Ethyl Ester Yield Research Articles

An Efficient Utilization of Waste Date Pit Oil for Ethyl Ester Production

As a green material, used date pits oil is increasingly utilized as inexpensive feedstock for ethyl ester (biodiesel) production. Waste date pits as a raw material are one of the highly produced agricultural wastes in Iran. This study investigated the effect of several procedure parameters including the ethanol/oil molar ratio, reaction temperature and amount of catalysts on the yield of the produced ethyl ester. The activity of date pits oil can be considered a method of second-generation biofuels production including green diesel fractions. Efficient from waste date pits and synthesis of ethyl ester have made a breakthrough in biodiesel production. Gas chromatography/mass spectrometry (GC-MS) and Fourier Transform Infrared (FT-IR) were employed to determine the composition of production. The optimized ethyl ester yield obtained was 92% when the procedure temperature was 65 ℃, within 6h, with 7:1 ethanol/oil molar ratio with 0.75 wt.% of catalyst (KOH). Waste date pits oil as feedstock can be an efficient platform for ethyl ester production. The purified ethyl ester satisfies the stringent quality standards imposed by ASTM D-6751 (USA standard) and EN-14214 (European standard).

Valorization of sewage sludge via non-catalytic transesterification

To seek a way to valorize sewage sludge (SS), it was chosen as a raw material for biodiesel production. As such, non-catalytic transesterification of dried SS was carried out, to enhance its value. Note that picking a waste material such as SS as an inexpensive lipid feedstock for biodiesel production, without lipid extraction, greatly increases the economic viability of biodiesel. Also, to enhance biodiesel sustainability, ethanol (EtOH) was employed as the acyl acceptor, in this study, and this was experimentally justified by results showing that employing EtOH as an acyl acceptor provided an effective means for compensating for the lower heating value arising from the large amount of palmitic (C16) acid in SS. This study experimentally proved that the fatty acid ethyl ester (FAEE) yield at 380 °C reached up to 13.33 wt% of dried SS. Given that the lipid content of dried SS is 14.01 ± 0.64 wt%, the FAEE yield of 13.33 wt% implied that 95.14 wt% of lipid in dried SS had been converted into FAEEs. The introduced SS valorization in this study offered an excellent opportunity to address diverse environmental hazards arising from SS and associated emerging contaminants. Given that the optimal temperature for the non-catalytic conversion for biodiesel production from SS was found to be 380 °C, emerging contaminants, such as microplastics and antimicrobials, were simultaneously degraded, due to their inferior thermal stabilities. Lastly, considering that the introduced biodiesel conversion process is thermally induced, the SS reside after the biodiesel conversion process can be further used in thermo-chemical processes as raw materials for gasification and pyrolysis (future work).

Assessment of commercial acidic ion-exchange resin for ethyl esters synthesis from Acrocomia aculeata (Macaúba) crude oil

This study aimed to obtain ethyl esters (EEs) from macauba pulp crude oil, using heterogeneous-acid catalyst, varying the temperature of (trans)esterification, ethanol-to-oil molar ratio (MR) and catalyst content. Catalyst Amberlyst 15 characterization showed high concentrations of active sites of 3400 μmol g−1 and a surface area of 31.3 m2 g−1, which associated with the resin macroporous structure. A Central composite rotational design (CCRD) 2³ design and response surface methodology (RSM) were used to analyze the studied variables effects on the EEs production: temperature (80–180 °C), ethanol-to-oil MR (4–14) and catalyst Amberlyst 15 content (1–20 wt%). EEs formed were quantified by gas chromatography, and the RSM showed that the reaction presented EEs yields greater than 85% with a high index selectivity (817.4). The desirability procedure showed, that for both Free fatty acids (FFAs) conversion and EEs yield, the optimum conditions were the same, being 130 °C, ethanol-to-oil MR 9 and 16 wt% of catalyst. The biodiesel obtained was characterized and all the analyzed parameters agreed with the national biofuel-monitoring agency. The process conditions and the characterization of produced EEs showed that macauba crude pulp oil has good potential for biodiesel production using heterogeneous acid-catalyst.

