US1431772A - Process and apparatus for treating hydrocarbons to produce those of lower boiling points - Google Patents

Description

1. c. BLACK. PROCESS AND APPARATUS FOR TREATING HYDROCARBONS TO PRODUC THOSE 0F LOWER BOILING POINTS.

APPLICATION FILED ALG.|5, I92I.

Patented Oct. 10, 1922.

Patented Oct. 1 0, 1922.

JOI-IN C. BLACK, 0F DESTREHAN, LOUISIANA.

PBCESS APPARATUS FOR TREATING HYDRAOCARBONS T0 PRODUCE THOSE OF LOWER BOILING POINTS.

Application led August 15, 1921. Serial No. 492,377.

To all whom it may concern.'

Be it known that I, JOHN C. BLACK, a citizen of the. United States, residing at Destrehan, in the parish of St. Charles and State of Louisiana, have invented a certain new and useful Process and Apparatus for Treating Hydrocarbons to Produce Those of Lower Boiling Points, of which the following is a specilication.

This invention relates to the dissociation or conversion of high boiling-point hydrocarbons derived from crude petroleum or its equivalent, into those of lower boilingpoint, and to an apparatus especially useful in increasing the production of, so-termed, asoline ,from relatively heavy hydrocarons having high boiling points. It 1s known that by the apparatus and processes at present employed for producing i; out cracklng, a comparative y centage, from a fraction of asoline Withsmall perone per cent to thirtyV per ce-nt or more gasoline, is obtained by ordinary distillation of the crude oil.

The apparatus in vogue for Uhan that pro lation of the "rude oil, rel

and processes commonly roducing gasoline, other ucedy by ordinary distilfundamentally upon heating the hy rocarbons to certain temperatures produce cracklng,

under pressure to taking the `vapors oli at a high temperature under the pressure employed and condensing the Same.

As distinguishing fundamentally from such pressure-vapor processes. my present apparatus performs what, for

brevity, may be termed a pressure-li uid proce, since I do not vaporizc the ydrocarbons to a ny material A degree while at cracking temperature, but

rather, maintain a pressure on carbons above the vapor pressurethereofthe hydroat the cracking temperature emplo ed,

then reduce the body of hydrocarbons,

the pressureemployed, to such temperature of the wV while they are under ole a point as may `be desirable for subsequent treatment thereof. If the llydrocarbons, are reduced to nor as` treated,

al temperature they will have the appearance `of crude oil with many of its characteristics and termed a crude equivalent.

Infthis improved apparatus maintain pressure on the hydro they may be lI not only carbons uning, dissociation .this by dischargin V cent, more or less.

der treatment to prevent any material vaporlzation thereof, but I preferably main-V ta1n them at cracking temperatures While in liquid form for a prolonged period of time and retard How of the liquld hydrocarbons while at cracking temperature so that dissociation and polymerization will be as complete as possible before the hydrocarbons are cooled or subjected to the subsequent treatment required to separate the low boilin from the high boiling hydrocarbons. Ig maintain pressure on the hydrocarbons under treatment until they are cooled if the immediate object is to crack and store the product for subsequent 'treatment as hereinafter described. If, however, it is desired to crack and then immediately distill, pressure is maintained on the hydro carbons under treatment during the crackand polymerization/of the hydrocarbons, after which distillation of the hot hydrocarbons at atmospheric or higher pressure will be effected in any suitable distilling and fractionati apparatus, two examples of which Willne described hereinafter.

4 To maintain the liquid hydrocarbons at cracking temperatures for the prolonged period of time and at the same time to cause the deposition of carbon produced by the cracking operation, I preferably reduce the speed of iow of the liquid hydrocarbons while they are at the cracking temperatures and, in this particular instance, I'accomplish the heated hydrocarbons from the crac ing or lieatin coil into a digester, as I term it. This igester is a combined cracking chamber and carbon catcher of larger cro sectional area than that of the cracking coil tubes.

In the operation of my apparatus, I may treat for the production of gasoline the intermediate cuts, resulting from first sub- 'acting crude petroleum or a crude equivalent to any o f the heretofore known distillation' processes. By such first distillation process there may result, for example, gasoline amounting 1n volume to' from 15 to 20 'per cent* more or less; asphalt, coke and the ike, 2() per cent; and intermediates, 65 per The percentages given approximate and may vary conwith petroleum from differentloare on] siderab y calities. These intermediates, when treated in my apparatus, are changed into a crude equivalent which is then fractionated at once in the a paratus to separate the fractions or cuts desired, or allowed to stand in storage for a time and then fractionated. It is understood that the fractionating may be performed in any suitable apparatus other than disclosed in the drawings. An advantage that arises in not fractionating immediately is that the yield of lighter hydrocarbons is thereby increased.

The accompan ing drawings illustrate an apparatus embo ying the invention:

Figure 1 is a more or less diagrammatic elevation, partly in section, of the apparatus; and

Figure 2 is a sectional elevation on line indicated by rc2-w, Figure 1.

The apparatus illustrated in the drawmgs is constructed as follows: In a furnace A there is provided a suitable lower combustion chamber 1 having at one end thereof a burner 2 and having at its opposite endl an opening 3 through which the products of combustion can pass into a coil-heating chamber 4. In .the coil-heating chamber 4 is a cracking coil 5 which is heated by the products of combustion` that pass through the chamber 4. `The coil-heating chamber4 is provided at the end opposite that having the opening 3 with an opening 6 through which the products of combustion escape into an upper combustion chamber 7 provided 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 .heatedadditionally by fire vfrom the burner 8.

