Physicochemical Properties of Biodiesel Synthesised from Grape Seed, Philippine Tung, Kesambi, and Palm Oils

Accurate Kinetics of Cyclization Reactions of the Large-Size Hydroperoxy Methyl-Ester Radicals Investigated by the Isodesmic Reaction Correction Method

The cyclization reactions of hydroperoxymethylester radicals are pivotal in low-temperature methyl-ester combustion but limited experimental and theoretical kinetic data pose challenges. Prior research has drawn upon analogous hydroperoxy alkyl radical cyclization reactions to approximate rate constants and might inaccurately represent ester group-specific behavior. This study systematically investigates these kinetics, accounting for ester group effects and computational complexities in large molecular systems. The reactions are categorized into 11 classes based on cyclic transition state size and -OOH/radical positions. Energy barriers and high-pressure-limit rate constants are calculated using the isodesmic reaction correction method, validated, and applied to 24 subclasses based on carbon sites connected to -OOH and radical moieties. Subclass high-pressure-limit rate rules are derived through averaging rate constants. Analysis reveals uncertainties within acceptable chemical accuracy limits, validating the reaction classification and rate rules. We conduct comparative analyses with values from analogous alkyl reactions in established mechanisms while comparing our results with the high-pressure-limit rate rules for analogous alkane reactions. These comparisons reveal notable disparities, emphasizing the ester group's influence and necessitating tailored ester-specific rate rules. These findings hold promise for improving automatic reaction mechanism generation, particularly for large methyl esters.

Membrane reactor for production of biodiesel from nonedible seed oil of Trachyspermum ammi using heterogenous green nanocatalyst of manganese oxide

Conventional homogeneous-based catalyzed transesterification for the production of biodiesel can be replaced with a membrane reactor that has an immobilized heterogeneous catalyst. Combining reaction with separation while utilizing membranes with a certain pore size might boost conversion process. this investigation to study the effectiveness of membrane reactor in combination with heterogeneous green nano catalysis of MnO2. Techniques such as XRD, EDX, FTIR, SEM, and TGA were used to characterize the synthesized MnO2 nano catalyst. The highest conversion of around 94% Trachyspermum ammi oil was obtained by MnO2. The optimum process variables for maximum conversion were catalyst loading of 0.26 (wt.%), 8:1 M ratio, 90 °C reaction temperature, and time 120 min. The green nano catalyst of MnO2 was reusable up to five cycles with minimum loss in conversion rate of about 75% in the fifth cycle. Nuclear magnetic resonance validated the synthesis of methyl esters. It was concluded that membrane reactor a promising technique to efficiently transesterify triglycerides into methyl esters and enable process intensification uses MnO2 as a catalyst.

Comparison of the Engine Performance of Soybean Oil Biodiesel Emulsions Prepared by Phase Inversion Temperature and Mechanical Homogenization Methods

The engine performance and emission characteristics of burning emulsions of soybean oil biodiesel in a compression-ignition diesel engine prepared through the phase inversion temperature method were compared with those of neat soybean oil biodiesel and the emulsion prepared by the mechanical homogenization method. The engine torque was set constantly at 98 N·m with varying engine speeds. The experimental results show that the emulsion prepared by the method of phase inversion temperature had higher O2 and NOx emissions, a higher excess air ratio, a higher exhaust gas temperature, and a higher brake fuel conversion efficiency than the emulsion prepared by the mechanical homogenization method, which had lower CO and CO2 emissions, a lower equivalence ratio, and lower brake-specific fuel consumption. While the neat soybean oil biodiesel was found to have the lowest fuel consumption rate, brake-specific fuel consumption, and CO and CO2 emissions, it had the highest exhaust gas temperature and brake fuel conversion efficiency, NOx and O2 emissions, and excess air ratio among those three fuels. Therefore, the phase inversion temperature method is considered promising for preparing fuel emulsions as an alternative to petro-derived diesel for compression-ignition engines.

Transformation of waste seed biomass of Cordia myxa into valuable bioenergy through membrane bioreactor using green nanoparticles of indium oxide

Depletion of non-renewable fuel has obliged researchers to seek out sustainable and environmentally friendly alternatives. Membranes have proven to be an effective technique in biofuel production for reaction, purification, and separation, with the ability to use both porous and non-porous membranes. It is demonstrated that a membrane-based sustainable and green production can result in a high degree of process intensification, whereas the recovery and repurposing of catalysts and alcohol are anticipated to increase the process economics. Therefore, in this study sustainable biodiesel was synthesized from inedible seed oil (37 wt%) of Cordia myxa using a membrane reactor. Transesterification was catalyzed by heterogenous nano-catalyst of indium oxide prepared with leaf extract of Boerhavia diffusa. Highest biodiesel yield of 95 wt% was achieved at methanol to oil molar ratio of 7:1, catalyst load 0.8 wt%, temperature 82.5 °C and time 180 min In₂O₃ nanoparticles exhibited reusability up to five successive transesterification rounds. The production of methyl esters was confirmed using Fourier-transform infrared spectroscopy and Nuclear Magnetic Resonance. The predominant fatty acid methyl ester detected in the biodiesel was 5, 8-octadecenoic acid. Biodiesel fuel qualities were determined to be comparable to worldwide ASTM D-6571 and EN-14214 standards. Finally, it was concluded that membrane technology can result in a highly intensified reaction process while efficient recovery of both nano catalysts and methanol increases the economics of transesterification and lead to sustainable production.

