An improvement to the transesterification process by the use of co-solvents to produce biodiesel (original) (raw)
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Production of Biodiesel in the Presence of Co-Solvents in Transesterification: A Review
Consumption of fossil fuels has resulted in several economic and environmental consequences, prompting a quest for renewable energy sources rather than a reliance on fossil fuels. Biodiesel is a renewable source of energy that can be substituted for fossil fuel-based diesel fuel. Transesterification is the most economically viable way of producing biodiesel. However, the biodiesel manufacturing method based on transesterification has a disadvantage due to the immiscibility of the two key reactants, alcohol and oil, which results in a mass transfer resistance and reduces biodiesel yield. Several researchers have investigated using another solvent called a co-solvent to overcome the mass transfer barrier in the reaction medium. The purpose of this review was to examine the influence of several co-solvents on biodiesel synthesis that had been previously investigated the research.
Transesterification for biodiesel-a review
International Journal of Advanced Trends in Computer Science and Engineering, 2019
Synthesis of fuel from various low cost feed stocks solves the problem of solid waste management while synthesizing the biofuel. In transesterification, the oil is converted to biodiesel. Transesterification can be categorized into three categories namely base catalyzed, acid catalyzed and acid-base catalyzed. Also lipase made transesterification is one another category of such reactions. Transesterification consists of number of reversible reactions. Microwave assisted and ultrasonic transesterification are two advanced categories of transesterification reactions. The economy of transesterification process depends largely on the use of feed stock. Also use of appropriate catalyst has a major role to play. The performance of the reaction process with use of various acid, base and organic catalysts is one promising field of investigation. Transesterification of the palm oil and seed oil is widely investigated research area. Various aspects of this process such as catalyst use, affecting parameters, starting materials, reaction steps, kinetics and modeling are are being studied in order to make the process more acceptable and practical on industrial scale.
Technical aspects of biodiesel production by transesterification—a review
Renewable and sustainable energy …, 2006
Biodiesel is gaining more and more importance as an attractive fuel due to the depleting fossil fuel resources. Chemically biodiesel is monoalkyl esters of long chain fatty acids derived from renewable feed stock like vegetable oils and animal fats. It is produced by transesterification in which, oil or fat is reacted with a monohydric alcohol in presence of a catalyst. The process of transesterification is affected by the mode of reaction condition, molar ratio of alcohol to oil, type of alcohol, type and amount of catalysts, reaction time and temperature and purity of reactants. In the present paper various methods of preparation of biodiesel with different combination of oil and catalysts have been described. The technical tools and processes for monitoring the transesterification reactions like TLC, GC, HPLC, GPC, 1 H NMR and NIR have also been summarized. In addition, fuel properties and specifications provided by different countries are discussed. q
Biodiesel production by enzyme-catalyzed transesterification
Hemijska industrija, 2005
The principles and kinetics of biodiesel production from vegetable oils using lipase-catalyzed transesterification are reviewed. The most important operating factors affecting the reaction and the yield of alkyl esters, such as: the type and form of lipase, the type of alcohol, the presence of organic solvents, the content of water in the oil, temperature and the presence of glycerol are discussed. In order to estimate the prospects of lipase-catalyzed transesterification for industrial application, the factors which influence the kinetics of chemically-catalysed transesterification are also considered. The advantages of lipase-catalyzed transesterification compared to the chemically-catalysed reaction, are pointed out. The cost of down-processing and ecological problems are significantly reduced by applying lipases. It was also emphasized that lipase-catalysed transesterification should be greatly improved in order to make it commercially applicable. The further optimization of lip...
2016
In the recent times the biodiesel has becomes one of the most notable alternative fuel for diesel engines because of owing to biodegradability, renewability and low toxicity. The biodiesel is produced by a variety of feedstocks such as edible oil, non-edible oil and waste cooking oil. Transesterification process is generally used for biodiesel production. In transesterification process catalysts are used for carrying out the reaction. In the reaction the catalyst performs a crucial role in the conversion of biodiesel of free acid or feed stocks to respective esters at faster rate and in minimum reaction temperature. The production of biodiesel by transesterification have been done by several researchers using methanol or ethanol along with catalysts of different kinds catalyst. The catalysts used for production of biodiesel are homogeneous and heterogeneous catalysts. Several researchers have worked on development of homogeneous and heterogeneous catalysts for transesterification pr...
