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Modelling the effect of reaction time, catalyst concentration, and oil-to-methanol ratio on the waste cooking oil biodiesel was studied using response surface methodology. Biodiesel was made using three different heterogeneous catalysts. Analysis showed catalysts 2 and 3 to be significant in transesterification. However, all catalysts had second-degree significance for esterification yield. For catalysts 1 and 2 there was a clear interaction between catalyst concentration and oil-to-methanol ratio. Clear interaction was also noticed between reaction time and oil-to-methanol ratio for all catalysts. There was moderate to no interaction between the effects of time and catalyst concentrations for all catalysts. The best yield was found at lower oil-to-methanol ratios (nearly 0.02) and higher catalyst concentrations (at 10%). Reaction times close to 7 hours for catalyst 1 and close to 5 for the other catalysts were the optimum values for best yield and lowest acid value. [ABSTRACT FROM AUTHOR]

The current research proposed the work on the consumption of waste cooking oil (WCO) as a valuable resource for the production of biodiesel. This study focuses on maximizing output yield by employing composite heterogeneous catalysts, namely calcinated calcium oxide with aluminum oxide (CaO/Al2O3) and calcium oxide with titanium oxide (CaO/TiO2). The calcination process was adopted for the catalysts at 600°C for 5 h to improve catalytic activities and to increase surface area. XRD and TGA were implemented to analyze the crystal structure and thermal stability of these heterogeneous catalysts. Experimentation was planned by implementing the response surface methodology (RSM) approach in combination with the BoxBehnken design. The optimum yield of fatty acid methyl esters (FAMEs) was experimentally observed at 96.56%, using CaO/Al2O3 at methanol to oil (m/o) molar ratio of 11.9:1, 3.19% catalyst loading, 53.79°C and 76.86 minutes (min). The maximum experimental yield with CaO/TiO2 was observed at 98.15% with the optimized operating conditions of independent process variables viz. m/o molar ratio 11:99, 2.53 wt.% catalyst loading and 68.14 min at 59.79°C. The research recommends the potential use of WCO and both the heterogeneous catalysts for optimal biodiesel yield; however, CaO/TiO2 exhibits superior performance over CaO/Al2O3, which is also confirmed by the XRD and TGA results. [ABSTRACT FROM AUTHOR]

The leaching and reusability problem of the catalyst in the catalytic transesterification for biodiesel production led to the poor sustainability and high posttreatment cost. Herein, a reusable magnetic Ca2Fe2O5/CaO@MgFe2O4-Fe2O3 catalyst with high textural stability and good catalytic activity was prepared in this study, and its catalytic performance toward transesterification of five different oil feedstocks was evaluated. Catalyst preparation conditions were optimized and characterizations including scanning electron microscope (SEM), X-ray diffraction analysis (XRD), and so on, were also conducted to investigate the catalytic behaviors. The results demonstrated that the catalyst has good ferromagnetism for magnetic separation, and the presence of synergistic interaction enhanced catalytic activity with all of > 90% biodiesel yield and improved the reusability with > 75% biodiesel yields at the 10th cycle. In addition, the biodiesel yield reached the maximum under the transesterification reaction parameters were optimized, and at the 15/1 methanol/oil molar ratio, 2.5 wt% catalyst dosage, 70°C for 120 min. Further, for biodiesel from five different oil feedstocks, the same composition, all of > 90% yield and the quality that met the American Society of Testing Materials (ASTM) standards demonstrated the strong oil feedstocks applicability and application potential of catalysts. [ABSTRACT FROM AUTHOR]

Heterogeneous basic catalysts, namely calcium oxide, are referred to as promising catalysts for biodiesel (FAME, fatty acid methyl esters) production since they can be easily separated from the reaction medium allowing them to operate in a continuous mode. Despite the relatively high catalytic activity of calcium catalysts, they present slower alcoholysis rates than homogeneous conventional catalysts (sodium or potassium methanoate). In order to improve the catalytic activity, CaO-based catalysts, modified with alkali elements (Li, Cs, Sr, and Mg) were prepared. Dopant element contents of 10% and 30%, as weight basis (5–50% molar), were introduced by wet impregnation using aqueous solutions of nitrate salts. The effect of calcination temperature (575°C and 800°C) on both activity and stability was studied. All the prepared catalysts, raw and alkali modified, showed pKa<15.0 when characterized by Hammett indicators in methanolic solution. Such basicity is characteristic of Ca hydroxide, thus indicating that the catalysts surfaces were covered with Ca-OH species. FAME yield, in soybean oil methanolysis, higher than 96% was obtained for the first batch reaction for all the tested catalysts showing that alkali dopants have an almost nihil effect on the catalysts performances. The deactivation tests performed with catalysts without intermediate reactivation showed that calcination temperature plays a major role in stability as it enhances the formation of calcium diglyceroxide. The presence of Ca hydroxide in fresh catalysts appears to be responsible for fast deactivation. The dopant elements prompt the catalysts deactivation. Catalysts calcined at higher temperatures showed slower deactivation, which can be due to the formation of larger particles, thus reducing the contact with the formed glycerin. Alkali dopants enhanced the CaO sintering for the highest calcination temperature. Calcium diglyceroxide formed during the reaction is responsible for deactivating the catalyst, due to leaching, and such effect is prompted by alkali dopants. [ABSTRACT FROM AUTHOR]

Literature on biodiesel production over the last 10 years (2007–2018) has been critically reviewed directing further research toward membrane-based sustainable and green production. The manuscript discusses how biodiesel production strategies have evolved in the recent years through adoption of better feedstock, better catalysts, more efficient reactor technology, and through incorporation of more efficient downstream separation-purification techniques. The review reveals that though transesterification reaction between alcohol and plant oil/animal fats leading to production of biodiesel is simple, the downstream separation and purification of the final product (fatty acid methyl esters) is quite challenging. This review shows that productivity can be enhanced through new generation catalysts, use of green solvents, and a more efficient reactor technology while the use of tailor-made membrane in appropriate modules holds the promise of low-cost and eco-friendly downstream purification. It is exposed that a membrane-based technology can bring about high degree of process intensification, whereas recovery and reuse of catalysts and alcohol are likely to add to the economy of the process, resulting in sustainable production technology. [ABSTRACT FROM AUTHOR]

The naphthenic acids (NAs) present in the crude oil can lead to the corrosion problems in oil refinery equipment apart from reduces the performances of the oil. In this study, the method to remove NA were done by means of extraction using sodium thiocyanate in ethanol with the aid of Ni/Ca/Al2O3 and Ni/Ce/Al2O3 catalysts at 27 °C reaction temperature. The catalyst was prepared by incipient wetness impregnation method (IWI) and calcined at three different temperature, 800, 900 and 1000 °C respectively. The efficiency of the extraction was affected by the catalyst calcination temperature. Both catalysts calcined at 800 and 900 °C gave total acid number (TAN) value more than 1 mg KOH/g while by using Ni/Ca(10:90)/Al2O3 and Ni/Ce(10:90)/Al2O3 calcined at 1000 °C the TAN value were reduced to 0.28 and 0.65 mg KOH/g respectively. Brunauer-Emmett Teller (BET) result shows both catalysts have large surface area that provide more reaction cites when calcined at 1000 °C. X-ray Diffraction Spectroscopy (XRD) analysis of Ni/Ca/Al2O3 catalyst revealed that the active site was dominated by the Al2O3 species while CeO2 was the active site for Ni/Ce/Al2O3 catalyst. In conclusion, both catalysts reduced the TAN value of acidic crude oil efficiently. [ABSTRACT FROM AUTHOR]