US2119176A - Apparatus for coking coal - Google Patents

Description

May 31, 1938.

A. OGG

APPARATUS FOR COKINGY COAL Filed June 13, 1955 4 Sheets-Sheet l 4 Sheets-Sheet 2 W. A. OGG

'Filed June 13 1935 APPARATUS FOR COKING COAL May 3l, 1938.

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HMMVM-Mf//Kw Patented May 31, 1938 UNITED STATES PATENT OFFiCE 16 claims.

This invention relates to the coking of coal and the object is to provide an apparatus for this purpose whereby rapid coking is effectedunder conditions of high thermal efficiency at small `capital and operating cost. I

My invention will be well understood by reference to the following description of the illustrative embodiment thereof shown by way of example in the accompanying drawings, wherein:-

Fig. 1 is a longitudinal section through the furnace or oven;

Fig. 2 is a plan in section;

Fig. 3 is a partial transverse section on line 3-3 of Fig. 2;

Fig. 4 is a fragmentary section on an enlarged scale on line 4 4 of Fig. 2;

Figs. 5 and 6 are respectively a side elevation and a plan of a container;

Fig. 7 is a section on the line T--l of Fig. 5;

Figs.8 and 9 are respectively a side elevation and plan of a modified form of container; and

Fig. 10 is a section on the line IU-l of Fig. 8.

In the customary practice of coking coal at the present time large and elaborate ovens are utilized having retorts defined by walls of substantial structural strength in which are provided flues for the heating gases. To provide the necessary structural strength and provide walls sufficiently strong towithstand the pressure of the coal and also to withstand the strains caused by the ram which pushes the cokeout of the oven, these walls are as a minimum about four inches thick and in parts considerably thicker than that. In mod` ern practice these retort walls are almost invariably rnade of silica brick as this has a somewhat higher thermal conductivity than ordinary firebrick and can withstand high heats in the flue. On the other hand, silica is a very fragile brick. Suggestions have been made to utilize refrac- 40 tories of higher heat conductivity such as those consisting essentially of silicon carbide, buton account of their fragility and their tendency to increase in area as time goes on this has not proved practical. Consequently the rate of heat 45 conduction and the thermal efficiency of these ovens is relatively low. In many processes of distillation the material to be distilled is Vplaced in containers but for high temperature coking such an arrangement has not hitherto been con- 50 sidered because the containers available would not withstand the heat involved and because of the difficulty in charging and discharging. The apparatus which I am about to describe as an eX- ample of my invention bears a superficial resem- 55 blance to some of the suggestions previously made in that I provide for coking the coal in containers and utilize approved refractories, but the combination more fully to be described eliminates the disadvantages of prior processes and provides an economic and technologie efficiency. 5

Referring to the drawings, I have there shown an oven having a general closure embodying end walls l2, side walls I4 and a roof it of suitable masonry construction and which herein is provided with a central wall I1 forming two dupli- 10 cate sections, such construction not being in any way essential to the invention. It will herein be necessary to refer to but a single one of these sections. Thercentral portion of this enclosure provides for the reaction chambers and gas oifl5 takes I3 for the products of distillation are provided in the roof I6, as shown in Fig. 1. Referring to Fig. 1, the bottoms of the reaction charnbers are defined by the sole 20 of the furnace, herein shown as built above the regenerative 20 chambers 22. On this sole, as best seen in Figs. 2 and 3, are built longitudinal walls 24 defining between them long, tunnel-like, reaction chambers or ovens. The walls 24 are constructed of hollow shapes of material highly resistant to heat and 25 of high heat conductivity consisting essentially of silicon carbide or its equivalent. Such material is well known under the commercial name "Carbofrax and for convenience I will hereinafter in this specification use that name. These shapes 30 may be of a generally rectangular, tubular form and are connected together to define the longitudinally extending heating flues 26, best seen in Fig. 3, four of them being there shown, which open at the ends of the wall to upright header-like passages 28 (Fig. 2) which communicate through the openings 29 with the regenerative chambers 22. It will be understood that fuel may be burned adjacent the headers 28 to supply` heating gases to the flues to radiate heat through the walls thereof into the reaction chambers and that the direction of flow of the gases may be reversed from time to time in the usual manner.

