Patent Publication Number: US-9422487-B2

Title: Process for fluid catalytic cracking and hydrocracking hydrocarbons

Description:
BACKGROUND 
     The field of the invention is fluid catalytic cracking (FCC) and hydrocracking. 
     FCC technology, now more than 50 years old, has undergone continuous improvement and remains the predominant source of gasoline production in many refineries. This gasoline, as well as lighter products, is formed as the result of cracking heavier, less valuable hydrocarbon feed stocks such as gas oil. 
     In its most general form, the FCC process comprises a reactor that is closely coupled with a regenerator, followed by downstream hydrocarbon product separation. Hydrocarbon feed contacts catalyst in the reactor to crack the hydrocarbons down to smaller molecular weight products. During this process, coke tends to accumulate on the catalyst which is burned off in the regenerator. 
     The least valuable product from an FCC process is clarified slurry oil (CSO) which is withdrawn from the bottom of the FCC main fractionation column and burned as fuel. The CSO comprises the heaviest product mixed with catalyst particles that have not been successfully removed from the FCC products. Light Cycle Oil (LCO) is also produced in an FCC unit and can be directed to the diesel pool. However, LCO may degrade the quality of the diesel pool due to its high aromaticity and low cetane value. The CSO is less valuable than Light Cycle Oil. Due to operational constraints of FCC main fractionation column, the CSO leaves the main fractionator with an appreciable amount of hydrocarbons in the boiling range of LCO and a small amount in the boiling range of gasoline. Heavy cycle oil (HCO) is an FCC product pumped around to cool the main fractionation column but is not often recovered from the main fractionation column. 
     For FCC units experiencing coking in the main fractionation column bottoms, the main column can be operated at a lower temperature by reducing the flow rate of LCO withdrawn from an LCO side outlet of the main fractionation column and increasing the flow rate of CSO withdrawn from the main fractionation column bottom. The additional LCO in CSO will lower FCC main fractionation column temperature, reduce coking and maintenance on FCC main column bottoms exchangers. However, the refiner who operates with extra LCO in CSO bottoms stream to prevent maintenance issues pays a penalty by losing the additional LCO in the CSO which is not recovered. 
     Hydrocracking is a hydroprocessing process in which hydrocarbons crack at the carbon-carbon bonds in the presence of hydrogen and hydrocracking catalyst to lower molecular weight hydrocarbons. Depending on the desired output, a hydrocracking unit may contain one or more fixed beds of the same or different catalyst. Hydrotreating is a hydroprocessing process in which heteroatoms are removed from hydrocarbons and olefinic compounds are saturated. 
     It would be desirable to recover useful hydrocarbons from CSO. It may also be desirable to upgrade the hydrocarbons recovered from CSO to make quality diesel. 
     SUMMARY OF THE INVENTION 
     In a process embodiment, the invention comprises a process for catalytically cracking hydrocarbons comprising feeding a hydrocarbon feed stream to an FCC reactor and contacting the hydrocarbon feed stream with catalyst to catalytically crack the hydrocarbon feed stream to provide a cracked stream. The catalyst is disengaged from the cracked stream which is fractionated into products including a slurry oil stream from a bottom of a main fractionation column. The slurry oil stream is separated into a cycle oil stream and a heavy stream under vacuum pressure. At least a portion of the cycle oil stream is hydrocracked over hydrocracking catalyst to provide an upgraded stream. 
     In an apparatus embodiment, the invention comprises an apparatus for producing an upgraded product comprising an FCC reactor; a main fractionation column in communication with the FCC reactor and a separator in communication with a main bottoms line of the main fractionation column. A receiver is in communication with a separator overhead line of the separator and a vacuum generating device is in communication with a receiver overhead line of the receiver. A receiver bottoms line of the receiver provides a cycle oil process stream. 
     In an additional process embodiment, the invention comprises a process for recovering catalytically cracked hydrocarbons comprising feeding a hydrocarbon feed stream to an FCC reactor and contacting the hydrocarbon feed stream with catalyst to catalytically crack the hydrocarbon feed stream to provide a cracked stream. The catalyst is disengaged from the cracked stream which is fractionated into products including a slurry oil stream from a bottom of a main fractionation column. The slurry oil stream is separated into a separator overhead stream and a heavy stream under vacuum pressure in a separator. The separator overhead stream is condensed, and the condensed overhead stream is separated in a receiver. A cycle oil stream is recovered from a bottom of the receiver. 
     Advantageously, the process can enable recovery of LCO and/or HCO from CSO to be used as motor fuel or further upgraded to make quality diesel and petrochemicals. 
     Additional features and advantages of the invention will be apparent from the description of the invention, figures and claims provided herein. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic drawing of a FCC unit and a hydrocracking unit. 
         FIG. 2  is schematic drawing of an alternative embodiment of  FIG. 1 . 
     
    
    
