US2044416A - Method of coking hydrocarbon liquids - Google Patents

Description

Patented June 16, i936 Matta BIETHOD F COKING HYDOCARBON LIQUIDS Harold V. Atwell, White Plains, N. Y., assgnor to Gasoline Products Company, Inc., Newark, N. J., a corporation of Delawarel Application March 29, 1933, Serial No. 663,290`

1 Claim. (Cl. 202-36) h My invention relates to coking liquid or liqueable hydrocarbon material, such, for example, as residuums or tars derived from the distillation or cracking of petroleum oil, and other hydrocarbon liquids of petroleum and non-petroleum origin, such as crude or partially distilled petroleum, coal tar, coal tar pitch and analogous hydrocarbon materials, and an object of my invention is to provide a method whereby material of the character recited may be coked in a Suitable vessel, and whereby the resultant coke` may be removed from the vessel in which it is produced more readily than has been true ofl the method and apparatus applied in the prior art.

My invention has for further objects such additional operative advantages and improvements as. may hereinafter be found to obtain. In coking liquid or liqueiiable hydrocarbon material in the past it has frequently been found to be diflicult to remove the coke from the vessel in which the coking takes place. The material to be cokedusually passes through a state of high fluidity just prior to the time at which solidiiication or coking takesy place, and tends to adhere strongly to or to penetrate into. the walls of the coking vessel, depending upon'the nature of the material of which the vessel is contructed. While removal of petroleum coke or pitch coke from a coking chamber or vessel may be facilitated by carrying out the coking operation at a very high temperature, for example, 1600 F. or higher and subsequently calcining the coke at that temperature for a period usually amounting to several hours, in many instances this is either undesirable or impracticable. Such tional apparatus of an expensive character, such A Y as by-product coke-ovens or the like.

Removal of coke hasbeen a problem in the oil-cracking' art, in those instances at leastin which a dei'lnite coking operation is conducted in conjunction with or rather as a part of a cracking operation, due to the fact that the temperature of the coking operation is ordinarily limited v My invention contemplates providing interior surfaces of va vessel in which it is desired to effect the coking of a hydrocarbon liquid with a coating of substantial thickness of a material which is more or less friable at the temperature at 5 -which the coking takes place or which may be made relatively friable With respect to the coked mass after the coking operation has been com-- pleted, and having a surface which is substanf tially impervious with respect to the hydrocarbon liquid being coked.

The coating thus provided effectively separates the coked mass from the interior walls of the coking vessel, thus preventing the c oke or the material being coked`from adhering to or penetrating the walls of the coking vessel. The impervious surface of the coating or lining prevents the material being coked from penetrating into or through the coating or lining, at least to any material extent, so that at the completion of the coking operation there remains between the coke and the inner wall of the coking vessel a layer of material which as will be explained more fully hereinbelow is either relatively friable with respect to the coke or may be easily made so. When a force is applied to the mass of coke in a suitable manner, a disintegration or breaking down of the relatively friable lining takes place and the mass of coke comes out ofthe coking vessell or chamber easily and without serious destruction.

As mentioned hereinabove, my invention contemplates a lining or coating of substantial thickness, by which is meant a thickness ofsuiiicient `magnitude to permit a shearing or disintegratling of the coating material for the purpose of eiecting removal of coke. Thus the thickness ot thecoating may be,for example, 1A inch, or under occasional circumstances might even be somewhat less, although ordinarily coatings of l/ inch thickness or more are preferred.

My coating is thus sharply distinguished from mere protective coating or glazes applied to the walls of vessels intended for the treatment of hydrocarbon liquids and other materials, in which the purpose is merely to protect the material of the vessel itself from contacting with the material being treated, but in which a thickness of material and a character of material of such nature as to permit removal of solidified material Within the vessel by a shearing or disintegration ofthe coating itself are neither contemplated nor possible.

As stated hereinabove, the coating which I apply to the inner surface of a vessel in which mval of the coke from the vessel in a single hydrocarbon liquid is about to be coked is of a more or less friable charactenhowever, the coating is of a sufficiently cementitious lcharacter to be applied in a layer ofv substantial thickness and' Ymore friable at the temperature at which coking is effected, I may provide material which retains a'relatively high strength throughout the coking operation, but may subsequently be weakened or disintegrated in a simplemanner, as for lexample by treating it with water or other liquid having solvent or disintegrating properties with respect to the same, without material injury to or destruction of the coked mass.

My invention also contemplates the provision of an-apparatus' for coking hydrocarbon liquid which comprises a vessel, preferably more or less elongated -in configuration, having a lining of the character recited'` hereinabove and having also a discharge opening for removing coke therefrom the size of ywhich is sufficient to permit the reslug or mass, together with suitable means for exerting a discharging force .upon the coke for the purpose of shearing or disintegrating the lining material within the Vessel and thus expeiling the coke from Vthe vessel without materially destroying or lpulverizing the coke itself.

The lining or coating applied to the interior surface of the vessel preferably consists of loosely bonded granular or arenaceous materialv of suillciently cementitius and refractory character to be applied in a layer of substantial thickness and to resist the crushing force exerted by the material being coked while sufficiently friable after the coking has been completed 'to make possible its disintegration forl the purpose `of removing ythe coke from the vessel, and having a substantial-impervious surface asaforesaid.

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Thus, I may employ .a mixture lofl sand, clay y and a suitable bonding agent such as water glass or sodium silicate. For example, I may employ a mixture comprising substantially equal parts of sand and clay made into a ,mortar or paste of suitable consistency by means of a solution of sodium silicate inl water.

