Enhancement of CO۲ mass transfer using SiO۲ nanoparticles in an aqueous a-MDEA solution for CO۲ absorption process

This study investigates the effect of adding SiO۲ nanoparticles to the amine solution on the mass transfer coefficients with the aim to obtain effective solvent in the CO۲ capturing process. An aqueous mixture of the methyl di-ethanol amine (MDEA), activated by blending with Piperazine (PZ) (a-MDEA), was considered as base absorption solvent. The addition of SiO۲ nanoparticles with six different concentrations to the base absorption solvent was then studied. The absorption process took place in an agitated batch reactor at ۴۰ ºC. Considering the gas pressure drop in the reactor the CO۲ absorption and mass transfer rates were obtained for all types of the solvents and were compared with each other. Results revealed that two regimes of fast and slow were involved in the CO۲ absorption process, where the overall mass transfer of the fast regime was more than ۱۰۰ times that of the slow one. The results indicated that the liquid phase controlled the mass transfer in the CO۲ absorption process. Furthermore, the maximum increase in the absorption rate was happenned when the concentration of SiO۲ nanoparticles was set at ۲۵ ppm in the solvent. In this regard, the enhancement was at least ۸۵% increase in the overall mass transfer coefficient. The findings of this study can be used to design new nanoparticle-based solvents and reduce the cost of the CO۲ capturing process.

Keywords:

CO۲ absorption , CO۲ gas mass transfer , Nano-solvent , Piperazine , SiO۲ nanoparticles