IMPROVEMENT OF CO2 ABSORPTION USING AL2O3 NANOFLUIDS IN A STIRRED THERMOSTATIC REACTOR

The improvement of CO2 absorption by Al2O3 nanofluids with deionized water as the base fluid was studied experimentally. The reactor used was a stirred thermostatic reactor, operated batchwise. Pure CO2 was employed in all the experiments. The content of Al2O3 in nanofluids ranged from 0 to 0.2 % (wt). Sodium dodecyl benzene sulfonate (SDBS) was employed to improve the stability of the nanofluids, and the combined effect of nanoparticles and surfactants on the absorption enhancement was studied. The parameters such as the concentration of Al2O3 nanoparticles and surfactants, the stirring speed, and the ultrasonic time were varied. The results show that the nanoparticle mass fraction and the ultrasonic time have an optimum value for the CO2 absorption enhancement. The combination of surfactants and nanoparticles improves the enhancement performance of Al2O3 nanofluids more effectively than that without surfactants. With the increase of the stirring speed, the effective absorption ratio in stable nanofluids declines, while in poorly dispersed Al2O3 suspensions, it is increased first and then reduced. The mechanism of the Al2O3 nanofluid enhancing CO2 absorption is discussed accordingly. The absorption enhancement by the Al2O3 nanofluid is mainly attributable to convective motion induced by the Brownian motion.