Oil transesterification over calcium oxides modified with lanthanum

Investigations were conducted on a series of calcium and lanthanum oxides catalyst for biodiesel production. Mixed oxides catalyst showed a superior transesterification activity over pure calcium or pure lanthanum oxide catalysts. The catalyst activity was correlated with surface basicity and specific surface areas. The effects of water and free fatty acids (FFA) levels in oil feedstock, water and CO₂ in air, mass ratio of catalyst, molar ratio of oil to methanol, and reaction temperature on fatty acid methyl ester (FAME) yield were investigated. Under optimal conditions, FAME yields reached 94.3% within 60 min at 58 °C. Mixed CaO-La₂O₃ catalyst showed a high tolerance to water and FFA, and could be used for converting pure or diluted unrefined/waste oils to biodiesel.     

Impact of the North Dakota Growing Location on Canola Biodiesel Quality

Canola biodiesel (fatty acid methyl esters, FAME) may have superior cold flow properties when compared to other biodiesel feedstocks, which is attributed to canola’s high unsaturated and low saturated fat content. The objective of this study was to evaluate canola biodiesel fatty acid composition, cloud point (CP) and oil stability index (OSI) among several ND locations and production years. In Experiment 1, bulked canola varieties from seven growing seasons (2003–2009) were analyzed and in Experiment 2 a single canola variety (Interstate Hyola 357RR) harvested at two locations (2003–2005, and 2007) were analyzed. FAME was produced directly from seed via in situ alkaline transesterification methods. CP ranged from −0.1 to −2.4 °C and was significantly impacted by year and location. FAME generally met the ASTM B100 specification for OSI (3 h), but increased seed storage decreased stability. No significant differences were detected in FAME composition, and iodine value ranged from 108 to 123 g I₂/100 g. A significant relationship between fat saturation and location with CP and stability was not detected among the samples in this study. Variation in fatty acid composition was small; thus, the significant variability in CP and OSI suggests either differences in minor constituents (antioxidants, waxes) or environmental seed stress impacted biodiesel quality. Our study supports the value of examining biodiesel quality in a canola breeding program.     

Esterification of sludge palm oil using trifluoromethanesulfonic acid for preparation of biodiesel fuel

Trifluoromethanesulfonic acid (TFMSA) was used to reduce the high free fatty acids (FFA) content in sludge palm oil (SPO). The FFA content of SPO was converted to fatty acid methyl ester (FAME) via esterification reaction. The treated sludge palm oil was used as a raw material for biodiesel production by transesterification process. Several working parameters were optimized, such as dosage of catalyst, molar ratio, reaction temperature and time. Less than 2% of the FFA content was the targeted value. The results showed that the FFA content of SPO was reduced from 16% to less than 2% using the optimum conditions. The yield of the final product after the alkaline transesterification was 84% with 0.07% FFA and the ester content was 96.7%. All other properties met the international standard specifications for biodiesel quality such as EN 14214 and ASTM D6751.     

Rubber seed oil as a potential source for biodiesel production in Bangladesh

In the present paper, rubber seed oil (RSO) has been investigated as a potential source for biodiesel production in Bangladesh. Rubber seed oil has been extracted from the rubber seeds collected from the local garden. Different methods have been applied for the oil extraction, such as mechanical press with and without solvent and cold percolation. Maximum oil content of 49% has been found by mechanical press with periodic addition of solvent. The physico-chemical properties of the oil have been investigated. Effect of seed storage time on free fatty acid (FFA) content of the oil is studied an it is found that the FFA content increases from 2 wt.% (fresh seed) to 45 wt.% after 2 months of storage at room temperature. Biodiesel has been prepared using a three-step method comprises with saponification of oil, acidification of the soap and esterification of FFA. Overall yield of FFA from RSO is found to be around 86%. The final step is esterification that produces fatty acid methyl ester (FAME). The effect of methanol to oil ratio and catalyst content has been investigated for esterification reaction. ¹H NMR spectrum of the RSO and biodiesel samples are analyzed which confirms the conversion of RSO to biodiesel. The biodiesel properties have been investigated and are found to be comparable with diesel.     

