Degradation Of Biodiesel Research Articles

Oxidative stability and corrosivity of biodiesel produced from residual cooking oil exposed to copper and carbon steel under simulated storage conditions: Dual effect of antioxidants

This work investigates the oxidative stability and corrosivity of residual cooking oil (RCO) methyl biodiesel exposed to metallic coupons (copper and carbon steel) under simulated storage conditions (static immersion for 90 days within closed vessels) and the effect of antioxidants (tert-butylhydroquinone, curcumin, propylgallate, and butyl-hydroxyanisole) on biodiesel and metallic surfaces. The induction period measured during the experiment showed that all antioxidants retarded biodiesel degradation due to their antioxidant properties. Scanning-electron microscopy and X-ray diffraction of the metallic surfaces revealed the presence of oxides due to the corrosion by biodiesel in absence of antioxidants. Nevertheless, the presence of carbonaceous solids over the metallic surfaces was found which evidences the anticorrosive properties of the antioxidants, confirmed by X-Ray spectroscopy that showed increase in the content of carbon and oxygen on the surfaces. Measurements of corrosion rate also confirmed the anticorrosive action of all antioxidants. Hence, this work shows the dual properties of antioxidants acting as free radical scavengers in the RCO biodiesel as well as corrosive inhibitors, with a special performance of propylgallate, probably due to the presence of more hydroxyl groups in its structure that also may facilitate its interaction with the metallic surface.

Factors Influencing the Formation of Soft Particles in Biodiesel

<div class="section abstract"><div class="htmlview paragraph">In order to mitigate the effect of fossil fuels on global warming, biodiesel is used as drop in fuel. However, in the mixture of biodiesel and diesel, soft particles may form. These soft particles are organic compounds, which can originate from the production and degradation of biodiesel. Further when fuel is mixed with unwanted contaminants such as engine oil the amount soft particles can increase. The presence of these particles can cause malfunction in the fuel system of the engine, such as nozzle fouling, internal diesel injector deposits (IDID) or fuel filter plugging. Soft particles and the mechanism of their formation is curtail to understand in order to study and prevent their effects on the fuel system. This paper focuses on one type of soft particles, which are metal soaps. More precisely on the role of the short chain fatty acids (SCFA) during their formation. In order to do so, aged and unaged B10 was studied. The fuel matrixes were mixed with a calcium source such as calcium oxide (CaO), calcium carbonate (CaCO<sub>3</sub>) and engine oil. The importance of SCFA was studied by influencing the presence of the acids, by degrading the fuel, by the addition of formic acid and by inert gas bubbling. The created deposits and fuels mixtures were examined with the use of pH measurements, Fourier-transform infrared spectroscopy (FTIR), gas chromatography-mass spectrometry (GC-MS) and ion chromatography (IC). Opposed to the expectations, the results indicate that SFCA in not the most important factor for the formation of soft particles. It is shown that the calcium sources influenced the consistency and amount of the created soft particles. From the tested contaminants, CaO showed the highest yield towards precipitates. While degradation of the fuels showed to be the most important factor to form soap type soft particles.</div></div>

Analysis of the Application of Silica Gel and Iron Powder in Fuel Tank Storage to Reduce Biodiesel Degradation Rate

This study aims to determine the effect of using silica gel and iron powder to inhibit the degradation rate of biodiesel. The method used in this study was an experiment of biodiesel storage for 8 weeks. In this research, an acid number test and bacterial TPC test will be used as a parameter to measure the degradation rate of biodiesel. From this study, it is known that the use of silica gel and iron powder can reduce the rate of degradation of biodiesel and can reduce bacterial growth. This is evidenced by decreasing the degradation rate to 46% in the use of silica gel and iron powder with composition 3.2 g / l silica gel and 2.4 g / l iron powder. while in tank 7 (control) experienced the highest increase of up to 112%. In testing TPC bacteria it is known that in tank 2 which has decreased by 99.8%. while in tank 7 there was an increase in the number of bacteria by 37.6%.

