US1810048A - Art of cracking hydrocarbons - Google Patents

Description

June 16, 1931.

E. C. HERTHEL ART OF CRACKING HYDROCARBONS Filed March 7. 1929 ATTORN EYS apparatus of special value in carrying outiii 11 I ic EUGENE C. HERTHEL, OF CHICAGO, ILLINOIS, ASSIGNOR T0 SINCLAIR REFINING COM- IEANY, OF NEW YORK, N. Y., A CORPORATION OF MAINE ART OF CRACKING HYDROCARIBONS Application filed March 7, 1929.

This invention relates to improvements in the combined vapor phase cracking of oils, such as gas oil orkerosene stocks, for, the production of lower boilingoils, such as gasoline, and the coking of heavy oils, such as crudes, topped crudes, flux oils, other residual oils and the like. The combined operation of the invention is of special application in the handling of crude stocks or residual stocks the handling of which usually involves diiiiculties due to corrosion or the products of which are usually refractory with respect to the usual refining operations, because of the character or quantity of sulphur com pounds in the stock, for example; but, as Will appear, the invention is, in certain aspects, of more general application.

The invention is of special applicationin conjunction with the combined vapor phase cracking and coking operations claimed in application Serial No. 340,996 filed February 18 1929, by Harry L. Pelzer.

The invention also includes an improved the invention.

In carrying out coking operations in which the stock to be reduced to coke is coked by direct heat exchange with the hot vapor mix ture discharged from a vapor phase cracking operation, as in the operations described in application Serial No. 340,996, mentioned above, for example, the stock supplied to the coking operation proper is advantageously supplied to the coking operation as a stock which has been reduced to a gravity approximating 15 degrees A. P. I. or heavier. In carrying out vapor phase cracking operations forthe production of gasoline in which the stock supplied to the vapor phase cracking operations is heated to temperatures of 9501150 F., for example, the stock supplied to the vapor phase cracking operation proper is advantageously supplied to the vapor phase cracking operation as a stock having a carbon residue content as determined by the United Gas Improvement Company gas oil distillation test not exceeding about 0.3%. This gas oil distillation test is well known to the art as, and is hereinafter referred to as, the U. G. I. gas oil distillation test.

Serial N0. 345,139.

According to the present invention, an oil determined by the U. G. I. gas oil distilla stock having a carbon residue content as tion test not exceeding about 0.3% is subjected to a vapor phase cracking operation, the hot va or mixture I from the vapor phase crac ing operation is supplied to a coking operation in which a liquid oil mixture is coked by direct heat exchange with this hot Vapor mixture, the hot vapor mixture from the coking operation is discharged into and beneath the surface of a liquid body of oil maintained in the lower end of a bafiled tower, the raw oil stock to be reduced to coke is introduced into the lower end of the b'afiied tower to mingle with this liquid body of oil and the resulting oil mix-' ture is su plied from this liquid body of oil to the co ing operation, the vapors escaping from the upper end of the bafiled tower are subjected to a fractionating operation, the vapors escaping from the fractionating operation are condensed to form a distillate product, condensate separated from the vapors\ in the fractionating operation is supplied to the vapor phase'cracking operation, and a refluxing medium is supplied to the upper end of the bafied tower at a rate regulated to maintain the gravity of the oil mixture supplied from the liquid body of oil in the lower end of the baflied tower to the coking operation within the desired gravity range, say, 51-15 A. P. I. By supplying the raw 011 stock to be reduced to coke directly to the liquid body of oil inthe lower end of the baflied tower, the formation of coke in this tower is inhibited and, in conjunction with the supply of a refluxing medium to the upper end of the baflled tower, the carrying over into the fractionating operation of components increasing the U. G. I. coke contentof condensates separated from the vapors in the fractionating operation is minimized. By supplying the raw oil stock to be reduced to coke to the liquid body of oil in the lowerponents are separated from the raw stock to e reduced to coke, is made substantially in dependent of the rate at which this raw oil stock to be reduced to coke is supplied, making it possible to regulate this latter rate'primarily with reference to the coking operation proper. Condensate separated from the vapors in the fractionating operationmay, with advantage, be introduced into the upper end of the bafiled' tower as a refluxing medium; or the raw oil stock to be reduced to coke may, with advantage, be passed in indirect heat exchanging relation with the vapors escaping from the upper end of the bafiled tower before this stock is introduced into the lower end of the baflied tower and the condensate so produced su plied to the baflled tower as a refluxing me ium; or both of these refluxing media may be supplied to the bafiied tower and the rates at which they are supplied conjointly regulated.

