Search Results (45)

This study investigated the production of biodiesel from canola oil, the formulation of sustainable ternary fuel blends with diesel and alcohol (ethanol or propanol), and the experimental and machine learning-based modeling of their physical properties, including density and viscosity over a temperature range of 10 °C to 40 °C. Biodiesel was synthesized via alkali-catalyzed transesterification (6:1 methanol-to-oil molar ratio, 0.5 wt % NaOH of oil) and blended with diesel and alcohols (ethanol and propanol) in varying volume ratios. The experimental results revealed that blend density decreased from 0.8622 g/cm³ at 10 °C to 0.8522 g/cm³ at 40 °C for a blend containing ethanol. Similarly, the viscosity showed a significant reduction with temperature, e.g., the blend exhibited a viscosity decline from 8.5 mPa·s at 10 °C to 7.2 mPa·s at 40 °C. Increasing the alcohol or diesel content further reduced density and viscosity due to the lower intrinsic properties of these components. The machine learning models, Gaussian process regression (GPR), support vector regression (SVR), artificial neural networks (ANN), and decision tree regression (DTR), were applied to predict the properties of these blends. GPR demonstrated the best predictive performance for both density and viscosity. These findings confirm the strong potential of GPR for the accurate and reliable prediction of fuel blend properties, supporting the formulation of alternative fuels optimized for diesel engine performance. These aspects contribute new insights into modelling strategies for sustainable fuel formulations. Full article

Dimethyl carbonate (DMC) and polyoxymethylene dimethyl ethers (PODE also known as OME) are possible diesel additives that can be produced sustainably using green methanol. DMC can be produced from CO₂ and methanol, while PODE can be produced from methanol and formaldehyde. In this study both DMC and PODE were investigated as drop-in diesel fuel additives regarding material compatibility, injection behavior, as well as particle and exhaust emissions. Both DMC and PODE are known to be incompatible with certain materials used as seals in the fuel injection system. Therefore, the material compatibility of both neat DMC and PODE as well as blends with B0 was investigated, with both PFTE and FFKM showing good compatibility. The hydraulic injection behavior of DMC–diesel and PODE–diesel blends was investigated experimentally, showing the need for compensating injection quantities for DMC and PODE blends to match neat diesel power output due to their lower calorific values. Energetic compensation can be achieved by higher injection pressures or longer injection durations. Engine tests have been conducted with both DMC–diesel and PODE–diesel blends, demonstrating the potential to mitigate the particle–NO_X trade-off. Full article

This study conducts a detailed analysis of the mixed combustion of dissociated methanol gas (DMG) and methanol in a marine medium-speed methanol engine through numerical simulation methods. The research focuses on the impact of partially replacing methanol with DMG on engine combustion characteristics and emissions under both stoichiometric and lean-burn conditions. Employing the MAN L23/30H diesel engine as the experimental model, direct injection of DMG is achieved by installing gas injectors on the cylinder head. Utilizing the CONVERGE software, we simulate the injection and combustion processes of methanol and DMG and subsequently analyze the effects of varying DMG blending ratios on in-cylinder pressure, heat release rate, mean chamber temperature, as well as NOx, HC, CO, and soot emissions. The research findings indicate that, under stoichiometric combustion conditions at both rated and idle speeds, the incorporation of DMG leads to increases in the peak in-cylinder pressure, peak heat release rate, and peak in-cylinder temperature, with these peaks occurring earlier. Additionally, it is observed that emissions of HC, CO, and soot are reduced. Under lean combustion conditions at rated speed, in the absence of DMG blending, increasing the excess air ratio results in an initial increase followed by a decrease in both fuel-indicated and overall-indicated thermal efficiency. However, with the blending of DMG, these efficiencies improve as the excess air ratio increases. Notably, the highest efficiencies are achieved when the excess air ratio is 1.8 and the blending ratio of DMG is 30%. Full article

