US3184293A - Carbonaceous shapes - Google Patents

Description

May 18, 1965 J. WORK ETAL 3,184,293

CARBONACEOUS SHAPES Filed May 24. 1960 2 Sheets-Sheet 2 COA/D/T/ N59 36 BLENDEP l 51% INVENTORS. 0 r L/OS/AH Vl a m Poss/Pr Z'JOJEPH. LbH/vHBL/QKE.

BY I r 4 WW ATTORNEYS.

strong carbon walls.

United States Patent C) 3,184,293 CARBONACEOUS SHAPES Josiah Work, New Canaan, Conn, Robert T. Joseph,

Richboro, Pa., and John H. Blake, Boulder, Colo., as-

signors to FMC Corporation, a corporation of Delaware Filed May 24, 1960, Ser. No. 31,317 3 Claims. (Cl. 4423) This application claims the coke shapes produced by the processes of our co-pending patent application, Serial No. 821,137, now Patent No. 3,140,241, filed June 18, 1959, and is a continuation-in-part of said application.

This invention relates to carbonaceous shapes, such as extrusions, briquettes, and other shapes useful, among other uses, in the smelting of phosphorus and other ores, i.e., as a source of metallurgical carbon and for carrying out chemical reactions.

High temperature by-product coke is the form of carbon used chiefly for metallurgical purposes. Conventional coking processes entail heating so-called coking coals to high temperatures in the absence of air for long periods of time, usually from 16 to 72 hours. As coking coals are heated, they soften and become fluid with a consistency of a thick pitch. This softening is accompanied by the generation of gaseous components which are present in the parent coal as low molecular weight materials or which decompose as the temperature of the charge passes from ambient to elevated levels necessary for substantially complete devolatilization of the coal to produce coke. The result is a mass of solidified froth of independent bubbles separated by rather hard and Before use, this mass of froth is broken up, giving a wide range of particle sizes, the individual pieces of which are irregularly shaped.

The production of coke shapes by crushing coke or carbonized coal particles, mixing the crushed coke or carbonized coal particles with coal tar or pitch binders, compressing the mixtures in molds, and heat treating, has been proposed. Such heretofore known coke products are referred to herein as formed coke products. As heretofore produced, formed coke products are heterogeneous. When examined microscopically, the portions of the product derived from the binder are readily discernible and can be distinguished from those portions derived from the coke or carbonized coal mixed with the binder. In formed coke products the carbonized coal or coke particles have undergone a more extensive heat treatment than the binder carbon and are therefore less reactive than the binder, with the result that the binder reacts more readily than the remainder of the product and the product disintegrates, for example, in use as a source of metallurgical carbon. This explains the failure of formed coke products as substitutes for conventional metallurgical coke to perform satisfactorily for metallurgical purposes,

Only by prolonged baking at high temperatures can formed coke products be produced which will react in a manner so that they do not disintegrate when used for metallurgical purposes. Such prolonged heating, however, reduces the reactivity of the products. The combination of high reactivity and uniform reactivity of the masses of formed coke products was heretofore not obtainable.

It is among the objects of the present invention to provide novel coke shapes possessing the combination of high strength, homogeneity, high reactivity and uniform reactivity, eminently satisfactory for use as a source of metallurgical carbon and for other uses.

It is another object of the present invention to provide such coke shapes having still other desirable properties such as high surface area.

It is a further object of the present invention to provide such coke shapes having unusually high reactivity with carbon dioxide and steam.

Other objects and advantages of this invention will be apparent from the following detailed description thereof.

The carbonaceous shapes of the present invention have a combination of properties not available in heretofore known carbonaceous materials, the more important of which properties are:

(a) High physical strength;

(b) High chemical reactivity;

(c) Uniform reactivity, i.e., substantially the entire masses of the shapes react at substantially the same rate and are consumed evenly and uniformly;

(d) Homogeneity;

(e) Exceptionally high surface area;

(f) A surprisingly high hydrogen content or, stated otherwise, a surprisingly low carbon to hydrogen ratio on a weight basis;

(g) Surprisingly high real density taking into account their high hydrogen content; and

(h) A markedly different inter-molecular structure of the carbon, as compared with carbon in other cokes derived from coal, evidenced by the markedly greater helium density values relative to the real density values and thus demonstrating the presence of appreciable amounts of carbon (per unit weight) having inter-molecular spacing too small to admit water but large enough to admit the much smaller helium atom,

The high physical strength of the products are demonstrated by their tumbler index value, which is at least 90, preferably from to 98, and their resistance to crushing value which is at least 3,000, preferably from 3,500 to 8,000, and may be as high as 18,000 pounds per square inch. The tumbler index values in this specification are determined in accordance with the procedure given in ASTM-D44l modified somewhat in view of the nature of the materials being handled. Thus the procedure involves placing a gram sample in the tumbling machine consisting of a circular 3 vane steel drum, 36 inches inside diameter and 18 inches in inside length, made of plate at least A1 inch in thickness, rotating this drum at 53 rpm. for 10 minutes, then emptying the drum into a receiver from which the material is poured onto a No. 6 Tyler mesh screen which is shaken by hand until all 6 material passes through the screen. The weight in grams retained on the screen is the tumbler index value.

The resistance to crushing value is determined in pounds per square inch by measuring the gauge reading at which a 1% inch by 4 inch cylinder crushed under hydraulic pressure applied to its flat surface.

The high chemical reactivity is exemplified by the reactivity of the shapes with carbon dioxide which, under the test conditions hereinafter described, is at least 10, preferably 10 to 70; also with steam which, under the test '2 0., conditions hereinafter described, is at least 20, preferably 20 to 90. e

The reactivity with carbon dioxide hereinafter referred diameter. The reactivity with steam hereinafter referred to as CRH O is'measured b'ythe am-ount of 'cokesized to pass through a 20-mesh but retained. ona 28-mesh TABLE .1

Physical strength: a Tumbler indexAt least 90, preferably 90 to .98.

; Resistance to crushing, lbs. per sq. in.-At least 3,000,

' preferably 3,500 to 8,000..

,(b) Chemical reactivity; e V CR CO At least 10, preferably to 70.

