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Biodiesel is a clean burning fuel derived from a renewable feedstock such as vegetable oil or animal fat. It is biodegradable, non-inflammable, non-toxic, and produces lesser carbon monoxide, sulfur dioxide, and unburned hydrocarbons than petroleum-based fuel. The purpose of the present work is to present an efficient process using reactive distillation columns applied to biodiesel production. Reactive distillation is the simultaneous implementation of reaction and separation within a single unit of column. Nowadays, it is appropriately called "Intensified Process". This combined operation is especially suited for the chemical reaction limited by equilibrium constraints, since one or more of the products of the reaction are continuously separated from the reactants. This work presents the biodiesel production from soybean oil and bioethanol by reactive distillation. Different variables affect the conventional biodiesel production process such as: catalyst concentration, reaction temperature, level of agitation, ethanol/soybean oil molar ratio, reaction time, and raw material type. In this study, the experimental design was used to optimize the following process variables: the catalyst concentration (from 0.5 wt.% to 1.5 wt.%), the ethanol/soybean oil molar ratio (from 3:1 to 9:1). The reactive column reflux rate was 83 ml/min, and the reaction time was 6 min.

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Some important properties of biodiesel such as viscosity, melting point, thermal stability, and cetane index can be directly related to the chemical composition of the biomass source used. However, the viscosity of castor oil ethyl ester (COEE) is about four times greater than the biodiesel viscosity specification, and this fact restricts the uses of this biofuel. The main goal of this work is to investigate the physical–chemical properties of COEE in ethanol blends and present an option to decrease the castor oil biodiesel viscosity specification. COEE viscosity is 14.413 mm2/s. The results show an evident decrease in biodiesel viscosity with the addition of ethanol. Samples with 30, 40, and 50 vol % of ethanol present the following viscosities 5.316, 4.044, and 3.136 mm2/s, respectively. These results are in agreement with Brazilian National Agency of Petroleum, Natural gas and Biodiesel (ANP), and European (EN 14214) specifications. Three correlations that describe the decrease in viscosity and density with ethanol concentration, and the variation of viscosity with the density in COEE ethanol blends were obtained. The behavior of COEE ethanol blends with diesel also were analyzed. The increase in solubility of ethanol in commercial diesel was verified because COEE acts as a cosolvent in an ethanol–diesel mixture.

In this work, the reactive distillation process for biodiesel production using castor oil and soybean oil as feedstocks is presented.Process simulations using the commercial simulator Aspen plus ® in conjunction with factorial design techniques were used for finding the process operating conditions that will produce the largest amount of biodiesel.For the simulations, firstly, the characterization of vegetable oils and biodiesels by means of representative compounds was performed into the simulator. It was necessary, for a successfull characterization, to carry out experimental measurements of some properties of these compounds. The simulations were performed using the NRTL thermodynamic model. The interaction parameters missing in the simulator data base were estimated by UNIFAC method. The kinetic model employed in castor oil study was published by de Lima da Silva. Because kinetic data for soybean oil transesterification with ethanol are not reported in the open literature, these parameters were determined and used in the simulations.In the study of the castor oil biodiesel production system, initially a 2 4 factorial design was done in order to analyze the effect of the variables: feed flow rate of oil (vo), molar ratio alcohol: oil (rm), reflux ratio (rf) and molar ratio between the distillate / feed based on ethanol (d: f) in the process yield and simultaneously to obtain a model that adequately represents the behavior of the system. Following this, it was used the method of the path of steepest ascent to determine quickly and simply the region that will maximize the production of biodiesel. Finally, based on results obtained in the previous section, it was developed a new factorial design 2 4 to find the best combination of variables, which would provide the largest biodiesel production. Sensitivity studies were performed to support the factorial design results. In the study of the system involving soybean oil, was followed the vii same methodology described for the castor oil, with the difference that the factorial designs were all 2 3 . The results obtained with the twou oils show that it is possible to obtain high yields in the process using a low molar ratio ethanol: oil and a more compact plant.Additionally, it was introduced in the simulations, stage efficiency values and component efficiency values calculated using the Barros & Wolf equation. It was concluded that efficiency has no effect on the performance of the reactive distillation process for biodiesel production.Finally, it was performed a simulation of a reactive packed distillation column for biodiesel production. The operating conditions of the simulation were taken from an experimental study conducted by the research group in biodiesel lab LDPS, which is reported in this dissertation.