Two phase hydroprocessing

Information

  • Patent Grant
  • 6428686
  • Patent Number
    6,428,686
  • Date Filed
    Thursday, June 22, 2000
    24 years ago
  • Date Issued
    Tuesday, August 6, 2002
    22 years ago
Abstract
A process where the need to circulate hydrogen through the catalyst is eliminated. This is accomplished by mixing and/or flashing the hydrogen and the oil to be treated in the presence of a solvent or diluent in which the hydrogen solubility is “high” relative to the oil feed. The type and amount of diluent added, as well as the reactor conditions, can be set so that all of the hydrogen required in the hydroprocessing reactions is available in solution. The oil/diluent/hydrogen solution can then be fed to a plug flow reactor packed with catalyst where the oil and hydrogen react. No additional hydrogen is required, therefore, hydrogen recirculation is avoided and trickle bed operation of the reactors is avoided. Therefore, the large trickle bed reactors can be replaced by much smaller tubular reactor.
Description




BACKGROUND OF THE INVENTION




The present invention is directed to a two phase hydroprocessing process and apparatus, wherein the need to circulate hydrogen gas through the catalyst is eliminated. This is accomplished by mixing and/or flashing the hydrogen and the oil to be treated in the presence of a solvent or diluent in which the hydrogen solubility is high relative to the oil feed. The present invention is also directed to hydrocracking, hydroisomerization and hydrodemetalization.




In hydroprocessing which includes hydrotreating, hydrofinislling, hydrorefining and hydrocracking, a catalyst is used forreacting hydrogen with a petroleum fraction. distillates or resids, for the purpose of saturating or removing sulfur, nitrogen, oxygen, metals or other contaminants, or for molecular weight reduction (cracking). Catalysts having special surface properties are required in order to provide the necessary activity to accomplish the desired reaction(s).




In conventional hydroprocessing it is necessary to transfer hydrogen from a vapor phase into the liquid phase where it will be available to react with a petroleum molecule at the surface of the catalyst. This is accomplished by circulating very large volumes of hydrogen gas and the oil through a catalyst bed. The oil and the hydrogen flow through the bed and the hydrogen is absorbed into a thin film of oil that is distributed over the catalyst. Because the amount of hydrogen required can be large, 1000 to 5000 SCF/bbl of liquid, the reactors are very large and can operate at severe conditions, from a few hundred psi to as much as 5000 psi, and temperatures from around 400° F.-900° F.




A conventional system for processing is shown in U.S. Pat. No. 4,698,147, issued to McConaghy, Jr. on Oct. 6, 1987 which discloses a SHORT RESIDENCE TIME HYDROGEN DONOR DILUENT CRACKING PROCESS. McConaghy '147 mixes the input flow with a donor diluent to supply the hydrogen for the cracking process. After the cracking process the mixture is separated into product and spent diluent, and the spent diluent is regenerated by partial hydrogenation and returned to the input flow for the cracking step. Note that McConaghy '147 substantially changes the chemical nature of the donor diluent during the process in order to release the hydrogen necessary for cracking. Also, the McConaghy '147 process is limited by upper temperature restraints due to coil coking, and increased light gas production, which sets an economically imposed limit on the maximum cracking temperature of the process.




U.S. Pat. No. 4,857,168, issued to Kubo et al. on Aug. 15, 1989 discloses a METHOD FOR HYDROCRACKING HEAVY FRACTION OIL. Kubo '168 uses both a donor diluent and hydrogen gas to supply the hydrogen for the catalyst enhanced cracking process. Kubo '168 discloses that a proper supply of heavy fraction oil, donor solvent, hydrogen gas, and catalyst will limit the formation of coke on the catalyst, and the coke formation may be substantially or completely eliminated. Kubo '168 requires a cracking reactor with catalyst and a separate hydrogenating reactor with catalyst. Kubo '168 also relies on the breakdown of the donor diluent for supply hydrogen in the reaction process.




The prior art suffers from the need to add hydrogen gas and/or the added complexity of rehydrogenating the donor solvent used in the cracking process. Hence there is a need for an improved and simplified hydroprocessing method and apparatus.




BRIEF SUMMARY OF THE INVENTION




In accordance with the present invention, a process has been developed wherein the need to circulate hydrogen gas through the catalyst is eliminated. This is accomplished by mixing and/or flashing the hydrogen and the oil to be treated in the presence of a solvent or diluent in which the hydrogen solubility is “high” relative to the oil feed so that the hydrogen is in solution.




The type and amount of diluent added, as well as the reactor conditions can be set so that all of the hydrogen required in the hydroprocessing reactions is available in solution. The oil/diluent/hydrogen solution can then be fed to a reactor such as a plug flow or tubular reactor packed with catalyst where the oil and hydrogen react. No additional hydrogen is required, therefore, the hydrogen recirculation is avoided and the trickle bed operation of the reactor is avoided. Therefore, the large trickle bed reactors can be replaced by much smaller reactors (see

FIGS. 1

,


2


and


3


).