, CRH' O-At least 20, preferably to 90. (c) Reacts uniformly. J (d) Homogeneous. (e) a Surface area, BET, nitrogen, square meters per Tyler screen consumed in one hour in a stream of steam at 7 min. in, atube of about 1 inchin'side diameter.

In both the CR-CO and CR,'H O tests each sample 825 C. and passed over the sample at a rate of 133ml! was crushed and screened. 500 mg. weighed 'out. one 1 balance of 0. 1 sensitivity were placed in a Gooch crucible cut down to fit with clearancein the silica tube of the furnace. The sample made a bed of inch in diameter and A inch deep. The samples were flushed clean of .air by passing argon thereover at a rate of 370 ml./ min. for

ten minutes. 7

The uniformity of chemical rea ctivity'of the shapes of this invention is evident from the uniform consumption The homogeneity. of the productis' evident from microscopic examination; the carbon derived from the binder and that derived from the calcinate char particles bonded with the binder to form the products, as hereinafter more fully described, cannot be distinguished by visual means When a shape is split-or fractured,'the fracture invariably goes through the calcinate char particlesqrather than around them, i.e., the shapes fracture through the grain boundaries rather than through the binder. f "1 The products have an exceptionally high surface area asexplified by a SAN value of at least 100 square meters 7 per gram, preferably from 100 to SOO s'quare meters per' gram. The SAN value is the surface area determined by the standard Brunauer, Emmett and Teller method, using gram-At least 100, preferably 100 to 500. Carbon to'hydrogenratimwt. basis-82 to 114. (g) Real density -1.70 to 2.1. w (h) Carbon content, moisture and ash-free, by weight At least 95%. (i) Volatile material, content, ash-free, by weightNot more than 3%. e (j) Helium density- 2.3 to 4 and a ratio of helium density to real density of 1.35 to 2.35. V (k) The products may be made of uniform size and, within limits, of any desired size best fitted for their intended use, for. example, from 10 inches down to /2 inch. V (l) The products have a bulk density of from to 55.

In Table ZJwhich follows is given a comparison of the chemical and physical properties ,of commercial by-product' coke with six examples of the products of this invention, which examples are identified as I, II, III, IV, Vand VI. The examples of this invention, I to V1, inclusive, were produced from" different ranks of coals, ide'ntifiedin Table 3 below by the process disclosed" and claimed in our aforesaid co-pending patent application and thefconditions and the steps of which process. are given in Table 4 below.

In Table 2 ASG is the apparent-specific gravity and is obtained by weight measurement. of the mercury displaced by 10 grams of the solid shapes. e a

BD isithe bulk density in pounds per cubic foot de- .termined bythe procedure given in ASTM-D-29l.

nitrogen asthe gas being adsorbed The values are given in square meters per gram.

The carbon to hydrogen ratio on a 'weight basisof the products ofithis invention are within therange of from I the standard water displacement method. 'The values are given in grams per cubic centimeters. ti V The products on a moisture and ash f ee basis have a carbon content of at least by weight, a volatile material content on an ash-free basis of not more thanf3% by weight, and a helium absorption or helium density of. from 2.3 to 4. By heliumdensity is meant'the apparent" helium displacement as 'dete'rmined by the standard method involving displacement .ofhelium. The valves are given in grams per cubic centimeters; .theseyalues were determined 'by the techniquedescribedon pages 15,

scribed.

. TI is the tumbler indexdetermined as hereinabove described;

RC is the resistance tocrushing in pounds per square inch determined ashereinabove described.

MH is the'Mohs hardness indexrneasured using a standard Mohs hardness scale."

SAN is the surface area as hereinabove described.

RDis the real density determined "as hereinabove de- HD is thefheliurndensity determined as hereinabove described;

HD/RD isthe rat o a helium" density to real density and is indicative of the nature of the inter molecular structive is thecarbon of helium.

X'-ray d, 002 gives thevaluesiof the inter-planar distureof the carbon. The higher theratio the more absorp- V tance (d spacing at the 002 index) in'A. units. This value indicates the distance between thefmolecular units or platelets as determined by the scatter of X-rays from a constant source and of a constant frequency as theibeam of; these rays scans the powdered specimen overan angularrange of approximately 001 is the orientation jndexfactor which is the ratio of- I-;, to I whereI 'is the uncorrected peak intensity of the 16 and 17 of the thesisfentitled Some Physical and Chemical Properties of Carbon and GraphiteElectrodes'f Prepared from Anthracite,.dated'lanuary, 1959, by Ifwin Geller of the Graduate School of Pennsylvania stateEUniyersity, Department of Fuel T technology. I j I V Summarizing, theproperties of the carbonaceous'shapes embodying this invention are given: in Table l which follows.

002'region'0f the X -ray1ditfraction as'recorded and '1 is theinterpolated background intensity at the same d value.

. {VM means" volatile matter} i 1 FC means free carbon.

'MAF means on a moisture and ash-free basis.

The other abbreviations underjUltimate Analysis are r the chemical symbols 'fo'r 'the elements identified thereby C /H is the carbon to hydrogenweight ratio. V

"' H /C is the hydrogen to carbon-atomicratio.

TABLE 2 Commercial Test I II III IV V VI toy-product coke CHEMICAL REACTIVITIES (JR-CO2 80. 8 10 31 28. 7 14. 8 58 2 (DR-H O 52. 4 26 55 29. G 26 54 5. 3

PROXIMATE ANALYSIS (MAF, WT. PERCENT) V.M 2.3 2.8 2.4 2.6 3.0 3.0 0.9 F.C 97.7 97. 2 97. 6 97. 4 97.0 97.0 99.1

ULTIMATE ANALYSIS (MAF, WT. PERCENT) 108 82 101 114 92 Infinity n/Oa 0.133 0.111 0.146 0.119 0.105 0.131 0 Ash (dry, Wt. percent). 5.91 2.89 6. 24 11.13 11.74 22. 06 10. 52

It will be noted from the above table that the real densities of the six examples range from 1.804 to 2.098; the helium densities range from 2.97 to 3.99, and the ratio of helium densities to real densities range from 1.54- to 2.02.

