US1945604A - Hydrocarbon oil conversion - Google Patents

Description

1934- ,D. F. GERSTENBERGER 1,945,604

HYDROCARBON OIL CONVERSION Filed April 4, 1932 INVENTOR DONALD F. GERSTENBERGER BY 7 fl ATT NEY KMZMUUE Patented Feb. 6, 1934 f 1,945,604

----.--------UNITED STATES PATENT OFFICE HYDROCARBON 01L CONVERSION Donald F. Gerstenberger, Chicago, Ill.', assignor to Universal Oil Products Company, Chicago, 111., a corporation of South Dakota Application April 4, 1932. SerialNo. 602,904

\3 Claims. (01. 196-60) This invention relates to the conversion of hypreferably so proportioned to give substantially drocarbon oil, and more particularly refers to the same total vapor time that would be obtained improvements in the type of cracking process in the ordinary type of single vapor-phase reacand apparatus wherein the hydrocarbon oilissubtion chamber but giving an increased vapor vejectedto conversionconditions of elevated temlocity. High vapor velocity alone has been 60 perature and substantial superatmospheric presknown to decrease the deposition of coke and, sure in a heating element, followed by 0011- as here used, in combination with the quick retinued conversion, at superatmospheric pressure, moval of coke-forming residual liquids at various particularly of the vaporous materials resulting. stages during the treatment, will, under the propfrom the heat treatment, quick separation of er temperature and pressure conditions for the 65 residual liquid from the vapors and further vaparticular oil being treated, substantially elimporization of the latter at reduced pressure. inate coke deposition in the reaction zone and in The improvements of the present invention many cases will even permit the use of an inare particularly concerned with the'quick separacreased conversion temperature without increastion from the vapors and removal from the reing the coke and gas formation, thereby material 70 action zone of residual liquid conversion prodly improving the anti-knock value of the finished ucts during the conversion time in the reaction motor fuel product of the system. zone following the heating element and com- The attached diagrammatic drawing illusprise methods and means of removing said residtrates one specific form of apparatus incorporat ual liquid products at various stages during this ing the features of the present invention and in 75 continued conversion time instead of removing which the process of the invention may be sucthe total residual liquid products together with cessfully practiced. Raw oilcharging stock may the vapors from the reaction zone. In this manbe supplied through line 1 and valve 2 to pump ner the residual liquid issubjected to much short- 3 from which it may be fed through line 4 and er conversion time than the vapors. The advanvalve 5 to heating element 6. When desired, a 80 tages of short liquid conversion time and proportion or all of the raw oil may pass from pump longed vapor conversion time are sufliciently well 3 through line 7 and valve 8 into fractionator known to require no explanation or justification 9 wherein it comes into direct and counterhere. current contact with the cracked vapors, serving One specific manner in which the advantages to partially cool the latter and assist their fracas of the concepts of the present invention may be tionation and being thereby preheated. The obtained comprises utilizing a plurality of elonrelatively heavy components .of the vapors are gated vertical reaction chambers connectedinsecondensed in the fractionator and collect, tories,heated conversion products from the heating gether with the preheated raw oil, in the lower element of the system entering the upper porportion thereof, from which they are withdrawn tion of the first reaction chamber, vapors from through line 10 and valve 11 to pump 12. The the lower portion of each chamber passing to the reflux condensate or reflux condensate and preupper portion of the succeeding chamber and reheated raw oil from factionator 9 is directed sidual liquid being withdrawn from the lower from pump 12 through line 13 and valve 14 into 40 portion of each chamber. In the last chamber line 4, commingling therein with the raw oil, of the series the residual liquid formed in this or that portion, if any, supplied directly to line zone may be withdrawn therefrom separately or 4 from pump 3, and passing therewith to heating together with the final vaporous product from element 6. g g the entire series and, in the preferred embodi- Heating element 6 is located in a furnace 15 of 45 ment of the invention, both vaporous and liquid any desired form suitable for supplying the reproducts from the reaction zone are discharged quired heat to the oil undergoing conversion. into a reduced pressure vaporizing chamber al- The heated oil is discharged from heating elethough, when desired, the vaporous products may ment 6 through line 16 and valve 17. into the pass from the reaction zone directly to fractionaupper portion of reaction chamber 18.

