US2016781A - Conversion of hydrocarbon oils - Google Patents

Description

Oct. ,8, 1935. Y J H 2,016,781

CONVERS ION 0F HYDROCARBON OILS Filed May 4, 1935 FUR/35465 14 ATTORN EY.

Patented Oct. 8, 1935 UNITED STATES CONVERSION OF HYDROCARBON OILS Jacob Benjamin Heid, Ghicago, 111., assignor to Universal Gil Products Company, Chicago, Ill a corporation of Delaware Application May 4, 1933, Serial No. 669,317

ill Claims. (Cl. 196-49) This invention particularly refers to an improved process and apparatus for the conversion of hydrocarbon oils wherein the raw oil charging stock to be subjected to conversion is first separated into relatively low-boiling and high-boiling fractions each of which are subjected to conversion under independently controlled conditions of elevated temperature and superatmospheric pressure While the insufficiently converted interm mediate products of the process are subjected to further conversion, together with said relatively high-boiling fractions of the raw oil charging stock.

A more specific embodiment of the present in- 15 vention may comprise subjecting a hydrocarbon oil comprising the charging stock for the process to heating in a heating coil, introducing the heated oil into a separating chamber wherein its relatively low-boiling fractions are vaporized and 20 separated from its higher boiling fractions which remain unvaporized, subjecting the resulting vapors to pyrolytic conversion in a separate heating coil, introducing the heated low boiling fractions into a separate vaporizing or reaction chamber 25 wherein the vaporous and residual liquid conversion products of the process separate, subjecting the vaporous conversion products to fractionation whereby their insufficiently converted components are condensed as reflux condensate, sub- 39 jecting fractionated vapors of the desired endboiling point to condensation, collecting the re-- sulting products, returning reflux condensate resulting from said fractionation of the vaporous conversion products of the process to independent- 35 1y controlled conversion conditions of elevated temperature and superatmospheric pressure in 7 another separate heating coil, introducing the heated oil from the last mentioned heating -coil into the same vaporizing or reaction chamber to 40 which the separately heated low-boiling fractions of the charging stock are supplied and subjecting said higher boiling fractions of the charging stock,

. which remain unvaporized in the first mentioned vaporizing chamber, to further conversion in the 45 last mentioned heating coil, together with the reflux condensate.

As an alternative method of operation to that above described which may be found desirable, particularly when the high-boiling fractions of 50 -the charging stock which remain unvaporized in the first vaporizing chamber are of a relatively heavy nature having optimum conversion conditions less severe than those to which it is desirable to subject the reflux condensate, all or 55 any desired portion of this material, instead of being subjected to conversion in the last mentioned heating coil together with the reflux condensate, may be commingled with the stream of heated conversion products from either of the two cracking coils of the process (depending upon 5 the conditions of treatment most suitable for the high-boiling fractions of the charging stock) whereby said high-boiling fractions of the charging stock are heated to the desired relatively mild conversion temperature, serving at the same time 10 as a means of cooling and retarding conversion of the more highly heated products with which they are commingled, prior to their introduction into the second vaporizing chamber.

As another optional feature of the present invention, a regulated portion of the residual liquid withdrawn from the second vaporizing chamber of the system may, when desired, be introduced, with or without prior cooling, into the stream of heated oil from the heating coil to which the reflux condensate is supplied, serving as a means of cooling and retarding conversion of the heated conversion products prior to their introduction into'the vaporizing chamber and being thereby subjected to further conversion under relatively mild conversion conditions.

The accompanying diagrammatic drawing illustrates one specific form of apparatus inwhich the process of the invention may be practiced.