The chemical reactivity in air of the products of the above examples was determined by placing a sample of each product over a Bunsen flame burning propane and air in such proportions that the blue cone was 7 cm. long and ended 1 cm. below the coke shape being tested. The same test was applied to commercial by-product coke. Each of the samples of the above examples was uniformly consumed and did not spall. The by-product coke, on the other hand, burned unevenly.

The products of the above examples and by-product coke were examined under microscopy at magnifications of 500 and x. All of the examples had an open and connected pore structure. In the case of by-product coke, on the other hand, the pore structure was open and unconnected. The products of the examples had a homogeneous appearance. No visible difference between coke derived from the binder and that derived from the calcinate was evident under this magnification. In the case of by-product coke, on the other hand, the product was non-uniform in character.

The shapes of this invention under conditions of rapid reaction such as with air at 600 C. (a dull red heat) react cleanly from the outside inward, i.e., the inside of the piece is substantially unaitected by oxidation while the reaction zone on the outside surface is thin, of the order of mm. thick.

In the accompanying drawing:

FIGURE 1 shows a box diagram of the sequence of steps of the process resulting in the compressed coke shapes embodying the present invention, and

FIGURE 2 is a flow sheet showing a preferred arrangement of equipment for carrying out such process.

As disclosed in our co-pending application, the carbonaceous shapes embodying the present invention are produced by a procedure involving the following stages:

(1) The coal, if not already finely divided, is ground, for example, in a hammer mill, to a particle size small enough to be readily fluidized.

(2) These ground coal particles are pretreated (catalyzed) in an environment of such characteristics that as the parent coal passes into and through the succeeding carbonizing stage a reduction in the hydrocarbonaceous volatile content and a polymerization of the remaining hydrocarbonaceous matter of the coal takes place and this without destroying the original physical structure of the coal. This effect is presumed to involve the formation of catalysts of peroxide of hydroperoxide nature which are formed from a portion of the contained oxygen in the parent coal and/ or from oxygen derived from the steam and/or air atmosphere in which this step is carried out.

This step must be carried out within a certain temperature range which varies from coal to coal, which is dependent, in part at least, on the time the parent coal is subjected to such temperatures, and which is limited by the distinguishable phenomena hereinafter set forth. The upper temperature limit, regardless of time, is that temperature above which the distilling vapors form tar when condensed. The lower temperature limit is that temperature at which contained moisture is evolved from the parent coals.

The residence times between these temperature limits necessary to accomplish this catalyzing effect depends on the processing treatment employed, the temperature within the limits stated and the rank of coal being processed.

Two further but important secondary eifects of this stage, incidental to the primary purpose of catalyst formation, are:

a. The moisture content of the parent coal is reduced to limits found necessary for proper operation of the carbonizing stage, usually to 2% or less;

b. Where such exist, the coking and caking tendencies of the parent coals are destroyed by a small addition and/ or recombination of oxygen, derived from the parent coal or the atmosphere in which this stage is conducted, to form carboxylic groups as are found in humic acids.

These catalyzed coal particles are pyrophoric and should be handled in transport by procedures that will prevent undesirable oxidation.

This stage, which results primarily in effective catalyzing of the coal, is hereinafter and in FIGURE re-, ferred to as the Catalyzing Stage. The products are referred to as Catalyzed Coal.

"cooled to a temperature at which subsequent blending with the binder is efiected, or to. below 400. F., or to the temperature at which the calcinate is to beused when (3) The aforementioned catalyzed coal particles are subjected to further heating at rates and residence times, hereinafter set forth, to produce the desired density and reactivity characteristics in the calcinate product, i.e., that resulting from the subsequent stage.

The purpose of this third'stage is to carry on that type of polymerization which is promoted and directed by the catalysts (presumed to be formed in'the catalyzing the calcinate is to be utilized as such. If used at a lower temperature, such cooling may be effected by introducing the hot calcinate into a fluid bed 'maintained at the temperature to which the calcinate is to be cooled, or accomir plishing this stepwise by use of two or more fluid beds if stage) in such a manner that a'substantial portion of the parent coal constituenst are retained in a form of the parent coal structure While, at the same time, an amount of these constituents (predicated on the predetermined environment of this stage) is evolved as vapors which may be condensed to form tars and gases for use in subsequent demands of the process. This stage effects a reductionlin What is conventionally called the volatile combustible matter (VCM) in the parent coal. y V

The necessary heating rates and residence times may be achieved by introducing the catalyzed coal into a fluid bed reactor where the temperature rise is' effected heat economy so dictates; The effect of such cooling is'to reduce the loss of product by oxidation upon contact with air, and at the same time to maintain the structure of carbon surface by preventing this oxidation. f

Hereinafter and in FIGURE 1 this stage is referred to as the Cooling Stage, and the product'from this stage is referred to as the Calcinate. V

These calcined particles are pyrophoric and should be handled in transport by procedures that will prevent undesirable oxidation.

(6) The calcinate is mixed with a binder (preferably the tar produced in carbonizing the parent coal after this tar has been treated by heat and air-blown to a prescribed softening point hereinafter disclosed) in such a manner that all thecalcinate particles are surface-coated with the practically instantaneously, and where the residence time;

tion of such a portion of the catalyzed coalf particles as is needed to supply the heat demands of the reaction, and control of this combustion-is effected by admitting only thatamount of oxygen (preferably asfair) as Will support this prescribed level of combustion.

These char particles are pyrophoric and should be hanled in transport by procedurethat will preventundesire;

able, oxidation. a

. Hereinafter and in FIGURE 1 this stage'is referred to as the Carbonizing Stage and the solidprioduct from this stage is referred to as Char.

(3:1) The condensed, ire,co,vered tar vapors from the carbonizing stage are treated to produce a binder suitable for subsequent blending with the calcined char. This low that level where the passage of gases (air orf'steam) binder, aminimum of adsorption occurs,and the calcinate and'binder areso intermingled that subsequent processing causes copolymerization of the binder and calcinate. This'reaction is exothermic; the temperature of blending or mixing should be maintained at not more than through the tar. mass will cause distillation of light ends in excess of 5% by weight of the dry tar being sotr'eated." This treatment is continuedjuntil a suitable viscosityi'ncreaseis obtained, as hereinafter disclosed,

Whenbinders derived'from other sources are used,"this provide thedesire'd temperature, must be done in anatmosphere containing'no more of such active gases as will produce the heat and no more carbon dioxide than will bejproduced by the ,cor'nbustionfof, that part of the char particlesnecessary to supply the heat demanded by this reaction. a 1

These calcined particles are j pyropho ric and should be. prev n handled in transport by procedures'that will desirable oxidation. 1

30 F to 60 F. above theASTMfsoftening point of the binder used.

This stage, which effectsfthe blendingof binder and calcinate, is hereinafter and in FIGURE 1 referred to as the Blending Stage and the product is referred to as the Blended Material.

