US2115606A - Process for hydrocarbon oil conversion - Google Patents

Description

April 26, 1938. J, Q ALTHER 2,115,606

PROCESS FOR HYDROCARBON OIL CONVERSION Original Filed vApril 17, 1929 designed to accomplish the best results.

Patented Apr.`- 2b, 1938 PATENT OFFICE PROCESS FOR HYDROCARBON GIL CONVERSION Joseph G. Aimer. chicago, nl., assigner to Universal Oil Products Company, Chicago, Ill., a corporation of Delaware Original application April 17, 1929, Serial No. 355,704. Divided and this application June 27,

1936, Serial No. 87,689

14 Claims.

This is a division of my co-pending application Serial No. 355,704, iiled April 17, 1929, now Patent No. 2,091,261.

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

The utility of the invention as well as many o'b- `iects 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 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 unit. This is of particular importance in effecting the capacity and thermal eiliciency of the process.

Another purpose of the invention resides in the employment of means to increase the decomposition of both the vapors and liquid from the pressure expansion drum under controlled conditions This feature not only has an effect in increasing the yields of lighter hydrocarbons obtained from the operation but also in improving their quality, especially for use as a motor fuel, in that they will consist more largely of higher antiknock compounds.

Briefly, the process of as follows:

The charging stock plus reux will be pumped through a conventional furnace having a large heating surface from which the heated oil may the present invention is be transferred to a drum. This drum may be unheated but lagged against excessive radiation losses. Expansion takes place in the drum from which vapors may be withdrawn separately, passing preferably through a vapor heating coil to provide further conversion and into a zone of lower pressure into which residual oil from the expansion drum may be directed.

From this point on the usual operation takes place, i. e., all the vapors from the flashing still are directed to a dephlegmator where the sufficiently converted fractions are separated from the heavier ends (reflux) by the incoming cold raw oil or other cooling medium, said reflux being returned to the cracking coil for retreatment.

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 I and branch 2, having valve 3 into a heating coil 4, located in a furnace 5.

In heating coil 4 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 that degree of reaction at which formation oi coke and sludge-like matter occurs, or exceeds a predetermined desired degree.

Chamber I0 may take any desired form and size in relation to the capacity of the apparatus. It may be unheated and insulated against loss of -heat by radiation and may be maintained at a temperature not substantially higher than the temperature of the oil introduced thereto from heating coil 4 through line 6 and valve 1.

On the other hand, particularly for the -heavier charging stocks and depending upon the limitations imposed upon the amount of coke and sludge to be formed or contained in the products, it may be desirable to maintain the materials in chamber l0 at; a' temperature lower than that reached at the discharge of heating coil 4 to decrease the rate at which the reaction proceeds in chamber I0. To this end the oil may be cooled chamber l0 to ladditional heating at elevated tem-fl peratures to effect a controlled degree of sci-called vapor-phase cracking whereby I am enabled to produce lighter valuable distillates having the characteristics of motor fuels or gasoline, possessing high anti-knock properties due to the'presence of controlled proportions of, aromatic and unsaturated hydrocarbons formed by said vapor cracking. g

For this purpose a vapor coil 22 may be positioned in furnace 5 and located therein in such let a manner that the combustion gases pass over coil 22 before passing over coil 4. In this manner and because the combustion gases passing over coil 22 are at a higher temperature than when they pass over coil 4, a greater degree of radiant heat may be utilized in coil 22 than in coil 4. Coil 22 may be connected to vapor line I9 through branches 23 and 24, respectively, controlled by valves 25 and 26. By proper regulation of valves 26, 25, and 26, any desired amount of vapors separated in chamber I6 may be passed through the vapor heating coil 22. 'I'he vaporous products from line I9, including the heated products supplied thereto from coil 22 pass through line |66 into chamber 54 at any desired point in this zone by regulation of valves 51, preferably entering the lower portion of this zone and commingling therein with the liquid products sup-` plied, as will be later described, from chamber I6 to chamber 54, whereby to supply additional heat to said liquid products and assist their further vaporization.

The heavier liquid products are withdrawn from chamber I6, preferably from the bottom thereof, through line I having valve 52 and are directed to flash chamber 54 to be subjected therein to ash distillation to any desired degree. Chamber 54 is provided with a bottomdraw-off 6I, having valve 62, whereby liquid or semi-solid products may be removed therefrom. Solid matters formed in the operation of the process and deposited in chamber 54 may be removed therefrom through top and bottom manholes in the usual manner.

Raw oil to be treated in the process may be drawn from suitable storage tanks (not shown) through line 46 and pump 44. From'line 43 and by suitable control of the valves shown, all or a portion of the raw oil to be treated in the process may be diverted through line 45. having valve 46, then to line 41 which connects with the main feed line I, whereby all or a portion of the charging stock may be fed directly to the heating tubes.

