Esterification For Biodiesel Production Research Articles

ZrO2-based catalysts for biodiesel production: A review

ZrO2-based catalysts are remarkable catalyst with unique advantageous in transesterification and esterification for biodiesel production. Various modifications have been conducted refer to a specified surface properties consist of surface acidity/basicity, specific surface area and porosity, hydrophobicity, and catalysts stability. Summary on the basic concept on catalyst synthesis, applicability for various feedstocks along with their reusability aspect in biodiesel production are discussed in this review. Even though the activity of the catalyst is depending on many factors including the oil feedstocks, reaction temperature, molar ratio of oil to methanol, and other conditions, the controllable surface properties of catalyst is a benefit of ZrO2-based catalysts. The recyclability and reusability of the catalyst become important aspect for developing a sustainable biodiesel production in the perspective of green chemistry. In addition, future perspective to make sure the applicability of the catalyst for a sustainable process by life cycle assessment is highlighted in this review.

Characterization of rare earths obtained from monazite concentrate processing and their application in esterification for biodiesel production

Rare earths namely lanthanum (La), neodymium (Nd) and cerium (Ce) obtained from the monazite concentrate processing were comprehensively characterized using XRF, XRD, FTIR, N2 adsorption–desorption, CO2/NH3-TPD and SEM to reveal their catalytic performance in esterification of oleic acid for biodiesel production. The effect of calcination temperatures (500–1000 °C) on the catalyst properties and biodiesel conversion was also investigated. The catalytic performances of the catalysts were tested under the conditions of catalyst loading 3 wt%, molar ratio of oil to methanol 1:20, reaction temperature 200 °C, stirring rate 600 rpm for 5 h. It is interesting that the Ce catalyst calcined at 1000 °C showed the best performance and the highest FAME content of 78.54% could be achieved, even its acid sites was very low, which is probably associated to the availability of oxygen vacancies at high calcination temperature. The La catalysts calcined at 600 °C exhibited the balancing of strong Lewis acid and Lewis basic sites, which is related to the catalytic activity with FAME content of 74.44%. For the catalytic performance of Nd catalysts, the FAME content of 63.60% was obtained at calcination temperature of 500 °C, which was lower than those La and Ce catalysts.

Characterization of Rare Earths Obtained from Monazite Concentrate Processing and Their Application in Esterification for Biodiesel Production

Characterization of Rare Earths Obtained from Monazite Concentrate Processing and Their Application in Esterification for Biodiesel Production

Esterification for biodiesel production with a phantom catalyst: Bubble mediated reactive distillation

The initial aim of the paper is to dramatically improve the pretreatment stage of biodiesel production, which converts problematic free fatty acids to fatty acid methyl esters, by introduction of a microbubble mediated reactive distillation stage instead of acid pretreatment. This will shift the conventional esterification process towards completion with a yield higher than 80%, even without high excess methanol. Application of ozone microbubbles has the advantage over acid gas catalysis in that it gives higher conversion and leaves no catalyst residue and requires no further catalyst recovery separation steps (a “phantom” catalyst). Unreacted ozone breaks down into oxygen, so the off-gases are just a humid air stream that can be vented. Importantly, ozonolysis breaks carbon–carbon double bonds into aldehydes and carboxylic acids. Many ester species were found after contacting the feedstock with ozone-rich microbubbles, depending on the molecular structure of the alcohols for the ozonolysis of oleic acid with alcohols, i.e., methanol, ethanol, n-propanol, iso-propanol, and n-butanol. In the case of ozonolysis of used cooking oil mixed with methanol, the results from the GC–MS show that all saturated free fatty acids (including palmitic acid, stearic acid, and myristic acid) are converted to methyl esters within 20 h of 60 °C ozonolysis, whereas trace amounts of these chemicals remain at lower temperatures. The results also show that the conversion of oleic acid to form oleic acid methyl ester is 91.16% after 32 h of ozonolysis at 60 °C. Therefore, the free fatty acid content in used cooking oil is less than 1.33%, which makes it suitable as a reactant for biodiesel production via transesterification. However, this result is different from the result provided by ASTM D974 in that the acid numbers decrease dramatically by 25% at the beginning of ozonolysis followed by a plateau. Moreover, if the fluidic oscillator is used to generate bubbles in ozonolysis of oleic acid mixed with methanol, the results show that the yields of ozonolysis product 1-nonanal increase by 30%. This observation means that ozonolysis of oleic acid is relative to the specific interfacial area, and favoured at low liquid temperatures.

