Search Results (14)

Cryogenic Carbon Capture (CCC) has emerged as a promising technology to enhance the sustainability of Liquefied Natural Gas (LNG) operations in line with the International Maritime Organization’s (IMO) decarbonization targets. This study investigates the integration of CCC within Floating Storage and Regasification Units (FSRUs), leveraging LNG’s cryogenic potential to improve CO₂ capture efficiency and optimize energy use. A detailed structural analysis of the FSRU’s energy balance was conducted considering variable regasification performance in open- and closed-loop regimes, followed by a Thermoflow-based simulation to assess the impact of CCC integration under real operational conditions. The results demonstrate that incorporating CCC into the FSRU’s closed-loop regasification process enables effective CO₂ capture and separation from the flue gas emitted by the Wärtsilä 8L50DF and 6L50DF dual-fuel electric diesel generators, as well as the boiler system. The study identifies a potential fuel consumption optimisation of 22% and a CO₂ capture rate of 100%, where the energy balance process requires 17.4 MW of combined energy unitisation. In addition, the study highlights the role of LNG cold energy potential in optimising heat exchange and mitigating thermal losses. These findings support the feasibility of CCC as a viable decarbonisation strategy for LNG FSRU operations. Future research should focus on improving system scalability and evaluating long-term performance under varying environmental and operational conditions. Full article

The increasing emphasis on environmental sustainability and stricter gas emissions regulations has made the optimization of fuel and emissions a crucial factor for marine propulsion systems. This paper investigates the potential to improve fuel efficiency and reduce emissions of LNG ship propulsion systems by using different load sharing strategies in Dual-Fuel Diesel-Electric (DFDE) propulsion systems. Using data collected from on-board cyclic measurements and an optimization model, the effects of different load sharing strategies for various types of fuel, such as HFO, MDO, and LNG, under different engine load conditions were investigated. The results of these strategies are compared with those of on-board power management systems (PMS), which evenly allocate power among the engines, irrespective of fuel usage and emission levels. The results show that load adjustments according to the optimization model can considerably increase fuel economy and contribute to the reduction of CO₂ and NO_x compared to standard practice at the equal load in different ship operating modes. Our approach introduces an innovative optimization concept that has been proven to improve fuel efficiency and reduce emissions beyond standard practices. This paper demonstrates the robustness of the model in balancing environmental and operational objectives and presents an effective approach for more sustainable and efficient ship operations. The results are in line with global sustainability efforts and provide valuable insights for future innovations in energy optimization and ship emission control. Full article

Due to growing environmental concerns and stringent emissions regulations, optimizing the fuel consumption of marine propulsion systems is crucial. This work deals with the potential in an LNG ship propulsion system to reduce fuel consumption through controlled load distribution between engines in Dual-Fuel Diesel Electric (DFDE) plant. Based on cyclical data acquisition measured onboard and using an optimization model, this study evaluates different load distribution strategies between setups according to the optimization model results and automatic (equal) operation to determine their effectiveness in improving fuel efficiency. The analysis includes scenarios with different fuel types, including LNG, MDO and HFO, at different engine loads. The results indicate that load distribution adjustment based on the optimization model results significantly improves fuel efficiency compared to conventional methods of uniform load distribution controlled by power management systems in almost all load intervals. This research contributes to the maritime industry by demonstrating that strategic load management can achieve significant fuel savings and reduce environmental impact, which is in line with global sustainability goals. This work not only provides a framework for the implementation of more efficient energy management systems on LNG vessels, but also sets a benchmark for future innovations in maritime energy optimization as well as in the view of exhaust emission reduction. Full article

The research provides a comparative theoretical investigation of the operational characteristics of an electric semi-truck and vehicles powered by conventional combustion engines using diesel fuel, hydrotreated vegetable oil (HVO), and methane (including biomethane) in the dual fuel configuration. The Volvo tractor units that are offered for retail in 2024, namely the Volvo FH Electric, Volvo FH500 in dual fuel configuration, and Volvo FH500TC Diesel Euro VI, were chosen for comparison. The considerations encompassed include the road tractor’s mass, energy usage, power-to-weight ratio, dynamics, ability to recharge or refuel, payload restrictions, impact on logistics expenses, compliance with regulations on drivers’ working hours, and a report on carbon dioxide emissions. The study concludes by discussing and drawing conclusions on the competitiveness of different drive types in truck tractors, specifically in relation to identifying the most suitable areas of application. Synthetic conclusions demonstrate the high effectiveness of the electric drive in urban and suburban conditions. However, vehicles equipped with internal combustion engines using renewable fuels fill the gap in energy-intensive drives in long-distance transport. Full article