     DEFINITIONS 
     The term “communication” means that material flow is operatively permitted between enumerated components. 
     The term “downstream communication” means that at least a portion of material flowing to the subject in downstream communication may operatively flow from the object with which it communicates. 
     The term “upstream communication” means that at least a portion of the material flowing from the subject in upstream communication may operatively flow to the object with which it communicates. 
     The term “direct communication” means that flow from the upstream component enters the downstream component without undergoing a compositional change due to physical fractionation or chemical conversion. 
     The term “bypass” means that the object is out of downstream communication with a bypassing subject at least to the extent of bypassing. 
     The term “column” means a distillation column or columns for separating one or more components of different volatilities. Unless otherwise indicated, each column includes a condenser on an overhead of the column to condense and reflux a portion of an overhead stream back to the top of the column and a reboiler at a bottom of the column to vaporize and send a portion of a bottoms stream back to the bottom of the column. Feeds to the columns may be preheated. The top pressure is the pressure of the overhead vapor at the vapor outlet of the column. The bottoms temperature is the liquid bottoms outlet temperature. Overhead lines and bottoms lines refer to the net lines from the column downstream of any reflux or reboil to the column. Stripping columns omit a reboiler at a bottom of the column and instead provide heating requirements and separation impetus from a fluidized inert media such as steam. 
     As used herein, the term “True Boiling Point” (TBP) means a test method for determining the boiling point of a material which corresponds to ASTM D-2892 for the production of a liquefied gas, distillate fractions, and residuum of standardized quality on which analytical data can be obtained, and the determination of yields of the above fractions by both mass and volume from which a graph of temperature versus mass % distilled is produced using fifteen theoretical plates in a column with a 5:1 reflux ratio. 
     As used herein, the term “T5” or “T95” means the temperature at which 5 volume percent or 95 volume percent, as the case may be, respectively, of the sample boils using ASTM D-86. 
     As used herein, the term “initial boiling point” (IBP) means the temperature at which the sample begins to boil using ASTM D-86. 
     As used herein, the term “end point” (EP) means the temperature at which the sample has all boiled off using ASTM D-86. 
     As used herein, the term “diesel cut point” is between about 343° C. (650° F.) and about 399° C. (750° F.) using the TBP distillation method. 
     As used herein, the term “diesel boiling range” means hydrocarbons boiling in the range of between about 132° C. (270° F.) and the diesel cut point using the TBP distillation method. 
     As used herein, the term “diesel conversion” means conversion of feed that boils above the diesel cut point to material that boils at or below the diesel cut point in the diesel boiling range. 
     As used herein, the term “separator” means a vessel which has an inlet and at least an overhead vapor outlet and a bottoms liquid outlet and may also have an aqueous stream outlet from a boot. A flash drum is a type of separator which may be in downstream communication with a separator that may be operated at higher pressure. 
     As used herein, the term “predominant” or “predominate” means greater than 50%, suitably greater than 75% and preferably greater than 90%. 
     As used herein, the term “a component-rich stream” means that the rich stream coming out of a vessel has a greater concentration of the component than the feed to the vessel. 
     DETAILED DESCRIPTION 
     An FCC unit and a hydrocracking unit are integrated to increase the value of the final products by recovering additional feed to the hydrocracking unit from the FCC clarified slurry oil (CSO) product. Cycle oil material in the CSO is separated and used as additional feed to the hydrocracking unit. A vacuum flash drum or vacuum column is used to recover lighter material from the CSO. The recovered overhead product is then sent to the hydrocracking unit in order to make more diesel and/or petrochemical products. The additional feed is converted in the hydrocracking unit to additional lighter products such as gasoline, kerosene, diesel, ethylene, propylene and aromatics. 
       FIG. 1 , wherein like numerals designate like components, illustrates an apparatus and process  8  that is equipped for processing a fresh hydrocarbon feed stream. The apparatus and process  8  generally include an FCC unit  10 , an FCC recovery section  50 , a hydrocracking unit  100 , and a hydrocracking recovery section  120 . 
     The fresh hydrocarbon feed may be introduced in an FCC feed line  15 . A conventional FCC feedstock and higher boiling hydrocarbon feedstock are suitable fresh hydrocarbon feed streams. The most common of such conventional fresh hydrocarbon feedstocks is a “vacuum gas oil” (VGO), which is typically a hydrocarbon material having a boiling range with an IBP of around or about 340° C. (644° F.), a T5 between about 340° C. (644° F.) to about 350° C. (662° F.), a T95 between about 555° C. (1031° F.) and about 570° C. (1058° F.) and an EP of around or about 570° C. (1058° F.) prepared by vacuum fractionation of atmospheric residue. Such a fraction is generally low in coke precursors and heavy metal contamination which can serve to contaminate catalyst. Atmospheric residue is a preferred feedstock boiling with an IBP of around or about 340° C. (644° F.), a T5 between about 340° C. (644° F.) and about 360° C. (680° F.) and a T95 of between about 700° C. (1292° F.) and about 900° C. (1652° F.) obtained from the bottom of an atmospheric crude distillation column. Atmospheric residue is generally high in coke precursors and metal contamination. Other heavy hydrocarbon feedstocks which may serve as fresh hydrocarbon feed include heavy bottoms from crude oil, heavy bitumen crude oil, shale oil, tar sand extract, deasphalted residue, products from coal liquefaction, vacuum reduced crudes. Fresh hydrocarbon feedstocks also include mixtures of the above hydrocarbons and the foregoing list is not comprehensive. 
       FIG. 1  shows a typical FCC unit  10  which includes an FCC reactor  12  comprising a riser  20  and a catalyst regenerator  14 . The FCC feed stream in the FCC feed line  15  is fed to the riser  20  via distributors  16  to be contacted with a regenerated cracking catalyst. Regenerated cracking catalyst entering from a regenerated catalyst standpipe  18  is contacted with the FCC feed stream in the riser  20  of the FCC reactor  12 . In the riser  20  of the FCC reactor  12 , the FCC feed stream is contacted with catalyst to catalytically crack the FCC feed stream to provide a cracked stream. 
     The contacting of the FCC feed stream with cracking catalyst may occur in the riser  20  of the FCC reactor  12 , extending upwardly to the bottom of a reactor vessel  22 . The contacting of feed and catalyst is fluidized by gas from a fluidizing line  24 . Heat from the catalyst vaporizes the FCC feed stream, and the FCC feed stream is thereafter cracked to lighter molecular weight hydrocarbons in the presence of the cracking catalyst as both are transferred up the riser  20  into the reactor vessel  22 . The cracked stream of hydrocarbon products in the riser  20  is thereafter disengaged from the cracking catalyst using cyclonic separators which may include a rough cut separator  26  and one or two stages of cyclones  28  in the reactor vessel  22 . A cracked stream of product gases exit the reactor vessel  22  through a product outlet  31  to line  32  for transport to a downstream FCC recovery section  50 . 
     The outlet temperature of the cracked products leaving the riser  20  should be between about 472° C. (850° F.) and about 593° C. (1100° F.). Inevitable side reactions occur in the riser  20  leaving coke deposits on the catalyst that lower catalyst activity. The spent or coked catalyst requires regeneration for further use. Coked catalyst, after separation from the gaseous cracked product hydrocarbons, falls into a stripping section  34  where steam is injected through a nozzle  35  and distributor to purge any residual hydrocarbon vapor. After the stripping operation, the coked catalyst is fed to the catalyst regenerator  14  through a spent catalyst standpipe  36 . 
       FIG. 1  depicts a regenerator  14  known as a combustor. However, other types of regenerators are suitable. In the catalyst regenerator  14 , a stream of oxygen-containing gas, such as air, is introduced through an air distributor  38  to contact the coked catalyst, burn coke deposited thereon, and provide regenerated catalyst and flue gas. A stream of air or other oxygen containing gas is fed into the regenerator  14  through line  37 . Catalyst and air flow upwardly together along a combustor riser  40  located within the catalyst regenerator  14  and, after regeneration, are initially separated by discharge through a disengager  42 . Finer separation of the regenerated catalyst and flue gas exiting the disengager  42  is achieved using first and second stage separator cyclones  44 ,  46 , respectively, within the catalyst regenerator  14 . Catalyst separated from flue gas dispenses through diplegs from cyclones  44 ,  46  while flue gas significantly lighter in catalyst sequentially exits cyclones  44 ,  46  and exit the regenerator vessel  14  through flue gas outlet  47  in line  48 . Regenerated catalyst is recycled back to the reactor riser  20  through the regenerated catalyst standpipe  18 . 
     As a result of the coke burning, the flue gas vapors exiting at the top of the catalyst regenerator  14  in line  48  contain CO, CO 2  and H 2 O, along with smaller amounts of other species. Catalyst regeneration temperature is between about 500° C. (932° F.) and about 900° C. (1652° F.). Both the cracking and regeneration occur at an absolute pressure between about 0.5 and about 5 atmospheres. 
     In the FCC recovery section  50 , the gaseous cracked stream in line  32  is fed to a lower section of an FCC main fractionation column  52 . The main fractionation column  52  is in downstream communication with the riser  20  and the FCC reactor  12 . Several fractions may be fractionated and taken from the main fractionation column  52  including a CSO stream from the bottom in main bottoms line  58 , an optional heavy cycle oil (HCO) stream in line  54 , an LCO in line  55  and an optional heavy naphtha stream in line  56 . In  FIG. 1 , a heavy cycle oil (HCO) stream in line  54  may only be pumped around to cool the main fractionation column  52  without an HCO product stream being taken. Gasoline and gaseous light hydrocarbons are removed in a main overhead line  57  from the main fractionation column  52  and condensed before entering a main column receiver  59 . An aqueous stream is removed from a boot in the receiver  59 . Moreover, a condensed unstabilized, light naphtha stream is removed in a main column receiver bottoms line  61  while a gaseous light hydrocarbon stream is removed in overhead line  62 . A portion of the light naphtha stream in bottoms line  61  may be refluxed to the main fractionation column  52  while a light unstabilized naphtha stream is withdrawn in line  63 . Both streams in lines  62  and  63  may enter a vapor recovery section downstream of the main fractionation column  52 . 
