US2017874A - Treatment of hydrocarbons - Google Patents

Description

P. H. SULLIVAN TREATMENT OF HYDROCARBONS Oct. 22, 1935.

2 Sheets-Sheet 2 Filed Oct. 26, 1934 A TTORNEY asiakwtkm 23 four Mmw l a HHl l l l l l lH rmmaoeeniaas uN- n STATES/PATENT OFFKIE murmur or rrrnaocmons Pike n. SuIllvam'New Rochelle, N. 1., 1m to Gasoline Products Company, Inc., Newark, N. 1.. a corporation of Delaware Application mm 2c, 1034,- serm'no. 150,039

a Claims. (01. 190-9) i Myinvention relates to the thermal treatment of hydrocarbons and more particularly to a process for converting hydrocarbon oil and hydro-' carbon gas into relatively low-boiling hydrocari'bon'oil suitable for use as motor fuel.

My invention has an especial relation to oilcracking processes of the so-called "combinationunit" type in which a heavy hydrocarbon oil, such, forexample, as reduced crude, containing residual constituents, is subjected to a comparatively mild cracking temperature under superatmospheric pressure for. the purpose of. producing a clean condensate suitable as a charging stock for a vapor-phase cracking operation, the products a of the mild cracking operation being fractionated to recover clean condensate, the clean condensate being separately subjected tomore drastic crackingconditions, preferably in the vapor phase, and

the productsbeing fractionated to recover gases, i naphtha or gasoline and tars. I

It has previously been proposed in the operation (iron-cracking units to recycle gases produced in. the cracking operation to some point in thecracking operation, sometimes with addii tional heating of the gases; in order that the heated gases may serve as a convection medium to assist in the cracking and distilling operation.

Vapor-phase cracking conditions such as those commonly employed today are not, however,

) especially conducive to the polymerization of gaseous ,oleflns. 0n the contrary, .the present tendencyotoward carrying out vapor-phase operations at increasingly high temperatures leads to the production of increasing quantities of fixed gases,

5 these gases being relatively highly unsaturated in character, that is to say containing increas ingly large amounts of gaseous olefins. My invention therefore has for an object the provision of a process of the so-called combination-un'it type wherein gases produced in the cracking of hydrocarbon oil may be caused to be in part reconverted or polymerized to lowboiling normally liquid products useful as motor fueland of very high anti-knock value.

My invention has for a further object the provision of a process wherein a gas-polymerization operation may advantageously be conducted in conjunction with, or as a part of, an oil-cracking operation. of the general character indicated hereinabove, with a minimum of additional equipment and difllculty and with marked advantage tothe operator. 7

According to my invention, gases produced in the cracking of hydrocarbon oil in a combination 5 unit of the character generally indicated herein-' above, together if desired with hydrocarbon gas from an additional source such as unsaturated gases produced by cracking gases liberated in the distillation of crude petroleum, are fractionated to separate hydrogen and methane and to effect a concentration of gaseous olefins and the thus concentrated gases are returned to the so-called viscosity-breaking zone of the combination operation, that is to say to that zone wherein a heavy oil stock such as reduced crude which is 10 unsuitable for vapor-phase cracking operations is subjected to a comparatively mild cracking temperature, preferably under superatmospheric pressure, to eifect the production of clean charging stock suitable for separate vapor-phase crackmg. I have found that the conditions under which such viscosity-breaking operations are conducted are much more effective insofar as the polymerization of gaseous oleiins to normally liquid low-boiling hydrocarbon oils is concerned 4 than are the conditions under which vapor-phase .acter indicated, reduced crude being delivered to the, viscosity-breaking stage of the same unit and I the naphtha, if desired, being subjected to reformation in a separate cracking coil with the discharge of the reformed products into the system at a convenient point, and with the delivery of the gases produced in the distillation of crude in petroleum, preferably after cracking and fractionation to increase their olefin content, to the viscosity-breaking stage along with fractionated l gases recovered from the vapor-phase cracking and reforming operations.

My invention further contemplates and has for further objects such additional operative advantages and improvements as may hereinafter be found to obtain.

