Hydroprocessing for lubricant basestock production

Abstract

Methods are provided for hydroprocessing a feed (such as hydrotreating, hydrocracking, or hydrofining a feed) to generate a product with a reduced or minimized aromatics content relative to the severity of the hydroprocessing conditions. In some types of hydroprocessing applications, it can be desirable to select the severity of hydroprocessing conditions to achieve a desired level of removal for sulfur, a desired level for removal of nitrogen, and/or a desired level for increasing the viscosity index of a feed. The severity for heteroatom removal and/or viscosity index uplift can also correspond to an amount of conversion of a feed to lower boiling point products, so the lowest severity conditions suitable for achieving a product quality can be desirable. By improving the aromatics saturation during hydroprocessing, the severity of subsequent aromatics saturation processes can be reduced.

What is claimed is: 
     
         1 . A process for selectively hydroconverting a raffinate produced from solvent refining a lubricating oil feedstock, comprising:
 conducting the lubricating oil feedstock to a solvent extraction zone and separating therefrom an aromatics rich extract and a paraffins rich raffinate;   stripping the raffinate of solvent to produce a raffinate feed having a dewaxed oil viscosity index from 80 to 105 and a final boiling point of no greater than 650° C.;   passing the raffinate feed to a first hydroconversion zone and processing the raffinate feed in the presence of a mixed metal catalyst under hydroconversion conditions; and   passing the first hydroconverted raffinate to a second reaction zone and conducting cold hydrofinishing of the first hydroconverted raffinate in the presence of a hydrofinishing catalyst under cold hydrofinishing conditions,   wherein the mixed metal catalyst comprises a sulfided mixed metal catalyst formed by sulfiding a mixed metal catalyst precursor composition, the mixed metal catalyst precursor composition being produced by   a) heating a composition comprising at least one metal from Group 6 of the Periodic Table of the Elements, at least one metal from Groups 8-10 of the Periodic Table of the Elements, and a reaction product formed from (i) a first organic compound containing at least one amine group, and (ii) a second organic compound separate from said first organic compound and containing at least one carboxylic acid group to a temperature from 195° C. to 260° C. for a time sufficient for the first and second organic compounds to form a reaction product in situ that contains an amide moiety, unsaturated carbon atoms not present in the first or second organic compounds, or both;   b) heating a composition comprising one metal from Group 6 of the Periodic Table of the Elements, at least one metal from Groups 8-10 of the Periodic Table of the Elements, and a reaction product formed from (iii) a first organic compound containing at least one amine group and at least 10 carbon atoms or (iv) a second organic compound containing at least one carboxylic acid group and at least 10 carbon atoms, but not both (iii) and (iv), wherein the reaction product contains additional unsaturated carbon atoms, relative to (iii) the first organic compound or (iv) the second organic compound, wherein the metals of the catalyst precursor composition are arranged in a crystal lattice, and wherein the reaction product is not located within the crystal lattice, to a temperature from 195° C. to 260° C. for a time sufficient for the first or second organic compounds to form a reaction product in situ that contains unsaturated carbon atoms not present in the first or second organic compounds; or   c) heating a composition comprising at least one metal from Group 6 of the Periodic Table of the Elements, at least one metal from Groups 8-10 of the Periodic Table of the Elements, and a pre-formed amide formed from (v) a first organic compound containing at least one amine group, and (vi) a second organic compound separate from said first organic compound and containing at least one carboxylic acid group, to form additional in situ unsaturated carbon atoms not present in the first organic compound, the second organic compound, or both, but not for so long that the pre-formed amide substantially decomposes, thereby forming a catalyst precursor containing in situ formed unsaturated carbon atoms.   
     
     
         2 . The process of  claim 1 , further comprising passing the raffinate feed into a second hydroconversion zone and processing the raffinate feed in the presence of a hydroconversion catalyst under second effective hydroconversion conditions, the raffinate feed being passed into the second hydroconversion zone prior to being passed into the first hydroconversion zone or after being passed into the first hydroconversion zone. 
     
     
         3 . The process of  claim 1 , wherein the hydroconversion conditions in the first hydroconversion zone, the second hydroconversion zone, or both the first and second hydroconversion zones include temperatures of from 250° C. to 420° C., hydrogen pressures of from 300 to 3000 psig (2170 to 20786 kPa), liquid hourly space velocities of from 0.1 to 10 hr −1 , and hydrogen treat gas rates of from 500 to 5000 scf/B (89 to 890 m 3 /m 3 ). 
     
