Abstract:
A process and apparatus provides for blending a heavy naphtha stream with a diesel stream to increase the yield of diesel. The diesel stream is recovered separately from a kerosene stream to leave the kerosene stream undiminished. The blended diesel provides a valuable composition.

Description:
FIELD OF THE INVENTION 
     The field of the invention is the recovery of hydroprocessed hydrocarbon streams. 
     BACKGROUND OF THE INVENTION 
     Hydroprocessing can include processes which convert hydrocarbons in the presence of hydroprocessing catalyst and hydrogen to more valuable products. 
     Hydrocracking is a hydroprocessing process in which hydrocarbons crack 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 beds of the same or different catalyst. Hydrotreating is a hydroprocessing process used to remove heteroatoms such as sulfur and nitrogen from hydrocarbon streams to meet fuel specifications and to saturate olefinic compounds. Slurry hydrocracking is a slurried catalytic process used to crack residue feeds to gas oils and fuels. 
     Hydroprocessing recovery units typically include a stripper for stripping hydroprocessed effluent with a stripping medium such as steam to remove unwanted hydrogen sulfide. The stripped effluent then is heated in a fired heater to fractionation temperature before entering a product fractionation column to recover products such as naphtha, kerosene and diesel. 
     Maximizing diesel production is desired in several regions of the world due to its increasing demand as a motor fuel. Hydrocracking units are most effective in producing diesel. The common way to increase diesel production is to add kerosene to diesel but kerosene is the primary component for jet fuel which is a highly profitable fuel. Thus, increasing diesel production in the conventional way is at the expense of reducing jet fuel, so there is little to no monetary advantage for moving the kerosene cut into the diesel cut. Moreover, only so much heavy naphtha can be moved into the kerosene cut without diminishing jet fuel performance. 
     There is a continuing need, therefore, for improved methods of recovering fuel products from hydroprocessed effluents and for increasing diesel recovery. 
     BRIEF SUMMARY OF THE INVENTION 
     Applicants have discovered a blend composition of heavy naphtha and diesel with little or no kerosene that improves the diesel recovery while preserving kerosene for jet fuel. The invention comprises a process and apparatus for making the blend composition. 
     In a process embodiment, the invention comprises a process for separating hydroprocessed effluent comprising separating a hydroprocessed effluent into a heavy naphtha stream having an initial boiling point temperature between about 250° and about 280° F., a kerosene stream having an initial boiling point temperature between about 280° and about 420° F. and a diesel stream having an initial boiling point temperature between about 380° and about 440° F.; and blending the heavy naphtha stream with the diesel stream to provide a blended diesel stream. 
     In an additional process embodiment, the invention comprises a process for separating hydroprocessed effluent comprising stripping a hydroprocessed effluent stream; separating a stripped hydroprocessed effluent into a heavy naphtha stream having an initial boiling point temperature between about 250° and about 280° F., a kerosene stream having an initial boiling point temperature between about 280° and about 420° F. and a diesel stream having an initial boiling point temperature above 380° F.; and blending the heavy naphtha stream with the diesel stream to provide a blended diesel stream. 
     In a further process embodiment, the invention comprises a process for separating hydroprocessed effluent comprising separating a hydroprocessed effluent into a heavy naphtha stream having an initial boiling point temperature between about 250° and about 280° F., a kerosene stream having an initial boiling point temperature between about 280° and about 420° F. and a diesel stream having an initial boiling point temperature above 380° F.; and blending the heavy naphtha stream with the diesel stream to provide a blended diesel stream so that the blended diesel stream comprises 1-7 wt-% heavy naphtha. 
     In an apparatus embodiment, the invention comprises a hydrocracking recovery apparatus comprising a fractionation column for separating a hydroprocessed stream; an overhead line from an overhead of said fractionation column; a kerosene line from a kerosene outlet in a side of said fractionation column; a diesel line from a diesel outlet in the side of said fractionation column below said kerosene outlet; and said diesel line is in communication with said overhead line. 
     In an additional apparatus embodiment, the invention comprises a hydrocracking recovery apparatus comprising a hydrocracking reactor; a fractionation column in communication with said hydrocracking reactor for separating a hydroprocessed stream; an overhead line taken from an overhead of said fractionation column; a kerosene line taken from a kerosene outlet in a side of said fractionation column; a diesel line taken from a diesel outlet in the side of said fractionation column below said kerosene outlet; and said diesel line is in communication with said overhead line. 
