Crude Vegetable Oils Research Articles

Comparative studies on performance evaluation of DI diesel engine with high grade low heat rejection combustion chamber with carbureted alcohols and crude jatropha oil

Abstract Search for renewable fuels such as vegetable oils and alcohols (ethanol and methanol) has become pertinent in the context of fossil fuel crisis and vehicle population explosion. The drawbacks associated with vegetable oils (high viscosity and low volatility) and alcohols (low cetane number) for use in diesel engines call for a hot combustion chamber, with its significant characteristics of higher operating temperature, maximum heat release, higher brake thermal efficiency and ability to handle the lower calorific value fuel. Investigations were carried out to evaluate the performance of a direct injection compression ignition engine with high grade low heat rejection (LHR) combustion chamber consisting of air gap insulated piston with 3 mm air gap with superni (an alloy of nickel) crown, air gap insulated liner with superni insert and ceramic coated cylinder head fueled with crude jatropha oil and carbureted alcohol (ethanol/methanol) with varied injection timings and injector opening pressures. Carbureted alcohol was inducted into the engine through a variable jet carburetor, installed at the inlet manifold of the engine at different percentages of crude vegetable oil at full load operation on mass basis. Comparative studies were made with engine with LHR combustion chamber with data of conventional engine with test fuels of diesel, crude vegetable oil and carbureted alcohol at recommended injection timing and optimized injection timing. Comparative studies were also made with methanol operation with data of ethanol operation on both versions of the combustion chamber with different operating conditions. Performance parameters, exhaust emissions and combustion characteristics were determined at full load operation of the engine with varied injection timings and injector opening pressures. Aldehydes were measured by the dinitrophenyl hydrazine (DNPH) method. Combustion diagnosis was carried out with a miniature piezoelectric pressure transducer, top dead center (TDC) encoder and special pressure–crank angle software package. The optimum injection timing was observed to be 32° bTDC with conventional engine while it was 29° bTDC for insulated engine with vegetable oil operation. The maximum induction of alcohol (methanol/ethanol) in conventional engine was found to be 35%, while it was 60% for the engine with LHR combustion chamber at recommended injection timing (27° bTDC). However, the maximum induction of alcohol was observed to be 55% with engine with LHR combustion chamber at its optimum injection timing. With maximum induction of methanol, at an injector opening pressure of 190 bar, engine with LHR combustion chamber at its optimum injection timing increased peak brake thermal efficiency by 3%; at full load operation brake specific energy consumption comparable, decreased exhaust gas temperature by 3%, decreased coolant load by 6%, volumetric efficiency comparable, increased formaldehyde levels by 30%, decreased acetaldehyde levels by 35%, decreased particulate emissions by 20%, decreased nitrogen oxide levels by 14%, increased peak pressures by 3% and maximum rate of pressure rose by 3%, when compared with ethanol operation on engine with LHR combustion chamber at its optimum injection timing.

Performance evaluation of medium grade low heat rejection diesel engine with carbureted methanol and crude jatropha oil