Transesterification with heterogeneous catalyst in production of biodiesel: a review
Journal of Chemical and Pharmaceutical Research, 2013
Biodiesel, an alternative and renewable fuel for diesel engines, has become more attractive in recent times because of its renewability, biodegradability, nontoxicity and carbon neutrality. Biodiesel consists of mono alkyl esters of long chain fatty acids, more commonly methyl esters and is typically made from biological resources such as plant seed oils, animal fats or even waste cooking oils by transesterification with methanol. Transesterification reactions are catalyzed by acids, bases and enzymes. Heterogeneous catalysts are promising and receiving attention for the production of biodiesel. In the present paper, an attempt is being made to review on heterogeneous catalyst used in the production of biodiesel.
Biodiesel production by two-stage transesterification with ethanol
Bioresource Technology, 2011
A two-stage process consisting of two reactions steps with glycerin separation and ethanol/catalyst addition in each of them was optimized for ethyl esters production. The optimal reaction temperature was 55 °C. At an ethanol/oil molar ratio of 4.25:1 (25% v/v alcohol with respect to oil), a 99% conversion value was obtained with low ethanol consumption. In contrast to methoxide catalysts, sodium and potassium hydroxide catalysts severely complicate the purification since no phase separation took place under most conditions. With a total sodium methoxide concentration of 1.06 g catalyst/100 g oil, and adding 50% of the catalyst in each reaction step, biodiesel with a total glycerin content of 0.172% was obtained. The optimal conditions found in this study make it possible to use the same industrial facility to produce either methyl or ethyl esters.► High quality ethanol based biodiesel is produced carrying out the reaction in a two-stage process. ► Experimental conditions were selected in order to maximize the reaction conversion. ► The conversion as required in international quality standards are met with mild reaction conditions. ► Catalyst and alcohol consumptions are similar to those used in the methanol process.
Catalysis in Biodiesel Production by Transesterification Processes-An Insight
EJ Chem, 2010
Biodiesel is the mono-alkyl esters of long chain fatty acids derived from renewable lipid feedstock, such as vegetable oils and animal fats, for use in compression ignition (diesel) engines. The conversion of component triglycerides in oils to simple alkyl esters with short chain alcohols like methanol and ethanol amongst others is achieved mainly by transesterification. The transesterification reaction, a reversible process proceeds appreciably by the addition of catalysts, which can be acidic, basic or organic in nature, usually in molar excess of alcohol. The economy of the process depends on the type and quantity of catalyst used among other factors. The catalyst can be homogeneous or heterogeneous depending on whether it is in the same or different phase with the reactants; oils and alcohols. This paper attempts to give an insight into some of the various types of catalysts that have been used to effect the transesterification of vegetable, waste and animal oils in biodiesel production.
REVIEW Biodiesel Fuel Production by Transesterification of Oils
Biodiesel (fatty acid methyl esters), which is derived from triglycerides by transesterification with methanol, has attracted considerable attention during the past decade as a renewable, biodegradable , and nontoxic fuel. Several processes for biodiesel fuel production have been developed, among which transesterification using alkali-catalysis gives high levels of conversion of triglycer-ides to their corresponding methyl esters in short reaction times. This process has therefore been widely utilized for biodiesel fuel production in a number of countries. Recently, enzymatic trans-esterification using lipase has become more attractive for biodiesel fuel production, since the glyc-erol produced as a by-product can easily be recovered and the purification of fatty methyl esters is simple to accomplish. The main hurdle to the commercialization of this system is the cost of lipase production. As a means of reducing the cost, the use of whole cell biocatalysts immobilized within biomass support particles is significantly advantageous since immobilization can be achieved spontaneously during batch cultivation, and in addition, no purification is necessary. The lipase production cost can be further lowered using genetic engineering technology, such as by developing lipases with high levels of expression and/or stability towards methanol. Hence, whole cell bio-catalysts appear to have great potential for industrial application.
A Simple Engineering Technique to Improve Transesterification for Biodiesel Fuel Production
JOURNAL OF CHEMICAL ENGINEERING OF JAPAN, 2013
The transesteri cation of triglyceride with methanol using an alkali catalyst was experimentally measured, and the obtained equilibrium constants were analyzed by the van't Ho model. The constant for the conversion of triglyceride to diglyceride was the smallest. The standard enthalpies of formation in the transesteri cation were measured to be positive, i.e., the reaction is endothermic. Next, the transesteri cation using the countercurrent multistage reactor system was computationally simulated with the equilibrium stage model, in which the equilibrium constants obtained above were used. The concentrations of the triglyceride remaining in the biodiesel fuel product drastically decreased by the reactor staging, and consequently the reaction temperature and the required amount of methanol could be reduced. The transesteri cation by the countercurrent multistage reactor was found to be attractive because of the e cient production of the biodiesel fuel.
