Abstract
The upgrading of LCO (Light Cycle Oil), which is an aromatic stream from FCC units, has been studied in order to obtain naphtha and medium distillates. The catalysts used have metallic functions of Pd, Pt and Pt-Pd, supported on acid materials of different porous structure and different acidity (HY zeolites, H beta zeolite, amorphous alumina and an FCC catalyst). The experiments have been carried out in an exothermic fixed bed reactor under the following conditions: 350 degrees C; 40-50 bar; H-2/LCO molar ratio (nH(2)), 8.90, 10.00 and 30.23 molH(2) (molLCO)(-1); space velocity (WHSV), 1 and 4 h(-1); time-on-stream, 24 h. The effect of catalyst composition and properties (porous structure and acidity) on conversion, yields of products fractions (dry gases, LPG, naphtha and medium distillates) and selectivity and composition of naphtha and medium distillate fractions has been determined. Pt/Hb catalyst is suitable for maintaining a high selectivity of naphtha (75-80 wt.%) in a range of conversions between 85 and 95 wt.%. Pt/HY catalyst (SiO2/Al2O3 = 5) is the most suitable for producing medium distillates with a selectivity of 65 wt.% for a conversion of 85 wt.%. Pt/HY (SiO2/Al2O3 = 12) catalyst is efficient for obtaining naphtha and medium distillates with a lower content of aromatics. Pt-Pd bimetallic function is interesting for the catalyst to maintain a high conversion at the pseudostable state. (C) 2011 Elsevier Ltd. All rights reserved.