Abstract Vegetable oils and alcohols (ethanol and methanol) are important substitutes for diesel fuel as they are renewable in nature. However drawbacks associated with vegetable oils (high viscosity and low volatility) and alcohols (low cetane number) call for engine with hot combustion chamber with its significant characteristics of higher operating temperature, maximum heat release, higher brake thermal efficiency (BTE) and ability to handle the lower calorific value fuel. Methanol was inducted into the engine through a variable jet carburetor, installed at the inlet manifold of the engine at different percentages of crude vegetable oil at full load operation on mass basis. Crude vegetable oil was injected at near end of compression stroke. Performance was evaluated with engine with LHR combustion chamber consisting of air gap (3mm) insulated piston with superni (an alloy of nickel) crown and air gap insulated liner with superni insert with mixture of carbureted methanol and crude vegetable oil with varied injector opening pressure and injection timing. Comparative studies were made with crude vegetable oil operation on engine with LHR combustion chamber at similar operating conditions. Performance parameters and exhaust emissions were determined at various values of brake mean effective pressure. Aldehydes were measured by the 2,4, dinitrophenyl hydrazine (DNPH) method. Combustion characteristics were measured with top dead center (TDC) encoder, pressure transducer, console and special pressure–crank angle software package at full load operation of the engine. The optimum injection timing with crude vegetable oil operation on LHR combustion chamber was 29° bTDC. The maximum induction of methanol was 55% at recommended injection timing (27° bTDC), while it was 50% at optimum injection timing. With maximum induction of methanol, at an injector opening pressure of 190 bar, at recommended injection timing, engine with LHR combustion chamber increased peak brake thermal efficiency by 6%; at full load operation it decreased brake specific energy consumption by 2%, exhaust gas temperature by 16%, coolant load by 11%, volumetric efficiency by 6%, sound levels by 8%, particulate matter by 45%, NOx emissions by 46%, increased formaldehyde emissions and acetaldehyde emissions drastically, increased peak pressure by 23% and maximum rate of pressure rise by 17% when compared with crude jatropha oil operation at similar operating conditions.

Exploration on the effect of phospholipids on free lipase-mediated biodiesel production

• Free lipase NS81006 was used for biodiesel production from oil with phospholipids. • More than 5% phospholipids had negative influence on NS81006-mediated biodiesel production. • Either phospholipids or methanol alone did not have adverse effect on free lipase. • It showed that the coexistence of phospholipids and methanol resulted in inhibitory effect on lipase's catalytic performance during methanolysis for biodiesel production. Free lipase-mediated biodiesel production has been drawing great attention for its lower cost and faster reaction rate compared to immobilized lipase. Since biodiesel derived from vegetable oils may cause competition with food supply, the exploration of crude vegetable oils as well as microbial oils as the feedstock has aroused great interest worldwide. It is reported that those crude oils usually contain some amount of phospholipids, typically with content varying from 2% to 10%. Our previous study showed that phospholipids content within 2% in the oil feedstock was even beneficial to free lipase NS81006-catalyzed biodiesel production. However, there was no research about the influence of much higher phospholipids content on free lipase-mediated methanolysis for biodiesel production. In this paper, the effect of varied content of phospholipids on free lipase NS81006-mediated biodiesel production as well as the related mechanism was investigated for the first time. It was found that both the catalytic performance and reuse stability of free lipase NS81006 were inhibited with more than 5% phospholipids contained in the oil feedstock. Exploration on the related influence mechanism revealed that either phospholipids or methanol (with appropriate addition strategy) alone did not have negative effect on the catalytic performance of the lipase, while the coexistence of phospholipids and methanol in the system led to significant inhibitory effect on the lipase. The further exploration indicated that with the increase of phospholipids content, the amount of solubilized methanol gradually increased in the micelle, which may subsequently result in negative effect on the enzyme's catalytic performance.

Dry Degumming of Corn-oil for Biodiesel Using a Tubular Ceramic Membrane

Gum removal from vegetable oils applied for diesel fuel is an essential process, since the presence of gum in direct use to the diesel engine might cause plugging in the engine filters, lines and injectors. In the biodiesel production, the use of crude vegetable oils without degumming might decrease conversion rate and hard to separate glycerol from biodiesel, during and after trans-esterification reaction respectively. Ultrafiltration is potential technology for degumming of crude vegetable oils, however since the oil constituents have nearly close molecular weight, the membrane degumming process is a difficult process. In order to understand the membrane degumming process in corn-oil, both experimental and computational works have been conducted. Dry degumming process of corn-oil has been carried out using a tubular ceramic membrane, and the effects of process conditions (temperature, trans-membrane pressure, cross flow velocity) and concentration polarization were investigated. Computational fluid dynamics simulation based on Galerkin finite element methods (FEM) has been carried out and used to predict the retention layer occurred during inside-out operation of membrane degumming. The numerical results show that the increasing of crossflow velocity lead to increase axial Reynolds number, and on the other hand decrease the thickness of the retention layer. In the x/R=1.0 position, the retention layer thicknesses were δp= 4.0x10-4 m and δp= 1.7x10-4 m, for Re=1000 and Re=10000, respectively. Moreover, the effect of increasing Schmidt number gives a significant retention layer thickness decline, i.e. from δp= 4.8x10-4 m to δp= 2.2x10-4 m, by using Sc=4x105 to Sc=1.3x106, respectively. The Schmidt numbers depends on the diffusion behavior of solute in the solvent, and has been concluded that wet-degumming process was a better method to prevent higher concentration polarization close to the membrane wall.

