US1891606A - Coking pitch - Google Patents

Description

Dec. 20, 1932. A. H. RADAscH 1,891,605

CQKING FITCH ATTORNEYS Dec. 20, 1932-. A. H. RADAscH 1,891,606

COKING FITCH Filed Dec. ze, 1929 2 sheets-sheep 2 metallurgical' purposes,

ing coking. 45 pitch 1s present Patented Dec. 20, 1 932 UNITED STATES PATENT OFFICE .ARTHUR H. RADASGH, 0F SOUTH ORANGE, NEW JERSEY, ASSIGNOB T0 THE :BARRETT COMPANY, 0F NEW YORK, N. Y., A COEPOBATION OF NEW JERSEY COKING PITGH Application led December 28, 1929. Serial No. 417,078.

This invention relates to the productionjof coke from pitch. According to this invention, a coke mass is produced by gradually supplying pitch to a coking vessel and coking it therein through indirect heating means, and as the mass of coke increases by the addition of pitch and its conversion to coke, the zone of the coking vessel to which the heat is applied is changed so that the areaof intense heating is extended upwards following the increase in height of the oven charge; the heat supply to the lower part of the oven may eventually be reduced since this part of the.

charge will be completely coked before the upper part. A

.Various methods have been suggested for converting pitch to coke. According to some of these methods, a large body of pitch is heated and converted to coke. On heating such a large body, convection currents are set up within the body and gases and vapors are given ot with resultant ebullition of the body which interferes with the formation of a compact andsolid coke such as is -desirable for causes stoppages of gas ,outlets by the foam produced and has other operating drawbacks. Processes which involve agitation of the pitch or coke during the coking process and processes whichinvolve continuously moving the mass of coking `material, such as continuous processes 1n which pitch is supplied to one end of a coking vessel and the coke produced is withdrawn from the other, tend to prevent the formation of large pieces'of strong compact coke suitable for metallurgical or foundry purposes. According to the present process the coking is conducted while the pitch is maintained substantially stationary, that is, it is not agitated byI outside means Aor continuously passed through a coking vessel. Some motion of the pitch may-take place due to the nature Aof the pitch'and of the-reactions occurring dur- However, only a small body of in the coking vessel at any .tery may be used simultaneously.

one time and that which is present is on top of the charge so that disturbances within the pitch vdue to convection currents and ebullition are reduced to a minimum.

According to this invention, pitch may be converted to coke in an oven such as. a coke Voven or an oven similar in construction to a coke oven. The bottom portion of the 'oven is heated and pitch is added to the oven and.

the temperature of the pitch is raised to the coking temperature. Additional pitch is gradually added to the oven.' The pitch may be added to the oven continuously as by adding the pitch gradually in a 'continuous stream, or small amounts may beradded at spaced intervals, or larger amounts, e. g. one quarter to one third of the charge may be added at one time. As the pitch is added to the oven and the material in the oven is coked, the zone of maximum heating is extended upwards so that intense heat is applied to the freshly added pitch and to the coking mass; furthermore, it may be-desii'`- able to reduce the amount of heat supplied to the lower portions of the oven, where the coklng is completed earlier than at the top.

The oven in which pitch is coked, accord-- ing to this invention, is advantageously constructed of fire-brick, silica brick, etc. It is heatedby meansl of flues embedded in the walls of the oven, and there may also be ues 1n the sole of the oven.' A single oven may be employed or all or several ovens of abatmore than one oven is emloyed, the ovens may advantageously be c arged in series, and when the coking has been completed, they will then be pushed in series and recharged. When individual ovens of a series are employed in this manner they are advantageously equipped with separate heating ues, but when several ovens are employed and allof the ovens are charged andpushed at substantially the `same time, the same heating flues may be employed for heating two 90 When r adjacent ovens. The ovens may be heated in any suitable manner. Valve means may be provided` to direct the hot flue gases through any selected fines, and to sluit them o' from other llues, and tochange the fiues through which the hot fiue gases are passed, as desired; or a bank of continuous flues may be employed with burners for raising any selected flue or flues to intense heat.

