902 resultados para Biodiesel microemulsion


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The feasibility of biodiesel production from soapstock containing high water content and fatty matters by a solid acid catalyst was investigated. Soapstock was converted to high-acid acid oil (HAAO) by the hydrolysis by KOH and the acidulation by sulfuric acid. The acid value of soapstock-HAAO increased to 199.1 mg KOH/g but a large amount of potassium sulfate was produced. To resolve the formation of potassium sulfate, acid oil was extracted from soapstock and was converted to HAAO by using sodium dodecyl benzene sulfonate (SDBS). The maximum acid value of acid oil-HAAO was 194.2 mg KOH/g when the mass ratio of acid oil, sulfuric acid, and water was 10:4:10 at 2% of SDBS. In the esterification of HAAO using Amberylst-15, fatty acid methyl ester (FAME) concentration was 91.7 and 81.3% for soapstock and acid oil, respectively. After the distillation, FAME concentration became 98.1% and 96.7% for soapstock and acid oil. The distillation process decreased the total glycerin and the acid value of FAME produced a little.

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In this study, the preparations of biodiesel from three different feedstocks, including rapeseed oil, high acidified Chinese wood oil and trap grease, were carried out in a pilot scale of 200 t yr(-1) biodiesel production system. The optimum operating conditions for transesterification of rapeseed oil in plug flow reactor were found to be as follows: the catalyst dosage is 1.2 wt%; the retention time is about 17 min; the bed temperature is 65 degrees C; the oil/methanol ratio is 1:6; the content of methyl ester is 96.33% under these conditions. A kind of ion exchange resin, a solid acid catalyst, filled in the fixed bed reactor was used as the esterification catalyst for the pretreating of high acidified oil. The acid value of Chinese wood oil could be reduced from 7 to 0.8 mg KOH.g(-1) after 88 min, the optimum operating conditions were obtained as follow: molar ratio of methanol to oil is about 6:1, the temperature of the fixed bed, 65 degrees C and the retention time, about 88 min. Also a kind of acidified oil, namely trap grease, with the acid value being 114 mg KOH.g(-1) could be equally converted to a good biodiesel product through this system. Generally, the refined biodiesel product generated through this system could meet China #0 Biodiesel Standard, as well as Germany Biodiesel Standard for most indexes. It indicates that the designed process in this system has a good adaptability for different kinds of oil.

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As a kind of waste collected from restaurants, trap grease is a chemically challenging feedstock for biodiesel production for its high free fatty acid (FFA) content. A central composite design was used to evaluate the effect of methanol quantity, acid concentration and reaction time on the synthesis of biodiesel from the trap grease with 50% free fatty acid, while the reaction temperature was selected at 95 degrees C. Using response surface methodology, a quadratic polynomial equation was obtained for ester content by multiple regression analysis. Verification experiments confirmed the validity of the predicted model. To achieve the highest ester content of crude biodiesel (89.67%), the critical values of the three variables were 35.00 (methanol-to-oil molar ratio), 11.27 wt% (catalyst concentration based on trap grease) and 4.59 h (reaction time). The crude biodiesel could be purified by a second distillation to meet the requirement of biodiesel specification of Korea.

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The production of biodiesel is greatly increasing due to its enviromental benefits. However, production costs are still rather high, compared to petroleum-based diesel fuel. The introduction of a solid heterogeneous catalyst in biodiesel production could reduce its price, becoming competitive with diesel also from a financial point of view. Therefore, great research efforts have been underway recently to find the right catalysts. This paper will be concerned with reviewing acid and basic heterogeneous catalyst performances for biodiesel production, examining both scientific and patent literature.

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This paper describes an attractive method to make biodiesel from soybean soapstock (SS). A novel recovery technology of acid oil (AO) from SS has been developed with only sulfuric acid solution under the ambient temperature (25 +/- 2 degrees C). After drying, AO contained 50.0% FFA, 15.5% TAG 6.9% DAG 3.1% MAG 0.8% water and other inert materials. The recovery yield of AO was about 97% (w/w) based on the total fatty acids of the SS. The acid oil could be directly converted into biodiesel at 95 degrees C in a pressurized reactor within 5 hours. Optimal esterification conditions were determined to be a weight ratio of 1 : 1.5 : 0.1 of AO/methanol/sulfuric acid. Higher reaction temperature helps to shorten the reaction time and requires less catalyst and methanol. Ester content of the biodiesel derived from AO through one-step acid catalyzed reaction is around 92%. After distillation, the purity of the biodiesel produced from AO is 97.6% which meets the Biodiesel Specification of Korea. The yield of purified biodiesel was 94% (w/w) based on the total fatty acids of the soapstock.

