Various novel amine solutions both in aqueous and non-aqueous [monoethylene glycol (MEG)/triethylene glycol(TEG)] forms have been studied for hydrogen sulfide (H₂S) absorption. The study was conducted in a custom build experimental setup at temperatures relevant to subsea operation conditions and atmospheric pressure. Liquid phase absorbed H₂S, and amine concentrations were measured analytically to calculate H₂S loading (mole of H₂S/mole of amine). Maximum achieved H₂S loadings as the function of pKa, gas partial pressure, temperature and amine concentration are presented. Effects of solvent type on absorbed H₂S have also been discussed. Several new solvents showed higher H₂S loading as compared to aqueous N-Methyldiethanolamine (MDEA) solution which is the current industrial benchmark compound for selective H₂S removal in natural gas sweetening process.

A Fourier transform infrared (FTIR) spectroscopy method was developed to identify and quantify various components in an amine-based combined acid gas and water removal process. In this work, an attenuated total reflectance (ATR) probe was used. A partial least-squares (PLS) regression model was also developed using up to four components (methyl diethanolamine (MDEA)-H₂O-CO₂-ethylene glycol/triethylene glycol (MEG/TEG)), and it was successfully validated. The model was applied on thermally degraded CO₂-loaded MDEA blends to predict the weight percentages of MDEA, H₂O, CO₂, and MEG or TEG to test the performance spectrum. The results confirmed that FTIR could be used as a simpler, quicker and reliable tool to identify and quantify various compounds such as MDEA, MEG/TEG, H₂O and CO₂ simultaneously in a combined acid gas and water removal process.

In this study, the thermal stability and corrosivity of various CO₂-loaded tertiary amine blends in both aqueous and non-aqueous form in stainless steel cylinders were studied for combined acid gas and water removal. The thermal stability was measured from the remaining amine concentration and the corrosivity was measured from the amount of various metals in blends using titration and inductively coupled plasma mass spectrometry (ICP-MS), respectively. The experimental data were used to calculate the rate constants of amine group loss. The developed model represented the experimental data very well. Solvent change from H₂O to triethylene glycol (TEG) in blends decreased the thermal stability and vice versa for corrosivity. The amine stability was increased when contact with stainless steel was reduced. An increase in the amine concentration or CO₂ loading at constant temperature decreased the thermal stability and vice versa for corrosivity.

In order to meet future challenges in subsea production and processing compact systems for hydrate control and selective H₂S/CO₂ removal can be used. The development of an amine-based regenerative process whereby both water and H₂S/CO₂ are removed may involve corrosion problems. In this study, the amine stability and corrosion tendencies of 30 wt% aqueous solutions of 2-ethanolamine and N-Methydiethanolamine under high temperatures in presence of MEG/TEG, have been experimentally studied. The results show that the presence of MEG/TEG (in the absence of water) influence both the amine degradation and corrosion. Furthermore, the results indicate that the influence of MEG or TEG is dependent on the amine used.