US1752264A - Manufacture of high-compression automotive distillate - Google Patents

Description

'c. J. PRATT 2, MANUFACTURE OF HIGH COMPRESSIQN AUTOMOTIVE DISTILLATE March 25, 1930.

Filed July 13, 1927 )INVENTOR.

Patented Mar. 25, 1930 UNITED STATES PATENT OFFICE cnm'ron JOHN rnnrr, or sr. tours, mssounr OI. HIGH-COMPRESSION A'UTOMOTIVE DISTILLATE Application filed July 13, 1927. Serial in. 205,288.

apparatus for the conversion of a liquid hy- 1 drocarbon series having a given fractional gravity distillation range into a liquid hydrocarbon series having a different fractional gravity distillation range; the provision of means for converting crude oil, or any fraction made therefrom into the maximum amount of automotive distillate resembling the present United States Motor Specification asoline with the admixture of not less than orty pprcent (40%) of coal tar benzol; and

the prov1sion of-means of the class described which produces-a minimum amount of residual oil, coke and gas. H 1 v One of the salient objects'of-the invention is to accomplish the desired conversion at substantially atmospheric pressure within the system, thereby eliminating .many undesirablefeatures of previous systems.v

Another object of the invention is to man- I ufacture an automotive distillate containing the maximum amount of anti-knocklproperties commercially obtainable from the hydrocarbons undergoing conversion. Other objects will be in part obvious and in part pointed out hereinafter.

The invention accordingly comprises the elements and combination of elements, features of construction, and arrangements of parts which will be exemplified in the structure hereinafter described, and the scope of the application of-which will be indicated in the-following claims.

In the accompanying drawing, in which is illustrated one of various possible embodiments of the invention, the figureillustrates" diagrammatically. the relationship between the elementso'f the system.

Corresponding reference characters indi-' cate corresponding parts throughout the single view of the drawing. 1

Referrin now more articularly to the drawing, t e indicia A ustrates a supply tank containing any liquid hydrocarbon whlch may be crude petroleum or any trac tion made therefrom. Numeral 1 illustrates ea suction line on which is located valve 2 through which the liquid hydrocarbon, hereafter referred .to asoil, is delivered to suc-.

tion side of pump 3. The oil is discharged through line 4: and such quantity as desired is delivered by a regulatingv valve 5 in line 4 6 into a cooling coil 7, located inside a dephlegmator B. The oil passing through coil 7 absorbs heat from certain vapors (to'be de-' I scribed) in dephlegmator B and passes from v the dephlegmator to a common header line j through coil outlet line 8.. I By manipulating the regulating valve 9,. any desired quantity of oil may be admitted from pump discharge line 4 through line 10 into a cooling coil 11 located in a lower oil reservoir section B of the'dephlegmator B.

By regulating a valve 12 in theline 13, any desired quantity of the oil passing out of coil 11 may be admitted to a'common header to a furnace heating coil 17. By regulating valve 1.4 an desired quantity of oil may be returne through-line 15'to supply tank A.

It is to be understood that there is a possibility that an excess amount of oil will necessarily be pumped through coil 11 above the required amount to be fed to the system in addition to the oil fed to the system through coil 7. This ,excess amount can be returned direct through line 15 to supply tank" A or it could, if desired, be made to pass through a coolin coil before returning to the supply tank y J Line 16 is'a common header through which oil is delivered from lines 8 and 13-to heating coil 17, located in preheating furnace O. Valve 18 is located at the outlet 'ofcoil 17 and is used, if necessary, to. prevent the oil being deliveredunder substantial pressure through line 19 into the expansion chamber D. The purpose of this is .to prevent pressure from building up in the expansion chamber D.

The vapors from expansion chamber D leave the vessel at a point near the top through va or line 20, which terminates as a reboiling 001121, near the bottom of the upper fractionv ating section S of dephlegmator B. The ob- 1 drawn through line 22 and delivered to .a cooling coil 23, submerged in water contained in cooling box E. A valve 24 at the outlet of the cooling coil regulates the liquid level in expansion chamber D and delivers the desired amount of oil to be withdrawn from the system through line 25 to a suitable storage tank, not shown on the drawing.

It is to be understood that this residual oil may gravitate to storage or may be withdrawn by means of a pump.

