US2038623A - Apparatus for the carbonizing of fuel briquettes - Google Patents

Description

April 28, 1936. E. B. A. zwoYER E1'. Al. 2,038,623

APPARATUS FOR THE CARBONIZING OF FUEL BRIQUETTES Original Filed Aug. ll, 1931 2 Sheets-Sheet 1 W'TNESS y yg-WC/,WWSZ

r 28, 'i936 E B, A ZWOYER ET AL 2,938,323

lAPPARATUS FOR THECARBONIZING 0F FUEL BRIQUETTES Original Filed Aug. ll, 1931 2 Sheets-Sheet 2 ROTARY CARBONIZER wer com. Peep F/ ODR LINE SEI-'IERy on oF com. Fines AW mqunrrzs AT L 1?' Rl QuarTlNG PRESS 4 e* v l ATTORNEYS Patented Apr. 28, 1936 UNITED STATES PATENT OFFICE APPARATUS FOR THE CARBONIZING 0F FUEL BRIQUETTES @riginal application August 11, 1931, Serial No. 556,378. Divided and this application October 11, 1933, Serial No. 693,054. 1n Canada October 6 Claims.

This invention relates to apparatus for the carbonizing of fuel briquettes and more particularly to apparatus adapted to carry out the prooess of carbonizing fuel briquettes disclosed in our copending patent application, Ser. No. 556,378, filed August 11, 1931, which matured into Patent No. 1,950,017, dated March 6, 1934 and of which this application is a division.

The principal objects of the invention are to provide an apparatus by which the raw briquettes fed thereto are rst distributed as a single layer within a heating chamber in such manner as to be out of heat obstructing contact with each other and where they are subjected to a sudden comparatively high temperature, and then passed through such chamber as a quiescent single layer at a predetermined rate of speed such that the raw briquettes are maintained in such high heat region for a sufficient time to surface-harden them but not long enough to result in combustion or to carbonize them throughout, and finally passed through a carbonizing Zone in which the surface-hardened briquettes are subjected in a mass to a slow tumbling action so that they roll upon each other while at the same time subjecting them to the' same gases used in the high heat chamber but at a lower suitable carbonizing temperature for a suflicient period until they are rendered smokeless and possess suicient rigidity of structure to withstand handling and transportation and maintain their form after ignition and while being consumed.

The invention also contemplates the provision of apparatus whereby the heated briquettes after they have passed through the carbonizing Zone are brought into intimate contact with the fuel to be briquetted before the latter enters the mixer for the purpose of cooling the briquettes sufficiently so that they may bel safely stored and at the same time preparing the fuel for use in the making of raw briquettes.

Other objects and advantages will appear from the following description taken in connection with the accompanying drawings which illustrate the invention without defining its limits. In said drawings, Fig. 1 illustrates a diagrammatic elevational view of the entire apparatus, partly in section; Fig. 2 is a plan View of the apparatus shown in Fig. 1; Fig. 3 is a diagrammatic elevational view of the briquette conveyor, I5 looking from the left side of Figs. 1 and 2; Fig. 4 is a similar View of the coal fines conveyor 26 viewed from the right side of Figs. 1 and 2, and Fig. 5 is a similar view illustrating the operation of the coal fines conveyor 39 viewed from the right side of Figs. l and 2.

In connection with these drawings it is to be presupposed that briquettes composed of finely ground fuel, such as coal fines, and suitable bind- 5 ing material, such as pitch or Bunker C fuel oil, and shaped and compressed in a briquetting press `(not shown), are being delivered with machinelike regularity to a drag-chain conveyor l. The briquettes are conveyed by this conveyor from the w briquetting press to a preheater chamber 2 as shown in Figs. 1 and 2. The bottom of the end portion of the conveyor trough 3 which extends over the entire width of a chain grate 4 in the ,1 preheating chamber 2, consists of a gate 5. The "'15 design of the gate 5 is such that it may be adjusted to any angle necessary to cause the briquettes in the conveyor I to be deposited upon the chain grate 4 as a single layer in such manner ,0 that the individual briquettes are substantially out of pressure contact with one another.

