Adsorptive desulfurization of diesel by regenerable nickel based adsorbents

An experimental investigation on a vapor phase adsorptive desulfurization process for diesel is described based on NiMCM-41 and NiY as sulphur selective adsorbents. Under optimized conditions [pressure 4 bar (absolute) and temperature 350 °C] the NiMCM-41 adsorbent could bring down the sulphur concentration to a 50 ppm level from a concentration of 450 ppm in a refinery diesel, and about 20 ml of diesel could be treated per gram of adsorbent. With a diesel feed of 150 ppm sulphur, the same adsorbent could bring the sulphur down to 15 ppm level and about 14 ml of the feed could be treated per gram of the adsorbent. The performance of NiY is slightly better than NiMCM-41. Around 25 ml diesel feed could be treated per gram NiY adsorbent in bringing down the sulphur levels from 450 ppm to <50 ppm. Both these adsorbents are regenerable under controlled oxidation with air at ∼450 °C without noticeable loss in the sulphur removal capacity. The regeneration conditions were established based on a temperature programmed oxidation (TPO) study on spent diesel adsorbents.