Experimental Investigation of the Effect of Nano Heavy Metal Oxide Particles in Piperazine Solution on CO_2 Absorption Using a Stirrer Bubble Column

摘要

In this work, absorption of CO2 into a nanofluid of TiO2, ZnO, and ZrO2 in piperazine solution was investigated experimentally in a continuous stirrer bubble column. The dosage range of nanofluids was 0.01 to 0.1 wt% in the experiments. The process parameters, such as nanoparticles type, solid loading, and stirrer speed, were varied to the hydrodynamics and absorption performance, including gas holdup, Sauter mean diameter, CO2 loading, CO2 removal efficiency, absorption rate, mass transfer flux, and overall mass transfer coefficients. The results showed that the nanoparticle mass fraction and range of stirrer speed have an optimum value for the above-mentioned performance. The optimum value of TiO2, ZnO, and ZrO2 nanoparticles were 0.05, 0.1, and 0.05 wt%, respectively. The maximum absorption rate of TiO2, ZnO, and ZrO2 compared with that of pure Pz solution was 14.7% (0.05 wt%), 16.6% (0.1 wt%), and 3.7% (0.05 wt%), respectively. Also, with an increase of the stirring speed, the absorption performance increased first up to 200 rpm and then it starts to decrease after 200 rpm. The hydrodynamics studies indicate that the gas hold-ups increase and the Sauter mean diameter decreases in the bubble column with increasing nanoparticles to the base fluid.