US2022280A - Art of and apparatus for converting hydrocarbons - Google Patents

Description

Nov. 26, 1935. w. GOMORY 2,022,280

ART OF AND APPARATUS FOR CONVERTING HYDROCARBONS Filed Aug. 13, 1930 2 Sheets-Sheeu l ,nwa/fox Nov, 26, 1935. w. GOMORY 2,022,280

ART OF AND APPARATUS FOR CONVERTING HYDROCARBONS Filed Aug. 15, 1950 2 Sheets-Sheet 2 Patented No 26,1935

UNITED STATES:

ART or AND armnarus FOR convsu'rmo muocmmons I L. Gomory, Paris, France, assignor to Standard Oil Development Company, a corporation of Delaware Application August 13, 1930, Serial No. 475,101

In Great Britain July 15, 1930 8 Claims. (cl. res-4t) This invention relates to the conversion of hydrocarbons and more particularly to the treatmer t of petroleum oils-for the production or lowboiling products therefrom and the said invention has for its object to provide an improved and eflicient process and apparatus for obtaining in a continuous operation a maximum yield of low-boiling products with a small initial outlay and a small maintenance cost and with the minimum production of products of low market value.

I am aware of processes in which the oil is heated under pressure to a cracking temperature in a coil and then maintained therein for a very short period of time, for instance 50 to 100 secends, and is then expanded into a tank with 'or without simultaneous and instantaneous cooling to materially below the cracking temperature, for

1 instance, to 480 degrees 'F'.

In such processes, -on account of the very short reaction time given to the oil in the coil at the cracking temperature, the amount of decomposition that takes place is comparatively v small, therefore nocommercial yield of gasoline can be obtained without subjecting the original oil to a large number of retreatments which obviously materially increase the cost of working these processes.

Moreover owing to the sudden and mate'riai cooling of the streamof oil entering the tank a great amount of uncracked oil is removed with the residue, so that the gasoline which could be recovered therefrom is lost. Furthermore a great amount of heat is uselessly removed from the system.

My improved process at once eliminates.

these disadvantages and enables a maximum yield of gasoline to be obtained "with lowest cost and minimum formation of products of low market value.

According to my invention the oil to be treated is passed under high pressure through a heating and cracking done, for instance a continuousheated coil or series of coils, in which it is heated to cracking temperature'and subsequently maintained therein at such temperature for suiilcient time, for example, 2 minutes or more, to obtain maximum conversion of the oil without undue formation of carbon. The products are passed to a vaporizing zone, which is under reduced pressure, the temperature of the stream of oil enter-=- ingsaid zone lacing regulated without permitting and "the residue is withdrawn from the vaporizing 'zone. The residue removed from the vaporizing zone may advantageously be subjected to a de- 'structive hydrogenation treatment.

The desirable cracking temperature and pres sure and the reaction time will vary with the nature of the material to be treated. Temperatures of 750 to 1250 F., pressures of 150-3000 lbs. per square inch or more and-a reaction time of two minutes or more than two minutes are employed, depending on the nature oi the material.

The vaporizing. "tower or evaporator is operated at materially reduced pressure, preferably at atmospheric pressure; and the temperature of the stream of oil entering the vaporizer may be regulated by the introduction therein of cooler oil, for example reflux condensate obtained in the system, in such a manner that a constant -temperature is maintained at the bottom of the vaporizing zone or tower, this temperature being suiliciently low to ensurevthat no material cracking shall take place, at the same time the temperature is not permitted to fall below that which is necessary to ensure the vaporization of all the uncracked fractions which are adapted to be further cracked, and to prevent the formation of a large amount of residue. This temperature should lie between '580 degrees F. and 750 riegrees F.

The temperature at the-top or the vaporizing tower or evaporator is regulated in any convenient manner (for instance by passing the iced oil, or any other oil, through cooling coils located in the top of the evaporating tower or by spraying oil into the tower) so that only light cracked vapours are allowed to pass to iracticnators and condensers and so that all the other fractions which have vaporized will be condensed and recovered as reflux condensate. i0

Furthermore; the residue obtained 'in the evaporator may be introduced either wholly or partly into the inlet of the heating and cracking zone; or the said residue may be introduced at an intermediate point or points of the coil or series of coiis,.whioh forms the combined heating and cracking zone. The residue may also be introduced into the stream of oil at the outlet end of the coil. The residue may moreover be introduced into the system at two or more of the pool so tious above mentioned.