Referring to the drawing, the raw oil charging stock to be treated is supplied through line I, valve 2 to pump 3 by means of which it is fed through line 4 and valve 5 into heating coil 6. The charging stock may, of course, be preheated in any well known manner, when so desired, prior to its introduction into heating coil 6, although, for

I the sake of simplicity, means for accomplishing this are not illustratedin the drawing. Heating coil 6 is located in a furnace I of any suitable form by means of which suflicient heat is supplied to the oil passing through the heating coil to effect its subsequent substantial vaporization in vaporizing chamber 10 to which the heated oil is supplied through line 8 and valve 9.-

Separation of the relatively low-boiling and high-boiling fractions of the charging stock is accomplished in chamber I0. The relatively lowboiling fractions of the charging stock, which are vaporized in chamber I 0, are withdrawn therefrom through line H and valve 12 to heating coil l3, wherein they are subjected to conversion by means of heat supplied from a furnace I4 of any suitable form, and the heated conversion products are discharged through line l5 and valveflt into a separate vaporizing chamber 11. Prefatmospheric pressure,

erably in order that it will not be necessary to utilize a pump or compressor for forcing the vapors from chamber In through heating coil I3, or in order to decrease the work required of such a pump or' compressor, a substantial superatmospheric pressure is employed in chamber Hi and in heating coil 6 although, when desired, heating and vaporization of the charging stock may be accomplished at substantially atmospheric or low superatmospheric pressure, in which case a pump or compressor of suitable form, not shown in the drawing, is interposed in line H.

Vaporizing chamber I! is a zone of separation for the vaporous and residual conversion products of the process and may be operated at substantially atmospheric or low superatmospheric pressure or, in case it is desired to subject the conversion products from the heating coils to continued conversion in this zone, a substantial superatmospheric pressure may be employed therein which, however, is not in excess of the pressure employed at the outlet from the cracking coil employing the lowest pressure in case the two cracking coils are operated under different pressure conditions.

The vaporous conversion products of the process are withdrawn from chamber through line l8 and valve I9 to fractionation in fractionator 20 wherein, by suitable fractionating means not shown in the drawing such as perforated pans, bubble trays, packing or the like, the insufficiently converted components of the vapors, boiling above the end-point of the desired final light distillate product of the process, are condensed as reflux condensate.

Fractionated vapors of the desired end-boiling point are withdrawn, together with uncondensable gas produced by the process, from the upper portion of fractionator 26 through line 2| and valve 22 and are subjected to condensation and cooling in condenser 23, from which the resulting distillate and uncondensable gas passes through line 24 and valve 25 to collection in receiver 26. Uncondensable gas may be released from the receiver through line 21 and valve 28. The distillate may be withdrawn from receiver 26 through line 29 and valve 30 to cooling and storage or to any desired furthertreatment. When desired, a regulated portion of the distillate collected in receiver 26 may be withdrawn therefrom through line 3| and valve 32 to pump 33 by means of which it is returned through line 34 and valve 35 to the upper portion of fractionator 20, to assist fractionation of the vapors in this zone and maintain the desired vapor outlet temperature, thereby controlling the end-boiling point of the final light distillate product of the process.

The reflux condensate formed within fractionator 26, as described, is withdrawn from the lower portion thereof through line 36 and valve 31 to pump 38 by means of which it is fed through line 39 and valve 40 to heating coil 4| for further conversion. The oil supplied to heating coil 4| is subjected therein to the desired conversion temperature, preferably at a substantial superby means of heat supplied from a furnace 42 of any suitable form, and the heated conversion products are discharged through line 43 and valve 44 into chamber H, to commingle therein with the conversion products from heating coil l3 and be subjected th rewith to the same subsequent treatment alre dy described.

Residual liquid remaining unvaporized in chamber I1 is withdrawn therefrom through line 45 and may pass through line 46, valve 41, cooler 48, line 49 and. valve 50 to storage or elsewhere,.

as desired or when desired, a regulated portion of this material may be directed through line 5|, valve 52, pump 64, line 65 and valve 66 into line 43, to commingle therein with the heated conversion products from heating coil 4|, serving to cool the same and being thereby reheated to a temperature at which relatively mild further conversion of the residual oil is accomplished. In case it is not desired to cool the residual oil from chamber prior to its introduction into line 43, the cooling coil may be by-passed by means of valve 53 in line 46 or, as a means of more accurately controlling the temperature of the residual'oil introduced into line 43, a portion of this product'from chamber may pass through cooler 48, as described, and another portion of uncooled oil may pass through valve 53 for blending with the cooled material.

