Search Results (14)

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

This research follows the principles of circular economy through the zero waste concept and cascade approach performed in two steps. Our paper focuses on the first step and explores the characteristics of developed biocomposite materials made from a biodegradable poly(lactic acid) polymer (PLA) reinforced with natural fibers isolated from the second generation of biomass (agricultural biomass and weeds). Two plants, Spartium junceum L. (SJL) and Sida hermaphrodita (SH), were applied. To enhance their mechanical, thermal, and antimicrobial properties, their modification was performed with environmentally friendly additives—linseed oil (LO), organo-modified montmorillonite nanoclay (MMT), milled cork (MC), and zinc oxide (ZnO). The results revealed that SH fibers exhibited 38.92% higher tensile strength than SJL fibers. Composites reinforced with SH fibers modified only with LO displayed a 27.33% increase in tensile strength compared to neat PLA. The addition of LO improved the thermal stability of both biocomposites by approximately 5–7 °C. Furthermore, the inclusion of MMT filler significantly reduced the flammability, lowering the heat release rate to 30.25%, and enabling the categorization of developed biocomposite in a group of flame retardants. In the second step, all waste streams generated during the fibers extraction process are repurposed into the production of solid biofuels (pellets, briquettes) or biogas (bio)methane. Full article

The use of mixed matrix membranes (MMMs) to facilitate the production of biofuels has attracted significant research interest in the field of renewable energy. In this study, the pervaporation separation of butanol from aqueous solutions was studied using a series of MMMs, including zeolitic imidazolate frameworks (ZIF-8)-polydimethylsiloxane (PDMS) and zinc oxide-PDMS mixed matrix membranes. Although several studies have reported that mixed matrix membranes incorporating ZIF-8 nanoparticles showed improved pervaporation performances attributed to their intrinsic microporosity and high specific surface area, an in-depth study on the role of ZIF-8 nanoparticle size in MMMs has not yet been reported. In this study, different average sizes of ZIF-8 nanoparticles (30, 65, and 80 nm) were synthesized, and the effects of particle size and particle loading content on the performance of butanol separation using MMMs were investigated. Furthermore, zinc oxide nanoparticles, as non-porous fillers with the same metalcore as ZIF-8 but with a very different geometric shape, were used to illustrate the importance of the particle geometry on the membrane performance. Results showed that small-sized ZIF-8 nanoparticles have better permeability and selectivity than medium and large-size ZIF-8 MMMs. While the permeation flux increased continuously with an increase in the loading of nanoparticles, the selectivity reached a maximum for MMM with 8 wt% smaller-size ZIF-8 nanoparticle loading. The flux and butanol selectivity increased by 350% and 6%, respectively, in comparison to those of neat PDMS membranes prepared in this study. Full article

Although many biofuel blends have been proposed recently, comparisons of such blends are rarely investigated. Currently, it is extremely difficult to recommend one biofuel blend over another since comparisons are not carried out under the same engine conditions. In the current study, different biofuel blends in dual and ternary issues are compared together, as well as with conventional gasoline under the same engine conditions. Five different biofuel blends are considered, i-butanol (iB), n-butanol (nB), bio-ethanol (E), n-butanol–bio-ethanol (nBE), and i-butanol–bio-ethanol–gasoline (iBE) blends, at two different engine speeds (2500 and 3500 rpm/min). Additionally, the blends are compared in the average bases through wide engine speeds. The comparisons of blends are carried out via engine performance and emissions. The performance includes engine power, torque, and volumetric efficiency, while the emissions include CO, CO₂, and UHC. Results showed that the E blends presented higher performance than the pure/neat gasoline by about 6.5%, 1.5%, and 25% for engine power, torque, and volumetric efficiency, respectively. Nevertheless the other four blended fuels (nB, iB, nBE, and iBE) presented lower levels of engine performance than the pure gasoline by about −3.4%, −2.6%, −5.2%, and −2.3% for engine power, −1.48%, −0.9%, −1.9%, and −1.7% for torque, and −3.3%, −3%, −2.4%, and −2.7% for volumetric efficiency, respectively. Regarding emissions, the E blends presented the highest CO₂ (by about 4.6%) and the lowest CO (by about −20%), while both nB and iB showed the lowest CO₂ (by about −35% and −36%, respectively) and the highest CO emissions (by about −10% and −11.6%, respectively). Lastly, iB and nBE introduced, respectively, the highest and the lowest UHC emissions (by about −6.8% and −17%, respectively) among all blends. Full article

