US2128898A - Conversion of hydrocarbon oils - Google Patents

Description

Sept. 6, 1938, c. H. ANGELL 2,128,898

' CONVERSION OF HYDROCARBON OILS FiledOct. 50, 1957 DISTILLING AND FRACTIONATING COLUMN ABSORBER HEAT 96 EXCHANGER FURNACE CO OLER llO Ill RACTIQNATOR I VAPORIZING AND SEPARATING CHAMBER FURNACE 4 RECEIVE HE AT EX INVENTOR CHARLES H. ANGE LL ATTORNEY Patented Sept. 6, 1938 L UNITED STATES CONVERSION OF HYDROCARBON OILS Charles H. Angell, Chicago, Ill., assignorto Universal Oil Products Company, Chicago, 111., a corporation of Delaware Application October 30, 1937, Serial No.,171,871 13 Claims. '(01. 196-9) This is a. continuation-in-part of two of my co-pending applications, Serial No. 661,242, filed March 17, 1933, and Serial No. 43,299. filed October 3, 1935.

The invention particularly relates to an improved process for the fractional distillation of hydrocarbon oils of relatively wide boiling range accompanied by the pyrolytic conversion of selected relatively high-boiling fractions of the charging stock together with a selected portion or all of the intermediate liquid conversion products of the cracking operations and accompanied by the reforming of all or selected high-boiling fractions of the gasoline components of the charging stock together, when desired, with se-. lected relatively low-boiling intermediate liquid conversion products of the process.

The term reforming as herein used is intended to designate that type of cracking operation wherein light distillate, such as gasoline or gasoline fractions or distillates, such as naphtha, for example, which contain a substantial quantity of. fractions boiling within the range of gasoline, are treated under conditions of high cracking temtrolled conversion time, regulated to effect a material improvement in the antiknock value of said gasoline fractions and simultaneously convert any higher boiling fractions of the distillate supplied 30 to the reforming step into substantial additional yields of good antiknock gasoline.

As a feature of the invention, selected highboiling fractions of the normally gaseous products of the process, which selected fractions consist principally of gases-containing'more than 2- carbon atoms to the molecule and including substantial quantities of readily polymerizable oleflnic gases, such as propene and butenes, are separated from the lower boiling gases by absorption 40 in all or a portion of the distillate .to be subjected v to reforming and the resulting enriched absorber oil,,containing said high-boiling gases, is supplied directly to the heating coil of the reforming step of the system wherein theabsorbed gases are subjected to treatment under the conditions maintainedin thisheating coil and'inthe presence of l the normally liquid hydrocarbons undergoing re- "forming therein and the products ofv the reforming operation. This feature of the process results 50 m amaterial improvement in the antiknock'value and/or yield ofthe gasolifnepr'oduct recovered "from the reforming stage 'of the process. This improved result may be due to polymerization-of theolefinic gases supplied-to the reforming coil *65*cir*to some interaction between the gases or perature, superatmospheric pressure and con-,

products resulting from their treatment. in the reforming coil with the distillate supplied to this zone and/or products resulting from thereforming treatment to which the distillate is subjected, or it may be due to a combination of both types of reaction. No experimental evidence sufliciently conclusive to form the basis for a scientific explanation of the type of reaction involved is yet available, but the lack of such scientific explanation does not detract from the practical value of this feature of the invention.

Another feature of the invention resides in the provision for controlling the time factor in the reforming step of the process by cooling the heated products discharged from the reforming coil by their indirect heat exchange with hydrocarbon oil charging stock for the process, whereby to supply the latter with at least a substantial portion of the heat required for its fractional distillation.

One specific embodiment of the process of the 2 invention comprises heating a hydrocarbon oil of relatively wide boiling range, such as crude petroleum, for example, to distillation temperature and separating the heated charging stock by fractional distillation into selected relatively lowboiling and higher boiling components, cracking resultant selected high-boiling components of the charging stock at elevated temperature and superatmospheric pressure, simultaneously reforming selected relatively low-boiling components of the charging stock resulting from said fractional distillation thereof and containing a substantial quantity of gasoline fractions of inferior antiknock value, effecting said reforming under conversion conditions of cracking temperature and superatmospheric pressure controlled independently of the cracking conditio'ns to which said high-boiling components of the charging stock are subjected, passing the highly'heated products of the reforming step in indirect heat exchange 40 with said chargingstock, whereby to cooljsaid products sufliciently to prevent any substantial further cracking thereof and whereby to supply heat to the charging stock for said fractional distillation thereof, separating the products of the. cracking step and the partially cooled products of the reforming step'into vaporous and nonevaporous components, fractionating the vapors to form a light reflux condensate and a heavy reflux condensa'te, returningsaid heavy reflux condensate to furthercrackin'g in the first mentioned cracking step,--returning said light reflux: condensate toi'further crackingiin the reforming step, sub- 1 .jecting fractionatedvapors ofthe desired endboilingpoint, which consist principally of good-'55 anti-knock gasoline and normally gaseous products, to condensation, stabilizing the resulting distillate to reduce its vapor pressure by liberating dissolved normally gaseous products therefrom, subjecting the resulting liberated gases, together with normally gaseous products previously separated from the distillate following said condensation step, to absorption by contacting the same with at least a portion of the oil subsequently supplied, as previously described, to the reforming step, thereby separating desirable highboiling components, including a substantial quantity of readily polymerizable oleflns, from the lower boiling components of said gases by absorption of the former and supplying the resulting enriched absorber oil, containing said desirable high-boiling components of the gases. to the aforementioned reforming step.

It will be apparent from the foregoing specific embodiment of the process that the invention does not reside in any single step or feature thereof but in the cooperative and interdependent combination of features provided. Many of the individual features of the process are disclosed in my two co-pending applications above referred to and the process provided by the present invention may be considered a novel and advantageous combination of the processes provided in these two parent applications.