The material'remainingunvaporized in chamber l6, which comprises the relatively high-boiling fractions of the charging stock, is withdrawn therefrom through line 54 and valve 55 to pump 56 wherefrom it is fed through line 51 and may pass through valve 58 in this line into line 39 and thence to heating coil 4|, for conversion -together with the reflux condensate from fractionator 20. However, as previously mentioned, in case it is not desired to subject the high-boiling fractions of the charging stock from chamber ID to conversion conditions as severe as those employed for the reflux condensate in heating coil 4|, this unvaporized residual oil may be fed from line 51 through line 59 and either through line 60 and valve 6| into line l5 or through line 62 and valve 63 into line 43, commingling in the line to which it is supplied with the heated oil from heating coil |3 or heating coil 4|, as the case may be, serving to partially cool and retard conversion of the products with which it is commingled and being thereby heated to a milder conversion temperature than that employed in heating coil 4|.

Preferably, the charging stock is subjected in the heating coil to which it is supplied, prior to its introduction into the vaporizing chamber, to a temperature below that=at which any extensive conversion of the charging stock will occur under the conditions of pressure and time employed in the heating coil and vaporizing chamber, the exact temperature employed depending, of course, upon the other conditions of treatment as well as the nature of the charging stock and ranging, for example, from 650 to 850 F., or thereabouts, with pressures ranging from substantially atmospheric to several hundred pounds per square inch at the outlet from the heating coil and in the vaporizing chamber. Conversion conditions employed at the outlet from the heating coil to which the reflux condensate -or reflux condensate and high-boiling fractions of the charging stock are supplied may range, for example, from 850 to 950 F., preferably with a substantially superatmospheric pressure of from to 500 pounds, or' more, per square inch. The heating coil to which the lowboiling vaporous fractions of the charging stock and any incidental vaporous conversion products from the vaporizing chamber aresupplied preferably employs a conversion temperature within the range of 900 to 1050 F., and the pres sure employed at the outlet from this heating coil may range, for example, from substantially atmospheric to 800 pounds, or more, per square inch, this pressure being either substantially equalized or reduced in the succeeding vaporizing or reaction chamber. The fractionating, condensing and collecting portions of the system may utilize pressures substantially equalized with or somewhat reduced relative to the pressure employed in the second vaporizing or reaction chamher.

As a specific example of one of the many possible types of operation which may be practiced in accordance with the features of the present invention in an apparatus such as illustrated and above described, the charging stock is a mixed base crude of about 36 A. P. I. gravity containing approximately 40% of gasoline with an endboiling point of 437 F. and of low anti-knock value. The charging stock is heated to a -temperature of approximately 700 F., and is discharged into a vaporizing chamber maintained at a superatmospheric pressure of approximately 600 pounds per square inch. The vaporous products from the vaporizing chamber are passed through a cracking coil where they are heated to a temperature of approximately 975 F., under a pressure substantially equalized with that in the vaporizing chamber. The highly heated vapors from the cracking coil are cooled, prior to their introduction into a secondary or reaction chamber, by the introduction of high-boiling fractions of the charging stock comprising the unvaporized oil from the first vaporizing chamber. The second vaporizing or reaction chamber is maintained at a superatmospheric pressure of about 350 pounds per. square inch. The vapors from the reaction chamber are subjected to fractionation and the resulting reflux condensate is supplied to another separate heating coil wherein it is subjected to a conversion temperature measured at the outlet from the heating coil of approximately 950 F., at a superatmospheric pressure of about 350 pounds per square inch. Unvaporized residual liquid is withdrawn from the reaction chamber and a regulated portion thereof is commingled with the stream of heated conversion products from the last mentioned heating coil, prior to their introduction into the reaction chamber.

