Test method for determination of different biodiesels (fatty acid alkyl esters) content in diesel fuel using FTIR-ATR
Graphical abstract
Introduction
Methanol is used in biodiesel production due to its availability and low price, but it is also toxic, volatile, and mostly produced from fossil origin. Its main alternative in biodiesel production via transesterification of vegetable oil is ethanol, which is less toxic and produced in large quantities from biomass [1]. Moreover, there are several studies that focus on the use of other alternative alcohol feedstocks for transesterification such as 1-propanol [[2], [3], [4], [5]], 2-propanol [2,3,6,7], 1-butanol [2,3,6], 2-butanol [2,3,5,7], isobutanol [2], tert-butanol [5,6], 2-methyl-1-butanol [2], 2,2-dimethylpropan-1-ol [2,5], 4-methylpentan-2-ol [2], 2-ethylhexanol [7], 1-pentanol [2], 2-hexanol [3], 1-hexanol [3], 1-octanol [3,4], 2-octanol [3], and 1-decanol [3]. Excluding methanol and ethanol which are wildly studied, most of these studies examine the application of butanol because it can be produced from biomass [8,9]. Furthermore, butanol has a number of advantages over ethanol: it is less corrosive, less soluble in water, less volatile, it has a higher energy density, and it can be directly blended with diesel without compromising its application properties [10] eliminating the problem with residual alcohol [11]. Several fermentation process that produce butanol have gained a lot of attention (ABE - acetone/butanol/ethanol fermentation [12] and non-ABE fermentation [11]). One of the drawbacks is the cost of substrate which also may compete with food production. Glycerol was examined as an alternative substrate for butanol production [13,14] as it is readily available at a low price as a by-product of transesterification, becoming an environmental liability because of its massive production [11,15]. This approach could achieve an integrated and more sustainable production of biobutanol and biodiesel. Thus, by replacing methanol, a more environmentally friendly transesterification process and feedstock diversification could be achieved.
Fast and low-cost analytical methods would ease the research and development of these alternative fatty acid alkyl esters (FAAEs) as well as its industrial application. The use of fatty acid methyl ester (FAME) alone or blended with diesel fuels is regulated by European standard EN 590 which states that diesel fuel can contain up to 7.0 vol% of FAME. The specified standard test method for determination of FAME content in diesel fuel uses infrared spectroscopy, a well-known procedure described in standards ASTM D7371-14 [16] and EN 14078 [17]. FTIR is rapid, easy to use and part of standard laboratory equipment. The object of this study is to develop and test the applicability of two quantitative methods for precise determination of biodiesel content in the range from 0 to 30 vol% for ethyl, propyl, butyl, isobutyl, pentyl, isopenyl, hexyl, heptyl, octyl, decyl, and dodecyl fatty acid esters (FAAE) in diesel. Currently such a method is not available; i.e. the determination of higher alcohol fatty acid esters content in the biodiesel/diesel mixture and the influence of alcohol on the determination were not studied. Since alcohol is added in excess to achieve higher yields of biodiesel during transesterification, the influence of (residual or added on purpose) alcohol (1–200 vol%. of corresponding biodiesel) in FAAE/diesel blends on the results was investigated.
Section snippets
Materials
Diesel fuel that satisfies the requirements of EN 590 standard, without FAME and without any additives was obtained from INA Petroleum Industry refinery. The characteristics of the diesel are: density (832.9 kg m−3), water content (27 mg kg−1), kinematic viscosity (2.646 mm2 s−1), cetane index (51.4), and sulfur content (3.9 ppm). Methyl, ethyl, propyl, butyl, isobutyl, pentyl, isopenyl, heptyl, octyl, decyl, and dodecyl fatty acid esters were synthetized by transesterification of sunflower oil
Calibration curves for quantification of FAAEs in diesel fuel
The FTIR spectra of diesel fuel, glycerol, ethanol, decanol, fatty acid ethyl ester, and fatty acid decyl ester are presented in Fig. 1. All sample spectra have characteristic signals corresponding to CH stretching of alkyl groups in range from 2800 to 3000 cm−1. Signals at 1458 and 1377 cm−1, which correspond to CHx bending, are also present in all sample spectra, but less pronounced in glycerol and ethanol. Meanwhile, the wide signal from 3050 to 3600 cm−1, which belongs to OH, is present
Conclusion
The method that uses FTIR-ATR CO signal area (1690 - 1800 cm−1) can be used to quantitatively determine the amount of methyl, ethyl, propyl, butyl, isobutyl, pentyl, isopentyl, hexyl, heptyl, octyl, decyl, and dodecyl fatty acid ester in biodiesel diesel blends. The standard test method that is used for determination of fatty acid methyl ester in diesel can also be applied for other alkyl fatty acid ester (ethyl, propyl, butyl, isobutyl, pentyl, isopentyl, hexyl, heptyl, octyl, decyl, and
References (25)
- et al.