The present invention is also directed to hydrocracking, hydroisomerization, hydrodemetalization, and the like. As described above, hydrogen gas is mixed and/or flashed together with the feedstock and a diluent such as recycled hydrocracked product, isomerized product, or recycled demetaled product so as to place hydrogen in solution, and then the mixture is passed over a catalyst.




A principle object of the present invention is the provision of an improved two phase hydroprocessing system, process, method, and/or apparatus.




Another object of the present invention is the provision of an improved hydrocracking, hydroisomerization, Fischer-Tropsch and/or hydrodemetalization process.




Other objects and further scope of the applicability of the present invention will become apparent from the detailed description to follow, taken in conjunction with the accompanying drawings, wherein like parts are designated by like reference numerals.











BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING





FIG. 1

is a schematic process flow diagram of a diesel hydrotreater.





FIG. 2

is a schematic process flow diagram of a resid hydrotreater.





FIG. 3

is a schematic process flow diagram of a hydroprocessing system.





FIG. 4

is a schematic process flow diagram of a multistage reactor system.





FIG. 5

is a schematic process flow diagram of a 1200 BPSD hydroproccssing unit.











DETAILED DESCRIPTION OF THE INVENTION




We have developed a process where the need to circulate hydrogen gas or a separate hydrogen phase through the catalyst is eliminated. This is accomplished by mixing and/or flashing the hydrogen and the oil to be treated in the presence of a solvent or diluent having a relatively high solubility for hydrogen so that the hydrogen is in solution.




The type and amount of diluent added, as well as the reactor conditions can be set so that all of the hydrogen required in the hydroprocessing reactions is available in solution. The oil/diluent/hydrogen solution can then be fed to a plug flow, tubular or other reactor packed with catalyst where the oil and hydrogen react. No additional hydrogen is required therefore, hydrogen recirculation is avoided and the trickle bed operation of the reactor is avoided. Hence, the large trickle bed reactors can be replaced by much smaller or simpler reactors (see

FIGS. 1

,


2


and


3


).




In addition to using much smaller or simpler reactors, the use of a hydrogen recycle compressor is avoided. Because all of the hydrogen required for the reaction is made available in solution ahead of the reactor there is no need to circulate hydrogen gas within the reactor and no need for the recycle compressor. Elimination of the recycle compressor and the use of, for example, plug flow or tubular reactors greatly reduces the capital cost of the hydrotreating process.




Most of the reactions that take place in hydroprocessing are highly exothermic and as a result a great deal of heat is generated in the reactor. The temperature of the reactor can be controlled by using a recycle stream. A controlled volume of reactor effluent can be recycled back to the front of the reactor and blended with fresh feed and hydrogen. The recycle stream absorbs some of the heat and reduces the temperature rise through the reactor. The reactor temperature can be controlled by controlling the fresh feed temperature and the amount of recycle. In addition, because the recycle stream contains molecules that have already reacted, it also serves as an inert diluent.




One of the biggest problems with hydroprocessing is catalyst coking. Because the reaction conditions can be quite severe cracking can take place on the surface of the catalyst. If the amount of hydrogen available is not sufficient, the cracking can lead to coke formation and deactivate the catalyst. Using the present invention for hydroprocessing, coking can be nearly eliminated because there is always enough hydrogen available in solution to avoid coking when cracking reactions take place. This can lead to much longer catalyst life and reduced operating and maintenance costs.





FIG. 1

shows a schematic process flow diagram for a diesel hydrotreater generally designated by the numeral


10


. Fresh feed stock


12


is pumped by feed charge pump


14


to combination area


18


. The fresh feed stock


12


is then combined with hydrogen


15


and hydrotreated feed


16


to form fresh feed mixture


20


. Mixture


20


is then separated in separator


22


to form first separator waste gases


24


and separated mixture


30


. Separated mixture


30


is combined with catalyst


32


in reactor


34


to form reacted mixture


40


. The reacted mixture


40


is split into two product flows, recycle flow


42


and continuing flow


50


. Recycle flow


42


is pumped by recycle pump


44


to become the hydrotreated feed


16


which is combined with the fresh feed


12


and hydrogen


15


.




Continuing flow


50


flows into separator


52


where second separator waste gases


54


are removed to create the reacted separated flow


60


. Reacted separated flow


60


then flows into flasher


62


to form flasher waste gases


64


and reacted separated flashed flow


70


. The reacted separated flashed flow


70


is then pumped into stripper


72


where stripper waste gases


74


are removed to form the output product


80


.





FIG. 2

shows a schematic process flow diagram for a resid hydrotreater generally designated by the numeral


100


. Fresh feed stock


110


is combined with solvent


112


at combination area


114


to form combined solvent-feed


120


. Combined solvent-feed


120


is the pumped by solvent-feed charge pump


122


to combination area


124


. The combined solvent-feed


120


is then combined with hydrogen


126


and hydrotreated feed


128


to form hydrogen-solvent-feed mixture


130


. Hydrogen-solvent-feed mixture


130


is then separated in first separator


132


to form first separator waste gases


134


and separated mixture


140


. Separated mixture


140


is combined with catalyst


142


in reactor


144


to form reacted mixture


150


. The reacted mixture


150


is split into two product flows, recycle flow


152


and continuing flow


160


. Recycle flow


152


is pumped by recycle pump


154


to become the hydrotreated feed


128


which is combined with the solvent-feed


120


and hydrogen


126


.