Diesel engines are extensively employed in transportation, agriculture, and industry due to their high thermal efficiency and fuel economy. However, the combustion of conventional diesel fuel is accompanied by substantial emissions of pollutants, including carbon monoxide (CO), hydrocarbons (HC), nitrogen oxides (NO_x), and carbon dioxide (CO₂), posing significant threats to environmental quality. Biodiesel, as a renewable and cleaner alternative fuel, can significantly reduce emissions of CO, HC, and particulate matter (PM) due to its unique molecular structure. Nonetheless, its lower calorific value and poor cold-start performance limit its application, while its high oxygen content may contribute to increased NO_x emissions. To address these limitations, researchers have proposed blending biodiesel with alcohol-based fuels such as methanol, ethanol, or butanol to create synergistic combustion systems that optimize engine performance and emission characteristics. This paper systematically reviews the effects of alcohol fuels on the performance and emission characteristics of biodiesel blends in diesel engines. Studies indicate that the addition of alcohol fuels can significantly enhance engine performance by improving fuel atomization, extending ignition delay, and increasing premixed combustion efficiency. These enhancements result in higher cylinder pressure, net heat release rate (HRR), and brake thermal efficiency (BTE), while reducing brake-specific fuel consumption (BSFC) to some extent. Moreover, most studies report that alcohol fuels help reduce CO, HC, smoke, and NO_x emissions but tend to increase CO₂ emissions. However, some findings suggest that in certain cases, the opposite results may occur. The impact of different types of alcohol fuels on performance and emissions varies significantly, requiring a comprehensive evaluation of their properties, such as latent heat, viscosity, and oxygen content. Although the appropriate addition of alcohol fuels demonstrates substantial potential for optimizing engine performance and reducing emissions, excessive blending may lead to adverse effects, necessitating careful control of the blending ratio. Future research should consider mixing two or more alcohol fuels with biodiesel to explore synergistic effects beyond the capabilities of single alcohols. Additionally, further studies should focus on optimizing fuel compositions and emission control strategies for varying operating conditions. Full article

In the era of decarbonization driven by environmental concerns and stimulated by legislative measures such as Fit for 55, the industry and transportation sectors are increasingly replacing petroleum-based fuels with those derived from renewable sources. For many years, the share of these fuels in blends used to power compression ignition engines has been growing. The primary advantage of this fuel technology is the reduction of GHG emissions while maintaining comparable engine performance. However, these fuel blends also have drawbacks, including limited ability to form stable mixtures or the requirement for chemical stabilizers. The stability of these mixtures varies depending on the type of alcohol used, which limits the applicability of such fuels. This study focuses on evaluating the impact of eight types of alcohol fuels, including short-chain (methanol, ethanol, propanol) and long-chain alcohols (butanol, pentanol, hexanol, heptanol, and octanol), on the most critical operational parameters of an industrial engine and exhaust emissions. The engines being compared operated at a constant speed and under a constant load, either maximum or close to maximum. The study also evaluated the effect of alcohol content in the mixture on combustion process parameters such as peak cylinder pressure and heat release, which are the basis for parameterizing the engine’s combustion process. Determining ignition delay and combustion duration is fundamental for optimizing the engine’s thermal cycle. As the research results show, both the type of alcohol and its concentration in the mixture influence these parameters. Another parameter important from a usability perspective is engine stability, which was also considered. Engine performance evaluation also includes assessing emissions, particularly the impact of alcohol content on NO_x and soot emissions. Based on the analysis, it can be concluded that adding alcohol fuel to diesel in a CI engine increases ignition delay (up to 57%), p_max (by approximately 15–20%), HRR_max (by approximately 80%), and PPR_max (by approximately 70%). Most studies indicate a reduction in combustion duration with increasing alcohol content (by up to 50%). For simple alcohols, an increase in thermal efficiency (by approximately 15%) was observed, whereas for complex alcohols, a decrease (by approximately 10%) was noted. The addition of alcohol to diesel slightly worsens the stability of the CI engine. Most studies pointed to the positive impact of adding alcohol fuel to diesel on NOx emissions from the compression ignition engine, with the most significant reductions reaching approximately 50%. Increasing the alcohol fuel content in the diesel blend significantly reduced soot emissions from the CI engine (by up to approximately 90%). Full article

