Measurement and prediction of desorption behavior of five volatile organic compounds (acetone, n-hexane, methanol, toluene, and n-decane) from activated carbon for supercritical carbon dioxide regeneration

Measurement and prediction of desorption behavior of five volatile organic compounds (VOCs) (acetone, n-hexane, methanol, toluene, and n-decane) from activated carbon by using supercritical carbon dioxide regeneration were studied. Measurements of the desorption behavior were performed with a fixed bed method at temperatures from 313 to 353 K and pressures from 10.0 to 15.0 MPa. The measured desorption rates varied greatly for each VOC, which could be attributed to differences in two properties, affinity of VOCs for activated carbon and the volatility of VOCs. The measured desorption rates increased with increasing pressure and decreasing temperature, which could be explained by increasing CO₂ density. A kinetic model was applied to correlate the desorption behavior. The model demonstrated satisfactory correlations of the desorption behavior with only one fitting parameter. Generalization of the fitting parameter to predict the desorption behavior were also investigated. The proposed prediction model could roughly represent the desorption behavior of VOCs over a wide range of supercritical carbon dioxide conditions.