Regeneration of sulfated alumina support in CuO/gamma-Al2O3 sorbent by hydrogen

Abstract

The effects of regeneration temperature, degree of sulfation, and the number of sulfation-regeneration cycle on the regeneration of sulfated CuO/gamma-Al2O3 sorbent have been determined. Sulfates on copper and alumina sites in the sorbent start to be removed by 5 vol % H-2 flow above 300 and 400 degrees C, respectively. From the nonisothermal reduction of the sulfates, the main component of the product gases is SO2. The amount of residual sulfur compound decreases with increasing regeneration temperature up to 450 degrees C, but it remains constant up to 500 degrees C. The pore volume of the regenerated sorbent recovers almost to that of the fresh sorbent at a reduction temperature of 500 degrees C. Sulfation activity of 8 wt % CuO/gamma-Al2O3 sorbent decreases somewhat with the cycles up to 30 times due to degradation of the sorbent at 500 degrees C. On the other hand, the 5 wt % NaCl promoted sorbent is maintained up to 30 cycles at 440 degrees C without degradation of the sorbent.