US1793833A - Fuel briquette and process of making same - Google Patents

Description

Patented Feb. 24, 1931 PATENT OFFICE nonsnn s. ANDREWS, or BUMSON, NEW

JERSEY; HILAH R. ANDREWS ADMINIS- TBATOR F SAID DONALD S, ANDREWS, DECEASED FUEL BRIQUE'ITE AND PROCESS OF MAKING SAME No Drawing. Application filed April 28,

The invention relates to fuel briquettes fabricated from anthracite culm or fines, an' asphaltic binder and bituminous coal, with or, Without the addition of steam size anthracite, and a process of making them.

In'the preparation of sized anthracite coal for market a considerable quantity of coal is broken into small. particles of various sizes which are not suitable for domestic use. The finest particles are known as culm, fiines or dust,? which is considered waste, and other larger particles are known as steam sizes, and are specifically called, in the order of their size, No. 1 buckwheat, No. 2 buckwheat (also called rice) and No. 3 buckwheat, (also called barley). The steam sizes or buckwheat is used to a considerable extent for steam purposes inthe East, and is burned on the locomotives of anthracite carrying railroads. Both steam sizes and culm have been utilized in making briquettes for domestic use, which have been combined with various binders, including bituminous coking coal, starch, pitch, etc, but all such briquettes have been, much inferior to the coal from whichthey were derived in one or more respects in that they have been of low degradation, possess volatile hydrocarbons which cause too much smoke, or disintegrate readily in the lire box, etc, whichhas prevented their extensive use.

The object of this invention is to produce,

' abriquet-te with culm as the principal ingredient, or culm combined with steam sizes, of improved qualities, that will withstand handling and shipment with small loss in weight that will maintain its integrity until consumed in the furnace, that will be substantially smokeless, and that on the whole 40 will be equal to, or better, in total efiiciency,

than the coal from which it is derived.

I attain these objects by the process now to be described and hereinafter claimed.

I use for the principal constituentofmybri- 4 quette either all culm or culm and steam sizes.

1930. Serial No. 448,163.

Another ingredient is petroleum residuum asphalt or air blown petroleum asphalt, and for my purpose it should be one thathas a melting point between 71 and centigrade, the asphalt of higher melting point being preferably selected for use in making the briqnette during warm or hot weather and one of lower melting point being employed when manufacturing in cold weather. Such petroleum residuum asphalt is well known in the art, and for the purposes of this application it is sufiiciently indentified to those skilled in the art by specifying its melting point. The only other ingredient used is a bituminous coal which has a low content of volatile hydrocarbons, relatively high in fixed carbon and with good coking qualities. Bituminous coals which I have found particularly etficient in my process are Pocahontas and Georges Creek. Low volatile bituminous coal is employed because, being low in volatile hydrocarbons, it is, in combination with the other ingredients, substantially smokeless, and because of its coking quality it serves, in combination with the asphalt, to bind the anthracite particles together and prevents disintegration of the briquette in the lire bed. F or my purpose the low volatile bituminous coal is pulverized preferably to a point where all particles will pass a -1nesh screen, such fine division making it possible to thoroughly disperse it throughout the mass.