The accompanying diagrammatic drawing illustrates one specific form of apparatus embodying the various cooperative features of the invention and in which the process of the invention may be conducted.

Referring to the drawing, charging stock for the process, which preferably comprises crude petroleum or other oil of relatively wide boiling range and contains a substantial quantity of gasoline or gasoline fractions of unsatisfactory antiknock value, is supplied through line i and valve 2 to pump 3 wherefrom it is fed through line I and may be thence directed through line I, valve 6 and line 9 into distilling and fractionating column l;l. Preferably, the charging stock is heated to effect fractional distillation of the charging stock.

Heating of the charging stock may be supplied not illustrated, but, in the preferred embodiment of the invention, at least a substantial portion of the heat required for fractional distillation of the charging stock is supplied thereto by its indirect heat exchange with highly heated products discharged from the reforming coil of the system. This is accomplished in the case here illustrated by directing the charging stock through valve I in line 4 into and through heat exchanger 3, wherein said heat exchange is accomplished. as will be later described, and wherefrom the heated charging stock is directed through line 3 and valve l into distilling and fractionating column ll.

distillation in column ll into any desired number of selected relatively low-boiling and high-boiling fractions. In case the charging stock contains appreciable quantities of components which are desirable as one or more final products of the process, such as, for example, Diesel fuel, lubricating stock, or the like, the same are preferably removed as selected fractions from one or more suitable points in the fractionator and supplied thence to cooling and storage elsewhere. as dedistillation temperature prior to its introduction thereto in column II in any well known manner.

The charging stock is separated by fractional sired; Line l2 and valve I3 are provided, in the case here illustrated, to serve as an illustration of suitable means whereby selected intermediate fractions of the charging stock may be recovered from column II to be removed from the system without subjecting the same to cracking treatment.

All or selected fractions of the charging stock boiling above the range of gasoline may be reriiiified from column I I and directed, for example, through line It and valve i5'to pump i6 by means of which they may be supplied, all or in part, through line l1, valve 18 and line 9! to conversion, as will be later described, in heating coil 43 or this material may be directed, all or in part, from line H through line I9 and valve 26 into fractionator 56 to serve as a cooling and reflux ing medium in this zone.

Selected low-boiling fractions of the charging stock, which are of controlled composition and may consist predominantly of gasoline or selected low-boiling gasoline fractions, or which may,

above the range of gasoline, are directed from the upper portion of column H through line 21 and valve 22 to condenser 23 wherefrom the resulting distillate and any uncondensed gases are directed throughline 24 and valve 25 to collection and separation in receiver 26. The uncondensed gases may be released from receiver 23 and from the system through line 21 and valve 23 to storage or elsewhere, as desired, or they may, when desired, be directed by well known means, not illustrated, to absorption in absorber ill. All or a portion of the distillate collected in receiver 26 may, when desired, be directed therefrom through line 29 and valve 30 to storage or to any desired further treatment.

In case the charging stock does not contain any substantial quantity of good antiknock gasoline fractions, the total components of the charging stock boiling within the range of gasoline, plus any desired higher boiling fractions of the character above mentioned, are collected, in the manner previously described, in receiver 26 and diin heating coil 31.

In case the charging stock contains a substantial quantity of low-boiling gasoline fractions of satisfactory antiknockvalue, they are preferably collected, in the manner previously described, in receiver 26 and recovered therefrom as a final product of the process. In the latter case, higher boiling gasoline fractions of inferior antiknock value are removed as a sidestream from column ii, together with any desired higher boiling components of the charging stock, such as previously mentioned, which may be advantageously cracked to produce additional yields of good quality gasoline under the reforming conditions employed in heating coil 31. Provision is made, in the case here illustrated, for removing a selected side-stream of the nature above mentioned from column H and directing the same through line 38 and valve 39 to pump 33 wherefrom it may be directed, all or in part, through line 3|, valve 35 and line' 36 to treatment, as will be later described, in heating coil The relatively high-boiling components of the charging stock supplied, as previously described,

to heating coil 40, as well as the reflux condensate supplied, as will be later described, to heating coil 40 from fractionator 56, are subjected to cracking at the desired temperature and superatmospheric pressure as it passes through heating coil 40, by means of heat supplied from furnace 4|. The resulting heated products are discharged -from heating coil 40 through line 42 and may be directed through line 43, valve 44 and line 45 into vaporizing and separating chamber 46, or, when desired, these heated products may be afforded additional cracking time, at substantial superatmospheric pressure in reaction chamber 49, to which they may be supplied from coil 40 through line 41 and valve 48.

Chamber 49, when employed, may be operated at substantially the same or somewhat lower superatmospheric pressure than that employed at the outlet of heating coil 40 and, although not indicated in the drawing, chamber 49 is preferably insulated to conserve heat. In the particular case here illustrated, the vaporous and liquid conversion products'are withdawn in commingled state from the lower portion of chamber 49 and directed therefrom through line 50, valve 5|, line 43 and line 45 into chamber 46.

In the particularcase here illustrated, products from heating coil 5i! are also supplied, as will be later described, to chamber 46 and the commingled materials in this zone are separated into vaporous and non-vaporous components. Chamber 46 is preferably operated at substantially reduced pressure relative to the pressures employed in heating coils 31 and 40, as well as relative to the pressure employed in chamber 49, when the latter zone is utilized. The reduction in pressure serves to effect appreciable further vaporization of the liquid products supplied to chamber 46 and the operating conditions of the process may be controlled to effect the production of either liquid residue or substantially dry coke in chamber 46. When the non-vaporous product remaining in chamber 46 is liquid residue, it may be removed from the lower portion of this zone through line 52 and valve 53 to cooling and storage or elsewhere, as

desired. When the non-vaporous residue pro-.

duced in chamber 36 is substantially dry coke, it may be allowed to accumulate within this zone until the chamber is substantially filled or until its operation is completed for any other reason, following which the coke may be removed in any well known manner, not illustrated, and the chamber cleaned and prepared for further operation. Preferably, when theprocess is conducted for the production of coke as a final residual product in chamber 46, a plurality of coking cham bers similar to chamber 46 is employed and, in such cases; two or more coking chambers preferably are alternately operated, cleaned and prepared for further operation in order that the coking stage, in common with the rest of the system, may be operated continuously.