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In the study, a novel microemulsion system, consisting of water, iso-propanol and n-butanol, was developed to synthesize the nanostructured La0.95Ba0.05MnAl11O19 catalyst with high surface area and catalytic activity for methane combustion.

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Nanoparticles of BaLiF3:Er3+ were prepared from the quaternary microemulsions of Cetyltrim-Enthyl Ammonium Bromide (CTAB), n-butanol, n-octane, and water, using the hydrothermal-microemulsion technique. The complex fluorides were characterized by means of X-ray power diffraction, Environmental Scanning Electron Microscopy (ESEM), and fluorescence spectra.

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Novel three-dimensional (3D) flowerlike MnWO4 micro/nanocomposite structure has been successfully synthesized for the first time. The synthesized products were systematically studied by X-ray powder diffraction (XRD), field-emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) and photoluminescence (PL) spectra. It is found that both reaction time and temperature have significant effects on the morphology of the products.

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Uniform rare earth phosphate (REPO4, RE = La-Tb) nanocrystals were successfully synthesized in a properly designed TBP/[Omim]Cl/H2O (tributylphosphate/1-octyl-3-methyl-imidazolium chloride/water) microemulsion system. The phosphoryl groups anchored the TBP molecules oil the surfaces of the nanocrystals, and this made the nanocrystals easily dispersed in some imidazolium-based ILs. LaPO4:Eu3+ and CePO4:Tb3+ nanocrystals capped with TBP showed bright red and green emission under UV excitation, with enhanced emission intensity and lifetimes compared with the uncapped ones.

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Europium doped hydroxyapatite (Eu:HAp) nanosized particles with multiform morphologies have been successfully prepared via a simple microemulsion-mediated process assisted with microwave heating. The physicochemical properties of the samples were well characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectra (XPS), Fourier transform infrared spectroscopy (FT-IR), photoluminescence (PL) spectra, and the kinetic decays, respectively. The results reveal that the obtained Eu:HAp particles are well assigned to the hexagonal lattice structure of the hydroxyapatite phase. Additionally, it is found that samples exhibit uniform morphologies which can be controlled by altering the pH values. Furthermore, the samples show the characteristic D-5(0)-F-7(1-4) emission lines of Eu3+ excited by UV radiation.

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Barium lithium fluoride nanocrystals were synthesized in cetyltrimethylammonium bromide (CTAB)/2-octanol/water microemulsion systems. The impurity peaks in XRD patterns were not determined. The result of SEM confirmed that the average sizes and shape of the BaLiF3 nanocrystals. The formation of BaLiF3 and particles size were strongly affected by water content. With increasing water content and reaction times, the size of the particle. increases. Meanwhile, the solvent was also found to play a key role in the synthesis of the BaLiF3 nanocrystals.

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Indium hydroxide, In(OH)(3), nano-microstructures with two kinds of morphology, nanorod bundles (around 500 nm in length and 200 nm in diameter) and caddice spherelike agglomerates (around 750 - 1000 nm in diameter), were successfully prepared by the cetyltrimethylammonium bromide (CTAB)/water/cyclohexane/n-pentanol microemulsion-mediated hydrothermal process. Calcination of the In(OH)(3) crystals with different morphologies (nanorod bundles and spheres) at 600 degrees C in air yielded In2O3 crystals with the same morphology. X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and photoluminescence (PL) spectra as well as kinetic decays were used to characterize the samples. The pH values of microemulsion play an important role in the morphological control of the as-formed In(OH)(3) nano-microstructures from the hydrothermal process. The formation mechanisms for the In( OH) 3 nano- microstructures have been proposed on an aggregation mechanism. In2O3 nanorod bundles and spheres show a similar blue emission peaking around 416 and 439 nm under the 383-nm UV excitation, which is mainly attributed to the oxygen vacancies in the In2O3 nano-microstructures.