US1426813A - Process for the production of low-boiling-point hydrocarrons - Google Patents

Description

. BLACK. Pnocess Foa THE PRODUCTION oF Low Bouma vommuaocmows.

Paeted Aug. 22, E922.

APPLICAUON FILED DEC-12, 19.!9. wwwa.,

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Patenten an@ es, rase..

Application lled neceinber 1221919; erick No. Medea.

carbons derived from crude petroleum or itsequivalent, into those of lower boiling-point,

and to a process especially useful 'in'increasing the production of, so termed, gasoline yfrom relatively heavy hydrocarbonshaving high boiling points. is known thatby'the processes at present employed for producing gasoline without crackin a comparatively small percentage, from a raction of one percent to thirty percent or more gasoline, is obtained by ordinary distillation Qtherrude Oil. J

rl'he processes commonly in vogue for pio-l duciiig gasoline, other than -that produced by ordinary distillation of the crude oil, rely fundamentally upon heating the hydrocarbons to certain temperatures under pressure to'produce cracking, taking the vapors oii' atahigh temperature under the pressure einployed and condensing the same. As distinguishing fundamentally from such pressure-vapor processes, my present proctss, for brevity, may be termed a pressure-liquid process, since l do not vaporize the hydrocarbons while at cracking temperature but, rather, maintain a pressure on the hydrocarbons above the vapor pressure thereof at the cracking temperature employed Where- ,by the deposited products of decomposition willrbe in a condition easily removable from the apparatus. I tlienireduce the temperature of the whole body of hydrocarbons to such a point as may be desirable for the subsequent treatment. if the hydrocarbons are reduced to normal temperature they will have the appearance of crude oil with many of its characteristics and they may be termed a crude equivalent.

ln this improved process I not only maintain pressure on the hydrocarbons under treatment to prevent any mate-rial vaporization thereof, but I preferably maintain them at cracking temperatures while in liquid form for a prolonged period of time and retard How of the liquidvhydroc'aiibons While at cracking temperaturee so that dissociation andpolymerization wil be as complete as possible 'before the hydrocarbons are cooled or subjected to the subsequent treatment required toseparate the low boiling from the high boiling point hydrocarbons. ll maintain pressure on the hydrocarbons under treatment until they arecooled if the immediate object is to crack and store the prod- -uct for subsequent treatment as hereinafter described. lf, however, it is desired to crack and then immediately distill, pressure is t maintained on the hydrocarbons under treatment during the cracking, dissociation and polymerization of the hydrocarbons, after which' distillation of thefhot hydrocarbons at atmospheric' or higher 'pressure will be 'effected in any suitable distilling and fractionatirig apparatus, two examples of which will be described hereinafter.

To maintain the hydrocarbons at cracking temperatures for the prolonged period of time and at the same time to cause theV deposition of carbon produced by the cracking operation, li preferably reduce the speed of low of the hydrocarbons while they are at the crackingl temperatures and, in this particular instance, ll accomplish this by discharging the heated hydrocarbons `from the cracking or heating coil into a digester or cracking chamber of larger cross sectional area than that of the cracking coil tubes, by maintaining 'the pressure on the hydrocarbons l prevent vaporization and the carbo naceous products of reaction are deposited in a condition easily removable from the apparatus. y'

In the practice of my process,- I may treat for the production of gasoline the intermediate cuts resulting from first subjecting crude petroleum or a crude equivalent to any of the heretofore known distillation processes. By such first distillation process there may result, for example, gasoline amounting in volume to from 15 to 2() percent, more or less; asphalt, coke and the like, 20 percent; and intermediates. 65 percent, more or less.

-The percentages given are only approximate and may vary considerably with petroleum from diiierent localities. These intermediates, when subjected to my process, are

in storage for a time and then fractionatd."

When t us allowed to stand in stora fore fractonating, larger amounts of t e low lli boilingoint hydrocarbons appear to be produced t an if the cracked hydrocarbons be immediately fractionated.

'llo perform my process ll have provlded a `suitable a paratus and, though 1t is to be elevation, partly in section, of the appa.

ratus; and

Fig. 2 is a sectional elevation on llne 1ndicated by :v2-a2, Fig. 1.