The invention will be further described in,

the accompanying drawings connection with which illustrate, diagrammatically and conventionally, one form of apparatus, in elevation and partly in section with parts broken away, adapted for carrying out the invention, but it is intended and W111 be understood that the invention can be carried out in other and different forms of apparatus and that this further description is intended as exemplification of the invention. The accompanying drawings also illustrate a tower which, in combination with theyapor phase cracking apparatus and the coking apparatus illustrated, embodies another aspect of the invention.

In carrying out the invention in the apparatus illustrated, an oil stock having a carbon residue content as determined by the U. G. I. gas oil distillation test not exceeding about 0.3% is supplied through connection 1 to the vapor phase cracking heater 2, this stock is subyected q a vapor phase cracking operation in the apor phase cracking heater 2, the hot vapor mixture from the vapor phase cracking operation, without substantial cooling, is introduced into the 'coking receptacle 3 in which it is passed in intimate contact with a liquid oil mixture to be coked supplied from a liquid oil body maintained in the lower end of the baflied tower 4 through connection 5 by means of hot oil pump 6 and this oil mixture is thereby coked in the coking receptacle 3, the hot vapor mixture from the coking receptacle is discharged into and beneath'the surface of the liquid-body of oil maintained in the lower end of tower 4 through connections 7 and 8, the oil stock to be coked is introduced into the liquid body of oil maintained in the lower end of tower 4 through connection 9, the

vapor mixture from the upper end of tower 4: is discharged through dephlegmators 10 and 11 into the lower end of fractionating tower 12, the vapor mixture from the upper end of tower 12 is discharged through dephlegmator 13 either to the condenser 14 or through the fractionating tower 15 and the dephlegmator 16 to the condenser 14, and a coke product is periodically discharged from the coking receptacle 3. Condenser 14 is arranged to discharge into receiver 17 from which the condensate product is discharged through connections 18 and 19 and from which uncondensed vapors and gases are discharged through connection 20.

- The hot oil pump 6, as well as the hot oil pumps 21 and 22, may, with advantage, be of the type described and illustrated in Patent No. 1,701,198 issued February 5, 1929, to the Sinclair Refining Company, on'the application of Thomas de Colon Tifli't.

' The vapor phase cracking operation proper may be carried out, for example, as described in application Serial No. 198,621 filed June 13, 1927, by Harry L. Pelzer, and the hot vapor mixture from the digesting drums discharged directly into the coking receptacle, or the digesting drums may be omitted and the hot vapor'mixture from the heater proper may be discharged directly into the coking receptacle, as in the apparatus illustrated.

Connections 23, 24 and 25 are provided for supplying steam to the heater 2, to the lower end of the coking receptacle 3, and to the lower end of the baflied tower 4, respectively. Condenser 26 is provided for use in steaming out the coking receptacle 3. Connection 30 is provided-for by-passing the coking receptacle 3 while discharging coke charges from and'while cleaning this receptacle.

The type of bafiied tower 4 illustrated is of special value in carrying out the invention.

This tower comprises three parts; a lower part adapted for the maintenance of a liquid body of oil to which the raw stock to be coked is supplied through connection 9, into which the hot vapor mixture from the coking voperation proper is discharged through a submerged inlet connection 8, and from which the oil mixture supplied to the coking operation proper is withdrawn through connection 26; an intermediate part provided with open plate bafiles 27 adapted for providing limited fractionation with a minimum danger of obstruction through accumulations of heavy oil or semi-solid cokey material; and an upper part provided with bubble plates 28 or other equivalent baffling means adapted for provid ing relatively close fractionation. The baflled tower at is, with advantage, lagged or thermalnewnesly insulated. A refluxing medium may be introduced into the upper end of the bafiled tower 4 through connection 29, or a refluxing.

medium may be supplied to the upper end of baifled tower 4 from either or both of the dephlegmators 10 and 11, or refluxing media may be supplied in both ways at the same time. Dephlegmator 10 is provided with coils through which the oil stock .to be coked, or part of it, may be passed in indirect heat exchanging relation with the vapors escaping from the upper end of the baflled tower 4 before introduction into the lower end of the bafied tower 4 through connection 9. This oil stock is supplied by means of pum 31 through connection 32. The operation 0 the dephlegmator 10 may be controlled, for ex ample, by regulated by-passing of this oil stock through connection 33. Dephlegmator.