     The light unstabilized naphtha fraction preferably has an initial boiling point (IBP) in the C 5  range; i.e., between about 24° C. (75° F.) and about 35° C. (95° F.), and an end point (EP) at a temperature greater than or equal to about 149° C. (300° F.). The optional heavy naphtha fraction has an IBP just above about 149° C. (300° F.) and an EP at a temperature above about 204° C. (400° F.), preferably between about 200° C. (392° F.) and about 221° C. (430° F.). The LCO stream has an IBP of at least 149° C. (300° F.) if no heavy naphtha cut is taken or at about the EP temperature of the heavy naphtha if a heavy naphtha cut is taken and an EP in a range of about 360° C. (680° F.) to about 382° C. (720° F.). The LCO stream may have a T5 in the range of about 213° C. (416° F.) to about 244° C. (471° F.) and a T95 in the range of about 354° C. (669° F.) to about 377° C. (710° F.). The optional HCO stream has an IBP just above the EP temperature of the LCO stream and an EP in a range of about 385° C. (725° F.) to about 482° C. (900° F.) and preferably about 427° C. (800° F.). The HCO stream may have a T5 in the range of about 332° C. (630° F.) to about 349° C. (660° F.) and a T95 in the range of about 382° C. (720° F.) to about 460° C. (860° F.) and preferably about 404° C. (760° F.). The CSO stream has an IBP just above the EP temperature of the HCO stream or the LCO stream if the HCO stream is not taken and includes everything boiling at a higher temperature. Any or all of lines  54 - 56  may be cooled and pumped back to the main column  52  to cool the main column typically at a higher location. 
     A vacuum separator  70  may be in downstream communication with the main bottoms line  58  of the main fractionation column  52 . In an aspect, a heater  68  such as a fired heater is on the main bottoms line  58  in downstream communication with the main bottoms line  58  and the main fractionation column  52 . The heater  68  can be used to heat the CSO stream to further prepare it for separation in the vacuum separator  70 . The fired heater may heat the CSO stream to between about 371° C. (700° F.) to about 410° C. (770° F.). The vacuum separator is in downstream communication with the heater  68 . A feed inlet  58   i  to the vacuum separator  70  for the main bottoms line  58  admits CSO to the separator  70 . 
     The vacuum separator  70  may be a fractionation column with or without a reboiler or it may be a simple one-stage flash separator. The vacuum separator  70  separates the slurry oil stream into a cycle oil stream and a heavy stream under vacuum pressure of about 5 and about 25 kPa (absolute) and a temperature between about 332° C. (630° F.) to about 354° C. (670° F.). The cycle oil stream may comprise at least some material boiling in the LCO range and/or at least some material boiling in the HCO range. 
     In an aspect, the cycle oil stream is comprised in a vaporous separator overhead stream transported in a separator overhead line  72  from a top of the vacuum separator  70  while the heavy stream is in a separator bottoms stream transported in a separator bottoms line  74  from a bottom of the vacuum separator  70 . An optional recycle line  75  may be in downstream communication with the separator bottoms line  74  and the separator  70  may be in downstream communication with the recycle line. The recycle line  75  recycles a portion of the heavy stream from the separator bottoms line  74  from a bottom of the separator  70  back to the separator  70 . The recycle line  75  recycles to a recycle inlet  75   i  that is above a feed inlet  58   i  of the CSO stream to the separator  70 . The net heavy stream comprising concentrated CSO is removed in line  77  and can be sold as fuel oil or as feed to a coker unit or for carbon black production. 
     A cooler  76  may be in downstream communication with the separator overhead line  72  for cooling and condensing the separator overhead stream. The condensed separator overhead stream enters a receiver  80  in downstream communication with the separator overhead line  72  from a top of the separator  70 . The condensed overhead stream is separated in the receiver  80  into the liquid cycle oil stream taken from a bottom of the receiver  80  in a receiver bottoms line  82  and a vaporous receiver overhead stream taken in receiver overhead line  78 . The liquid cycle oil stream in the receiver bottoms line  82  is LCO and HCO rich and provides a cycle oil process stream which can be taken to an LCO pool, a diesel pool or to the hydrocracking unit  100  in hydroprocessing feed line  84 . The receiver  80  may be operated under vacuum pressure of about 2 and about 10 kPa (absolute) and a temperature between about 37° C. (100° F.) to about 149° C. (300° F.), preferably no more than about 121° C. (250° F.). 
     The cycle oil stream recovered in the hydroprocessing feed line  84  may comprise about 5 to about 50 vol % and suitably about 20 to about 30 vol % of the CSO stream in main column bottoms line  58 . Additionally, the API of the cycle oil stream in line  84  may decrease 1-5 and suitably 2-4 API numbers relative to the CSO stream in main column bottoms line  58 . 
     In an embodiment, if the vacuum separator  70  is a vacuum fractionation column, the liquid cycle oil stream in receiver bottoms line may be split between the cycle oil process stream in a hydroprocessing feed line  84  and a reflux stream in a reflux line  86  for reflux of a portion of the liquid cycle oil stream in the receiver bottoms line  82  from a bottom of the receiver  80  to the vacuum separator  70  through the reflux inlet  86   i . The reflux line  86  may be in downstream communication with the receiver bottoms line  82  and the vacuum separator  70 , and the vacuum separator may be in downstream communication with the reflux line  86 . The reflux inlet  86   i  to the vacuum separator  70  is for the reflux line  86  which is at a higher elevation than the feed inlet  58   i  to the separator  70  for the main bottoms line  58  and a recycle inlet  75   i  to the separator  70  for the recycle line  75 . In this embodiment, a packing  71  may be disposed in the vacuum column between the recycle inlet  75   i  and the reflux inlet  86   i . Refluxing the liquid cycle oil stream to the vacuum fractionation column enables control of the end point of the cycle oil process stream to satisfy feed requirements to downstream units, such as the hydrocracking unit  100 . 
     The vacuum separator  70  is operated at below atmospheric pressure in the separator overhead line  72 . A vacuum generating device  88  such as an eductor or a vacuum pump is in downstream communication with the receiver overhead line  78  of the receiver  80  for pulling a vacuum on the receiver overhead stream from the receiver  80 . In an embodiment, when the vacuum generating device  88  is an eductor, the eductor may be in downstream communication with an inert gas stream  89  such as steam which pulls a vacuum on the receiver overhead stream in the receiver overhead line  78 . The eductor feeds the inert gas stream mixed with the receiver overhead stream to a condenser. The condensed mixture of the inert gas stream and the receiver overhead stream exit the condenser and enter into a drain drum  90 . A vaporous hydrocarbon stream in line  92  from the drain drum  90  may be vented to flare or recovery. A condensed stream of sour water may also be removed from the drain drum in drum bottoms line  94  and taken to water treatment facilities for the FCC unit  10  which is not described. 
     Because LCO may be recovered from the CSO stream in the main bottoms line  58 , additional LCO may be allowed to flow into the CSO stream by reducing the LCO draw in line  55 . This allows the main fractionation column  52  to operate at lower bottoms temperature to prevent coking in the main fractionation column. LCO is then recovered in the cycle oil process stream in hydroprocessing feed line  84  avoiding LCO loss and giving more flexibility to the operation of the main fractionation column  52 . 
     The cycle oil process stream may be transported in the hydroprocessing feed line  84  to the hydrocracking unit  100  to hydrocrack at least a portion of the cycle oil process stream over hydrocracking catalyst to provide a diesel product stream and/or petrochemical feedstock. The hydrocracking unit  100  may be in downstream communication with the receiver bottoms line  82 . The cycle oil process stream may be mixed with another hydrocarbon feed stream in line  102  to provide a blended hydrocracking feed stream in line  104 . The other hydrocarbon feed stream in line  102  may be an LCO stream or it may comprise material having an initial boiling point suitably no less than about 150° C. (302° F.) and preferably no less than about 288° C. (550° F.), such as atmospheric gas oils, VGO, deasphalted, vacuum, and atmospheric residua, coker distillates, straight run distillates, solvent-deasphalted oils, pyrolysis-derived oils, high boiling synthetic oils, HCO, hydrocracked feeds, cat cracker distillates and the like. Suitable feeds may provide an end point after being blended with the cycle oil process stream in hydroprocessing feed line  84  to provide the blended hydrocracking feed stream with an end point of no more than about 482° C. (900° F.), suitably no more than about 468° C. (875° F.) and preferably no more than about 454° C. (850° F.). The T95 of the blended stream may be no more than about 438° C. (820° F.), preferably about 448° C. (840° F.), to about 471° C. (880° F.), preferably about 460° C. (860° F.). The blended hydrocracking feed stream may contain from about 0.1 to about 4 wt % sulfur and 300 to 1800 wppm nitrogen. The blended hydrocracking feed stream may be heated, mixed with a hydrogen stream in line  106  and fed to the hydroprocessing vessel  110 . 
     In an aspect of the present invention, the hydroprocessing vessel  110  may include a hydrotreating reactor  112  to remove nitrogen and sulfur species and to saturate aromatic rings in the hydrocarbon feed stream. In the hydrotreating reactor, between about 60 to about 90 wt % and preferably about 70 to about 80 wt % of the multi-ring aromatics may be saturated to have just one aromatic ring. 
     In an aspect, the hydrotreating reactor  112  may be a hydrotreating catalyst bed  112   b  in the hydroprocessing vessel  110 . The hydroprocessing vessel  110  may comprise one or more vessels, multiple beds of catalyst in each vessel, and various combinations of hydrotreating catalyst, hydrocracking catalyst, hydrotreating reactors and hydrocracking reactors in one or more vessels. The preheated, hydrocracking feed stream may be hydrotreated in the presence of the hydrogen stream and hydrotreating catalyst in one or more hydrotreating catalyst beds  112   b  to provide a hydrotreated stream. The hydrotreated stream and unconsumed hydrogen may be transferred to a hydrocracking reactor  114  comprising a hydrocracking catalyst bed  114   b  without any separation or heating. Hydrogen streams may be injected between or after catalyst beds to provide hydrogen requirements and/or to cool catalyst bed effluent. For example, the hydroprocessing vessel  110  in  FIG. 1  is illustrated to have three catalyst beds in one reactor vessel. From zero to two hydrotreating catalyst beds  112   b  of hydrotreating catalyst may be followed by one to three hydrocracking catalyst beds  114   b  in hydroprocessing vessel  110 . Consequently, a hydrotreating reactor  112  may be in downstream communication with the receiver bottoms line  82  and the hydrocracking reactor  114  may be in downstream communication with the hydrotreating reactor  112 . 