The vaporous products are directed from the upper portion of chamber 46-through line 54 and valve 55 andare introduced into fractionaupper portion offfractionator 66 through line 61 and valve 58 to condensation and cooling in condenser 59. The resulting distillate and uncondensed gases are directed from condenser 59 through line 60 and vale, 6| to collection and separation in receiver 62. The uncondensed gases separated from the distillate in receiver 62 may be released therefrom and from the system through line 63 and valve 64 or they may, when desired, be directed, all or in part, from line 63 through line 65. and valve 66 to absorber N10. The distillate collected in receiver 62 may be removed, all or in part, from the system through line 6'l and valve 68 to cooling and storage or to any desired further treatment or it may be first subjected to stabilization, as will be later described.

When desired, regulated quantities of the distillate collected in receiver 62 may be returned therefrom by well known means, not illustrated, to the upper portion of fractionator 56 to serve as a cooling and refluxing medium in this zone. The invention also contemplates the return of regulated quantities of the distillate collected in receiver 26 to the upper portion of column ll by well known means, not illustrated, to serve substantial quantities of dissolved normally gaseo ous products in excess of those required for a gasoline of the desired vapor pressure. The invention therefore provides for stabilization of the distillate to reduce its vapor pressure to the desired degree by liberating regulated quantities of the dissolved normally gaseous products""therefrom. This is accomplished, in the case here illustrated, by directing distillate from receiver 62 through line 69 and valve 10 to pump H. wherefrom it is directed through line I2, valve 13, heat exchanger 14, line 15 and valve 16 into stabilizer TI. The purpose of heat exchanger 14 is to reheat the distillate supplied to stabilizer 11 sufliciently to effect appreciable vaporization thereof in the stabilizer. This is accomplished in' the present instance by passing the distillate through heat exchanger 14 in indirect heat exchange with relatively hot reboiled bottoms from the stabilizer, the latter being directed to heat exchanger 14' through line 18 and valve 19 and discharged from the heat exchanger through line 80 and valve 8| to further cooling and storage or elsewhere, as desired. Any other well known means of reheating the distillate to the desired temperature, within or prior to its introduction into stabilizer 11, may be employed within the scope of the invention.

Any desired conventional form of stabilizer may be employed within the scope of the invention and, in the particular case here illustrated, in order to establish equilibrium conditions in this zone, additional heat is supplied to the stabilizer bottoms to reboil the same, and cooling is provided in the upper portion of the stabilizer. Reboiling of the stabilizer bottoms is accomplished, in the case here illustrated, by passing a suitable heating medium through close coil 82 in the lower portion of the stabilizer. The desired degree of cooling may be accomplished in the upper portion of the stabilizer by passing a suitable cooling medium through a closed coil 83 in this zone and/or by the introduction of a suitable cooling medium through line 84 and valve 85 into direct contact with the gases in the upper portion of the stabilizer.

The rebolled and stabilized distillate, which comprises the desired flnal gasoline product of the cracking and reforming steps, is removed from the lower portion of the stabilizer and from the system, in the manner previously described. The normally gaseous products liberated from the distillate by stabilization thereof in stabilizer 11 will contain a substantial quantity of desirable high-boiling components, such as gases containing 3-carbon atoms, and more, to the molecule and, more particularly, readily polymerizable olefinic gases such as propene and butenes.

' These liberated gases are directed from the upper portion of the stabilizer through line 88, valve 81 and line 85 and are introduced, either alone or together with the normally gaseous products recovered from receiver 82, into absorber I88.

The total reflux condensate formed in fractionator 58 may, when desired, be removed from the lower portion of this zone and directed through line 88 and valve 89 to pump 98 by means of which it is supplied through line 9I and valve 92 to further cracking in heating coil 48, in the manner previously described. Preferably, however, the reflux condensate formed in fractionator 58 is separated by fractional condensation of the vapors in this zone into selected relatively lowboiling and high-boiling fractions, in which case, only thehigh-boiling fractions are supplied, as previously described, to further cracking in heatingjcoil 48, while the selected lower boiling fractions are removed from one or a plurality of suitable intermediate points in the fractionator and directed therefrom to further cracking in heating coil 31. illustrated, for directing light reflux condensate from fractionator 58 through line 93 and valve 94 to pump 95 by means of which it is fed through line 98 and may be thence supplied, all or in part, through line 91, valve 98 and line 38 to heating coil 31.