     In a further apparatus embodiment, the invention comprises a hydrocracking recovery apparatus comprising a hydrocracking reactor; a stripper column in communication with said hydrocracking reactor; a fractionation column in communication with a bottom line from said stripper column; an overhead line taken from an overhead of said fractionation column; a kerosene line taken from a kerosene outlet in a side of said fractionation column; a diesel line taken from a diesel outlet in the side of said fractionation column below said kerosene outlet; and said diesel line is in communication with said overhead line. 
     In a composition embodiment, the invention comprises a fuel composition comprising a hydrocarbon material having an initial boiling point temperature in range between about 250° and about 300° F., a T10 temperature range between about 360° and about 450° F. and a T95 temperature range between about 600° and about 700° F. 
     In an additional composition embodiment, the invention comprises a fuel composition comprising a hydrocarbon material having an initial boiling point temperature range between about 250° and about 300° F., a T10 temperature range between about 380° and about 450° F. and a T95 temperature range between about 600° and about 700° F. 
     In a further composition embodiment, the invention comprises fuel composition comprising a hydrocarbon material having an initial boiling point temperature range between about 250° and about 300° F., a T10 temperature range between about 400° and about 450° F. and a T95 temperature range between about 600° and about 700° F. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a simplified process flow diagram of an embodiment of the present invention. 
         FIG. 2  is a simplified process flow diagram of an alternative embodiment to the 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 “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 bottom temperature is the liquid bottom outlet temperature. Overhead lines and bottoms lines refer to the net lines from the column downstream of any reflux or reboil to the column. Stripper 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 D2892 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. 
     ASTM D-86 method is used for modeling atmospheric distillation products including naphtha, kerosene diesel and atmospheric gas oil. In the method, a sample stream is heated in a graduated cylinder. As the sample gets hotter, more of the sample flashes off. Each flash temperature corresponding to a boiling percent is recorded. As used herein, the term “initial boiling point” (IBP) is the distillation temperature at which 0.5 wt-% of the material is vaporized. As used herein, the term “T10” is the distillation temperature at which 10 wt-% of the material is vaporized. As used herein, the term “T95” is the distillation temperature at which 95 wt-% of the material is vaporized. 
     As used herein, the term “diesel boiling range” means hydrocarbons boiling in the range of between about 450° F. (232° C.) and about 750° F. (399° C.) using the TBP distillation method. “Diesel boiling range” may also have an IBP of between about 380° F. (193° C.) and 440° F. (226° C.) using ASTM D-86 method. 
     As used herein, the term “kerosene boiling range” means hydrocarbons boiling in the range of between about 380° F. (193° C.) and about 450° F. (232° C.) using the TBP distillation method. “Kerosene boiling range” may also have an IBP of between about 280° F. (137° C.) and 420° F. (216° C.) using ASTM D-86 method. 
     As used herein, the term “naphtha boiling range” means hydrocarbons boiling in the range of between about 70° F. (21° C.) and about 380° F. (193° C.) using the TBP distillation method. 
     As used herein, the term “heavy naphtha boiling range” means hydrocarbons boiling in the range of between about 200° F. (93° C.) and about 380° F. (193° C.). 
     As used herein, the term “heavy-heavy naphtha boiling range” means hydrocarbons boiling in the range of between about 300° F. (149° C.) and about 380° F. (193° C.) using the TBP distillation method. “Heavy-heavy naphtha boiling range” may also have an IBP of between about 250° F. (121° C.) and 280° F. (137° C.) using ASTM D-86 method. 
     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 and a fractionation column are types of separators. 
     DETAILED DESCRIPTION 
     In this invention, heavy naphtha is separated from a naphtha stream and is blended with a diesel stream substantially devoid of kerosene, so it is has an elevated flashpoint. According to the invention, jet fuel can be maintained at the desirable level while diesel can be maximized by blending with heavy naphtha. At the same time, flash points of jet fuel and diesel can be maintained at specifications. As the result, this invention could enhance diesel production by 1-7% and thus improve refining economic margin by $40 million per year for a 200,000 barrel-per-day refinery. 
