US2187048A - Treatment of hydrocarbon oil - Google Patents

Description

Jan. 16, 1940.-

J. C. MORRELL TREATMENT OF HYDROGARBON OIL Original Filed Feb. 16, 1931 Patented a... 16, 1940 TREATMENT OF HYD ROCARBON OIL Jacquie C. Moi-tell, Chicago, 111., assignor, by rnesne assignments, to Universal Oil Products Company, Chicago, Ill.,-a corporation of Delaware Application. February 16, 1931, Serial. No. 516,271

I, Renewed June 14, 1938 "6 Claims. (01. 196-48)" This invention relates to the treatment of hydrocarbon oil and morespeciiically refers to the conversion of higher "boiling l'iydrocarbons into lower boiling hydrocarbons of a: more valu- 5- able character. I

In one ofitsspecif c aspects the invention relates to the conversion of hydrocarbon oils to produce thereby lower boiling hydrocarbons hav- .ing higher anti-knock value when used as motor 9 fuel than would normally be the case. More particularly the invention relates to the treat-' ment of gasoline or products within th-c boiling' range of gasoline to reform the same for the istics. Generally this comprises withdrawing separate fractions orcuts from theiractionator of i a distillation system or of a cracking system and subjecting the cuts or fractions so withdrawn, either after combining the same or sepalO rately, to conversion conditions suitable for each individual cut or fraction to improve the antiknock qualities of the fractions so withdrawn.

This invention may apply to straight-run gaso-' lines as separated by fractionation, or to cracked ll, gasolines resulting from theconversion of higher into lower boiling hydrocarbons.

It has been found that motor fuels from various crude oils have pronounced knocking char acteristics. Examples of these are Muskegon and 80 various Pennsylvania crude'oils. Analyses of the distillatcs within the. boiling range of motor fuels from these crude oils show that the fractions possessing pronounced knocking properties I may be'distributed throughout the distillate, the

86; distribution varying with the type and kind of crude oil. It is among. the objects of this in-T.

vention tdseparate and treat the components of hydrocarbon distillates showing pronounced knocking properties by segregating and subject- 40 ing the same to conversion "conditions at ele-' vated temperatures to improve their anti-knock characteristics,

In one specific embodimentthe invention contemplates the provision of aprocess which corn- 5- prises subjecting hydrocarbon oils toconversion conditions at'elevated temperatures, discharging the heated hydrocarbons intda reaction chamber, removing the products therefrom and in troducing the same into a vaporizer, separately 50. withdrawing the unvaporized liquid residue and the vapors, subjecting the vapors to fractiona tion, separately withdrawing from the fraction ator individual cuts or ractions to be combined for separate treatment under conversion ccndi tions at elevated temperatures, or separately purpose of improving their antidmock characteror the raw oil charging stock may be passed treating the individual cuts or fractions so wit-he drawn under conversion conditions at elevated temperatures, cooling, condensing the vapors leavingthe fractionator, and collecting the prod- 5 ucts therefrom. Inorder to illustratean operation of the process of the invention, reference is made tothe accompanying diagrammatic drawing, which shows one form. of apparatus suitable for carry ing out the invention. 7

Raw oil charging stock is introduced through line! controlled by valve 2 and is pumped by means e f-pump 3 through lined through one or several paths. The oil may pass through line 5 controlled by valve 6 through heat exchanger 1 through line 8 controlled by valve 9 through line to controlled by valve through line I2 into heating element 13 located in 1a suitable furnace H3, or the oil may be intro-': 20

duced directly from a feed line 5 into the trace at tionator l5, where it serves to cool the ascending vapors and is in turn pro-heated, combining with the reflux condensateform-ed by the fractionation of the vapors-arising in the fractionator l5, and the combinedfeed is subsequently passed. to the heating element I3. throughv line It controlled by valve I7 and through hotoi'l pump !8 into line I2. controlled by valve [2,-

directly to the heating element It throughiline l9 controlled by valve. 20 and through line it] in the manner heretofore described. The heated oil at conversion temperatures passes through line I5 controlled by valve it into the reaction chamber H, the total contents of which are withdrawn through line i8 controlled by valve I9 into the vaporizer 2! The unvaporized liquidand vapors are separately withdrawn from the vaporizer 2B. The liquid is withdrawn through line 2|, controlled by valve 22. The vapors pass throughline 23 controlled by valve 24 and enter thefractionator i5, wherein they are subjected to fractionation. The reflux condensate is freturned to the heating element lit for reccnver-j sion as hereinbefore described. .Fractionation maybe assistedby the introduction of a suitable cooling liquid in fractionator i5, for cX-E ample some of the distillate productsof the process or other suitable cooling fluids Side cuts or fractions are withdrawn from thedecks or trays not shown, of fractionatcr I5 'and ji n troduced into separate reboiling systems; 01"5605. ondary fractionators 25, 25'..and 25". The liquidside" cuts or fractions are withdrawn through. lines 26, 26- and 26", entering their respective tion chamber l1.

