US1585233A - Process for continuously distilling and cracking hydrocarbon oils - Google Patents

Description

Jv W. COAST, JR

May 1s 1926. 1,585,233

PROCESS FOR CONTINUOUSLY DISTILLING AND CRACKING HYDROCARBON OILS duly 14, 1919 2 Sheets-Sheet l I 1 I I 1 60/12 .Setizpng Pa 2- I five/afar- Ja/m I44 (maid/r May 18,1926. v 1 ,585,233 J. W. COAST, JR PROCESS F01 CONTINUOUSLY DISTILLING AND CRACKING HYDROCARBON OILS Filed July 14; 1919 2 Sheets-Sheet 2 [Hue/afar Ja/m 144 60463 J? m uffl Patented May 18, 1.926

UNITED, STATE DOHERTY RESEARCH COMPANY, OF NEW YORK, N. Y., A GORZPORATIiQN OF'DELA- PATENT ounce.

7 JOHN w. coas r, an, or TULSA, OKLAHOMA, AssreNomBY mnsmi ASSIGNMENTS, r0

rnocnss FOR com'muous'LY pIsTILLINeAND CRACKING HYnRooA aBoN orns.

. Application filed July 14, 1919. Serial No. 310,856.-

My invention relates generally to the art of distilling liquids and more particu-larly to improvements in the treatment by destructive distillation or cracking of relatively heavy or high boiling point hydrocarbon oils for the purpose ofproducing therefrom lighter or lower boiling point products.

The principal objects of my invention are, to provide a relatively simple method or process which can be practiced continuously, thereby minimizing the time, labor and heating expense ordinarily involved in the production of lowboiling point products; to

provide for the rapid and continuous elimi-.

nation from the material under treatment,

' of the residue or pressure still bottoms utilized in practicing a modification of my improved method.- i

which, it will be understood, consists principally of carbon and heavy tar; further, to provide an improved method wherein the oil under treatment is expanded or the pressure in thesystem isreduced to effect adistil'lation of the lighter fractions from the pressure tar passing from the still in the system and causing the heavy coke, carbon and the like from the hydrocarbon to gravi tate to the bottom of a settling tank from whence they are eliminated and the lighter fractions thus produced returned to the still for further cracking; further,to provide a process whereln the reflux condensate is in direct contact with the heated vapors arising from the still, thereby vmaterially raising the temperature of 'said reflux. condensate, and further to-utilize the heat from certain of the intermediate boiling point products taken o'fl fromthe body of oil under treatment. and the heatfrom the residuum from the body of oil undertreatment'to preheat the fresh supply-of crude oil that is being delivered to the body ofoil under treatment.

A relatively simple apparatus for practicing my improved'method is illustrated in the accompanying drawings, in .Which Figure 1.is a diagrammatic view of the apparatus, parts thereof being in section- Figure 2 is a diagrammatic View of an apparatus which may "be advantageously ing drawings, 10 designates "a boiler -like container for the liquid under treatment,

said container being usually referred to as a still. This container or still is, disposed above a fire chamber 11 heated in any suitable manner and provided with an arch- 12 which directs the greater portion of the heat the still.

.By thus delivering the greatest heat to the within the chamber to the rear portion of rearportion of the still, the liquid Within the latter is caused to circulate along the tioned in the lower portion of the still. This I scraper comprises one or more'endless members 13, operating on sprocket wheels. 14 or the like, and said endless members carrying scraping devices 15- which are adapted to make direct contact with the inner surface of the bottom of the still so as to scrape and 1 move the coke and relatively heavy residue toward the rear end of said still;

- The preferred form of scraper utilized in the stilli's disclosed in my copending application, Serial Number 421494, filed Nov. 3,

