Biodiesel synthesis from non-edible oils by transesterification using the activated carbon as heterogeneous catalyst

The need for renewable environmentally friendly energy resources is growing every day. Biodiesel is one of the most promising alternatives to the conventional non-renewable energy resources. Heterogeneous catalysts proved a high efficiency in the transesterification of oils to produce biodiesel. In this research, activated carbon was tested as a heterogeneous catalyst in the transesterification of two non-edible oils (waste cooking oil and Jatropha oil) with methanol to produce biodiesel. Activated carbon was characterized using X-ray diffraction, scanning electron microscope and Fourier transformed infrared. The effect of different operating parameters, namely operation time (30, 60, 120 and 180 min), alcohol-to-oil molar ratio (4:1, 6:1, 8:1 and 10:1), catalyst loading [0.5, 1, 2, 3 and 5% (w/w)] and rotational speed (100, 200, 300 and 400 rpm), was investigated. Results showed that increasing the operational time, the alcohol-to-oil molar ratio and the catalyst loading increases the conversion to biodiesel but only to some extent; increasing the stirring rate was found to be beneficial to the process. The optimum conditions were found to be 2 h of heating, 6:1 alcohol-to-oil ratio, 1 wt% catalyst loading and 400 rpm stirring. Under optimum conditions, the conversion to biodiesel reached 93.95 and 93.27% for the waste cooking oil and the Jatropha oil, respectively. The properties of the obtained biodiesel (density, viscosity, flash point, pour point and cloud point) were measured giving promising results.     

Different techniques for the production of biodiesel from waste vegetable oil

The production of biodiesel from waste vegetable oil offers a triple-facet solution: economic, environmental and waste management. The new process technologies developed during the last years made it possible to produce biodiesel from recycled frying oils comparable in quality to that of virgin vegetable oil biodiesel with an added attractive advantage of being lower in price. Thus, biodiesel produced from recycled frying oils has the same possibilities to be utilized. While transesterification is well-established and becoming increasingly important, there remains considerable inefficiencies in existing transesterification processes. There is an imperative need to improve the existing biodiesel production methods from both economic and environmental viewpoints and to investigate alternative and innovative production processes. This study highlights the main changes occurring in the oil during frying in order to identify the characteristics of oil after frying and the anticipated effects of the products formed in the frying process on biodiesel quality and attempts to review the different techniques used in the production of biodiesel from recycled oils, stressing the advantages and limitations of each technique and the optimization conditions for each process. The emerging technologies which can be utilized in this field are also investigated. The quality of biodiesel produced from waste vegetable oil in previous studies is also reviewed and the performance of engines fueled with this biodiesel and the characteristics of the exhaust emissions resulting from it are highlighted. The overarching goal is to stimulate further activities in the field.     

Development and evaluation of biodiesel fuel and by-products from jatropha oil

Biodiesel is an environmentally friend renewable diesel fuel alternative. Jatropha seeds can be a feedstock to produce a valuable amount of oil to be converted to biodiesel using transesterification reaction. Jatropha plant has been successfully grown in southern Egypt using primary treated municipal wastewater for its irrigation. Abench scale production of biodiesel from Jatropha oil (using methyl alcohol and sodium hydroxide as catalyst) was developed with methyl esters yield of 98 %. Biodiesel was produced on a pilot scale based on the bench scale experiment results with almost the same methyl esters yield of 98 %. The produced biodiesel was evaluated as a fuel and compared with petroleum diesel according to its physical and chemical parameters such as viscosity, flash point, pour point, cloud point, carbon residue, acid value and calorific value. The experimental techniques and product evaluation results show that such properties of the produced biodiesel are near to that of petroleum diesel. A mass balance representing the transesterification process is presented in this study. Glycerol of 85 % purity was produced and evaluated as a valuable byproduct of the process. Free fatty acids and sodium phosphate salts which have industrial interesting are also produced and evaluated.     