The chain grate 4 is endless and acts as a conveyor, conveying the uncarbonized briquettes distributed thereon as a quiescent single layer 5 through the preheater chamber 2. As thebriw quettes are distributed on the chain grate 4 substantially out of pressure contact with one another heat in the chamber 2 will envelop the briquettes uniformly and each will receive like 30 treatment in their passage through the preheater chamber 2. The chain grate 4 is supported at each end by roller bearings 6 and the upper side, upon which are distributed the raw briquettes, is supported in a horizontal plane for substantially g3g, its entire length by a roller chain 'l which acts as a roller bearing. The roller chain 'l is interposed between the chain grate 4 and a supporting track 8. The speed of the chain grate may be varied by adjusting the speed of the driving mechanism 4o (not shown) but is preferably such that each individual briquette will remain in the heating chamber for a period suflicient to surface-harden such briquette. The time of treatment of the briquettes in the preheater chamber 2 will vary 45 depending upon the particular kind of fuel and .binder usedin making the briquettes and the variation of temperature conditions in the chamber 2.

For the heat treatment of the briquettes a 50 Stoker-fired furnace 9 contained in a separate chamber furnishes sufficient heat of suitable uniformity for the entire carbonizing operation to which the briquettes are subjected in their passage through the entire apparatus, as shown in 55 Figs. 1 and 2, from the point of introduction to the point of their discharge. Air is supplied to the furnace 9 through a forced draft inlet I0.

The temperature of the incoming gases passing from the furnace 9, through the connecting passage II, and into the preheating chamber 2 where they come into contact with the single layer of raw briquettes on the chain grate 4 in the preheater chamber 2 is relatively high, being approximately 2000 F. This approximate temperature is readily maintainable by the employment of a thermostatic control (not shown). As the temperature of the briquettes when they leave the briquetting press is comparatively low, not e-xceeding approximately 200 F., it is apparent that, as they are discharged from the drag-chain conveyor I into the preheater charnber 2, they will be at once exposed to a great difference in degree of temperature, said te-mperature being the highest that the briquettes will encounter during their passage through the apparatus. The result of submitting the raw briquettes to this sudden and substantially great difference in temperature is to quickly surfaceharden the briquettes uniformly over their entire surface without affecting the remainder of the briquette so that they may be successfully passed through the next succeeding operation notwithstanding that the inne-r portions of the briquettes are still in a soft condition. This result is most effectively accomplished by applicants device inasmuch as the briquettes are individualized on the chain grate in such manner thatthey are not in pressure contact with one another for if they rested one upon the other as they do on the cross conveyor I, the heat would not envelop the briquettes uniformly and they would be soft and misshapen at their points of pressure contact upon their discharge from the preheating chamber 2.

The surface-hardened raw briquettes are discharged by the chain conveyor 4 upon an inclined surface or wall I2 formed in the discharge end of the` heating chamber 2 which conducts the briquettes as a mass to one end of a rotary carbonizer I3. The inclined wall I2 provides a smooth connecting guideway for the briquettes between the time they leave the chain grate 4 and their entry into the rotary carbonizer I3. The temperature of the briquettes leaving the preheater 2 is approximately 950 F. while the temperature of the furnace gases leaving the preheater 2 is about l200 to 1400 F., say 130()o F. for example, at the inlet end of the rotary carbonizer I3. The rotary carbonizer I3 may be a tube approximately four feet in diameter arranged to be slowly revolved by mechanism (not shown) at a rate of about 1/4 R. P. M. In this rotary drum I3 the briquettes are rolled upon each other, that is, subjected in a mass to a slow tumbling action, being in this way uniformly exposed to the high temperature furnace gases which pass from the preheater 2 into the drum I3 until at the discharge end of the rotary drum I3 the carbonizing gases are approximately 800 F. while the temperature of the briquettes is about 700 F. The rotary drum I3 is inclined so that the rotation of the drum causes the briquettes to travel lengthwise thereof while being gently agitated together in a rotary motion and the inclination is such that the briquettes are maintained in the drum for approximately fteen minutes, or sufcient time to absorb the necessary heat from the furnace gases so that they are suitably carbonized. The

degree. of inclination of the drum I3 can be varied to lengthen or shorten the time for the briquettes to pass through the carbonizer drum I3 according to the particular nature and constitution of the briquettes. The elevated end of the drum I3 is so mounted with respect to the discharge end of the preheater chamber 2 that a tight fit is provided therewith thus preventing leakage of the furnace gases and the entry of oxidizing air and temperature loss at this point. If desired, the preheater may be` wider than is shown in the drawing and a plurality of drums may be used.

