Biodiesel Synthesis Monitoring using Near Infrared Spectroscopy (original) (raw)
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Monitoring Biodiesel Fuel Quality by near Infrared Spectroscopy
Journal of Near Infrared Spectroscopy, 2007
Biodiesel is produced mainly by a transesterification reaction which involves the reaction of vegetable oils, animal fats or waste oils with an alcohol (such as methanol) in the presence of a catalyst (such as sodium hydroxide or methoxide). Since the presence of contaminants can cause severe engine problems, the assessment of the biodiesel quality is very important. This work reports the use of near infrared (NIR) spectroscopy to determine the content of water and methanol in industrial and laboratory-scale biodiesel samples. A qualitative analysis of the spectra by principal components analysis was carried out and partial least squares regression was used to develop calibration models between spectral and analytical data. The results indicate that the use of NIR spectroscopy, in combination with multivariate calibration, is a promising technique to assess the biodiesel quality in both laboratory-scale and industrial-scale samples.
Journal of Near Infrared Spectroscopy, 2008
Biodiesel is a mixture of fatty acid methyl esters, derived from vegetable oils or animal fats, which is usually produced by a transesterification reaction, where the oils or fats react with an alcohol in the presence of a catalyst. The quality of the oils used for biodiesel production strongly influences the final properties of biodiesel, namely its compliance to the European Standard. This work reports the use of near infrared (NIR) spectroscopy in the quality control of several oil properties, such as the iodine value, the water content and the acid number but, more importantly, the weight–weight percentages (wt%) of soybean, palm and rapeseed oil in mixtures. Principal component analysis was used to perform a qualitative analysis of the spectra, whereas partial least squares regression allowed the development of calibration models between analytical reference data and NIR spectra. The calibration ranges were 60–126 g I2 100 g−1 for the iodine value, 478–2500 mg kg−1 for the wate...
Fuel, 2019
In this work, the use of a handheld near-infrared spectrometer (MicroNIR) for on-line monitoring of biodiesel production in a continuous process is described. The process consists of a laboratory scale reactive distillation column where transesterification reactions between cottonseed oil and ethanol take place. This column can operate with different ethanol to oil molar ratios. In the present study, a severe condition using an excess of ethanol at the point monitored with NIRS was applied. This condition caused problems in modelling the content of the alkyl ester, particularly because of the broad and intense band related to the ethanol in the spectral region covered by MicroNIR. Therefore, for process monitoring and control, both an estimate of the alkyl ester as well as of ethanol contents were carried out. To deal with this, PLS calibration models were developed to estimate concentrations of ethanol and alkyl ester at the bottom of the column. In addition, in order to estimate the yield of the alkyl ester, a PLS model to assess glycerol content was also developed. In spite of the problematic conditions under which the column operated, mainly related to the excess of ethanol, the models presented satisfactory results for ethanol (RMSEP = 1.66 wt%), alkyl ester (RMSEP = 2.15 wt%) and glycerol (RMSEP = 1.08 wt%) quantifications and have demonstrated the feasibility of the handheld instrument to monitor biodiesel production in a continuous process.
2017
. The use of ethanol and biodiesel, which are alternative fuels or biofuels, has increased in the last few years. Modern official standards list 25 parameters that must be determined to certify biodiesel quality. In order to determine biofuel quality, several methods were already widely used in which most of them were based on solvent extraction followed by other laboratory procedures. Yet, these methods are expensive, laborious and complicated processing for samples. Near infrared reflectance spectroscopy (NIRS) can be considered as a fast, pollution-free and non-destructive method in determining biofuel quality parameters. The objective of this study is to apply near infrared technology in classifying biodiesel based on KOH (0.3, 0.5 and 0.7) and to predict related biodiesel quality properties (water content, linolenic fatty acid, oleic acid, and stearic acid) based on its infrared reflectance. Biodiesel infrared spectrum was acquired in wavelength range from 1000 to 2500 nm for d...
Journal of Chemical Education, 2012
Biodiesel has gained attention in recent years as a renewable fuel source due to its reduced greenhouse gas and particulate emissions, and it can be produced within the United States. A laboratory experiment designed for students in an upper-division undergraduate laboratory is described to study biodiesel production and biodiesel mixing with conventional petroleum-based diesel fuel using Fourier transform infrared (FTIR) spectroscopy. The production of biodiesel from oil via a transesterification reaction is monitored by the intensity of the C−O ester peak (1098 cm-1), whereas the mixing of biodiesel and petroleum-based diesel is monitored by the CO ester stretch (1746 cm −1). The impact of water on the precision of the biodiesel mixture is determined using a Karl Fischer titration to monitor water content. Students also gain experience with method validation using multiple sampling platforms (liquid cell, ATR-cell, and IR card). At the conclusion of the experiment, students are able to use FTIR to quantitatively monitor reactions and determine mixtures, determine the impact of water content on quantitation, and evaluate the strengths and weaknesses of different sampling platforms for various applications.
Bioresource Technology, 2011
Many analytical procedures have been developed to determine the composition of reaction mixtures during transesterification of vegetable oils with alcohols. However, despite their accuracy, these methods are time consuming and cannot be easily used for on-line monitoring. In this work, a fast analytical method was developed to on-line monitor the transesterification reaction of high oleic sunflower oil with ethanol using Near InfraRed spectroscopy and a multivariate approach. The reactions were monitored through sequential scans of the reaction medium with a probe in a one-liter batch reactor without collecting and preparing samples. To calibrate the NIR analytical method, gas chromatography-flame ionization detection was used as a reference method. The method was validated by studying the kinetics of the EtONa-catalyzed transesterification reaction. Activation energy (51.0 kJ/mol) was also determined by considering a pseudo second order kinetics model.