To carry out the aims of my invention the walls of the refractory shapes are thin and in practice I have found that Carbofrax iiues with walls one inch in thickness are satisfactory, this being made possible because the walls carry no structural load and are not subjected to any strain from the coal being treated or from handling mechanism for moving coal. The bottom or lowest flue is here cemented to the sole 20 of the furnace and the other heating flues set on top thereof and joined together, but except for the sole the flue walls have lno connection with the other walls of the furnace and may expand and contract or, as the use of the furnace continues, grow in the manner characteristic of the material without setting up disrupting strains. Otherwise described, it might be said that the flue-containing walls 24 are of a free floating nature. By virtue of the arrangement and light construction of the walls the use of Carbofrax is rendered possible and a high thermal efliciency made possible. The walls may heat up rapidly and, if necessary, the oven can be shut down quickly without danger.

The coal to be coked is positioned within the r-eaction chamber between the walls thereof in tall, long and narrow containers 32 having a substantial clearance from the heat-radiating walls, two being here shown for each reaction chamber. These containers, as shown in detail, for example, in Figs. 5, 6 and 7, have extended side walls, restricted, narrow end walls and open tops and bottoms through which respectively the coal to be colred may be supplied and the nished coke may be discharged. Preferably, as shown in Fig. 7, the container may fiare downwardly slightly to facilitate discharge. During the coking reaction the containers rest, as shown in Fig. 1, on the sole 25 of the reaction chamber which sustains the weight of the charge. As a suitable dimension for the containers to indicate in a general way but without exact limitation what I refer to as narrow I may say that a width of about a foot has proven satisfactory whereas the length and width are much greater to provide for handling a substantial body of coal. To permit the containers to withstand the high heats involved they are constructed essentially of Carbofrax and in Figs. 5, 6 and 7 they are illustrated as being formed of a number of tiles 34 of this material, say about an inch in thickness, which are set in a framework 36 of suitable shapes of chrome-nickel-steel. In Figs. S, 9 and 10 a modifled construction is shown consisting of a number of tubular members 38 of Carbofrax, three being illustrated in Fig. 9, hooped about and held together by bands fl of chrome-nickel-steel. It will be understood that these containers need not necessarily be gas-tight since, if there are slight cracks in the side, the only result will be that some of the distilled gases may escape therefrom and find their way to the upper part of the oven and to the gas outlets I8. The containers, however, should retain their form under the high heats to which they are subjected as a distortion or warping such as would take place with a metal container would render the discharge of the coke impossible or require such ramming or scraping as would tend to destroy the containers. The construction described when utilized in the manner herein set forth involving no handling and the heating of the material by radiant heat on the walls of the containers provides for this.

With the containers loaded and in position in the manner shown in Fig. 1, heat may be supplied to the fluesr26 and may be transmitted efciently through their thin walls of high heatconducting capacity and thence will be radiated through the narrow clearance space onto the highly heat-conducting walls of the containers and thence to the charge of coal therein, through which it apparently is transmitted to a considerable degree byy convection currents. High thermal efficiency is thus provided for which permits very rapid coking, the coking operation proceeding through the body of coal at a rate much exc-eeding that now common.

In the embodiment of my invention herein shown the coal is coked on a batch system. That is, the containers are not moved during coking and the entire set or series of containers for each reaction chamber is contained therein for treatment throughout the same period although it will be understood that my invention is not necessarily limited to such a construction. In the present instance there are provided, antechambers 42 within the general enclosure of the oven and at the ends of the reaction chambers. Herein each reaction chamber is adapted to accommodate two containers 32 suitably coupled together and chains 44 of heat-resisting material such as chrome-nickel-steel may be attached to clevises 116 (Fig. 5) anchored to the frame members 36 of the container and be wound on drum shafts 48 adapted to be rotated by the electric motors 55 (Fig. 2). The set of containers, as shown in Fig. 1, may thus be drawn, for example, to the left to dispose the left-hand container in the loft-hand ante-chamber to permit the charge of finished coke to be dumped therefrom and the container relled, and then it may be drawn to the right to permit similar discharge and recharging of the right-hand container in the righthand ante-chamber. The two containers may then be retracted to the left to the position of Fig. l for another operation.

