US1378424A - Oil-cracking process - Google Patents

Description

A..-ROGERS.

OIL CRACKING PROCESS.

APPLICATION FILED JUNE 1. 1920.

Patented May 17, 1921.

ALLEN Roenns, or BROOKLYN, NEW YORK,

OIL-CRACKING rnocnss.

Specification of Letters Patent.

Application med June 1, 1920. Serial massacre.

To all whom it may concern. o

Be it known that I, ALLEN ROGERS, a citizen of the United States residing at Brooklyn, in the count of Kings and State of New York, have 1nvented certain new and V useful Improvements .in Oil-Cracking Processes, of which the following is a -specifi-. cation. I 1

This invention relates to oil cracking processes; and it comprises a method of producing large yields of motor fuel of the gasolene type from various higher boiling oils, where! I this end I take advantage of the fact that all in such higher boiling oil is vaporized, as in the presence of steam under conditlons and at a temperature, say about 600 F., glving thorough vaporization and the mixed vapors are thereafter progressively heated to paratively low cracking temperature, say, around 800 F., the vapors after reaching this temperature being cooled andcon'densed and the motor fuel produced recovered; all as-more fully hereinafter set forth and as v claimed.

material as regards the cracking whether the As is well known in the art, motor fuels of the gasolene type can be produced from most higher boiling gas oil, solar oil, fuel oil, still residues, etc., pyheating to a temperature above, say, 600

The heavier oils under these condltlons breakdown into lighter oils. It is not very oil be in the liquid or the vapor form, except that in the case of-liquid oil in order to attain temperatures above 600 F., it is in general necessary to operate under pressure. Cracking of vapors may also be done under pressure in order to secure somewhat, greater capacity of apparatus; it being-of course possible to get twice as much vapor in a given chamber under 15 pounds gage pressure as under atmospheric pressure. The difiiculty arises however that all the oils which it is desirable to crack into gasolene boil at relatively high temperatures; many of them not beginning to boil below 600 F. and all of them containing portions which boil far above that temperature. Therefore in compressin ing oil .it is dlfficult to prevent more'or less of the vapor going over to liquid even at cracking temperatures, that is above 600 F. In cracking oil in the liquid form under pressure the action is tolerably uniform and the same is true where vapors free of liquid, that is, dry vapors, are cracked. But if a com' oils, such as kerosene,

the vapors of any high boil-.

.production of coke and tar.

duce a suspension of oil in oil vapors ofany constant composition, it is obvious that such Patented May 17, 1921..

vapor, the operation becomes ira mixture cannot readily be cracked under constant conditions.

It 1s the object of the present invention to provide a process wherein cracking shall be under readily controllable conditions and to thepetroleum' oils, even the highest boiling,

,. can be' converted into vapors without substantial cracking if vaporization be done in the presence of a current of steam; a fact which is at the basis of the ordinary practics of using bottom steam in distilling lubr cating oil, wax oil, wax, etc. In the pres-.

oil-into a current of steam pletely volatilized; that is, everything except residual pitch-like or asphaltic constituents.

e proportion of steam to oil is made as small as will just secure this result of uniform volatilization, performed at about the temperature which experience has shown, in oil distillation, to be the maximum practicable for vaporization without much cracking, namely about 600 F. At 600 F as stated, most or all oils can. be converted into ence of steam without much decomposition or cracking; and in this stage of the operation I desire to secure, unchangedoil vapors. The mixture of steam and oil vapors, having once been made-,1

is next exposed to as low a cracking temperature as will suffice to give a good yield of motorfuel. sively from the initial non-cracking temperature of 600 F. up to about 800 F. With a methodical and progressive heating, if the temperature does .not finally much exceed 800 F., there is relatively little loss in the production of gas and in the concomitant The temperature referred to are those of' the vapors themselves; not of the tubes or the like through which the vapors pass. The temperature of. the tubes may be, and ordinarily is, much higher; but this is immaterial. The

fiow of mlxed vapors is so controlled with vapors in the pres- It is best to heat' progres cut invention I spray or mist a high boiling in such propor-. ,tion that the oil will be substantially comand the operation is as nearly as may be,

