US2064715A - Coking liquid hydrocarbons - Google Patents

Description

Dec. 15, 1936.

H. v. ATWELL COKING LIQUID HYDROGARBONS 7 Filed March 29, 1955 *INVENTOR' HAROLD v. ATWELL BY -75- M ATTORNEY Patented Dec. 15, 193 6 I v Q i UNITED. STATES PATENT OFFICE COKING LIQUID nYmtooA tBo s Harold V. Atwell White Plains, N. -Y assignor to Gasoline Products Company, -Inc., Newark, N. .L, a corporation of Delaware Application March 29, 1933, Serial No. 663,291

' 1 Claim. (01. 202-14 v This application relates to the distillation of templates the formation of, a preheatedbed of liquid or liquefiable hydrocarbons, such as hycoke or the like upon a moving support, the subdrocarbon oils, tars, and pitches, forthe purpose sequent introduction thereon of material to be i of reducing the same to coke. r h coked, and finally the removal of the coke, my

' My invention has for an object the provision invention further contemplates, where desired, of a method whereby hydrocarbon material of subjecting the combined bed of materials to furthe character indicated may be reduced to coke ther heating or combustion and further introducin a continuous manner without causing the coke tion of material to be coked, the combined bed in I thus formedto adhere to the surface upon which this instance passing through a plurality of alit issupported and having such additional imternated heating and carbonizing zones. provements or operative advantages and results My inven ion fur h r contemplates the r as may hereinafter be found'to obtain. tionof the materials forming the bed after the My invention contemplates introducing a ma coking or carbonizing operation has been com-' terial oi the character recited hereinabove, prefpleted in such manner as to afford a separation erably in ,a heated condition upon a moving bed of the mainin p rti ns f t u d r y d ll of preheated finely. divided coke .or pre-carbonof finely divided material and the relatively more ized hydrocarbon material at such a rate that the valuable mass or layer of c ke v lyi th sam liquid material is solidified or reduced to a subv It Wi l be understood that the term coke as stantially non-fluid condition or coked by the mploy d h r in m y signate products With- 0 heat of the underlying pre formed bed of coke in a rather wide range of p p r due to the so 1 before it has had an opportunity to completely fact that various materials coke at difierent tempenetrate the same, so that the entire bed of carperatures, and due also to the fact that carbonibonized material does not form a homogeneous zation is a more or l ss gr du l hang As the mass but there remains a layer of material not terms are generally used in the art, coke is a in a coalesced condition between the newly carbonized non-liquefiable material having a -formed solidified mass of coking or coked matedefinite cell structure, while fpitch is a material and the support upon which the bed is rial having a determinable melting point and not formed, thereby preventing the newly formed having a definite cell structurabut there are coke from adhering to the support and making materials lying within an intermediate range possible the easy removal of the coke from the which are extremely difiicult to classify as coke support. or pitch.

My invention further contemplates preheat- The term cok'efias employed herein therefore -ing the coke' or carbonized material supplied to does not exclude a product so hard as to be practhe moving support to form a bed thereon, either tically indistinguishable from a true coke, nor

prior to distributing the coke upon the support semi-coke, n a wmp a coke, nor a or after the bed is formed, the heating beingacproduct consisting in part of true coke and part complished by any suitable means, as for exof pitch, as any ofsuch products, as well as a f ample, by partial combustion of the coke or by true coke, may be produced by means of my inpassing hot gas therethrough, or both. vention, and the specific nature of the final While coke from any source may be employed product will vary with the nature of the mate- 40 to form the initial bed upon which the material rial or materialstreated and the temperature at to be coked is sprayed, my invention further conwhich the coking or carbonizing proceeds.

