US1893555A - Method of manufacturing briquettes - Google Patents

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Ji111910, 1933- G. KOMAREK E'r AL I 1,893,555

METHOD OF MANUFACTURING BRIQUETTES Filed July 16, 1926` Patented Jan. 10, 1933 UNITED STATES PATENT@ OFFICE GUSTAV KOMABEK, OF CHICAGO, ILLINOIS, GEORGE MACPHAIL AND CHABL CORYELL,

OF BAY CITY, MICHIGAN METHOD OF :MANUFACTURING BRIQUETTES Application illed July 16,

This invention relates to a method of making fuel briquettes. It is recognized that briquettes have heretofore been made from a mixture of anthracite and bituminous coal which has been coked by heating the same to relatively high temperatures. However, we believe that our improved method is entirely novel and results in a briquette which has entirely novel properties.

It has been proposed in the antecedent art to briquette mixtures of anthracite and bituminous comminuted coal, but so far as we are aware, the processes have been carried on in quite a diierent way. It has been recognized that where there is a large percentage of bituminous element a very serious problem of rupture of the briquettes is presented. It has heretofore been proposed to obviate this difficulty by reducing the volatile content of the fuel by a preliminary distillation to from 11 to 17%, then briquette the fuel and coke the briquette in a retort, where the volatile products are driven o' and recovered and the residuary volatile products are reduced to approximately 21/%. It has also been proposed tomix anthracite and bituminous comminute'd'ffuel with a dry binder, compress it into briquettes and then coke the briquette at such a heat and for such a length of time as to reduce the volatile content to about from 2 to 3%. It is found advantageous in this process that the bituminous ingredient be given a preliminary distillation before the mixture is made.

Again, it has been proposed to mix a percentage of about to 30% of coking coal with anthracite or non-coking coal and coke the same at a relatively low temperature in a non-oxidizing atmosphere under such con-A ditions as to leave a residuum of about 5% volatile products in the briquettes. It is recognized in this method that if the coking coal percentage is greater than 25 to 30%,.diiculties will be met with in the rupture of the briquette.

Our improved method dilers radically from these prior methods, which appear to be the closest approach of the known art, by reason of employing two distinct distillation steps after the briquetting of the 1926. Serial No. 122,868.

fuel. It also differs from the prior art in burning the hydro-carbons driven olf from the briquettes themselves for the purpose of coking and driving off the volatile products of the briquettes.

This new process, when carried out under the approximate conditions as to heat, time, etc., hereinafter to be detailed, results in a briquette which we believe to be entirely new, and which has rather unusual properties. The briquette can be made from a mixture having a large percentage of bituminous coal or coking coal Without the necessity of rst distilling the raw coal. The briquette finally produced is smokeless and yet has a very high volatile content, reaching more than double vthe volatile content` of anything proposed in the prior art in the way of a smokeless briquette. The reason for this is that the briquette, by reason of the special process which we employ, can loe made from coals having a large percentage of volatile products, and this manufacture can take place without the rupture of the briquette. The smoke producing series of hydro-carbons, which are those volatile products that are driven off at the lower temperatures, can all be driven oliil from the exterior of the briquette, and still leave on the exterior of the briquette a relatively high content of volatile products, none of which, however, are smoke-producing hydro-carbons. On the interior of the briquette which is not materially carbonized, a very much higher percentage of volatile content remains, approximately double that on the exterior. However, the worst of the smoke-producing hydro-carbons have been driven out of the interior. There are, however, no doubt, left in the interior of the briquette hydro-carbons which if not located at the interior would result in smoking. However, the briquettes being very strong and not easily fractured or ruptured, this high-volatile-content core will go through combustion with a production of practically no appreciable smoke. This is due to the fact that the core containing the high volatile content is encased in a shell that approximates three-eighths of an inch, which is carbonized and in which the volatile -vzo .and dried fuel vis then mixed content has been so reduced as to eliminate all the smoke formingl ingredients. Whatever smoke forming hydro-carbons remain in the `core When the fuel approximates its raw state have to pass through an intensely hot shell. When the briquette is under combustion, in passing throughv this shell, these hydro-carbons are completely consumed. T hat is to say, the intense heat of the outer shell causes the hydro-carbons to be broken up into several gases, such as hydrogen and carbon-monoxide. Bot-h of these gases are extremely oxidizable, consequently they both unite with oxygen and burn without appreciable smoke.l This gives a briquette which, is not only free-burning, but what appears to be a desideratum in this art: a smokeless, free-burning briquette of the long flame type, due to the larger percentage of volatile products under conditions which insure the complete combustion of all the smoke-producing hydro-carbons remaining in the briquette.