Evaluation of methodologies to determine vegetable oil species present in oil mixtures: Proposition of an approach to meet the EU legislation demands for correct vegetable oils labelling

Refined vegetable oils are widely used in the food industry as ingredients or components in many processed food products in the form of oil blends. To date, the generic term ‘vegetable oil’ has been used in the labelling of food containing oil blends. With the introduction of new EU Regulation for Food Information (1169/2011) due to take effect in 2014, the oil species used must be clearly identified on the package and there is a need for development of fit for purpose methodology for industry and regulators alike to verify the oil species present in a product. The available methodologies that may be employed to authenticate the botanical origin of a vegetable oil admixture were reviewed and evaluated. The majority of the sources however, described techniques applied to crude vegetable oils such as olive oil due to the lack of refined vegetable oil focused studies. Nevertheless, DNA based typing methods and stable isotopes procedures were found not suitable for this particular purpose due to several issues. Only a small number of specific chromatographic and spectroscopic fingerprinting methods in either targeted or untargeted mode were found to be applicable in potentially providing a solution to this complex authenticity problem. Applied as a single method in isolation, these techniques would be able to give limited information on the oils identity as signals obtained for various oil types may well be overlapping. Therefore, more complex and combined approaches are likely to be needed to identify the oil species present in oil blends employing a stepwise approach in combination with advanced chemometrics. Options to provide such a methodology are outlined in the current study.

Production of palm and jatropha based biodiesel and investigation of palm-jatropha combined blend properties, performance, exhaust emission and noise in an unmodified diesel engine

An ever increasing drift of energy consumption, unequal geographical distribution of natural wealth and the quest for low carbon fuel for a cleaner environment are sparking off the production and use of biodiesels in many countries around the globe. In this work, palm biodiesel and jatropha biodiesel were produced from the respective crude vegetable oils through transesterification, and the different physicochemical properties of the produced biodiesels have been presented, and found to be acceptable according to the ASTM standard of biodiesel specification. This paper presents experimental results of the research carried out to evaluate the BSFC, engine power, exhaust and noise emission characteristics of a combined palm and jatropha blend in a single-cylinder diesel engine at different engine speeds ranging from 1400 to 2200 rpm. Though the PBJB5 and PBJB10 biodiesels showed a slightly higher BSFC than diesel fuel, all the measured emission parameters and noise emission were significantly reduced, except for NO emission. CO emissions for PBJB5 and PBJB10 were 9.53% and 20.49% lower than for diesel fuel. By contrast, HC emissions for PBJB5 and PBJB10 were 3.69% and 7.81% lower than for diesel fuel. The sound levels produced by PBJB5 and PBJB10 were also reduced by 2.5% and 5% compared with diesel fuel due to their lubricity and damping characteristics.