The conventional utilization of fossil fuels precipitates uncontrolled carbon dioxide and sulfur oxides emissions, thereby engendering pronounced atmospheric pollution and global health ramifications. Within the maritime domain, concerted global initiatives aspire to mitigate emissions by 2050, centering on the adaptation of engines, alteration of fuel compositions, and amelioration of exhaust gas treatment protocols. This investigation pioneers experimentation with marine gas oil augmented by methanol, a practice conventionally encumbered by prohibitively expensive additives. Successful amalgamation of methanol, animal-derived biodiesel, and marine gas oil (MGO) is empirically demonstrated under meticulously controlled thermal conditions, creating a homogeneous blend with virtually zero sulfur content and reduced carbon content, featuring characteristics akin to conventional marine gas oil but with no use of expensive emulsifiers. This new blend is suitable for employment in maritime engines utilizing Delaval technology, yet with significantly lower energy requirements compared to those necessitated using conventional very low sulfur fuel oil (VLSFO) with a maximum sulfur content of 0.5% w/w. Full article

Approximately 25% of global carbon emissions come from food production. Renewable fuels are crucial for curbing greenhouse gas (GHG) emissions from vehicles, non-road machines, and agricultural machinery. Tractors, key to modern farming, are central to these efforts. As agriculture strives for sustainability, alternative fuels like methanol and hydrotreated vegetable oil (HVO) are arousing interest because they are renewable and offer potential for blending for use in diesel engines. Methanol and HVO have limited solubility in direct mixing, so the addition of a co-solvent is essential. This study addresses the research gap regarding the properties of HVO and methanol blends with co-solvents. It investigated the impact of three co-solvents, 1-dodecanol, 1-octanol, and methyl butyrate, on the miscibility of HVO and methanol. The experimental measurements cross-varied the co-solvent type with different blending ratios (MeOH5 and MeOH10). Investigated parameters include fuel density, kinematic viscosity, distillation properties, and surface tension. The co-solvents enabled the formation of a singular, clear, and homogeneous phase in methanol-HVO blends. The co-solvent 1-dodecanol demonstrated the highest solubilizing capacity for MeOH5 and MeOH10 blends, followed by 1-octanol. Adding co-solvents led to increased fuel density, decreased kinematic viscosity, and small changes in surface tension. These findings contribute to the optimization of methanol–HVO fuel blends for efficient and environmentally friendly use in vehicles, non-road machinery, and agricultural machinery. Full article

The impact of fossil fuel utilisation in different combustion systems on climate change due to greenhouse gas accumulation in the atmosphere is rather evident. A part of these gases comes from the large engines used for propulsion in marine applications. In the continuous global effort made by engine manufacturers to mitigate this negative impact, one way is represented by the utilisation of alternative fuels such as biodiesel and methanol, based on dedicated research to fulfil the more stringent regulations concerning pollutant emissions issued by piston heat engines. In this study, a numerical investigation was conducted on a four-stroke large marine diesel engine (ALCO 16V 251C) at several engine speeds and full load conditions. Different blends of diesel–methanol and biodiesel B20–methanol with methanol mass fractions of 10% and 20% were considered for theoretical analysis in two techniques of methanol supply: direct injection mode of a blend of base fuel diesel/biodiesel B20 with methanol and injection of methanol after the intercooler, and direct injection of the base fuel. The results show that, if 10% in power loss can be acceptable, then for diesel–methanol 10%, in the direct injection technology, the NOx emission can be reduced up to 19%, but with a compromise of an 8% increase in SOOT emission, while for biodiesel B20–methanol 10%, with the same direct injection method, the NOx emissions increase by up to 58% with the benefit of reducing SOOT by up to 23% relative to the original diesel fuel operation. For a 20% methanol fraction in blend fuel, the drop in power is more than 10% regardless of the method of methanol supply and the base fuel, diesel, or B20 used. Full article

Environmental pollution caused by marine engines fueled with fossil fuels is a matter of growing significance. The search for renewable and clean energy sources and improvements in the way fossil fuels are burnt aims to reduce the environmental impact of these engines. For this purpose, fatty acid methyl esters were produced from pure canola oil using KOH-assisted methanol-based transesterification with a maximum yield of 90.68 ± 1.6%. The marine engine’s model was created with CONVERGE software, followed by experimental verification. This paper examines the blended fuel characteristics of a diesel engine with biodiesel blends (0%, 5%, 10%, and 15%) at different loads of engines (50%, 75%, and 100%). It also explores the variation in these characteristics of B10 (10% biodiesel–diesel blends) at three different load conditions and four different EGR rates (0%, 5%, 10%, and 15%). The results indicate that the addition of biodiesel to diesel fuel reduces CO, HC, and soot emissions, while increasing NO_x emissions. Additionally, the EGR rate decreases NO_x emissions but results in higher levels of soot, CO, and HC emissions. Finally, response surface methodology was used to elicit the engine’s characteristics. It was determined that the optimum experimental operating conditions were 100% engine load, 6.9% biodiesel addition, and 7.7% EGR. The corresponding BTE, BSFC, NO_x, and HC emissions were 38.15%, 282.62 g/(kW-h), 274.38 ppm, and 410.37 ppm, respectively. Full article