     The apparatus and process  10  for hydroprocessing and recovering hydrocarbons comprise a hydrocracking unit  12  and a product recovery unit  14 . A hydrocarbon stream in hydrocarbon line  16  and a make-up hydrogen stream in hydrogen make-up line  18  are fed to the hydrocracking unit  12 . Hydroprocessing effluent is fractionated in the product recovery unit  14 . 
     A hydrogen stream in hydrogen line  76  supplemented by make-up hydrogen from line  18  may join the hydrocarbon feed stream in feed line  16  to provide a hydrocracking feed stream in feed line  20 . The hydrocracking feed stream in line  20  may be heated by heat exchange and in a fired heater  22  and fed to the hydrocracking reactor  24 . 
     In one aspect, the process and apparatus described herein are particularly useful for hydrocracking a hydrocarbonaceous feedstock. Illustrative hydrocarbon feedstocks include hydrocarbonaceous streams having components boiling above about 550° F. (288° C.), such as atmospheric gas oils, vacuum gas oil (VGO) boiling between about 600° F. (315° C.) and about 1050° F. (565° C.), deasphalted oil, coker distillates, straight run distillates, pyrolysis-derived oils, high boiling synthetic oils, cycle oils, hydrocracked feeds, catalytic cracker distillates, atmospheric residue boiling at or above about 650° F. (343° C.) and vacuum residue boiling above about 950° F. (510° C.). 
     Hydroprocessing that occurs in the hydroprocessing unit may be hydrocracking or hydrotreating. Hydrocracking refers to a process in which hydrocarbons crack in the presence of hydrogen to lower molecular weight hydrocarbons. Hydrocracking is the preferred process in the hydroprocessing unit  12 . Consequently, the term “hydroprocessing” will include the term “hydrocracking” herein. Hydrocracking also includes slurry hydrocracking in which resid feed is mixed with catalyst and hydrogen to make a slurry and is cracked to lower boiling products. 
     The hydrocracking reactor  24  may be a fixed bed reactor that comprises one or more vessels, single or multiple beds of catalyst in each vessel, and various combinations of hydrotreating catalyst and/or hydrocracking catalyst in one or more vessels. It is contemplated that the hydrocracking reactor  24  be operated in a continuous liquid phase in which the volume of the liquid hydrocarbon feed is greater than the volume of the hydrogen gas. The hydrocracking reactor  24  may also be operated in a conventional continuous gas phase, a moving bed or a fluidized bed hydrocracking reactor. 
     The hydrocracking reactor  24  may provide total conversion of at least about 20 vol-% and typically greater than about 60 vol-% of the hydrocarbon feed to products boiling below the diesel cut point. A hydrocracking reactor may operate at partial conversion of more than about 50 vol-% or full conversion of at least about 90 vol-% of the feed based on total conversion. A hydrocracking reactor may be operated at mild hydrocracking conditions which will provide about 20 to about 60 vol-%, preferably about 20 to about 50 vol-%, total conversion of the hydrocarbon feed to product boiling below the diesel cut point. 
     The first vessel or bed in the hydrocracking reactor  24  may include hydrotreating catalyst for the purpose of saturating, demetallizing, desulfurizing or denitrogenating the hydrocarbon feed before it is hydrocracked with hydrocracking catalyst in subsequent vessels or beds in the hydrocracking reactor  24 . If the hydrocracking reactor is a mild hydrocracking reactor, it may contain several beds of hydrotreating catalyst followed by fewer beds of hydrocracking catalyst. 
     A hydrocracking catalyst may utilize amorphous silica-alumina bases or low-level zeolite bases combined with one or more Group VIII or Group VIB metal hydrogenating components if mild hydrocracking is desired to produce a balance of middle distillate and gasoline. In another aspect, when middle distillate is significantly preferred in the converted product over gasoline production, partial or full hydrocracking may be performed in the first hydrocracking reactor  24  with a catalyst which comprises, in general, any crystalline zeolite cracking base upon which is deposited a Group VIII metal hydrogenating component. Additional hydrogenating components may be selected from Group VIB for incorporation with the zeolite base. 
     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 (10 −10  meters). It is preferred to employ zeolites having a relatively high silica/alumina mole 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 8-12 Angstroms (10 −10  meters), wherein the silica/alumina mole ratio is about 4 to 6. One example of a zeolite falling in the preferred group is synthetic Y molecular sieve. 