ULTRASOUND-ASSISTED TRANSESTERIFICATION OF SOYBEAN OIL USING COMBI-LIPASE BIOCATALYSTS

Abstract We applied ultrasonic technology for the transesterification of soybean oil catalyzed by a mixture of lipases (combi-lipase: 75 % Novozym 435; 10 % Lipozyme TL-IM; and 15 % Lipozyme RM-IM), verifying the effects of ultrasonic amplitude, pulse conditions, the ethanol:oil molar ratio, enzyme concentration, and the influence of solvent (tert-butanol on the reaction. We also compared this system against ultrasound combined with mechanical stirring, and the efficiency of the combi-lipase, compared with the individual use of each lipase. The optimum conditions for the transesterification reaction were determined as enzyme concentration of 15 % (in relation to oil mass); ethanol:oil molar ratio of 3:1; ultrasonic amplitude of 30 %, duty cycle of 50 % and time pulse of 15 sec. The yields of conversion of ethyl esters with and without solvent were similar, indicating that the use of solvents during enzymatic transesterification reactions is not necessary when ultrasonic technology is applied to the system. The combination of mechanical stirring and ultrasound did not improve the yields of conversion compared to ultrasonic technology alone. The proposed combi-lipase produced higher yields of ethyl esters (75 %) than the individual lipases (55 %) in 5 h under ultrasonic-assisted batch reactions.

Enhancement of lipase transesterification activity by immobilization on β–cyclodextrin-based polymer

Silica–β-cyclodextrin matrices were prepared by the sol–gel technique using tetraethoxysilane as precursor and different concentrations (0.5–4.0%) of the organic component, β-cyclodextrin (β-CD). Hybrid matrices were activated with glutaraldehyde to introduce functional groups for the attachment of Burkholderia cepacia lipase, used here as a model enzyme. The goal was to produce biocatalysts with high activity and satisfactory properties for transesterification reactions. The biocatalysts exhibited similar hydrolytic activities, coupling yields, and kinetic parameters (Km and Vmax), but differed in terms of thermal stability and transesterification activity. The best biocatalyst, prepared using 2.0% β-CD, was used to study the influence of oil/alcohol molar ratio on ester yield, viscosity, and residual monoacylglycerol (MG) and diacylglycerol (DG) contents. The molar ratio of palm kernel oil to ethanol had a considerable effect on the formation of ethyl esters and the best performance was achieved with an oil/alcohol molar ratio of 1:6. Under this condition, a high ethyl ester yield, a low residual MG content (<0.5%), and undetectable DG levels were obtained. Kinematic viscosity measurements (40 °C) confirmed the high transesterification yield, as the viscosity of palm kernel oil decreased from 30.13 mm2s−1 to <4 mm2s−1.

Comparison of Response Surface Methodology (RSM) and Artificial Neural Network (ANN) in modelling of waste coconut oil ethyl esters production

ABSTRACTThe attributes of renewability and environmental friendliness have made ethanol a preferable alternative to methanol in the production of biodiesel from lipid feedstocks. For the first time, this study adopted Response Surface Methodology (RSM) and Artificial Neural Network (ANN) to model coconut oil ethyl ester (CNOEE) yield. Transesterification parameters such as reaction temperature and ethanol/coconut oil molar ratio and catalyst dosage were varied. Maximum CNOEE yield of 96.70% was attained at 73 °C reaction temperature, 11.9:1 molar ratio, and catalyst dosage of 1.25 wt. %. The experimental yield was in agreement with the predicted yield. Central Composite Design was adopted to develop the RSM while feed-forward back propagation neural network algorithm was employed for the ANN model. Statistical indices were employed to compare the models. The computed coefficient of determination (R2) of 0.9564, root-mean-squarce-error (RMSE) of 0.72739, standard error of prediction (SEP) of 0.008021, mean average error (MAE) of 0.612, and average absolute deviation (AAD) of 0.674901 for RSM model compared to those of R2 (0.9980), RMSE (0.68615), SEP (0.007567), MAE (0.325), and AAD (0.3877) for ANN indicated the superiority of the ANN model over the RSM model. The key fuel properties of the CNOEE met with those of biodiesel international standards.