     
         4 . The process of  claim 1 , wherein the cold hydrofinishing conditions include temperatures of from 150° C. to 360° C., hydrogen pressures of from 300 to 3000 psig (2170 to 20786 kPa), liquid hourly space velocities of from 0.1 to 10 and hydrogen treat gas rates of from 500 to 5000 scf/B (89 to 890 m 3 /m 3 ). 
     
     
         5 . The process of  claim 1 , wherein solvent in the solvent extraction zone is at least one of furfural, phenol or N-methyl-2-pyrrolidone. 
     
     
         6 . The process of  claim 1 , wherein the cold hydrofinishing step is preceded by or followed by dewaxing, the dewaxing comprising solvent dewaxing under solvent dewaxing conditions, catalytic dewaxing under catalytic dewaxing conditions, or a combination thereof. 
     
     
         7 . The process of  claim 1 , wherein the catalyst precursor composition is treated first with said first organic compound and second with said second organic compound, or wherein the catalyst precursor composition is treated first with said second organic compound and second with said first organic compound, or wherein the catalyst precursor composition is treated simultaneously with said first organic compound and with said second organic compound. 
     
     
         8 . The process of  claim 1 , wherein said at least one metal from Group 6 is Mo, W, or a combination thereof, and wherein said at least one metal from Groups 8-10 is Co, Ni, or a combination thereof. 
     
     
         9 . The process of  claim 1 , wherein the mixed metal catalyst precursor composition is a bulk metal hydroprocessing catalyst precursor composition consisting essentially of the reaction product, an oxide form of the at least one metal from Group 6, an oxide form of the at least one metal from Groups 8-10, and optionally 20 wt % or less of a binder. 
     
     
         10 . A process for producing a lubricating oil feedstock, comprising:
 exposing a feedstock to a mixed metal catalyst under effective hydroprocessing conditions to form a hydroprocessed effluent;   separating the hydroprocessed effluent to form at least a gas phase effluent and a liquid hydroprocessed effluent;   optionally exposing at least a portion of the liquid hydroprocessed effluent to a hydrocracking catalyst under effective hydrocracking conditions to form a hydrocracked effluent;   exposing at least a portion of the optionally hydrocracked effluent to a dewaxing catalyst under effective catalytic dewaxing conditions to form a hydrocracked, dewaxed effluent,   wherein the mixed metal catalyst comprises a sulfided mixed metal catalyst formed by sulfiding a mixed metal catalyst precursor composition, the mixed metal catalyst precursor composition being produced by   a) heating a composition comprising at least one metal from Group 6 of the Periodic Table of the Elements, at least one metal from Groups 8-10 of the Periodic Table of the Elements, and a reaction product formed from (i) a first organic compound containing at least one amine group, and (ii) a second organic compound separate from said first organic compound and containing at least one carboxylic acid group to a temperature from 195° C. to 250° C. for a time sufficient for the first and second organic compounds to form a reaction product in situ that contains an amide moiety, unsaturated carbon atoms not present in the first or second organic compounds, or both;   b) heating a composition comprising one metal from Group 6 of the Periodic Table of the Elements, at least one metal from Groups 8-10 of the Periodic Table of the Elements, and a reaction product formed from (iii) a first organic compound containing at least one amine group and at least 10 carbon atoms or (iv) a second organic compound containing at least one carboxylic acid group and at least 10 carbon atoms, but not both (iii) and (iv), wherein the reaction product contains additional unsaturated carbon atoms, relative to (iii) the first organic compound or (iv) the second organic compound, wherein the metals of the catalyst precursor composition are arranged in a crystal lattice, and wherein the reaction product is not located within the crystal lattice, to a temperature from 195° C. to 250° C. for a time sufficient for the first or second organic compounds to form a reaction product in situ that contains unsaturated carbon atoms not present in the first or second organic compounds; or   c) heating a composition comprising at least one metal from Group 6 of the Periodic Table of the Elements, at least one metal from Groups 8-10 of the Periodic Table of the Elements, and a pre-formed amide formed from (v) a first organic compound containing at least one amine group, and (vi) a second organic compound separate from said first organic compound and containing at least one carboxylic acid group, to form additional in situ unsaturated carbon atoms not present in the first organic compound, the second organic compound, or both, but not for so long that the pre-formed amide substantially decomposes, thereby forming a catalyst precursor containing in situ formed unsaturated carbon atoms.   
     