     The natural 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 percent, and preferably at least about 20 percent, 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 percent of the ion exchange capacity is satisfied by hydrogen ions. 
     The active metals employed in the preferred hydrocracking catalysts of the present invention as hydrogenation components 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 hydrogenating 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 method for incorporating the hydrogenating metal is to contact the base material with an aqueous solution of a suitable compound of the desired metal wherein the metal is present in a cationic form. Following addition of the selected hydrogenating metal or metals, the resulting catalyst powder is then filtered, dried, pelleted with added lubricants, binders or the like if desired, and calcined in air at temperatures of, e.g., about 700° F. (371° C.) to about 1200° F. (648° C.) in order to activate the catalyst and decompose ammonium ions. Alternatively, the base component may first be pelleted, followed by the addition of the hydrogenating component and activation by calcining. 
     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, crystalline chromosilicates and other crystalline silicates. Crystalline chromosilicates are more fully described in U.S. Pat. No. 4,363,718. 
     By one approach, the hydrocracking conditions may include a temperature from about 550° F. (290° C.) to about 875° F. (468° C.), preferably 650° F. (343° C.) to about 833° F. (445° C.), a pressure from about 700 psig (4.8 MPa) (gauge) to about 3000 psig (20.7 MPa) (gauge), a liquid hourly space velocity (LHSV) from about 1.0 to less than about 2.5 hr −1  and a hydrogen rate of about 2,500 scf/bbl (421 Nm 3 /m 3 ) to about 15,000 scf/bbl (2,527 Nm 3 /m 3 ) oil. If mild hydrocracking is desired, conditions may include a temperature from about 600° F. (315° C.) to about 825° F. (441° C.), a pressure from about 800 psig (5.5 MPa) (gauge) to about 2000 psig (13.8 MPa) (gauge) or more typically about 1000 psig (6.9 MPa) (gauge) to about 1600 psig (11.0 MPa) (gauge), a liquid hourly space velocity (LHSV) from about 0.5 to about 2 hr −1  and preferably about 0.7 to about 1.5 hr −1  and a hydrogen rate of about 2,500 scf/bbl (421 Nm 3 /m 3 ) oil to about 10,000 scf/bbl (1,685 Nm 3 /m 3 ) oil. 
     A hydrocracking effluent exits the hydrocracking reactor  24  and is transported in hydrocracking effluent line  26 . The hydrocracking effluent comprises material that will become a relatively cold hydrocracking effluent stream and a relatively hot hydrocracking effluent stream. The hydrocracking unit may comprise one or more separators for separating the hydrocracking effluent stream into a cold hydrocracking effluent stream and hot hydrocracking effluent stream. 
     The hydrocracking effluent in hydrocracking effluent line  26  may in an aspect be heat exchanged with the hydrocracking feed stream in line  20  to be cooled before entering a hot separator  30 . The hot separator separates the hydrocracking effluent to provide a vaporous hydrocarbonaceous hot separator overhead stream in an overhead line  32  comprising a portion of a cold hydroprocessed effluent stream and a liquid hydrocarbonaceous hot separator bottoms stream in a bottoms line  34  comprising a portion of a cold hydroprocessed effluent stream and still a portion of a hot hydroprocessed effluent stream. The hot separator  30  in the hydrocracking section  12  is in downstream communication with the hydrocracking reactor  24 . The hot separator  30  operates at about 350° F. (177° C.) to about 700° F. (371° C.) and preferably operates at about 450° F. (232° C.) to about 600° F. (315° C.). The hot separator  30  may be operated at a slightly lower pressure than the hydrocracking reactor  24  accounting for pressure drop of intervening equipment. The hot separator may be operated at pressures between about 493 psig (3.4 MPa) (gauge) and about 2959 psig (20.4 MPa) (gauge). 
