US2197007A - Conversion of hydrocarbons - Google Patents

Description

April 16, 1940.l A. E. PEw, JR

CONVERSION'- OF HYDROCARBONS Filed Nov. 20, 1936 Patented Apr. 16, 1940 PATENT OFFICE coNvEnSIoN oF HYDRocAnBoNs Arthur E. Pew, Jr., Bryn Mawr, Pa., assignor, by

mesne assignments, to Houdry Process Corporation, Wilmington, Del., a corporation of Dela- Ware Application November zo, 1930, serial No. 111,780

18 Claims.` (Cl. 196-48) The present invention relates to the art of treating or converting hydrocarbons and especially to Cil thev production from starting material containing higher boiling hydrocarbons of valuable, high anti-.knock lower boiling hydrocarbons of the benzine, naphtha or gasoline type. It is particularly concerned with the production of such lower boiling hydrocarbons from hydrocarbons which contain both dimcultly vaporizable materialvof the type found in heavy fuel oils or in crude petroleum distillation residues and easily vaporizable distillate materials'of. the type of gas oil yields qf good anti-knock motor fuels.

and the like. y Various systems for eiecting pyrolytic or thermal conversion of hydrocarbons into valuable 1 products of the gasoline or motor fuel type are known andseveral such systems which differ from one another in only minor respects are in common use. These systems are capable of handling fresh and/or partially converted clean dis,- tillate or easily vaporizable materials with reasonable facility to make therefrom acceptable When working on heavy charging stocks or material containing substantial amounts of difdcultly vaporizable hydrocarbons, however, these systems can produce good anti-knock motor fuels directly a from such Stocks only at vrelatively great sacrifice of yield with attendant high yields of coke and gas. The motor fuels so produced from the heavy charging stocks are often dark in color l and/or sour and are consequently relatively difllcult to refine. The relativelyhigh yields of coke require frequent shuttingv down of the system for the purpose of removing` accumulated coky deposits therefrom. In order to minimize coky deposits and te otherwise facilitate handling of` these heavy materials, refiners have heretofore resorted Atotwo or more cracking steps: rst, one or more viscosity breaking operations to form crackable gas oil and extremely heavy residuum, and, second, a cracking operation `to convert the gas oil so formed into` gasoline and further tarry bottoms.` 1

Another type of system involves the use of absorbent and/or adsorbent contact masses capable of promoting thedesired reactions and of retaining therein and thereon any reaction products of.

a gummy, gum forming, cokyI or coke forming nature so that the products passing vtherefrom are clean and-are comprised essentially of easily vaporizable materials. After Separation of the desired lowerboiling hydrocarbons from the products the remaining residue has the characteris- -tics and uses of clean distillates of the gas oil type,y The contact mass or catalyst gradually loses activity as the depositaccumulates and requires periodic renewal or regeneration to eiect removal of the deposit. Such systems usually -perform to best yadvantage in vapor phase on successive and distinct passes on fresh charge and segregated residues under increasingly severe reaction conditions and generally produce the best yield of lower boiling hydrocarbons during the rst pass, i. e.,l from fresh or original charge. They produce high yields of. good anti-knock lower boiling hydrocarbonswhich are relatively easily refined directly from dimcultly vaporizable charging stocks vcontaining substantial amounts of materials'which are resinous or coky in nature ory which tend to produce resinous or coky sub- L .stances without any preliminary cracking or viscosity breaking operationsas well as from easily vaporizable clean distillate stocks. In order to eifect vaporization of the high boiling portions of the residual charging stock without substantial pyrolytic cracking thereof and/or to maintain vapor phase conditions during the operation it is usually necessary to employ an inert diluent fluid which lowers the partial pressure of the charging stock. Such fluids increase to substan-L tial extent the'volume of material handled-by fractionating equipment and their us'e requiresv fractionating columns and auxiliary equipment which are extremely large and expensive to operate.

Onebbject of the present invention is advantageously to combine a catalytic system with a pyrolytic system, so that the advantagesv of each are Secured and disadvantages -minimized or eliminated. Another object is to effect economies of heat and of equipment. Other objects will be apparent from the detailed discussion which follows. l

A quick understanding of' theinvention may be had by referring to the illustrative embodiment thereof shown in the accompanying drawing.

The drawing shows a catalytic reaction zone indicated by reference character A and enclosed bya broken line and a thermalv or pyrolytic reaction zone B set off by a dot and'dash line. Reaction zone A' contains acatalytic system of any vknown orrdesiredl type providing one or more reaction vessels containing absorbent and/or adsorbent contact material capable of promoting transformation of higher boiling hydrocarbons into clean, easily vaporiaable products 1having or a plurality of pyrolytic conversion systems of any known or desired type.

Catalytic zone A and pyrolytic zone B are each connected to a fractionator forfresh charging stock such as fractionating column I and with a products fractionator such as fractionating column 2 to provide unitary apparatus, all elements of which function continuously, simultaneously and interdependently in producing good antiknock lower boiling motor fuels, such as gasoline, from charging materials containing both difficultly vaporizable and easily vaporizable hydrocarbons, as exemplied by whole petroleum crude oil,

'rectly into products fractionator 2.

