US1988842A - Conversion of hydrocarbon oil - Google Patents

Description

Jan. 22, 1935.

J. B. HEID 1,988,842

CONVERSION OF HYDROCARBON on. I

FiledMay 31, 1932 FRACTIONATOR CONDENSER 2| COKING CHVBMBER- FURNACE 62 CONDENSER INVENTOR JACOB BENJAMIN HEID ATTQRN Patented Jan. 22, 1935 UNITED I STATES CONVERSION OF HYDBOCABBON OIL Jacob Benjamin Held,

Chicago, 11]., assignor to Universal Oil Products Company, Chicago, 111., a corporation of Delaware Application May 31, 1932, Serial No. 614,422

2 Claims.

This invention relates to the conversion of hydrocarbon oil and more particularly refers to an improved process and apparatus for the conversion of hydrocarbon oil, at substantial super-atmospheric pressure, to produce maximum yields of light distillate, such as motor fuel of high antiknock value, accompanied by reduction of the residual conversion products to coke, at reduced pressure, assisted by the introduction into the coking zone of highly heated intermediate products of the operation. I

A specific embodiment of the invention may comprise subjecting hydrocarbon oil to conversion temperature at super-atmospheric pressure in a heating coil and communicating enlarged" reaction chamber, in which reaction chamber residual liquid and vaporous' conversion products separate, withdrawing said residual liquid from the reaction chamber and introducingitinto a re- 20 duced pressure coking zone, subjecting vapors from the coking zone to fractionation, whereby their high boiling components are condensed as heavy reflux condensate, returning the heavy reflux condensate to said heating coil for further conversion, subjecting vapors remaining uncondensed by said fractionation to further fractionation whereby additional components, boiling above the end-point oi the desired light distillate product, are condensed as light reflux condensate, subjecting said light reflux condensate to further conversion in a separate heating coil at a higher temperature than that employed in the first mentioned heating coil, and introducing the highly heated light reflux into direct contact with the material undergoing coking in the coking zone.

To further-assist coking and devolatilization, uncondensahle gas, produced by the process, may be reheated to a high temperature and introduced into direct contact with the residual material in the coking zone. The uncondensable gas may be separately heated or may be heated together with the light reflux condensate from the coking operation, permitting, in the latter case, the use of higher temperatures in the light reflux heating coil.

The attached diagrammatic drawing illustrates one specific form 01' apparatus embodying the features oi the present invention and a more de- 60 Qtailed description of the operation of the process 01 the invention is included in the following description or the drawing. Raw oil charging stock for the system is supplied through line 1 and valve 2 to pump 3 from which it is fed through line 4 andmaypassthroughline 5,valve6 andline'lto heating coil 8. All or any desired portion of the raw oil, instead of passing direct to heating coil 8 may be directed to line 4 through line 9 and valve 10 to i'ractionator 11 wherein it is preheated by direct contact with the vaporous prodi; ucts in this zone, serving to assist their iractiona tion and passing, together with the reflux condensate removed from the vapors, through line 12 and valve 13' to pump 14'. Pump 14L supplies the reflux condensate and preheated raw oil or i reflux condensate alone, in case no raw oil is supplied to iractionator 11, through line 7 and valve .12 to heating coil 8.

The oil supplied to heating coil 8 is heated to the desired conversion temperature by means of 2 heat supplied from a furnace 13 of any suitable form and the heated oil is discharged through line 14 and valve 15 into reaction chamber 16.

Reaction chamber 16, like heating coil 8, is preferably maintained at substantial super-at- 20 mospheric pressure and the reaction chamber is preferably insulated to prevent the excessive loss of heat, so that conversion 01' the products from heating coil 8 may continue in this zone. Vaporous and residual liquid conversion products 26 are separated in chamber 16.

Vaporous conversion products pass from chamber 16 through line 17 and valve 18 to fractionation in tractionator 11 wherein their insumciently converted heavy components are condensed as reflux condensate and whereirom they are returned, as already described, to heating coil 8 for further conversion.