templates segregating a portion of the coke pro- While my invention is especially suitable for duced in the process, and preferably the more the coking or carbonizing of petroleum hydroflnely divided portions thereof, and employing the carbons such, for example, as residuums obtained segregated portion of coke to form a preheated in distilling-or cracking petroleum or petroleum bed, and it is an advantage of my invention that oils, it may also be employed for the coking of when operating in this manner all or a considerother hydrocarbon liquids or liqueilable hydroable portion of the fines produced may ultimately carbon materials, such, for example, as coal tar,

be combined in the upper portionsof the bedwithwater-gas tar, oil-gas "tar and other tars, and: material being reduced to pitch or coke and thus pitches. obtained therefrom. Mixtures of m t solidified to form masses of relatively large size rial of petroleum and non-petroleum origin may and relatively'higli value as compared with more also be coked in accordance with my invention. finely. divided materials. Thus I may employ my invention for the purpose While in itsslmplest form my invention conof making a high-grade or. metallurgical coke 5 from petroleum coke of relatively low-grade character, as for example by spraying tar or the like into, a bed of the latter and coking the whole at a high temperature, preferably in excess of about 1300 F.

I I may also employ my invention to coke various materials of liquefiable character such for example as "amalgams" of coal and non-solvent oil or solutions of coal in tar, tar oil or other hydrocarbon oil having solvent properties with respect thereto. ,Such materials may'vary in character from materials purely liquid at atmospheric temperature to materials which are semi-solid or solid at atmospheric temperature. I

In most instances, it is preferred to introduce the material to be coked at an elevated temperature, for example, from about 200 to about 850 F. Thus, residuum drawn oif hot from an oilcracking or distilling operation maybe discharged directly, without substantial cooling, upon the bed where it is to be coked.

It is not necessary, however, that the material to be coked be heated prior to its introduction onto the coking' bed. Thus, in the case of pitch or other material solid at atmospheric temperature, while it is preferred to discharge these upon the coke bed at such temperaturethat they are fluid and may be introduced through a suitablespraying means, such materials may be introduced in a solid or semi-solid condition where desired, the introduction of material in this condition being facilitated by pulverizing the same prior. to

their introduction.

The coke or carbonized or partly carbonized .material from which the underlying bed. is formed is preferably in a finely divided condition, and may be similar in origin to the material being coked ormay be derived from other sources. Thus, cokes obtained from coal, coal-tar pitch, petroleum oils and the like may be employed, petroleum coke being preferred, and the material to be coked may in .each case comprise an oil, tar or pitch either from a similar origin or from a different origin; thus the bed being sub-- jected to coking may comprise petroleum coke and coal tar or coal-tar pitch.

The temperature at which the coking operation is conducted may vary considerably from a lowtemperature coking range of, for example, from about 800 F. .to 1300 F., to a high-temperature coking range of, for example, from about 1500 to 2000'F;, in accordance with the character of the material treated and the nature of the results desired and it will therefore be understood that, in its broad aspect, my invention is not limited to any specific temperature within a range suitable for coking or substantial coking.

In order that my invention may clearly be set forth and understood, I now describe, with reference to the drawing accompanying and forming part of this specification, a preferred form and,

endless chainor belt I mounted upon and driven by sprocket wheels 2. Such travelling supports.

the upper surface of the chain support I moves from left to right as shown in Figure 1. I

For the purpose of maintaining a supply of previously coked material, such, for example, as

petroleum coke, pitch coke, orvcoke made from coal, to be supplied to the moving support I, I provide a chamber 3 which is connected by means of a passageway 4 having a feed-regulating device 5 to the interior of a chamber 6 which encloses the support I.

Coke may be supplied to the chamber 3 through a charging device comprising a closed feed hop- I per 1 having a charging valve 8 and a filling valve 9. The valves 8 and 9 are adapted to be operated alternately, whereby coke may be charged into the chamber 3 from time to time as desired without permitting the escape of gases from the interior of the chamber 3 through the charging opening. Such charging devices are common in the art of gas manufacture and need not be described in further detail here.