Vapors separated by flash distillation in cham' ber 54 may be removed therefrom through line 66 having valve 61 to fractionating column 69, wherein they are subjected to controlled condensation by introducing into dephlegmator 69 suitable cooling medium through line 16 having valve 1I; or raw oil to be charged to the process may be diverted from line 46 through line 12, having valve 13 and introduced to column 69.

Vapors uncondensed in column 69 may be removed therefrom through upper draw-oil! line 14, having valve 15, and passed to condenser 16, thence to receiver 11, having usual gas release valve 16 and distillate release valve 19. The fractions of the vapors condensed in column 69 may be discharged from the bottom thereof throughv line 66, in which may be interposed pump 6I,v

from which they are directed through line 64,

Ahaving valve 65, lconnected with feed line 41,

be desirable to cool the vapors immediately after they are subjected to vapor-phase cracking in coil 22. Suitable lines and valves (not shown) may vbe provided whereby material passing through line 41 may be diverted and injected into line 24'through which the vapors leave coil 22. Line 90 controlled by valve 96 is also provided for introducing regulated quantities of the materials passing through line 41 into line I9 and provision is also made for diverting regulated quantities of oil from line I through line 61 and valve 61 into line 6.

A portion of the non-condensable gas from receiver 11 may be returned to vapor line I9 leaving reaction chamber I6 by means of valve 92 in line 93. This gas will pass through coil 22 together with the vapors from the reaction chamber or be by-passed through valve 26, depending upon the operation desired. In any event the uncondensed gas and vapors may be introduced into chamber 54 at any desired point in this zone and, in the event the liquid level in chamber 54 is above the point of introduction, the hot gas and vapors will act as a partial pressure agent to facilitate vaporization in this zone. By controlling the point of entry by means of valves 51, the vapors may enter flash chamber 54 either above or below the liquid level maintained therein. If full advantage of partial pressure eifect of these vapors is to be taken, they should enter at the lowest point in chamber 54 in order to increase vaporization and facilitate reduction of the percentage of unvaporized oil.

The valves and pumps shown permit the operator to maintain suitable pressures on the various parts of the apparatus. The flash chamber 54 and its connected parts such as dephlegmator 69, condenser 16 and receiver 11 are preferably maintained at a pressure substantially lower than the pressure maintained in chamber I6. Any suitable pressure may be maintained in vapor cracking 'coil 22 in relation to the pressure maintained in chamber I6. Heating coil 4 in chamber I6 may be maintained at substantially the same pressure or the pressure maintained in chamber I6 may be lower than that maintained in the heating coil although still substantially above atmospheric pressure.

As an illustration of the temperatures which may be maintained 'in an operation carried out in accordance with the invention, the oil may be heated in heating coil 4 to a temperature of, say 920 F.' to 960 F., said oil entering chamber I6 at a temperature near but relatively lower than said temperature. In chamber I6 the oil may be maintained at a temperature of, say 850 to 900 F. The vapors leaving chamber I6 and recycled gases from receiver 11 may be heated in vapor ,coil 22 to a temperature of approximately 975 to 1100 F. In this illustration a pressure of approximately 450 pounds may be maintained on heating coil 4.and chamber I6. The pressure may be reduced on flash chamber 54 down to approximately 25 pounds. The vapors leaving chamber I6 may be passed through vapor coil 22 under a pressure ofl approximately 100 pounds,

more or less.

It is to be understood that the preferred method of operation is of the low level type, wherein a minimum quantity of residual oil ismaintained in the chamber I6. That is, residual oil is withdrawn from chamber I6 before it has had sumcient time to form more than 5 per cent of sludge or coke-like constituents.

I claim as my invention:

1. In-a process wherein hydrocarbon oil charging stock is heated to a temperature sufficient to effect substantial vaporization thereof, its resulting vaporous and liquid components separated and the vapors supplied to a separate cracking zone wherein they are subjected to temperature and pressure conditions regulated to effect the production therefrom of high yields of good antiknock gasoline, the improvement which comprises commingling relatively hotconversion products from said cracking zone with said liquid components, whereby to effect appreciable further vaporization of the latter, removing'the remaining unvaporized residue from the system, subjecting the vaporous products including those resulting from further vaporization of said liquid components to fractionation for the formation of reflux condensate, subjecting fractionated vapors of the desired end-boiling point to condensation, separating the resulting distillate and uncondensed gases, recovering the distillate, and returning a portion of the uncondensed gases to said cracking zone and therein heating the same to an ofl cracking temperature together with said vaporous components supplied thereto.

