Process for the preparation of group ii and group iii lube base oils

Abstract

The preparation of Group II and Group III lube base oils wherein liquid-continuous hydrotreating is used to treat a lube oil raffinate. The hydrotreated lube oil raffinate is then sent to a dewaxing stage that can be either a solvent or catalytic dewaxing stage.

1 . A process for the production of lube base oil, which process comprising:
 i) solvent extracting a lube oil feedstock containing heteroatoms and aromatics and having a viscosity index with an extraction solvent, at solvent extraction conditions, wherein an extract stream and a raffinate stream are produced, and wherein the raffinate stream contains a smaller fraction of heteroatoms and aromatics and has a higher viscosity index than the lube oil feedstock;   ii) hydrotreating at least a portion of said raffinate in the presence of hydrogen and a hydrotreating catalyst under effective hydrotreating conditions in a liquid-continuous reactor to form a hydrotreated raffinate stream; and   iii) dewaxing said hydrotreated raffinate stream under solvent dewaxing conditions in the presence of a dewaxing solvent to obtain a dewaxed lube base oil comprised of at least 90 wt. % saturates, a sulfur content of 0.03 wt. % or less, and a viscosity index of at least 80.   
     
     
         2 . The process of  claim 1  wherein the lube oil feedstock is selected from the group consisting of vacuum gas oils, hydrocracked gas oils, hydrocracked vacuum gas oils, deasphalted oils, reduced crude, vacuum tower bottoms, and deasphalted vacuum resids. 
     
     
         3 . The process of  claim 2  wherein the lube oil feedstock is a vacuum gas oil. 
     
     
         4 . The process of  claim 1  wherein the extraction solvent is selected from the group consisting of N-Methyl-2-pyrrolidone, phenol, or furfural. 
     
     
         5 . The process of  claim 1  wherein the extract from solvent extraction is sent to a solvent recovery step. 
     
     
         6 . The process of  claim 1  wherein a portion of the hydrotreated raffinate is recycled to the liquid-continuous reactor and again hydrotreated with fresh raffinate. 
     
     
         7 . The process of  claim 6  wherein the volume ratio of recycled hydrotreated raffinate to fresh raffinate to the liquid-continuous reactor is from 0.5 to 1 to 5 to 1. 
     
     
         8 . The process of  claim 6  wherein the volume ratio of recycled hydrotreated raffinate to fresh raffinate to the liquid-continuous reactor is from 1 to 1 to 3 to 1. 
     
     
         9 . The process of  claim 1  wherein a portion of the hydrotreated raffinate from the liquid-continuous reactor is withdrawn and saturated with hydrogen then recycled back to the liquid-continuous reactor. 
     
     
         10 . The process of  claim 1  wherein the hydrotreating catalyst is comprised of one or more catalytic metals 
     
     
         11 . The process of  claim 10  wherein the support is selected from the group consisting of alumina, silica, silica alumina, titania, zirconia, and silica-alumina. 
     
     
         12 . The process of  claim 1  wherein the hydrotreating process conditions include temperatures from 400° F. to 800° F. and total pressures from 200 psig to 2200 psig. 
     
     
         13 . The process of  claim 12  wherein the hydrotreating process conditions include temperatures from 600° F. to 750° F. and total pressures from 1000 to 1500 psig. 
     
     
         14 . The process of  claim 1  wherein the raffinate stream, before it is conducted to hydrotreating is sent to a gas-liquid separation stage to remove at least a portion of any excess gas that may be present in the raffinate stream. 
     
     
         15 . The process of  claim 1  wherein the hydrotreated raffinate stream, before it is conducted to dewaxing is sent to a gas-liquid separation stage to remove excess hydrogen and contaminant gases selected from ammonia and hydrogen sulfide and the remaining liquid hydrotreated raffinate stream is sent to solvent dewaxing. 
     
     
         16 . The process of  claim 1  wherein dewaxing solvent is selected from the group consisting of aliphatic ketones having 3 to 6 carbon atoms, low molecular weight hydrocarbons having from 2 to 4 carbon atoms. 
     
     
         17 . The process of  claim 16  wherein the dewaxing solvent is selected from the group consisting of methyl ethyl ketone, methyl isobutyl ketone, propane, butane, and mixtures thereof. 
     