The emissions from direct injection (DI) diesel engines remain a serious setback from the viewpoint of environmental pollution, especially for those who have been persuaded to use biofuel as an alternative fuel. The main drawbacks of using biofuels and their mixtures in DI diesel engines are increased emissions and decreased brake thermal efficiency (BTE) compared to using neat diesel fuel. The current study analyses the biodiesel made from cashew nut shell liquid (CNSL) using a single-cylinder, direct-injection diesel engine to validate the engine’s performance and discharge characteristics. In addition to the improved CNSL and a twin-fuel engine that runs on hydrogen, ethanol was added to the fuel at rates of 5%, 10%, and 15%. The investigation was conducted using a single-cylinder direct injection diesel engine at steady-state settings, above the sustained engine speed (1500 RPM). Several performance parameters and pollutant emissions, such as hydrocarbons (HC), carbon monoxide (CO), and nitrogen oxides (NO_X) were tracked during this study. According to the experimental findings, the biodiesel mixture’s brake heat was reduced by 26.79% in comparison to the diesel fuel. The brake-specific fuel consumption (BSFC) declined with the addition of hydrogen to the CNSL mixture. An increase in the BTE with increasing concentrations of hydrogen in the CNSL fuel blend was observed. The best blends of ethanol and CNSL–hydrogen perceptibly increased the exhaust gas temperature and NO_X emissions, while also producing the fewest HC and CO emissions. The current research acts as a novel paradigm that makes it possible to comprehend the exergy related to mass or energy exchanges as a by-product of thermodynamic quality and quantity. Full article

Diesel engines are one of the most popular reciprocating engines on the market today owing to their great thermal efficiency and dependability in energy conversion. Growing concerns about the depletion of fossil resources, fluctuating prices in the market, and environmental issues have prompted the search for renewable fuels with higher efficiencies compared with conventional fuels. Fuel derived from vegetable oils and animal fats has comparable characteristics to diesel fuel, but is renewable, despite being manufactured from various feedstocks. Nevertheless, the direct use of these fuels is strictly prohibited because it will result in many issues in the engine, affecting engine performance and durability, as well as emissions. To make biofuels as efficient as fossil fuels, it is essential to alter their characteristics. The use of emulsification techniques to obtain emulsified biofuels is one of the many ways to modify the fuel characteristics. Emulsification techniques allow for a decrease in viscosity and an increase in atomisation during injection. To date, emulsification techniques have been studied less thoroughly for use with vegetable oils and animal fats. This article will discuss the preparation and characterisation of emulsified biofuels made from vegetable oils and animal fats. This current paper reviewed research studies carried out on different emulsification techniques for biofuels used in diesel engines. Full article

This paper refers to the study of biofuel as an alternative power source for turbine aviation engines. Blends of Jet A-1 fuel and synthesized hydrocarbons from Hydrotreated Esters and Fatty Acids (HEFA) technology at different proportions, such as 25%, 50% and 75%, were used for tests. All the test results were compared with the neat Jet A-1 fuel. A miniature GTM series turbojet engine was used in the test rig studies. During the tests conducted at a specific rotational speed, selected engine operating parameters as well as the emission of volatile organic compounds were measured. In terms of engine performance, no significant differences were found between the test fuels. The results of volatile organic compound emissions indicate that among the most toxic compounds the highest concentrations were obtained for benzene. The addition of the HEFA synthetic component and increasing its proportion in the blend resulted in the obtained concentration values for benzene showing a decreasing trend. The plotted utility profile indicates that the most optimal blend, i.e., the least toxic, is the blend with the share (v/v) of 62.5% of Jet A-1 fuel and 37.5% of HEFA component. Full article

The aggressive growth of Eichhornia crassipes (Water Hyacinth) plants causes severe damage to the irrigation, environment, and waterway systems in Iraq. This study aims to produce, characterize, and test biofuel extracted from the Eichhornia crassipes plant in Iraq. The extracted biodiesel was mixed at 10%, 20%, and 40% with neat diesel to produce three biodiesel samples. The methodology consists of the physiochemical properties of the samples that were characterized. The performance of the IC engine fueled by neat and biodiesel samples was measured under various operational conditions. The exhaust gases were analyzed to estimate the compounds to assess the environmental impact. The results showed that the density and viscosity of mixtures increase and the calorific value decrease with biodiesel. The engine test showed that the diesel + 10BE, diesel + 20BE, and diesel + 40BE enhanced brake thermal efficiency using 2.6%, 4.2%, and 6.3%, respectively, compared to neat diesel. Exhaust tests show a slight reduction, of 0.85–3.69% and 2.48–6.93%, in CO and HC emission, respectively. NOx is higher by 1.87–7.83% compared with neat diesel. The results revealed that biodiesel blended from Eichhornia crassipes is a viable solution to mitigate the drastic impact on the environment and economy in Iraq. The blended biodiesel has good potential to be mixed with the locally produced diesel from oil refineries. Full article

