US1938817A - Process of cracking hydrocarbon oil - Google Patents

Description

Dec. 12, 1933. G. EGLOFF PROCESS OF GRACKING HYDROCARBON OIL .Filed March 22. 195o Patented Dec. 12, 1933 UNITED STATES PROCESS 0F CRACKIWG HYDROCARBON Gustav Eglo, Chicago, Ill., assignor to Universalr Oil Products Company, Chi

ration of South Dakota cago, Ill., a corpo- Application March 22, 1930. Serial No. 437,976

ZCIaims.

This invention relates to a process of cracking hydrocarbon oil and refers in its specic embodiment to a cracking process where zinc chloride is used to assist in the production of a stable refined motor fuel product.

It is among the objects of my invention to bring about the desulphurization of vthe cracked hydrocarbon product so that subsequent refining for s ulphur reduction and sweetening together with the expense and losses involved are reduced to a minimum or are entirely eliminated. De-

sulphurization brings about a reduction or minimizing of corrosion in the plant equipment and in the automotive equipment where the mot-or fuel of lowered sulphur content is consumed.

The practice of my invention in addition to producing'a hydrocarbon product of good color and low gum content brings about the stabilization of this product so that it will not readily go off color. 'Ihe formation of color in gasolines is not only undesirable from a marketing viewpoint, since a colorless gasoline can be more readily dispensed than a yellowish gasoline when using visible bowls, but is usually also an index of the formation of gum-like, 'polymerized material which affect the operation of the motor as is evidenced by the clogging of feed lines, interference with the proper operation of the carburetor and the sticking ofthe valves -in the motor. l

The anti-knock property of a motor fuelpisone of its most. important and valuable characteristics. The higher the anti-knock value or knock rating of a motor fuel, the greater is its efllciency. A change in this value during storage' is, therefore, a disturbing factor since a desirable motor may change to such an extent that it will require some form of treatment to restore it to its original market value. The addition' of antiknock materials, the use of inhibiting agents, blending with exceptionally high anti-knock motor fuel stocks, or repetition of previous treatment are methods used to prevent reduction of anti-knock value of motor fuel while in storage or to restore the anti-knock value if ithas fallen off. The use of my process minimizes or eliminates the use of these preventative and restoration methods and eliminates all of the uncertainties involved.

In thepractice of my invention, I use zinc chloride to promote the results that I have referred to above, I may use the-zinc chloride in solid form, finely divided and distributed in the oil introduced into the cracking process, or I may'use an aqueous solution of the zinc chloride,l

(Cl. ISG-54) introducing same at suitable points in the process. I may inject a solution of zinc chloride into the oil passing to the heating zone of the cracking process where it mixes thoroughly with the oil processed, and due to the vaporization of the water solvent, the zinc chloride remains in contact with the oil in lthe finely divided and intimately mixed condition. The zinc chloride present during the conversion exerts a desulphurization reaction and is also believed to cata-l e5 lyze the conversion reaction. When cracking some oils such as, for example those of Mexican origin having a high sulphur content, it may also be desirable to inject zinc chloride into the zone where the partially converted hydrocarbons 7o are separated from the lower boiling reaction products, and/or it may be desirable to treat the lower boiling products after separation from the partially converted products. In some cases the addition of the zinc chloride to the raw oil being introduced to the process causes a desulphurization reaction before the sulphur compounds, either present or formed in the process, have an opportunity to cause a corrosive action. In the practice of my invention, it is thus possible, depending upon the nature of 'the cracking stock and the manner in which itis to be cracked, to use the zinc chloride to obtain the desired results at various stages of the process.

Where temperaturesv prevail at which zinc chloride may separate out from the vapors and solidify, thereby causing stoppage in the system, provisions for admitting water or steam are used or other suitable means for continuously removing the zinc chloride are provided.

In carrying out myprocess, I do not wish to limit myself to the apparatus in which it is used since the invention can very well be carried out in connection with or as a step in the modern cracking process comprising heating and reaction zones with provisions for returning partially converted products for retreatment, together with condensing, cooling, and collecting. means. In some cases, the beneficial results of my process can be obtained in separate equip- 100 ment which may only involve vaporizing, processing, condensing, cooling and collecting means. The preferred embodiment of the process, however, is carried out in the cracking process as will be hereinafter described. f'

The attached drawing, which is a diagrammatic illustration, not drawn to scale, of one of the many suitable forms of apparatus to which my process is applicable, is shown and described to more clearly illustrate my invention. 110

Referring to the drawing, raw oil supplied through line 1 and valve 2 to pump 3 may be fed through line4 and valve 5 into dephlegmator 6 where it may be preheated by ascending vapors and may pass together with reflux condensate from dephlegmator 6 through line 7 and valve 8 to pump 9, and may be thence fed through line 10, valve 11 and line 12 into heating element 13. A portion or all of the raw oil instead of passing overhead to dephlegmator 6 may pass through line 14 and valve 15 into line 10, there mixing with reflux condensate being fed into heating element 13.

