PROCESS FOR PRODUCTION OF ENVIRONMENTALLY SAFE DIESEL FUEL FROM SULFUR-BEARING OILS Russian patent published in 1999 - IPC

FIELD: petroleum processing and petrochemical processes. SUBSTANCE: fuel is produced by distilling crude oil to isolate kerosene and diesel fractions and catalytic hydrofining of the latter at elevated temperature and hydrogen pressure involving layered charge of aluminum-cobalt-molybdenum and aluminum-nickel-molybdenum catalysts. Process is distinguished by that kerosene and diesel fraction with boiling ranges (160-190)-300 C and (300-310)-390 C, respectively, are isolated and further combined at weight ratio from 70: 30 to 30:70, after which resultant mixture is subjected to hydrofining in presence of, densely arranged in mixture travel direction, catalyst beds: one bed of spherical aluminum-nickel-molybdenum catalyst with grain diameter 2.8- 4.2 mm and two beds of aluminum-cobalt-molybdenum catalyst made in the form of trifolium with diameters 1.8-2.6 and 1.3-1.8 mm, respectively, at weight ratio of the three beds (1.0-1.5):10:(30-35). Catalysts are preliminarily sulfurized with straight-run diesel fraction with shortened end boiling point (no higher than 340 C) and content of sulfur 0.4-1.0 wt %, sulfurization being carried out at gradual temperature rise: to 160-200, 220-240 and 300-340 C and keeping each temperature constant for 2 hr. Hydrofining is carried out at 330-370 C and pressure 2.5-4.0 MPa, liquid space velocity 3.0-4.5 hr^-1. Resulting hydrogenate is stabilized at column top temperature 115-160 C, column bottom temperature 250-320 C, and pressure 0.1-1.2 MPa to produce fraction (160-190)-380 C. EFFECT: increased hydrofining efficiency, increased yield of diesel fuel, and specified technology. 1 tbl