reboilers or secondary fractionating elements, being controlled respectively by valves 2?, 2'! and 21". Steam or other heating medium may be introduced into the reboilers or secondary fractionating elements through line 28' and 28" controlled respectively by valves 23, E9 and 29". The vapors leaving the reboilers pass back into the iractionator l5 through lines 30, 30 and 3D" controlled respectively by valves 35, 3! and 3|. The liquid withdrawn from the reboilers or secondary fractionators is passed through lines 32,, 32' and 32 controlled respectively by valves 33, 33 and 33", or the liquid may be caused to by-pass the reboilers by passing through lines 34, 34 and 34 controlled respectively by valves 35, 35' and 35". In either event, all of the liquid may be combined by passing the separate cuts or fractions through lines 36, 36' and 36 controlled respectively by valves 31, 3'! and 31', combining the same in line 38, from where it is withdrawn by means of pump 39 and passed through line 40 controlled by valve 4| into the heating element 42 located in furnace 42, where it is subjected preferably to high temperature conversion conditions to effect the maximum conversion into anti-knock components. All or a portion of each of the separate streams, or the combination thereof, may be passed through lines 43, 63 and 43" controlled respectively by valves 44, M and 44" and pumped by means of pump 15 through line 19 controlled by valve 80 into line iii and from there through pump l8 line l2 and valve l2 into heating element l3: or the individual cuts or fractions from the reboiler or secondary fractionating elements, or direct from the decks or trays of the fractionator may be introduced into the corresponding and respective heating elements 46, 45' and 46" located respectively in suitable furnaces 41, ll and 4'!" through lines 48, 48 and 48 controlled by valves 8!, 8| and 8|" respectively to be subjected therein to conversion conditions, preferably at high temperatures, to effect maximum conversion into products of high anti-knock value. The heated hydrocarbons leaving the heating element 42 pass through line 49 controlled by valves 50 and 5! into the transfer line [5, or directly into the reaction chamber H, or in the event that it is desired to operate heating element 42 at a pressure lower than that existing in the heating element l3 and/or reaction chamber ll the heated hydrocarbons leaving the heating element 42 are by-passed through line 52 controlled by valve 53 by means of pump 54, wherein the pressure is raised, and through line 55 controlled by valve and through line 49, in the manner hereinbefore described. Similarly, the heated hydrocarbons leaving the heating elements 46, 46' and 45" pass through lines 6i, 6% and 62" controlled respectively by valves 62, 52 and 62" and through line 63 controlled by valve 34 into the transfer line IE or directly into the reac- In some cases it may be desirable to introduce the vapors from the heating element 42 or the heating elements 46, 28 and 46" directly into the vaporizer 2E3, particularly when it is desired to reduce the hydrocarbons treated to coke and distillate by what is commonly termed the non-residuum operation. In this case the heated hydrocarbons leaving the heating element 42 are passed through line 49 in the manner previously described and through line 66 controlled by valve into line 18', or preferably directly into the vaporizing drum or chamber 20'. Similarly, the heated hydrocarbons leaving heating elements 46, 46 and 46" pass through line 63 and through line 61 controlled by valve 08 into line I8, or preferably directly into the vaporizing drum or chamber 20. The highly heated vapors assist in vaporizing the liquid in the vaporizing chamber 20 not only by virtue of the heat contained in the vapors but also the partial pressure of the vapors which reduces the average boiling point of the liquid within the vaporizing chamber. A plurality of vaporizing chambers is desirable in operations of this kind, permitting the accumulation of coke in one while the others are being cleaned or otherwise prepared for cutting into the system without interrupting the operation of the process and permitting continued operation over long periods of time.

The vapors leaving the fractionator 15 pass through line 69, controlled by valve 10, through cooler and condenser H, line 12, controlled by valve 13, the condensed liquid being collected in receiver 14, from which it is Withdrawn through line 15, controlled by valve IS. The gases are withdrawn from the receiver through line 17, controlled by valve 18, which valve may also serve to control pressure on all or part of the system.