topped crude and various blends of distillate and residual stocks which may be made or may occur in refinery practice. Fractionating column I receives fresh charge and divides it into one or more distillate fractions comprising essentially easily vaporizable hydrocarbons which provide charge to pyrolytic zone B and into a residual fraction .containing substantially all of the dimcultly vaporizable material in the charge, with or Without substantial amounts of lower boiling components, which is fed to catalytic zone A. Thus pyrolytic zone B handles only materials of the type which it is capable of converting to best advantage into easily relnable lower boiling hydrocarbons of high antilmock rating and which causes a minimum of shut-downs for removing accumulated deposits of coke and the. like, while the diflicultly vaporizable materials are transformed by the system capable of producing from them the maximum amount of products of highest quality and value, including sweet, high anti-knock lower boiling hydrocarbons and clean higher boiling hydrocarbons having distillate characteristicsy and uses. The lower boiling hydrocarbons made k irl-'both zones A and B are separated from higher what roughly separated condensateshaving differing boiling range characteristics, namely, in the order of their production, one or more liquid fractions comprising essentiallyclean higher boiling hydrocarbons, andv a liquid fraction comprising desirable lower boiling hydrocarbons, permissibly having therewith a small amount of higher boiling hydrocarbons, as Ifor example, of the light gas oil or heavy naphtha type.' After separation of fixed gases and any extraneous material such as Water therefrom thelatterfraction lis admitted in liquid phase to products fractionator 2 at or adjacent the top thereof to act as a refluxing agent therein and to, be separated into higher and lower boiling hydrocarbons with the material from the first mentioned zone. The above/procedure secures economies of heat and equipment in addition to the above indicated advantages of the combined pyrolytic and catalytic systems. Heat that is ordinarily lost Vto the proce byreturning to a fractionating column, as refl partof the condensed overheadfrom the column is, according to this invention, retained in the system and used to advantage in the procalamo? ess. Furthermore, products fractionator 2 and the heat exchanging means following it handle a minimum of material and thus provide for decreased rst investment and operating costs. v

.In the embodiment of the invention disclosed in the drawing, fresh hydrocarbon charge, for example, a whole crude, is heated to distillation temperature in heater 3 and is conducted through line 4 to fractionator I wherein it is divided into an overhead cut, two side stream distillate fractions anda residue which leave the column by lines 5, 6, 'I and 8, respectively. The overhead fraction'in line 5v contains lower boiling hydrocarbons which it is not necessary or desirable to convert. 'I'he side stream distillate fraction leaving column I by lines 6 and I are chargedpreferably separately but permissibly together to pyrolytic zone B and may be a naphtha fraction and a gas oil cut or relatively light and relatively heavy gas oil cuts. Pyrolytic zone B is shown as containing three pyrolytic conversion units, indicated by cracking furnaces 9, I0 and II, selectively connected to fractlonator I, so that any one or any combination of these units may effect the desired conversion of the fractionsin lines 6 and 'I. These pyrolytic conversion units are also selectively connected to line I2 and discharge reaction products into v,the latter which conducts them into fractionator 2, shown provided with an outlet I3 for partially converted higher boiling hydrocarbons or inconvertible cracked residuum such as tar andthe like, one or more side stream outlets such as lines 41, I4 and 48 for heavy naphtha, light gas oil and heavy gas oil fractions, respectively, and an overhead vapor line I5 for desired end point lower boiling hydrocarbons and fixed gases.

.The residue leaving fractionating column I by line 8 is charged to catalytic zone A.` This stock has had removed from it practicallyall ofthe material which it is possible to vaporize at the non-cracking or low cracking temperatures which usually exist in the furnace 3. Itis therefore necessary, in order to vproduce further cracking stock, which will be free ofy heavy or tarry constituents, from the heaviest portions of this residue, to subject it to a diierent set of condi`` tions than those existent in .furnace 3 and tower- I. If the residue is heated to a higher temperature than that to which the crude was heated in furnace 3, cracking ofthe heaviest material will take place withtthe production of low boilingv tcks including gasoline of an inferior quality.

is operation, however, would not produce sufcient'stock in condition to be properly cracked in the catalytic zone. Steam or other suitable the partial pressure effect produced, in order to vaporize the desiredstock without ,cracking the heavy ends of thefesidue in the process.

-As shown in the attached drawing, this stock is forced by means of pump I6 through the coil inert diluent fluid istherefore used, because of within the furnace n, wherein it is heated te substantially the desired final temperature and from l0 to 20% by weight o f steam is added by injection into thev coil through line l I, the amount of steam used at this point being dependent upon" the characteristics of the individual charge and upon the temperature to which it is desired to raise the charge in furnace I'I. The steam so added is 'preferably 'superheated steam atsub lstantially lthe same temperature as. the stock flowingthrough that portion of the coil into which the steam is injected. After the injection of the steam, the oil and steam are still further v 2,197,007 heated and passed to a vaporizer or tar separator I8, wherein vaporized material is separated from the tarry bottoms which are withdrawn by line I9. 'I'he mixed oil vapors and steam then pass through line 20 to one or more of the catalytic converters 2l selectively connected to line 20 and containing contact mass capable of promoting the desired transformation' of the vapors During the passage of vapors through line 20, additional steam, as up to 10%I by weight of the charge to zone A vis injected through 'line 42..' The steam so injected is at least at the same temperature as the mixed oil and steam in line 20, but is preferably at a slightly higher temprature. In no1'- mal operation 15% or more of steam is utilized which is added as preferred either by line 4I, or partly by line 4I and the remainder by line 42.

It is well known that when a mixture of iiuid and vapor is discharged into a separator and the vapor taken overhead, such vapor contains small particles of liquid in the form of a mist. If such vapor is thensubjected to a cracking reaction the small liquid particles in the vapor readily form coke during the cracking reaction. For this reason the steam is injected through line 42 to dry the vapors by furnishing suflicient heat and partial pressure effect to secure the vaporization of anyr liquid oil in the -form of mist remaining in the vapors.

