US1829268A - Shaft furnace for treating solid materials with gases - Google Patents

Description

E. EDWEN Get 2?, E1931.

SHAFT FURNACE FOR TREATING SOLID MATERIALS WITH GASES Filed Aug. 17, 1928 3 Sheets-Sheet 1 E. EDWIN 1,829,268

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Oct. 27, 1931.

SHAFT FURNACE FOR TREATING SOLID MATERIALS WITH GASES Filed Aug. 17, 1928 Fig-2 E. EDWIN 1,829,268

SHAFT FURNACE FOR TREATING SOLID MATERIALS WITH GASES Oct. 27, 1931.

Filed Aug. 17, 1928 3 Sheets-Sheet 3 gm uzntoz shaft furnaces a Patented ct. 27, 1931 UNITED STATES PATENT OFFICE 'EMIL EDWIN, 0F TRONDHJEH, NORWAY, ASSIGNOR TO NORSK STAAL ELEKTBISK-GAS-' REDUKTION, OF OSLO, NORWAY SHAFT FURNACE FOR TREATING SOLID MATERIALS WITH GASES Application filed August 17, 1928, Serial No. 300,293, and in Norway August 22, 1927.

a thorough contact of the gases with the en- .tire surface of the solid material. In the best way this has been realized by causing the gases to pass through layers of the solid material. As the solid material however in most cases requires considerable time for complete reaction with the gases the ordinary shaft furnace with a shaft of considerable height has been devised as the simplest and in many gases the most effective apparatus for'the said purpose. Although the principle of the shaft furnace from a theoretical point of view is an ideal one for carrying out reactions between solid materials and gases nevertheless the field of utilization of this type of furnace in practical work has been rather limited. This depends upon various properties in solid materials, properties which particularly appear at higher temperatures. So for instance a great number of solid materials at hi her temperature tends to sinter and bake, W ich causes a hanging of the charge in the shaft so that a regular work is rendered difiicult or even impossible. Other solid substances have the character that, when treated with gases, they lose their mechanical strength and under the high pressure prevailing in the lower part of the shaft fall to powder, which chokes the furnace and thus often renders the use of a shaft furnace impossible. Pulverulent substances can of course not be treated directly in a shaft. If'such substances are to be treated, they must necessarily first be converted into lumps of such mechanical-strength that the said inconvenience does not 'occur. As now such agglomerating or briquetting to high resistivity generally is a rather difiicult and always a-relatively costly operation, the use of shaft furnaces is out of question fora large number of pulverulent materials.

For materials which cannot be treated in great variety of furnace types has been devised which generally may be termed mechanical furnaces, such as for instance revolving furnaces, furnaces with superimposed hearths and stirring devices and many other types. All these furnaces have the common feature, that the treated material is kept in motion in order w avoid in motion continuously or in short intervals.

From their very nature these furnaces are less adapted for facilitating a reaction between the gas and the solid material. Before all the contact surface between the gas and the solid is always very small relative to the great volume of such furnaces, and in most cases the furnaces only give a very low thermal efficiency and poor utilization of the gases.

My invention relates to a shaft furnace, which under retention of the most essential merits of ordinary shaft furnaces allows the treatment of material for which these are not adapted.

According to my invention the shaft is composed of a number of separate superimposed containers with perforate bottoms in which containers the solid materials to be treated are placed.

The invention is illustrated in the accompanying drawings, in which Fig. 1 represents diagrammaticaly a vertical section of my shaft furnace, and

Fig. 2 a similar section through an aggregate for continuous work consisting of three cooperating shaft furnaces.

Fig. 3 is a detail of Fig. 2 showing an operating mechanism.

Fig. 4 is a vertical section of one of the containers.

According to Fig. 1 the shaft furnace A is composed of a bottom piece -B,

a top piece C and a number of intermeon the bottom piece B- whereupon the top --G is put in place.

I The gas fortreating the material is intro- 'duced at the top throu h the supply pipe --D and is drawn 0 through the pipe E in the bottom B. r

The containers VI-XIII are char ed with a suitable quantity of material. material is in the form of. ains or small lumps it ma 7 containers. Tulverulent material is first agglomerated or briquetted. The agglomerate or the briquettes need not however have any great mechanical strength. The packing between the individual containers may be effected in various ways. S0 for instance a sand seal between the containers may be established, in that a groove is provided along the upper edge of containers and a projecting flange along the lower edge. Or other sorts of packings ma be used. Experience has shown however t at sufiicient obturation may be attained by roperly working the adjacent surfa'ceso the containers without use of any particular packing material.

