Ammonia-based Solid Oxide Fuel Cell for zero emission maritime power: a case study

Implementing environmentally friendly fuels and high efficiency propulsion technologies to replace the Internal Combustion Engine (ICE) fueled by fossil fuels such as Heavy Fuel Oil (HFO) and Marine Gas Oil (MGO) on board ships represents an attractive solution for maritime power. In this context, fuel cells can play a crucial role, thanks to their high energy efficiency and ultra-low to zero criteria pollutant emissions and environmental impact. This paper performs the technical feasibility analysis for replacing the conventional diesel engine powertrain on board a commercial vessel with an innovative system consisting of ammonia-fuel-based Solid Oxide Fuel Cell (SOFC) technology. Taking into account the size of the diesel engines installed on board and the typical cruise performed by the commercial vessel, the ammonia consumption, as well as the optimal size of the innovative propulsion system have been assessed. In particular, the SOFC powertrain is sized at the same maximum power output as the main reference diesel engine. The mass and energy balances of the ammonia-based SOFC system have been performed in Aspen PlusTM environment. The gravimetric (kWh kg−1) and volumetric (kWh m−3) energy density features of the ammonia storage technology as well as the weight and volume of the proposed propulsion system are evaluated for verifying the compliance with the ship’s weight and space requirements. Results highlight that the proposed propulsion system involves an increase in weight both in the engine room and in the fuel room compared to the diesel engine and fuel. In particular, a cargo reduction of about 2.88% is necessary to fit the ammonia-based SOFC system compared to the space available in the reference diesel-fueled ship.

Deviations and errors review on measuring and calculating heavy fuel oil consumption and fuel stock onboard vessels equipped with volumetric fuel consumption flowmeters

A common way of measuring heavy fuel oil consumption on board a vessel is to use volumetric fuel flow meters installed at fuel systems inlets for each of the major fuel consumers. At each stage of the fuel processing cycle, certain mass fuel losses or deviations and calculation errors occur that are not counted accurately into fuel consumption figures. The goal of this paper is to identify those fuel mass losses and measuring/calculating errors and perform their quantitative numerical analysis based on actual data. Fuel mass losses defined as deviations identified during the fuel preparation process are evaporation of volatile organic compounds, water drainage, fuel separation, and leakages while errors identified are flow meter accuracy and volumetric/mass flow conversion accuracy. By utilizing statistical analysis of obtained data from engine logbook extracts from three different ships numerical models were generated for each fuel mass loss point. Measuring errors and volumetric/mass conversion errors are numerically analyzed based on actual equipment and models used onboard example vessels. By computational analysis of the obtained models, approximate percentage losses and errors are presented as a fraction of fuel quantity on board or as a fraction of fuel consumed. Those losses and errors present between 0,001% and 5% of fuel stock or fuel consumption figures for each identified loss/error point. This paper presents a contribution for more accurate heavy fuel oil consumption calculation and consequently accurate declaration of remaining fuel stock onboard. It also presents a base for possible further research on the possible influence of fuel grade, fuel water content on the accuracy of consumption calculation.

A Comparison of Alternative Fuels for Shipping in Terms of Lifecycle Energy and Cost

Decarbonization of the shipping sector is inevitable and can be made by transitioning into low- or zero-carbon marine fuels. This paper reviews 22 potential pathways, including conventional Heavy Fuel Oil (HFO) marine fuel as a reference case, “blue” alternative fuel produced from natural gas, and “green” fuels produced from biomass and solar energy. Carbon capture technology (CCS) is installed for fossil fuels (HFO and liquefied natural gas (LNG)). The pathways are compared in terms of quantifiable parameters including (i) fuel mass, (ii) fuel volume, (iii) life cycle (Well-To-Wake—WTW) energy intensity, (iv) WTW cost, (v) WTW greenhouse gas (GHG) emission, and (vi) non-GHG emissions, estimated from the literature and ASPEN HYSYS modelling. From an energy perspective, renewable electricity with battery technology is the most efficient route, albeit still impractical for long-distance shipping due to the low energy density of today’s batteries. The next best is fossil fuels with CCS (assuming 90% removal efficiency), which also happens to be the lowest cost solution, although the long-term storage and utilization of CO2 are still unresolved. Biofuels offer a good compromise in terms of cost, availability, and technology readiness level (TRL); however, the non-GHG emissions are not eliminated. Hydrogen and ammonia are among the worst in terms of overall energy and cost needed and may also need NOx clean-up measures. Methanol from LNG needs CCS for decarbonization, while methanol from biomass does not, and also seems to be a good candidate in terms of energy, financial cost, and TRL. The present analysis consistently compares the various options and is useful for stakeholders involved in shipping decarbonization.

THE APPLICATION OF FUZZY AHP – VIKOR HYBRID METHOD TO INVESTIGATE THE STRATEGY FOR REDUCING AIR POLLUTION FROM DIESEL POWERED VESSELS

The negative impact of air pollution on human health had become a vital issue as a result of the increasing use of fossil fuels in recent years. In this context, maritime transportation is one of the most contaminant sectors by using much more fossil fuels. Ships which have a major role in maritime transport, directly affect human health via its emissions, especially in marine areas close to the land such as around the ports, canals, and straits. In this study, strategies were gathered by evaluating International Maritime Organization (IMO) regulations, European Union (EU) recommendations and the applications of the ship owner companies to reduce air pollution stem from ships, and considering the priority perception of these strategies, the effect level of the strategies at the marine areas where ships are approaching the land was analysed by the Fuzzy Analytic Hierarchy Process-Visekriterijumska Optimizacija I Kompromisno Resenje (AHP- VIKOR) hybrid method. As a result of the study, the most effective strategies appeared as “Forbiddance of Heavy Fuel Oil (HFO) usage on Ships” and “Detection of Low Sulphur Fuel Usage by the help of Remote Detector Systems”, and it was seen that these strategies would be most effective in canal or strait passing of the ships. It was also revealed that the relevant expert opinions and IMO regulations meshed together, and it was pointed out the applications for increasing fuel quality.