The reflux condensate from the vapcriaing zone is continuously returned without substantial loss of heat either wholly or partly into the inlet of the coil or series of coils; or the said reflux 5 condensate may be introduced at an intermediate point or points ofthe coil. or series of coils. Part [oi the reflux condensate may advantageously he introduced into the stream or oil at the outlet end of the coil or series of coils to regidate'the tom so i perature of such stream of oil as it enters the evaporator. The reflux condensate may 'however be introduced into the system at two or more of the positions above mentioned.

A further means of effecting the regulation of the temperature of the stream of oil entering the evaporator consists in that part of the oil from the coil or series of coils is taken from an intermediate point in such coil or series of coils and is introduced into the stream of oil passing from the coil or coils into the evaporator.

The quantity of reflux condensate introduced into the stream of heated oil or cracked products passing from the heating and cracking coilor, coils to the evaporator is so regulated that it will control the temperature of the oil before the same enters into such evaporator, or will control the temperature of the oil in the evapoator. Furthermore part of the oil passing through the coil or coils may be taken from an intermediate point of the coil or coils and introduced into the stream of heated oil passing to the evaporator, in order to regulate the temperature thereof.

The reflux condensate before it is introduced into the coil or coils, or into the outlet of the coil or coils as above mentioned, is advantageousinto the fractionator or fractionators.

vapours obtained from the residue in the second..= vaporizing zone may be separately fractionated or they may be partly introduced into the first 0 be partly introduced into the vaporizing zone,

e. g. the ,heavier fractions, and partly into the fractionator or fractionators, ve. .g. the lighter fractions. Or the said light vapours may be fractionated in a separate fractionaton.

In order to oonvert the residue, which is continuously withdrawn from the evaporator, into more valuable products, such cracked residue is advantageously subjected to destructive hydrogenatiomsuch as shown in my co-pending appl ication Ser. No'. 475,099, filed August 13, 1930.

The residue removed from the vaporizing zone may, if desired be'subjected to'a second vaporization at atmospheric or super-atmospheric pressure, so that the amount of residue is materially reduced and additional valuable light hydrocarbons are obtained therefrom, the vapours so obtained being preferably introduced into the first vaporizing zone, the final residue being withdrawn and if desired subjected to destructive hydrogenation in any suitable manne for example, as described in my copending application Ser. No. 475,099, filed August 13, 1930;

The vapours obtained from the residue in the second vaporizing zone may be introduced vaporizing zone and partly into the fractionator or fractionators receiving the vapours from the:, evaporator, e. g. the heavier and lighter fractions respectively.

In some cases it may be desirable to subject residue from the first vaporizing 'zone to a second vaporization at atmospheric or super-atmospheric pressure in such a manner as to vaporize all volatile matter contained in the residue,-;so that, besides a small amount of coke, a great fullyzrdevelopednform f,"

The

amount of more valuable light productsis obtained. The resulting solid residue is removed and the vapours are preferably introduced into the first vaporizing zone or evaporator or if desired they may be introduced into the frac- 5 tionators or into both the first vaporizing zone and the fractionators. The vapours obtained from the residue in the second vaporizing zone are advantageously subjected to fractional condensation, the uncondensed vapours being passed 1 into the first vaporizing zone or into the fractionators, or into both the first vaporizing zone and the fractionators, and the condensed heavier fractions being returned to the systemwith or without subjecting them to distillafiiimuni 3.25mi, '15 which may be the still in which firearms-gonad densate from the first evaporating mneiisgresnmnr In all the above forms of my impimpdmrqcfifiibo the vapours may be separated into ggoclmidmointii gasoline and other valuable fractiqnsrimmmssfiao ing them through fractionators and pectifieigazl provided with controlled coogngggyllgiohodoaimgio maybe effected either by thegiafid oitmaby mange! independent there-of.