The cracked vapors flow from the `catalytic chambers 2| through line 22 and are cooled in a succession of steps in heat exchangers 23 and 24,

- wherein a very rough fractionation takes place` wide range gas oil cuts of relatively heavy and relatively light nature being removed through lines 28 and 29, respectively, and a distillate containing all of the cracked gasoline and a portion of the heavy naphtha from the top of heat exchanger 24. Such fractionation must be resorted to due to the immense volume of vapors which it ls necessary to handle because of the addition of steam through lines 4I and 42. When 10% steam is added through line 4I and 5% additional steam injected through line 42 the volume ratio of steam to condensible oil vapors in line 22 is of the order of :1 while the presence of fixed or incondensible gases lfurther augments thisdrocarbon gases, such as those made in cracking and other renery operations.

flnery gases are used, even larger volumes of- When rethem are required than of steam to give .the

y desired partial pressure effect.

If ordinary fractionation in a distillation tower was employed it would require so large a tower and auxiliary condensing equipment as to make the process uneconomic from an investment standpoint and expensive tooperate. However, by employing the partial condensing heat exchangers 23 and 24 and the exchanger 25, which latter `is in some instances augmented by cooler 31, it is possible lto roughly fractionate into two gas oil cuts and acracked distillate. The cracked distillatev after separation from thewater. and fixed gas in separator 32, is removed through line 33 and forced by pump 34 to fractionating tower 2, wherein t is used as a reiiuxing liquid to supplant that ordinarily furnished by condensing the overhead vapor fraction `taken off through line I5. Infractionating towers following cracking units the reflux rate may vary from 3:1 to 8:1, depending upon the degree and accuracy of fractionation desired, and also upon the materials fed to the tower for fractionation. The ratios'herein stated are volume ratios; vreiiux to condensed overheadprod'uct. If suicient reyflux is not' available for fractionation in tower 2 in the material passing .to the tower through line 33, additional make-unmaterial may be withdrawn from the condensate produced in condenser 35, as from gas separator 36, and

passed back to the top of the tower 2.

According to the accompanying drawing, the

fresh charge is used as the heat exchange medium in the rough fractionation of the catalytic syntheticv crude. To effect this, fresh charge, supplied by line 26, prior to its admittance to heater 3, is forced by pump 21 through serially connected heat exchangers 25, 24 and 23 countercurrently to and in heat exchange relationwith the catalytic synthetic crude. By use of the valved by-pass lines around each of these exchangers the amount of heat exchange in each may be so regulated that a controlled and predetermined portion .of the catalytic synthetic crude is condensed Ifin each. In order to effect trolle'damounts of fresh'charge maybe passed,

by proper use of valved by-pass 44. When the bottoms or residual fraction of the fresh charge is unusually large and/or very large amounts of steam are required in catalytic zone A, the cooling Acapacity of the lfresh charge may be augmented by an auxiliary cooler, such as cooler 31, provided with valved by-pass'38 therearound.

Clean higher boiling hydrocarbon condensate .producedby partial condensation of synthetic crude issuing from one of the reaction zones, as for example and by preference thehigher boiling condensate derived from catalytic synthetic crude leaving heat exchangers 23 and 24, by lines 28 and 2 9, after being stripped of lowerv boiling hydrocarbons, or not, as desired, may be charged to ,pyrolytic zone'B for conversion separately or suitably mixed with distillates leavingcolumn I by li'nes 6 and 1, these "condensates being conducted through lines 39 and 4|)1connected'to strippers 30. and 3I and to zone B. When a very high degree of conversion is desired, one or more cuts of material having heavy naphtha and/or gasoil characteristics may be taken from fractionator 2 and reconverted. For realization of the best yields of highest quality products therefrom it is preferable ,that such fractions and particularly the heavy naphtha' and heavy gas oil fractions be converted separately as in separate and distinct conversion systems or units, as for example in zone B, maintained under reaction conditions best suited for each iparticuin the process. jIhe drawing shows illustrative connections for conducting tovpyrolytic zone B the light gas oil fraction issuing from fraction ator 2 by line I4. Line "45tpermits this fractionv to be charged to pyrolytic zone B either separately or with any other stream of .material entering zone B. Pyrolytic zone B is adapted for any desired type of operation. `For exam'- ple, each fraction to be converted in this zoneI may be treated separately in a separate conversion system or,v unit, or one or more streams` of charging material to this zone may comprise a desired blend of selected materials and may be, for instance, a-desired blend or blends of any desired number of virgin or unconverteddistillatesissuing from column I or any desired blend of unconverted and partially converted or .transformed distillate materials, as for' example, a blend of virgin gas oil with a gas oil fraction produced from partial condensation of one of the synthetic -crudes and/or a. gas oil cut such as that leaving fractionator 2 by line I4. Furthermore, streams of charging material to zone B may be shifted from any unit to any other to permit Acleaning of any unit and toV securev continuous operation without requiring cessation of operation of the combined pyrolytic and catalyticA zones for cleaning out pyrolytic conversion units.

The conversion unit or units employed in pyrolytic zone B may be of any known or desired type for effecting conversion of higher boiling hydrocarbons into lower boiling hydrocarbons in the vapor phase, liquid phase or mixed phase and may involve :internal recycling of partially converted material on may be utilized in straight pass operations. Suitable processes and equipment includes processes and apparatus known as the Cross, Dubbs, tube and tank, De Florez, true vapor phase, gyro, and Holmes- Manley systems,

vary with the characteristics of the charge and with the type of pyrolyticsystem use`d. Suitable temperatures usually lie within the range of 750 F. to 1200o F., while the pressures mayv range from atmospheric or slightly below to 2500 lbs. per sq. in. or higher.

