US1445735A - Method of producing coke - Google Patents

Description

JI'ES Gr. WEST, 01E PITTSBURGH, PENNSYLVANIA.

ian'rnon or ienonucrne cons.

No Drawing;

T 0 all whom it may coneerm:

Be it known that l[, alarms Ur. TVs-sir, residing at Pittsburgh, in the county of Allegheny and State of Pennsylvania, a citizen of the United States, have invented or discovered certain new and. useful Improvements in Methods of Producing Coke, of which improvements the following is a specification.

My invention relates to improvements in the coking of coal, and its object is the production from bituminous coal of high volatile content (a content so high that but for my invention, the material would be inferior for the end in view) metallurgical -coke,-coke, that is to say, serviceable in the blast furnace in the smelting of iron ore. This application is in part a continuation of an application filed by me November 26, 1920, Serial No. 426,510.

There are certain ideals in the quality of coke, particularly as regards physical characteristics, which are realized in the cokes produced from coals of certain 'q'uality, found in certain favored regions, and to these idea-ls the cokes produced from coals of less favored regions approach in different degrees of proximity. The natural supply of the best coals is of course diminishing and their value is increasing.

llt appears that, following methods of coking hitherto in vogue, and speaking of Pennsylvania coals at least, coals whose volatile content approaches but does not exceed 31% afford coke best suited for blast-furnace use; and that cokes produced from coals of higher volatile are relatively soft, do not serve so well in the blast furnace, and, be sides, suffer relatively great waste inhandlin My invention is directed to making available as a source of good metallurgical coke. coals which because of high volatile content are otherwiseunsuitable, or at-least inferior, for that purpose.

l[ find, and herein-lies my invention, that by taking a quantity of high volatile coal and subjecting it to distillation and continuing distillation until'aportion, buta. portion only, of its volatile content has beendriven ofi', while the mass under treatment still retains volatile ingredients in substantial quantity and in consequence still possesses certain physical characteristics; then cooling the mass, crushing it and mixing it with new quantities of terlal, and finally coking the mixture, carryadequate for blastlrnace use, that is .of partial removal Application filed February 16, 1922. Serial No. 537,088.

cokable mamg the operation this time through to the end-I find that b doing-so I obtain coke to say metallurgical coke of high quality.

he raw material may vary in volatile content. As I have said, I contemplate working with coal whose volatile content is so great that by methods hitherto in vogue only weak and inferior coke gan be produced. The. limit here is a fluctuating one; but. dealing with Pennsylvania coals as example. it may be given with reasonable pre- ClSlOIl as81%. The coal with which I have achieved my invention is Pennsylvania coal whole volatile content amounts to 32-34%. The initial operation is essentially one of distillation; it should be performed in a retort oven, in order that the desired initial removal of volatile matter may be achieved withoutany ment. The degree to which this initial step of the volatile content, may advance admits of some latitude, and

is not susceptible to precise definition in an the point where cooling interrupts the progress of distillation. lit-is impossible-to see and discern conditions as they then are, but cooling will leave a mass, not brittle and friable. like soft coke, but tough andcellular. Particles crushedbetween thumb and finger will give a smudge. The com dition and appearance generally are such as to indicate that at the moment of suspension of distillation the mass was still melted and gummy and foaming in character.

The cooling of the charge of' partially may be accomplished in usual and familiar manner. So with the mixing of the intermediate ,product with new quantities of coked material, the drawing and'crushing,

"eration.

cokable material. usual methods may be pursued. rinding may precede or may follow mixing. or partial grinding before mixing may be followed by further grinding after. Ordinarily the new quantities of cokable material will be of'raw coal. and ordinarily they will be of the same coal as that with which beginning was made.. But of course the blending of different coal is not forbidden.

The result of mixing will bea mass which as a whole possesses a volatile ingredieno approximately that of the ideal coal mentioned above-28% or thereabouts. In my work upon Pennsylvania coal it appeared that the additions of raw coal to the intermediate product exceeded the intermediate product in quantity. and this condition will I believe obtain in all practical operations.

