Multivariate calibration of CO2 Solubility in iethanolamine (DEA) using Raman Spectroscopy

The emission of greenhouse gas which is mainly from carbon dioxide (CO2)
have cause phenomena of global warming and climate changes. Thus, this issues has
become main focus in worldwide nowadays. CO2 removal process also is an essential
step in many industrial processing especially in natural gas processing. Absorption
based on alkanolamines like diethanolamine (DEA) have been widely applied in
carbon capture plant. CO2 solubility has become an important parameter in the
absorption process for proper process control in plant operation. Measurement of CO2
solubility in 10%, 20% and 30% DEA using Raman spectroscopy is the main focus in
this research. Raman shift and intensity of different DEA concentration with respect
to CO2 loading (mol CO2 / mol amine) are obtained by using Raman spectroscopy.
Partial Least Square (PLS) regression approach will be utilized to develop a calibration
model that relate the Raman spectroscopy data to CO2 solubility in different
concentration of DEA. From the result obtained, 10%, 20% and 30% model have
shown great performance and demonstrate good prediction of CO2 solubility. In
addition, a combined concentration model and combined modified model is developed
to predict CO2 solubility at different DEA concentration. From the study, with the
inverse of 900 – 1100 cm-1 are added to predicting matrix, the validation R2 have been
increased from 0.9004 to 0.9136. Combination of analytical instrument and
multivariate calibration tools will aid the process of online monitoring CO2 solubility
in DEA in process plant operation.