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Modern marine power plants have been designed to improve the overall ship’s efficiency. This pushed the designers of marine machinery to search for unconventional fuels for these plants. During the previous years, diesel oil has been extensively used on-board ships. Due to the high price of light diesel oil and the environmental problems resulting...
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... to avoid pre-ignition. The challenge with DI-H 2 ICE operation is that in-cylinder injection requires hydrogen-air mixing in a very short time. iv. H 2 ICE-electric hybrid: A hybrid-electric version of an H 2 ICE offers the potential for improved efficiencies and reduced emissions without the need for aftertreatment. In a hybrid electric system, the ICE operates either in series or parallel with an electric motor. Hydrogen is suggested to be used for the existing diesel engines to minimize the cost as much as possible. The suggested engine will be operated with hydrogen being directly injected into the cylinders, as shown in Figure 3. To initiate the combustion process, low energy sparks will be needed to avoid using amounts of diesel fuel. Fuel pumps and sparks are to be electronically controlled (camless engines) to ensure the optimum performance at various operating conditions, as shown in Figure 4. One of the main problems related to the adoption of hydrogen for internal combustion engines is the engine knocking that arises due to malfunction of air fuel ratio and intake ...
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Hydrogen can be regarded as the most promising clean energy in the 21st century. Up to now, hydrogen production is still a challenge for scientists. With further research, many theories of hydrogen generation have been delivered successfully. Ni-based catalysts hydrolyze ammonia borane can be simple and effective. Ammonia borane (H3NBH3, AB) has th...
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... In particular, the sustainability of compression ignition engines can be improved considerably [28,29]. Therefore, to mainly reduce CH 4 in the exhaust, the maritime sector is going down the same path [30]. Consequently, some research attempts are directing their efforts towards the study of diesel and hydrogen combustion in marine engines for dual fuel applications. ...
... 548 C. Dere Hydrogen implementation alternatives to internal combustion engines such as port injection and direct injection (Serrano et al. 2021) have their own advantages and disadvantages. For instance, while pre-ignition and knocking can be overcame by direct injection, direct injection has a limited time to fuel-air mixing (Seddiek et al. 2015). ...
... Hydrogen has different operational parameters in that the efficiency of the engine differs for the same output powers as higher combustion temperatures, lower mean effective pressures, and higher exhaust temperature values compared to that of the diesel engine (Seddiek et al. 2015). ...
... In the research of a RORO ship engine, the hydrogen operation efficiency could be achieved around 32% since the cooling loses in the hydrogen engine is higher (Seddiek et al. 2015). Additionally, it was reported that the operational load affects cooling loses significantly, while lean combustion operation has lower cooling loss than near-stoichiometric combustions (Shudo, et al. 2001). ...
... It has been used to power several types of fuel cells (Bassam et al., 2017;Horvath et al., 2018;Welaya et al., 2011). Seddiek et al. (2015) stated the availability of using hydrogen in the marine engine while it is essential to tune the engine to avoid knocking as well as provide sufficient higher rates of water for cooling than in diesel oil to avoid high temperatures. The hydrogen engine has lower thermal efficiency, mean effective pressure and fuel consumption compared to the diesel engine. ...
This paper presents a comprehensive review of the current regulations and the various technologies as well as the decision support methods for each technology the maritime industry considers to ensure the fleet's sustainability. It covers the period between 2010 and 2022, emphasizing the last four years. It shows the impact of each technology on the reduction of ship resistance and the energy required on board, affecting the amount of fuel consumption and avoiding the transportation of harmful species around the world to achieve a smooth transition towards green shipping by improving the fleet's energy efficiency and achieving the goals of the 2050 plan. The paper covers five main topics: hull design, propulsion systems, new clean fuels and treatment systems, power systems and ship operation; and each topic has different technologies included. This study's findings contribute to mapping the scientific knowledge of each technology in the maritime field, identifying relevant topic areas, visualising the links between the topics, and recognising research gaps and opportunities. This review helps to present holistic approaches in future research supporting the cooperation between maritime industry stake-holders to provide more realistic solutions toward sustainability.
... The use of green power for electrolytic water production of green hydrogen is expected to achieve commercial adoption. Hydrogen internal combustion engines [138] and hydrogen fuel cells [139] help ships achieve cleaner and longer-distance transportation. The production or final use of green hydrogen may not be the bottleneck for the application of green hydrogen to ships. ...