(7) The blended material is'subjected to a compacting operationto form any shape demanded (as by briquetting, extrusion or any similar process) wherein the applied pressure on the blended mass is of such magnitude that the shape, when freed from the mold or die, Will retain the 'form and be capable of withstanding abuse and handling at normal and elevated temperatures.

This product is 'pyropho'ric and unstable and consequently should not be stored;

Hereinafter and in FIGURE 1 this stage is referred to as the Green Shapes (briquettes, extrusions, etc.).

(8) The green shapes from the forming stage are subjected to further processing by heating in an oxygen-containing' atmosphere until copolymerization of the binder and calcinate has been completed. In this-stage the residence time andater'nperature are interrelated. This curing can be accomplished at room temperature in a matter of days, or at elevated temperatures, hereinafter given, in a matter. of 60 to minutes. Longer times at elevated temperatures affect the strength adversely. Accelerators can be used to reduce the time.

The minimum quantity'of oxygen required in the curing atmosphere is'2.5% by volume; more can be used, if desired, up to a maximum 'of 21% under the conditions hereinafter set forth. i V

The purpose 'of this curing stage is to promote maximum polymerization, presumably by peroxide or hydroperoxide catalyzationg b'etween the binder and calcinate andlthereby prevent formation of coke from the binder alone. This copolymerization apparently acts to de- ;crease'the vapor pressure of the binder-calcinate system ,tosuch a level that, in the subsequent stage, col e is formed 6 from, the copolymers preferentially to disillation of the highvapor pressure components of the original binder.

Hereinafter and in FIGURE 1 this stage is referred to as the .Calcining Stage and the product from this stage is referred to as Hot ,Calcinate. 7

This product is pyrophoric.

' Hereinafter andin FIGURE 1 this" stage is referred to,

as the Curing Stage andthe product from this stage is referred to as fC ured Shapes (briquettes, extrusions,

eto). 1

produce the massive carbonaceous material final product. This is best accomplished by coking in an atmosphere substantially free of such reactive gases as carbon dioxide (which will react with the carbon of the massive forms to produce carbon monoxide and reduce yield), oxygen (which will react with the massive shapes to produce carbon monoxide and reduce the yield) and steam (which will react with the carbon of the massive shapes to produce hydrogen and carbon monoxide and reduce the yields).

A secondary detrimental eflect of such side reactions is the partial consumption of individual shapes causing undesirable non-uniformity of size and surface.

This treatment must take place at a temperature sufficient to reduce the volatile combustible content of the final product to 3.0% or less.

The time necessary to accomplish these aforementioned ends is dependent on the temperature and is the time necessary for the coking reaction to reach that stage of completion at which the coke shapes have the desired strength.

The heat for this reaction is preferably supplied by direct contact with hot inert gases (for example, carbon monoxide or hydrocarbon gases produced in earlier stages) as in a shaft or on a moving grate. However, any other means of raising these cured shapes to the temperatures dictated by the specifications for the final product may be used. Such means may be direct or indirect, as by gas contact or by radiation from externally heated walls, or by direct radiation sources.

The shapes, after having been subjected to the hightemperature treatment, must be cooled, preferably but not necessarily in the same apparatus, but in any case in an atmosphere free from reactive gases, as previously described, to such a temperature that harmful and yieldconsuming reactions with reactive gases do not take place.

Hereinafter and in FIGURE 1 this stage is referred to as the Coking Stage and the product from this stage is referred to as Coke Shapes (briquettes, extrusions, etc.).

These shapes are exceptionally uniform in that the product, from boundary to boundary, is a homogeneous entity, as indicated visually by optical microscopy and chemically by the uniform, homogeneous consumption of the shape from all dimensions in any reactive medium. These shapes have a high strength (denoted by resistance to compressive pressures on a 1% diameter x /1 high cylindrical form) of at least 3,000 pounds, a high bulk density, exceptional resistance to abrasion, and unusually high surface area for such high strength.

The characteristics listed are not all-encompassing. These final coke shapes possess other desirable qualities which will become apparent from the description which follows.

The preferred conditions generally applicable to lignites, high-volatile non-coking coals, coking coals and anthracites of each of the above stages will now be described.

The grinding stage In the practice of this invention, the coal, if not already of the required finely divided size, may be ground by any standard grinding and sizing technique to produce a natural distribution particle size, substantially all of which passes a No. 8 mesh screen and at least 95% of which is retained on a No. 325 mesh screen and with a minimum quantity of fines of a size which would escape from the cyclone of the fluidizing bed reactors. This is readily accomplished by grinding in a hammer mill.

The catalyzing stage These finely ground parent coal particles are first subjected to pretreatment, desirably in a fluidized bed, but alternatively in a dispersed phase, to promote, presumably, the formation of peroxide and hydroperoxide catalysts. This is best accomplished in an atmosphere containing oxygen, the concentration of which will vary inversely with the oxygen concentration of the coal being so catalyzed. The practical range is 1% to 20% by volume in the entering fluidizing medium, depending on the rank of the coal. For low-rank, non-coking coals, a volume of oxygen at or near the lower limit of this range is employed, e.g., from 1% to 8% by volume; for coking coals, a volume of oxygen in the upper part of this range is used, e.g., from 8% to 20% by volume. In general, the concentration of oxygen used Will be that optimum quantity of oxygen which will add to the coal matrix and thus provide a source of oxygen for catalyst formation and inhibition of agglomerating tendencies, if present, without causing an uncontrolled combustion in this catalyzing stage or in the later stages of the process.

