(430f) Rate Phenomena In the Reaction of Hydrogen Sulfide with a Pelletized Zinc Oxide–Based Sorbent

Zinc oxide is an exceptionally effective sorbent for hydrogen sulfide.  This oxide exhibits high affinity for hydrogen sulfide and consequently has been explored to remove sulfur from gasoline and diesel transportation fuels and from Claus sulfur plant tail-gas.

This study focuses on a zinc oxide-based solid sorbent for sorption of H₂S from dilute gas streams.  A zinc oxide-based sorbent containing 65% zinc oxide, 18% peptized alumina and 17% perlite was prepared by wet pelletizing the solid reactants, drying the product at 150°C for one hour and heating the solids at 635°C for one hour.  After cooling, the solids were crushed, dry sieved, wet sieved, and redried at 150°C for an hour to produce the sorbent.  

The sorption of hydrogen sulfide was measured as a function of time with a thermogravimetric analyzer.  Sorption rate is shown as a function of hydrogen sulfide partial pressure, temperature, sorbent granule particle size, and sorbent granulation method.  In addition the capabilities of sorbent regeneration are explored.

A model for this system indicates that rate is governed by hydrogen sulfide transport through a growing zinc sulfide product layer in particles which constitute the agglomerated sorbent.  The pelletized sorbent prepared in the present study reacts at a higher rate than a similar sorbent previously prepared by spray drying.