Low Sulfur Fuel Oil Research Articles

Evaluating Environmental Impact and the Significance of Shipboard Carbon Capture and Storage for Emission Reduction in Maritime Sector

Abstract This study conducts Life Cycle Assessment (LCA) to evaluate the environmental impacts of Shipboard Carbon Capture & Storage (SCCS) across its entire lifecycle. It examines the full-spectrum carbon capture and storage effects from well-to-tank and tank-to-propeller for four types of marine fuels: Very Low Sulphur Fuel Oil (VLSFO), Marine Gas Oil (MGO), Liquefied Natural Gas (LNG), and Methanol. Additionally, the study examines the Energy Efficiency Existing Ship Index (EEXI) and Carbon Intensity Indicator (CII) of a current ocean-going container ship to quantify the potential benefits of SCCS in reducing ship carbon emissions. The results indicate that the application of SCCS can significantly reduce emissions from carbon-based fuels during ship operations. In particular, ships using VLSFO as fuel can achieve 61.0% reduction in emissions by installing SCCS. However, the application of SCCS leads to 7.8% increase in fuel consumption due to additional energy requirement. In addition, this study also found while fossil methanol reduces emissions during ship combustion, its life cycle emissions are 17.5%-19.6% higher than conventional fossil fuel due to production emissions. The overall SCCS has a positive impact on emission reduction for ships and is reflected in the improvements in EEXI and CII. With the implementation of SCCS, ships fuelled by VLSFO and MGO can remain compliant with IMO Greenhouse Gases emission strategy until 2030. For ships fuelled by LNG and Methanol, compliance can remain beyond 2030.

Factors affecting pedestrian-level ship pollution in port areas: CFD in the service of policy-making

Examining the impact of various factors associated with plume dispersion is essential for quantifying ship pollution in port areas, particularly adjacent to urban environments. This paper concerns the application of Computational Fluid Dynamics (CFD) modelling to study the effect of such factors on air pollution at the passenger port of Marseille, France. Pedestrian-level pollution maps are created for several emission scenarios involving variables such as wind conditions, docking location, emission reduction technology, different emission sources, as well as parameters related to the vessel. Depending on wind direction, docking location and vessel's engine power, different parts of the studied area are exposed to ship pollution. Within a typical examined range, funnel exhaust temperature, funnel height and wind speed deviate up to 78 %, 45 % and 59 % from the baseline scenario, respectively, indicating significant sensitivity of ship pollution to changes in these factors. The lower buoyancy effects of using a scrubber lead to a 17 % larger area exposed to increased ship pollution instead of using Ultra Low Sulphur Fuel Oil (ULSFO). Additionally, it is estimated that an individual vessel may contribute up to six times more to the NOx pollution of a roundabout located 800 m downwind, compared to the local road traffic. The current work can provide valuable information to various stakeholders such as port authorities, decision-makers, or even air quality modelers regarding the impact of shipping emissions on air pollution in port areas, constituting a useful assessment and advisory tool.

Scrubber installation of inland container ships: Discrepancy between government and carriers

Scrubbers are the commonly used green technologies for a ship to reduce sulfur emissions. Various speed adjustment behaviors would distort the cost and desulfurization efficiency of scrubbers for ships, which causes a discrepancy between the government and the carrier to install scrubbers. This paper addresses the issue by considering three speed adjustment behaviors: rigidity, partial flexibility, and full flexibility. Under rigid behavior, the carrier maintains a constant sailing speed when adopting low-sulfur fuel oil (LSFO) and installing a scrubber. Partially flexible behavior only involves speed adjustments when adopting LSFO, while fully flexible behavior includes speed adjustments when adopting LSFO and installing a scrubber. Our analysis indicates that scrubber installation consistently precedes adopting LSFO in speed. Full flexibility behavior is the least costly speed adjustment behavior, while partial flexibility behavior results in the lowest emissions. The investment discrepancy on scrubbers between the carrier and the government would occur on whether or not to install a scrubber and which level of the scrubber’s quality since the two parties are concerned about the sulfur emissions and cost, respectively. Government subsidies address these discrepancies, leading to improved emission reduction.

