US2158812A - Process for hydrocarbon oil - Google Patents

Description

May 15, 1939. J. G. ALTHER 2,158,812

PROCESS FOR HYDROCARBON OIL CONVERSION Filed Nov. 50, 1936 Patented May 16, 1939 FATEN' OFFME PROCESS FORl HYDROCARBON OIL CONVERSION Joseph G. Alther, Chicago, Ill., assigner to Universal Oil Products Company, Chicago, Ill., a` corporation of Delaware Application November 30, 1936, Serial No. 113,430

9 Ciaims.

This application is a continuation-in-part of my co-pending application Serial No. 355,704, led April 17, 1929, now Patent No. 2,091,261.

The invention relates to improvements in process for hydrocarbon oil conversion, and refers more particularly to improvements designed for the elicient cracking of hydrocarbon oils to convert and produce therefrom products having higher commercial value.

The utility of the invention as well as many objects and advantages thereof will be brought out in the following description.

The principal object of the invention is to subject hydrocarbon oil to such conditions of temperature and pressure as to produce maximum yields of lighter gravity products suitable for use as motor fuel with a minimum coke and gas loss.

Another object is to carry out the operation in such manner as to cause the non-vaporous residue to accumulate in a low pressure zone.

Another object is to provide for lowering the reflux ratio by making it possible to convert a greater proportion of the higher boiling point hydrocarbons per pass through the stock. This is of particular importance in effecting the capacity and thermal efficiency of the process.

Another purpose of the invention resides in the employment of means to increase the decomposition oi vapors from the pressure expansion` drum under controlled conditions designed to accomplish the best results. This feature not only has an effect in increasing the yields of lighter hydrocarbons contained from the operation but also in improving their quality, esp.,- cially for use as a motor fuel, in that they will consist more largely of higher anti-knock compounds.

In order to more clearly understand the invention, I have shown the accompanying drawing, which is a diagrammatic view, but not to scale, of an apparatus suitable for carrying out the invention,

Referring to the drawing and to the operation of the invention, `the oil to be treated is directed through line l and branch 2, having valve 3 into a heating coil 4, located in` a furnace 5.

In heating coil Il the oil is heated to a temperature within the cracking range under a suitable pressure. The amount of oil passed through the coil per unit time, and the size of the apparatus are so correlated that under the temperatures and pressures used the degree of cracking obtained in the heating coil is preferably short of thatfdegreeof reaction at which formation (Cl. 19E- 60) of coke and sludge-like matter occurs, or exceeds a predetermined desired degree.

The heated products are discharged from heating coil 4 through line 6 and valve 'l into chamcalled vapor-phase cracking, whereby I am enabled to produce lighter valuable distillates having the characteristics of gasoline and possessing high antiknock properties due to the presence oi aromatic and-unsaturated hydrocarbons .f formed by the vapor-phase cracking. For this purpose a vapor-coil 22 may be positioned in furnace 5 and located therein in such a manner that a greater degree oi radiant heat may be utilized in coil 22 and in coil 4. Coil 22 may be connected to vapor-line i9 through line 23 controlled by valve 25. In my companion application, Serial No. 113,428, filed on even date herewith, I have disclosed and claimed a modification of the present process wherein fresh charging stock is introduced to the separating chamber and vaporized at least in part therein, the charging oil vapors being also supplied to the Y vapor heating coil. The heated products are discharged from coil 22 through line 2li, valve 26 and line lii into chamber 54, entering this zone at any desired point or plurality of points therein by regulation of valves 5l. Preferably, as indicated in the drawing, these products enter the lower portion of chamber 55 and pass upwardly therethrough whereby their vaporous components are subjected to appreciable continued conversion time therein.

Liquid components of the heated products supplied, as previously described, to chamber Il), are separated therein from their vaporous components and the liquids are withdrawn from chamber ill through line el and valve 53 and directed into chamber 5@ wherein they are heated and subjected to appreciable further vaporization by comminglng therein with the more highly heated products from heating coil In my companion application, Serial No. 113,429, iiled on even date herewith, I have disclosed and claimed a modication of the present process wherein` the liquid oil from chamber lil is heated to cracking temperature in an independent heating coil prior to introduction to chamber 54.

Chamber 54 is provided with a draw-off line SI having valve 62 whereby liquid or semi-liquid e products remaining unvaporized in this zone may be withdrawn therefrom to cooling and storage or elsewhere, as desired. Or the liquid products may be distilled to dry coke in chamber 54 as claimed in my companion application, Serial No. 113,427, iiled on even date herewith.

Vaporous products may be directed from chamber 54 through line 66 and valve 6T to fractionation in column 69 wherein their fractionation may be assisted by the introduction of a suitable reuxing and cooling medium through line 10 and valve ll and/or by the introduction of a regulated quantity or all of the charging stock into fractionator 69, as will be later described.