From the combustion chamber 7 the products of combustion iiow through-an opening 9 into an intermediate coil-heating chamber 1() having a pre-heating coil 11. The roducts of combustion flow from the chamber 1() through an opening-12 into an upper coil-heating chamber 13 in which is positioned a heating coil 14. From the chamber 13 the products of combustion discharge through a flue 15. The fuel furnished to the burners 2, 8 may be as or oil and the burners are ca able of ralsing the various chambers to t e temperatures required for performing the process in the apparatus.

The coils 5, 11 comprise a number of straight tubes 16 which pass through per forations 17 in the front-and rear walls of the chambers 4, 10. The coils 5, 11 further comprise headers 18 connecting the ends of adjacent tubes to one another. The headers 18 are provided with removable plugs 19. Thus itis 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 `closures therefor.

so that 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 the coil 5 is connected by a tube 21 to a digester or combined cracking chamber and carbon catcher 22, preferably o'flarger cross` sectional area than the cracking tubes 16. The digester 22 may be formed of a piece of relatively large tubingr and removable heads 23 are fitted to the opposite ends of the tubing to form tight The heads 23 are detachably held in place by okes 24 and screws 25. Connected with tie digester 22 is a blow `oli' line 94 which is provided with a valve 95 and which may be connected to a receiver, not shown.

The digester 22 is connected by a tube 26 to a heat nterchanger 27, said tube 26 being connected with the inner tube 28 of the interchanger, The outer tube 29 of the interchanger is connected by tubing 3() 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 of the coil 11 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 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 through a supply pipe 36 connecting with a tank 37. The tubing 34 is provided with a pressure gage 38. A by-pass 96 connects the tubing 30 to the tubing 34 and is provided With a valve 97 so that the heat interchanger may be cut in and out at will.

r The inner tube 28 of the heat interchanger is connected by tubing 39 to one or more fractionating stills 40 of any desired construction. When more than one still is employed, the stills are connected to one another by cross-overs 41 yforcontinuous operation provided with pressure regulator and discharge valves 98. 1f so desirecheach still may be operated independently of the other, each receiving its supply of oil from 39 through the valve 43, the cross-overs 41 being blanked oil'. The stills are each provided with a vpressure gage 99. 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 oni the` liquid hydrocarbons in the cracking coil 5 and cracking chamber 22 andalso in all other parts of the apparatus between the pressure regulator and the pump 35. The tubing 39 is also preferably provided with` a carbon catcher 100 having a discharge pipe 101 controlled by a valve 102.

Each still 40 is connected by tubing 45 to a condenser 46 and each tubing 45 is provided with a pressure regulating discharge valve 103. Each condenser is connected by a tube 47 to a vas trap 48; each gas trap 48 is connected y tubing 49 to a gas absorber 50 and the gas absorbers are provided with as vent pipes 51 to carry the gas to any esired 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 of the storage tanks 55, in this instance, two of them, are connected by tubing 56 to the tubing 36. The tubing 56 is 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 62 is provided with a pressure regulator 64` and a pressure gage 65 between the pressure regulating valve and the cooler. Also the tubing 62 is preferably provided between the valve 64 and gage 65 with a carbon catcher 104 having a discharge pipe 105 controlled by the valve 106. The gas trap 63 is connected by tubing 66 to a as absorber 67 and the gas absorber is provided with a gas vent tube 68. The gas t-rap 63 is connected by tubing 70 to a storage tank 71. The tubing 60 is provided with a valve 72 and the tu ing 39 is provided with a pressure gage 73. To the tubing 70 is connected a tubing 74 having a valve 75, and the tubing 74 connects with the tank 37. The tubing 70 is provided between the tubing 74 and the tank 71 with a valve 76. The tubing 34 is provided with a valve 107 between the bypass 96 and heat exchanger 27.

, The process described and claimed in my co-pending application filed December 12, 1919, Serial No. 344,406, 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 I preferably use the intermediate fractions resulting from treating crude petroleum or a crude equivalent, by rior known processes. Among such nterine iate fractions, for example, are those which are not capable of being further cracked by the relatively lowpressure processes to produce `the much desired low boiling-pointhydrocarbons. The valves 59, 72, 75 and 107 are opened and valves 42, 58, 76 and 97 are closed andthe pump 35-is operated to force liquid hydrocarbons from the tank 37 through the system and to produce 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 filled with the liquifd hydrocarbons which are to be treated. Air mgzy be Vexi ff pelled from this portion of the system throu h the tank 37. The res are then starte at the burners 2, 8 so4 as to heat the coils 5, 11, 14 to the required temperatures.

The pump is continued in operation and the hydrocarbons circulate continuously while they are bein heated to the required temperature. 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 through the cracking tubes and di ester. The pyrometers 20, 32 will be consu ted to determine the temperature of the hydrocarbons in the coils 5, 11. The temperature of the coil 11 will be preferably maintained just under thatrequired for cracking of the hydrocarbons, though if the temperature should rise higher and an incipient .cracking of the oil take place the tubes may be readily cleaned of carbon deposits When they become choked. The coil,

5 is heated to a predetermined cracking temperature.

The degree of pressure employed is predetermined for the particular hydrocarbons bein treated. The temperature required for t e particular hydrocarbon being treated may be determined by theJ increase of gravity of a sample, sup lemented usually by a distillation test to i etermine the yield of hydrocarbons boiling between certain specie temperature limits.