In order that my invention may be more clear- 00 ly set forth and understood, I now describe, with reference to the accompanying drawings forming a part of this specification, various preferred forms and manners in which my invention may be practiced and embodied. In these drawings. II

Fig. 1 is a more or less "diagrammatic elevational view of apparatus for carrying out an oil-. cracking and gas-polymerizing operation in accordance with my invention, the view being intended to serve as a flow diagram of one modification of my process; and

Fig. 2 is a similar view of an alternative form of apparatus for practicing my invention in various other modifications thereof.

Similar reference numerals designate similar parts in each of the views of the drawings.

Referring now to the drawings, and more particularly to Fig. 1, I have shown a so-called combination unit" comprising in part a high-temperature or vapor-phase oil-cracking furnace l, a viscosity-breaking furnace 2 intended to operate at a lower temperature than the furnace I, an evaporator 3, a primary fractionator 4, a secondary fractionator 5 and a gas-iractionating system indicated generally by the reference numeral 6 and comprising principally an absorber 1 and a stripper 3. I

A suitable charging stock, such, for example, as a reduced crude, is introduced into the system through a line It by means of a pump i I, passing first through a heat-exchange coil l2 in the upper portion of the secondary fractionator 5, and then passing by way of line l3 into the upper portion of the primary fractionator 4, the interior of which may be provided with trays or bailles I4 and which receives hot cracked vapors from the evaporator 3 through a trap-out tray I3. In the primary fractionator 4, a partial distillation and a further heating of the charging stock takes place, residual constituents being withdrawn from the trap-out tray I 5 through a line I6 wherein is located a pump I] which serves to force the oil through a pipe coil l8 located in the furnace 2.

The temperatures and pressures which are maintained at the outletof the coil I! may vary considerably but are generally within what may be called a viscosity-breaking range, that is to say a range of temperature and pressure primarily intended to effect a conversion of the relatively heavy oil to lighter constituents suitable for further cracking under vapor-phase conditions to produce gasoline and distinguished from more drastic cracking conditions intended to produce large quantities of gasoline in a single operation.

While these temperatures may vary considerably, as will be'appreciated by those skilled in the art, in accordance with the character of the charging stock and the nature of the results desired as well as the time of treatment, I prefer to employ temperatures of from about 800 to about 925 F., and more specifically, from 850 to 875 F. The pressure may vary over a very wide range but, in any event, is not less than 200 7 pounds per square inch, and, especially in-view of the fact that, as will be shown hereinbelow, gases are introduced into the coil is for polymerization, it may be considerably higher, for example 1000 to 2000 pounds or more,the upper A limit depending primarily upon the strength of available apparatus and the balance of economy between the increased value of the products obtained by polymerization under high pressures as against the cost of pumping gas and liquid throughthe coil l8 under such high pressures.

The heated products from the coil I8 pass through a transfer line l9 wherein is located a pressure-reducing valve 20 into the evaporator 3, which is preferably maintained at a reduced pressure, for example 100 to 200 pounds per square inch, although, as is well known in the art,

the pressures carried in such evaporators may vary from a few pounds to several hundred pounds, being limited in this respect only by the necessity of carrying a lower pressure than obtains in any of the heating coils discharging thereinto.

Residual products or tar which remain unvaporized in the evaporator 3 and collect in liquid form. in the bottom thereof are withdrawn through a valved line 2|, while the liberated vapors pass upward through the trap-out tray ll into the primary fractionator 4 where they are further fractionated to some extent and serve to distill .the fresh charging stock introduced through the line l3. The remaining vapors, con- I sisting largely of gas oil and naphtha together with fixed gases, pass by way of a line 22 to the lower part of the; secondary fractionator l, the interior of which is provided with the usual plates or trays 23, and wherein these vapors are fractionated to condense and separate distillate heavierv than gasoline, i. e. gas oil. The gas oil condensate, which constitutes a clean charging stock suitable for cracking at high temperatures,

is withdrawn from the bottom of the secondary fractionator 5 through a line 24 having a valve 25 and a pump 26, and passes by way of line 24 to a pipe coil 21 located in the furnace I.