Using SVM-RSM and ELM-RSM Approaches for Optimizing the Production Process of Methyl and Ethyl Esters

The production of a desired product needs an effective use of the experimental model. The present study proposes an extreme learning machine (ELM) and a support vector machine (SVM) integrated with the response surface methodology (RSM) to solve the complexity in optimization and prediction of the ethyl ester and methyl ester production process. The novel hybrid models of ELM-RSM and ELM-SVM are further used as a case study to estimate the yield of methyl and ethyl esters through a trans-esterification process from waste cooking oil (WCO) based on American Society for Testing and Materials (ASTM) standards. The results of the prediction phase were also compared with artificial neural networks (ANNs) and adaptive neuro-fuzzy inference system (ANFIS), which were recently developed by the second author of this study. Based on the results, an ELM with a correlation coefficient of 0.9815 and 0.9863 for methyl and ethyl esters, respectively, had a high estimation capability compared with that for SVM, ANNs, and ANFIS. Accordingly, the maximum production yield was obtained in the case of using ELM-RSM of 96.86% for ethyl ester at a temperature of 68.48 °C, a catalyst value of 1.15 wt. %, mixing intensity of 650.07 rpm, and an alcohol to oil molar ratio (A/O) of 5.77; for methyl ester, the production yield was 98.46% at a temperature of 67.62 °C, a catalyst value of 1.1 wt. %, mixing intensity of 709.42 rpm, and an A/O of 6.09. Therefore, ELM-RSM increased the production yield by 3.6% for ethyl ester and 3.1% for methyl ester, compared with those for the experimental data.

Synthesis and optimization of ethyl esters from fish oil waste for biodiesel production

Abstract Fish oil is a sustainable, abundant, and low-cost raw material, as it is extracted from fish processing waste. This work suggests that fish oil is appropriate for biodiesel production and evaluates its potential through ethyl esters (EE). Initially, fish oil showed an acid value of 10.86 ± 0.05 mg KOH g−1. But after a neutralization reaction, the acid value was reduced to 0.68 ± 0.01 mg KOH g−1. Alkaline transesterification reactions were performed on a laboratory scale, using a central composite rotational design with three variables and a triplicate over the center point. We studied the appropriate concentrations of ethanol and catalysts, and the temperature that provide the best EE yield. The results showed the optimal condition is with 0.7% of a NaOH catalyst, a temperature of 54 °C, and an ethanol:oil molar ratio of 11.7:1. In such conditions, it was possible to acquire an EE yield of 96.4% with a low acid value of 0.32 ± 0.08 mg KOH g−1, which presented physicochemical properties consistent with the parameters by the Petroleum National Agency's (ANP). In the conditions studied, the results showed high levels of EE from the residual fish oil. This suggests that this raw material, rich in unsaturated fatty acid, can be beneficial for biodiesel.

Transesterification of castor oil to biodiesel using NaY zeolite-supported La2O3 catalysts

As the requirements for green and industrial production of biodiesel increase, recyclable mesoporous spherical catalysts need to be developed. To achieve this, La2O3/NaY spherical particle (3–5 mm) heterogeneous catalysts were prepared by a granulating machine for the production of castor oil biodiesel. The effects of calcination temperature on catalytic activity and crushing strength were investigated. The structure, composition and morphology of the La2O3/NaY were characterized by SEM-EDS, XRD and BET analyses. The effects of calcination temperature, catalyst concentration, ethanol/oil molar ratio, reaction temperature and time on the yield of fatty acid ethyl ester (FAEE) were optimized by single-factor analysis. The addition of surfactant has a positive effect on the La2O3 dispersion and pore size of zeolite NaY. The synthesized catalyst shows excellent reusability and crushing strength which are essential for industrial practices. Under the optimization conditions of catalyst concentration 10 wt%, molar ratio of ethanol to oil 15:1, reaction temperature 70 °C for 50 min, the FAEE yield of 84.6% was obtained.