In order to allow an exchange of the containers in regular sequence, as will be more amply explained below, the furnace is so disposed that it may be raised and lowered. To this purpose the furnace shown in Fig. 1 rests on a hydraulic piston F.

'As will be more fully explained below, the exchange of the containers is effected by horizontal displacement of the latter. To this end the containers may be provided with wheels or rollers 3 which by a lowering of the furnace are placed upon rails is and '0, Fig. 3, running horizontally along two opposite sides of the furnace on the different floors of the latter. The container, sa XIII, is then pushed out horizontally, for instance by the motion of the hydraulic piston -G. The insertion of freshly charged containers proceeds in a similar manner. By a slight lowering of the furnace the container VI- and all the parts of the furnace above it will come to rest on the rails as 0, Fig. 3 provided slightly below the lower edge of said container. A further lowering of the piston F will take the bottom piece B down, so that af-suitable free space will result between the bottom B- and the container VI, into which a freshly charged container V may be inserted. After this the whole system is raised just by the height of one container, and the furnace is again at normal work.

On account of the described mechanical arrangements the exchange of the containers may be efiected in a very short time so that the furnace works continuously; Fig. 2 shows a furnace system, which besides the furnace proper A- for gas treatment possesses a shaft A for preheating the solid material and another shaft A for cooling the en the be charged directly into the C and bottom pieces B and B'*.

Accordingtothe drawingsthe preheating gas is supposed to pass the shaft A from bottom to top and the same does the cooling gas in the shaft -.A When the gases are conveyed as mentioned above, namely from top to bottom in the gas treatment furnace -A and from bottom to top in the preheating and cooling shafts it is understood that in the gas treatment furnace A- it will be the uppermost container that carries the finished material and is removed while a container with preheated fresh charge is inserted' as the lowest one. In the preheating shaft A the case is the reverse, it is the lowermost'container that is completely preheated and is conveyed to the gas treatment furnace, while a container withfresh material is inserted at the top. In the cooling shaft things are analogous. The lowermost container carries the material, that is completelycooled, while the container with finished hot material from the gas treatment furnace is inserted at the top.

Fig. 2 shows diagramatically the various operations of displacing containers in the system. After the gas supply to the various shafts has been turned off, respectively has been connected with a by-pass, the top pieces -C*- and C are raised by the height of one container and are suspended at this height, for instance upon rails as mentioned above. Simultaneously the bottom of the gas treatment furnace is lowered by a containers height. By these operations is on the one hand the container XIII set free and on the other hand a free space is obtained below the container VI into which a container may be inserted. In this position of the shafts the displacement of the containers is carried out, in that the container XIII is transferred to the cooling shaft as the top container here, the completely cooled container XVII-- at the bottom of the cooling shaft is removed from the system, the completely preheated container V at the bottom of the preheating shaft is transferred to the gas treatment furnace as the lowermost container here, and the container -I which is charged with fresh cold material is introduced at the top of the preheating shaft. After these displacements have been carried out, the bottom pieces B and B of the preheating and cooling shafts are raised under the respective lowermost containers in these shafts. A slight further raising of these shafts unlocks the arresting devices as explained later of the top pieces and of the lowermost containers. The preheating and cooling shafts are now lowered by one containers height, simultaneously as the gas iii.

treatment furnace is raised by just the same amount unto the top piece -C. By these operations the Whole system is again in work and all the shafts are in proper position for the next series of displacements.

Fig. 3 gives, by way of example, a mechanism for operating the movable parts of the furnace. The mechanism is shown in relation to one shaft only, the cooling shaft A but the mechanisms for the pre-heating shaft A and the furnace A are similar.

The two-armed lever 0 at the bottom of a furnace is pivoted at d. The lever 0 is pivotally connected to a rod 6, which at its upper end 7 is pivoted to a two-armed lever g, w lch is pivoted at bnear the top of the furnace. The right hand arm of the lever g is a'rail is while the left hand arm of the lever carries a counterweight Z.

An elbow lever m is provided, which is pivoted at 'n. The right hand armof the elbow lever is a rail-like pawl 0, while the left hand arm carries a counterweight p, and is connected by links 1' and 1* with a two-armed lever s, which is pivoted at t. The right hand arm of the lever 8 slides along a cam or operating surface won the side of the furnace bottom B Finally, there is provided at, the side of the lowermost container (XVII) a rail 0, pivoted at w. All of the containers are provided on opposite sides near their upper edges with rollers y, and the upper as well as the lower edges of the containers project.

