US2065288A - Process of coking coal - Google Patents

Description

Dec. 22, 1936; c. one I 2,065,288

PROCESS OF COKING COAL Filed July 1, 1951 3 Sheets-Sheet 1 Fig. 1

INVENTOR- ATTORN EY 3 Sheets-Sheet 2 'C. OTTO PROCESS OF COKING COAL Filed July 1, 1951 Dec. 22, 1936.

INVENTOR Di in 1 ll/WI? Dec. 22, 1936. c OTTO 2,065,288

PROCESS OF GOKING COAL Filed .July 1, 1931 3 Sheets-Sheet 3 Fig.1 4

INVENTOR Ca -6% ATTORN EY Patented use. we Y UNlTED STATES messes raoosss or come cost; Carl magnum-nun, Germany Application July 1, 19 i i InGermany :1, sun] No.- 548.201 my 1, 19:0

10mm (01. soc-st) The invention has ior its object a coking process tobe carried into eflect in intermittently operatingcoking chambers in which process at the beginning of the. coking Period the 5 gases produced. are sucked out oi the interior of the charge in .such a manner that, in addition to a considerably increased yield of light oil and primary tar an improvement of the -qual-- ity of. the coke 'is attalned more particularlywith coal sorts which have only little tendency .to baking. 'With these ends in View, the suction of the 'gasesof distillation produced at thev beginning of the coking period irom the interior of the charge is carried through in such a manner that formation of a-coking seam is avoided or that such formation .at least occurs to a very smaller extent than hitherto. The measures taken for this purpose and described hereinafter are based on the hypothesis that the coking seam is due to deposition of vaporous products oi distillation on coal particles which are cooler than the products.

According. to the invention this condensation and deposition of products 01' distillation is avoided by either notably increasing the velocity 4 of the escaping products of distillation or increasing their temperature beyond their point a seam already formed upon the escapement oi the-distillation gases, according to the invention the distillation gases are drawn on! from the coking chambers,.the charge. of which is still,

inth'e ilrststage of the coking period, by'means of pipes projecting intoi-the charge' and under.

so high a above atmospheric that'n'o higher pressures in the upper gas coilecting spaces oi-thewhambers than inthe' 5 adjacent heating walls.,.i 'lhe pressures required .ror this me s in with'the results.

' or the amount toatleastzoo min. water. but are Furthermore, as with-pressures "of this height ine-mus existing between the heating ilues made of silica brickwork areno longer-gas-tight, and care hasto be takenthat no substantially lower pressure prevails in chambers in the 55 vicinity of these walls than in the adiacent heattlally eliminate the noxiouseifectot .a coking.

. these coking chambers are supplied together with 4 6 oil the distillation-gasesiromlthe chamber. In and the chambers. which are normally ing'fiues." Hence, in practice it is to provide a regulating device by which the power of the gas suctionis regulated in such a.-manner, for instance by means of a valve inserted in the suction conduit, that in the vicinity of 5 the chamber side 01! the walls that separate the coking chambers from the heating flues ;neither a notably higher. nor a notably'lower pressure will prevail than-on the ,side of the heating flues. This regulating-device is actuated suitably'in a manner as to r spond to the difierence of. pressure existing between the upper gas collecting spaces oi. the cokingicharhbers "and the neighboring- Such a. regulating device is requiredparticularly because the resistance the'cake oilers to the gases passing therethrough considerably varies during a the coking period. 7

- A. further possibility of avoiding formation oi a coking seam or to notably reduce its disad-. vantageous eilect may consist in introducing into the chambers a hot gas which together with the products of distillation generated is sucked oil through the above pipes which project into the charge, this mixture of. introduced and distillation. gas then having such temperature that ithas no tendency to condense even when pass.- ing through cooler coal =0! the charge.

