Experimental investigation of CO2 removal using Piperazine solution in a stirrer bubble column

In the present work, absorption of carbon dioxide into Piperazine solution was investigated experimentally in a pilot scale stirrer bubble column. In the experiments, mass transfer and hydrodynamics parameters including loading, removal efficiency, absorption flux and mass transfer coefficients at various volumetric liquid and CO2 flow rate, absorbent concentration, and stirrer speed were studied. The experiments were carried out at 295.15 K temperature and atmospheric pressure under the Piperazine concentration in range of 0.1-0.5 mol l−1, CO2 partial pressure range 16.0-35.2 kPa, stirrer speed range in range of 0-300 rpm and liquid flow rate in range of 0.5-2.0 l h−1.The results showed that mass transfer flux, overall mass transfer coefficient, driving force and CO2removal efficiency were varied in the range of (6.18-15.99) × 10−6 kmol m−2 s−1, (2.39-2.58) × 10−6 kmol m−2 s−1 kPa−1, 200-1400 Pa, and 65.5-82.1%, respectively. The hydrodynamics studies indicate that the gas holdups and the Sauter mean diameter in the bubble column increase with increasing CO2 partial pressure. CO2 partial pressure influence depends on the Piperazine concentration. This positive influence of partial pressure emanates from the smaller bubbles formation. Also increasing the CO2 partial pressure in the range of 16.0-35.2 kPa, increases the gas holdup and Sauter mean diameter up to about 48%.