Continuing flow


160


flows into second separator


162


where second separator waste gases


164


are removed to create the reacted separated flow


170


. Reacted separated flow


170


then flows into flasher


172


to form flasher waste gases


174


and reacted separated flashed flow


180


. The flasher waste gases


174


are cooled by condenser


176


to form solvent


112


which is combined with the incoming fresh feed


110


.




The reacted separated flashed flow


180


then flows into stripper


182


where stripper waste gases


184


are removed to form the output product


190


.





FIG. 3

shows a schematic process flow diagram for a hydroprocessing unit generally designated by the numeral


200


.




Fresh feed stock


202


is combined with a first diluent


204


at first combination area


206


to form first diluent-feed


208


. First diluent-feed


208


is then combined with a second diluent


210


at second combination area


212


to form second diluent-feed


214


. Second diluent-feed


214


is then pumped by diluent-feed charge pump


216


to third combination area


218


.




Hydrogen


220


is input into hydrogen compressor


222


to make compressed hydrogen


224


. The compressed hydrogen


224


flows to third combination area


218


.




Second diluent-feed


214


and compressed hydrogen


224


are combined at third combination area


218


to form hydrogen-diluent-feed mixture


226


. The hydrogen-diluent-feed mixture


226


then flows though feed-product exchanger


228


which warms the mixture


226


, by use of the third separator exhaust


230


, to form the first exchanger flow


232


. First exchanger flow


232


and first recycle flow


234


are combined at forth combination area


236


to form first recycle feed


238


.




The first recycle feed


238


then flows though first feed-product exchanger


240


which warms the mixture


238


, by use of the exchanged first rectifier exchanged exhaust


242


, to form the second exchanger flow


244


. Second exchanger flow


244


and second recycle flow


246


are combined at fifth combination area


248


to form second recycle feed


250


.




The second recycle feed


250


is then mixed in feed-recycle mixer


252


to form feed-recycle mixture


254


. Feed-recycle mixture


254


then flows into reactor inlet separator


256


.




Feed-recycle mixture


254


is separated in reactor inlet separator


256


to form reactor inlet separator waste gases


258


and inlet separated mixture


260


. The reactor inlet separator waste gases


258


are flared or otherwise removed from the present system


200


.




Inlet separated mixture


260


is combined with catalyst


262


in reactor


264


to form reacted mixture


266


. Reacted mixture


266


flows into reactor outlet separator


268


.




Reacted mixture


266


is separated in reactor outlet separator


268


to form reactor outlet separator waste gases


270


and outlet separated mixture


272


. Reactor outlet separator waste gases


270


flow from the reactor outlet separator


268


and are then flared or otherwise removed from the present system


200


.




Outlet separated mixture


272


flows out of reactor outlet separator


268


and is split into large recycle flow


274


and continuing outlet separated mixture


276


at first split area


278


.




Large recycle flow


274


is pumped through recycle pumps


280


to second split area


282


. Large recycle flow


274


is split at combination area


282


into first recycle flow


234


and second recycle flow


246


which are used as previously discussed.




Continuing outlet separated mixture


276


leaves first split area


278


and flows into effluent heater


284


to become heated effluent flow


286


.




Heated effluent flow


286


flows into first rectifier


288


where it is split into first rectifier exhaust


290


and first rectifier flow


292


. First rectifier exhaust


290


and first rectifier flow


292


separately flow into second exchanger


294


where their temperatures difference is reduced.




The exchanger transforms first rectifier exhaust


290


into first rectifier exchanged exhaust


242


which flows to first feed-product exchanger


240


as previously described. First feed-product exchanger


240


cools first rectifier exchanged exhaust


242


even further to form first double cooled exhaust


296


.




First double cooled exhaust


296


is then cooled by condenser


298


to become first condensed exhaust


300


. First condensed exhaust


300


then flows into reflux accumulator


302


where it is split into exhaust


304


and first diluent


204


. Exhaust


304


is exhausted from the system


200


. First diluent


204


flows to first combination area


206


to combine with the fresh feed stock


202


as previously discussed.




The exchanger transforms first rectifier flow


292


into first rectifier exchanged flow


306


which flows into third separator


308


. Third separator


308


splits first rectifier exchanged flow


306


into third separator exhaust


230


and second rectified flow


310


.




Third separator exhaust


230


flows to exchanger


228


as previously described. Exchanger


228


cools third separator exhaust


230


to form second cooled exhaust


312


.




Second cooled exhaust


312


is then cooled by condenser


314


to become third condensed exhaust


316


. Third condensed exhaust


316


then flows into reflux accumulator


318


where it is split into reflux accumulator exhaust


320


and second diluent


210


. Reflux accumulator exhaust


320


is exhausted from the system


200


. Second diluent


210


flows to second combination area


212


to rejoin the system


200


as previously discussed.




