US2556154A - Method of making coke briquettes - Google Patents

Description

June 5, 19.51 F. c. KERN 2, 6

METHOD OF MAKING COKE BRIQUETTES Filed June 16, 1947 RAW COAL RAW COAL c usHE PULVERIZER BIN BIN L .SOLVENT RESINIC AG'TATOR CASPHALTIC) SUBSTANCE WET-PAN GRINDER DISINTEGRATOR BRIQUETTING I DRY, I ow TEMPERATURE coKE GASIFIER DISTILLATION B ENZOL c A s PRIMARY TA R OILS G o K E FRAc T IONAL DISTILLATION I I I I I LIGHT MIDDLE HEAVY REsIwE. ARTIFICIAL OILS oII s OILS ASPHALT 0R PITcI-I INVENTOR Patented June 5, 1951 UNITED STATES PATENT OFFICE 2,556,154 METHOD OF MAKING coKE BRIQUETTES Fernando C. Kern, St. Louis, Mo.

Application June 16, 1947, Serial No. 754,965

2 Claims. 1

This invention relates to improvements in the carbonization of coal so as to produce coke and valuable by-products, and more particularly to such a method whereby there will be a maximum yield of tar toils together with coke, of the very highest quality. 7

The invention is related generally to that described in Patent No. 1,899,089, issued February 28, 1933, to Ludwig Kern and myself. In said patent, the coal is described as bein ground to 150 mesh or finer, and to such powdered coal there is added enough of an alkali in aqueous solution to react with the freed ash-forming constituents of the coal, to form a plastic binder therewith, which through suitable homogenizing, plasticizes the entire mass into a firm moldable body from which the briquettes are formed. These briquettes are thereafter dried, and then subjected to distillation or carbonization to recover the volatiles and to form coke. However, tests have shown that although the process is eificient with some coals, yet with others the results were not entirely satisfactory.

The instant invention, although related to the teachings of said patent, difiers therefrom in important aspects, and the results seem uniformly better. Principally, it differs in that the alkali is replaced by a hydrocarbon compound that is liquid or semi-liquid at normal room tempera tures, and which is chemically a close ally to all types of coal and analogous carboniferous' materials.

One of the important objects of my invention is to provide a process that is extremely flexible in its application, and wherein the solid carboniierous materials may be treated separately or in combinations, depending upon their physical and chemical make-ups, as for example, by combining and treating bituminous, semi-bituminous and sub-bituminous coals alone, or in combination with anthracites or other substantially resinic-free coals.

Other important objects of my invention are to provide a method of treating materials of the kind described, so that various types of solid carbonaceous products may be produced, as for example, semi-coke briquettes readily ignitible at about the same temperatures as bituminous coal but which will burn smokeless and without requiring draft, so that it is an ideal fuel for domestic use; an artificial anthracite having all of the desirable properties thereof, but which is ignitible at from 100 to 200 C. lower temperature than said natural anthracite; ina brick form suitable for blast furnaces, foundries, in-

dustrial furnaces and boilers; or to coal gasification, hydrogenation, and for other products requiring high fixed-carbon content.

A further object of my invention is to pro- 5 vide a process of treating solid carbonaceous fuel, so that a favorable exchange is brought about therein in the quantity, speed, and chemical constitution of the by-product hydrocarbons derived therefrom, and at relatively low temperatures.

An added object of my invention is to produce a conversion of highly volatile bituminous coal, rich in resinic content, into relatively large yields of primary tar oils of low specific gravity, averaging between .95 and 1.06, and of relatively low boiling points, said oils being composed mainly of saturated and unsaturated paraflines, olefine's, naphthenes, high-molecular hydrocarbons, and being especially rich in middle oils that contain the highly-prized homologues of the phenolic series.

Another object of my invention is to produce sufficient porosity in the coal being treated, so that it absorbs the plasticizing medium properly while at normal room temperature.