The apparatus illustrated 1n the drawings is constructed as follows: In a furnace A there is provided a suitable lower combustion chamber 1 having at one end thereofv a burner 2 and having at its opposite end an opening 3 through which the productsof combustion can pass into a coll-heatmg chamber 4. In thel coil-heating chamber 4 is a cracking coil 5 which is heated b y the4 products of combustion that pass through the chamber 4. The coil-heating chamber 4 is provided at the end opposite that having the opening 3 with an opening 6l through which the products of combustion escape into an upper combustion chamber 7 rovided at one end with a burner 8.. Thus the chamber 7 is not only heated by the products of combustion from the burner 2 but may be heated additionally by tire from the burner 8. l

From the combustion chamber 7 the products of combustion liow through an opening 9 into an intermediate coil-heating chamber 10 having a pre-heating coil 11. The roducts of combustion flow from the chamt r 1'0 through an opening- 12 into an upper coil-heating chamber 13 in which is positioned a heating coil 14. From the chamber 1.3 the products of combustion discharge through a flue 15.- |ll`he fuel furnished to the, burners 2, 8 may be gas or 'oil and the burners are capable of raising the various chambers to the temperatures required for performing the process.

The coils'5, 11 comprise a number of straight tubes 16 which pass through perforations 17 in the front and rear walls of the 18 are provided with removable vplugs 19.

'Thus it is clear that the coils 5, 11 may be readily cleaned when such cleaning becomes necessary or desirable. The outlet end of the coil 5 is provided with a pyrometer 20 sothat the temperature of said coil and its contents may be noted from time to time during the operation of the apparatus. The outlet end of coil 5 is connected by a tube 21 to a digester or combined cracking charm nascere;

ber and carbon catcher 22, preferabl oi larger cross sectional area than the crac ing tubes 16'. The cracking chamber 22 ma lbe formed of a piece of relatively large tubing and removable heads 23 are fitted to the opposite ends of the tubing to form tight closures therefor. The heads 23 are detachabl held in place by okes 24 and screws 25.

he cracking cham r 22 is connected by a tube 26 to a heat interchanger 27, said tube 26 being connected with the inner tube 28 of the interchan er. The' outer tube 29 of the interchanger 1s connected by tubing 30 to one end of the coil 14 and the opposite end of said coil is connected by tubing 31 to one `end of the coil 11. The outlet end ofl the coil l1 is provided with a pyrometer 32 so that the temperature of said coil and its contents may be readily observed at intervals. The outlet end of the coil' 11 is connected by tubing 33 to the opposite end of the coil 5 from that provided with the pyrometer. The outer -member 29 of the heat interchanger is connected by tubing 34 with a pump 35 which receives liquid hydrocarbons throughv a supply pipe 36 connecting with a tank 37. The tubing 34 is provided with a pressure gage 38.

The inner tube 28 of the heat interchanger Vis connected by tubing 39 to one or more eration. llf so desired each still may be op crated independently of the other, each receiving its supply of oil from 39 throughthe valve' 43, the .cross-overs 41 being blanked off. The tubing 39 is provided with a valve 42, and between said valve 42 and the valve 43 with a pressure regulator and discharge valve 44, said pressure regulator serving to keep the requisite pressure on the liquid hydrocarbons in the cracking coil 5 and cracking chamber 22 and also in all other parts of the apparatus between the pressure regulator and the -pump 35. Each still 41 is connected by tubing 45 to a condenser 46 and each condenser is connected by a tube 47 to a gas trap 48. Each gas trap 48 is" connected by tubing 49 to a gas absorber 50 and the gas absorbers are 'provided with gas vent pipes 51 to carry the gas to any desired place. Each gas trap 48 is connected by a tube 52 to a sampling box 53 and each sampling box is connected by tubing 54 to a storage tank 55. One or more ofthe storage tanks 55, in this instance two ofthem, are connected by tubing 56 to the tubing 36.v The tubing 56 vis provided with valves 58 and the tubing 36 is provided with a valve 59.