Characterization and effect of Moringa Oleifera Lam. antioxidant additive on the storage stability of Jatropha biodiesel

The deterioration of biodiesel during its storage is promoted through oxidation, thus reducing its market value. The storage stability of Jatropha biodiesel produced through the transesterification process can be improved by Moringa Oleifera Lam. (MO) antioxidant addition. The powdered antioxidant was characterized through morphological study using Field Emission Scanning Electron Microscope (FESEM). The elemental analysis of the MO powder was examined using Energy Dispersive X-Ray Spectroscopy (EDS) and CHNS (Carbon, Hydrogen, Nitrogen, and Sulphur) analysis. The presence of antioxidant components like hydroxyl and phenol compounds has been confirmed through Fourier Transform Infrared Spectroscopy (FTIR) analysis. Thermal Analysis of the MO powder was carried out by employing Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA). The characterization of the MO antioxidant was carried out by studying the scavenging effect of free radicals and the presence of phenolic content responsible for it. The scavenging effect was analyzed by means of DPPH (1,1-diphenyl-2 picryl hydrazyl) assay and the total phenolic content in the antioxidant was determined by Folin-Ciocalteu method. The DPPH inhibition (%) was found to be 29.49, 43.72 and 54.59 at 500, 1000 and 1500 ppm respectively for the ethanol extracts of MO leaves. TPC for MO extract was found to be 112.3 GAE mg/g. The induction time measured using the Rancimat method was 2.29 h and 15.25 h for Jatropha biodiesel and its MO additive at 1500 ppm respectively. Results show that the addition of MO antioxidant has increased the storage stability of Jatropha biodiesel thus increasing its economic value. Importance of the studyThe significance of the study arises from the degradation of biodiesel in spite of oxidation due to environmental storage conditions. Novelty of the present study includes the improvement of the oxidation stability of biodiesel by means of Moringa Oleifera Lam. leaves. This natural antioxidant is widely available in tropical countries and it provides an increased economic value. The main objective of the study is to inhibit the oxidation of biodiesel by means of antioxidant addition and improve the storage stability.

Effect of the aging temperature on soybean biodiesel oxidation, quantifying the formed gums and sediments by thermogravimetry

Biodiesel has been widely used as an alternative fuel in diesel engines. However, although its physicochemical properties make it a substitute for traditional diesel fuel, biodiesel is more susceptible to oxidation and degradation during storage than diesel. The high content of unsaturated fatty acid methyl (or ethyl) esters in biodiesel causes its fast oxidative degradation when in contact with precursor agents as oxygen. These reaction products are highly unstable, resulting in a mixture of different species, some of them of high molecular weight, producing sediments and undesirable polymeric compounds. In this study, a sample of commercial soybean biodiesel (BS100) was aged at 50 °C, 110 °C, 150 °C and 200 °C in a Rancimat apparatus. This was performed bubbling air into the sample at 10 L h−1 flow rate for 5 h. The original biodiesel and the aged samples were analyzed by thermogravimetry (TG/DTG), in dynamic mode, under nitrogen atmosphere. Data were compared with those obtained from the analyses performed by size-exclusion chromatography (SEC). Fourier transform infrared spectroscopy (FTIR) analyses were also performed. The objective of this work was to evaluate the effect of the aging temperature on the oxidation of biodiesel and on the degraded product composition, as well as to quantify the formed gums and sediments. The thermogravimetric analysis shows that biodiesel samples aged at 150 °C and 200 °C have a higher content of heavier products (gum), 33.4% and 44.9%, respectively, than the non-aged biodiesel (2.8%). The SEC analysis indicates molecular weight value of 283, 1241 and 1380 g mol−1 for samples aged at 150 °C, 200 °C and for the non-aged sample, respectively, which confirms the results of the TG/DTG analysis. The widening of ester carbonyl stretching band (C=O, 1740 cm−1) in the FTIR spectra, as the aging temperature rises, confirms the degradation of biodiesel into acids, ketones and other compounds containing this functional group. The decrease in percentage transmittance in the region corresponding to the fingerprint (1500–500 cm−1) indicates that heavy products (gums and sediments) are produced. These results indicate that the degradation product content in the aged biodiesel is strongly dependent on the temperature of the aging process.