Inside the dephlegmator B in the top of the fractionating section S of the vessel, located below cooling coil 7 and above the re-boiler coil 21, are located a plurality of battle plates 26, which may be of any desired type to provide intimate contact between liquid and vapors undergoing treatment.

Numeral 27 illustrates a'diaphra m separating the upper fractionating section from the lower oil reservoir section of dephlegmator B. Numeral 28 illustrates an overflow nozzle adapted to maintain a liquid level in the upper fractionating section S. It is to be understood that this nozzle may extend, if desired, above or into the re-boiler coil 21 (see for example the dotted lines).

It is to be understood that the dephle mator B may be divided into a plurality of ractionating and reservoir sections, or the dephlegmator may be composed of several separate fractionating and dephlegmator sections with proper outside connections to insure the correct functioning of the apparatus. In other words, the fractionating section S and the reservoir section R may be formed as separate units, properly interconnected by suitable lines.

The liquid reservoir section B of dephlegmator B is cooled to any desired degree above atmospheric b the oil passing through coil 11. The coole oil in reservoir B provides the precracked chargin' stock, which is withdrawn through suction line 29 by means of pump 30 and is discharged through line 31 to a heating coil 32 of small cross-sectional area in a cracking furnace F. Substantially atmospheric pressure is used in the coil 32; that is, the pressure is'substantially only that necessary to overcome the frictional resistance of the coil.

A valve 33 located at the outlet of heating 'coil 32, can he used if necessary to prevent cracked oil being'delivered under pressure through line 34 into a heat exchanger coil 35, located at a point near the bottom of the expansion chamber-D. The object of this exchanger coil 35 is to reboil all light distillates from the residual oil in the bottom of expansion chamber and at the Sametime reduce the temperature of the oil entering the expansion chamber from the cracking furnace coil. Anotherpurpose of'this is to prevent coking.

A plurality of bafile plates 36 are placed inside the expansion chamber above exchangbr coil 35 in order to provide intimate contact between the liquid and vapors discharged through line 19 and the vapors discharged from exchanger '35. It is to be understood that the heavy vapors discharged into ex-. pansion cham er from line 19 will absorb a certain amount of the lighter vapors delivered to the expansion chamber conditioner from coil 35.

It can be seen that the vapors from both precracking coils 17 and treating coil 32 blend and pass out of the expansion chamber 'D through the line 20, terminating in coil 21 into fractionating section of dephlegmator B. It is a function of the fractionating section of dephlegmator B to separate out the desired fraction of oil vapors for automotive consumption which leave the dephlegmator through vapor line 37 at a point near the top. These vapors pass through condenser coil 38,

submerged in water contained in condenser box G. The condensed vapors and non-con-' densable gas pass out through line 39 into gas separator H-on which is located liquid level gauge 40. The non-condensable gas is Withdrawn through line 41 ata point near the top of gas separator H by means of pump or blower 42, which discharges the non-condensabl-gas through line 43 either to an absorption plant for the further recovery of automotive distillate or the non-condensable gas.

may be used as fuel, for the furnaces F and C.

By opening valve 4 1 automotive distillatemay be withdrawn from the bottom of gas separator H and delivered to a suitable storage tank (not shown) through line 45. It is to be understood that the automotive distillate may either gravitate to storage or may be withdrawn by means ,of a pump.

Numerals 46 and 16 represent fuel burners of a conventional type, which supply the products for combustion to preheating and cracking furnace C and F, respectively.

Flanged. manholes 47 and 47 on expansion chamber D and flanged manholes 48 and 48' on dephlegmator B provide a means of cleaning and repairing the interior of either vessel.

The charging stock supply tank A will be substantially at atmospheric temperature. The charging stock after passing through the cooling coil 7 and 11, enters coil 17 in the preheating furnace at a temperature of the orderof 400 Fahrenheit, which is low enough to' prevent substantial coking. The temperature of the oil entering the preconditioner through line' 19 isof the order of 800 Fahrenheit.

