US1860743A - Briquette and process for making same - Google Patents

Description

Patented May 31, 1932 UNITED STATES PATENT OFFICE GUSTAV KOMAREK, OF CHICAGO, ILLINOIS, ASSIGNOR TO IBERWIN'D FUEL COMPANY OF DELAWARE, OF CHICAGO, ILLINOIS, A CORPORATION OF- DELAWARE IBBIQUETTE AND PROCESS FOR MAKING SAME No Drawing. Application filed June 20,

The present invention relates to fuel briquettes, and has as an object to provide a briquette of improved composition and a new and improved process for the manufacture of briquettes.

An object of the invention is to reduce the formation of dust in the manufacture and handling of the briquettes, and also to improve the briquette for combustion purposes, more particularly by reducing the smoke given ofli' during combustion.

Briquettes are ordinarily made from finely divided carbonaceous material, such as anthracite or bituminous coal, coke fines, or petroleum coke, and an improved briquette composition involvin the use of petroleum coke and other materlal of low volatile con- 1 tent, such as coke fines, is disclosed in my Patent 1,7 96,465, Mar. 17, 1931.

Briquettes of these compositions have one fault in common with coal or coke, namely, the dust which is produced by the abrasion set up in handling. Briquette dust is particularly objectionable, due to the loss of combustible material, and furthermore, because of the binder which makes the dust sticky, and, therefore, more objectionable than dust of ordinary coal or coke.

It is, of course, old and well known to utilize various chemicals for allaying coal dust, and their use is extensively treated in Bulletin 20 of the Bureau of Mines, (Government Printing Oifice, 1911) entitled The Explosibility of Coal Dust. However, so far as I am aware, the use of deliquescent materials 'has heretofore never been extended to briquettes. Their use in briquette manufacture is attended with problems, such as the deterioration of the briquette by the chemicals, which is more serious than any deterioration due to. dust formation.

Briquettes ordinarily comprise the combustible 'mass, such as coal, coke, or a combination of these, and a binder. Binders are of two general classes, namely, (1) those impervious to moisture, such as coal tar pitch and asphalt, and (2) those susceptible to moisture and somewhat hygroscopic, such as sulphite liquor and starch. Y c

When 'either class of binder is used it has 1929. Serial No. 372,545.

onsequently, old and well known processes heretofore employed for allaying coal dust are not practicable, since the heating and drying of thecoal to remove moisture, would at the same time remoil e the hygroscopic material applied to the coa Furthermore, the inclusion of .a deliquescent material in the briquette would, naturally, be regarded as objectionable, for the reason that its hygroscopic action would deteriorate the binder, and, by impairing the adhesive qualities of the latter, break down the briquette. For these reasons any hygroscopically active material heretofore used in the briquettes have been employed for other than hygroscopic action and have been chemically neutralized, thus eliminating any tendency to absorb moisture.

I have discovered that it is possible, and desirable, to use in briquettes a deliquescent material, and particularl a deliquescent salt, such as calcium chloride CaCl magnesium chloride (MgCI or a material such as p'otassium carbonate (K CO These materials by their hygroscopic action improve the briquette, and not only prevent the formation of dust, but also slow down combustion, thereby reducing the amount .of smoke given off.

This retardation of combustion renders neceshygroscopically active. This phase of my invention involves in its applicationi to briuette manufacture particular attention to t e nature of the binder employed. If, in

the briquette, a binder or other material is 1 used, which tends to combine or react chemically with the deliquescent material, then a sufficient amount of such deliquescent materialmust be used over and above that. part which combines with or is neutralized by the binder or any other ingredient, in order that salt, the latter should be used in such an or mixing'operation difi'uses the deliquescent amount, and applied in such a way, as to be free for hygroscopic action. Also it must be employed in the manufacturing process in such a way as not to break down the adhesion of the combustible particles produced by the binder. This may be accomplished by controlling the amount of deliquescent material used, and also by following my improved process, which involves varying the mode of including the deliquescent material or salt in the briquette.

