US1942978A - Coking bituminous material - Google Patents

Description

Jan. 9, 1934. E. o. RHODES COKING BITUMINOUS MATERIAL Filed Feb. 9, 1929 3 Sheets-Sheet l IN VEN TOR.

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y AT ORN Jan. 9, 1934.- E. o. RHODES 1,942,978.

COKING BITUMINOUS MATERIAL IN VENTOR.

Patented Jan. 9, 1934 PATENT, oFFicE 1,942,978 COKING BITUMINoUs MATERIAL Edmund 0. Rhodes, Pittsburgh, Pa., assignor to The American Tar Products Company, a corporation oi' Delaware Application February 9, 1929. Serial No. 338,644

` 3 claims. (c1. 2oz-17) My invention relates to the coking of bituminous materials, either liquid or such as may be brought into a liquid or mobile condition by heating, and such, for example, as tar or pitch.

5 An object of my invention is to provide a process of reducing such materials to coke in externally heated coking retort ovens ofthe byproduct type, for example, those commonly used for coking coal, whereby certain disadvantages.

1o of the prior art may be avoided.

My invention has for further objects such other operative advantages or results as may hereinafter be found to obtain. y

Numerous attempts have been made in the past to accomplish the coking of tar and pitch in externally heated coking retort ovens, but such attempts have been subject to numerous disadvantagesand difiiculties and 4cannot be regarded as practical solutions of the problem. Some of these difliculties arose from the liquid nature of the material and its tendency to foam, which caused leakage through cracks in the retort walls and around the doors.- Also, the introduction of the material to be coked in a comparatively large `body into a highly heated retort in the manner of the prior art caused a. .chilling of the retort which resulted in the scaling off of the surfaces so exposed to heating and cooling, and also caused an undue expansion and contraction of the retort as a whole, the opening of the cracks between the bricks and the impairment of the cement, and from one and-all of these causes the retorts were rapidly deteriorated and injured."

On the other hand, when it was attempted to introduce the pitch or other material progressively and slowly into the retort, it was found that the ligh temperatures obtaining in the retort caused considerable cracking of the products of distillation and the formation of excessive 40 amounts of lampblack, anundesirable impurity. My invention obviates these diiliculties kand. disadvantages by performing the cokingof the pitch continuously and, at the same time, introducing into the retort the material to be coked,

, together with a s uitable quantity of superheated steam or other inert gas. The material to be coked is introduced in relativelysmall quantity at a time into the highly heated retort so that the chilling effect at any time is so small compared with the extent of the retort and the high heat of the same that the above-described injuries cannot result. Nevertheless the pitch is Aintroduced into the retort with suicient rapidity so that `a batch of substantially pure coke in quantities equal to the capacity of the retort is produce without undue expenditure of time.

My invention may be applied to. the coking of substantially any bituminous material that may be liquefied, or otherwise brought into a mobile condition, and which ,is capable of being coked. However, when tar is to be reduced to coke, itis preferred to subject it to a preliminary distillation operation to remove its more volatile constituents and to reduce. the bituminous residue to 55 pitch, without however destroying its essentiallyv liquid nature at the temperature of distillation.

Moreover, by thus rst removing the lighter distillates by ordinary distillation means, a larger total yield of oils is made possible, as cracking o1' 70 such light constituents, -which would occur if the entire distillation tookA place in the coking retort, is thereby avoided.

When pitch has previously been obtained or prepared and is therefore found in a more or less solid or even' brittle condition at ordinary temperatures, it is necessary to again reduce the pitch to a mobile condition, for example, by heating it in order that it may be introduced into the coking retort oven without difculty. 30

In any event, the hot mobile material is introj duced directly into the coking retort oven in the manner herein described, together with steam or other inert gas, and in such manner as to prevent chilling of the material and consequent plugging g5 of the distributing apparatus due to solidication of the bituminous material therein.