Assuming that one or more of the stills 40 is to be utilized, that the predetermined cracking temperature has been reached, and that the regulator 44 has been set for the predetermined operating pressure, the valves 42, 43 77 will be opened and the valves`58, 72 will be closed, thus causing the hydrocarbons to flow into the stillor stills when the desired degree of cracking is reached. The pum 35 1s continued in operation so as t0 maintain the desired pressure rearwardly of the pressure regulator 44 and so as to cause the hydrocarbons to How :uifde'r such pressure through the various coils and through the cracking chamber 22. The pressure prevents any material vaporization in the cracking coil 5 and digester 22, though it may be possible that some of the lightest of the hydrocarbons may va orize under some of the pressures which may desire to use in the apparatus. Before the liquid hydrocarbons discharge from the cracking coil 5 they reach-'the cracking temperature and the time 'of subjecting the liquid hydrocarbons to the cracking temlperature is prolo ed by reason of the li uid ydrocarbons disc arging from the coilx through the tubing 21 into the digester 22. In the'di ster 22 the rate of' liow of the 1i' id h rocarbons decreases because of the re ative y large cross Sectionalarea of the digester. The digester, 22 is suitably insulated against loss of heat and thus the liquid hydrocarbons are maintained at cracking temperature during their flow through the digester.

Not only docs the digester 22 prolong th(l cracking operation so as to insure that the cracking of the liquid liydrmaarbons at the given tcniperature is complete 0r substantially complete; but deposition of carbon occurs in the digester to a much larger cxtent than in the coil 5, for the reason that the flow of liquid hydrocarbons is slower in the cracking chamber than in the coil 5, thus permitting the free carbon produced in thc cracking operation to become attached to the relatively large ivall area of the digestel'.

From the digester 22 the cracked hydrocarbons, still in the liquid state at couiparatively high temperature, flow through the heat interchanger 27 Where they are cooled to a greater or less degree, depending upon the area of the radiating surface of the heat interchanger. Thus a predetermined amount of heat is absorbed in the interchanger by the cooler hydrocarbons being fed into the system by the pump 35, and the heat interchanger serves to initially heat the hydrocarbons being treated. Further heating of the hydrocarbons is ell'ected, between the heat interchan'ger 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 inter-changer 27 may be such a's to cause those hydrocarbons which are liquids at ordinary temperatures and pressures to remain liquid when the artificial pressure is entirely removed. That is to say, if itis not desired to immediately fractionate the cracked hydrocarbons, they may be discharged into the tank 71 by opening thevalves 72, 76 and closing the valve 42; that, if the cooling capacity of the interchanger 27 be suflicient, the lighter as well as the heavier h drocarbons in the crude equivalent will `ischarge as liquids without running them through supplemental cooling means; and that, if the cooling capacity of the interchanger is not salti-cient to prevent vaporization olf the cracked hydrocarbons upon release of the presspre through the valve'64, then the cooler 61 will be operated to complete this cooling operation. I have discovered that, by allowing the crude equivalent to stand for a more or less extended period of time to rmit 'of further polymerization in the tank 1 before fractionating upon subsequently fractionating the crude equivalent it yields a greater percentage of the more stable lighter hydrocarbons desired, hence the advantage of immediately cooling the cracked hydrocarbons to a temperature sufficiently low to revent vaporization of 2all, of them and pro ucc the mixture which is termed a crude equivalent. When, however, the valve 42 is open and valves 72, 76 closed the hydrocarbons are treated at once in the still and hence it will not be necessary or desirable to cool them to ordinary temperatures, and consequently less fuel will be required in the stills 4() to effect distillation. If it be not desired to ef feet cooling of the cracked hydrocarbons by operation of the heat intel-changer 27 the incoming hydrocarbons may be by-passed by closing the valve 107 and opening the valve 97.

The liquid hydrocarbons, after parting with at least some of their heat: in the intel-changer, 27, will discharge into the first still 4() and the first cutor lightest vapors will be carried over into the associated condenser 46. If continuous distillation is employed the unvaporized heavier hydrocarbons will flow from the first still into the second still through the cross-over 41 and another cut will be made and the seco-nd cut vapors will discharge into the associated condenser. Also from the second still the yet heavier unvaporized hydrocarbons will discharge into the third still through the cross over 41 and the third cut vapors taken off from the third still will discharge into the associated condenser 46. Vhatever as remains after the vapors pass throught e condensers will pass into the absorbers 50 and may b e recovered in part in a manner Well understood in the art to which this invention relates. To achieve the distilling just described the stills will, of course, be progressively heated from left to right.

It will be understood that not only are the stills 4() progressively heated, but that, if desired, the pressure may be progressively 'reduced or stepped down in the stills from left to right by proper adjustment of the valves 98, 103 and of the draw-oli' valve 109 on pipe 110 discharging from the last still 40, the stills thus constituting expansion or vaporizing chambers. This enables me to vaporize the various light fractions while they are still under pressure, thereby preventing to a large extent the production of olefines yand unsaturated hydrocarbons. Of course, if desired, this fractionating by step,- ping down the pressure may be elfected without applying heat to the stills 40, for by properly adjusting the valves 98 and 103 only those hydrocarbons whose vapor tension or pressure is equal to or in excess of that imposed by the valves 98 and l103 will vaporize and escape to the respective con-V densers. The residue that accumulates in the Iirst and second expansion chambers passes therefrom into the next succeeding chambers 40, respectively, under lower pressure so that the second and third cut hydrocarbons will vaporize and be condensed in the associated condensers. Any number of chambers may be utilized for vaporizing under reduced pressures each one giving a different fraction, depending u on the pressure and temperature of the iydrocarbons entering the different vaporizing chambers.

The condensates pass from the condensers 46 through the tubing 54 into the storage tanks 55. In this instance, the lighter oi' lower boilingr point hydrocarbons, which it is the desire of the refiner to recover, are given ofi in the first still, the inteiinediate fractions are given off in the second and third stills and the cai'bonaceous matter or residue is deposited in the third still. It may be assumed, for example, that the condensate from the first still is approximately 56 Baume, that the condensate from the second still is approximately 350 Baume and that the condensate from the third still is approximately 200 Baume. These heavier o roducts or intermediate fractions produced in the second and third stills will be discharged from time to time from the storage tanks 55 containing them through the pipe 56 into the pipe 36 by opening the valves 58 and closing the valve 59, thus permitting the pump 35 to force the intermediate fractions 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, may be re-run independently through any suitable still for re-distillation so as to separate the lighter fractions from the heavier, and such li hter fractions maythen be thrown in Wit the distillates from thefirst still and the heavier fractions may be stored and then re-iun through the igiparatus.