Second generation bioethanol production: a critical review
Renew. Sustain. Energy Rev.
(2016) - et al.
Properties of rapeseed oil fatty acid alkyl esters derived from different alcohols
Fuel
(2014) - et al.
Biodiesel production through transesterification of triolein with various alcohols in an ultrasonic field
Renew. Energy
(2009) - et al.
Synthesis of bio-diesel and bio-lubricant by transesterification of vegetable oil with lower and higher alcohols over heteropolyacids supported by clay (K-10)
Process Saf. Environ. Protect.
(2007) - et al.
Transesterification of canola, palm, peanut, soybean and sunflower oil with methanol, ethanol, isopropanol, butanol and tert-butanol to biodiesel: modelling of chemical equilibrium, reaction kinetics and mass transfer based on fatty acid composition
Appl. Energy
(2014) - et al.
Cold flow properties of fatty esters
Process Saf. Environ. Protect.
(2007) - et al.
n-Butanol derived from biochemical and chemical routes: a review
Biotechnol. Rep.
(2015) - et al.
Bioproduction of butanol from biomass: from genes to bioreactors
Curr. Opin. Biotechnol.
(2007) - et al.
Effects of butanol–diesel fuel blends on the performance and emissions of a high-speed DI diesel engine
Energy Convers. Manag.
(2010) - et al.
ABE fermentation products recovery methods—a review
Renew. Sustain. Energy Rev.
(2015)
Anaerobic fermentation of glycerol: a path to economic viability for the biofuels industry
Curr. Opin. Biotechnol.
Glycerol: a promising and abundant carbon source for industrial microbiology
Biotechnol. Adv.
Cited by (22)
Investigation and impact assessment of soybean biodiesel, methyl oleate, and diesel blends on CRDI performance and emissions
2024, Materials Science for Energy TechnologiesEffect of synthesized lemongrass biodiesel on the performance and emission characteristics of a CI engine
2023, Sustainable Energy Technologies and AssessmentsResearch on a fluorine-containing asphaltene dispersant and its application in improving the fluidity of heavy oil
2023, Journal of Molecular LiquidsData fusion of middle-resolution NMR spectroscopy and low-field relaxometry using the Common Dimensions Analysis (ComDim) to monitor diesel fuel adulteration
2022, TalantaCitation Excerpt :Therefore, robust and low-cost analytical tools are needed to tackle fuel adulteration. The chromatographic and spectroscopic techniques, allied to chemometrics methods, have demonstrated outstanding potential for use in investigations of fuel adulteration [2,3,12–15]. Low-field proton nuclear magnetic resonance (LF-1H NMR), such as medium-resolution (MR-1H NMR) or time-domain NMR (TD-1H NMR), have been extensively applied in the routine analysis as a substitute for conventional analytical techniques.
Influence of nature of catalyst on biodiesel synthesis via irradiation-aided transesterification of waste cooking oil-honne seed oil blend: Modeling and optimization by Taguchi design method
2021, Energy Conversion and Management: XCitation Excerpt :Very strong vibrations of asymmetric and symmetric stretching of –C–H (CH2) are observed in the region of 2926 – 2854 cm−1. The carbonyl peak notable for –C = O (ester) is characterized by a very strong intensity at 1745 – 1743 cm−1 [63,64]. The fingerprint region representing ester functional groups is clear and distinct in all spectra in the region 1465 – 1018 cm−1 [35].