Modeling of Drying of Gaseous Mixtures in TSA System with Fixed Bed of Solid Desiccants

Abstract

A nonisothermal, nonequilibrium mathematical model was developed to theoretically analyze adsorptive drying of gaseous mixtures containing water and volatile organic compounds (VOCs). The analysis concerns a four-bed cyclic temperature swing adsorption (TSA) system. The two fixed beds are formed of silica gel primarily as the water vapor adsorbent. The other two consist of activated carbon as the adsorbent of the organic component (e.g., benzene, isopropanol). In the model, possible insignificant interactions among the VOCs and water during adsorption and desorption were neglected. The following parameters were considered to study their effect on the process efficiency: relative humidity of the inlet gas, temperature of the purge gas, and height of the adsorbent beds. Simulation results showed that both the shape of the adsorption isotherm and heat effects played an important role in the breakthrough behavior of water vapor adsorption on silica gel. The model accurately simulated experimental data taken from literature.

Keywords:

• Activated carbon
• Gaseous mixture drying
• Mathematical modeling
• Silica gel
• TSA process

ACKNOWLEDGMENTS

This study was funded by the Polish Ministry of Science and Higher Education under project No. N N209 254938.