US2321238A - Smokeless briquette - Google Patents

Description

INDEX PARTICLE DIAMETER (IN) June 8, 1943.

R. J. PIERSOL SMOKE LESS BRIQUET Filed Aug. 50, 1941 I0 20 3'0 4'0 5'0 0'0 T0 FUSAIN (PER CENT) FIG. 1

SMOKE- 0 IO "(0 FUSAIN (PER cENTJ FIGi.

INDEX SMOKE FUSAIN (DER CENT) FIG. 2.

IN ENT0E the coal beds started to form.

product being 'vention Patented June 8, 1943 SMOKELESS BRIQUETTE Robert James Piersol, Champaign, Ill.

Application 3 Claims.

An object of my invention is to provide a smokeless briquette from bituminous coal without carbonization.

, More particularly it is the tion to provide a smokeless object of the invenbriquette from bitu- August 30,1941, Serial No. 408,957

, panying drawing,

minous coal fines rich in fusain, which is a banded V ingredient in bituminous coal. Fusain is commonlY coal.

from wood charcoal produced by prehistoric forest fires at the geologic period during which Fusain is a smutty black powder which largely forms the parting planes in banded bituminous coals. Fusain is very high in fixed carbon and very low in volatile matter.

A further object of the invention is to provide a smokeless briquette from products such as deduster dust and sludge, which are discarded in the cleaning of bituminous coal. Such products are rich in fusain due to the pulverant and friable nature of fusain, which tends to concentrate in the very fine sizes of bituminous coal.

A further object of my invention is the conservation of natural resources by the processing of a smokeless briquette from a waste product produced in the cleaning of coal, such waste product being discarded because in its raw state and the quantity of such waste of very large tonnages, with annual production in excess of one million tons for the State of Illinois.

A further object of the invention is to provide a smokeless fuel by briquetting bituminou coal fines, rich in fusain, without the use of a binder by the process disclosed in my Letters Patent No. 2,021,020, using a briquetting press disclosed in my Letters Patent No. 2,119,243, thus eliminating the smoke produced from the usual asphalt binder.

A further object of my invention is to a smokeless fuel by briquetting coal fines, in fusain, with the use of a smokeless binder, such as starch.

More particularly it is my object to provide a smokeless briquette from bituminous coal fines, rich in fusain, by the use of a briquetting process which does not add a smoke producing ingredient to the briquette.

provide in view my inconsists of botha smokeless briquette and the process for making a smokeless briquette from bituminous coal fines, rich in fusain, whereby the objects contemplated are obtained, as hereinafter more fully set forth, pointed out in my from a typical dry it has no market rich I concentration of claims; and the effect of various percentages of fusain on the smoke producing characteristicsof the resultant briquette is illustrated inthe accomin which: y 9 Figure 1 is a graph which shows the normal fusain in the very fine sizes of coal. This particular graph is for deduster dust coal cleaning plant located in southern Illinois. The deduster dust is a waste product which'consists of the very fine sizes of coal, which are air separated from stoker coal.

Figure 2 is a graph which shows the influence of the percentages of fusain in the various screen sizes of deduster dust on the smoke index, which is a quantitative measure of the smoke producing.

potentiality of the resultant briquette made without an added binder. r Figure 3 is a graph which likewise shows the influence of the percentage of fusain on' the smoke index of the resultant briquettes, thehand picked pure fusain being blended in various percentages with fusain free high volatile coal.

Analysis of the above illustrated experimental data shows that the percentage of fusain increases from about 4 per cent, which is approximately the average percentage of fusain in the corresponding lump coal, up to 37.5 per cent for the very finest sizes of deduster dust and that the smoke index of the resultant briquette diminishes linearly with the increased percentage of fusain, vanishing at 40 per cent fusain.

In general it is found that the smoke index of natural coals, and briquettes made from natural coals, decreases linearly with decrease of percentage of volatile matter and therefore the percentage of volatile matter has become the criterion for acceptance of smokeless coal under certain smoke abatement ordinances, one value being 23 per cent or less, volatile matter; the re- I sultant smoke from coal of said volatile matter corresponding to a smoke index of 2300. Therefore the term smokeless is used herein to designate such a coal fuel.

One skilled in products from coal would therefore expect that the addition of fusain to high volatile coal would decrease the smoke index of the resultant briquette only to the extent that the percentage of volatile matter would be lowered on account of the very low volatile content of fusain which is usually 5 per cent or less. However, experiment proves, as illustrated in Figure 3, that a briquette containing 15 per cent fusain possesses a smoke index of 2300 units, although chemical analysis the art of processing smokeless that from coal rich in fusain consists shows that this briquette contains over 30 per cent volatile matter.

After having established experimentally that the smoke produced from a briquette made from coa fin8S rich in fusain is several fold less than which would be predicted from the resultant decrease of percentage of volatile matter due to the fusain, I have found that this unexpected decrease in smoke is due to acatalytic reaction of the fusain which reacts in combustion in a manner similar to activated charcoal, thereby accelfraction of the volatile matter which is the normal smoke producing ingredient of bituminous;

coal.

The process for making smokeless briquettes g of concentration of fusain in the very fine sizes of coal by means of dry dedusting or wet washing, and ofthe' removal of oversize cent or more fusain, and of ,briquetting without added binder or If the product, rich in fusain, is briquittedwithout binder, the preferred method i to preheat the product to a temperature somewhat less than its initial softeningpoint and to apply impact pressure of relatively high magnitude in order to flow the product intoa briquette.

that one preferred set of consists of a temperature of about 350 degrees centigrade, a pressure of about 30,000 per square inch applied for a period of about one tenth of a a second in the specially designed press described in my Letters Patent No.

not, rich in fusain, is briquetted with a smokeless binder, usual briquetting processes and usual briquetting equipment may be used.

described, is now being My invention, herein fines, usually over mesh in size, in order that the material contain 15 per 2,119,243. If the prod from 15 to 40 per cent commercialized on a large scale and the resultant smokeless briquette has been accepted ofllcially be reasonably included within the scope of my invntion.

I claim as my invention:

'1. A briquette which consists of from to per cent high volatile bituminous coal and of fusain, and with a range of smoke content between 2300 and zero smoke I index units.

2. A briquette composed of high volatile bituminous coal and admixed fusain with an optimum proportion of about 20 per cent fusain, and with a smoke content of about 1800 smoke index units.

3. A process for with smoke-index less than 2300. from high volatile smoke producing bituminous coal, consisting manufacture of briquettes,

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