The tubing-39 is connected by tubing 60 with a cooler 61 which in turn is connected by tubing 62 to a gas trap 63. The tubing `een prei/'idea wait a 'piastre regenerar ricadere and a pressure gage 65 between the pressure regulator and the ce oler. The gas trap 63 is connected by tubing 66 to a gas absorber 67 and the gas absorber is provided with a gas vent tube 68. The gas trap 63 is'connected by tubing 70 to a storage tank 7l. rlhe tubing is provided with a valve 72 and the tubing 39 is provided with a pressure gage 73. To the tubin 7() is connected a tubing 74: having a va ve 75, and the tubing 74; connects with the tank 37. rllhe tubing70 is provided between the tubing 74'and the tank 71 with a valve76.'

y The process is performed in the above described apparatus as follows: The tank. 37 will be supplied With the hydrocarbons to 'be treated. Crude petroleum or a crude 'equivalent may be employed, but li preferably use the intermediate fractions resulting from treating crude petroleum pr a crude equivalent by prior known processes. Among such intermediate fractions, for example, are those which are not capable of being further cracked by the relatively lowpressure processes to produce the much de' sired low boiling-point hydrocarbons. rll`he valves 59, 7,2and 75 are opened and valves.I 4:2, 58 and 76 are vclosed and the pump35 is operated to force liquid hydrocarbons from ythe tank 37 through the system and to pro duce a pressure of several hundred pounds in that portion of the system between the pressure regulator 64 and the pump thus insuring that said portion is entirely illed with the liquid hyrocarbons which are to be treated. The fires are then started at the burners 2, 8 so as to heat the coils 5, 11, 14e' to the required temperatures.

The pump is continued in operation and the hydrocarbonsv circulate continuously. Until cracking has taken place to a satisfactory degree the oil is bypassed through valve 75 and tubing 74 to tank 37 to be re-run. rEhe p vronicters 20,32 will be consulted to determine the temperature of the hydrocarbons in the coils 5. 11. The temperature of the coil 11 will be preferably maintained just under that required for cracking of the hydrocarbons, though it the temperature should rise higher and an incipient cracking of the oil take place the tubes may be readilv cleaned of carbon deposits when they become choked. The coil 5 is heated to a predetermined cracking temperature.

The degree ot' pressure employed is predetermined for the particular hydrocarbons being treated. The temperature required for the particular hydrocarbon being treated may be determined by the increase of Baume gravity oi a sample` supplemented usually by a distillation test to determine the yield of hydrocarbons boiling between certain specific temperature limits.

Assuming that one or more of the stills 4:0

.vents vaporization in the cracking coil 5 and creases because of the relatively large cross is tovlbe utilizedpsfthatut'he predetermined cracking temperature has been reached, and that the regulator 4t has been set -iter the predetermined operating pressure, the valves 4t2, 4 3 will be opened and the valves 78, 72 will be closed, thus causing the hydrocarbons to flow into the still or stills when the desired degree of cracking is reached. 'llhe pump 35 1s continued in operation so as to maintain the desired pressure rearwardly ot the pressure regulator M and so as to cause the hydrocarbons to flow under such pressure through the various coils and through the cracking chamber 22. The pressure precracking chamber 22. Before the hydrocarbons discharge from the cracking coil 5 they reach the cracking temperature and the time of subjecting the hydrocarbons to the cracking temperature is prolonged by reason of the hydrocarbons dischargmg trom the coil 5 through the tubing 21 into the cracking chamber 22. ln the cracking chamber 22 the rate of flow of the hydrocarbons desectional area of the cracking chamber. The cracking chamber 22 is suitably insulated against loss of heatand thus the hydrocarbons are maintained at @cracking temperature during the flow of the hydrocarbons through the cracking chamber.

Not only does the cracking chamber prolong the cracking operation so as to insure that the cracking of the hydrocarbons at the given tempera-ture is complete, or substantially complete; but deposition of carbon occurs in the cracking chamber to a much larger extent than in the coil 5, for the reason that the flow of l1 drocarbons is slower in the cracking cham er than in the coil 5, thus permitting the free carbon produced in the cracking operation to become at- -tached to the relatlvely large Wall area of the cracking chamber.