An operation such as above described may yield, per barrel of charging stock, about 76% of motor fuel having an anti-knock value equivalent -to an octane number of approximately 78, about i 12% of heavy residual oil suitable for use as fuel, the remaining 12%, or thereabouts, being chargeable principally to uncondensable gas and loss.

In a modification of the operation above described by supplying the unvaporized high-boiling fractions of the charging stock to the last mentioned heating coil for conversion, together with the reflux condensate, the yield of motor fuel may be somewhat improved at the expense of the quality and quantity of the residual product of the process.

In either of the above operations the quality and quantity of the residual product may be increased at the expense of a somewhat decreased yield of motor fuel by returning less or none of the residual liquid from the reaction chamber to the stream of conversion products from the last mentioned heating coil.

I claim as my invention: 1. A process for the conversion of hydrocarbo oils which comprises heating a hydrocarbon oil charging stock and subjecting it to vaporization whereby its low-boiling fractions are vaporized and separated from its higher boiling non-vaporous fractions, subjecting said low-boiling vaporous fractions of the oil to conversion conditions within a heating coil"and introducing the products into an enlarged chamber wherein the vaporous and non-vaporous residual conversion products separate, subjecting the vapors to fractionation whereby their insuificiently converted components are condensed as reflux condensate, subjecting fractionated vapors of the desired endboiling point to condensation, collecting the resulting products, subjecting the reflux condensate formed by said fractionation of the vapors to further conversion in a separate heating coil and introducing the heated products from said separate heating coil into said enlarged chamber, and commingling said non-vaporous high-boiling fractions of the charging stock with the stream of hot conversion products passing from the lastmentioned heating coil to said enlarged chamber.

2. A hydrocarbon oil conversion process which comprises heating the charging oil to distillation temperature and separating therefrom a relatively light fraction and a heavier fraction, heating the light fraction to cracking temperature in a heating zone and then discharging the same into an enlarged zone, introducing at least a portion of said heavier fraction of the charging oil into the enlarged zone, separating vapors from residue in the enlarged zone, removing separated vapors from the enlarged zone and subjectingthe same tionated vapors.

3. The process as defined in claim 2, further characterized in that said portion of the heavier fraction of the charging oil, prior to introduction to the enlarged zone, is passed through said second heating zone in admixture with the reflux condensate.

4. A hydrocarbon oil conversion process which comprises heating the charging oil to distillation temperature and separating therefrom a relatively light fraction and a heavier fraction, heating the light fraction to cracking temperature in a heating zone and then discharging the same into an enlarged zone, separating vapors from residue in the enlarged zone, removing separated vapors from the enlarged zone and subjecting the same to fractionation, passing resultant reflux condensate through a second heating zone and subjecting the same therein to independently controlled cracking conditions of temperature and pressure, introducing the thus treated reflux condensate into the enlarged zone, commingling at least a portion of said heavier fraction of the charging oil with the heated reflux condensate passing from said second heating zone to the enlarged zone, and finally condensing the fractionated vapors.

5. A hydrocarbon oil conversion process which comprises heating the charging oil to distillation temperature and separating therefrom a relatively light fraction and a heavier fraction, heating the light fraction to cracking temperature in a heating zone and then discharging the same into of said heavier fraction of the charging oil into the heated light fraction discharging from the heating zone into the enlarged zone, separating vapors from residue in the enlarged zone, removing separated vapors from the enlarged zone and subjecting the same to fractionation, passing resultant reflux condensate through a second heating zone and subjecting the same therein to independently controlled cracking conditions of temperature and pressure, introducing the thus treated reflux condensate into the enlarged zone, and finally condensing the fractionated vapors.

