Supercritical CO2 desorption of toluene from activated carbon in rotating packed bed

The supercritical CO2 desorption efficiencies of activated carbon loaded with toluene in a rotating packed bed were studied in a temperature range of 305–335 K, a pressure range of 8.96–15.86 MPa, a supercritical CO2 flow rate range of 0.57–4.5 cm3/min, and a rotating speed range of 0–1600 rpm for the particle sizes at 0.3, 0.5, and 1.0 mm. The data show that desorption efficiency was enhanced with increasing rotating speed. For the operation at 315 K, 11.72 MPa, and 1.57 cm3/min, a 100% desorption of toluene from activated carbon at 1600 rpm was achieved at 50 min, but only 68% desorption efficiency was achieved at 60 min in the packed bed without rotation. The significant improvement in desorption was attributed to the presence of centrifugal force. The data also show that the desorption efficiency increased with increasing pressure and CO2 flow rate and decreased with decreasing activated carbon particle size. At low operating pressures, such as 8.96 and 11.72 MPa, desorption at lower temperatures was suggested to achieve a better desorption efficiency. At high operating pressures, such as 15.86 MPa, an optimal desorption temperature, at 315 K, however, was found to exist.