPG engine for electric propulsion was developed and developed for patrol ships, which are small and medium-sized ships. A system that considers the marine environment was developed, and various data were recorded through test operation under various loads. The results of this study can be used for the development of various auxiliary engine systems, and the test operation procedure of this development can be applied to the development of small and medium-sized LPG engines of different capacities. In addition, it can have a big impact on the business of converting marine engines from onshore engines. However, the development costs and improving the efficiency are still areas to be further improved through future research. Full article

(This article belongs to the Special Issue Marine Alternative Fuels and Environmental Protection II)

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24 pages, 8201 KiB

Open AccessArticle

Lifecycle Environmental Benefits with a Hybrid Electric Propulsion System Using a Control Algorithm for Fishing Boats in Korea

by Seongwan Kim, Hyeonmin Jeon, Chybyung Park and Jongsu Kim

J. Mar. Sci. Eng. 2022, 10(9), 1202; https://doi.org/10.3390/jmse10091202 - 27 Aug 2022

Cited by 6 | Viewed by 2579

Abstract

In Korea, fishing boats account for 65,452 out of 71,174 coastal ships, and aging ships are a leading cause of environmental problems and economic loss. To solve this problem, the government has enacted a policy to promote the development and distribution of environmental [...] Read more.

In Korea, fishing boats account for 65,452 out of 71,174 coastal ships, and aging ships are a leading cause of environmental problems and economic loss. To solve this problem, the government has enacted a policy to promote the development and distribution of environmental vessels. Electric propulsion systems and hybrid systems are suggested as alternatives. However, to study whether this hybrid system is environmentally friendly, a system for measuring the performance of conventional diesel-powered ships was developed and measured. A case study applying the battery hybrid system was analyzed through a Matlab/Simulink simulation, and the effect of reducing the carbon dioxide emissions by 7.6% was verified. In addition, comparing with a case where the load-sharing optimal control was introduced, we proved that the carbon dioxide reduction with the controller was 10.7%. By applying the results of this study to various countries with different fuel production processes through the LCA technique, it was confirmed that the battery hybrid system is eco-friendly from the energy production stage, rather than unconditionally, according to the national power production method. Additional research is needed to reflect the aging trend of the entire fleet and to create a detailed category classification through future research. Full article

(This article belongs to the Special Issue Marine Alternative Fuels and Environmental Protection II)

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29 pages, 9452 KiB

Open AccessArticle

Prediction of Emission Characteristics of Generator Engine with Selective Catalytic Reduction Using Artificial Intelligence

by Min-Ho Park, Chang-Min Lee, Antony John Nyongesa, Hee-Joo Jang, Jae-Hyuk Choi, Jae-Jung Hur and Won-Ju Lee

J. Mar. Sci. Eng. 2022, 10(8), 1118; https://doi.org/10.3390/jmse10081118 - 13 Aug 2022

Cited by 2 | Viewed by 2223

Abstract

Eco-friendliness is an important global issue, and the maritime field is no exception. Predicting the composition of exhaust gases emitted by ship engines will be of consequence in this respect. Therefore, in this study, exhaust gas data were collected from the generator engine [...] Read more.

Eco-friendliness is an important global issue, and the maritime field is no exception. Predicting the composition of exhaust gases emitted by ship engines will be of consequence in this respect. Therefore, in this study, exhaust gas data were collected from the generator engine of a real ship along with engine-related data to predict emission characteristics. This is because installing an emission gas analyzer on a ship has substantial economic burden, and, even if it is installed, the accuracy can be increased by a virtual sensor. Furthermore, data were obtained with and without operating the SCR (often mounted on ships to reduce NOx), which is a crucial facility to satisfy environment regulation. In this study, four types of datasets were created by adding cooling and electrical-related variables to the basic engine dataset to check whether it improves model performance or not; each of these datasets consisted of 15 to 26 variables as inputs. CO₂ (%), NOx (ppm), and tEx (°C) were predicted from each dataset using an artificial neural network (ANN) model and a support vector machine (SVM) model with optimal hyperparameters selected by trial and error. The results confirmed that the SVM model performed better on smaller datasets, such as the one used in this study compared to the ANN model. Moreover, the dataset type, DaCE, which had both cooling and electrical-related variables added to the basic engine dataset, yielded the best overall prediction performance. When the performance of the SVM model was measured using the test data of a DaCE on both no-SCR mode and SCR mode, the RMSE (R²) of CO₂ was between 0.1137% (0.8119) and 0.0912% (0.8975), the RMSE (R²) of NOx was between 17.1088 ppm (0.9643) and 13.6775 ppm (0.9776), and the RMSE (R²) of tEx was between 4.5839 °C (0.8754) and 1.5688 °C (0.9392). Full article

