Search Results (67)

The reliability of power transmission and distribution depends on the proper functioning of power transformers, which use conventional mineral oil as an insulating fluid. The lower fire class and biodegradability of mineral oil have led to a shift towards second-generation oils from vegetable and plant crops. Ester fluids provide a better performance in combination with solid pressboard/paper insulation, increasing the lifetime of power transformers compared to those using mineral oil. Considering the need for sustainability in the near future, second-generation oils are no longer feasible, and hence, third-generation oils derived from microalgae species are suitable alternative fuels for the energy sector. The fatty acid methyl ester (FAME) content of algae is similar to that of biodiesel, making it a suitable fluid for power transformers. A detailed overview of third-generation feedstock (algae) for power transformer applications is provided, focusing on the extraction of algal oil, in conjunction with safety precautions and its fatty acid content, and a comparison with conventional vegetable and plant-based oils is presented. Various properties of algal oil (fatty acid composition, kinematic viscosity, oxidation stability, breakdown voltage, etc.) are analyzed to assess its suitability as a transformer fluid. This review article comprehensively analyzes the current research landscape surrounding the use of algal oil as an insulating fluid in transformers. It critically evaluates both the potential advantages and the unique challenges associated with this alternative to conventional mineral oil and second-generation vegetable and plant-based oils. Full article

This review synthesizes recent research on alternative fuels for piston-engine aircraft and related propulsion technologies. Biofuels show substantial promise but face technological, economic, and regulatory barriers to widespread adoption. Among liquid options, biodiesel offers a high cetane number and strong lubricity yet suffers from poor low-temperature flow and reduced combustion efficiency. Alcohol fuels (bioethanol, biomethanol) provide high octane numbers suited to high-compression engines but are limited by hygroscopicity and phase-separation risks. Higher-alcohols (biobutanol, biopropanol) combine favorable heating values with stable combustion and emerge as particularly promising candidates. Biokerosene closely matches conventional aviation kerosene and can function as a drop-in fuel with minimal engine modifications. Emissions outcomes are mixed across studies: certain biofuels reduce NO_x or CO, while others elevate CO₂ and HC, underscoring the need to optimize combustion and advance second- to fourth-generation biofuel production pathways. Beyond biofuels, hydrogen engines and hybrid-electric systems offer compelling routes to lower emissions and improved efficiency, though they require new infrastructure, certification frameworks, and cost reductions. Demonstrated test flights with biofuels, synthetic fuels, and hydrogen confirm technical feasibility. Overall, no single option fully replaces aviation gasoline today; instead, a combined trajectory—biofuels alongside hydrogen and hybrid-electric propulsion—defines a pragmatic medium- to long-term pathway for decarbonizing general aviation. Full article

The environmental impact of first-generation biodiesel production, particularly deforestation and soil degradation caused by palm and soybean cultivation, has raised concerns about sustainability. In contrast, second-generation biodiesel utilizes waste as feedstock, offering a more sustainable alternative. Used cooking oil (UCO), a significant waste stream, represents a viable feedstock for biodiesel production, reducing pollution and mitigating economic, environmental, and social challenges. While Europe has demonstrated successful UCO waste management strategies, many regions lack efficient systems, leading to improper disposal that causes water eutrophication, soil degradation, and increased wastewater treatment costs. This study develops a comprehensive strategy for UCO management to optimize its energy potential in biodiesel production, using Barranquilla, Colombia, as a case study. Transesterification, identified as the most efficient conversion method, achieves conversion rates of up to 90%. A pilot project in the Barranquilla area estimates that 963,070.95 kg of UCO is generated annually, with the potential to produce 902,108.56 kg of biodiesel. These findings contribute to the advancement of circular economy principles, offering an adaptable framework for sustainable biofuel production in other regions. Full article

As fossil fuel depletion and environmental pollution become increasingly severe, biodiesel has emerged as a promising renewable alternative to conventional diesel due to its biodegradability, low sulfur emissions, and high combustion efficiency. This paper provides a comprehensive review of the evolution of biodiesel feedstocks, major production technologies, and key factors influencing production efficiency and fuel quality. It traces the development of feedstocks from first-generation edible oils, second-generation non-edible oils and waste fats, to third-generation microalgal oils and fourth-generation biofuels based on synthetic biology, with a comparative analysis of their respective advantages and limitations. Various production technologies such as transesterification, direct esterification, supercritical alcohol methods, and enzyme-catalyzed transesterification are examined in terms of reaction mechanisms, process conditions, and applicability. The effects of critical process parameters including the alcohol-to-oil molar ratio, reaction time, and temperature on biodiesel yield and quality are discussed in detail. Particular attention is given to the role of catalysts, including both homogeneous and heterogeneous types, in enhancing conversion efficiency. In addition, life cycle assessment (LCA) is briefly considered to evaluate the environmental impact and sustainability of biodiesel production. This review serves as a valuable reference for improving biodiesel production technologies, advancing sustainable feedstock development, and promoting the commercial application of biodiesel. Full article