11 is provided with 'coils through which we? 2r or some otherextraneous cooling medium m. .y be circulated. The several refluxing means provided may be used conjointly or separately, and if used separately those not used may be omitted as part of the apparatus. The dephlegmator 11 may be used, for example, tosupplement the refluxing action either of a refluxing medium introduced through connection 29 or of the dephlegmator 1Q. Any excess of the oil mixture accumulating in the lower end of the tower 4 may be discharged through connection 34 and cooler 35. The condensate or part of the condensate produced in the fractionating tower 12, or'the condensate or part of the condensate produced in the fractionating tower 15, or a mixture of these condensates, may be supplied to the 'upper end of the baflled tower 4 through connection 29 as a refluxing medium, either through connection 36 or, and usually more advantageously, through cooler 37, by means of either or both of the pumps 21 and 22 and the connections illustrate V Condensate produced in the fractionating tower 12 or condensate produced in the fractionating tower 15 or a mixture of these condensates is supplied to the vapor phase cracking heater 2 through connections 38 and 1 by means of the pump 21 or the pump 22 or both of these pumps. Additional. raw stock may also be supplied to the cracking heater 2 through connections 39 and 1 by means of pump 40. When the vapor mixture from the afiled tower 4 is passed successively through the fractionating towers 12 and 15, the U. G. I.

, carbon residue test of the condensate from the fractionating tower 12 is normally higher than that of the condensate from the fractiona-ting tower 15, and the U. G. 1. carbon residue test of the stock supplied to the vapor phase cracking operation, may be controlled by regulating the proportion of these condensates supplied to the vapor phase cracking operation in a mixture of. the two; for example, to decrease the U. G. I. carbon residue fluxing medium in the tower 4 may be increased and the proportion of the condensate from the fractionating tower 15 in a condensate mixture suppliedto the vapor phase cracking operation increased. The'U. G. 1. carbon residuetest of the stock supplied to the vapor phase cracking operation may also be limited, for example, by the supplemental introduction of a raw stock of relatively low U. G. 1. carbon residue test through connection 39. When the U. G. 1. carbon residue test of the condensate mixture supplied to the vapor phase cracking operation from the fractionating operation is relatively low, a raw stock of relatively high U. G. 1. carbon residue test may be introduced through connection 39 in. amount limited so that the U. 'G. 1. carbon test of the resulting stock mixturev does not exceed the desired limit. The fractionating towers 12 and 15 may be of any conventional type, the so-called bubble plate type for example, adapted for providing close fractionation. The operation of these fractionatingtowers may be controlled by the regulated introduction-of refluxing media through connections 41 and 42, or by means of the dephlegmators 13 and 16, or by both of these means conjointly. Dephlegma tors 13 and 16 are provided with coils through which water or some other extraneous cooling medium may be circulated. Part of the condensate produced in the fractionating tower 15 may be supplied to the upper 1 end of the. fractionating tower 12 as a re fluxing medium, or some similar fraction may be so supplied to the upper end of the fractionating tower 12 as a-refluxing medium. Part of the condensate product may be supplied to the upper end of the tower 15 as a. refluxing medium, or some similar fraction may be so supplied to the upper end of the fractionating tower 15 as a refluxing medium, through connection 42 by means of pump 43. Any excess condensates produced in the fractionating tower 12 or 15 may be discharged through connection 44 and cooler 45 or through connection 46 and cooler 47 respectively. Connection 48 is provided for bafiied tower 4 at a fixed rate approximating 200 allons per hour and a gas oil condensate pro need in the fractionating tower 12 is introduced into the-upperend of the bafiied tower 4 through connection 29 at a rate ap proximating 250 gallons er hour regulated to maintain the ravity 0 the residual stock mixture pumped throughv connection 5 to the coking receptacle close to 10 A. P. I. The fractionating tower 12 is operated to produce a heavy gas oil reflux condensate and the operation of the fractionating tower 15 is regulated so that the condensate produced from'the vapors escaping from the fractionating tower 15 boiling range, say, 410 F. end-point. The stock; mixture produced by adding the condensate produced in the fractionating tower 15 to that part of thecondensate produced in the fractionatingtower 12 not supplied to the bafiled tower 4 as a refluxing medium has a U. G. I. carbon residue test not exceeding 03% and is supplied to the vapor phase cracking heater 2.

