Kinetic modeling of the biodiesel production from sunflower oil over corn cob ash

The investigation of reaction kinetics is crucial for practical implications in process equipment design and scaling up. In this study, a kinetic analysis of the methanolysis of a blend of radish and castor oil catalyzed by calcium oxide was carried out. The objectives were to propose a comprehensive model for describing the kinetics of this methanolysis reaction and determine its activation energy. The methanolysis was conducted in a batch reactor under atmospheric pressure with the following reaction conditions: a radish-to-castor oil blend mass ratio of 1:1, a methanol-to-oil molar ratio of 12:1, a catalyst amount of 5% of the oil blend weight, and reaction temperatures of 30 C, 45 C, and 60 C. The model involving the changing reaction mechanism and the triacylglycerol (TAG) mass transfer limitation was first simplified to a pseudo-first order model regarding TAGs and fatty acid methyl esters, which was then used to calculate the apparent reaction rate constant. A good agreement between the calculated and experimental values of the TAG conversion degree was proved by a low mean relative percentage deviation of ±6.1% (based on 66 data), thus validating the applied simple kinetic model. A positive effect of the reaction temperature on the apparent reaction rate constant was observed. Using the Arrhenius equation, the activation energy of methanolysis was determined to be 46.12 kJ/mol. The obtained value of activation energy is much lower than values of activation energy determined for the calcium oxide-catalyzed methanolysis of single oil feedstocks, such as soybean, canola, Jatropha, and waste frying oils. The lower activation energy suggests the potential for enhanced efficiency and feasibility of utilizing this blend as a feedstock for biodiesel production compared to the individual oily feedstocks previously studied

Kinetic Modeling of Sunflower Oil Methanolysis Catalyzed by Calcium-Based Catalysts

The kinetic model originally developed for quicklime-catalyzed methanolysis of sunflower oil was tested for another three calcium-based catalysts, namely, neat CaO, Ca(OH)2, and CaO·ZnO. This model includes the changing reaction mechanism and the triacylglycerol (TAG) mass transfer. The applicability and generalization capability of this model for heterogeneous methanolysis reaction catalyzed by calcium-based catalysts was evaluated. As indicated by the high coefficient of determination and the relatively small mean relative percentage deviation, the model was a reliable predictor of the time variation of TAG conversion degree in the sunflower oil methanolysis over all four calcium-based catalysts within the ranges of the reaction conditions applied. This model is recommended in general for describing the kinetics of sunflower oil methanolysis over calcium-based catalysts.The kinetic model originally developed for quicklime-catalyzed methanolysis of sunflower oil was tested for another three calcium-based catalysts, namely, neat CaO, Ca(OH)2, and CaO·ZnO. This model includes the changing reaction mechanism and the triacylglycerol (TAG) mass transfer. The applicability and generalization capability of this model for heterogeneous methanolysis reaction catalyzed by calcium-based catalysts was evaluated. As indicated by the high coefficient of determination and the relatively small mean relative percentage deviation, the model was a reliable predictor of the time variation of TAG conversion degree in the sunflower oil methanolysis over all four calcium-based catalysts within the ranges of the reaction conditions applied. This model is recommended in general for describing the kinetics of sunflower oil methanolysis over calcium-based catalysts

Continuous sunflower oil methanolysis over quicklime in a packed-bed tubular reactor

The continuous sunflower oil methanolysis catalyzed by quicklime in a packed-bed tubular reactor of 60 cm height was studied at 60 °C using methanol-to-oil molar ratios from 6:1 to 18:1 and weight hourly space velocities from 0.188 to 0.376 (kg/kgcat h). The main goal was to establish the effect of the process variables on the fatty acid methyl esters (FAME) synthesis. A full factorial design was used to evaluate the significance of the three process factors (methanol-to-oil molar ratio, flow rate of the reactants and bed height) statistically. Moreover, the recently reported kinetic model of methanolysis was used to describe variations of FAME and triacylglycerols (TAG) concentrations along the reactor length. The kinetic model predicted the axial concentration profiles of TAG and FAME in the reactor with acceptable accuracy. A high FAME content (98.5%) could be achieved at the two thirds of the bed of quicklime bits without loss of catalytic activity within 30 h of continuous operation

Heterogena bazno katalizovana metanoliza biljnih ulja - presek stanja

Today, homogeneous base-catalyzed methanolysis is the most frequently used method for industrial biodiesel production. High requirements for the quality of the feedstocks and the problems related to the huge amount of wastewaters have led to the development of novel biodiesel production technologies. Among them, the most important is heterogeneous base-catalyzed methanolysis, which has been intensively investigated over the last decade in order to develop new catalytic systems, optimize the reaction conditions and to recycle catalysts. These studies are a basis for continuous development of biodiesel production on an industrial scale in the near future. The presented work summarize up-to-date studies on biodiesel production by heterogeneous base-catalyzed methanolysis. The main goals were to point out the application of different base compounds as catalysts, the methods of catalyst preparation, impregnation on carriers and recycling as well as the possibilities to improve existing base-catalyzed biodiesel production processes and to develop novel ones.Homogena bazno katalizovana metanoliza je najčešće primenjivan postupak dobijanja biodizela u industrijskim uslovima. Visoki zahtevi u pogledu kvaliteta uljnih sirovina i ekološki problemi otpadnih voda doprineli su razvoju novih postupaka sinteze biodizela. Među njima značajno mesto zauzima heterogena bazno katalizovana metanoliza ulja, koja je u poslednjoj deceniji intenzivno proučavana sa aspekta razvoja novih katalitičkih sistema, optimizacije reakcionih uslova metanolize i mogućnosti reciklovanja katalizatora. Ispitivanja ovakvih sistema čine osnovu za razvoj kontinualnih postupaka heterogene bazno katalizovane metanolize, na kojima će se u bliskoj budućnosti bazirati industrijska proizvodnja biodizela. U ovom radu analizirana su dosadašnja ispitivanja postupaka dobijanja biodizela heterogenom bazno katalizovanom metanolizom. Cilj rada je da se ukaže na primenu različitih baznih jedinjenja kao katalizatora, načine njihove pripreme, nanošenja na nosače i recikliranja, kao i na mogućnosti unapređenja postojećih i razvoja novih procesa dobijanja biodizela baznom katalizom