jecting the uncondensed urnouts a lrlt ygasga to diss ciat and n uot omarthe zsiasaooiatedsi v v p nd gases to sdesttuottva hxd oeenam ti n p a s t t yimainbeliusad rim-1th; ddtirle 51-30 The presents:inventiomsalsos oompnseszsuitable apparatus for carrying into practice the sever-Tal a forms ofamyzimproved process: 1 50 In ordenthatwthesirivention,ma gbefullynnderw stood reference-willtbe made'to the accompan ing drawings in whiclm,

Figure 1 shows in diagrammatic form an, rangernent! of :1 the heating-andz-crackingwzone 55 andrevaporatorfi accordance' with the present inventionuand i- :w:

EEigur'e ,2 2 showa IIlYxxiDVGDtiOD.

,lReferringe-totl 'igu ,l forced: bypmeans 10f -ai pump; Arthrough'v line B intorscooling coil C; wwhi'ch i swtarranged ,u'nthe v upper: part of a the l evaporator D, and, 'zthencee through Jline: E into thel inlet'endiof ::the section; 65 G:,-of a. heating and cracking c-oil: whichicome l prises threepipe sections, (3, IL? 1d 'J..= :The oil passes first; through section; (3; thenqthrough. section-H and finallynthroughnsection G. Cracked oil is discharged: from: vthe, coil through valved 70 line K into theevaporatorwhich preferably has baflle platesl), suitably disposedtherein to ensure. a thorough contact between ascending vapour, and descending liquid. Steam may be injected into the evaporator D through spray pipe T. 75

nationhood; rgmminim m A novel feature of my invention comprises M3 5 Uncondensed vapours are withdrawn from the evaporator D through a. valved line L to fractionators a'nd condensers, (not shown) whilst the unvolatilized residue formed in the evaporator is withdrawn therefrom through valved line M and passed to a destructive hydrogenation plant or otherwise suitably disposed of. The reflux condensate produced in the evaporator is collected in a pan N from which it is withdrawn and forced by means of pump through line P to the inlet of the section G of the coil F. Part of the reflux condensate may be passed to an intermediate point, of the coil for example the inlet of section J through branch line Q or to the outlet end of said section through branch line R. Part of the oil passing through the coil F may be withdrawn from an' intermediate point thereof such as the outlet of section G through line U and introduced into the stream of oil passing from the outlet of the coil to the evaporator D. Cool feed oil may be introduced into the evaporator D through branch line S.

Referring to Figure 2, the oil to be treated is drawn from any convenient source of supply I by means of a pump 2 and is forced through line 3 into a heating coil 4 located in a furnace setting 5, the oil then passing through line 6 into an evaporator I. Valved by-pass lines 99, 9| and 92 are provided in line 3 whereby a regulated amount of feed oil may be sent through cooling coils 8 and 9 located in the upper parts of the fractionators l9 and II respectively, and thence through line l2 into line 6. A by-pass line I3 is also provided in line 3 whereby all or part of the feed oil may be passed directly to the evaporator 1 without passing through heating coil 4. A heating coil I4 is provided in the lower portion of evaporator 1. Moreover steam may be inject ed into the evaporator through spray pipe. I5. A

cooling coil I6 is provided in the upper portion of the evaporator I through which feed oil passing from line 6 to heating and cracking coils 23 may be passed whilst a further cooling coil I1 is provided in the evaporator, so that the cooling may be controlled by means which are independent of the supply of feed oil. Bafiie plates H are suitably disposed within the evaporator I to ensure a thorough intermingling of ascending vapour with descending liquid and the evaporator is advantageously heat insulated. Reflux eondensate formed in the evaporator I is collected in a pan l8 from which it is withdrawn through line 19 by means of a pump 29. Reflux condensate is forced by reflux pump 2| through line 22 into the inlet of the heating and cracking coil 23 which is located in a suitable furnace setting 24. The heating and cracking coil 23 comprises three pipe sections 25, 26 and 21 which are situated in different positions in the furnace and feed oil from cooling coil I6 is passed to the inlet of the heating and cracking coils 23 through line 28. The heating and cracking coils may advantageously be built up of a series of straight pipes in accordance with standard practice, e. g., with the ends of the pipes extending through the flue walls and suitably connected by headers Reflux condensate from the evaporator I may also be passed by means of pump 36 through line 31 to the inlet of the coils 23 and the reflux condensate may be passed to intermediate points of the coils through lines 38 and 39 or to the outlet end of the coils through branch lines 49 and 4|. Heated oil may be withdrawn from an intermediate point of the coils 23 through line 42 and introduced into the stream of cracked oil passing from the outlet end of thecoil through line 29' into the evaporator 1.