As the environment is humiliated at a disturbing rate, most governments have persistent calls following global energy policies for the utilization of biofuels. This paper essentially examines the portrayal investigations of fatty acid methyl esters and fatty acid pentyl esters obtained from palm oil. The characterization studies such as gas chromatogram, mass spectrometry, and Fourier transformed infrared spectrometry have been performed to study biodiesel’s chemical composition. This article likewise shows biodiesel’s physiochemical properties and concentrates on biodiesel blends’ hypothetical combustion properties with Al₂O₃ nanoparticles. The spectroscopic investigations demonstrate the contiguity of eight methyl esters and five pentyl esters prevalently of palmitic acid, oleic acid, octanoic acid, and stearic acid. The esters’ nearness was additionally affirmed by the FTIR range, where the peaks in the scope of 1700 cm⁻¹ to 1600 cm⁻¹ can be observed. Looking at the thermophysical properties of the mixes with that of the base diesel fuel yielded the compromising results by giving the comparative density to that of the diesel fuel. The palm oil biodiesel’s calorific value is, by all accounts, diminished by 10% when contrasted with diesel fuel. The addition of the nanoparticles up to 1 g has raised the calorific value most closely to the diesel’s value. Correspondingly, the theoretical burning examinations have demonstrated the limit of biodiesel to go about as an option compared to consistent diesel in the conventional DI–CI engine. This article talks about the combustion attributes of the blend containing 60% diesel, 20% fatty acid methyl ester (FAME), and 20% fatty acid pentyl ester (FAPE) with aluminium oxide (Al₂O₃) nanoparticles at two distinctive concentrations. This article primarily concerns the inquiry of combustion criterion, such as in-chamber pressure variation, rate of heat release, start of combustion, end of combustion, and ignition delay for considered fuel blends when contrasted with neat diesel fuel in a four-stroke, direct-injection, single-cylinder diesel engine. The results showed a decrease in in-cylinder pressure at all loads of engine operation for biodiesel blends when compared with neat diesel, irrespective of the nanoparticle concentration. Biodiesel blends at all nanoparticle concentrations showed an increase in ignition delay compared with diesel fuels at all engine operation loads. The performance results show a slight deterioration in the engine’s thermal efficiency using biodiesel blends, irrespective of the nanoparticle concentration. Additionally, the emissions show a considerable fall in trends for all loads in contrast with diesel fuel. Full article

The fine particulate matter (PM) emitted from jet aircraft poses a serious threat to the environment and human health which can be mitigated by using biofuels. This paper aims to quantify PM emissions from a small turbofan fueled with the alcohol to jet (ATJ) synthetic kerosene and its various blends (5%, 20%, and 30% of ATJ) with Jet A-1 fuel. Emissions from a turbofan engine (DGEN 380) with a high bypass ratio, applicable in small private jets, were studied. Among the four fuels tested, the PM-number emission index (EI_N) was the lowest for the ATJ 30% blend. EI_N for ATJ 30% dropped from 1.1 × 10¹⁷ to 4.7 × 10¹⁶ particles/kg of fuel. Burning alternative fuel blends reduced the particle mass emissions over the entire range of fuel flow by at least 117 mg/kg of fuel. The particles formed in the nucleation mechanism dominate PM emission, which is characteristic of jet engines. Thus, number-based particle size distributions (PSDs) exhibit a single mode log-normal distribution. The highest values of EI_N were found for Jet A-1 neat compared to other fuels. The use of the ATJ additive did not cause significant changes in the size of the particles from nucleation mode. However, a magnitude reduction of nucleation mode was found with the increase in the ATJ ratio. Full article

