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Due to environmental pollution and global warming, the use of renewable energy sources such as agricultural residues is gaining attention. Corn is the main source of food in many countries, and after harvesting it, the agricultural and industrial sectors generate significant amounts of residues. This study focused on corncob processing, its preparation, and the evaluation of its characteristics for energy needs. There was no significant difference between drying with active ventilation in the dryer and outdoor drying conditions. The adequate moisture content of corncob pellets is 12.39% at a compression ratio of 3.43 ± 0.011 and a maximum pellet density of 1012.96 ± 3.35 kg m−3. The variation in pellet density at a given adequate moisture content is at least 0.78%. The compression ratio of the pellets compacted on the horizontal matrix granulator is 9.75% higher than that of the pellets produced on the laboratory automatic press. The corncob's lower calorific value was 17.35 ± 0.14 MJ kg−1, and the ash content was 1.78 ± 0.24%. The produced pellets are strong enough and can be used for combustion. This research may help to better understand the properties of corncobs and their energy potential. [ABSTRACT FROM AUTHOR]

The present study focuses on the novel synthesis of cerium oxide (CeO 2) nanoparticles from cerium nitrate hexahydrate by using Azadirachta indica (neem) leaf extract. The parameters associated with the green synthesis process were optimized utilizing the response surface methodology (RSM) paired with the genetic algorithm (GA) to produce a higher yield rate. The experiment run order for the CeO 2 green synthesis is then generated using the central composite design in RSM. The regression equation was used as an optimization function, and the optimal values were identified through GA. Using optimized input process parameters, 0.3 g/10 mL of precursor concentration and 5 mL of Azadirachta indica leaf extract centrifuged for 20 min in the green synthesis process resulted in a maximum yield of 15.49 % CeO 2 nanoparticles. The synthesized CeO 2 nanoparticles are characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), energy dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), particle size distribution, and zeta potential analyses, which are used to ensure their presence in the green synthesis process. Subsequently, the green synthesized CeO 2 nanoparticles are dosed as an additive to the cotton seed biodiesel (CSB) at different proportions of 25, 50, and 75 ppm, respectively. The prepared biofuel's physico-chemical properties were measured as per ASTM standards and are closer to the diesel fuel. As a result, it was noted that optimizing the green synthesis process parameters gives a maximum rate of CeO 2 yield. It is possible to efficiently use the CSB with CeO 2 nanoparticles as a suitable replacement for diesel fuel. [Display omitted] • Novel leaf extract for the sustainable synthesis of CeO 2 nanoparticles. • Green synthetic CeO 2 yield forecasted by RSM's central composite design. • A hybrid RSM-genetic algorithm approach to process parameters optimization. • A characterization study was done on environmentally friendly CeO 2 nanoparticles. [ABSTRACT FROM AUTHOR]

Generation of biodiesel from microalgae has been extensively investigated; however, its quality is often not suitable for use as fuel. Our investigation involved the evaluation of biodiesel quality using a native isolateChlorella sorokinianaMIC-G5, as specified by American Society for Testing and Materials (ASTM), after transesterification of lipids with methanol, in the presence of sodium methoxide. Total quantity of lipids extracted from dry biomass, of approximately 410–450 mg g−1was characterized using FTIR and1H NMR. After transesterification, the total saturated and unsaturated fatty acid methyl esters (FAMEs) were 43% and 57%, respectively. The major FAMEs present in the biodiesel were methyl palmitate (C16:0), methyl oleate (C18:1), and methyl linoleate (C18:2), and the1H NMR spectra matched with criteria prescribed for high-quality biodiesel. The biodiesel exhibited a density of 0.873 g cm–3, viscosity of 3.418 mm2s−1, cetane number (CN) of 57.85, high heating value (HHV) of 40.25, iodine value of 71.823 g I2100 g−1, degree of unsaturation (DU) of 58%, and a cold filter plugging point (CFPP) of –5.22°C. Critical fuel parameters, including oxidation stability, CN, HHV, iodine value, flash point, cloud point, pour point, density, and viscosity were in accordance with the methyl ester composition and structural configuration. Hence,C. sorokinianacan be a promising feedstock for biodiesel generation. [ABSTRACT FROM PUBLISHER]