The shipping industry has reached a higher level of maturity in terms of its knowledge and awareness of decarbonization challenges. Carbon-free or carbon-neutralized green fuel, such as green hydrogen, green ammonia, and green methanol, are being widely discussed. However, little attention has paid to the green fuel pathway from renewable energy to shipping. This paper, therefore , provides a review of the production methods for green power (green hydrogen, green ammonia , and green methanol) and analyzes the potential of green fuel for application to shipping. The review shows that the potential production methods for green hydrogen, green ammonia, and green methanol for the shipping industry are (1) hydrogen production from seawater electrolysis using green power; (2) ammonia production from green hydrogen + Haber-Bosch process; and (3) meth-anol production from CO2 using green power. While the future of green fuel is bright, in the short term, the costs are expected to be higher than conventional fuel. Our recommendations are therefore as follows: improve green power production technology to reduce the production cost; develop electrochemical fuel production technology to increase the efficiency of green fuel production; and explore new technology. Strengthening the research and development of renewable energy and green fuel production technology and expanding fuel production capacity to ensure an adequate supply of low-and zero-emission marine fuel are important factors to achieve carbon reduction in shipping.
... Engine knock is a major issue when using hydrogen in internal combustion engines, much like with natural gas. For an engine to run without knocking, the air-fuel ratio and intake temperature have been recognized as the key causes of the issue [55]. Most crucially, in order to build a supply chain and meet the challenging CO2 reduction objectives in the marine industry, there must be a global usage and demand for hydrogen fuel. ...
The application of newly available technologies in the green maritime sector is difficult due to conflicting requirements and the inter-relation of different ecological, technological and economical parameters. The governments incentivize radical reductions in harmful emissions as an overall priority. If the politics do not change, the continuous implementation of stricter government regulations for reducing emissions will eventually result in the mandatory use of, what we currently consider, alternative fuels. Immediate application of radically different strategies would significantly increase the economic costs of maritime transport, thus jeopardizing its greatest benefit: the transport of massive quantities of freight at the lowest cost. Increased maritime transport costs would immediately disrupt the global economy, as seen recently during the COVID-19 pandemic. For this reason, the industry has shifted towards a gradual decrease in emissions through the implementation of “better” transitional solutions until alternative fuels eventually become low-cost fuels. Since this topic is very broad and interdisciplinary, our systematic overview gives insight into the state-of-the-art available technologies in green maritime transport with a focus on the following subjects: (i) alternative fuels; (ii) hybrid propulsion systems and hydrogen technologies; (iii) the benefits of digitalization in the maritime sector aimed at increasing vessel efficiency; (iv) hull drag reduction technologies; and (v) carbon capture technologies. This paper outlines the challenges, advantages and disadvantages of their implementation. The results of this analysis elucidate the current technologies’ readiness levels and their expected development over the coming years.
... These fuels do not contain carbon nor sulfur and thus their combustion does not generate carbon emissions (CO 2 , CO, HC, soot), or SO x . Despite the good performance and low emissions of hydrogen, its storage is too complicated to be employed in marine engines [5]. Nevertheless, storage and distribution of ammonia are much easier. ...
... The chemical reactions were treated through additional equations. Given a set of N species and m reactions, Equation (4), the local mass fraction of each species, f k , can be expressed by Equation (5). ...
Nowadays, the environmental impact of shipping constitutes an important challenge. In order to achieve climate neutrality as soon as possible, an important priority consists of progressing on the decarbonization of marine fuels. Free-carbon fuels, used as single fuel or in a dual-fuel mode, are gaining special interest for marine engines. A dual fuel ammonia-diesel operation is proposed in which ammonia is introduced with the intake air. According to this, the present work analyzes the possibilities of ammonia in marine diesel engines. Several ammonia-diesel proportions were analyzed, and it was found that when the proportion of ammonia is increased, important reductions of carbon dioxide, carbon monoxide, and unburnt hydrocarbons are obtained, but at the expense of increments of oxides of nitrogen (NOx), which are only low when too small or too large proportions of ammonia are employed. In order to reduce NOx too, a second ammonia injection along the expansion stroke is proposed. This measure leads to important NOx reductions.
... These fuels do not contain carbon nor sulfur and thus their combustion does not generate carbon emissions (CO 2 , CO, HC, soot), or SO x . Despite the good performance and low emissions of hydrogen, its storage is too complicated to be employed in marine engines [5]. Nevertheless, storage and distribution of ammonia are much easier. ...
... The chemical reactions were treated through additional equations. Given a set of N species and m reactions, Equation (4), the local mass fraction of each species, f k , can be expressed by Equation (5). ...
... In the marine field, marine engines are relevant sources of particulate matter (PM), NOx, and other undesirable substances such as SOx, CO2, CO, HC, etc. [1][2][3][4][5][6]. Among those substances, NOx and SOx are currently receiving special attention due to the increasingly strict limitations imposed by the IMO (International Maritime Organization) and other organisms [7][8][9][10][11][12][13][14][15][16]. In recent years, the need to reduce NOx emissions led to several measures. ...
