In situ synthesis and characterization of Ca-Mg-Al hydrotalcite on ceramic membrane for biodiesel production☆

In situ surface synthesis of Ca–Mg–Al hydrotalcite (HT) on inorganic ceramic membrane (CM) was investigated with urea as precipitator. The effects of molar ratio of raw materials, crystallization time, and temperature on surface synthesis of HT were examined. The as-prepared HT/CM samples were characterized by XRD and SEM and an in sit growth mechanismof HT on CMwas proposed. KF/HT/CMobtained by loading potassium fluoride (KF) on the HT layer by impregnation and calcination method was used as catalyst for transesterification between palm oil and methanol. The comparison of KF/HT/CMand pure KF/HT powder under identical reaction conditions shows that the production of fatty acid methyl ester is equivalent, which means that the use of inorganic catalytic membrane in the transesterification is a viable alternative.     

Catalytic properties of a lipase from Photobacterium lipolyticum for biodiesel production containing a high methanol concentration

Biodiesel, an alternative fuel, is generated via the transesterification reaction of vegetable oil or animal oil with alcohol. Currently, many reports have noted that microbial lipases might be utilized for the production of biodiesel. Among them, immobilized Candida antarctica lipase B (Novozym435) is frequently utilized for its biocatalytic efficiency and availability. However, as the enzyme is unstable in a medium containing high concentrations of methanol, a multi-stepwise methanol supply is required for the efficient production of biodiesel. Photobacterium lipolyticum lipase (M37) was determined to be quite stable in a medium containing a high concentration of methanol. The enzyme activity was maintained for longer than 48 h without any loss at a methanol concentration of 10%. In an effort to evaluate enzyme performance in the production of biodiesel, we have compared M37 lipase and Novozym435 in the biodiesel production reaction using fresh or waste oil and methanol. In the 3-stepwise methanol feeding method generally conducted for Novozym435 in biodiesel production, the M37 lipase showed a similar or superior conversion yield to Novozym435. However, the M37 lipase evidenced significantly higher conversion yields in the 2 and 1 step methanol feeding reactions. Particularly in the 1 step process using 10% of methanol where almost no conversion was detected by Novozym435, the biodiesel yield achieved with M37 lipase reached a level of up to 70% of the possible maximum yield. Consequently, this methanol-tolerant lipase, M37, has been shown to be a suitable enzyme for use in the biodiesel production process.     

Biodiesel production by ultrasound-assisted transesterification: State of the art and the perspectives

In the present paper state-of-the art and perspectives of ultrasound-assisted (UA) biodiesel production from different oil-bearing materials using acid, base and enzyme catalysts are critically discussed. The ultrasound action in biodiesel production is primarily based on the emulsification of the immiscible liquid reactants by microturbulence generated by radial motion of cavitation bubbles and the physical changes on the surface texture of the solid catalysts generating new active surface area. The importance of ultrasound characteristics and other process variables for the biodiesel yield and the reaction rate is focused on. UA transesterification is compared with other techniques for biodiesel production. Several different developing methods reducing the biodiesel production costs such as the optimization of process factors, the development of the process kinetic models, the use of phase transfer catalysts, the application of the continuous process, the design of novel types of ultrasonic reactors and the in situ ultrasound application in transesterification of oily feedstocks are also discussed.     

Review and prospects of Jatropha biodiesel industry in China

Jatropha curcas L. is chosen as an ideal biodiesel crop in China because its seed kernel has high oil content (43-61%) and it does not compete with food. Its oil is non-edible, and the trees can resist drought and grow on barren and marginal lands without using arable land. This article reviews the history of Jatropha, current development status and problems in its seeds, propagation, plantation management, oil extraction, biodiesel processing and other value-added products production techniques in China. The commercial production of seed, oil and biodiesel as well as research advancement in China is also introduced and discussed. Examples about our new bred mutant and selected high-oil-yield Jatropha varieties, high-qualified produced biodiesel, and biodiesel pilot plant are presented. Finally, future prospects of Jatropha biodiesel industry in China are discussed.     

Transesterification of rapeseed and palm oils in supercritical methanol and ethanol

The results of the rapeseed and palm oils transesterification with supercritical methanol and ethanol were presented. The studies were performed using the experimental setups which are working in batch and continuous regimes. The effect of reaction conditions (temperature, pressure, oil to alcohol ratio, reaction time) on the biodiesel production (conversion yield) was studied. Also the effect of preliminary ultrasonic treatment (ultrasonic irradiation, emulsification of immiscible oil and alcohol mixture) of the initial reagents (emulsion preparation) on the stage before transesterification reaction conduction on the conversion yield was studied. We found that the preliminary ultrasonic treatment of the initial reagents increases considerably the conversion yield. Optimal technological conditions were determined to be as follows: pressure within 20-30 MPa, temperature within 573-623 K. The optimal values of the oil to alcohol ratio strongly depend on preliminary treatment of the reaction mixture. The study showed that the conversion yield at the same temperature with 96 wt.% of ethanol is higher than with 100 wt.% of methanol.     