(This article belongs to the Special Issue Marine Alternative Fuels and Environmental Protection II)

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17 pages, 3975 KiB

Open AccessArticle

Effectiveness of the Speed Reduction Strategy on Exhaust Emissions and Fuel Oil Consumption of a Marine Generator Engine for DC Grid Ships

by Van Chien Pham, Hanseok Kim, Jae-Hyuk Choi, Antony J. Nyongesa, Jongsu Kim, Hyeonmin Jeon and Won-Ju Lee

J. Mar. Sci. Eng. 2022, 10(7), 979; https://doi.org/10.3390/jmse10070979 - 17 Jul 2022

Cited by 6 | Viewed by 2131

Abstract

Recent developments in power electronics, energy storage systems, and renewable energy; increased market demands for more efficient and cleaner electric power to meet stricter environmental regulations; and development in gigawatt (GW)-class DC (direct current) transmission systems for transmission of greater power over longer [...] Read more.

Recent developments in power electronics, energy storage systems, and renewable energy; increased market demands for more efficient and cleaner electric power to meet stricter environmental regulations; and development in gigawatt (GW)-class DC (direct current) transmission systems for transmission of greater power over longer distances than similar alternative current (AC) systems, have supported the development of the DC grid, making it a promising solution for both the onshore and offshore industries. This paper presents an experimental study on the effectiveness of an engine speed reduction strategy on exhaust gas emission and fuel consumption when applied to a 4-stroke generator engine equipped with a cam-driven plunger diesel injection system. The experiments were performed on an 8-cylinder V-type 4-stroke generator engine installed in the MASTC laboratory, which is the only demonstration testbed for the ship’s electric propulsion system in Korea. Experimental results showed that fuel consumption decreased, but emission mass fraction in exhaust gas increased when maintaining engine power while reducing engine speed. This study has shown economic benefits in reducing fuel consumption, but incurred penalties for the emission performance of 4-stroke generator engines equipped with cam-driven plunger diesel injection systems when applying the engine speed reduction strategy. Full article

(This article belongs to the Special Issue Marine Alternative Fuels and Environmental Protection II)

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12 pages, 2108 KiB

Open AccessArticle

Effect of Ammonia Addition on the Ignition Delay Mechanism of Methyl Decanoate

by Ye Qiu, Haijun Wei, Daping Zhou and Jingming Li

J. Mar. Sci. Eng. 2022, 10(7), 922; https://doi.org/10.3390/jmse10070922 - 3 Jul 2022

Cited by 1 | Viewed by 1510

Abstract

In this study, the effect of mixing a small amount of ammonia on the ignition delay time of methyl decanoate under different conditions was studied from the perspective of the combustion mechanism. The effect of adding ammonia on the ignition delay time of [...] Read more.

In this study, the effect of mixing a small amount of ammonia on the ignition delay time of methyl decanoate under different conditions was studied from the perspective of the combustion mechanism. The effect of adding ammonia on the ignition delay time of methyl decanoate at different pressures and temperatures was studied by means of simulation calculations and numerical comparison. Integrating the detailed mechanism and reaction path of methyl decanoate, the sensitivity of the ignition delay time was investigated. Analyses of the ignition delay time and rate of production were conducted to explore the transformation and influence of ammonia on the oxidation/decomposition process of the main elementary reaction during the ignition of methyl decanoate. The research illustrated that the ignition delay time of methyl decanoate increased with the number of moles of mixed ammonia at a certain temperature range, and in the negative temperature coefficient region, the effect of ammonia on the ignition delay time was the greatest. In addition, the susceptibility and yield analysis of methyl decanoate showed that the addition of ammonia had a weakening effect on the elementary reactions that originally promoted and inhibited methyl decanoate, and its consumption and production rates were reduced. Full article

(This article belongs to the Special Issue Marine Alternative Fuels and Environmental Protection II)

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17 pages, 3583 KiB

Open AccessArticle

Characteristics of Economic and Environmental Benefits of Shore Power Use by Container-Ship Size

by Kyunghwan Kim

J. Mar. Sci. Eng. 2022, 10(5), 622; https://doi.org/10.3390/jmse10050622 - 2 May 2022

Cited by 5 | Viewed by 2945

Abstract

To combat climate change, efforts to reduce greenhouse gas (GHG) emissions are being made in all industries. The shipping sector is also one of the industries that emits GHG, including carbon. One way to reduce GHG emissions in the shipping sector is to [...] Read more.