To provide for discharge of the finished coke the ante-chamber, as best seen in Figs. 2 and 4, is provided with longitudinal supports 52 at a level of the sole 2U of the furnace on which the side walls of the containers 32 are adapted to move, these supports 52 defining between them openings 54 with which the open bottoms of the containers register when the containers are withdrawn into the ante-chambers and through which they may discharge to the hoppers 56 (Fig. 1). To provide for reloading the container suitable closures are provided for these openings. Moreover, since the coke shrinks I prefer to support it within the container until the latter is fully withdrawn into the ante-chamber so that it may drop straight downward vertically and have no tendency to cant and possibly jam within the container. Therefore, I have here shown the openings 54 (see Fig. 4) as closed by doors 58, which may be of cast iron since the temperature in the ante-chamber is not as severe as within the reaction chamber, which I hinge on a longitudinally extending axis 60. The door 58 is maintained in the closed position shown at the left of Fig. 4 until the container 32 is completely retracted and positioned over it, and it may then be swung downwardly to the position shown at the left to permit the coke to drop freely downwardly. The door may then be restored to closed position, permitting the container to be lled through its open top. I have herein shown these closures as supported from underneath by a transversely reciprocating beam 62 formed with a rack with which meshes a pinion 64 selectively driven from the motor 50. The end of this beam may be beveled off as shown in Fig. 4 to cooperate with the closures, and assuming it to move to the left from the position shown, it will be seen that it will gradually close the middle door and then advancing to the left engage, lift and close the lefthand door, and when moved in the opposite direction will successively release the doors and permit them to drop to the open position, exposing the openings 54 throughout their length.

To charge the containers I may provide charge cars 66 having one or more depending spouts 68 adapted to be positioned in registry with suitable openings directly above the open tops of the containers when the latter are retracted into the ante-chambers, as illustrated at the left of Fig. 1. These openings may be normally closed by seal plates l adapted to be moved into and out of position by the spouts 68 as the car is moved. A suitable measured charge of coal may be dumped into the containers from these spouts. In view of the rapid heat transfer made possible by the apparatus here shown I have found that in some cases there is a tendency of the coke adjacent the walls of the container to develop shrinkage cracks. In cases where this is` objectionable it may be advantageous to add ground coke breeze to the charge to the extent of about by weight as this tends to prevent such cracking.

I have herein shown pusher elements 12 extending through the spouts 6B and adapted to be raised and lowered by exterior operating mechanism, here diagrammed as a pinion 14. This provides means for placing pressure on the charge of coke in the container if it should by chance become jammed in order to free it and start it on its way to the hopper it.

While the containers are in the reaction chamber in the position shown in Fig; l, suitable means may be provided for obstructing the free passage of heat between the reaction chamber and the ante-chambers tending to conne the heat more closely to the reaction chamber. Herein I have shown heat-obstructing doors 16 which are carried by the containers and adapted to be positioned thereby substantially in the door-way at the end of the reaction chambers when the coking reaction is going on.l It will be understood that since these move with the doors through the door-ways in both directions they do not t tight but they obstruct the door-way and diminish the heat transfer which would otherwise take place. Herein, as best shown in Figs. 5 and 8, the door '76 consisting essentially of a pile of heat-insulating refractory bricks is mounted on one of the clevises 58 carried by the container 32 and held in position by light straps 18 of nickel-chromiumsteel. The bottom bricks of the pile may protrude downwardly through the clevis as indicated so that almost the entire end of the container is protected by insulation. The latter, however, does not reach quite down to the bottom of the container as it is not desired to permit it to drag along the sole of the oven.

It will be noted that noY doors other than emergency doors are required in the external walls of the oven so that the losses inevitable in the ordinary by-product oven when the doors are opened, that is to say, the loss of gas, the loss of coke by burning up and the loss of heat, are avoided and the labor required for sealing these doors is dispensed with.

The construction materials herein referred to are in and of themselves expensive, but in view of the very marked increase in the coking rate made possible, the lessened weight of the heating refractories and the simplicity of the system,

the capital cost of the furnace and its equipment as` compared to its output is low.

Some of the advantages attendant on the use of the apparatus described have been referred to from time to time in the course of the description and others will be apparent to those skilled in the art. I am aware that the invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof, and I therefore desire the present embodiment to be considered in all respects as illustrative and not restrictive; reference being had to the appended claims rather than to the foregoing description to indicate the scope of the invention.