Coke, preferably in a heated condition, is delivered from the chamber 3 to the support I through the passageway, 4 at such rate that it forms a uniform bed I I havinga thickness of, for example, from 2" to 8", upon the moving support I. Where the material comprising the bed II is not already in a sufilciently highly heated condition, air or other heating gas may be suppassing through the duct Il may be diverted to pass through the body of coke within the cham- Thus,.I may bring the coke bed I I to incan- -descence by introducing air through the conduit I3 and duct I2, and the products of combustion may be passed .wholly or entirely through the coke in thechamber 3 to preheat the same, additional air being supplied, if desired, through the conduit 2| and the grate 23 to assist in the preheating of the coke, either by direct combustion of the same or by combustion of carbon monoxide in the gases of combustion entering the chamber 3 through the duct I5. e The gases leaving the upper surface of the b 'I hare prevented from .escaping to other portions .of the interior of the chamber 6 'by means of spaced vertical walls 30 and 3| having drag links 32 and 33, respectively, adapted to ride on the upper surface of the support I or the bed H, as the case may be, and adapted to form a suflicient seal against passage of gases therethrough;

. The coke bed Ii thus passes under the wall 3| and drag links 33 in a highly heatedcondition, preferably at such temperature as to be incandescent, and in any event not below 1300" F., and

immediately after passing under the wall 3|, hy-

' drocarbon material to be coked'is introduced on to the upper surface of thehighly heated coke bed ll. spray 35, of which a plurality may be "employed, which is supplied with hydrocarbon material in a liquid state through a conduit 36 having a valve 31 and communicating with asuitable source (not shown) of such material. By way of example, residual petroleum oil may be supplied to the spray or sprays 35 in a highly heated condition from a suitable point in a cracking or distilling 1 operation.

Where hydrocarbon material to cokedis solid at the temperature at which it is introduced,

although liqueflable at the temperature of the bed ll prior to coking thereof, some suitable means for feeding material in solid form on to the bed H may be substituted for the sprays 35. For example, a passageway and flow regulating means similar 'to those illustrated at 4 and 5, respectively, may be substituted for the sprays 35,

- conduits 36 and valves 31.

The rate of introduction of the hydrocarbon material is so regulated in accordance with the depth and temperature of the bed II, the temperature of the material'being introduced and the coking tendency of the hydrocarbon material to be coked,- as well as other factors which will be apparent to those skilled in the art, as to cause the hydrocarbon material introduced to the top of the highly heated bed II to be coked or at least reduced to a substantially non-fluid condition before it" penetrates the full depth of the bed ll, so that substantially no materialin a fluid or sticky condition reaches the upper surfaces of the moving support I.

, It -will, of course, be apparent that in actual praetice especially when working with a relatively thin bed Ii, it will be practically unavoidable to completely prevent material introduced through the spray 35 from coming into contact with the moving support lat any point, but the introduction of the hydrocarbon material may easily be regulated so that full penetration of the bed .I i, if it occurs at all,'occurs only to a,

very minor extent and inisolated spots, so that substantally none ofv the troublesome adherence of sticky material or coke in the process of formation which has been experienced in the prior art takes place in accordance with my invention, and the newly formed coke may readily be removed from the support I due to the fact that the mass of newly formed coke (both after and before coking is completed) isseparated at substantially every' point from the surface of the moving support i by a layer of coke in a nonsticky and non-coalescent condition. I A third wall or partition 40, having drag ends 4| adapted to ride on the upper surfaceofthe bed42 of newly formed coke which overlies the initially supplied bed II, is provided at a sumcient distance from a wall 3i. to allow for sub,-

, stantially complete-coking oi the hydrocarbon material introduced through the sprays 35. The aasesand vapors liberated during the coking Thus, in Figure 1, I have. illustrated a,'

'5 arranged side by side. The ofl-take pipe 45 tain either a substantially atmospheric pressure or a pressure a little below or a'little above atoperation are removed from that portion of the interior of the chamber 5 lying above the support 1 between thewalls 3i and 40 through an oif-take pipe 45 leading to a collecting main 43 which may serve a plurality of coking chambers 5 is preferably, provided with a regulating valve 41 and with valved sprays 48 communicating with'a, source 49 of gas oil, tar,or the like. Such oil may be introduced to the off-take 45 and the main 46 to prevent formation and deposition of coke from heavy pitch within the latterr The main'46 is preferably connected to an exhauster (not shown) which is so "regulated as to mainmospheric in the carbonizing space within the chamber 5.

