US1893417A - Briquette - Google Patents

Description

l Jan. 3, 1933. G, KQMAREK'ET AL 1,893,417

BRIQUETTE Filed July 16. 1926 2 Sheets-Sheet l ple/Ee.

Coon/v6 CHMBEE INVENTOR a/sTav /fomarek A oRNEY.

i BY @EMM/N6 Jan. 3, 1933. G. KOMAREK E1' AL BRIQUETTE 2 Sheets-Sheet 2 Fed July 1e, 1926 I N VEN TOR.

Patented `lan. 3, 1933` UNITED STATES; PATENT OFFICE GUSTAV KOMABEK, F CHICAGO, ILLINOIS, AND GEORGE MACPHAIL AND CHARLES CORYELL, OF BAY CITY, MICHIGAN BRIQUETTE Application led July 16,

This invention relates to fuel briquettes. Tt is the object of theinventionto afford a novel fuel briquette having a relatively greater volatilecontent than it has heretofore been t; possible to store in a smokeless briquette.

The history of the art of briquetting is full of attempts to obtain so-called free-burning, smokeless briquettes, but so' far as we are aware none of the prior art exhibits a brilo quette which achieves the result or has the properties' and possibilities of our free-burning, smokeless briquette.

The great problem in briquette manufacture is to get a relatively strong briquette which is smokeless and which at the same time is a free-burning fuel. One of the difficulties met with in briquette manufacture is smoke, rupture of the briquette undergoing the heat treatment, and disintegration of the briquette due to improper physical structure.

It is recognized that smoke is ordinarily produced by the hydro-carbons that are driven oifthe fuel at low temperatures. These hydro-carbons have been driven off before they have had time to be broken up and be burned and form the soot and smoke that is so objectionable. In order to avoid this smoke,

it has been the custom in briquette manufacture to reduce the volatile contents of the briquette to a relatively low point, such as 21/% and 3%, which has been recommended in a number of prior processes, but so far as we are able to ascertain, about 5% is the highest that is recommended in any prior disclosure.A

Fig. 1 is a diagrammatic view or flow sheet of the process.

Fig. 2 is an enlarged sectional view of a carbonized briquette formed in accordance with the present invention, and showing the carbonized outer shell and the relatively unearbonized inner shell.

We propose to start with a briquette which has a relatively greater volatile content than has ordinarily 'been handled in briquette making'.- This we do by using a large bituminous ratio of approximately or more comminuted fuel, and starting with this in the raw condition; that is, not subjecting it to a preliminary distillation before it is -50 briquetted as is recommended by a number 192s. serial No. 122,867.

of prior inventors. This is then subjected to operations which are fully described in our co-pending application on the method, Serial No. 122,868 vfiled July 16, 1926.

` The process, by reason of utilizing the gases driven oft' 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 itto, say, suchiineness that it will pass through a 10-20 mesh screen. The same operation is performed on the bituminous slack, although this may be slightly liner. This circumstance, however, being rather accidental than intended. These degrees of fineness are in no sense mandatory, but are simply given as'directory achieves good results.

It will also be understood that froma of what we broadstandpoint other non-coking fuels such i as charcoal, coke breeze or other carbonaceous non-caking substances can be used in place of' the anthracite. The non-caking ground and dried fuel is then mixed with the caking ground and dried fuel. At this point the b inder can be introduced. We find 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. The final binder is the bituminous element itself whenl it has vbecome coked. We find that the sulphite liquor should be approximately 8 or 9% of the total mixture7 where the liquor is itself 50% 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 fluxer is any suitable mechanism through which the mixture, 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 fuels or sulphite to the mixer and then to the fluxer. 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 and knead the mass.

The mixture leaves the luxer 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 zone of approximately 200 Fahrenheit, to lzones which gradually increase to approximately 600J 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 then pass from the dryer conveyer onto a series of conveyers through a preliminary distillation chamber where the temperature is gradually raised to approximately 1100 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 combustion, and it has stack connections with a rotary kiln about to be briquettes reach a temperature of approximately 650o F., they will ignite and the gases being driven off will .furnish the necessary heat to raise the temperature of the briquettes to the desired coking point. This temperature of approximately 1100 F., and the time interval, is somewhat less than recommended in a good many of the patents of the prior art. The result is that only the exterior of the briquettes is carbonized. The briquettes remain in the preliminary distillation charnber from Sto l5 minutes, depending upon the original volatile content of the briquettes; then they pass onto a conveyer which takes them through a cooling chamber where the temperature is very much reduced. We believe that the temperature of the briquettes is about 800 F. As they reach the conveyer in the cooling chamber, they then gradually cool down to approximately 250. However, at this point the briquette has not been sufdescribed. When the' ciently carbonized to give it the greatest possible strength, nor to eliminate sufficient volatile vpercentage 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 fortiies 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 heat-ed from 1000 to 1400 F. The briquettes remain in the kiln about 8 to l0 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 theyv are loaded on conveyers in the preliminary distillation chambers.`

This kiln is provided with plenty of air, and

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 lnd that it is desirablenot 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, itis 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'irst 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 chamber may/ be very much larger. Hence, if too severe a combustion is set up in the rotary kiln, the impinging of flames and gases will be too severe on the briquettes.