The figure is a diagrammatic view of the processor what is sometimes called a flow sheet. The process, by reason of utilizing the gases driven olf the briquettes to furnish the heat energy, is extremely economical. There are various ways that our improved process may be practiced, but we find that advantageous results can be obtained by taking the anthracite culm or silt as it arrives from the mines, passing it through a dryer and then grinding it to, say, such fneness that it will pass through a 10-20 mesh screen. The same operation is performed on the bituminous slack, although this may be slightly finer. This circumstance, however, `being rather accidental than intended. These degrees of iineness are in no sense mandatory, but are simply given as directory of what we find achieves good results.

It will also be understood that from a broad standpoint other non-coking fuels such as charcoal, coke breeze orl other carbonaceous non-coking substances can he used in place of the anthracite. The non-coking ground with the coking ground and dried fuel. At this point. the binder can be introduced. We ind that sulphite liquor which has been quite commonly used heretofore in the art as a binder, is very good for this purpose. However, We employ it solely as a temporary binder. binder is the bituminous element itself when it has become coked. We find that the sulphite liquor should be approximately 8- or 9% ofthe total vmixture wher'e the liquor is itself solids and 50% Water;. that only 7 to 8% is required where the percentage is 55% solids and 45% `water.

We introduce the sulphite liquor in this somewhat concentrated form, either in the mixer or in the fluxer. The iiuxer is any suitable mechanism through AWhich the mix- The final ture, together with the binder, passes and is stirred and kneaded to thoroughly spread the binder over the fuel particles. It Will be understood that suitable automatic machinery and conveyors can be utilized to carry the vfuels or sulphite to the mixer and then to the fluxer. A fluxer which We find advantageous is one that has a plurality of shafts with arms which have intersecting paths of travel which are calculated to completely stir andknead the mass.

The mixture leaves the fluxer and then passes into the briquette-forming apparatus, which may be a press but is preferably a series of suitable revolving mold Wheels. The thus formed briquettes, bound together by the temporary sulphite liquor binder, are then passed by a suitable conveying apparatus to a preliminary heating chamber, Where they remain about 10-15 minutes and are gradually raised in temperature by passing from an initial heat zonel of approximately 200 Fahrenheit, to zones which gradually increase to approximately 600o F. This affords the necessary heat to cause the evaporation of all the moisture which obtains in the briquette, due to the Wet sulphite temporary binder. With a gradual increase in heat the moisture is caused to be gradually driven off instead of being quickly converted into steam that becomes pocketed or trapped in the briquette and explodes, rupturing the briquette, as is the case Where briquettes are subjected directly to a high coking temperature. It is not intended that any substantial part of the volatile contents of the .fuel should be driven off in this preliminary heating operation.