I claim:

1. Equipment for coking coal comprising tunnel-like reaction chambers having gas oitakes and dened in part by vertical walls having heating ues therein separated from the reaction chambers by thin septa of silicon carbide or its equivalent, tall, narrow containers having extended side walls and narrow end walls consisting essentially of silicon carbide or its equivalent and having open bottoms and tops, means for traversing said containers over the soles of the reaction chambers with the lower margins of the sides and ends resting thereon to be supported thereby and with Vsubstantial clearance from said septa to receive heatv therefrom by radiation, and means exterior of the chambers at the ends thereof providing for charging and discharging lthe containers.

2. Equipment for coking coal comprising tunnel-like reaction 'chambers having gas offtakes and defined in part by vertical walls having heating flues therein separated from the reaction chambers by thin septa of silicon carbide or its equivalent, tall, narrow containers having extended side walls and narrow end walls consisting essentially of silicon carbide or its equivalent and having open bottoms and tops, means for traversing said containers over the soles of the reaction chambers with the lower margins of the sides and ends resting thereon to be supported thereby and with substantial clearance from said septa to receive heat therefrom by radiation, ante-chambers having charging and discharging hoppers opening to the same, tracks for receiving the side walls of the containers in the ante-chambers to support them between the hoppers and movable plates arranged for positioning temporarily to close the bottoms of the containers in the ante-chambers.

3. Equipment for coking coal comprising long, narrow reaction chambers having gas offtakes and defined in part by side walls having flues therein, tall, narrow containers of refractory material having open bottoms and tops and adapted for movement over the soles of said chambers with the lower margins of the sides and ends resting thereon to be supported thereby and with substantial clearance from the side walls thereof, ante-chambers having discharge hoppers into which said containers may dump from their open bottoms when moved thereover and lling hoppers adapted to discharge into the open tops of the containers, means in the ante-chambers for temporarily ciosing the bottoms during lling, and means for traversing the containers.

li. Equipment for coking coal comprising long, narrow reaction chambers having gas offtakes and defined in part by side walls having flues therein, tall, narrow containers constructed from thin plates of silicon carbide refractory having open bottoms and tops and adapted for movement over the soles of said chambers with the lower margins of the sides and ends resting thereon to be supported thereby and with substantial clearance from the side Walls thereof, ante-charnbers havinggdischarge hoppers into which said containers may dump from their open bottoms when moved thereover and lling hoppers adapted to discharge into the open tops of the con-` tainers, means in the ante-chambers for temporarily closing the bottoms during filling, and means for traversing the containers.

5. Equipment for coking coal comprising an enclosure, a series of independent parallel walls extending longitudinallyY within the enclosure, each wall being self-contained and capable of expansion in itself, said walls being constructed of channeled blocks of silicon carbide refractory dening heating flues therein, and the walls Vde fning tunnel-like reaction chambers, means for supplying heating gases to the i'lues, and containers for coal traversable through said chambers in spaced relation to said walls.

6. Equipment for coking coal comprising an enclosure, a series of independent parallel walls extending longitudinally within the enclosure, each wall being self-contained and capable of expansion in itself, said walls being constructed of channeled blocks of silicon carbide refractory defining heating ilues therein, and the walls defining tunnel-like reaction chambers, means for supplying heating gases to the flues, and containers ior coal traversable through said chambers in spaced relation to said Walls, said enclosure de'iining ante-chambers at the ends of said reaction chambers, there being openings therefrom into which said containers may dump and openings thereto through which they may be lled.

7. Equipment for coking coal comprising an enclosure, a series of independent parallel walls extending longitudinally within the enclosure, each Wall being self-contained and capable of expansion in itself, said walls being constructed of channeled blocks of silicon carbide refractory defining heating nues therein, and the walls dening tunnel-like reaction chambers, means for supplying heating gases to the flues, and containers for coal having open tops and bottoms traversable along the soles of the chambers in spaced relation to said Walls, said enclosure defining ante-chambers at the ends of said reaction chambers, there being openings therefrom into which said containers may dump and openings thereto through which they may be lled, and means in the ante-chamber for closing the bottoms of the containers during illing.

3. The container for coal to be coked having open top and bottom and extended side walls and narrow end walls of thin tiles of silicon carbide refractory set in a frame of heat-resisting alloy.