Sustainable green biofuels could replace a significant amount of fossil fuels responsible for environmental pollution. In this study, waste cooking oil (WCO) was tested in a diesel engine either neat or blended separately with diesel, butanol and gasoline, with an additive concentration between 10% and 30% by volume. The heating values of the WCO were slightly decreased when blended with butanol, whereas they increased when blended with either gasoline or diesel. The flash point temperatures decreased. All fuel samples were non-corrosive and non-acidic. At full load, the brake specific fuel consumption of the WCO–additive fuels was approximately 1–3% higher than diesel. The thermal efficiency of the neat WCO, neat diesel and WCO–10% diesel were very close to each other, whereas, in the case of 20% butanol blend, the efficiency decreased by about 2% when compared to the neat diesel value. The WCO–butanol fuel gave the lowest NO_x emission and a 0.6% lower CO₂ emission than diesel. Combustion characteristics results showed stable engine operation for all blends. The combustion duration was maximal with WCO–butanol blends. The study concluded that the WCO with 10–20% butanol or fossil diesel exhibited similar performance and emission characteristics observed for neat fossil diesel. Full article

The global concentration of greenhouse gasses in the atmosphere is increasing as well as the emissions of harmful pollutants. Utilization of liquid biofuels in combustion engines helps to reduce these negative effects. For diesel engines, the most common alternative fuels are based on vegetable oils. Blending neat vegetable oils with diesel and/or alcohol fuels is a simple way to make them suitable for diesel engines. In this study, coconut oil was used in ternary fuel blends with diesel and butanol. Coconut oil is a potentially usable source of renewable energy, especially in the Pacific, where it is a local product. Diesel fuel-coconut oil-butanol fuel blends were used in concentrations of 70%/20%/10% and 60%/20%/20%, and 100% diesel fuel was used as a reference. The effect of the fuel blends on the production of harmful emissions, engine smoke, performance parameters, fuel consumption and solid particles production was monitored during the measurement. The engine was kept at a constant speed during the measurement and the load was selected at 50%, 75% and 100%. From the results, it can be stated that in comparison with diesel fuel, specific fuel consumption increased with a positive effect on the reduction of engine smoke. Full article

Physico-chemical properties of microalgae biodiesel depend on the microalgae species and oil extraction method. Dioctyl phthalate (DOP) is a clear, colourless and viscous liquid as a plasticizer. It is used in the processing of polyvinyl chloride (PVC) resin and polymers. A new potential biofuel, hydrothermally liquefied microalgae bio-oil can contain nearly 11% (by mass) of DOP. This study investigated the feasibility of using up to 20% DOP blended in 80% diesel fuel (v/v) in an existing diesel engine, and assessed the performance and exhaust emissions. Despite reasonable differences in density, viscosity, surface tension, and boiling point, blends of DOP and diesel fuel were found to be entirely miscible and no separation was observed at any stage during prolonged miscibility tests. The engine test study found a slight decrease in peak cylinder pressure, brake, and indicated mean effective pressure, indicated power, brake power, and indicated and brake thermal efficiency with DOP blended fuels, where the specific fuel consumption increased. This is due to the presence of 16.4% oxygen in neat DOP, responsible for the relatively lower heating value, compared to that of diesel. The emission tests revealed a slight increase in nitrogen oxides (NO_x) and carbon monoxide (CO) emissions from DOP blended fuels. However, particulate matter (PM) emissions were lower from DOP blended fuels, although some inconsistency in particle number (PN) was present among different engine loads. Full article

Neem biodiesel is currently being explored as a future biofuel and was extracted chemically from the vegetable oil. Many of its properties are still under investigation and our aim was to study its noxious-gas emission profiles from blends with regular petroleum diesel. The distinct advantage of a real-time study is acquisition of in situ data on the combustion behavior of gas components with actual progression of time. Mixtures of neem biodiesel and petroleum diesel corresponding to neem additives of 5%, 10%, 15% and 25% were tested for combustion efficiency and emitted gases using a high-performance gas analyzer. Our study, therefore, investigated the overall efficiency of the combustion process linked to emissions of the following gases: O₂, CO₂, NO, NO_x and SO₂. The results for the 95/5% blend compared to the neat sample were most promising and showed no serious change in performance efficiency (<2%). NO/NO_x emission trends displayed maxima/minima, suggestive of interconvertible chemical reactivity. Declining CO and SO₂ emissions were consistent with rapid chemical conversion. The CO and SO₂ concentrations fell well below the toxic atmospheric limits in less than 300 s. The results are generally encouraging for blends below 10%. The potential environmental impact of the study is discussed. Full article