The International Maritime Organization (IMO) has set targets to reduce carbon emissions from shipping by 40% by 2030 (IMO2030) and 70% by 2040 (IMO2050). Within the framework of decarbonising the shipping industry, liquefied natural gas (LNG) fuel and carbon capture technologies are envisioned as a transitional option toward a pathway for clean energy fuels. The aim of the complex experimental and computational studies performed was to evaluate the CO₂ capture potential through the utilisation of LNG cold potential on the FSR-type vessel within a dual-fuel propulsion system. Based on the experimental studies focused on actual FSRU-type vessel performance, the energy efficiency indicators of the heat exchanging machinery were determined to fluctuate at a 0.78–0.99 ratio. The data obtained were used to perform an algorithm-based systematic comparison of energy balances between LNG regasification and fuel combustion cycles on an FSRU-type vessel. In the due course of research, it was determined that LNG fuel combustion requires 18,254 kJ/kg energy to separate and capture CO₂ in the liquid phase to form exhaust gas; meanwhile, low sulfur marine diesel oil (LSMDO) requires 13,889 kJ/kg of energy. According to the performed calculations, the regasification of 1 kg LNG requires 1018 kJ/kg energy, achieving a cryogenic carbon capture ratio of 5–6% using LNG as a fuel and 7–8% using LSMDO as a fuel. The field of carbon capture in the maritime industry is currently in its pioneering stage, and the results achieved through research establish an informative foundation that is crucial for the constructive development and practical implementation of cryogenic carbon capture technology on dual-fuel ships. Full article

To meet stringent fuel sulfur limits, together with NO_x limits, ships are increasingly utilizing dual-fuel (DF) engines operating with liquified natural gas (LNG) as the primary fuel. Compared to diesel, LNG combustion produces less CO₂, which is needed in targeting the reduction of the shipping impact on the climate; however, this could be significantly interfered with by the methane emission formation. In this study, the methane emissions, together with other emission components, were studied by measurements onboard a state-of-the-art RoPax ferry equipped with two different development-stage engines. The results from the current standard state-of-the-art DF engine showed methane levels that were, in general, lower than what has been reported earlier from onboard studies with similar sized DF engines. Meanwhile, the methane emission from the DF engine piloting the new combustion concept was even lower, 50–70% less than that of the standard DF engine setup. Although the CO₂ was found to slightly increase with the new combustion concept, the CO₂ equivalent (including both methane and CO₂) was smaller than that from the standard DF engine, indicating that the recent development in engine technology is less harmful for the climate. Additionally, lower NO_x and formaldehyde levels were recorded from the new combustion concept engine, while an increase in particle emissions compared to the standard DF engine setup was observed. These need to be considered when evaluating the overall impacts on the climate and health effects. Full article

In order to convert the marine diesel engine into an LNG (Liquefied Natural Gas)–diesel dual-fuel engine and ensure its power and emission characteristics, a new calibration method is proposed, and the fuel substitution ratio, economy and detailed particulate matter emission law after the engine is calibrated using this method are studied. The calibration method takes the peak pressure in the cylinder and the exhaust temperature as constraints and uses the diesel mass substitution ratio as the objective function. Based on the proposed calibration method, the engine is calibrated by setting up a calibration test bench. The test obtains the distribution characteristics of the diesel mass substitution ratio under various operating conditions of the engine. The results show that the proposed calibration method allows the dual-fuel engine to achieve the same power performance as the original engine. At the same time, the diesel mass substitution ratio of the calibrated dual-fuel engine can reach up to 95% (800 r/min @ 800 Nm, 900 r/min @ 800 Nm and 1000 r/min @ 800 Nm). The substitution ratio in the range of 900 r/min~1200 r/min at a common speed is more than 70%, and the average diesel mass substitution ratio under all working conditions is 71%. Furthermore, the study of engine economy shows that the BSFC (brake specific fuel consumption) of the dual-fuel mode is higher than that of the pure diesel mode when working under external characteristics, propulsion characteristics and different loads at 1000 r/min speed. This is more obvious when the load is small, and the two are closer when the load is medium or high; however, the fuel cost when the engine works in dual-fuel mode is much lower than that of the pure diesel mode. In the usual speed and load range, the particulate matter emission test shows that its particle size distribution, total number of particles and particle volume are significantly reduced in the dual-fuel mode. Full article

