(281g) Effects of Regenerated Monolithic Catalysts on Removal of Hydrogen Sulfide in Coal Gases

Coal gases contain mainly CO, H₂,
CO₂, moisture, H₂S, and other contaminants.  Hydrogen sulfide
in coal gases is required to be removed prior to utilizing coal gases for
various purposes such as power generation and hydrogen production.

Monolithic catalysts for the development of a single-step
sulfur recovery process are used to remove H₂S from coal gases in
this study. Sulfur dioxide is used as an oxidizer to convert H₂S
into liquid element sulfur.  Monolithic catalysts, wash-coated with gamma
alumina oxide, are impregnated with various metal promoters to increase removal
of H₂S
from coal gases and decrease formation of COS.  

H₂S in coal gases is reacted with SO₂ to remove H₂S from coal
gases.   This heterogeneous catalytic reaction has heterogeneous products such
as liquid elemental sulfur and steam on active sites of catalysts.  Some of
produced liquid elemental sulfur is attached to porous structure of catalysts,
and poison catalysts.  Deactivated catalysts are regenerated by removing liquid
elemental sulfur with nitrogen at elevated temperatures.

Effects of catalyst age on conversion of H₂S
to elemental sulfur and formation of COS and  various regeneration
methods of catalysts poisoned with liquid elemental sulfur are described in
this presentation.  Performances of regenerated catalysts are presented in
terms of H₂S removal capacity and selectivity of COS at various
reactor operation conditions.