Pitch may be coked in the ovens of an ordinary coke oven battery, according to .this invention. The individual ovens of 5,"coke oven battery are ordinarily heated by the combustion of gas, etc., with preheated air, and the regenerator or recuperator in which the air is preheated is common to the ovensA of the battery. In a battery of coke ovens of the Samet-Solvay type, for example, it is customary to preheat the air in a regenerator, and this preheated air is admitted to the heating flues which are ordinarilyarranged horizontally. The heated air is admitted alternately to the t'op flue and the bottom flue, The arrangement of the llues andair passages is such that when the valves controlling the flow of waste gases and air through the regenerators are shifted to change the direction of flow of the air and waste gases, the preheated air which is introduced'into the upper flue, for example, is then introduced into the bottom flue, or vice versa, and hot waste gases which esca through the bottom flue then escape throug the upper flue. This change is made at regular intervals of, for example, thirteen or fifteen minutes. This change in the How of the preheated air and the hot waste combustion gases through the flue's, provides increased combustion efficiency by affording a supply of preheated air for the burners, but prevents burning out of the vregenerators through overheating. By varying the position in the flues in which the most vintense combustion takes place, the area of intensev heating may be changed. This Semet-Solvay type of oven, which is equipped with horizontal lues, is particularly Well adapted to the coking of pitch according to this invention.l

The ovens may be rectangular in cross-section, or they may taper toward the top or toward the bottom, or the ovens may taper toward one end to ai'd in from the. ovens.

pushing the coke `The pitch to be 'coked may be produced by the distillation of tar, or it may be pitch which has been directly recovered from hot coaldistillation gases by cleaning them at a high temperature, or-pitch resulting from a combination of these two processesmaybe coked. Pitch of high melting point, for ex,- ample, pitch with a melting point of 350 or 400 F. or even higher, is to be preferred to pitch of lower melting point. Lower melting point pitches are advantageously distilied to pitches of higher melting point in apparatus designed for the production of these highcr melting pointpitches before being subjected to the coking operation contemplated by this invention. Pitches of higher melting point are to bc preferred since there is less danger of foaming with such higher melting point' pitches and these pitches are more readily and rapidly transformed to a plastic or solid mass, and the possibility of leakage through the Walls and Vsole of the oven is thus reduced.

The pitch is advantageously added to the oven in a melted condition andpreferably in a hot, thinly fluid state. Such pitch readily spreads over the mass of coking material in the oven. lVhere necessary any suitable means for spreading the pitch may be employed. Pitch may be added to the oven in solid form where desirable.

According to a preferred method of carrying out the invention, the oven is first heated by passing hot combustion gases through flues at the bottom of the oven. These flues may be located in the sole of the oven oi` at the bottom of the side-Walls, or the hot gases may be passed through fines located both in `the sole of the oven and at the bottom of the side-walls.

Then an oven is employed for coking successive batches of pitch, the first portion of each successive batch is advantageously charged to the oven before the heat supplied to the oven in coking the previous batch has been entirely dissipated and while the oven.

is' still at a high temperature. It is advantageous to keep the walls of the oven at a relatively high temperature at all times since repeated heating and cooling of the walls over considerable temperature ranges is liable to produce cracks in the walls and sole of the oven. When' the pitch is coked in ovens of a battery of the Semet-Solvay type, the preheated air andhot waste gases passing through the ilues keep the oven walls hot at allv times.

The pitch is added to the oven gradually, and after the pitch first added to the oven has been heated to a coking temperature and formed a mass of solid or semi-solid coke or semi-coke, sutlicient additionalpitch is added to the oven to form a layer of pitch on the already formed semi-coke or coke over the Wholearea of the oven. Pitch is thus advantageouslyadded in increments while the coking proceeds until the entire charge is added to the oven. As the mass of coking material on ,the bottom of the oven becomes too deep to allow efficient transfer of heat from the bottom flues to fresh Aincrements of pitch added on top of the coking mass, filles above the bottom flues are successively brought to high temperature. The temperature of the combustion gases passing through the fines at the bottom of the oven may subsequently be considerably reduced. As the coking pnotion of fuel gases into ceeds and .added increments of pitch are coked, the mass of coke in the` oven increases and the oven is filled more and more with coke and the coking mass. As the layer of coke builds up in the oven, and the mass being coked, which is on top of the mass of coke already produced in the oven, becomes further and further removed above the hottest iues, the ues next above these are brought to high temperature and eventually the temperature of the gases passing loweriues may be reduced or the introducthese iues may be dis- .continued entirely. `As the operation progresses, the heatingzone may thus be eX- tended upwards and its upper limit is maintained at a level'in proximityv to the level of the added increments of pitch Abeing coked.

