Effect of Moisture on High Temperature H2S Adsorption by Copper-Exchanged Engelhard Titanosilicate-2

The removal of H2S at combustion temperatures can be accomplished using metal oxides which react and sequester H2S as a metal sulfide. Copper-exchanged Engelhard Titanosilicate-2 (Cu-ETS-2) is an ion-exchangeable titanate which has been modified to hold about 17 wt% copper supported on its surface. Cu-ETS-2 has previously been shown to be an effective adsorbent for removing hydrogen sulfide from dry, inert gas streams at temperatures as high as 950 degrees C. This study measured the influence of water vapor on the H2S adsorption capacity of Cu-ETS-2 using an inert stream containing 500 ppm H2S and 10 vol% H2O. The results demonstrate that the presence of water vapor reduces the capacity of the adsorbent at temperatures greater than 350 degrees C. The loss in capacity can be explained by an unexpected increase in the amount of H-2 present in the humid gas stream at elevated temperatures.