Anaddition'al object of my invention is to practice the invention by intermixing the coal with a liquid or semi-liquid hydrocarbon compound flowable at room temperature and having a boiling point of approximately 125 to 300, C. and which in contradistinction to water, has a high affinity for coal, so as to agglomerate and agglutinize therewith and act as a solvent for the resinic constituents thereof, and in itself having lubricating, coking and distillable properties to thereby increase the fixed and reactive carbon content of the coke.

A still further object of my invention is to produce a method of the kind described, that will not only recover the volatiles inherent in the coal, but in addition, will recover those that may have been added thereto in the carrying out or this process, and whereby the process may be"- come cyclic and self-contained.

Other added objects of my invention are provide a method setforth, wherein the added constituents are introduced at room temperat'ure, carbonization commenced without drying of the briquettes and carried on at low tempera tures, and wherein the coal is changed into a moldable and shape-retaining briquettable mass prior to carbonization.

To this end, my invention consists in the novel process herein shown and described, and the ingredients used, as will be more clearlypointed out in the claims hereunto appended;

In the drawings, there is illustrated diagrammatically, a flow sheet of the sequence of steps in the practice of the invention.

In carrying out my invention, I may use practically any coal, although I prefer to use a bitu-,

minous coal for many reasons, as will be more clearly understood from the disclosures hereof, and it may be mentioned that low-grade coals are admirably suited to suchuse. For example, I have successfully used a low-grade Illinois coal running about percent ash, 3 percent sulphur, 12 percent moisture, 38 percent volatiles and 3'7 percent fixed carbon, and by treatment by this process have converted the same into a high-grade semi-coke briquette containing about 78 to 83 percent fixed carbon, easily ignitible and burnable without draft and entirely'free of visible smoke; thus enabling the use of such briquettes even in those localities having the most stringent anti-smoke regulations.

Such solid carbonaceous fuel, preferably acoal high in resinic content, as for example the bituminous coals, is crushed or otherwise comminuted to pass through a 30 to 40 standard mesh screen. Fuel, either from the same source, or from another source, may be prepared to a more finely comminuted state, so that it becomes pulverized and will pass through about a 200 mesh screen. If desired, this pulverized coal may be sheet, and from whence they may be withdrawn as needed.

As coal, no matter what its fineness, is not moldable at room temperature except possibly under unusually great pressure, without some s-ortof a binder, it will be seen that I have minimized this difficulty, and my process enables the briquetting at relatively low pressure and room temperature, and wherein the briquettes will retain their shape through carbonization and through the subsequent-handling, including relatively rough handling.

I have found that coarse and pulverized coals in about the proportions stated will agglutinize under certain conditions without an extraneous binder, at relatively low pressure and at normal room temperature, by introducing said coals into a wet pan grinder and agitator wherein heavy steel mullers move, with a slight amount of water, and after said mullers have acted for a short time, say about 15' or minutes thereon, to grind, compress, knead and lubricate the mixture, it becomes changed in its chemical and phy-' sical form to an elastic, rubber-like lumpy mass or slab, and the resinic content of the coals have been forced from their original places and states of deposit into the very pores of the coal and especially into the capillary openings formed between the coarse and the pulverized coal particles,

However, I have found that for best results, it is desirable that an additive be incorporated into the coals that are to be intermixed, and have termed this additive an important ingredient of the hydrocarbon compound, the compound comprising such additive or additives together 4 with the pulverzied coal, as will be more clearly hereinafter set forth.

The carrier or diluent for this hydrocarbon compound is liquid or semi-liquid at normal room temperature, with a boilin point ranging broadly between 125 and 300 0., and has the power of being a solvent for'the volatiles or resinic content of the coal. Such carrier may bederived from various sources and may include those from coal tar or petroleum, including the first fractions or light oils from distillation or carbonization,

and may be generally termed hydrocarbon naphtha.

In the commencement of my operations such liquid may have to be obtained from an extraneous source, but after the process has gotten under way, sufiicient amounts may be taken off and returned into the operations to thereby make it a cyclic process. This solvent acts as a vehicle for the resinic constituents of the coal.