As the oil passes through the coil 21 in the furnace I it is heated to a relatively high cracking temperature, preferably under so-called vapor-phase conditions, for example at a temperature of from 850 to 1000 F. and preferably above 900 F., under a pressure of from a few pounds per square inch to several hundred pounds per square inch, preferably somewhat higher than the pressure maintained in the evaporator 3.

The highly heated cracked products then pass by way of a transfer line 28 wherein is located a pressure-reducing valve 29 into the evaporator 3,

and the vapors pass upward through'the primary fractionator 4 andinto the secondary fractionator 5, while tar or residual oil is withdrawn at 2| in the manner indicated hereinabove.

The overhead vapors from the secondary frac- 36 to the absorber I of the gas-fractionating system 6.

The purpose of the gas-fractionating system 6, as has been indicated hereinabove, is to eflect a separation of the gas into two fractions, one comprising largely hydrogen and methane which are unsuitable for polymerization, and the other fraction being relatively concentrated with respect to gaseous olefins. Various gas-fractionating systems for this purpose are known in the art, and the details of such a system neither form part of my invention in themselves nor require lengthy description here; However, the drawings illustrate the principal features of one particular type of gas-fractionating apparatus, in which the gases passing through the scrubber I are scrubbed with a suitable solvent such as liquid butane having selective properties with respect to gaseous olefins as distinguished from hydrogen and methane, such solvent beingintroduced to the scrubber I by means 01' a line 31.

The scrubbed gases, comprising largely hydrogen and'methane, or at any rate more highly concentrated in these constituents, escape from the of manifold connections 52 having valves to having a pump 55 scrubber]. throu h a valved line a. while the solvent passes through a line 80 wherein are-lo eated-a pump 4| and a. heat-exchanger toigstripper I, whichisshownasprovidedwith' a conventional heating coil 42, dephlegrnating coil 48 and suitable plates or trays 44. In the stripper 8 the absorbed gases, comparatively rich in gaseous olenns as compared to the gases entering the scrubber I, are driven off from the sol- .vent, the stripped solvent being returned by means of a pump 45 located-in the line 31 and by way ofthe heat-exchanger 4! and a cooling coil 48 tolthe serubberl gases pass out of the stripper 8 through a line 4| and are delivered by means of a pump branch, line Iii havin a valve ii to the inlet of the coil v; i2. Alternatively, or a portion of the gases thusreturned may be delivered by means various spaced points along the coil ll,-theintro-.

duction of the gases to the coil it being regulated by means of the valves 53 toprovide agradual introduction of such gases to the oil traversing the coil l2 and to make it possible to closely regulate the action taking place-in the coil i8.

Additional gas oil or clean charging stockfrom an outside source may be introduced to the vaporphase cracking coil 21 by means of a, line I4 and a valve 58 and communicatin'gwith the line 24 and, as is pointed out elsewhere in the specification, such gas oil may be drawn from the same stripping operation which is employed to produce heavier oil to be charged to the coilil. Y

Similarly, additional gases containing oleflnic constituents may be introduced into the system as I desired, the point of, introduction depending upon the-olefin concentration of suiah gases. For example gases containing say 30% or more of gaseous olefins and which do not require further fractionation for concentration thereof may be introduced by means of a line 51 having a valve 58 and which communicates with the line 48. Less highly concentrated oleilnic gases or, if desired, oleiinic gases of any degree of concentration short of that obtainable in the gas-fractionating system i, may be introduced to the line 35 through aline 59 having a valve 60, these gases being commingled with gases from the separator 32. p

As will be mad more clear hereinbelow, virgin naphtha from an outside source, for example from the same crude stripping operation which is I employed to produce a charging oil for the various operations of the combination unit which have been described hereinabove, may be subjected to crackingin a separate coil for the purpose of reformingthe same and increasing its anti-knock content, and the heated products from the reforming operation may be introduced intothe evaporator 3, the reformed gasoline in this instance being collected along with the polymerized gasoline and the cracked gasoline withdrawn from the separator 32. v

The instance which has been described hereinabove will serve to illustrate my processes carried out in conjunction with a combination-unit oilcr king operation in which the products from t high-temperature or ,vapor-phase cracking co andfrom the low-temperature or viscositybreaking' coil discharge into asingle evaporator. In Fig. 2, however, I have illustrated an operation in which the products from 'these coils discharge into separate evaporators, which are in turnconnectedto separate fractionating systems,

. instance, a' separate evaporator The concentrated oleflnic 49 and a and I have further illustrated a preferred manner of combining a unit of this character with a crude stripping operation and a gas-cracking operation as well as a naphtha-reforming operation.