Heavy oil atmospheric residue: HDS performance and life test using ARDS catalysts system

The objective of this study is to evaluate the catalyst by introducing atmospheric residue of heavy crude (H-AR) that secures full comprehensive characteristics and converts into a petroleum product, namely low sulfur fuel oil (LSFO). Furthermore, to estimate the catalyst’s lifespan under hydroprocessing conditions by monitoring its deactivation rate and maintaining consistent sulfur in LSFO products through gradual increases in reaction temperature. Prior to the hydrotreating test, the heavy crude oil underwent desalting, dewatering, and atmospheric distillation to obtained atmospheric residue (H-AR, i.e., 350°C+) for use as feedstock. The pilot plant employed a catalyst system comprising both hydrodemetallization (HDM) and hydrodesulfurization (HDS) catalysts, distributed across two fixed-bed reactors. The results showed the lifespan approximately 3.0 months as a function of time-on-stream (TOS). The H-AR feed, with its high sulfur, metals, asphaltenes, and micro carbon residue (MCR) content, poses several challenges including carbon deposition at start of run (SOR). The observed deactivation rate is attributing to the feedstock’s poor quality and its impact associated deposition of coke and metals (V and Ni) deposition with TOS.

Effects on of Blended Biodiesel and Heavy Oil on Engine Combustion and Black Carbon Emissions of a Low-Speed Two-Stroke Engine

Abstract The effects of heavy fuel oil and biodiesel blends on engine combustion and emissions were studied in a marine two-stroke diesel engine. The engine was operated under propeller conditions using five different fuels with biodiesel blends of 10% (B10), 30% (B30), 50% (B50), and sulphur contents of 0.467% low sulphur fuel oil (LSFO) and 2.9% high sulphur fuel oil (HSFO). Tests have shown that using a biodiesel blend increases the engine fuel consumption due to its lower calorific value. Heavy fuel oil has a high Polycyclic aromatic hydrocarbons (PAH) content, which leads to higher exhaust temperatures due to severe afterburning in the engine. A comparison of engine soot emissions under different fuel conditions was carried out, and it was found that the oxygen content in biodiesel promoted the oxidation of soot particles during the combustion process, which reduced the soot emissions of biodiesel. Compared to HSFO, B10, B30, B50 and LSFO, the soot emission concentrations were reduced by 50.2%, 56.4%, 61% and 37.4%, respectively. In our experiments, the soot particles in the engine exhaust were sampled with a thermal float probe. Using Raman spectroscopy analysis, it was found that as the biodiesel ratio increased, the degree of carbonisation of the soot particles in the exhaust became less than that in the oxygenation process, resulting in a decrease in the degree of graphitisation.

Characterization of hydrocarbon degraders from Northwest Passage beach sediments and assessment of their ability for bioremediation.

Global warming-induced sea ice loss in the Canadian Northwest Passage (NWP) will result in more shipping traffic, increasing the risk of oil spills. Microorganisms inhabiting NWP beach sediments may degrade hydrocarbons, offering a potential bioremediation strategy. In this study, the characterization and genomic analyses of 22 hydrocarbon-biodegradative bacterial isolates revealed that they contained a diverse range of key alkane and aromatic hydrocarbon-degradative genes, as well as cold and salt tolerance genes indicating they are highly adapted to the extreme Arctic environment. Some isolates successfully degraded Ultra Low Sulfur Fuel Oil (ULSFO) at temperatures as low as -5°C and high salinities (3%-10%). Three isolates were grown in liquid medium containing ULSFO as sole carbon source over 3 months and variation of hydrocarbon concentration was measured at three time points to determine their rate of hydrocarbon biodegradation. Our results demonstrate that two isolates (Rhodococcus sp. R1B_2T and Pseudarthrobacter sp. R2D_1T) possess complete degradation pathways and can grow on alkane and aromatic components of ULSFO under Arctic conditions. Overall, these results demonstrate that diverse hydrocarbon-degrading microorganisms exist in the NWP beach sediments, offering a potential bioremediation strategy in the events of a marine fuel spill reaching the shores of the NWP.