In this catalyzation of non-coking coals, including lignites, the fluid bed is normally maintained at a temperature of 250 to 500 F.; for coal possessing caking and coking characteristics, in order to promote the secondary effect of destroying these characteristics, the bed is maintained at a temperature of 500 to 800 F. The maximum of the range is that point in temperature at which hydrocarbon vapors, the tar precursors, begin to be evolved. The lower limit is that temperature necessary to reduce the moisture content to 2% or less, or, in the case of coal with less than 2% moisture, that temperature at which oxygen can be added to the coal matrix.

In carrying out this catalyzation, the parent coal may be introduced into a cold fluid bed and subjected to a gradual rise in temperature to the range indicated. Preferably, the parent coal is introduced continuously into a fluid bed maintained at the desired temperature, wherein the heating rate will be of shock or instantaneous magnitude, for one second or less.

When heating the coal particles under fluidizing conditions, the coal particles should remain in the fluid bed for an average residence time of at least 5 minutes, and preferably from 5 minutes to 3 hours. This catalyzing may be accomplished in times as low as 10 minutes, or as high as 180 minutes, without the occurrence of deleterious effects on the final product. The temperature of catalyzation, within the ranges given, bears an inverse relationship to the residence time. In catalyzation of noncoking coals at temperatures in the lower portion of the range of 250 F. to 500 F., the times should be in the upper portion of the residence range. On the other hand, when operating at the higher temperatures, near 500 F., the residence time should be in the lower portion or" this time range. Similarly, when processing coking coals, longer residence times within the range of from 5 minutes to 3 hours are employed when operating near 500 F. and the shorter residence times when operating near 800 F. The times and temperatures of catalyzation for anthracite coals are substantially the same as for coking coals.

The fluidizing medium, desirably steam or flue gas dilute-d with air or oxygen, is introduce-d at a pressure of from 2 to 30 p.s.i.g. The fluidizing medium is introduced at a velocity to give the desired boiling bed conditions, e.g., from about 0.5 to 2 feet per second superficial velocity.

Heating of the finely divided coal particles in the fluidized bed may be effected by burning a small portion of the coal, by sensible heat introduced in the fluidizing medium, or by indirect heat exchange.

In lieu of effecting catalyzation of the coal in a fluid ized bed, the finely divided coal particles may be subjected to heating in a dispersed phase, i.e., dispersed in a suitable gaseous medium (e.g., flue gas, nitrogen, or carbon dioxide containing oxygen, within the limits heretofore prescribed) of sufficient velocity to maintain the particles in the dispersed phase rather than in the dense phase, as in a fluidized bed. Utilizing dispersed-phase heating, non-coking coals are heated to a temperature of 350-750 F. for about 3 seconds. Coking coals are heated to a temperature of 750-1G00 F. for about 3 seconds. I V a Catalyzation, as hereinabove described: 1 (1) Conditions the parent coal so that in further processing in the succeeding stages, a c-on'trolledfamount of polymerization occurs which effectively increases the strength and thickness or" the pore walls while permitting a predetermined amount of the coal constituents to evolve as gas and vapors, which vapors are subsequently condensed to tar'to fill the demands of the total process;

'usually 0.5 to 2 feet per second and, desirably, a pressures consistent with the smooth operation of the whole process, e.g., 2 to 3.01 -p.s.i.g., preferably about 5 p.s.i.g.

The material in the bed is maintained at. the aforementioned bed temperature for to 60 minutes. The residence time at this point is a source of control of the chemical reactivity and other characteristics of the final fcalcinate or massive shape and isdetermined by the specification set for the final calcinate or massive shape derived (2) Effects the removal of contained moisture When hydrous coals are treated; 3) In the case of coals glomerate, the treatment inhibits this tendency.

These effects are accomplished without sacrifice otthe 'density-ot-structure characteristic. of. thepa-rent coal. 7

The carbonizing stage Carbonization is carried out by subjecting the catalyzed coal particles to a further heat treatment in a fluidized which havea tendency to ag bed where the heat requirements are supplied, preferably, by the oxidation of a limited amount of the catalyzed coal or of the hydrocarbon vapors derived therefrom.

This oxidation is controlled by the admissionof only that produce aichar having the detar consistent with the quantity .of binder required for blend specifications;

. 0. So .controlled as to produce the maximum of tar',f which, in the case of anthracite or other'low volatile coals,

may be insufiicient to satisfy thebinder requirements under paragraph b. I 7

Optimum conditions of the carbonizingstages will var'y' from coal to coal and may be determined for each rank of coal processed by prior laboratory evaluation in benchscale apparatus. 7 e

Temperature and residence quantity and this temperature is the same as the upper limit of the catalyzing stage for any given coal, i.e.,

coals. V x

The upper 1imit:of temperature isthat temperature 7 above which the expanding coal particles form cracks,

fissures and bubbles to such an extent that retraction to the size and shape of the original coal particle. cannot' occur. This upper temperaturelimit is approximately l1501200 F. In general, the higher the temperature for coking coals and 500 F. for non-coking fiom the calcinate; a

In the case of coals belowthe rank of anthracite, suf cient binder is producedto supply the needs of massive formation With anthracites such is not the case; the

carbonization st'ep partia1y de-gases and rearranges the anthracite structure for further't'reatment in succeeding stages of the process. i

The carbonization may be carriedout'as a continuation of a batch-operated catalyzing step wherein, particles 'beingeatalyzed having been held at the desired temperature for the specified residence time, the temperature of the bed is raised as rapidly as, the reaction ,of the oxygen content ofthe' fluidizing medium ,with the bed will achieve carbonization temperatures; Or, preferably, this carbonization may be, carried out by continuously feeding the catalyzed coal fromjthe catalyzing stage directly into a fluid bed maintained at the carbonizing temperatures as previously described. Inthis casethe heat transfer rates within the bedare of such a magnitude as to effect instantaneous shock heating of. the particles.