Second rectified flow


310


flows into second rectifier


322


where it is split into third rectifier exhaust


324


and first end flow


326


. First end flow


326


then exits the system


200


for use or further processing. Third rectifier exhaust


324


flows into condenser


328


where it is cooled to become third condensed exhaust


330


.




Third condensed exhaust


330


flows from condenser


328


into fourth separator


332


. Fourth separator


332


splits third condensed exhaust


330


into fourth separator exhaust


334


and second end flow


336


. Fourth separator exhaust


334


is exhausted from the system


200


. Second end flow


336


then exits the system


200


for use or further processing.





FIG. 4

shows a schematic process flow diagram for a 1200 BPSD hvdroprocessing unit generally designated by the numeral


400


.




Fresh feed stock


401


is monitored at first monitoring point


402


for acceptable input parameters of approximately 260° F., at 20 psi, and 1200 BBL/D. Tile fresh feed stock


401


is then combined with a diluent


404


at first combination area


406


to form combined diluent-feed


408


. Combined diluent-feed


408


is the pumped by diluent-feed charge pump


410


through first monitoring orifice


412


and first valve


414


to second combination area


416


.




Hydrogen


420


is input at parameters of 100° F., 500 psi, and 40000 SCF/HR into hydrogen compressor


422


to make compressed hydrogen


424


. The hydrogen compressor


422


compresses the hydrogen 420 to 1500 psi. The compressed hydrogen


424


flows through second monitoring point


426


where it is monitored for acceptable input parameters. The compressed hydrogen


424


flows through second monitoring orifice


428


and second valve


430


to second combination area


416


.




First monitoring orifice


412


, first valve


414


, and FFIC


434


are connected to FIC


432


which controls the incoming flow of combined diluent-feed


408


to second combination area


416


. Similarly, second monitoring orifice


428


, second valve


430


, and FIC


432


are connected to FFIC


434


which controls the incoming flow of compressed hydrogen


424


to second combination area


416


. Combined diluent-feed


408


and compressed hydrogen


424


are combined at second combination area


416


to form hydrogen-diluent-feed mixture


440


. The mixture parameters arc approximately 1500 psi and 2516 BBL/D which are monitored at fourth monitoring point


442


. The hydrogen-diluent-feed mixture


440


then flows though feed-product exchanger


444


which warms the hydrogen-diluent-feed mixture


440


, by use of the rectified product


610


, to form the exchanger flow


446


. The feed-product exchanger


444


works at approximately 2.584 MMBTU/HR.




The exchanger flow


446


is monitored at fifth monitoring point


448


to gather information about the parameters of the exchanger flow


446


.




The exchanger flow


446


then travels into the reactor preheater


450


which is capable of heating the exchange flow


446


at 5.0 MMBTU/HR to create the preheated flow


452


. Preheated flow


452


is monitored at sixth monitoring point


454


and by TIC


456


.




Fuel gas


458


flows though third valve


460


and is monitored by PIC


462


to supply the fuel for the reactor preheater


450


. PIC


462


is connected to third valve


460


and TIC


456


.




Preheated flow


452


is combined with recycle flow


464


at third combination area


466


to form preheated-recycle flow


468


. Preheated-recycle flow


468


is monitored at seventh monitoring point


470


. The preheated-recycle flow


468


is then mixed in feed-recycle mixer


472


to form feed-recycle mixture


474


. Feed-recycle mixture


474


then flows into reactor inlet separator


476


. The reactor inlet separator


476


has parameters of 60″ I.D.


×10′ 0″S/S.






Feed-recycle mixture


474


is separated in reactor inlet separator


476


to form reactor inlet separator waste gases


478


and inlet separated mixture


480


. Reactor inlet separator waste gases


478


flow from the reactor inlet separator


476


through third monitoring orifice


482


which is connected to FI


484


. The reactor inlet separator waste gases


478


then travel through fourth valve


486


, past eighth monitoring point


488


and are then flared or otherwise removed from the present system


400


.




LIC


490


is connected to both fourth valve


486


and reactor inlet separator


476


.




Inlet separated mixture


480


flows out of the reactor inlet separator


476


with parameters of approximately 590° F. and 1500 psi which are monitored at ninth monitoring point


500


.




Inlet separated mixture


480


is combined with catalyst


502


in reactor


504


to form reacted mixture


506


. Reacted mixture


506


is monitored by TIC


508


and at tenth monitoring point


510


for processing control. The reacted mixture


506


has parameters of 605° F. and 1450 psi as it flows into reactor outlet separator


512


.




Reacted mixture


506


is separated in reactor outlet separator


512


to form reactor outlet separator waste gases


514


and outlet separated mixture


516


. Reactor outlet separator waste gases


514


flow from the reactor outlet separator


512


through monitor


515


for PIC


518


. The reactor outlet separator waste gases


514


then travel past eleventh monitoring point


520


and through fifth valve


522


and are then flared or otherwise removed from the present system


400


.




The reactor outlet separator


512


is connected to controller LIC


524


. The reactor outlet separator


512


has parameters of 60″ I.D.×


10′-0″ S/S.






Outlet separated mixture


516


flows out of reactor outlet separator


512


and is split into both recycle flow


464


and continuing outlet separated mixture


526


at first split area


528


.