In order that my invention may be clearly' set forth and understood, I now describe with reference to the accompanying drawings a preferred .90 manner in which it may be practiced and embodied, but without limiting the c1aimed inven tion specincally to thedetails of ,such illustrative examples.` In the drawings,

Figure 1 is a more or less diagrammatic view of apparatus for reducing tar to coke and for recoveringr the products of distillation, said apparatus including a portion of `a battery o1' byproduct coking retort ovens of well known type;

Fig. 2 is a vertical sectional view of a horizon- 100 tal coking -retort oven provided with 4means for accomplishing the coking of bituminus material Yaccording to the present invention; and

Fig. 3 is a view in vertical section of meanso for introducing liquid bituminous material and steam or other inert gas into acoking retort oven.

Similar numerals designate similar parts in each of the several views of the drawings.

Referring to the drawings and especially to Fig. l'there is shown at i a tank for the storage 110 of tar or similar material which it is desired toreduce to coke. For this purpose there is employed a still 2 for first reducing the tar to pitch, and a coking retort oven 3 for subsequently reducing the pitch or other tarry residue to coke.

The coking retort oven 3 may be one of a plurality of similar coking retort ovens having heating iiues 3' in the side walls and forming a battery 4. The remaining ovens 5 of the battery 4 may be employed for the same purpose or for the coking of coal in the usual manner. It is o'f-ten advantageous thus to employ one or more of the coke ovens of a battery employed primarily for colringI coal for the reduction to coke of the tar produced in the coking operation carried on in the remaining ovens.

Sullicient tar is introduced from the tank 1 by means of a pump 7 and a line 8 to ll the still 2 to a predetermined level and the tar in the still 2 is then distilled in the usual manner, by means of burners 9 or other means for applying heat. The products of ldistillation pass from the still 2 through a vapor line 10 into a condenser 11 where they are condensed by being subjected to a spray of water from a line 12 and pump 13. The mixture of condensed oils and water then passes through a line 14 to a separating tank 15. y

By means of the pump 13 and the line 12, a continuous recirculation of water is maintained, enough fresh water being introduced from the make-up water line 16 to keep the temperature of the condensing system sufficiently high to prevent condensation of heavy resinous products of distillation from the retort oven, but low enough to condense the lower boiling distillates, for example, at about C.-

Excess water is removed from the separating tank 15 through a line 17 and the condensed oils are drawn by a pump 18 through lines 19 and 20 and are pumped-into a receiver 21. Fixed gases which do not condense in the condenser 11 escape through a line 23- and are dealt with as will be describedvhereinbelow.A

When the residue remaining within the still 2 has attained the desired quality, the tar is pumped into the still 2 at a rate suilicient to maintain the temperature in the still 2 substantially constant, and at the same time pitchis pumped fromthe still 2 into the cokingretort oven 3, which has previously been heated to carbonization temperatures.

By means ofv a submerged pump 25 within the still 2 and below the surface of the pitch. contained therein, pitch is continuously withdrawn from the stilll 2 through a line 26 in amount considerably larger than is required for the filling of the coking retort oven 3, and this pitch passes through a line 27 having a plurality of oiftake valves 28 corresponding to the charging holes in the coking retort oven 3 fand the excess pitch returns'through a line 29 to the still 2. -v

In this manner a constant recirculation of pitch through the lines 26, 27 'and 29 is provided so that the pitch remains iluid, and chilling and consequent stoppage are-prevented. Provision should also be made so that in the event of a cessation of pumping the liquid pitch will drain out of the lines 26, 27 and 29 and return tothe still 2. fr

The valves 28 are illustrated in detail in Fig. -3 and as there shown are so constructed as to oier` comparatively little obstruction to the iiowJ of liquid through the line 27. Each valve 23 is provided with an oiftake 30 extending down into the coking retort oven 3 through` a charging hole l31 thereof and througha suitable opening 32 in the charging hole cover 33, the opening 32 being luted with iireclay as shown. i

The oiftake 30v is provided with an extension 34 extending into the interior of the valve 28 and terminating in a valve seat 35, the flow of pitch through the extension 34 being regulated by regulating the distance between the valve seat 35 and a corresponding valve member 36. The valve member 36l is conveniently carried by a hollow spindle 37 extending into the interior of the extension 34 and which also passes through a gland 38 and communicates through a valve 40 with a line 4l supplying steam or other inert gas. By means of a hand wheel 42 suitably disposed, the

- spindle 37 and valve member 36 may be caused to be raised or lowered, thus opening or closing the orice through `which pitch discharges from the line 27 through'the offtake 30 into the cok-A ing retort oven 3. y

A hand wheel 45 is provided which engages the extension 34 and offtake 30 by rotation ofwhich l connection between these two may be severed land the oitake SOthereby withdrawn from the charging hole 31 by means of a suitable handle 46.100

The end'of the oitake`30 terminating` within the coking retort oven 3 is provided with a suitable iiare 47 having a relatively long and narrow opening co-axially disposed with the longitudinal axis of the coking retort oven, 'and whereby 105 a more or less fan shaped spray of liquid is secured which impinges the least possible amount on the walls of the coking retort oven.