Biodiesel production from three mixes of oils with high free fatty content: quality evaluation and variable analysis

Due to the excessive use of fossil fuels around the world, more environmentally friendly alternatives have been studied. Technologies for the production of ethanol, biogas and biodiesel are focusing on the importance of improving costs and efficiency. Biodiesel can be used in automotive internal combustion, is biodegradable and has no presence of metals, however, it lacks competitiveness versus petrodiesel mainly by the high cost of the pure oils used for its production. The aim of this study was to obtain biodiesel from oil samples with high content of free fatty acids (>1 %) obtained from three fast food restaurants using their molecular weight and acidity index values in order to neutralize the free fatty acids in a one-step reaction and perform a screening for optimal conditions for transesterification. The experimental design consisted of two reaction times (60 and 90 min); four methanol–oil molar ratios—6:1, 10:1, 15:1 and 20:1; and two catalysts (NaOH and KOH) at three concentrations 0.5, 1 and 1.5 % with a constant temperature of 60 °C and 500 rpm. The optimum conditions for the different waste cooking oil feedstocks were established reaching a final yield up to 85.53 % of biodiesel, concluding that there is viability of production through the use of this raw material and free fatty acids neutralization technique, obtaining a biofuel that meets international quality standards.     

Production optimization and quality assessment of biodiesel from waste vegetable oil

Biodiesel production is worthy of continued study and optimization of production procedures because of its environmentally beneficial attributes and its renewable nature. In Egypt, millions L. of oil used for frying foods are discarded each year into sewage systems. Thus, it adds to the cost of treating effluent or pollutes waterways. This study is intended to consider aspects related to the feasibility of the production of biodiesel from waste/recycled oils in an attempt to help reduce the cost of biodiesel and reduce waste and pollution coming from waste oils. The variables affecting the yield and characteristics of the biodiesel produced from used frying oil were studied, the achieved results were analyzed and a set of recommendations was proposed. From the obtained results, the best yield percentage was obtained using a methanol/oil molar ratio of 6:1, potassium hydroxide as catalyst (1%) and 65 °C temperature for one hour. The yield percentage obtained from waste vegetable oil was comparable to that obtained from neat vegetable oil which reached 96.15% under optimum conditions. From the results it was clear that the produced biodiesel fuel, whether from neat vegetable oil or waste vegetable oil, was within the recommended standards of biodiesel fuel.     

Optimum reaction time, performance and exhaust emissions of biodiesel produced by microwave irradiation

While transesterification is well established, there remain considerable inefficiencies in existing transesterification processes. In this study an alternative energy stimulant, “microwave irradiation” was used for the production of the alternative energy source, biodiesel. The optimum parametric conditions obtained from the conventional technique were applied using microwave irradiation in order to compare both systems. The results showed that application of radio frequency microwave energy offers a fast, easy route to this valuable biofuel with advantages of enhancing the reaction rate and improving the separation process. The methodology allows for the use of high free fatty acid content feedstock, including used cooking oil; hence it helps to reduce the cost of production which constitutes a major hurdle towards widespread commercialization of biodiesel. The study also showed that the optimum reaction time for microwave-enhanced biodiesel production should be highly respected. Exceeding the optimum reaction time will lead to deterioration of both biodiesel yield and purity. This paper also reported the performance and exhaust emissions from a diesel engine when fuelled with a petroleum diesel fuel and two different biodiesel fuels; one obtained by the conventional technique and the other by microwave irradiation. It was concluded that microwave-enhanced biodiesel is not, at least, inferior to that produced by the conventional technique.     

Utilization of constructional lime as heterogeneous catalyst in biodiesel production from waste frying oil

Waste frying oil as valueless material which is disposed to environment can be used as a promising feedstock to produce biodiesel. In this study, constructional lime was used as alkaline heterogeneous catalyst for biodiesel production from virgin and waste frying oil. After determining the best activation temperature for the catalyst (600 °C), transesterification reactions were carried out at 65 °C, MeOH to oil molar ratio of 12:1, and 1 wt% of activated constructional lime under vigorous mixing for 5 h. Yield of reactions for virgin and waste frying oil (2.17 % free fatty acid) and pretreated waste frying oil (0.918 % free fatty acid) were 87, 93.9, and 94 %, respectively. Transesterification of virgin frying oil and pretreated waste frying oil were done at 65 °C, MeOH to oil molar ratio of 6:1, and 1 wt% of KOH as catalyst under vigorous mixing for 2 h, for comparison. Yield of the reaction was 98.6 and 95.1 %, respectively. Therefore, when constructional lime is used as catalyst pretreatment of waste oil is not necessary.     