This study examines the evolving role of canola biofuel in achieving energy security, analyzing its historical significance, current challenges, and prospects. Once a dominant feedstock for biodiesel production in Europe, canola biofuel is facing a decline in relevance due to the emergence of second- and third-generation biofuels, which offer greater economic and environmental advantages. The research highlights key factors influencing this shift, including high production costs, resource-intensive cultivation, and suboptimal life cycle environmental performance. Through correlation and causality analyses, the study finds no definitive relationship between oil prices and the frequency of scientific publications on canola biofuels, suggesting other drivers, such as policy and technological advancements, play a more significant role. Despite its diminishing prominence, canola biofuel retains value in energy diversification and rural agricultural support, due to geographic, policy, and investment constraints. The findings emphasize the need for prioritizing the development of more sustainable and efficient biofuel technologies to address global energy and environmental challenges. Full article

The production of microbial metabolites such as (exo)polysaccharides, lipids, or mannitol through the cultivation of microorganisms on sustainable, low-cost carbon sources is of high interest within the framework of a circular economy. In the current study, two non-extensively studied, non-conventional yeast strains, namely, Cutaneotrichosporon curvatus NRRL YB-775 and Papiliotrema laurentii NRRL Y-3594, were evaluated for their capability to grow on semi-defined lactose-, glycerol-, or glucose-based substrates and produce value-added metabolites. Three different nitrogen-to-carbon ratios (i.e., 20, 80, 160 mol/mol) were tested in shake-flask batch experiments. Pretreated secondary cheese whey (SCW) was used for fed-batch bioreactor cultivation of P. laurentii NRRL Y-3594, under nitrogen limitation. Based on the screening results, both strains can grow on low-cost substrates, yielding high concentrations of microbial biomass (>20 g/L) under nitrogen-excess conditions, with polysaccharides comprising the predominant component (>40%, w/w, of dry biomass). Glucose- and glycerol-based cultures of C. curvatus promote the secretion of mannitol (13.0 g/L in the case of glucose, under nitrogen-limited conditions). The lipids (maximum 2.2 g/L) produced by both strains were rich in oleic acid (≥40%, w/w) and could potentially be utilized to produce second-generation biodiesel. SCW was nutritionally sufficient to grow P. laurentii strain, resulting in exopolysaccharides secretion (25.6 g/L), along with dry biomass (37.9 g/L) and lipid (4.6 g/L) production. Full article

Waste cooking oils (WCOs) are generated globally in significant amounts by various sectors including hospitality, households, and industrial operations. Many nations currently lack dedicated legislation for managing WCOs, creating a pressing environmental challenge. At present, WCOs are primarily utilized in industries as raw materials for biodiesel production and energy generation. However, their role in second-generation biodiesel production is contingent on availability, often necessitating imports of either biodiesel or WCOs from other countries. The European Union has emphasized the importance of prioritizing biowaste for high-value alternative products beyond biodiesel to achieve carbon neutrality by 2050. Many reviews have been published in the literature reporting potential WCO applications to produce biolubricants, biosolvents, animal feed, asphalt additives, among others, however, no detailed analysis of industrial trends has ever been presented. Within this panorama, unlike existing reviews that focus on specific polymer classes derived from WCOs, this work sought to present a comprehensive industrial overview of the use of WCOs in creating high-value polymeric materials beyond fuel and energy, providing a general overview of patents published (or alive) in the last 10 years, together with the analysis of which innovative products are being introduced and sold on the market today. Full article

Biodiesel is a promising alternative to fossil fuels, offering environmental benefits but facing challenges such as low energy density, poor oxidative stability, and high emissions. Nanotechnology has emerged as a solution, with nanoparticles improving biodiesel properties. This review examines the synthesis, characterization, and application of metal-based, carbon-based, and hybrid nanomaterials in biodiesel. Notable enhancements include an 18% increase in brake thermal efficiency with aluminum oxide and a 20% reduction in NOx emissions with cerium oxide. Hybrid nanoparticles, like graphene oxide with carbon nanotubes, have achieved a 25% decrease in hydrocarbon emissions. Despite these advancements, concerns regarding nanoparticle toxicity, environmental impact, and stability remain. Future research should focus on eco-friendly synthesis, integration with second-generation biodiesel, and multifunctional hybrid nanomaterials. This review highlights the potential of nanotechnology in enhancing biodiesel performance, paving the way for cleaner and more efficient energy solutions. Full article