Unless thenparent eoal particleshave been treated as prescribed in the catalyzing stage, irreversible expansion time are critical. Thellower limit of temperature is that temperature at Which the activated coal begins to evolve tar-forming vapors in of' the particles'results from'non-elastic rupture and explosion of the pore Walls. The resulting chars, While useful as boiler fuels, .cannot, be further processed to produce the .calcinate or massive shapes that will be competitive with or superior to the cokes from .by-product, beehive or similar ovens. 4

It ismonlyby following. the sequence of stages above described'that high-density, high-strength calcinate particlestwhich are. subsequently formed into homogeneous stable shapcs.). result 7 a 7 Recovery'tmii preparationpf the tars That controlled portion of the coal constituents which is evolved as gas and vapor from the coal particlesmay be processed toproduce tars and gas for use in the process,

The. vapors may be cooled by'direct contact with a recycling water spray to such'a temperature that about of the vapors are condensedto'tar. Theuncondensed 20% goes forward throughconv'entional heat exchangers and is cooled to about 40 F. above thecooling medium temperature which circulates indirectly over' the heat exchange surfaces at which temperature some further condensation takespla'cc'. The two condensates are com- 'bined tov give the total wet tar which is allowed to settle, and the water is decanted to leave. a decanted tar of about {4 6% moisture content.

Alternatively, the gas and'vapor. stream may be cooled V by direct spray,- or, conventionally, through indirect heat of carbonization (within the lower and. upper limits the greater the quantityof tar. produced; 7,

The fiuidizing gas should enter the bed ata temperature not much below the temperature of the fluidized bed and not morethan 20 F. above thisj temperature; if this fiuiclizing medium is introduced at a muchxlower tern: perature than the bed, more of the catalyzed coal and hydrocarbon ivapors will have to be burned'in order to V supply the heat necessary Qtoraise the fiuidizing medium to bed temperature, thereby reducing product yields, If

the fluidizing gasesenter the bcd ata temperature of more than 20F. above thetemperature ofthe bed, weak non: uniformlcharresults;

The fiuidizing medium isjintroduced at such superficial velocities as will'eiiect the idesired fiuidi z'a-tion pattern;

exchangers to such temperatures aswill totally condense 1 thetar precursors to tar and a llowonlythe normally non- 1 condensable gases, such as methane, etc.,to leave the heat 7 exchangers. This results in'aftotal condensate, not separate fractions. This totalcondensate 'is then decanted in the manner'heretoforedescribed'.'

Blowingfthe{decanted-tars so formed simultaneously dehydrates the tar to .a water content of 095% and increases the tar'viscosity to the desired softening point. A softening point withintherange of to 225 F., preterably to 15051-1 (ASTM ringand ball) .is satisfactory'f or usei'as theibihder.

'Y-This blowing is accomplished by the injection of air steamrnay be used butisnot as effective as air). through asuitabl e 'spar'ger into the'decanted air. This tar is main -tained atfa temperature above the condensation tem-' 13 .perature of the steam, but below that point at which distillation of the tar light ends exceeds approximately The retained light ends are converted to binder of proper viscosity during the flowing treatment.

This viscosity increase may be accomplished by incorporating catalysts into the tar after dehydration. Suitable catalysts are organic peroxides, such as benzoyl peroxide, inorganic catalysts such as sulfuric acid, boron trifluoride or its complexes, aluminum chloride, etc. The usable catalyst concentration may vary from 0.1% to 2% depending on the tar, the catalysts and the viscosity range desired.

T he calcining stage The char particles from the carbonization stage are further heated to reduce the amount of volatile combustible matter remaining in the end pro-duct to below 3%. Desirably, this calcination is achieved in a fluid bed operating at that minimum temperature necessary to achieve this reduction, i.e., from about 1400 F. to 1500 F., and for a residence time of from about 7 minutes to about 60 minutes. Higher temperatures may, however, be used but not exceeding about 1800 F. At an operating range of 1500 F. to 1800 F. residence times in excess of 10 minutes effect a reduction in the chemical reactivity of the calcined product proportional to the length of the residence time in excess of 10 minutes. A secondary effect of this calcining is to increase the physical strength of the calcinate.

The residence times of the char in this stage are dictated by the specification of the final product and are more or less dependent upon the operating temperature. At minimum temperature, sufiicient residence time to reduce the volatile combustible matter to 3% is required. Practically, this limit is 10 minutes at about l4-O0 F. to 1500 F. and should not be less than 7 minutes even at 1800 F.

The fluidizing atmosphere necessary in this stage should be free of reactive gases such as carbon dioxide or steam. Oxygen can be tolerated only in such an amount as is demanded by that oxidation rate of the char necessary to supply the heat demands of this stage. This oxygen is most practically obtained from air introduced as part of the otherwise chemically inert flu-idizing medium, and the concentration of air for this purpose in these entering gases shall not exceed 70% The remaining components of the fluidizing medium may be carbon monoxide, hydrogen, nitrogen and flue gas in which carbon dioxide and water have been reduced to carbon monoxide and hydrogen by previously passing the flue gas over a bed of hot carbon, or otherwise.

.This fluidizing medium should be introduced at such pressures as are consistent with smooth operation of the fluidization process; a range of from 0 to 30 p.s.-i.g., preferably about 2 p.s.i.g., is satisfactory. The velocity of this medium should be consistent with a proper fluidizing pattern, or the same as in the carbonization stage, e.g., 0.5 to 2 ft. per second.

It is advantageous to introduce the fluidizing medium at about the operating temperature of the bed. Lower than bed temperatures will demand increased oxidation of the char, with resulting deleterious effect of water vapor and carbon dioxide on the final product.

The heating may be accomplished as a continuation of the catalyzing and carbonizing stages, in the same batchoperated fluidized bed reactor, by raising the temperature of the bed to the desired calcining range, and holding the bed at that range until calcination has been completed. Or, preferably, the hot char may be introduced continuously and directly to a fluidized bed operating at the specified calcining temperature. In this case, the rate of heat transfer in the fluid bed is of such magnitude as to effect shock or instantaneous heating of the char to calcining temperature.

' Unless the parent coal has been treated as prescribed in the catalyzation and carbonization stages, this shock heating will shatter the particles, producing extremely low apparent density, high exploded fines. Such particles give evidence that the structure, density and fracture of the parent coal have been completely, adversely and permanently altered.

The calcinate produced by observing the conditions hereinabove described has the essential structure and apparent density of the parent coal particles.

