US2039081A - Apparatus for the carbonization or heat treatment of solid materials - Google Patents

Description

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OFF1E APPARATUS FOR THE CARBUNIZATION 0R HEAT TREATMENT @IF SQLID MATERIALS Stewart Roy lllingworth, Fernwood, Radyr, Wales, assignor to The Illingworth Carbonization Company,

1933, Serial No. 704,011

In Great Britain November 30, 1982 4 Claims.

This invention relates to a method and apparatus for the carbonization of coal or like carbonaceous material and more particularly to an apparatus for use in the low temperature car- 'bonization of coal and coal briquettes.

At present it is the more common practice in the carbonization of coal and like material to employ retorts of the vertical type into which the material is charged and from which at predetermined intervals it is discharged.

While the vertical form of retort has proved extremely satisfactory up to the present for carbonizing coal where the size and character of the resultant product e. g. coke is not important, diiiiculties arise especially when handling ovoids or coal briquettes due chiefly to caking of the coal.

Horizontal coke ovens with a reciprocating floor are known for feeding the coke through the retort. In practice, however, attempts to employ a horizontal type of apparatus for treating shaped fuel have been confined mainly to the rotary form but while this gives a continuous oven, the results are not all that are desired, either as regards the product obtained or the operation of the retort from a mechanical point of view. Attemptsto use an endless conveyor for feeding the coal have failed owing to the special steel required to withstand the temperature of the oven and which if not employed would soon result in a mechanical break-down.

According to the present invention the retort apparatus comprises a horizontally extending heating surface, over which the material undergoing treatment is passed, means for supporting the surface so as to permit of a to and fro endwise movement thereof within the retort chamber, and actuating means for imparting movement to the surface and a flexible seal or gas tight connection device is provided between the moving surface and the stationary part of the retort with the object of sealing off the supporting and actuating means from contact with the hot gases within the heating chamber whereby these parts operate in a cold or comparatively cool atmosphere.

The heating surface may consist of a tray carried by a frame structure mounted for toand fro longitudinal movement Within the chamber of the retort, the actuating means, which engages with the structure being arranged to effect a displacement of the structure in one direction and means being provided for sharply arresting its return movement to cause the material to be fed along the tray.

By arranging the actuating means for the heating surface together with the supporting means therefor outside to the retort chamber since this enables a considerable saving in the cost of the materials used in the construction of the apparatus to be effected and only in the case of those parts working within the retort are special heat resisting steels required.

This arrangement may be achieved by providing the tray with a cover plate which constitutes the top of the heating chamber within the retort and by sealing off the moving tray from the working parts by means of a flexible seal which permits the necessary movement of the tray but confines the hot gases within the retort chamber.

A liquid seal will be found to give satisfactory results and in one embodiment of the invention there is attached to the cover plate or supporting structure a peripherally extending flange which dips into a suitable liquid.

The invention is illustrated in the accompanying drawings, in which:-

Figures 1a, 1b, 1c and 2 are respectively vertical and transverse sectional views of a retortsetting having three carbonizing retorts with their associated mechanisms, the interior of the retort chamber being shown in detail and on a larger scale in Figures 3 and 4 which are respectively a sectional elevation and transverse sectional view of a single retort chamber with its carbonizing tray and liquid seal constructed in accordance with the invention, it being understood that in Figures 1a, 1b, 1c the liquid seal is omitted.

Figures 5 and 6 are views showing respectively in section and elevation an alternative manner of supporting the carbonizing retort for to-and-fro longitudinal movement.

Figures 7 and 8 are similar views illustrating a modified form of support for the carbonizing retort.

Referring to the accompanying drawings, 1 indicates generally the retort-setting which is of brickwork or other suitable refractory material, and as shown in Figure l, the setting may be divided into three ovens or heating chambers 3, t, 5, but it will be understood that it may contain only a single oven or other convenient number.

Coal or other material to be carbonized or otherwise treated in the oven is supplied from a hopper from which it passes under gravity through feed chutes to metal (carbonizing) retort trays indicated generally at it), Ii, 12 mounted in their respective ovens.

The ovens are heated by means of heating gases in the flues l1, l5 and I6 located in the floors or walls of the retort setting. The flues in some cases may be open to the oven interiors.

The retort trays are each mounted for to and fro movement in a longitudinal direction, and each tray has movement in one direction imparted to it by means of a pusher rod 23, while movement of the tray in the reverse direction is arrested by means of a buffer or stop 24.

It will be seen therefore that on its return stroke the tray will receive a jar and the material supported thereby, owing to its momentum, will move along the surface of the tray.