The function of absorber I88, which may be any conventional form of absorption or scrubbing apparatus, .is to separate the desired highboiling components of the gases, such as above mentioned, from their lower boiling components. This is ac complished by the use of an absorber oil of selected characteristics which will recover, by selective absorption, a substantial portion of the gases containing more than 2-carbon atoms to the molecule and including substantially all of the propane and but'ene fractions. The unabsorbed low-boiling gases are released from the upper portion of absorber I88 through line IM and valve I82 to storage or elsewhere, as desired. In accordance with the provisions of this in: vention, the absorber oil supplied to absorber I88 comprises a portion or all of the light oil cracking stock for heating coil .31. In accordance with this provision of the invention, regulated quantities of the selected low-boiling components of the charging stock supplied, as previously described, to pump 33, may be diverted from line 34 through line I83 and valve I84 into line 98 and thence directed through valve I85 in this line into the upper portion of absorber I88, or regulated quantities of the selected lowboiling. fractions of the reflux condensate from fractionator 58 may be directed through valve I88 in line 98 and thence through valve I85 in this line to the upper portion of absorber I88, or a mixture of the low-boiling components of the charging stock and the low-boiling reflux condensate from fractionator 58 may be utilized as absorber oil. Preferably, the absorberoil is Provision is made, in the case here cooled to a relatively low temperature prior to its introduction into the absorber. This cooling may be accomplished in any desired manner and, in the particular case here illustrated, cooler I81 is provided, through which the absorber oil passing through line 98 may be diverted by means of lines I88 and H8 controlled, respectively, by valves I89 and III.

The enriched absorber oil recovered from the lower portion of absorber I88, which preferably contains substantially all of the readily polymerizable olefinic gases, such as propene and butenes, supplied to the absorber, as well as corresponding parafflnic compounds and any higher boiling components of the gases, is directed through line ,2 and valve II3 to pump H4 by means of which it is supplied through line I I5, valve H8 and line 38 to treatment in heating coil 31.

A furnace I28, of any suitable form, supplies the required heat to the relatively low-boiling oils and high-boiling-gases passing through heating coil 31 to effect the desired treatment of the mixture, preferably at a substantial superatmospheric pressure. Although heating coil 31 and furnace I28 are illustrated in a conventional manner'in the drawing, this equipment preferably comprises one of the well known forms of heater commonly used for reforming service, by means of which the materials passing therethrough are quickly heated to the desired relatively high temperature and then maintained for a predetermined time at a substantial constant temperature relatively close to the maximum temperature previously attained. The preferred conditions of operation maintained in heating coil 31, which will be later specified, are regulated to effect reforming treatment of the gasoline or gasoline fractions supplied to this zone, whereby to materially improve their antiknock value, and at the same time effect cpnversion of any higher boiling oils supplied thereto to produce additi'onal yields of good antiknock gasoline therefrom and, further, effect conversion of the gases to produce additional yields of good antiknock compounds boiling 'within the range of gasoline.

The highly heated products resulting from the treatment afforded the mixture in heating coil 31 are discharged from this zone through line I2I and may be directed therefrom, all or in part, through line 'I22, valve I23, valve I24 and line 45 into chamber 48-, wherein they commingle with the conversion products supplied to this zone from heating coil 48 or from reaction chamber 49, the resultant mixture being subjected ini-chamber l8 and the subsequent equipment to the treatment previously described.

Preferably, in order to definitely control the conversion time afforded the mixture supplied to heating coil 31, the products discharged from this 'zone are cooled to a sufficiently low temperature to prevent any excessive further conversion following their discharge from the heating coil. Two methods of accomplishing this cooling are illustrated in the drawing, either or both of which may be utilized within the scope of the invention. One method of cooling the heated products discharged from heating coil 31 comprises directing, the same, all or in part, through valve I25 in line I2I into heat exchanger 8 wherein they .pass in indirect heat exchange with the charging stock supplied to this zone, as previously described, and wherefrom the partially cooled products are directed through line previously described, to chamber 46. The other method of cooling illustrated comprises diverting regulated quantities of the light reflux condensate from fractionator 56 from line 91 through line I28 and valve I29 into line I22, wherein this material commingles with the conversion products from heating coil 31, the resulting mixture being directed, in the manner previously described, to chamber 46. Preferably, in conjunction with the use of either or both of the methods of cooling above described, cooling of the products discharged from heating coil 31 is further assisted by a substantial reduction in the pressure employed in chamber 46 relative to that maintained at the outlet of heating coil 31 and, to

accomplish this, one or any desired combination of valves I23, I24, I25 and I2'l may be utilized for effecting the desired pressure reduction.

The preferred range of operating conditions which may be employed to successfully conduct the process, in an apparatus such as illustrated and above described, may be approximately. as follows: E

The temperature to which the charging stock is heated to effect its fractional distillation will,

of course, vary depending upon the type of chargingstock employed and upon the pressure conditions utilized in the distilling zone. When distillation is accomplished at atmospheric or 0 substantially superatmospheric pressure, the

40 pounds persquare inch is maintained at this point in the system. When a high pressure reaction chamber succeeding the heavy oil heating coil is employed, the pressure maintained in this zone may be substantially the same or somewhat lower than that employed at the outlet of the heavy oil heating coil and, as previously mentioned, the reaction chamber is preferably insulated to conserve heat and maintain an active cracking temperature in this zone.

The temperature employed at the outlet of the heating coil to which the high-boiling gases and the selected low-boiling fractions of. the reflux condensate and/or charging stock are supplied, may range, for example, from 925 to 1050" 55 F. preferably with a superatmospheric pressure of the order of 200 to 1000 pounds, or thereabouts, per square inch, at this point in the system. The highly heated products discharged from this heatingcoil are preferably cooled to a temperature of the order of. 600 to 750 F. I prior to their introduction into the vaporizing and separating chamber, although the temperature of these products may be somewhat higher, for example,'from 800 to 850 F., when the vaporizing and separating chamber is operated as a'coking zone: v

The vaporizing and separatingor coking zone may be operated at any desired; pressure ranging from 1'00 pounds; or therabouts per square inch,

70 uperatmospheric,uowntq subs'tantially atmospheric" pressure" and the succeeding fractionatingj bQnde n'sing and conecting equipment ma be operated: t substantially the: same or somewhatlower pressure f any desired pressures "ranging from, substantially atmospheric to 350 pounds or more, superatmospheric, may be utilized in the stabilizing and absorption equipment, the preferred range being from 125 to 350 pounds in the stabilizer and from 100 to 225 pounds in the absorber.