Recycle flow


464


is pumped through recycle pumps


530


and past twelfth monitoring point


532


to fourth monitoring orifice


534


. Fourth monitoring orifice


534


is connected to FIC


536


which is connected to TIC


508


. FIC


536


controls sixth valve


538


. After the recycle flow


464


leaves fourth monitoring orifice


534


, the flow


464


flows through sixth valve


538


and on to third combination area


466


where it combines with preheated flow


452


as previously discussed.




Outlet separated mixture


526


leaves first split area


528


and flows through seventh valve


540


which is controlled by LIC


524


. Outlet separated mixture


526


then flows past thirteenth monitoring point


542


to effluent heater


544


.




Outlet separated mixture


526


then travels into the effluent heater


544


which is capable of heating the outlet separated mixture


526


at 3.0 MMBTU/HR to create the heated effluent flow


546


. The heated effluent flow


546


is monitored by TIC


548


and at fourteenth monitoring point


550


. Fuel gas


552


flows though eighth valve


554


and is monitored by PIC


556


to supply the fuel for the effluent heater


544


. PIC


556


is connected to eighth valve


554


and TIC


548


.




Heated effluent flow


546


flows from fourteenth monitoring point


550


into rectifier


552


. Rectifier


552


is connected to LIC


554


. Steam


556


flows into rectifier


552


through twentieth monitoring point


558


. Return diluent flow


560


also flows into rectifier


552


. Rectifier


552


has parameters of 42″ I.D.


×54′-0″ S/S.






Rectifier diluent


562


flows out of rectifier


552


past monitors for TIC


564


and past fifteenth monitoring point


566


. Rectifier diluent


562


then flows through rectifier ovhd, condenser


568


. Rectifier ovhd, condenser


568


uses flow CWS/R


570


to change rectifier diluent


562


to form condensed diluent


572


. Rectifier ovhd, condenser


568


has parameters of 5.56 MMBTU/HR.




Condensed diluent


572


then flows into rectifier reflux accumulator


574


. Rectifier reflux accumulator


574


has parameters of 42″ I.D.×10′-0″ S/S. Rectifier reflux accumulator


574


is monitored by LIC


592


. Rectifier reflux accumulator


574


splits the condensed diluent


572


into three streams: drain stream


576


, gas stream


580


, and diluent stream


590


.




Drain stream


576


flows out of rectifier reflux accumulator


574


and past monitor


578


out of the system


400


.




Gas stream


580


flows out of rectifier reflux accumulator


574


, past a monitoring for PlC


582


, through ninth valve


584


, past fifteenth monitoring point


586


and exits the system


400


. Ninth valve


584


is controlled by PIC


582


.




Diluent stream


590


flows out of rectifier reflux accumulator


574


, past eighteenth monitoring point


594


and through pump


596


to form pumped diluent stream


598


. Pumped diluent stream


598


is then split into diluent


404


and return diluent flow


560


at second split area


600


. Diluent


404


flows from second split area


600


, through tenth valve


602


and third monitoring point


604


. Diluent


404


then flows from third monitoring point


604


to first combination area


406


where it combines with fresh feed stock


401


as previously discussed.




Return diluent flow


560


flows from second split area


600


, past nineteenth monitoring point


606


, through eleventh valve


608


and into rectifier


552


. Eleventh valve


608


is connected to TIC


564


.




Rectified product


610


flows out of rectifier


552


, past twenty first monitoring point


612


and into exchanger


444


to form exchanged rectified product


614


. Exchanged rectified product


614


then flows past twenty second monitoring point


615


and through product pump


616


. Exchanged rectified product


614


flows from pump


616


through fifth monitoring orifice


618


. Sixth monitoring orifice


618


is connected to FI


620


. Exchanged rectified product then flows from sixth monitoring orifice


618


to twelfth valve


622


. Twelfth valve


622


is connected to LIC


554


. Exchanged rectified product


614


then flows from twelfth valve


622


through twenty third monitoring point


624


and into product cooler


626


where it is cooled to form final product


632


. Product Cooler


626


uses CWS/R


628


. Product cooler has parameters of 0.640 MMBTU/HR. Final product


632


flows out of cooler


626


, past twenty fourth monitoring point


630


and out of the system


400


.





FIG. 5

shows a schematic process flow diagram for a multistage hydrotreater generally designated by the numeral


700


. Feed


710


is combined with hydrogen


712


and first recycle stream


714


in area


716


to form combined feed-hydrogen-recycle stream


720


. The combined feed-hydrogen-recycle stream


720


flows into first reactor


724


where it is reacted to form first reactor output flow


730


. The first reactor output flow


730


is divided to form first recycle stream


714


and first continuing reactor flow


740


at area


732


. First continuing reactor flow


740


flows into stripper


742


where stripper waste gases


744


such as H


2


S, NH


3


, and H


2


O are removed to form stripped flow


750


.




Stripped flow


750


is then combined with additional hydrogen


752


and second recycle stream


754


in area


756


to form combined stripped-hydrogen-recycle stream


760


. The combined stripped-hydrogen-recycle stream


760


flows into saturation reactor


764


where it is reacted to form second reactor output flow


770


. The second reactor output flow


770


is divided at area


772


to form second recycle stream


754


and product output


780


.




