Search Results (226)

Road transport in the European Union is responsible for approximately 60% of PM10 emissions and 45% of PM2.5 emissions. Acoustic agglomeration is researched to be the most effective after-treatment method to control particle pollution. Recent experimental research suggests that at a frequency of around 20 kHz and a sound pressure level of 140 dB, particles can be agglomerated. The kinetic energy of the particles is influenced by the presence of acoustics, and this enhances the collision efficiency between the particles. These collided fine particles increase in size and can be easily filtered through conventional filters. Additionally, clean burning biofuels produce comparatively fewer particles; hence RME is used for experiments along with its two blends of isopropanol (RME95I5 and RME90I10). The results are then compared to those of standard diesel fuel. With an increase in load, an average reduction of 20% in fine particles is observed along with an increase in large-sized particles. The aggregation of smaller particles is observed in a range of 0–50% in almost all tested conditions. With the increase in isopropanol from 5 to 10%, oxygen content in the fuel increased by 7%, a 1% reduction in carbon and a 2% reduction in C/H ratio is observed which led to a 6 and 9% reduction in particle emissions at 60 Nm and 90 Nm, respectively. At higher loads, D100, RME95I5 and RME90I10 recorded an agglomeration of 10%, 111% and 189%, respectively. Similar results are observed for the tendency for agglomeration at lower loads. Full article

Hydrotreated vegetable oil (HVO) is a second-generation biofuel with physicochemical properties similar to conventional diesel. Composed mainly of n-paraffins, it offers favorable autoignition characteristics. Produced by hydrotreating vegetable oils or animal fats, including waste sources such as used cooking oil, HVO contributes to lower greenhouse gas emissions and waste utilization. Thanks to its similarity to diesel, it can be used directly or in blends without engine modifications. Blending reduces fossil fuel use and pollutant emissions while maintaining engine performance. This study investigates the autoignition behavior of diesel, neat HVO, and HVO–diesel blends containing 25%, 50%, and 75% HVO by volume. Experiments were conducted in a constant-volume combustion chamber at 550 °C and 650 °C to simulate engine-relevant conditions. Autoignition quality was assessed using ignition delay, combustion delay, average and maximum pressure rise rate, maximum pressure rise, apparent heat release rate, and derived cetane number. The results show that higher HVO content increases the sensitivity of ignition delay, combustion delay, and average pressure rise rate to lower chamber temperature. In addition, a linear increase in derived cetane number was observed with increasing HVO concentration, providing new insights into ignition and combustion behavior of renewable fuel blends. Full article

Engine knock remains a critical limitation in spark-ignition engine design. Future hybrid powertrains employ downsized engines operating on Atkinson cycles, creating different knock conditions compared to modern naturally aspirated or turbocharged engines. At the same time, petroleum-based gasoline is increasingly being replaced by biofuels and electrofuels. This study evaluates knock behavior in projected hybrid engine architectures and examines the chemical composition of emerging fuel blends. The analysis shows that hybrid engines benefit from fuels with lower sensitivity, defined as the difference between the Research and Motor Octane Numbers. This is because the higher end-gas temperatures associated with the Atkinson cycle shift the value of K, which is an interpolation factor used to capture the relationship between fuel sensitivity and anti-knock performance. In conventional engines, K is negative, favoring fuels with higher sensitivity. In hybrid engines, the increased engine temperatures result in K becoming positive, favoring low-sensitivity fuels. Using low-sensitivity fuels allows hybrid engines to operate with higher geometric compression ratios and advanced thermodynamic cycles while reducing knock constraints. Biofuels and electrofuels can meet these requirements by producing paraffinic and naphthenic hydrocarbons with high octane quality and low sensitivity. These findings emphasize the need to align renewable fuel development with hybrid engine requirements to improve thermal efficiency, reduce emissions, and reduce reliance on energy-intensive refinery processes for octane enhancement. Full article

Producing solid biofuels with high calorific value and high storage stability under limited energy consumption has become a crucial focus in the global energy field. Low temperature torrefaction below 300 °C is a common method for producing solid biofuels. However, this approach limits the carbon content and higher heating value (HHV) of the resulting biochar. Sodium percarbonate is a solid oxidant that can assist in the pyrolysis of organic molecules during the torrefaction to increase carbon content of biochar. Incorporating sodium percarbonate as a strategic additive presents a viable means to address the constraints associated with the torrefaction technologies. This study blended sodium percarbonate with spent coffee grounds (SCGs) to prepare torrefied SCG solid biofuels with high calorific value and high carbon content. Based on the Taguchi method with L9 orthogonal arrays, torrefaction temperature is identified as the most influential factor affecting higher heating value (HHV). Results from FTIR, water activity, hygroscopicity, and mold observation confirmed that torrefied SCGs blended with 0.5 wt% sodium percarbonate (0.5TSSCG) exhibited good storage stability. They were not prone to mold growth under ambient temperature and pressure. 0.5TSSCG with a carbon content of 61.88 wt% exhibited a maximum HHV of 29.42 MJ∙kg⁻¹. These findings indicate that sodium percarbonate contributes to increasing the carbon content and HHV of torrefied SCGs, enabling partial replacement of traditional coal consumption. Full article