Metal Additives Influence in the Storing Stability Degradation of Biodiesel

Recently, biodiesel is used as an alternative fuel to reduce the air pollution. However, storage stability comes as it reduces the biodiesel properties after it been stored for a long period. This study was conducted to investigate the effect of storage duration on the stability degradation of biodiesel and the influence of metal additives nanoparticles blend to retard the deterioration of biodiesel. Biodiesel was synthesized using transesterification of waste cooking oil Gas Chromatography was performed to characterized the elements of biodiesel. Silver, manganese and iron nanoparticles were synthesized following sol-gel method. Nanoparticles were blended with biodiesel in concentration of 100 and 500 ppm using the ultrasonicator bath. Storage stability observation was performed according to ASTM4625 method which is 43 °C for one week. Gas Chromatography peaks shows similar components as standard biodiesel such as methyl palmitate, methyl stearate and methyl linoleate. Density and acid value were sis results proved that nanoparticles can help to retard the stability degradation of biodiesel.

Production, Perfomance and Emisions of Bio Diesel from Mixture of Animal Waste Fats and Degradation of Bio Diesel over Time

As the population increases day by day that makes the use of automobiles globally and hence the use of fuel increases especially diesel. Diesel fuel plays vital role due to immense working efficiency and less fuel consumption which increases the demand of diesel. As the crude oil going to be exhausted in few decades, so many researches are striving to find an alternate and finally found Bio-sources to manufacture Biodiesel whose properties are near to the Diesel fuel. These fuels are prepared from Crude oils. This paper deals with the production, performance and emissions of Biodiesel which is obtained after a chemical reaction called ‘Transesterfication’. It is a mixture of waste animal fats viz., fat from Pig called ‘Pork Lard’ and also fat from chicken called ‘Chicken Tallow’ are tested for different properties of the Biodiesel. The prepared bio diesel was tested in a Variable compression ratio diesel engine with different blend ratio of fuels (Bio diesel and normal diesel) and (bio diesel, diesel and ethanol) at different injection pressures. Also compared the performance of freshly blended biodiesel with degraded biodiesel for 2 years.

Application and analysis of rapid determination of oxidative degradation of biodiesel by surface tension and UV absorbance

In this paper, the accelerated degradation and oxidation of Jatropha biodiesel were carried out at 110 °C through the Rancimat method. The applicability of surface tension and UV absorbance in the fuel oxidation degree detection was studied through Gas Chromatography-Mass Spectrometer(GC-MS) and acid value titration. The analysis of experimental data demonstrated that the acid value, surface tension and density of Jatropha biodiesel increased by 551%, 3.8% and 0.91% following oxidation, respectively, while the UV absorption intensity at 230 nm increased nearly 2 times. Subsequently to oxidation, the correlations among surface tension, UV absorbance and acid value of Jatropha biodiesel were 0.9743 and 0.9702. Based on this fact, four prediction models for the degree prediction of fuel oxidation through surface tension and UV absorbance were proposed, while the cross-validation method was utilized. The test analysis finally determined that the two models were Logarithm model and Power model, while the RMESP and R values were 0.093, 0.9875, 0.0705 and 0.9928. Both the accuracy and correlation were high. The acid value prediction model based on surface tension was 7.8%, while the acid value prediction model based on UV absorbance was 3.8%. Both could accurately determine the oxidation degree of biodiesel.

Evaluation of the Oxidation Degradation Process of Biodiesel via 1H NMR Spectroscopy

Biodiesel is a suitable alternative to replace the petro-diesel. The biodiesel is formed by unsaturated esters easily degraded by interferences of oxygen, temperature, contact with metals or contaminants. The aim of this research was to investigate the biodiesel degradation process via 1H nuclear magnetic resonance (NMR) spectroscopy, observing the olefinic, bis-allylic and allylic protons signals of the chemical bonds, and by the induction period of the Rancimat. Biodiesel samples with metallic ions (Fe and Cu) and with rosemary natural extract were analyzed. The metal compounds showed a catalytic effect in the samples and the rosemary natural extract showed to be efficient by retarding the degradation process. The extract was ineffective in the presence of iron. Through the 1H NMR spectra was possible to observe changes in the signal intensities of the olefinic, bis-allylic and allylic protons as well as the formation of oxidation products in the biodiesel in the degradation process.