A. coke and residue discharge pipe 16 leads from the lower portion of the rear end of the still to the lower portion of a coke pot .of an upright cylinder or container having a pressure equalizing piped-6. Located adjacent to the coke pot17 is an expansion drum 19 provided near its upper portion -17, the latter being preferably in the form with a vertically disposed baflle plate 20 and f leading from the upper portion of the. coke pot to the upper portion-of this'expansion drum is;a tubular connection 21 in which is located a pressure control valve 22. Located adjacent to the. expansion drum-is-an exchanger 23- and leading to a coil 24 in the upper portion thereof from the upper, portion of expansion drum 19 isa tubular connection 25. Located in the lower-portion of the exchanger is a coil 26 and leading'fronr -Referring by numerals to theaccompany- J the lower portion of expansion jdrum' 19 to tion 37 and leading from said pump to the upper portion of an exchanger 137 is a tubular connect-ion 38, the latter being provided with a suitable valve 39 adjacent to said last mentioned exchanger. .This exchanger 137 is connected to and projects upwardly from the still 10 and mounted on top of said exchanger is a reflux air cooled condenser 40 of suitable construction. Leading from tubular connection 38 to still 10 is a branch pipe 41 in whichis located a valve 42. Leading from reflux condenser 40 to a main con denser 43 is a tubular connection 44 which serves as a vapor line, and arranged therein is a suitable valve 45. Leading from the lower port-ion of the coil of the main condenser 43 to the tank 32 is a tubular connection 46. Leading from a suitable source of crude oil supply to the lower portion of exchanger 23 is a supply pipe 47.

In practicing my improved method with the apparatus above described, the oil to be treated is delivered to exchanger 23' through supply pipe 47 and rising in said exchanger absorbs heat from the heated residuum passing through coil 26 and which latter is located in the line from expansion drum 19 to receiving tank 28. This crude oil also absorbs heat from the expanded hydrocarbon vapors liquefying in coil 24 and the liquetied vapors discharging from the end of this coil mix With the crude oil rising through exchanger 23. The heated crude oil or mixture from exchanger tank 23 is drawn through line 37 by pump 36 and forced through line 38 either into exchanger 137 or directly into still 10 through branch pipe 41.

Obviously, the delivery of this crude oil mixture to exchanger 137 or still 10 is controlled by manipulation of valves 39 and 42. The heating of still 10 is governed by the requirements of the product being treated, and, as heretofore stated, the heat ispreferably delivered to the rear portion of the still in order to induce circulation of the liquid product along the bottom of the still toward the coke discharge pipe 16, and this circulation is materially assisted by the action of the endless scraper, the scraping members'15 of which drag over the bottom of the still, thereby continuously moving the pressure still bottoms toward the discharge pipe 16.

Where the crude oil or mixture is deliverecl into the upper portion of exchanger itsaaas 137 through pipe 38, it flows in relatively thin films to the still, and the vapors from the still bubble through it during its downward passage through the exchanger. The incoming oil has a cooling elitect on the vapors passing upwardly through said exchanger and this absorption of heat knocks back a certain proportion of the heavier hydrocarbons which would otherwise pass upwardly into the reflux air cooled condenser 40. The heat of the vapors at the same time causes the lightest portions of the fresh oil to be distilled off.

Assuming that the still is being operated under heat of approximately 750 degrees F., the vapors enter exchanger 137 at approximately 725 degrees F. and the temperature of these vapors is lowered to a considerable extent within said exchanger due to the dropping back of the cooled hetwier hydrocarbons from the reflux air cooled condenser 40, and the vapor passing through said last mentioned condenser leaves the same and passes through vapor line 44 at approximately 450 degrees F. The pressure on these hot vapors is relieved as they pass the valve 45, and if the pressure tends to increase or decrease it may be rendered uniform by opening or closing the valve. The vapors in vapor line 44 pass into condenser 43, wherein they are condensed and in the form of lighter benzines or lighter hydrocarbons, they pass through line 46 to tank 32.

The coke and heavier hydrocarbons discharge from outlet pipe 16 into coke settling pot 17 and the heavier portion of this residue is intermittently or continuously drawn off by proper manipulation of valved outlet 18. In ordinary practice, the taking oft of the heavier hydrocarbons through the outlet 18 is effected from four to six times every twenty-four hours. The lighter portion of the material within the coke settling pot passes continuously through tubular connection 21 to expansion drum 19. The pressure of the oil in the coke pot 17 is governed by the pressure control valve 22 which may be manually operated toward open or closed position to decrease or increase the pressure on the oil.