     Typical hydrotreating conditions include an average hydrotreating catalyst bed temperature from about 260° C. (500° F.) to about 426° C. (800° F.), often from about 316° C. (600° F.) to about 426° C. (800° F.), and a hydrogen partial pressure from about 4.1 MPa (600 psig) to about 10.5 MPa (1500 psig), often from about 6.2 MPa (800 psig) to about 8.3 MPa (1400 psig). However, if the hydrotreating reactor  112  is in the same hydroprocessing vessel  110  as the hydrocracking reactor  114 , conditions in each will be closer to the same. A typical range of LHSV for the hydrotreating reactor  112  is from about 0.1 to about 10 hr −1 , often from about 0.5 to about 3 hr −1 . 
     Suitable hydrotreating catalysts include those comprising of at least one Group VIII metal, such as iron, cobalt, and nickel, cobalt and/or nickel, and at least one Group VI metal, such as molybdenum and tungsten, on a high surface area support material such as a refractory inorganic oxide such as alumina and optionally with silica amounting to no more than 5 wt % silica. A representative hydrotreating catalyst therefore comprises a metal selected from the group consisting of nickel, cobalt, tungsten, molybdenum, and mixtures thereof, such as a mixture of cobalt and molybdenum, deposited on a refractory inorganic oxide support such as alumina. 
     The hydrotreated effluent stream or the hydrocracking feed stream is hydrocracked in the presence of hydrocracking catalyst and the hydrogen stream in the hydrocracking reactor  114  to provide a hydrocracked effluent stream in hydrocracked effluent line  116 . In some aspects, the hydrocracking reaction provides diesel conversion of at least about 30 vol % and typically no greater than about 60 vol % of the hydrocracking feed. At hydrocracking conditions, the feed is selectively converted to products such as diesel, kerosene, naphtha and gas to provide an upgraded product stream. Pressure may be moderate to allow opening of all but one of the rings. As a result of being hydrocracked, the upgraded hydrocarbon product has a reduced average molecular weight relative to the hydrocracker feed. For example, in the case of a blended hydrocracking feed stream, in an aspect, prior to hydrotreating is predominantly  2 -ring aromatic compounds and multi-ring aromatic compounds, the hydrocracked product may comprise at least about 40% by weight, and often at least about 50% by weight, mono-ring aromatic compounds. In a preferred embodiment, the hydrocracked effluent stream comprises or consists essentially of a mixture of the fuel components naphtha and diesel fuel. In the hydrocracking reactor  114 , between about 60 to about 90 wt % and preferably about 70 to about 80 wt % of the multi-ring compounds may be cracked open to have just one ring intact. Also, due to desulfurization resulting from hydrotreating of all or a portion of the hydrocracking feed stream, the hydrocracked effluent stream may comprise or consist essentially of naphtha and diesel fuel that meet sulfur specifications for ultra low sulfur naphtha and ultra low sulfur diesel. 
     Hydrocracking of the hydrocracking feed stream may be carried out in the presence of a hydrocracking catalyst and hydrogen. Representative hydrocracking conditions include an average hydrocracking catalyst bed temperature from about 260° C. (500° F.) to about 426° C. (800° F.), often from about 316° C. (600° F.) to about 426° C. (800° F.); a hydrogen partial pressure from about 4.1 MPa (600 psig) to about 10.5 MPa (1500 psig), preferably from about 6.2 MPa (800 psig) to about 9.0 MPa (1300 psig); an LHSV from about 0.1 hr −1  to about 30 hr −1 , often from about 0.5 hr −1  to about 3 hr −1 ; and a hydrogen circulation rate from about 2000 standard ft 3  per barrel (337 normal m3/m3) to about 25,000 standard ft 3  per barrel (4200 normal m3/m3), often from about 5000 standard ft 3  per barrel (840 normal m3/m3) to about 15,000 standard ft 3  per barrel (2530 normal m3/m3). 
     The hydrocracking catalysts may utilize amorphous silica-alumina and/or zeolite as cracking bases. A beta zeolite having a silica-to-alumina molar ratio of less than 30:1 and an SF 6  adsorption capacity of at least 28% may be a suitable cracking base. Cracking bases comprising amorphous silica-alumina should have a silica content of 40 wt % or more 
     The zeolite cracking bases are sometimes referred to in the art as molecular sieves and are usually composed of silica, alumina and one or more exchangeable cations such as sodium, magnesium, calcium, rare earth metals, etc. They are further characterized by crystal pores of relatively uniform diameter between about 4 and about 14 angstroms. It is preferred to employ zeolites having a relatively high silica-to-alumina molar ratio between about 3 and about 12. Suitable zeolites found in nature include, for example, mordenite, stilbite, heulandite, ferrierite, dachiardite, chabazite, erionite and faujasite. Suitable synthetic zeolites include, for example, the B, X, Y and L crystal types, e.g., synthetic faujasite and mordenite. The preferred zeolites are those having crystal pore diameters between about 8 to 12 angstroms, wherein the silica-to-alumina molar ratio is about 4 to 6. One example of a zeolite falling in the preferred group is synthetic Y molecular sieve. 
     The naturally occurring zeolites are normally found in a sodium form, an alkaline earth metal form, or mixed forms. The synthetic zeolites are nearly always prepared first in the sodium form. In any case, for use as a cracking base it is preferred that most or all of the original zeolitic monovalent metals be ion-exchanged with a polyvalent metal and/or with an ammonium salt followed by heating to decompose the ammonium ions associated with the zeolite, leaving in their place hydrogen ions and/or exchange sites which have actually been decationized by further removal of water. Hydrogen or “decationized” Y zeolites of this nature are more particularly described in U.S. Pat. No. 3,130,006. 
     Mixed polyvalent metal-hydrogen zeolites may be prepared by ion-exchanging first with an ammonium salt, then partially back exchanging with a polyvalent metal salt and then calcining. In some cases, as in the case of synthetic mordenite, the hydrogen forms can be prepared by direct acid treatment of the alkali metal zeolites. In one aspect, the preferred cracking bases are those which are at least about 10 wt %, and preferably at least about 20 wt %, metal-cation-deficient, based on the initial ion-exchange capacity. In another aspect, a desirable and stable class of zeolites is one wherein at least about 20 wt % of the ion exchange capacity is satisfied by hydrogen ions. 
     The hydrogenation metals deposited on the base of the hydrocracking catalysts are those of Group VIII, i.e., iron, cobalt, nickel, ruthenium, rhodium, palladium, osmium, iridium and platinum. In addition to these metals, other promoters may also be employed in conjunction therewith, including the metals of Group VIB, e.g., molybdenum and tungsten. The amount of hydrogenation metal in the catalyst can vary within wide ranges. Broadly speaking, any amount between about 0.05 percent and about 30 percent by weight may be used. In the case of the noble metals, it is normally preferred to use about 0.05 to about 2 wt %. 
     The foregoing catalysts may be employed in undiluted form, or the powdered catalyst may be mixed and copelleted with other relatively less active catalysts, diluents or binders such as alumina, silica gel, silica-alumina cogels, activated clays and the like in proportions ranging between about 5 and about 90 wt %. These diluents may be employed as such or they may contain a minor proportion of an added hydrogenating metal such as a Group VIB and/or Group VIII metal. Additional metal promoted hydrocracking catalysts may also be utilized in the process of the present invention which comprises, for example, aluminophosphate molecular sieves, MFI zeolites, crystalline chromosilicates and other crystalline silicates. 
     A hydrocracked effluent exits the hydrocracking reactor  114  in the hydrocracked effluent line  116 . A hydrocracking recovery section  120  may be provided in downstream communication with the hydrocracked effluent line  116 . The hydrocracked effluent stream may be cooled and separated in a hot separator  122 . The hot separator  122  separates the hydrocracked effluent to provide a vaporous hydrocarbonaceous hot separator overhead stream in an overhead line  124  and a liquid hydrocarbonaceous hot separator bottoms stream in a bottoms line  126 . The hot separator  122  is in direct downstream communication with the hydrocracking reactor  114  The hot separator  122  operates at about 177° C. (350° F.) to about 371° C. (700° F.). The hot separator  122  may be operated at a slightly lower pressure than the hydrocracking reactor  114  accounting for pressure drop of intervening equipment. 
     The vaporous hydrocarbonaceous hot separator overhead stream in the overhead line  124  may be cooled before entering a cold separator  130 . To prevent deposition of ammonium bisulfide or ammonium chloride salts in the line  124  transporting the hot separator overhead stream, a suitable amount of wash water (not shown) may be introduced into line  124 . 
     The cold separator  130  serves to separate hydrogen from hydrocarbon in the hydrocracking effluent for recycle to the hydroprocessing reactor vessel  110 . The vaporous hydrocarbonaceous hot separator overhead stream may be separated in the cold separator  130  to provide a vaporous cold separator overhead stream comprising a hydrogen-rich gas stream in an overhead line  132  and a liquid cold separator bottoms stream in the bottoms line  134 . The cold separator  130 , therefore, is in downstream communication with the overhead line  124  of the hot separator  122 . The cold separator  130  may be operated at about 100° F. (38° C.) to about 150° F. (66° C.) and just below the pressure of the hydrocracking reactor  114  and the hot separator  122  accounting for pressure drop of intervening equipment to keep hydrogen and light gases in the overhead and normally liquid hydrocarbons in the bottoms. The cold separator  130  may also have a boot for collecting an aqueous phase in line  136 . 
     The liquid hydrocarbonaceous stream in the hot separator bottoms line  134  may be let down in pressure and flashed in a hot flash drum  140  to provide a hot flash overhead stream of light ends in an overhead line  142  and a heavy liquid stream in a hot flash bottoms line  144 . The hot flash drum  126  may be operated at the same temperature as the hot separator  122  but at a lower pressure. The heavy liquid stream in bottoms line  144  may be stripped of gases in a stripping column  160 . 
     In an aspect, the liquid hydroprocessing effluent stream in the cold separator bottoms line  134  may be let down in pressure and flashed in a cold flash drum  150 . The cold flash drum may be in downstream communication with a bottoms line  134  of the cold separator  128 . In a further aspect, the vaporous hot flash overhead stream in overhead line  142  may be cooled and also separated in the cold flash drum  150 . The cold flash drum  150  may separate the cold separator liquid bottoms stream in line  134  and the hot flash vaporous overhead stream in overhead line  142  to provide a cold flash overhead stream of light ends in overhead line  152  and a cold flash bottoms stream in a bottoms line  154 . The cold flash bottoms stream in bottoms line  154  may be introduced to the stripping column  160 . In an aspect, the stripping column  160  may be in downstream communication with the cold flash bottoms line  154  and the hot flash bottoms line  144 . 