If the liquid or semi-liquid hydrocarbon having the foregoing characteristics does not have enough resinic content for the carrying out of this process to best advantage, it may be necessary to add'such resinic or asphaltic substance, and it is to be noted although this resinic substance may be obtained from an extraneous source, yet it can be taken from the residue end of the fractional distillation in my process and returned into the cycle, so that both such resinic substances and the hydrocarbon naphtha are taken from the process itself and introduced at the stage where mixture with the coal is had, and whereby the process is a cyclic one. This resinic 'or asphaltic substance, sometimes called pitch,

is preferably in powdered form of about the same fineness as the pulverized coal.

This resinic substance and the liquid or semiliquid hydrocarbon described, are preferably intermixed with the pulverized coal, using just enough of the liquid to make intoa paste of the desired consistency, and which takes about 20 gallons of the liquid to about 350 kilos of the 'pulverized coal. r r

' Now, in order to better enable the components of this hydrocarbon compound (the liquid hydrocarbon, resinic asphaltic substance and pulverizedcoal) to react fully with one another, it is introduced into an agitator or the like, wherein it is intimately homogenized, with or without heating.

Next, the pulverized coal so treated is introduced in the form of said hydrocarbon compound, into a wet pan grinder and agitator, Where together with added coarser coal, in about the proportions stated, heavy steel mullers roll, oompress, grind, knead and otherwise most intimately intermix the same to'form the contents into an agglutinized, agglomerated lumpy slab of elastic rubber-like mass. The entire physical and chemical structure of the mass has thereby become so chan.g ed and sp0nge-like,'that a piece will withstand the impact of a 25 to 30 foot drop onto a brick floor without breaking or chipping. Such material may be readily shaped into formretaining briquettes at room temperature, with compartively low pressure, say With up to 5000 pounds per square inch, depending on the moisture content.

It will be found that the absorbed compound envelopes all of the coal particles with a distinct.

individual coating, acting as the vehicle for lubricating, 'agglomerating and otherwise binding into such physical characteristic that the particles permit of compression into the briquettes at low pressure. If, in the mixing of the mass, there is not enough moisture for proper molding and briquetting, as will be apparent from visual inspection, additional fluidity may be obtained by added Water. Although it is well-known that bituminous coal is by nature water-repellent and chemically inert, yet it is made to change its characteristics and become spongy and rubher-like after the aforesaid treatment, and capable of absorbing about close to one-half of its weight in litiuid hydrocarbon, and that a 55 gram briquette for example holds enough moisture to be reduced to approximately 30 grams after carbonization.

When the mixing has terminated and the charge has assumed. the slab-like and rubberylike elastic structure mentioned, and which generally takes only about 15 minutes or so, depending upon the varying conditions that may be encountered, the mass is then preferably disintegrated or fragmentized by suitable means, and then, either in such fragments or after shaping into briquettes under relatively light pressure, it is ready for carbonization and distillation without drying.

This elastic mass, shaped or not, as preferred, is carbonized and distilled at relatively low temperatures, as will be more clearly hereinafter set forth, and the crude tar oils obtained will have a low specific gravity and low boiling points and may be separated or fractionated in the well-known manner.

The liquid hydrocarbon naphthas added to the pulverent mass before carbonization act in the beat of dry carbonization upon the resinic part of the coal, dissolving, extracting and separating the same from the fixed carbon and ash constituents of the coal. This action takes place at low temperatures, and this results in increasing the mechanical strength of the resultant coke, and besides, accelerates extraction. Carbonizing takes place in from 2 to 6 hours with my method, as compared with from 20 to 25 hours in the old gas-making and coke-oven methods, with equal amounts or" coal.

It will be noted from the chart, that this very important hydrocarbon liquid can, after it has performed its function, be reclaimed in the recovery of the primary tar oils, and can be returned cyclically, in the process, as can the pitch.