In the instance shown in Fig. 2, the products from the coil ll pass to the evaporator 3 and vapors from the latter pass through the primary and secondary 'fractionators 4 and i asin the instance illustrated in Fig. 1.. However, in this 3' and fraction- 1 ator I are provided for the products from the vapor-phase cracking coil 21. .There is also provided a furnace i0 having'associated therewith an evaporator Ii and a fractionator I2, and there are also provided a gas-cracking furnace II and 16 a reforming furnace 14. In this modification, the operation may be as follows:

Crude petroleum is introduced by means of the pump ii, passing through a 'heat-exchanse coil located in the upper portion of the fractionator 5' and thence through a line 15 to a heating I leum, and preferably under a moderately elevated superatmospherlc temperature. The pre-heated crude petroleum then passes by way of a line 11 having a reducing valve ll into an evaporator Ii where a. volatilization of the lighter constituents 0 of the petroleum occurs, vapors passing upward through a trap-out tray 19 into the fractionator 12 while the residue or reduced crude is withdrawn from the evaporator 1| and passes through a line 80 having a valve 8i and a pump 82 to the primary fractionator 4 for further distillation. Residual components from this distillation pass through the line it to the coil l8 as in the instance illustrated in Fig. 1.

The fractionator I2 is operated to condense constituents heavier than naphtha, that is to say, virgin gas oil, which is withdrawn from the trap-out tray 19 through a, line 83 wherein is lo- 'cated a pump 84 and passes through the line 83 and the line 24 to the vapor-phase cracking coil 21. The highly heated products from the coil 21 pass through the transfer line 2-8 into the evaporator 3 from which heavy or tarry products may be withdrawn-through a line 84 and either discarded through a valved branch line 85 or passed through a line 88 having a valve 81 to the evaporator 3. In the event that the tarry products from evaporator 3 are passed to the evaporator 3, in the manner indicated, then it is preferable to maintain evaporator 3 under a materially lower pressure than that maintained in evaporator 3. For example, a. pressure of from 25 to 50 pounds may be maintained in 3 while a pressure of about 200 pounds is maintained in 3. As a further alternative, tar withdrawn from the evaporator 3 may be delivered tionator 5' may, however, be withdrawn from the system through a valved branch line 9i.

Overhead vapors from the fractionator 5' pass through a line 30' to a'condenser 3| and a seporator-32". gases from which are caused to passv through a line 35 andthe line 35 under the influence of the compressor 36 into the" absorber "1 of the gas-fractionating system 6, the gases from the gas-fractionating system 6 being returned by way of line 46 to the coil I3, as in the instance illustrated in Fig. l. Condensate is withdrawn from the separator 32' through a line 32 having a valve 33, and in the preferred instance illustrated passes to a blending tank 34,

although it may be separately withdrawn from the system if desired.

In this instance, the gases from the separator 32, comprising the incondensable portions of products withdrawn from the top of the secondary fractionator 5, may be withdrawn from the system through a valved conduit 35, or may pass by way of the line 35 which is provided with a valve 36 to the gas-fractionating system 6, or

may be cracked as described hereinbelow;

Overhead vapors from the fractionating tower I2 ofthe crude distillation unit pass through a line I to a condenser IN and a separator I02, from which virgin naphtha of relatively low anti-knock value is withdrawn through a line I03 having a valve I06. and a pump I05 into a reforming orcracking coil I06 located in the furnace I4 wherein the naphtha is heated to a relatively high -cracking temperature effective to increase the anti-knock value of the naphtha without greatly modifying its boiling-point characteristics. Suitable temperatures for this operation are from 950 to 1050 F., preferably about 1000 F.', and the heating is preferably conducted under a pressure in excess of 200 pounds, for example 1000 pounds or higher. The hot reformed products issue from the reforming coil I06 through a transfer line I01 and may pass either by way of a branch line I08 having a valve I09 into the evaporator 3 of the viscosity-breaking unit, or they may pass by way of a line IIO having a valve III into the evaporator 3' of the vapor-phase cracking unit.