ANALISIS PENGARUH WAKTU DAN JARAK PERJALANAN KAPAL TERHADAP BIAYA LOW SULPHUR SURCHARGE

The danger of ship emission caused by HFO (Heavy Fuel Oil) fuel type has become a serious matter due to its high containment of sulphur as much as 3.50% m/m. The IMO (International Maritime Organization) took action on this problem by releasing new regulation to limit sulphur in the ship fuel as low as 0.50% m/m. This regulation leads to an additional tariff called the LSS (Low Sulphur Surcharge). As an impact, shipping companies charge this fee to customers and ocean freight forwarders, hence there is an increase of the total shipping charges. Meanwhile, the dominant variable which determines the LSS charge amount is not yet known, so it is still uninformative for the public and the academic field. The purpose of this study is to analyse which variable gives the most influence on the amount of the LSS tariff. By using multiple linear regression method, the study finds that the shipping distance variable is the dominant variable with a contribution value of 86.48% and has positive relationship with the LSS tariff. On the other hand, though the voyage time also has influence on the tariff, the effect is weak and it shows negative relationship with the LSS tariff.

Numerical simulation of cavitating flow in maritime high-pressure direct fuel injection nozzles and assessment of cavitation-erosion damage

The internal flow of Heavy Fuel Oil (HFO) in two maritime direct fuel injector nozzles is studied by 3D flow simulations for the assessment of erosion-sensitive wall regions. The nozzle geometries differ in number, diameter and inclination angle of holes as well as sac wall curvature. Long-term endurance experiments reveal characteristic damage locations for both nozzles. Simulations are performed by a compressible density-based flow solver with a barotropic cavitation model to capture shock wave dynamics. Real geometries and the entire injection cycle with time-dependent rail pressure and transient needle movement are considered. A statistical evaluation of individual collapsing voids in terms of their condensation rate yield an erosion probability that is compared against experimental damage locations. Due to the scatter in the values of viscosity of real fuels a viscosity variation is carried out, which shows that while a lower viscosity leads to a rise of erosion probability, the location of erosion-sensitive wall zones is not significantly changed. The analysis of 3D velocity and void field evolutions motivates the introduction of distinct injection sub-phases of the entire cycle. Erosion probability is separately evaluated within each sub-phase. By this simulation procedure, experimentally found erosion spots are associated with particular sub-phases and can be traced back to characteristic flow and void structures that are linked to particular nozzle geometry features.

Application of rapidly improving battery technology for direct electrification of intraregional container shipping

International maritime shipping—powered by heavy fuel oil—contributes 2.5%, 12%, and 13% of global anthropogenic CO2, SO2, and NOx emissions, respectively. The direct electrification of vessels has been underexplored as a low-emission option despite its considerable efficiency advantage over electrofuels such as green hydrogen and ammonia. Previous studies of ship electrification have relied on outdated battery cost and energy density values and have incorrectly assumed mechanical space to be a fixed technical variable. We show that with near-future battery prices of $100 kWh-1 the electrification of intraregional trade routes of less than 1,000 km is economically feasible with minimal impact to ship carrying capacity. Projected declines in battery price to $50 kWh-1 could improve this range to 5,000 km. We describe a pathway for the battery electrification of containerships within this decade that electrifies over 40% of global containership traffic, reduces CO2 emissions by 40% for US-based vessels, and mitigates the health impacts of air pollution on coastal communities.

Investigating the Compatibility of Various Components in Marine Low-Sulfur Fuel Oil by Molecular Dynamics Simulations

Asphaltene aggregation and precipitation are one of the major issues for marine low-sulfur fuel oil used on board. Many research studies have been carried out to investigate the aggregation behavior of asphaltene under different conditions, but the mechanism of asphaltene aggregation in low-sulfur fuel oil at the molecular level is still unclear. In this work, molecular dynamics (MD) simulations were performed to calculate the solubility parameters, intermolecular interaction energies, and radial distribution function (RDF) curves of each component in marine low-sulfur fuel oil to examine their mutual compatibility. Simulation results indicate that the solubility parameter of resin gains the highest value and it is close to asphaltene. The solubility parameters of aromatic, hexadecane, and saturate decrease successively. The interaction energy between resin and asphaltene molecules is higher than that between the same kind of molecules, which means that resin can inhibit the aggregation of asphaltene molecules. Typically, a light distillate component (hexadecane) is added to heavy fuel oil to yield low-sulfur oil, and our calculations reveal that this has a negative effect on asphaltene aggregation. Specifically, asphaltene is more likely to self-aggregate, as shown by the increase in peak height in the radial distribution function of the asphaltene-asphaltene pair. The findings of this study will provide theoretical support for the production of marine low-sulfur fuel.