Roberta Ceriani

Bio: Roberta Ceriani is an academic researcher from State University of Campinas. The author has contributed to research in topics: UNIFAC & Vegetable oil. The author has an hindex of 22, co-authored 74 publications receiving 1354 citations. Previous affiliations of Roberta Ceriani include Spanish National Research Council & Universidade Federal de Viçosa.

Group Contribution Model for Predicting Viscosity of Fatty Compounds

Abstract: In the present work, a group contribution model is proposed for estimating the dynamic viscosity of fatty compounds. For the major components involved in the vegetable oil industry (such as fatty acids, esters and alcohols, triacylglycerols, and partial acylglycerols), the optimized parameters are reported. In order to improve the data bank gathered from the literature, viscosity data were measured as a function of temperature for three saturated and three unsaturated fatty esters, one unsaturated fatty acid, and one unsaturated triacylglycerol. These last two are unavailable data in the literature (linolenic acid and trilinolenin). A simple method of calculation is also proposed to predict the dynamic viscosity of vegetable oils as an extended applicability of our equation. The model can be a valuable tool for designing processes and equipment for the oil industry, including edible and non-edible compounds, such as biodiesel.

Evaluation of Predictive Models for the Viscosity of Biodiesel

Abstract: Viscosity is an important biodiesel parameter, subject to specifications and with an impact on the fuel quality. A model that could predict the value of viscosity of a biodiesel based on the knowledge of its composition would be useful in the optimization of biodiesel production processes and the planning of blending of raw materials and refined products. This work aims at evaluating the predictive capability of several models previously proposed in the literature for the description of the viscosities of biodiesels and their blend with other fuels. The models evaluated here are Ceriani’s, Krisnangkura’s, and Yuan’s models, along with a revised version of Yuan’s model proposed here. The results for several biodiesel systems show that revised Yuan’s model proposed provides the best description of the experimental data with an average deviation of 4.65%, as compared to 5.34% for Yuan’s model, 8.07% for Ceriani’s model, and 7.25% for Krisnangkura’s model. The same conclusions were obtained when applying thes...

The Design and Analysis of Experiments

Abstract: THE DESIGN AND ANALYSIS OF EXPERIMENTS. By Oscar Kempthorne. New York, John Wiley and Sons, Inc., 1952. 631 pp. $8.50. This book by a teacher of statistics (as well as a consultant for \"experimenters\") is a comprehensive study of the philosophical background for the statistical design of experiment. It is necessary to have some facility with algebraic notation and manipulation to be able to use the volume intelligently. The problems are presented from the theoretical point of view, without such practical examples as would be helpful for those not acquainted with mathematics. The mathematical justification for the techniques is given. As a somewhat advanced treatment of the design and analysis of experiments, this volume will be interesting and helpful for many who approach statistics theoretically as well as practically. With emphasis on the \"why,\" and with description given broadly, the author relates the subject matter to the general theory of statistics and to the general problem of experimental inference. MARGARET J. ROBERTSON

A comprehensive review on properties of edible and non-edible vegetable oil-based biodiesel: Composition, specifications and prediction models

Abstract: In recent decades, the concern over depletion of the world׳s petroleum reserves and environmental pollution has increased the demand to develop a renewable and environmental friendly fuel. Biodiesel, which mainly consists of Fatty Acid Methyl Esters (FAME) is one of the best substitutes for diesel fuel. Currently, vegetable oils, edible or non-edible, are the main resources of biodiesel. This review aims at providing comprehensive information and analyzes on biodiesel produced from edible and non-edible vegetable oils, their composition and specifications. Accordingly, the Fatty Acid (FA) profiles of 28 edible vegetable oils and 40 non-edible vegetable oils were collected. Their main specifications including sulfur content, density, viscosity, flash point, cloud point, pour point, cold filter plugging point, cetane number, iodine number, heating value, acid value and carbon residual before and after transesterification (vegetable oil and biodiesel, respectively) were analyzed in detail. Many researchers have developed prediction models to quantify biodiesel specifications to optimize its manufacturing and obtain biodiesel with the best specifications. Three factors that are especially influential are the fatty acids profiles, the degree of unsaturation within the FA structures and molecular weight. Accordingly, many models have been constructed on these features. There are also models that quantify the relationship between the biodiesel specifications and its thermodynamic properties or other specifications. Accordingly, the second part of this work was conducted on the existing prediction models. All the models were discussed along with their deviation in prediction.

Densities and Viscosities of Fatty Acid Methyl and Ethyl Esters

Abstract: To develop reliable models for the densities and viscosities of biodiesel fuel, reliable data for the pure fatty acid esters are required. Densities and viscosities were measured for seven ethyl esters and eight methyl esters, at atmospheric pressure and temperatures from (273.15 to 363.15) K. A critical assessment of the measured data against the data previously available in the literature was carried out. It is shown that the data here reported presents deviations of less than 0.15 % for densities and less than 5 % for viscosities. Correlations for the densities and viscosities with temperature are proposed. The densities and viscosities of the pure ethyl and methyl esters here reported were used to evaluate three predictive models. The GCVOL group contribution method is shown to be able to predict densities for these compounds within 1 %. The methods of Ceriani and Meirelles (CM) and of Marreiro and Gani (MG) were applied to the viscosity data. It is shown that only the first of these methods is able t...