Where the vapors pass to the evaporator 3 ofthe viscosity-breaking unit, the gasoline withdrawn from the separator 32 through the line 33 and which may be delivered, if desired, to the blending tank 94, will be of good antiknock value, and the gases removed from the separator 32 will ordinarily be 'sufliciently concentrated in gaseous olefins to warrant their introduction by way of the line 35 into the gas-fractionating system 6. Where, however, the reformed prodacts are discharged by way of the line IIO into the evaporator 3 of the vapor-phase cracking unit, the gasesissuing from the separator 32 may, if desired, be removed from the system through the line 95 and the gasoline or naphtha in the separator 32 may similarly be removed from the system or may be passed to the reforming coil I06 for further-conversion.

Gases liberated iii the crude distillation stage and separated from condensate in the separator I02 may, if desired, be withdrawn from the system, but in the preferred instance these gases pass through a line I20 having a valve I2I and, if necessary, a pump I22, to a gas-cracking coil I23 located in the furnace 13 wherein these gases are heated to a temperature of from 1250 to 1750 F. under a pressure preferably not in excess of 200 pounds per square inch to effect a conversion or crackingofgaseous paraflins to gaseous olefins suitable for polymerization. The hot cracked gases are then cooled, as, for examany liquid products of ple, in a condenser I24, and after separation of cracking, which separa-' tion takes place in a separator I26 having a liquid off-take I26, the cracked gases pass through a line I2T-having a valve I28 and a 5 pump or compressor I23 and by way of the line 35 to the absorber I of the gas-fractionating system 6.

Referring to Fig. 2, when products from the naphtha-reforming coil I06 are passed by way of the line I08 into the evaporator 3, gases from the separator 32 are preferably delivered to the scrubber I by reason of their relatively high content of gaseous oleflns. Where, however, products from the naphtha-reforming coil I06, together with products from the vapor-phase cracking coil 21, discharge into the evaporator 3', and the evaporator at 3 receives only the products from the coil I0, the gases liberated from the separator 32 will not contain unsaturates in as high a concentration, and in this instance these gases are preferably delivered by way of a line I30, wherein are located a valve I3I and a pump I32, to the line I20 to be introduced into the gas-cracking coil I23. The 20 cracked gases from coil I 23 may then be returned by way of lines I21 and 35 to the scrubber I for concentration as described.

'As has been indicated hereinabove, a crude distillation unit, a gas-cracking unit and a naphtha-reforming unit as illustrated in Fig. 2, or any of these, may be combined with a combination unit of the type illustrated in Fig. 1, thus the charge introduced at I0 in Fig. 1 may comprise reducedcrude withdrawn from an evaporator such as that illustrated in II in Fig. 2. Again, virgin gas oil such as that withdrawn at 63 in Fig. 2 maybe introduced into the vapor--' phase cracking coil 21 of Fig. 1, and the evaporator 3 of Fig. 1 may receive gas from a reform- 40 ing coil such as that illustrated at I06 in Fig. 2, and which may in turn receive virgin naphtha from a source such as the separator I02 01' Fig.

2. Furthermore, gases from a crude distillation unit such, for example, as those removed from the separator I02 of Fig. 2 may be introduced at 59 or 51 in the instance illustrated in Fig. 1 with or without cracking in a coil'such as that illustrated at I23 in Fig. 2.