In accordance with the present invention, deasphalting solvents include propane, butanes, and/or pentanes. Other feed diluents include light hydrocarbons, light distillates, naptha, diesel, VGO, previously hydroprocessed stocks, recycled hydrocracked product, isomerized product, recycled demetaled product, or the like.




EXAMPLE 1




A feed selected from the group of petroleum fractions, distillates, resids, waxes, lubes, DAO, or fuels other than diesel fuel is hydrotreated at 620 K to remove sulfur and nitrogen. Approximately 200 SCF of hydrogen must be reacted per barrel of diesel fuel to make specification product. The diluent is selected from the group of propane, butane, pentane, light hydrocarbons, light distillates, naptha, diesel, VG


0


, previously hydroprocessed stocks, or combinations thereof A tubular reactor operating at 620 K outlet temperature with a 1/1 or 2/1 recycle to feed ratio at 65 or 95 bar is sufficient to accomplish the desired reactions.




EXAMPLE 2




A feed selected from the group of petroleum fractions, distillates, resids, oils, waxes, lubes, DAO, or the like other than deasphalted oil is hydrotreated at 620 K to remove sulfur and nitrogen and to saturate aromatics. Approximately 1000 SCF of hydrogen must be reacted per barrel of deasphalted oil to make specification produce. The diluent is selected from the group of propane, butane, pentane, light hydrocarbons, light distillates, naptha, diesel. VG


0


, previously hydroprocessed stocks, or combinations thereof. A tubular reactor operating at a 620 K outlet temperature and 80 bar with a recycle ratio of 2.5/1 is sufficient to provide all of the hydrogen required and allow for a less than 20 K temperature rise through the reactor.




EXAMPLE 3




A two phase hydroprocessing method and apparatus as described and shown herein.




EXAMPLE 4




In a hydroprocessing method, the improvement comprising the step of mixing and/or flashing the hydrogen and the oil to be treated in the presence of a solvent or diluent in which the hydrogen solubility is high relative to the oil feed.




EXAMPLE 5




The Example 4 above wherein the solvent or diluent is selected from the group of heavy naptha, propane, butane, pentane, light hydrocarbons, light distillates, naptha diesel, VG


0


, previously hydroprocessed stocks, or combinations thereof.




EXAMPLE 6




The Example 5 above wherein the feed is selected from the group of oil, petroleum fraction, distillate, resid, diesel fuel, deasphalted oil, waxes, lubes, and the like.




EXAMPLE 7




A two phase hydroprocessing method comprising the steps of blending a feed with a diluent, saturating the diluent/feed mixture with hydrogen ahead of a reactor reacting the feed/diluent/hydrogen mixture with a catalyst in the reactor to saturate or remove sulphur, nitrogen, oxygen, metals, or other contaminants, or for molecular weight reduction or cracking.




EXAMPLE 8




The Example 7 above wherein the reactor is kept at a pressure of 500-5000 psi, preferably 1000-3000 psi.




EXAMPLE 9




The Example 8 above further comprising the step of running the reactor at super critical solution conditions so that there is no solubility limit.




EXAMPLE 10




The Example 9 above further comprising the step of removing heat from the reactor affluent, separating the diluent from the reacted feed, and recycling the diluent to a point upstream of the reactor.




EXAMPLE 11




A hydroprocessed, hydrotreated, hydrofinished, hydrorefined, hydrocracked, or the like petroleum product produced by one of the above described Examples.




EXAMPLE 12




A reactor vessel for use in the improved hydrotreating process of the present invention includes catalyst in relatively small tubes of 2-inch diameter, with an approximate reactor volume of 40 ft.


3


, and with the reactor built to withstand pressures of up to about only 3000 psi.




EXAMPLE 13




In a solvent deasphalting process eight volumes of n butane are contacted with one volume of vacuum tower bottoms. After removing the pitch but prior to recovering the solvent from the deasphalted oil (DAO) the solvent/DAO mix is pumped to approximately 1000-1500 psi and mixed with hydrogen, approximately 900 SCF H


2


per barrel of DAO. The solvent/DAO/H


2


mix is heated to approximately 590K-620K and contacted with catalyst for removal of sulfur, nitrogen and saturation of aromatics. After hydrotreating the butane is recovered from the hydrotreated DAO by reducing the pressure to approximately 600 psi.




EXAMPLE 14




At least one of the examples above including multi-stage reactors, wherein two or more reactors are placed in series with the reactors configured in accordance with the present invention and having the reactors being the same or different with respect to temperature, pressure, catalyst, or the like.




EXAMPLE 15




Further to Example 14 above, using multi-stage reactors to produce specialty products, waxes, lubes, and the like.




Briefly, hydrocracking is the breaking of carbon-carbon bonds and hydroisomerization is the rearrangement of carbon-carbon bonds. Hydrodemetalization is the removal of metals, usually from vacuum tower bottoms or deasphalted oil, to avoid catalyst poisoning in cat crackers and hydrocrackers.