[Display omitted] • Yellow grease enhanced bio-crude yields and lowered asphaltene content. • Feedstock selection can be used to tailor viscosity, density, and compatibility. • Food waste bio-crude showed regions of compatibility at higher concentrations. • Heterogeneous nature of wastes could lead to varied properties and behavior. Low quality waste feedstocks like food wastes, waste fats, manures etc. offer huge potential for replacing an appreciable quantity of petroleum crude. Owing to high water content of some of these feedstocks, hydrothermal liquefaction is the preferred route for its transformation. The present work performed in a continuous pilot scale hydrothermal liquefaction system studies the influence of yellow grease on the yields and quality of bio-crude, properties of bio-crude/blends, and its compatibility with petroleum fractions. Blends of food waste, yellow grease, and algae were used as feedstocks. Key fuel properties such as density and viscosity of bio-crudes and its blends with diesel and butanol were evaluated. Compatibility of different bio-crudes with petroleum fraction was investigated using microscopy imaging of blends of bio-crude and commercial diesel. Enhanced yields of bio-crude and lower asphaltene content were observed with the addition of waste lipids in the form of yellow grease while also decreasing the viscosity and density of bio-crude. Bio-crude from food wastes showed regions of compatibility at higher bio-crude concentrations while lower concentrations of bio-crude were incompatible. A combination of feedstock mix and blending of bio-crude could be used to improve the properties and compatibility of bio-crude for specific end-use devices and processes. [ABSTRACT FROM AUTHOR]

Physical and chemical properties of biodiesel are influenced by structural features of the fatty acids, such as chain length, degree of unsaturation and branching of the carbon chain. This study investigated if microalgal fatty acid profiles are suitable for biodiesel characterization and species selection through Preference Ranking Organisation Method for Enrichment Evaluation (PROMETHEE) and Graphical Analysis for Interactive Assistance (GAIA) analysis. Fatty acid methyl ester (FAME) profiles were used to calculate the likely key chemical and physical properties of the biodiesel [cetane number (CN), iodine value (IV), cold filter plugging point, density, kinematic viscosity, higher heating value] of nine microalgal species (this study) and twelve species from the literature, selected for their suitability for cultivation in subtropical climates. An equal-parameter weighted (PROMETHEE-GAIA) ranked Nannochloropsis oculata, Extubocellulus sp. and Biddulphia sp. highest; the only species meeting the EN14214 and ASTM D6751-02 biodiesel standards, except for the double bond limit in the EN14214. Chlorella vulgaris outranked N. oculata when the twelve microalgae were included. Culture growth phase (stationary) and, to a lesser extent, nutrient provision affected CN and IV values of N. oculata due to lower eicosapentaenoic acid (EPA) contents. Application of a polyunsaturated fatty acid (PUFA) weighting to saturation led to a lower ranking of species exceeding the double bond EN14214 thresholds. In summary, CN, IV, C18:3 and double bond limits were the strongest drivers in equal biodiesel parameter-weighted PROMETHEE analysis.

Two fuel kinds of organic origin including rapeseed methyl ester (RME) and ethanol (E) were selected for their different physical-chemical parameters to study the maximum apt volume of oxygenates to mix fossil diesel (D) and establish expectancy to apply D–RME–E blend as a fuel for the unmodified high–speed diesel engine (a combustion chamber consists of a dished piston). The objective of the article is to provide an explicit relationship between the nature of fuel composition and diesel engine operating parameters. The results of the carried out tests on the engine oriented on dynamic and emission characteristics using various portions of the before mentioned bio-components in diesel fuel are presented. Engine behaviour seemed to be improved in the presence of ethanol additives in D–RME blend with a reduction in pollutant emissions in exhaust gases, fuel consumption, ameliorated cetane number, ignition delay time and physical-chemical characteristics of the investigated compounds. The positive and negative aspects of applying bio-based additives in fossil diesel are reported and discussed.

Complex effectiveness and emission studies were carried out for heating boilers of low heat output, fired with wood fuel. The studies were completed in a series of stages. The first step was directed at the investigation of properties of currently used biofuel made of biomass and potentially perspective biofuel made of agromass in order to determine specific properties and how fuel should be prepared so that it could be efficiently burned in heating boilers. The second stage included numerical and experimental studies of various combustion chambers of heating boilers and air/flue gas canals in order to improve air/combustion product mixing and assuring proper combustion products' presence time in the hot zone and their temperature. During the last stage, the distribution of the particulate matter concentration in combustion products depending on their size and reduction methods of the concentration were analyzed. [ABSTRACT FROM AUTHOR]