The movements of the various parts of the l furnace shaft A are effected in the following manner, when, as shown in Fig. 2, a container XIII is to be inserted as uppermost container while the lowermost container XVII is to be removed:

First, the top C is hoisted up the height of one container, in order to produce a free space for the container XIII (Fig. 2) that is to be inserted. Then the bottom B is slightly lowered by means of the hydraulic piston supporting it, so that the container XVII comes to rest with its rollers y upon the rails 'v, and the container XVI and those above are received and supportedby the pawl-like rail 0. The bottom B goes further down and its lower edge pushes lever 0, rod 6, lever g and rail is into the position shown in dotted lines. This is the position for change of containers. The container XIII is inserted horizontally on the rails is. The container XVII is pushed out of the furnace shaft rolling up on the rails o and the vertical length of the shaft is re-established. Now the bottom B is raised up to the container XVI (the container XVII being now removed). As the bottom B rises, lever 0 is released from the lower edges of bottom B and rod 6, lever g with rail is return again into the position shown in full lines under influence of the counter-weight Z which causes the left end of lever c to remain in touch with the bottom B rising with this bottom under the top G raili is now releases, and top C is lowered onto the column, whereupon the cooling shaft is again ready for work.

As mentioned above and as is easily understood the several movements of the preheating shaft A is quite similar to those of the cooling shaft A as described above. In both these shafts a container has to be inserted at the top of the shaft and another container is in the same series of operations removed at the lower end of the shaft. As to the operation of the gas treatment shaft A, this is effected in analogous manner, and by similar devices, onl 'with slight modifications in so far that in this shaft the uppermost container (XIII) has to be removed while a lowermost container V has tobe inserted. The operating devices for shaft A are shownin Fig. 1, corresponding parts are marked with corresponding letters in Fig. 3, but in this case provided with ex onents. When the top container (XIII) is to be displaced into the cooling shaft and a container (V) is to be inserted at the lower end of the shaft A (see Fig. 2) the operations are as follows:

The bottom piece B is lowered; whilethe top piece C remains in place the container XIII is lowered by a very short distance and comes to rest with its rollers upon the rails V on which it may be conveyed into the cooling shaft (see Fig. 2). The bottom piece B travels a little further downwards. By the play of the levers s, m, the pawls 0 are brought into position to support the rollers of the container VI (the position of the pawl is indicated in dotted lines). When the bottom piece now travels further downwards the container VI and all containers above it are retained as carried by the pawls 0. The bottom piece B travels still further downwards by a distance of a little more than one containers height, thus leaving a free space be low container VI. By this last named movement of the bottom piece the rails is by the action of levers c, g are brought into position (shown in dotted lines) to receive the fresh container V (Fig. 2) which is now inserted from the preheating shaft A into the free space below the container VI see Fig. 2.

Now the bottom piece B is raised, the rails is are released from the rollers of the container V and are swung aside, the pawls 0' are likewise released from the rollers of container VI and are swung out, the uppermost container XII is raised upon the top piece C thereby swinging aside rails o and the whole shaft A is again ready for work.

As will be seen from the receding description the movementstakep ace in such mannor, that a raising of the gas treatment furnace is simultaneous with a lowering of the preheating and cooling shafts. By this arrangement the moved masses are balanced so that onlylittle total energy is required for efi'ectin the movements.

It wi 1 be understood that the furnace described above may be modified in detail in various respects, so for instance particularly with regard to the devices for holding the ofroastingoperations, for reduction by means of gases, for treatment of qgas mixtures by solid catalysts and so on. he furnace may be used for material of any size, for pulverulent material after -a-gglomerating or briquetting. The distribution of the charge on a plurality of containers involves the advantage that the material is only exposed to low pressure. A comminution, which easily ocours in the usual shaft furnaces, is complete ly avoided. In-agglomeratin or briquetting the material even a weak bin ing is sufficient to prevent breaking and crumbling. Even a briquetting by pressing alone without subsequent burning is amply sufficient. Furthermore the material remains perfectly at rest in the containers. The gas passage is therefore not altered during the treatment as is the case in the usual shaft furnaces where the materialis dropping in quite irregular and uncontrollable manner. All the various irregularities of working arising from these conditions are avoided accordin to the invention. Thegas treatment of t e material is quite uniform through the whole of the charge. Repairs to the furnace may beaccomplished without putting it out of operation, because containers which become deficient may easily be replaced by new spare ones.