The contact mass employed in catalytic zone yA may be any -absorbent and/or adsorbent material capable of aiding the desired reactions. Good results are usually obtained with contact masses comprising or containing materials of siliceous nature or origin, derived from naturally occurring or artificially prepared substances, with or without the inclusion or addition of desired amounts of active or modifying ingredients.'

Suitable contact masses include blends of silica and one or more metal oxides capable of assisting in the transformation reactions and/or of promoting regeneration. 'I he blend may be derived from naturally occurring materials or from precipitated or non-precipitated gels comprising or containing mixtures or .compounds of silicia and`one or more metal oxides. Excellent results vhave been realized with contact masses containing blends of silica and almina of artificial origin or derivedv from naturally occurring silicates and hydrosilicatesv of alumina, including activated.

May 4, 1937) and Serial No. 35,101, filed August 7, 1935 (Patent No. 2,078,951, granted May 4, 1937). .In order to facilitate regeneration the contact masses may be in the form of fragments or molded pieces, as indicated in the above mentined applications.

'Ihe catalytic system in zone A may be 'of any known or desired type employing one lor more converters of any known or desired construction, in which, for example, the contact mass may bearranged in tubes, as annuli, in layers, or as a single body. The converters may be arranged and adapted for use alternately in transformation of the chargeand in regeneration of the contact mass in place-jor, though less advantageously for periodic discharge of the contaminated Contact mass and recharging of fresh or` regenerated catalyst. The heat necessary for vaporizing the charge and raising the same to reaction temperature may be added wholly or partially in an auxiliary heater, such as heaterJ'I, which 'may` 'of James W. Harrison and Thomas B. Prickett,

issued February 25, 1936. I'he best' operating conditions forcatalytic zone A will vary with the source'and type of both charging stock and contact mass. Suitable temperatures and pressures for eicient transformation of most residual 'i stocks utilizing catalysts comprising essentially blends of silica and alumina usually lie within the ranges of 750-F. to 925 F. and atmospheric pressure to about 7.5#/sq. in., respectively.

The following example is given as typical tol further illustrate the invention.

An East Texas Crude was divided in an initial 'fractionator such as fractionator I into (l) an overhead cut vcontaininga straight run Igasoline of about 300 F. E. P. representing about 15% of the crude; (2) a heavy naphtha fraction boiling substantially-completely in the range of 250 F. to 420 F. representing about 22% of the original charge; (3) a clean, distillate gas oil cut representing about 26% of the crude-and boiling substantially completely withinthe rangle of v400 F. to 700 F.; and` (4) a high boiling residue or bottoms cut containing substantially all diicultly vaporizable material inthe charge and representing approximately 37% of the fresh crude. The heavy naphtha cut and the gas oil fraction were converted separately in single pass operations in a pyrolytic reaction zone, as in units 9 and I0 in zone B, thenaphtha. being subjected to a tern--J perature of the order of 900 to 930 F. and a pressure of approximately 1375 lbs. per sq. in. for approximately seconds to effect reforming or improvement in the antiknock ratin'g thereof, and the gas oil being' subjected to the action of temperature and pressure-of about 890. F. and 1750 lbs/sq. in. respectively, for about 3 minutes to produce good antiknock lower boiling hydrocarbons. Coincidentally with the conversion of the naphtha and'gas oil fractions the residue was.

.transformed in a catalytic zone such as zone. A.

Before admittance to the catalyticzone the residue admixed with about 10% steam by weight thereof was heated to a .temperatureof the order of 890 F. as inhe'ater I1 to eiect vaporization of a substantial proportion of it. llnyaporized material to theextent ofhabout 6% of the original crude was removed from fthe vapors in a suitable separator such as separator I8 as a heavy tar' leaving the latter by line I9 and having a specific .gravity of about 1. -The vapors issuingfrom separator i8 by line 20 under a pressure of the to, as by line 42, of superheated ,steam to the amount of about 5% by weight of the residue, were charged to a converter, such as one'of the converters` 2l, containing a catalyst comprising essentially a blend of silica and alumina in the weight ratio of about 31/2 to 1 and maintained at a temperature of about 860 F. vThe rate of feed of detarred vapors to the converters was of the order of 3:4 (3 volumes of condensed vapors per hour to 4 volumes of contact mass). Reaction products from both zones were fractionated in a single products fractionating column such as column 2, those from the pyrolytic zone being discharged directly into the column at a-point adjacent its bottom as through line I2. The catalytic reaction products were subjected to a series of controlled cooling steps by passing them through a series of heat exchangers such as exchangers 23, 24 and 25 in heat exchange relation with the relatively cold fresh crude to produce, as condensate, two roughly separated higher boiling hydrocarbon fractions suitable for use as domestic or Diesel fuel oils or as cracking stock, namely, a relatively heavy gas oil, condensed in partial condensing heat exchanger 23 and withdrawn therefrom by line 28,