From the cracking chamber 22' the 11o cracked hydrocarbons, still at comparatively high temperature, flow through the heat interchanger 27 .Where they are cooled to a greater or less degree, depending u on the area of the vradiating surface of thel eat interchanger. The heat is absorbed in the interclmngcr by the cooler hydrocarbons being. fed into the system by the-pump 35. rllhus the heat intcrchanger serves to initially heat the'hydrm-arbons being treated and further l2@ heating of the hydrocarbons is eected, between the heat interchanger and the coil 11, in the coil 14 around which flow the hot waste gases passing from the chamber 10 through the chamber 13 to the Hue 15.

The cooling capacity of the interchanger 2i" may be such as to cause those hydrocarsay, it it is not desired to immediately fractionate the cracked'hydrocarbons, they mayvbe `clischargpd into the tank 71 by olpemng the valves 2, 76 and closing the va ve 42; that, if the cooling capacity of the interchanger 27 be sulicient, 'the lighter as Well as the heavier hydrocarbons 1n the crude equivalent Will dischargeas liquids without I running them through supplemental coolin means; and that, if the cooling capacity o the interchange is not sumcient to -prevent vaporization o the cracked hydrocarbons when release of the pressure occurs through thevalve 64, than the coolerl 61 will be operated to complete this cooling operat1on.

l have discovered that, by'allowing the crude equivalent to lstand for a more 'or less extended period of time to ermit of further polymerization in the ta 71 before fr ac tionating, upon subsequently ractionatmg the crude e uivalent it yields a greater percentage of t e more stable lighter hydrocarbons desired, hence the advantage of imme- 40 to. eect distillation.

.carbons by operation of the heat interchanger 27 the incoming hydrocarbons may y be by-passed in a manner easily understood. rlhe hydrocarbons after arting With at least some of their heat in t 1e interchangerv 27 will discharge into the first still 40 and the vapors will be carried over into the associated condenser 46. lf continuous distillation is employed the unvaporized hydrocarbons will llow from the first still into the second still through the cross over 41 and another cut will be made and the vapors will discharge into the associated condenser. Also from the second still the unvaporized hydrocarbons will discharge into the third still throu h the cross over 41 and the vapors taken oil rom the third still will discharge into the associated condenser 46. Whatever gas remains after the vapors pass through the condensers will pass into the absorbers -50 and maybe recovered in part in a manner vention relates.

well understood in the art to which this in- To achieve -the distilling just described the stills will, of course, be progressively heated from left to right.

.- The condensates pass from the condensers 46 through the 'tubing' 54 into the storage tanks 55. In this instance, the lighter o`r lower boiling point hydrocarbons, which it isthe desire of the rener to recover, are

namely an process, l em loy the relatively high tem-4 'ven 0H inthe first still, and the intermeiate fractions in the second and third stills and the carbonaceous matter or residue is deposited in the third still. It may be as- -sumed, for example, vthat the condensed vapor from the first still is approximately -56 Baume, that the condensed vapor from second still is approximately 35 Baume and 'diate ractiops again through the coils 5 11,

14 and cracking chamber 22` to be. recracked.

The intermediate fractions from the second and third stills 40, however, 'ma be re-run independently through any suita le still for redistillation so as to separate the lighter fractions from the heavier, and such lighter fractions may then be thrown in with the distillate from the irststillA and the heavier fractions may be vstored and then re-run through the ap aratus. Y

lf it be not esired to distil the cracked hydrocarbons at once,the valves 42, will be closedand the valves 72, 76 opened, and the cracked hydrocarbons will then Vfilovv yfrom the tubing 39 throu h the tubin 60 into the cooler 61. This coo er 61 may e dispensed with if the heat interchanger 27 is made of suli'iciently great cooling capacity to absorb substantially all of the heat artificially applied to the hydrocarbons. The cooler hydrocarbons pass from the cooler 61 through the tubing 62 and pressure regulating valve 64 into'the separator 63 and the liquid hy# drocarbons flow from said separator throu h the tube 70 into the storage tank 71; T e hydrocarbons in the storage tank 71 may be termed a crude equivalent since it resembles to a large degree crude petroleum. Tllis crude equivalent at any desired time after `its production will be fractioned to segregate the low boiling-point h drocarbons desired from those of'higher oiling-point.

