Patent ID: 6596157
Filing Date: 2003-07-22
Classification: C10G

Abstract:
A staged hydrotreating method comprising:(a) contacting a heavy cat naphtha containing sulfur and olefins with a catalytically effective amount of a first hydrotreating catalyst in the presence of hydrogen under non-selective conversion conditions to: (i) remove at least about 95 wt. % sulfur, based on the weight of the sulfur in the heavy cat naphtha and (ii) saturate at least about 50 wt. % olefin, based on the weight of the olefins in the heavy cat naphtha in order to form a hydrotreated heavy cat naphtha at a first temperature; (b) contacting a heated intermediate cat naphtha containing sulfur and olefins at a second temperature with a catalytically effective amount of second hydrotreating catalyst in the presence of hydrogen under selective hydrotreating conditions to (i) remove at least about 95 wt. % of the sulfur, based on the weight of the sulfur in the heated intermediate cat naphtha and (ii) saturate less than about 50 wt. % of the olefins, based on the weight of the olefins present in the heated intermediate cat naphtha in order to form a hydrotreated intermediate cat naphtha at a third temperature greater than the second temperature but less than the first temperature; and(c) heating an intermediate cat naphtha at a fourth temperature, the fourth temperature being less than the second temperature, with the hydrotreated intermediate cat naphtha and with the hydrotreated heavy cat naphtha in order to form the heated intermediate cat naphtha.