Prerefining Process for the Hydrodesulfurization of Heavy Sour Crude Oils to Produce Sweeter Lighter Crudes Using Moving Catalyst System

Abstract

A pre-refining catalytic hydrotreating process for the desulfurization, demetallization, and upgrading of heavy, sour crude oils operating at a moderate temperature and pressure through the utilization of moving catalyst bed technology.

1 . A process for prerefining heavy sour crude oils, the process comprising:
 introducing a heated-pressurized mixture of whole crude oil feedstock and hydrogen into an HDM reaction zone through an HDM reaction inlet, wherein the heated-pressurized mixture is at a first temperature within a range of about 300 to 500° C., wherein the heated-pressurized mixture is at a first pressure within a range of about 30 to 200 bar, wherein the HDM reaction zone further comprises an HDM moving bed, the HDM reaction zone being operable to receive an HDM catalyst through an HDM catalyst inlet, the HDM reaction zone having an HDM catalyst outlet, the HDM catalyst outlet being operable to emit the HDM catalyst from the HDM reaction zone;   introducing the HDM catalyst into the HDM reaction zone through the HDM catalyst inlet;   contacting the premixture with the HDM catalyst within the HDM reaction zone such that the premixture is at least partially demetallized, forming a first effluent, the first effluent being characterized as having 30 to 90% reduced amounts of metals as compared to the whole crude oil feedstock;   introducing the first effluent into an HDM/HDS reaction zone through an HDM/HDS reaction inlet, wherein the HDM/HDS reaction zone further comprises an HDM/HDS moving bed, the HDM/HDS reaction zone being operable to receive an HDM/HDS catalyst through an HDM/HDS catalyst inlet, the HDM/HDS reaction zone having an HDM/HDS catalyst outlet, the HDM/HDS catalyst outlet being operable to emit the HDM/HDS catalyst from the HDM/HDS reaction zone;   introducing the HDM/HDS catalyst into the HDM/HDS reaction zone through the HDM/HDS catalyst inlet;   contacting the first effluent with the HDM/HDS catalyst within the HDM/HDS reaction zone to form a second effluent, wherein the second effluent has a reduced metals and sulfur content as compared to the first effluent;   introducing the second effluent into an HDS reaction zone through an HDS reaction inlet, wherein the HDS reaction zone further comprises an HDS moving bed, the HDS reaction zone being operable to receive an HDS catalyst through an HDS catalyst inlet, the HDS reaction zone having an HDS catalyst outlet, the HDS catalyst outlet being operable to emit the HDS catalyst from the HDS reaction zone;   introducing the HDS catalyst into the HDS reaction zone through the HDS catalyst inlet;   contacting the second effluent with the HDS catalyst within the HDS reaction zone to form a third effluent, wherein the third effluent has a reduced sulfur content as compared to the second effluent;   introducing the third effluent into an HDC reaction zone through an HDC reaction inlet, wherein the HDC reaction zone further comprises an HDC moving bed, the HDC reaction zone being operable to receive an HDC catalyst through an HDC catalyst inlet, the HDC reaction zone having an HDC catalyst outlet, the HDC catalyst outlet being operable to emit the HDC catalyst from the HDC reaction zone;   introducing the HDC catalyst into the HDC reaction zone through the HDC catalyst inlet;   contacting the third effluent with the HDC catalyst within the HDC reaction zone to form a fourth effluent, wherein the fourth effluent is characterized as having an increased API Gravity of at least 1° greater than the whole crude oil feedstock and a reduced amount of metal and sulfur content as compared to the whole crude oil feedstock.   
   
   
       2 . The process of  claim 1 , wherein the first temperature is within a range of about 340 and 390 degrees Celsius. 
   
   
       3 . The process of  claim 1 , wherein the first pressure is in a range of about 30 and 150 bar. 
   
   
       4 . The process of  claim 1 , wherein the HDM catalyst, the HDM/HDS catalyst, and the HDS catalyst comprise at least one metal sulfide selected from the group consisting of sulfides of the group VB, VIB and VIIIB metals supported on an inorganic oxide, wherein the inorganic oxide is selected from the group consisting of alumina, silica alumina, and combinations thereof, wherein the fourth catalyst is in the form of extrudates, spheres, cylinders or pellets or a combination thereof. 
   