As a specific example of an operation of the process as conducted in an apparatus of the character illustrated and above described, the charging stock is a mixed-base crude of approxitely 36 A. P. I. gravity which contains. approximately 10% of good ant'iknock. gasoline fractions boiling up to approximately 290 F., approximately of the materials boiling up to 420 F. and approximately 25% of good quality asphaltic residue.

' This charging stock is heated by indirect heat exchange with the products discharged from the heating coil 2? to a temperature of approximately 560 F., at a superatmospheric pressure of approximately pounds per square inch, and

thence introduced into the distilling andfractionating column which is maintained at substantiaiiy the same pressure. Steam is introduced into the lower portion of the distilling column to assist the distillation and approximately 25% of good quality asphaltic residue based on the charging stock is recovered as bottoms from the distilling zone. Approximately 10%, based on the charging stock of low-boiling gasoline fractions having a satisfactory antiknock value, is recovered as overhead distillate from the distilling and fractionating column. A

side-stream consisting of the remainder of the straight-run gasoline and additional fractions of the crude boiling up to approximately 500 F. is removed from the distilling and fractionating column for use as absorber oil and reforming stock. The additional fractions of the crude having a'boiiing range intermediate that of the light side-stream and the asphaltic bottoms and amounting to approximately 35% of the crude,

by volume, are withdrawn as a. separate sidestr'eam from the distilling and fractionating column and supplied to the, relatively heavy oil cracking coil together with high-boiling fractions of the reflux condensate formed in the fractionator of the cracking system.

A conversion temperature of approximately 970 F. and a superatmospheric pressure of approximately 350 pounds persquare inch is maintained at the outlet of the heavy oil cracking coil and the heated products from this zone are supplied directly to the vaporizing and separating chamber, which is maintained at a superatmospheric pressure of approximately 90 pounds per square inch. The high pressurereaction chamber is not utilized in this operation.

-'Ii'ie gasoline product collected in the receiver of the cracking system has an end-boiling point of approximately 400 F. and is stabilized in the manner illustrated and above described, to reduce its vapor pressure to approximately 8 pounds per square inch, as determined by the Reid method.

' A side-stream of light reflux condensate, havture of approximately 70 F. prior to its introduction into the absorber. The unabsorbed gases, which consists principally of fractions having 2 and less carbon atoms to the molecule are released from the upper portion of the absorber.

The enriched absorber oil, which contains sub stantially all of the gases having 3 and more carbon atoms to the molecule, is supplied directly from the absorber to the reforming coil.

The temperature employed at the outlet of the reforming coil is approximately 995 F. and the pressure employed at this point in the system is approximately 750 pounds per square inch, superatmospheric. The highly heated products discharged from the reforming coil are cooled, partially by indirect heat exchange with the charging stock, partially by directly commingling the same with regulated quantities of the light reflux condensate from the fractionator of the cracking system and partially by pressure reduction, to a temperature of about 610 F. and are thence introduced into the vaporizing and separating chamber.

In addition to the 25%, or thereabouts, of asphaltic residue recovered as a final product of the process from the distilling and fractionating column, the above described operation will yield per barrel of charging stock approximately 56% of gasoline which consists of a blend of the light straight-run gasoline fractions and gasoline produced in the cracking and reforming steps. The remaining 19% or thereabouts, based in charging stock, is accounted for as residual liquid, suitable as fuel oil, which is recovered from the vaporizing and separating chamber, and the small amount of gas and loss. The blended gasoline product has an end-boiling point of approximately 400 F., an antiknock value, as determined by the motor method, of approximately '72 and a vapor pressure (Reid) of approximately 8 pounds per square inch.

I claim as my invention:

1. A process for the treatment of hydrocarbon oils which comprises fractionally distilling a hydrocarbon charging oil of relatively wide boiling range and therebyseparating thesame into selected relatively low-boiling and high-boiling fractions, cracking resultant selected high-boiling fractions of the charging oil and reforming resultant selected low-boiling fractions of the charging oil, which comprise at least a substantial quantity of gasoline fractions of poor antiknock value, effecting said cracking and said reforming under independently controlled conditions of cracking temperature and superatmospheric pressure, partially cooling the heated products of the reforming step and accomplishing said cooling, at least in part, by passing heated products of said reforming step in indirect heat exchange with the charging oil, whereby to prevent any excessive continued cracking of the reformed products and whereby to supply heat to the charging oil for saidfractional distillation thereof, separating vaporous and non-vaporous components of the resultant cracked and partially cooled reformed products, fractionating the vapors to form light and heavy reflux condensates, returning heavy reflux condensate formed by said fractionation to the cracking step for further cracking treatment, returning light re flux condensate formed by said fractionation to the reforming step for further cracking treatment, subjecting the fractionated vapors of the desired end-boiling point, which consist predominantly of materials boiling within the rangeof gasoline and normally gaseous products, to condensation, separating the resulting distillate and. uncondensed gases, stabilizing the distillate to reduce its vapor pressure to the desired degree by liberating regulated quantities of dissolved normally gaseous products therefrom, recovering the stabilized distillate, intimately contacting the gasesliberated from the distillate by said stabilization with at least a portion of the oil subsequently supplied, as previously described, to said reforming step and thereby absorbing in the latter desirable high-boiling components of said gases including readily polymerizable olefins, removing the unabsorbed low-boiling gases from the system and supplying the resulting enriched lected relatively low-boiling and high-boiling,