Vaporous products of the desired end-boiling point, remaining uncondensed in Iractionator 11, 1 arewithdrawn irom-..the upper portion oi. the fractionatonthrough line 19 and valve 20, are subjected to condensation and cooling in condenser 21, from which distillate and uncondensable gas passes through line 22 and valve 23 40 to be collected in receiver 24. Uncondensable gas may be releasedi'rom the receiver through line 25 and valve 26. Distillate is withdrawn from the receiver through line 2'1 and valve 28.

Residual liquid is withdrawn from chamber 16 4 through line 29 and valve 30 and is introduced into coking chamber 31, which is preferably operated at substantially reduced pressure relative to that employed in chamber 16 and wherein the vresidual oil is reduced to substantially dry coke,

by virtue of the latent heat distillation accompa y the reduction in pressure and with the assistance of othermeans, which will be later described. It will beunderstood that one or a plurality oi coking chambers may be employed, as

desired, a plurality being preferred, although only one is illustrated in the drawing. When a plurality of coking chambers is used, they may be operated either simultaneously or alternately, providing additional space for the accumulation of coke and thus permitting prolonged operation of the process.

Vaporous products are withdrawn from coking chamber 31 through line 32 and valve 33 to fractionation in fractionator 34 wherein their high boiling components are condensed as heavy reflux condensate, which is withdrawn from the lower portion of the fractionator through line '35 and valve 36 to pump 37, by means of which this heavy reflux is returned through line 38, valve 39 and line '7 to heating coil 8, for further conversion.

Vaporous products remaining uncondensed in fractionator 34 are withdrawn through line 40 and valve 41 to further fractionation in fractionator 42. Vapors of the desired end-boiling point, remaining uncondensed in fractionator 42, are withdrawn through line 43 and valve 44, are subjected to condensation and cooling in condenser 45, from which distillate and uncondensable gas is withdrawn through line 46 and valve 47 to collection in receiver 48. Uncondensable gas may be released from receiver 48 through line 49, line 50 and valve 51. Distillate is withdrawn from the receiver through line 52 and valve 53.

The components of the vapors, subjected to fractionation in fractionator 42 boiling above the desired end-point of the distillate collected in receiver 48, are condensed within this fractionator as a light or secondary reflux condensate from the coking operation. This product is withdrawn from fractionator 42 through line 54 and valve 55 to pump 56 from which it is 'fed through line 57, valve 58, line 59 and valve 60 to heating coil 61, wherein it is heated by means of heat supplied from furnace 62, of any suitable form, preferably to a higher temperature than that employed in heating coil 8, by means of which said light reflux cendensate is subjected to further conversion for the production of additional yields of desirable light distillate such as high antiknock motor fuel,

The highly heated products from heating coil 61 are discharged through line 63 and valve 64 into coking chamber 31, preferably entering the lower portion of this zone so that they may be directly contacted with and pass upward through the mass of residual material undergoing coking, serving as a heat carrying medium to assist the coking operation.

To further assist the coking operation, uncondensable gas from receiver 24, withdrawn through line 65 and valve 66 and/or uncondensable gas from receiver 48, withdrawn through line 49 and valve 67, is directed to -pump or compressor 68, by means of which it may be fed through line 59, valve 69 and valve 60 to heating coil 61, together with light reflux condensate from fractionator 42, serving as additional heat carrying medium to permita greater total quantity of heat bein supplied to the residual material and, when desired, permitting the use of higher temperature in heating coil 61 than would be suitable without dilution of the light reflux condensate.

It is within the scope of the invention to employ a separate heating coil for reheating gas from receiver 24 or receiver 48, or both, prior to its introduction into the coking zone, although this provision is not illustrated in the drawing.

Uncondensable gas from receiver 24 may be utilized to start the coking operation, this product being pumped through heating coil 61 and the heated gas discharged through the bed of residual material in chamber 31 until equilibrium operating conditions are reached and a suificient quantity of secondary reflux condensate is formed and collected in fractionator 42, to augment or supplant the uncondensable gas from receiver 24. It is also within the scope of the invention to utilize a suitable oil from an external source to start the coking operation, either alone or in conjunction with uncondensable gas from receiver 24. This extraneous oil, which may comprise, for example, naphtha, pressure distillate bottoms, kerosene distillate or other suitable oil, preferably of low boiling characteristics, may be supplied through line '70. valve 71 and line 54 to pump 56, by means of which it is fed through line 57, valve 58, line 59 and valve 60 to heatin coil 61, where it is heated to the temperature required to insure coking of the residual material in chamber 31, upon its introduction to this zone, and preferably the conditions employed in heating coil 61, when such extraneous oil is utilized, are suitable for the conversion or reforming of this material to produce additional yields of high antiknock quality motor fuel.

