Extending dewaxing cycle length

Abstract

Methods are provided for dewaxing a distillate fuel boiling range feed to improve one or more cold flow properties of the distillate fuel feed, such as cloud point. The dewaxing can be performed in the presence of an olefin co-feed that allows for an increase in the average temperature for exposure of the feed to the dewaxing catalyst. If the dewaxing catalyst is included in a reactor that also includes other hydroprocessing catalyst(s), the olefin co-feed can optionally be introduced into the reactor at a location after the hydroprocessing catalyst bed(s) and prior to the dewaxing catalyst bed(s). Due to the relative ease of performing olefin saturation in the presence of a catalyst with a hydrogenation metal, a substantial portion of the olefins in an olefin co-feed (such as substantially all) can be converted to alkanes. Olefin saturation is exothermic, so the conversion of olefins to alkanes can provide a temperature increase for a feed as it is being exposed to catalyst in a catalyst bed.

1 . A method for producing distillate fuel products, comprising:
 exposing a feed comprising a distillate fuel boiling range fraction and an olefin co-feed to a dewaxing catalyst comprising a crystalline structure having a zeolitic framework and a metal hydrogenation component under effective dewaxing conditions to produce a dewaxed effluent having a cloud point that is reduced relative to a cloud point of the feed by at least 3° C., the feed comprising an organic sulfur content of about 100 wppm or less and having a feed temperature prior to the exposing, the olefin co-feed comprising 0.5 wt % to 20 wt % of C 2 -C 9  olefins based on a weight of the feed, the temperature during the exposing being at least 3° C. greater than the feed temperature.   
     
     
         2 . The method of  claim 1 , wherein the temperature during the exposing is at least 10° C. greater than the feed temperature. 
     
     
         3 . The method of  claim 1 , wherein the effective dewaxing conditions comprise an LHSV of about 1.0 hr −1  to about 10 hr −1  relative to the dewaxing catalyst. 
     
     
         4 . The method of  claim 1 , wherein the olefin co-feed comprises 0.5 wt % to 5 wt % of C 2 -C 4  olefins, or wherein the olefin co-feed comprises 2 wt % to 20 wt % of C 5 -C 9  olefins. 
     
     
         5 . The method of  claim 1 , wherein the effective dewaxing conditions comprise a pressure of from about 200 psig (1.4 MPag) to about 1500 psig (10.4 MPag), a temperature of from about 288° C. to about 440° C., a hydrogen treat gas rate of about 500 scf/bbl (84 Nm 3 /m 3 ) to about 4000 scf/bbl (674 Nm 3 /m 3 ) or less, and a LHSV of from about 0.3 hr −1  to about 10 hr −1  relative to the dewaxing catalyst. 
     
     
         6 . The method of  claim 5 , wherein the effective dewaxing conditions comprise a pressure of at least about 400 psig (˜2.8 MPag) and a temperature of at least about 343° C. 
     
     
         7 . The method of  claim 1 , wherein the feed comprises about 15 wt % or less aromatics. 
     
     
         8 . The method of  claim 1 , further comprising exposing a feedstock comprising an organic sulfur content of 200 wppm to 12000 wppm to a hydrotreating catalyst to form a hydrotreated effluent comprising the distillate fuel boiling range fraction, wherein exposing the feed to a dewaxing catalyst comprises exposing at least a portion of the hydrotreated effluent to the dewaxing catalyst. 
     
     
         9 . The method of  claim 8 , wherein the effective hydrotreating conditions comprise a pressure of from about 200 psig (1.4 MPa) to about 3000 psig (20.7 MPa), a temperature of from about 500° F. (260° C.) to about 800° F. (427° C.), a hydrogen treat gas rate of about 500 SCF/B (84 Nm 3 /m 3 ) to about 10000 SCF/B (1685 Nm 3 /m 3 ) and a space velocity of from about 0.3 hr −1  to about 5.0 hr −1 . 
     
     
         10 . The method of  claim 1 , wherein a) the metal hydrogenation component comprises Pt, Pd, or a combination thereof; b) the zeolitic framework comprises an MRE framework structure, an MTT framework structure, ZSM-48, ZSM-23, or a combination thereof; or c) a combination of a) and b) 
     
     
         11 . The method of  claim 1 , wherein the dewaxing catalyst further comprises a binder, the binder optionally comprising alumina, silica, silica-alumina, titania, zirconia, or a combination thereof. 
     
     
         12 . The method of  claim 1 , wherein the feed has a T5 boiling point of at least about 300° F. (149° C.) and a T95 boiling point of about 800° F. (371° C.) or less, or wherein the feedstock has a T5 boiling point of at least about 300° F. (149° C.) and a T95 boiling point of about 800° F. (371° C.) or less, or a combination thereof. 
     
     
         13 . A method for producing distillate fuel products, comprising:
 exposing a feedstock comprising an organic sulfur content of 200 wppm to 12000 wppm to a hydrotreating catalyst to form a hydrotreated effluent comprising a distillate fuel boiling range fraction, the hydrotreated effluent comprising an effluent temperature an organic sulfur content of 100 wppm or less (or 20 wppm or less or 10 wppm or less); and   exposing at least a portion of the distillate fuel boiling range fraction and an olefin co-feed to a dewaxing catalyst comprising a crystalline structure having a zeolitic framework and a metal hydrogenation component under effective dewaxing conditions to produce a dewaxed effluent having a cloud point that is reduced relative to a cloud point of the feed by at least 2° C. (or at least 5° C., or at least 10° C.), the feed comprising an organic sulfur content of about 100 wppm or less (or about 20 wppm or less, or about 10 wppm or less) and having a feed temperature prior to the exposing, the olefin co-feed comprising 0.5 wt % to 20 wt % of C 2 -C 9  olefins based on a weight of the distillate fuel boiling range fraction, the temperature during the exposing being at least 3° C. greater than the effluent temperature.   
     
     
         14 . The method of  claim 13 , wherein the effective dewaxing conditions comprise an LHSV of about 1.0 hr −1  to about 6.0 hr −1  relative to the dewaxing catalyst. 
     
     
         15 . The method of  claim 13 , wherein the olefin co-feed comprises 1.0 wt % to 4.0 wt % of C 3  olefins, C 4  olefins, or a combination thereof. 
     
     
         16 . The method of  claim 13 , wherein at least a portion of the hydrotreating catalyst and at least a portion of the dewaxing catalyst comprise a catalyst bed. 
     
     
         17 . The method of  claim 13 , wherein the olefin co-feed comprises a portion of an FCC effluent stream comprising C 3  olefins, C 4  olefins, or a combination thereof. 
     
     
         18 . The method of  claim 13 , wherein exposing the feedstock comprising an organic sulfur content to a hydrotreating catalyst comprises exposing the feedstock comprising an organic sulfur content and an olefin co-feed to the hydrotreating catalyst. 
     
     
         19 . A dewaxed effluent comprising about 86 wt % to about 96 wt % of a distillate boiling range fraction relative to a total hydrocarbon content of the dewaxed effluent, about 1 wt % to about 3 wt % of a naphtha boiling range fraction, and about 3 wt % to about 11 wt % of propane, butane, or a combination thereof, the distillate boiling range fraction having a cloud point of −20° C. or less. 
     
     
         20 . The dewaxed effluent of  claim 19 , wherein the dewaxed effluent comprises about 5 wt % to about 10 wt % of propane, butane, or a combination thereof.