The trays are built up in sections 25 which are attachably connected to a box girder frame, the frame being hung by means of links 21 pivotally connected at their ends respectively to lugs 28 on the frame and brackets 29 attached to cross beams 39 in the roofs of the oven.

The pusher rods 23 extend through the end wall I of the brickwork setting opposite the discharge ends of the trays and are slidably supported in gas tight glands 3i carried on the verticals 32 of a frame structure hereinafter described.

Fast on each rod is a collar 33 which contacts with the buffers 24.

Movement may be imparted to the push rods by means of cam mechanisms each rod engaging with quick release cams 35. As shown each cam has a curved surface 36 up which the end of the pusher rod rides and during which time the tray is caused to move towards the feed end of the retort, the surface 36 terminating abruptly in order to produce sudden release movement of the tray, the cam being cut away as indicated at 31. The pusher rod at this time is now freed from the control of the cam and under the weight of the tray will return towards its initial position until it is arrested by inter-engagement of the collar with its stop.

The sudden jar imparted to the tray caused by the arrest of the latter will produce a forward movement of the material along the surface of the tray.

The cams are mounted upon shafts 38 having pulley wheels 39 and which shafts are carried upon a framework indicated generally at 40. The verticals 32 of this framework carry the buffers.

The pulleys are driven from a suitable motor 4i and it is to be noted that they are set so as to obtain as far as possible a balanced effect of the trays.

At the feed end of the setting is a structure, indicated generally at 42, supporting a feed hopper 44, the discharge end of which communicates with a bifurcated chute 46. One limb 41 of the chute feeds the uppermost retort or tray while the other limb 48 leads to chutes 49 and 50 respectively feeding the second and third trays.

At the discharge end of the retorts are alternately inclined baiile plates 5| on to which the material carbonized is discharged from the trays, the material finally passing into a sump 52 with a water seal 53.

A spider wheel 54 is provided for discharging the material from the sump on to a conveyor indicated at 55.

The oven chambers are heated by gas burnt in the flues in the normal manner. When the apparatus is to be used for drying only, the heating gases may be drawn over the material undergoing treatment.

56 is an off-take for the products of carbonization.

Referring now more particularly to Figures 3 and 4, it will be noted that in accordance with the invention the supporting and actuating mechanisms for the trays are out of contact with the hot gases since it has been found that by shutting off the moving parts of the mechanism from contact with the gases, it appreciably adds to the life of the plant and enables the use of lighter tray parts.

In Figures 3 and 4 there is shown an oven and retort which comprises a concrete bed structure 60 wherein are housed the heating flues and from which the gases pass into a chamber 6! cut off by means of a. peripherally extending water seal 62. The water seal is formed in a channel 63 extending along the four walls of the oven the end portions being indicated at 63', which it will be appreciated is of sufiicient breadth to permit of the required longitudinal movement of the tray.

The oarbonizing tray or retort indicated generally at B4 is built up from corrugated plates 65 supported along their edges on side members 66 of L-section which themselves are carried on cross bars 61, the cross bars 6'! being secured to the lower ends of short vertical channels 68 fast at their upper ends with the side channel girders 69 braced together by cross girders "l3 and end pieces H.

The top of the tray is closed in by means of cover plates 12 attached to the cross braces and to the four outer girders are secured depending seal plates 13 and M respectively which as shown dip beneath the level of the water in the water seal 62.

It will be appreciated from the foregoing that the corrugated plates constitute the carbonizing L1 surfaces and that the oven space is bounded by the water seal and the plates l2 and that the entire oven forms a rigid girder structure. This structure is supported for swinging movement by arms 15 pivotally connected at their lower ends at 16 to the cross braces and at their upper ends at 11 to transverse girders 18 forming part of the retort setting.

The transverse girders l8 are supported by longitudinals 59 which themselves are carried on posts It will be seen that this construction, apart from the fact that the supporting arms operate in the cool and are not subjected to contact with the oven gases, reduce the amount of brickwork in the retort structure.

Water seals indicated generally at 8|, 82 are provided respectively at the feed and discharge ends.

The seal 8! at the feed end is carried upon the top of the retort structure and moves therewith. This is of rectangular shape and in the centre of the water seal is a space 83 into which opens the lower end 84 of a feed pipe 85.

In the feed pipe is a rotary feed spider 86 and a gas off-take 8?. Attached to the lower end of the feed pipe are plates 88 which dip into the water seal.

The material from the discharge end of the tray falls into the water seal 82 which is contained in a trough 89 formed in the concrete structure, the lower end 9i] of the concrete structure supporting the water seal for the oven extending below the level of the water.