In recent years, the global demand for energy has been continuously increasing. Biodiesel as a replacement for fossil fuels holds strategic importance for sustainable economic development, mitigating the environmental impact, and managing air pollution. The utilization of second-generation biodiesel has garnered significant research interest due to its physical and chemical characteristics that are comparable to diesel, its elevated cetane number, and its reduced viscosity. This study will transform the TBD234v6 fuel system, transforming the original diesel fuel system into a second-generation biodiesel/diesel hybrid fuel system. This study examined the impacts of second-generation biodiesel on combustion, performance, and emissions in diesel engines, as well as the influence of the deoxygenation rate on second-generation biodiesel. Grey decision-making was used to determine the optimal mixing ratio and deoxygenation rate. The results indicated that the optimal blend comprises 10% second-generation biodiesel and 90% diesel fuel. In dual-fuel mode at this blend ratio, there is a 3% increase in maximum pressure compared to running on pure diesel. Moreover, the fuel consumption rate decreases by approximately 5.6%. Nitrogen oxide (NO_x) and soot emissions decreased by 4.7% and 4.9%, respectively. Full article

In this study, an upflow anaerobic packed-bed reactor (UAPB) produced biobutanol from the main byproduct of biodiesel plants, commonly known as glycerol. Currently, butanol production is mostly limited to pure cultures and sterilized feedstocks. Using glycerol wastes from biodiesel production demands a new paradigm because sterilization is not economically feasible for the elevated amount of glycerol generated by the biodiesel industry. Different microbial consortia were evaluated as inoculum sources to convert glycerol to butanol. In the first stage, operations were carried out with an average organic loading rate (OLR) of 13 g COD L⁻¹ d⁻¹. Kefir grains, sucrose auto-fermentation consortium, and heat-treated anaerobic sludge produced 16.7, 48.5, and 12.8 mg of butanol per gram of chemical oxygen demand (COD), respectively. Besides butanol production, a significant amount of ethanol (241.5 mg g⁻¹ COD), acetate (30.3 mg g⁻¹ COD), and butyrate (183.4 mg g⁻¹ COD) were generated with glycerol processed by sucrose auto-fermentation consortium. In the second stage, the organic loading rates of 6.5, 13.0, and 26.0 g COD L⁻¹ d⁻¹ were applied to the UAPB reactor inoculated with sucrose auto-fermentation consortium. The OLR of 13.0 g COD L⁻¹ d⁻¹ yielded the highest production of butanol (41.5 mg g⁻¹ COD) and generated other valuable co-products such as butyrate (246.1 mg g⁻¹ COD), acetate (37.3 mg g⁻¹ COD), and propionate (19.6 mg g⁻¹ COD). Full article

The imperative of utilising alternative fuels for the operation of internal combustion engines stems from the requirements to reduce the emissions of greenhouse gases and other contaminants, the substantial demand for fuels, and the diminishing reserves of natural resources. The global inclination towards sustainable development necessitates the employment of biofuels as a substitute for fossil fuels. Nonetheless, the expenditures on raw materials for the manufacture of biodiesel remain substantial, thus underlining the importance of exploring solutions for reducing them. An instance of this could be the utilisation of plant and animal by-products, such as used frying oils and slaughterhouse waste, as feedstock for biodiesel production. Not only will this facilitate the creation of less costly biofuel, but it will also provide an effective solution for the management of post-production waste. The objective of the research delineated in this paper was to ascertain select physicochemical attributes of second-generation biodiesel, derived from spent frying oil, as well as mixtures of this biodiesel with diesel and biodiesel concentrations of 10, 20, and 30% (v/v). The biodiesel produced is the waste frying oil methyl esters WFOME. The proprietary GW-201 reactor was employed in the production of biodiesel. For WFOME biodiesel, DF diesel, and their blends—B10, B20, and B30—properties that influence the formation process of the combustible mixture, autoignition, and combustion of fuel–air mixtures in self-ignition engines were determined. The conducted research has established that “B” type fuels prepared from WFOME and DF present a viable alternative to fossil fuels. Pure biodiesel exhibited a marginally reduced lower heating value, however, in the case of fuel mixtures comprising up to 30% (v/v) biodiesel and diesel, the lower heating values approximated that of diesel. An elevated cetane number alongside an increased flash point of pure B100 biodiesel have been noted. The values of cetane number for WFOME and DF mixtures were found to be either comparable or marginally higher than those of pure DF diesel fuel. Full article