a relatively'light gas oil fraction condensed in- -partial condensing heat exchanger 24 and withdrawn byline 29 and a liquid fraction comprising essentially lower boiling hydrocarbons of the motor fuel type. produced in heat exchanger 25. p -After being stripped of entrained lower boiling hydrocarbons in strippers 30 and 3| the gas oil fractions had boiling ranges of the order of 600 to 750 F., and 450 to 650 F. The light fraction' was conducted byline and 'added to the gas oildistillate cut in line 1 passing to pyrolytic still I0. The heavy distillate fraction was conducted by line 39 for conversion separately in cracking unit II at a temperature of about 880 F. and pressure of about 1750#/sq. in. for about 3 minutes. about 85% hydrocarbons boiling below 400 F. and about 15% light gas oil, after removal of fixed gases and condensed water therefrom, in separator 32, was fed', in liquid phase, by line 33 into the product fractionator at a point adjacent the top thereof wherein-it acted as `reflux and was divided into lower boiling and higher rboiling hydrocarbons along with the pyrolyticrea'ction products. From the top of the products fractionator there was withdrawn, as by line l5, a vapor fraction comprising a blend of catalytically transformed and pyrolytically converted end point motor fuel and fixed gases made inthe pyrolytic system.n A clean light gas oil fraction was withdrawn from tower 2 by line I4, and a portion was removed for use as fuel oil while the remainder was sent by line to be added to the heavy condensate fraction in 'line 39 passing to cracking unit II.v lA residual fuel Acomprising a heavy cracked tar was vented from 'thelbottom of the tower by line I3. The overhead fraction from products lfractionator 2 when condensedA The remaining fraction ,comprising bodying the advantages of both the pyrolytic and catalytic systemswhileobviating the disadvantages of each. The difcultly vaporizable or heavy constituents in the charging stock are treated in a manner to realize the greatest yields of high quality gasoline therefrom with an attendant minimum production of coky products having little or no value, while the easily vaporizable materials are handled to. advantage. In addition to theabove, substantial economies and great flexibility of operation are secured.

I claim as my invention:

1. In the production of valuable motor fuels,-

the process comprising dividing original charging stock containing higher boiling hydrocarbons into distillate and residual fractions, separately convverting each .fraction into motor fuel of thegas'- oline type in separate conversion zones maintained under conversion conditions,l effecting stepwise cooling of products issuing from one of said conversion zones to produce a plurality of formed from saiddistillate and residual fractions.

2. In the production of lower boiling hydro-.

carbons, the process comprising separating into a distillate fraction and a residual fraction a charging stock containingboth'difcultly vaporizablef and easily'vaporizable hydrocarbons, ef-

fecting conversion of said distillate fraction into desired lower boiling Hydrocarbons in a pyrolytic conversion zone maintained under pyrolytic con'- version conditions, effecting conversion of said lresidual fraction into valuable lower boiling hydrocarbons in' a catalytic conversion zone containing an adsorptive contact mass capable of promoting cracking reactions and maintained under cracking conditions, subjecting products of conversion issuing from one of said zones to stepwise cooling to yield a plurality of condensates of differing boiling ranges including a lower boiling condensate consisting essentially of desired lower boiling hydrocarbons, admitting the remainder of the conversion products in vapor phase to a fractionating zone, withdrawing a motor fuel fraction of desired end point from said fractionating zone, and utilizing said lower boiling condensate as reflux in said fractionating zone, thereby si- Ymultaneously .to assist in heat removal from and control of. the latter and to produce a nal fractionated motor fuel comprising a blend of pyrolytic and catalytic end point.

3.-In the production of valuable lower boiling hydrocarbons ofthe motor fuel type the process of dividing a charging material containing both reaction products of desired i difcultly vaporizable and easily vaporizable hy-k y drocarbons into at least one distillate fraction .comprising essentially easily vaporizable hydro.-

carbons anda residual fraction containing substantially all diilicultly vaporizable material in the charge, feeding the distillate fraction to a pyrolytic conversion zone maintained under suitable conditions for effecting conversion thereof into lower boiling hydrocarbons, removing reaction products from said conversion zone, feeding from the other of said zones into a plurality of fractions having relatively different boiling ranges, the lowest boiling rang fraction comprising essentially lower boiling hydrocarbons of the motor fuel type, effecting substantial condensation of said lowest boiling range fraction, separatinggthe resultant condensate from uncon- -densed material, and admitting said condensate as liquid to said fractionating zone to serve as reflux therein and to be fractionated along with the reaction products from the said pyrolytic conversion zone, thereby to minimize or avoid use of condensed overhead fromsaid fractionating zone as reflux and to provide a blend of catalytically and pyrolytically produced motor fuel.

4. In producing lower boiling hydrocarbons of the'motor fuel type, the process comprising dividing charging material containing both easily vaporizable and dilcultly vaporizable hydrocarbons into a distillate fraction vand a residual fraction, eecting pyrolytic conversion of said distillate fraction under pyrolytic decomposition conditions into motor fuel products, vaporizing said residual fraction with the aid of a diluent fluid, subjecting vapors so produced to catalytic cracking in a reaction zone containing porous adsprptive cracking catalyst maintainedunder vapor phase cracking conditions, subjecting pyrolytic reaction products to fractionation to yield a motor fuel fraction of the desired endpoint, dividing' catalytic reaction products by successive stages of partial condensation into at least two condensates of differing boiling ranges, the lower boiling 1condensate comprising Y essentially lower boiling hydrocarbons having the desiredmotor fuel boiling range, separating said diluent fluid from said lower boiling condensate, and utilizing the latter as reflux said fractionating step, thereby to assist in the fractionation of said pyrolyticproducts while simultaneously effecting fractionation ofcatalytically produced motor fuel to yield a final motor fuel of the desired boiling range comprising a blend of pyrolytic and catalytic products. y