The briquettes Vthen pass from the dryer conveyer onto a series of conveyers through a preliminary distillationchamber Where the temperature is gradually raised to approximately 1100o F. It is preferable to use a number of successive conveyers as this tends to turn the briquettes and yet does not subject them to the rough treatment of a rotary kiln. This preliminary distillation chamber is freely provided with air for combustlon, and it has stack connections with a rotary kiln about to be described.. When the briquettes reach a temperature of approximately 650 F they Will ignite and the gases being driven olf will furnish the necessary heat to raise the temperature of the briquettes to the desired coking point. This temperature of approximately 1100o F., andthe time interval, is somevvhat less than recommended art. The result is that only the exterior of the briquettes s carbonized. The briquettes remain in the .preliminary distillation chamber from 8 to 15 minutes, depending upon the original volatile lcontent of the briquette; then they pass onto a conveyer which takes them through a cooling chamber Where the temperature is very much reduced. We bein a good many of the patents of the prior lieve that the temperature of the briquettes is about 800 F. As they reach the conveyer in the cooling chamber, they then gradually cooldown to approximately 250. However, at this point the briquette has not been sufficiently carbonized to give it the greatest possible strength, nor to eliminate suffic ent volatile percentage to make the briquettes smokeless. Nevertheless this partial carbonizing of the briquette and then the cooling has formed a .relatively hard crust on the briquette, which fortifies it against the rougher treatment that it-is now about to receive in the rotary kiln. It is now passed into a rotary kiln which is a long cylinder about 30 to 70 feet long, and with 'one inch or one inch plus inclination for each foot. This kiln rotates from one to two revolutions per minute, and is heated'from 1000 to 1400 l". The briquettes remain in the kiln about 8 to 10 minutes and are rolled over and over again in this kiln, exposing all parts of the briquettes and giving them a uniform carbonization,-something that is not exactly possible where they are loaded on conveyers in the preliminary distillation chambers. This kiln is provided with plenty of air and,'in view of its high heat, the briquettes themselves are burning. Stack connections connect this kiln with the preliminary distillation chamber, and also with the dryer. Hence after the kiln has once been heated up the briquettes themselves afford all the energy necessary to keep the apparatus going. The briquettes now pass out the end of the kiln and are quenched with water.

We find that it is desirable not to try to remove more than 5%'volatile products in the rotary kiln. For instance, if the volatile products left after the first distillation are 17% of the total fuel, it is unwise to try to reduce the volatile total to less than 12% in the second distillation. It is better to do the greater part of the driving off of the volatile products in the first distillation, if this has to exceed 5%. The reason for this apparently is that the dimensions of the rotary kiln are relatively limited while the preliminary drying fchamber may be very .much larger. Hence, if too severe a combustion is set up in the rotary kiln, the impinging of the fiames and gases will be too severe on the briquettes.

We believe also there is novelty in the preliminary heating step when combined with the coking step, for coking the bituminous ingredient, especially in handling fuel mixtures which have a relatively high volatile content. It has been quite generally recognized in this art that the coking step isliable to rupture the briquette., especially where there is a high volatile content. In order to meet this difficulty, some of the processes of the prior art propose to subject the fuel to a reliminary distillation before it is briquetted, While others attempt to deal with the` 50% West Virginia difficulty by keeping the percentage of the coking coal down tosuch a ratio as to eliminatethe trouble.

We overcome the difficulty not by keeping down the bituminous content, for in some localities it is more desirable to use up the bituminous slack than it is to import the anthracite culm. We are therefore able to suit the requirements of such localities by utilizing a bituminous content up as high as or more, if this is desirable. We utilize a preliminary heating step to gradually drive off the moisture inherent in the sulphite binder before the briquettes are subjected to the high coking heat. This causes the steam to be not generated so rapidly as to cause the rupture of the briquette. This is especially true in a briquettethat is-passing through the coking stage under the burden of a heavy volatile content. It is possible to get measurably good results by combining this preliminary heating step with only one distillation carried out over a longer period of time, but We find that we get very much superior results in splitting up the distillation in the way that we have already described, and having the intervening cooling step to harden the shell of the briquette. In view of these measurably good results, we therefore intend in some of the claims to claim the preheating step in connection with the distilling operation whether it is a single distillation operation or divided intoseveral steps.

The character of the briquettes and the nature of the process can be properly understood only by giving a few examples, for instance: We find that 65% anthracite and 35% bituminous West Virginia coal furnishes a total volatile content ofabout 17.9%, the

anthracite having about 10% volatile content and the bituminous about 34%. After going through the first distillation there was 13.3%

volatile content left, and 8.9% content after kiln.

anthracite coal, bituminous coal, each having the same volatile content as in the first example, furnished a mixture with an original volatile content of 22%. This, after the first distillation had 16% volatile content and 11% after the second distillation.

