QUANTITATIVE SPECIATION OF THE LIQUID PHASE BY FTIR SPECTROSCOPY IN THE SYSTEM AMP-PZ-CO2-H2O

This work reports a multivariate calibration partial least square regression (PLS) model to quantify the liquid-phase concentrations of 2-amino-2-methyl-1-propanol (AMP), piperazine (PZ), bicarbonate, PZ monocarbamate, and PZ dicarbamate during the absorption/desorption process by Fourier Transform Mid-Infrared spectroscopy (mid-FTIR). The model could predict 33 different concentrations ranging from 0 to 40 wt.% AMP, 0 to 15 wt.% PZ, and 0 to 12 wt.% total CO2 with relative errors lower than 10%, and 87% of the variance of all samples have been represented (R-2), except for PZ dicarbamate. A comparison of a single PLS2 model was made with multiple PLS1 models, one for each chemical species present in the liquid phase. The latter had better predictions and made it possible to differentiate CO2 from its chemical forms, allowing a better understanding of the CO2 capture processes.