If it be not desired to distill the liquid cracked hydrocarbons at once, the valves 42, 75 will be closed and the valves 72, 76

opened, and the liquid cracked hydrocar-V bons will then flow from the tubing 3'9 through the tubing 60 into the cooler 61l This cooler 61 may be dispensed with if the heat interchanger 27 is made of sufficiently great' cooling ca acity to absorb substantially all of the 'eat artificially applied to the hydrocarbons. The cooler liquid hydrocarbons pass from the cooler 61 through the tubing 62 and pressure regulating valve 64 into the se arator 63 and the liquid hydrocarbons ow from. said separator through the tube in to the storage tank 71. The hydrocarbon in the storage tank 71 is termed a crude equivalent since 1t resembles to a large degree crude petroleum. This crude equivalentat any desired time after its production will be fractionated to segregate the low boiling-point hydrocarbons desired from those of higher 'boilingpoint.

Though the above described process performed in this apparatus d lil'ers considerablyv from the process of refining erude petion of low known low pressure prcessesthere is troleum oil patented t0 Goor e L. Benton May 25, 1886, No. 341,564, an though said enton process was conceived for the purpose of producing'l a different product, namely an illuminating oil, than the foregoing described apparatus produces, I employ the relatively high temperatures and pressures of the Benton process. in the cracking operation; but, instead of spraying the hy rocarbons at cracking tem erature into'a vaporizing chamber to pro uce the homogeneous illuminating oil of the Benton process, I effect a prolonged cranking operation under pressure, reduce the rate of flow of the liquid hydrocarbons 44while at cracking temperatures, then reduce the temperature of the cracked liquid hydrocarbons to or below the vaporizin temperature of the low boiling-point hy rocarbons which it is desired to recover, and finally frac tionate the hydrocarbons thus reduced in temperature.

Ihave discovered that the yield of low boiling point hydrocarbons is very materially increased by prolongation of the heat and pressure necessary for cracking, and I obtain this prolongation in the apparatus illustrated by use of the digester 22, which also, as had been noted above, reduces the rate of lio-w of the liquid s ream. In this manner I am enabled to p duce a greater volume of low boiling point hydrocarbons from a given quantity of crude petroleum or a crude equivalent than is possible by prior known 12processes and in prior known apparatus. or this reason the process is very useful and valuable since the' producboiling point hydrocarbons such as gasoline by present known processes can scarcely keep pace with the increasing demands. therefor, mainlyl as fuelfor internal combustion motors'i ,Also by prior roduced 'an intermediate fractionwhich,p byv former known processes and a paratus, could not be cracked, and which I am enabled by this process to crack to v high grade gasoline. I prefer to treat any ofthe intermediate fractions in this apparatus, ratherthan crude oil, because the prior distillation removes a large amount of carbonaceous .material which thus cannot act to foul the apparatus. The hydrocarbons of relatively high' boillng point produced in the second and 'third Stills in this Instance, will referably re- I'lin through the apparatus ai'idiiracked, and

for this 111 08e 'when iiantities4 of the relatively iglil bcii q ling oint hydrocarbonsv have been produced by tiie still, the valve 59 Willjbe closed and the valves 58 will be opened to rmit the car v ns tlil'bllg the system for racking and redistillatlnrom this it is lear that in this apparatus the process may be a continuproduce lln'lp 35V to force such hydroous one, not only in the sense that new supplies of oil are constantly being treated, but that a relatively large proportion of the product is re-run from time to time to eventually crack the relatively high bo1l1ngpoint hydrocarbons circulating nthrough the apparatus, thus enabling the production of possibly 5() per cent or more of lovvn b oiling-point hydrocarbons from the orlgmal stock treated.

The fractionating may be accomplished in any other suitable apparatus than described above, and, as an example of another fractionating apparatus which may form a part of the system, I may' fractionate them by running them through fractional condensers, and for this urpose I have shown in the drawings a istillation vaporizing chamber 79 which is connected by tubing 80 to the tubing 39 between the pressure regulating valve 44 and a valve 77 on the tubing 39. The chamber 79 is connected by tubing 81 with the first 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 With sampling boxes 85. The vapor trap 83 of the first condenser is connected with the coil of thesecond condenser, and the vapor trap of the second condenser is connected with the coil of the third condenser by tubings 86, respectively. Each of the sampling boxes 85 is connected by tubing 87 to a suitable receptacle or tank, the tubes 87 being provided with valves 88, respectively. For example, the discharge pipe 87 of the first condenser 82 "may be considered as being connected with the first tank 55 beginning at the left in Figure 1 of the drawings, the tubing 87 of the second condenser as being connected with the second tank 55, and the tubing 87 of the third condenser as being connected with the tank 55 at the right side of Figure 1. These connections with the tanks 55 are not shown since it would tend to conge t the drawing to show them, but it is unerstood such connections exist so that the heavier and lighter intermediate fractions from the first and second condensers 82 may be readily re-run through the apparatus for re-cracki'np in a manner hereinbefore described. The gas trap of the third condenser is connected by a tube 89 with a gas absorber 90 provided with a vent pipe 91. A pipe 92 havin a valve 93'discharges from the chamber 7:9. i

Preferablythe tubes 81 and 86 are provided, With pressure regulating and discharge valves 108 so that, by the roper adjustment thereof together with va ves 88, 93 and valve 111 on tube 89, the pressure may be stepped down from the chamber 79 to the first condenser, from -the first to the second and from the second to the' third; thereby controlling not only the temperature of the hydrocarbons in making the various cuts, but also predetermining the pressure at which the out is made. Thus, instead of maintaining the cracked hydrocarbons at the cracking pressure while condensing, or reducing the pressure to atmospheric while condensing, or condensing all of the cuts at any pressure between that of cracking and atmospheric, all of which arc made possible by proper adjustment of the valve 44, the condensing in the different condensers 82 may be effected at different pressures by proper adjustment of the valves 108, 88, 93 and 111.