Deacidification process of crude inedible plant oil by esterification for biodiesel production

A process to deacidify crude plant oil by the esterification of free fatty acid with methanol was studied. A reaction model in a heterogeneous system was developed, and the equilibrium and rate constants of the esterification reaction were measured experimentally using a standard type of stirred vessel. In this measurement range, the liquid-liquid dispersion in the stirred bessel was oil-in-water type. The equilibrium constant of esterification was relatively small, confirming high methanol concentration should be required to attain high conversion of free fatty acid. An esterification process was then suggested wherein a countercurrent reactor system was employed, and deacidification to treat model crude plant oils was simulated numerically. In the cases of reaction equilibrium conditions, the molar flow rate ratio of methanol relative to the feed oil required to satisfy the specification of free fatty acid in the treated feed oil decreased as the total stage number increased. The molar flow rate ratio was reduced from 7.5 with single stage reactor to 1.1 with two-stage reactor. Then, the two-stage countercurrent reactor was effective enough for decreasing the molar flow rate ratio to meet the specification. Simulating the treatment of model crud Jatropha oil by esterification using stirred vessel considering the effects of reaction rates showed that the suggested process could sufficiently reduce the content of free fatty acid with reasonable methanol flow rate and reactor volume.

Process Optimization of Ethyl Ester Biodiesel Production from Used Vegetable Oil under Sodium Methoxide Catalyst and its Purification by Ion Exchange Resin

Production of ethyl ester biodiesel from a tranesterification reaction of used vegetable oil and ethanol was carried out using a sodium methoxide catalyst. Response surface methodology (RSM) was applied to investigate the effect of experimental factors on the fatty acid ethyl ester (FAEE) conversion. The design of the experiment involved a 5-level-4-factor central composite design and 30 runs were used to achieve the optimum percentage FAEE conversion that was determined by 1H-NMR. The coefficient of determination (R2) for the regression equation was 86.49% and the probability value (p<0.05) demonstrated a very good fit for the regression model. The optimum conditions obtained from RSM were 4% v/v of catalyst, 35.61% v/v of ethanol-to-oil, at 43.70°C reaction temperature, and 75.45 min of reaction time. The produced ethyl ester biodiesel was further purified by wet washing compared with dry washing using ion exchange resin. The result showed that the purified biodiesel by wet washing met the EN standard but the dry washing out put did not but only for the acid value. The blending of 10% v/v of purified biodiesel obtained from dry washing with 90% v/v of petrodiesel could decrease the acid value to meet the EN standard.

Mesoporous Al–Mo Oxides as an Effective and Stable Catalyst for the Synthesis of Biodiesel from the Esterification of Free-Fatty Acids in Non-edible Oils

A kind of mesoporous Al–Mo mixed oxides as solid acid catalysts was designed and prepared through a facile and low-cost approach using stearic acid as a soft modifier, and investigated by X-ray diffraction, thermogravimetric, fourier transform infrared spectra, N2 adsorption–desorption, ammonia temperature programmed desorption and scanning electron microscopy. By using this catalyst, an environmentally benign process for esterification of free-fatty acids in non-edible Euphorbia lathyris crude oil with methanol was developed. It was shown that the activity of the catalysts for the esterification reaction is closely related to their mesoporous structures, surface area and acid properties. The Al–Mo solid acid catalyst exhibited an optimal esterification performance with 80.9% esterification efficiency under the optimum synthesis conditions. Moreover, the conversion remained over 73.2% after the catalyst being used for three times. These results showed that the catalysts have promising viability in esterification for biodiesel production in industry. Mesoporous Al–Mo oxides catalysts were prepared via a facile and low-cost modified approach and exhibited excellent catalytic activity and reusability in esterification reaction of high value acid non-edible oil and methanol. This material has great potential in the future production of biofuels used as the solid acid catalyst.