It will be seen from the above that my invention provides for a polymerization of gases containing olefinic constituents as an adjunct to and a part of a cracking system of the so-called combination-unit type as defined hereinabove, wherein polymerization of the gases is effected in 55 such manner as to avoid the necessity for separate polymerizing equipment and without interference to the various oil-cracking operations carried out in the unit as a whole. The process of my invention has a further advantage in that it permits desirable cross-reactions to take place between the heavy oil undergoing cracking and the gas undergoing polymerization in the coil I6 and the recovery of the products in a simple and efficacious manner.

While I have described my' invention hereinabove with respect to various specific operating conditions and with reference to various typivarious types of apparatus for this purpose, it

will be understood by, those skilled in the art that my invention is not limited to such specific operative or illustrative details except insofar 15 r as such limitations are embodied in. the claims hereinafter made.

I claim:

1. In a process for converting hydrocarbon oil into relatively low-boiling hydrocarbon oil suitable for use as motor fuel in which a heavy hydrocarbon oil containing residual constituents is subjected to a mild cracking temperature under a high superatmospheric pressure, the products are fractionated to recover a clean condensate, said condensate is separately subjected to more drastic cracking conditions and the products are fractionated to separate gases, naphtha and heavier distillate, the improvements which comprise fractionating said gases to separate them into a lean fraction comprising principally hydrogen and methane and a rich fraction containing a relatively large amount of gaseous olefins, and commingling said rich fraction with the heavy hydrocarbon oil for subjection to said mild cracking temperature and said high superatmospheric pressure to eiTect a polymerization of gaseous olefins contained in said rich fraction to normally liquid products.

2. In a process for converting hydrocarbon oil into relatively low-boiling hydrocarbon oil suitable i'or use as motor fuel in which a heavy hydrocarbon oil containing residual constituents is subjected to a mild cracking temperature of from 800 to 900 F. under a pressure in excess of 500 pounds per square inch, the products are fractionated to recover a clean condensate, said condensate is separately subjected to a cracking temperature in excess of 900 F., and the products are fractionated to separate gases, naphtha and heavier distillate, the improvements which comprise fractionating said gases to separate them into a lean fraction comprising principally hydrogen and methane and a rich fraction containing a relatively large amount of gaseous olefins, and commingling said rich fraction with the heavy hydrocarbon oil for subjection to said temperature of from 800 to 900 F. and said pressure in' excess of 500 pounds per square inch to effect a polymerization of gaseous olefins contained in said rich fraction to normally liquid products.

3. In a process for converting hydrocarbon oil into relatively low-boiling hydrocarbon oil suitable for use as motor fuel in which a heavy hydrocarbon oil containing residual constituents is subjected in a first cracking stage to a mild cracking temperature under a high superatmospheric pressure, a clean condensate is subjected in a second cracking stage to more drastic cracking conditions, the products from said first and second cracking stages being delivered to a common evaporator and the vaporous-products from said evaporator being fractionated to separate gases, naphtha and heavier condensate, the-improve ments which comprise fractionating said gases to separate them into a lean fraction comprising principally hydrogen and methane and a rich fraction containing a relatively large amount of gaseous olefins, and commingling said rich fraction with the heavy hydrocarbon oil for subjection to "said mild cracking temperature and said high superatmospherie pressure to effect a polymerization of gaseous olefins contained in said rich fraction to normally liquid products.

4. In a process for converting hydrocarbon oil into relatively low-boiling hydrocarbon oil suitable for use as motor' fuel in which a heavy hydrocarbon oil containing residual constituents is subjected in a first cracking stage to a mild cracking temperature under a high superatmospheric pressure, the products are fractionated to recover a clean condensate, said condensate is separately subjected in a second cracking stage to more drastic cracking conditions and the prod-- 3 ucts are separately fractionated to separate gases, naphtha and heavier distillate, the improvements which comprise fractionating said gases to separate them into a lean fraction comprising principally hydrogen and methane and a rich frac- 10 tion containing a relatively large amount of gaseous olefins, and commingling said rich fraction with the heavy hydrocarbon oil for subjection to said mild cracking temperature and said high superatmospheric pressure to effect a polymeriza- 15 tion of gaseous olefins contained in said rich fraction to normally liquid products.