fractions, cracking resultant selected high-boiling fractions of the charging oil and reforming resultant selected low-boiling fractions of the charging oil, which comprise at least a substantial quantity of gasoline fractions of poor antiknock value, effecting said cracking and said reforming under independently controlled conditions of cracking temperature and superatmospheric pressure, partially cooling the heated products of said reforming step sufliciently to prevent an excessive continued cracking thereof and accomplishing said cooling, at least in part, by indirect heat exchange between the charging oil and hot reformed products, whereby to supply heat to the charging oil for said fractional distillation thereof, separating vaporous and nonvaporous components of the resultant cracked and. partially cooled reformed products, fractionating the vapors to form light and heavy reflux condensates, returning heavy reflux condensate formed by said fractionation to the cracking step for further cracking treatment, returning light reflux condensate formed by said fractionation to the reforming step for further cracking treatment, subjecting the fractionated vapors of the desired end-boiling point, which consists predominantly of materials boiling within the range of gasoline and normally gaseous products, to condensation, separating the resulting distillate and uncondensed gases, stabilizing the distillate to reduce its vapor pressure to the desired degree by liberating regulated quantities of dissolved normally gaseous products therefrom, recovering the stabilized distillate, intimately contacting the gases liberated from the distillate by said stabilization and gases previously separated from the distillate following'said condensation with at least a portion of the oil subsequently supplied, as previously described, to said reforming step, thereby absorbing in the latter desirable high-boiling components of said gases, including readily polymerizable olefins, removing the unabsorbed low-boiling gases from the system and supplying the resulting enriched absorber oil to sultant selected low-boiling fractions of the charging oil, which comprise at least a substantial quantity of gasoline fractions of poor antiknock value, effecting said cracking and said reforming under independently controlled conditions of cracking temperature and super-atmospheric pressure, passing heated products of said reforming step in indirect heat exchange with the charging oil to supply heat to the charging oil for said fractional distillation thereof, separating vaporous and non-vaporous components of the resultant cracked and partially cooled reformed products, fractionating the vapors to form light and heavy reflux condensates, returning heavy reflux condensate formed by said fractionation to the cracking step for further cracking treatment, returning light reflux condensate formed by said fractionation to the reforming step for further cracking treatment, subjecting the fractionated vapors of the desired end-boiling point, which consist predominantly of materials boiling within the range of gasoline and normally gaseous products, to condensation, separating the resulting distillate and uncondensed gases, stabilizing the distillate to reduce its vapor pressure to the desired degree by liberating regulated quantities of dissolved normally gaseous products therefrom, recovering the stabilized distillate, intimately contacting the gases liberated from the distillate by said stabilization with an absorber oil comprising selected low-boiling fractions of the charging oil subsequently supplied, as previously described, to the reforming step, thereby separating desirable high-boiling components of the gases, including readily polymerizable oleflns, from low-boiling components" thereof by absorption of the former and supplying the resulting enriched absorber oil to the reforming step. d

4.- A process for the treatment of hydrocarbon oils which comprises fractionally distilling a hydrocarbon charging oil of relatively wide boiling range and thereby separating the'same into selected relatively low-boiling and high-boiling fractions, cracking resultant selected high-boih' ing fractions of the charging oil and reforming resultant selected low-boiling fractions-of the charging oil, which comprise at least a substantial quantity of gasoline fractions of poor antiknock value, effecting said cracking and "said reforming under independently controlled conditions of cracking temperature and superatmospheric pressure, passing heated products of said reforming step in indirect heat exchange with the charging oil to supply heat to the charging oil for said fractional distillation thereof, separating vaporous and non-vaporous components of resultant cracked and partially cooled reformed products, fractionating the vapors to form light and heavy reflux condensates, returning heavy reflux condensate formed by said fractionation to the cracking step for further cracking treatment, returning light reflux condensate formed by said fractionation to the reforming step for further cracking treatment, subjecting the fractionatedvapors of the desired end-boiling point, which consist predominantly of materials boiling within the range of gasoline and normally gaseous products, to condensation, separating the resulting distillate and uncondensed gases, stabilizing the distillate to reduce its vapor'pressure to the desired degree by liberating'regulated quantities of dissolved normally gaseous products therefrom, recovering the stabilized idijstillate, intimately contacting the gases liberated-from the distillate by said stabilization and gases previously separated from the distillate with an absorber oil comprising selected low-boiling fractions of the charging oil subsequently supplied, as previously described, to the reforming step, thereby separating desirable high-boiling components of the gases, including readily polymerizable oleflns, from low-boiling components thereof, by absorption of the former, and supplying the resulting enriched absorber oil to the reforming step.

5. A process for the treatment of hydrocarbon oils which comprises fractionally distilling a hyydrocarbon charging oil of relatively. wide boiling range and thereby separating the same *i-nto selected relatively low-boiling and high-boiling fractions, cracking resultant selected high-boiling fractions of the charging oil and reforming resultant selected low-boiling fractions of the charging oil, which comprise at least a substantial quantity of gasoline fractions of poor antiknock value, effecting said cracking and said reforming under independently controlled conditions of cracking temperature and superatmospheric pressure, passing heated products'of said reforming step in indirect heat exchange with the charging oil to supply heat to the charging oil for said fractional distillation thereof,'separating vaporous and non-vaporous components of the resultant cracked and partially cooled reformed products, fractionating the vapors to form light and heavy reflux condensates, returning I heavy reflux condensate formed by saidfractionation to the cracking step for further cracking treatment, returning light reflux condensate formed by said fractionation to the reforming ,step for further cracking treatment, subjecting the fractionated vapors of the desired end -boiling point, which consist predominantly of materials boiling within the range of gasoline and normally gaseous products, to condensation, separating the resulting distillate and uncondenser gases, stabilizing the distillate to reduce its vapor pressure to the desired degree by liberating regulated quantities o'f'dissolved normally gaseous products therefrom, recovering the stabilized distillate, intimately contacting the gases liberated from the distillate by said stabilization with absorber oil comprising selected low-boiling fractions of the reflux' condensate formediby said fractionation,