50 tion while the residual liquids removed from Chambers 18, 19'and 20 are similar reaction each reaction chamber are commingled and subzones wherein conversion of the vaporous prodjected to further vaporization at reduced presucts may continue for a predeterminedtime while sure. In the arrangement above described, any the residual liquid products are removed therenumber of a plurality of reaction chambers may from without being subjected to extensive further 55 be employed, their diameter and height being conversion time. Products from heating element 6 pass downward through chamber 18, The unvaporized liquid which enters this zone and the residual liquid formed during passage of the materials through this chamber are withdrawn from its lower portion through line 21 and valve 22. vaporous products separately withdrawn from chamber 18 pass through line 23 into the upper portion of chamber 19, passing downward through this zone. The residualliquid formed in chamber 19 is withdrawn from its lower portion through line 24 and valve 25 while the vaporous products are separately withdrawn through line 26 and enter the upper portion of chamber 20, passing downward therethrough. The residual liquid formed in chamber 20 is withdrawn from its lower portion through line 27 and valve 28. The vapors from chamber 20, which comprise the total conversion products remaining in vaporous form at this state of the process, may be handled in any one or any combination of several manners. They may be separately withdrawn from the lower portion of chamber 20 through line 29 and may pass through line 30 and valve 31 directly to fractionator 9, or they may be directed, all or in part, through valve 32, in line 29, into line 33 and thence to reduced pressure vaporizing chamber 35 or, when desired, all or any portion of the vapors may be withdrawn from chamber 20, together with the residual liquid formedin this zone, through line 27 and valve 28. The residual liquids from each of the chambers are commingled in line 33- and pass through valve 34 into reduced pressure vaporizing chamber 35. In case all or any portion of the vapors from chamber 20 pass eitherthrough line 27 and valve 28 or through line 29 and valve 32 into line 33, they commingle therein with the residual liquid products and pass therewith to chamber 35, serving to further heat these products and assist their vaporization at reduced pressure.

Residual liquid remaining unvaporized in chamber 35 may be withdrawn therefrom through line 36 and valve 37 to cooling and storage or to any desired further treatment. Vapors from chamber 35 pass through line 38 and valve 39 into fractionator 9 which, in the case illustrated, is the same fractionator to which vaporous products from chamber 20 are directed, in case they are not first commingled with the residual liquid.

The heavy components of the vapors supplied to fractionator 9 are condensed by fractionation in this zone, passing therefrom, as already described, to heating element 6 for further conversion. The light components of the vapors re- -maining uncondensed within the fractionator are withdrawn from the upper portion thereof through line 40 and valve 41, are subjected to condensation and cooling in condenser 42, distillate and uncondensable gas from which are directed through line 43 and valve 44 to collection in receiver 45. Uncondensable gas may be released from receiver 45 through line 46 and valve 4'7. Distillate may be withdrawn from the tially reduced pressure of the order of 100 pounds down to substantially atmospheric may be employed in the vaporizing chamber and the pressure in the succeeding fractionating, condensing and collecting portions of the cracking system may be substantially equalized therewith. The conversion temperature employed at the outlet from the heating element may range, for example, from 850 to 1,000 F.