Referring now to Figures 5 and 6, the cross braces Til of the carbonizing retort or tray are provided with downhanging extensions 93 which project beyond the sides of the water seal 62 and to the outer ends of which are secured flexible arms 94 whose lower ends are anchored rigidly at Qii to a beam 96 of the retort setting.

It will be understood that the tray is supported by a series of such arms 94 formed of suitable springy material and that endwise movement is imparted to the tray in the same manner as illustrated in the preceding Figures 3 to 6.

Referring now to Figures 7 and 8 the tray is supported by rollers 9i mounted in suitable bearings 98 on extensions 99 of the cross braces iii. The rollers Q?! are fianged and engage tracks iiiii along which they run.

Movement may be imparted to the tray by means of cam mechanism as previously described, and the tracks may be inclined so that the pulley pushes the tray up the incline of the tracks. A return spring (not shown) may be found necessary to secure the necessary jigging action.

Alternatively the carb-onizing retorts or trays may be actuated by an unbalanced pulley mechanism.

As described above the heating flues iii, 55, iii may be provided in the dividing walls of the retort setting, the fines being out of direct contact with the respective retort chambers which are rendered gas-tight to enable the products of carbonization to be withdrawn through a suitable oif-take in the usual manner. If desired the heating fiues may consist of metal tubes for the circulation of heating gases.

The heating system may be operated upon the principle described in my prior specification No. 350,960 wherein the gases passing through one series of fines are boosted to the temperature required for circulation in the next series of dues. It will be obvious also that if the retort is to be used only for drying purposes the gases may be circulated in direct contact with the material so that the fiues may be dispensed with.

Both the feed chutes from the hopper and the pusher rods extend into the ovens through gastight joints, the cam and driving mechanism therefor being external to the ovens. In operation it will be obvious that the movement of the pusher rods will produce an endwise displacementof the trays and the subsequent (differential) arrest of the return movement will impart a sudden jolt which will cause the material on the respective trays to slide forward and ultimately be discharged at one end.

It is visualized that a suitable length for the tray will be -30 x 6 bread and in the case of an enclosed tray 2' deep.

It will be clear that the speed of travel and hence the time of heat treatment or carbonization in the oven can be varied by firstly the number of strokes per minute secondly by the length of stroke, thirdly by the amount of the bump which is dependent on the distance through which the tray returns before arrest of its motion, or a combination of these factors. The weight of charge and tray will influence the results in conformity with the operation of the differences in inertia.

Trials with a 20' tray weighing cwt. indicate that with this weight a short stroke of some and a bump of 1 operating at 60 strokes per minute gave a travel at a rate required to carbonize in one hour. It will be obvious however that these figures will vary with the nature of the material undergoing treatment and clearly also with the arrangement illustrated in Figures 5 and 6 higher speeds in the nature of a jig may be achieved.

The retort of this invention is especially suitable for the carbonization of shapedfuel e. g. ovoids pressed from a mixture of coal, breeze and a suitable binder for which tar may be used.

In most processes wherein ovoids are carbonized it is essential to employ pitch as the binder, the amount of pitch utilized being relatively high, say 8% in order that the ovoids will withstand handling prior to carbonization. In this invention not only can the ovoids production be incorporated with the feed mechanism, but the quantity of pitch can be appreciably reduced to say 3% per gram (2 oz.) ovoid, and moreover can be replaced by crude tar or fractions thereof since the nature of the movement through the retort chamber is not such as to cause disintegration of the ovoids.

It is visualized that in actual practice that the tar coal mixture will be fed to an overhead bunker and pressed in a press immediately be neath. Between the press and the feed chutes may be provided a screen to remove debris. The ovoids or shaped fuel will fall without breakage into the chute and thence pass on to the retorts from which it issues as a hard dense smokeless fuel.

t intervals of an hour the briquette press will be set to work for half an hour, and if it is of three tons capacity it will serve the three units visualized.

In the retort setting of Figures 3 and 4 also it is contemplated that insulation can be dispensed with by mounting another carbonizing tray above making in eifect a single swinging unit with an upper and lower deck. The ovoids will be carbonized on the lower tray and coal carbonized to a sufiicient extent on the upper tray.

Without actual test it is difficult to say if there will be enough heat on to the second tray for the required degree of carbonization, but failing this there should be sufficient heat to dry coal on upper deck. In this connection however experiments with a double deck tray have been carried out and it is mechanically sound from the standpoint of coal on the top tray and ovoids on the bottom tray carrying forward in a regular manner.