In order to fractionally condense lthe craclked hydrocarbons, the valve 77 on the tubing 39 will be closed, as well as the valve 72, and the valve 7 8 will be opened, thus allowing the hot liquid hydrocarbons discharging through the pressure regulator 44 to vaporize in the chamber 79. The tarr'y products or other carbonaceous matter thrown down in the chamber 79 may bc drawn off through the pipe 92. It is understood that the temperature of the hydrocarbons in tubing 39 and connecting tubing 80, will be sufficiently high under the pressure employed to cause the vaporization of the` desired distillates, which in turn are fractionally condensed by proper regulation of the appropriate valves. The hot/vapors pass from the chamber 79 into the first condenser 82 which will be made ofsuch cooling capacity as to condense the heavier intermediate hydrocarbons that will then flow to the appropriate tank. The uncondensed vapors will pass from the first gas or vapor trap 83 through the tubing 86 into the sec ond 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 approprlate tank and the uncondensed lighter vapors will pass over into the third condenser through the associated tubing 86. The third condenser Will be of suicient cooling capacity to'cause condensation of the low boiling-point fractions which it is the desire of the refiner to produce and such fractions will discharge from the associated vapor trap 83 and pass to the appropriate tank. The gas may pass from the third gas trap through the tubing 89 into the gas absorber 90 Where certain low boiling-point fractions may be recovered, in a manner Well understood in the art to which this invention relates.

By appropriate adjustment of the pressure dregulating valves 108, 88, 93' and 111 to step down the pressure, sudden release of pressure while the hydrocarbons art at high temperature is avoided and the different cuts may be made sofas tolprevent in great measure the production of olefn'es and. unsaturated hydrocarbons which might result if the pressure were wholly or almost completely released while the oil is Still at crackin temperature. Thus I am enabled to avoid low pressure cracking which tends to produce olefines and unsaturated hydrocarbons.

It is understood that re-Jdistillation and re-running through the apparatus of the intermediate fractions-thus resulting may be effected in the saine manner as above described for the fractions produced by the stills 40. The same cuts or fractions may be produced in ythe series of condensers 82 as are produced by the stills 40. It is understood that the cooling capacity of the heat interchanger 27 or any other suitable cooling nie-ans may be such that the temperature of the liquid hydrocarbons will be reduced from that requiredfor cracking to that which will produce in a single vaporizing and condensing operation the low boiling point fraction desired; or that after such cooling the temperature will be reduced only enough to produce by evaporationl and fractional condensation one or more of the intermediates above referred to` The remaining uncondensed vapors will then be condensed as above described to produce the low boiling point fraction desired. Though the various fractions may be produced by the fractional condensing described above, there may be, in practice, advantages in fractionating the hydrocarbons by the fractional distillation operations previously described, by fractionating` towers or other apparatus, but the ultimate result is in a measure the same whichever fractionating operation is employed.

The cracking operation is continued in the coil 5 and crackin chamber 22 until the increasing differential pressure between the gages 38. 73 or 38, 65, as the case may be, denotes such increased resistance to the flow of the oil as to indicate that said coil or the digester 22 is seriously fouled with carbon, rendering the apparatus inoperative; where upon the fires are shut off and the fouled tubes 16 and digester 22 are cleaned, the cleaning operation being facilitated by removal of the plugs of the headers and the heads 23 of thedigestef, thus to allow each .tube and the digester to be separately cleaned of the carbon deposited therein. Or, before differential pressure occurs, cleaning may be effected by blowing out with air or steam or both.

The higher the temperature and longer the time employed for cracking the hydrocarbons the larger will be the yield of low boiling-point hydrocarbons and the greater will be the production of carbon, so thatin a practical commercial plant it is necessary for the operator to choose such a temperature and pressure and duration of such temperature and pressure that as longr a run as possible may be maiie, Without the necessity of cleaning out the carbon, consistent with a suflicient yield of gasoline to make the operation of the plant profitable.

The rocess may be better understood by a sIpeci c example, as follows:

have operated with my process on an oil that begins to crack at about 750 F. but ordinarily producing 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 F. the yield of gasoline was as high as 30% of the original stock employed. This latter temperature may be too high in practice to make the process profitable and the refiner might have to be contented with a lower yield but longer running time, the decreased cost of operation of the longer running time compensating for the lower yield.

It is of paramount importance that the pressure employed in this process be suiiiciently high to, prevent vaporization of the oil in the tubesl, excepting, possibly, to an inconsiderable, and negligible degree, since such vaporization would cause rapid deposition of carbonaceous material in the tubes and consequent quick fouling thereof. In practice I have successfully employed, and prefer, a pressure of at least 60 atmos heres and as hiUh as 1,000 to 1,200 poun s per square inci and even higher for `some oils. The pressure to be employed is dependent in a reet-measure upon the character of the oibeing treated and the temperature to which it is necessary to raise the oil in the cracking operation, since the higher the temperature employed the greater the pressure required to prevent any substantial vaporization of the oil.