The following examples of specific operating conditions and results obtainable by their use are given for the purpose of more clearly illustrating the features and advantages of the presentvinvention. Let'us first consider a cracking operation such as that above illustrated and described except that only one high pressure reaction chamber is employed, products from the heating element entering its upper portion'while both vaporous and liquid products are simultaneously withdrawn from the lower portion of the chamber and directed to the reduced pressure vaporizing chamber. The rawoil charging stock supplied to this system is a blend of Pennsylvania naphtha and fuel oil having a gravity of approximately 43 A. P. I. A temperature of about 925 F. is employed at the outlet from the heating element and a pressure of about 350 pounds is utilized in the heating element and reaction chamber. The pressure in the vaporizing chamber is reduced to approximately 50 pounds per square inch. This operation may yield, per barrel of charging stock, about of motor fuel having an octane number of approximately 73 and about 6% of heavy residual oil having a gravity of about 4 A. P. I. The gas production is less than 400 cubic feet per barrel of charging stock, but the total coke, gas and loss is approximately 14% In another operation utilizing the same charging' stock and the same type of operation, with the exception that the features of the present invention are utilized by employing three reaction chambers such as illustrated and above described; the reaction chambers are substantially the same length as the single reaction chamber utilized in the above operation and the cross-sectional area of each is approximately one-third of that of the single reaction chamber, thus giving substantially the same vapor reaction time and about three times the vapor velocity through the reaction zone. In this operation the temperature of the oil leaving the heating element is increased to approximately 935 F. The yield of gasoline recovered by this operation is substantially the same (approximately 80% of the charging stock) and its anti-knock value is increased to an octane number of approximately 78. About 10% of residual oil of improved quality may be recovered and the production of gas is slightly increased but, owing to the decreased formation of coke in the reaction zone and the negligible deposition of this material in the reaction chambers, the operating time is greatlyprolonged over that possible in the first operation described.

I claim as my invention:

1. A hydrocarbon ofl cracking process which comprises heating the oil to cracking temperature under pressure while flowing in a restricted stream through a heating zone, discha ging the heated oil into the upper portion of an unheated vertically elongated reaction zone maintained under cracking conditions of temperature and pressure, passing the vapors and unvaporized oil downwardly through the reaction zone and separately removing the vapors and unvaporized oil from the lower portion of the reaction zone, in- 1 troducing the vapors to the upper portion of a second vertically elongated reaction zone maintained under cracking conditions of temperature and pressure, passing the vapors downwardly through the second reaction zone and removing the same from the lower portion thereof, passing the unvaporized oil withdrawn from the first-mentioned reaction zone and such liquid constituents as are formed in the second reaction zone to a vaporizing zone maintained under lower pressure than the reaction zones and distilling the same therein, supplying the vapors evolved in the vaporizing zone and the vapors withdrawn from the second reaction zone toa common fractionating zone and fractionating the admixed vapors therein, retuming resultant reflux condensate to the heating zone for recycling through the process, and finally condensing the fractionated vapors.

2. A hydrocarbon oil cracking process which comprises heating the oil to cracking temperature under pressure while flowing in a restricted stream through a heating zone, discharging the heated oil into the upper portion of an unheated vertically elongated reaction zone maintained under crack ing conditions of temperature and pressure, passing the vapors and unvaporized oil downwardly through the reaction zone and separately removing the vapors and unvaporized oil from the lower portion of the reaction zone, introducing the vapors to the upper portion of a second vertically elongated reaction zone maintained under cracking conditions of temperature and pressure, passing the vapors downwardly through the second reaction zone and removing the same from the lower portion thereof, subsequently combining the vapors with the unvaporized oil withdrawn from the first-mentioned reaction zone and introducing into vapors and residue in the vaporizing zone,

fractionating the last-mentioned vapors to condense heavier fractions thereof and returning resultant reflux condensate to the heating zone,

and flnally condensing the fractionated vapors.

3. In a hydrocarbon oil cracking process of the character wherein the oil is heated to cracking temperature under pressure while flowing in a restricted stream through a heating zone, the vaporous and liquid oil thence passed downwardly through an unheated vertically elongated reaction zone, the liquid oil withdrawn from the lower portion of the reaction zone and flash distilled in a vaporizing zone by pressure reduction; the improvement which comprises separately removing vapors from the lower portion of the reaction zone and passing the same through a series of vertical vapor reaction zones maintained under cracking conditions of temperature and pressure, introducing the vapors to the upper portion of each of the vapor reaction zones to flow downwardly therethrough and removing the vapors from'the lower portion of each of the vapor reaction zones, introducing liquid constituents formed in the vapor reaction zones to said vaporizing zone, combining the vapors withdrawn from the last vapor reaction zone of the series with the vapors evolved in the vaporizing zone, fractionating the vapor mixture Lto condense heavier fractions thereof and returning resultant reflux condensate to the heating zone, and finally condensing the fractionated vapors.

DONALD F. GERSTENBERGER.

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