Comparing the operation just outlined to an operation in which no refluxing medium is supplied to the upper end of the bafiled tower 4, approximately 400 gallons per hour of reduced crude may be supplied to the bafiied tower 4 to maintain the residual stock mixture of the desired gravity and the U. G. I. carbon residue test of the condensate produced in the fractionating tower 12, under these conditions, may be as high as 2.0% or higher. Further,.the operation embodying. the invention is free from difiiculty due to the formation of coke in thebaflled tower 4.

The operation of the vapor phase cracking heater 2 and the coking receptacle 3 being carried out as described in application Serial No. 340,996, mentioned-above, reduced crude is pumped through the coils in the dephlegmator 1O and then introduced into the lower endof the baflied tower 4, all of the reduced crude being passed throughthe coils in the dephlegmator- 10, at a rate approximating 250-300 gallons per hour and the operation of the dephlegmator 11 is controlled to maintain the gravity of the residual stock mixture pumped from the lower end of the baflied tower 4 to the coking receptacle 3 through connection 5 close to 10 A. P. I. The vapors from the fractionating tower 12 are passed directly to the condenser and the operation of this fractionating tower is controlled so that the condensate produced in the condenser is a gasoline product of the desired boiling range, say, 410 F. end-point. The condensate produced in the fractionating tower 12 is of U. G. I. carbon residue test not exceeding 0.3% and is supplied to the vapor phase cracking heater.

The type of baflied tower illustrated in the accompanying drawings, the baflled tower 4, is of special value in combination with cokis a gasoline of the desired ing apparatus in which the heat for coking is internally supplied by the direct introductlon of the hot vapor mixture from a vapor phase cracking operation, for the production of a clean, or substantially clean, vapor fraction. \Vitha tower'of the type illustrated, operated as previously described, it is possible to produce residual stock mixtures containing as little as 1% boiling off below 600 F. at atmospheric pressure and at the same time to produce a condensate from the escaping vapor fraction, including the highest boiling components of the escaping vapor fraction, with an end boiling point as low as 580 F. at atmospheric pressure. an ordinary open baflled towerin this operation, it is not unusual for the residual stock mixture to contain as much as 40% boiling ofi' below 600 F. and for the vapor fraction to include components having boiling points as high as 7 00 F. or higher.

I claim: Y 1. In a combined vapor phase'cracking' and .coking operation, the improvement which comprises subjecting oil stock having a carbon residue content as determined by Using the U. G. I. gas oil distillation test not exceeding about 0.3% to a a vapor phase cracking operation, subjecting a liquid oil mixture to a coking operation in which said oil'mixture is coked by direct heat exchange with the hotvapor mixture from the vapor phase cracking operation, discharging the hot. .vapor mixture from the coking operation into and beneath the surface of a liq.-

uid body of oil maintained in the lower end of a bafl'led tower subjecting the vapors to a refluxing operation in said bafiled tower, introducing the raw oil stock to be coked into the lower end of the baffled tower to mingle 'with said liquid body of oil therein and supplying the resulting composite oil mixture from said liquid body of oil including condensate formed in said refluxing operation to the coking operation, subjecting the vapors escaping from the upper end of the bafiled tower to a fractionating operation, discharging vapors escaping from the fractionating operation to a condenser and condensing a distillate product therein, introducing condensate separated from the ,vapors in the fractionating operation into the upper end of the baflled tower as a refluxing medium, and supplying condensate separated from the va- .pors in the fractionating operation to the vapor phase cracking operation.