The degree of pressure maintained in st il 10 and coke pot 17 depends on the product being treated; for instance, the pressure required for ordinary crude oil will be from seventy-five to one hundred pounds, and the residuum in passing valve 22 drops to at mospheric pressure within expansion drum 1.9. The lighter hydrocarbons pass from expansion drum 19 through line to coil 2t. in exchanger 23, and the heavier residuum in expansion drum 19 passes through line 27 to coil 26 and from thence through line 29 .to receiving tank 28 and from whence it is eliminated or removed from the system.

liquefying in coil 24 are to a great extent .ab-

sorbed by the crude oil passing upwardly through exchanger tank 23 and as the crude oil is thus heated, certain lighter vapors are released and pass through line 31 to condenser coil 30 wherein they are condensed into unfinished gasoline and the latter passes through line 33 to tank 32 or said unfinished gasoline can be taken off, through line 34.

My improved method can be. used for the treatment of crude oil, gas oil, or fuel oil,

and by virtue of the fact that the method can be practiced continuously and Without shutting down for the elimination of the' coke, carbon and the like, the method has approximately twice the capacity of an ordinary batch still or the so-called semicontinuous pressure still. Inasmuch as the scraper is continuously operated while the method is being practiced, the heavier residuum in the still 10 is constantly being Withdrawn. As a result of the reduction in pressure by means of valve 22 in line 21, the coke forming material is caused to quickly drop to the bottom of expansion drum 19 and after passing through the exchanger tank 23 to assist in heating the incoming crude oil, it passes to receiving tank 28. v

A slight modification of the method ust described can be accomplished through the use of an apparatus constructed as illus trated in Figure 2, and in this apparatus the crude andgas oi] coming from exchanger 23 passes through a pipe 38 to an ordinary pipe still 14-7, wherein it is pre heated before being raised from approximately 300 degrees F. to approximately 650 degrees F. and when thus preheated, the oil I passes through line 48 to still 10. If desired, a line 49 may be led from the lower portionof exchanger 137 to line 38 for the purpose of conveying the reflux condensate from said exchanger 137 to line 38 and thus said reflux condensate mixes with and 1s preheated with the crude oil mixture in pipe still 147.

The pipe still should be maintained at a suflicicnt temperature to slightly crack the crude oil or mixture passing through it, but

this temperature should, not be such as to produce any appreciable amount of carbon in the coils of the pipe still as this would seriously interfere with the successful operation of the method. The pipe still provides a simple means for effecting prelimi-' nary cracking and at the same time it relieves the main still of a certain amount of work and reduces to a corresponding degree the heat required for said main still.

My improved method can be Very economically practicedby'virtue of the fact that a comparatively small quantity of fuel is required for heating purposes and as the distillation and the cracking of the oil under treatment is accomplished at one opera-. tion, the amount of equipment necessary for producing a given amount of merchant able product is materially reduced.

Thus it will be seen that I have produced a relatively simple and easily practiced continuous method for the distillation and cracking of liquid hydrocarbons which involves the cracking of the oil under pressure in a heated still, the-return of the heavier condensates to the still through the use of'a suitable condenser, reducing the pressure of the lighter vapors and condensing them under atmospheric pressure, the continuousremoval of the carbon and coke from the still, the delivery of said carbon and coke to a suitable container, the settling of the residue and the reduction of their pressure to evaporate. them by their sensible heat, the condensation of the residue vapors by the cooling action of fresh crude or gas oil passing to the still, and the that the illustration is merely diagrammatical and that any suitable apparatus may be used for practicing the method set forth and hereinafter claimed and that tempera tures and pressures in .the still Will vary according to the product under treatment.

I claim: '1. The hereindescribed method of treating hydrocarbon oil which consists in sub jecting a body of oil to heat and pressure, drawingo'ff the heavier oil from therfirst body of oil to form a secondbody ofoil also maintained under pressure, andv reducing the pressure on the second body of oil to effect the distillation of a portion of said oil.

