US2000399A - Hydrocarbon oil conversion - Google Patents

Description

May 7, 1935.

c. w. LUToN ET Al.

HYDROCARBON OIL CONVERSION Filed Aug. 7, 1930 Patented May 7, 1.935

HYDROCARBON OIL CONVERSION Clarence W. Luton and John Beddow, Toledo, Ohio, assignors to Universal Oil. Products Company, Chicago, Ill., a corporation of South Dakota Application August 7,

2 Claims.

'I'his invention relates to the treatment of hydrocarbon oils, and refers more particularly to the conversion of higher boiling hydrocarbons into lower boiling hydrocarbons.

an improvement in a process for the treatment of hydrocarbon oils, comprising subjecting the hydrocarbon oils to heat treatment at a conversion temperature, discharging the heated hydrocarbons into an enlarged reaction zone, and

thereafter separating the vaporized and unvaporized materials for further treatment.

In a specific embodiment, the invention provides an improvement in a process for the treatment of hydrocarbon oils, which comprises introducing at definite levels in the reaction chamber reflux condensate from the process, or a similar oil of lower boiling characteristics than the unvaporized residue withdrawn from the reaction chamber. Examples of such lower boiling oils are: pressure distillate bottoms, kerosene distillate, light gas oils, etc. VThe reiiux condensate may be obtained from a primary or secondary fractionating device or both. Prefer- 25 ably, the reflux condensate or other lower beiling liquid is introduced at the interface or contact. surface between the unvaporized residue and the vapors in the reaction chamber. 'I'his interface, or the point just below it, is termed the black level because material withdrawn by means of try cock levels below the interface is black and opaque, indicating unvaporized liquid residue, whereas that withdrawn above is more' or less translucent, indicating that vapors have been withdrawn. As the level in the reaction chamber is changed, the point of introduction of the lighter oil is correspondingly changed.

Among the objects of the invention is to pro- 40 vide a process for lengthening the operating cycle, increasing the yield of gasoline, improving the quality of the' residuum, and eliminating operating difficulties, such as stoppage of residuum draw-off lines, and increasing the over-all flexibillty of operation.

This is accomplished by cutting down the reaction temperature within the liquid body in the manner hereinafter described, preventing the formation of coke and suspended carbonaceous 50 matter orpitchy material, which causes clogging of the draw-.olf lines. This permits a higher conversion temperature in the heating element, increasing not only the gasoline per pass but the over-al1 yield.

Other desirable features of the invention will In its general aspect, the invention providesv 1930, Serial N0. 473,547

(Cl. ISS-48) be more fully illustrated by reference to the accompanying drawing, which is diagrammatic and not to scale, and which represents one form of apparatus suitable for carrying out the process of the invention.

Raw oil charging stock is passed through line I, controlled by valve 2, and is pumped by means of pump 3 through line 4, controlled by valve 5, into the dephlegmator 6, where it is contacted and undergoes heat exchange with the ascending vapors, preheating the raw oi1 and causing a partial condensation of the heavier components ofthe vapors arising in the dephlegmator 6.

A portion or all of the raw oil may be passed through line 1, controlled by valve 8, and through line 9 into the heating element I0 locatedv in furnace setting I I. 'Ihe oil heated to its conversion temperature passes through the transfer line I2, controlled by valve I3, into the reaction chamber I4. The vapors leaving the reaction chamber I4 pass through line -I5, controlled by valve I6, into the dephlegmator 6. The reflux condensate from the dephlegmator 6, together with the raw oil, passes through line I1, controlled by valve I8, and is pumped by means of lpump I9 through line 20, controlled by valve 2| into the heating element I0. The vapors leaving the dephlegmator 6 pass through line 22, controlled by valve 23, into cooler and condenser 24. The liquid, together with gases, passes through line 25, controlled by valve 26, into the receiver 21. 'I'he liquid is withdrawn from receiver 21 through line 28, controlled by valve 29. The -gases are withdrawn through line 30, controlled by valve 3|. A portion of the liquid may be recirculated from the receiver 21 through valve 32 and line 33 by. means of pump 34, through 'line 35, controlled by valve 36, into dephlegmator 6, where it assists in cooling the vapors therein and regulating the boiling range of the distillate leaving the dephlegmator 6.

Unvaporized liquid residue from the reaction chamber I4 may be Withdrawn through one or several of lthe lines 31,38, 39, 40, controlled by valves 31', 38', 39', 40', through manifold line 4I, where it may be collectedand sent to storage or used for other purposes.

As'a feature of the invention, a portion of the reflux condensate 'passing through line 20, controlled by valve 2l, may be diverted through line 5I, valve 52 and cooler 53 and thence passed through line 42, controlled by valve 43, into one or several of lines 44, 45, 46, 41, controlled by valves 44?, 45', 46', 41', the particular line and 5 valve selected depending upon the level within the reaction chamber. A suitable oil, preferably lighter than the residuum withdrawn from the .reaction chamber, and more preferably of a distillate character, may be pumped by means of pump 48 through line 49, controlled by valve 49', and through line 50, controlled by valve 50 into line 42 and thence into reaction chamber I4 as already described. A y

As a speciiic .example of the results obtained by the operation of the process of the invention, when the residuum is not cooled and recirculated in the manner described, a yield of approximatelyv 44% gasoline is obtained, .producing at the same time a yield of approximately 44% residuum oi' an average A. P. I. gravity of 13, containing from 6% to 8% B. S. or suspended carbonaceous matter. The percentage of coke, gas and loss was approximately 5%. The amount of coke made was approximately 4 pounds per barrel of cracking stock.