Furthermore, instead oi introducing superheated steam. hot water'gas' is also well 3 to realize this portion oi the invention, and more particularly even water gas the carbon of which hasnotyetbeenlargeiyreduc'ed. 'lhewater gas may be supplied'either by'a'special producer or better from cokingchambers-oi the same battery in-which the charge has already completely.burned oil and wherein the water 8 s Droducedby blowing in steam. In way also the hot distillatiomgases producedin the water-gas thus. produced; therein to the battery lnwhich the charge in the first l'tagefilthe cokingor vapors are-supplied either through'the uppergas collecting of the chamber or better pipes which likewise project intothe charge have openingswhich pipes maybe designed like those serving to draw thismanner oi-operation' two seals may be made useot, the one oi-whichthroush pixies nroiectmg into the charge draws oil distillation gases from. the chambers the or which isain the ilrst stage cl the coking pgridlli while other 55 or auxiliary seal merely serves to establish a communication between the upper gas collecting spaces of the chambers the charge of which is in the last coking stage and the members that feed these hot gases to the chambers the charge of which is still in the first coking stage.

The suction of the distillation gases as well as the supply of the hot scavenging gases may be effected by known horizontal or vertical pipes. During the last stage of the coking period the suction pipes may also serve for the introduction of steam into the chambers for the generation of the water gas. If vertical suction pipes are to be provided for, these pipes may be introduced into the chamber through apertures that can be completely gas-tightly shut off. These apertures are provided in series in the oven cover in the central plane of the chamber between the charging holes. After the chamber has been filled suitable rods are pushed down into the fresh charge by which rods passages are prepared for the pipes and which preferably are mounted on the larry car of the battery and manipulated from the latter, the whole system of pushing rods and their actuating mechanism advantageously being designed so as to be rocked or lifted into an inoperative position in order to permit easy travel of the larry car. As a matter of course, however, the pushing rods together with an actuating mechanism hereinafter described may be mounted on ajspecial car travelling on the track of the larrm car.

After vertical passages have been formed in the charge by the aid of the above pushing rods, the suctiorifpipes are lowered into these passages so as to .ptoiect partly thereinto. In order to attain me..- 0st uniform possible suction in the verticaldirection, the vertical suction pipes may have different lengths so as to project into the charge to diiferent depths.

Furthermore, in order to attain a. close contact'of the coal with the suction pipes, the latter may be introduced into the charge together with the pushing rods. After this introduction the rods are removed while the suction pipes remain in the charge.

The connection of the suction pipes of each chamber with the common high quality gas seal is advantageously established by providing fixed conduits on the apertures of the oven cover which conduits lead to a main above each chamber serving to draw of! the whole distillation gases of a chamber and are connected to the primary tar seal, a valve being provided in each of these conduits. These mains may also be connected to the conduit that feeds superheated steam, so that when going over from the suction of primary tar to introduction of steam, only reversal of the valve is required, whilst the apertures in the oven cover can remain closed and gas tight.

In order that the heavy hydrocarbons drawn of! during the first stage of the coking period are not exposed to cracking, the temperature in all the conduits must not exceed a determined degree, and the suction means are therefore cooled.

Inorder to cool the suction device cooling members may be provided in the suction pipes. Thwe cooling members preferably consist in porous cylinders of ordinary or fire clay to which water is fed dropwise in regulatable quantities. The water then evaporates on the large surface of the cylinders to which thus can be given an exactly determined temperature so that the suction pipes can be kept cool in any desired degree. The pipes must of course not become too cold as otherwise the high boiling hydrocarbons would condense and return to the coking chamber.

In order that the invention may be clearly understood and readily carried into effect, an embodiment of the same is illustrated by way of example in the accompanying drawings in connection with a chamber oven adapted for the realization of the process according to the invention.

Figure 1 is a vertical sectional view thru the 7 top of a coking chamber.

Figure 2 is a vertical section thru the top of a chamber showing a form of carrying car for the pusher rods.

Figure 3 is a sectional view through a coking chamber, showing another form of means for carrying out the invention.

Figure 4 is a front view of the chamber shown in Figure 3.