."vlhough the above described processditl'ers considerably from the process of refining crude petroleum oil atented to George L. Benton May 25,1886, o. 341,564 and,thou h said Benton process was conceived for t e purpose of reducing a diiierent roduct, luminating oil, than t is new peratures an pressures of the Benton process in the cracking o'peration; but, instead of spraying the hydrocarbons at crack# ing temperature into a vaporizing chamber to produce the homogeneous illuminatingoil-of the Benton process, l eect a prelonged cracking operation under pressure,

iet

Maaate nl@ mata a@ i or newer at naar hydrocarbons while at cracking tem eratures, then reduce the temperature o the cracked hydrocarbons-to or below the va porizing` temperature of the low boilingf point hydrocarbons which it is desired to i recover, and finally fractionate the hydrov However, the prolongedcracking temperature and pressure may be obtained by any other suitable means. ln this manner ll' am enabled to produce a greater volume of low boiling-point hydrocarbons from a Vgiven quantity of crude petroleum or a crude equivalent than is possible by prlor known processes. F or this reason the process is very useful and valuable since the production of low boiling-point hydrocarbons such as gasoline by present known processes can scarcely keep pace with the increasing demands therefor, mainl as fuel for internal combustion motors.' lso by prior known processes there is produced an over supply of intermediate fractions which l am enabled by this process to crack to produce high grade gasoline, and l prefer to treat such intermediate fractions rather than crude oil because the prior distillation removes a large amount of carbonaceous material which thus cannot act to foul the apparatus. Such intermediatefractions cannot be readily converted into high grade gasoline by the proc= esses now employed in the art.`

'lhe hydrocarbonsof relatively high boiling-point produced in the second and third sti ls, in this instance, will be preferably re-run through the apparatus and cracked by my process, and for this purpose, when Vquantities of the relatively high boilingpoint hydrocarbons have been produced by the still, the valve 59 willbe closed and the -valves V58 will be opened to permit the pump 35 to force such hydrocarbons throu h the s stem for cracking and redistil ation. rom this it is clear that the process may be a continuous one, not only in the sense that new supplies of oil are constantly being treated by the process, but that a relabons from the original oi tively large proportion of the product is rerun from time to time to re-crack the relatively high. boiling point hydrocarbon pre-` viously roduced 1n the apparatus, thus enabling t 1e production of possibl 50 per cent or more of low boiling treated.

'lhe cracking o eration is continued in the coil 5 and crac ing chamber 22' until the increasing diderential pressure between the i ages 38, 73 or 38, 65 as the case may be, denotes such increased resistance to the dow of the oil4 as to indicate that said coily or cracking chamber is seriously fouled with carbon, renderingthe apparatus inoperative; whereupon the fires are shut ed and the fouled tubes 1G and chamber 22 are cleaned,

to be separately cleaned of the carbon deposited therein.

The higher the temperature and lo er the timeI employed for cracki the ydroca rbons the larger will be the yield of low boiling-point hydrocarbons and the greater will be the production of carbon, so that in a practical commercial plant it is necessary for the operator to choose such a tem? perature and pressure and duration of such temperature and pressure that as long a run as possible may be made, without the necessity of cleaning out the carbon, consistent with a suilicient yield of gasoline to make the operation of the plant profitable.

The process maybe better understood by a specific example as follows:

ll have operated with my `p on an oil that begins to crack at about IZ50 F; but reducing a'low yield-of gasoline. By heating this oil to about 800 F. the yield of gasoline was increased, and by heating the oil to 850 F. or as high as 900 lF. Ithe yield of gasoline was as hi h at 30% of the original stock employed. his latter temperature may be too high in practice to inconsiderable and negligib e degree, since such vaporization would cause rapid dep'osition of carbonaceous material in the tubes and consequent quick fouling thereof.- lin practice l'have successfully employed, and

pheres and as high as 1000 to 1200 pounds per square inch and even higher for some oils. The pressure to be employed is dependent in a great measure upon the character of the oil being treated and the tem- I prefer a pressure of not less than 35 atmosperature to which 4the oil is subjected in the cracking operation, since the hlgher the temperature employed the greater the prespoint ydrocar-.cfsure required to prevent any substantial vaporization of the oil. l

lt is to be noted that the reduction in 4'temperature of the cracked hydrocarbons to 13.0