EXAMPLE 16




Hydrocracking: A volume of vacuum gas oil is mixed with 1000 SCF H


2


per barrel of gas oil feed and blended with two volumes of recycled hydrocracked product (diluent) and passed over a hydrocracking catalyst of 750° F. and 2000 psi. The hydrocracked product contained 20 percent naphtha, 40 percent diesel and 40 percent resid.




EXAMPLE 16




Hydroisomerization: A volume of feed containing 80 percent paraffin wax is mixed with 200 SCF H


2


per barrel of feed and blended with one volume if isomerized product as diluent and passed over an isomerization catalyst at 550° F. and 2000 psi. The isomerized product has a pour point of 30° F. and a VI of 140.




EXAMPLE 18




Hydrodemetalization: A volume of feed containing 80 ppm total metals is blended with 150 SCF H


2


per barrel and mixed with one volume of recycled demetaled product and passed over a catalyst at 450° F. and 1000 psi. The product contained 3 ppm total metals.




Generally, Fischer-Tropsch refers to the production of paraffins from carbon monoxide and hydrogen (CO & H


2


or synthesis gas). Synthesis gas contains CO


2


, CO,H


2


and is produced from various sources, primarily coal or natural gas. The synthesis gas is then reacted over specific catalysts to produce specific products.




Fischer-Tropsch synthesis is the production of hydrocarbons, almost exclusively paraffins, from CO and H


2


over a supported metal catalyst. The classic Fischer-Tropsch catalyst is iron, however other metal catalysts are also used.




Synthesis gas can and is used to produce other chemicals as well, primarily alcohols, although these are not Fischer-Tropsch reactions. The technology of the present invention can be used for any catalytic process where one or more components must be transferred from the gas phase to the liquid phase for reaction on the catalyst surface.




EXAMPLE 19




A two stage hydroprocessing method, wherein the first stage is operated at conditions sufficient for removal of sulfur, nitrogen, oxygen, and the like (620 K, 100 psi), after which the contaminants H


2


S, NH


3


and water are removed and a second stage reactor is then operated at conditions sufficient for aromatic saturation.




EXAMPLE 20




The process as recited in at least one of the examples above, wherein in addition to hydrogen, carbon monoxide (CO) is mixed with the hydrogen and the mixture is contacted with a Fischer-Tropsch catalyst for the synthesis of hydrocarbon chemicals.




In accordance with the present invention, an improved hydroprocessing, hydrotreating, hydrofinishing, hydrorefining, and/or hydrocracking process provides for the removal of impurities from lube oils and waxes at a relatively low pressure and with a minimum amount of catalyst by reducing or eliminating the need to force hydrogen into solution by pressure in the reactor vessel and by increasing the solubility for hydrogen by adding a diluent or a solvent. For example, a diluent for a heavy cut is diesel fuel and a diluent for a light cut is pentane. Moreover, while using pentane as a diluent, one can achieve high solubility. Further, using the process of the present invention one can achieve more than a stoichiometric requirement of hydrogen in solution. Also, by utilizing the process of the present invention, one can reduce cost of the pressure vessel and can use catalyst in small tubes in the reactor and thereby reduce cost. Further, by utilizing the process of the present invention, one may be able to eliminate the need for a hydrogen recycle compressor.




Although the process of the present invention can be utilized in conventional equipment for hydroprocessing, hydrotreating, hydrofinishing, hydrorefining and/or hydrocracking, one can achieve the same or a better result using lower cost equipment, reactors, hydrogen compressors, and the like by being able to run the process at a lower pressure, and/or recycling solvent, diluent, hydrogen, or at least a portion of the previously hydroprocessed stock or feed.