     The vaporous hydrocarbonaceous hot separator overhead stream in the overhead line  32  may be cooled before entering a cold separator  36 . As a consequence of the reactions taking place in the hydrocracking reactor  24  wherein nitrogen, chlorine and sulfur are removed from the feed, ammonia and hydrogen sulfide are formed. At a characteristic temperature, ammonia and hydrogen sulfide will combine to form ammonium bisulfide and ammonia and chlorine will combine to form ammonium chloride. Each compound has a characteristic sublimation temperature that may allow the compound to coat equipment, particularly heat exchange equipment, impairing its performance. To prevent such deposition of ammonium bisulfide or ammonium chloride salts in the line  32  transporting the hot separator overhead stream, a suitable amount of wash water (not shown) may be introduced into line  32  upstream at a point in line  32  where the temperature is above the characteristic sublimation temperature of either compound. 
     The cold separator  36  serves to separate hydrogen from hydrocarbon in the hydrocracking effluent for recycle to the hydrocracking reactor  24  in the overhead line  38 . The vaporous hydrocarbonaceous hot separator overhead stream may be separated in the cold separator  36  to provide a vaporous cold separator overhead stream comprising a hydrogen-rich gas stream in an overhead line  38  and a liquid cold separator bottoms stream in the bottoms line  40  comprising a portion of the cold hydrocracking effluent stream. The cold separator  36 , therefore, is in downstream communication with the overhead line  32  of the hot separator  30  and the hydrocracking reactor  24 . The cold separator  36  may be operated at about 100° F. (38° C.) to about 150° F. (66° C.), suitably about 115° F. (46° C.) to about 145° F. (63° C.), and just below the pressure of the hydrocracking reactor  24  and the hot separator  30  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 may be operated at pressures between about 435 psig (3 MPa) (gauge) and about 2,901 psig (20 MPa) (gauge). The cold separator  36  may also have a boot for collecting an aqueous phase in line  42 . 
     The liquid hydrocarbonaceous stream in the hot separator bottoms line  34  may be fractionated as hot hydrocracking effluent stream in the product recovery unit  14 . In an aspect, the liquid hydrocarbonaceous stream in the bottoms line  34  may be let down in pressure and flashed in a hot flash drum  44  to provide a hot flash overhead stream of light ends in an overhead line  46  comprising a portion of the cold hydroprocessed effluent stream and a heavy liquid stream in a bottoms line  48  comprising at least a portion of the hot hydroprocessed effluent stream. The hot flash drum  44  may be any separator that splits the liquid hydrocracking effluent into vapor and liquid fractions. The hot flash drum  44  may be operated at the same temperature as the hot separator  30  but at a lower pressure of between about 300 psig (2.1 MPa) (gauge) and about 1000 psig (6.9 MPa) (gauge), suitably less than about 500 psig (3.4 MPa) (gauge). The heavy liquid stream in bottoms line  48  may be further fractionated in the product recovery unit  14 . In an aspect, the heavy liquid stream in bottoms line  48  may be introduced into a stripper column  50  and comprise at least a portion, and suitably all, of a relatively hot hydrocracking effluent stream. The stripper column  50  is in downstream communication with a bottom of the hot flash drum  44  via bottoms line  48 . 
     In an aspect, the liquid hydrocracking effluent stream in the cold separator bottoms line  40  may be fractionated as a cold hydrocracking effluent stream in the product recovery unit  14 . In a further aspect, the cold separator liquid bottoms stream may be let down in pressure and flashed in a cold flash drum  52  to separate the cold separator liquid bottoms stream in bottoms line  40 . The cold flash drum  52  may be any separator that splits hydrocracking effluent into vapor and liquid fractions. The cold flash drum may be in communication with a bottom of the cold separator  36  via bottoms line  40 . The stripper column  50  may be in downstream communication with a bottoms line  56  of the cold flash drum  52 . 