Petroleum residuum asphalt is an excellent binder, possessing properties of low degradation and high compressive resistance combined with weathering qualities not approached by any other commercially obtainable binder known at present. But as here tofore employed in briquettes it softened and permitted the briquette to fall apart or the briquette was of inferior structure internally during its passage down through the fire bed and disintegrated to such an extent that there was large loss in unconsumed carbon. Such asphalt has a residual. carbon content of only about 30%, which is insufficient to provide sufiicient coke in the fire to prevent disintegratiori. The use of an excess of asphalt would provide more coke but this is impracticable as such excess would give oii' much smoke and greatly increase the cost of production. For this reason I employ as little asphalt as possible to act as a binder until it .enters the fire bed and use low volatile bi-' contact with the asphalt there shall be retained upon the surface of each individual particle a minimum asphalt thickness. I then take a measured quantity of the fluid asphalt and add it to a measured quantity or" the steam size anthracite while both are approximately at the temperatures stated and mix them thoroughly together, using a quantity of asphalt slightly in excess'of that which will provide a very thin coating to each particle of coal. The asphalt is introduced into the steam size first to prevent the balling or agglomeration which results when asphalt is introduced into fines and which, in turn, necessitates protracted mixing to break up theseagglomerations. I also heat the culm to about the same temperature and after the steam size particles are thoroughly coated I measure a quantity of heated culm, add to it a measured quantity of the pulverized bituminous, and add this mixture to the heated asphalt-coated steam size coal and then thoroughly miX the whole together, thereby thoroughly dispersing the bituminous particles throughout the mass, in which condition one or more particles oi bituminous coal are interposed between adjacent particles of the steam size, which are caused to adhere thereto by'the asphalt coating. While, as stated, the pulverized bituminous and the culm may all be mixed together and added to the asphalt-coated steam size, I have found it preferable instead, to-add onehalf of the culm to the asphalt-coated steam size and thoroughly mix the same before adding the other half of culm mixed with the pulverized.

is imperative that the bituminous be not,

subjected to this primary heating as that would cause combustion of the low volatile constituents. V

In'regard to the quantities of the in- The asphalt is iyeaess' gredients to be used, the quantity of culm and steam size may be greatly varied, but I find it desirable touse not more than about 60% I of the steam size; The quantity of asphalt is kept as low as possible and still provide a 5 practice it has been found that when steam size and culm are-used as the .base there should be used about 5% of as Jhalt and not less 7. V V a than 4%. As above stated the bituminous b8111 em 31o ed to revent disinte ration of 1 .L L the oriquette, enough should be used -LO secure this result, but it more is employed smoke Wlll be produced. I have found that withother ingredients in the proportions stated, not less than about 5% ofthe bitumlnous should be used for the best results. All percentages Therefore, a good stated are by weights. briquette can be madeby using not 1n excess of about 60% of steam size, culmof a percentage vhich together with the steam size will constitute about 90%, asphalt about 5%,

and pulverized bituminous coal about 5%. The best embodiment of my invention which I have up to this time tested consisted of:

v V Per cent team size anthracite about Culm (anthracite) about 45' Petroleum residuum asphalt about 5 Pocahontas (low volatile bitus v v minous) i about 5' In tests to determine the qualities of a briquette made according to the formula above as compared to the coal from which it was derived, the results were as follows:

Briquette Coal from according which it to this was invention 7 derived Degredation 3. 23. 16% Drop test 7. 71% 22. 88% Crushing strain, lbs. per sq. in -2135 1721 Evaporation efliciency 56. 5% 63% Total eflicienoy 96% 82% It appears from the tests made that the only advantage possessed by the original coal over the briquette is a slightly greater thermal eiiiciency, but that'it is inferior in the other respects named. Also it has been found thata fuel composed of 7 5% briquettes made according to this invention witli'25% of stove coal shows a superiority over either briquettes'or coal in length and heat of combustion.

After all the ingredients specified have been'thoroughly mixed together, the mixture is allowed to cool with constant agitation to between 125 and 135 centigrade, when it may be rolled into flat sheets (to be later broken up), or pressed into any desired form.

Vfhile I prefer to use a mixture of steam size andculm as the principal ingredients, I may omit the steam size. In such case the culm and asphalt is heated as above stated, the fluid asphalt is added to the heated culm and thoroughly mixed, after which the bituminous is added and the whole thoroughly mixed. A procedure preferred to the one just is mixed with the steam size, in view of the fact that the particles of culm of a given weight have more surface area than a like weight of steam size, being of smaller size.

In such case if the particles of culm are not too small about 5% of asphalt is sufficient, but if the culm is finely divided the proportion of asphalt should be increased to correspond with the state of division of the culm.