regard to the temperature of the tubes that in a furnace chamber as to be exposed to progressively higher temperatures. A con? venient arrangement 1s to have a series of horizontal tubes in a vertlcal chamber fired at its base, each tube being connected with passage is given-by which the tube may be poked or barred out, thereby keeping the interior of the tubesclean and free of coke. The deposition of any substantial amount of carbon in the tubes is undesirable for several reasons; one being that it interferes with the regularity of heating here desired and another being that the presence of coke is apt to institute irregular catalytic reactions. It is therefore desirable to keep the amount of carbon in the'tubes at a minimum. In order, further, to promote uniformity of heating, it is desirable to block out the center of each of the tubes by a central rod, thereby causing th mixture of vapors to travel next the inner periphery of the heating tubes as a thin annular layer. Cracking is a heat absorbing reaction and upon the regularity of the delivery of heat to the vapors depends much of the success of the operation; this being one of the reasons why the presence of unvaporized oil is undesirable. By blocking out the center of the tubes in this manner it is possible to obtain relatively thin annular layers of vapor through which it is not necessary for heat to pass any great distance, while at the same time securing the advantages of large sized apparatus. The interior elements used for blocking out the center of the tubes should of course be readilv removable.

In the accompanying illustration, I have shown, more or less diagrammatically, certain apparatus within the present invention and useful in performing the described process. In this showing-- Figure 1 is a view in central vertical sec- 131051, certain parts being shown in elevation, an

Fig. 2 is a fragmentary view in longitudinal section showing a method of connecting a blocking out pipe located in the crackin tube proper.

n the drawing, element 1 indicates as a whole a suitable furnace chamber fired at its base by burner 2. As shown, the burner gases strike a baffle wall 3 to give an even distribution of heat within the chamber, and

by .the ordinary distillation methods.

' inlet 6 leading through the walls of the furnace chamber to suitable connections (not shown) for supplying oil and steam. It is also provided with extensions 7 and 7 passing through the walls of the furnace. The twoextensions serve to support the tube at the ends and to give a straightway channel for cleaning out purposes. Within the furnace chamber the tube is provided with a T connection leading to a similar tube 8 just below it. This latter tube is also provided with end extensions like the first described tube and for the same purpose. The tube. 8 connects in turn by a T-connection 9 with another tube 10, and this in turn communicates with 11, 12, 13, 14 and 15 by T connections. The last mentioned tube carries outlet extension 16 taking vapors, gases and tarry products to suitable condensing and separating apparatus (not shown). The m0- tor fuel is separated from the condensaie s shown, the ends of the various tubes are located within wall recesses 17 and 18. In order to promote uniformity of heating of the mixture of steam and oil vapor going through the tubes, the tubes may be, as shown, provided with an interior blocking .out rod 19 forming an annular passage around it. Because of the presence of this rod the vapors passing through the tubes are caused to travel in a relatively thin annular, easily heated layer, An even better effect may be secured by using a tube in lieu of a rod, for this blocking out member 19, and by causing hot products of combustion to travelvthrough the tube. By so doing heat is applied both to the interior and to the exterior of the annular layer of oil vapor. Arrangements 'for this purpose are shown in the drawing. .In the fire chamber is located suction tube 20 delivering hot products of combustion to riser 21 which communicates, as best shown in Fig. 2, with interior blockingout tube 19. As shown in Fig. 2, this tube 21 screws into a special nut 22 having a double threaded engagement with the cracking tube and with the interior blockingout tube. For cleaning purposes, the upright passage with which 21 communicates is extended through the nut and are removed through one of the extensions (7 which is connected to'suitable exhaustingjor sucking means (not shown), 1 he recesses in the walls for the' 'accom-s modation of the ends of the tubular men nbers may be, and advantageously are", closed by doors 24, 3 W

What I claim is v 1- 1. 'The process ofcracking oil to form motor fuel and the like which comprises-mixing such oil with about the right amount of steamto vaporize it at a temperature of 600 F., and; produce. a vapor mixture substantially free of liquid and progressively heat-1' tor-fuel, which? comprises mixing such -o i1.- with about the right amount "of steam tovaporize it at at'emperature of 600 -F.a nd

. produce a vapor mixture substantially free 1 a,mama.progresses heatin the mix.-

Yture of'stea-m and [oil vapors from a. temperature Of abOIIfiTBQO Fb to about 800 F. 1 in-tubes ima thin annulantravelin layer,

(heat being i applied tosaid' layer bot, inter- .nall'y'an-dexternally) and condensing the cracked products; formed.

a In themanufacture of-motor; fuel fron -heavier' petroleum. oils, the process which 4 comprisesconverting, such heavier: oil. intoa' vapor substantially free o f. l=i'quid, I passingsuch vapor in ajthin current through an unobstructed annular-channel under heating conditions. adapted to raise its? temperature to a point not; substantially above 800 F. and diverting and cooling the vapors. after attaining a. temperature of ab'out 8l00- F J I11 testimony"whereof;Iaflix my signature V in the presence of two subscribing; witnesses.

Witnessesi, ,nHUM

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