US2026439A - Apparatus for molding fuel briquettes - Google Patents

Description

Dec. 31, 1935. E SAMAL 2,026,439

APPARATUS FOR MOLDING FUEL BRIQUETTES Filed Sept. 19, 1933 2 Sheets-Sheet 2 Patented Dec. 31, 1935 UNITED STATES PATENT OFFICE APPARATUS FOR MOLDING FUEL BRIQUETTES Application September 19, 1933, Serial No. 690,154 In France September 20, 1932 Claims.

The present invention relates to a process for the agglomeration of dust or ne particles of solid fuels, and to means for the application of this process.

5 The processes heretofore known for the manufacture of agglomerate blocks of fuel consist:

(a) in adding a body, improperly called abinder (consisting generally of pitch) in determined proportions to the fuel to be agglomerated;

(b) in compressing the mixture of molds (briquette presses or bu'llet presses), and

(c) in heating these compressed bodies in furnaces of dierent kind, the purpose being to harden the agglomerates and to withdraw a part of the added binding agent and to recuperate the same if possible.

The main drawbacks of these known processes f are:

1. A slow and incomplete carbonization owing to the volume and to the density of the moulded products, and to their bad conductivity, so that furnaces of great dimensions are needed for a sufficient production;

2. There is a great proportion of waste at the loading of the furnaces, and in the furnaces themselves owing to a disaggregation or crushing of the agglomerates.

The hardening by heat, of products previously agglomerated by molding is, to a great part, due to the formation, by cracking or by distillation of the tar or pitch, of molecular active surfaces (active coal included) which are the main cohesion agents. It is obvious that in order to obtain the mutual attachment of the molecules by the most of their active surfaces, it is essential yto permit the free movements of the molecules, which is not the case if the substance has been previously compressed. The present invention is derived from this deduction and will be better understood by reference to the accompanying drawings wherein Fig. 1 is a diagrammatic illustration of a cracking curve,

Fig. 2 is a cross-section through a distillation furnace working at low temperature,

Fig. 3 is an enlarged cross-sectional detail View of the compression and cracking arrangement, and

Fig. 4 is a similar view of another embodiment of this apparatus.

The main directing idea of the invention is, as

follows:

When a solid fuel in state of fine sub-division or of dust, contains, either naturally or by addition, hydrocarbons apt to produce, by cracking, a sufficient proportion of condensed molecules (active molecules), a cohesion of molecules is obtained which is much superior to that obtainable by the processes hitherto known, this vhigher cohesion being had by the action of pressure, combined with appropriate mixing permitting the heavier molecules to occupy the most favorable position.

Consequently the process according to the invention consists:

1. In conducting the distillation at low temperature or operating at the stage of 'semi-distillation, in thin layers, the raw material consisting of sub-divided fat coal or of its dust or of close-burning coal, to which are added, if necessary and in appropriate proportions, hydrocarbons of the nature above specified, the heating speed and the temperature (about 500 0.), at which this distillation is carred out, varying in accordance with the nature of the fuel.

The distillation is carried out in such a manner that hydrocarbons are liberated and brought intobound molecular instability, these hydrocarbons being such that they are apt to give, in the succeeding phase (cracking and molecular condensation) more condensed hydrocarbons (heavy hydrocarbons), the active molecular surfaces of which will constitute, under4 the conditions of treatment, the cohesion agents of the whole mass.

At this moment a certain proportion of the mass has been brought into a state of molecular bound instability, which state is comparable, in the resistance of materials, to that of a beam having undergone a permanent deformation; it is known thatsuch a beam breaks easier under the action of overload than if it has not undergone a y preliminary permanent deformation.

In a similar manner, in the state of molecular bound instability, the hydrocarbon molecules are in conditions very close to cracking and are apt to, and the experience has proved that these molecules will crack with a great facility under the action, for example of an even moderate pressure. From the illustration of Fig. 1 it will appear that while a pressure of 2000 kg. is necessary for obtaining cracking at a temperature of 100 C., a pressure of 15 kg.will be suicient for the cracking at a temperature 450 C.

Y 2. The substance brought in this way into a state of molecular bound instability in a furnace working at low temperature is treated in a special mixing and compressing apparatus to permit:

(a) the escapement of gases included in the distilled mass;

(b) the progressive compression and the nal cracking, and

(c) the greatest liberty of orientation of the molecules with active surfaces obtained by cracking.