5. In the production of lower boiling hydrocarbons, the process comprising dividing a charging stock containing both diflicultly vaporizable and easily vaporizable higher boiling hydrocarbons into a distillate fraction and a residual fraction, effecting pyrolytic conversion of said distillate fraction under pyrolytic cracking conditions into motor fuel of the gasoline type, effecting catavlytic? cracking of vsaid residual fraction with the aid of an adsorptive contact mass capable of promoting formation of high anti-knock` motor fuels and maintained under cracking conditions, fractionating pyrolytic reaction products to yield a motor` fuel fraction of controlled "end-pointdividing catalytic reaction products into a higher boiling condensate and a lower boiling condensate, said lower boiling condensate comprising catalytically cracked motor fuel of the gasoline type, utilizing sa lower boiling condensate as reflux in said fr onating stepl tel assist in re- .moval of heat from pyrolytic reaction products and to assist in rectification of the latter while simultaneously rectifying catalytic reaction products and yielding a motor fuel of the desiredv end point comprising a blend of catalytically and pyrolytically cracked products, and effecting py'- rolytic conversion of said higher boiling ccnden? sate.

6. In.the production of valuable motor fuels, the process steps comprising dividing into a distillate fraction and a residual fraction a charging stock containing both difficultly vaporizable and easily vaporizable higher boiling hydrocarbons, effecting yvapor phase conversion of said a fractionating zone, withdrawing from the latter a motor fuel fraction of the desired boiling range, and utilizing said lower boiling condensate as reflux in said fractionating yzone, thereby to assistinthe control of said fractionation and to yield a flnal motor fuel product comprising a blend of pyrolytically and catalytically converted products.

7. In the production of valuable lower boiling hydrocarbons, the process of dividing a charging stock containing both easily vaporizable and difficultly vaporizable hydrocarbons into a distillate fraction and a residual fraction, effecting pyrolytic conversion of said distillate fraction, 'vaporizing a# substantial portion of said residual fraction, transforming such vapors into valuable lower boiling .hydrocarbons and clean higher boiling distillate with the aid of an adsorptive contact mass comprising essentially a blend of silica and Ialumina, passing reaction products of said pyrolytic conversion, to a fractionating zone, dl-

viding the reaction products from `the other of said fractions intera gas oil fraction, and a lower boiling fraction comprising essentially` desired lower lboiling hydrocarbons, admitting at least a portion of said lower-boiling fraction as liquid reflux to said fractionating f-zone, withdrawing a gas oil fraction from said fractionating zone, effecting pyrolytic conversion of a portion of said gas oil fractions, and commingling the reaction products therefrom with the reaction products from said distillate fraction prior to thel fractionation step. f

8. In the production of valuable lower boiling hydrocarbons the process of dividing a charging material containing both dii'licultly vaporizable,

and easily vaporizable hydrocarbons into at least two clean distillate fractions of differing boiling range, one' relatively lower boiling and the other relatively higher boiling andy a residual fraction containing substantially all diflicultly Vaporizable material in the charge, feeding the distillate fractions separately to a conversion zone maintained under suitable conditions for effecting separate pyrolytic conversion of each into valuable lower boiling hydrocarbons of the motor fuel type, removing reaction products from said 'conversion zone, feeding said residual fraction te la reaction zone containing an 'adsorbent contact masscapable of promoting transformation thereofl into lower boiling hydrocarbons and clean higher boiling hydrocarbons having distillate characteristics and maintained under transformation conditions, removing reaction products from said. second reaction zone, admitting the reaction products from the mst-mentioned of said zones substantially in vapor phase to a fractionating zone adapted to separate lower boiling hydrocarbons from higher boiling hydrocarbons, cooling the reaction products from said second reaction zone in a series of steps to provide from said products a plurality of clean condensates having relatively different boiling ranges, the lowest boiling condensate comprising essentially lower boiling hydrocarbons, separating each condensate fromvv uncondensed material, admitting said lowest boiling condensate as liquid to said fractionating zone to serve'as reflux therein and to be fractionated along with the reaction products fromthe first mentioned one of said zones, feeding higher boiling condensate producedfrom said stepwise cooling of reaction products to said pyrolytic zone to be separately converted therein, and commingling reaction .products from said pyrolytic zone prior to fractionation thereof.

9. In the production of valuable lower boiling hydrocarbons of the motor fuel type from charging material containing both easilyV vaporizable,

and difiicultly vaporizable hydrocarbons, the process of dividing said charge into a plurality of clean distillate fractions and a residual fraction, one of said distillate fractions having the boiling range characteristics of gas oil, effecting separate conversion of said distillates into valuable lower boiling hydrocarbons of the motor fuel type in a reaction zone maintained under pyrolytic conversion conditions, vaporizing a substantial portion of said residual fraction with the aid of a diluent fluid, transforming such vaporsv into valuable lower boiling hydrocarbons and clean higher boiling hydrocarbonsy having distillate characteristicsin a catalyticzone containing an adsorbent contact mass capable of promoting the desired transformation, withdrawing reaction products from each o f s aid zones, admitting reaction products from said pyrolytic zone substantially in vapor phase to a fractionating zone adapted to lseparate desired lower boiling hydrocarbons from'higher boiling hydrocarbons, dividing reaction products from said catalytic zone into a plurality of condensate fractions, one of said fractions comprising essentially desired lower boiling hydrocarbons, another of said fractions being a gas oil removing said diluent fluid from said lower` boiling condensate fraction feeding said lower boiling condensate to said fractionating zone to act as reux therein and to be fractionated with the reaction products from said one of said zones, withdrawing gas oil cut, and a residue,- feeding said heavy naphtha cut and said gas oil cut to 'a pyrolytic reaction zone to be separately converted therein,