A third example involved 30% anthracite and 20% West Virginia bituminous, and 50% Michigan bituminous non-coking coal, which has a volatile content of approximately 38%. This gave a total volatile content of 28.8%; after passing through the first distillation there was 19.4% volatile content left, and after passing through the second, 14.4%.

Now to show the nature of the briquette A number of the briquettes made in accordance with the first example were analyzed. It was found that the shell or outer three-eights inch of the briquette had an average volatile content of 6.17%, while the extreme center passing through the rotary A second example: 50%

had a volatile content of 12.1%, with some graduations, of course, intervemng between the center and the outer shell. This, of course, gives a `core which has a high volatile content, but which, as explained in the early part of the specification, is permissible because whatever smoke producing hydro-carbons are left are consumed in passing through the very intense heat of the outer shell. On the other hand, the reduction of the hydrocarbons in the outer shell is sufficiently great to eliminate any smoke here. It will also be apparent that in the other examples Where a highervolatile content is started with, greater percentages will be had both on the shell and in the core. These Will vary widely of course, depending upon the character of the original fuel. However, if the volatile content becomes so great as to still comprehend the hydro-carbone that give forth smoke, it is possible to obviate this trouble by altering the heat and'time conditions in the process so as to drive off more of these hydro-carbons and obviate these objectionable conditions.

lNhat We claim is:

1. The method of manufacturing fuel briquettes, which comprises mixing comminuted coking fuel with comminuted solid carbonizable non-coking fuel, pressing same together to form briquettes, then subjecting the briquette to a preliminary distillation of some of the volatile. content followed by a cooling period and then a second separate destructive distillation under agitation.

2. The method of manufacturing fuel briquettes, which comprises mixing comminuted coking fuel with comminuted solid carbonizable non-coking fuel, pressing same together to form briquettes, then subjecting the briquettes to a preliminary distillation to partially coke the coking ingredient, then cooling the hot bri uette and finally subjecting it to a final car onizing step to complete the treatment. 'F

3. The method of manufacturing fuel briquettes, which comprises mixing comminuted coking fuel with comminuted solid carbonizable non-coking fuel,`pressing same together to form briquettes, then subjecting the briquette to a first distillation, then passing the briquette through a very much reduced temperature so as to cool the shell of the briquette, and finally passing the briquette through a rotating kiln where the briquette is further carbonized While being tumbled.

4. The method of manufacturing briquettes, Which comprises pressing into briquette form a comminuted solid carbonizable fuel including a bituminous ingredient, then subjecting the briquette to a preliminary coking operation, then a cooling operation, and then a secondcoking operation.

5. The method of making fuel briquettes, which comprises the pressing of comminuted solid carbonizable fuel into briquettes with Lacanau;A

the aid of a temporary binder, said fuel inquettes, which comprises the pressin of a comminuted solid carbonizable fuel including a coking bituminous ingredient into briquettes, then subjecting the same to a preliminary drying operation to drive off the moisture, then a separate preliminary destructive distillation operation at a temperature of the briquettes approximatin 800 Fahrenheit, and for only sufficient time to carbonize the exterior of the briquette, then gradually reducing the temperature of the briquettes to permit the hardening of the shell, and finally subjecting the same to a second destructive distillation operation for several minutes at a temperature suflicient to effect further positive carbonization.

8. The method of making briquettes for fuel, which comprises the mixing of anthracite culm with a.relatively large proportion of bituminous slack approximating at least 50%, then bri netting the mixture, preliminarily drying t e briquette to expel the moisturc, then subjecting the briquette to a first carbonizing operation followed byK a cooling operation, and finished with a second carbonizing operation.

