Equilibrium Measurements of the NH3-CO2-H2O System: Speciation Based on Raman Spectroscopy and Multivariate Modeling

Abstract EN

Liquid speciation is important for reliable process design and optimization of gas-liquid absorption process.

Liquid-phase speciation methods are currently available, although they involve tedious and time-consuming laboratory work.

Raman spectroscopy is well suited for in situ monitoring of aqueous chemical reactions.

Here, we report on the development of a method for speciation of the CO2-NH3-H2O equilibrium using Raman spectroscopy and PLS-R modeling.

The quantification methodology presented here offers a novel approach to provide rapid and reliable predictions of the carbon distribution of the CO2-NH3-H2O system, which may be used for process control and optimization.

Validation of the reported speciation method which is based on independent, known, NH3-CO2-H2O solutions shows estimated prediction uncertainties for carbonate, bicarbonate, and carbamate of 6.45 mmol/kg H2O, 34.39 mmol/kg H2O, and 100.9 mmol/kg H2O, respectively.