In the event of drying or pre-carbonizing in the same oven as the carbonization of the ovoids, the water seal at the discharge end would be dispensed with and a discharge feed on the lines of that described in my prior specification No. 276,70i would be substituted.

It will be appreciated that the extraordinarily small capital cost, low power of operation and labour costs, ease of renewals, would render this tray retort of this invention of importance in the carbonization of lignites, shales and the like, which it is to be understood are included in the term like carbonaceous material. Moreover the fact that the vapours pass from the hot coal into a cool zone makes for maximum oil production and an absence of cracking.

Another important feature is that it is thought that with this sliding action what are known as the bituminous coals which become very plastic and adhere under heat can be carbonized without sticking, in which case the retort has a further advantage in the production of breeze for mixing with coals.

The retort of this invention may be employed in conjunction with a retort operating at higher temperature, the products for the first retort being discharged without cooling into the second and submitted to a further period of carbonization at higher temperatures. By this means the total gas production can be increased and the resulting fuel although of low volatile content is still highly reactive.

The apparatus has the merits of simplicity of construction, cheapness in erection, and low renewal costs; the brickwork is robust construction or ordinary shapes. The only parts requiring renewal are the trays. All delicate parts demanding attention, e. g. oil are in the cold.

The ovens can be built in batteries not only as to height, but built adjacent to one another.

The manufacture of the shaped fuel in situ obviates the usual procedure of an independent plant for its production, and enables an oil or tar ovoid or briquette to be handled. Such briquette without carbonization would be worthless.

The apparatus can be utilized to precarbonize a portion of the coal, to be mixed with fresh coal, so as to produce the requisite blend for a satisfactory product and in this case the precarbonized product may be cooled by mixing with wet coal, both as set out in my previous patents.

The apparatus of this invention is suitable for the carbonization of briquettes of a mixture set out in the British specification No. 212,663 the agglomeration being effected either with pitch, heavy tar oil or mineral oil; in certain cases moist coal can be used alone.

What I claim is:-

1. In apparatus for the continuous carbonization of coal and like carbonaceous material and briquettes prepared therefrom, the combination of a retort setting of refractory material having a carbonizing chamber, a frame structure having a cover plate which constitutes the top of the retort chamber and mounted for limited to and fro lengthwise movement within the carbonizing chamber, a tray for the material undergoing treatment depending from the frame structure, means forming a flexible seal all around between the cover plate and the lower portion of the retort chamber, supporting members for the frame structure and its attached tray located exterior to the carbonizing chamber and actuating means co-acting with the frame structure for effecting displacement thereof and its tray and for sharply arresting its return movement to cause the material to be fed along the tray, said flexible seal being sufficiently flexible to permit the aforesaid displacement of the frame structure without breaking the seal at any point around the frame structure.

2. In apparatus for the continuous carbonization of coal and like carbonaceous material and briquettes prepared therefrom, the combination of a retort setting of refractory material having a carbonizing chamber, a frame structure having a cover plate which constitutes the top of the carbonizing chamber mounted for limited to and fro movement within the retort, a tray for the material undergoing treatment carried by and underneath the frame structure, a channel extending all around the lower portion of the carbonizing chamber for containing a sealing material, a depending peripheral flange extending all around the frame structure for co-operation with the sealing material in the channel, supporting members for the frame structure and its tray located on the outside of the cover plate and actuating means co-acting with the structure for effecting displacement thereof and for sharply arresting its return movement to cause the material to be fed along the tray, said channel being sufficiently wide to permit the flange to have necessary movement without breaking the seal.

3. Apparatus as claimed in claim 2 in which the actuating means comprises a freely slidable push rod provided with a collar and adapted at one end to engage with the tray-carrying structure, a fixed stop carried by an outside rigid structure for co-operation with the collar on the rod in order to arrest the frame structure in its return movement, quick-release cam means contacting with the other end of the rod and means for actuating the cam.

4. Retort apparatus suitable for the continuous carbonization and heat treatment of coal and shaped fuels prepared therefrom comprising a retort-setting, a horizontally extending heatingsurface, over which the material to be treated passes, means for supporting the surface so as to permit to-andfro endwise movement within the retort-setting embodying relatively movable elements, a sealing structure enclosing the upper side of the surface to form a closed heating chamber above the heating-surface, and actuating means for imparting to-and-fro movement to the heating-surface, both the movable elements of the supporting means and the actuating means being arranged externally to the sealing means for the purpose specified, said sealing structure embodying means attached to the heating-surface and cooperating means on the retort-setting constituting a seal sufficiently flexible to permit a the to-and-fro movements of the heating-surface without breaking the seal.

STEWART ROY ILLINGWORTH.

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