Risk-based retrofitting analysis employing the carbon intensity indicator

The study employs a risk-based approach for ship propulsion system retrofitting analysis to reduce CO2 emissions and enhancing cost efficiency. The analysis is based on historical data from the EU-MRV database collected for ships operating in the Black Sea using the Carbon Intensity Indicator (CII). Based on the Attained CII/Required CII rate, four levels are identified as critical thresholds and analysed by the Weibull probabilistic model. Additionally, a cost-benefit analysis is performed, accounting for discounted costs related to the initially installed propulsion system supplied by Very Low Sulphur Fuel Oil (VLSFO) and the retrofitted system on Liquefied Natural Gas (LNG), including the cost of the fuel and taxes related to CO2, insurance, maintenance, interest rate, depreciation, resale, and loss of opportunity, conditional on the retrofitting consequences. The cost-benefit and associated risk-based retrofitting analyses are employed to identify the most appropriate retrofitting solution. The Weibull probabilistic model accounts for the enormous uncertainty and variation of the input parameters. The study demonstrates how the data can address critical issues such as condition-based time and the best ship age for retrofitting, accounting for the associated risk. An effort is made to define when to perform retrofitting, reaching a specific ship age accounting for the time needed for retrofitting.

Emission characteristics of naphthalene from ship exhausts under global sulfur cap

The global sulfur limit regulation mandates the use of 0.5 % low sulfur fuel oil (LSFO) to reduce emissions of sulfur oxides (SOx), nitrogen oxides (NOx), and particulate matter (PM). However, the addition of naphthalene (Nap) to LSFO to stabilize its quality has led to an increase in polycyclic aromatic hydrocarbons (PAHs), with Nap being the main pollutant. This study investigates the effects of Nap in ship exhaust by analyzing the emission concentrations of volatile organic compounds (VOCs) and Nap in the exhaust of 16 ships, including 2 container ships, 6 bulk carriers, 1 tanker, 2 ferries, 3 fishing vessels, and 2 harbor crafts, based on USEPA method TO-15A. The results show that the percentage of Nap emissions in the exhaust gases of the 16 ship engines ranged from 77 % to 97 % of the total volatile organic compound (TVOC). The Nap concentration in the exhaust of fishing vessels, tanker, and harbor craft exceeded the occupational exposure limit of 50,000 μg/m3, with fishing vessels having the highest TVOC and Nap concentrations. The enhanced Nap emission in the air degrades air quality in port cities and poses an obvious potential public health risk. While the benefits of the global sulfur cap are being secured, additional efforts should be made to reduce the undetected side effects. Alternative stabilizers of LSFO should be considered, or Nap emission control should be boosted to mitigate the potential negative impact on harbor air quality.

Investigation on the applicability of parameters identification of marine diesel engine SCR kinetic model based on Discrete-Grid algorithm

Selective catalytic reduction (SCR) technology is the most widely used denitrification method in industry. However, the calibration of its kinetic model is very problematic due to the large number of parameters involved and the nonlinear characteristics, especially for the undesired reactions such as formation-decomposition of ammonium nitrate (AN), ammonium sulfate (AS), ammonium bisulfate (ABS), etc. In this paper, the synthetic gas test bench and the SCR system of WD10 marine diesel engine burning high-sulfur fuel oil (HSFO) and low-sulfur fuel oil (LSFO) are taken as the research objects. Firstly, based on the experimental data obtained from the synthetic gas test bench, the pre-exponential multiplier and activation energy of each reaction were identified using the Discrete-Grid algorithm. In this work, considering that the production of N2O, SO3, AN, AS, and ABS in the undesired reactions is very low, not on the same order of magnitude as that of NO and NH3, it is easy to overlook their reaction characteristics in the optimization process. We have adopted an approach that amplifies the error between the predicted concentration and the observed concentration of the species to solve this problem. Secondly, a detailed and complete SCR kinetic model was constructed. Finally, with the parameter identification results obtained from the synthesis gas bench as initial values, all the kinetic parameters of the WD10 marine engine SCR model was calibrated simultaneously using the Discrete-Grid algorithm. The results showed that the SCR kinetic model derived from the synthetic gas test bench was suitable for the real marine engine SCR system when the range of temperature and space velocity (SV) of the synthetic gas bench test is similar to that of the marine SCR system.