Protection of biodiesel and oil from degradation by natural antioxidants of Egyptian Jatropha

Residue of methanolic extract of Egyptian Jatropha curcas contains bioactive substances such as phenolic compounds, which succeeded to be used as natural antioxidants for the protection of oils and their corresponding biodiesel against oxidative deterioration. In the present work, the residue of Jatropha roots were extracted with methanol and resulting residues, were investigated regarding their content of total phenolic compounds by folin-Cioalteau assay. Further, the antioxidant activities of the extracts were characterized by the 2,2-diphenyl-1-picrylhydrazyl radical method and proved remarkable results. Oxidation stability of Jatropha oil, used fried oil and olive oil and their corresponding biodiesel obtained by conventional transesterification were tested using thermal oxidation. Natural antioxidants such as (α-trocopherol), synthetic antioxidants as butylated hydroxytoluene and natural Jatropha root extract were used in the present study in comparison to investigate their addition effect on the oxidative stability of oils and their corresponding biodiesel. In the rapied thermal treatment test, results showed that addition of butylated hydroxytoluene 0.25 % was able to stabilize Jatropha oil 6 h, but poorly stabiliz biodiesel. Addition of 0.25 % α-trocopherol to Jatropha oil showed less oxidation stability after 2 h thermal treatment. Crude root extract addition at 0.25% to Jatropha oil showed good stability up to 4 h thermal treatment while addition of root extract at 0.25 % to biodiesel showed better stability up to 6 h thermal treatment. Besides addition of 220 ppm crude root extract to biodiesel was enough sufficient to occure oxidative stabilization. Also Jatropha root residue addition at 400 ppm was effective antioxidant for fresh Jatropha oil.     

The effect of hydrothermal impregnation of Ni,Co, and Cu on HZSM-5 in the nitrogen oxide removal

The selective catalytic reduction (SCR) of nitrogen oxides on M/ZSM-5 (M = Cu, Ni, Co) catalysts was investigated. The catalysts were prepared using hydrothermal impregnation of the metal chlorides and nitrates on ZSM-5. The catalysts were characterized by nitrogen absorption/desorption, X-ray diffraction, Fourier transform infrared (FTIR) spectroscopy, ultraviolet–visible diffusion reflection spectroscopy (UV–Vis DRS), temperature-programmed reduction (TPR), N₂O chemisorption and ammonia temperature-programmed desorption. The performance tests for SCR of NO were carried out in a fixed-bed reactor from 250 to 400 °C. During the impregnation, part of the aluminum was eliminated from the zeolite framework due to the acidity of the metal salt solution and heating process as indicated by the reduction in the intensity of XRD peaks and variations in the positions of the FTIR vibrational bands. The Cu(Cl)/ZSM-5 catalyst exhibited NO conversions over 90% over the entire temperature range. The other catalysts showed comparable activities, but the catalysts prepared with chloride salt precursors demonstrated higher activity than those based on nitrate as the precursor. Moreover, the TPR reduction peaks of the metal ion in catalysts prepared with chloride precursor were lower, and their UV–Vis absorption bands revealed bathochromic transfers with higher intensities. Concurrent with these changes, the activity of the catalyst increased. The TPR profiles indicated that Cu and Ni both had an oxidation number of +2, whereas Co was present in the oxidation number of +2 and +3. The mass transfer limitation analysis showed that for particles in millimeter size range or larger significant intra-particle mass transfer limitation would be expected.     

Effect of fuel molecules on properties and activity of KOH/calcium aluminate nanocatalyst for biodiesel production