2. In a process wherein hydrocarbon oil charging stock is heated to a temperature sufficient to effect substantial vaporization thereof, its resulting vaporous and liquid components separated and the vapors supplied to a separate cracking,

zone wherein they are subjected to temperature and pressure conditions regulated to effect the Y production therefrom of high yields of good antiknock gasoline, the improvement which comprises commingling the relatively hot conversion products from said cracking zone with said liquid components, whereby to effect appreciable i further vaporization of the latter, removing the remaining unvaporized residue from the system, subjecting the vaporous products, including those resulting from the further vaporization of said liquid components, to fractionation for the formation of reflux condensate, returning reflux condensate'formed by said fractionation to further treatment within the system, subjecting fractionated vapors of the desired end-boiling point to condensation, separating the resulting distillate and uncondensed gases, recovering the distillate and returning a portion of the uncondensed gases to said cracking zone and therein heating the same to an oil cracking temperature together with said vaporous components supplied products from said cracking zone with said liquid components, whereby to effect appreciable further vaporization of the latter, removing the remaining unvaporized residue from the system, subjecting the vaporous products. including those resulting from the further vaporization of said liquid components, to fractionation for the formation of reflux condensate, comminglfng reflux condensate formed by said fractionation with the `charging stock undergoing treatment in the first mentioned heating stage of the system, subjecting fractionated vapors of the desired end-boiling point to condensation, separating the resulting distillate and uncondensed gases, recovering the distillate and returning a portion of the uncondensed gases to said cracking zone and therein heating the same to an oil cracking temperature together with said vaporous components supplied thereto. l e

4. In a process wherein hydrocarbon oil charging stock is heated to a temperature sufficient to effect substantial vaporization thereof, its resulting vaporous and liquid components separated and the vapors supplied to a separate cracking zone wherein they are subjected to temperature and pressure conditions regulated to effect the production therefrom of high yields of good antiknock gasoline, the improvement which comprises commingling relatively hot conversion products from said cracking zone with said liquid components, whereby to effect appreciable further vaporization of the latter, removing the remaining unvaporized residue from the system, subjecting the vaporous products, including those resulting from the further vaporization of said liquid components, to fractionation for the formation of reflux condensate, subjecting fractionated vapors oi the desired end-boiling point to condensation, separating the resulting distillate and uncondensed gases, recovering the distillate, reheating a portion of the uncondensed gases to a high oil-cracking temperature and commingling the same directly and without substantial cooling thereof with said liquid components from the first-named heating stage.

5. In a process wherein hydrocarbon oil charging stock is heated to a temperature sufficient to effect substantial vaporization thereof, its resulting vaporousand liquid components separated and the vapors supplied to a separate cracking zone wherein they are subjected to temperature and pressure conditions regulated to effect the production therefrom of high yields of good antiknock gasoline, the improvement which comprises commingling relatively het conversion products from said cracking zone with said liquid components whereby to effect appreciable further vaporization of the latter, removing the remaining unvaporized residue from the system, subjecting the vaporous products, including those resulting from the further vaporization of said liquid components, to fractionation for the formation of reflux condensate, eommingling reflux condensate formed by said fractionation with the charging stock undergoing treatment in the first mentioned heating stage of the system. subjecting fractionated vapors of the desired endboiling point to condensation, separating the resulting distillate and uncondensed gases, recovering the distillate, reheating a portion of the uncondensed gases to a high oil-cracking temperature and commingling the same directly and without substantial cooling thereof with said liquid components from the first-named heating stage.

6. In a process wherein hydrocarbon oil charging stock is subjected to cracking temperature at substantial superatmospherfc pressure, the' resulting vaporous and liquid conversion products separated and the vapors subjected to appreciable additional conversion at increased temperature in a separate cracking zone, the improvement which comprises commingling the additionally cracked vapors, while still at a higher temperature than said liquid products, with the latter in a separate zone, whereby appreciable further vaporization of the liquid products` and appreciable cooling of the additionally cracked vapors is accomplished, subjecting the vaporous products from said separate zone to fractionation for the formation of reflux condensate, returning reilux condensate formed by said fractionation to the first mentioned cracking step, subjecting fractionated vapors of the desired end-boiling point to condensation, separating the resulting distillate and uncondensed gases, recovering the distillate and returning a portion of the uncondensed gases to the second mentioned cracking step and heating the same therein to said increased temperature together with the first-mentioned vapors. A

7. In a process wherein hydrocarbon oil charging stock is subjected to cracking temperature at substantial superatmospheric pressure, the resulting vaporous and liquid conversion products separated and the vapors subjected to appreciable additional conversion at increased temperature in a separate cracking zone, the improvement which comprises commingling the additionally cracked vapors, while still at a higher temperature than said liquid products, with the latter in a separate vaporizing zone, whereby appreciable further vaporization of the liquid products and appreciable cooling of the additionally cracked `vapors is accomplished, subjecting the vaporous products from said separate vaporizing zonek 'to fractionation for the formation of reflux condensate, returning reflux condensate formed by said fractionation to the first mentioned cracking step, subjecting fractionated vapors oi' the desired end-boiling point to condensation, separating the resulting distillate and uncondensed gases, recovering the distillate, reheating a portion of the uncondensed gases to a high oil-cracking temperature and introducing `the same directly and without substantial cooling thereof into said separate vaporizing zone.