Effects of a combination of lipases immobilised on desilicated and thiol-modified ZSM-5 for the synthesis of ethyl esters from macauba pulp oil in a solvent-free system

Lipases from Thermomyces lanuginosus (TLL) and Burkholderia cepacia (BCL) were immobilised on desilicated and thiol-modified ZSM-5 via covalent binding. These biocatalysts were tested, both alone and combined, in a reaction for the production of fatty acid ethyl esters from macauba pulp oil. A higher yield of esters was obtained with TLL combined with BCL, and the synergic effect was investigated systematically. Under the best conditions for the reaction, using a mixture of lipases (1% water content, 3:1 M ratio of ethanol to oil, at 30°C), the yield of ethyl esters was 93.1% ± 1.4% over48 h. The mixed lipases could be used in six operation cycles with a retained relative activity of higher than 60%. The combined biocatalysts were also evaluated using reactions carried out with macauba pulp oils with lower free fatty acid content, resulting in lower yields than those obtained with the initial oil.

Palm ethyl ester purification by using Choline Chloride – 1,2 propanediol as deep eutectic solvent

Deep eutectic solvent (DES) has gained more attention for using in biodiesel production because of environmental benefits and process improvements. This study was aimed to test the potency and effectiveness of Deep Eutectic Solvent (DES) based choline chloride: 1.2-propanediol as co-solvent in biodiesel purification. The method used in preparing DES synthesis process was conducted by mixing choline chloride: 1.2-propanediol with mole ratio variation such as: 1:2 ; 1:2.5 ; 1:3 ; and 1:3.5 (mole/mole). The temperature of DES synthesis was at 80 °C with 300 rpm stirring speed for 60 minutes. Variation of DES concentration base on percentage palm oil used: 1, 3, and 5 %. DES possible to increase the ethyl ester yield of biodiesel in the purification process. The best result of yield was 89.95% with the 9:1 molar ratio ethanol: oil and 5% of DES. The operation condition was at 70 °C of temperature reaction, 400 rpm of stirring speed, and 90 minutes of reaction time.

Biodiesel production by ethanolysis of palm oil using SrO as a basic heterogeneous catalyst

In this study, SrO was used as a solid catalyst for simple conversion of palm oil to biodiesel production via the ethanolysis reaction. This catalyst has a high basic strength (H_) and a total basic site of about 3725 μmol/g. The results showed that under optimum reaction conditions at catalyst loading amount of 5 wt.%, ethanol/oil molar ratio of 12:1 and reaction temperature 80 °C; 98.2% yield of fatty acid ethyl ester (FAEE or biodiesel) could be achieved in 3 h. The SrO catalyst can be reused for at least 5 times with excellent catalytic activity without regeneration or treatment. The obtained biodiesel product after purification and treatment process shows high quality fuel properties according to ASTM D6751 and EN 14214 standards for bio-auto fuels. The results indicated that transesterification of palm oil with ethanol using SrO as a basic heterogeneous catalyst is a commercially viable way for biodiesel production in the industrial scale.

Organic solvent extraction-assisted catalytic hydrothermal liquefaction of algae to bio-oil.

In this paper, we report our investigation into a two-step method of transformation of algae to bio-oil. Elemental analysis, gas chromatography-mass spectrometry and Fourier transform infrared spectroscopy were used to analyze bio-oil. First, organic solvent Soxhlet extraction and reflux extraction were used in the algal extraction step. Ethanol was proven to be the best solvent, and the addition of MgSO4 could transform acids to esters. In MgSO4 extraction oil, the yield of hexadecanoic acid ethyl ester was as high as 48.40%. Then, the residual algae powders through the catalytic hydrothermal liquefaction process were converted to bio-oil. Commercialized noble metal catalysts Pd/C, Pt/C, Ru/C and Rh/C combined with Pd/HZSM-5 were used in the second step. Rh/C performed the best in the catalytic hydrothermal liquefaction process, and the highest bio-oil yield of 50.98% and HHV of 30.67 MJ kg−1 were achieved. The oil yield through two steps was higher than that by a direct decomposition step. Also, the two-step method could achieve a higher energy conversion ratio of 85.61% and total energy of 81.09 kJ.