Biodiesel fuel production by transesterification of oils
Journal of bioscience and bioengineering, 2001
Biodiesel (fatty acid methyl esters), which is derived from triglycerides by transesterification with methanol, has attracted considerable attention during the past decade as a renewable, biodegradable, and nontoxic fuel. Several processes for biodiesel fuel production have been developed, among which transesterification using alkali-catalysis gives high levels of conversion of triglycerides to their corresponding methyl esters in short reaction times. This process has therefore been widely utilized for biodiesel fuel production in a number of countries. Recently, enzymatic transesterification using lipase has become more attractive for biodiesel fuel production, since the glycerol produced as a by-product can easily be recovered and the purification of fatty methyl esters is simple to accomplish. The main hurdle to the commercialization of this system is the cost of lipase production. As a means of reducing the cost, the use of whole cell biocatalysts immobilized within biomass support particles is significantly advantageous since immobilization can be achieved spontaneously during batch cultivation, and in addition, no purification is necessary. The lipase production cost can be further lowered using genetic engineering technology, such as by developing lipases with high levels of expression and/or stability towards methanol. Hence, whole cell biocatalysts appear to have great potential for industrial application.
Biodiesel Production by Transesterification A Rev iew
Biodizel günümüzün en popüler alternatif yakıtlarından biridir. Makalede biodizelin üretim prosesi, alternatif yakıt olarak değeri, ne kadar alternatif olduğu mevzuları irdelenmektedir. Makalede biodizel üretiminde kullanılan prosesler sırayla tanımlanıp; a) Baz katalizi ile transesterleme b) Asit katalizi ile transesterleme c) Lipaz enzimi uygulanması d) Proliz e) Mikrodalga uygulanması f) Ultrasonik ses uygulanması Gibi prosesler mukayese edilmekte, en uygun prosesin tanımlanmasına çalışılmaktadır.
Review of Catalytic Transesterification Methods for Biodiesel Production
Biofuels - State of Development, 2018
Attempts for improving the synthesis procedure of catalysts for fatty acid methyl ester production have been progressing for a considerable length of time. Biodiesel lessens net carbon dioxide emissions up to 78% with reference to conventional fuel. That is the reason for the improvement of new and operative solid catalysts necessary for inexhaustible and efficient fuel production. Homogenous base catalysts for transesterification is risky in light of the fact that its produces soap as byproduct, which makes difficult issues like product separation and not temperate for industrial application. In comparison, heterogeneous process gives higher quality FAME which can be effectively isolated and facilitate costly refining operations that are not required. A focus of this review article is to study and compare various biodiesel synthesis techniques that are being researched. The catalytic strength of numerous heterogeneous solid catalysts (acid and base), specially earth and transition metal oxides were also appraised. It was observed that catalytic proficiency relied upon a few factors, for example, specific surface area, pore size, volume and active site concentration at catalyst surface. This review article will give assistance in assortment of appropriate catalysts and the ideal conditions for biodiesel generation.
Fuel, 2012
In this study, the transesterification double step process (TDSP) was modified to enable the usage of ethanol as a transesterification agent in the production of biodiesel from vegetable and waste oils. The TDSP comprises a two-step transesterification procedure, which is initiated by a homogeneous basic catalysis step and followed by an acidic catalysis step. To optimize the transesterification parameters, different reaction mixtures and conditions were tested. Compared with methanol transesterification, larger ethanol and catalyst amounts as well as higher reaction times and temperatures were required. However, the results were consistent with those usually reported for ethanol transesterification. The obtained biodiesels (i.e., fatty acid ethyl esters (FAEEs)) were analyzed by standard physico-chemical techniques in addition to 1 H NMR, 13 C NMR and FTIR spectroscopies, indicating high quality and purity biodiesel products. The obtained conversions were evaluated by 1 H NMR spectroscopy. For the optimized process, the triglyceride conversion to biodiesel was P97% for all oils used. The overall process yields are considerably high when compared to the single basic catalysis yields.