6. A hydrocarbon oil conversion process which comprises heating the charging oil to distillation temperature and separating therefrom a relatively light fraction and a heavier fraction, heating the light fraction to cracking temperature in a heating zone and then discharging the same into an enlarged zone, separating vapors from residue in the enlarged zone, removing separated vapors from the enlarged zone and subjecting the same to fractionation, passing resultant reflux condensate through a second heating zone and subjecting the same therein to independently con trolled cracking conditions of temperature and pressure, introducing the thus treated reflux condensate into the enlarged zone, commingling residuefrom the enlarged zone with the heated reflux condensate passing from said second heating zone to the enlarged zone, and finally condensing the fractionated vapors.

7. A hydrocarbon oil conversion process which comprises heating the charging oil to distillation temperature and separating therefrom a relatively light fraction and a heavier fraction,

heating the light fraction to cracking temperature in a heating zoneand then discharging the.

same into an enlarged zone, introducing at least a portion of said heavier fraction of the charging oil into the enlarged zone, separating vapors from residue in the enlarged zone, removing separated vapors from the enlarged zone and subjecting the same to fractionation, passing resultant reflux condensate through a second heating zone and subjecting the same therein to independently con-- trolled cracking conditions of temperature and pressure, introducing the thus treated reflux condensate into the enlarged zone, commingling residue from the enlarged zone with the reflux condensate passing from said second heating zone to the enlarged zone, and finally condensing the fractionated vapors.

8. A process for the conversion of hydrocarbon oils which comprises heating a hydrocarbon oil charging stock and subjecting it to vaporization whereby its low-boiling fractions are vaporized and separated from its higher boiling nonvaporous fractions, subjecting said low-boiling vaporous fractions of the oil to conversion conditions within a heating coil and introducing the products into an enlarged chamber wherein the vaporous and non-vaporous residual conversion products separate, subjecting the vapors to fractionation whereby their ins ufliciently converted components are condensed as reflux condensate, subjecting fractionated vapors of the desired endboiling point to condensation, collecting the resulting products, subjecting the reflux condensate formed by said fractionation of the vapors to further conversion in a separate heating coil and introducing the heated products from said separate heating coil into said'enlarged chamber, and commingling with the stream of hot conversion products passing from the last-mentioned heating coil to said enlarged chamber a regulated portion of the residual liquid separated from the vaporous conversion products in said enlarged chamber.

9. The process as defined in claim 8 further characterized in that said portion of "*the, residual liquid is cooled prior to commingling withsaid stream of hot conversion products. I

10. A process for the conversion of hydrocarbon oils which comprises heating a hydrocarbon oil charging stock and subjecting itto vaporization whereby its low-boiling fractions are vaporized and separated from its higher boiling nonvaporous fractions, subjecting said low-boiling vaporous fractions of the oil to conversion conditions within a heating coil and introducing the products into anenlarged chamber'wherein the vaporous and non-vaporous residual conversion roducts separate, subjecting the vapors to fractionation whereby their insufficiently converted components are condensed as reflux condensate,

subjecting fractionated vapors of the desired endboiling point to condensation, collecting the resulting products, subjecting the reflux condensate formed by said fractionation of the vapors and said non-vaporous high-boiling fractions of the charging stock to conversion in a separate heating coil and introducing the heated productsfrom said separate heating coil into said enlarged chamber.

11. A process for the conversion of hydrocarbon oils which comprises heating a hydrocarbon oil charging stock and subjecting it to vaporization whereby its low-boiling fractions are vaporized and separated from its higher boiling nonvaporous fractions, subjecting said low-boiling vaporous fractions of the oil to conversion conditions within a heating coil, and introducing the products into an enlarged chamber wherein the vaporous and non-vaporous residual conversion products separate, commingling vaporous high-boiling fractions of the charging stock with the stream of hot conversion products passing from said coil to said enlarged chamber, subjecting the vapors to fractionation whereby their insufficiently converted components are JACOB BENJAMIN HEID.

said non-

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