US2382809A - Coking expanding coal - Google Patents

Description

Patented Aug; 14, 1945 COKING EXPANDING COAL Carl Otto, Manhasset, N. Y., assignor 'to Fuel Refining Corporation, New York, N. Y., a corporation of Delaware No Drawing. Application March-3, 1942,

Serial No. 433,119

1 Claim:

The general object of the present invention is to provide a simple and efiective method of preparing a low volatile, expanding, or swellin coal for conversion into coke suitable for metallurgical use by high temperature carbonation, without subjecting the coking chambers in which the coke is formed to objectionable stresses as a result of the expansion or swelling of the coal coked therein. In high temperature carbonation, the coking chamber wall temperatures are customarily of the order of 2500 to 2700 F.

The invention is adapted for use in coking coals containing not more than 22% of volatile matter and can be used in coking inferior coals such as slack coal and coal screenings or fines, as well as in coking better grades of coal.

In accordance with the present invention finely divided coal with a moisture content high enough to make the coal crumbly is stirred or agitated to enlarge the spaces between the coal particles so that when a charge of such coal'is placed in the coking chamber in which it is to be coked the weight per cubic foot of the coal in the charge is substantially less than it would be if the charge consisted of the same coal, similarly divided, but in a dry condition.

In the practical use of the present invention, the coal is subdivided to such fineness that all of it will pass through a No. '7'(micron 2830) screen, and 80% of it will pass through a No. 10 (2000 micron) screen and at least 40% of it will pass through a No. 40 (420 micron) screen. The amount of water in the wet coal mass needed to give the latter its characteristic crumbly condition, increases with the fineness of the coal, and its weight may vary between 8% to 20% of the weight of the coal.

To facilitate the thorough wetting of the coal, some suitable wetting material or agent may be used or, for example, soap may be added to the water, or use may be made of some commercial wetting agent now on the market, such as "Wetanol. The coal may be given the desired water content during-or preparatory to the final subdivision of the coal. When the final subdivision of the coal is effected in a hammer mill, the latter subjects the coal to the stirring action or agitation necessary to make the aggregate air and water filled spaces between the coal particles twenty per cent or so greater than the aggregate air filled void spaces in an equal volume of dry coal of the same composition and fineness. In ordinary practice the weight of the coal in the wet coal mass charge in the oven chamber should be about forty-two pounds per cubic foot.

Low volatile, expanding coalprepared for coking in the manner described may be coked in ovens of standard type used in the manufacture or metallurgical coke and operated within the temperature and coking time ranges customarily coking in the manner above described and the strength ofthe coke produced, may advantageously be improved in some cases by adding to the coal from two to five per cent by weight of finely'subdivided coke or coke breeze, and further improvement in the coke produced may be obtained in some cases by adding to the above described coal and coke mixture, an amount of. finely, subdivided pitch equal in weight to about five or six per cent of the weight of the coke in the mixture. When coke and pitch are thus added to the coal, the coke may be initially mixed with the pitch and the mixture may then be heated to more or less completely melt the pitch and thereby agglomerate the mixture, after which the agglomerated mixture may then be ground to such fineness that all, or practically all of it will pass a No. 40 (420 micron) screen.

While in accordance with the provisions of the statutes, I have illustrated and described the best form of embodiment of my invention now known to me, it will be apparent to those skilled in the art that changes may be made in the form of procedure disclosed without departing from the spirit of my invention, as set forth in the appended claim and that in some cases certain tea, tures of myinvention may be used to advantage without a corresponding use of other features.

Having now described my invention, what I claim as new and desire to secure by Letters Patent is:

The method of preparing and coking a low volatile, expanding coal for high temperature carbonization in a coking chamber, which consists in finely subdividing the coal to such fineness that about eighty per cent of the coal will pass a No. 10 (1 680 micron) screen and wetting the coal with water to give it a moisture content of from eight to twenty per cent by weight of the coal to thereby form a crumbly mass and agitating said mass and thereby increasing the aggregate volume of the space between the coal particles so that the weight of the coal in a cubic foot of the wetted, coal mass is less than fortyfive pounds, and in coking the coal so prepared in a deep, narrow and horizontally elongated coking chamber of standard type used in the manufacture of metallurgical coke.

. CARL b'r'ro.