3. If the combustible to be agglomerated is deprived, totally or partly, of constituents giving, after the distlation specified under 1, hydrocarbons having a sufficient bound molecular instability for cracking under the conditions of treatment, appropriate additions are eifected, previous to distillation, imparting to the mass the necessary proportion of the hydrocarbons specifled above.

The advantages of the specified process are as follows:

(a) the heating of the agglomerates and all drawbacks derived therefrom are suppressed;

(b) owing to the distillation `being effected in thin layers and at high heating-speeds, the dimensions of the distillation furnaces can be considerably reduced with regard to the Ausual dimensions of the usually known furnaces;

(c) the proportion of waste is reduced to a minimum owing to the fact that theagglomeration is effected as last operation;

(d) the cohesion of the agglomerates can be regulated in a certain measure by eiecting a more -or less complete cracking;

(e) the treatment based'on distillation at low temperature and in thin layers has 'the following advantages:

1. It provides for the formation and the -best possible homogeneous repartition of molecules in state of bound instability, in the shortest time;

2. It permits to recover of distillates -of -high commercial value which can be used anew for another cycle.

The rst phase of the process can be effected in continuous distillation furnaces working at low temperature and with rapid heating, the nely sub-divided mass or dust to be treated (to which, if necessary, hydrocarbons have been added) being distributed and distilled in thin layers.

A suitable furnace of this kind is shown, merely in the way of an example, in Fig. 2. The'coal dust is introduced at g, after a preliminary ldrying, and distributed with aid of a regulating funnel h on a conveyer i consisting of a metal sheet and provided with Scrapers for advancing the coal, agitating the same and distributing it in thin layer upon the metallic table surface :i heated, for example by a gas burner 7c. The formed semi-coke leaves the furnace through a discharge funnel l. At this moment the hydrocarbon molecules are brought into the state of vmolecular bound instability.

The second phase of the process is eiected in a special apparatus, for example such as representedfin Fig. 3 and provided with a conical screw b revolving in a truncated body a and mixing the material, whereby the gases included in the mass are permitted to escape and a perfect molecular contact is secured permitting the molecules to adjust themselves in the best suitable direction.

The screw b is rigid with a shaft c supported by bearings d1, Vd2 and drivenV by a speed reducing gear. The truncated shell or body a is provided near its larger portion with a Yfeeding mouth-piece e connected directly and tightly to the discharge funnel l of the distillation furnace.

The endless screw p mixes the material and vties Aof 'the mass. exchangeable, preferably in such lmanner that distributes in the same, the liberated hydrocarbon molecules being brought into state of bound instability by the distillation. Furthermore, the screw advances the material in the body a and leads it into a` chamber of greater conicity forming a cracking cell or open cracking mold. The cracking is produced in this cell owing to the sudden increase of pressure in the same, due to the greater conicity, the gases escaping freely through the open section f1 of the cell f. 10

Since the temperature, at which the material leaves the furnace, is relatively high, a slight pressure (the one furnished by the conicity of the cell f) applied during a relatively short time (the one determined by the length of the cell f 15 and by the speed of the screw b) suffices to effect the cracking of moleculescompare the cracking curve, Fig. 1 under the condition that these molecules have been brought into the state of Cil Ybound instability. The cracking curve is in its 20 final position nearly hat; hence for a great difference -o'f temperature the difference of pressure for obtaining cracking is very small. Consequently, even if the material has not been interial into the'cell f; in this manner a restoration of pressure is obtained by the regulating a'c- 30 tion of the screw -b thus supplyingthe additional pressure required by the diiferences of tempera- 4ture of the coal in the cell.

The'speed 'of the screw, its dimensions and the conicity of the cell ,f vary with the nature of ithe'B coal to be-treated.

The cracking is hence eifected by small quanti- The body m of the cell j is stopping of the apparatus during a time sufficient 40 for-cooling of the material and of the gases contained in the cell is not necessary.

'For this purpose a whole series of cells m1, mz, ma (Fig. 4) may be provided, these cells being mounted peripherally on a revolving disc io '45,

advancing intermittently after each filling -of the lower cell by the screw f, this advance being eifected by a driving screw 't. The said disc o revolving upon its shaft'v which is supported by the bearing u of the support p. During the in- '50 termittent rotation the conical cells f are closed at their greater portion by a fixed plain disc p situated at a slight distance from the great-er portion of the cells so as to avoid the expansion `and deformation of the agglomerated masses. 55

This expansion and deformation may occur under the action of gases impregnating the mass and of those due to cracking, the tension of these gases, due to the high temperature of the mass, risking to destruct the cohesion of the product. 60

The 'cooling of the mass and of the gases ineluded therein ought to be suiicient before removal of the mass, this condition determining the ing nozzle and s a conveyer for taking away the discharged masses.

