In a biodiesel production industry a quick monitorization of the reaction extent achieved in the process it is important. The usual way to determine the reaction yield is to analyze the FAME content in the biodiesel reaction product. Analytic methods used, mainly gas chromatography, require previous sample treatment or tedious calibrations. Recently, less complicated analytic methods (nuclear magnetic resonance, infrared spectrophotometry) have been developed but they require costly equipment and analysis. The aim of this paper is to develop a cheap and fast method in order to quantify the FAME content in the reaction mixture from simple dynamic viscosity measurements and then the transesterification reaction yield. Therefore, experimentally obtained correlations from biodiesel proceeding of several oil feedstocks are presented in order to estimate the biodiesel FAME content from its dynamic viscosity, a fast determination parameter.

Non-polar oil and polar short-chain alcohols, used as reactants in the transesterification reaction, are immiscible. Transesterification reactions can only occur on the phase boundary and they are therefore diffusion-limited. Several methods are employed to overcome the limitation of mass transfer by increasing miscibility and thereby accelerating the reaction. Co-solvents are additional solvents that should be soluble in the oil and alcohol phase; this could lead to an increase in the reaction rate and a reduction in the temperature and the reaction time. This work aims to provide a comprehensive literature review on the influence of co-solvents on the processes of catalysed methanolysis for the biodiesel production. Most authors have not systematically determined and justified the effects of cosolvents. So far it seems impossible to establish which cosolvents are the most suitable for which methanolysis systems. The purpose of this work is to highlight and justify the differences or similarities in co-solvent impacts among the various publications by examining the chemical structure of the respective co-solvents, including the functional groups and the resulting physicochemical properties such as the dielectric constant or the log P value. Besides biodiesel, co-solvents like THF and acetone seems to be the best choices for alkaline methanolysis systems due to successful broadly applications with different oils, catalysts and reaction conditions. Moreover, THF and n-hexane are essentially advisable for in-situ methanolysis.

Due to the success of the use of energy crop oils in the production of biodiesel, the heavy cultivation of these plants in many countries is being promoted. However, it may lead to the problem with its associated waste shells, which contain low nutrient; consequently, they are not suitable for use as an agricultural fertilizer, and they are abundant in hemicellulose, cellulose, and lignin resulting in difficult to digest or degrade. Thus, a possible solution for this waste is to convert it into carbon-based adsorbents. Specifically, activated carbon is a product with a high added value, widely used material due to its adsorbent properties. These adsorbents could be used for reducing the free fatty acids content presents in oils intended for the biodiesel production. The presence of free fatty acids in the oils is undesirable for biodiesel production due to a performance reduction in the transesterification reaction. The aim of this work is to use biomass waste such as Jatropha curcas and Pongamia pinnata shells for the preparation of carbon-based materials (activated carbons, Ca(OH)2 supported on activated carbons and charcoals) and to study the possibility of using them as adsorbents for reducing the free fatty acids content of Jatropha curcas and Pongamia pinnata oils.

In this work, the anaerobic digestion of three microalgae ( Chlorella sp., Nannochloropsis sp., and Scenedesmus sp.) and their residues, resulting from the oil extraction process and the in situ transesterification reaction for biodiesel production, using two inoculums (sewage sludge and poultry manure) for biogas production was investigated. It was found that the biogas production from digestion of oil-extracted microalgae residue with sewage sludge reached values ​​similar to those obtained with raw microalgae (around 500 NL kg −1 VS). Both the volume of biogas generated from the microalgae residue from the extraction process of its oil and the quality of the biogas produced reflect the value of this residue to be valorized by anaerobic digestion. This approach based on a biorefinery concept and focusing on the anaerobic digestion process could be a key technology for energy production from biomass.

The increasing importance of sustainability in energy production has led to a global commitment to the use of fuels derived from renewable biological sources, such as biodiesel produced from plant crops or biomass residues, that do not compete with human food for their production. For a biofuel to be considered biodiesel, it must satisfy the specifications described in the UNE 14214, with the UNE-EN 14103 referring to the determination of fatty acid methyl ester content. This standard applies gas chromatography as an analytical technique. Gas chromatography is a widely used technique in the analysis of methyl ester although it has a number of drawbacks such as: long analysis times, a high consumption of high-quality gases and internal standards, does not allow the analysis of different compounds with the same column, etc. From an industrial production point of view, is necessary to know the fatty acid methyl ester content in biodiesel samples quickly. This paper studies the development of an analytical method using Fourier transform infrared spectroscopy (FTIR) as alternative to gas chromatography (GC), since it is a simple, rapid, and precise analytical technique to quantify fatty acid methyl ester content in biofuel samples.