eifecting vaporization of said residue with the aid of an inert diluent iiuid, charging the vapors to a catalytic transformation system containing an adsorbent contact mass capable of promoting transformation thereof into lower boiling hydrocarbons of the motor fuel type andmaintained under vapor phase transformation conditions', removing reaction products from each of said zones, admitting pyrolytic reaction products in substantially vapor phase'to a fractionating zone, dividing catalytic reaction products into at least three condensates having relativelydifferent boiling ranges, two of said condensates being relatively heavy and relatively light gasoils, the other containing substantially all the desired catalytlcally'ltransformed motor fuel, separating said inert diluent iiuid from said last named cdndensate, admitting the latter as liquid, to said fractionating zone to serve as reflux therein, withdrawing a desired end point motor fueland a light gas oil fraction from said fractionating zone, commingling said light gas oil cut and said relatively heavy gas oil condensate, separately converting the resulting mix, ture in said pyrolytic zone, and addingv said relatively light gas oil condensate to said fresh gas oil cut prior to conversion of the latter. n

11. In apparatus for producing lower boiling hydrocarbons from charging material containing both easily vaporizable and difiicultly vaporizable higher boiling hydrocarbons, in combination, a heater for fresh' charge, a fractionating column connected to said heater adapted to effect separation of the charge into a distillate fraction and a residual fraction, a catalytic transformation system connected to said column adapted lto receive said residual fraction and to transform the same into lower boiling hydrocarbons and clean higher boiling. `hydrocarbons 1 having distillate characteristics, apyrolytic conversion system also consystems for receiving reaction products therefrom adapted to effect condensation of said reaction products in a succession of controlled steps. thereby to produce a plurality of condensates having differing boiling ranges, means for separating said condensates from uncondensed material and means for conducting the lowest boiling of said condensates from said separating means as liquid to theupper portion of said second fractionating column to serve as reflux therein.

12. In apparatus for producing lower boiling hydrocarbons from charging material containing both easily vaporizable and difiicultly vaporizable higher boiling hydrocarbons, in combination, a

' heater for fresh charge, aA fractionating column connected to said heater adapted to receive fresh chargeand to effect separation of the same into a distillate fraction and Aa residual fraction, a catalytic transformation system connected` to said column adaptedto receivejsaid residual fraction and to transform the same intol lower boiling hydrocarbons and clean higher boiling hydrocarbons having vdistillate characteristics, a pyrolytic conversion system also connected .to said column adapted to receive said distillate fraction and to convert the same into lower boiling hydrocarbons, la second fractionating columnA adapted to separate lower boiling hydrocarbons from higher boiling hydrocarbons, a vapor connection from said pyrolytic system to said last named fractionating column forconducting pyrolytic reaction products into the latter, means including a plurality of serially connected heat exchange means connected to said catalytic system for receiving reaction products therefrom adapted to effect condensation of said reaction products in a succession of controlled steps thereby to produce at least one higher boiling condensate of the gas oil type and a lower `boiling condensate comprising essentially desired lower boilingr hydrocarbons, and means including a conduit connection for lconducting said lower boiling condensate from said first named means to the upper portion of said second fractionating column to serve as reflux therein.

13. In apparatus for producing lower boiling hydrocarbons from charging material containing both easily vaporizable and diicultly vaporizable higher boiling hydrocarbons, in combination, a

, heater for fresh charge, a fractionating column connected to said heater adapted to eiect separation of the charge into a distillate fraction and a residual fraction, a catalytic transformation system connected to said column adapted to receive said residual fraction and to transform the same into lower boiling hydrocarbons and clean higher boiling hydrocarbons having distillate character- 1istics, a pyrolytic conversion system also connected to said column adapted to receivesaid distillate fraction and to convert the same into lower boiling hydrocarbons, a second fractionating column adapted to separate desired lower boiling hydrocarbons from higher boiling hydrocarbons, a vapor connection from one of said systems to said last named fractionating column for conducting reaction products into the latter, means including a plurality of serially connected heat exchange'means connected to the other of said systems for receiving reaction products therefrom adapted to effect condensation of said reaction products in a succession of controlled steps thereby to produce a higher boiling condensate of the gas oil type and a lower boiling condensate comprising chiey gasoline, means for separating said lower boiling condensate from uncondensed material, a connection for conducting said higher boiling condensate from said Afirst named means to said pyrolytic system, and means'includinga line for conducting said lower boiling condensate from said separating means to the upper'portion of said second fractionating column to serve as reflux therein.'

14. In apparatus for producing lower )boiling hydrocarbons from charging material containing both easily vaporizable and difllcultly vaporizable higher boiling hydrocarbons, in combination, a heater lforfresh charge, a fractionating column connected to said heater adapted to effect separation of the charge into a distillate 'fraction and a residual fraction, a catalytic transformation system connected to said column adapted to receive said residuall fraction and to trans'- form the same into lower boiling hydrocarbons and clean higher boiling hydrocarbons having distillate characteristics, a'pyrolytic conversion system also connected to said column adapted to receive said distillatefraction and to convert theL same into lower boiling hydrocarbons, a second fractionating column adapted to separate desired lower boiling hydrocarbons from higher boiling hydrocarbons, a vapor connection from one of said systemsto said last named fractionating column-for conducting reaction products into the latter, means including a plurality of serially connected heat exchange means connected tothe other of saidsystems for receiving reaction products therefrom adapted to effect condensation of said reaction products in a succession of controlled-steps thereby to produce at least one higher boiling condensate-of the gas oil type and a lower boiling condensate, means for separating said lower boiling condensate from un'con\ densed material, means including a conduit con,

nection for conducting separated condensate froma said separating means to the upper portion of said second fractionating column to serve as reux therein, an outlet connection on said second fractionating column for withdrawing therefrom a vclean higher boiling fraction,- and means including conduits for selectively conduct-` ing said highernboiling fraction and'said higher boiling condensate from said outlet and said heat exchange means to said pyrolytic system.