Referring first to Figure 1 which is a view of the top portion of a coking chamber, I denotes a coking chamber and la the coal charge to be coked in the chamber. The chamber is closed by the usual doors 2. Vertical passages 3 in the charge thru which the distillation gases are drawn off during the first stage of the coking period and thru which steam may be later introduced. The larry car 5 travels on the track 4 and through the hoppers 6 of the car coal is supplied to the chamber through the charging holes 1. After opening the closures 8, the pushing rods 23 (shown in Figure 2), are introduced through the apertures ll provided in the top of the oven. The pushing rods prepare the above passages 3 in the coal charge. After removal of the rods or also directly with their introduction the pipes 9 are suspended from the apertures H which pipes are arranged in a row in the longitudinal direction of the chamber and serve first to draw off the distillation gases and later on to supply steam. Within the pipes 9 are mounted the above-described cooling members ID. The apertures II which enlarge in upward direction, are connected by pipes ii to a collecting main 13 which according to the position of the valves ll and I5 is in communication either with the seal I! or with the steam collecting conduit II. The valve i4 is automatically controlled in a manner not shown by a controlling mechanism operating in response to the difference of pressure and communicating both with the gas collecting space I! of a chamber and one of the adjacent heating walls of the said coking chamber.

The gas collecting spaces I! of all the chambers of a battery are interconnected by a conduit l6 running within the oven cover in the longitudinal direction of the battery which con- I duit normally is closed by plugs It. By means of valves (not shown) the conduit Ii can be shut oi! fromall but one of the gas collecting spaces It. These other spaces It have to be shut 0153 especially when their doors 2 are to be removed in order to push the respective charge. The conduit It serves to supp y steam after it has been introduced according to the invention thru the pipes 9 during the last stage of the coking period, or a mixture of steam, water gas and distillation gas, to the chambers in which the charge is still in the first coking stage, whereby an accelerated expulsion of the'heavy hydrocarbons is attained. The distillation gases developed during the last coking stage are thus drawn ofl? immediately from'every chamber into main [6 andarrive in the seal l9 only by passing. through the collecting main l6 and through those chambers the charge of which is still in the first coking stage. By suitably governing the coking process and the provision of a powerful suction in the individual chambers no formation of any coking seam at all occurs, as hitherto, that is the coking seam hitherto formed in the vertical central plane of the charge does not appear. On the contrary, solid coke blocks extending from the one chamber wall to the other are formed. In this way the possibility is given of production of large coke also in very narrow coking chambers; and of a considerable reduction of the duration of the coking period. Furthermore, because of the fact-that by the introduction of steam partial cooling of the charge is attained within the chamber, a smaller quantity of heat is lost by the coke later on .being quenched; the heat economy of an oven plant designed according to the invention thus being better than hitherto. Finally, this cooling of the coke within the chamber further favors the formation of large coke blocks, as it has been observed that a coke that already has been cooled partly within the chamber forms larger pieces than a coke which is pushed when still in a very hot state.

In Figure 2 isillustrated by a view of a suitable embodiment of a car carrying the system of pushing rods and appurtenant actuating mechanisms.

The illustrated car 20 travels on the track 4 of the larry car of the battery. 23 denotes the pushingrods which are vertically movably arrangedin guide tubes 23. These tubes have longitudinal slots through which project lugs 2| 'flxedon the respective pushing rods 23 and serving for the attachment of an endless actuating cable or chain 2| which runs on suitable pulleys or sprocket wheels 22, 22'. The pulleys are driven by a motor (not shown) mounted on the car 20. In this way the rods 23 are pushed into the charge or lifted therefrom.

The improvement of the quality of the tar as aimed at by the invention" as well as the increased yield of tar and light oil is warranted only if the weakening of the coal is not accompanied' by a quick increase of temperature so .5 that the heavy hydrocarbons generated are not "55 exposed to high temperatures. In connection with a slow increase of temperature the invention further provides that. the resistance offered to' the distillation gases by a coking seam which maybe is formed remains small. To this .end

according to the invention the heating of the coking chambers is regulated in such a manner that during the distillation when gases are sucked oil from the midst of the coke cake.

all portions of the charge, including those situ- C. usual in the high temperature coking process,v

whilst much lower temperatures prevailed in the midst of the cake. According to the invention the temperature of the portions of the charge in the vicinity of the heating walls is maintained below 700 C. until the coal has gone over throughout'toplastic state and as long as the distillation gas is still being sucked off from the midst of the coal cake.