Conversion of waste seed oil of Citrus aurantium into methyl ester via green and recyclable nanoparticles of zirconium oxide in the context of circular bioeconomy approach

In the current scenario of energy crises and depleting fossil fuels, there is need of sustainable and cheaper interventions with green technology to address these obstinate glitches. Biodiesel produced from waste, non-edible seed oils is a cleaner, green and alternate source of fuel for diesel engines which can possibly add to circular bioeconomy. In this study, Citrus aurantium a novel, nonedible and waste seed oil (38% w/w) producing feedstock was subjected to biodiesel synthesis using recyclable zirconium oxide nano particles synthesized with Alternanthera pungens aqueous leave extract. Maximum yield of 94% was obtained through optimized reaction parameters of methanol to oil molar ratio 6:1, reaction time 120 min, temperature 87.5 °C and catalyst loading of 0.5 wt% using Response Surface Methodology. Green nano particles of zirconium oxide were characterized via Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD) and Energy diffraction X-Ray (EDX) while; physiochemical characterization of synthesized biodiesel was carried through Fourier-transform infrared spectroscopy (FTIR), Gas Chromatography/Mass spectroscopy (GC/MS), and Nuclear magnetic resonance (NMR ¹H and ¹³C). Fuel properties of methyl ester met international standards of ASTM D-6571, EN 14214 and China GB/T 20828-2007. It was concluded that biodiesel production from Citrus aurantium waste and non-edible seed oil can be efficiently employed for generation of renewable energy which would further provide assistance in transformation of linear economy to circular bioeconomy.

Performance, Emission and Combustion Characteristics of a Diesel Engine Powered by Macadamia and Grapeseed Biodiesels

Biodiesel is an alternative, eco-friendly and renewable source of energy. It can be produced from a wide range of feedstocks which can be grown in marginal land use. It has drawn more attention to the researchers. In this study, the oil extraction, biodiesel conversion, and physiochemical properties of Macadamia (Macadamia integrifolia) and Grapeseed (Vitis vinifera) biodiesels are presented. The experimental investigation of diesel engine performance, emissions and combustion characteristics were conducted using B5 (5% biodiesel and 95% diesel by volume) and B10 (10% biodiesel and 90% diesel by volume) blends. The engine performance parameters, such as brake power (BP), brake specific fuel consumption (BSFC), and brake thermal efficiency (BTE) have been investigated in this experiment. The emission parameters, for example, carbon monoxide (CO), the ratio of CO2/CO, nitrogen oxide (NOx), hydrocarbon (HC), particulate matter (PM) have been measured during the experiment. Finally, the combustion parameters such as cylinder pressure (CP) were recorded, and heat release rate (HRR) was analysed and compared with that of diesel fuel. The study revealed that the Macadamia biodiesel performed better than Grapeseed biodiesel and behaved closely to that of diesel fuel. A significant reduction of engine emissions was found in the case of Macadamia biodiesel with a minimal reduction of engine performance. Further analysis of energy, exergy and tribological characteristics of the Macadamia biodiesel is recommended for assessing its feasibility for commercial application.

Potential of Chrozophora tinctoria Seed Oil as a Biodiesel Resource

Biodiesel is a renewable fuel that has been widely used in recent years. There are various resources used as biodiesel feedstocks, including animal fats, waste oils, and vegetable oils. In the present study, Chrozophora tinctoria seed oil is introduced as a new biodiesel feedstock. C. tinctoria is a weed and non-edible plant. So, the primary cost of this resource is very low, and hence it can be considered as a biodiesel source. This plant can also grow in most weather conditions. In the present study, the research team tried to produce biodiesel from C. tinctoria seeds through a transesterification reaction. To intensify the transesterification reaction, an ultrasonic device was used. In order to perform the transesterification reaction, potassium hydroxide was used as a catalyst. Important parameters, such as the reaction temperature, reaction time, molar ratio of methanol, and concentration of the catalyst, were adjusted. Based on the adjusted conditions, a biodiesel yield of 84% was attained. The properties of the C. tinctoria biodiesel was compared with the American Society for Testing and Materials (ASTM) standard. The results show the properties of a biodiesel: the density, kinematic viscosity, pour point, flash point, cloud point, and acid number are 0.868 g/cm3, 3.74 mPa, −7 °C, 169 °C, 4 °C, and 0.43 mg, respectively. The specification properties of C. tinctoria biodiesel can thus pass the requirement of the ASTM standard. So, C. tinctoria seed oil can be used as a suitable fuel source instead of petroleum-derived fuels.

The Cultivation of Lipid-Rich Microalgae Biomass as Anaerobic Digestate Valorization Technology—A Pilot-Scale Study

The aim of the study was to determine the use of digestate from anaerobic digestion of dairy wastewater as a culture medium for microalgae to obtain bio-oil. The experiments were conducted at a small scale in a closed raceway pond. The efficiency of the microalgae biomass production, the digestate treatment efficiency as well as the content and properties of the bio-oil obtained from the microalgal cells were analyzed. The produced biomass concentration was about 3000 ± 10.5 mg dry biomass/L, with an average growth rate of 160 ± 6.6 mgdm/L·d. The efficiency of organic compound and nutrient removal was above 90%. The bio-oil content in the biomass was about 20%. Based on the results of the study, a concept for technical-scale technology was developed.