Zinc chloride in solution with water, alcohol or any other suitable solvent, or in suspension in oil, may be introduced into the charging stock before it enters heating element 13, being supplied through line 16 and valve 17 to pump 18 and thence fed into line 12.

Heating element 13 is located in any suitable form of furnace setting 19, and the oil passing therethrough is heated to the desired temperature under the desired pressure conditions and may be discharged through line 20 and valve 21 into reaction chamber 22 from which unvaporized products may be removed through line 23 controlled by valve 24, and 'vapors may pass through line 25 and valve 26 into dephlegmator 6.

Zinc chloride in'solution with water, alcohol or any other suitable solvent, or in suspension in oil, may be introduced into fractionating tower 6, being supplied to pump 29 through line 27 and valve 28 and thence fed into dephlegmator 6 through line 30 and valve 31.

Vapors from dephlegmator 6 may pass through line 32 and valve 33 into condenser 34. A portion of the zinc chloride introduced into dephlegmator 6 may be carried over with the vapors in line 32 and Water supplied through line 35 andvalve 36 to pump 37 may be fed through line 38 and valve 39 into the vapors and zinc chloride in line 32 to dissolve the zinc chloride and facilitate its action upon the vapors and the resulting condensate.

Vapors passing through condenser 34 may be subjected to condensation and cooling, the products passing therefrom through line 40 and valve 41 into receiver 42, uncondensed gas from which may be withdrawn through line 43 controlled by valve 44. The distillate collected in receiver 42 may be removed throughline 45 and valve 46. The zinc chloride solution collecting in receiver i2 may be withdrawn through line 47 and valve An equalized pressure varying from sub-atmospheric to high super-atmospheric pressures oi' say 2000 pounds per square inch, more or l'ess, may be utilized throughout the system, or differential pressures may be employed between the various parts of the apparatus. Conversion temperatures ranging from approximately 700 F. to 1200" F., more or less, may be utilized.

As a specific example of one embodiment of the practice of my invention and the' results obtained, a 32 A. P. I. gravityCalifornia gas oil containing 1.45% sulphur is charged to the dephlegmator 6 where it mixes with the vapors from the reaction chamber and serves to condense the 'partially converted hydrocarbons, the mixture being removed from the bottom of the dephlegmator and pumped to the heating coil 13. A concentrated aqueous solution of zinc chloride amounting to approximately 2% by Weight of the raw oil charged to the process is injected by the pump 18. The oil leaving the heating coll has a temperature of approximately 900 F. and

a pressure of approximately 250 pounds. Nonvaporized residuum oil amounting to 30% of the gas oil charged is withdrawn from the bottom of the reaction chamber 22. The temperature at the top of the dephlegmator 6 is approximately 525 F. The oil distillate removed from the receiver 42 has an A. P. I. gravity of approximately 50 and contains 'approximately' 83% motor fuel, having Aan end point of 412 F. The motor fuel is re-run without acid treatment and the finished motor fuel is stable and water white, having a sulphur content of approximately .14%. The non-vaporized residue removed from the reaction chamber is a marketable fuel oil.

I claim as my invention:

1. A process which comprises subjecting hydrocarbon oil to cracking conditions of temperature and pressure in a cracking zone, removing the vapors and dephlegmating the same at a temperature above the boiling point of water in contact with an aqueous zinc chloride solution, thereby evaporating water from the solution and forming reflux condensate containing suspended zinc chloride, supplying the reflux condensate to the cracking zone whereby the oil is cracked therein in the presence of zinc chloride, and finally condensing the dephlegmated vapors.

2. A process which comprises subjecting hydrocarbon oil to cracking conditions of temperature and pressure in a cracking zone, removing the vapors and dephlegmating the same at a temperature above the boiling point of water in contact with an aqueous zinc chloride solution, -thereby evaporating water from the solution and forming reflux condensate containing suspended zinc chloride, supplying the reflux condensate to the cracking zone whereby the oil is cracked therein in the presence ,of zinc chloride, adding water in liquid condition to the dep'hlegmated vapors and finally 4condensing the latter in the presenceof the water. Y

f V GUSTAV EGLOFF.

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