Decarbonization of ship power plants and reduction of harmful emissions has become a priority in the technological development of maritime transport, including ships operating in seaports. Engines fueled by diesel without using secondary emission reduction technologies cannot meet MARPOL 73/78 Tier III regulations. The MEPC.203 (62) EEDI directive of the IMO also stipulates a standard for CO₂ emissions. This study presents the results of research on ecological parameters when a CAT 3516C diesel engine is replaced by a dual-fuel (diesel-liquefied natural gas) powered Wartsila 9L20DF engine on an existing seaport tugboat. CO₂, SO₂ and NO_x emission reductions were estimated using data from the actual engine load cycle, the fuel consumption of the KLASCO-3 tugboat, and engine-prototype experimental data. Emission analysis was performed to verify the efficiency of the dual-fuel engine in reducing CO₂, SO₂ and NO_x emissions of seaport tugboats. The study found that replacing a diesel engine with a dual-fuel-powered engine led to a reduction in annual emissions of 10% for CO₂, 91% for SO₂, and 65% for NO_x. Based on today’s fuel price market data an economic impact assessment was conducted based on the estimated annual fuel consumption of the existing KLASCO-3 seaport tugboat when a diesel-powered engine is replaced by a dual-fuel (diesel-natural gas)-powered engine. The study showed that a 33% fuel costs savings can be achieved each year. Based on the approved methodology, an ecological impact assessment was conducted for the entire fleet of tugboats operating in the Baltic Sea ports if the fuel type was changed from diesel to natural gas. The results of the assessment showed that replacing diesel fuel with natural gas achieved 78% environmental impact in terms of NO_x emissions according to MARPOL 73/78 Tier III regulations. The research concludes that new-generation engines on the market powered by environmentally friendly fuels such as LNG can modernise a large number of existing seaport tugboats, significantly reducing their emissions in ECA regions such as the Baltic Sea. Full article

Climate change and severe emission regulations in many countries demand fuel and engine researchers to explore sustainable fuels for internal combustion engines. Natural gas could be a source of sustainable fuels, which can be produced from renewable sources. This article presents a complete overview of the liquefied natural gas (LNG) as a potential fuel for diesel engines. An interesting finding from this review is that engine modification and proper utilization of LNG significantly improve system efficiency and reduce greenhouse gas (GHG) emissions, which is extremely helpful to sustainable development. Moreover, some major recent researches are also analyzed to find out drawbacks, advancement and future research potential of the technology. One of the major challenges of LNG is its higher flammability that causes different fatal hazards and when using in dual-fuel engine causes knock. Though researchers have been successful to find out some ways to overcome some challenges, further research is necessary to reduce the hazards and make the fuel more effective and environment-friendly when using as a fuel for a diesel engine. Full article

Current Greenhous gas emissions (GHG) from maritime transport represent around 3% of global anthropogenic GHG emissions and will have to be cut in half by 2050 to meet Paris agreement goals. Liquefied natural gas (LNG) is by many seen as a potential transition fuel for decarbonizing shipping. Its favorable hydrogen to carbon ratio compared to diesel (marine gas oil, MGO) or bunker fuel (heavy fuel oil, HFO) translates directly into lower carbon emissions per kilowatt produced. However, these gains may be nullified once one includes the higher Well-to-tank emissions (WTT) of the LNG supply chain and the vessel’s un-combusted methane slip (CH₄) from its combustion engine. Previous studies have tended to focus either on greenhouse gas emissions from LNG in a Well-to-wake (WTW) perspective, or on alternative engine technologies and their impact on the vessel’s Tank-to-wake emissions (TTW). This study investigates under what conditions LNG can serve as a transition fuel in the decarbonization of maritime transport, while ensuring the lowest possible additional global warming impact. Transition refers to the process of moving away from fossil fuels towards new and low carbon fuels and engine technologies. Our results show: First, the importance of applying appropriate engine technologies to maximize GHG reductions; Second, that applying best engine technologies is not economically profitable; Third, how regulations could be amended to reward best engine technologies. Importantly, while the GHG reduction of LNG even with best engine technology (dual fuel diesel engine) are limited, ships with these engines can with economically modest modification switch to ammonia produced with renewable energy when it becomes available in sufficient amounts. Full article