The present manuscript describes a computational model employed to characterize the performance and emissions of a commercial marine diesel engine. This model analyzes several pre-injection parameters, such as starting instant, quantity, and duration. The goal is to reduce nitrogen oxides (NOx), as well as its effect on emissions and consumption. Since some of the parameters considered have opposite effects on the results, the present work proposes a MCDM (Multiple-Criteria Decision Making) methodology to determine the most adequate pre-injection configuration. An important issue in MCDM models is the data normalization process. This operation is necessary to convert the available data into a non-dimensional common scale, thus allowing ranking and rating alternatives. It is important to select a suitable normalization technique, and several methods exist in the literature. This work considers five well-known normalization procedures: linear max, linear max-min, linear sum, vector, and logarithmic normalization. As to the solution technique, the study considers three MCDM models: WSM (Weighted Sum Method), WPM (Weighted Product Method) and TOPSIS (Technique for Order Preference by Similarity to Ideal Solution). The linear max, linear sum, vector, and logarithmic normalization procedures brought the same result: -22º CA ATDC pre-injection starting instant, 25% pre-injection quantity and 1-2º CA pre-injection duration. Nevertheless, the linear max min normalization procedure provided a result, which is different from the others and not recommended.
... Particularly, NO x and SO x are considered especially damaging [1][2][3][4]. In the marine field, even stricter limitations imposed by the IMO (International Maritime Organization) and other organizations regulate emissions from ships [5][6][7][8]. Regarding SO x , the maximum content in the fuels is limited for ships that do not have any post-treatment device. Regarding NO x , IMO establishes even stricter maximum emissions depending on the engine and region. ...
The present work proposes several modifications to optimize both emissions and consumption in a commercial marine diesel engine. A numerical model was carried out to characterize the emissions and consumption of the engine under several performance parameters. Particularly, five internal modifications were analyzed: water addition; exhaust gas recirculation; and modification of the intake valve closing, overlap timing, and cooling water temperature. It was found that the result on the emissions and consumption presents conflicting criteria, and thus, a multiple-criteria decision-making model was carried out to characterize the most appropriate parameters. In order to analyze a high number of possibilities in a reasonable time, an artificial neural network was developed.
... Hydrogen fuel can also be used directly in IC engines, but storage problems with low-energy density and safety problems are the main obstacle to adopt hydrogen as a widely used marine fuel (Seediek, Elgohary, and Ammar 2015). Hydrogen can be stored in compressed tanks (pressure between 350 and 700 bars) or in a liquefied state (cooled to cryogenic temperature of −253°C), and a direct injection of hydrogen into IC engine is considered to be the most acceptable option (Ahn et al. 2017). ...
... Hydrogen fuel supply system(Seediek, Elgohary, and Ammar 2015). ...
The maritime industry is becoming increasingly aware of the global environ-
mental impact of ships and is being forced, by international legislation, to
gradually reduce its emissions. International Maritime Organization conven-
tions and energy efficiency standards set challenges to shipping sector, to
ship owners and ship designers, and to offer propulsion concepts that will
effectively reduce or completely eliminate emission rates and increase
energy efficiency with acceptable technological costs and adjustment time.
New concepts include environmental-friendly fuels in existing propulsion
architecture, hybrid propulsion, and all-electric propulsion architecture with
the possible application of renewable energy sources, which are reviewed in
this paper. Each concept has advantages and disadvantages regarding
adjustment time, implementation cost and energy storage system capacity.
One of the main disadvantages for complete replacement of conventional
propulsion systems is the limited energy storage capacity of existing storage
devices, which would decrease the operational ability of the shipping sector
as a cheap transportation solution on the global market. Such problems and
unsolved environmental issues regarding the production and recycling of
energy storage devices are highlighted in this paper and must be further
developed. The main motivation for the paper's work is to offer a detailed
review of possible solutions for ship propulsion and to offer direction for
further research. This is obtained by applying a literature review method to
compare the advantages and disadvantages of each proposed solution. The
results are discussed in the last section of the paper with the final conclusion
that the internal combustion engines will not be completely replaced in the
shipping sector in terms of the next few decades but will be able to use
environmental-friendly fuels or fuels without a global carbon footprint. This
conclusion is the result of analyzing especially large ocean-going vessels with
very strong internal combustion engines. Such high power and energy
demand are not very easy to be replaced with alternative energy sources
or with all-electric ship solution without decreasing all other advantages of
merchant shipping sector. Forecasts of ambitious decarbonization scenarios
predict wide usage of carbon-neutral fuels in the late 2030s or mid-2040s and
Green House Gases reduction (in the range between 50% and 100%) in 2050,
which can be obtained by using enviromental-friendly fuels in existing
infrastructure. It is still hard to identify which carbon-neutral fuel will be
dominant, but e-ammonia, blue ammonia, bio-methanol, and hydrogen are
the most promising carbon-neutral fuels in the decarbonization path.