Energy Conversion and Management, 2014
Solvent Technology, is gaining the interest of researchers in improving transesterification process recently. Transesterification of cotton seed oil into biodiesel using different mixtures of methanol with Diethyl Ether (DEE), Dichlorobenzene (CBN) or Acetone (ACT) co-solvent systems was conducted. Potassium hydroxide (KOH) was used as the catalyst all through. The reaction conditions optimized include; the molar ratio of co-solvent in methanol, reaction temperature and time. The catalyst concentration was also optimized. The optimization was based on the percentage yields of Fatty Acids Methyl Esters (FAMEs) produced. In addition, the effects of co-solvent systems on physico-chemical properties (Acid value and fatty acids composition) and fuel properties (viscosity, density and calorific value) were investigated as well. The result obtained, indicated 10% (v/v) addition of co-solvents CBN and ACT in methanol was the optimal volume. The optimal reaction temperature was 55°0C for 10 min when the catalyst concentration of 0.75% (w/w) weight of oil was used. Fuel properties were within the acceptable limit of ASTM and not significantly affected by the co-solvent systems except for the calorific value. It was concluded that the addition of co-solvent reduced the reaction time and improved some fuel properties of the biodiesel produced.
Optimizing the Various Parameters for Biodiesel Production by Transesterification
2015
Steep hikes of petroleum prices and rising demand of petroleum products compile the scientific society to think for the renewable alternative fuels like biodiesel. Biodiesel production is generally carried out through the process of trans-esterification reaction. The reaction is facilitated with a suitable catalyst either homogeneous or heterogeneous. The selection of appropriate catalyst depends on the amount of free fatty acids in the oil. As per the current scenario of rapid increase in the usage of automobiles, the demand for the fuel also increases drastically. In the present study the raw neem oil is converted into biodiesel by using transesterification process and to optimize the various parameters of biodiesel production.
Journal of Petroleum and Mining Engineering, 2021
Biodiesel is a type of biofuel that has a composition and combustion properties similar to petrodiesel fuel. Renewable resources such as vegetable oil, algae, and animal fats are crucial feedstocks for biodiesel production. Biodiesel is a renewable and clean fuel as it reduces carbon monoxide, carbon dioxide, hydrocarbons, and particulate matter emissions compared with petroleum-based diesel fuel. The conversion of vegetable oil to alkyl esters (biodiesel) depends upon certain parameters that affect the biodiesel production process such as catalyst concentration, methanol to waste cooking oil ratio, temperature, mixing rate, and reaction time. In this paper, the effect of reaction parameters on the yield quantity and properties will be shown
A review on biodiesel production using catalyzed transesterification
Applied Energy, 2010
Biodiesel is a low-emissions diesel substitute fuel made from renewable resources and waste lipid. The most common way to produce biodiesel is through transesterification, especially alkali-catalyzed transesterification. When the raw materials (oils or fats) have a high percentage of free fatty acids or water, the alkali catalyst will react with the free fatty acids to form soaps. The water can hydrolyze the triglycerides into diglycerides and form more free fatty acids. Both of the above reactions are undesirable and reduce the yield of the biodiesel product. In this situation, the acidic materials should be pre-treated to inhibit the saponification reaction. This paper reviews the different approaches of reducing free fatty acids in the raw oil and refinement of crude biodiesel that are adopted in the industry. The main factors affecting the yield of biodiesel, i.e. alcohol quantity, reaction time, reaction temperature and catalyst concentration, are discussed. This paper also described other new processes of biodiesel production. For instance, the Biox co-solvent process converts triglycerides to esters through the selection of inert co-solvents that generates a one-phase oil-rich system. The non-catalytic supercritical methanol process is advantageous in terms of shorter reaction time and lesser purification steps but requires high temperature and pressure. For the in situ biodiesel process, the oilseeds are treated directly with methanol in which the catalyst has been preciously dissolved at ambient temperatures and pressure to perform the transesterification of oils in the oilseeds. This process, however, cannot handle waste cooking oils and animal fats.
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A Comprehensive Review on Oil Extraction and Biodiesel Production Technologies
Sustainability
Dependence on fossil fuels for meeting the growing energy demand is damaging the world’s environment. There is a dire need to look for alternative fuels that are less potent to greenhouse gas emissions. Biofuels offer several advantages with less harmful effects on the environment. Biodiesel is synthesized from the organic wastes produced extensively like edible, non-edible, microbial, and waste oils. This study reviews the feasibility of the state-of-the-art feedstocks for sustainable biodiesel synthesis such as availability, and capacity to cover a significant proportion of fossil fuels. Biodiesel synthesized from oil crops, vegetable oils, and animal fats are the potential renewable carbon-neutral substitute to petroleum fuels. This study concludes that waste oils with higher oil content including waste cooking oil, waste palm oil, and algal oil are the most favorable feedstocks. The comparison of biodiesel production and parametric analysis is done critically, which is necessary...