New technologies such as microwaves have gained a large deal of attention from scientists and industries who sought increased rate of production processes. In this study, microwave irradiation was utilized to produce a novel KOH/Ca₁₂Al₁₄O₃₃ nanocatalyst used for biodiesel production. As support, calcium aluminate was prepared by microwave combustion method using different fuels including urea, glycine, sorbitol, and citric acid. The samples were then impregnated by KOH to improve their catalytic activities for microwave-enhanced transesterification of canola oil for biodiesel production. Results of XRD, BET, FTIR, TG, EDX, and FE-SEM analyses showed differences in physicochemical properties of the samples when using different fuels with different flame characteristics and combustion temperatures. Only the urea-fueled sample showed the crystalline structure of monocalcium aluminate (CaAl₂O₄), with the other samples exhibiting amorphous structure of CaO–Al₂O₃. However, all samples, except for that prepared by citric acid, transformed to crystalline structure of Ca₁₂Al₁₄O₃₃ by calcination during KOH impregnation. Among the samples, the KOH/Ca₁₂Al₁₄O₃₃ nanocatalyst prepared by sorbitol showed the highest activity in microwave-enhanced biodiesel production because of its large surface area, pore size, and basicity, converting 93.4% of canola oil to biodiesel at a methanol-to-oil molar ratio of 18, catalyst concentration of 4 wt%, and microwave output power of 450 W in 60 min of reaction time. Moreover, the sample showed well-distributed particle sizes without any agglomeration, so that it could easily maintain its level of activity for several rounds of use.     

Modification of thermal and oxidative properties of biodiesel produced from vegetable oils

Trans esterification of three vegetable oils, sunflower oil, linseed oil and mixed oils as; sunflower-soyabean and olein were carried out using methanol, and potasium hydroxide as catalyst. The methyl esters of the corresponding oils were separated from the crude glycerol and characterized by physical-chemical methods to evaluate their thermal properties. This methods are determination of densities, cloud points, pour points, flash points, kinematic viscosities, hydrogen/carbon ratios, sulfur contents, ash contents and triglycerides. The physico-chemical characteristic of biodiesel treated with ozone showed improvement of pour point and flash point indicating higher degree of safety for fuel. Methyl esters mixed with their corresponding ozonated oil were subjected to comparison and evaluation for their thermal properties by the thermo gravimetric analysis differential thermal analysis from which the calculated heat of enthalpy and comparison with the heat of conventional diesel. The results showed that the oxygen content of biodiesel samples treated with ozone increased weight % and resulted in more extensive chemical reaction, promoted combustion characteristics and less carbon residue was produced. Gas chromatography appeared more suitable to address the problem of determining/verifying biodiesel methyl ester and showed that methyl ester content was impurity free. Ultra violet-detection was used for rapid quantization of triglycerols. From the analyses performed biodiesel treated with ozone modified the thermal and oxidative stability shown by the high combustion efficiency indicated by the high heat of enthalpy and reducing the emission of particulate matter.     

Performance and environmental impact of a turbojet engine fueled by blends of biodiesels

Depletion of conventional fuels, concerns about environmental pollution and the tightening of exhaust emission legislations are the main reasons for increasing research on alternative fuels produced from agricultural feedstock. In this study, biodiesel fuels produced from cotton and corn vegetable oils are investigated as renewable fuels for a gas turbine engine for aviation. The biodiesel fuels are defined as cotton methyl ester (CTME) and corn methyl ester. The performance characteristics and exhaust emissions of the gas turbine engine are investigated when the engine fueled with three blends of 10%(B10), 20%(B20) and 50%(B50) of biodiesel/JetA-1 by volume. The biodiesel fuels were produced using transesterification process and characterized according to ASTM biodiesel specifications. Chemical and physical properties show a real potential of using biodiesel blends as an alternative for JetA-1. The measured engine performance parameters and exhaust emissions are compared with that of pure JetA-1 over a range of throttle setting. The gas turbine engine used in this study is equipped with pressure, flow, temperature, thrust and speed sensors that connected to data acquisition system and control unit in addition to exhaust gas analyzer. The experimental results show that biodiesel fuels can be used up to blend of 50% with JetA-1 in gas turbine engines with slight enhancement in engine performance and significant improvements in exhaust emissions. The engine static thrust is increased with 2% for B50 at lower and medium engine speeds and decreased with 11% at high engine speed compared to conventional JetA-1 fuel. The thrust-specific fuel consumption for biodiesel blends is lower than that for regular JetA-1 fuel. The gas turbine engine efficiency is increased for biodiesel blends by 14% compared to JetA-1, and this is reported for CTME B50. For oxygen concentration in exhaust gases emissions, the higher the biodiesel blend, the higher the O₂ concentration in the exhaust compared with JetA-1 fuel. The O₂ level increased by 6% for biodiesel blend of B50 compared to JetA-1 fuel. The emissions of CO and HC emissions decreased by 5 and 37%, respectively, compared with conventional JetA-1. Additionally, the biodiesel blends achieve a higher CO₂ and NO_x emissions with 11 and 27%, respectively, compared to JetA-1. The sulfur dioxide SO₂ decreased by 75% compared to the regular JetA-1 fuel.     