Recovery of different waste vegetable oils for biodiesel production: A pilot experience in Bahia State, Brazil

In Brazil, and mainly in the State of Bahia, crude vegetable oils are widely used in the preparation of food. Street stalls, restaurants and canteens make a great use of palm oil and soybean oil. There is also some use of castor oil, which is widely cultivated in the Sertão Region (within the State of Bahia), and widely applied in industry. This massive use in food preparation leads to a huge amount of waste oil of different types, which needs either to be properly disposed of, or recovered. At the Laboratorio Energia e Gas-LEN (Energy & Gas lab.) of the Universidade Federal da Bahia, a cycle of experiments were carried out to evaluate the recovery of waste oils for biodiesel production. The experiences were carried out on a laboratory scale and, in a semi-industrial pilot plant using waste oils of different qualities. In the transesterification process, applied waste vegetable oils were reacted with methanol with the support of a basic catalyst, such as NaOH or KOH. The conversion rate settled at between 81% and 85% (in weight). The most suitable molar ratio of waste oils to alcohol was 1:6, and the amount of catalyst required was 0.5% (of the weight of the incoming oil), in the case of NaOH, and 1%, in case of KOH.The quality of the biodiesel produced was tested to determine the final product quality. The parameters analyzed were the acid value, kinematic viscosity, monoglycerides, diglycerides, triglycerides, free glycerine, total glycerine, clearness; the conversion yield of the process was also evaluated.

Comparative analysis of biodiesel versus green diesel

The use of biofuels is becoming more and more common because of both environmental and economical concerns. Several attempts have been made for the substitution of fossil fuels with other alternative fuels. An important feedstock for the production of biofuels fully adapted to modern engine technology is ester molecules derived from refined or crude vegetable oils and animal fats. Two distinct techniques have been applied for the transformation of the vegetable oil's esters into molecules compatible with petroleum diesel that is transesterification of ester molecules for the production of lighter esters by using an alcohol and hydrogenation of ester bonds for the production of linear hydrocarbons. The way both biofuels are produced is discussed in this work. Raw materials tested, production methods and systems investigated, feasibility of production of these fuels in plant and industrial scale and the main characteristics of the two fuels are included. WIREs Energy Environ 2014, 3:3–23. doi: 10.1002/wene.78This article is categorized under: Bioenergy > Science and Materials Energy and Development > Science and Materials

Pro‐ and Antioxidative Effect of α‐Tocopherol on Edible Oils, Triglycerides and Fatty Acids

Using advanced electron paramagnetic resonance techniques (EPR), oxidation of crude vegetable oils and their components (fatty acids and triglycerides) by radicals generated from hydrogen peroxide was investigated. The correlation rotational times were determined allowing us to characterize radicals formed during edible oils oxidation. Additionally 1H- and 14N-hyperfine coupling constants differentiate the fatty acids dependently on their unsaturation. The acids with a higher number of unsaturated bonds exhibit higher AN values of PBN/·lipid adduct. The waste oil with high free fatty acids content underwent the oxidation reaction more efficiently, however due to saturation and the high content of the fatty acids the carbon-centered radicals formed (upon hydrogen peroxide radicals) and their PBN (N-tert-butyl-α-phenylnitrone) adducts were less stable. The antioxidant effect was dependent on the amount of α-tocopherol added. In small amounts of up to 0.35 mg/1 g of fatty acid or triglyceride, it inhibited the creation of PBN/·lipid adducts while with higher amounts it intensified adduct formation. The α-tocopherol (AT) addition influence was also studied as spin scavenging dependence and indicated that any addition of the antioxidant in the investigated samples led to free radical scavenging and the effect increased with the increase in AT content.

Effect of phospholipids on free lipase-mediated methanolysis for biodiesel production

Free lipase-mediated alcoholysis offers an effective alternative approach to biodiesel production due to its merits of faster reaction rate and lower preparation cost. Further promoting the application of free lipase in catalyzing the transesterification of crude renewable oils is of significance since the cost of oil feedstock accounts for a major part in biodiesel production. Crude renewable oils typically contain a certain amount of phospholipids and it has been found that the phospholipids have inhibitory effect on lipase's catalytic performance during immobilized lipase-catalyzed biodiesel production. However, the influence of phospholipids on free lipase-mediated alcoholysis in oil/water biphasic system has not been reported. In this work, free lipase from Aspergillus niger was employed as the catalyst for biodiesel production and the effect of phospholipids on free lipase's catalytic performance was explored for the first time. It was found that both the reaction rate and the final FAME content increased and the free lipase exhibited better reuse stability in the presence of phospholipids. Further study on the distribution of phosphorous showed that within 2% phospholipids contained in the oil feedstock, only less than 4 ppm phosphorous remained in the final methyl esters, which well met the phosphorous demand of biodiesel standard. The above results demonstrated that free lipase-mediated alcoholysis was promising for biodiesel production especially with low quality crude vegetable oils as the feedstock.

