US1867823A - Process of forming coke from mineral hydrocarbons - Google Patents

Description

y 1932- R. A. HALLORAN ET AL 1,867,823

PROCESS OF FORMING COKE FROM MINERAL HYDROCARBONS Filed June 1, 1927 gwuz'nfow W X02 M 1.6 w v Av Patented July 19, 1932 UNITED STATES PATENT OFFICE RALPH A. HALLORAN AND 'WILIJAM H. SHIFFLER, OF BERKELEY, CALIFORNIA, AS- SIGN OBS TO STANDARD OILv COMPANY OF CALIFORNIA, OF SAN FRANCISCO, CALI- FORNIA, A CORPORATION .OF DELAWARE PROCESS OF FORMING COKE FROM MINERAL HYIDBOCABBONS Application filed June 1, 1927. Serial No. 195,648.

treatment of mineral hydrocarbons for the production of coke and recovering other valuable constituents from said residua.

lVhen petroleum oils are subjected to the action of metallic halides at elevated temperatures there is formed a heavy tarry residuum which on standing separates out from the oil. This follows whether the treatment with the halide is for the purpose of purifying the oil or, converting it wholly or in part to lower boiling point hydrocarbons. The residuum will contain substantially all of the metal and halogen which were originally added to the oil. It is, therefore, desirable to recover from such residua as much as possible of these valuable constituents, and many processes have been proposed with this end in view. For example residuum may be subjected to high temperatures, as in acoke oven, whereby metallic halide, hydrocarbons and halogen acid gas are expelled,

leaving behind a dense, hard coke. Another recovery method consists in leaching the residuum with water (or steam) to separate the metal and halogen from the tarry or cokey mass.

It is to be noted that the residuum formed in the oil treatment varies in character with the progress of the refition: In the early stages the residuum is of the nature of a thin liquid. As the reaction progresses it becomes heavier and more viscous. At length, by degrees, it becomes semisolid and finally definitely solid and granular. In other Words, the melting point of the residuum rises progressively. In these later stages the reactive or catalytic property of the treating material diminishes and finally, if the treatment is continued long enough, practically ceases. F or a given oil, such as gas oil derived from California crude oil, and a given treating agent, such as anhydrous aluminum chloride, the rise in melting point of the residual material may be said to proceed more or less rapidly according to the temperature used in the treatment. The reaction proceeds at a more rapid rate at a high than at a low temperature. In a continuous process the melting point of the residuum depends upon the temperature of the system and the length of time the halide has been in contact with the oil in passing through the system, other things being equal. If the residuum is allowed to solidify in the treating apparatus'it is difiicult to remove, particularly without openingthe apparatus. In the event that the apparatus is opened for cleaning there is not only a great loss of time, but also there is a tendency toward accumulation of moisture in the apparatus which even in small amount aids in the formation of corrosive compounds during subsequent operations. If the residuum is removed from the treating apparatus as a liquid and allowed to cool and solidify it is extremely ditficult and expensive to re-melt it, for the reason that the application of external heat to the container forms a layer of hard coke practically impervious to heat.

It is an object of the present invention to provide a process of treating mineral hydrocarbons with aluminum chloride in which the residuum formed can be removed from the treating apparatus in liquid state and while in said liquid state passed into an oven and therein decomposed into coke with the liberation and recovery of other valuable products. By the process of the present invention an accumulation of moisture in the treating apparatus is prevented and the residuum is introduced into the coking or decomposing oven at the temperature of the cracking reaction and without the necessity and expense involved in cooling the residuum, breaking the same up and charging the same in solid form into the oven.

In accordance with the present process the residuum from the metallic halide treatment of hydrocarbon oil whether it be that derived from shale, coal, petroleum or other sources, is withdrawn from the treating apparatus while still in a liquid state and maintained in the liquid state until it is discharged into a chamber, oven or retort for carrying out the recovery and coking operation. For example, the residuum to be coked or subjected to a process for recovering various valuable constituents thereof may be conveyed from the cracking apparatus through a well insulated pipe directly into the coking oven or into a storage bin wherein it is kept heated to maintain the same in liquid state so that it may be at any desired time charged into the coking oven. Where the oil treatment is carried out under a pressure above atmospheric, this transfer of the residuum may be efi'ectel solely by the still pressure. In other cases it may be pumped through the insulated line.

The process of the present invention will best be understood from a description of a preferred form, for example, of a process embodying the invention as carried out in a preferred form of apparatus. Reference is therefore made to the apparatus illustrated in the accompanying drawing. 4

In the drawing the figure represents a diagrammatic elevation partially in vertical section of a suitable treating apparatus.

Referring to the drawing 2 indicates a reaction chamber or still in which a reaction between mineral hydrocarbons and anhydrous aluminum chloride may be conducted. The still 2 as indicated is heated in any suitable manner such as mounted overa furn ace 8 provided with a burner 4. The still 2' is also preferably provided with a pipe line 5 leading to a condenser 6 and thence to a suitable vessel 7 through which the vaporized products from the still may be passed, condensed and collected.