Effect of biodiesel on particulate numbers and composition emitted from turbocharged diesel engine

In present study a turbocharged, medium duty compression ignition engine was alternatively fuelled with biodiesel to investigate the changes in particulate matter composition, relative to that taken with diesel fuel. The engine was operated on an AC electrical dynamometer in accordance with an 8-mode, steady-state cycle. The numbers of particles were estimated through electrical low pressure impactor, while sulfates and trace metals were analyzed by ion chromatography and inductively coupled plasma-atomic emission spectroscopy, respectively. Nitric oxides and nitrogen dioxides were measured separately using SEMTECH-DS. Experimental results revealed that, on account of elevated ratios of nitrogen dioxide to nitrogen oxides, mean accumulation mode particles were 42 % lower with biodiesel. On the other hand, nuclei mode particles were higher with biodiesel, owing to heterogeneous nucleation and accounting for an increase in sulfate emissions up to 8 % with biodiesel as compared to diesel. On the average, trace metal emissions were significantly reduced showing 65–85.4 % reduction rates with biodiesel, relative to its counterpart. Further to this, individual congeners such as iron, calcium, and sodium were the predominant elements of the trace metals emitted from engine. The mean relative decrease in iron and calcium was 89–97.8 and 77.6–87 %, respectively, while the relative rise in sodium was in the range of 29–46 % with biodiesel. Further, elements such as zinc, chromium, and aluminum showed substantial abatement, whereas potassium, magnesium, and manganese exhibited irregular trends on account of variable engine loads and speeds during the various modes of cycle.     

A review of the synthesis and characterisation of pillared clays and related porous materials for cracking of vegetable oils to produce biofuels

This paper presents an overview of the modification of clay minerals by propping apart the clay layers with an inorganic complex. This expanded material is converted into a permanent two-dimensional structure, known as pillared clay or shortly PILC, by thermal treatment. The resulting material exhibits a two-dimensional porous structure with acidic properties comparable to that of zeolites. Synthetic as well as natural smectites serve as precursors for the synthesis of Al, Zr, Ti, Fe, Cr, Ga, V, Si and other pillared clays as well as mixed Fe/Al, Ga/Al, Si/Al, Zr/Al and other mixed metal pillared clays. Biofuels form an interesting renewable energy source, where these porous, catalytically active materials can play an important role in the conversion of vegetable oils, such as canola oil, into biodiesel. Transesterification of vegetable oil is currently the method of choice for conversion to biofuel. The second part of this review focuses on the catalysts and cracking reaction conditions used for the production of biofuel. A distinction has been made in three different vegetable oils as starting materials: canola oil, palm oil and sunflower oil.     

Microwave Induced Catalytic Oxidation of Methylene Blue in Water by ε-MnO_2

Microwave induced catalytic oxidation has been an important mean for treating high-concentration organic pollutants. Microwave catalyst is the key factor of the pollutants removal efficiency. Manganese oxides are excellent microwave absorbing materials which may play a potential role in treating organic pollutants by microwave induction. Manganese oxides are mainly constituted by [MnO6] octohedra connected to form framework or layered structures, and are usually classified into pyrolusite-ramsdellite family with (1×n) tunnel structure, hollandite-romanechite family with (2×n) tunnel structure, todorokite family with (3×n) tunnel structure and birnessite family with (1×∞) layered structure respectively. However, previous studies focused on the catalytic degradation efficiency or process conditions, lack of discussion on the related mechanism and few studies involved in the structural details of the catalysts.     

Correlation between the chemical structure of biodiesel and its physical properties

Biodiesel is a renewable, biodegradable, environmentally benign, energy efficient, substitution fuel which can fulfill energy security needs without sacrificing engine’s operational performance. Thus it provides a feasible solution to the twin crises of fossil fuel depletion and environmental degradation. The properties of the various individual fatty esters that comprise biodiesel determine the overall properties of the biodiesel fuel. In turn, the properties of the various fatty esters are determined by the structural features of the fatty acid and the alcohol moieties that comprise a fatty ester. Better understanding of the structure-physical property relationships in fatty acid esters is of particular importance when choosing vegetable oils that will give the desired biodiesel quality. By having accurate knowledge of the influence of the molecular structure on the properties determined, the composition of the oils and the alcohol used can both be selected to give the optimal performance. In this paper the relationship between the chemical structure and physical properties of vegetable oil esters is reviewed and engineering fatty acid profiles to optimize biodiesel fuel characteristics is highlighted.     