利用菜籽油脱臭馏出物制备生物柴油新工艺

以菜籽油脱臭馏出物为原料,首先以D002阳离子交换树脂作催化剂,进行酯化反应,降低原料酸值;然后以氢氧化钾作催化剂进行醇解反应来制备生物柴油的二步法新工艺路线。结果表明:D002阳离子交换树脂具有很强的催化活性,游离脂肪酸最高转化率达97.7%,连续使用4次后,催化活性仍然很高,达96%以上;碱催化过程中甘油酯的最高转化率达97.4%。产品品质大都符合美国ASTMD6751-03生物柴油标准。由此可见,先用树脂催化处理高酸值废油,然后进行碱催化制备生物柴油二步法工艺是一种切实可行的方法。     

Mesoporous Silica-Supported Diarylammonium Catalysts for Esterification of Free Fatty Acids in Greases

Biodiesel (BD), typically consisting of fatty acid methyl esters (FAME), has received much attention because it is a renewable biofuel that contributes little to global warming compared to petroleum-based diesel fuel. The most common method used for BD production is based on the alkali-catalyzed transesterification of first-use refined oils and fats with an alcohol (e.g. methanol). These technologies, however, require significant modification when applied to second use materials such as greases because of their higher free fatty acid (FFA) content. Recently, we reported a series of insoluble porous polymer grafted diphenylammonium salts that efficiently esterified the FFA in greases to FAME. In this work, the diphenylammonium salts were supported onto two robust mesoporous silicas. The resulting catalysts had high esterification activity with >99% of the FFA in greases converted to FAME, and the FFA content in the treated greases was reduced to <1 wt%. The mesoporous silica-supported catalysts displayed minimal transesterification activity.     

Production of biodiesel from palm fatty acid distillate using sulfonated-glucose solid acid catalyst:Characterization and optimization

A palm fatty acid distillate (PFAD) has been used for biodiesel production. An efficient sulfonated-glucose acid catalyst (SGAC) was prepared by sulfonation to catalyze the esterification reaction. The effect of three variables i.e. methanol-to-PFAD molar ratio, catalyst amount and reaction time, on the yield of PFAD esters was studied by the response surface methodology (RSM). The optimum reaction conditions were:12.2:1 methanol-to-PFAD molar ratio, 2.9%catalyst concentration and 134 min of time as predicted by the RSM. The reaction under the optimum conditions resulted in 94.5%of the free fatty acid (FFA) conversion with 92.4%of the FAME yield. The properties of the PFAD esters were determined according to biodiesel standards.     

Effects of partial hydrogenation, epoxidation, and hydroxylation on the fuel properties of fatty acid methyl esters

The properties of biodiesel depend on the chemical structure of individual fatty acid methyl esters (FAME). In this work the chemical structure of fatty acid chains was modified by catalytic hydrogenation, epoxidation and hydroxylation under controlled conditions. Hydrolysis of ester functionality or oxidation of fatty acid chain was not observed during these reactions. The properties of hydrogenated FAME strongly depend on the hydrogenation time. The total saturated fatty acid (SFA) percentage increased from 29.3% to 76.2% after 2 h of hydrogenation. This hydrogenated FAME showed higher oxidation stability and higher cetane number but poor cold flow properties. Formation of trans FAME was observed during hydrogenation. Both hydroxylation and epoxidation resulted in a decrease of unsaturated fatty acid methyl ester (UFA) fraction. The percentages of total unsaturated FAME decreased 39% in the epoxidation reaction and 44% in the hydroxylation reaction. The addition of hydroxyl groups to the unsaturated regions of the fatty acid chain yields biodiesel with better cold flow properties, increased lubricity and slightly increased oxidative stability. However, epoxy FAME shows some interesting properties such as higher oxidation stability, higher cetane number and acceptable cold flow properties, which met the limits of ASTM D6751 biodiesel specifications.     

Reduction of Free Fatty Acids in Acidic Nonedible Oils by Modified K10 Clay

Biodiesel is a biofuel obtained from vegetable oils. The oils used as raw materials are usually refined edible vegetable oils. Nonedible acidic oils are unsuitable for biodiesel production unless reduction of the high content in free fatty acids (FFA) of these materials had been achieved. Obtaining a good raw material from unprofitable oils becomes an important research field. Additionally clays have a long history in industrial sorption and catalysis, some being commercially available and with properties that can be modified. In this work we present the results of the use of the montmorillonite clay K10 and two acid modified clays K10(I) and K10(II), in the esterification of stearic acid with methanol and 95 % of methyl stearate was obtained with K10(II). These clays were then used for the first time to reduce the acidity of enhanced FFA sunflower oil and they show to be very effective. Reduction of FFA from 11 to 4 % was obtained with K10(II) mainly due to 94 % conversion of FFA into fatty acid methyl esters (FAME). These clays were also tested with two waste oils, one from domestic use and the other gathered from different restaurants, and showed their ability to lower the acidity of these oils. Reactions were followed by ¹H NMR as well as quantitative determination of FFA and FAME. Clays were characterized by FTIR and XRD.     