The operative rotating speed of the drum I3 is made extremely low in order to eliminate the abrasive action on the briquettes otherwise occurring in this part of the apparatus. If in connection with the particular type of briquettes that is being made or carbonized, too much abrasion should manifest itself the speed of rotation is reduced and the inclination increased.

After the briquettes have passed through the drum I3 they have been almost completely carbonized and therefore rendered smokeless and, by reason of the antecedent series of steps, their shape has been preserved and their strength greatly increased. In order, however, to store the briquettes safely it is important that their temperature, throughout of the entire mass, should be reduced to a. point at which the briquettes will be unlikely to catch are while in storage. Quenching with water while very effective as a temperature reducer to below the critical point is manifestly undesirable for many reasons. Atmospheric or forced air cooling are expensive in operation and uncertain. To meet the necessary conditions the apparatus now to be described was devised and found to be 100% effective, inexpensive and profitable. Speaking generally, the hot carbonized briquettes leaving the c-arbonizing drum I3 are first brought into intimate uniform contact with the fuel that is to be briquetted, such as coal fines, which are on their way from their place of storage to the mixer from which the briquetting press draws its supply. Such coal fines are naturally moist depending upon humidity, precipitation, length of time in storage, etc. At any rate, they can be depended upon to have a moisture content of at least 15%. These moist coal fines are fed into a conveyor I5, by a scraper conveyor I4 from an outside source of supply as shown in Figs. 2 and 3. The conveyor I5 which is in the form of a gravity discharge bucket elevator comprising chains I6 which carry buckets I1, as shown in Fig. 3, passes below the discharge end of the carbonizing drum I3 and moves over a plate I8 upon which is discharged the hot briquettes from the drum I3. As the buckets I'I move over the plate I8 in the direction of the arrow shown in Fig. 3, they pick up the hot briquettes and subsequently the coal fines ldeposited on said plate by the scraper conveyor I4. The buckets I1 carrying the hot briquettes and coal fines pass around a roller I9, are elevated to a height slightly greater than that of the chute aperture 22, and after passing over a roller 20, deposit their contents on a plate 2I and also advance the mixed briquettes and coal fines along the plate 2l to the chute aperture 22 where they are dumped indiscriminately into such chute and thence into the elevated end of a rotary drum or cooler 23. In the cooler 23 the wet coal fines and hot briquettes are now caused to intermingle thoroughly with each other by the rotary action of Athe cooler unit 23, the moisture evaporated from the coal fines, by the heat of the briquettes, being carried away into the stack housing 24 by a current of air produced by a fan 36 and passing counter-current to the flow of the briquettes and coal fines through the cooler 23. The lower end of the cooler 23 comprises a separating chamber in the form of a screen 25,*as shown in Fig. 2, through which the dried heated coal fines are discharged into a suitable conveyor 2B, while the briquettes substantially free from the screened lines, and' now having a uniform temperature of approximately 130 F., slide over a spout 21 into suitable vehicles or conveyors by which they are brought to storage or shipped.