磁黄铁矿在纳米碳管生长中的作用

本文采用天然磁黄铁矿矿物－六方磁黄铁矿和单斜磁黄铁矿分别作催化剂,引入电弧法生长纳米碳管,发现二者具有截然不同的催化效果。在此基础上,探讨了在合成纳米碳管实验中磁黄铁矿的催化作用及催化机理。     

Utilization of waste coral for biodiesel production via transesterification of soybean oil

In the present study, the waste coral was utilized as a source of calcium oxide for transesterification of soybean oil into biodiesel (methyl esters). Characterization results revealed that the main component of the waste coral is calcium carbonate which transformed into calcium oxide when calcined above 700 °C. The Box–Behnken design of experiment was carried out, and the results were analyzed using response surface methodology. Calcination temperature, methanol– soybean oil molar ratio and catalyst concentration were chosen as variables. The methyl ester content (wt%) was response which must be maximized. A second-order model was obtained to predict methyl ester content as a function of these variables. Each variable was placed in the three low, medium and high levels (calcination temperature of 700, 800 and 900 °C; catalyst concentration of 3, 6 and 9 wt%; methanol-to-oil ratios of 12:1, 18:1 and 24:1). The optimum conditions from the experiment were found that the calcination temperature of 900 °C, catalyst concentration of 6 wt% and methanol-to-oil ratio of 12:1. Under these conditions, methyl ester content reached to 100 wt%. The waste catalyst was capable of being reused up to 4 times without much loss in the activity.     

Mineralogical controls on element dispersion in regolith over two mineralised shear zones near the Peak, Cobar, New South Wales

Effective exploration for polymetallic ore deposits in the Cobar region is hampered by incomplete knowledge of the mineralogical controls on element dispersion in the different regolith-landform settings throughout the area. A detailed mineralogical and geochemical study of regolith profiles over two major mineralised shear zones in a strongly weathered but dominantly erosional setting has delineated the important host minerals for a range of base metal cations. Iron oxides/oxyhydroxides, particularly goethite and to a much lesser extent hematite, are major hosts for Pb, Cu, and Zn as substituted/adsorbed cations and as constituents of associated or intergrown minerals, probably including members of the jarosite–alunite group. Correlations between elements and major regolith minerals suggest that goethite is also a host phase for As, Bi and Sb. Minor manganese minerals, including lithiophorite and cryptomelane group minerals, also host base metals in appreciable amounts. No clear association was found between gold and any particular secondary mineral. It is likely that gold is present largely as elemental gold particles associated with a range of minerals.Sampling strategies for geochemical exploration in variably leached and stripped regolith in the Cobar area should take into account the relative abundance of goethite and manganese oxides/oxyhydroxides within the profiles and overlying lag. Goethite would appear to be the preferred sampling medium for base metals. Highly ferruginous lag has a high proportion of hematite with variable maghemite and very low manganese oxide contents. Most of the base metal content in this surface material is strongly bound to the crystalline oxides/oxyhydroxides. More work is required to understand the effects of surface transformation of goethite to hematite and maghemite on the mobility and distribution of base metal cations in soil and ferruginous lags.     

The effect of emulsification on the selective agglomeration of fine coal

The coal beneficiation processes that extract coal particles using an agitated oil-water mixture may be generally termed selective agglomeration. One criticism of these processes has been that high energy inputs are needed to cause phase separation. Energy savings, however, may be obtained by the efficient emulsification of the oil phase (using say, a jet whistle emulsifier), prior to its addition to the raw coal pulp. In this work, the effect of prior emulsification on process parameters such as inversion time, product ash and recovery of organic material has been investigated for a number of different oils. Indications are that the inclusion of prior emulsification in the selective-agglomeration process will allow the exploitation of previously disregarded heavy oils. The use of these oils could bring substantial cost savings.