Adsorption of Volatile Organic Compounds on Fluidized Activated Carbon Bed

Background: Fixed bed adsorber as a controlling method for volatile organic compounds is widely used. However, these adsorbers are facing some issues such as high pressure drop, non-uniformed distribution of fluid, channeling and blockage. Fluidized bed adsorber as a novel method solves lots of these limitations. Objectives: This research aimed at investigating factors affecting the adsorption of vapors of VOCs on fluidized bed adsorbers. Materials and Methods: To assess adsorption, an annular fluidized bed reactor was designed and charged with activated carbon particles with size of 50 - 100 and 100 - 140 American society for testing and materials(ASTM) standard mesh, respectively. To calculate the minimum fluidization velocity, Ergun equation was used. The effect of inlet concentration (400 - 600 ppmv), fluidization velocity, particle size distribution and breakthrough time were investigated under a steady state. Results: Tests indicated that by increasing flow rate from 0.3 (L/min), bubbles formed in the bed and the bed's pressure drop suddenly declined. The adsorption test indicated that, when Q = 3 (L/min), the removal efficiency of activated carbon (AC) (100 - 140 mesh ASTM), was nearly 100% up to 99 min and it reached zero after 260 min. For 50 -100 Mesh AC, the removal efficiency was close to 100% up to 95 min and it reached zero after 270 Minutes. The results also indicated that increasing initial concentration and flow rate reduces breakthrough time. However, two flow rates, 2 and 3 (L/min) Comparison, did not reveal significant differences in the removal efficiency of the bed before breakthrough time. Conclusions: Results indicated that annular fluidized bed reactor's adsorbers are useful techniques for VOCs adsorption. Comparison of two particle ranges indicates that in all concentrations and all flow rates of the experiments, smaller particle size adsorption are better. In superficial velocity above the minimum fluidization velocity, pressure drop of fluidized beds are less than the pressure drop of fixed beds. So fluidized bed systems are more applicable for smaller adsorber particles.