Performance of gamma-Al2O3 decorated with potassium salts in the removal of CS2 from C5 cracked distillate

Abstract

Deep desulfurization is a key process for the production of high value-added products from C₅ distillates. In this work, different potassium salt modified gamma-Al₂O₃ adsorbents were prepared by an incipient-wetness impregnation method and characterized by N₂ adsorption–desorption, SEM-EDS, TEM, CO₂-TPD, XRD, FT-IR, and IC. The C₅ distillate with a 1200 μg mL⁻¹ sulfur content is desulfurized to less than 10 μg mL⁻¹ within 24 hours by the static adsorption method. For the desulfurization in the fix-bed reactor, the breakthrough sulfur capacity of K₂CO₃-decorated gamma-Al₂O₃ reaches 0.76 wt% under the optimized conditions, viz., at 30 °C, with a sulfur content of 50 μg mL⁻¹ in the raw oil, and a liquid hourly space velocity of 1 h⁻¹. The desulfurization activity of the exhausted adsorbent can be recovered after regeneration. Selective adsorption of CS₂ includes three processes: adsorption, hydrolysis, and oxidation. CS₂ is first adsorbed on the adsorbent and hydrolyzed to form H₂S. H₂S is further oxidized to form S/SO₄²⁻, and then deposits on the surface of the adsorbent. Adsorption, hydrolysis, and oxidation all play essential roles in the removal process of CS₂.