Green Chemistry Letters and Reviews
Although fossil fuels remain the main source of energy, the volume of renewable sources of energy is constantly increasing. Biodiesel is a promising alternative fuel due to the number of advantages compared to fossil fuel and other types of biofuel. The specific objective of this study was to identify the difference between conventional and novel technologies applied during the whole life cycle of biodiesel production and consumption. The study offers some important insights into the recent advances in the biodiesel industry including biodiesel production from microalgal lipids, advanced homogenous and enzymatic transesterification, non-catalytic supercritical transesterification, application of microwave and ultrasound assisting technologies. Considering all the factors affecting the efficiency and safety of the biodiesel production process, here we reviewed the main principals and recent achievements in the environmental life cycle assessment of biodiesel production and consumption.
Micro-Reactor Device For Dbsa-catalyzed Biodiesel Synthesis from Microalgae Chlorella Sp
2020
The micro-reactor device was fabricated from Teflon and tested as a tool for biodiesel synthesis process from micro algae using Dodecylbenzenesulfonic acid catalyst. The variables influenceing on the biodiesel yield were optimized. The maximum yield of biodiesel of 99% was obtained at the reaction conditions of (temperature: 373.15 K, residence time: 20 min, methanol/oil ratio: 20, co-solvent amount: 30 wt% and catalyst amount: 11wt%). The influence of water content also investigated and recommended to be less than 0.5 wt %. The acid value also reduced to a value of less than 0.5 % at the optimum reaction condition. DBSA was found highly active catalyst for the esterification and transesterification reaction in the micro – reactor device. Biodiesel was produced in microreactor device at a small residence time (20 min) compared to the very long time consumed by the conventional batch process. Isopropanol was used as a co-solvent in the process and showed highly active in the biodiese...
ACS Omega, 2022
Biodiesel is one of the emerging renewable sources of energy to replace fossil-fuel-based resources. It is produced by a transesterification reaction in which a triglyceride reacts with methanol in the presence of a catalyst. The reaction is slow because of the low solubility of methanol in triglycerides, which results in low concentrations of methanol available to react with triglyceride. To speed up the reaction, cosolvents are added to create a single phase which helps to improve the concentration of methanol in the triglyceride phase. In this study, molecular dynamics simulations are used to help understand the role of cosolvents in the solvation of triglyceride (triolein). Six binary mixtures of triolein/cosolvent were used to study the solvation of triolein at 298.15 K. Results of 100 ns simulations at constant temperature and pressure to simulate mixing experiments show that in the first 10 ns all the binary mixtures remain largely unmixed. However, for the cosolvents that are fully miscible with triolein, the partial densities across the simulation boxes show that the systems are fully mixed in the final 10 ns. Some solvents were found to interact strongly with the polar part of triolein, while others interacted with the aliphatic part. The radial distribution functions and clustering of the solvents around triolein were also used as indicators for solvation. The presence of cosolvents also influenced the conformation of triolein molecules. In the presence of solvents that solubilize it, triolein preferred a propeller conformation but took up a trident conformation when there is less or no solubilization. The results show that tetrahydrofuran is the best solvent at solubilizing triolein, followed by cyclopentyl methyl ether, diethyl ether, and hexane. With 1,4-dioxane, the solubility improves with an increase in temperature. The miscibility of a solvent in triolein is aided by its ability to interact with both the polar and nonpolar parts of triolein.
Sunflower oil transesterification with methanol using immobilized lipase enzymes
Bioprocess and biosystems engineering, 2018
The transesterification of sunflower oil with methanol, using immobilized lipase enzymes as catalysts, was studied. The process was carried out in a semi-continuous mode. Temperature (30-50 °C), methanol flow (0.024-0.04 ml/min), kind of enzyme (Lipozyme 62350, Lipozyme TL-IM, Novozym 435 and Pseudomonas cepacia Sol-Gel-AK) and enzyme concentrations (1.25-10% by weight) were the operating variables. The final product was characterized by the EN 14214 standard. All the parameters, except for cold filter plugging point, were similar to a diesel fuel. For low methanol flows, reaction rate was proportional to methanol concentration. High flows caused catalyst deactivation. Novozyme 435, Lipozyme TL-IM and Lipozyme 62350 showed similar maximum reaction rates, but Novozyme 435 was more resistant to deactivation. Pseudomonas cepacia hardly obtained 1% conversion. The catalyst concentration, up to 2.5%, had a positive effect on the reaction rate and conversion. The optimum temperature was 4...
