HEAT-TRANSFER IN GRANULAR ACTIVATED CARBON BEDS IN THE PRESENCE OF ADSORBABLE GASES

The thermal conductivity of an active carbon bed in vacuum, helium, ne on and argon has been measured at temperatures up to 200 degrees C. A modified version of the Zehner-Bauer model is developed which successf ully describes the results. The model is expanded to include the varia tion in grain conductivity due to the adsorbed phase when the bed is e xposed to an adsorbable gas. The expanded model is verified by conduct ivity measurements with ammonia at up to 11.3 bar pressure and 25% mas s concentration. Conductivities are predicted to +3.1%, -2.5%. Bed con ductivities with ammonia are typically 0.165 W m(-1) K-1, with minor c hanges due to concentration, but the grain conductivity varies between 0.85 and 1.25 W m(-1) K-1 as a non-linear function of concentration.