It is to be noted that the reduction in temperature of the cracked liquid hydrocarbons to or below the vaporizing temperature of the low boiling-point hydrocarbon 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. Bentons process enabled him to increase the produc-` tion of illuminatin oils and decrease the production of benzine, while by the operations performed in my apparatus the production of gasoline is increased and that of the less valuable intermediate fractions is decreased. This result is effected in the apparatus shown by employing cracking temperatures of from 750 F. to 1,200o F., or even higher for some oils. and pressures in excess of 500 pounds per square inch.

4A broad process that can be performed in this apparatus is not claimed herein but is the subject of my co-pending a. plication filed December 12, 1919, Serial o. 344,406 the process claims in this case being limited to a feature not disclosed in my cti-'pending application.

I. am aware that the mere cracking of liquid hydrocarbons under pressure is not new and also that to merely cool the cracked h drocarlions while li( uid is not new. Iienchelle in his British atent No. 6547 of 1914 and Renard in his French Patent No. 462,286 of November 19, 1913, both disclose these two steps. However, Fenchelle does not cool the cracked hydrocarbons to Va temperature sufficiently low to prevent vapor ization of the lighter hydrocarbons when the pressure is released. But my apparatus can be operated t0 cool the cracked hydrocarbon while in liquid form to a temperature below the vapor tension of the lighter hydrocarbons so as to obtain in liquid form the lighter as well as the heavier hydrocarbons, the hydrocarbons of different boiling points forming, in this instance, a mechanical mixture which may be allowed to stand for a week or two for more complete polymeriza- 'tion so as to increase the yield of low boiling point hydrocarbons. This mixture or crude equivalent cansubsequently be fractionated in any suitable apparatus. Furthermore my apparatus can be operated to prolong the cracking operation with its resultant increased yield of low boiling hydrocarbons and also to promote polymerization of the unstable hydrocarbons, such reaction being very rapid under the prolonged heating secured in the, digester. In conjunction with this, tihe deposition of carbon will take place in a chamber that can be readily cleaned of carbon and polymerization products. This is my second operation and it precedes the cooling or the fractionating operation of other patentees. disclosed herein can be o erated to immediately fractionate the hy rocarbons as soon as the cracking is effected, thus conserving heat. In another instance the apparatus operates to cool the cracked liquid hydrocarbons sufficiently to prevent vaporization of the heavier, but not the lighter, hydrocarbons when the pressure is subsequently released, and then the apparatus operates to ste down the temperature to separate the hy rocarbons of di'erent boiling points, one at a time, This may be done at atmospheric pressures, or under pressures greater than atmos heric and less than the vapor tension of t e hydrocarbons which it is the object of the rener to obtain. It has also beenv seen that the apparatus can operate to fractionally condense b stepping down the pressures as Well as t e temperatures; so that the condensing Yoccurs under predetermined pressures as well as temperatures. In still another instance the apparatus operates to cool the cracked liquid hydrOQrbons suicientl to maintain the heavier hydrocarbons ,1n a liquid state while permitting the lighter hydrocarbons to vaporize when' the pressure -is subsequently reduced to atmos- The apparatus pheric or to a pressure between atmospheric and the vapor tension of the hydrocarbon which is to be obtained. The apparatus then operates to step up the temperatures to vaporize the heavier hydrocarbons of different boiling points, one at a time. This distilling may be effected at atmospheric pressures, or under pressures greater than atmospheric and less than the vapor tension of the hydrocarbons which are to be produced. The apparatus can also operate to fractionate the hydrocarbons by stepping down the pressures without the addition of heat, the first lowering of pressure permitting the heaviest fractions to condense, ,the second lowering of pressure permitting the intermediate fractions to condense, and so on.

I claim:

l. In an apparatus of the character described the combination of a furnace, a cracking coil in the furnace, means connected with the cracking coil to maintain the hydrocarbons at cracking temperature, said means also decreasing the rate of flow of the hydrocarbons after leaving the cracking coil, a pipe line connected therewith and having a discharge end, a valve located on the line between the ,cracking coil and the said discharge end and means to roduce sufiicient pressure on the hydrocar ons to prevent vaporization thereof while at cracking temperature.

2. In an apparatus of the character de` scribed, the combination of a furnace, a cracking coil, a digestor of larger cross sectional area than the cracking coil connected therewith, said digestor having a removable end for cleaning purposes, a pipe leading from the digestor and havin a discharge end, a valve located on the Iine between the dlgestor and its discharge end, and means for sup lying hydrocarbons to the coil, digestor and) ipe vline to said valve and for keeping the iydrocarbons as they pass to the said valve through the coil, d1- gestor and pipe line, under suicient pressure to maintain them in a liquid condition.

3. In an apparatus of the character described the combination of a furnace, a cracking coil in the furnace. a di estor of larger cross sectional area than t e cracking coil connected therewith a fractionating apparatus, a pressure regulating valve between the digestor and fractionating apparatus, andmeans for supplying hydrocarbons to the coil and digestor under pres',- sure and maintaining a sufficient pressure in the system against the regulatin valve to prevent vaporization of the Yhy recarbons. v he 4. In an apparatus of the character described, the combination of `a furnace, a cracking coil in the `furnace, a vaporizing chamber, a plurality of fractionatmg condenser coils in series relation with eachl other, tubing connectin the vaporizing chamber with the crac ing coil, cooling means for the tubing, a pressure regulating discharge valve on the tubing between the vaporizlng chamber and the cracking coil, and means for supplying hydrocarbons to the cracking coil and for passin the hydrocarbons through the coil and tu ing to said discharge valve under suflicient pressure to maintain them in a liquid condition as described. i

5. In an apparatus of the character described, the combination of' a furnace, a cracking coil in the furnace, a plurality of vaporizing chambers in series relation with each other, ressure regulating discharge valves for said chambers, tubing connecting the first of said chambers with the cracking coil, Crossovers between adjacent chambers, pressure regulating dischar e valves on the crossovers, a pressure regu atin discharge valve on the tubing between t e cracking coil and the first Vaporizing chamber, and means for supplying hydrocarbons to the cracking coil and for passing the h drocarbons through the cracking coil un er suiicient pressure to maintain them in a liquid condition as described.