'The cooled charging stockfrom the lower reservoir section B of dephlegmator B entemperature of the order of 250 Fahrenheit and leaves the cracking coil through line 34 at a temperature above 1100 Fahrenheit. The vapors from expansion chamber D admitted to dephlegmator B through vapor line 20, enters the dephlegmator at a temperature .not to exceed 800 Fahrenheit. The vapors leaving the de-phlegmator 'through line 37,

when preparing the end-point distillate for the-market should register a temperature of not more than 410 Fahrenheit. The gravity,

rather than the temperature, will determine the'quantity of residuum to be withdrawn from the expansion chamber through line 22;

' With the proper velocities through the heating coils the above conditions will treat the oil in the desired manner without the accumulation ofan appreciable amount of carbon within the system and with the production of the least possible amount of non-condensable gas.

The temperature in the preheating furnace C is low enough to prevent coking of the crude oil, which tends to coke at lower temperatures than the recycled or precracked stock. Conversely,'. the .precracked stock,

' from which the residuums andIcoke-forming constituents have been removed in the expansion chamber D, are subjected to a hightained.

er temperature in the cracking coil 32 without coking therein. The crackedvapors from the coil 32 can be brought to a temperature such that they will, upon contacting with the films of preheated crudes in the vaporizing chamber D, crack and further vaporize said preheated crudes, leavingas a liquid in said chamber D the residuums and coke-forming constituents. By the term coke-forming constituents herein is meant such .heavier fractions or residuums or the like of the crude oil or charging stock as are adapted to coke under the high temperature cracking operation described. The point is that the crude stock and recycled or pre cracked stock are each made'to pass through regions at differ- From the crudes, there-Y fore, in the vaporizing chamber D is formed ent temperatures.

a recracked stock, devoid of residuums and co :e-forming constituents, which is subsequently subjected to high temperature crack -w ing without 0 casioning coke formation in the high tempe ature still or cracking furnace F.

It will be seen from the above that the above process involves two heating stages whereby coking is prevented and consequent ly time saved. Furthermore, excessive gas production is prevented by absorption. Another point is that the product is blended hot and in the vapor stage. I

In view of the above, it will be seen that the several objects. of the .invention are achieved and other advantageous results at- As many changes could be made-incarrying out the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as -illustrative and not in a limiting sense.

I claim:

1. The process of treating hydrocarbons which comprises preheating said hydrocarbons to a temperature insufficient to coke the heavier constituents thereof, subjecting said preheated hydrocarbons to intimate contact with'cracked vapors ofrecycled hydrocarbons whereby said preheated hydrocarbons are va-. porized and partially cracked, and the coke- -forming constituents of said preheated hydrocarbons are removed therefrom as liquids, comingling the vapors generated from said preheated hydrocarbons and said cracked vapors of recycled hydrocarbons, separating said comingled vapors into lighter constituents and heavier constituents, subjecting said heavier constituents, to a vapor phase crack:

ing operation in a stream of restricted crosssectional area at substantially atmospheric pressure, and recycling said cracked vapors into indirect heat-exchange relationship with said heavier, coke-forming constituents of.

said. preheated original hydrocarbons, and .then nto intimate contact with said preheated original hydrocarbons.

2. The process of treating hydrocarbonmately contacting the same with cracked oil .vapors to form precracked vapors, partially condensing said precracked vapors to a precracked' oil, sub ecting said pre-cracked oil to a vaporphase cracking operation without substantial coke formation, and bringing the cracked vapors into contact with said preheated oil to crack said preheatedbil, and

removing light cracked hydrocarbon vapors and condensing the same.

3. The process of treating hydrocarbon oils which comprises subjecting said hydrocarbon oil to a reliminary cracking operat1on whereby co e-forming constituents are removed therefrom in liquid form, said cracking operation being conducted at substantially atmospheric pressure, said cracking operation being effected by filming said hydrocar .bon oil and intimately contacting the same with cracked oil vapors to form precracked vapors, partially condensing theprecracked vapors to a precracked oil, maintaining said precracked vapors and at leastpart of said p precracked oil in indirect heat-exchange re lationship,subjecti ng said precracked oil to 4- mower a vapor phase cracking operation Without substantial coke formation, and bringing the cracked vapors into contact with said hydrocarbon oil to crack said hydrocarbon oil, and removin 1i ht cracked hydrocarbon vapors and con ensmg the same.

In testimony whereof, I have signed' my vname to this specification this 11th day of Ju1 ,;92?. I i

GLIFTQN JoHN PRATT.

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