     
         18 . The process of  claim 1  wherein the dewaxing solvent is added to provide a liquid to solids weight ratio of from 5 to 1 to 20 to 1 at dewaxing temperatures from 0 to 50° F. 
     
     
         19 . The process of  claim 1  wherein there catalytic dewaxing is run parallel with solvent dewaxing. 
     
     
         20 . The process of  claim 19  wherein the dewaxed lube base oil is sent to a hydrofinishing zone wherein it is contacted at hydrofinishing conditions with a hydrofinishing catalyst and in the presence of hydrogen to remove at least of portion of any remaining aromatics and to improve color. 
     
     
         21 . A process for the production of lube base oils, which process comprising:
 i) solvent extracting a lube oil feedstock containing heteroatoms and aromatics and having a viscosity index with an extraction solvent, at solvent extraction conditions, wherein an extract stream and a raffinate stream are produced, and wherein the raffinate stream contains a smaller fraction of heteroatoms and aromatics and has a higher viscosity index than the lube oil feedstock;   ii) hydrotreating at least a portion of said raffinate in the presence of hydrogen and a hydrotreating catalyst under effective hydrotreating conditions in a liquid-continuous reactor to form a hydrotreated raffinate stream; and   iii) catalytically dewaxing said hydrotreated raffinate in the presence of hydrogen and a dewaxing catalyst under effective dewaxing conditions including a temperature from 500° F. to 750° F. and a pressure up to 2200 psig and at an effective contact time of feed to catalyst that will remove at least a portion of the waxy paraffinic components by isomerization to less waxy iso-paraffinic components, thereby producing a lube base oil comprised of at least 90 wt. % saturates, less than 0.03 wt. % sulfur and a viscosity index of at least 80.   
     
     
         22 . The process of  claim 21  wherein the lube oil feedstock is selected from the group consisting of vacuum gas oils, hydrocracked gas oils, hydrocracked vacuum gas oils, deasphalted oils, reduced crude, vacuum tower bottoms, and deasphalted vacuum resids. 
     
     
         23 . The process of  claim 21  wherein the lube oil feedstock is a vacuum gas oil. 
     
     
         24 . The process of  claim 21  wherein the extraction solvent is selected from the group consisting of N-Methyl-2-pyrrolidone, phenol, or furfural. 
     
     
         25 . The process of  claim 21  wherein the extract from solvent extraction is sent to a solvent recovery step. 
     
     
         26 . The process of  claim 21  wherein a portion of the hydrotreated raffinate is recycled to the liquid-continuous reactor and again hydrotreated with fresh raffinate. 
     
     
         27 . The process of  claim 26  wherein the volume ratio of recycle hydrotreated raffinate to fresh raffinate to the liquid-continuous reactor is from 0.5 to 1 to 5 to 1. 
     
     
         28 . The process of  claim 27  wherein the volume ratio of recycle hydrotreated raffinate to fresh raffinate to the liquid-continuous reactor is from 1 to 1 to 3 to 1. 
     
     
         29 . The process of  claim 21  wherein a portion of the hydrotreated raffinate from the liquid-continuous reactor is withdrawn and saturated with hydrogen then recycled back to the liquid-continuous reactor. 
     
     
         30 . The process of  claim 21  wherein the hydrotreating catalyst is comprised of one or more catalytic metals selected from Groups VIB and Group VIII of the Periodic Table of the Elements on a refractory support. 
     
     
         31 . The process of  claim 30  wherein the support is selected from the group consisting of alumina, silica, silica alumina, titania, zirconia, and silica-alumina. 
     
     
         32 . The process of  claim 21  wherein the hydrotreating process conditions include temperatures from 400° F. to 800° F. and total pressures from 200 psig to 2200 psig. 
     
     
         33 . The process of  claim 32  wherein the hydrotreating process conditions include temperatures from 600° F. to 750° F. and total pressures from 1000 to 1500 psig. 
     
     
         34 . The process of  claim 21  wherein the raffinate stream, before it is conducted to hydrotreating is sent to a gas-liquid separation stage to remove at least a portion of any excess gas that may be present in the raffinate stream. 
     