The operating conditions during this run were In this operation, the transfer temperature was increased to approximately 925 F., without any diiilculty due to stoppage of the residuum drawoif lines. The pounds of coke per barrel of raw oil charged was reduced from approximately 4 pounds to approximately 2 pounds or less. The charging capacity per stream day was increased from approximately 2200 barrels to approximately 2400 barrels. The number of hours on stream was increased from approximately 200 to approximately 300. The coke deposited in the upper tubes of the heating element was reduced considerably by the'operation of our improved process.

The pressure on the reaction chamber in this run was maintained at approximately 185 pounds per square inch, with equalized pressures on the other elements of the system.

The following speciiic data further illustrates the results obtained in the operation of the process oi our invention:

Exam le No. 1 Example No. 2 Recircnlating erosene distillate Recirculating pressure distillate bottoms Percent Percent Change in change Change in chan e Former Improved results from (based on Former Improved results from on operation operation former operaproduct) operation operation former operaproduct) tion former tion former operation operation 225 280 +55 hrs +24. 5 225 340 121 hrs +53. 8 Toppe'l crude- Topped crude 24. 6 25.4 +0.8" A. P. I. 24. 6 25.8 +1. 2 A. P. I. 21, 244 27, 959 +6,7l5 bbls- +31. 0 21, 244 32, 614 11,370 bbls.. +53. 4 260 2, 389 +129 bblS----- +5. 7 2, 260 2, 5 bbls.- +0. 2

49. 9 52. 8 +2.9 o +5. 8 49. 9 53. 1 +32? +6. 4 55.7 53. 7 -2.0 A. P. I. 55. 7 54.4 -1.3 A. P. I--

45. 1 39. 3 5.8% -12. 8 45. 1 41. 0 4.1% 9. 1 13.9 13. 7 0.2 A. P. I 13.9 13. 5 *0.4 A. P. I..

40 18 40 4 3. 8 1. 3 -2.5#/bbl.---- -65. 8 3. 8 0. 3 3.5#/bbl..- -92. 1

9, 339 12, 654 9, 339 14, 761 based on pressure distillate.-- 88. 0 85. 6 -2.4%- 88. 0 85. 2 2.8% based on cracking stock- 43. 9 45. 2 +1.3ZJ +3. 0 43. 9 45. 2 +1.3% +3.0 Pressure distillate b0ttoms**- Total bbls 742 1,380 742 1, 690

o based on pressure distillate... 7. 0 9. 4 +2.4%. 7. 0 9. 8 +2.8% a based on cracking stock. 3. 4. 9 +1.4% +40. 0 3. 5 5. 1 +1.0% +45. 7 0 rating eondmonsistillate returned to chambera based on cracking stock. None 5. 4 None 4. 7 urnaoe temp. F. above tubes- 1550 1600 1550 1G10 Furnace temp. F. below tubes- 1095 1140 1095 1130 Temp. F. heating ooil mlet 765 765 765 765 Temp. F. heating coil outlet 900 925 900 925 Temp. F. vapors to dephlegmatcr 850 860 350 850 Preure reaction chamber lbs/sq. meh.- 185 185 185 185 Could have run tor about 25 days.

l 410 F. cut in 100 cc. Engler distillation. "Bottoms remaining in iiasl: after removal 0i 410 F. cut.

approximately 900 F. temperature, that is, the temperature of the oil leaving the heating element, 850 F. temperature of vapors to the. dephlegmator, 475 F. temperature of vapors to the condenser, maintaining a pressure of 180 pounds per square inch throughout the system. The

capacity in barrels of cracking stock per stream day in this operation was approximately 2200.

When recirculating approximately 5% pressure distillate bottoms based on the charging stock, or other similar distillates such as kerosene distillate, we have been able to increase the gasoline yield to approximately 48%, and while the residuum percentage was decreased to approximately 39%, its B. S. content was reduced from approximately 8% to approximately 0.6%.

The charging stock utilized in both cases was a 24-25 A. P. I. gravity topped Mid-Continent crude.

The above examples will serve to illustrate the advantages of our" invention, but inasmuch as they are illustrative they should not be construed as limitations upon the broad scope of our invention.

We claim as our invention:

1. A hydrocarbon oil cracking process which comprises passing the oil in a restricted stream through a heating zone and heating the same therein to cracking temperature under pressure, discharging the heated oil into a vapor separat-A ing zone above the liquid level therein and separating thefsame therein into vapors and unvaporized oil, maintaining the latter zone under cracking conditions 0I temperature and pressure, introducing into said separating zone adjacent the contact surface between vapors and unvaporize'd oil therein a relatively cool oil of lower boiling point than said unvapcrized oil, said re1- ativelv cool oil being introduced at a temperature and in amount such as will substantially reduce coke and sludge formation in the unvaporized oil, and during the operation o! the process varying the point of introduction of said relatively cool oil to the separating zone in accordance with variations in the liquid level of unvaporized oil therein.

2. A hydrocarbon oil cracking process which comprises passing the oil in a restricted stream through a heating zone and heating the same therein to cracking temperature under pressure, discharging the heated oil into a vapor separating zone above the liquid level therein and separating the same therein into vapors and unvaporized oil, passing the separated vapors to a dephlegmating zone and condensing insuiliciently cracked fractions therein as reux condensate, passing a portion of the reflux condensate through a cooling zone and thence into said separating zone, introducing the thus cooled portion oi.' the reilux condensate into the separating zone adjacent the contact surface between vapor and unvaporized oil therein in amount sumcient to substantially reduce coke and sludge formation in the unvaporized oil, passing another portion of the reux condensate from the dephlegmating zone directly to the heating zone without appreciable cooling thereof. and condensing the dephlegmated vapors as a product of the process.

CLARENCE W.'LUTON. JOHN BEDDOW.

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