Residue is withdrawn from the bottom of the evaporator I through line 43 and may be withdrawn from the system by line 44 or passedlo through line 45 to the inlet of the heating and cracking coils 23 by means of residue pump 46. Said residue may be passed to an intermediate point of the heating and cracking coils 23 through, branch pipe 41 or to the outlet of the heating and cracking coils through branch pipes 48 and 40.

Vapour from the evaporator I passed through line 54, having a pressurecontrol valve 55, into the lower portion of fractionator II from the upper portion of which vapour is withdrawn by line 56 to a second fractionator l0. Cooling coils 58 and 59 are provided in the upper portions of the fractionators; i9 and II respectively to provide cooling means independent of the supply of feed oil, whilst spray pipes 60 are provided in the lower portion of the fractionators for the injection of steam. The fractionators ill, II are preferably heat-insulated. Condensate from the fractionators l0 and II is withdrawn through coolers 6i and 62 to storage whilst vapour from fractionator I0 is withdrawn through line 63 to a condenser 64 from which condensate is passed to tank 93. Incondensable gas is separated from condensate in tank 93 .and is withdrawn through line 51 by pump 51. Preferably the incondensable gas is used as a make-up gas in a destructive hydrogenation plant.

-Il'hevapours and gases not condensed may be subjected to dissociation and the dissociated vapours and gases are conducted to a destructive hydrogenation plant so that they may be used in 1 the destructive hydrogenation of hydrocarbons, as shown in my co-pending application Ser. No. 475,102, filed August 13, 1930.

Part or all of the condensate from the fractionators l0 and II may be passed by pump 80 to the evaporator I through line 19.

When it is desired to subjectthe reflux condensate from evaporator I to distillation prior to its return to the coils 23, the reflux condensate is passed through line 65 into the re-run still 66 into which steam can be passed through line 65 and which still can be' heated directly or otherwise.

Residue from the re-run still 66 may be withdrawn from the system through line 68 orretumed to the coils through line 68' and line 31.

of the vapour may be passed through branch pipe 10 to the evaporator I.

In cases where it is desired to subject the residue from the evaporator I to a second vaporization, such residue is withdrawn from the evaporator by pump '|2 through lines-H, 12 and branch line 13, into auxiliary evaporators 14 and"'|5, which can be. heated by the injection of steamthrough spray pipes 16 orby direct heat or both. Final residue from the auxiliary evaporators is withdrawn by pump 94 through line 11, and is passed to a hydrogenation plant or is otherwise suitably disposed of. Vapour from the auxiliary evaporators 14, I5 is withdrawn through line 18 and is passed either to evaporator I through line 8| or into fractionator ll through 7 branch lines 82, 83. Or if desired, such vapour may be passed through line 84 to a fractional condenser 85 from which uncondensed vapours are returned through line 86 either to the evaporator 1 or to the fractionator H. The fractional condenser 85 is heat insulated and. is provided with a cooling coil 85' in the upper portion thereof, and with a spray pipe 85" for direct steam in the bottom thereof. The condensed heavier fractions from the fractionator 85 are passed by pump 81 either to the re-run still 56 through line 88 or to the coils 23 through lines 89, 68 and 31.,

Valves are suitably disposed throughout the apparatus to control the flow of oil to the diflerent parts of the system and to enable any desired pressure to be maintained therein. All the lines conveying oil into the heating and cracking coil or to the outlet thereof, are provided with check valves to prevent the hot products from backing into these lines, whilst all the lines conveying hot oil are heat-insulated.