6. In an apparatus of the character described, the combination of a furnace, a cracking coil in the furnace, a plurality of vaporizing chamber in series relation with each other, pressure re ulating discharge valves for said chamiers, tubing connecting the first of said chambers with the cracking coil, cooling means for the tubing, Crossovers between ad'acent chambers, pressure regulating disc arge valves on the crossovers, a pressure re lating discharge valve on the tubing etween the chambers and the tube-cooling means and means for supplying hydrocarbons to the cracking coil and for passing the hydrocarbons through the cracking coil under suicient pressure to maintain them in a liquid condition as described.

7. In an apparatus of the character described, the combination of a furnace, a cracking coil in the furnace, a lurality of fractionating stills in series relation with each other, ressure regulating discharge valves for said stills,l tubing connecting the first of said stills with'the cracking coil, cooling means for the tubing, Crossovers between adjacent stills', a pressure regulating discharge valve on the tubing between the cooling means and the first still, and means for supplying hydrocarbons to the cracking coil and for passing the h drocarbons through the cracking coil un er sufficient pressure to maintain them in a liquid condition as described.

8. In an apparatus of the character described', the combination of a furnace, a cracking coil in ,j the. furnace, a digestor, a

plurality of connected fractionating condensors in series relation to each other, a vaporizin chamber, pressure regulating discharge va ves for sind condensors, pressure regulating discliarge valves on the connections between adjacent condensors, tubing connecting the digestor with the va orizing chamber a pressure regulatin discharge valve on the tubin between t e Vaporizing chamber and tiie digestor, and means for supplying hydrocarbons to the cracking coil and digestor and for assin the hydrocarbons through the Cracking coi and digestor under suflicient pressure to maintain them in a liquid condltion as described.

9'. In an apparatus of the character described, the combination of a furnace, `a cracking coil in the furnace, a digestor, a vaporizing Chamber, a plurality of connected fractionatlng condensers in series relation with each other, pressure regulating dis- Charge valves for said condensors, pressure regulating discharge valves between adjacent condensors, tubing connecting the vaporizing chamber with the digestor, cooling means for the tubing, a pressure regulatlng discharge valve on the tubing between the vaporizing chamber and the tube cooling means, and means for supplying hydrocarbons to the cracking coil and digestor and for passing the hydrocarbons through the cracking coil and di estor under sufficient pressure to maintain iem in a liquidcondition as described.

10. In an apparatus of the character described, the combination of a furnace, a cracking coil in the furnace, a plurality of fractionating stills in series relation with each other, pressure regulating discharge valves f'or said stills, crossovers between adjacent stills, pressure regulating discharge valves on the cross overs, tubing connecting the first of the stills with the cracking coil, a pressure regulating discharge valve on the tu ing between the rst still and the cracking coil, and means for supplying hydrocarbons to the cracking coil andforl passing the hydrocarbons through the cracklng coil under sufficient ressure to maintain them in a liquid condition as described.

11. In 1an apparatus of the character described, the combination of a furnace, a`

cracking coil in the furnace, a plurality of fractionating stills in series relation with each other, pressure regulating discharge valves for said stills, Crossovers between adjacent stills, pressure regulating discharge valves on the crossovers, tubing connectin the-first of the stills with the cracking coi cooling means for the tubing, a pressure regulating discharge valve on the tubing be- 'tween the first Still and the tube-cooling means, and means for supplying hydrocarbons to the cracklng coil and for passin the hydrocarbons through the cracking coi under sufficient pressure to maintain them in a liquid condition as described.

12. In an apparatus of the character described, the combination of a furnace, a cracking coil in the furnace, a digester of larger cross sectional area than the cracking coil connected therewith a vaporlzing chamber, a series of connected fractionating condensers, pressure regulating` discharge valves for the condensers, messure regulating discharge valves on th' connections between adjacent condens'e'rs, tubing connecting the vaporizing ,chamber with the digester, a pressure.4 regulating discharge valve on the tubing between the vaporizing chamber and 'the digester, and means to pump hydrocarbons into the cracking coil.

13. Inan apparatus of the character described, t-he combination of a furnace, a cracking coil in the furnace a digester of larger cross sectional area than the cracking 'coil connected therewith, a series of fractionating stills, pressure regulating discharge valves for the stills, crossovers between adjacent stills, pressure; regulating discharge valves on the crossovers, tubing connecting the first of the stills with the di ster a ressure re lating dischar e vigile ori theptubin bet'lieen the first stigll and the digester, an means to pump hydrocarbons into the cracking coil.

14. In an apparatus of the character de: scribed, the combination of a furnace, a cracking coil in the furnace, a digester of lar er cross sectional area than the cracking coiconnected therewith, a series of vaporizin chambers, pressure regulating discharge va ves for said chambers, crossovers between adjacent chambers pressure regulating discharge valves on the crossovers, tubing connecting the first of the chambers with the digester, a preure regulating discharge valve on the tubing between the first chamber and the digester, and means to pump hydrocarbons into the cracking coil.

