US1283310A - Method of making low-density coked products. - Google Patents

Description

HUGH BODMAN, OF EDGEWOOD, PENNSYLVANIA, ASSIGNOR '10 RODMAN CHEMICAL COMPANY, A CORPORATION OF PENNSYLVANIA.

Be it known that I, HUGH RODMAN, a citizen of the United States, and a resident of I Edgewood, in the county of Allegheny and State of Pennsylvania, have made a new and useful Invention in Methods of Making Low- Density Coked Products, of which the following is a specification.

This invention relates to the production of low density coked products and discloses a new and improved method of making such products.

Efforts have been made to make low density products by heating a coking material or a mixture containing coking material in such a way as to produce masses of light, porous coked material, these masses being generally crushed and screened to ob tain the size of product desired. As this process is articularly applicable to the production of carburizing material, I will de scribe it in that connection, though the art is also applicable to the production of filter inimaterial, filling for reaction towers, etc.

imiting the description further to the use of a single coking material, I will describe a process which I have used commercially for the production of light, coked, carburizing material and then describe the new and improved process forming the basis of this patent application,

I have hitherto made light, coked carburizing material by mixing a mass of finely powdered coking coal with powdered energizers, such as lime and soda ash, and then feeding this mixture into a heated revolving kiln so that the mixture was coked while tumbling. In this way I have produced excellent carburizing material, but in general have found great difliculty in regulating the operation so as to avoid the production of dust and oversized material. The object aimed at was the production of light coked masses about one quarter inch in diameter, but there would always be considerable material in lump larger than desired and also considerable small material and dust. The

oversize lump could of course be crushed to proper size, but in doing so more dust was produced, and the dust was generally waste or required further, expensive treatment.

' My present inventionlis a process of-. making such light coked products practically Specification of Letters Patent.

Patented Oct. 29, 1918.

Application filed February 7, 1917. Serial No. 147,099.

without waste and in a way that allows of great flexibility both in manufacturing and 1n the character of product produced. That is, it gives a means of maklng the material without the production of dust and also makes it possible and easy to produce material of any density desired. It also produces an improved light coked product in that the finished roduct has a comparatively smooth sur ace, differing from the edged and angular product obtained by crushing, and therefore less liable to produce dust in handling. It also makes possible the production of a very uniformly sized product, as the material, in this new process, is sized before being coked, and the uncoked oversize and undersize material can be easily manipulated to produce proper sizeduncoked material; in this Way avoiding all Waste.

The new process consists in forming the raw material into pellets 0' fragments of proper size and so made that hey will, when heated quickly, expand in size, or at least not contract, and coke to a firm material of the size desired without breaking up or adhering to neighboring fragments and without producing any considerable dust.

Before describing the process further, I will explain that I have hitherto made carburizing material by fashioning coking material, or a mixture containing coking material, into pellets or fragments and have then coked them, either before or during use as a carburizing agent, to produce small unit masses of coked material. This old process differs from the present one in that the pellets or fragments produced were of such construction and coked in such a way that the resultant coked product generally occupied a much smaller volume after coking than before. In other words, each small fragment or pellet would shrink in volume durin the coking process till it occupied rough? 60% to of its original raw volume; and the final product was therefore, generally dense and heavy.

I now find that by coking the pellets or fragments as originally made, but much more rapidly than was customary, and also by changing the formula of the mixture and then coking rapidly, I can cause each individual pellet or fragment to expand in size B during the coking process, instead of shrinking as heretofore, and at the same time cause it to substantially maintain its original contour. In this way I roduce excellent carburizing material of ow density and without waste.