2. The hereindescribed method of treating hydrocarbon oil Which consists in subjecting a body of oil to heat and pressure to release vapors from the oil, drawing off the heavier oil from the first body of oil and holding it under pressure, reducing the pressure-- on said ,heavier oil to efi'ect the distillation of a portion of said oil, then in: a body of liquefy the same, and then returning the resultant liquid to the main body of oil for retreatment.

3. The hereindescribed method of treating hydrocarbon oils which consists'in subjecting a bot y of oil to heat and pressure separately recovering released vapors from the oil, drawing oil the heavier oil from said body of oil and holding it under pressure, and reducing the pressure on the heavier oil to etlect a. separation ofits lighter constituents from-its heavier constituents.

l. The hereindescribed method of treating hydrocarbon oils which consists in holdoil under heat and pressure in a still to distill' olf the lighter tractionsof the oil, simultaneously drawing oft heavier oil and sediment such as coke from the bottom ot the body of oil in the still to form a second body of oil and sediment, reducing the pressure on the oil in the second body to effect a distillation of a portion of the lower boiling point hydrocarbons contained in said body, and removing seeiment from the second body.

5. The herein described method of treating oil which consists in rapidly distilling the body of oil under pressure, withdrawing vapors and condensing the said vapors under reduced pressure, withdrawing a residue tromthe body of oil and simultaneously separating the heavy carbonaceous material and tar from the oil, separating the remaining oil into a light and heavy traction, and returning the light fraction to the body of oil for further treatment.

6. The hereindescribedmethod of treating ydroearbon oils which consists in heating the oil to the cracking point under pressure to release the low boiling point vapors, returning the heavier condensates to the body of oil under treatment, reducin the pressure of the lighter vapors and con densing them under atmospheric pressure, removing from the body of oil under treatment the carbon and heavier residue, reducing the pressure on the heavier residue to evaporate a portion of it by its sensible heat, and condensing the residue vapors by subjecting them to the cooling temperatures of the oil supplied to the system for treatment.

7. The hereindescribed method of treating hydrocarbon oils which consists in subjecting a body of oil to the simultaneous action of heat and pressure and distilling OK the lighter fractions and simultaneously cracking the intermediate boiling point products, withdrawing a portion of the oil body under pressure, releasing the pressure on the said portion to withdraw the intermediate boiling point products therefrom and passing the said products into contact with the supply of oil delivered to the oil body under treatment in order to heat the said supply of oil and to distill the lighter hydrocarbons therefrom.

8. The hereindescribed method of treating hydrocarbon oils which consists in subjecting a body of oil to the simultaneous action ot heat and pressure to simultaneously distill elf the lighter fractions and crack the intermediate boiling point products, rcloasing the intermediate boiling point products at atmospheric pressure to the supply of oil delivered to the body of oil under treatment in order to heat said supply of oil and distill the lighter hydrocarbons therefrom, and utilizing the heat of the lighter hydrocarbons distilled from the body of oil under treatment for heating the supply of oil as it is delivered to the main body under treatment.

9. The hereindescribed method of treating hydrocarbon oils which consists in confining a body of oil and subjecting the same to the action of heat and pressure of a sutlicient degree to rapidly distill ofi the lighter hydrocarbons, separately vaporizing the intermediate boiling point products, providing a source of supply for the body of oil under treatment, and causing the vapors of the intermediate boiling point products to pass through the fresh oil so as to utilize the heat of the distilled intermediate hydrocarbons for heating the oil supply prior to its dclivery to the body of oil under treatment.

10. The hereindescribed method of treating hydrocarbon oils which consists in conlining a body of oil and subjecting the same to the simultaneous action of heat and pressure of sullicient degree to rapidly distill off the lighter fractions and to crack the intermediate boiling point products, removing the intermediate boiling point products in liquid form from the body of oil under treatment, reducing the pressure on the intermediate boiling point products to allow them to be vaporized, providing a source of supply of fresh oil and utilizing the heat of the distilled lighter products and inter1ne diate boiling point products for heating the oil supply prior to its delivery to the body of oil under treatment.

In testimony whereof I hereunto atlix my signature this 10th day of July, 1919.

JOHN V. COAST, JR.

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