Analysis and simulation of an industrial vegetable oil refining process

This work focuses on the performance analysis of an industrial vegetable oil refinery. Using a commercial process simulator, a process model was developed and validated against actual vegetable oil refinery field data. The simulator allowed investigating both energy and safety aspects related to the presence of residual extraction solvent (extraction grade hexane) in the processed crude vegetable oil. The critical nodes for hexane accumulation in the process were evaluated, both considering ordinary operative conditions and undesired process deviations due to increase of the hexane content. In this latter case, the control actions able to restore the normal operation were simulated, in terms of increased utility consumption (e.g., motive steam for ejectors and cooling water) or by modifying and optimizing equipment operating conditions. Finally, the possibility of flammable mixtures formation inside process vent pipes, caused by the entrainment of air due strong vacuum conditions, was also investigated.

Life cycle assessment of soybeans production and processing system into soy oil using solvent extraction process

Agricultural operations have been indicated to be some of the major emitters of greenhouse gases (GHG), particularly methane (CH4) and nitrous oxide (N2O) around the globe, and it is important to determine the quantity emitted and how they can be reduced. The environmental impacts associated with field production and industrial processing of soybean into crude vegetable oil in Nigeria was therefore studied using the life cycle impacts assessment tool. The emission from the various inputs into the system was aggregated into a large inventory table. The functional unit was defined as one kilogram of soybean. The environmental impact categories used in this study are global warming, acidification, eutrophication and ozone layer depletion. Of these four environmental impacts, global warming has the highest impact score of 4.7516E-01 kg CO2 equivalent, followed by eutrophication (1.6414E-04 kg NO3 equivalent). Ozone layer depletion has the lowest environmental impact score of –2.8207E-07 kg R11 equivalent. The high impact score of global warming is due to the high emission of CO2 gas from fossil fuel and biomass combustion during field operations and processing of soybeans.

Evaluating and Comparing of a Diesel Engine Performance and Its Pollutants Operating on Blends of Sunflower and Soybean Biodiesel Fuel

This study eventuated in two stages, the first is to extract biodiesel fuel from crude vegetable oil of sunflower and soybean oils, and the second stage is to use these extracted fuels to operate diesel engine. Three types of fuel used, the first fuel is conventional diesel fuels for comparison, the second and third types of fuel consist of four blends (B25, B50, B75, B100) for each type of sunflower and soybean biodiesel fuels. The fuels were used in the engine to find the criteria of performance of the engine which includes(Torque, Brake power, Specific fuel consumption) and discovers in the combustion products on (O2, CO, NO, CO2) for each type of fuel. The result of this study shows that the maximum performance of the engine is reached when the conventional diesel fuel is used, but increased the pollutants in atmosphere. The use of biodiesel fuel in the engine decreases the performance of the engine, but it will decrease emitting of (CO2, CO) and increase(NO) comparing with conventional diesel fuel. The results show decrease 31.9% in engine power when use the fuel (B100-SF) and decrease 18.2% of CO2 comparing with conventional diesel fuel. The fuel(B100-SB) shows decrease 33.7% in engine power and decrease 38.6% of CO2 when comparing with conventional diesel fuel. In addition the blends (B25-SF, B50-SF, B75-SF) give better engine performance and less pollutants emission when comparing with identical blends of fuel (B25-SB, B50-SB, B75-SB).

