US769241A - Process of coking coal. - Google Patents

Description

No, 269,241. PATENTED SEPT. 6 1904. c. F. SPAULDING.

PROCESS OF GQKING GOAL.

APPLICATION FILED AUG. 31 1903- N0 MODEL.

A nrrg Patented September 6, 1904.

CHARLES F. SPAULDING, OF CHICAGO, ILLINOIS.

PROCESS OF COKING COAL.

SPECIFICATION forming part of Letters Patent No. 769,241, dated September 6, 1904.

Application filed August 3, 1903. Serial No- 167,988. (Nospecimeua) T0 aZZ whom, itmay concern:

Be it known that I, CHARLES F. SPAULDING, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented a certain new and useful Improvement in Processes of Coking Coal, (Case No. 1,) of which the following is a full, clear, concise, and exact description,'reference being had to the accompanying drawings,

forming a part of this specification.

My invention relates to a process for coklng coal; and its ob ect is to provide means whereby the volatile elements of the coal may be driven off thoroughly, quickly, and more economically than has heretofore been possible.

In the ordinary process of coking coal in which a beehive oven is used the coal is placed in the oven to a depth of about two feet, and the coal is fired either from the heat remaining in the oven from the preceding charge or when the oven is started for the first time or after it has become cold by a wood-fire which is kindled in the oven. the process of coking coal in the beehive oven an opening is left in the front of the oven until i the process has progressed to a certain point, when the opening has to be closed up to eX- clude the oxygen and prevent combustion of the coal itself. This process is one which takes a considerable time, the time for thoroughly coking the charge varying from thirtysiX hours to seventy-two hours. In the practice of my process, as hereinafter described, I am able to coke the same coal in about onethird the time. I am further able to coke coal which has heretofore by the old. process been called non-coking coal. By my process also, in which a very high temperature is used in the oven, I am able to precipitate a greater portion of the carbon element of the volatile portions of the coal which are driven off in the process of coking, and thus produce a larger yield of coke. In the old process of coking, as well as in the process of my invention, the heating of the coal drives off certain gases. Of these gases certain hydrocarbons contain carbon which under the influence of heat becomes separated and precipitated as a part of the fixed carbon of the coke. The

In the early part of gas.

higher the heat the greater the proportion of this carbon, constituting an element of the generated gases, which becomes precipitated and saved as a part of the coke which results .from the process. I do not claim the process of precipitating this carbon. The old process accomplished this result; but the process of my present invention has the advantage of securing it to a higher degree and more economically than the old process of coking in beehive ovens as it has long been practiced.

Broadly considered, my invention consists in increasing the temperature in the cokingoven by an admixtu'reof good combustionsupporting gas with atmospheric airprior to the admission of the air into the chamber or simultaneously with the admission of the air into the coking-chamber.

My invention will be more clearly understood by the following description, which is made with reference to the accompanying drawings, in which I have represented the means which I prefer to employ for carrying out this process.

Figure 1 represents the coking-oven and the auxiliary apparatus for supplying the air and Fig. 2 is a diagram showing comparative time and temperature curves of the old process of coking and the process of my invention.

The beehive oven at, which is intended to represent one or any convenient number of such ovens, of the usual form having the trunnel-hole at b and the discharge-opening c. Blower d, driven by any suitable prime mover, communicates with the upper part of the oven through the pipe 0, which leads into the oven about siX inches above the top of the coal in the oven. I incline the pipe as it enters into the oven at an angle of about ten or twelve degrees from the horizontal, so as to give the draft of air which is forced through the pipe an upward tendency. I have found in practice that if the air is direct'edjin'a parallel course over the surface of the coal a furrow is burned in the coal by means of this air thus wall of the upper part of the oven, and reverberating in the upper part of the oven finally passes out with the unconsumed gases and products of combustion. The efiect of the draft of air thus directedinto the oven is twofold. It increases the combustion, and thus raises the temperature, and it also causes a stronger outflowing current through the trunnel-hole to carry away any incombustible portions of the generated gases.