Its lower limit may eventually be moved upwards when the lower part of the charge is completely` coked.

The amount of pitch added at each interval may be varied as desirable. Each added increment may measure a fraction of an inch on the vertical walls of the oven or as much as several inches of pitch may be added at one time. When a considerable amount of pitch is added to the oven at one time, the material inthe oven is advantageously coked to the point where it produces a solid inass before additional pitch is added. 1Whenthe increments are small, the coking need not proceed as far before additional fresh pitch is added to the oven.

'In thus converting pitch to coke, oils are distilled from the coking mass and gaseous constituents are evolved which are valuable as fuel. The gases and vapors which are given olf by the coking mass are advantageously collected and cooled to separate the oils which will include oils of higher boiling range and greasy and r'esinous constituents, and the fixed gases inay be collected in a gas holder for use as fuel. When several-ovens are operated simultaneously the gases may advantageously be collectedlin a gas collector main similar Ato that employed in connection with a battery of coke ovens, and the com- 5 bined gases passed from the collector `main to a condensing system, not shown.

When cllean oil products are desired, the

gases may advantageously be cleaned while at a high temperature either in an electrical precipitator or in a suitable hot pitch scrubber so that on cooling the hot cleaned gases clean oils will be recovered directly from the gases.

After the pitch is coked, it is reinovedlfrom `the oven in any suitable manner, as for eX ample, by pushing-the coke with a pusher similar to that employed for the removal of coke from coke ovens. The coke obtained isa solid compact coke of low ashcontent. It is suitable for' metallurgical processes and through the l one regenerator,

sired. It is readily obtained in large pieces Iand by careful handling and classification only a limited amount 4of nes will be produced.

The invention will be further described in connection with the accompanying drawings, which show adjacent ovens of a battery at different stages of the coking operation.

Fig. 1 is a vertical section through a battery `of ovens; and

Fig. 2 is a section on the line2-2 of Fig. 1.

The drawings show live ovens, A, B, C, D, and E.- The height of each oven chamber is relatively greater than the width and so also is the height of the final coke bed produced in each oven greater than its width. Pitch is supplied to the ovensthrough pipes 21 inserted through the charging holes 22. An uptake pipe 23- is provided for removing gases and vapors evolved during the coking of the coal. The gases and vapors are conduct-ed to a condensing system (not shown) for the recovery of tar products. The drawing shows heating iues, 1a, 2a, 3a 6a, 1b' 6e embedded in the side walls of each of the ovens. The lowermost fines are indicated at 1a, 1b, etc. the intermediate flues are shown at 2a, 3a, 4a, 5a. 2b, etc.; lues are shown ata, 6b, etc. lues in the wall of each ovenmay be varied as desired, and lues common to two adjacent ovens may be employed, or separate flues for each oven-y may be employed, as shown in the drawings.

Below the ovens are regenerator chambers 10. The regenerators are operated in pairs andare provided with valves (not shown) of the usual type'so that after the hot waste combustion gases have heated the brick 11 in and the air for combustion has cooled the brick in a. second regenerator.

The number 'of and the top f the hot waste combustion gases .are passed a through this second regenerator. reheating it,

and the air for the combustion is passed over the hot bricl inthe first regenerator, .theair being thus prehead. After suiiicient time 'through the wall between adjacent `ovens and `connects with the second regenerator. When the-How of air and gases is up through the lues, as'indicated by the arrows in the drawings,'preheated air from the regenerator en# ters at 12. The amount of air admittedis regulated by proper valve means, such 'as a v brick which partially covers one of the ues,

and the amount of air is adjusted to provide that necessary for combustion at those burners which are lighted. The hot Waste combustion gases escape through the iue 13 to a regenerator which they heat. When the flow of air and gases is reversed, air which has been preheated by passage through the last mentioned regenerator enters at 13 and, after passing down through the flues and ei'ecting the desired combustion, is exhausted through the flue 12 to the regenerator.