In the current study, the cultivation of microalgae on wastewater-based substrates is investigated for an effective natural wastewater treatment that also generates biofuels and value-added products beneficial to human health. Additionally, the health of ecosystems can be evaluated via microalgae. The utilization of microalgae as bioindicators, biofuel producers, and wastewater treatment providers, under the biorefinery concept, is covered in this article. In fact, bioremediation is feasible, and microalgae culture can be used to efficiently process a variety of effluents. Along with wastewater processing and the creation of value-added substances, bioconversion concurrently offers a viable and promising alternative for reducing CO₂ greenhouse gas emissions to contribute to climate change mitigation. The microalgal biorefinery being considered as the third generation is unique in that it addresses all the aforementioned problems, in contrast to lignocellulosic biomass from agricultural waste in second-generation biorefineries and edible crops in first-generation biorefineries. In particular, one of the most promising natural resources for the manufacture of biofuel, including biodiesel, bioethanol, biomethane, and biohydrogen, is found to be microalgae. Furthermore, products of high value, like fatty acid methyl esters, astaxanthin, β-carotene, DHA, and EPA can be made. Hence, microalgal biomass offers a substitute for the development of biofertilizers, bioplastics, pharmaceuticals, cosmetics, animal and aquatic feeds, and human nutrition products, thus promoting human and environmental health. Full article

The results of an experimental study of nitrogen oxide (NO) and particulate matter (PM) concentrations in the exhaust gas of a compression-ignition engine used in agricultural tractors and other commercial vehicles are presented. The engine was fueled with second-generation biodiesel obtained from used frying oils (classified as waste) and first-generation biodiesel produced from rapeseed oil as well as, comparatively, diesel fuel. Tests were conducted on a dynamometer bench at a variable load and a variable engine speed. The levels of PM and NO emissions in the exhaust gas were determined. The study showed significant environmental benefits of using first- and second-generation biodiesel to power the engine due to the level of PM emissions. The PM content, when burning ester biofuel compared to diesel fuel, was reduced by 45–70% on average under the speed and load conditions implemented. As for the concentration of nitrogen oxide in the exhaust gas, no clear trend of change was shown for the biodiesel in relation to the diesel fuel. The level of NO emissions in the range of full-power characteristics was found to be lower for both tested biofuels compared to diesel fuel at lower engine speeds by an average of 7–8%, while in the range of a higher rotation speed, the NO content in the exhaust gases was higher for the tested biofuels compared to diesel oil by an average of 4–5%. The realized engine performance tests, moreover, showed an unfavorable effect of the biodiesel on the engine energy parameters. In the case of biofuels, this was by more than 4% compared to diesel fuel. Full article

India imports fossil fuels to meet its energy needs, and the need is anticipated to increase over the coming years. The constant usage of crude fuel will initiate its depletion in due course, necessitating the hunt for substitute fuels. One of the most promising alternatives to fossil fuels is determined to be biofuels. Fuels made from second-generation feedstocks, particularly non-edible oils, may change the game in this situation. The use of Simarouba non-edible oil as a substitute for diesel in common rail direct injection (CRDI) engines is the subject of the current piece of research. Running a CRDI engine with Simarouba biodiesel blends may not be suitable under the same operating conditions as running a diesel engine. To optimize performance, the ideal conditions for operating a CRDI engine with Simarouba biodiesel mixes needs to be discovered. The control settings in this study that affect the engine’s performance viz., fuel temperature (FPT), fuel injection pressure (IP), and injection time (IT) are designed using the Taguchi technique. Under full load conditions of 12 kg, for the biodiesel blends viz., SB5, SB10, and SB20, studies were conducted using the Taguchi L9 orthogonal array (OA). Through experimentation, performance and emission responses were obtained. For analysis, six engine responses were considered. The analysis shows that each response is uniquely impacted by the engine control parameters. Therefore, it might be challenging to pinpoint the ideal circumstances that would improve performance and lower emissions. Thus, this presents an example of a multi-response optimization problem. For this reason, multiple response optimization uses Taguchi-Grey Relational Analysis (TGRA). According to TGRA, the ideal settings to increase engine performance while using Simarouba biodiesel blends as fuel are an FPT of 40 °C, an IT of 21° bTDC, and an IP of 600 bar. Full article

Poland is an important producer of rapeseed used in the biofuel industry. The rate of production of the biofuel industry increased after Poland’s accession to the European Union (EU). The reasons for these changes are numerous, of which the European Union’s energy policy is the most important. This paper aims to analyze the performance of the biofuel industry in Poland in view of changes in the market. Moreover, I evaluated changes in the biofuel industry after Poland’s accession to the EU. In addition, I analyzed the fixed and current assets of the Polish biofuel. The hypothesis that the price of rapeseed oil is the key determinant of profitability in the biodiesel industry was formulated. A statistical analysis proved the second hypothesis stating that the net profit of biodiesel companies depends on biodiesel production to the greatest extent. The time range of the analysis was 2005–2021. To analyze the economic performance of the biofuel industry in Poland, these changes were used. A regression analysis to find factors influencing the economic performance of the biofuel industry was used. More and more oils are used for the production of first-generation biofuels. Refined rapeseed oil also increased from 386.5 thousand tons to 780.6 thousand tons. Such numbers demonstrate the development of biofuel markets. Full article