The first fractions, the light oils, are taken off between to 170 0., having a specific gravity of about .860, and include naphthas, benzol, toluol, xylol, some phenols.

The second fractionating stage, between 170 and 270 0., recovers the middle oils, having a specific gravity of about .970, and includes homologues of the phenolic series, phenol derivatives, cresols, creosote oils, carbolics, etc.

The third fractionating stage, between 270 and 360 0., recovers the heavy oils, with a specific gravity of about between .990 and 1.000, and besides some of the middle oil may include some anthracene oil.

Above 360 0., remains the residue of pitch or artificial asphaltic substance, and which may provide the resinic substance for the carrying out of this process.

The foregoing temperatures and gravities may vary within fairly wide limits, depending upon the basic materials employed, and therefore changes in carbonization and fractionating will suggest themselves to the operators. It is to be again stressed that the light oil, the hydrocarbon naphtha, as well as the pitch, may be returned cyclically, to the process.

If desired, said residue tar may be further treated for recovery of valuable constituents, or to refine the same.

It may be more economical or expedient when starting operation, to substitute for said coaltar naphtha, another naphtha having sufficiently like properties to enable its use herein, as for example some other hydrocarbon naphtha, say petroleum naphtha, having about the same boiling-points and being similarly fiowable at normal room temperature. Such a distillate may be of the aromatic, aliphatic or napthenic series or equivalent solvents, and to which may be added a small amount of phenolic compounds, cresols, xylenols, and the higher phenols, thus enhancing the solvency of the naphthas.

It will be found that the mass remaining after the agglutinizing, is spongy and porous, with a consequent irregularity of its cellular structure,

and this is ofgreat importance as it permits of. rapid passing of the vapors and gases from the briquettes into the condensors at relatively 10W temperatures. Such unobstructed volatilization of the tar vapors protects the briquettes from severe secondary decomposition and loss of very valuable primary tar oils. The usual swelling of the briquettes at the plastic stage of carbonization, generally caused by the accumulated and entrapped gases and vapors between 350 and 450 C., is eliminated, and localized overheating of hydrocarbon vapor into pyrogene decomposition is eliminated.

Other advantages obtained by the increasing of porosity of the coal are that there results accelerated and economical conversion of the coal, besides the unobstructed passage of vapors, without overheating.

If desired, the coke remaining after carbonization as above described may be treated further, and preferably while still hot, by transferrence while under exclusion of air, to a suitable coking retort, and gases extracted for further treatment.

It is well known that in crushing coal so as to pass through a standard mesh 20 to 30 per inch, about one-third to one-fourth of the coal will be reduced to dust of a fineness sufiicient to pass through about a 200 mesh screen. Since this proportion of crushed coal to dust is about the same proportion used in my invention, the process is very economical. Further, it is not necessary in making a paste by adding a hydrocarbon oil and resinic substances to the dust to first separate the dust from the coarse particles of coal; as the dust will be taken into suspension by the hydrocarbon oils without such separation.

Having thus described my invention, it is obvious that various immaterial modifications may be made in the same without departing from the spirit of my invention; hence I do not wish to beunderstood as limiting myself to the exact process herein set forth and described, except as limited by the state of the art to which this invention appertains, and by the claims hereunto appended.

What I claim as new and desire to secure by Letters Patent is:

1. A method of converting highly bituminous coal into coke briquettes comprising crushing the coal to pass a 30 to 40 mesh screen, to provide relatively coarse particles, preparing additional coal to pass an approximately 200 mesh screen, to provide pulverized particles, adding liquid 7. naphtha to the pulverized coal in the proportion of about 20 gallons of naphtha to 350 kilograms of pulverized coal, adding pulverized pitch of about the same fineness to the pulverized coal and naphtha, mixing and agitating the pulverized coal, naphtha and pitch in the absence of water to form a paste, adding to the paste two to three times as much by weight of the coarse coal particles, with respect to the amount of pulverized coal in the paste, intermixing the coarse particles and paste by a combined rolling, crushing, grinding and kneading action at room temperature, adding enough water to maintain fluidity during the intermixing, continuing the rolling, crushing, grinding and kneading for about 15 minutes, whereby the mixture becomes rubbery and slab-like, pressure-molding such rubbery and slab-like material into briquettes, and carbonizing said briquettes.