A variation of 5% in the asphalt content will probably freely, heating the culm to approximately the same temperature, adding the asphalt to the culm while so heated and thoroughly mixing the same together, and then adding to said mixture the pulverized bituminous coal and thoroughly mixing the whole together.

2. In a process of making anthracite fuel briquettes from culm, petroleum residuum asphalt and low-volatile bituminous coal in the proportions of about 85% to 90% culm,

5% to of asphalt, and about 5% of pulverized bituminous, the steps of heating the asphalt to a temperature where it flows freely, heating the culm to approximately the same temperature, adding the asphalt to aboutone half of the culm while so heated and thoroughly mixing the same together, and then adding to said mixture the other half of the culm mixed with the pulverized bituminous and thoroughly mixing the whole together.

3. In a process of making anthracite fuel briquettes from steam size anthracite, culm, petroleum residuum asphalt, and low-volatile bituminous coal in the proportions of steam size not to exceed about of culm enough so that culm and steam size together will constitute about 90%, of asphalt about 5%, and of pulverized bituminous coal about 5%, the steps which consist in heating the asphalt to a point where it flows freely, heating the steam size and culm to about the same temperature, adding the asphalt to the steam size while so heated and thoroughly mixing the same together, thenadding'to said mixture a mixture of theculm and bituminous coal, and thoroughly mixing the whole together.

4. In a process of making anthracite fuel briquettes from steamsize anthracite, culm, petroleum residuum asphalt, and low-volatile bituminous coal in the proportions of steam size not to exceed about 60%, of culm enough so that culm and steam size together will constitute about 90%, of asphalt about 5%, and of pulverized bituminous coal about 5%, the steps which consist in heating the asphalt to a point where it flows freely, heating the steam size and culm to about the same temperature, adding the asphalt to the steam size while so heated and thoroughly mixing the same together, then adding about one-half the culm and mixing, and finally adding the other half of the culm mixed with the bituminous, and thoroughly mixing the whole together.

5. In a process of making anthracite fuel briquettes from culm or culm and steam size coal, petroleum residuum asphalt, and lowvolatile bituminous coal pulverized to a point where every particle will pass a l00-mesh screen, the steps of heating the asphalt to a temperature where it will flow freely, heating the anthracite to substantially the same temperature, adding to the anthracite while so heated the freely flowing asphalt and thoroughly mixing the same to form a thin coating of asphalt on the particles of anthracite, and then adding to said mixture a quantity of the pulverized bituminous coal sufficient to form an effective binder and thoroughly mixing the whole together.

6. A fuel briquette having an anthracite base consisting of steam size coal, culm, petroleum residuum asphalt, and low-volatile pulverized bituminous coal in approximately the following proportions steam size coal not to exceed 60% culm enough so that culm and steam size together will constitute about 90% asphalt about 5%; and low-volatile bituminous coal about 5%.

7. The briquette specified in claim 6 in which the low-volatile bituminous coal is pulverized to a point where every particle will pass a lOO-mesh screen.

8. A fuel briquette having an anthracite base consisting of culm, petroleum residuum asphalt, and low-volatile pulverized bituminous coal in approimately the following proportions: culm from to asphalt from 5% to 10% low-volatile bituminous coal about 5%.

9. The briquette specified in claim 8 in which the low-volatile bituminous coal is pulverized to a point where every particle will pass a -mesh screen.

10. In a process of making anthracite fuel briquettes from anthracite, culm, petroleum residuum asphalt and low-volatile bituminous coal in the proportions of about 85 to 90%. ofculm, 5% to 10% of asphalt, and about 57% of pulverized bituminous coal, the steps of combining,- :the anthracite particles with asphalt when both are-at substantially-the temperature of the asphalt in a freely flowing liquid state so as to form a thin coating of asphalt on each particle of-coal, and then adding the bituminous coal and thoroughly mixing the Whole together. 4 v r i Signed by me this 26 day ofApril, 1930. DONALD S. ANDREWS.