Experimental investigation of microwave-assisted regeneration of carbon-rich aqueous solutions

Abstract

Solvent-based post combustion carbon capture is the most prevalent carbon capture technology where 30wt% Monoethanolamine (MEA) is the benchmark solvent used for carbon capture with high energy consumption. Microwave (MW)-assisted carbon-rich solvent regeneration is one of the emerging technologies for CO2 stripping with lesser energy consumption and experimental study covers in these aspects. The factors and levels considered for designing L27 orthogonal array includes nominal power input (10%, 20% and 30% of 800 Watts), regeneration time (5, 15 and 25 min), solvent load (40, 60 and 80 g) and different solvents (30wt% MEA, 20wt% potassium carbonate, and 20wt% piperazine). Physicochemical properties like carbon loading, density, viscosity, surface tension, pH and temperature were tested before and after regeneration. From the experimental investigation, it has been observed that all the physiochemical properties show decreasing trend after the regeneration except pH and temperature. An optimum conditions of lower power level, longer regeneration time and lower solvent loading exhibits better solvent regeneration in the tested conditions. In addition, 20wt% piperazine has the highest regeneration efficiency of 48%. In a cyclic process, the baseline aqueous 30wt% MEA exhibits the lowest regeneration energy of 0.13 kW/mol.CO2 with 24.26% regeneration efficiency for 10% nominal power input.