2. In a combined vapor phase cracking and coking operation, the improvement which comprises subjecting oil stock having a carbon residue content as determined by the U. G. I. gas oil distillation test not exceeding about 0.3% to a vapor phase cracking operation, subjecting a liquid oil mixture to a coking operation in which said oil mixture is coked by direct heat exchange with the hot vapor mixture 'from the vapor phase" cracking operation, discharging the hot vapor mixture from the coking operation into and beneath the surface of a liquid body of oil maintained in the lower end of a baflied tower, subjecting the vapors to a refluxing operation in said baflled tower, introducing the raw 'oil stock to be coked into the lower end of the baflied tower to mingle with said liquid body of oil therein and supplying the resultin composite oil mixture from said liquid ody of oil including condensate formed in said refluxing operation to the coking operation, subjecting the vapors escaping from the upper'end of the baflied tower to a fractionating operation, discharging vapors escapin from the fractionatmg operatlon to a con enser and condensing a distillate product therein, introducin condensate separated from the vapors in the fractionatin operation into the upper end of the baflie tower as-a refluxing medium,

regulating the introduction of said refluxing medium to maintain the oil mixture supplied from said liquid oil body in the baflied tower to the coking operation of gravity not substantially exceeding 15 degrees A. P. I. and supplying condensate separated from the vapors in the fract-ionating operation to the vapor phase cracking operation.

3. In a combined vapor phase cracking and coking operation, the improvement which comprises subjecting oil stock having a carbon residue content as determined by the U. G. I. gas oil distillation test'not exceeding about 0.3% to a vapor phase cracking operation, subjecting a liquid oil mixture to a cokin operation in which said oil mixture is coked by direct heatexchange with the hot Vapor mixture from the vapor phase cracking operation, discharging t e hot-var mixture from the coking operation into" and beneath the surface of a liquid body of oil maintained in the lower end of abaflled tower, subjectingthe vapors to a refluxing operation in said bafiied tower, introducing the raw oil stock to be coked into the lower end of the baflled tower to mingle with said liquid body of oil therein and supplying the resulting composite oil mixture from said liquid body of oil including condensate formed in said refluxing operation to the coking operation, subjecting the vapors escaping from the upper end of the baflled tower to a fractionating operation, discharging vapors escaping from the fractionating operation to a condenser, passing raw oil stock to be coked in indirectheat exchanging relation with the vapors escaping from the upper end of the baflied tower before introduction into the lower end of the baflied tower and supplying condensate so produced to the baflied tower as a refluxing medium, and supplying condensate separated from the upper end of the ba gas oil distillation test not exceedis coked by direct heat exchange with the hot vapor mixture from the vaponphase cracking operation,-discharging the hotvapor mixture from the coking operation into and beneath the surface of a liquid body of oil maintained in the lower -end of a baflied tower, subjectin the vapors to a refluxing operation in said baflied tower, introducing the raw oil stock to be coked intothe lower end of the baflled tower to mingle with said liquid body of oil therein and supplying the resultin composite oil ,mixture from said liquid odyof oil including condensate formed in said refluxing operation to the coking operation, subjecting the vapors escaping from the upper end of 'thellbaflled tower to a fractionating operation, dischargingvapors escaping from the fractionating operation to a condenser, assing raw oil stock to be coked 'in indirect eat exchanging relation with the valpors escaping from the ed tower before introduction into the lower end of the baflied tower and supplyin condensate produced from the vapors by t e cooling action of the raw oil stock to the baflled tower as a refluxing medium, regulatin the supply ofsaid re uxin medium to maintain the oil mixture sup lie from said liquid body of oil in the ba ed tower to the coking operation of gravity not substantially exceeding 15 degrees A. P. I. q

5. In a combined vapor phase cracking and coking operation, the improvement which comprises subjecting oil stock having a carbon residue content as determined by the U.

G. I. gas oil distillation test not exceeding about 0.3% to a va or phase cracking operation, subjecting a liquid oil mixture to a cok in operation in which said oil mixture is co ed by direct heat exchange with the hot vapor mixture from the vapor phase crackin operation, discharging the hot vapor mixture fromthe coking operation into and beneath the surface of a liquid body'of oil maintained in the lower end ofa baflled tower, subjecting the vapors to a refluxing operation in said bafiied tower, introducing the raw oil stock to be coked into the lower end'of the baflied tower to minglewith said liquid body of oil therein and supplying'the resulting composite oil mixture fromsaid liquid body of oil including condensate formed ,in said refluxing operation to the coking operation, subjecting the vapors escaping tower and supplyingcondensate so produced to the bafiled tower as a refluxing medium.