v of the third. condenser as bein tional condensers and for this or below the vaporizing temperature of the low boiling-point hydrocarbons which it is' desired to recover enables me to avoid .the production of a homogeneous vapor such as that made by`Benton in his production of illuminating-oil. lBentons process enabled him to increase the production of illumi mating-oils and decrease the Iproduction of benzine, while my my process the production of gasoline is increased and that of the less valuable intermediate fractions is de creased. This result .is effected in the4 apparatus shown by employing crackingFtemperatures of from 750 F.to1200 or -even'higher for some oils, and preures in nected by tubing 81 with the rst of a series of fractional condensers 82, the coils of which discharge into gas or vapor traps 83. The gas traps are connected by tubes 84 Vwith 'samp ing` boxes 85. 'lhe vapor trap 83 of the lirst condenser is connected with the coil of the second condenser, and the vapor trap'o the second condenser is c'onnected with the coil of the third condenser by tub ings 86. Each of the sampling boxes -85 is connected by tubing 87 to a suitable 'recap tacle or tank, the tubes 87 being provided with valves 88, respectively. For example, the discharge pipe 87 of the first condenser 82 ma be considered as vbeing connected with t e first tank 55 beginning at the left in Fig. l of the drawings, the tubing 87 of the second condenser as being 'connected with the second tank 55, and the tubing 87 connected with the tank 55 at the right si c of Fig. 1. These connections with the tanks 55 are not shown since it would tend to congest the drawing to show them, but it is understood' suchv connections exist so that the heavier 'and lighter intermediate fractions from the first and second 'condensers 82 may -be readily re-ruii through the apparatus for recrackin in a manner hereinbefore described. he as trap of t e third condenser is connected sorber 90 provided with a vent pipe 91. A pipe 92 having a valve 93 discharges from the chamber 79.

ln order to fractionally condense the cracked hydrocarbons, the valve 77 on the tubing 38 will be closed, as well as the valve by a tube 8 with a gas ab- Maaate l72,'aid the valve 8 'will be opened; thus al# lowin the hot liquid hydrocarbons discharging' vt rough the pressure regulator 44 to yaporize in the chamber 79. The tarry products or other carbonaceous matter thrown through the .pipe .92. vllt is understood that the temperature of the liquid hydrocarbons in' the tubin 39 and connecting tubing 80 will be su ciently high under"4 the pres- -sure emplc'ed to 'cause the vvaporization4 of the desire distillates, which in turn are fractionally condensed in the condensers 8 2. The hot vapors pass from the chamber 79 into the first condenser 82 which will be made of such cooling ca 'acity as'to condense the heavier intermedli that willthen How to the aplpropriate tank. The uncondensed vapors wil pass from the first gastrap 83 through the tubing 86 into the second condenser which will be of such cooling capacity as 'to condense the lighter intermediate fractions- These lighter intermediate fractions will then discharge from the associated vapor trap 83 and pass `to the appropriate tank and the uncondensedlighter vapors will passover into the third condenser through the'asso'ciated tubing 86. The third condenser will be' of sufiicient cooling capacity to--cause condensation of the low boiling-point fraction whichit is the desire of the refiner to .produce and such fractions will discharge'from the associated vapor trap 83 and pass tothe appropriate tanln The gas may pass from the third gas trapethrough the tubing 89 into the gasabsor r 90 where certain low boiling-point fractions may be recovered, in a manner well understood in the art to which this invention relates.

lt is understood that redistillation and reil'i'inning through the apparatus of the intermediate fractions thus'resulting may be effected' in the same manner as above described for the fractions roduced by the. stills 40.

L' duced.\'by the stills 40. lt is understood that the cooling capacity of the heatinterchanger 27 or any other suitable cooling means may be such that thel temperature of the'liquid hydrocarbons will be reduced from that ruired for cracking to that which will prouce in a single v'aporizing and condensing operation the low boiling point fraction desired; or that after such cooling the temperature will be reduced only enough lto produce by evaporation and fractional condensation the lighter `fractions andone or more of the intermediates above .referred to or the pressure may be so regulated by valves in the exits of the 4f ractionating apparatus and the'reducing valve 44 as to permit of the vaporization of those fractions whose vapor tension is `in Aexcess of the presv down in the chamber 79 maybe drawn off i ate hydrocarbons iso " accepte eure maintained in chamber 79.' The remaining uncondensed vapors will then 'be condensed as above descri edto roduce the low boiling-pointfraction desire Though the Various' fractions may be produced by the fractional condensing described above, there may be, vin ractice, advantages infractionating the hy rocarbons by the fractional distillation operations previously described but the ultimate result is the same which ever ,tractionating operation is employed.