Vapors uncondensed in column 69 may be removed therefrom through line 'I4 and valve 'I5 and passed through condenser 16 to receiver 'I1 having the usual gas release valve 18 and distillate release valve 19.

A portion of the uncondensed gases from receiver 'Il may be returned to vapor line I9 leaving chamber l0, by means of line 53, pump or compressor 94, and valve 92. This gas will pass through coil 22, together with the vapors from chamber l0, and be directed therewith, in the manner previously described, into chamber 54, wherein they serve to facilitate conversion.

Raw oil to be treated in the process may be drawn from suitable storage tanks (not shown) through line 43 and pump 44 from which all or a portion of the raw oil may be directed through line 45, valve 46 and line 4l which connects with the main feed line I, whereby all or a portion of the charging stock may be fed directly to heating coil 4 or a portion or all of this material may be directed through line 12 and valve I3 into fractionator G9, as previously mentioned.

Reiiux condensate formed in fractionator 69 comprises components of the vaporous products supplied to this zone, as previously described, which are condensed in this zone, as well as the total or high-boiling fractions of any charging stock supplied thereto, in the manner described. The reflux is withdrawn from the lower portion of column 69 and directed through line 80 to pump 8l wherefrom it is directed through line 84 and valve 85 into line 41 and thence to further cracking in heating coil 4.

The preferred range of operating conditions which may be employed to accomplish the objects of the present invention in an apparatus such as illustrated and above described, may be approximately as follows: The temperature ernployed at the outlet from heating coil 4 may range, for example, from 800 to 950 F., or thereabouts, preferably with a superatmospheric pressure at this point in the system, ranging from to 500 pounds, or more, per square inch. The pressure maintained in chamber Il! may be substantially the same or lower than that maintained at the outlet from the preceding heating coil and preferably a sumcient superatmospheric pressure is maintained in chamber lll to eifect the passage of the vaporous products from this zone through heating coil 22 without the aid of a pump or compressor and to maintain the desired pressure at the outlet from heating coil 22, which latter may range, for example, from substantially atmospheric to a superatmospheric pressure of pounds, or more, per square inch, a relatively low superatmospheric pressure of the order of 100 pounds, or less, being preferred in this zone. The temperaure maintained at the outlet from heating coil 22 may range, for example, from 950 to 1100" F., or thereabouts. Chamber 54 may be operated at substantially the same or at a lower pressure than that maintained at the outlet from heating coil 22 and the pressure maintained in the succeeding fractionating, condensing and collecting portions of the system may be substantially the same or lower than the pressure employed in chamber 54.

As a specific example of the operation of the process as it may be conducted in an apparatus of the character illustrated and above described, the charging stock is a crude oil of about 35 A. P. I. gravity containing some 30 per cent of material boiling up to 400 F. which is a poor antiknock value. The charging stock is supplied, together with reflux condensate from the fractionator, to the first cracking coil wherein it is heated to an outlet temperature of approximately 900 F. at a superatmospheric pressure of about 300 pounds per square inch, the heated products are supplied to a vaporizing and separating chamber which is maintained at a superatmospheric pressure of approximately 100 pounds per square inch and wherefrom the resultant vaporous and liquid products are separately removed. The vaporous products are passed at approximately the same pressure as that maintained in the Vaporizing and separating chamber through a vaporphase heating coil wherein they are heated to an outlet temperature of approximately 1000z F. and thence introduced into a reaction chamber wherein they are afforded additional conversion time and commingled with liquid products supplied to this Zone from the rst mentioned chamber, serving to reduce the latter to coke in this zone. The vaporous products from the reaction chamber are subjected to fractionation for the formation of said reflux condensate which is returned to the first mentioned heating coil. Fractionated vapors of the desired end-boiling point comprising materials within the boiling range of gasoline and fixed gases are subjected to condensation, the resulting distillate and uncondensed gases collected and separated and a regulated portion of the latter returned to the vapor-phase heating coil. This operation will produce, per barrel of charging stock, approximately '73 per cent of cracked gasoline of about 400 F. end-boiling point, having an octane number of over '70 by the motor method, the remainder being chargeable, principally, to coke, gas and loss.

I claim as my invention:

1. In a process wherein hydrocarbon oil is heated to cracking temperature in a heating coil, resultant heated products introduced into a separating chamber wherein vaporous and liquid components thereof. separate and from which they are separately removed, and vaporous components removed from the chamber heated to vapor-phase cracking conditions in a separate heating coil and supplied therefrom to a separate chamber, the improvement which comprises contactlng the reheated vapors with liquid conversion products Withdrawn from said separating chamber whereby to effect appreciable further vaporization of the latter, subjecting the resultant vapors to fractionation, supplying reflux condensate formed by said fractionation to the first mentioned cracking operation, subjecting fractionated vapors of the desired end-boiling point to condensation, recovering and separating the resulting distillate and uncondensed gases, reheating regulated quantities of the latter to an oil cracking temperature and introducing the same into said separate chamber.