     
         11 . The process of  claim 10 , wherein the effective hydroprocessing conditions comprise effective hydrotreating conditions, including temperatures of 200° C. to 450° C.; pressures of 250 psig (1.8 MPag) to 5000 psig (34.6 MPag); liquid hourly space velocities (LHSV) of 0.1 hr −1  to 10 hr −1 ; and hydrogen treat rates of 200 scf/B (35.6 m 3 /m 3 ) to 10,000 scf/B (1781 m 3 /m 3 ). 
     
     
         12 . The process of  claim 10 , wherein the effective hydroprocessing conditions comprise second effective hydrocracking conditions, including temperatures of 550° F. (288° C.) to 840° F. (449° C.), hydrogen partial pressures of from 250 psig to 5000 psig (1.8 MPag to 34.6 MPag), liquid hourly space velocities of from 0.05 h −1  to 10 h −1 , and hydrogen treat gas rates of from 35.6 m 3 /m 3  to 1781 m 3 /m 3  (200 SCF/B to 10,000 SCF/B). 
     
     
         13 . The process of  claim 10 , further comprising exposing the feedstock to a hydrotreating catalyst different from the mixed metal catalyst under second effective hydrotreating conditions, the feedstock being exposed to the hydrotreating catalyst prior to the mixed metal catalyst, after the mixed metal catalyst but prior to the separating of the hydroprocessed effluent, or a combination thereof. 
     
     
         14 . The process of  claim 10 , further comprising exposing the feedstock to a hydrocracking catalyst different from the mixed metal catalyst under third effective hydrocracking conditions, the feedstock being exposed to the hydrocracking catalyst prior to the mixed metal catalyst, after the mixed metal catalyst but prior to the separating of the hydroprocessed effluent, or a combination thereof. 
     
     
         15 . The process of  claim 10 , wherein separating the hydroprocessed effluent to form at least a gas phase effluent and a liquid hydroprocessed effluent comprises separating the hydroprocessed effluent to form a hydroprocessed distillate fuel fraction and a higher boiling hydrotreated fraction, the hydroprocessed distillate fuel fraction having a T95 boiling point of 750° F. or less. 
     
     
         16 . The process of  claim 10 , wherein the effective hydrocracking conditions including temperatures of 550° F. (288° C.) to 840° F. (449° C.), hydrogen partial pressures of from 250 psig to 5000 psig (1.8 MPag to 34.6 MPag), liquid hourly space velocities of from 0.05 h −1  to 10 h −1 , and hydrogen treat gas rates of from 35.6 m 3 /m 3  to 1781 m 3 /m 3  (200 SCF/B to 10,000 SCF/B). 
     
     
         17 . The process of  claim 10 , wherein the effective catalytic dewaxing conditions including temperatures of 200° C. to 450° C., hydrogen partial pressures of 1.8 MPag to 34.6 MPag (250 psig to 5000 psig), liquid hourly space velocities of from 0.05 h −1  to 10 h −1 , and hydrogen treat gas rates of 35.6 m 3 /m 3  (200 SCF/B) to 1781 m 3 /m 3  (10,000 scf/B). 
     
     
         18 . The process of  claim 10 , the process further comprising exposing at least a portion of the optionally hydrocracked effluent to a hydrofinishing catalyst under effective hydrofinishing conditions, the effective hydrofinishing conditions including temperatures from 125° C. to 425° C., total pressures from 500 psig (3.4 MPa) to 3000 psig (20.7 MPa), liquid hourly space velocities from 0.1 hr −1  to 5 hr −1  LHSV, and hydrogen treat gas rates of from 500 to 5000 scf/B (89 to 890 m 3 /m 3 ), the at least a portion of the optionally hydrocracked effluent being exposed to the hydrofinishing catalyst prior to the dewaxing catalyst, after the dewaxing catalyst, or a combination thereof. 
     
     
         19 . The process of  claim 10 , the process further comprising exposing at least a portion of the optionally hydrocracked effluent to an aromatic saturation catalyst under effective aromatic saturation conditions, the effective aromatic saturation conditions including temperatures from 200° C. to 425° C., total pressures from 500 psig (3.4 MPa) to 3000 psig (20.7 MPa), liquid hourly space velocities from 0.1 hr −1  to 5 hr −1  LHSV, and hydrogen treat gas rates of from 500 to 5000 scf/B (89 to 890 m 3 /m 3 ), the at least a portion of the optionally hydrocracked effluent being exposed to the aromatic saturation catalyst prior to the dewaxing catalyst, after the dewaxing catalyst, or a combination thereof. 
     
     
         20 . The process of  claim 10 , further comprising separating the optionally hydrocracked, dewaxed effluent to form at least a lubricant boiling range fraction and a distillate boiling range fraction.