Intensification of Sono-Assisted CO2 Stripping/Carbon-Rich Solvent Regeneration by Fe2O3 Hydrophobic Micronized Particles

Abstract

In 2020, the amount of CO2 generated by coal combustion was estimated to be 15.32 Gt CO2. In a solvent-based postcombustion CO2 capture (PCCC) process, the solvent regeneration/CO2 stripping process uses thermal energy to regenerate the solvent. It has an adverse impact on the solvent’s thermal stability, besides causing a significant quantity of solvent loss and a high energy demand. In recent times, one method for PCCC cost savings has emerged: sono-assisted solvent regeneration/CO2 stripping. The present work focuses on enhancing the high-frequency ultrasound-assisted aqueous carbon-rich 30 wt % monoethanolamine (MEA) solvent regeneration/CO2 stripping process using Fe2O3 hydrophobic micronized particles (concentrations varied in the ranges of 0.005, 0.01, 0.05, 0.1, and 0.2 wt %) in a controlled-temperature environment at 12 °C using 360 kHz, 470 kHz, and 1 MHz (streaming-dominant frequencies). From the investigation, the lowest concentration (0.005 wt %) of micronized particles shows maximum enhancements of 12.29, 20.93, and 33.62%, thereby decreasing the solvent sensible energy requirements by 1.26, 2.4, and 2.9 times than without micronized particles for the tested frequencies. In addition, the observed CO2 stripping rate is much higher when compared to the case without micronized particles. The stripping efficiency is observed to be high in the initial stages of sonication (5 min).