Improving the economics of biodiesel production through the use of low value lipids as feedstocks: vegetable oil soapstock

Semirefined and refined vegetable oils are the predominant feedstocks for the production of biodiesel. However, their relatively high costs render the resulting fuels unable to compete with petroleum-derived fuel. We have investigated the production of fatty acid methyl esters (FAME; biodiesel) from soapstock (SS), a byproduct of edible oil refining that is substantially less expensive than edible-grade refined oils. Multiple approaches were taken in search of a route to the production of fatty acid methyl esters from soybean soapstock. The most effective method involved the complete saponification of the soapstock followed by acidulation using methods similar to those presently employed in industry. This resulted in an acid oil with a free fatty acid (FFA) content greater than 90%. These fatty acids were efficiently converted to methyl esters by acid-catalyzed esterification. The fatty acid composition of the resulting ester product reflected that of soy soapstock and was largely similar to that of soybean oil. Following a simple washing protocol, this preparation met the established specifications for biodiesel of the American Society for Testing and Materials. Engine emissions and performance during operation on soy soapstock biodiesel were comparable to those on biodiesel from soy oil. An economic analysis suggested that the production cost of soapstock biodiesel would be approximately US$ 0.41/l, a 25% reduction relative to the estimated cost of biodiesel produced from soy oil.     

The effect of flux and residence time in the production of biodiesel from various feedstocks using a membrane reactor

Biodiesel produced from lipid sources is a clean-burning, biodegradable, nontoxic fuel that is free of aromatic hydrocarbons. Current biodiesel production processes are tedious and involve two to three reaction steps each followed by separation and purification. Process integration of reaction and separation in a single step within a membrane reactor (MR) offers several advantages over conventional reactors.This investigation is aimed at studying the effect of membrane flux and residence time on the performance of a membrane reactor in treating a variety of raw and used feedstocks. A membrane reactor having three selectable reactor volumes was designed to decouple the effect of residence time in the reactor from membrane flux on the performance of the reactor. Low free fatty acid (FFA) oils (FFA < 1%), i.e. canola, corn, sunflower and un-refined soy oils, and high FFA waste cooking oil (FFA = 5%) were base transesterified and the quality of the biodiesel produced was determined in terms of free glycerine, mono-glyceride, di-glyceride and tri-glyceride content. All oils were base transesterified without pretreatment.Based on the composition of the final product, the MR could be operated at the upper limit of the flux tested (70 L/m²/h) and a residence time of 60 min. The ASTM D6751 and EN 14214 standards for glycerin and glycerides were reached in the washed biodiesel product for all feedstocks and run conditions. The operating pressure in the reactor was exceeded at 70 L/m²/h in treating waste oils and pre-treated corn oil. For these oils, reasonable operating pressures in the reactor were reached at a membrane flux of 30–40 L/m²/h. The quality of the washed biodiesel always met ASTM and EN standards. The FAME produced from WCO at intermediate fluxes and high residence times met the ASTM and EN standards without water washing.     

Palm fatty acid biodiesel: process optimization and study of reaction kinetics

The relatively high cost of refined oils render the resulting fuels unable to compete with petroleum derived fuel. In this study, biodiesel is prepared from palm fatty acid (PFA) which is a by-product of palm oil refinery. The process conditions were optimized for production of palm fatty acid methyl esters. A maximum conversion of 94.4% was obtained using two step trans-esterification with 1:10 molar ratio of oil to methanol at 65°C. Sulfuric acid and Sodium hydroxide were used as acid and base catalyst respectively. The composition of fatty acid methyl esters (FAME) obtained was similar to that of palm oil. The biodiesel produced met the established specifications of biodiesel of American Society for Testing and Materials (ASTM). The kinetics of the trans-esterification reaction was also studied and the data reveals that the reaction is of first order in fatty acid and methanol (MeOH) and over all the reaction is of second order.     

Investigation of terminalia (Terminalia belerica Robx.) seed oil as prospective biodiesel source for North-East India

Terminalia (Terminalia belerica Robx.) is available in the northeastern region of India. The fruit of terminalia has some medicinal value and its kernel contains 43% oil. The prospect of terminalia oil for biodiesel production is investigated with reference to some relevant properties. The fatty acid profile of oil extracted from terminalia is found comparable with similar seed oils attempted for biodiesel production in this region. Terminalia oil contains 32.8% palmitic acid, 31.3% oleic acid, and 28.8% linoleic acid. The calorific value and kinematic viscosity of terminalia oil are 37.50 MJ/kg and 25.60 cSt, respectively. The calorific value and cetane number of terminalia FAME are within the acceptable limit of the EN 14214 standard. However, the flash point of terminalia FAME (90 °C) is relatively lower than the minimum required standard. Overall, the properties of biodiesel obtained from terminalia seed conform to the existing biodiesel standard. In addition to assisting the national biodiesel mission, the extension and regeneration of forest areas through terminalia planting would help us to curb the seemingly irreversible trend of de-forestation in the northeast region of India.     