Co-processing experiments of straight run gas oil (SRGO) with used cooking oil (UCO), and category three animal fat were performed in a hydrotreatment pilot plant. Liquids and gaseous products obtained were analysed and quantified. The aim of the work was the study of the effect of the triglycerides feedstocks co-processing with the diesel fuel on the desulphurized gasoil properties, as well as their impact on the hydrodesulfurization (HDS) and hydrodenitrogenation (HDN) catalyst activities. These results were compared with the co-processing test of refined palm oil. Experiments were performed in a pilot plant that reproduced the hydrotreatment of diesel oil with a conventional NiMo/Al2O3 catalyst, under the following conditions: 350 degrees C 5.5 MPa, LHSV 2 h(-1) and a H-2 to feed oil ratio of 340 NL/L. The ratio SRGO/triglycerides feedstock was always 80/20 wt.%. At these operating conditions, linear paraffins (nC(15)-nC(18)) were the main reaction product (79-85 wt.%), followed by light gases (CO, CO2 and C3H8) and water as by-products. The increment in paraffin content of the liquid product produced a significant variation of some of gasoil properties (density at 15 degrees C and cetane index). A decrease in the catalytic activity (HDS/HDN) was also observed in the co-processing stages, particularly when animal fat was co-processed.

The transesterification reaction is the most utilized process to obtain biodiesel. Fried oil transesterification reactions with methanol have been studied using several zeolites Y and interchanged with CsCl and KOH. The reaction has been carried out both in a slurry reactor and a fixed bed catalytic reactor. The catalytic effects of zeolites have been tested within a temperature range of 60-476°C, 2.5-5% catalyst/waste oil weight ratio, and 6:1 - 100:1 methanol/oil molar ratio. Cosolvents (THF, n-hexane) in the reaction feedstock effect have also been studied as well as catalyst regeneration effects. Viscosity of both the oil and the transesterification reaction products was determined as an initial guide to investigate the degree of conversion to biodiesel as well as FAME content by GC. When interchanged zeolites are used conversions are improved, getting the best yields (98% FAME) for the Y756 zeolite interchanged with KOH. Viscosities of the reaction product obtained reached values next to diesel standard ones.

This work study the catalytic co-hydroprocessing of used frying oil (UFO) with atmospheric gas oil (AGO), paying particular attention to the effect of UFO on the hydrodesulfurization (HDS) and hydrodenitrogenation (HDN) efficiency, the products selectivities and its influence on fuel properties. Hydrotreating experiments were performed in a pilot plant for diesel hydrodesulphurization using a commercial catalyst of NiMo/Al2O3, temperature 320-350 degrees C, pressure 5.5 MPa, WHSV 2 h-1, UFO content 20-50 wt% and H-2/feed ratio 500-1200 NL/L. At the operating conditions used, a total conversion of the triglycerides of UFO was obtained with a 96-99% sulfur elimination. This produced a slightly increase of the HDS/HDN rates during the co-processing, without irreversible effects over its activity and important variation in some properties such as cetane index, density 15 degrees C or kinematic viscosity 40 degrees C. The main products obtained were paraffins with 15 and 17 atoms of carbons and light gases such as CO2 and CH4, which imply that the catalyst used stimulates decarboxylation reactions in detriment of hydrodeoxygenation reactions.

This work proposes a green, simple and rapid chromatographic methodology for separation and determination of a group of 13 fatty acids methyl esters (FAMEs) by using a capillary gas chromatography with a flame ionization detector. The method was successfully applied for the determination of FAMEs in biodiesel samples from commercial and waste cooking oils, synthesized by homogeneous catalysis. Detection and quantification limits were in the μg L−1 level. Direct injection of sample solution was compared with solid-phase extraction and solid-phase microextraction procedures, giving similar results. The lower analysis time represent considerable improvement compared with other papers. The described methodology is especially suitable for process control applications. The samples analysed showed total contents of FAMEs higher than 96.5%, which verifies the European regulations.

