US2416476A - Dustless fuel and process for obtaining same - Google Patents

Description

Patented Feb. 25, 1947 DUSTLESS FUEL AND PROCESS FOR OBTAINING SAME Walter M. Fuchs, State College, Pa.

No Drawing. Application June '12, 1942, Serial No. 446,769

2 Claims.

My invention relates to the utilization of coal dusts and fines such as are obtained in modern plant practice of coal cleaning and coal preparation. These ducts and fines find at present no ready market because of their dustiness and bulkiness, and also because of the fire hazard involved in their use. It is the object of the present invention to transform coal dusts and coal fines into a dustless, water repellent fuel. This is accomplished by shaping dusts and fines into small bodies without the use of a binder or any other extraneous carbonaceous material and without the use of heat. The method of manufacture is based on several unexpected observations specified below; it is inexpensive, convenient, and gives a product which is easy to handle, practically free of dust, and attractive to the consumer.

During the last one hundred years, many inventors have attempted the utilization of fine coal by briquetting. As early as 1848, Easby obtained the U. S. Patent 5,739 ,for amethod of converting fine coal into solid lumps. The inventor proposed to take the fine coal and put it into a strong mold of the form and size of the intended blocks, lumps, or prisms to be formed, and of suiiicient depth to remove the necessary quantity of fine coal. To form the required blocks, lumps, or prisms and subject the mass to sufiicient pressure to cause the particles to adhere and form a solid mass, which may be affected by a piston of'a size corresponding to that of the mold to be operated upon by any suitable mechanical means, and when the fine coal shall have been thus pressed into a solid body it will be discharged from the mold by any convenient mechanical means. The fine coal, being thus formed into solid cubes or other suitable forms, will be in a convenient state for packing, for transportation, or for burning. However, briquettes produced as suggested by Easby, were found to be unsatisfactory; they lack stability and crumble on handling and heating. Only certain solid fuels (namely those of the German brown coal type) were found to be amenable to briquetting without further ado. In order to produce satisfactory briquettes from bituminous coal fines, two methods were developed involving either the addition of binding materials to the coals to be briquetted, (e. g., U. S. Patent 1,507,679 Nagel, 1924), or the application of heat to such an extent as to produce plastic binding material in the coal during the process of briquetting, (e. g., U. S. Patent 2,021,020 Piersol, 1935). The best briquettes have been obtained by the addition of asphaltic binders to dry powdered coal; the fire hazard in this process is obvious and has often been. the cause for abandoning a briquetting project.

In order to overcome diiiiculties inherent to the prior art,- I have found it useful to avoid completely the admixture of binders, or the application of heat, and to provide a size of the shaped fine coal not exceeding five cubic centimeters per body down to lentil and pea size, i. e., a size much smaller than even' the smallest briquettes on the market. Manufacture is easily accomplished by the utilization of two unexpected observations:

(1) Coal dust mixed with approximately 10% water is easily compressed into stable small bodies having the shape of lentils, peas, cylinders, spheres, cones, saddles, or any other shape and form, if an upper limit of volume of approximately 5 cc. is provided;

(2) The compressed, smooth and shiny bodies lose their moisture content readily to the air without showing any tendency of reabsorbing water. This property is remarkable: air dry pellets could be kept under water for several months crumbling or decomposing. The great advantage of this property for storage, transportation, and use is obvious, especially if it is considered that coal dusts and fines readily absorb and I tenaciously retain moisture. It is within the scope of this invention to us a variety of shapes and forms, and to mix different sizes of one shape, or different shapes, for most economic utilization of storage space. A

further beneficiation of this virtually dustless fuel is possible: by covering the compressed bodies with a very fine film of an oily or waxy substance any tendency of dustiness may be completely suppressed, and-the stability of the product increased.

Example-1000 grams of coal dust (47.5% '+100,52.5%-100 mesh) with a moisture conwithout showing any tendency of UNITED STATES PATENTS compressing coal dusts and fines having :3. mois- 22112223385513 2121 2152223112223: 3:522? 3 5 gg WALTER FUCHS- 1,1001710 Brune iz li rfjfffhnes, 1914 REFERENCES CITED 6 FOREIGN PATENTS The following refereizces are of record in the Numb Country 1 Date 7 29,009 British 1913 file of this patent: