US1840012A - Apparatus for making gasoline - Google Patents

Description

.kamD 5; 1932. o. BEI-MER APPARATUS FOR MAKING GASOLINE Original Filed Nov. 21. 1918 Patented Jan. 5, 1932 g l UNITED STATES' PATENT ori-lcs OTT() BEHIMER, 0F PQRT ARTHUR, TEXAS, ASSIGNOR, BY MESNE ASSIGNMENTS,'TO THE TEXAS COMPANY, QF NEW YRK, N. Y., A CORPORATON lOli DELAWARE vAll?IPARAJS FO MAKING GASOLINE Original application lecl November 21, 1918, Serial No. 263,562. `Divided and this application led January 3 0, 1923, Serial No. 615,850, and in Canada December 3, 1921. 4

This invention relatesto ap aratus fdr out necessarily being subjected to' additional converting or crackin high boi ing hydroheat, it undergoes a molecular decomposition carbon oils into loweroiling products, such whereby carbon and light products are I as gasoline or other condensable light oils,l formed and liberated. It will be understood 5 and more particularly to apparatus adapted that oil cracking or conversion is dependent i. 50

. for carrying out the process disclosed and not only upon the relative conditions of presclaimed in my copending application Ser. No. sure and temperature but also upon the time 263,562, led Nov. 21, 1918, of which the clement with respect thereto, that is,-the \presentapplicationis a division. necessary pressure and temperature must be im' in prior apparatusl for cracking hydrocar lmaintained for a suiicient period of time55 -fbo'n oils', considerable dilliculty has een exto enable the molecular decomposition or conper'ienced on account of carbon formations, version to take place. According to the pres- 'whichoccur o'n the sides of tubes. and stills ent invention, this time factor is :so conexposed to the heat required to carry on the trolled, by regulating the rate of heating the #o crackingv operation. oil passing through the heating zone that the 60 It is a broad novel feature of the herein' temperature thereof is progressively raised in disclosed `aparatus, that substantially all of transit and reaches the desired cracking tem- -the crackivng operation occurs in a vessel to perature near the'end of the heating coil at which no vexternal heat is applied, except at, about the time or a Alittle before `the oil ig20 such times and in such quantities as are neccs emerges therefrom. Thus, although the oil 65' vsary to compensate for heat losses, the oil is subjected to cracking heats in the heating prior" toits introduction to such vessel havzone, this temperature is attained only just ing been subjected to a high degree of crack-4 previous to the exit of the oil therefrom, and ingheat and the excess heat of the 'oil itself therefore, the oil leaves the heating coil bebeine' used to eii'ect its' owny decompositionf fore any substantial decomposition and in- 70 aticonsequence, I avoid substantial carbon cidentdeposition of carbon takes place. Subformations ofthe destructive character sequently, the highly heated oil in a state :which have proved such an impediment to of incipient decomposition is delivered to prior systems. The removal of the vcracking the cracking zone, where the desired tempera- "230 operation from the heating zone also reduces ture and pressure conditions are continuously 7.5

-tfhe danger frm fires f such as frequently sustained and the cracking of the oil and the occur where cracking is carried on` in highly incident deposition of carbon are effected. heated stills and coils exposed to direct heat. The bulk of the carbon is removed from thev More specifically my apparatus preferably circuit by withdrawing from the cracking 35 embodies a novel cyclic system in which a \zone, portions of the residualoil.` Although so circuit of oil is constantlymaintained under the process, in its broad conception, is comvarying liquidgand vapor phases. TheV oil plete at this stage of the operation, the light tobeftreated on entering this circuit is subproducts preferably continue the cycle, leav- Y- fjected to ahigh degree of heat, but the time fing theoracking zone in the form of vapor T40 element isso controlled with respect thereto and gas. IThese vapors and gases are then S85 that there is comparatively little'decomposisubjected to a reduction in temperature, tion and deposition of carbon while it is ex whereby the heavier constituents thereof, posed to this external heat, the oil being Such as kerosene, are condensed. ThecOnrapidly removed from'ythe heating zone and densate is preferably combined with the '45. conducted to the crackingA zone, where with-A charging oil enteringthe heating zonethus R9,`