A stochastic approach for economic valuation of alternative fuels: The case of container ship investments

With unpredictable climate policies and fuel technology developments, the maritime industry faces significant uncertainties. This study presents a stochastic approach to assess investments in container ships powered by three types of fuel in the context of carbon pricing: Low sulfur fuel oil (LSFO), liquefied natural gas (LNG), and ammonia. To analyse uncertainty, we model carbon permit and bunker prices stochastically, and presented probabilistic functions of the net present value (NPV) and the energy density adjusted levelised cost of energy (LCOE). The results suggest that with carbon pricing the chance of LNG to be more profitable than LSFO increases, while the ammonia-fuelled ship exhibits the least expected NPV with the widest distribution in all carbon pricing scenarios. Fossil fuels are more advantageous in generating a lower cost of power, both with and without carbon pricing. Consequently, our findings suggest that carbon pricing alone will not be sufficient to facilitate a transition to ammonia. Furthermore, various measures to mitigate the uncertainties associated with ammonia fuel would be required, including the development of infrastructure to ensure a stable fuel supply.

Preparation and properties of graphene composite lubricants additive used for cylinder liner in marine diesel burning low sulfur fuel oil

In recent years, abnormal wear issues have emerged in cylinder liner-piston rings (CL-PRs) in marine diesels that burn low-sulfur fuel oils (LSFO). To address this issue, a graphene-attapulgite composite additive was prepared and characterized as detailed in this report. Then, the tribological properties and corrosion resistance of this graphene-attapulgite were investigated when it was used at various concentrations as a multifunctional composite lubricant additive in simulated LSFO lubrication conditions. It was found that the appropriate concentration of the additive in a lubricant produced excellent anti-friction and anti-wear properties. This was when the additive was at 0.25 wt% concentration in normal lubricating conditions, where the friction coefficient and wear mass loss were reduced by 22.7% and 44.1%, respectively. Additionally, the impermeability of the graphene additive was found to improve the corrosion resistance of the lubricant. These findings revealed the mechanism of the graphene-attapulgite additive for friction reduction and corrosion resistance of cylinder liner in simulated LSFO lubrication conditions, which provided an inhibition method to prevent abnormal wear of cylinder liner in marine diesel burning LSFO.

Evaluation of biofuel effect on performance & emissions of a 2-stroke marine diesel engine using on-board measurements

The use of biofuels in the marine industry is attracting interest as a potential mid-term solution towards its decarbonization targets. To study the biofuels effect on engine performance, combustion mechanism and emissions an extended experimental investigation was conducted on a commercial vessel's electronically controlled slow-speed 2-stroke engine. The fuels used were a biofuel blend, B30, comprising 70% Very Low Sulfur Fuel Oil and 30% second generation biofuel, gas oil (MGO) and crude oil (HFO). The measurements were conducted according to the International Maritime Organization guidelines. Cylinder pressure measurements were performed and analyzed to derive power, fuel consumption and combustion rate and engine settings. This allowed to isolate the biofuel's effect on performance and emissions. B30 effect on performance and combustion was found minimal without effect on the injection system. Fuel efficiency was minorly impacted. NOx emissions were increased by 7% compared to MGO and 3.5% compared to HFO, remaining compliant to legislation. Use of B30 had minimal effect on CO2 emissions, thus actual benefit lies on the well-to-tank path. It is concluded that the 30% biofuel blend can be used on electronically controlled 2-stroke engines with minimal impact on engine performance, fuel consumption and only small increase of NOx emissions.