Solvo-thermal in situ transesterification of wet spent coffee grounds for the production of biodiesel

This work addresses non-catalytic biodiesel production from spent coffee ground (SCG) by integrating solvo-thermal effect of 1,2-dichloroethane (DCE) with in situ transesterification over 160 °C. The SCG water content has a positive effect on the DCE hydrolysis up to 60 wt% due to the bimolecular substitution mechanism. The hydrolysis gives an acidic environment favorable for cellulose decomposition, SCG particle size reduction and lipid conversion. The optimal fatty acid ethyl ester yield was 11.8 wt% based on the mass of dried SCG with 3.36 ml ethanol and 3.16 ml DCE at 196.8 °C through the response surface methodology. Using the solvo-thermal effect, direct utilization of wet SCG as a biodiesel feedstock provides not only economic feasibility without using drying process and additional acid catalyst but also environmental advantage of recycling the municipal waste.

Solvent-Free Biodiesel Production Catalyzed by Crude Lipase Powder from Seeds: Effects of Alcohol Polarity, Glycerol, and Thermodynamic Water Activity.

The aim of this work was to evaluate the potential of crude lipase powders made from Adansonia grandidieri and Jatropha mahafalensis seeds for the synthesis of fatty acid alkyl esters in a solvent-free system. The influence of the nature of the alcohol, the amount of glycerol, and hydration of the powder was investigated. Results showed that the activity of these crude lipase powders was inversely proportional to the alcohol polarity and the amount of the glycerol in the reaction medium. To ensure optimum activity, A. grandidieri and J. mahafalensis powders must be conditioned to a water activity of 0.33 and 0.66. To obtain a fatty acid ethyl ester yield greater than 95% with A. grandidieri, ethanol should be introduced at an amount corresponding to a triacylglycerol to ethanol molar ratio of 2:1 every 15 h for 96 h and use 25% of preconditioned crude lipase powders (2 additions of 12.5%).

Tungsten supported Ti/SiO2 nanoflowers as reusable heterogeneous catalyst for biodiesel production

Abstract Present work demonstrates an easy route by sol-gel method, without using any template, for the synthesis of flower shaped tungsten (W) supported TiO2/SiO2catalyst for the triglyceride transesterification. The structure of the catalyst was established by powder X-ray diffraction and surface morphology and particle size by field emission scanning and high resolution transmission electron microscopy studies, respectively. The oxidation state of tungsten by X-ray photoelectron spectroscopy was found to be +6. Under the optimized reaction conditions of 5 wt% of 20-W/TiO2/SiO2-700 catalyst, 30:1 methanol to oil molar ratio and 65 °C reaction temperature, more than 98% fatty acid ethyl ester yield was obtained in 4 h. The kinetic and thermodynamic parameter of the reaction was also evaluated following the pseudo-first order equation. The catalyst was recycled in four consecutive runs and total metal contents in biodiesel was observed

Biodiesel production from lignocellulosic biomass

Alkaline transesterification of Silybum marianum seed oil to biodiesel using methanol and ethanol was studied. The two methods used were conventional stirring (600 rpm) and ultrasonication (40 kHz). Oil was extracted from the seeds, followed by physico-chemical properties' determination and transesterification to biodiesel. The seeds contained 46% oil which had low free fatty acids (FFA) (0.68%). Linoleic acid (65.68%) was the main composition of the oil. Ultrasonication transesterification with methanol gave the highest yield (95.75%) after 20 min. Yields of methyl esters were higher than respective yields of ethyl esters. Using first order reaction kinetics model, the reaction rate constants were 2.3 × 10− 2 s− 1 and 7.0 × 10− 3 s− 1 for ultrasonication using methanol and ethanol, respectively. With the exception of oxidative stability (2.1 h) and iodine values (132-methyl and 133-ethyl esters), properties out of range but can easily be improved, the remaining properties including cetane number, flash point and the cold flow ones of both methyl and ethyl esters were similar and comparable to Chinese, ASTM and European Union standards. The findings of this study complement with the abundance of S. marianum oil at cultivation and silymarin industrial production as by-product indicates its potentially new non-edible feedstock for biodiesel.

