Amine Solutions for Biogas Upgrading: Ideal versus Non‐Ideal Absorption Isotherms

Abstract

Amine solutions were applied in carbon dioxide removal from a model mixture of biogas, carried out in a loop reactor system. In addition, the effect of CO 2 absorption acceleration in the presence of piperazine was confirmed and quantified, relating the obtained CO 2 loading with the piperazine concentration. Further, the interactions of CO 2 and water in aqueous amine solutions were discussed. The obtained acid gas loadings were accurately described taking into account the effect of the dissolved CO 2 on the equilibrium constant. A logarithmic absorption isotherm that follows from such considerations and a saturation-type isotherm were compared. In describing the experimental data, advantages and disadvantages of both approaches are discussed.

Mathematical Modeling and Genetic Algorithm Optimization of Reactive Absorption of H2S

“…For this purpose, a tuning coefficient for correlation with the apparent gas‐side mass transfer coefficient is used. Privalova et al 11 also applied a simple logarithmic correlation for the prediction of acid gas loading. The model predictions are compared with experimental data reported by Chen et al 2 and Moussavi et al 7 under similar experimental and operational conditions.…”

Novel Non-aqueous Amine Solvents for Biogas Upgrading

“…We have designed two sets of experiments: (1) CO 2 absorption and, separately, thermal amine regeneration aimed at selecting the most efficient absorbents and (2) continuous cycles of CO 2 absorption−desorption carried out in packed columns with the purpose of verify the efficiency of CO 2 and H 2 S capture. The carbonated species in solution were qualitatively and quantitatively analyzed by 13 (NMR) spectroscopy 27,2 and were found to be originated from the amine and alcohol carbonatation. Until now, non-aqueous solutions of alkanolamines (MEA, DEA, and MDEA) were used for kinetic studies of CO 2 capture.…”

“…To raise its energy content, it is mandatory to upgrade the biogas by means of CO 2 removal. The most common techniques for CO 2 removal are the high-pressure water scrubbing, pressure and thermal swing absorption, physical and chemical capture by organic solvents or amines, and membrane or cryogenic separation. − More recently, metal–organic frameworks (MOFs) are emerging as promising alternatives for CO 2 separation . All of these techniques display both advantages and disadvantages, and their cost to benefit assessment helps to choose the technique for the implementation in a large-scale plant.…”

CO₂ Fixation Using MEA and CaCl₂ Aqueous Solutions

“…Chemical absorption is one of the most effective approaches for CO 2 capture because CO 2 can be satisfactorily removed and the absorbents can be regenerated by heating. Currently, aqueous solutions of alkanolamines have been widely used for the removal of CO 2 from a variety of gas streams [1][2][3][4][5][6][7][8][9][10]. However, the application of this technology was limited due to the very high energy cost in the desorption process.…”