BioEnergy Research
The main objective of this study is to design and simulate three different continuous processes, namely, homogeneous and heterogeneous alkali-catalyzed and supercritical methanolysis processes to produce biodiesel at a production rate of 100,000 t/year from virgin vegetable oil. Tetrahydrofuran (THF) was used as a cosolvent at different concentrations of 25 wt.%, 30 wt.%, and 1.63 wt. % for the homogeneous and heterogeneous alkali-catalyzed and supercritical processes, respectively. An economic assessment and a sensitivity analysis were performed based on the results of the process design and simulation. Technical assessment of the proposed processes indicated that the homogeneous and heterogeneous alkali-catalyzed processes were the simplest, where the least amount of process equipment were used. whereas the supercritical methanolysis process was more complex, which used a large number of transesterification and separation units. The homogeneous alkali-catalyzed process that used T...
Miscibility and mass transfer in biodiesel production observed by LCD digital microscope
Biomass Conversion and Biorefinery, 2020
The mutual solubilities of multiple components in the transesterification reaction are among the key factors affecting biodiesel production. In the experiments, refined palm oil (RPO) and fatty acid methyl ester (FAME) were the main reactants, and methanol was added. Sodium methoxide and sulfuric acid were used as alkaline and acid catalysts, respectively. The co-solvent, tetrahydrofuran (THF), was used to improve solubility. Visual observations with an LCD digital microscope were done at room temperature to eliminate methanol loss. A concave slide glass was employed as a micro-reactor for observing mass transport in the reaction zone. The imaging results showed that the multi-component reactions in biodiesel production were of heterogeneous liquid-liquid type. The by-products glycerol and soap play significant roles as reaction barrier and suspension component in the system, while the added THF did not induce complete solubility. The kinetics of heterogeneous liquid-liquid transesterification or esterification reactions should be revised to properly account for both mass transfer and chemical reactions. Multistage combinations of separation of the alcohol phase and of new alcohol intake should be employed to reduce mass transfer resistances by glycerol and soap, to speed up overall kinetics.
The effect of BHA on oxidative stability of biodiesel from different sources
Greenhouse Gases: Science and Technology, 2020
The use of biodiesel is important, as it is a more sustainable energy source, obtained in many cases from vegetable oils and wastes such as fried used oils. In that way, there are plenty of advantages derived from its use, such as higher flash and combustion points. On the other hand, the oxidative stability of these samples is shorter, not complying with the European standards. That is the reason why the use of antioxidants, such as butylated hydroxyanisole (BHA), is vital to comply with the standards and make biodiesel marketable. The aim of this research work was to study the effect of BHA at different concentrations (up to 2000 ppm, depending on the kind of sample) on several biodiesel samples derived from several vegetable oils (rapeseed, seed, and used fried oils). The results obtained pointed out the improvement of the induction point for all the samples as BHA concentration increased. Moreover, there was an influence of the raw material composition (concerning fatty acid profile) on the induction point of the biodiesel obtained and the subsequent optimum concentration of BHA. Thus, the fatty acid profile was different depending on the sample, and the higher amount of methyl linoleate of seed and used fried biodiesel was important, which implied shorter induction points in these samples. As a consequence, for the latter, higher amounts of BHA (around 1400 ppm) were needed. As a conclusion, all the samples studied showed suitable oxidative stability values (over 8 hours) with the use of BHA (at variable optimum concentrations).