Characterization of the physical and weathering properties of low sulfur fuel oil (LSFO) and its spreading on water surface

Effective countermeasures against the marine pollution caused by spilled oil are enabled based on the understanding of its physical and weathering characteristics. In that sense, our knowledge of the newly enforced low-sulfur fuel oil (LSFO) needs to be secured urgently. First, we show that the oil viscosity increases with decreasing temperature, following the William-Landel-Ferry law developed for bunker oil. The meso-stable emulsion is achieved from the emulsion test, of which the viscosity is 10–100 times larger than the normal one. On the other hand, the portion of the evaporation of LSFO was insignificant (less than 3%), and thus, its effect on the oil properties is not substantial except the increase of the viscosity. In addition, we experimentally examine the spreading features (e.g., spreading area and rate) of LSFO on the water surface in the circulating water bath. We find that initially, the oil spreading area increases quite fast but saturates, of which the details are explained in terms of the driving and retarding forces involved in the spreading processes. Finally, considering the procured properties of the LSFO, we performed a numerical simulation of spreading LSFO on the water surface with a scale of hundred meters, which shows that our analysis can be extended to larger scales.

Article: Green Shipping and Trade: Allocating Costs of the IMO Sulphur Regulation 2020

In January 2020 the Internatoinal Maritime Organisation (IMO) imposed, down from 3.5% m/m, a new limit of 0.50% m/m Sulphur limit from exhaust gases originating from commercial vessels. This new standard forced the maritime industry to switch to compliant fuels (such as Very Low Sulphur Fuel Oil (VLSFO) and ultra-low sulphur fuel oil (ULSFO) blends) or use an exhaust gas cleaning system (EGCS). Although there may be a consensus that this is a good thing, achievement of benefits has created contractual challenges for the industry. Responsibilities are divided between shipowner and charterer through forming a voyage charter, a time charter, or a bareboat charter (BBC). Baltic and International Maritime Council (BIMCO) and Intertanko provide standard contracts allocating the responsibilities of compliance with IMO Sulphur regulations between shipowner and charterer under the time charter. The compliance obligations under the voyage charterparty and BBC are still unaddressed. Here, we address them and offer an allocation of the responsibility. Charterparty, VLSFO, EGCS, contract, obligation, fixtures, Sulphur

Optimization of Liner Operations and Fuel Selection considering Emission Control Areas.

The continuous expansion of shipping trade has brought about increasingly serious marine pollution problems. In the context of emission reduction in the global shipping industry, this paper focuses on the operation optimization of container ships inside and outside the emission control area (ECA). From the dual perspectives of shipowners and the general public, models in the annual operating cycle are established to study the economic and environmental benefit differences between traditional fuels, i.e., heavy fuel oil (HFO) and low-sulfur fuel oil (LSFO), and alternative fuels, i.e., liquefied natural gas (LNG) and methanol. Sensitivity analysis was carried out for the proportion of ECA and ship speed. The results show that, in the current situation of high natural gas prices, the use of HFO after the installation of scrubbers is still the most cost-effective option in the short term, followed by the use of LSFO and methanol. LNG is no longer an attractive option, while LSFO and methanol are the best options for both cost and the environment. With the tightening of ECA regulations, methanol will become the optimal choice when the ECA ratio is higher than 47%. By reducing the speed of the ship, the pollutant emission can be effectively reduced, but it will also lead to an overall decrease in profits. Considering the future "zero carbon" emission targets, slow streaming is only suitable as a short-term response measure, while switching to green power energy is a choice that is more in line with the long-term development strategy.

Operational concerns from compliance of IMO2020 sulphur limit through VLSFO

From Jan 01, 2020, International Maritime Organisation (IMO) reduced the permissible sulphur content from bunker fuel used on ships from 3.5 % m/m in 2012 to 0.50 % m/m. The maritime industry is consequently abandoning High Sulphur Fuel Oil (HSFO) and employing Very Low Sulphur Fuel Oil (VLSFO) blends or using the Exhaust Gas Cleaning System (EGCS) that allows the combustion of HSFO by removing access sulphur from the exhaust gas of a ship. However, these compliance mechanisms present their own Technical and operational challenges. The concern that the specifications of VLSFO are hidden is groundless, as they must comply with ISO 8217. Thus, the problems with VLSFO blends are not their specs but the difficulty attached to their handling and use. Major problems with VLSFO blends are the breakdown of the main engine, poor liner conditions, collapsed piston rings, and consequential scuffing caused by mismanagement of cylinder oil and feed rate, improper maintenance of Piston Rings and Cylinder liner. Some other concerns with VLSFO blends are low shelf life, high sensitivity, admissibility of onboard testing, the readiness of seafarers, and other compliance difficulties. Training seafarers, technological awareness, and constant care can only achieve adequate compliance.