Avaliação do Comportamento dos Parâmetros Cinéticos da Reação de Oxidação do Biodiesel em Contato com Ligas Metálicas Durante o Armazenamento

Biodiesel has low oxidative stability due to the high content of unsaturated esters in its composition, and its degradation can occur due to exposure to air, humidity, light, heat, contaminants by microorganisms and in the presence of metals. This study aims to evaluate the influence of alloys of carbon steel, steel 1020 and sample of industrial pipe in biodiesel storage. The sample of biodiesel in contact with the pipe sample presented lower values of the induction period and, consequently, higher rate constants, accelerating biodiesel degradation. The biodiesel in contact with carbon steel and steel 1020 showed a lower degradation when compared to the industrial pipe sample. The biodiesel in the presence of the carbon steel alloy presented higher oxidative stability that of the sample in the presence of steel 1020. Some samples presented more complex oxidation reactions with deviations of the linearity described by Arrhenius.

Pea cultivar Blauwschokker for the phytostimulation of biodiesel degradation in agricultural soil

Phytoremediation is a cost-effective and ecologically friendly process that involves the use of plants to uptake, accumulate, translocate, stabilize, or degrade pollutants. The present study was conducted to demonstrate the potential of pea (Pisum sativum L. spp. sativum) cultivar Blauwschokker to phytostimulate biodiesel degradation in an agricultural soil, considering the influence of biological remediation on selected physiological parameters of plants and the amount and activity of soil microflora. Biodiesel was spiked into soil in dose of 50 g kg−1 of dry mass soil. The results of the study showed that the rate of biodiesel degradation in the vegetated soil was higher than that occurring by natural attenuation. At the same time, biodiesel showed a positive effect on the growth, development, and activity of soil bacteria and fungi. Moreover, the obtained results showed an improvement in physiological parameters of plants, including an increase in chlorophyll a and total chlorophyll content and higher relative water content in leaves in the presence of biodiesel.

Model Reactions Involving Ester Functional Groups during Thermo‐Oxidative Degradation of Biodiesel

AbstractBiodiesel is a renewable fuel used in diesel engines that is typically blended with diesel fuel. However, biodiesel is susceptible to oxidation, which has the potential to produce higher molecular weight materials that may adversely impact vehicle fuel‐system performance. To investigate the chemical reactions potentially important in biodiesel oxidation, four different types of chemical reactions involving esters were studied: (1) ester formation (reactions of acids with alcohols), (2) alcoholysis (reactions of alcohols with esters), (3) acidolysis (reaction of acids with esters), and (4) ester exchange (reactions between two esters). Experiments with representative model compounds were used to evaluate these reactions at 90 °C with aeration; conditions previously used to simulate thermo‐oxidative degradation during biodiesel aging. Reactions were monitored using gas chromatography, fourier transform infrared (FTIR) spectroscopy, and total acid number (TAN). Evidence is presented suggesting that alcoholysis and ester formation (Reactions 1 and 2), catalyzed by carboxylic acids, are important reactions of esters that could lead to larger molecules. Acidolysis (Reaction 3) proceeded at a comparatively slow rate and ester exchange reaction products (Reaction 4) were not detected under these aging conditions.