Comprehensive utilization of the mixture of oil sediments and soapstocks for producing FAME and phosphatides

Comprehensive utilization of the mixture of oil sediments (OS) and soapstock (SS) for producing FAME and phosphatides was investigated. A process consisting of three steps was employed for obtaining high conversion and by-product. In the first step, the OS–SS mixture was extracted with ethyl ether and the mixture was divided into three phases. The organic top phase contained triglycerides and phosphatides was extracted with cooled acetone and the acetone insoluble (phosphatides) was obtained. At the same time, triglycerides were separated also. In the second step, soap phase was then acidified with sulfuric acid to yield fatty acid. This “high-acid” acid oil was efficiently converted to methyl esters by acid-catalyzed esterification. The esterification reaction has been carried out with 5:1 methanol/oil (mol/mol) in the presence 3% H₂S0₄ (wt.%) as an acid catalyst at 85 °C for 5 h. FAME recovery under these conditions was 92.1% of theoretical. In the third step, alkaline catalyzed transesterification process converts the triglycerides to its mono-esters and glycerol. The optimized variables, 6:1 methanol/oil (mol/mol) with 1% NaOH (wt.%) reacted at 65 °C for 1 h, giving a maximum ester yield of 94%. Five important fuel properties of FAME from the OS–SS mixture were found to be comparable to those of No. 2 diesel fuel and conforming to both the American and German standards for biodiesel.     

Prospects of non-catalytic supercritical methyl acetate process in biodiesel production

Conventional biodiesel production methods utilize alcohol as acyl acceptor and produces glycerol as side product. Hence, with escalating production of biodiesel throughout the world, it leads to oversupply of glycerol and subsequently causes devaluation in the market. In this study, methyl acetate was employed as acyl acceptor in non-catalytic supercritical methyl acetate (SCMA) process to produce fatty acid methyl esters (FAME) and side product of triacetin, a valuable fuel additive instead of glycerol. Consequently, the properties of biodiesel produced (FAME and triacetin) are superior compared to conventional biodiesel method (FAME only). In this research, the effects of reaction temperature, reaction time and molar ratio of methyl acetate to oil on the yield of biodiesel were investigated. Apart from that, the influence of impurities commonly found in waste oils/fats such as free fatty acids and water were studied as well and compared with methanol-based reactions of supercritical and heterogeneous catalysis. Results show that biodiesel yields in SCMA process could achieve 99 wt.% when the operating conditions were fixed at 400 °C/220 bar for reaction temperature, methyl acetate/oil molar ratio of 30:1 and 60 min of reaction time. Furthermore, SCMA did not suffer from adverse effect with the presence of impurities, proving that SCMA has a high tolerance towards contamination which is crucial to allow the utilization of inexpensive waste oils/fats as biodiesel feedstock.     

Production of fatty acid methyl esters over a limestone-derived heterogeneous catalyst in a fixed-bed reactor

Production of fatty acid methyl esters (FAME) via the transesterification of different vegetable oils and methanol with a limestone-derived heterogeneous catalyst was investigated in a fixed-bed reactor at 65 °C and ambient pressure. This heterogeneous catalyst, as a 1 or 2 mm cross-sectional diameter extrudate, was prepared via a wet mixing of thermally treated limestone with Mg and Al compounds as binders and with or without hydroxyethyl cellulose (HEC) as a plasticizer, followed by calcination at 800 °C. The physicochemical properties of the prepared catalysts were characterized by various techniques. Palm kernel oil, palm oil, palm olein oil and waste cooking oil could be used as the feedstocks but the FFA and water content must be limited. The extrudate catalyst prepared with the HEC addition exhibited an enhanced formation of FAME due to an increased porosity and basicity of the catalyst. The FAME yield was increased with the methanol/oil molar ratio. The effect of addition of methyl esters as co-solvents on the FAME production was investigated. The structural and compositional change of the catalysts spent in different reaction conditions indicated that deactivation was mainly due to a deposition of glycerol and FFA (if present). The FAME yield of 94.1 wt.% was stably achieved over 1500 min by using the present fixed-bed system.     