This study explores the use of a novel heterogeneous CoZnFe₄O₈ nanocatalyst for biodiesel production from a sustainable and innovative blend of waste cooking oil and neem oil feedstock. Utilizing waste cooking oil and inedible neem oil feedstock to produce biodiesel provides a green and economical way to produce renewable and environmentally friendly fuel while simultaneously reducing waste and valorizing inedible oils. Additionally, this feedstock blend does not threaten food or land resources as opposed to feedstocks obtained from edible resources. To fulfill the rising demand for biodiesel and address issues related to lower ester yields, particularly when utilizing waste cooking oils with high free fatty acid concentration, there is an urgent need for more effective processes, including two-stage transesterification. The novel CoZnFe₄O₈ nanocatalyst employed in this study demonstrated high efficiency in biodiesel production thanks to its high surface area, mesoporous structure, and catalytic properties. The effect of key process parameters, including catalyst concentration, reaction time, alcohol-to-oil molar ratio, and oil blend ratio, was investigated to evaluate the performance of the nanocatalyst and optimize the biodiesel yield with the help of Response Surface Methodology (RSM). The optimized process achieved a yield of 94.23% under optimum parameters of 2.13 wt% catalyst, 6.80:1 methanol-to-oil ratio, 4 h, and a ratio of waste cooking oil to neem oil of 98.32:1.68. The predicted and experimental values were in close agreement, indicating that the model was adequate. Additionally, detailed catalyst characterization, including analysis of the surface area, structure, and thermal stability, was carried out. Similarly, the biodiesel was characterized to assess its quality through heating value, density, Fourier Transform Infrared (FTIR) spectroscopy, and ultimate analysis. The recovery and reusability of the nanocatalyst were also investigated, highlighting its potential for multiple reaction cycles. The novel CoZnFe₄O₈ nanocatalyst and innovative feedstock blend demonstrated high efficiency in biodiesel production comparable to other nanocatalysts and feedstocks reported in the literature, highlighting their potential as an efficient and sustainable method to produce biofuels. Full article

This study aimed to assess the physical, chemical, and combustion properties of pellets made from corncob and rice husk residues sourced in Sucre, Colombia, and to evaluate the performance of different blending ratios. Before pelletization, the residues were ground and processed using a small-scale flat die pellet mill equipped with a 6 mm die. Physical properties were evaluated according to ISO standards for particle density, bulk density, and impact resistance assessment. Proximate and ultimate analyses, as well as heating values, were determined and compared against the ISO 17225-6:2021 classification for herbaceous biomass. The 70:30 corncob-to-rice husk blend (CC70:RH30) showed good quality, with 7.23% ash, 9.18% moisture, and an LHV of 15.19 MJ/kg, meeting the criteria for Class B pellets. Combustion performance was assessed using a custom-designed macro-TGA, revealing that co-pelletized blends exhibited improved ignition temperatures and comprehensive combustion indices compared to the individual feedstocks. Additionally, calorific values were proportional to the blending ratios. In summary, controlling the blending ratio of corncob and rice husk residues during pellet production allows modulation of both the total ash content and the lower heating value of the resulting solid biofuels, making them more suitable for thermochemical conversion routes such as combustion and/or gasification. Full article

Macauba is a versatile palm and has been explored in various sectors due to its ability to produce oils, proteins, energy, and biofuels. This paper presents the extraction, refining, and characterization of the macauba kernel oil, the synthesis of biodiesel, and an evaluation of the density and viscosity of its blends with mineral diesel, ranging from B15 to B20. Conversion was determined using the integral areas of the ¹H NMR spectrum for the FAME methyl ester (3.62, -CH₃) and FAME carbonyl (2.26, -COOCH₂). Predictions of the key inputs required for the extraction and degumming of the macauba kernel oil, as well as for the biodiesel production, are also presented. These results provide valuable insights into diesel-biodiesel blends exceeding 14% (vol.) of biodiesel, thereby contributing to the expansion of the biofuels industry. Full article