thereby separating desirable high-boiling components of the gases, including readily polymeriz# able oleflns,.from low-boiling components thereof, by absorption of the former, and supplying the resulting enriched absorber oil to the reforming step in indirect heat exchange with the charging voil to supply heat to the charging oil for said fractional distillation thereof, separating vapor- I ons and non-vaporous components of the resultant cracked and partially cooled reformed prodflux condensate formed by said fractionation to the cracking step for further cracking treatment, returning light reflux condensate formed by said fractionation to the reforming step for further cracking treatment, subjecting the fractionated vapors of the desired end-boiling point, which consist predominantly of materials boiling within the range of gasoline and normally gaseous products, to condensation, separating the resulting distillate and uncondensed gases, stabilizing the distillate to reduce its vapor pressure to the desired degree by liberating regulated quantities of dissolved normally gaseous products therefrom, recovering the stabilized distillate, intimately contacting the gases liberated from the distillate by said stabilization and gases previously separated from the distillate with absorber oil comprising selected low-boiling fractions of the reflux condensate formed by said fractionation, thereby separating desirable high-boiling components of the gases, including readily polymerizable oleflns, from low-boiling components thereof, by absorption of the former, and supplying the resulting enriched absorber oil to the reforming step. v

7. A process for the treatment of hydrocarbon oils which comprises fractionally distilling a hydrocarbon charging oil of relatively wide boiling range and thereby separating the same into selected relatively low-boiling and high-boiling fractions, cracking resultant selected highboiling fractions of the charging oil and reforming resultant selected low-boiling fractions of the charging oil, which comprise at least a substantial quantity of gasoline fractions of poor antiknock value, effecting said cracking and said reforming under independently controlled conditions of cracking temperature and superatmospherlc pressure, passing heated products of said reforming step in indirect heat exchange with. the charging oil, whereby, to partially cool the formerand supply heat to the charging oil for said fractional distillation thereof, separating vaporous and non-vaporous components of the,

. resultant cracked and partially cooled reformed products, fractionating said vapors to form reflux condensate, returning said reflux condensate to further cracking treatment within the system, subjecting the fractionated vapors of the desired end-boiling point, which consist predominantly of material boiling within the range of gasoline and normally gaseous products, to condensation, separating the resulting distillate and uncondensed gases, stabilizing the distillate to reduce its vapor pressure to the desired degree by liberating regulated quantities of dissolved normally gaseous products therefrom, recovering the stabilized distillate, intimately contacting the gases liberated from the distillate by said stabilization with a light distillate subsequently supplied to said reforming step and thereby absorbing in the latter desirable high-boiling components of said gases including readily polymerizable OIGfiDSyI'G- moving the unabsorbed low-boiling gases from the system and supplying the resulting enriched absorber oil to said reforming step.

8. A process for the treatment of hydrocarbon oils which comprises fractionally distilling a hydrocarbon charging oil of relatively wide boiling range and thereby separating the same into selected relatively low-boiling and high-boiling fractions, cracking resultant selected high-boiling fractions of the charging oil and reforming resultant selected low-boiling fractions of the charging oil, which comprise at least a substantial quantity of gasoline fractions of poor antiknock value, effecting said cracking and said reformin under independently controlled conditions of cracking temperature and superatmospherlc pressure, passing heated products of said reforming step in indirect heat exchange with the charging oil, whereby to partially cool the former and supply heat to the charging oil for said fractional distillation thereof, separating vaporous and nonvaporous components of the resultant cracked and partially cooled reformed products, fractionating said vapors to form reflux condensate, returning said reflux condensate to further cracking treatment within the system, subjecting the fractionated vapors of the desired end-boiling point, which consist predominantly of materials boiling within the range of gasoline and normally gaseous products, to condensation, separating the resulting distillate and uncondensed gases stabilizing the distillate to reduce its vapor pressure to the desired degree by liberating regulated quantities of dissolved normally gaseous products therefrom, recovering the stabilized distillate, intimately contacting the gases liberated from the distillate by said stabilization and gases previously separated from the distillate with a light distillate subsequently supplied to said reforming step and thereby absorbing in the latter desirable high-boiling components of said gases including readily polymerizable oleflns, removing the unabsorbed low-boiling gases from the system and supplying the resulting enriched absorber oil to said reforming step.

' 9. A process for the treatment of hydrocarbon oils which comprises fractionally distilling a hydrocarbon-charging oil of relatively wide boiling range and thereby separating the same into selected relatively low-boiling and high-boiling fractions, cracking resultant selected high-boiling tions of cracking temperature and superatmos pheric pressure, passing heated products of said reforming step in indirect heat exchange with the charging oil, whereby to partially cool the former and supply heat to the charging oil and said fractional distillation thereof, separating vaporous and non-vaporous components of the resultant cracked and partially cooled reformed products, fractionating said vapors toform reflux condensate, returning said reflux condensate to further cracking treatment within the system, subjecting the fractionated vapors of the desired end-boiling point, which consist predominantly of materials boiling within the range of gasoline and normally gaseous products, to condensation, separating the resulting distillate and uncondensed gases, stabilizing the distillate to reduce its vapor pressure to the desired degree by liberating regulated quantities of dissolved normally gaseous products therefrom, recovering the stabilized distillate, intimately contacting the gases liberated from the distillate by said stabilization with an absorber oil comprising selected low-boiling fractions of the charging oil, whereby to separate desirable high-boiling components of the gases, including readily polymerizable oleflns, from lower boiling components thereof, by absorption of the former, and supplying the resulting enriched absorber oil to the reforming step.