The biodiesel industry is a promising field globally, and is expanding significantly and quickly. To create a biodiesel business that is both sustainable and commercially feasible, a number of studies have been conducted on the use of non-edible oils to produce biodiesel. Thus, this study highlights biodiesel synthesis from non-edible plant oils such as pongamia and jatropha using a glycerol separation technique with an AC high voltage method through the transesterification reaction. In this context, non-edible plant oil has emerged as an alternative with a high potential for making the biodiesel process sustainable. Moreover, the study introduces how the created biodiesel fuel behaves when burned in a diesel engine. The results showed that the optimum conditions for creating biodiesel were a temperature of 60 °C, a potassium hydroxide catalyst percentage by weight of oils of 1%, and a stirring time of 60 min at a 5:1 (v/v) ratio of methanol to oil. A high-voltage procedure was used to separate glycerol and biodiesel using two electrodes of copper with different distances between them and different high voltages. The results showed that, for a batch of 15 L, the minimum separating time was 10 min when the distance between the copper electrodes was 2.5 cm, and the high voltage was 15 kV. The density, kinematic viscosity, and flash point of jatropha oil were reduced from 0.920 to 0.881 g/cm³ at 15 °C, from 37.1 to 4.38 cSt at 40 °C, and from 211 to 162 °C, respectively, for the production of biodiesel. Additionally, the density, kinematic viscosity, and flash point of pongamia oil were reduced from 0.924 to 0.888 g/cm³ at 15 °C, from 27.8 to 5.23 cSt at 40 °C, and from 222 to 158 °C, respectively, for the production of biodiesel. The calorific value of jatropha oil was increased from 38.08 to 39.65 MJ/kg for the production of biodiesel, while that of pongamia oil was increased from 36.61 to 36.94 MJ/kg. The cetane number increased from 21 for oil to 50 for biodiesel and from 32 for oil to 52 for jatropha and pongamia biodiesel, respectively. In order to run an air-cooled, single-cylinder, four-stroke diesel engine at full load, the produced biodiesel fuel was blended with diesel fuel at different percentages—10, 20, and 30%—for jatropha and pongamia methyl esters. The produced engine power values were 3.91, 3.69, and 3.29 kW for B10, B20, and B30, respectively, compared with the engine power value of jatropha methyl ester, which was 4.12 kW for diesel fuel (B00); meanwhile, the values were 3.70, 3.36, and 3.07 kW for B10, B20 and B30, respectively, for pongamia methyl ester. The findings suggest that the biodiesel derived from non-edible oils, such as pongamia and jatropha, could be a good alternative to diesel fuel. Full article

As a clean alternative fuel oil for marine engines, methanol has received increasing attention, but its low cetane number requires diesel ignition, which increases the difficulty of retrofitting existing engine fuel injection systems. Polymethoxy dimethyl ether (PODE_n) is an ether fuel mixture whose chemical structural formula can be expressed as CH₃O(CH₂O)_nCH₃ ($n\ge 2$). PODE₃ is the predominant component in the blend, and its properties are representative of the blend. PODE is a low-carbon fuel with a high cetane number and is easy to compression ignite, and, as such, can be used to ignite methanol in a marine diesel engine. This article explores the combustion mechanism of mixed methanol–PODE fuel using the characteristics of PODE that can be easily mixed with methanol for combustion. Taking methanol and PODE₃ as representative fuels, the detailed combustion mechanism of PODE₃ and the detailed combustion mechanism of methanol are simplified using a DRGEPSA (direct relationship graph with error propagation (DRGEP) and sensitivity analysis (SA)) method. Based on the target engine cylinder combustion environment, a simplified mechanism for mixed methanol–PODE fuel is obtained, and the new mechanism is validated in terms of the ignition delay period and laminar flame speed. The results indicate that the newly constructed simplified mechanism is basically consistent with the ignition delay data and flame propagation speed data measured by a rapid compression machine (RCM), laying the foundation for the application of alternative methanol fuels in marine engines. Full article