Combined Use of a Two-Stage Packed Bed Reactor with a Glycerol Extraction Column for Enzymatic Biodiesel Synthesis from Macaw Palm Oil

Biodiesel production by ethanolysis of macaw palm oil mediated by Burkholderia cepacia lipase immobilized on SiO2-PVA was assessed in packed bed reactors (PBRs). Reactors with different height-to-diameter ratios (l/d) were used for continuous runs carried out using an oil-to-ethanol molar ratio of 1:12 at a fixed space-time (14 h). The best performance was attained by using reactor with an l/d of 15, which was further used to perform runs with different space-times in a two-stage PBR by incorporating a column with cationic resin for removing the glycerol formed as byproduct. The system operation for a space-time of 16 h resulted in a productivity of 37.9 ± 2.4 mgester·gmedium–1·h–1 (ethyl esters yield = 96.3 ± 2.1%). Efficient glycerol removal helped the biocatalyst stability, with a half-life (t1/2) of 1512 h. The results demonstrate that a continuous enzymatic production of biodiesel from macaw palm oil can generate high yield in a two-stage PBR system incorporating a glycerol extraction column.

Biodiesel production from Jatropha curcas L. oil by simultaneous esterification and transesterification using sulphated zirconia

Ethyl esters were synthesized by simultaneous esterification and transesterification reactions, using Jatropha curcas L. oil as raw material and sulphated zirconia (SZ) as catalyst. SZ catalysts were synthesized by the precipitation method, and the final pH of each precipitation was 6, 7 and 8 (SZ6, SZ7 and SZ8, respectively). X-ray diffraction showed the presence and intensity of a tetragonal crystal phase, which was associated with acidity and activity of the catalysts. In addition, the BET surface area was directly proportional to the pH of precipitation. During the catalytic tests it was observed that the most acidic sample (SZ8) had the highest catalytic activity for simultaneous esterification and transesterification, resulting in a 59.4% yield of ethyl esters. Furthermore, the catalyst had activity for separate esterification and transesterification reactions, and both were influenced by the mechanism of the simultaneous reactions. It could also be seen that, in reactions at different acidity levels, free fatty acids influenced the reaction mechanism, such that for high acid contents (14.29%), higher ethyl ester yields and faster reaction rates were obtained compared with lower acid contents (2.39%).

Continuous enzymatic biodiesel production from coconut oil in two-stage packed-bed reactor incorporating an extracting column to remove glycerol formed as by-product.

The transesterification of coconut oil with ethanol catalyzed by Burkholderia cepacia lipase immobilized on polysiloxane-polyvinyl alcohol was performed in a continuous flow. The experimental design consisted of a two-stage packed-bed reactor incorporating a column with cationic resin (Lewatit GF 202) to remove the glycerol formed as by-product and the reactor performance was quantified for three different flow rates corresponding to space-times from 10 to 14h. The influence of space-time on the ethyl ester (FAEE) concentrations, yields and productivities was determined. The reactor operation was demonstrated for space-time of 14h attaining FAEE concentrations of 58.5±0.87wt%, FAEE yields of 97.3±1.9% and productivities of 41.6 ±1.0mgesterg medium (-1) h(-1). Biodiesel purified samples showed average kinematic viscosity values of 5.5±0.3mm(2)s(-1) that meet the criteria established by the American National Standard ASTM (D6751). The immobilized lipase was found to be stable regarding its morphological and catalytic characteristics, showing half-life time (t 1/2) around 1540h. The continuous packed-bed reactor connected in series with simultaneous glycerol removal has a great potential to attain high level of transesterification yields, raising biodiesel productivity.