To combat climate change, efforts to reduce greenhouse gas (GHG) emissions are being made in all industries. The shipping sector is also one of the industries that emits GHG, including carbon. One way to reduce GHG emissions in the shipping sector is to use shore power (SP) rather than auxiliary engines during berthing. Port authorities are actively expanding SP facilities because it is possible to achieve the long-term goals of environmental benefits and green ports. However, the low economic feasibility of SP is a stumbling block for ship operators. Therefore, in this study, an economic analysis of SP use was conducted by container-ship size from the perspective of ship operators in consideration of benefits from differences in fuel oil and electricity prices, benefits through carbon emission reduction, and incentives from the port authorities. The result of the analysis showed that the benefit from the price of oil as well as the converted benefit from carbon emission reduction increased according to the size of the vessels. The economic analysis of a single port confirmed that small ships providing feeder services presented economic feasibility due to low installation costs and increased number of calls, while insufficient economic feasibility was presented for large ships above the old Panamax class due to the increased costs for installation. However, economic feasibility differs widely depending on whether port incentives are provided, and it was estimated that even large ships will be able to secure the economic feasibility of using SP if additional calls are made to ports that provide similar policy advantages. Full article

(This article belongs to the Special Issue Marine Alternative Fuels and Environmental Protection II)

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30 pages, 6689 KiB

Open AccessArticle

Comparative Analysis on AC and DC Distribution Systems for Electric Propulsion Ship

by Seongwan Kim and Hyeonmin Jeon

J. Mar. Sci. Eng. 2022, 10(5), 559; https://doi.org/10.3390/jmse10050559 - 20 Apr 2022

Cited by 4 | Viewed by 3740

Abstract

Decarbonization is an ongoing issue in the shipping industry, and electric propulsion systems are being proposed as alternative solutions to satisfy this requirement. To answer the fundamental questions of “Are electric propulsion systems the green solution?” and “Can DC distribution systems contribute to [...] Read more.

Decarbonization is an ongoing issue in the shipping industry, and electric propulsion systems are being proposed as alternative solutions to satisfy this requirement. To answer the fundamental questions of “Are electric propulsion systems the green solution?” and “Can DC distribution systems contribute to the decarbonization in shipping?”, this paper analyzed DC distribution system electrical characteristics, economic feasibility, and environmental evaluation for a full-scale AC-DC hybrid distribution electric propulsion system facility. By applying the actual ship’s operating profile as inputs, a DC distribution system with an active front end rectifier and a variable speed generator engine was proven to guarantee the same electric stability as the conventional AC distribution system. The life cycle assessment results achieved economic and life cycle environmental benefits of about 10% (8.9% for Case 1 and 12.4% for Case 2). These research findings offer meaningful insights into the DC distribution system to minimize fuel consumption and emissions toward cleaner shipping. Full article

(This article belongs to the Special Issue Marine Alternative Fuels and Environmental Protection II)

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24 pages, 10524 KiB

Open AccessArticle

Explosion Characteristics of Hydrogen Gas in Varying Ship Ventilation Tunnel Geometries: An Experimental Study

by Soung Woo Park, Jeong Hwan Kim and Jung Kwan Seo

J. Mar. Sci. Eng. 2022, 10(4), 532; https://doi.org/10.3390/jmse10040532 - 12 Apr 2022

Cited by 10 | Viewed by 3423

Abstract

Hydrogen is widely regarded as a key element of prospective energy solutions for alleviating environmental emission problems. However, hydrogen is classified as a high-risk gas because of its wide explosive range, high overpressure, low ignition energy, and fast flame propagation speed compared with [...] Read more.

Hydrogen is widely regarded as a key element of prospective energy solutions for alleviating environmental emission problems. However, hydrogen is classified as a high-risk gas because of its wide explosive range, high overpressure, low ignition energy, and fast flame propagation speed compared with those of hydrocarbon-based gases. In addition, deflagration can develop into detonation in ventilation or explosion guide tunnels if explosion overpressure occurs, leading to the explosion of all combustible gases. However, quantitative evidence of an increase in the explosion overpressure of ventilation tunnels is unavailable because the explosive characteristics of hydrogen gas are insufficiently understood. Therefore, this study investigated an explosion chamber with the shape of a ventilation pipe in a ship compartment. The effect of tunnel length on explosion overpressure was examined experimentally. For quantitative verification, the size of the hydrogen gas explosion overpressure was analyzed and compared with experimental values of hydrocarbon-based combustible gases (butane and LPG (propane 98%)). The experimental database can be used for explosion risk analyses of ships when designing ventilation holes and piping systems and developing new safety guidelines for hydrogen carriers and hydrogen-fueled ships. Full article

(This article belongs to the Special Issue Marine Alternative Fuels and Environmental Protection II)

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