completing the cycle. rlhe constituents of the desired volatility are removed from the circuit and condensed. The outlets from the circuit are so controlled that the entire system 5 is maintained under a pressure suiiicient to insure the desired molecular transformation. My apparatus is to be distinguished from those of the prior art, in which a circuit of liquid residuum is kept in circulation. Vhen such oil is kept in circulation, considerable. quantities of carbon are formed, owing to the readiness with which this type of oil carbonizes when exposed to high temperatures, the carbon forming in fine particles in the o il, and Wherever it comes in Contact with heated metal surfaces, it attaches itself thereto and builds up deposits, which often cause the choking of tubes and coils. It also crystallizes the metal surfaces, therebyv decreasing the tensile strength of the metal and causing the bulging and breaking of such surfaces. Any residual oil resulting from the cracking operation will necessarily contain a considerable amount of heavy polymerization productsand carbon held in suspension in the oil, and to circulate such a residue through heated tubes is to continually pass-into or produce in such Atubes a large amount of free carbon. In my system, `I do not circulate a residuum, but instead keep the residual oil removed from the application of external heat and Withdraw the heavier portions thereof, Which contain the bulk of the carbon, from the cycle at the cracking zone, and vcontinue the cycle by means of the vapor generated, which contains the condensable product' desired and also certain heavier vaporous con- Y stituents which are used to complete the cycle. By removing the heavier residuum from thecycle, I keep the circuit free from this source'of carbon formation, and since I conduct substantially all of the cracking in a Avessel to which either no external heat is applied or only a small quantity of heat is applied to maintain the re uisite tem erature conditions, I am thus ab e to effectively remove the carbon formed. Incracking oil for gasoline, there is enerally formed a considerable quantity o vapors heavier than gasoline, which may be generally designated by the term, kerosene. I preferably employ these heavier vapors as a carrier for the lighter vapors; they assist in maintaining a current of vapor by which the gasoline is removed from the cracking zone to a separator Where the kerosene vapors are condensed and removed from the gasoline vapors which pass on to the condenser. The kerosene condensate, preferably at a temperature, not materially below its boiling point, is injected or otherwise suitably forced into the heavy oil charge entering and flowing through the heating tubes Where? by a foamy agitated mixture is produced by u the acceleration of the circulation in the heat'- ing tubes resulting from the increased volume of oil therein, thereby preventing the settling and flow of the heavier portions of the oil along the bottom of the highly heated tubes and the consequent local overheating and carbonization of the oil, thus keeping the tubes substantially free from any slight carbon formations. The kerosene constituents are an excellent mechanical conductor of heat, and there is thus produced a heat cycle which materially assists in maintaining the proper temperatures in the heating) and cracking zones. By maintaining these odies in constant circulation, the kerosene constituents, which Aunder existing methods have been found so difficult to decompose into lighter products, are, in my system, ultimately reduced to gasoline.

I have devised certain novel apparatus Which is adapted. for carryingout my process, and illustrate the preferred form thereof in the drawings in which -Fig. l is a diagrammatic elevation of said apparatus,

Fig. 2 is a detail view of a modified cracking drum which'may be substituted for that of Fig. 1. It will be understood that, other apparatus besides that illustrated may be used in carrying out my process.

Referringto Figlof the illustrative drawings, a tubular heating coil is located in a furnace 2, having a burner 3 and a stack. As shown for illustrative purposes, the coil l comprises a plurality of horizontally disposedy rows of tubes extending through the furnace and placed the one above the other. The vadjacent ends of ea'ch alternate pair of tubes in each horizontal row are conveniently connected together by horizontally positioned return bends or ittin s to form horizontal coils. The several iorizontal coils thus arranged are conveniently connected togetherat their right-hand ends by vertically disposed return bends or fittings, as shown in Fig. 1, to form a single elongated and continuous heating coil through which the oil flows and is heated to the required degree. This coil is of extended length and restricted cross-section and has a relatively large and effective heatin surface Wherebythe stream of oil passing tv erethrough is enabled to eficiently absorb heat and reach a high temperature with rapidity. A checkered brick baffle 5 having openings 6 may serve to distribute the heat evenly over the coil. A fresh oil charging line 7 having a jet or injector .7, extends to a pump 8, which is connected to a suitable source of oil supply (not shown). The pipe 9, having a valve 10, extends from the heating coil 1 to an'enlarged cracking drum or chamber 1l, Within Whichpit may terminate in a distributor 9*". This distributor A9"- may be of any suitable form to thoroughly distribute and diffuse the charging oil throughout the body of oil tact'of'the hi hly heated.' charging .oil with l' fil 1,840,012

in. :the drum` whereby f'an-'itiniate' econ'- -protect it lagainst heat radiation and is equipped with a valved draw-off 12,'a vapor outlet 13, and an oil gauge 14. The vapor outlet 13 extends to a separator 15,' hav-v ing. a vapor outlet 16, and a condensate outlet 17. The vapor line 16 terminates in a water'- cooled condenser coil 18, having an outlet 19 equipped with a Aregrulatable pressure valve 20. If desired` the valve 20 may be placed in the vapor line 16, but I prefer to maintain the pressure -in the heating coll, cracking I drum and separator through the condenser.

Y The outlet 19 terminates in a collecting tank 21, having a valved gas outlet 22 and a valved distillate outlet 23. The condensate line 17, Which is preferably insulated as. indicated at 17b is equipped with a valve 17a and is connected to the charging line 7 at the jet 7*.

In lconducting they process with the apparatus illustrated the oil to be treated is forced through the charging line 7 vunder-- considerable pressure, and is rapidlyl fiowed through the heating coil 1, Where it is -heated to the desired crackingv temperature. Preferably this temperature is somewhat higher than the temperature at which it is desi-red to conduct the cracking opi eration and may or may not result in subi enters the drum which is 'of ample volume.-v

stantial vaporization. The oil on being forced through the coil acquires a high cracking temperature but on accountl of the rapidity of its How,- decomposition is only in the incipient stages when the oil is discharged through the 'pipe 9 into the heat insulated cracking drum 11 Where a constant body of oil is maintained at a cracking .temperature under pressure. The distributor 9, if employed, serves to discharge the oil into the cracking drum in a Wide stream,\thus thoroughly mixing thehot oil with the li uid body of oil maintained in the drum and di using the heat therethrough. This heat diffusionv is materially aided by using a 'distributor with serrated edges. The rapid flow of the oil through the coilwhere it is closely confined is here suddenly retarded, as the oil Thus the excess heat of the oil operates to maintain the'body of oil at the desired cracking temperature and molecular decomposition and distillation are carried4 on vigorous# ly, the higher boiling hydrocarbons continually breaking up into hydrocarbons of lower boiling point. The vapors and gas generated gather in the upper part of the cracking drum and pass out through the vapor outlet 13 to the separator 15,.where there is effected a separation of hydrocarbonsof desired volatility from those of less volatility. The hydrocarbons of the desired volatility pass out .through the vapo'rv line 16, bye'which they are conducted tothe condenser 18, where they areA condensedgifand the condensed distillate iseither intermittently or preferably continble 'device for forcing the condensate into the charging stream. The separator is preferably somewhat elevated so as to give a considerable head of liquid in the pipe 17, which preferably contains a U bend,'as illustrated, m order to form a liquid seal therein. yThis head of liquid, together with the high pressure at which the oil in thecharging line passes the ]et, this pressure being ordinarily from 50 to 100 pounds higher than the pressure in the drum, 4insures that the condensate shall be constantly and positively drawn into the c harglng line and forced into the coil 1. The lntroduction of this hot condensate into the charging line increasesthe volume of oil 1n the heating, coil thereby acceleratinc the flow therein and producing a foamy mixture sc that local overheating is prevented and the coil 1s kept Substantially free from any slight carbon formations. This condensate consists 1n a type of hydrocarbons which when decomposed doesv not yield any great amount of carbon so that the oil charge is constantly being diluted with oil capable of being decomposed into lighter products Without the productionof large amounts ofcarbon. Thiscondensate reaches the jet in a heated condition, preferably at a temperature not materially belowy its boiling point, so as to heat .the charge of oil entering the heating coil. The heat cycle formed by the kerosene constituents contributes to the maintenance of' the proper temperatures in the heating coil and the cracking drum. By injecting or otherwise suitably forcing this condensate into the heating coil I increasevthe volume of oil flowing therein Without increasing the.

the nature of gasoline a temperature in the drum 11 of from 700 F. to"850 F. with a teniperature' in the'coil 1 of 700 F. to 950 F. is ordinarily used.V For example, in cracking a paraffin base gas oil of-aBaum gravity of about 34, a temperature of 850 F. in the coil and of 77 5 F. inthe drum with a ressure of approximately 200 pounds has en used to advantage. i

The oil to be decomposed is constantly forced into the heating coil thereby causing a steady stream of heated oil to enter the cracking chamber. The residuum is withdrawn preferably at such a rate that there is maintaineda constant body of oil in the cracklng zone.

1t is desirable to-equip the apparatus with the valves and 17n lso that 1n case there is a break in the heating coil the effect' of any fire resulting may be localized by closing said valves, whereby the bulk of t e o1l in the system will be retained in the cracking drum 1-1. It is understood that in the normal operation of the process these valves are open. i

Auxiliary heat may be supplied to the cracking drum in any suitable manner if desired and a convenient method of providing this auxiliary heat is, as shown in Fig. 2, to insulate only the upper part ot' the drum and apply heat at a moderate temperature o r 1n a relatively small quantity from any suitable heater such as is designated.' In the early stages ot' a run, since there is no danger of overheating a carbon-free surface, the drum may be heated freely until the necessary heat cycle has been generated and decomposition has begun. For this reason the arrangement of Fig. 2 possesses certain advantages over thatof Fig. 1. But when decomposition begins, with a consequent deposition of carbon, the heat must be reduced as otherwise the v carbon would accumulate on the hot surfaces and build up tenacious formations thereon, thus preventing the effectual removal of the carbon and asphaltic bodies. As the run continues only a moderate heat is applied, sufficient only to oll'set the loss of heat due to radiation and distillation. 'If desired the drum may be heated by means of waste heat from the furnace 2 or in any other suitable manner. f

The product. obtained by the `herein disclosed apparatus is, for a cracked product,

remarkably sweet, in other words, low in unsaturated compounds.

It is understood that I .use the terms gasoline and kerosene in thisapplication by Way of example and that these terms are taken as types of other similar distilates which may be produced by our process. I use the term gasoline asanexample of the Volatile prode uct desired which -under the temperatures and pressures used is a vapor in the `separator 15 and is condensable in the cooling coil 18. I use the term kerosene as an example of those constituents which under the temperatures and pressures used is a vapor in the vapor line 13 but is condensable in the separator 15. It is to be noted that the gravity and boiling point of the products which will condense in the separator 15 depends upon the temperature therein under the pressure Although for illustrative purposes the invention has been shown and described in connection with apparatus of more or less specific details of construction, arrangement and location of parts, and as embodying in its mode of operation a certain series and of oil un er pressure, an elongated heating4 coil connected at oney end to receive the stream of oil from the pump and adapted to heat the oil in transit to a cracking temperature, an enlarged chamber under pressure connected to the other end of said heatin coil and adapted to contain a body of liqui oil under distillation, means for discharging residual oil from said chamber and preventing the return of any residual oil to the system, a preliminary condenser in communication with said chamber for receiving the vapors therefrom and effecting a separation of the heavierconstituents by partial oo ndensation, and an open connection under pressure of the system including pu-mpinv means connected between the condenser an a. point under feed pump pressure on t-he inlet side of said heating coil for forcibly recycling the clean condensate free of residual oil and under pressure to said heating coil for retreatment.

2. Oil converting apparatus comprising a feed pump for continuously forcing a stream of oil under pressure, an elongated heating coil connected at one end to receive the stream of oil from the pump and adapted to heat the oil in transit to a cracking temperature, an enlarged chamber under pressure connected to the other end of said-heating coil and adapted to contain a body of liquid oil under distillation, means for discharging residual oil from said chamber and preventing the return of any residual oil to the system, an elevated preliminary condenser in communication with said chamber for receiving the vapors therefrom and effecting a separation of the heavier constituents by partial condensation, an open connection under pressure of the system between the elevated condenser and the charging line at a point between the feed pump and the heating coil in which condensate accumulates under a considerable head pressure and pumping means included in said .connection and operating in conjunction with the head pressure of the accumulated liquid therein for forciby recycling the clean condensate free of resi u ual oil and under for retreatment. v

In witness whereof I have hereunto set my hanfl this 25th day of January, 1923.

' OTTO BEHIMER.

pressure to the heating coil

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