Experimental investigation on CO2 absorption and physicochemical characteristics of different carbon-loaded aqueous solvents.

Abstract

The anthropogenic carbon dioxide (CO2) denseness in the earth's atmosphere is increasing day-to-day by combusting fossil fuels for power generation. And, it is the most important greenhouse gas (GHG) responsible for 64% of global warming. Solvent-based carbon capture gained more attention towards researchers because of its easiness to integrate with the coal-fired power plant without significant modifications. During CO2 absorption, the physical property of the solvent gets changed. A change in the solvent's physicochemical property affects further CO2 absorption, thereby increasing the carbon-capture energy demand. The present experimental study encompasses CO2 absorption studies using 30 wt% aqueous monoethanolamine (MEA), 2-amino-2-methyl-1-propanol (AMP) and piperazine (PZ) followed by the detailed analysis of physicochemical properties (pH, carbon loading (α), viscosity (μ), density (ρ) and surface tension (σ)) of various CO2-loaded solutions. The results revealed that these properties are exhibiting interdependent eccentrics. Furthermore, an empirical model was developed to predict the carbon loading of the tested solvents. This model includes the tested physicochemical properties, reaction mixture temperature, diffusivity and change in the mass of solvent during carbon loading. In addition, an empirical model for viscosity as a function of temperature, carbon loading and molecular weight of solvents was developed. These models appear to predict the carbon loading and the viscosity well with greater accuracy. Graphical abstract.