Claims
  • 1. A hydroprocessing method comprising:combining a liquid feed with reactor effluent and flashing with hydrogen, then separating any gas from the liquid upstream of the reactor and then contacting the feed/effluent/hydrogen mixture with a catalyst in the reactor, removing the contacted liquid from the reactor at an intermediate position, combining the removed liquid with hydrogen gas to resaturate with hydrogen, separating the gas from the liquid and reintroducing the removed liquid back into the reactor at the point the removed liquid was withdrawn.
  • 2. The method of claim 1, wherein liquid from the reactor is introduced into a second reactor containing a different catalyst.
  • 3. A hydroprocessing method for treating an oil feed with hydrogen in a reactor, comprising:mixing and flashing the hydrogen and oil feed to be treated in the presence of a solvent or diluent wherein the percentage of hydrogen in solution is greater than the percentage of hydrogen in the feed to form a liquid feed/diluent/hydrogen mixture, then separating any gas from the liquid mixture upstream of the reactor, and then contacting the liquid feed/diluent/hydrogen mixture with a catalyst in the reactor to at least one of remove contaminants and saturate aromatics.
  • 4. The method as recited in claim 3 wherein the solvent or diluent is selected from the group of heavy naphtha, propane, butane, pentane, light hydrocarbons, light distillates, naphtha, diesel, VGO, previously hydroprocessed stocks, or combinations thereof.
  • 5. The method as recited in claim 4 wherein the feed is selected from the group of oil, petroleum fraction, distillate, resid, diesel fuel, deasphalted oil, waxes, lubes, and specialty products.
  • 6. A hydroprocessing method comprising blending a feed with a diluent, saturating the diluent/feed mixture with hydrogen ahead of a reactor to form a liquid feed/diluent/hydrogen mixture, separating any excess gas from the liquid mixture ahead of the reactor, and then contacting the liquid feed/diluent/hydrogen mixture with a catalyst in the reactor to remove at least one of sulphur, nitrogen, oxygen, metals, and combinations thereof.
  • 7. The method as recited in claim 6, wherein the reactor is kept at a pressure of 500-5000 psi.
  • 8. The method as recited in claim 7, further comprising the step of running the reactor at super critical solution conditions so that there is no solubility limit.
  • 9. The method as recited in claim 6, wherein the process is a multi-stage process using a series of two or more reactors.
  • 10. The method as recited in claim 8, further comprising the step of removing heat from the reactor effluent, separating the diluent from the reacted feed, and recycling the diluent to a point upstream of the reactor.
  • 11. The method as recited in claim 6, wherein multiple reactors arc used to remove at least one of sulphur, nitrogen, oxygen, metals, and combinations thereof and then to saturate aromatics.
  • 12. The method as recited in claim 6, wherein a portion of the reacted feed is recycled and mixed with the blended feed ahead of the reactor.
  • 13. The method as recited in claim 9, wherein a first stage is operated at conditions sufficient for removal of sulfur, nitrogen, and oxygen contaminants from the feed, at least 620 K, 100 psi, after which, the contaminant H2S, NH3 and water are removed and a second stage reactor is then operated at conditions sufficient for aromatic saturation of the processed feed.
  • 14. The method as recited in claim 13, wherein in addition to hydrogen, CO (carbon monoxide) is mixed with the hydrogen and the resultant liquid feed/diluent/hydrogen/CO mixture is contacted with a Fischer-Tropsch catalyst in the reactor for the synthesis of hydrocarbon chemicals.
  • 15. The method as recited in claim 3, wherein in addition to hydrogen, CO (carbon monoxide) is mixed with the hydrogen and the resultant feed/diluent/hydrogen/CO mixture is contacted with a Fischer-Tropsch catalyst in the reactor for the synthesis of hydrocarbon chemicals.
  • 16. The method as recited in claim 6, wherein in addition to hydrogen, CO (carbon monoxide) is mixed with the hydrogen and the resultant feed/diluent/hydrogen/CO mixture is contacted with a Fischer-Tropsch catalyst in the reactor for the synthesis of hydrocarbon chemicals.
  • 17. The method as recited in claim 6, wherein the reactor is kept at a pressure of 1000-3000 psi.
  • 18. The method as recited in claim 1, wherein the reactor is kept at a pressure of 500-5000 psi.
  • 19. The method as recited in claim 1, wherein the reactor is kept at a pressure of 1000-3000 psi.
  • 20. The method as recited in claim 1, further comprising the step of running the reactor at super critical solution conditions so that there is no solubility limit.
  • 21. The method as recited in claim 1, wherein the process is a multi-stage process using a series of two or more reactors.
  • 22. The method as recited in claim 20, further comprising removing heat from the reactor effluent, separating diluent from the reacted feed, recycling the diluent to a point upstream of the reactor.
  • 23. The method as recited in claim 1, wherein multiple reactors are used to remove at least one of sulphur, nitrogen, oxygen, metals, and combinations thereof and then to saturate aromatics.
  • 24. The method as recited in claim 1, wherein a portion of the reacted feed is recycled and mixed with the blended feed ahead of the reactor.
  • 25. The method as recited in claim 21, wherein the first stage is operated at conditions sufficient for removal of sulfur, nitrogen, and oxygen contaminants from the feed, at least 620 K, 100 psi, after which, the contaminant H2S, NH3 and water are removed and a second stage reactor is then operated at conditions sufficient for aromatic saturation of the processed feed.
  • 26. The method as recited in claim 1, wherein multiple reactors are used for molecular weight reduction.
  • 27. The method as recited in claim 1, wherein multiple reactors are used for cracking.
  • 28. The method as recited in claim 12, wherein said recycled and mixed reacted feed reduces the temperature rise through the reactor.
  • 29. The method as recited in claim 24, wherein said recycled and mixed reacted feed reduces the temperature rise through the reactor.
  • 30. The method as recited in claim 12, wherein the recycle ratio is about 1/1 to 2.5/1 based on volume.
  • 31. The method as recited in claim 24, wherein the recycle ratio is about 1/1 to 2.5/1 based on volume.
CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of and is a continuation of U.S. patent application, Ser. No. 09/104,079, now U.S. Pat. No. 6,123,835, filed Jun. 24, 1998, which is a continuation-in-part of U.S. provisional application, Ser. No. 60/050,599, filed Jun. 24, 1997, now abandoned.

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Provisional Applications (1)
Number Date Country
60/050599 Jun 1997 US
Continuations (1)
Number Date Country
Parent 09/104079 Jun 1998 US
Child 09/599913 US