     The cold flash drum  150  may be in downstream communication with the bottoms line  134  of the cold separator  130 , the overhead line  142  of the hot flash drum  140  and the hydrocracking reactor  114 . In an aspect, the hot flash overhead line  142  joins the cold separator bottoms line  134  which feeds the hot flash overhead stream and the cold separator bottoms stream together to the cold flash drum  150 . The cold flash drum  150  may be operated at the same temperature as the cold separator  130  but typically at a lower pressure. The aqueous stream in line  136  from the boot of the cold separator  130  may also be directed to the cold flash drum  150 . A flashed aqueous stream is removed from a boot in the cold flash drum  150 . 
     The vaporous cold separator overhead stream comprising hydrogen in the overhead line  132  is rich in hydrogen. The cold separator overhead stream in overhead line  132  may be passed through a scrubbing tower  170  to remove hydrogen sulfide and ammonia by use of an absorbent such as an amine absorbent. The scrubbed hydrogen-rich stream may be compressed in a recycle compressor  172  to provide a recycle hydrogen stream and supplemented with a make-up hydrogen stream from line  174  to provide the hydrogen stream in hydrogen line  106 . 
     The hot flash bottom stream in hot flash bottoms line  144  and the cold flash bottoms stream in the cold flash bottoms line  154  may be fed to the stripper column  160  to be stripped of light gases such as hydrogen sulfide. The cold flash bottoms stream may enter the stripping column  160  at a higher elevation than the hot flash bottoms stream  154 . The hydrocracking effluent in the hot flash bottoms stream and the cold flash bottoms stream may be stripped in the stripping column  160  with a stripping media which is an inert gas such as steam from line  162  to provide an off-gas stream of hydrogen, hydrogen sulfide, steam and other light gases in an overhead line  164  for further treating. The stripper column  160  may be operated with a bottoms temperature between about 160° C. (320° F.) and about 360° C. (680° F.) and an overhead pressure of about 0.5 MPa (gauge) (73 psig) to about 2.0 MPa (gauge) (292 psig). 
     A stripped hydrocracked stream is produced in a stripper bottoms line  166 . At least a portion of the stripped hydrocracked stream in bottoms line  166  may be fed to a product fractionation column  180 . Consequently, the product fractionation column  180  is in downstream communication with the stripper bottoms line  166  of the stripper column  160 . 
     The product fractionation column  180  may be in downstream communication with the hydrocracking reactor  114  for separating portions of the hydrocracking effluent stream into product streams. The hydroprocessing fractionation column  180  fractionates the stripped hydrocracking effluent by use of an inert stripping media such as steam from line  182 . The product streams produced by the hydroprocessing fractionation column  180  may include an overhead LPG stream in overhead line  184 , a naphtha stream in line  186 , a kerosene stream carried in line  188  from a side outlet and a diesel stream in a bottoms line  190 . If heavier feeds are fed to the hydroprocessing reactor  110 , the diesel stream may be withdrawn from an additional, optional side outlet in line  189  and an unconverted oil stream may be withdrawn in the bottoms line  190  which may be recycled to the FCC unit  10  or recycled to the hydroprocessing reactor  110 . The fractionation overhead stream may be condensed and separated in a receiver with a portion of the condensed liquid being refluxed back to the hydroprocessing fractionation column  180 . The net naphtha stream in line  186  may require further processing such as in a naphtha splitter column before blending in the gasoline pool or it may be fed to a steam cracker for petrochemical production. The product fractionation column  180  may be operated with a bottoms temperature between about 288° C. (550° F.) and about 370° C. (700° F.) and at an overhead pressure between about 30 kPa (gauge) (4 psig) to about 200 kPa (gauge) (29 psig). 
     If aromatics recovery is desired over fuel production, portions of the naphtha stream in line  186  and the diesel stream in line  189  or  190  from the product fractionation column  180  may routed to a transalkylation unit for the production of xylenes. 
       FIG. 2  illustrates an embodiment in which recovered light material is recycled to the main column  52 ′. Many of the elements in  FIG. 2  have the same configuration as in  FIG. 1  and bear the same reference number. Elements in  FIG. 2  that correspond to elements in  FIG. 1  but have a different configuration bear the same reference numeral as in  FIG. 1  but are marked with a prime symbol (′). 
     In  FIG. 2 , a main fractionation column  52 ′ is in downstream communication with the FCC reactor  10 . A vacuum separator  70 ′ may be in downstream communication with a main bottoms line  58  of the main fractionation column  52 ′. In an aspect, a heater  68  such as a fired heater may be on the main bottoms line  58  in downstream communication with the main bottoms line  58  and the main fractionation column  52 ′. The heater  68  can be used to heat the CSO stream to further prepare it for separation in the vacuum separator  70 . The fired heater may heat the CSO stream to between about 371° C. (700° F.) to about 410° C. (770° F.). The vacuum separator  70 ′ is in downstream communication with the heater  68 . A feed inlet  58   i  to said vacuum separator  70 ′ for the main bottoms line  58  admits CSO to the separator  70 . 
     The vacuum separator  70  may be a fractionation column or it may be a simple one-stage flash separator. The vacuum separator  70 ′ separates the slurry oil stream into a cycle oil stream and a heavy stream under vacuum pressure of about 5 and about 25 kPa (absolute) and a temperature between about 332° C. (630° F.) to about 354° C. (670° F.). 
     The heavy stream is transported from the separator  70 ′ in a separator bottoms line  74 ′ and can be sold as fuel oil or as feed to a coker unit or to make carbon black. The cycle oil stream is comprised in an overhead stream of the vacuum separator  70 ′ in a separator overhead line  72 . A cooler  76  is in downstream communication with the separator overhead line  72 . The overhead stream is condensed in the cooler  76  and separated in a receiver  80 ′. 
     The condensed separator overhead stream enters the receiver  80 ′ which is in downstream communication with the separator overhead line  72  of the vacuum separator  70 ′. The condensed overhead stream is separated in the receiver  80 ′ into the liquid cycle oil stream taken from a bottom of the receiver  80 ′ in a receiver bottoms line  82 ′. A vaporous receiver overhead stream is taken in receiver overhead line  78 . The liquid cycle oil stream in the receiver bottoms line  82 ′ is LCO and HCO rich and provides a cycle oil process stream. The receiver  80 ′ may be operated under vacuum pressure of about 2 and about 10 kPa (absolute) and a temperature between about 37° C. (100° F.) to about 149° C. (300° F.), preferably no more than about 121° C. (250° F.). 
     The vacuum separator  70 ′ is operated at below atmospheric pressure in the separator overhead line  72 . A vacuum generating device  88  such as an eductor may be in downstream communication with the receiver overhead line  78  of the receiver  80  for pulling a vacuum on the receiver overhead stream from the receiver  80  as explained with respect to  FIG. 1 . 
     The embodiment of  FIG. 2  has the main fractionation column  52 ′ in downstream communication with the vacuum separator  80 ′ and specifically with the receiver bottoms line  82 ′ of the receiver  80 ′. The receiver bottoms line  82 ′ refluxes the cycle oil stream to the main fractionation column  52 ′. A reflux inlet  82   i  to the main fractionation column  52 ′ for the receiver bottoms line  82 ′ may be in downstream communication with the vacuum separator  70 ′. Additionally, the main fractionation column  52 ′ also may be in downstream communication with the separator overhead line  72  of the vacuum separator  70 ′. The cycle oil process stream is re-fractionated in the main fractionation column to remove a heavy tail of higher boiling materials from the cycle oil process stream. The reflux inlet  82   i  may be located at an elevation above the bottom of the main fractionation column  52 ′ but at a lower elevation than a side outlet  54   o  of the main fractionation column. The side outlet  54   o  may be for withdrawing a cycle oil stream from a side  53  of the main fractionation column  52 ′ from the side outlet  54   o  that is at a higher elevation than an inlet  82   i  of the cycle oil process stream refluxed to the main fractionation column. The side outlet  54   o  is preferably a liquid draw of a liquid cycle oil stream from the main fractionation column  52 ′. 
     The cycle oil stream may be withdrawn from the side  53  of the main fractionation column  52 ′ in a cycle oil line  54 ′ and split into a portion in a return stream in a return line  57  and another portion in a hydroprocessing feed stream in a hydroprocessing feed line  84 ′. A return line  57  to said main fractionation column may be in downstream communication with the side outlet  54   o . A hydrocracking unit  100  is in downstream communication with the side outlet  54   o  of the main fractionation column  52 ′. The portion of the cycle oil stream from the main fractionation column  52 ′ in the hydroprocessing feed line  84 ′ may be hydrocracked in the hydrocracking unit  100 , and the other portion of the cycle oil stream in the return line may be returned to the main fractionation column  52 ′. A cooler  65  on the return line  57  cools the other portion of the cycle oil stream comprising the return stream before it is returned to the main fractionation column  52 ′ after the hydroprocessing feed stream in line  84 ′ is taken from the cycle oil stream in cycle oil line  54 ′. 
     The hydroprocessing feed stream comprising a cycle oil stream from the main fractionation column in hydroprocessing feed line  84 ′ may be hydrocracked in the hydrocracking unit  100  as described with respect to  FIG. 1 . A hydrotreating reactor  112  may be in communication with the side outlet  54   o  of the main fractionation column  52 ′ and a hydrocracking reactor  114  may be in downstream communication with said hydrotreating reactor  112 . As explained with respect to  FIG. 1 , a diesel stream and/or an aromatics stream may be recovered from the hydrocracked cycle oil stream. All aspects of the embodiments of  FIG. 1  are applicable to  FIG. 2  unless stated otherwise. 
     EXAMPLES 
     Example 1 
     The described embodiment was simulated to demonstrate its usefulness. The first base case refinery sends hydrotreated atmospheric resid feed to an FCC unit at a rate of 603 m 3 /h with 166 m 3 /h of LCO and diesel that is fed to a hydrocracking unit. The base case refinery is equipped to upgrade and produce aromatics or feedstock for a steam cracker for making ethylene and propylene. By using a vacuum column or vacuum flash drum to recover light material from FCC, CSO product, approximately 25 vol % of cycle oil material can be recovered relative to the CSO product. The cycle oil material is then sent to the hydrocracking unit, to increase hydrocracking unit feed rate by 3.0 vol % to 171 m 3 /h. Due to the increased feed rate to the hydrocracking unit, total product yield from the steam cracker for light olefins and the hydrocracking unit for aromatics will increase as shown in Table 1. 
     