15. In apparatus for producing lower boiling hydrocarbons lfrom charging material containing both easily vaporizable and diiiicultly vaporizable hydrocarbons, in combination, a heater for fresh charge, a fractionating column connected to said heater adapted to effect-separation of the charge into a distillate fraction and a residual fraction, a heater for receiving and vaporizingsaid re- LsiduaLractiOn, means for adding inert diluent fluid to said fraction to assist in said vaporiza.-

tion, a convertercontaining an adsorbent contact mass capable of promoting transformation of said vaporized residue into lower boiling hydrocarbons, means for'conducting vapors from said heater to said converter,v a plurality of serially connectedvheat exchange 'means connected to said converter adapted to 'receive reaction products therefromand to produce a higher boiling condensate of the gas .oil type and a lower boiling condensate, means` associated with said heat exchange means for separating said inertdiluent fluid from said lowerboiling condensate, a pyrolytic conversion system connected to said fractionating column adapted to receive said distillate fraction and to convert the samevinto valuable lower boiling hydrocarbons, a second fractionating column, a vapor connection between said pyrolytic system land said second column, and a line for conducting saidlower boiling condensate from said separating means as liquid and freed of inert diluent to said second fractionating column to serve as reflux therein.

16. In apparatus for producing lower boilingI hydrocarbons from charging material containing both easily vaporizable and diiicultly vaporizable hydrocarbons, in combination, a heater for fresh charge, a fractionating column connected to said heater adapted to eect separation of the'charge i into a distillate fraction and la residual fraction,

a heater for receiving and vaporizing said residual fraction, means for adding steam to said fraction to assist insaid vaporization, means connected to said second named heaterl for separating and removing unvaporized residue from vapors, a catalytic converter, a line 'for conducting f -said vapors from said separating means to said converter,'means in said-line for adding additional steam to said vapors, a plurality of serially connected heat exchange means connected to said converter adapted l'to receive vreaction products therefrom to produce a plurality of roughly fractionated condensates, means connected to the last of said heat exchange means for ,separating and removing condensed steam and uncondensible vgases from the lowest boiling condensate. a pyrolytic conversion system connected to said fractionating column adapted to receive said distillate fraction and to convert the same into valuable lower boiling hydrocarbons, a second fractionating column, a vapor connection between said pyrolytic system and said second column, and a line for conducting said lowest boiling condensate from .said separating means as liquid and freed of condensed steam and gases to said second fractionatlng column to `serve as reflux therein.

17. In apparatus for producing lower boiling hydrocarbons from charging material containing both easily vaporizable and diilicultly vaporizable hydrocarbons, in combination, a heater for fresh charge, a fractionating column connected to said heater adapted to effect separation of the charge -into a distillate fraction and a residual fraction,

a heater for receiving and vaporizing said residual fraction, means for adding inert diluent fluid to said fraction to assist in said vaporization, a converter containing an adsorbent contact mass capable of promoting transformation of said vaporized residue into lower boiling hydrocarbons, means for conducting said vapors to said converter, a plurality of serially` connected heat exchange means connected to said converter adapted to receive reaction products therefrom to produce .a plurality of roughly fractionated condensates, steam stripping means connected with certain of said heat exchangers for stripping roughly fractionated condensate of entrained lower boiling hydrocarbons, means for separating condensed steam and xed gases from the lowest boiling condensate, a pyrolytic conversion system connected to said fractionating column adapted to receive said distillate fraction and to convert the same into valuable lower y boiling hydrocarbons, a conduit connection for conducting stripped condensate from said steam stripping means to said pyrolytic conversion system, a second fractionating column, a vapor connection between saldvpyrolytic system and said second column, and a line for conducting said lowest boiling condensate as liquid and freed both easily vaporizable and difcultly vaporizable higher boiling hydrocarbons, in combination, a

heater for fresh charge, a fractionating column connected to said heater adapted to effect separation of the charge into a plurality of distillate fractions and a residual fraction, a catalytic transformation system connected to said column adapted to receive said residual fraction and to transform the same into lower boiling hydro- Carbons and clean higher boiling hydrocarbons having distillate characteristics, a plurality of pyrolytic systems connected to said column so as selectively to lreceive said distillates for converting the same into lower boiling hydrocarbons of the motor fuel type, a second fractionating column, lines for selectively connecting said pyrolytic systems and said second column, means including a. plurality of serially connected heat exchange means connected to said catalytic system for receiving reaction products therefrom adapted to effect condensation of said products in a succession of controlled steps thereby to produce at least one higher boiling condensate comprising essentiallyclean hydrocarbons of the gas oil type and a lower boiling condensate comprising essentially desired lower boiling hydrocarbons, means for removing said condensates from uncondensed material, a line for conducting said lower boiling condensate to said fractionating column and introducing it into the upper portion thereof to serve as reiiux therein, a line for withdrawing from said second column a higher boiling fraction comprising clean gas oil, a connection for conducting said higher lboiling condensate ,to one of said pyrolyticsystems, and means for selectively conducting said higherl boiling fraction to one of said pyrolytic systems and said last named connection.

ARTHUR E. PEW, JR.

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