9. The container for coal to be coked having open top and bottom and extended side walls and narrow end walls of thin tiles of silicon carbide refractory hooped by heat-resisting alloy.

10. Equipment for colring coal comprising tunnel-like reaction chambers having gas orftakes and defined in part by vertical walls having heating flues therein separated from the reaction chambers by thin septa of silicon carbide or its equivalent, tall, narrow containers having extended side walls and narrow end Walls consisting essentially of silicon carbide or its equivalent and having open bottoms and tops through which they may be discharged and charged respectively, said containers adapted to lie within the reaction chambers with substantial clearance from said septa to receive heat therefrom by radiation and with the lower margins of the side and end walls supported by the soles of the reac tion chambers and movable means at the end of the chambers for temporarily closing the bottom of the containers.

11. Equipment forcoking coal `comprising an enclosure, a series of independent parallel walls extending longitudinally within the enclosure, each wall being self-contained and capable of expansion in itself, said walls being constructed of channeled blocks of silicon carbide refractory defining heating flues therein, and the walls deiining tunnel-like reaction chambers, means for supplying heating gases to the flues, containers forV coal having extended side Walls and narrow end walls consisting essentially of silicon carbide or its equivalent and having open bottoms and tops through which they may be discharged and charged respectively, said containers adapted to lie within the reaction chambers with substantial clearance from said septa t receive heat therefrom by radiation and with the lower margins of the side and end walls supported by the soles of the reaction chambers and movable means at the end of the chambers for temporarily closing the bottom of the containers.

l2. Equipment for coking coal comprising a set of tunnel-like reaction chambers set side by side defined by a sole and longitudinally extending side walls having flues therein, containers of refractory material having open bottoms and tops adapted to rest on the sole between said walls with substantial clearance from the latter, the sole contacting with the lower margins of the side and end walls of the containers to close the bottoms, means for moving the containers in and out of the chambers, longitudinal supports at the ends of the chambers to receive the lower side edges of the containers and denng between them spaces through which the containers may dump, closures for said spaces hinged on longitudinal lines, and an underriding support for said closures transversely shiftable to release and reposition the same.

13. Equipment for coking coal comprising a set of tunnel-like reaction chambers set side by side defined by a sole and longitudinally extending side walls having nues therein, containers of refractory material having open bottoms and tops adapted to rest on the sole between said walls with substantial clearance from the latter, the sole contacting with the lower margins of the side and end walls of the containers to close the bottoms, means for moving the containers in and out of the chambers, longitudinal supports at the ends of the chambers to receive the lower side edges of the containers and defining between them spaces through which the containers may dump, closures for said spaces hinged on longitudinal lines, and a transversely reciprocable beam movable beneath the doors in the closed position.

14. Equipment for coking coal comprising a tunnel-like reaction chamber having a gas olitake and comprising a sole and lateral walls having heating lues, a container of refractory material having an open bottom and top adapted to rest on the sole with substantial. clearance from the side Walls, the sole contacting with the lower Vmargins of the side and end walls of the containers to close the bottoms, means for moving the container in and out of the chamber, longitudinal supports at the end of the chamber to receive the lower side edges of the container and defining between them a space through which the containers may diunp, a movable door for closing said space, and means for lling the container through its top when positioned above the door.

15. Equipment for cokihg coal comprising a tunnel-like reaction `chamber having a gas oirtake and comprising a sole and lateral walls having heating flues, a container of refractory material having an open bottom and top adapted to rest on the sole with substantial clearance from the side walls, the sole contacting with the lower margins of the side and end Walls of the containers to close the bottoms, means for moving the container in and out of the chamber, longitudinal supports at the end of the chamber to receive the lower side edges of the container and deiining between them a space through which the containers may dump, a closure for said space hinged to swing about a longitudinal axis, and means for filling the container through its top when positioned above the door.

16. Equipment for cokng coal comprising a tunnel-like reaction chamber having a gas olftake and comprising a sole and lateral Walls having heating nues, a container having an open bottom and top adapted to rest on the sole with substantial clearance from the side Walls, means for moving the container in and out of the chamber, longitudinal supports at the end of the chamber to receive the lower side edges of the container and dening between them a space through which the containers may dump, a c10- sure for said space, means providing for the opening of the same to expose said space throughout its length at the same moment, and means for filling the container through its top when positioned above the closure.

WILLIAM A. OGG.

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