of the coking operation the fines at the bottom of .the oven are raised to intense heat by burners in these bottom fines and as pitch is added to the ovens and the level of the pitch in the ovens rises. the zone of intense heating is raised. by lighting burners in higher fines. As the pitch is coked` the burners Which-heat that portion ot the Voven in which coke has formed may be extinguished. The coking operation may be so controlled, for example, that pitch in the bottom of the oven heated bv the burners 16 Willbe coked before pitch is added to the upper portion of the oven heated by the burners 17. and the burners 16 may be extinguished after the burners 18. 19 and 20 have been lighted in succession and before the last portion of the charge of pitch has been added tothe oven and before` the burners 17 are lighted.

When the preheated air and. gas iow Aupv through the fines. as indicatedby the arrows in the drawings. the flame'fr'o'fn each of the burners will heat the upper. of the two fines at the junction of which-each bnrner is lo-l cated. The flame from the burner 16, for example, will be in the flue 2. When the flow of air and gases is' reversed', the flame from' the burner 16 will be in the Hue 1 and will heat this line. When both the burners 16 and 18 areignited, the flame from one of these burners willheat the fine 2 at all times and the liues 1 and 3 will be directly heated dur-` ing only one-half of the time. In the same manner the ames from the Aburners 19. 20 and 17 will heat the lues 3, 4, 5 and 6 when these burners are ignited. The waste combustion gases passing through-the fines will keep the Walls of theoven atan elevated temperature at all times, and only selected portlions of thewalls .will be raised to intense eat.

VThe pitchplmay be added to the oven gradually and continually during the coking op-` eration'until'the desired charge has been added to the ovens. 'as'v a 'continuou'sstreamL' As an alternative method small-increments of pitch may be added to the ovensI from time'to time. Each 'increment may represent'but an inch or ItWo of pitch over the entire areav of' the oven. On the other hand, the entire charge of pitch may be charged to the oven in three or four charges, with a lapse of two or three hours between charges. All of the charges may be uniform or it may be advantageous to vary the size of the charge as the coking operation progressesl The pitch may be added The drawings indicate an operation in i which several ovens of a battery are charged in rotation and in which high meltingjpoint pitch is charged to'each oven in four separate portions. .Eachl oven indicates a different stage of the coking operation. The

.burners 16 of the .ovenA are lighted and the fines 1a and' 2a are heated. Burners 18 are then lighted, lines 2a are brought to an' I intense heat as indicated in the drawings,

and lines 1a and 3a are heated, and the first charge is added to the oven.v

After about two hours, burners 19 are ignited as indicatedat oven-B, and flues 2b and 8b are brought to intense heat and the second portion of the charge isxadded to the oven. Then burners 20 are lighted, the third portion of the charge is added to -the oven v as shown at oven C, and iues 40 are brought to lntense heat.V

The fourth portion of the charge may be :i0:

somewhat smaller than previous charges in order to prevent the oven from foaming over. v The drawings show, oven D after the `fourth charge is added and With flues 5d brought to an intenseheat 4by the burn'ersl. When the coling is so controlled that' the ir'st portion ofthe charge is completely coked. by`

the time this :fourth-'portion is added to the oven, burners 16 may be extinguished since fines 2d need no longer be maintained at intenseI heat. Flnes 1d Will then only be heated by the Waste combustion gases which pass through them in going to flue 14 and the regenerator. A

As the coking proceeds burners 18 may be extinguished. Then only flues 4e and 5e will be at intense'heat as shown at oven- E. Vhen the coking is inallycompletedgthe burners may allbe extinguished, or the gas iow through them greatly reduced, and the charge of coke maybe pushed from the .the oven, or removed vin any sutableWay.

Before pushing, burners 16, or' both burners 16 and 18, may be lighted sothat When the oven is pushed the bottom of theoven will be hot and ready for charging. lThe oven is tinguish only the upper burners when they are no longer needed for heating.

The drawings are merely illustrative as to the number of ovens which maybe employed in series, the type of coking vessel that may -be used, and as to the manner ot supplying the pitch to the ovens.` The time necessary for coking a ull charge of pitch or a partial charge is dependent upon the size of the oven, the nature of the heating lues, the melting point and volatile content of the pitch, etc.