5. In a process for converting hydrocarbon oil into relatively low-boiling hydrocarbon oil suitable for use as motor fuel in which a heavy hydrono carbon oil containing residual constituentsis subjected in a first cracking stage to a mild cracking temperature under a high superatmospheric pressure, the products are fractionated to recover a clean condensate, naphtha and gases, said con- :5 densate is separately subjected in a second cracking stage to more drastic cracking conditions and the products are fractionated to separate gases, naphtha and heavier distillate, the improvements which comprise fractionating gases from said 30 first and second cracking stages to separate them into a lean fraction comprising principally hydrogen and methane and a rich fraction containing a relatively large amount of gaseous olefins, and commingling said rich fraction with the heavy as hydrocarbon oil for subjection to said mild cracking temperature and said high superatmospheric pressure to effect a polymerization of gaseous olefins contained in said'rich fraction to normally liquid products.

6. A process for converting hydrocarbon oil into relatively low-boiling hydrocarbon oil suitable for use as motor fuel which comprises distilling a crude petroleum to separate it into gas, naphtha, gas oil and residual constituents, subjecting said residual constituents to a mild cracking temperature under a high superatmospheric pressure, fractionating the products to recover naphtha and heavier clean condensate, commingling said gas oil and said clean condensate, separately subjecting them to more drastic cracking conditions and fractionating the products to separate cracked gases and distillate, fractionating said cracked gases. to separate them into a lean fraction comprising principally hydrogen 55 and methane and a rich fraction containing a relatively large amount of gaseous olefins, and commingling said rich fraction with said residual constituents for subjection to said mild cracking temperature and said high super-atmospheric o pressure to effect a polymerization of gaseous olefins contained in said rich fraction to normally liquid products.

7. A process for converting hydrocarbon oil into relatively low-boiling hydrocarbon oil suitable for 55 use -as motor fuel which comprises distilling a crude petroleum to. separate it into gas, virgin naphtha, gas oil and residual constituents, subjecting said residual constituents to a mild cracking temperature under a high superatmospheric (0 pressure, separately subjecting said virgin naphtha to a cracking temperature to effect a reformation thereof to naphtha of higher antiknock value and fractionating the reformed prodcracking operation to recover naphtha and heavier clean condensate, commingling said gas oil and said clean condensate, separately subjecting them to more drastic cracking conditions, and fractionating the products to separate cracked gases and distillate, fractionating said cracked gases to separate them into a. lean fraction comprising principally hydrogen and methane and a rich fraction containing a relatively large amount of gaseous olefins, and commingling said rich fraction with-said residual constituents for subjection to said mild cracking temperature and said high super-atmospheric pressure to effect a polymerization of gaseous olefins contained in said rich fraction to normally liquid products.

8. A process for converting hydrocarbon oil into relatively low-boiling hydrocarbon oil suitable for use as motor fuel which comprises distilling a crude petroleum to separate it into virgin gas, naphtha, gas oil and residual constituents, subjecting said residual constituents to a mild cracking temperature under a high superatmospheric pressure, fractionating the products to recover naphtha and heavierclean condensate, commingling said gas oil and said clean condensate,

separately subjecting them to more drastic cracking conditions, and i'ractionating the products to Separate incondensable gases and distillate, cracking said virgin gas to increase the olefin 'content thereof, commingling the thereby cracked gas with said incondensable gases, fractionating the commingled gases to separate them into a lean fraction comprising principally hydrogen and methane and a rich fraction containing a relatively large amount of gaseous oleflns, and commingling said rich fraction with said residual constituents for subjection to said mild cracking temperature and said high super-atmospheric pressure to eiiect a polymerization of gaseous olefins contained in said rich fraction to normally liquid products.

PIKE H. SULLIVAN.

DISCLAIM ER 2,017,874.Pilce H. Sullivan, New Rochelle, N. Y. TREATMENT or HYDROCARBONS.

Patent dated October 22, 1935. Disclaimer filed September 18, 1937, by the assignee, Gasoli'rw Products Company, Inc. Hereby enters this disclaimer to claims 1 3, and 5 0f the aforesaid Letters Patent.

[Oflicial Gazette October 12, 1937.]

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