The valves 28 are so regulated as to allow a suitable amount of the pitch passing through vthe l line 27 to discharge through the oitakes 30 into the interior of the coking retort oven 3, the rate of ilow being so regulated as to accomplish the filling of the retort in the minimum time, without however allowing the coking' retort oven 3 115 to contain a large amount of liquid material at any one time. In short, the introduction of the material to be coked is regulated correspondingly to the progress of solidication of the charge Within the coking retort oven 3. l

While the introduction of the material is preferably accomplished substantially continuously, this does not preclude such intermittent operation as results from the frequent and regular opening and closing ofthe valves 28. It has been found that in some instances, particularly where pitch is remelted, there may' be some diiliculty in keeping relatively small and continuously operating vvalves open and free, and under such circumstances somewhatv larger valves may be 13() used, these valves being operated intermittently. However, the quantities discharged at any one time are comparatively small and the intervals between successive periods are preferably kept very small so that such intermittent charging 1'35 eil'ects practically the same results as continuous charging and may be regarded as substantially continuous for the purposes of the present specification.

The actual time required to fill the coking retort oven and `to complete the coking of the charge will, of course, vary considerably with the size of bthe oven, the nature of the material charged, the temperaturesl carried in the heating flues," and the like, and will, in each individual instance; be governed largely by the discretion of the operator. Howeverfin order that this description may be complete, the results of a typical procedure are given below.

VA colclng retort oven 'may be employed which 150 ture.

is of standard dimensions, Cfor example, about 40 feet long, about 10 feet high, having an average Width of about 16 inches, and comprising a portion of a batterycf such ovens, ordinarily employed for coking coal.` The tar to be reduced to coke is rst distilled in a tank still operated continuously, tar being introduced at such a rate as to maintain the temperature of the charge at a substantially constant tempera- The charging of the coking retort oven in this instance will ordinarily require approximately six hours, the oven being fllled to a depth of about 61/2 or 7 feet. After filling the oven, the charge is left in the oven for aproximately 10 hours to complete lthe coking operation, after which coke is discharged from the oven by a pushing operation by means of the customary pushing apparatus employed in removing coal coke from by-product coke ovens. The entire operation thus consumes about 16 hours, more or less.

During the shrinking period of about 10 hoursVA the distillation of tar in the still is continued. The level of material within the still rises during this period until, at the conclusion of the shrinking period and after discharge and resealing of the coking retort oven, a suilicient supply has been built up in the still to again ll the oven. This process is repeated as long as is desired.A

The extent to which the distillation is carried in theA primary still before the tar is discharged into the -coking retort oven for coking will depend largely upon the particular conditions involved, but ordinarily I prefer to predistill the tar to pitch having a melting point in the neighborhood of 300 F. It is, of course, tobe borne in mind that the farther the distillation is carried in the primary stage the smaller the loss of oils due to cracking inthe coking stage. of the pitch residue rises, the dimculties encountered in handling it and keeping it fluid also increase, and for many purposes it may be desirable to carry the distillation in the primary still to a point where the residue has a considerably lower melting point than those hereinabove specified; for example, from 200 to 250 F. Such melting points are of course determined by the standard methods used in practice.

When the desired quantity of pitch has been accumulated within the coking retort oven 3, the `valves 28 and 40 are closed and the otakes 30, if no cooling means, such as steam jackets, are provided, may then be withdrawn from the charging holes 31 to heat subsisting within the latter, and the holes 32 in the charging covers 33 are then luted with clay or similar material to prevent escape` of gaseous products of distillation.