The operating conditions employed may vary over a wide range, depending upon the type of charging stock treated and the results desired. Uniform pressures or differential pressures varying from atmospheric to high superatmospheric may be employed. Pressures varying from atmospheric to 2000 pounds per square inch, more or less, are suitable. Temperatures within the cracking range are employed; for example, from 800 to 1200 F., more or less. The high temperatures are suitable when gas-making is one of the objects of the process. Preferably, the heating element [3 is operated at relatively low temperatures with respect to the other heating elements 42, 46, 46 and 45", the latter being operated at temperatures normally considered within the vapor phase cracking range, which is in excess usually of 1000 F., although any suitable cracking temperatures may be employed.

Itis to be understood that the invention is not limited to the treatment described, as the principles and concepts of the invention permit of a very broad application. For example, if it is desired to improve the anti-knock value or knock-rating of gasolines containing'fractions or components of markedly low anti-knock value, such as Pennsylvania straight run gasoline or gasoline from Muskegon crude oil or similar gasolines, these may be separated and segregated and separately treated. As an example of the relationship between the knock-rating and the boiling range of a straight run Pennsylvania gasoline, the following data is given:

F. Bcnml Initiall l0 equivalent Similarly, the'gasoline from a-Muskegon crude oil showed the following properties:

In the first setof data theanttknock value of the individual fractions are given; in the second set the benzol equivalent, which indicates the anti-knock value equal to a blend of Pennsylvania straight run gasoline and benzol containing the indicated percentages of the latter, is based on the composite of the given fraction with-all the fractions preceding.

It is. clearly evident, however, that by suitable fractionation of the gasolines various fractions or cuts may be removed and subsequently subjected to retreatment according to the principles of the present invention to increase the antiknock value thereof.

As a specific example of results obtained by the operation of my invention a oil is treated by the method described. The low boiling components of the crude oil are separated into the fractionating column and the separate cuts are withdrawn, particularly those which are low in anti-known value. From the specific example given above, it is evident that the fraction boiling above 360 tor i37 F'., may be withdrawn and combined for a single separate treatment or subjected to separate treatment in several cuts or fractions. The fractions withdrawn in the case under consideration consist not only of the straight run naphtha but also contain the intermediate boiling cracked products, some of which likewise have poor anti-knock value. Two such fractions are separately treated, one being heated in the separate heating elements to a temperature of 975 F. and that having the lower antiknock value of the two is heated to a temperature of approximately 1050 F. The conditions of treatment in the main heating element cor responding to. l3 wherein are treated the unvaporized material leaving the bottom of the fractionator l5, together with reflux condensate withdrawn therefrom, are approximately 920 F. and about 200 pounds pressure per square inch. The pressure in the reaction chamber ll" is approximately 200 pounds per square inch also. The pressure in the heating elements in which the two side cuts are treated is likewise approximately 200 pounds per square inch; The pressure in the vaporizer, fractionator, condenser and receiver is approximately 30 pounds per square inch, the elements succeeding the fractionator being equalized in pressure with the fractionator. When the oil is treated without reconversion of the side cuts withdrawn from the fractionator l5, the anti-knock value of the motor fuel produced thereby is approximately benzol equivalent. However, when treated in the man- Muskegon crude ner described the anti-knock value creased to. 55% benzol equivalent.

In, another case a Pennsylvania 40-44 A. P. I. distillate is treated' Approximately 60% of the low. boiling product of the process is withdrawn directly from the fractionator as side cuts and subjected to retreatment in a separate heating coil. The total yield of gasoline is approximately 68%,,making a total of approximately 40% of the charging stock withdrawn as a side out. The side out is subjected to a temperature of approximately 1000 the main charge being introduced directly into the heating element corresponding to l3, which is heated to a temperature of approximately F. The pressure on the may be inheating element It is approximately 300 pounds per square inch and a similar pressure is maintained in reaction chamber H. The pressure on the heating element 42, wherein the side out is reconverted, isabout 200 pounds per square 20, inch. The pressure upon the vaporizing chamber,

fractionator, condenser and receiver is approximately 30 pounds per square inch, allowing for pressure drops through that part of the system,

whereas the product would normally have an anti-knock value of approximately 40% benzol equivalent, were the side cut'not treated, a product having an anti-known value of approximately 65% benzol equivalent can be obtained when the process is operated in the manner described.

In both cases the boiling range of the product is substantially improved, particularly the intermediate boiling points are lowered, as well as a large improvement in anti-knock value.