, I claim:

1. A method of converting hydrocarbon oils which comprises heating the oil to a cracking temperature in a heating coil, transferring the hot products from the heating coil to a vaporizing zone, collecting a reflux condensate in'said vaporizing zone, subjecting the reflux condensate to distillation in a' separate reflux stripping zone, passing an unvaporized liquid fraction from thestripping zone to said heating zone, subjecting the rmcondensed vapors from the vaporizing zone to fractionation in a separate fractionating zone, conducting the vapor fraction evolved in the reflux stripping zone partly to the vaporizing zone and partly to the fractionating zone, and removing and condensing vapors from the fractionating zone. v

2. A method substantially as described in claim 1, in which a portion of the oil undergoing heating in the heating coil is withdrawn from an intermediate point of the coil and injected into the hot products being transferred from the heating coil to the vaporizing zone.

3. A method substantially as described in claim 1 and in addition thereto.-.the steps of subjecting residual liquid from the vaporizing zone to distillation in a distillation zone and returning the vapor fraction evolved in said distillation zone.

to the vaporizing zone.

4. In an apparatus for the conversion of hydrocarbon oil, the combination of an heating coil, a vaporizer, a transfer line connecting the heating coil and the vaporizer, a partial condensing means, means for recovering reflux condensate in said vaporizer, a separate reflux condensate stripper, means for conducting reflux condensate from the vaporizer to the stripper, a separate fractionating means for recovering a condensate from the 'uncondensed vapors from the vaporizer, means for conducting said vapors from the va porizer to the said fractionating means, a vapor 'line for conducting vapors from the stripper. to

the vaporizerand to the fractionating means,.

and means for bottom from the stripper to the heating coil;

5. An apparatus as describedin L drocarbon oils the combination of a heatingcoil,

a vaporizer. a transfer line connecting the heating coil and the vaporizing zone, a fractionating column adapted to receive'vapors from the vaporizer, a reflux stripper, a still, means for conducting reflux from the vaporizer. to the stripper and for conducting residue from the vaporizer to the still, a second fractionating column adapted to receive vapors from the still, means for conducting reflux condensate from said second frac- .tionating column to said reflux stripper, and means for removing and condensing vapors from the first and second fractionating zones and the a stripper. 1

7. Apparatus of the character described comprising a heating and converting means adapted for heating and maintaining oil at cracking tem-- l5 perature and under pressure and means for supplying oil under pressure to the inlet of the heating and converting means, vaporizing means into which the products fromsaid heating and converting means are discharged under reduced pressure, the said vaporizing means being provided with means for recovering and separately withdrawing vapors, reflux condensate and residue and being also provided with cooling means in the top and heating means in the bottom thereof, means for delivering the charging oil through the above mentioned cooling means located in said vaporizing means to said heating and converting means, means for supplying reflux condensate obtained in said vaporizing means to theinlet and outlet of said heating and converting means and to intermediate points thereof, means for discharging oil from an intermediate point of said heating and converting means into the stream of products passing from said heatv ing and converting means to said vaporizing means, separate distilling means connected to said vaporizing means to separately receive reflux condensate and residue from said vaporizing means, and means for removing and condensing vapors formed in the vaporizer and the distilling means.

8. Apparatus of the character described comprising a heating and converting means adapted for heating and maintaining oil at cracking temperature and underpressure and means for supplying oil under pressure to the inlet of the heating and-converting means, vaporizing means into which the products from said heating and converting means are discharged under reduced pressure, the said vaporizing means .being provided with means for recovering and-separately, withdrawing vapors, reflux condensate and residue and being also provided with cooling means in the top and heating means in the bottom thereof, means for delivering the charging oil through the above mentioned cooling means located in said vaporizing means to said heating and converting means, meansjfor passing charging oil directly into said vaporizing means, means for 60.

supplying reflux condensate obtained in said vaporizing means to the inlet and outlet of said heating and converting means and to intermediate points thereof, means for discharging oil from an intermediate point of said. heating and converting means into the stream of products passing from said heating and converting means to said vaporizing means, separate distillingmeans connected to said vaporizing means to separately receive reflux condensate and residue from said vaporizing means, and means for removing and condensing vapors formed in the vaporizer and distilling means.

- WILLIAM L. GOMORY.

Images