     In a further aspect, the vaporous hot flash overhead stream in overhead line  46  may be fractionated as a cold hydrocracking effluent stream in the product recovery unit  14 . In a further aspect, the hot flash overhead stream may be cooled and also separated in the cold flash drum  52 . The cold flash drum  52  may separate the cold separator liquid bottoms stream in line  40  and hot flash vaporous overhead stream in overhead line  46  to provide a cold flash overhead stream in overhead line  54  and a cold flash bottoms stream in a bottoms line  56  comprising at least a portion of a cold hydroprocessed effluent stream. The cold flash bottoms stream in bottoms line  56  comprises at least a portion, and suitably all, of the cold hydroprocessed effluent stream. In an aspect, the stripper column  50  is in downstream communication with the cold flash drum  52  via bottoms line  56 . The cold flash drum  52  may be in downstream communication with the bottoms line  40  of the cold separator  50 , the overhead line  46  of the hot flash drum  44  and the hydrocracking reactor  24 . The cold separator bottoms stream in bottoms line  40  and the hot flash overhead stream in overhead line  46  may enter into the cold flash drum  52  either together or separately. In an aspect, the hot flash overhead line  46  joins the cold separator bottoms line  40  and feeds the hot flash overhead stream and the cold separator bottoms stream together to the cold flash drum  52 . The cold flash drum  52  may be operated at the same temperature as the cold separator  50  but typically at a lower pressure of between about 300 psig (2.1 MPa) (gauge) and about 1000 psig (7.0 MPa) (gauge) and preferably no higher than 450 psig (3.1 MPa) (gauge). The aqueous stream in line  42  from the boot of the cold separator may also be directed to the cold flash drum  52 . A flashed aqueous stream is removed from a boot in the cold flash drum  52  in line  62 . 
     The vaporous cold separator overhead stream comprising hydrogen in the overhead line  38  is rich in hydrogen. The cold separator overhead stream in overhead line  38  may be passed through a trayed or packed scrubbing tower  28  where it is scrubbed by means of a scrubbing liquid such as an aqueous amine solution in line  27  to remove hydrogen sulfide and ammonia. The spent scrubbing liquid in line  29  may be regenerated and recycled back to the scrubbing tower  64 . The scrubbed hydrogen-rich stream emerges from the scrubber via line  70  and may be compressed in a recycle compressor  72  to provide a recycle hydrogen stream in line  74  which is a compressed vaporous hydrocracking effluent stream. The recycle compressor  72  may be in downstream communication with the hydrocracking reactor  24 . The recycle hydrogen stream in line  74  may be supplemented with make-up stream  18  to provide the hydrogen stream in hydrogen line  76 . A portion of the material in line  74  may be routed to the intermediate catalyst bed outlets in the hydrocracking reactor  24  to control the inlet temperature of the subsequent catalyst bed (not shown). 
     In the embodiment of  FIG. 1 , the product recovery section  14  may include a stripper column  50 , a debutanizer column  80 , a product fractionation column  90  and a separator  140 . The stripper  50  is in downstream communication with the hydrocracking reactor  24  for stripping the hydrocracking effluent stream which is a portion of the hydrocracking effluent stream in hydrocracking effluent line  26 . In  FIG. 1 , both the cold hydroprocessed effluent stream  56  and the hot hydroprocessed effluent stream  48  are stripped in the stripper column  50 . However, more than one stripper column may be used to strip respective hydroprocessed effluent streams. 
     The cold hydrocracking effluent stream which in an aspect may be in the cold flash bottoms line  56  may be heated and fed to the stripper column  50  near a top of the column. The hot hydrocracking effluent stream which may be in the hot flash bottoms line  48  may be fed to the stripper column  50  at a location below an inlet for the cold hydrocracking effluent stream. The hydrocracking effluent streams may be stripped in the stripper column  50  with a stripping media which is an inert gas such as steam from line  58  to provide an overhead vapor stream of light naphtha, LPG, hydrogen, hydrogen sulfide, stripping media and other gases in an overhead line  60 . At least a portion of the hot vapor stream may be condensed and separated in a receiver  64 . An overhead line  66  from the receiver  64  carries vaporous off gas for further treating. Unstabilized liquid naphtha from the bottoms of the receiver  64  may be split between a reflux portion in line  67  refluxed to the top of the stripper column  50  and a net overhead stream which may be transported in product line  68  to further fractionation such as in a debutanizer column  80 . The stripper column  50  may be operated with a bottoms temperature between about 320° F. (160° C.) and about 680° F. (360° C.) and an overhead pressure of about 73 psig (0.5 MPa) (gauge) to about 292 psig (2.0 MPa) (gauge). The temperature in the overhead receiver  98  ranges from about 100° F. (38° C.) to about 150° F. (66° C.) and the pressure is essentially the same as in the overhead of the stripper column  50 . 
     A stripped hydroprocessed stream is produced in bottoms line  72 . At least a portion of the stripped stream in bottoms line  72  may be fed to the product fractionation column  90 . Consequently, the product fractionation column  90  is in downstream communication with the bottoms line  72  of the stripper column  50 . A fired heater  74  in downstream communication with the bottoms line  72  may heat at least a portion of the stripped hydroprocessed stream before it enters the product fractionation column  90  in line  74 . 