We believe'also there is novelty in the pre. liminary heating step when combined with the coking step, for coking the bituminous ingredients, especially in handling fuel mixtures which have a relatively high voltile content. It has been quite generally recognized in this art that the coking step is liable coking coal down to such a ratio as to eliminate the trouble.

We overcome the diiiculty 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 5 utilizing a bituminous content up as high as or more, if this is desirable. We utilize a preliminary heating step 'to gradually drive oli' 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 briquettes. This is especially true in a briquette that isipassing through the evoking 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 hav-n ing the intervening cooling step to harden thel shell of the briquette.

An example ofa briquette, regarding which an analysis has been made, is one containing 65% anthracite and 35% bituminous West Virginia coal; vthe anthracite had 10% volatile content and thebituminous about- 34%. This made a briquette with a total volatile content of about 17.9%. After going through the first distillation, there was left 13.3% volatile content, and after the second distili lation 8.9% volatile content.

A second example: 50% anthracite coal, 50% West Virginia bituminous coal, each having the same volatile content asin 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%.

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-eighths inch of the briquette had an average volatile content of 6.17%, while the extreme center had a volatile content of 12.1% with some graduations, of course, intervening between the center and the outer shell.

The novelty of our briquette we believe resides in the character of the briquette, name- 6 the original content of the raw fuel and con- This gave a total volatile content of 28.8%; l

ly: one in which the exterior of the briquette.

carbons are broken up by the heat into hydrogen and carbon monoxide, both of whichare very oxidizable gases. These gases immediately combine with the oxygen and are burned and consumed instead of passing oil? in the form of smoke.

Tt will be apparent that the real novelty of our briquette resides in the fact that although it has a high volatile content it is nevertheless smokeless, due to the fact that the high volatile content is the' residuum after a veryy large volatile l-content has been driven oli', which includes the smoke producing hydrocarbons This is the novelty of the briquette structure on the outside. VOn the inside a very much greater volatile content is had,

'andthis is rendered innocuous so far as the smoke nuisance is concerned by reason of being encased inV the interior. These two factors, to wit: the reduction of the Volatile content from an originally high volatile fuel,-

and second, the imprisoning of a still greater volatile content in the core of the briquette,

are factors which afford abriquette of ex-l tremely high volatile content, yet which to all intents ,and purposes is smokeless. This we believe makes a much more valuable fuel f' than has heretofore beenaforded. It has long been appreciated that a free-burning briquette is desirable but at the same time it has been necessary to keep down the volatile content in order to avoid the smoke. l/Vhen the volatile content is low, as proposed-in the v prior art where 21/2%, 3and at the most 5% is recommended, it will be obvious that the free-burning properties are not as great as where there is a lar er volatile content in thel ways already desci ed, and consequently we lave not only a smokeless free-burning briquette but one which burns with a relatively long flame and which has a greater number of heat units due to the retention of the high volatile content.

Q This we believe affords a fuel which is entlrelv novel and which is defined in the claims hereinafter following:

l. A new fuel briquette comprising com-- minuted bituminous and anthracite coal in lwhich the anthracite coal had a combustible volatile content of approximately 10%, and in which the bituminous element had a combustible volatile content originally approximating 34 to 38%, the said two kinds of fuel having been mixed together and carbonized to have an outer shell with a volatile content in theneighborhood of 6% and the volatile content at the centerl of the core of approximately 12% and including smoke-producing hydrocarbons.

ica

2. A new free-burning smokeless fuel briquette consisting of a mass of comminuted coking and non-coking coal in which the noncoking coal had a relatively high original 5 combustible volatile content, and in which the bituminous coal had a combustible volatile content of over 30%, the said two kindsrof fuel having been mixed together and carbonized to have an outer shell with a volatile content in the neighborhood of 6%, the combustib-le volatile content at the core of the briquette being approximately 12% and including smoke producing hydrocarbons.

In testimony whereof we have aixed our 15 signatures.

CHARLES CORYELL. GEORGE MACPHAIL. GUSTAV KOMAREK.

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