       
         
           
               
               
               
             
               
                   
                 TABLE 1 
               
               
                   
                   
               
               
                   
                 Stream 
                 Increase, wt % 
               
               
                   
                   
               
             
            
               
                   
                 Hydrocracking feed 
                 3.4 
               
               
                   
                 Ethylene 
                 3.8 
               
               
                   
                 Propylene 
                 3.9 
               
               
                   
                 Benzene 
                 4.1 
               
               
                   
                 Toluene 
                 4.1 
               
               
                   
                 Xylenes 
                 4.1 
               
               
                   
                   
               
            
           
         
       
     
     Example 2 
     In a second base case, the refinery is equipped for fuels production. The second base case refinery sends hydrotreated atmospheric resid feed to an FCC unit at a rate of 576 m 3 /h with 364 m3/h of LCO and diesel that is fed to a hydrocracking unit. By using a vacuum column or vacuum flash drum to recover light material from FCC, CSO product, approximately 25 vol % of cycle oil material can be recovered relative to the CSO product. The light material is then sent to the hydrocracking unit, to increase hydrocracking unit feed rate by 1.3 vol % to 369 m 3 /h. Due to the increased feed rate to the hydrocracking unit, total product yield from the hydrocracking unit will increase as shown in Table 2. 
     
       
         
           
               
               
               
             
               
                   
                 TABLE 2 
               
               
                   
                   
               
               
                   
                 Stream 
                 Increase, wt % 
               
               
                   
                   
               
             
            
               
                   
                 Hydrocracking feed 
                 1.5 
               
               
                   
                 95 RON Euro V Gasoline 
                 2.5 
               
               
                   
                 Kerosene/Jet Fuel 
                 1.3 
               
               
                   
                 Euro V Diesel 
                 0.9 
               
               
                   
                 LPG 
                 4.1 
               
               
                   
                   
               
            
           
         
       
     
     Example 3 
     Various embodiments of the present invention were simulated to assess the additional feed produced for the hydrocracking unit. 
     In a first simulation, 38,208 kg/hr of CSO at 363° C. (685° F.) is fed to a vacuum flash drum. 
     In a second simulation, the same feed is sent to a vacuum fractionation column without a reboiler. A reflux stream of 1,956 kg/hr of a liquid cycle oil stream taken from a bottom of the overhead receiver in a receiver bottoms line is refluxed to the vacuum fractionation column. 
     In a third simulation, the same feed is heated to 382° C. (720° F.) in a fired heater before being fed to a vacuum fractionation column and a reflux stream of only 1059 kg/hr a liquid cycle oil stream taken from a bottom of the overhead receiver in a receiver bottoms line is refluxed to the vacuum fractionation column. 
     In a fourth simulation, 38,301 kg/hr of CSO at 363° C. (685° F.) is fed to a vacuum flash drum, but 5,777 kghr of the cycle oil process stream from the overhead receiver bottoms is refluxed to the main fractionation column. The hydrocracking feed is taken as a portion of the HCO stream withdrawn from a side of the main fractionation column. 
     A comparison of the additional cycle oil, hydrocracking feeds are shown in Table 3. Boiling point properties are provided using TBP. 
     
       
         
           
               
               
               
               
               
               
             
               
                   
                 TABLE 3 
               
               
                   
                   
               
               
                   
                   
                 Flow rate, 
                 Fraction of 
                 T95, 
                 End Point, 
               
               
                   
                 Simulation 
                 kg/hr 
                 CSO, wt % 
                 ° C. 
                 ° C. 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
            
               
                   
                 1 
                 7584 
                 20 
                 490 
                 557 
               
               
                   
                 2 
                 2083 
                 5 
                 416 
                 448 
               
               
                   
                 3 
                 8614 
                 23 
                 471 
                 510 
               
               
                   
                 4 
                 5777 
                 15 
                 419 
                 456 
               
               
                   
                   
               
            
           
         
       