     The product fractionation column  90  may be in downstream communication with the stripper column  50  for separating the stripped hydroprocessed stream into product streams. The product fractionation column  90  may strip the stripped stream in line  72  with stripping media such as steam from line  78  to provide several product streams. The product streams may include an overhead heavy naphtha stream in overhead line  120  from an overhead of the product fractionation column  90 , a kerosene stream having an initial boiling point temperature between about 280° F. (137° C.) and about 420° F. (216° C.) in a kerosene line  122  from a kerosene side outlet  122   a , a diesel stream having an initial boiling point temperature above 380° F. (193° C.) and no more than 440° F. (226° C.) in a diesel line  124  from a diesel side outlet  124   a , which is below the kerosene side cut outlet  122   a  and an unconverted oil stream boiling above the diesel range in a bottoms line  126  which may be suitable for further processing, such as in an FCC unit or by recycle to the hydrocracking reactor  24 . Heat may be removed from the product fractionation column  90  by cooling the kerosene in line  122  and diesel in line  124  and sending a portion of each cooled stream back to the column. The overhead heavy naphtha stream in line  120  may be condensed and separated in a receiver  128  with liquid being refluxed back to the product fractionation column  90 . A net heavy naphtha stream boiling between about 200° F. (93° C.) and about 380° F. (193° C.) TBP is recovered in a net overhead line  130 . 
     The product fractionation column  90  may be operated with a bottoms temperature between about 550° F. (288° C.) and about 700° F. (370° C.), preferably about 650° F. (343° C.) and at an overhead pressure between about 4 psig (30 kPa) (gauge) to about 29 psig (200 kPa) (gauge). A portion of the unconverted oil in the bottoms line  126  may be reboiled and returned to the product fractionation column  90  instead of being stripped with inert gas such as steam in line  78 . 
     In an aspect, the diesel line  124  is in communication with net overhead line  130  to afford blending the heavy naphtha stream with the diesel stream to provide a blended diesel stream in line  132 . The diesel line  124  may be out of communication with the kerosene line  122 . The kerosene stream is separately recovered and may be isolated from the diesel stream. In an aspect, the heavy naphtha stream comprises about 1 to about 7 wt-%, optimally about 2 to about 6 wt-% and preferably about 3 to about 5 wt-% of the blended diesel stream. In the embodiment of  FIG. 1 , a separator  140 , which may be a fractionation column, separates the heavy naphtha stream into a heavy-heavy naphtha stream before it is blended with the diesel stream. 
     The net heavy naphtha condensed in the net overhead line  130  is fed to the separator  140  which is in downstream communication with the hydrocracking reactor  12 , the stripper column  50  and the product fractionation column  90 . The separator  140  separates the heavy naphtha stream to provide a net off-gas stream in line  142  and a condensed net medium naphtha stream in line  144  boiling in the range of about 180° F. (82° C.) to about 300° F. (149° C.) TBP. In a bottoms line  146  from the separator  140 , a heavy-heavy naphtha stream is produced which is excellent for blending with the diesel stream in line  124 . The heavy-heavy naphtha stream may have an initial boiling point temperature between about 250° F. (121° C.) and about 280° F. (137° C.). Accordingly, the diesel line  124  may be in downstream communication with the separator  140  and specifically a bottoms line  146  of the separator. The separator may be operated at a top pressure of about 150 psig (1034 kPa) (gauge) to about 400 psig (2758 kPa) (gauge) and a bottom temperature of about 300° F. (149° C.) to about 650° F. (343° C.). 
     The resulting diesel blend has an initial boiling point temperature in a range between about 250° F. (121° C.) and about 300° F. (149° C.), typically between 260° F. (126° C.) and 290° F. (143° C.) and preferably between 270° F. (132° C.) and 280° F. (137° C.). The resulting diesel blend also has a T10 temperature in a range between about 360° F. (182° C.) and about 450° F. (232° C.), typically no less than about 380° F. (193° C.) and preferably no less than 400° F. (204° C.). The resulting diesel blend additionally has a T95 temperature in a range between about 600° F. (316° C.) and about 700° F. (371° C.) and preferably between about 625° F. (329° C.) and about 675° F. (357° C.). Lastly, the diesel blend may have a cetane rating between about 40 and about 60. The diesel blend may also have a density between about 51 lb/ft 3  (820 kg/m 3 ) and about 54 lb/ft 3  (870 kg/m 3 ). It is also contemplated that some of the kerosene stream may be blended into the diesel blend if necessary so as to meet an applicable density specification. 