It will be understood that the described furnace under retention of the merits of the usual shaft furnace makes it possible to treat also such substances with gases which cannot be dealt with in shaft furnaces of the ordinary type.

I claim:

1. In a metallurgical shaft furnace for treatment of ores with reaction gases, a reaction chamber built up of a plurality of superimposed ore containers having perforated bottoms, means to supply a reducinggas to one end of the shaft and discharge gaseous products of reaction at the other end.

2. In a metallurgical shaft furnace for the treatment of ores 'with reaction ses, a vertical. reaction chamber built up of: plurality of superimposed-ore containers having perforated bottoms, 'means to supply a. re-

ducing gas to one end of the shaft, means to discharge gaseous productsof reaction at the other end,- means to vertically move the shaft and means tosupport it for the reqnoval of an ore container at one end of the shaft and the insertion of an ore container at the opposite end thereof.

3. In a shaft furnace, a main, a pre-heating and a cooling shaft side by side each composed of a plurality of superimposed ore containers having perforated bottoms, means to supply pre-heating gas to the pre-heating shaft, means to supply reacting gas to one treatment of ores, a reaction chamber built up of a plurality of superimposed ore containers having perforated bottoms,means to supply hot reacting gases at the top of the shaft and chamber and to discharge gaseous products of reaction at the bottom thereof, and means to serially remove the containers from the top of the shaft and to supply containers containing untreated ore at the bottom thereof.

5. A metallurgical shaft furnace composed of superimposed, separately removable ore containers having perforate bottoms, a top piece for covering the uppermost container vertically movable to permit removal of the upper container and a bottom piece for supporting the superimposed containers, and means to supply reacting gases in one piece and discharge gaseous products of reaction from the other piece.

,6. A metallurgical shaft furnace composed of superimposed, separately removable ore containers having perforate bottoms, a removable top piece to permitremoval of the upper container, a vertically movable bottom piece for supporting'the containers and for permitting the insertion of .a new container, and means to supply treating gases through one piece and means to discharge gaseous products of reaction from the other piece.

7. A metallurgical shaft furnace composed of superimposed, separately and successively removable containers having perforate bottoms, a vertically removable top piece having a gas inlet and to permit removal sh aft.

of the upper container, and a vertically movable bottom piece having a gas discharge for supporting the superimposed containers and permitting the insertion of a new container to form the lowermost portion of the shaft.

8. Ametallurgicalshaft furnace, com rising a main shaft, and an adjacent preeating shaft, each shaft composed of superimposed containers having perforated bottoms, a vertically movable to piece for each shaft and a vertically mova le bottom piece for each shaft and means to supply gases to one piece and discharge gases from the other piece, means to serially supply the containers from one end of the preheating shaft to the similar end ofthe main shaft, means to supply a fresh container to the opposite end of the pre-heating shaft, and means to discharge a container containing treated material from the opposite end of the main shaft.

9. A metallurgical shaft furnace, comprising a furnace shaft and a cooling shaft adjacent thereto, each shaft composed of superimposed containers having perforate bottoms, a vertically movable top piece for each shaft, a vertically movable bottom piece for each shaft, means to supply gases to one piece of each shaft and means to discharge gases from the other piece of each shaft, means to serially discharge the containers from one end of the main shaft and insert them in the cooling shaft at its similar end, means to supply containers at the opposite end of the main shaft and means to remove containers at the opposite end of the cooling 10. A metallurgical shaft furnace comprising a main shaft, a pro-heating shaft and a cooling shaft, a top piece for each shaft and a bottom piece for each shaft, means to supply gases to one piece of each shaft and means to discharge gases from the opposite piece of each shaft, superimposed containers having perforated bottoms composing each shaft, means to serially supply containers from one end of the pro-heating shaft to the similar end of the main shaft, means to supply freshly filled containers to the opposite end of the pre-heating shaft, means to discharge containers from the opposite end of the main shaft to the similar end of the cooling shaft and means to remove cooled containers from the opposite endof the cooling shaft.

11. A metallurgical shaft furnace comprising a hydraulic piston, a bottom piece thereon, a shaft resting on said piston composed of superimposed containers having perforate bottoms, a vertically movable top piece for the shaft, means to supply hot gases to one piece and discharge gases from the other piece, means to remove'the upper container, means to support the penultimate container with those superimposed thereon,

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