The ultimate coking operation may be performed in a coke oven of any preferred typeretort or open-burning. I prefer. however. to complete the operation in a retort oven. This ultimate step will be the typi -al coking operation. practiced as upon the usual furnace charge. 1

If the initial step of distillation be carried beyond a certain point which. in Pennsylvania coal atleast. lies somewhere from Gjto 10% volatile. the substance will begin to assume the physical characteristics of coke. that is to. say when cold it will have gained greatly in hardness. and will begin to possess that metallic ring when struck .with which anyone acquainted with coke is familiar.

'hen dealing with coal of given grade. simple and obvious tests will indicate. to what extentexactlv the initial distillation may with best results carried. and in what proportions precisely the ultimate coke oven charge should be compounded. I have indicated general conditions. compliance with which will achieve success. I add. by way of illustration. specific figures of a partlcular op- The raw coal used in this illustrative operation is one having a volatile content of 34%. By the initial step of distillation the volatilecontent is reduced to 17%. The product of the initial distillation is mixed with more of the same raw coal in the ratio of 1 3. The legular coking operation follows. This regular coking operation I preferably perform in a retort oven. but as I have said it may be performed in an oven of any preferred type.

I am aware that proposals have heretofore been made to coke coals by two-step processes These proposals have for the most part at least concerned the production of briquettes for use as domestic fuel. and have involved mechanical pressure upon the mass under treatment as an essential condition of operation. They have come to nothing. Certainlythey have had no value nor,

effect at all in the art of producing metallurgical coke.--an art which is highly spe cialized. and whose requirements are exact ing. These earlier proposals to which I here allude have taught the art of producing metallurgical coke nothing. and could teach nothing; for, as I have learned by experimentation and study. it is necessary to success. so far as metallurgical coke is concerned. that in the ultimate oven charge both components of the mixture shall have volatile contents of substantial proportion; in the ultimate coking operation every ingredient particle of the mixture must under heat be changed: its fusible content must melt and integrate with the fused content of the whole. Thus and thus only does the way open to reach a pr-actical result. so far at least as the production of metallurgical coke is concerned. The earlier proposals to which I allude have not recognized the importance and necessity of this detail of procedure. Xor have these earlier proposals involved any certain teaching as to the proportions in which the initially treated material shall be. mixed with fresh quantities of raw material.

I have found the first condition essential to success to be that the initial step shall be a partial distillation: that the intermediate product shall still retain a substantial contentof volatile matter: that at distillation temperature it shall still be fusible and shall become a gummy foaming mass. Incidentally I find. and I believe it to be an essential condition to success that in mixing the intermediate material with fresh quantities of raw coal. the new material shall not be less in quantity than the already treated intermediate product.

I claim as my invention:

1. The method herein described of pro-.

ducing from high volatile coal metallurgical coke which consists in subjecting a. body of such coal to distillation. and while the material under treatment is still a. fused and gummy mass. cooling it. then crushing andmixing the material with another body of cokable material. and coking the mixture to the end.

2. The method herein described of producing am high volatile coal metallurgical coke which consists in subjecting a bod of such coal to distillation. and while the material under treatment is still a fused and gummy mass. cooling it. then crushing the so treated material and mixing it with another body of the same material in raw state. and coking the mixture to the end.

3. The method herein described of producing from high volatile coal metallurgical coke which consists in subjecting a body of such coal to distillation. and while the material under treatment is still a fused and gummy mass cooling it. then crushing the so treated material and mixing it with an less than 6%, then cooling the mass, and at least equal mass of unmodified coal, and mixing with it an at least equal quantity of i0 coking the mixture. raw coal, and finally coking the mixture.

4:. The method herein described of pro- In testimony whereof have hereunto set ducing from'high volatile coal metallurgical my hand. coke which consists in subjecting a body of JAMES G. WEST. such coal to distillation and by distillation Witness: reducing its volatile content to a value not R. H. LAUTZ.