In the production process of biodiesel using waste cooking oil, organic solvent and catalyst are used. The amount and kind of organic solvent and catalyst are determined depending on the mixed ratio of waste cooking oil, and finally their proportion affects the yield of biodiesel. In this research, we aim to develop a system measuring mixed ratio of raw materials of waste cooking oil in static state and constant flow rate through near-infrared spectroscopy. Two to four kinds of raw materials of waste cooking oil (soybean oil, canola oil, sunflower seed oil, and olive oil) were mixed with combination of different ratio. The NIR absorbance of the samples was measured 3 times repeatedly by placing them in a cuvette having a light transmission distance of 12 mm between the halogen light source and NIR spectrometer in the wavelength range of 898.677 to 2132.65nm. These absorption spectrum were used to execute PLSR(Partial Least Squares Regression) on each raw material of waste cooking oil concentration via The Unscrambler (ver. 9.7, CAMO Software, Norway). As a result, 14 PLS models were generated, showing high linearity and low prediction error of R²_cal>0.946, R²_val>0.896, RMSEC<0.348, RMSEV<0.496. It was confirmed that the absorption spectrum of mixed waste cooking oil was estimated and the content of each raw material could be measured. It is expected that applying near-infrared spectrometer and PLS model to biodiesel production process for the production of biodiesel using waste cooking oil will greatly contribute to the improvement of biodiesel yield.
Figures & Tables
Fig. 1. Esterification process of producing biodiesel.