Situated below the upper surface of that portion of the support .i lying between the walls 3| and 40, I may provide a plurality of refractorywalled flues 5|, throughwhich heating gases may be passed for the purpose of transferringadditional heat to the material lying upon the moving support I to promote the coking operation.

While the material passing under the wall 40 may be removed from the apparatus as a whole, without attempting to separate it into its constituents, I prefer to separate the newly formed bed of coke 42 from the remaining portions of; thebed ll. I may accomplish this by suitable means such, for example, as an adjustable plate 53 located near the righthand end of the supthe purpose of quenching all or a portion of the port I as shown in the drawing. The sharp respect to the support I as to divide the material moving forward on the support I at a point I which marks the substantial termination of the bed 42 of newly formed coke or, if desired, at" a slightly lower point where the plate 53 passes readily through the advancing residual portion of the coke bed ll.v It will, of course, be obvious that the upper. portions of the coke bed II will be largely combined with and absorbed into the newly formed coke bed 42, and it is one of the advantages. of my invention that a considerable part of the relatively finely divided coke comprising the under-- lying bed ll may thus be combined or 'recoked in such manner as to produce coke of larger size and consequently increased value.

That portion of the coke which passes under the plate 53 is removed by suitable means, for example, a conveyor 55,.whi1e that portion of the coke. which passes over the upper surface of 55 the plate 53 may be delivered to a second conveyor 56 which removes it from the chamber 6. A suitable'water spray 51 may be provided for coke, and the steam vapors liberated "by such quenching may be removed through an'oif-take conduit 53.

For the purpose, of removing any small portions of coke or sticky, partlycarbonized mate- I rial which may occasionally adhere to the surface of the travelling support I provide a .ro-'- tating member 60 preferably having a toothed or serrated surface asshown. It will be understood, however, that it is one of the advantages of my present invention that such adherence of coke or, sticky material to the support I is re--. duced to a minimum and that with properly controlled, operation the member fill may be found unnecessary, andin any eventits purpose is 7 merely to provide against incidental irregularities in the operation of the process.

As an alternative mode of operation, the material charged into the highly heated coke bed ll may comprise a pasty or semi-solid mass obtained by mixing coke with a liqueflable hydrocarbon material. The low fluidity of such a mixture, especially when prepared by mixing heated coke with tar, pitch or the like, serves to provide a further safeguard against passage of liquid through the interstices of the support I, and reduces the depth of the bed H required.

While I have illustrated and described ,a preterrediorm of apparatus by means of which my invention may be practiced and embodied, it will readily be understood by those skilled in the art that my process is adapted to be performed in apparatus or various kinds, such, or example, as that described and claimed in the copending application of William 1'. Moore, Serial No. 654,846, filed February 2, 1933, in which petroleum oils are distilled and coked by radiant heat from a suitable source on a bed of non-liqueflable carbonaceous material fed on to a moving support.

It will further be understood that my process is not limited to the details 01' the various illust'rative examples which have been" set forth hereinabove, but 18 to be broadly OODStlUCd within the scope of the claim hereinafter made;

I claim:

The method 01' coking heavy hydrocarbon oil which comprises forming a bed of loose, non

-coh'esive petroleum coke pieces upon a moving support, heating said bed to a temperature substantially in excess of a minimum coking temperature for said oil. then supplying said oil to the upper portion of said heated bed as it is moved forward upon said support, and regulating the temperature, the rate of introduction of the oil,

the rate of travel 01' the bed on the support and HAROLD V. ATWELL.

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