Real-Time FTIR-ATR Spectroscopy for Monitoring Ethanolysis: Spectral Evaluation, Regression Modelling, and Molecular...

Area of Science:

• Chemical Engineering
• Analytical Chemistry
• Process Monitoring

Background:

• Rising demand for biodiesel necessitates efficient industrial-scale reaction monitoring.
• Existing methods for monitoring ethanolysis lack real-time capability and simplicity.
• Accurate online monitoring is crucial for optimizing transesterification and ensuring product quality.

Purpose of the Study:

• To develop a straightforward online monitoring system for the ethanolysis reaction in biodiesel production.
• To enable real-time assessment of reaction progress without sample pretreatment.
• To validate the system's performance under diverse industrial reaction conditions.

Main Methods:

• Development of simple linear regression (SLR) and multiple linear regression (MLR) models.
• Utilizing Fourier transform infrared spectroscopy (FTIR) with a continuous flow cell for data acquisition.
• Employing gas chromatography (GC) as the reference method for reaction mixture characterization.
• Correlation analysis to identify relevant spectral regions for regression modeling.

Main Results:

• Achieved real-time ethanolysis monitoring using FTIR and linear regression models.
• Demonstrated SLR performance comparable to complex partial least squares (PLS) regression (RMSEP = 2.11).
• Validated the system across a range of temperatures (40-60 °C) and catalyst concentrations (0.25-1.0% NaOH).

Conclusions:

• The developed online monitoring system provides an efficient and accurate method for tracking biodiesel ethanolysis.
• The system effectively identifies dynamic process changes and confirms compliance with EU ester content regulations.
• This approach offers a practical solution for real-time quality control in industrial biodiesel production.