The coal fines discharged into the conveyor 2B may be conveyed directly to the mixer or a place of storage or in order to effect economy in the operation of the apparatus, may be brought by further heat treatment to a still higher temperature using the hot g-ases discharged from the carbonizer drum I3, in those cases where a binder is used whose melting point is above ordinary temperatures. For instance, if a binder such as Bunker C fuel oil, which is uid at or-` dinary temperatures, is used, the drying operation in the cooler 23 is suflicient to prepare the coal fines for making raw briquettes and the coal fines may be conveyed directly to the mixer or a place of storage. However, if a binder, such as pitch, which has a melting point in the neighborhood of from 175-250 F., is used in making the briquettes, heat must be supplied in order to obtain a proper intermixture between the binder and coal fines. To meet this condition, the coal nes which have a temperature of approximately 130 F. when they leave the cooler 23 are transferred to a rotary conditioning unit 33. In this case, a conveyor similar to the conveyor I5 is used and comprisesv chains 28,' carrying buckets 29 as shown in Fig. 4. The dried and heated coal nes which are discharged by the cooler 23 on a plate 30 are picked up by the buckets 29 as they move over the plate 30, elevated to a height slightly greater than that of the chuteV aperture 40 and deposited on a plate 3|. The buckets 29 in moving over the plate 3| advance the coal fines along the plate to the chute aperture 40 where they are dumped into such chute and thence into the elevated end of the rotary conditioning unit 33, through which in the opposite direction pass the furnace gases from the furnace 9 after they have done their work in the preheater 2 and in the carbonizer drum I3 and where they still have a temperature of 800 F. The coal fines entering unit 33 have a temperature of about 130 F. which will be raised to about 250 F. as they pass through unit 33 while the exhaust gases from the drum 1 entering the unit 33 at about 800 F. are discharged into the stack 34 at approximately 300 to 400 F. A fan 35 is provided to maintain the proper draft requirements at the exhaust stack 34. The coal nes which thus have been heated to 250 F. can be directly used in the mixture as a source of heat to bring the binders into proper temperature and plasticity with respect to the coal nes with which they are to amalgamate thereby effecting considerable economy in their part of the operation.

The hot coal fines discharged from the unit 33 are then preferably transported by the bucket elevator which is generally designated by the reference character 39 in Figs. 1 and 2 of the drawings and comprises chains 35a, buckets 36a, plate quired in the mixer to keep the briquetting press suppliedwith mixed material at the rate at which the press delivers briquetted product to the conveyor I. It will be noted that proceeding in this manner there will be ample moist coal nes fed vto the hot briquettes entering the cooler 23 to effect the necessary cooling of the briquettes in that unit. When starting operations after a shutdown, -or new installation, heat is started in the furnace 9, coal lines are fed into the elevated end of Yunit 33 or conveyed there if desired by elevators I4 and I5, unit 23, and elevator 26, the fines being in this way dried and preheated for the mixing operation.- After sufficient amounts of coal nes have been mixed with the binder to start supply- `ing the press for continuous operation, the press begins its work, delivering thev raw briquettes to conveyor I and in a very short time the entire apparatus shown in the drawings will function automaticallyand normally in the manner hereinabove described.

We claim:

` l. In an apparatus for carbonizing raw bri-' quettes, in combination, a heat producing unit, a briquette hardening chamber having an inlet-end and an outlet end and being protected against free admission of air, a traveling grate positioned in said chamber and adapted to convey the raw briquettes delivered at the inlet end of said chamber quiescently therethrough to the outlet end thereof, a flue 'connecting said heat producing unit with said chamber and arranged to direct the high temperature combustion gases from said unit upon said grate at the inlet end of said chamber, means for conveying the raw briquettes to the inlet end of said heating chamber, and sepayrate distributing means at the inlet end of said heating chamber cooperating with said conveying means arranged to deposit the delivered raw briquettes upon said traveling grate just prior to their exposure to the full force of the incoming gases, said distributing means being adapted to arrange the briquettes transversely upon said grate as a single layer and substantially out of pressure contact with each other so that the briquettes will be subjected uniformly to the intense heat in said chamber during their passage therethrough.

2. An apparatus for carbonizing raw briquettes such as set forth in claim 1, in which the traveling grate is of the endless conveyor type and is positioned longitudinally in said heating chamber and the distributing means overlays the traveling grate adjacently to the discharge end of the flue and is adjustable to control the rate of feed of the raw briquettes upon said traveling grate.