The displacement of a charged cell and the positioning of the next one (viz. the change of the mold) is automatically effected as soon as the desired pressure is obtained in the charged cell, preferably by means of a device regulating the run of the electric motor driving the disc o, this device being installed in the circuit of the motor driving the shaft c of the screw b.

The result of this process is such an agglomeration of the sub-divided coal that whilst the tenor of volatile substances is reduced, the mass is homogeneous and its texture and quality are entirely similar to those of natural coal.

It is, of course obvious that the apparatus utilized for the operations of driving out the gases, for the molecular liberation and for the compression can be devised in another, different, convenient manner Within the scope of the present invention.

What I claim is:

1. An apparatus 4for the agglomeration of dust and ne particles of solid fuels comprising a casing having an outlet opening, means for feeding under pressure the fuels when in a plastic state through the outlet opening of said casing, a conveyor, a plurality of molds carried by said conveyer, each of said molds comprising a conical shaped cell having their opposite ends opened, said conveyor being adapted to cause the larger opened ends of the cells of said molds to register in succession with the outlet opening of said casing whereby the plastic fuel may enter and completely ll each cell, means for closing the larger opened ends of each cell of said molds after they have been filled with the plastic fuel and means for subsequently ejecting the fuel so formed within each mold.

2. An apparatus for the molding of coal briquettes comprising a support, a casing mounted upon said support having a conical shaped compartment therein, said casing having a material receiving opening within one end thereof and a discharge opening in the opposite end thereof, a conveyor mounted upon said support, a plurality of molds carried by said conveyor and each mold having a conical shaped cell formed therein of less area than the conical shaped chamber formed within said casing, means for intermittently driving said conveyor, whereby the molds may pass in succession by the discharge opening of said casing and means arranged within said casing for forcing und-er pressure the material contained therein through the discharge opening of the casing into the cells of said molds.

3. In a device of the character described comprising in combination a support, a casing mounted upon said support and having a conical shaped chamber therein, a feeding hopper communicating with one end of said chamber and a discharge opening communicating with the opposite end of said chamber, a conveyor, a plurality of molds carried by said conveyor, each mold having a conical lshaped cell formed therein and the opposite ends of each cell being opened, means for transmitting an intermittent motion to said conveyor whereby one of the opened ends of each cell of said molds will at times be Ycaused to register with the discharge opening formed within said casing and a plate permanently' mounted upon said base for closing 10 at times one of the opened ends of each cell of said mold.

4. In a device of the character described comprising in combination a support, a casing mounted upon said support having a conical 15 shaped chamber therein, a feeding hopper communicating with one end of said chamber and Y a discharge opening leading from the opposite end of said chamber, a stationary disc mounted upon said support, a bearing formed with said 2O disc, a shaft journalled Within said bearing, a rotatable disc fixedly connected to one end of said shaft, a plurality of molds mounted within and arranged adjacent to the periphery of said rotatable disc, each mold having a conical shaped 25 cell formed therein and the opposite ends of each cell being opened, said stationary disc having a discharge opening formed therein communicating with the discharge opening of said chamber of the feeding hopper, means for transmitting 30 an intermittent motion to said rotatable disc whereby one of the opened ends of each cell of said molds will be caused to register with the discharge opening formed within said stationary disc, a discharge nozzle arranged Within said 35 stationary disc at a point remote from the discharge opening formed therein, and an ejecting device adapted to enter each mold when the latter registers with said discharge nozzle whereby the contents of each mold may be ejected 40 therefrom.

5. In a device of the character described comprising a base, a vertically positioned disc formed with said base, a bearing formed with said disc,

a shaft journalled within said bearing, a wheel 45 keyed to said shaft, means for transmitting an intermittent movement to said Wheel, a plurality of molds mounted within and arranged adjacent the periphery of said Wheel, said vertically positioned disc having a pair of oppositely disposed .50 openings formed therein, means communicating with one of the openings of said disc for feeding a charge to each mold as it registers therewith, an ejecting device for ejecting the charge from each mold and causing the same to pass through 55 the other of said openings formed Within said disc, each mold having a conical shaped cell formed therein and the opposite ends of each cell being opened and said disc extending over and closing one of each of the opened ends of the 60 cells of said molds.

EUGNE SANIAL.

Images