     
     These embodiments produce suitable hydrocracking feedstock in substantial quantities that may be hydrocracked alone or blended with other hydrocracking feed for hydrocracking to upgraded products. 
     SPECIFIC EMBODIMENTS 
     While the following is described in conjunction with specific embodiments, it will be understood that this description is intended to illustrate and not limit the scope of the preceding description and the appended claims. 
     A first embodiment of the invention is a process for catalytically cracking hydrocarbons comprising feeding a hydrocarbon feed stream to an FCC reactor and contacting the hydrocarbon feed stream with catalyst to catalytically crack the hydrocarbon feed stream to provide a cracked stream; disengaging the catalyst from the cracked stream; fractionating the cracked stream into products including a slurry oil stream from a bottom of a main fractionation column; separating the slurry oil stream into a cycle oil stream and a heavy stream under vacuum pressure; and hydrocracking at least a portion of the cycle oil stream over hydrocracking catalyst to provide an upgraded stream. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph further comprising heating the slurry oil stream before the separation step. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph further comprising recycling a portion of the heavy stream to the separation step. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph further comprising recycling a portion of the heavy stream from a separator bottoms line to a recycle inlet that is above an inlet of the slurry oil stream to the separator. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph further comprising condensing a separator overhead stream from an overhead of the separator, separating the condensed overhead stream in a receiver and taking the cycle oil stream from a bottom of a receiver. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph further comprising pulling a vacuum on a receiver overhead stream from the receiver and feeding it to a drain drum. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph further comprising refluxing a portion of the cycle oil stream to the separator vessel to a reflux inlet that is above the recycle inlet. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph wherein the hydrocracking step is conducted in a hydrocracking reactor in which hydrocracking is the predominant reaction. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph further comprising increasing a yield of diesel compared to a yield without hydrocracking the cycle oil stream. 
     A second embodiment of the invention is a process for catalytically cracking hydrocarbons comprising feeding a hydrocarbon feed stream to an FCC reactor and contacting the hydrocarbon feed stream with catalyst to catalytically crack the hydrocarbon feed stream to provide a cracked stream; disengaging the catalyst from the cracked stream; fractionating the cracked stream into products including a slurry oil stream from a bottom of a main fractionation column; separating the slurry oil stream into a separator overhead stream and a heavy stream under vacuum pressure in a separator vessel; condensing the separator overhead stream; separating the condensed overhead stream in a receiver; taking the cycle oil stream from a bottom of the receiver; and hydrocracking at least a portion of the cycle oil stream over hydrocracking catalyst to provide an upgraded product stream. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the second embodiment in this paragraph further comprising heating the slurry oil stream before the separation step. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the second embodiment in this paragraph further comprising recycling the heavy stream to the separation step. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the second embodiment in this paragraph further comprising recycling a portion of the heavy stream from a bottom of a separator vessel to a recycle inlet that is above an inlet of the slurry oil stream to the separator vessel. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the second embodiment in this paragraph further comprising pulling a vacuum on a receiver overhead stream from the receiver and feeding it to a drain drum. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the second embodiment in this paragraph further comprising refluxing a portion of the cycle oil stream to the separator vessel to a reflux inlet that is above the recycle inlet. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the second embodiment in this paragraph wherein the hydrocracking step is conducted in a hydrocracking reactor in which hydrocracking is the predominant reaction. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the second embodiment in this paragraph further comprising increasing a yield of diesel compared to a yield without hydrocracking the cycle oil stream. 
     A third embodiment of the invention is a process for catalytically cracking hydrocarbons comprising feeding a hydrocarbon feed stream to an FCC reactor and contacting the hydrocarbon feed stream with catalyst to catalytically crack the hydrocarbon feed stream to provide a cracked stream; disengaging the catalyst from the cracked stream; fractionating the cracked stream into products including a slurry oil stream from a bottom of a main fractionation column; separating the slurry oil stream into a cycle oil stream and a heavy stream under vacuum pressure in a separator vessel; recycling the heavy stream to the separation step; and hydrocracking at least a portion of the cycle oil stream over hydrocracking catalyst to provide an upgraded product stream. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the third embodiment in this paragraph further comprising condensing a separator overhead stream from a separator vessel; separating the condensed overhead stream in a receiver; and taking the cycle oil stream from a bottom of the receiver. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the third embodiment in this paragraph further comprising pulling a vacuum on a receiver overhead stream from the receiver. 
     A fourth embodiment of the invention is an apparatus for producing an upgraded product comprising an FCC reactor; a main fractionation column in communication with the FCC reactor; a separator in communication with a main bottoms line of the main fractionation column; a receiver in communication with a separator overhead line of the separator; a vacuum generation device in communication with a receiver overhead line of the receiver; and a receiver bottoms line of the receiver for providing an HCO process stream. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the fourth embodiment in this paragraph further comprising a hydrocracking unit in communication with the receiver bottoms line. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the fourth embodiment in this paragraph further comprising a hydrotreating reactor in communication with the receiver bottoms line and a hydrocracking reactor is in downstream communication with the hydrotreating reactor. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the fourth embodiment in this paragraph wherein the separator is a vacuum fractionation column. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the fourth embodiment in this paragraph further comprising a recycle line in downstream communication with a separator bottoms line and the separator is in downstream communication with the recycle line. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the fourth embodiment in this paragraph further comprising a recycle inlet to the separator for the recycle line, the recycle inlet being at a higher elevation than a feed inlet to the separator for the main bottoms line. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the fourth embodiment in this paragraph further comprising a reflux line in communication with the receiver bottoms line and the separator is in downstream communication with the reflux line. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the fourth embodiment in this paragraph further comprising a reflux inlet to the separator for the reflux line, the reflux inlet being at a higher elevation than a feed inlet to the separator for the main bottoms line and than a recycle inlet to the separator for the recycle line. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the fourth embodiment in this paragraph further comprising a heater in downstream communication with the main fractionation column and the separator is in downstream communication with the heater. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the fourth embodiment in this paragraph further comprising a condenser in communication with a separator overhead line. 
     A fifth embodiment of the invention is an apparatus for producing an upgraded product comprising an FCC reactor; a main fractionation column in communication with the FCC reactor; a separator in communication with a main bottoms line of the main fractionation column; a receiver in communication with a separator overhead line of the separator; an eductor in communication with a receiver overhead line of the receiver; a receiver bottoms line of the receiver for providing a HCO process stream; and a hydrocracking unit in downstream communication with the receiver bottoms line. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the fifth embodiment in this paragraph further comprising a hydrotreating reactor in communication with the receiver bottoms line and a hydrocracking reactor is in downstream communication with the hydrotreating reactor. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the fifth embodiment in this paragraph wherein the separator is a vacuum fractionation column. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the fifth embodiment in this paragraph further comprising a recycle line in downstream communication with a separator bottoms line and the separator is in downstream communication with the recycle line. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the fifth embodiment in this paragraph further comprising a reflux line in communication with the receiver bottoms line and the separator is in downstream communication with the reflux line. 
     A sixth embodiment of the invention is an apparatus for producing an upgraded product comprising an FCC reactor; a main fractionation column in communication with the FCC reactor; a separator in communication with a main bottoms line of the main fractionation column; and a hydrocracking unit in downstream communication with the separator. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the sixth embodiment in this paragraph further comprising a receiver in communication with a separator overhead line of the separator and the hydrocracking unit is in downstream communication with a receiver bottoms line of the receiver. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the sixth embodiment in this paragraph further comprising an eductor in communication with a receiver overhead line of the receiver. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the sixth embodiment in this paragraph wherein the separator is a vacuum fractionation column. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the sixth embodiment in this paragraph further comprising a recycle line in downstream communication with a separator bottoms line and the separator is in downstream communication with the recycle line. 
     A seventh embodiment of the invention is a process for recovering catalytically cracked hydrocarbons comprising feeding a hydrocarbon feed stream to an FCC reactor and contacting the hydrocarbon feed stream with catalyst to catalytically crack the hydrocarbon feed stream to provide a cracked stream; disengaging the catalyst from the cracked stream; fractionating the cracked stream into products including a slurry oil stream from a bottom of a main fractionation column; separating the slurry oil stream into a separator overhead stream and a heavy stream under vacuum pressure in a separator; condensing the separator overhead stream; separating the condensed overhead stream in a receiver; and recovering a cycle oil stream from a bottom of the receiver. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the seventh embodiment in this paragraph further comprising heating the slurry oil stream before the separation step. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the seventh embodiment in this paragraph further comprising recycling a portion of the heavy stream to the separation step. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the seventh embodiment in this paragraph further comprising recycling a portion of the heavy stream from a bottom of a separator vessel to a recycle inlet to the separator vessel that is above an inlet of the slurry oil stream. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the seventh embodiment in this paragraph further comprising refluxing a portion of the cycle oil stream to a reflux inlet to the separator vessel that is above the recycle inlet. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the seventh embodiment in this paragraph further comprising pulling a vacuum on a receiver overhead stream from the receiver and feeding it to a drain drum. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the seventh embodiment in this paragraph further comprising refluxing a portion of the cycle oil stream to the separator vessel. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the seventh embodiment in this paragraph further comprising recycling a portion of the heavy stream from a bottom of a separator vessel to a recycle inlet to the separator vessel that is above an inlet of the slurry oil stream and refluxing the portion of the cycle oil stream to a reflux inlet to the separator vessel that is above the recycle inlet. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the seventh embodiment in this paragraph further comprising recovering the heavy stream with an API that is lower than the slurry oil stream and producing carbon black feedstock. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the seventh embodiment in this paragraph further comprising recovering diesel from the cycle oil stream. 