The heating coil wherein the raw oil charging stock, reflux condensate from the cracking operation and heavy reflux condensate from the coking operation are treated, employs a conversion temperature which may range, for example, from 800 to 950 F. with superatmospheric pressure which may range, for example, from to 500 pounds, or more, per square inch. Substantially this same range of pressures may be employed in the reaction chamber and may be either substantially'equalized or reduced in the succeeding fractionating, condensing and collecting portions of the system. The heating coil, through which the heat carrying medium for the coking operation is passed, utilizes a conversion temperature which may range, for example, from 900 to 1100 F. The pressure employed in this zone may range from substantially atmospheric to super-atmospheric pressures as high as 800 pounds, or thereabouts, per square inch. Substantially reduced pressure is preferred in the coking zone, relative to that employed in the reaction chamber ranging, for example, from .100 pounds, or thereabouts, per square inch, downto substantially atmospheric pressure. The fractionating, condensing and collecting equipment of the coking portion of the system may utilize pressures substantially equalized with or reduced, relative to that employed in the coking zone.

gravity Mid-Continent residual oil which is subjected, together with reflux condensate from the cracking portion of the system and heavy reflux condensate from the primary fractionator of the coking portion of the system, to a temperature of about 900 F. at a superatmospheric pressure of approximately 275 pounds per square inch. This, pressure is substantially equalized in the reaction chamber and in the succeeding fractionating, condensing and collecting portions of the cracking system. Residual oil is withdrawn from the reaction chamber at a sufliciently rapid rate to preclude accumulation of any substantial body of this material in the reaction zone and is introduced into a coking zone operated at a superto an octane number of approximately 74 and about 85 pounds of petroleum coke having a volatile content of about 7 percent. The only other product is uncondensable gas which, due to recirculation and reheating of this product, is of greater volume, higher hydrogen content and lower calorific value than the gas ordinarily produced by cracking and is more suitable for use as fuel.

I claim as my invention:

1. In a process for the conversion of hydrocarbon oil wherein the oil is subjected to conversion temperature at superatmospheric pressure in a heating coil and communicating reaction chamber. from which vaporous and residual liquid conversion products are separately withdrawn and the latter introduced into a reduced pressure coking zone, the" improvement which comprises dephlegmating the vapors fron .the reaction chamber and returning resultant reflux to said coil, subjecting vaporous products from the coking zone to primary and secondary fractionation whereby primary and secondary'reflux condensates are formed, returning said primary reflux condensate to said heating coil for further conversion, subjecting said secondary reflux conden sate to a higher conversion temperature in a separate heating coil and then introducing it into direct contact with the residual material in the coking zone, whereby to assist reduction of the latter to coke, and finally condensing as a product of the process the vapors uncondensed by said secondary fractionation.

2. In a process for the conversion of hydrocarbon oil wherein the oil is subjected to conversion temperature at superatmospheric pressure in a heating coil and communicating enlarged reaction chamber wherein vaporous and residual "liquid conversion products separate, vapors from the reaction chamber are subjected to fractionation, their heavy components, condensed by tractionation, are returned to the heating coilfor further conversion, the fractionated vapors are subjected to condensation and the resulting distillate and uncondensible gas collected, the improvement which comprises withdrawing residual liquid from the reaction chamber and introducing itinto a reduced pressure coking chamber, subjecting vaporous products from the coking zone to primary and secondary fractionation whereby primary and secondary reflux condensates are formed, returning-said primary reflux condensate to the aforementioned heating coil for further conversion, subjecting the fractionated vapors to condensation, collecting the resuiting distillate and uncondensible gas, subjecting said secondary reflux condensate and uncondensible gas from the system to reheating, at higher temperature than that utilized in the aforementioned heating coil, and introducing the highly heated materials into direct contact with the residual material in the coking zone, whereby a to assist its reduction to coke.

JACOB BENJAMIN HEID.

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