US1368987A - Process of activating carbon - Google Patents

Description

J. C. WOODRUFF.

PROCESS OF ACTIVATING CARBON. APPLICATION FILED MAY 8, 1919.

1,368,987.- Patented Feb. 15, 1921.

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UNHTEEB STATES PATENT @FFEQE JOHN c. woonnurr, or NEW Y RK, N. Y.

PROCESS ACTIVATING CARBON.

To all whom it concern: Be it known that I, JOHN C. WOODRUFF, a citizen of the United States, and residing at New York city, N. Y., have invented certain new and useful Improvements in Processes of Activating Carbon, of whichthe following is a specification. This invention relates to the manufacture of absorbent carbon and has special reference to a process of rendering carbon, such as charcoal, highly active as an absorbent. Heretofore, charcoal has been activated by means of steam in vertical tube furnaces called Dorsite treaters. This type of furnace consists of a nichrome tube symmetrically set in a vertical position and surrounded by a cylindrical combustion chamber heated .to about 1100 C. by gas burners. On the inside of the above mentioned nichrome tube, there is concentrically located a nichrome steam pipe having part of its 'length perforated, and covered with n1- chrome wire cloth of rather fine mesh which is smaller than the particles of the material treated. The gaseous products. of the reaction are drawn ofi through exhaustports by means of a vacuum pump. Granular charcoal is introduced through a hopper valve feeding device at the top. The space surrounding the steam jet is. kept full of carbon and as a portion is discharged from the bottom of the tube, thus lowering the level of the material in the tube, the level is replenished through the feed valve at the top of the furnace. Thus, a continuous gravity passage of the charcoal through the tube is maintained, unless interfered with by gas pockets, and the charcoal is activated by the superheated steam admitted through the steam 'et. 4

The big est quality of absorbent charcoal is obtained only by running the material at a very slow rate or by re-running it several times through this type of furnace. This process re uires a large amount of time and fuel. Di culty is experienced in feeding due to the formation of gas pockets which hold the charcoal from sliding after the material is discharged from the bottom. The exhaust lines constantly give trouble by becoming plugged with charcoal.

Specification of Letters Patent. Patenjggdl Feb, 15, 1921, Application filed May 8, 1919. Serial No. 295,62l;

come the disadvantages hereinbefore described in the prior processes.

Anotherfobject of this invention is to avoid the use of expensive nichrome tubes, which usually burn out and also have the troublesome steam jets. Reference is to be had to the accompanymg drawmgs in which Figure 1 isa view in elevation of the apparatus used in my process, part of the device, however, being shown 1n section.

2 is a section along the line 22 of 1g. This apparatus is similar to a cement ln'ln in construction and operation and consists of a long slightly inclined cylinder (1), preferably of steel, and lined with a refrac tory substance (2), such as fire brick, and is mounted on rollers (3) so that it may be rotated. The high end of the cylinder has a charglng device (4) and an operating outlet (5) for the flue gases. At the lower end is a discharging devlce, shown in a diagrammatic way, by the pipe (6). A fire brick box (7) at this. end provides for the burning of coal, coke, powdered coal or tar-oil and is so built that the hot flue gases pass throughthe revolving tube. Steam, air, CO or other oxidizing agents are also admitted at this end.

Carbon is charged into the cylinder through the charging device (4) and as it passes through the cylinder it comes into contact with the hot flue gases and steam at a high temperature, and the material becomes readily activated. It has been found that a temperatureof 700 to 1100 C. produces satisfactory results.

With this internally fired rotary furnace a high percenta e of yield ma be obtainedand the materia may be pro uced in very large quantities. lThe peculiar eficiency of the process depends primarily upon the combined features of continuous agitation of the carbon while undergoing oxidation and the delivery 'of the oxidizing and heating gases directly to 'the reaction chamber wherein they are mingled freely. with the carbon while the required temperature is readily maintained. By employing the heating gases directly, the heat is conserved and the process rendered rapid and economical. The uniform and highly active product ma be used for a variety of purposes to whlch it is adapted. i

The furnace described is more economical than the Dorsite apparatus from the standpoint of both installation and operation, and there are no expensive nichrome tubes to be burned out nor troublesome jets with which to contend.

The present invention is not limited to the specific ,details set forth in the foregoing examples which should be construed as illustrative and not by way of limitation, and in view of the numerous modifications which may be efiected therein without departing from the spirit and scope of this invention, it is desired that only such limitations be imposed as are indicated in the appended claims.

I claim as my invention:

1. A process of treating carbon by oxidation, which comprises, continuously agitating the carbon while conveying it through a reaction zone and subjectin the carbon while in said zone to the com ined action of steam and hot combustion gases, the latter gases furnishing the necessary heat to maintain the temperature at a point insuring rapid activation of the carbon. 7

2. A process of treating carbon by oxidation, which comprises, continuously agitating the carbon while conveying it through a reaction zone and subjecting the carbon while in said zone to the combined action of steam and hot combustion gases, the latter gases furnishing the necessary heat to maintain atemperature of between 700 C. and 1100 C.

JOHN C. WOODRUFF.

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