In the pursuit of sustainable and circular energy sources, this study examines the potential of tire pyrolysis oil (TPO) as a diesel fuel substitute when combined with hydrotreated vegetable oil (HVO), a second-generation biofuel. At varying TPO-HVO blend percentages, this investigation evaluates engine performance and emissions in relation to critical fuel parameters, including density, viscosity, and lubricity. The high-frequency reciprocating rig (HFRR) method was employed to examine tribological aspects, and a single-cylinder diesel engine was tested under various load conditions. The findings indicated that blends containing up to 30% TPO maintained sufficient lubrication and engine performance to comply with diesel standards, concurrently reducing carbon monoxide and smoke emissions. The increase in TPO proportion resulted in a decrease in cetane number, an increase in NOx emissions, and a rise in viscosity, particularly under full engine load conditions. The utilization of TPO is crucial for converting tire waste into fuel, as it mitigates the accumulation of tire waste and reduces dependence on fossil fuels, despite existing challenges. This study provides critical insights into the efficacy of blending methods and underscores the necessity of additional fuel refining processes, such as cetane enhancement and desulfurization, to facilitate their integration into transportation energy systems. Full article

Hydrotreated Vegetable Oil (HVO) is one of the solutions for replacing fossil diesel with a clean and renewable fuel in compression ignition (CI) engines. This study focuses on the benefits of using HVO-fueled engines in Brazil concerning CO₂ emissions, compared with other alternatives in the Brazilian energy matrix. The analysis includes CO₂ emissions from the Brazilian diesel fleet over the last 10 years considering conventional diesel fuel, traditional biofuels, and the anticipated introduction of HVO into the Brazilian market. The proposal involves neat HVO as well as blends of fossil diesel, biodiesel, and HVO (up to 50% by vol.), these blends being more realistic for their practical deployment. Considering the Brazilian diesel fleet over the past 10 years (2015–2025), net CO₂ emissions would have been reduced by 77.4% if 100% HVO had been used, while a reduction of 54.4% would have occurred with the blend containing 50% of HVO. Moreover, the use of 100% HVO for this fleet from 2015 would lead to 366.5 and 652.4 Mton of CO₂ in 2030 and 2035, respectively, compared with 1621.5 and 2885.9 Mton if 100% fossil diesel is used. The economic analysis suggests that fuel cost savings of approximately 12 USD billion could be reached in 2035 under favorable HVO production scenarios. This is a favorable projection, with positive values for all blends and pure HVO, indicating economic feasibility. Full article

Varshavskii’s ‘Diffusion Theory’, less investigated due to its limited international visibility, can offer one of the simplest and, on the other hand, high-accuracy methods for evaluating the ignition delay of fossil fuel and biofuel droplets, including their blend. In this study, experimental pre-tests were conducted to determine pre-existing subject knowledge on stationary droplet combustion at ambient pressure and temperatures varying from 935 to 1010 K followed by simulation of droplet ignition times. The test fuels were mineral diesel (DF), RME and a 20% RME blend with DF. Simulations were performed for isobaric conditions. Using the detailed transport model and detailed chemical kinetics, the necessary rearrangements were made for the governing equations to meet the criteria for modern fuels (biodiesel, diesel, and blend). The influence of different physical parameters, such as droplet radius, or initial conditions, on the ignition delay time was investigated. The high sensitivity of the proposed methodology to experimental results was substantiated. Full article

This research work seeks to introduce eco-friendly, low-carbon, and high-octane biofuel gasoline production using a synergistic approach. Four types of high-octane gasoline, including SynergyFuel-92, SynergyFuel-95, SynergyFuel-98, and SynergyFuel-100, were generated, emphasizing the deliberate combination of petroleum-derived gasoline fractions using reformate, isomerate, and delayed coking (DC) naphtha with octane-boosting compounds—bio-methanol and bio-ethanol. A set of tests have been performed to examine the effects of antiknock properties, density, oxidation stability, distillation range characteristics, hydrocarbon composition, vapor pressure, and the volatility index on gasoline blends. The experimental results indicated that the gasoline blends made from biofuel (SynergyFuel-92, -95, -98, and 100) showed adherence to important fuel quality criteria in the USA, Europe, and China. These blends had good characteristics, such as low quantities of benzene and sulfur, regulated levels of olefins and aromatics, and good distillation qualities. By fulfilling these strict regulations, Synergy Fuel is positioned as a competitive and eco-friendly substitute for traditional gasoline. The results reported that SynergyFuel-100 demonstrated the strongest hot-fuel-handling qualities and resistance to vapor lock among all the mentioned Synergy Fuels. Finally, the emergence of eco-friendly, low-carbon, and high-octane biofuel gasoline production with synergistic benefits is a big step in the direction of sustainable transportation. Full article