9. The method of making briquettes for fuel, which comprises the mixin of anthracite culm and bituminous slac addin a' binder, pressing the same into briquettes a r the addition of'a binder, drying the same at a temperature of approximately 200 to 400 degrees F., then preliminarily distilling the briquettes at a temperature of the briquettes of approximately 800 degrees F., then allowing the same to cool down to a temperature of approximately 250 degrees F., then carbonizing the briquettes and agitating them at a temperature of approximately 1000 to 1400 degrees F.

l0. The method of making briquettes for fuel, which comprises the mixing of comminuted solid carbonizable fuel including a bituminous ingredient having a binder, press- Aing the same into briquetteswsubjecting the 11. T e method of manufacturin smoke- 10 less briquettes, which comprises mixing comminuted solid, carbonizable non-coking and coking fuel, briquetting such mixture under conditions that leave moisture in the briquette, then subjecting the briquettes to a preliminary heating operation short of a cokving temperature to slowly dry oif the mois.-

ture, then continuously passing the briquettes througha separate chamber and subjecting them to a cokmg temperature for a length of time suicient to only carbonize and form a shell around the briquette of predetermined depth, reducing the temperature of the bri quette to harden the shell, and finally subjecting the briquette to a second higher'heat to further carbonize said shell.

12. The method of manufacturing fuel briquettes, which comprises mixing coking fuel with comminuted, solid, carbonizable noncoking fuel, pressin same together to form briquettes, then subjecting the briquettes to a travel in a state of substantial quiescence through a preliminary distillation atmosphere where the briquettes are ignited and the temperatureof the briquettes approximates 800 F., then interrupting the burning of the briquettes to form a carbonized shell, reducing the tem erature of the briquettes to toughen the s ell for the next step, and then passing the briquettes through a rotating kiln where the temperature approximates 1400" vxhlle being tumbled to further carbonize said s e 13. The method of making fuel briquettes, which comprises the pressing of comminuted solid carbonizable fuel including a bituminous in ient into briquetteswith a temporary inder, then subjecting the same to a preliminary gradual heating step of approxi- 15. The method of manufacturing briquettes, which comprises the pressing of comminuted, solid, carbonizable fuel including a coking bituminous ingredient into bri-. quettes, preliminarily heating the briquettes -to slowly dry olf the moisture, subjecting the "briquettes to a. coking operation by igniting the briquettes, turning over the briquettes 4so that each side is slightly burned, interrupting the burning and reducing the temperature of the briquettes to harden the crust formed by the cokmg operation, and finally subjecting the briquettes to a second coking operation.

16. The method of manufacturing briquettes, which comprises the pressing of comminuted, solid, carbonizable 'fuel including a coking bituminous ingredient into briquettes, preliminarily heatingthe briquettes to slowly dry off the moisture, subjecting the briquettes to a coking operation by igniting the briquettes, turning over the briquettes so that each side is slightly burned, interrupting the burning and reducing the temperature of the briquettes to harden the crust formed by the cokmg operation, and finally subjecting the briquettes to a second coking operation by ignlting the `briquettes while being tumbled.

17. The method of forming n0nsmoking,`

free burning briquettes, which comprises the pressing of solid, carbonizable fuel including a coking ingredient into briquettes, forming a hard carbonizedshell around the outer surfaces of the briquette by first subjecting the briquette to a preliminary coking operation by i iting the briquettes and interrupting the urning and reducing the temperature thereof at a predetermined time so as to form a relatively thin ca 'rbonized shell, interrupting the ignition for a sufficient period to allow the shell to harden, and then subjecting the briquettes to a final coking operation.

In testimony whereof we have aifixed our signatures.

CHARLES CORYELL.

GEORGEv MACPHA1L-- GUSTAV KOMAREK.

matelyten to fifteen minutes to gently expel the moisture of the binder, then coking the briquettes by subjecting the same to a greatly increased heat by fusing some of the bituminous ingredient, then interrupting the coking step and reducing the temperature of the briquettes to form a shell around each briquette and then subjecting the briquettes to 05 tions with an intervening period of cooling.

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