The cooling stage The calcinate must be cooled rapidly and immediately to prevent loss of reactivity. This cooling, desirably, is effected in one or more fluidized beds, preferably two, in which the fiuidizing medium also serves as the cooling medium and in which the heat transfer rate is of such magnitude as to effect instantaneous cooling. Suitable cooling media are flue gas, nitrogen, or carbon monoxide, introduced at a temperature to effect the desired cooling and at a velocity to efiect the desired fluidization. The velocity may be substantially the same as that employed during the carbonization or calcination treatments. Cooling atmospheres containing appreciable amounts of oxygen, water vapor or carbon dioxide should be avoided because, in view of the highly reactive nature of the calcined char, such atmospheres may result in deleterious effects on the calcinate.

Where the calcinate is employed in producing massive shapes, it is cooled to a temperature approximately 30 to 60 F., preferably about 50 F., above the softening point (previously described) of the bituminous binder employed in the forming operation and used without appreciable time delay or exposure to air.

When producing calcinates for use as such, the calcinate must be cooled to approximately room temperature for torage or transport unless immediately used in high temperature applications. This calcinate is pyrophoric; hence, if stored, it should be stored in a non-oxidizing atmosphere so that it will not catch fire.

The blending stage In order to produce massive shapes such as briquettes, extrusions, castings, etc., the highly reactive calcinate must be cooled to the proper temperature, 30 to 60 F. above the ASTM ring and ball softening point (100 to 225 F.) of the binder employed.

At this point the calcinate is mixed with the prepared binder, which is introduced at the proper mixing temperature, as heretofore specified, in proportions of from -90% calcinate to 25-10% binder. The percentages are based on the weight of the total These limits are critical, not only from the standpoint of copolymerization and the production of final massive shapes of desired strength, but also from the standpoint that the green shapes must stand mechanical handling. Below the lower limits of this range of ratio of binder to calcinate, the green shapes wfll tend to fall apart as a dry mix. Above the upper limits of this range, the green shapes will soften, sag and agglomerate during curing, with attendant losses and process difiiculties.

The optimum ratio for dry calcinate to binder is determined by laboratory tests to give the strongest product consistent with high yields. If too much binder is used, the unneeded portion will distill out; if too little is used,

the shapes will disintegrate in curing and coking, with attendant high losses due to the production of fines.

It is advantageous to complete blending in the time it takes to actually coat the calcinate particles with a uniform layer of binder; the time during which the mixing or blending is eifected is not critical.

Preferred binders are coal tar pitch or pitches produced by the condensation of tars from the gases evolved during the carbonization and subsequent dehydration and oxidation of the resultant tar to produce pitches having a softening point of from to 225 F. (ASTM ring t: so

and ball as described). High-temperature or low-temperature coal tar pitches are satisfactory.

When mechanical pressure is used to form the shapes, i.e., extrusion or briquetting, from this mixture of calcinate and binder, pressure in excess of 5,000 pounds per square inch is desirable. Below compacting pressures of this magnitude, the shapes will be sandy and tend to fall apart. Below this compacting pressure, the shapes will, on final processing, not meet the requirements for physical strength. The maximum pressure usable and desirable depends on the size of the shapes and the type of equipment used. The higher the pressure, generally speaking, the greater the crushing strength of the final coked shapes.

Forming to shapes can be carried out in any conventional briquetting or pelleting equipment to produce briquettes or pellets of any desired shape. quetting equipment may be molds or rolls in which the mixture is subjected to pressure. Alternatively, extrusion equipment may be used to extrude the mixture in the form of rods of any prescribed cross-section, and the rods may be cut into desired lengths to produce the shapes required. Surface-tension pellotizing equipment can, of course, be used.

The size and form of the shapes will be dictated by the final use to which the shapes are put. For the reduction of phosphorus in conventional arc-type furnaces, the preferred size is a shaped pillow approximately 4" x /Zs x /2. For blast furnaces, the size is approximately 2" x 1''. For cupola-type furnaces, 6 x 4 pillows may be required. I

All of these sizes have been successfully produced by these forming methods.

The curing stage The shapes so formed from this calcinate and binder blend are pyrophoric and unstable and cannot be stored in bulk. They are moved directly to the curing stage wherein the copolymerization is initiated and sustained by subjecting the green shapes to treatment with, or without, heat in an atmosphere containing from 2.5% to 21% oxygen. The composition of this atmosphere may be achieved by use of 100% at low temperatures and low bed heights or by dilution of the air with gases (c.g., carbon monoxide, nitrogen, flue gas containing little or no water vapor, or carbon dioxide) which are inert to the shapes and to the volatile hydrocarbonaceous components of that portion of the binder which is substantially unreacted.

Practically, this copolymerization is achieved at the r maximum reaction temperature consistent with the amount and natureof the binder and yet below the ignition point of the volatile hydrocarbonaceous components of the binder which may exist in combustible concentrations (outside the massive shape). The temperature must not exceed 50 F. below the coking point of the binder as determined in the ASTM distillation by that point at which the coke begins to appear on the side of the distillation flask. Such coking ot the binder must be avoided since that quantity of binder which forms coke during curing reduces, directly, the amount of copoly-znerization of the binder and ca'lcinate. These copolymers form the homogeneous precursors of the chemically uniform, physically strong, coke briquettes.

Curing has been effected at room temperature in 100% an oxygen) by holding the shapes under such conditions for four days with the shapes so distributed that the heat generated is readily dissipated.

Curing is practically and preferably accomplished by subjecting the green shapes to an atmosphere of -21% by volume of oxygen at maximum temperature (450- 500 P.) for 90 to 180 minutes, preferably about 2 hours. The curing conditions that must be maintained for an acceptable product are a function of oxygen concentration in the curing atmosphere, temperature of the curing en- Thus, the hri-.

vironment, thickness or height of the bed of massive shapes, and the rate at which heat is introduced and removed from the bed. Oxygen is needed in this stage as the catalyst or catalytic raw material. If the green shapes are subjected to temperatures above the softening point of the unreacted binder in concentrations of oxygen below 2.5%, disintegration of the shapes takes place at an extremely rapid rate. On the other hand, at temperatures approaching the coking temperature for a given binder and in beds of massive shapes above 24 in height, combustion of the hydrocarbonaceous volatile components of the binder occurs where the oxygen concentration exceeds 4% by volume of the entering curing atmosphere. Hence, under such conditions, the oxygen concentration should be maintained below 4% by volume. With beds of lesser height, the oxygen concentration may be increased accordingly. With beds of 6" or less in height, 20% oxygen (air) maybe used in the curing medium.