- The means to be provided for maintaining the temperature of all portions of the charge below 700 C. may be of various nature. It is obvious so to heat the'heating walls that only little gas is fed during the first hours of the coking period. For this manner of operation, however, it is necessary that the two coking chambers beside a heating wall are emptied and re-filled only in short intervals or that each heating wall is subdivided into two parallel rows of heating flues. It is possible, however, to maintain a uniform heating and to attain nevertheless the desired low temperature of the coal portions situated near the heating wall by properiod may take place through. horizontal or vertical pipes in lieu of through the upper gas ,collecting space, which pipes project into the charge.

The Figures 3 and 4 show embodiments of this type; Figure 3 being a fragmentary view through a coking chamber, while in Figure is the corresponding front view. 'Ihe'upper gas collecting spaces of the chambers which are in the last coking stage can be connected with an auxiliary seal from which the hot distillation gases or a mixture of distillation gas, steam and water gas can be supplied to the chambers which are in the first coking stage by special pipes projecting into the charge.

In additionto the seal 24 which by a vertical pipe 25 and a bent pipe 26 is connected to the upper gas collecting spaces of the chambers of a battery and'can be shut oi! therefrom, and to the collecting pipes 2I which likewise can be shut off by valves 28, an auxiliary seal 29 is to vertical pipes II extending between the chemher doors which pipes can be shut oil by valves 32. Horizontal pipes provided with perforations may be introduced through the chamber doors 33 which pipes, according to whether they are to serve for sucking of! the distillation gases or for supplying the hot steam-water gas mixture,

are connected with either the ascension pipes 21 or 3|, by means of the bent pipes 34.

All or part of the horizontal pipes may be connected to steam collecting conduits (not shown) after the coking process has already made progress, while the ascension pipes 25 remain shut of! during the entire coking period. P In thiscase the distillation gases are drawn oi! from the battery merely through those of the horizontal pipes which through. the ascension pipes 21- are in connection with the hydraulic main 24. while from those chambers to which steam is' fed through the horizontal pipes the mixture of distillation gas, steam and water gas arrives through the upper gas-collecting space in the auxiliary main 29 from where itis fed through the ascension pipes 3| and the horizontal pipes-attached thereto to the coking chambers the charge of which is in the first stage of the coking period, where it acts as scavenging gas and prevents condensation of constituents of the distillation gas and their deposition onto the coal particles and thus formation of a coking seam.

In Figure 3 only three horizontal pipes one above the other are shown, it will, however, be

of advantage to provide a greater number of such pipes in order to attain a more uniform penetration of the charge of the' hot scavenging gases and a more effective suction of the distillation gases, the mutual distance of the pipes in a vertical direction then being not greater than about half of or the whole width of the chamber.

Should horizontal pipes be used, it is advantageous to alternately dispose between two neighboring chamber doors the ascension pipes serving to draw oil the distillation gases and those serving for the supply of the scavenging gases, as illustrated in Figures 3 and a.

What is claimed is:

1. The batch process of coking coal in a coking chamber provided with heating walls which comprises charging the chamber with coal, providing passages in said charge leading to the interior thereof, externally heating the charge thereby carbonizing the coal, drawing off distillation gases by, suction from the interior of the charge thru said passages during the first coking period, and introducing scavenging gas into said chamber during the first coking period, the temperature of said gases being more than 500 centigrade.

2. The batch process of coking coal in coking chambers provided with heating walls, which comprises charging the chambers with coal, providing passages in each charge leading to the interior thereof, externally heating the charge thereby carbonizing the coal. drawing on the distillation gases by suction from the interior of each charge thru said passages during the first coking period, and drawing off the gases from chambers during the last coking period and supplying said gases to other chambers in which the charge is in the first coking period.

