(717d) Effect of Temperature and Heating Rate on Heel Build-up during Microwave Regeneration

This study investigates the effect of regeneration temperature and heating rate on irreversible

adsorption of organic vapors typically emitted from automotive painting booths. Two types of beaded

activated carbons (BAC), with different porosities (microporous versus mesoporous) were loaded with

1, 2, 4-trimethylbenzene and regenerated at two regeneration temperatures (288 and 400 ^oC) and at

different heating rates (25, 50, 100, and 150 ^oC/min). The results showed that for the higher

regeneration temperature (400 ^oC), increasing heating rate increased heel build-up by as much as 105%

and 189% for the microporous and mesoporous BACs, respectively. The elevated heel formation at

higher heating rates could be due to adsorbate coking as a result of exposure to high temperature.

Conversely, for the lower regeneration temperature (288 ^oC), increasing the heating rate did not

significantly affect the amount of heel build-up (< 15% and < 5% increase for microporous and

mesoporous BACs, respectively). This could be because the lower regeneration temperature provided

insufficient conditions for coking. The results from this study indicate that the heating rate during

desorption could be optimized to allow fast desorption with minimal adsorbate decomposition.