6. In combination ,in an'oil coking apparatus in which heat for coking is internally supplied by the direct introduction of a hot 'vapor mixture from a vapor-phase cracking operation, a heating conduit, means for supplying oil thereto, means for heating said conduit to a temperature suflicient to eflect con-' version of the oil therein in the vapor phase, a

coking receptacle and a connection from said heating conduit to said coking receptacle, a scrubbing tower comprlsing a. shell, a series of open baflles in the intermediate part, a

series of bubble plates in the upper part, means for supplying a refluxing medium to the upper part, means for introducing vapors from the coking receptacle into the lower part, and means for introducing a heavy oil to and for intimately contacting said heavy oil and vapors in the lower part, means for s upgilyin liquid oil from the lower part of $9.1 scru bing tower to the coking receptacle, a fractionating tower, means for dischar ing vapors from the upper part of said scrubbing tower to the fractionating tower, and a connection for returning liquid from the lower part of said fractionating tower to said heating conduit.

7 In a combined vapor-phase cracking and coking o eration, the improvement which comprises su jecting oil sto'ck having a cerbon residue content as determined by the U.

G. 1. gas oil distillation test not exceeding about 0.3% to a vapor-phase cracking operation, subjecting a liquid oil mixture to a cokin operation in which said oil mixture is co ed by direct heat exchange with the hot vapor mixture from the vapor-phase cracking operation, discharging the hot vapor mixture from the coking operation into and beneath the surface of a liquid body of oil.

maintained in the lower end of a bafiied tower, subjecting vapors passing through the baflied tower to a refluxing operation therein, in-

troducin' raw oil stock to be coked into the.

lower en of the bafiled tower to mingle with said liquid body of oil therein, supplying the resulting composite oil mixture from said liquid body of oil including condensate. formed in said refluxing operation to the cok ing operation, subjecting the vapors escaping from the upper end of the baflie tower to a fractionating operation, discharging vapors escaping from the fractionating operation to a condenser and condensing a distillate product therein, controlling the refluxing operation and the fractionating operation so as to separate from the vapors in the fractionating operation a condensate having a carbon residue content as determined by the U. G. I. gas oil distillation test not exceeding about 0.3%, and supplying the condensate thus separated from thevapors in the frac-' tionating operation to the vapor-phase cracking operation. I

- 8. In a combined vapor-phase cracking and coking operation, the improvement which comprises subjecting oil stock having a carbon residue content as determined by the U. G. 1. gas oil distillation test not exceeding about 0.3% to a vapor-phase cracking operation, subjecting a liquid oil mixture to a coking operation in which said oil mixture is coked by direct heat exchange with the hot vapor mixture from the vapor-phase cracking operation, discharging the hot vapor mixture from'the coking operation into and beneath the surface of a liquid body of oil maintained in the lower end of a baflled tower, subjecting vapors passing through the bafiled tower to a refluxing operation therein, introducing raw oil stock to be coked into the lower end of the baflled tower to mingle with said liquid body of oil therein and supplying the resulting composite oil mixture from said liquid body of oil including condensate formed in said refluxing operation to the coking operation, subjecting the vapors escaping from the upper end of the bafiied tower to a fractionating operation, dischargin the vapors escaping from the'fractionating operation to a condenser and condensing a distillate product therein, controlling the refluxing operation and the fractionating operation to maintain the oil mixture supplied from said liquid body in the .baflled tower to the coking operation of gravity not substantially exceeding 15 A. P. I., and to separate from the vapors in the-fractionating operation a condensate having a carbon residue content as shown by the U. G. I. gas oil distillation test not exceeding about 0.3%, and supplying condensate thus separated from the vapors in the fractionating operation to the vapor-phase cracking operation. 9. In' a combined vapor-phase cracking and. coking operation, the improvement which comprises subjecting oil stock having a carbon residue content as determined by the U. G. I.. gas oil distillation test not exceeding about 0.3% to a vapor-phase cracking operation, subjecting a liquid oil mixture to a coking operation in which said oil mixture is coked by direct heat exchange with the hot vapor mixture from the vapor-phase cracfing operation, discharging the hot vapor mixture from the coking operation into stock to be coked into the lower end of the bafied tower to mingle with saidliquid body of oil therein and supplying the resulting composite oil mixture fromsaid liquid body of oil including condensate formed in the refluxing operation to the coking operation, subjecting the vapors escaping from the upper end of the baflled tower to a fractionat ing operation, discharging-vapors escaping from the fractionating operation to a condenser and condensing the distillate product therein, regulating the passage of said cooling medium'in' heat exchange with the vapors in the upper end of'the baflled tower and simultaneously regulating the fractionating operation to maintain the oil mixture supplied from said liquid body in the baflied tower to the coking operation of gravity not exceeding 15 'A. P. 1., and to separate from the vapors in the fractionati'ng operation a condensate having a carbon residue content as determined by the U. G. I. gas oil distilla tion test not-exceeding about 0.3%, and supplying condensate thus separated from the vapors in the fractionating operation to the vapor-phase cracking operation.