2. In a process wherein hydrocarbon oil is heated to cracking temperature in a heating coil, resultant heated products introduced into a separating chamber wherein vaporous and liquid components thereof separate and from which they are separately removed, said vaporous components heated to vapor-phase cracking conditions in a separate heating coil and supplied therefrom to a separate chamber, the improvement which comprises contacting the reheated vapors with liquid conversion products withdrawn from said separating chamber whereby to effect appreciable further vaporization of the latter, subjecting the resultant vapors to fractionation, supplying reflux condensate formed by said fractionation to the first mentioned cracking operation, subjecting fractionated vapors of the desired end-boiling point to condensation, recovering and separating the resulting distillate and uncondensed gases, reheating regulated quantities of the latter to an oil cracking temperature and introducing the same into said separate chamber, together With said reheated vapors.

3. In a process wherein hydrocarbon oil is heated to a cracking temperature in a heating coil, resultant heated products introduced into a vaporizing and separating chamber wherein vaporous and liquid components thereof separate and from which they are separately removed, and vaporous components removed from the chamber heated to vapor-phase cracking temperature in a separate heating coil and supplied therefrom to a separate chamber, the improvement Which comprises commingling vaporous products discharged from the last mentioned heating coil with liquid conversion products Withdrawn from said separating chamber whereby to effect appreciable further vaporization of the latter, subjecting the resultant vapors to fractionation, supplying reflux condensate supplied by said fractionation to the first mentioned heating coil for further cracking, subjecting fractionated vapors of the desired endboiling point to condensation, recovering and separating the resulting distillate and uncondensed gases, reheating regulated quantities of the latter to an oil cracking temperature and maintaining the reheated gases in commingled state with said vaporous components during subjection of the latter to said vapor-phase cracking.

4. A conversion process which comprises. heating hydrocarbon oil to cracking temperature under pressure in a heating coil and separating resultant vapors and unvaporized oil in an enlarged chamber, removing vapors from the chamber and heating the same to vapor phase cracking temperature in a second coil, separately' removing unvaporized oil from the chamber and contacting the same with the heated products from said second coil to vaporize a substantial portion of the unvaporized oil, fractionating the vapors from this contacting step and supplying resultant reflux condensate to the rstnamed coil, finally condensing the fractionated vapors and separating the final condensate from normally incondensible gases produced in the process, reheating at least a portion of the separated gases to a temperature at least as high as said vapor phase cracking temperature and introducing the reheated gases into contact with said unvaporized oil removed from the chamber.

5. The process as defined in claim 4 further characterized in that said separated gases are reheated in said second coil together with the vapors supplied to this coil from said chamber.

6. A conversion process which comprises heating hydrocarbon oil to cracking temperature under pressure in a heating coil and separating resultant vapors and unvaporized oil in an enlarged chamber, removing vapors from the chamber and heating the same to vapor phase cracking temperature in a second coil, separately removing unvaporized oil from the chamber and introducing the same to a. reduced pressure vaporizer, discharging the heated products from said second coil into said vaporizer, fractionating the vapors from the vaporizer and supplying a resultant reflux condensate to the first-named coil, finally condensing the fractionated vapors and separating the final condensate from normally incondensible gases produced in the process, reheating at least a portion of the separated gases to a temperature at least as high as said vapor phase cracking temperature and introducing the reheated gases into said vaporizer.

7. The process as defined in claim 6 further characterized in that said separated gases are reheated in said second coil together with the vapors supplied to this coil from said chamber.

8. A conversion process which comprises heating hydrocarbon oil to cracking temperature under pressure in a heating coil and thence discharging the same into an enlarged chamber, removing vapors and unvaporized oil from the chamber and introducing the unvaporized oil to a vaporizer, passing hydrocarbons removed as vapor from the enlarged chamber through a second heating coil and heating the same therein to higher cracking temperature than the oil in the first-named coil, discharging the heated products from said second coil into said vaporizer, fractionating the vapors from the vaporizer and supplying resultant reflux condensate to the first-named coil, nally condensing the fractionated vapors and separating the inal condensate from normally incondensible gases produced in the process, reheating at least a portion of the gases to a higher temperature than that to which the oil is heated in the first-named coil, and introducing the reheated gases into said vaporizer.

9. The process as defined in claim 8 further characterized in that said separated gases are reheated in said second coil.

JOSEPH G. ALTHER.

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