'Ihe steam and vapors produced by the distillation 'of the pitch are withdrawn through the usual standpipe 50, but are prevented from passing into the. collecting main 51 which serves the remaining ovens of the battery by a suitable valve 52, similar to those generally provided in standpipes, which is kept closed, and instead pass through a vapor line 53 to the condenser 11 where they mingle with the -gases coming from the still 2 and are condensed. The incondensable gases then pass through lines 23and 54, having a valve 55, into the collecting main 51 where they mingle with the coal gas produced inathe remaining ovens 5,' on else pass On the other hand, as the melting pointl protect them from the high,

through an outlet 56 having a valve 57 to the atmosphereor to whatever use may be desired Y for them, l

Suitable means should be provided for maintaining a proper pressure within the coking retort oven 3, preferably of automatic type. Of course, when the -incondensable gases are led into the collecting main 51 serving other coking retort ovens of the battery, the usual pressure regulator serving the other ovens 5 also serves to regulate pressure conditions within the oven 3'.

It shouldbe observedthat when steam is employed as the inert gas in introducing the bituminous material into the coking retort oven, the incondensable gases produced inthe distillation of the pitch contain substantially no inerts and may readily be mingled with the gases coming from the remaining ovens 5, f'but where some other inert gas, such as carbon dioxide or nitrogen, is employed for this purpose, the mixture of incondensable gases and inert gas may ordinarily not be introduced into the coal gas.

After the coking retort oven 3 has been charged with pitch in the manner recited above and the oiftakes 30 have been withdrawn, the coking operation is continued until all or nearly all of the volatile matter has been driven off, leaving coke of good quality. This operation generally requires from eight to ten hours when the oven is kept at carbonizing temperatures, depending also upon the size of the oven,

and also results in the shrinking of the coke'd ample, it is not limited to suchspeciflc embodiment, but may variously be practiced and embodied within the scope of the claims hereinafter made.

I claim as my invention:

1. A process of manufacturing coke from bituminous material selected from a group consisting of liquid bituminous material and liqueflable bituminous material in a by-product o'ven having side walls with heating flues extending substantially through the entire height of the walls, which process comprises heating the side walls of the oven to maintain the coking chamber at coking temperature, spraying into the coking chamber said bituminous material with a gaseous medium substantially free from uncombined oxygen so as to which on passing downwardly through the oven -is substantially freed of foaming constituents that cause excessive foaming, regulating the feed of the bituminous material in the oven so that the liquid sprayed bituminous material'collected in the oven at any time will not cause undue chilling of the walls of the1 oven, and continuing the coking of collected residual matter to bring about shrinkage thereof to free coke from the sidewalls of the oven and to form acoke that is removable en masse from the oven by a pushing operation, and pushing the coke out of the oven'. 2. A process of manufacturing coke from bituminous material selected from agroup consisting of liquid bituminous material and liqueflable ing side walls with heating ues extending substantially through the height of the walls, which process comprises heating the side wallshf the' oven to maintain the coking chamber at coking temperature, spraying into the coking chamber said bituminous material with steam so as to produce a liquid spray which on passing downwardly through the oven is substantially freed of foaming constituents that cause excessive foaming, regulating the feed of the bituminous material in the oven so ,that the liquid sprayed bituminous material collected in the oven at any time will not cause undue chilling of the walls of the oven, and continuing the coking of collected residual matter to bring about shrinkage thereof to free coke from the side Walls of the oven and to form a Acoke that is removable en masse from the oven by a pushing operation, and pushing the coke out ofthe oven.

3. A process of manufacturing coke from pitch in a by-product oven having side walls with heating ilues extending substantially through the entiretheight of the walls, which process comprises heating the side walls of the oven to maintain the coking chamber at coking temperature, spraying into the colclng chamber said pitch with a gaseous medium substantially free from uncombined engen so as to produce a liquid spray which on passing downwardly through the oven is substantially freed -of foaming constituents that cause excessive foaming, regulating the feed of the pitch in the oven so that the liquid sprayed pitch collected in the oven at anytime will not cause undue 'chilling of the lwalls of the oven, and continuing the coking of collected residual matter to bring about shrinkage thereof to free coke from the side walls of the oven and to form a coke that is removable en masse from the oven by a pushing operation, and pushing the coke out of the oven.

V@Mmm o. RHODES.

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