This paper presents the results of a numerical study on the parameters that affect the efficiency of the cogeneration cycle of a ship’s power plant. The efficiency was assessed based on the excess power (N_gen.) of a free turbine, operated with the inflow of gaseous nitrogen, which was used to generate electricity. A mathematical model and simulation of the regenerative cycle were created and adjusted to operate with a dual-fuel (diesel-liquid natural gas (LNG)) six-cylinder four-stroke engine, where the energy of the exhaust gas was converted into mechanical work of the regenerative cycle turbine. The most significant factors for N_gen. were identified by parametrical analysis of the cogeneration cycle: in the presence of an ‘external’ unlimited cold potential of the LNG, N_gen. determines an exhaust gas temperature Te_g of power plant; the pressure of the turbo unit and nitrogen flow are directly proportional to N_gen. When selecting the technological units for cycle realization, it is rational to use high flow and average ${\pi }_T$ pressure (~3.0–3.5 units) turbo unit with a high adiabatic efficiency turbine. The effect of the selected heat exchangers with an efficiency of 0.9–1.0 on N_gen. did not exceed 10%. With LNG for ‘internal’ use in a ship as a fuel, the lowest possible temperature of N₂ is necessary, because each 10 K increment in N₂ entering the compressor decreases N_gen. by 5–8 kW, i.e., 5–6%. Full article

Dual fuel engines using diesel and fuels that are gaseous at normal conditions are receiving increasing attention. They permit to achieve the same (or better) than diesel power density and efficiency, steady-state, and substantially similar transient performances. They also permit to deliver better than diesel engine-out emissions for CO₂, as well as particulate matter, unburned hydrocarbons, and nitrous oxides. The adoption of injection in the liquid phase permits to further improve the power density as well as the fuel conversion efficiency. Here, a model is developed to study a high-pressure, 1600 bar, liquid phase injector for liquefied natural gas (LNG) in a high compression ratio, high boost engine. The engine features two direct injectors per cylinder, one for the diesel and one for the LNG. The engine also uses mechanically assisted turbocharging (super-turbocharging) to improve the steady-state and transient performances of the engine, decoupling the power supply at the turbine from the power demand at the compressor. Results of steady-state simulations show the ability of the engine to deliver top fuel conversion efficiency, above 48%, and high efficiencies, above 40% over the most part of the engine load and speed range. The novelty of this work is the opportunity to use very high pressure (1600 bar) LNG injection in a dual fuel diesel-LNG engine. It is shown that this high pressure permits to increase the flow rate per unit area; thus, permitting smaller and lighter injectors, of faster actuation, for enhanced injector-shaping capabilities. Without fully exploring the many opportunities to shape the heat release rate curve, simulations suggest two-point improvements in fuel conversion efficiency by increasing the injection pressure. Full article

Diesel-LNG internal combustion engines (ICEs) are the most promising light and heavy-duty truck (HDT) powering solution for a transition towards a mixed electric-hydrogen renewable energy economy. The diesel-liquid CH₄ ICEs have indeed many commonalities with diesel-liquid H₂ ICEs, in the infrastructure, on-board fuel storage, and injection technology, despite the fact H₂ needs a much lower temperature. The paper outlines the advantages of dual fuel (2F) diesel-LNG ICEs developed adopting two high-pressure (HP) injectors per cylinder, one for the diesel and one for the LNG, plus super-turbocharging. The diesel-LNG ICEs provide high fuel energy conversion efficiencies, and reduced CO₂, PM, and NOx emissions. Super-turbocharging permits the shaping of the torque curve while improving acceleration transients. Diesel-LNG ICEs may also clean up the air of background pollution in many polluted areas in the world. Computational results prove the steady-state advantages of the proposed novel design. While the baseline diesel model is a validated model, the 2F LNG model is not. The perfect alignment of the diesel and diesel-LNG ICE performances proven by Westport makes however the proposed results trustworthy. Full article

Data from a two-stage axial vapor cryogenic compressor on the dual-fuel diesel–electric (DFDE) liquefied natural gas (LNG) carrier were measured and analyzed to investigate compressor energy and exergy efficiency in real exploitation conditions. The running parameters of the two-stage compressor were collected while changing the main propeller shafts rpm. As the compressor supply of vaporized gas to the main engines increases, so does the load and rpm in propulsion electric motors, and vice versa. The results show that when the main engine load varied from 46 to 56 rpm at main propulsion shafts increased mass flow rate of vaporized LNG at a two-stage compressor has an influence on compressor performance. Compressor average energy efficiency is around 50%, while the exergy efficiency of the compressor is significantly lower in all measured ranges and on average is around 34%. The change in the ambient temperature from 0 to 50 °C also influences the compressor’s exergy efficiency. Higher exergy efficiency is achieved at lower ambient temperatures. As temperature increases, overall compressor exergy efficiency decreases by about 7% on average over the whole analyzed range. The proposed new concept of energy-saving and increasing the compressor efficiency based on pre-cooling of the compressor second stage is also analyzed. The temperature at the second stage was varied in the range from 0 to −50 °C, which results in power savings up to 26 kW for optimal running regimes. Full article