Evaluating and Comparing of a Diesel Engine Performance and Its Pollutants Operating on Blends of Sunflower and Soybean Biodiesel Fuel

This study eventuated in two stages, the first is to extract biodiesel fuel from crude vegetable oil of sunflower and soybean oils, and the second stage is to use these extracted fuels to operate diesel engine. Three types of fuel used, the first fuel is conventional diesel fuels for comparison, the second and third types of fuel consist of four blends (B25, B50, B75, B100) for each type of sunflower and soybean biodiesel fuels. The fuels were used in the engine to find the criteria of performance of the engine which includes(Torque, Brake power, Specific fuel consumption) and discovers in the combustion products on (O2, CO, NO, CO2) for each type of fuel. The result of this study shows that the maximum performance of the engine is reached when the conventional diesel fuel is used, but increased the pollutants in atmosphere. The use of biodiesel fuel in the engine decreases the performance of the engine, but it will decrease emitting of (CO2, CO) and increase(NO) comparing with conventional diesel fuel. The results show decrease 31.9% in engine power when use the fuel (B100-SF) and decrease 18.2% of CO2 comparing with conventional diesel fuel. The fuel(B100-SB) shows decrease 33.7% in engine power and decrease 38.6% of CO2 when comparing with conventional diesel fuel. In addition the blends (B25-SF, B50-SF, B75-SF) give better engine performance and less pollutants emission when comparing with identical blends of fuel (B25-SB, B50-SB, B75-SB

Potential of Jatropha curcas as a Biofuel, Animal Feed and Health Products

AbstractJatropha curcas is a multipurpose plant with numerous attributes. It can potentially become one of the world's key energy crops. Its seed weighs 0.53–0.86 g and the seed kernel contains 22–27% protein and 57–63% lipid indicating good nutritional value. The seeds can produce crude vegetable oil that can be transformed into high quality biodiesel. Several methods for oil extraction have been developed. In all processes, about 75% of the weight of the seed remains as a press cake containing mainly carbohydrates, protein and residual oil and is a potential source of livestock feed. The highly toxic nature of whole as well as dehulled seed meal due to the presence of high levels of shells, toxic phorbol esters and other antinutrients prevents its use in animal diet. The genetic variation among accessions from different regions of the world and rich diversity among Mexican genotypes in terms of phorbol ester content and distinct molecular profiles indicates the potential for improvement of germplasm of Jatropha through breeding programs. The extracts of Jatropha display potent cytotoxic, antitumor, anti‐inflammatory and antimicrobial activities. The possibilities on the exploitation potential of this plant through various applications have been explored.

Immobilization of Phospholipase A1 and its Application in Soybean Oil Degumming

AbstractPhospholipase A1 (PLA1), or Lecitase® Ultra, was immobilized on three different supports, calcium alginate (CA), calcium alginate‐chitosan (CAC), and calcium alginate‐gelatin (CAG), and crosslinked with glutaraldehyde. The results indicated that PLA1–CA retained 56.2% of the enzyme's initial activity, whereas PLA1–CAC and PLA1–CAG retained 65.5 and 60.2%, respectively. Compared with free PLA1, the optimal pH of immobilized PLA1 shifted to the basic side by 0.5–1.0 pH units and the pH/activity profile range was considerably broadened. Similarly, the temperature‐optima of PLA1–CAC and PLA1–CAG increased from 50 to 60 °C, and their thermal stability increased with relative activities of more than 90% that covered a wider temperature range spanning 50–65 °C. In a batch oil degumming process, the final residual phosphorus content was reduced to less than 10 mg/kg with free PLA1, PLA1–CAC and PLA1–CA in less than 5, 6 and 8 h respectively while PLA1–CAG was only able to reduce it to 15 mg/kg in 10 h. When the PLA1–CAC was applied in a plant degumming trial, the final residual phosphorus content was reduced to 9.7 mg/kg with 99.1% recovery of soybean oil. The recoveries of immobilized PLA1–CAC and activity of PLA1 were 80.2 and 78.2% respectively. Therefore, it was concluded that PLA1–CAC was the best immobilized enzyme complex for the continuous hydrolysis of phospholipids in crude vegetable oils.

