(225a) Heel Formation During Adsorption-Desorption of VOCs on Honeycomb Zeolite: Effect of Regeneration Parameters

Cyclic adsorption and regeneration are process commonly used to abate emissions of volatile organic compounds (VOCs). Honeycomb zeolite adsorbents offer several advantages over conventional packed bed adsorbents, due to their ability to accommodate large flows with low pressure drop. Heel buildup, i.e., the accumulation of strongly or permanently adsorbed species in the pores of the adsorbent, can be a challenge for cyclic adsorption as it decreases the adsorbent lifespan and capacity which increases the cost of emission abatement.

The objective of this study is to investigate the effect of regeneration parameters on heel formation and regeneration efficiency of honeycomb zeolite. Hence, a honeycomb zeolite (ZSM-5 and USY) was used for adsorption of representative polar (isopropanol) and non-polar (1,2,4-trimethylbenzene) VOCs. We investigated the effect, on heel formation, of VOC concentration during adsorption (60, 100, 200, and 400 ppm), regeneration temperature (439, 467, 494, and 522 K), hot air face velocity (1, 1.5, 2, and 3 m/s), and regeneration time (2, 5, 10, and 15 min). A single cycle of adsorption/regeneration was performed for each condition using the Taguchi method to reduce the number of experiments.

The results show that increasing temperature, regeneration time, and hot air flow rate can all contribute to less heel formation. Regeneration time was found to be the single most important operational parameter that influenced heel formation.