3. The batch process of coking coal in a coking chamber provided with heating walls, which comprises charging the chamber with coal, providing passages in said charge leading to the interior thereof, externally heating the charge thereby carbonizing the coal, supplying gas to the chamber during the first stage of the coking period therein at a temperature in excess of 500 C., drawing oif distillation and supplied gases during the first stage of the coking period from the interior of the charge by suction, and admitting steam to said charge during a later stage of the coking.

4. The batch process of coking coal'in coking chambers provided with heating walls which comprises, charging the chambers with coal, providing passages in each charge leading to the interior thereof, externally heating the charge thereby carbonizing the coal, drawing ofl. distillation gases from the interior of the charge of at least one chamber by suction during the first stage of the coking period, admitting steam to said chamber during a later stage of the coking period thereof, drawing oif the distillation gases and water gas generated in the chamber in" said later stage, and supplying the gases so generated to another chamber in which the charge is in the first stage of the coking period.

accuses 5. The batch process of coking coal in coking chambers provided with heating walls, which comprises charging the chambers with coal successively, providing passages in the charge in each chamber leading to the interior thereof, externally heating each charge thereby carbonizing the coal, supplying gas to each chamber during the first coking period of the charge therein, drawing off the distillation and supplied gas from each chamber by suction during the first coking period of the charge therein, introducing steam into the said passages of the charge in each chamber during a later coking period of the charge therein, and withdrawing the gas formed in each chamber during said later coking period, and utilizing the gas withdrawn from chambers during the later coking periods therein as the gas supplied to chambers in which the first charge coking periods are then occurring.

6. A batch process of coking coal in a horizontal coking retort oven structure comprising a plurality of coking chambers and heating walls alternating therewith and formed with openings in the top wall of each chamber distributed along the length of the latter, and with horizontal channels in the upper portion of said structure extending longitudinally of the chambers and individually adjacent to and communicating with the top wall openings of one of said chambers, and formed with a horizontal passage in the upper portion of the structure extending transversely of said chambers and communicating with each chamber at its top, which process comprises successively charging the different chambers with coal so that the coking operations in the different chambers may begin and end at difierent times, and so as to leave a gas space at the top of each chamber above the charge therein, providing vertical passages in the charge in each oven, one beneath each of the openings in the top wall thereof, connecting each of the top wall openings of each chamber with the subjacent passage by a conduit traversing the said gas space in the chamber, externally heating the charge in each chamber thereby carbonizing the coal therein, drawing off distillation gases by suction from the interior of the charge in each chamber during the first coking period therein, through the passages in the last mentioned charge and the communicating conduits, openings, and channel, and during the final. coking period in each chamber, supplying superheated steam to the charge therein through the said passages in the charge and the communicating conduits, openings, and channel, and regulating the pressures in the gas spaces in the different chambers so as to createa gas flow between the latter through said horizontal passage into and out of each chamber during the flrst and final coking periods therein, respectively.

7. A process of coking coal in a horizontal coking retort oven structure comprising a plurality of coking chambers and heating walls alternating therewith, which consists in charging the different chambers at different intervals and so as to leave a gas space above the charge and coking the charges therein in approximately the same coking time so that at any one time the coking operations in diiferent chambers are in different stages, withdrawing the distillation gases from each retort during an early stage of the coking operation therein by applying suction to the interior of the charge therein and thereby creating a gas flow to the interior of 76 aooaaas.

from the said spaces in retorts in which the coking operations are in later stages without significant change in gas pressure into the said spaces of the retorts in which distillation gases are being withdrawn from the interiors of the charges as aforesaid, whereby the gas pressures at the surfaces of the charges in the different retorts are equalized and the gases passed into retorts in which the coking operations are in their early stage, serve in the last mentioned retorts as scavenging gases drawn into the charges from thesurfaces of the latter.

CARL OTTO.

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