In the manufacture of practically all briquettes the moisture is largely removed from the combustible mass of carbonaceous material before it is mixed with a binder. This mass consists of finely divided material, such as anthracite or bituminous coal; The carbonaceous material is then mixed with a suitable binder, and to this mixture the deliquescent material may be added in dry form, particularly when steam is introduced during the kneading or mixing operation. Such-material as deliquescent salts of the magnesium chloride group,'or of the calcium chloride.

group, have been found very satisfactory.

The steam introduced during the kneading salt through the mass or mix and the briquettes subsequently formed or molded ther'efrom have the salt or' other deliquescent material distributed therethrough. This processhas been found to be very satisfactory when either asphalt, or coal tar pitch binders have been used, and even when a secondary binder is employed, such as sulphite liquor,

starch or bentonite.

calcium or magnesium chloride, or both, is

used, for the reason that the moisture content of. the solution lessens the adhesive effect of the binder. When the deliquescent salt is introdueed' before the briquette is molded, it is preferable to utilize the. material in dry form, particularly if steam or other agents which will dilfuse the material through the mass are employed during the kneading operation.

After the briquette has been formed, or as it is formed, a deliquescent material may be applied to its surface, for instance, by maintaining moist or saturated with the solution, the forming rolls or molds of the apparatus. Such a method has been found useful either in lieu of, or in addition to, the introduction of dry deliquescent material in the mixture. This procedure thoroughly impregnates the surfaces of the briquettes, and it is found there is a penetration for a suflicient depth, thereby rendering the exterior of the briquette hygroscopic.

I have observed that this method, when employed for the application of deliquescent salts, afi'ords good protection and improves the surfaces of the briquettes not only by allaying dust, but also by slowing down combustion. This slowing of combustion is probably due to an increased moisture content; it

renders necessary higher temperatures before there can evolve the smoke-producing volatile gases contained in the binder.

As to the percentage of deliquescent material to be included, these will necessarily vary,

because of the different types of combustible carbonaceous materials employed, and also because of the different binders utilized in briquette manufacture- If the briquette includes either as a binder or for other purposes, a material which is chemically active relativeto the deliquescent material orsalt, then, of course, it is necessary to utilize an amount of the latter suflicient to leave in the completed bri uette a free or available portion of the deliquescent material, i. e., a portion over and above that neutralized by the reactive element in the mix, in order to produce a hygroscopic action.

However, it is preferable to utilize the binder which is chemically'inactive or inert relative to the deliquescent material and to guard against the inclusion of in redients which react chemically with the deliquescent material, and thus counteract its hygroscopic action. A binder such as coal tar pitch or asphalt is of this nature.

- With briquettes of this composition, i. e., those which include an inactive or inert binder and no other elements which chemically modify the deliquescent salt, one percent 1%) of calcium chloride, magnesium chloride, other deliquescent salt will suflice as a deliquescent material content, and will aiford the desired hygroscopic action. Thls content may be obtained by introducmg dry or crystal magnesium or calcium chloride into the mixture, or by surface impregnation of the formed briquette. Orboth modes of application may be adopted.

ThlS amount of calcium chloride 1%) will of the binder, although when a binder such as sulph ite liquor, which has an aflinity for moisture and is itself hygroscopic is employed, it

will be found preferably to utilize the surface the harder coals, which are not so dusty.

the completed briquette is a deliquescentma erable that the deliquescent material should When the allaying of dust is the only consideration, and the surface impregnatlon method is followed, it will be satisfactory 1f about one-eight to 1 quarter percent of terial; but where it is desired to slow combustion and reduce the evolution of smoke during burning, the content of deliquescent material should be higher, and then it is prefbe introduced into the body of the briquette by other means than surface impregnation, either in addition to the surface impregnation or in lieu thereof. It has been found that for improving the combustion and reducingsmoke given off, the content of deliquescent materials of the nature of calcium chloride and magnesium chloride should be in the neighborhood of one percent (1%).