Reduction of high content of free fatty acid in sludge palm oil via acid catalyst for biodiesel production

In this study, sulphuric acid (H₂SO₄) was used in the pretreatment of sludge palm oil for biodiesel production by an esterification process, followed by the basic catalyzed transesterification process. The purpose of the pretreatment process was to reduce the free fatty acids (FFA) content from high content FFA (> 23%) of sludge palm oil (SPO) to a minimum level for biodiesel production (> 2%). An acid catalyzed esterification process was carried out to evaluate the low content of FFA in the treated SPO with the effects of other parameters such as molar ratio of methanol to SPO (6:1-14:1), temperature (40-80 °C), reaction time (30-120 min) and stirrer speed (200-800 rpm). The results showed that the FFA of SPO was reduced from 23.2% to less than 2% FFA using 0.75% wt/wt of sulphuric acid with the molar ratio of methanol to oil of 8:1 for 60 min reaction time at 60 °C. The results on the transesterification with esterified SPO showed that the yield (ester) of biodiesel was 83.72% with the process conditions of molar ratio of methanol to SPO 10:1, reaction temperature 60 °C, reaction time 60 min, stirrer speed 400 rpm and KOH 1% (wt/wt). The biodiesel produced from the SPO was favorable as compared to the EN 14214 and ASTM D 6751 standard.     

Production of high-quality biodiesel fuels from various vegetable oils over Ti-incorporated SBA-15 mesoporous silica

Ti-incorporated SBA-15 mesoporous silica (shortly termed Ti-SBA-15) was a highly efficient and recyclable solid acid to synthesize high-quality biodiesel fuel (BDF) derived from various vegetable oils at moderate reaction condition, in comparison to siliceous SBA-15 and commercial TiO₂ catalysts with different anatase sizes, where the catalytically active sites mainly related to the tetrahedral-coordinated Ti(IV) species with weak Lewis acid nature. The TOF values of Ti-SBA-15 catalysts were around 18–166 h^− 1, an order of magnitude larger than those of commercial TiO₂ catalysts. A high-quality BDF containing more than 98.4 mass% of fatty acid methyl ester (FAME), which met with international fuel standard, was obtained over 3Ti-SBA-15 catalyst at 200 °C using a methanol/oil ratio of 108. Most importantly, the 3Ti-SBA-15 catalyst showed extremely high water and free fatty acid (FFA) tolerance levels, which were several ten times better than homogeneous and heterogeneous catalysts in conventional BDF production technology.     

Distribution of soap in a membrane reactor in the production of fame from waste cooking oil

A continuous‐flow membrane reactor was constructed for the production of fatty acid methyl ester (FAME) from waste vegetable oil with high free fatty acid (FFA) content. FAME was produced via base‐catalysed transesterification with methanol at two FFA levels: 4.8 and 10 mass%. The effect of the ceramic membrane pore size on the separation of soap and triglycerides from the FAME in the reactor was investigated. In all cases, the triglyceride was completely retained in the reactor, yielding free and total glycerine contents in the produced FAME significantly below the maximum limits of the ASTM D6751 standard. The soaps produced in the reaction mixture were not completely retained in the reactor and did not affect the FAME production process. © 2012 Canadian Society for Chemical Engineering     

Comparisons of Biodiesel Produced from Unrefined Oils of Different Peanut Cultivars

Biodiesels were prepared according to standard procedures from unrefined oils of eight commercially available peanut cultivars and compared for differences in physical properties important to fuel performance. Dynamic viscosity, kinematic viscosity and density were measured from 100 to 15 °C, and differences (p < 0.05) in these physical properties occurred more frequently at lower temperatures when comparing the different cultivars. Unlike data for the oil feedstocks, no meaningful correlations among biodiesel fatty acid profiles and either fuel viscosity or density were observed. Low temperature crystallization of the peanut biodiesels was measured via differential scanning calorimetry. Increased concentrations of long chain saturated fatty acid methyl esters (FAME) were associated with an increased propensity for low temperature crystallization, and the single FAME category most associated with low temperature crystallization was C:24. Tempering at 10 °C followed by analysis of the soluble fractions (winterization), improved crystallization properties and confirmed the importance that long chain saturated FAMEs play in the final functionality of peanut biodiesel. Peanut data is also compared to data for canola and soy biodiesels, as these feedstocks are more common worldwide for biodiesel production. Overall, this work suggests that minimizing the concentration of long chain saturated FAMEs within peanut biodiesel, either through processing and/or breeding efforts would improve the low temperature performance of peanut biodiesel.