Characteristics of a tractor engine using mineral and biodiesel fuels blended with rapeseed oil

One of the most unfavourable characteristics of crude vegetable oil when used as the fuel is the high viscosity. To improve this weakness, oil can be blended with mineral diesel or biodiesel fuels. This study was designed to evaluate how the use of mineral diesel or biodiesel blend with cold pressed rapeseed (Brassica napus) oil affects the engine power, torque and fuel consumption. A tractor equipped with direct injection, water cooling system and three-cylinder diesel engine was used for the experiment. Fuels used were standard diesel fuel (diesel), rapeseed oil methyl ester - biodiesel (B100) and their mixtures with 10, 30 and 50 vol. % of cold pressed rapeseed oil (RO). Increased portion of RO in diesel fuel blends had almost no effect on the torque measured on the tractor PTO shaft; it however decreased the maximal power. Fuel blends with B100 and rising RO content (up to 50%) gave a positive correlation with maximal torque and power. By increasing the portion of RO from 0 to 50%, the minimal specific fuel consumption increased by 6.65% with diesel and decreased by 2.98% with B100 based fuel.

Croton megalocarpus (Musine) seeds as a potential source of bio-diesel

This work provides details of an activity undertaken to determine the relevant properties of Croton megalocarpus seeds as a source of vegetable oil and its prospects as a non-food crop source of biodiesel. C. megalocarpus is a tree indigenous to East Africa which grows up to a height of 35–40 m and produces seeds which contain 40–45% oil on a mass basis. The seeds were examined and properties determined that relate to their transport and storage/handling characteristics. Oil was extracted mechanically from the seeds using a hydraulic press and chemically from the pressing residue using petroleum ether. The combustion quality of the extracted crude vegetable oil such as the gross calorific value, carbon, hydrogen and oxygen content and ash content were then determined. This study indicates that the oil from the C. megalocarpus tree has a strong potential as a source of biodiesel.

Vegetable Oil Deacidification by Amberlyst: Study of the Catalyst Lifetime and a Suitable Reactor Configuration

Deacidification of crude vegetable oils containing high amounts of free fatty acids is the first step toward low-cost biodiesel production. In order to lower the acid content, the most popular method is based on an esterification process carried out with methanol and using Amberlysts as solid acid heterogeneous catalysts. This process was deeply investigated in recent years with good results. At the moment, the lifetime of the catalyst is the most crucial issue in industrial applications. With the aim of investigating this aspect, 90 consecutive batch deacidification runs, each lasting 6 h, were conducted using crude palm oil or soybean oil as a feedstock and Amberlyst 46 as a catalyst. At the end of the recycles, a decrease of activity of about 25% was observed, probably ascribed to some fragmentation of the catalyst’s particles, with a loss of active material, caused by the mechanical stress occurring in the batch reactor. The same reaction was also conducted in both continuous and semicontinuous catalytic packed-bed reactors, in order to immobilize the catalyst so as to prevent mechanical stress. A catalytic packed-bed reactor needs to be fed with a homogeneous methanol/vegetable oil emulsion: the results obtained with a traditional mechanical stirring and with an emulsificator were compared.

Biodiesel Production by Amorphous Carbon Bearing SO3H, COOH and Phenolic OH Groups, a Solid Brønsted Acid Catalyst

A solid Bronsted acid of amorphous carbon bearing SO3H, COOH and phenolic OH groups has been studied as a catalyst for biodiesel production. The carbon material functions as a stable and efficient catalyst for the formation of biodiesel from oleic acid at 353 K; the catalytic performance is 70–80% that of sulfuric acid. The carbon material also exhibits remarkable catalytic performance for transesterification of triolein at 403 K, maintaining high catalytic activity even in the presence of water. These results suggest that this catalyst can directly convert crude vegetable oils composed of triglycerides, free higher fatty acids and water into biodiesel with minimal energy consumption.