Small scale biodiesel synthesis from waste frying oil and crude methanol in Morocco

Biodiesel was produced at small scale by transesterification of used frying oil(UFO) recovered from Moroccan pastry shops and fish frying restaurants. Biodiesel was first synthesised at laboratory scale in order to optimize the transesterification parameters. The cost of the final product was also optimized using low-cost raw materials.The UFO and the produced biodiesel were characterized with several techniques including gas chromatography,1H NMR,13 C NMR, FTIR, and TGA–TDA techniques.1H NMR gas chromatographic analyses of the final product confirmed that the transesterification in the chosen experimental conditions was completed. These results were confirmed by TGA–TDA analysis used as new techniques to monitoring triglyceride conversion. The biodiesel did not contain any trace of glycerol, and it did meet the international standards. The transesterification at low cost in small scale conditions was performed at 60 °C using 1.2% of KOH and a methanol/oil molar ratio of 6:1. A yield of 80.8% was achieved. The properties of the produced biodiesel were found to be as good as those of biodiesels obeying to European standards. The biodiesel production was also performed at small-scale for individual utilisation. Thus, the product was tested in a kerosene stove for heating and non-modified commercial diesel engine producing electricity.     

Development of solid base catalyst X/Y/MgO/γ-Al2O3 for optimization of preparation of biodiesel from Jatropha curcas L.seed oil

The preparation and regeneration conditions of the identified catalyst X/Y/MgO/γ-Al₂O₃ with high catalytic activity were studied and optimized. The biodiesel was prepared by transesterification of Jatropha curcas seed oil produced in Guizhou with methanol at its reflux temoerature in the presence of X/Y/MgO/γ-Al₂O₃. The pilot plant tests were carried out in a 100 L reaction vessel. Both average yield and fatty acid methyl esters (FAME) content reached more than 96.50% under the optimum reaction conditions of the pilot plant tests designed withan oil/methanol molar ratio of 1: 10, catalyst concentration of 1.00%, and reaction time of 3 h at reflux temperature. In addition, analysis shows that the quality of biodiesel meets the standard EN 14214. __________ Translated from Modern Chemical Industry, 2007, 27(Suppl. 2): 452–455 [译自: 现代化工]     

Application of KF/MgO as a heterogeneous catalyst in the production of biodiesel from rapeseed oil

Biodiesel was synthesized from rapeseed oil by transesterification over Magnesium oxide loaded with KF. The catalytic activity strongly depends on the loading amount of KF and calcined temperature. We found that the reaction reached a 79.37% yield when the loading amount was at 35 wt% and calcined at 500 °C. The simply dried 30% KF/MgO at 80 °C was found to give equally good results from the catalyst calcined at 500 °C, avoiding the usual activation at high temperature. The catalysts were characterized by the Hammett indicator method, BET, TG/DTG, XRD, NMR, EDS, and FT-IR. According to the instrumental analysis, the activity in the transesterification probably belonged to coordinately unsaturated F⁻ and liberation of hydroxide during preparation. The effects of methanol/oil ratio and catalyst amounts on the conversion were also studied in this paper.     

Transesterification of sunflower oil over zeolites using different metal loading: A case of leaching and agglomeration studies

The aim of this study was to analyse the catalytic performance of several heterogeneous catalysts in the transesterification of sunflower oil with methanol. In order to characterize the different catalysts, nitrogen adsorption/desorption and CO₂ temperature programmed desorption were used. The transesterification of sunflower oil was carried out using three different zeolites: mordenite, beta and X, to determine the influence of the kind of zeolite on the methyl ester production. The influence of the metal incorporation technique was studied using both impregnation and ion-exchange methods. Also, the transesterification reaction was carried out using catalysts with different metal loading. Finally, zeolite X was agglomerated with a binder, sodium bentonite, to study how the presence of a binder could change the catalytic performance of the zeolite. A methyl ester content of 93.5 and 95.1 wt% was obtained at 60 °C employing zeolite X with or without sodium bentonite, respectively. All biodiesel synthesized were characterized using the standard UNE-EN 14214. A complete deactivation study was carried out in order to check the sodium leaching from the catalyst. The results supported the hypothesis of a homogeneous-like mechanism where the alkali methoxide species were leached out.     

Biodiesel production from mixtures of canola oil and used cooking oil

Used cooking oil (UCO) was mixed with canola oil at various ratios in order to make use of used cooking oil for production of biodiesel and also lower the cost of biodiesel production. Methyl and ethyl esters were prepared by means of KOH-catalyzed transesterification from the mixtures of both the oils. Water content, acid value and viscosity of most esters met ASTM standard except for ethyl esters prepared from used cooking oil. Canola oil content of at least 60% in the used cooking oil/canola oil feedstock is required in order to produce ethyl ester satisfying ASTM specifications. Although ethanolysis was proved to be more challenging, ethyl esters showed reduced crystallization temperature (−45.0 to −54.4 °C) as compared to methyl esters (−35.3 to −43.0 °C). A somewhat better low-temperature property of ester was observed at higher used cooking oil to canola oil ratio in spite of similar fatty acid compositions of both oils.