The growth of the global shipping industry has increased the interest in the environmental impact of this sector. The International Maritime Organization adopted the initial Greenhouse Gas strategy for reducing GHG emissions from ships at the 72nd Marine Environment Protection Committee in April 2018. In this study, we carried out a life cycle assessment of nine production pathways of alternative fuels, including LNG, ammonia, methanol, and biofuels, and conducted an economic analysis considering the life cycle carbon pricing of each fuel pathway. Our results indicate that biomass-based FT-diesel, e-methanol, and e-ammonia are the most environmentally friendly, with GHG reductions of 92%, 88.2%, and 86.6%, respectively. However, our net present value analysis of ship life cycle cost considering carbon price indicated that using those fuels would not be cost-effective during the target period of study. Sensitivity analysis was performed by changing the life cycle carbon pricing from the baseline scenario, and we investigated the approximate years for when these alternative fuels will become more cost-effective compared to conventional fossil fuels. Further, to provide practical implications for shipping stakeholders, we analysed the effect of blending the same kinds of fuels with different production pathways. Full article

Sustainable ammonia is one of the leading candidates in the search for alternative clean fuels for marine applications. This paper aims to build a simulation model of a six-cylinder, four-stroke diesel engine to investigate the effects of increasing the ammonia proportion in methanol–ammonia fuel blends on engine performance and emissions. In the present study, the conditions of different speeds and different proportions of ammonia in fuel blends are investigated. The results show that the average effective pressure, brake power, and brake torque increase by about 5% with an increased ammonia substitution ratio. In terms of economic performance, the changes under medium and low speed conditions are not obvious. However, the change in high speed conditions is significant. The brake specific fuel consumption (BSFC) is reduced by 6.6%, and the brake thermal efficiency (BTE) is increased by 4%. It is found that the performance of the engine is best at medium speed. The best performance is achieved with higher efficiency and lower emissions. The present results can provide guidance for the optimization of ammonia–methanol blends and their applications in engines. Full article

Hydrogen is the most promising alternative fuel in the field of engines. Exhaust heat-assisted methanol dissociation is an attractive approach for generating hydrogen. In this work, simulations are conducted on a compression ignition engine fueled with different proportions of diesel-dissociated methanol gas (DMG) blends at intermediate engine speed, full load, and 0% EGR ratio. The results reveal that the indicated thermal efficiency and indicated mean effective pressure are greatly enhanced, combustion efficiency is increased, and regular emissions of CO, HC, and soot are reduced, while NOx emissions are reduced with increased DMG substitution. In addition, a simulation is conducted at an intermediate engine speed, full load, 15% DMG substitution ratio, and varying EGR ratios of 0–20%. The results indicate that the dual-fuel engine outperforms the original engine with respect to power, fuel economy, and regular emissions, once an optimal EGR rate is adopted. Full article

The environmentally sustainable production of biodiesel is important for providing both a renewable alternative transportation fuel as well as a fuel for power generation using diesel engines. This research evaluates the use of inexpensive catalysts derived from waste materials for converting triglycerides in seed oils into biodiesel composed of fatty acid methyl esters. The performance of CaO catalysts derived from the shells of oysters, mussels, lobsters, and chicken eggs was investigated. The shell-derived powders were calcined with and without the addition of zinc nitrate at 700–1000 °C for 4 h to yield CaO whereas the CaO-ZnO mixed catalyst were prepared by wet impregnation followed by calcination at 700 °C. The catalysts were characterized by XRF, XRD, TGA, SEM, FTIR and GC-MS. The CaO-ZnO catalysts showed slightly better conversion efficiency compared to CaO catalysts for the transesterification of canola oil. The mixed CaO-ZnO catalysts derived mainly from oyster shells showed the highest catalytic activity with >90% biodiesel yield at a 9:1 methanol-to-oil mole ratio within 10 min of ultrasonication. The reduction of toxicant emission from the generator is 43% and 60% for SO₂, 11% and 26% for CO, were observed for the biodiesel blending levels of B20 and B40, respectively. Full article