The still 2 is preferably provided with an insulated draw-o5 conduit 8 which preferably leads to an insulated blow case 9. The blow case 9 is provided in order that a regulation of the transfer of the residuum may be effected. By means of the blow case 9 measured quantities of residuum may be with drawn from the still 2. Moreover bythe use of the blow case 9 additional pressure may be applied for transfem'ing the residuum to the coking apparatus and a means for cleaning out the transfer line is obtained. The blow case 9 is indicated as provided with a line 10 through which gas under pressure may be admitted to the case for imposing additional pressure thereon for forcing the residuum to the coking apparatus. 11 indicates the discharge conduit from the blow case 9 which is preferably well insulated in order that the residuum will not solidify therein. The con duit 11 may lead directly to the retort 12 of a coking oven 13, but is indicated as preferably passing to a storage vessel 14 located above the retort 12. The storage vessel 14 is preferably provided with a coil 15 or other suitable means by which the residuum may be maintained liquid within the vessel 14 until it is charged into the retort 12. 16 indicates a pipe line for discharging gas from the torage vessel let. I

Any preferred or customary form of coking oven may be employed. There is indicated,-

however, a coking oven in which the retort 12 is of the'vertical type and adapted to be surrounded by flue gases from a burner 17 The retort 12 is indicated as provided with a pipe line 18 through which may be discharged the aluminum chloride, -hydrogen chloride, hydrocarbon gases or other products driven from the residuum in the coking operation. Said line may lead to any suitable apparatus for recovering such valuable constituents.

The process as carried out in the apparatus thus described is preferably as follows: Mineral hydrocarbons such as the gas oil fraction of California crude oil is contacted withanhydrous aluminum chloride in any desired proportion within the reaction chamber 2 at a temperature suitable for cracking the mineral hydrocarbons with the production of low-boiling-poiut hydrocarbons. Such lowboiling-point hydrocarbons pass out of line 5 and are condensed in condenser 6 and collected in Vessel 7. The temperature of the reaction generally ranges from 500 to 700 I and is usually around 600 F. A stirrer 19 is indicated within the reaction chamber 2 for agitating the contents during this treatment. Preferably the treatment is continued for such a period of time. usually about six hours, that the residuum becomes comparatively heavy and viscous so that it is in condition to be very readily coked.

After the residuum has been reduced to such condition it is withdrawn from line 8 into blow case 9 from which it is transferred through line 11 while still in liquid state into the vessel 14;. In vessel 14: the residuum is maintained in liquid state preferably by hot oil or gases passing through coil 15 until it is ready to be charged into the retort 12.

Before introducing the residuum into the retort 12 the retort 12 is preferably heated to a temperature suitable for reducing the re.- siduum to a coke, such temperature being indicated for example by a pyrometer (not shown) located in the center of the retort 12. A suitable coking temperature is around 1800 F.

The residuum from vessel 14 upon being introduced into the coking chamber 12 is decomposed or carbonized leaving a coke consisting essentially of carbon and alumina. In this coking operation the residuum decomposes into aluminum chloride. hydrogen chlo ride and hydrocarbon gases which pass out of the retort through pipe line 18 and such gases may be processed in any usual or preferred manner for the recovery of their valuable constituents.

By the process of the present invention the difficulty of charging the retort 12 with the oil residuum to be coked and the difficulty of remelting the residuum is eliminated. The

transportation of the residuum is accomlished easily and quickly with a minimum cost and delay. Moreover the residuum does not come into contact with atmospheric moisture thereby reducing the amount of alumina and ash forming ingredients which are found in the coke produced in retort 12. When the residuum is permitted to absorb moisture such moisture operates to decompose aluminum chloride present in the residuum which would otherwise pass off as aluminum chloride and forms therefrom hydrogen chloride and alumina. The alumina thus formed increases the percentage of alumina and ash in the ultimate coke produced.

While the process as herein described is well adapted to carry out the object of the present invention, it is understood that various modifications and changes may be made without departing from the invention and the present invention includes all such modifications and changes as come within the scope of the following appended claims.

We claim:

1. A process of making coke from the hot residuum of the process of treating mineral oil with anhydrous aluminum chloride for the production of lower boiling hydrocarbons from higher boiling hydrocarbons in a reaction zone, which comprises, withdrawing the residuum from said reaction zone shortly before the period at which the residuum would solidify, passing the residuum into a coking zone while still in a hot liquid state, the coking zone being preheated to a coking temperature before the introduction of the residuum, and holding the residuum in the coking zone at a high temperature sufficient to decompose the same into coke while deriving such chloride compounds therefrom.

2. A process of making coke from the hot residuum of the process of treating mineral oil with anhydrous aluminum chloride for the production of lower boiling hydrocarbons from higher boiling hydrocarbons in a reaction zone which comprises withdrawing the residuum from said reaction zone shortly before the period at which said residuum would solidify, passing the residuum into a coking zone while still in the hot liquid state, the coking zone being preheated to a coking temperature before tlga introduction of the residuum, and holding the residuum in the coking zone at a temperature of about 1800 F. until the sameis decomposed into a coke while deriv ing such cloride compounds therefrom.

Signed at San Francisco, this 17th day of May, 1927.

RALPH A. HALLORAN. WILLIAM H. SHIFFLER.

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