     
         35 . The process of  claim 21  wherein the catalytic dewaxing temperature is from 550° F. to 750° F. 
     
     
         36 . The process of  claim 21  wherein the catalytic dewaxing catalyst are selected from the group consisting of crystalline aluminosilicates and silicoaluminophophates. 
     
     
         37 . The process of  claim 36  wherein the catalytic dewaxing catalyst is a crystalline aluminosilicate selected from the group consisting of ZSM-22, ZSM-23, ZSM-35 and ZSM-48, and combinations thereof. 
     
     
         38 . The process of  claim 37  wherein the catalytic dewaxing catalyst contains a binder material selected from the group consisting of alumina, titania, silica, silica-alumina, zirconia, and combinations thereof. 
     
     
         39 . The process of  claim 37  wherein the catalytic dewaxing catalyst contains at least one metal selected from the group consisting of Pt, Pd, and Ni. 
     
     
         40 . The process of  claim 39  wherein the catalytic dewaxing catalyst also contains a metal selected from W and Mo. 
     
     
         41 . The process of  claim 21  wherein the dewaxed lube oil is subjected to hydrofinishing in the presence of hydrogen and a hydrofinishing catalyst at a temperature from 450° F. to 675° F. and total pressures from 400 to 2200 psig. 
     
     
         42 . The process of  claim 41  wherein the hydrofinishing catalyst is comprised of one or more metals selected from Group VIII and Group VI of the Periodic Table of the Elements. 
     
     
         43 . The process of  claim 42  wherein the hydrofinishing catalyst contains at least one metal from Group VIII and at least one metal from Group VIB. 
     
     
         44 . The process of  claim 42  wherein the hydrofinishing catalyst is comprised of a noble metal selected from Pt and Pd on a mesoporous crystalline support. 
     
     
         45 . The process of  claim 44  wherein the mesoporous crystalline support is MCM-41. 
     
     
         46 . A process for upgrading a Group I lube base oil, which process comprising: hydrotreating said Group I lube base oil having less than 90 wt. % saturates and greater than 0.03 wt. % sulfur in the presence of hydrogen and a hydrotreating catalyst under effective hydrotreating conditions in a liquid-continuous reactor to form a hydrotreated lube base oil having a saturate concentration greater than 90 wt. % and a sulfur concentration less than 0.03 wt. %. 
     
     
         47 . The process of  claim 46  wherein a portion of the hydrotreated Group I base oil is recycled to the liquid-continuous reactor and again hydrotreated with fresh Group I base oil. 
     
     
         48 . The process of  claim 46  wherein the volume ratio of recycle hydrotreated Group I base oil to fresh Group I base oil to the liquid-continuous reactor is from 0.5 to 1 to 5 to 1. 
     
     
         49 . The process of  claim 48  wherein the volume ratio of recycle hydrotreated Group I base oil to fresh Group I base oil to the liquid-continuous reactor is from 1 to 1 to 3 to 1. 
     
     
         50 . The process of  claim 46  wherein a portion of the hydrotreated Group I base oil from the liquid-continuous reactor is withdrawn and saturated with hydrogen then recycled back to the liquid-continuous reactor. 
     
     
         51 . The process of  claim 46  wherein the hydrotreating catalyst is comprised of one or more catalytic metals selected from Groups VIB and Group VIII of the Periodic Table of the Elements on a refractory support. 
     
     
         52 . The process of  claim 51  wherein the support is selected from the group consisting of alumina, silica, silica alumina, titania, zirconia, and silica-alumina. 
     
     
         53 . The process of  claim 46  wherein the hydrotreating process conditions include temperatures from 400° F. to 800° F. and total pressures from 200 psig to 2200 psig. 
     
     
         54 . The process of  claim 53  wherein the hydrotreating process conditions include temperatures from 600° F. to 750° F. and total pressures from 1000 to 1500 psig. 
     
     
         55 . The process of  claim 21  wherein the catalytic dewaxing is also performed in a liquid-continuous reactor. 
     
     
         56 . The process of  claim 55  wherein a hydrofinishing step is included which conducted in a liquid-continuous reactor.