l claim:

1. ln the process tor the production of low boiling-point hydrocarbons,'the combination of steps consisting in heating the hydrocarbons in coils to a temperature sulicient to crack them and under a pressure of not less than 35 atmospheres to prevent vaporization thereof, precipitating thecarbonaceous material of reaction after' thehydrocarbons leave the coils, maintaining t erein a pressure suicient to prevent va orization, substantially maintaimngthe hy rocarbons in their highly heated condition to permit 'ot their substantially complete vaporization upon release of pressure, releasing thepressure and discharging the vaporized' hydrocai-bons into a cooling system and stepping down their temperature to fractionally condense them.

drocarbons to a temperature suilicient to crack them and under a pressure of not less than 35 atmospheres to prevent vaporization thereof, then reducing the rate of flow of the hydrocarbons without any material'reduction in pressure and temperature to permit of further reaction and polymerization, and then reducing the temperature of the cracked hydrocarbons while under this pressure to a degree sullicient to prevent x vaporization of the low boilingoint hydrocarbons when they are discharge at atmosphericl pressure.

3. lin the process for the production of low boiling-point hydrocarbons, the combination` of steps comprising heating the hydrocarbons to a temperature sutlicient to crack them and under a pressure ofnot less than 35 atmospheres to prevent vaporization thereof, and thenreducing the rate of flow of the. hydrocarbons without any material reduction, inpressure and temperature to permitof further reaction and polymerization.

4f. A process for` cracking hydrocarbons comprising forcing the hydrocarbons through heating tubes at a temperature suilicient to crack them and at a pressure of not' less than 35 atmospheres to prevent the vaporization thereof, decreasingthe rate ot flow of the hydrocarbons after leaving the heating tubes and maintaining the hydrocarbons at a cracking temperature and under vent vaporization thereof, t en reducing their rate of flow, and then reducing the sure of not less than 35 atmos )heres to prepressure and vaporizing the hydrocarbons separatmg fractions heavier than gasoline and returning said fractions to thecracking apparatus. l

6'. ln a rocess for the production of low boiling-point hydrocarbons, the .combination of steps consisting in heating the hydrocarbons to a temperature suicient to crack them and under a pressure of not less than 35 atmospheres to present vaporization thereof, then reducing the' temperature of the'y cracked hydrocarbons while undersaid.I

pressure, then reducing the pressure of the cracked hydrocarbons, then immediately stepping up the temperature of all ot the crac ed hydrocarbons to vaporize the hy drofcarbons of diderent boiling-pointsA and then separately cooling the vapors. of dit ferent boiling points.

7. A process of cracking Ahydrocarbons which consists. in passing the hydrocarbons through heating tubes,.subjecting them to a temperature suilicient to crack them and under a pressure and not less than 35 atmospheres to prevent the hydrocarbons from vaporizing. Passing the along at a reduced rate ot flow and maintaining the cracking temperature, also maintaming the ,pressure sufficiently high to prevent the hydrocarbons from vaporizing and then cooling the hydrocarbons while under 'said pressure to a degree sumcient to prevent vaporization when they are discharged at atmospheric pressure.

8. ln the process for the production .ot

hydrocarbons low boiling-point hydrocarbons, the combination of steps consisting in heating fthe hydrocarbons to a, temperature 'suilicient 'to crack them; bypassing them through 'a heating zone then retarding their brate ot dow and maintaining them during a,A prolonged period of time at a cracking temperature and under a pressure not less than 35 atmospheres;` to prevent vaporization thereof, and 'then reducin the temperature of the cracked'hvdrocar ons While under this pressure'to a egree suihcient to prevent vaporization'n-f the low boiling-point hydrocarbons when-they Aare discharged at atmospheric pressure'.