Abstract The Faja Petrolifera del Orinoco (FPO), located in the southern part of the Eastern Basin of Venezuela, has the largest reserves of heavy and extra heavy oil in the world. These oils are highly viscous and their API gravities values are between 7 and 15, these properties together with the existence of multiphase flow make the production and transportation of these oil is highly complex. Therefore, it is necessary to use heavy oil transportation methods focused on reducing the viscosity of oil, this is achieved be removing or modifying the oil compounds that have been pointed out as the main cause of the high viscosity of these oils, such as: partial or total upgrading or slurry transportation. This study presents a flow modeling of a solid-liquid dispersion through horizontal pipes, which represents a slurry transportation, using a software of computational fluid dynamics (CFD) called FLUENT 6.3. For the simulation methodology was selected Euler-mixture in a three dimensional pipe model, with different concentrations of solids. The simulations were validated with experimental data development by PDVSA Intevep that contains pressure drops, temperature, solid characterizations and reological behavior of the slurry. The performance evaluation by the CFD model showed an acceptable fit when it is compared against experimental data, this results allow to understand the hydraulic behavior of heavy oil slurry transport through pipeline.

The rheological behavior of 34 commercial food dispersions was investigated and modeled with the Herschel-Bulkley model. Artificial neuronal networks (ANNs) were trained to predict the rheological parameters yield stress tau(0), consistency coefficient K and flow behavior index n in dependency of the composition of fats, carbohydrates, proteins and water. ANNs with 3 hidden layers and 2 neurons per layer showed good to very good results for all Herschel-Bulkley parameters. (c) 2012 Elsevier Ltd. All rights reserved.

Biodiesel as an alternative fuel has become more important in recent times due to the increasing awareness of fossil fuel resources and the environmental benefits. The main disadvantages are its cost and availability of fats and oils resources. By collecting used frying oils and converting them to biodiesel fuel, the cost of biodiesel is significantly lowered and the negative impact of disposing used oil to environment reduced.The aim of this study was to analyse the performance of several alkali metal exchanged zeolites as heterogeneous catalysts for biodiesel production from sunflower oil and waste oil. Several catalysts studied showed a high activity for transesterification reaction with batch or continuous flow reactor operation conditions performed: temperature (100- 155°C), methanol/oil molar ratio (12:1- 72:1 mol/mol) and catalyst concentration (3-6 wt %). Results indicated that biodiesel production using waste oil as feedstock has good potential because it is an inexpensive and available feedstock.

In order for biodiesel to be commercialized as pure biofuel or blending stock for diesel fuels, it must meet a set of requirements defined in standard specifications for a safe and satisfactory engine operation, one of these specifications is the content of fatty acid methyl esters (FAME). Besides, this parameter indicates the performance of the transesterification reaction for biofuel production from vegetable oils. There are several methods to determinate FAME content in biodiesel samples (chromatography, nuclear magnetic resonance spectroscopy and FTIR spectroscopy); however, they take long times and high cost for FAME content determination. From a practical point of view, in industrial biodiesel production is usually necessary to estimate the FAME value quickly. This paper presents correlations experimentally obtained from different oil feedstocks in order to estimate the biodiesel FAME content from the biodiesel dynamic viscosity, a fast determination parameter.

A natural porous silica, pumice, was studied as heterogeneous catalyst in the transesterification reaction of sunflower oil and frying oil with methanol for biodiesel production. This low cost natural porous material was subjected to ion exchange with a KOH aqueous solution in order to increase its activity. The dependence of the reaction variables such as temperature, reaction time, catalyst loading and methanol/oil molar ratio were studied using sunflower oil and waste oil as feedstock. Moreover, in order to save production costs, the reusability of the catalyst in the transesterification reaction was studied.

The use of a heterogeneous catalyst in the transesterification reaction of sunflower oil and waste oil for the production of methyl esters (biodiesel) has been studied. The basic hydrotalcite catalyst used showed a high activity for transesterification reactions in the operation conditions studied. The experiments were performed in a temperature range between 80 and 160 degrees C, in a batch reactor. The methanol/oil molar ratio in the reaction mixture and catalyst concentration ranges used were from 12:1 to 48:1 (mol/mol) and 3-12 (wt % of the initial vegetable oil mass) respectively. Calcined forms of the catalyst were tested. The catalyst was characterized with SEM, XRD, IR, and DTA-TG methods.