The following will serve as suitable examples of compositions which have been found satisfactory I 1 Per cent Coal 93 Asphalt 6 Calcium or magnesium chloride 1 2 Coal 92 Asphalt 4.- Sulphite liquor 3 Calcium, or magnesium chloride 1 3 Coal 93 Asphalt 5 Bentonite 1 Calcium or magnesium chloride 1 4 I Coal 93 Coal tar pitch 6 Calcium or magnesium chloride 1' C031 93 Goal tar pitch 5 Bentonite 1 Calcium or magnesium chloride 1 In the above compositions the deliquescent salt has been included in dry form, and in lieu thereof by surface impregnation. Also both methods of introducting the deliquescent material have been utilized. That is to say, a portion of the salt has been introduced in dry form and the remainder by impregnating the surface of the formed briquette by an aqueous solution.

It will be understod thatboth magnesium and calcium chloride may-be used at the same time, if desired. The invention is characterized by the use of a coal which has not been treated with hygroscopic material, and from which, on the contrary, the moisture has been removed by drying and heating. Moreover, the invention contemplates the mixing of the coal or other carbonaceous mass with the binder before the deliquescent material isintroduced, so that the carbonaceous material may be subjected to the binder and coated therewith before it is subjected to moisture resulting from the hygroscopic material.

The coal particles are thus treated thoroughly with the binder, and since they are free from moisture, the binder may cause adhesion of the various particles, more effectively than if the moisture content of the coal were high, or artificially raised by applying the deliquescent material thereto before the subjection of the coal to the binder.

In all of the various methods utilized there should be free or available material in the formed briquette. In some processes which involve the baking or coking of the molded briquette, it may be found desirable to impregnate the surface with the deliquescent material in solution after the coking operation.

Obviously, the invention is not limited to the details above set forth, and such variations may be made therein as come'within the scope of the following claims which define the more essential features.

I claim:

1. The method of preparing fuel briquettes which comprises preliminarily drying a carbonaceous material, mixing therewith a binder, adding thereto a deliquescent salt in dry form and in sufiicient quantity to be hygroscopically active, and molding the mixture. i

2. The method of preparing fuel briquettes which comprises prelimlnarily drying a carbonaceous material, mixing therewith a' binder, adding thereto a deliquescent salt in dry form andin sufficient quantity to be hygroscopically active, kneading the mixture, diffusing the salt through the mass by means of steam and then molding the briquette. i

3. The method of preparing fuel briquettes which comprises preliminarily drying a carbonaceous material in finely divided form, mixing the finely divided carbonaceous material with a binder, adding thereto a deliquescent salt in dry form and in sufiicient quantity to be free, whereby to exert a hygroscopic action, kneading the mixture, diffusing the salt by means of steam throughout the mass, molding the briquette and applying a deliquescent salt 'in solution to the surface of the molded briquette.

4. The process of preparing fuel briquettes which comprises preliminarily drying a carbonaceous material in finely divid ed form, mixing the finely divided carbonaceous material, a deliquescent salt and a binder substantially chemically inactive rel ative to the material, whereby the latter may be hygroscopic-ally active, molding the briquettes and applying a deliquescent salt in solution to the surface of the molded briquette.

5. A. fuel briquette. comprising finely divided substantially dry combustible car-- bonaceous material, tabinder, and a deliquescent salt in dry form in sufficient quantity to be hyiroscopically active.

6. briquette comprising carbonaceous material, a binder, and a deliquescent salt coating the surface of the briquette and pencrating-the briquette and extending below the surface thereof, said deliquescent salt being present in suflicient quantity to be hygroscopically active.

In testimony whereof I have hereunto set my hand.

GUSTAV KOMAREK.