   
       5 . The process of  claim 1 , wherein the HDM catalyst, the HDM/HDS catalyst, and the HDS catalyst are selected from the group consisting of Nickel promoting Molybdenum supported on an inorganic oxide, Nickel promoting Tungsten supported on an inorganic oxide, Cobalt promoting Molybdenum supported on an inorganic oxide, Cobalt promoting Tungsten supported on an inorganic oxide, and combinations thereof. 
   
   
       6 . The process of  claim 5 , wherein the inorganic oxide is selected from the group consisting of alumina, silica alumina, and combinations thereof. 
   
   
       7 . The process of  claim 1 , wherein the HDC catalyst comprises a metal selected from the group consisting of sulfides of the group VB, VIB and VIIIB metals on an inorganic oxide, wherein the inorganic oxide is selected from the group consisting of alumina, silica alumina, a zeolite, and combinations thereof, wherein the fourth catalyst is in the form of extrudates, spheres, cylinders, pellets, and combinations thereof. 
   
   
       8 . The process of  claim 1 , wherein each catalyst has a flow rate within its respective moving bed, wherein the flow rate of each of said catalysts is at a rate of approximately 0.5% to 5% of the Tan-Tan height of the reactor per day. 
   
   
       9 . The process of  claim 8 , wherein each of said moving beds can be operated in a co-current or countercurrent fashion. 
   
   
       10 . The process of  claim 1 , wherein the HDM catalyst has a HDM catalyst flow rate, wherein the first effluent has a baseline effluent metal concentration, the process farther comprising monitoring a metal concentration of the first effluent and increasing the HDM catalyst flow rate whenever the metal concentration of the first effluent exceeds the baseline effluent metal concentration. 
   
   
       11 . The process of  claim 1 , wherein the HDM/HDS catalyst has an HDM/HDS catalyst flow rate, wherein the second effluent has a second baseline effluent metal concentration, wherein the second effluent has a baseline sulfur concentration, the process further comprising monitoring a metal concentration and a sulfur concentration of the second effluent and increasing the HDM/HDS catalyst flow rate whenever the metal concentration of the second effluent exceeds the second baseline effluent metal concentration or whenever the sulfur concentration of the second effluent exceeds the baseline sulfur concentration. 
   
   
       12 . The process of  claim 1 , wherein the HDS catalyst has an HDS catalyst flow rate, wherein the third effluent has an HDS baseline sulfur concentration, the process farther comprising monitoring a sulfur concentration of the third effluent and increasing the HDS catalyst flow rate whenever the sulfur concentration of the third effluent exceeds the baseline sulfur concentration. 
   
   
       13 . The process of  claim 1 , wherein the HDC catalyst has an HDC catalyst flow rate, wherein the whole crude oil feedstock and the fourth effluent have a baseline API gravity, the process further comprising monitoring the baseline API gravity of the whole crude oil feedstock and the fourth effluent and increasing the HDC catalyst flow rate whenever the difference between the baseline APT gravity of the fourth effluent and the baseline API gravity of the whole crude oil feedstock does not exceed 1°. 
   
   
       14 . The process of  claim 1 , wherein the third effluent is characterized as having a sulfur content of between 0.1 and 1.0 weight percent. 
   
   
       15 . The process of  claim 1 , further comprising separating the whole crude oil feedstock into two fractions prior to introducing the heated-pressurized mixture into the HDM reaction zone, wherein the first fraction has a maximum boiling point of about 210° C., wherein the second fraction has a minimum boiling point of greater than about 210° C., wherein the first fraction bypasses said reaction zones and is combined with the fourth effluent, wherein the second fraction is mixed with the hydrogen to form the heated-pressurized mixture. 
   
   
       16 . The process of  claim 1 , further comprising:
 introducing a first effluent slip stream to an HDM sampling vessel;   introducing a second effluent slip stream to an HDM/HDS sampling vessel;   introducing a third effluent slip stream to an HDS sampling vessel; and   introducing a fourth effluent slip stream to an HDC sampling vessel, wherein the HDM sampling vessel, the HDM/HDS sampling vessel, the HDS sampling vessel, and the HDC sampling vessel are all operable to allow for sampling of their respective slip streams while the process is in operation.