To still further increase the temperature of the oven during the process of coking, I have provided means for adding to the air a supply of oxygen or other gas which aids combustion and this I will now describe. The retort f is provided with a furnace g, by which the retort and its contents are heated. In the retort I place potassium chlorate, which under the influence of heat gives ofi oxygen. Leading from the retort is the pipe h, leading by two branches it 72 to the receivers is Z. from these receivers, by two pipes which are joined at m, the gas in these receivers may be led to the main pipe 6, whence it is mingled with the blast of air from the blower, and thus carried into the coking-chamber. In each of the branch pipes I provide the valves or 0 p g, by means of which either one or both of the receivers may at will be cut off from either the retort or the pipe leading to the cokingoven. In this way I am able to keep a constant supply of the gas for aiding combustion, such as oxygen, and admit the desired amount to the main pipe at, all times. The valve 0* in the main pipe 0 serves to control the flow of mingled air and gas into the oven or to shut it off altogether, if desired. I have found in practice that for maintaining the process of coking at an eflieient point an average of two hundred cubic feet of air a minute may be used to advantage and mixed with this about five per cent. or ten cubic feet of oxygen a minute. ited to this precise proportion of admixture of the gas for accelerating combustion.

In carrying out my invention I start the coking process in the usual way-that is, I fill the coking-oven to about two feet from the bottom with the coal which is to be coked and fire the coal by the heat which is retained in the walls of the oven if a charge has recently been withdrawn. If the oven is cold, it has to be heated by a fire before the charge of coal to be coked is put into the oven. After the coal is fired in this way I start the blower and admit the current of air mixed with the gas intended to accelerate the process. This brings the temperature in the oven to a very high degree of heatsay, probably, upward of two thousand degrees. This high temperature is continued for a time suflicient to drive off all the volatile constituents of the coal. After the temperature has thus been raised to this very high degree the blast may be reduced or entirely out off, and the process of coking still goes Finally- I do not wish, however, to be limon until the charge is hard enough, when it may be withdrawn. With this process of my invention the heat is not only more intense in the oven during the process of coking, but it starts at a higher ilGlTll')Gllti3l1l0 and is kept at all times at a higher temperature than in the old process of coking-that is to say, using for illustration figures which are to be considered only as illustrative and not absolute, with the old process of coking in beehive ovens the temperature at which the process begins may be from four to live hundred degrees and gradually and slowly rise to a maximum temperature of possibly eighteen hundred degrees, whence it falls again to the comparatively low temperature of starting. My process, on the other hand, uses initially a temperature of possibly eight hundred degrees, which temperature quickly rises to twenty-five hundred degrees, from which point it falls off again to the temperature. of starting. As a graphic illustration of the comparison of the temperature used in the two processes reference may be had to the curves shown in Fig. 2, showing the relative temperatures approximately and relative times approximately of the processes of coking, comparing the old process with the process of my invention set forth herein. These curves are drawn with the ordinate of temperature and abscissa of time, and the curve A B represents the curve of the temperature for different times of the old process, while the curve C D represents the curve of temperature for different times of my process. Bearing in mind that this re in'esentation is not intended to show absolute values, but only approximate, it will be seen that my process greatly expedites the process of coking. it also accomplishes the other results to which I have hereinbefore referred--namel y, the coking of hitherto considered non-eokahle coal and the increase of the product.

Another incidental advantage of my process is that it permits the coking of a larger mass of coal at a single operation than the old process allowed. In the old beehive oven the maximum charge is live tons of coal, whereas with my process I am able to coke seven and one-half tons of coal at a time, or fifty per cent. more at a single operation.

While I have set forth the apparatus with which I prefer to practice my invention and have mentioned particular proportions and temperatures, it will be understood that these may be modified and varied without departing from the spirit of my invention. I do not, therefore, wish to be limited to the specific details of construction in carrying out my process, nor to the precise proportions of atmospheric air and gas, nor to the precise temperatures set forth.

What I claim as new, and desire to secure by Letters Patent, is--- 1. The process of coking coal, which condirection inclined upward from the horizon- I sists'in confining the coal in an oven, firing tal, substantially as described.

the coal, and then forcing into the oven above the coal, a blast of combined air and oxygen,

substantially as described.

2. The process of coking coal, Which consists in confining the coal in an oven, firing the coal, and then directing into the oven above the coal a blast of air and oxygen in a In Witness whereof I hereunto subscribe my name this 15th day of February, A. D. 1901.

CHARLES F. SPAULDING.

Witnesses:

LYNN A. WILLIAMS, HARVEY L. HANSON.

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