10. In a combined vapor-phase cracking and coking operation, the improvement which comprises subjecting oil stock having a carbon residue content as determined by V the U. G. I. gas oil distillation test not exof the 'bafiied tower, introducing raw oil stock to be coked into the lower end of the baflled tower so as to mingle withsaid liquid.

wit

ing composite oil mixture fromsaid li uid bod of oil including condensate forme in sai refluxing operat on to .the coking operation, subjecting the va ors escaping from the upper end of the 'ba edtower to a fractionating operation, discharging the vapors escaping fromithe'fractionating operat1on toa condenser and condensing a distill-ate producttherein, controllin the refluxing opera tion and the fractionatmg operation so as to of oil therein. and intimately contact. the hot vapor mixture discharged from. the coking operation, supplying the resultmaintainthe oil mixture supplied to the coking operation 'from said liquid body in the baflled tower of gravity not substantially exceedin 15 A. ,P. I. andso asto separate from t e vapors in the fractionating operation a condensate having a carbon residue content as determined by the U.'. G. 1. gas oildistillation test not exceeding about 0.3%, and supplying condensate thus separated from the vapors in the fractionating operation to the vapor-phase cracking operation.

11. In a combined vapor-phase cracking and coking o eration, the improvement comprising sub ecting oil stock having an end boiling point of approximately 580 F.

at atmospheric pressure to a vapor-phase cracking operation, subjecting a liquld oil mixture to a coking operation in which said 'oil mixture is coked by direct heat exchange with the hot vapor mixture from the'vaporphase cracking operation, discharging the hot vapor mixture from the coking operation into the lower end of a bafiled tower, subecting vapors passing through the bafiled tower to a refluxing operation therein, maintaining a body of liquid oil in the lower end of the baflled tower, introducing raw oil stock to be coked into the lower end of the baflled tower so as to mingle with said liquid body of oil therein and intimately contact with the hot vapor mixture discharged from the coking operation, supplying the resulting composite oil mixture from said liquid body of oil including condensate formed in said refluxing operation to the cokin operation, subjecting the vapors escaping from the upper end of the baflled tower to'afractionating operation, discharging vapors escaping from the fractionating operation to a condenser and condensing a distillate product therein, controlling the refluxing operation and the'frac-tionating operation so as to maintain'the oilmixture supplied to the coking operation from the liquid body in the baf- -fled'towersubstantially free from oil boiling below about 600F. at atmospheric pressure and so as to separate fromthe vapors in'thefra'ctionating operation a condensate having mately 580]F. at atmospheric pressure, and supplying the condensate thus separated from the vapors in the fractionating operation to an end boiling point of approxi-v the vapor-phase cracking-o 'IBJJIOH, In testimony whereof I a x my signature.

' EUGENE O. HERTHEL.

CERTIFICATE OF CORRECTION.

, Patent No. 1,810,048. Granted June 16,1931, to

EUGENE o. HERTHELQ It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: 7 Page 1, line 12 for the word "usually" read unusually; and that the said Letters Patent should be read with this correction therein that the same may'conform to the record of the case in the Patent Office.

Signed and sealed this 4th day of August, A. D. 1931.

W n. A. Kinnan, (Seal) Acting Commissioner of Patents,

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