Plasticizing effect of oxidized biodiesel on polyethylene observed by nondestructive method

This paper explores the compatibility of biodiesel with different grades of polyethylene, specifically examining the extent of plasticization in order to gain a better understanding of the biofuel’s compatibility with this common polymer. Its bulk influences on polyethylene were investigated by gravimetric and mechanical testing, and by the application of a newly developed nondestructive ultrasonic testing method. Diffusion rates and the extent of plasticization by biodiesel were compared to results obtained with toluene, a known plasticizer for polyethylene. Mechanical and gravimetric analysis showed that biodiesel exhibited bulk attributes of a plasticizer for the tested polyethylenes with reduced moduli proportional to the amount of fuel uptake and that uptake was inversely proportional to crystalline content of the polymer. Based on uptake amounts, the efficiency of biodiesel as a plasticizer towards polyethylene was found to be more than double that of toluene. However, spectral analysis by ultrasonics showed that absorbed toluene and biodiesel influenced the microstructure of polyethylene differently. Notable differences in internal stresses were noted between the two fluids for the same amount absorbed. A subsequent study analyzed the impact that biodiesel degradation had on plasticization. Although the trend showed a slight change in diffusion rate with increasing oxidation of the medium, the mechanical and ultrasonic results did not show significant differences between fresh and degraded biodiesel within the 45 days span of the test. Combining the evidence observed in this study, a mechanism is proposed for biodiesel plasticization that can help with failure prevention and material selection.

Influence of stainless steel corrosion on biodiesel oxidative stability during storage

Biodiesel degradation is the modification of its original composition and properties as a result of fuel aging and metal corrosion during the storage process. This study examines the linkage between biodiesel degradation and the corrosion of stainless steel used to store the biodiesel. First, biodiesel was synthesized from soybean oil via methanolysis and ethanolysis homogeneous base-catalyzed transesterification routes. Next, immersion tests were carried out at room temperature, with little air turnover and in the dark. AISI 316 coupons were used to evaluate the corrosion of metal surfaces after contact with the biofuel. Changes in fuel composition were studied using FTIR and gas chromatography analysis, and the oxidative stability was analyzed by Rancimat and the peroxide index. The corrosion was evaluated by the gravimetric and SEM/EDS microscopy techniques and XRF analysis. Results revealed little influence of methyl and ethyl esters on metal degradation, indicating that routes have no importance on corrosion, since a low corrosion rate was observed for both esters, albeit with some surface micropitting. On the other hand, the presence of a small amount of metal ions released from the stainless steel surface during its corrosion promoted oxidation of the biodiesel, changing fuel composition and quality, as well as reducing its oxidative stability generally.

Analysis of the formation of radicals in biodiesel in contact with copper and metallic alloys via electronic paramagnetic resonance (EPR)

This research evaluated the formation of free radicals in the oxidative degradation of biodiesel in contact with metallic copper and metal alloys via EPR using the spin trapping PBN, identifying and quantifying the formation of free radicals in commercial biodiesel samples. The biodiesel samples were analyzed in contact with carbon steel, silver steel, metallic copper and blackberry extract. The lowest values of oxidative stability were obtained for biodiesel in contact with metallic copper, followed by carbon steel and silver steel. The highest values of radicals formed were obtained for the sample containing blackberry extract. It was possible to identify radical species such as OH and CHOHCH3 during the decomposition of biodiesel.

Molecular Modelling of Selected Combustion By-Products from the Thermal Degradation of Croton megalocarpus Biodiesel

Computational models are very important in understanding the nature of interactions in chemical systems from which important geometry parameters for various organic compounds can be extracted. This study explores computationally the geometry parameters of selected volatile organic compounds from the co-pyrolysis of Croton megalocarpus biodiesel blend using the Density functional theory (DFT) in conjunction with B3LYP correlation function at 6 - 31 G basis set. Gaussian ‘16 computational and Chemissian version 4.43 computational codes were used to generate electron density maps, band gap energies and frontier molecular orbitals. Frontier orbitals are central in estimating the reactive nature of a given molecular compound. The results indicated that the thermal degradation of selected molecular products from the co-pyrolysis of Croton megalocarpus biodiesel blends proceeds via high energy barriers between 400 and -1250 kJ/mol. Fundamentally the highest occupied and the lowest occupied molecular orbitals (MOs) are critical in determining the reactivity of a molecule. Moreover, the HOMO-LUMO band gap energies of 4-(2,4-dimethylcyclohexyl)-2-butanone, 3,4-dimethyl-3-cyclohexene-1-carbaldehyde, 5-(3-phenylpropanoyl)dihydro-2(3H)-furanone, and isopropenyl-4-methyl-1,2-cyclohexanediol were 0.674 eV, 3.918 eV, 3.393 eV, and 1.588 eV, respectively.