3. In an apparatus for carbonizing raw briquettes, in combination, a heat producing unit, a briquette hardening chamber having an inlet end and an outlet end, a traveling grate positioned in said chamber and adapted to convey the raw briquettes delivered at the inlet end of said chamber quiescently therethrough to the outlet end thereof, a flue connecting said heat producing unit with said chamber and arranged to direct the high temperature combustion gases from said unit upon said grate at the inlet end o-f said chamber, means for conveying the raw Cai briquettes to the inlet end of said heating chamber, separate distributing means at the inlet end of said heating chamber cooperating with said conveying means arranged to deposit the delivered raw briquettes transversely upon said traveling grate in a single layer and substantially out of pressure contact with each other just prior to their passage beneath the discharge end of the flue, and a carbonizing chamber communicating with the outlet end of said heating chamber and arranged to receive the high temperature combustion gases directly after they have been passed thro-ugh said heating chamber and being adapted to subject the briquettes discharged from said heating chamber to a slow tumbling action so that the briquettes are gently agitated together in a mass in said carbonizing chamber.

4. In an apparatus for carbonizing raw briquettes, in combination, a high heat producing unit, a preheating chamber having an inlet for raw briquettes and an outlet for briquettes after treatment in said chamber, the chamber being protected against free admission of air and arranged to receive high temperature combustion gases at the briquette receiving end thereof, a conveying device in said preheating chamber adapted to convey the briquettes quiescently therethrough, means adapted to convey raw briquettes to said preheating chamber, a device at the discharge end of said conveying means arranged to deposit upon said conveying device the raw briquettes carried into the chamber by said conveying means, a carbonizer having connection with the outlet end of said preheating chamber and arranged to receive the high temperature combustion gases after they have passed through said chamber, a cooler unit, conveying means at the exit end of said carbonizer adapted to deliver the hot carbonized briquettes to said cooler unit, means to deposit the fuel to be briquetted with said hot carbonized briquettes, said cooler unit retaining the carbonized briquettes and the fuel to be briquetted in heat exchange relation for a sufficient length of time to materially cool the hot briquettes and to raise the temperature of the fuel, means to separate the cooled briquettes and heated fuel, a rotary unit, and means to transfer the heated fuel to said rotary unit, said unit being arranged to receive the hot combustion gases after they have passed through said carbonizer in order to further raise the temperature of the fuel to be briquetted.

5. In an apparatus for carbonizing briquettes, in combination, a heat producing unit, a preheating chamber protected against free admission of air and arranged to derive heat from said unit, means to convey raw briquettes to said chamber, a support for the briquettes in said chamber, said support being adapted to convey said briquettes through said chamber, a device at the discharge end of said conveying means adapted to deposit upon said support the raW briquettes carried into the chamber by said conveying means, an inclined rotary carbonizer having substantially air-sealed communication with the delivery end of said chamber, an inclined rotary cooler unit, means to convey the carbonized briquettes -from said rotary carbonizer to said cooler unit, means to deposit the fuel to be briquetted with said carbonized briquettes, said cooler unit retaining the carbonized briquettes and the fuel in heat-exchange relation for a suflicient length of time to materially cool the briquettes and raise the temperature of the fuel, means to separate the cooled briquettes and the heated fuel, an inclined rotary unit, and means for conveying the heated fuel to said rotary unit, said unit being arranged to derive heat from said carbonizer to further raise the temperature of the fuel lto be briquetted.

6. In an apparatus for carbonizing briquettes, in combination, a high heat producing unit, a preheating chamber protected against free admission of air and arranged to derive the high heat from said unit, means to convey raw briquettes to said chamber, a support for briquettes in said chamber, means at the discharge end of said conveying means and adapted to deposit the raw briquettes on said support in a single layer, means for causing said support to convey said briquettes quiescently through said chamber, an inclined rotary carbonizer, the higher end thereof having a relatively air-sealed connection With the delivery end of said chamber and arranged to derive heat therefrom, a rotary cooler unit, means to convey briquettes from the delivery end of said carbonizer to said cooler unit, means to convey the fuel to be briquetted from a place of storage to said -cooler unit, said cooler unit holding said hot briquettes and fuel in heat-exchange relation for a sufficient length of time to materially cool the briquettes and to raise the temperature of the fuel, means to separate the cooled briquettes and heated fuel, a rotary heating unit connected with the exit end of said carbonizer and arranged to derive. heat therefrom, means for conveying the heated fuel to said heating unit to further raise the temperature of said fuel, and means to transfer the fuel delivered by the heating unit to a place of storage.

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