10; A process for the treatment of hydrocarbon oils which comprises fractionally distilling hydrocarbon charging oil of relatively wide boiling range and thereby separating the same into selected relatively low-boiling and high-boiling fractions, cracking resultant selected high-boiling fractions of the charging oil and reforming resultant selected low-boiling fractions of the charging oil, which comprise at least a substantial quantity of gasoline fractions of poor antiknock value, effecting said cracking and said reforming under independently controlled conditions of cracking temperature and superatmospheric pressure, passing heated products of said reforming step in indirect heat exchange with the charging oil whereby to partially cool the former and to supply heat to the charging oil and said fractional distillation thereof, separating vaporous and non-vaporous components of the resultant cracked and partially cooled reformed products, fractionating said vapors to form reflux condensate, returning said reflux condensate to further cracking treatment within the system, subjecting the fractionated vapors of the desired end-boiling point, which consist predominantly of materials boiling within the range of gasoline and normally gaseous products, to condensation, separating the resulting distillate and uncondensed gases, stabilizing the distillate to reduce its vapor pressure to the desired degree by liberating regulated quantities of dissolved normally gaseous products therefrom, recovering the stabilized distillate, intimately contacting the gases liberated from the distillate by said stabilization and gases previously separated from the distillate with an absorber oil comprising selected low-boiling fractions of the charging oil, whereby to separate desirable high-boiling components of the gases, including readily polymerizable olefins, from lower boiling components thereof, by absorption of the former, and supplying the resulting enriched absorber oil to the reforming step.

11, A process for the treatment of hydrocar bon oils which comprises fractionally distilling an oil of relatively wide boiling range and thereby separating the same into selected relatively low-boiling and high-boiling fractions, supplying selected high-boiling fractions to a heating coil and therein cracking the-same at elevated temperature and superatmospheric pressure, supplying selected low-boiling fractions of the charging oil, which comprise at least a substantial quantity of poor antiknock gasoline fractions, to a separate heating coil and therein heating the same under cracking conditions of elevated temperature and superatmospheric pressure regulated to effect a material improvement in the the vapors from said separating chamber to a,

fractionator and therein condensing their components boiling above the range of the desired final gasoline product as reflux condensate, returning reflux condensate formedbysaid fractionation to the first mentioned heating coil for further cracking, subjecting the fractionated vapors of the desired end-boiling point to condensation, separating the resulting distillate and uncondensed gases, stabilizing the distillate to rethereof, by absorption 'of the former, and supplying the resulting enriched absorber oil to the .second mentioned heating coil.

12. In a process for the treatment of hydrocarbon oils which comprises fractionally distilling an oil of relatively wide boiling range and thereby separating the same into selected relatively lowboiling and high-boiling fractions, supplying'selected high-boiling fractions to a heating coil and therein cracking the same at elevated temperature and superatmospheric pressure, supplying selected low-boiling fractions of the charging oil, which comprise at least a substantial quantity of poor antiknock gasoline fractions, to a separate heating coil and therein heating the same under cracking conditions of elevated temperature and superatmospheric pressure regulated to effect a material improvement in the antiknock value of said gasoline fractions, discharging resultant highly heated productsfrom the last mentioned heating coil, cooling the same sufficiently to prevent any excessive further cracking thereof, introducing the resulting partially cooled products and products resulting from the first mentioned cracking operation into a reduced pressure separating chamber and therein separating vaporous arid non-vaporous components of the commingled products, supplying the vapors from said separating chamber to a fractionator and therein condensing as, reflux condensate substantially all of their components with the exception of good antiknock gasoline and normally gaseous products, separating the reflux condensate formed by said fractionation into selected low-boiling and high-boiling fractions, returning the latter to the first mentioned heating coil for further cracking treatment, returning said selected low-boiling fractions of the reflux condensate to the second mentioned heating coil for further cracking treatment, subjecting the fractionated vapors of the desired end-boiling point to condensation, separating the resulting distillate and uncondensed gases, stabilizing the distillate to reduce its vapor pressure to the desired degree by liberating regulated quantities of dissolved normally gaseous products therefrom, supplying gases liberated from the distillate by said stabilization to an absorber, therein contacting the same with at least a portion of the oil subsequently supplied, as previously described, to the second mentionedheating coil and thereby separating desirable high-boiling components of the gases, including readily polymerizable olefins, from lower boiling components thereof. by absorption of the former, and supplying the resulting enriched absorber oil to the second mentioned heating coil.

13. A process for the treatment of hydrocarbon oils which comprises fractionally distilling an oil of relatively Wide boiling range and therecooling the same sufiiciently to prevent any excessive further cracking thereof, introducing the resulting partially cooled products and products from the first mentioned cracking operation into a reduced pressure separating chamber and therein separating vaporous and non-vaporous components of the commingled products, supplying the vapors from said separating chamber to a fractionator and therein condensing as reflux condensate substantially all of their components with the exception of good antiknock gasoline and normally gaseous products, separating the reflux condensate formed by said fractionation into selected low-boiling and high-boiling, fractions, returning the latter to the first mentioned heating coil for further cracking treatment,returning said selected low-boiling, fractions of the reflux condensate to the second mentioned heating coil for further cracking treatment, subjecting the fractionated vapors of the desired end-boiling point to condensation, separating the resulting distillate and uncondensed gases, stabilizing the distillate to reduce its vapor pressure to the desired degree by liberating regulated quantities of dissolved normally gaseous products therefrom, supplying gases liberated 'from the distillate by said stabilization and gases previously separated from the distillate to an absorber, therein contacting the same with at least a portion of the oil'subsequently supplied, as previously described, to the second mentioned heating coil and. thereby separating desirable high-boiling components of the gases, including readily polymerizable olefins, from lower boiling components thereof, by absorption of the former, and supplying the resulting enriched absorber oil to the second mentioned heating coil.

CHARLES H. ANGELL.

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