15. In an apparatus of the character described, the combination of a furnace, a cracking coil in the .furnace a digester of larger cross sectional area than the cracking coil connected therewith, a va. orizing kchamber, a plurality of connected ractionating condensers in series relation with each other, pressure regulating discharge valves for the condensers, ressure regulating discharge valves on t e connections between adjacent condensers, tubin connecting the vapoizing chamber with t e digester, coolin means for the tubing, a preure regulating discharge valve on the tubin between the vaporizing chamber and the tu -cooling means, and means to pump'hydrocarbons into the cracking coil.

. 16. In an apparatus of the character described, the combination of a furnace,',a

cracking coil in2the furnace, a digester of larger cross sectional area than the cracking coi connected therewith, a series of fractionating stills, pressure regulating discharge valves for the stills, crossovers between adjacent stills, pressure regulating discharge valves on the crossovers, tubing connecting the first of the stills with the digester, cooling means for the tubinga pressure regulating discharge valve on the tubing between the first still and the tubecooling means, and. means to pump hydrocarbons into the cracking coil.

17. In an apparatus'of the character dcscribed, the combination of a furnace, a cracking coil in the furnace, a digester of larger cross sectional area'l than the cracking coil connected therewith, a series of va orizing chambers, pressure regulating disc arge valves for the chambers, crossovers between adjacent chambers, pressure regulating discharge valves on the crossovers, tubing connecting the first of the chambers with the digester, cooling means tor the tubing, a pressure regulating discharge valve on the tubing between the first chamber and the tubecooling means, and means to pump hydrocarbons into the cracking coil.

18. In an apparatus consisting of a furnace a continuous tubular heating coil, a dgester of larger cross sectional area than the cross sectional area of the tubular coil, a

top outlet connection for Vdischarging thev products from the digester and a bottom purging valve and connections connected to the digester, a pressure regulating and discharge valve, connections between the pressure regulating valve and the digester, and means for supplying hydrocarbons under pressure sufiicient to prevent vaporization throughout the system of heating coils, di-

ester and connections to the pressure reguating valve.

19. In an apparatus consisting of a furnace, a continuous tubular heatlng coil, a digester of larger cross sectional area than the cross sectional area of the tubular coil, connections between the digester and tubular coil, a top outlet connection for discharging the products from the digester and a bottom purging valve and connection connected to the digester, a pressure regulating and discharge valve; and a cooler in the connection between vthe digester and pressure re lating valve, and means for supfplying ydrocarbons to the heating coil and digester and under sufiicient pressure to maintain the hydrocarbons in a liquid condition throughout the heating coil,4 digester, cooler and to the point of tion through the pressure re ucing valve.

20. I-n the rocess of treating hydrocarbons, the com ination of steps conslstin in heati hydrocarbons in a continuous tu ular co1 to a temperature suiicient to crack them and under sucient pressure to subressure reducstantially prei-ent vaporization thereofthen redueing their rate of flow while maintaining then' pressure, and then successively stepping down the pressure on the liquid hydroearlmns to different predetermined degrees to permit the separate vaporization of hydroearbons of different boiling points.

21. ln the process of treating hydrocarbons. the combination of Steps consistinplr in heating hydrocarbons to a temperature sufiieient to eraek them, then reduelngqr their rate of flow while maintaining them under suHieient pressure to substantialivv prevent vaporizution thereofl then allowing them to raporize by successively stepping down the pressure on the liquid lrvdrorarlmns to dit'- ferent |n'edetermined degrees to permit the separate vaporization of lrvdroearbons of different boilintgr points` and separately condensing the vapors ol' different boiling points.

22. In the process of treating hydrocarbons, the combination of steps, consistingr in heating hydrocarbons in a single passage through a continuous tubular coil to a telnperature snfiirient to erack them, then redueingr their rate of flow while maintaining them under sulieient pressure to substantially prevent vaporization thereof then allowing them to vaporize, and then stepping down the pressure and the temperature of the vapors to different predetermined delfrees to permit the separate condensation of hydroearbons of different boiling mints.

23. ln the process of treating` hy( roearbons, the combination of steps consisting in heatingr hydrocarbons to a temperature sufficient to crack them and under suffieient pressure to substantially prevent vaporization thereof, reducingr the rate of flovv and the temperature while under cracking; pressure, and then steppnig down the pressure and step )ing up the temperature of the liquid hydioearbons to different predetermined degrees to permit the separate raporzation of hydrocarlmns of different boiling points.

Signed at Los Angeles, California, this 8th day of August, 1921.

JOHN C. BLACK.

Witnesses GEORGE H. HILES, L. BELLE VVEAvER.

DISOLAI MER.

1,431,772.Jofm 6'. Black, Destrehan, La. Process .um Armures ron Tm'rmo Hrnaooansoxs To Pachuca T1msn nr 1.0mm Bonnro Pom'rs. Patent dated October 10, 1922. Disclaimer filed August 9, 1928, by the assignee, Gasoline Products Umnpa'ny, I'rw. Hereby disclaims claims 1 and 3 of said atent, which read as follows: 1. In an apparatus of the character described the combination of a furnace, n cracking coil in the furnace, means connected with the cracking coil to maintain the hydrocarbons at cracking temperature` said means also decreasing the rate of flow V of the hydrocarbons after leavin the cracking coil, a ipc line connected therewith and havin a discharge end, a va ve located on the line tween the cracking coil and the said discharge end and means to produce suicent pressure on the hydrocarbonsV to P event vapor-ization thereof while-at crackin temperature.

3. In an apparatus of the character describe the combination of a furnace, a cracking coil in the furnace. a digestor of larger cross sectional area than the cracking-coil connected therewith, a fractionatng apparatus, a pressure regulating valve between the digestor and fractionating apparatus. and means for su lying hydrocarbons to the coil and digestor under pressure and maintaining a cient pressure in :ge sgsbem-againstthe regulating valve to prevent vaporization of the hydrocar ns.

[Oficial Gazette September 11, 1.928.]

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