Continuous biodiesel production under subcritical condition of methanol - Design of pilot plant and packed bed reactor with MnCO3/Na-silicate catalyst

The continuous biodiesel production from soybean oil was carried out under the subcritical condition of methanol with MnCO3/Na-silicate as a heterogeneous catalyst. The transesterification rate was first investigated in a set of experiments performed in a batch autoclave at 448 K using methanol-to-oil molar ratio of 18:1 and various catalyst loadings (5, 10 and 20 wt% based on the oil mass). The results from these experiments, as well as the experimental data and the appropriate kinetic model recently reported in the literature were used for designing a packed bed tubular reactor (PBTR), a main unit of the pilot plant with the capacity of 100 L of biodiesel per day. The pilot plant was constructed and tested under various operating conditions. The first 11 h of the pilot-plant operation was realized in the tubular reactor packed with inert glass beads (i.e. without the catalyst) in order to analyze the effect of the non-catalyzed subcritical biodiesel (fatty acid methyl esters, FAME) production. Then, glass beads were replaced with a mix of MnCO3/Na-silicate catalyst particles and glass beads, and the catalytic biodiesel production was continuously run under the subcritical methanol condition for 85 h. Two mass balance tests during the continuous pilot plant operation were performed

Optimization and kinetic modeling of waste lard methanolysis in a continuous reciprocating plate reactor

Continuous biodiesel production from a waste pig-roasting lard, methanol and KOH was carried out in a reciprocating plate reactor (RPR) using a factorial design containing three process factors, namely methanol/lard molar ratio, catalyst loading, and normalized height of the reactor. The main goals were to optimize the influential process factors with respect to biodiesel purity using the response surface methodology and to model the kinetics of the transesterification reaction in order to describe the change of triacylglycerols (TAG) and fatty acid methyl esters (FAME) concentrations along the RPR height. The first-order rate law was proved for both the reaction and the mass transfer. The model of the changing reaction mechanism and mass transfer of TAG was also applicable. Both kinetic models agreed with the experimental concentrations of TAG and FAME determined along the RPR height

Biodiesel production by methanolysis of waste lard from piglet roasting over quicklime

Waste lard from piglet roasting and quicklime (basically CaO) as a priceless fatty feedstock and a cheap solid catalyst, respectively were tested for the biodiesel production by methanolysis in a batch stirred reactor at moderate reaction temperatures (40-60 degrees C) for the kinetic study. For comparison, unheated and heated pork lards, as well as pure CaO, were also included in this study. The mass transfer limitation was observed in the initial period of all methanolysis reactions. The kinetic model combining the changing-and first-order reaction rate laws with respect to triacylglycerols and fatty acid methyl esters (FAMEs), respectively was verified for all three lardy feedstocks and both catalysts. The catalytic activity of quicklime was the same as that of pure CaO. The activation energy was demonstrated to be independent of the feedstock and the catalyst (59.1 +/- 0.6 kJ/mol) but the waste lard reacted faster than the unheated and heated pork lards. At the methanol-to-lard molar ratio of 6:1, the catalyst amount of 5% (based on the lard weight) and the reaction temperature of 60 degrees C, a high FAME concentration in the final ester products (97.5%) within 60 min were achieved with the waste lard and quicklime in two consecutive batches. The same kinetic model was applicable in a continuous packed-bed tubular reactor filled with quicklime bits (2.0-3.15 mm) at the methanol-to-waste lard molar ratio of 6:1, the reaction temperature of 60 degrees C and the residence time of 1 h. Under these conditions, the biodiesel yield was 97.6%, while the FAME concentration in the biodiesel product was 96.5%

Valorization of walnut shell ash as a catalyst for biodiesel production

The catalytic activity of the walnut shell ash was investigated in the biodiesel production by the sunflower oil methanolysis. The catalyst was characterized by the TG-DTA, XRD, Hg porosimetry, Ny physisorption, SEM, and Hammett method. In addition, the effects of the catalyst loading and the methanolto-oil molar ratio on the methyl esters synthesis were tested at the reaction temperature of 60 degrees C. The walnut shell ash provided a very fast reaction and a high FAME content (over 98%). As the reaction occurred in the absence of triacylglycerols mass transfer limitation, the pseudo-first-order model was employed for describing the kinetics of the reaction. The catalyst was successfully reused four times after the regeneration of the catalytic activity by recalcination at 800 degrees C