Analysis of Methanol Gasoline by ATR-FT-IR Spectroscopy

Qi XIA,Liuwei MENG,Xiaojing CHEN,Lei-ming YUAN,Guangzao HUANG

doi:10.3390/app9245336

Qi XIA, Liuwei MENG + Show 3 more

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https://doi.org/10.3390/app9245336

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Abstract

Methanol gasoline blends are a more economical, and environmentally friendly fuels than gasoline alone, and are widely used in the transportation industry. The content of methanol in methanol gasoline plays an important role in ensuring the quality of gasoline. In some solutions, due to the shortage of energy and illegal profits, the problem of gasoline adulteration and its fineness, has received more and more attention, which would seriously affect the operating condition and service life of internal combustion engines. Therefore, it is very important to identify the correct level of gasoline. However, the traditional detection method is complex and time-consuming. To this end, the feasibility of using attenuated total reflectance Fourier transform infrared (ATR-FTIR) methods coupled with chemometrics methods were investigated to quantitatively and qualitatively analyze methanol gasoline. The qualitative analysis result of partial least squares discriminant analysis (PLS-DA) obtained 100% and 98.66% accuracy in the calibration set and the prediction set, respectively. As for quantitative analysis; two regression algorithms of partial least squares regression (PLSR) and the least square support vector machine (LS-SVM), as well as two variables selection methods of the successive projections algorithm (UVE) competitive adaptive reweighted sampling (CARS) and uninformative variable elimination (UVE) were combined to establish the quantitative model. By comparing the performance of the optimal models; the UVE-PLSR model performed best with a residual predictive deviation (RPD) value of 6.420. The qualitative and quantitative analysis results demonstrate the feasibility of using ATR-FTIR spectra to detect the methanol in methanol gasoline. It is believed that the promising IR spectra will be widely used in gasoline energy quality control in the further.

Highlights

Gasoline is one of the most widely used light petroleum products and a complex hydrocarbon mixture usually containing four to thirteen carbon atoms [1]
An excellent regression model usually has the high value of Rc2, Rp2, residual predictive deviation (RPD), and the smaller value of root mean square error of calibration (RMSEC), RMSEP and ABS [29]
The spectral range of 900–600 cm−1 has a lower ratio of signals to noises (RSN), and this region would be discarded in further analysis of spectral information

Summary

Introduction

Gasoline is one of the most widely used light petroleum products and a complex hydrocarbon mixture usually containing four to thirteen carbon atoms [1]. Sci. 2019, 9, 5336 transportation industry has led to a reduction in non-renewable oil resources and the increasingly serious atmospheric pollution problem [2] To address this issue, it is necessary to find an environmentally, friendly, and economically viable alternative resource. Methanol gasoline as an excellent alternative fuel for engines, which has advantages such as high octane number, and good resistance to violent and clean burning [3] Due to these excellent qualities and appropriate economic suitability, methanol gasoline can play an important role in addressing the issue of energy shortage and environmental pollution. It has been widely used in transportation, including motor vehicles and internal combustion engines [4]. This provides an opportunity for some unscrupulous traders to sell high-methanol gasoline at a low methanol content of gasoline to earn illegal profits

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