2. A method of converting highly bituminous coal into coke briquettes comprising crushing the coal to pass a 30 to 40 mesh screen, to provide relatively coarse particles, preparing additional coal to pass an approximately 200 mesh screen, to provide pulverized particles, adding liquid naphtha to the pulverized coal in the proportion of about 20 gallons of naphtha to 350 kilograms of pulverized coal, adding pulverized pitch of about the same fineness to the pulverized coal and naphtha, mixing and agitating the pulverized coal, naphtha and pitch'in the absence of water to form a paste, adding to the paste two to three times as much by weight of the coarse coal particles, with respect to the amount of pulverized coal in the paste, intermixing the coarse particles and paste by a combined rolling, crushing, grinding and kneading REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 332,613 Kelly Dec. 15, 1885 755,278 Cruikshank Mar. 22,1904 857,287 a Jordan June 18, 1907 1,430,386 Komarek 1 Sept. 26, 1922 1,512,427 Trent Oct. 21, 1924 1,561,322 Goskar Nov. 10, 1925 1,618,248 Walton Feb. 22, 1927 1,647,075 Bowen Oct. 25, 1927 1,667,906 Strafford May 1, 1928 1,825,756 Reynard Oct. 6, 1931 1,842,132 4 Trent Jan. 19, 1932 1,899,808 Kern Feb. 28, 1933 1,899,809 Kern Feb. 28, 1933 1,929,860 Trent Oct. 10, 1933 FOREIGN PATENTS Number Country Date 274,046 Great Britain Aug. 24, 1928 421,556 Great Britain Dec. 24, 1934 448,622 Great Britain June 8, 1936 521,152 Great Britain May 14, 1940

Claims (1)

1. A METHOD OF CONVERTING HIGHLY BITUMINOUS COAL INTO COKE BRIQUETTES COMPRISING CRUSHING THE COAL TO PASS A 30 TO 40 MESH SCREEN, TO PROVIDE RELATIVELY COARSE PARTICLES, PREPARING ADDITIONAL COAL TO PASS AN APPROXMATELY 200 MESH SCREEN, TO PROVIDE PULVERIZED PARTICLES, ADDING LIQUID NAPHTHA TO THE PULVERIZED COAL IN THE PROPORTION OF ABOUT 20 GALLONS OF NAPHTHA TO 350 KILOGRAMS OF PULVERIZED COAL, ADDING PULVERIZED PITCH OF ABOUT THE SAME FINENESS TO THE PULVERIZED COAL AND NAPHTHA, MIXING AND AGITATING THE PULVERIZED COAL, NAPHTHA AND PITCH IN THE ABSENCE OF WATER TO FORM A PASTE, ADDING TO THE PASTE TWO TO THREE TIMES AS MUCH BY WEIGHT OF THE COARSE COAL PARTICLES, WITH RESPECT TO THE AMOUNT OF PULVERIZED COAL IN THE PASTE, INTERMIXING THE COARSE PARTICLES AND PASTE BY A COMBINED ROLLING, CRUSHING, GRINDING AND KNEADING ACTION AT ROOM TEMPERATURE, ADDING ENOUGH WATER TO MAINTAIN FLUIDITY DURING THE INTERMIXING, CONTINUING THE ROLLING, CRUSHING, GRINDING AND KNEADING FOR ABOUT 15 MINUTES, WHEREBY THE MIXTURE BECOMES RUBBERY AND SLAB-LIKE, PRESSURE-MOLDING SUCH RUBBERY AND SLAB-LIKE MATERIAL INTO BRIQUETTES, AND CARBONIZING SAID BRIQUETTES.

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