Estimation of Volatile Organic Compound Mass Transfer Coefficients in the Vacuum Desorption of Acetone from Activated Carbon

摘要

The export concentrations of acetone desorption from activated carbon at different temperatures, vacuum degrees, and saturated adsorption capacities were measured. The results showed that the greater the desorption vacuum degree and the initial adsorption capacity, the smaller the desorption rate. Given the adsorbent microporous capillary effect and the mass transfer in the process of desorption, the concentration curve reflects three phases, which are the vacuum-concentrated phase, fast attenuation phase, and slow attenuation phase. Through theoretical analysis and a coupled model of the desorption process, numerical simulation of the acetone desorption from activated carbon was carried out. Experimental and theoretical analysis showed that small temperature changes were caused by desorption; therefore, the change of the mass transfer coefficient and concentration caused by the temperature change is also small. In different desorption phases, a coupled effect on the mass transfer coefficients have different influences on the concentration curve. For the same initial adsorption capacity, the greater the partial pressure of the acetone, the larger the mass transfer coefficient. Obtaining the mass transfer coefficient and axial dispersion coefficient by sections can make the numerical results coincide well with the experimental data, and the axial diffusion coefficient should not be ignored in vacuum desorption.