The use of organic wastes as new renewable energy sources is becoming necessary to achieve the growing energy demand in Tunisia. In this work, the pyrolysis of abundant waste fish fats provided by a canned Tuna factory was examined in a laboratory fixed-bed reactor. The main objective was to analyze the properties and the composition of the produced bio-oil using in order to implement the suitable valorization strategy. Therefore, high heating value, viscosity, density, flash point, acidity index, moisture content and ash content measurements as well as FTIR and GCMS analyses were carried out to characterize the pyrolytic oil obtained during waste fish pyrolysis at 500 °C. The obtained results revealed that waste fish fats can be considered as important feedstock for biofuel production. In particular, the bio-oil characterization showed the presence of many organic compounds such as alkanes, alkenes, alkynes, cyclic hydrocarbons, carboxylic acids, aldehydes and alcohols. These compounds could be used as a valuable and sustainable chemicals source. Moreover, the bio-oil properties indicated a good calorific value (~ 9391 kcal/kg) compared to Tunisian Diesel and European biodiesel specifications. In contrast, higher acidity (~ 103 mg KOH/g sample) and viscosity (~ 7 cSt) compared to conventional fuels were obtained. These properties limit the direct use of bio-oils as alternative fuel in a Diesel engine. An efficient mixture with fossil fuel may be a promising solution to improve the fuel properties. Hence, pyrolysis seems to be an eco-friendly process to recover the fish fatty wastes in Tunisia. The implementation of such management strategy will help Tunisian agri-food industries to reduce their environmental impact and fossil fuel consumption and to promote the renewable energy use. [ABSTRACT FROM AUTHOR]

Two fuel kinds of organic origin including rapeseed methyl ester (RME) and ethanol (E) were selected for their different physical-chemical parameters to study the maximum apt volume of oxygenates to mix fossil diesel (D) and establish expectancy to apply D–RME–E blend as a fuel for the unmodified high–speed diesel engine (a combustion chamber consists of a dished piston). The objective of the article is to provide an explicit relationship between the nature of fuel composition and diesel engine operating parameters. The results of the carried out tests on the engine oriented on dynamic and emission characteristics using various portions of the before mentioned bio-components in diesel fuel are presented. Engine behaviour seemed to be improved in the presence of ethanol additives in D–RME blend with a reduction in pollutant emissions in exhaust gases, fuel consumption, ameliorated cetane number, ignition delay time and physical-chemical characteristics of the investigated compounds. The positive and negative aspects of applying bio-based additives in fossil diesel are reported and discussed. First published online: 24 Jun 2011

Physical and chemical properties of biodiesel are influenced by structural features of the fatty acids, such as chain length, degree of unsaturation and branching of the carbon chain. This study investigated if microalgal fatty acid profiles are suitable for biodiesel characterization and species selection through Preference Ranking Organisation Method for Enrichment Evaluation (PROMETHEE) and Graphical Analysis for Interactive Assistance (GAIA) analysis. Fatty acid methyl ester (FAME) profiles were used to calculate the likely key chemical and physical properties of the biodiesel [cetane number (CN), iodine value (IV), cold filter plugging point, density, kinematic viscosity, higher heating value] of nine microalgal species (this study) and twelve species from the literature, selected for their suitability for cultivation in subtropical climates. An equal-parameter weighted (PROMETHEE-GAIA) ranked Nannochloropsis oculata, Extubocellulus sp. and Biddulphia sp. highest; the only species meeting the EN14214 and ASTM D6751-02 biodiesel standards, except for the double bond limit in the EN14214. Chlorella vulgaris outranked N. oculata when the twelve microalgae were included. Culture growth phase (stationary) and, to a lesser extent, nutrient provision affected CN and IV values of N. oculata due to lower eicosapentaenoic acid (EPA) contents. Application of a polyunsaturated fatty acid (PUFA) weighting to saturation led to a lower ranking of species exceeding the double bond EN14214 thresholds. In summary, CN, IV, C18:3 and double bond limits were the strongest drivers in equal biodiesel parameter-weighted PROMETHEE analysis. [ABSTRACT FROM AUTHOR]

Two fuel kinds of organic origin including rapeseed methyl ester (RME) and ethanol (E) were selected for their different physical-chemical parameters to study the maximum apt volume of oxygenates to mix fossil diesel (D) and establish expectancy to apply D-RME-E blend as a fuel for the unmodified high-speed diesel engine (a combustion chamber consists of a dished piston). The objective of the article is to provide an explicit relationship between the nature of fuel composition and diesel engine operating parameters. The results of the carried out tests on the engine oriented on dynamic and emission characteristics using various portions of the before mentioned bio-components in diesel fuel are presented. Engine behaviour seemed to be improved in the presence of ethanol additives in D-RME blend with a reduction in pollutant emissions in exhaust gases, fuel consumption, ameliorated cetane number, ignition delay time and physical-chemical characteristics of the investigated compounds. The positive and negative aspects of applying bio-based additives in fossil diesel are reported and discussed. [ABSTRACT FROM AUTHOR]