     The unstabilized naphtha in the net overhead line  68  from the stripper  50  may be fed to a debutanizer column  80  in downstream communication with the overhead line  68 . In the debutanizer column  80 , the overhead stream from the stripper column  50  is separated into a net LPG stream in a net overhead line  82  and a light naphtha stream in a bottoms line  86 . The debutanizer column  140  is in downstream communication with the hydrocracking reactor  12  and the stripper column  50 . The debutanizer column fractionates the unstabilized naphtha to provide a net off-gas stream in line  84  and a net LPG stream comprising predominantly C 4 − hydrocarbons in line  82  and a light naphtha stream comprising predominantly C 5 + hydrocarbons in bottoms line  86  and boiling between about 70° F. (21° C.) and about 210° F. (99° C.) TBP. The debutanizer column may be operated at a top pressure of about 150 psig (1034 kPa) to about 400 psig (2758 kPa) (gauge) and a bottom temperature of about 300° F. (149° C.) to about 650° F. (343° C.). The pressure should be maintained as low as possible to maintain reboiler temperature as low as possible while still allowing complete condensation with typical cooling utilities without the need for refrigeration. In an aspect, a bottoms line  86  from the debutanizer column is in downstream communication with a net overhead line  144  of the separator  140 . The medium naphtha stream in the net overhead line  144  from the separator  140  may be blended with the light naphtha stream in bottoms line  86  to provide a blended gasoline stream boiling in the range of about 70° F. (21° C.) to about 300° F. (149° C.) TBP in line  146  that can be recovered. 
       FIG. 2  illustrates an alternate embodiment of  FIG. 1  which uses a single separator instead of a separator  140  and a debutanizer column  80  as in  FIG. 1 . Many of the elements in  FIG. 2  have the same configuration as in  FIG. 1  and bear the same respective 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 , the separator  140 ′ is in downstream communication with a net overhead line  68 ′ of the stripper column  50  and the net overhead  130  from the product fractionation column  90 . The net overhead stream in line  68 ′ from the stripper column  50  and a net heavy naphtha overhead stream in net overhead line  130  are both separated in the separator  140 ′. The separator  140 ′ separates a net off-gas stream in line  142 ′ and a condensed net LPG stream in line  144 ′ and a gasoline stream in line  150  boiling in the range of about 70° F. (21° C.) to about 300° F. (149° C.) TBP from a side outlet  150   a . In a bottoms line  146 ′ from the separator  140 ′, a heavy-heavy naphtha stream is produced which is excellent for blending with the diesel stream in line  124 . The heavy-heavy naphtha stream may have an initial boiling point temperature between about 250° F. (121° C.) and about 280° F. (137° C.). Accordingly, the diesel line  124  is in downstream communication with the separator  140 ′ and specifically a bottoms line  146 ′ of the separator. The separator may be operated at an overhead pressure of about 150 psig (1034 kPa) (gauge) to about 400 psig (2758 kPa) (gauge) and a bottom temperature of about 300° F. (149° C.) to about 650° F. (343° C.). 
     Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. It should be understood that the illustrated embodiments are exemplary only, and should not be taken as limiting the scope of the invention. 
     Without further elaboration, it is believed that one skilled in the art can, using the preceding description, utilize the present invention to its fullest extent. The preceding preferred specific embodiments are, therefore, to be construed as merely illustrative, and not limitative of the remainder of the disclosure in any way whatsoever. 
     In the foregoing, all temperatures are set forth in degrees Celsius and, all parts and percentages are by weight, unless otherwise indicated. Pressures are given at the vessel outlet and particularly at the vapor outlet in vessels with multiple outlets. 
     From the foregoing description, one skilled in the art can easily ascertain the essential characteristics of this invention and, without departing from the spirit and scope thereof, can make various changes and modifications of the invention to adapt it to various usages and conditions.