Synthesis and Sulfating of the ZrO<sub>2</sub> for Obtaining of a Catalyst in Order to Future Use in Esterification for Biodiesel Production

This work aims to synthesize ZrO2by the combustion reaction method and its sulfating for future use as a catalyst in esterification of the cottonseed oil. The synthesized sample was produced in batches of 15g, using as precursor the zirconium IV n-propoxide and urea as fuel. The sulfating occurred with an ion content of SO4-2with 30% in relation to the mass of ZrO2. The samples were characterized by XRD, SEM and particle size distribution. The results revealed the formation of the monoclinic majority phase with traces of the orthorhombic phase referring to the synthesized sample, and a transformation of the orthorhombic phase to the tetragonal phase when sulfated. The morphology have shown the formation of homogeneous and spherical agglomerates, with a mean particle size of 24.34nm. The presence of traces of the tetragonal phase in the XRD of the SO42-/ZrO2was a great indicator for future use in the esterification reaction to obtain biodiesel, because this type of phase after sulfating becomes very promising for the ester obtaining.

Free Lipase‐Catalyzed Esterification of Oleic Acid for Fatty Acid Ethyl Ester Preparation with Response Surface Optimization

AbstractFree lipase‐mediated alcoholysis for biodiesel production has drawn increasing attention in recent years due to its advantages of lower cost and faster reaction rate compared to immobilized lipase. Ethanol, derived from renewable biomass, has a great potential for biodiesel production. A previous study showed that free lipase NS81006 could effectively catalyze the ethanolysis of triglycerides for biodiesel preparation. Since most crude plant oils always contain an amount of free fatty acids, oleic acid was used as the model substrate for this study on lipase‐mediated esterification for biodiesel production. The central composite design of the response surface methodology was adopted for process optimization. A biodiesel yield of over 90 % was achieved under optimal reaction conditions and the repeated use of the free lipase was easily realized through phase separation either by natural gravity force or centrifugation.

Simultaneous transesterification and esterification for biodiesel production with and without a sulphated zirconia catalyst

Simultaneous catalysed transesterification of rapeseed oil and esterification of 10wt% myristic acid with methanol was studied using sulphated zirconia and in the absence of catalyst. The maximum total FAME content of 86% was obtained at a catalyst loading of 3wt%, temperature of 170°C, pressure of 22 bars, molar ratio of oil to methanol of 1:20 and stirring rate of 600rpm for 60min. At these conditions, FFA was observed to reach 2.95% (2.94mg/ml sol.). Thermo/catalytic cracking and hydrolysis of triglyceride was presumed to form the FFA. Water was also formed: dehydration of methanol is likely to be the principal source. Three sets of main reactions occurred at distinctly different rates. Esterification of myristic acid was the most rapid reaction. Direct transesterification of triglyceride and side-reactions of thermo/catalytic cracking of triglyceride followed by esterification of fatty acid and hydrolysis of triglyceride followed by esterification of fatty acid occurred afterward. Dehydration of methanol was observed throughout the reaction, producing a constant supply of water, thereby facilitating hydrolysis reactions.

Production of Biodiesel from High Acid Value Waste Cooking Oil Using an Optimized Lipase Enzyme/Acid‐Catalyzed Hybrid Process

The present study is aimed at developing an enzymatic/acid‐catalyzed hybrid process for biodiesel production using waste cooking oil with high acid value (poor quality) as feedstock. Tuned enzyme was prepared using a rapid drying technique of microwave dehydration (time required around 15 minutes). Further enhancement was achieved by three phase partitioning (TPP) method. The results on the lipase enzyme which was subjected to pH tuning and TPP, indicated remarkable increase in the initial rate of transesterification by 3.8 times. Microwave irradiation was found to increase the initial reaction rates by further 1.6 times, hence giving a combined increase in activity of about 5.4 times. The optimized enzyme was used for hydrolysis and 88% of the oil taken initially was hydrolyzed by the lipase. The hydrolysate was further used in acid‐catalyzed esterification for biodiesel production. By using a feedstock to methanol molar ratio of 1:15 and a sulphuric acid concentration of 2.5%, a biodiesel conversion of 88% was obtained at 50 °C for an hour reaction time. This hybrid process may open a way for biodiesel production using unrefined and used oil with high acid value as feedstock.