9. llnthelv process for the production of Alow boiling-point hydrocarbons, the combination of .steps consisting in heating the hydrocarbons to a temperature sucient to iso of the cracked hydrocar ons while` under' said pressure, then reducing the pressure sufficiently to permit the lower boiling-point hydrocarbons to vaporize, and then stepping down the temperature of the vaporized 4,hyv droearbons to liquiy thelower boiling-point hydrocarbons.

41(). lln the processfor the production of `low boiling-point hydrocarbons, the combination of steps consisting in heatin thehydrocarbons to a tem erature su cient to crack them reducing t eir rate of iow'and maintainin them at a cracking temperature over a pro onged period of time and yunder a pressure of not lesstban35 atmospheres to prevent Vaporization thereof, then reerature of the vaporizedhydrocarbonsA to liquefy the lower boiling-point; hydrocarbons.

.11. In the processforlthev production ofl low boiling-point hydrocarbons., the combination of steps consisting'in heatirflig4 the hydrocarbons `to a temperature sucient to crack them reducing the rate of flow and maintaining them at a crackingtemperature for a prolonged period of time and--undena pressure of not less than 35l atmospheres to prevent vaporization thereof, then reducing the temperature of -the cracked..hydrocar-' bons while under said pressure, then -redueing the' pressure of the cracked hydrocarbons, then'stepping -up the. temperature of all of the crackedhydrocarbonsto ,vaporize the hydrocarbonsof di'i'erentboiling points and then separately cooling the vapors `o different boiling points.

12. In the process for. theproduction of low boiling-point hydrocarbons, the combination of steps consisting in'lreating the hydrocarbons inf a single passage through a furnace to a temperature sufiicient to crack them reducing' the rate' o f How and maintaining them at a cracking temperature for a pro o prevent Vaporization thereof, 'and reducingv the' pressure suiiiciently to permit the desired hydrocarbons to vaporiz'e.

13. The process of producing low boiling'- point hydrocarbons which comprises the fol- ,the initial cracking point, then passed .through a. larger tube w erein the `vent vaporization of -the nged" period `of time and. under a' .pressure of not less than 35 atmospheres to Maaate through a coilwherein theyV are heated above the initial cracking oint, then ased y I0.- carbons are `kept at a cracking temperature l.for a considerable length of time to facilil A.tate the conversion thereof to the low boiling point hydrocarbons asdescribed. l

14. In the process for the production of 'low boiling point hydrocarbons', the combination of steps consisting -in heating in a,

sin le passage through a furnace the hydrocar "ons to atemperature sufficient to crack them and under pressure of not less than 35 .atmospheres to prevent vaporization thereof; then reducinjthe rate of fi'ow of the cracked hydrocar ons while under said pressure, then reducing the temperature ofthe hydrocarbon, then reducing lthe pressure suiicientlyfto permit the 'lower boilingpoint hydrocarbons tol vaporize and then -condensing them.

ducing the pressure suiiiciently to permit v 'the lower, boiling-point hydrocarbons to vaporize, and then ste ping down the tem-'- 15. I ntheprocess for the production' of low boiling-pointA hydrocarbons, the combination-of stepsfcomprising heating the hy- .drocarbonsv in tubular coils in a single-- passage through a furnace'to a temperature vsufficiently high to crackthem, then transferring the hydrocarbons to a chamber.. of

.relativelylarger cross Asectional area compared to the tubular area Whereintheir rate terial in the tubular coils and permitting' the carbonaceous material to be deposited in able as described.

16.In thegprocess for the production of low boiling-point hydrocarbons, the combination 'of' steps comprising heating the 1%- extent detri- .9.5 of fiow is materially reduced and maintainrod the chamber' of `large cross sectional A4enea -from a"l-1qu1d suspension whereby their 'ac. 'cumulation 1s 1n a condition easily remet'-4 drocarbons in -a'coil to a temperature su cient to crack them and under pressure of not less than 3 5 atmospheres to prevent vaporization thereof, transferring the hydrocarbons tol la tube or chamber of larger cross sectional area, completely filling the larger tube or chamber with hydrocarbons in a liquid state and passing the hydrocarbons through the larger tube or chamber while still maintaining them under pressure to de,

posit the carbonaceous matter andy finally discharging' the undeposited hydrocarbons Afrom the chamber.

.roi-IN o. BLACK.

JWitnesses: i e

GEORGE H. HILEs, L. BELLE Wnavaa.

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