ACS Omega
The acid-catalyzed pre-treatment esterification process is required for low-cost feedstock with high free fatty acids (FFAs) to avoid the saponification that occurs during alkali-catalyzed transesterification for the production of fatty acid alkyl esters (FAAE). Reverse hydrolysis in acid-catalyzed esterification causes a decrease in fatty acid methyl ester (FAME) yield. Therefore, the esterification process must be intensified. This study aims to develop and optimize a low-temperature intensification process to enhance biodiesel yield and reduce energy consumption. Three intensification systems were studied: co-solvent technique, cosolvent coupled with adsorption of water using molecular sieves, and entrainer-based continuous removal of water. The process variables of esterification reaction in co-solvents without the adsorption system were optimized by using central composite design (CCD). The study showed that the co-solvent without the adsorption system was effective in intensifying the FFA conversion (X FFA) at low temperatures, compared to the other two systems, due to the dilution effect at high co-solvent/entrainer amount required for sufficient vapors in the adsorption system. Optimized process variables have achieved 95% X FFA within 75 min at 55°C, 20 mL/100 g of oil DEE, 9 MR, 3 wt % H 2 SO 4 , and 320−350 RPM in a co-solvent without the adsorption system.
Catalysts, 2020
The transesterification of rapeseed and castor oil methyl esters with different alcohols (2-ethyl-1-hexanol, 1-heptanol and 4-methyl-2-pentanol) and titanium isopropoxide as a catalyst, to produce biolubricants, was carried out. Parameters such as temperature, alcohol/methyl ester molar ratio, and catalyst concentration were studied to optimize the process. The reaction evolution was monitored with the decrease in FAME concentration by gas chromatography. In general, the reaction was almost complete in two hours, obtaining over 93% conversions. All the variables studied influenced on the reaction yields. Once the optimum conditions for the maximum conversion and minimum costs were selected, a characterization of the biolubricants obtained, along with the study of the influence of the kind of alcohol used, was carried out. The biolubricants had some properties that were better than mineral lubricants (flash points between 222 and 271 °C), needing the use of additives when they do not...
Heterogeneous nanocatalysts for sustainable biodiesel production: A review
Journal of Environmental Chemical Engineering, 2021
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Safflower Biodiesel: Improvement of its Oxidative Stability by Using BHA and TBHQ
Energies, 2019
Biodiesel is gaining more and more importance due to environmental issues. This way, alternative and sustainable crops as new biofuel sources are demanded. Safflower could be a sustainable raw material for biodiesel production, showing one disadvantage (as many biodiesels from vegetable oils), that is, a short oxidative stability. Consequently, the use of antioxidants to increase this parameter is mandatory. The aim of this research work was to assess the effect of two antioxidants (butylated hydroxyanisole, BHA, and tert-butylhydroquinone, TBHQ) on the oxidative stability of safflower biodiesel, which was characterized paying attention to its fatty acid methyl ester profile. For oxidative stability, the Rancimat method was used, whereas for fatty acid profile gas chromatography was selected. For the remaining parameters, the methods were followed according to the UNE-EN 14214 standard. The overall conclusion was that safflower biodiesel could comply with the standard, thanks to the...
Green Processing and Synthesis, 2018
The kinetics of the alkali-catalyzed transesterification of sunflower oil with methanol in the presence of co-solvent (TSMPC) were investigated. The kinetics curves of the alkali-catalyzed TSMPC, in the temperature range of 26°C–55°C, were measured for conventional heating (CH) and microwave heating with controlled cooling. The results showed that for both heating modes, the kinetics of the alkali-catalyzed TSMPC reaction can be described with the kinetic model of the pseudo first-order reaction with respect to the concentration of the triglycerides. The values of apparent reaction rate constants, activation energies, and pre-exponential factors are also calculated. The existence of a linear correlation (compensation effect) between the values of apparent kinetic parameters determined for CH and microwave heating with controlled cooling conditions is established. The results confirmed that the increase in the transesterification rate in the microwave heating with controlled cooling ...
Glycerol Steam Reforming in a Pilot Plant: Effect of Temperature and Catalyst Load
Applied Sciences
One of the main environmental problems is the use of oil for fuel and plastic production, implying the increase in pollutants that might contribute to the greenhouse gas effect, among others. Thus, the use of vegetable oils to produce biodiesel can be interesting, as it is biodegradable and less pollutant compared to diesel fuels, presenting higher flash and combustion points. Moreover, biodiesel production could take part in a biorefinery concept, to produce products such as biolubricants and obtain interesting byproducts that can be reused (such as methanol) or upgraded for energy or pharmaceutical purposes (like glycerol). Consequently, the valorization of these byproducts could contribute to the higher energy efficiency of the process, improving the atom economy. The aim of this work was to assess the effect of the temperature and the amount of catalyst on glycerol steam reforming to produce hydrogen at a semi-industrial level, regarding some aspects like gas production, hydroge...