     An eighth embodiment of the invention is a process for recovering catalytically cracking hydrocarbons comprising feeding a hydrocarbon feed stream to an FCC reactor and contacting the hydrocarbon feed stream with catalyst to catalytically crack the hydrocarbon feed stream to provide a cracked stream; disengaging the catalyst from the cracked stream; fractionating the cracked stream into products including a slurry oil stream from a bottom of a main fractionation column; separating the slurry oil stream into a separator overhead stream and a heavy stream under vacuum pressure in a separator vessel; condensing the separator overhead stream; separating the condensed overhead stream in a receiver; recovering a cycle oil stream from a bottom of the receiver; and obtaining an upgraded stream from the cycle oil stream. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the eighth embodiment in this paragraph further comprising heating the slurry oil stream before the separation step. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the eighth embodiment in this paragraph further comprising recycling a portion of the heavy stream to the separation step. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the eighth embodiment in this paragraph further comprising recycling a portion of the heavy stream from a bottom of a separator vessel to a recycle inlet to the separator vessel that is above an inlet of the slurry oil stream. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the eighth embodiment in this paragraph further comprising refluxing a portion of the cycle oil stream to a reflux inlet to the separator vessel that is above the recycle inlet. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the eighth embodiment in this paragraph further comprising pulling a vacuum on a receiver overhead stream from the receiver and feeding it to a drain drum. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the eighth embodiment in this paragraph further comprising refluxing a portion of the cycle oil stream to the separator vessel. 
     A ninth embodiment of the invention is a process for recovering catalytically cracked hydrocarbons comprising feeding a hydrocarbon feed stream to an FCC reactor and contacting the hydrocarbon feed stream with catalyst to catalytically crack the hydrocarbon feed stream to provide a cracked stream; disengaging the catalyst from the cracked stream; fractionating the cracked stream into products including a slurry oil stream from a bottom of a main fractionation column; separating the slurry oil stream into a separator overhead stream and a heavy stream under vacuum pressure in a separator vessel; condensing the separator overhead stream; separating the condensed overhead stream in a receiver; recovering a cycle oil stream from a bottom of the receiver; pulling a vacuum on a receiver overhead stream from the receiver; and obtaining an upgraded stream from the cycle oil stream. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the ninth embodiment in this paragraph further comprising heating the slurry oil stream before the separation step. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the ninth embodiment in this paragraph further comprising recovering the heavy stream with an API that is lower than the slurry oil stream and producing carbon black feedstock. 
     A tenth embodiment of the invention is a process for catalytically cracking hydrocarbons comprising feeding a hydrocarbon feed stream to an FCC reactor and contacting the hydrocarbon feed stream with catalyst to catalytically crack the hydrocarbon feed stream to provide a cracked stream; disengaging the catalyst from the cracked stream; fractionating the cracked stream into products including a slurry oil stream from a bottom of a main fractionation column; separating the slurry oil stream into a cycle oil process stream and a heavy stream under vacuum pressure in a separator; and refluxing the cycle oil process stream to the main fractionation column. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the tenth embodiment in this paragraph further comprising hydrocracking a cycle oil stream from the main fractionation column. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the tenth embodiment in this paragraph further comprising heating the slurry oil stream before the separation step. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the tenth embodiment in this paragraph further comprising condensing a separator overhead stream from an overhead of the separator, separating the condensed overhead stream in a receiver and taking the cycle oil process stream from a bottom of the receiver. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the tenth embodiment in this paragraph further comprising pulling a vacuum on a receiver overhead stream from the receiver and feeding it to a drain drum. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the tenth embodiment in this paragraph further comprising withdrawing a cycle oil stream from the main fractionation column, hydrocracking a portion of the cycle oil stream and returning another portion of the cycle oil stream to main fractionation column. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the tenth embodiment in this paragraph further comprising withdrawing the cycle oil stream from the main fractionation column from an outlet that is at a higher elevation than an inlet of the cycle oil process stream refluxed to the main fractionation column. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the tenth embodiment in this paragraph further comprising cooling the another portion of the cycle oil stream before it is returned to the main fractionation column. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the tenth embodiment in this paragraph further comprising recovering a diesel stream and/or an aromatics stream from the hydrocracked cycle oil stream. 
     An eleventh embodiment of the invention is a process for catalytically cracking hydrocarbons comprising feeding a hydrocarbon feed stream to an FCC reactor and contacting the hydrocarbon feed stream with catalyst to catalytically crack the hydrocarbon feed stream to provide a cracked stream; disengaging the catalyst from the cracked stream; fractionating the cracked stream into products including a slurry oil stream from a bottom of a main fractionation column; separating the slurry oil stream into a cycle oil process stream and a heavy stream under vacuum pressure in a separator; and refluxing the cycle oil process stream to the main fractionation column; and hydrocracking a cycle oil stream from the main fractionation column. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the eleventh embodiment in this paragraph further comprising condensing a separator overhead stream from an overhead of the separator, separating the condensed overhead stream in a receiver and taking the cycle oil process stream from a bottom of the receiver. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the eleventh embodiment in this paragraph further comprising pulling a vacuum on a receiver overhead stream from the receiver and feeding it to a drain drum. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the eleventh embodiment in this paragraph further comprising withdrawing a cycle oil stream from the main fractionation column, hydrocracking a portion of the cycle oil stream and returning another portion of the cycle oil stream to main fractionation column. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the eleventh embodiment in this paragraph further comprising withdrawing the cycle oil stream from the main fractionation column from an outlet that is at a higher elevation than an inlet of the cycle oil process stream refluxed to the main fractionation column. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the eleventh embodiment in this paragraph further comprising recovering a diesel stream and/or an aromatics stream from the hydrocracked cycle oil stream. 
     A twelfth embodiment of the invention is a process for catalytically cracking hydrocarbons comprising feeding a hydrocarbon feed stream to an FCC reactor and contacting the hydrocarbon feed stream with catalyst to catalytically crack the hydrocarbon feed stream to provide a cracked stream; disengaging the catalyst from the cracked stream; fractionating the cracked stream into products including a slurry oil stream from a bottom of a main fractionation column; separating the slurry oil stream into a cycle oil process stream and a heavy stream under vacuum pressure in a separator; refluxing the cycle oil process stream to the main fractionation column; hydrocracking a cycle oil stream from the main fractionation column; and recovering a diesel stream and/or an aromatics stream from the hydrocracked cycle oil stream. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the twelfth embodiment in this paragraph further comprising condensing a separator overhead stream from an overhead of the separator, separating the condensed overhead stream in a receiver and taking the cycle oil process stream from a bottom of the receiver. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the twelfth embodiment in this paragraph further comprising withdrawing the cycle oil stream from the main fractionation column, hydrocracking a portion of the cycle oil stream and returning another portion of the cycle oil stream to main fractionation column. 
     A thirteenth embodiment of the invention is an apparatus for producing upgraded product comprising an FCC reactor; a main fractionation column in communication with the FCC reactor; a vacuum separator in communication with a main bottoms line of the main fractionation column; and a hydrocracking unit in communication with a side outlet of the main fractionation column. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the thirteenth embodiment in this paragraph wherein the main fractionation column is in downstream communication with the vacuum separator. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the thirteenth embodiment in this paragraph further comprising a reflux inlet to the main fractionation column in downstream communication with the vacuum separator, the reflux inlet being at a lower elevation than the side outlet of the main fractionation column. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the thirteenth embodiment in this paragraph wherein the main fractionation column is in downstream communication with a separator overhead line of the vacuum separator. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the thirteenth embodiment in this paragraph further comprising a receiver in communication with a separator overhead line of the vacuum separator; and the main fractionation column in downstream communication with a receiver bottoms line of the receiver. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the thirteenth embodiment in this paragraph wherein the reflux inlet to the main fractionation column is for the receiver bottoms line. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the thirteenth embodiment in this paragraph further comprising a cooler in communication with a separator overhead line. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the thirteenth embodiment in this paragraph further comprising an eductor in communication with a receiver overhead line of the receiver. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the thirteenth embodiment in this paragraph further comprising a hydrotreating reactor in communication with the side outlet of the main fractionation column and a hydrocracking reactor is in downstream communication with the hydrotreating reactor. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the thirteenth embodiment in this paragraph further comprising a return line to the main fractionation column in communication with the side outlet. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the thirteenth embodiment in this paragraph further comprising a cooler on the return line. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the thirteenth embodiment in this paragraph further comprising a heater in downstream communication with the main fractionation column and the vacuum separator is in downstream communication with the heater. 
     A fourteenth embodiment of the invention is an apparatus for producing upgraded product comprising an FCC reactor; a main fractionation column in communication with the FCC reactor; a vacuum separator in communication with a main bottoms line of the main fractionation column; the main fractionation column in downstream communication with the vacuum separator; and a hydrocracking unit in communication with a side outlet of the main fractionation column. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the fourteenth embodiment in this paragraph further comprising a reflux inlet to the main fractionation column in downstream communication with the vacuum separator, the reflux inlet being at a lower elevation than the side outlet of the main fractionation column. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the fourteenth embodiment in this paragraph wherein the main fractionation column is in downstream communication with a separator overhead line of the vacuum separator. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the fourteenth embodiment in this paragraph further comprising a receiver in communication with a separator overhead line of the vacuum separator; and the main fractionation column in downstream communication with a receiver bottoms line of the receiver. 
     A fifteenth embodiment of the invention is an apparatus for producing upgraded product comprising an FCC reactor; a main fractionation column in communication with the FCC reactor; a vacuum separator in communication with a main bottoms line of the main fractionation column; the main fractionation column in downstream communication with a separator overhead line of the vacuum separator; and a hydrocracking unit in communication with a side outlet of the main fractionation column. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the fifteenth embodiment in this paragraph further comprising a reflux inlet to the main fractionation column in downstream communication with the vacuum separator, the reflux inlet being at a lower elevation than the side outlet of the main fractionation column. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the fifteenth embodiment in this paragraph further comprising a receiver in communication with the separator overhead line of the vacuum separator; and the main fractionation column in downstream communication with a receiver bottoms line of the receiver. An embodiment of the invention is one, any or all of prior embodiments in this paragraph up through the fifteenth embodiment in this paragraph further comprising a hydrotreating reactor in communication with the side outlet of the main fractionation column and a hydrocracking reactor is in downstream communication with the hydrotreating reactor. 
     Without further elaboration, it is believed that using the preceding description that one skilled in the art can utilize the present invention to its fullest extent and easily ascertain the essential characteristics of this invention, without departing from the spirit and scope thereof, to make various changes and modifications of the invention and to adapt it to various usages and conditions. The preceding preferred specific embodiments are, therefore, to be construed as merely illustrative, and not limiting the remainder of the disclosure in any way whatsoever, and that it is intended to cover various modifications and equivalent arrangements included within the scope of the appended claims. 
     In the foregoing, all temperatures are set forth in degrees Celsius and, all parts and percentages are by weight, unless otherwise indicated.