Process for Producing Light Olefins and Low-sulfur Fuel Oil Components

Process for Producing Light Olefins and Low-sulfur Fuel Oil Components

LNG 燃料 推進船의 燃料 品質基準에 關한 立法論적 硏究

The shipping industry, which has been using fossil fuels for a long time, has been making various efforts under the auspices of the International Maritime Organization to reduce air pollutants from ships. From January 2020, all ships engaged on international voyages must use fuel oil with a sulfur content of less than 0.5%. In order to comply with this international regulation, ships are required to install an Exhaust Gas Cleaning System, use Low-Sulfur Fuel Oil, or switch to Liquefied Natural Gas Fuelled ships. Among them, LNG, an eco-friendly fuel oil, is attracting attention as a new ship fuel. LNG fuel can reduce not only sulfur oxides but also nitrogen oxides and greenhouse gas emissions, so it is evaluated as the most commercialized marine fuel that can satisfy the currently reinforced air environment regulations. In order to revitalize the supply market for eco-friendly LNG fuel, it is most important to build a bunkering infrastructure in consideration of ship navigation routes, but the quality of the supplied fuel is also an important factor. In this study, the current international standards for ship fuel oil quality management, International Maritime Conventions, and domestic legal regulations are reviewed. Consider whether these regulations are appropriate to properly manage quality and prevent marine pollution caused by the use of LNG fuels of inappropriate quality in consideration of the characteristics of LNG fuels represented by aging effect. Through this, it recognizes the importance of LNG fuel quality management and proposes a legislative improvement proposal for LNG fuel quality management including LNG fuel delivery note containing information on methane number and fuel sample management, and providing material safety data sheet.

Choice of Emission Control Technology in Port Areas with Customers’ Low-Carbon Preference

The choice of emission control technology in a port supply chain under a cap-and-trade scheme considering low-carbon preferences of customers, is explored in this study. In port areas, the port supply chain consisting of one port and one ship can adopt either shore power (SP) or low sulfur fuel oil (LSFO) to reduce emissions. The economic and social performance of the port supply chain when either SP or LSFO is implemented is compared under three different game models (port-leader Stackelberg game, ship-leader Stackelberg game and the Nash game). The obtained results show that the profits and emissions in the Nash game are higher than those in the other two games. When environmental concern is relatively small, social welfare in the Nash game is the highest, while social welfare in the one-party-dominant structure is superior to that in the Nash structure, under high environmental concern. When the customers’ low-carbon preferences and carbon prices are low, both the supply chain’s profits and carbon emissions when LSFO is used are higher than those from using SP. From the perspective of social welfare maximization, in general, LSFO is preferred when carbon price, customers’ low-carbon preference and environmental concern are all low or are all high. Otherwise, SP is the optimal decision. The findings can provide insights for governments in formulating emission control policies according to their own interests.

Analysis of Characteristic Changes of Blended Very Low Sulfur Fuel Oil on Ultrasonic Frequency for Marine Fuel

The demand for very low sulfur fuel oil (VLSFO) with a sulfur content of less than 0.5% has increased since the IMO2020 regulations were published. However, most VLSFOs for marine fuel are produced by blending two fuel oils with different sulfur contents, which causes some problems, such as sludge formation. This study investigates the effect of ultrasonic irradiation frequency (25 and 72 kHz), ultrasonic irradiation time (0, 12, and 24 h), and the blending ratio (marine gas oil (MGO) and bunker-A (B-A) with weight ratios of 25:75, 50:50, and 75:25 on the characteristics of blended VLSFO. After 12 h of irradiation time and a frequency of 25 kHz, the amount of carbon residue decreases with increasing MGO content; it decreases by 33% for 75% MGO. However, at 72 kHz, the carbon residue increases with increasing MGO content, implying that the change in carbon residue depends on the ultrasonic frequency. After 24 h, the carbon residue does not decrease in any scenario; however, it does increase in some cases due to asphaltene reaggregation caused by excessive ultrasonic irritation. The sulfur content decreases by approximately 4% for the 100% B-A condition.