I claim:

l. The method of coking a batch ot pitch, which comprises gradually adding the pitch to a coking vessel, heating'it indirectly so as to coke it, maintaining the pitch and the coke substantially stationary during the cokingl operation and as the mass of coke formed: increases by the addition of pitch and its conversion to coke, changing the zone to which heat is applied so that the most intense heat' is applied to the added material which has not formed coke so as to convert it to coke.

2. The method of coking a batch of pitch, which comprises gradually adding the pitch' to a coking vessel, heating it indirectly so as to coke it, maintaining the pitch and-the coke substantially stationary during the coking operation and as the mass of coke formed increases by the addition of pitch and its conversion to coke, changing the Zone to which heat is applied so that the most intense heat is applied to the added material which has not formed coke in order to convert it to coke, and cooling the gases and vapors thus produced to recover oils therefrom.

3. The method of coking pitch in a coke; oven, which comprises gradually adding pitch to a substantially stationary mass of pitch in the oven while coking the mass, and extending the zone of intense heating of the walls of the oven from the bottom upwardly as the coking layer of the 'mass rises in the oven.

4. The method of coking pitch, which comprises heating the bottom portion of a cohef oven, gradually'adding .pitch thereto, maintaining the added pitch substantially sta-- tionary and converting it to coke, and continuing to.' add pitch gradually to the oven and to build up a mass of coke in the' oven, and

extending the zone of intense heating of the walls of the oven from the bottom upwardly as the level of the pitch being coked rises within the oven.

5. The method of coking pitch, which comprises adding a small amount of pitch to an oven and applying heat to the sole of the ove'n whereby a substantially stationary coking cent to material which is being coked. I

batch of mass is formed, adding increments of pitch to the oven at intervals while coking the substantially stationary coking mass, and as the level of the pitch vbeing coked rises within the oven, extending the zone-of intense heating of the wallsof the oven from the bottom up,- wardly. f

' 6. 'lhe inethodgof coking a batch of pitch, which comprises gradually adding the pitch to an oven while heating the oven indirectly whereby a substantially stationary coking mass is formed, and the stationary mass is converted to coke,- and applying the greatest' heat to the oven in a zone adjacent to pitch which is being converted to coke.

7. The method of converting pitch to coke, which comprises gradually adding pitch to an oven, maintainingthe added pitch sub- Y f i' stantially stationary, applying heatto the oven so as to convert the pitch in the oven to coke While continuously adding pitch to the oven, and as pitch isadded and convertedto coke changing the zone to which the most intense heat is applied so that the -most intense heat is applied to the walls ofthe oven adja- 8. Themethod of converting ap'itch to coke, which comprises coking the pitch in an oven by applying heatto the bottom of the oven, addin g increments of the pitch to the oven at intervals as the material in the loven is cokedwhile Vheating the oven.,- 1 maintaining .the pitch and the coke substantially stationary during theA coking operation, and changing the zone of greatest heat as thevoven lbecomes filled with pitch and. coke so that the greatest heat is applied to the oven above thel coke which has been formed in the ovenand adjacent to the material being coked.

9. The meth d of converting pitch to coke,

los

which comprises gradually adding pitch to an oven while 'converting'the pitch inthe oven to coke, maintaining the pitch and the coke substantially stationary during the coking operation, heating only lower portions of the oven during the early portion of the coking operation as -pitch'is being added to the oven, heating the upper portion of the oven4 to an intense heaty as the last of the pitch is added to the oven, and maintaining Vthe upper portion'of the oven at an intense heatuntil the cokingis completed.

10. 'The steps in the method of converting pitch tocoke, which comprise adding pitch to an ovencontaining coke newly formed from pitch and applyingheat through the Walls of the oven adjacent to the added pitch so as to convert the pitch t o coke, subsequently decreasing theappl-ication of heat to that portion of the walls of the oven adjacent to this newly formed coke While applying intense heat to another portion of the walls of the oven adjacent to pitch added to the oven while the aforementioned pitch was being 10 the co AARTHUR H. RADASCH.

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