The yields of gasoline are not substantially decreased, although some decrease is noted, but this slight disadvantage is greatly offset by the very marked increasein anti-knock value of the gasoline, which in some cases is rendered'marketable and in' other cases serves as a valuable blending agent in improving the anti-knock value of'the motor fuels otherwise deficient in this desirable property.

The examples are-illustrative only of some of the broad possibilities of the invention.

I claim as my invention:

-1. A- process for producing anti-knock motor fuel from crude oil containing gasoline which comprises introducing the crude into a fractionating zone and contacting the same therein with cracked vapors formed as hereinafter set forth thereby vaporizing'the gasoline from the crude and forming a mixture of unvaporized crude and reflux condensate separated from the cracked vapors. condensing the heavier portion of the gasoline from the comminglcd crude oil vapors and uncondensed cracked vapors while retaining the lighter portion of the gasoline in vaporous form, heating said mixture of unvaporized crude reflux condensateto cracking temperature, inchependentlv heating said heavier portion of the gasoline to a higher cracking temperature adequate to increase its anti-knock value and then commingling the same with said mixture, separating the thus commingled oils into vaporous and residual products, supplying such separated vaporous products to the fractionating zone as said cracked vapors, and finally condensing and collecting said lighter portion of the gasoline uncondensed by the fractionation.

2. A process for producing anti-knock motor fuel which comprises fractionating crude petroleum oil together with cracked products and separating from the crude oil and cracked products a gasoline fraction of satisfactory anti-knock value, a fraction containing natural and cracked gasoline hydrocarbons of inferior anti-knock value and a fraction heavier than gasoline, recovering the first-mentioned fraction, supplying the last-mentioned fraction to a heating zone and heating the same therein to cracking temperature under pressure, subjecting the second-mentioned fraction in a second heating zone to conversion conditions of temperature and pressure adequate to increase the anti-knock value of the gasoline hydrocarbons contained therein, and supplying resultant conversion products from said second heating zone and cracked products from the first-mentioned heating zone to said fractionating step.

3. A process for producing anti-knock motor fuel which comprises removing cracked vapors from an enlarged zone and fractionating the same in a fractionating zone in direct contact with crude oil containing natural gasoline thereby vaporizing gasoline from the crude and condensing fractions of the vapors heavier than gasoline, passing liquid products heavier than gasoline from the fractionating zone through a heating zone wherein they are heated to cracking temperature under pressure and subsequently discharging the same into said enlarged zone, removing gasoline-containing distillate from the fractionating zone and passing a portion of the gasoline hydrocarbons, including the low antiknock constituents of the natural gasoline and the cracked gasoline, through a second heating zone, heating such gasoline hydrocarbons in the second heating zone sufficiently to increase the anti-knock value of the low anti-knock constituents thereof, discharging the thus heated hydrocarbons into said enlarged zone, and. recovering the remaining portion of said gasoline-containing distillate removed from the fractionating zone.

4. A process of hydrocarbon oil conversion which comprises subjecting a crude oil containing gasoline to distillation temperature sumcient to vaporize the gasoline and separating the gasoline from the crude, passing portions of the crude heavier than gasoline through a heating zone and heating the same therein to cracking temperature under pressure, simultaneously passing gasoline boiling range hydrocarbons separated from the crude through a second heating zone maintained at higher cracking temperature than the first named heating zone and heating the same therein sufficiently to enhance the antiknock value thereof, commingling vaporous conversion products of said portions of the crude and of said gasoline boiling range hydrocarbons and fractionating and condensing the commingled vapors.

5. The process as defined in claim 4 further characterized in that the gasoline vaporized from the crude is separated into a light fraction and a heavy fraction, the light gasoline fraction being recovered without subjection to cracking conditions and the heavy fraction being supplied to the second heating zone as said gasoline boiling range hydrocarbons.

6. A process of hydrocarbon oil conversion which comprises subjecting a crude oil containing gasoline to distillation temperature suflicient to vaporize the gasoline and separating the gasoline from the crude, passing portions of the crude heavier than gasoline through a heating zone and heating the same therein to cracking temperature under pressure, separating the gasoline vaporized from the crude into a light fraction and a heavy fraction and recovering the former, passing the heavy gasoline fraction through a second heating zone maintained at higher cracking temperature than the first-named heating zone and heating the same therein sufiiciently to enhance the anti-knock value thereof, ccmrringling the heated products from said heating zones and separating the same in an enlarged separating zone into vapors and residue, and fractionating and condensing the separated vapors.

JACQUE C. MORRELL.

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