When the material employed to form the coating does not tend to form itsown impervious surface, or when it is desired to decrease whatever perviosity the surface of the lining may have,

the latter may be glazed in anyknown 'manner or may be rendered less lpervious by applying thereto a thin layer of impervious material, for

example, a metallic pigment. Thus, I may spray th lining or coating after it has been formed with a suspension of fiaked aluminum orbronzlng powder in a suitable vehicle..

As an alternative or supplementary mode of Y procedure I may employ a lining or coating consisting in. part of a material, `preferably more or less granular character and capable of being dis solved or disintegrated by a suitable agent after the coking operation has lbeen completed. Thus I may add a soluble salt, such as sodium (chloride,.or any other soluble material yof sulciently refractory character to the mix. fromwhich the lining or coating is made, thus providing a coat' ing comprising a mixture of soluble and insoluble particles. At the time the coke is lcooled, which is done with water in the usual manner, the solvent action ofthe water upon-the rsoluble constituents of the liner greatly facilitates the breaking down or disintegration of the lining or coating material and the removal of coke from the vessel. i,

In order that my invention may be fully set 5 forth and understood, I have illustrated in the drawing accompanying and forming a part of this specification various preferred forms in which my invention may b e practiced and em. bodied. In this drawing, 1

Figure 1 is a' more or less diagrammatic elevational view of .apparatus for effecting the cok- .ing of a hydrocarbon liquid in accordance with my present invention; y

Figure 2 is an enlarged vertical' sectional view showing the relation of the Wall of the coking chamber, the liner therefor and the material being coked; and

Figure 3 is a similar view, illustrating a different modiflcation of my invention.

Similar reference-numerals designate similar parts in each of the views ofthe drawing.

As illustrated in Figure 1, the' vessel I in which the coking takes place is preferably more or less elongated and cylindrical in configuration and 25 is provided with openings at either end thereof, which are provided in turn with closures 2 andv 3, respectively/and which openings are sufIicient-. ly large to permit the removal of the coked'mass from within the 4vessel in a single mass or slug. 30 Prior to introducing material to becoked into vessel I, I provide the interior surfaces of ythe, vessel I, or such portions thereof as may be expected to come into contactwith material being coked, with avlining or coating l which, in 35 the preferred instance diagrammatically illustrated in Figure 2, comprises a mixture of substantially equal parts of sand and claywith a.l solution of sodium silicate and whichcoating material is applied until a layer of this mortar or, 40 vcement of a .thickness of V4 inch'or more has been bulltup'on the wall of the vessel I.' After the lining or Icoating .4 has been applied it may if desired be dried in any` Vsuitable manner, as for example,` by passing hot gases through la the vessel I, although in most instances predryf` ing will be unnecessary, it beingsatisfactoryl to eect the drying of the lining l during the progress of the coking process by the heat of the material being coked. y 50 After the lining has been applied, the surface thereof mayif desired be coated with a layer l of impervious material, such, for example, as a thin layer of metallic paint, as illustrated in F18- ure 3.x Figure 2 is intended to show, however, in 55 a more or less diagrammatic way, the tendency of sodium silicate present in the material formingthe layer l to make the exposedsurface of the layer l substantially impervious by `forming a sodium silicate glaze over or through the' same. 0o while leaving the remaining portion of the lining or coating l lin a less glazed or more friable condition.

1 When the coating or lining has been prepared, hydrocarbon liquid to be coked, is introduced into e5 the vessel I and is maintained within the vessel' I within a sufllcient, temperature to effect ooklng thereof. In the instance illustrated inv Figure 1 a hydrocarbon liquid such, for example, as a reduced crude or a gas oil, is drawnfrom a suitable 70 source (not shown) -and is delivered by a pump I0 through a conduit vI into heating coils I 2 located within a suitable furnace I3, the heating `.being regulated with respect to the character of the material being heated to bring the liquid to 75 an undesirable deposition of coke or carbon within the heating coils I2.

The heated liquid or vapor, which may, for example, be at a temperature of 850 to 1050 F., then passes through a transfer line I6 having valved branches I and I6 into the vessel I, the admission being either to the top or to the bottom of the same or divided between the top and bottom of the vessel I. In the vessel I, separation of vapors and liquid occurs and the unvaporized liquid is coked by the contained heat of the material entering the vessel I. The vapors pass oil through a vapor outlet pipe 20, the coke building up within the vessel I but separated from the walls of the latter by means of the lining or coating d.

When the coking operation has been 'completed, that is to say, when a sufficient amount l pusher ram 2I of sufcient size with respect to the interior of the vessel I to cause the coked mass to be expelled from the bottom of the vessel I in a single mass or slug, this removal of the coke being. greatly facilitated by the disintegration of the more or less friable lining or coating It.

The coke may be cooled either before or after removing it from the vessel I in any suitable manner, as for example, bytreating it with water, the latter being especially desirable where, as has .been indicated hereinabove, the material comprising the lining il contains soluble constituents which may be dissolved by the water, thus assisting in the breaking down or disintegration of the lining prior to the removal ofcoke from the" vessel I. A

It will be obvious to those skilled in the art that, While I have described myinvention hereinabove with respect to one or more specic illustrative examples, my invention is not limited to the details of such exemplication but may variously be embodied and practiced within the scope of the claimhereinafter made.

I claim:

In the process'of coking hydrocarbon oil within a metal vessel, the steps which comprise lining the interior of the vessel with a cementitious layer of substantial thickness, sealing the entire exposed surface of said lining by applying a, thin metallic coating thereto, thereby preventing contact of oil to be coked with the inner cementitious layer, supplying oil to the vessel and maintaining it at a coking temperature until coked, thereby rendering said cementitious layer frangible, and then discharging the coke produced together with the linings.

HAROLD V. ATWELL.

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