With the implementation of the ISO 8217-2024 marine fuel standard, the use of high-concentration biofuels in ships has become viable. However, relatively few studies have been conducted on the effects of biofuels on cylinder lubrication performance in low-speed, two-stroke marine diesel engines. In this study, catering waste oil was blended with 180 cSt low-sulfur fuel oil (LSFO) to prepare biofuels with volume fractions of 24% (B24) and 50% (B50). These biofuels were evaluated in a MAN marine diesel engine under load conditions of 25%, 50%, 75%, and 90%. The experimental results showed that, at the same engine load, the use of B50 biofuel led to lower kinematic viscosity and oxidation degree of the cylinder residual oil, but higher total base number (TBN), nitration level, PQ index, and concentrations of wear elements (Fe, Cu, Cr, Mo). These results indicate that the wear of the cylinder liner–piston ring interface was more severe when using B50 biofuel than when using B24 biofuel. For the same type of fuel, as the engine load increased, the kinematic viscosity and TBN of the residual oil decreased, while the PQ index and the concentrations of Fe, Cu, Cr, and Mo increased, reflecting the aggravated wear severity. Ferrographic analysis further revealed that ferromagnetic wear particles in the oil mainly consisted of normal wear debris. When using B50 biodiesel, a small amount of fatigue wear particles were detected. These findings offer crucial insights for optimizing biofuel utilization and improving cylinder lubrication systems in marine engines. Full article

In this study, a response surface methodology (RSM) using a central composite design (CCD) was implemented to investigate the influence of process variables on ethyl levulinate (EL) production from the ethanolysis of waste corn cob samples, using sulphuric acid as a catalyst. The effects of four independent variables, namely, the temperature (A), the corn cob content (B), corn cob/H₂SO₄ mass ratio (C) and the reaction time (D) on the yields of EL (Y₁), diethyl ether (DEE) (Y₂) and solid residue (Y₃) were explored. Using multiple regression analysis, the experimental results were fitted to quadratic polynomial models. The predicted yields based on the fitted models were well within the experimental uncertainties. Optimum conditions for maximising the EL yield were found to be 176 °C, 14.6 wt. %, 21:1 and 6.75 h for A to D, respectively. A moderate-to-high EL yield (29.2%) from corn cob was achieved in optimised conditions, a result comparable to those obtained from model C₆ carbohydrate compounds. Side products were also produced, including diethyl ether, furfural, levulinic acid, 5-hydroxymethyl furfural, ethyl acetate, ethyl formate and water. Total unknown losses of only 5.69% were reported after material balancing. The results suggest that lignocellulosic waste such as corn cob can be used as a potential feedstock for the production of ethyl levulinate by direct acid-catalysed ethanolysis, but that the treatment of side products will need to be considered. Full article

Biofuels, such as ethanol (CH₃CH₂OH), remain significantly underutilized globally despite their potential to mitigate environmental effects associated with fossil fuel combustion. Ethanol (ETH) can seamlessly blend with petroleum-derived gasoline, boosting its octane rating as a virtuous side effect. However, in several countries, octane number (ON) boosters such as methyl-tert-butyl-ether (MTBE) are still blended into the gasoline (also known as gas or petrol) sold in fuel stations, despite this being restricted or banned due to deleterious effects on the environment and health. Additionally, in nations overproducing naphtha from refining petroleum condensates, such as in the Middle East, investments in extra carbon chain rearrangement units can be an outlet to enhance gasoline production, since they produce high-ON streams; however, aromatic concentration becomes a limiting constraint. A discrete-event simulation algorithm combines sixteen main (primary) manufacturing variations into two secondary manufacturing and three supply chain variations, building gasoline yield and property plots over 512 gasoline production scenarios. Full article

The transition to sustainable energy systems necessitates the development of cleaner fuel alternatives for compression ignition (CI) engines, which continue to play a vital role in transportation and power generation. This study explores the potential of hybrid fuel blends comprising biofuels, hydrogen, ammonia, and synthetic fuels to enhance engine performance while minimizing environmental impact. By reviewing recent advancements, the paper analyzes the combustion characteristics, emissions behavior, and feasibility of various fuel combinations. Biofuel–hydrogen blends improve flame speed and reduce carbon emissions, while ammonia offers zero-carbon combustion when paired with more reactive fuels, like biodiesel or hydrogen. Synthetic fuels, particularly those derived from renewable sources, provide high-quality combustion with low particulate emissions. Hybridization strategies leverage the strengths of each component fuel, resulting in synergistic effects that enhance thermal efficiency, reduce greenhouse gas emissions, and support the continued use of CI engines in a carbon-constrained future. The findings indicate that with proper optimization of fuel formulations and engine technologies, hybrid fuels can play a key role in achieving sustainability goals and reducing fossil fuel dependency. Full article