Biodiesel Induced Corrosion and Degradation: A Review

Biodiesel Induced Corrosion and Degradation: A Review

Effect of the natural antioxidant eugenol on quality preservation of commercial biodiesels produced with soybean oil or waste frying oil during storage at different temperatures

The objetive of this study was to evaluate the eugenol antioxidant efficiency on the oxidation stability of commercial biodiesel synthesized from soybean oil (SB) and wast fring oil (ORB) by determining induction period (IP) and acid number (AN) during storage at 10 °C or in accelerated oxidation test at 85 °C. For the oxidation stability evaluation, the Rancimat method (EN 14112) and AN (ASTM D664) analyses were used. The initial studies showed that the antioxidants eugenol and TBHQ when added separately increased IP values for the two types of biodiesel analyzed. During the storage at 10 °C, the IP was reduced for all samples. However, the lowest reduction percentages were for samples containing eugenol (-2.07 and -11.30% for SB and ORB, respectively). In relation to AN, the samples with the antioxidant eugenol led a greater decrease of this index, with the 10000 mg kg-1 concentration being the most efficient in the conservation of biodiesel. In the accelerated oxidation test in oven at 85 °C, pure BS presented higher susceptibility to degradation than the sample containing 10000 mg kg-1 of eugenol. In both storage studies, the eugenol natural antioxidant efficiency in the control of oxidative degradation of biodiesel becomes evident.

Evaluation of molecular spectroscopy for predicting oxidative degradation of biodiesel and vegetable oil: Correlation analysis between acid value and UV–Vis absorbance and fluorescence

The present study evaluated the applicability of UV–Vis absorption and fluorescence spectroscopy for monitoring oxidation level of oil extracted from white sesame seeds (Sesamum indicum L.) and its respective biodiesel degraded at 110 °C for various times. Correlations between spectroscopic data and acid value of the samples demonstrated that both optical techniques could be used to monitor the oxidative degradation. Additionally, a quantitative model to predict the acid value of oil and biodiesel using the UV–Vis absorption data was proposed. The prediction model was tested using a cross-validation (leave-one-out) analysis and demonstrated, for the first time, that the acid value of both biodiesel and vegetable oil can be predicted by applying the same protocol for UV–Vis spectra analysis. An average error of about 3 and 8% was achieved for the predicted acid value of the oil and biodiesel samples with respect to the measured acid values, respectively. Therefore, UV–Vis absorption technique could be applied to quantitatively monitor the oxidative degradation of vegetable oil and biodiesel in a rapid and practical way.

Simulation of a surface spill of different diesel/biodiesel mixtures in an ultisol, using natural attenuation and bioaugmentation/biostimulation.

Accidents caused by leaks and/or spills on soils need to be addressed. Natural attenuation, biostimulation and bioaugmentation can be useful bioremediation strategies for decontamination processes in soils of diesel/biodiesel mixtures. The purpose of this study was to evaluate the degradation rate of the different fuels (B0, B20 and B100) in an ultisol under natural attenuation and biostimulation/bioaugmentation during 60 days of incubation in a controlled microcosm simulating a surface spill over soil. The degradation of different diesel/biodiesel mixtures was monitored for up to 60 days by dehydrogenase activity, respirometry by CO2 release, the most probable number of heterotrophic and degrading microorganism and gas chromatography. The bacterial inoculum employed for biostimulation/bioaugmentation strategy consisted of Bacillus megaterium, Bacillus pumilus, Pseudomonas aeruginosa, and Stenotrophomonas maltophilia. The two bioremediation strategies have showed great degradation rates. The natural attenuation was effective for B0 and B20 treatments. The addition of the bacterial consortium and macronutrients contributed to the increased degradation of pure biodiesel in relation to natural attenuation, with higher rates for CO2 release, enzymatic and degrading activity. It is suggested that the bacterial consortium has proven effective for presenting significant values for such parameters until the end of the 60-day incubation period.