8. In a process wherein hydrocarbon oil charging stock is subjected to cracking temperature at substantial superatmospheric pressure, the resulting vaporous and liquid conversion products separated and the vapors subjected to appreciable additional conversion at increased temperature in a separate cracking zone, the improvement which comprises commingling the additionally cracked vapors, while still at a higher temperature than said liquid products, with the latter in a separate zone, whereby appreciable further vaporization of the liquid products and appreciable cooling of the additionally cracked vapors is accomplishedl subjecting the vaporous products from said separate ione to fractionation for the formation of reflux condensate, returning .reflux condensate formed by said fractionation to the rst mentioned cracking step, subjecting fractionated vapors of the desired end-boiling point to condensation, separating the resulting distillate and uncondensed gases, recovering the distillate and returning a portion of the uncondensed gases to further treatment in the same cracking step to which said vaporous products are supplied and heating the same therein, to said increased temperature together with the first-mentioned vapors.

9. In a cracking process wherein hydrocarbon oil charging stock is subjected to cracking conditions in a heating coil. the resulting heated products introduced into a separating chamber wherein their vaporous and liquid components separate and from which they are separately removed, the vapors subjected to vapor-phase cracking conditions in a separate heating coil and supplied therefrom to a separate chamber wherein they are afforded additional conversion time, the improvement which comprises contacting relatively hot vapors resulting from said vapor-phase cracking with liquid conversion products withdrawn from said separating chamber, whereby to effect appreciable further vaporization of the latter, recovering the remaining unvaporized residue, subjecting the vaporous products, including those evolved from the liquid products by said further vaporization, 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 a portion of the latter to a relatively high temperature and introducing the reheated gases directly and Without substantial cooling thereof into said second mentioned chamber.

10. The improvement as defined in claim 9 further characterized in that said portion of the uncondensed gases is reheated in said separate coil in admixture with the first-named vapors.

11. A conversion process which comprises passing hydrocarbon oil through a heating coil and heating the same therein sufliciently to vaporize a substantial portion thereof, separting resultant vapors from unvaporized oil in an enlarged zone, removing the unvaporized oil and introducing the same into a second enlarged zone, removing vapors from the first-named enlarged zone and heating the same to vapor phase cracking temperature in a second heating coil, subsequently introducing the vapor phase cracked vapors into contact with the unvaporized oil in said second enlarged zone, removing admixed vapors and gases from the second enlarged zone and subjecting the same to condensation to separate vapors from gases, heating a portion of the separated uncondensed gases to a high oilcracking temperature and subsequently introducing the same directly and without substantial cooling thereof into contact with the unvaporized oil in said second enlarged zone.

12. The process as defined in claim 1l further characterized in that said portion of the gases f is heated in said second coil in admixture with the vapors being heated therein to vapor phase cracking temperature.

13. In a hydrocarbon oil conversion process wherein there is formed a mixture of vapors and gases which is fractionated and then subjected to final condensation and the incondensible gases separated from the final condensate, the method which comprises heating hydrocarbon oil to distillation temperature in a, heating coil and separating the same into vapors and unvaporized ol in a separating chamber, introducing the unvaporized oil into a second chamber maintained under lower pressure than the first-named chamber, simultaneously heating vapors from the firstnamed chamber and a portion of said incondensible gases to a high oil-cracking temperature, introducing the thus heated vapors and gases into contact with the unvaporized oil in said second chamber, and supplying admixed vapors and gases from the second chamber to said fractionating step. v

14. In a hydrocarbon oil conversion process wherein there is formed a mixture of vapors and aumcoe gases which is fractionated and then subjected to inal condensation and the incondensible gases separated from the nal condensate, the method which comprises heating hydrocarbon oil to dising vapors from the first-named chamber and a portion of said incondensible gases to a high oil-cracking temperature, introducing the"`thus heated vapors and gases into the lower portion .of the second chamber` to ow in countercurrent contact with said unvaporized oil, and supplying admixed vapors and gases from the second chamber to said fractionating step.

JOSEPH G. ALTHER.

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