As a concrete example I will state that I have heretofore made pellets orfragments by fashioning a mixture of one hundred parts finely powdered coking coal, ten parts of soda ash and fifteen parts of lime, usin a molasses solution as binding agent, an generally tumbling the material to produce small pellets or pills about one-fourth inch in diameter. These were sometimes dried by entle heat and then used direct as a car- %urizing agent, or they were sometimes fed into the cold end of a rotating kiln and gradually dried and coked and discharged at the hot end. In either case there was a loss in wei ht of about 35% (due to the vaporizing o the water, loss of gas by the coal and reduction of the lime and soda ash) and also a loss in volume of about 35%. The net result was the roduction of raw pills with a density of a out 7 O (figuring water as 100 dense), when measure in coking, lost 35% in volume and 35% 1n weight, leaving finally a coked product having 65% the original weight and still having a density of 7 (The denslty is that of a pile of pellets rather than of a single pellet; that is, a pint of the pellets weighed 70% of the weight of a pint of water). 85 In carr ing out the new process I first dry the pills (if that be necessary) and then heat them very rapidly, generally agitating them at the same time'to destroy any light adhesions. In this way I am able to overcome the excessive shrinkage of the old method, and instead of the pellets losing volume they either hold their original volume or else increase in volume, so that by this new process I can easily make a product with a density of 30 and can vary the density to produce lighter or heavier pellets as desired. The new process of coking very rapidly can be applied to the pellets as formerly compounded, but I prefer to make the pellets for this new process with a weaker bond than before. tion are used there is a setting or hardening effect due to the reaction of these two materials, so that in coking the expanding force of the. ent in gases has to overcome this strong ond. For this reason I prefer to use powdered marble dust instead of lime" with molasses solution and to use a weaker solution of molasses. As an improvement beyond this, I may prefer to use a binding agent having considerable value as a coke producer and I find ordinary tar will serve excellently. I may make the pellets by tumbling the mixture of powdered coal, limeel stone and soda ash (as 100 parts of coal, 10

d in bulk, which,

, broader than these limitations. I have also When lime and molasses soluparts of soda ash and 15 parts of limestone) with liquid tar so as to fashion small pellets or pills; these are screened to secure the sizes desired andthen fed into arevolving furnace or kiln maintained at about 1500 F. The volatile matter from the tar and the coal burn above the tumbling mass and maintain, or help to maintain, the proper temperature and the individual pellets are coked quickly, expanding as before described, and finally discharging into a cooling device. The form of the heating devices for coking the pellets rapidly forms no part of this invention, but I. find a satisfactory device to consist of a rotating furnace so arranged that the incoming pellets fall directly into a considerable mass of tumbling pellets already coked and hot. I can accomplish the same purpose of coking rapidly by feeding the pellets into an ordinary rotary kiln, taking care to see that they quickly reach a coking zone; that is, the ordinary cold, feed end of the kiln is maintained at or near acoking temperature.

I have described one method of making thepellets or fragments, one mixture, one device for coking, etc., and also one objectthe production of light carburizing material, but I conceive of my invention as spoken of the pellets increasing in volume or at least not shrinking. It will be apparent that they might be compounded or manipulated so as to shrink slightly and still mark an advance over the excessive. shrinkage of the old processes.

I have also spoken of tar and its coking properties, but it will be apparent to those skilled in such matters, that other coking materials, aS heavy oil or heav molasses may be used. Also the total co ing material in .the raw pellet or fragment may be the binder, as the tar, the rest of the carbonaceous material in the pellet being non-coking, as charcoal dust; r

What I claim is:

'1. The process of making. low density products which consists in fashioning coking material ora mixture containing coking material into pellets or fragments and abruptly subjecting the fragments to a coking temperature.

2, The process of making low density carburizing materiahwhich consists in manipulating fine material with a coking binder to produce ellets or fragments and then cokmg rapi y by initially subjecting the pellets orfragments to a coking temperaure. Q

3. 'The process of making low density products, which' consists in manipulating fine material with a tarry binder to produce pdelllets or fragments and then coking rap- 4. The process of making low density "coking coal, or a mixture 1,283,310 I lit products, which consists in fashioning fine, containing fine cokingcoal, into pellets or fragments and then coking rapidly, by initially subjecting the pellets or fragments to a coking temperature.

5. The process of making low density products, which consists in fashioning a coking material or a mixture containing coking material into pellets or fragments, the bonding agent of which will not strongly resist disrupting by heat and" then coking rapidly.

6. The process of making carburizing material of low density, which consists in fashioning a coking material or a mixture containing coking material into pellets or fragments and-then expanding them by a substantially abrupt application of a coking eat.

7. The process of making low density products which consists in fashioning coking material or a mixture containing coking material into pellets or fragments, and rapidly coking the same by initially subjecting them to a tumbling or agitated mass of hot previously coked pellets or fragments maintained at a coking temperature.

In testimony whereof I havehereunto subscrlbed my name this 2nd day of February, 1917.

HUGH RODMAN,