It is obvious to one skilled in the art that various combinations of these variable quantities within the limits specified may be successfully employed.

This catalytic etfect of oxygen may be enhanced, if so desired, by the addition of other catalysts during the curing process. Such catalysts may be incorporated in the green shapes before curing. Such incorporation may be made in gaseous, solution or solid form during blending or in gaseous or solution form in the curing atmosphere. Suitable catalysts are boron trifluoride and its complexes, aluminum chloride, hydrogen peroxide, phosphoric acid, etc. The amount of such catalyst employed may be from 0.1% to 5% based on the weight of the shapes. Maximum or near maximum strengths result, for example, with boron trifiuoride complexes and aluminum chloride in about 60 minutes curing time. in the case of hydrogen peroxide or phosphoric acid, minutes curing time gives maximum strength briquettes.

The velocity of the curing atmosphere passing through V The coking stage The cured shapes are subjected to coking at temperatures and times of such magnitude as to insure the reduction'of the volatile combustible content (VCM) to a value below 2% At the same time, this treatment efifects an increase in strength and helps create that degree of reactivity specified for the end product. This is normally accomplished at temperatures above 1500" F. for at least 5 minutes in an atmosphere substantially free of carbon dioxide, water vapor and oxygen. At 1500 F, a minimum time of 15 minutes is required; at 1700 F, a minimum time of '10 minutes is required. At 1500 F. coking can be continued for about one hour without loss of reactivity. At 1700" F. coking can be continued for about 4-0 minutes without loss of reactivity.

The effect of higher temperatures is to increase the strength (resistance to crushing pressures) and decrease the chemical reactivity. These effects are also achieved by increasing the residence timea-t any given temperature.

the calciner may be used for this purpose.

This stage results in coke formation from the co- 7 polymerized binder and calcinate in the cured shape to produce a chemically and physically uniform carbon structure in the final product.

The coking may be effected in a coking kiln, desirably a vertical kiln, into the top of which the cured shapes are introduced and gravitate downward countercurrent to the hot gases. Alternatively, the coking may be effected on a traveling grate passing through a suitable furnace.

The coked briquettes are cooled to a temperature (about 500 F.) at which exposure to air is not detrimental, or to a lower temperature, if desired. Such cooling may be effected by passing cooling gas over or through a bed of coked shapes. This gas must be substantially free of carbon dioxide, water vapor and oxygen. Desirably, it is eflected in the lower portion of the shaft kiln, in the upper portion of which the cured shapes are coked.

The resultant briquettes withstand crushing pressures of at least 3,000 pounds per square inch, remain stable under all operating and storage conditions, are exceptionally resistant to abrasion, and possess other desirable properties; by observing the necessary conditions herein disclosed, briquettes of desired chemical reactivity result, including briquettes which react uniformly and are eminently satisfactory for use in metallurgical furnaces, such as blast and phosphorus furnaces.

Referring now to FIGURE 2, which shows a preferred arrangement of equipment for practicing a process which results in the products of this invention, 1 indicates the pulverized coal feed to a screw conveyor 2 which discharges continuously into the catalyzer 3. The catalyzer contains a fluidized bed 4 of the pulverized coal particles. The fluidized bed 4 is activated by a hot gas stream 5 containing steam and air. The hot gas stream 5 may be controlled to maintain the desired atmosphere in the catalyzer 3. The catalyzer is equipped with an internal cyclone separator 6 through which gases evolved in the catalyzer are discharged through line 7. The cyclone separator 6 also removes entrained coal particles from the gas and returns the particles to the fluidized bed 4.

The catalyzer 3 discharges coal continuously through line 8 into the carbonizer 9. The carbonizer contains a fluidized bed 10 of the catalyzed coal particles. A stream of hot air and inert gas 11 is supplied as the fluidizing medium. The carbonizer 9 is equipped with an internal cyclone separator 12 through which gases evolved in the carbonizer are discharged. A gas take-off line 13 leads from the cyclone separator 12 to the condenser 30 hereinafter described. The cyclone separator 12 also removes char particles from the gas and returns the particles to the fluidized bed 10.

The carbonizer 9 discharges char continuously through line 14 into the calciner 15. The calciner contains a fluidized bed 16 of the char particles. A stream of hot air and inert gas 17 is supplied as the fluidizing medium. The calciner is equipped with an internal cyclone separator 18 through which fuel gas evolved in the calciner 15 is discharged through line 19. The cyclone separator 18 also removes char particles from the fuel gas and returns the particles to the fluidized bed 16.

The calciner 15 discharges calcined char continuously through line 20 into the cooler 21. The cooler contains a fluidized bed 22 of calcined char particles fluidized by a stream of inert gas supplied through line 23. The cooler is equipped with an internal cyclone separator 24 through which gases are discharged through line 25. The cyclone separator also removes char particles from the gas and returns the particles to the fluidized bed 22. The cooler 21 is also equipped with internal cooling coils 26 through which a suitable cooling medium may be circulated. Calcinate is continuously discharged from the cooler 21 through a rotary valve 27, then through a line 28 to the blender 29.

The tar recovery system comprises a condenser 30 supplied with a circulating cooling liquid to condense the tar and a portion of the water vapor in the gas which enters the condenser 30 from line 13. Fuel gas leaves the condenser through line 31. Tarry condensate leaves the condenser 30 through line 32 and is discharged into the decanter 33. Tar from the decanter is pumped through line 34 to the conditioner 35. The conditioner is equipped with an agitator 36. The tar in the conditioner can be heated while being agitated and is air blown by air introduced at 37 to remove moisture and raise the tar softening point. Excess gas is removed through line 38. Tar binder is pumped from the bottom of the conditioner 35 through line 39 to the blender 29.

The blender 29 discharges the calcinate-tar mixture through line 40 into the briquette former 41 which produces briquettes. The briquettes are discharged onto conveyor 42 which communicates with the curing oven 43. A stream of hot gas is recycled through the curing oven by blower 44; this gas is heated in the gas heater 45. The desired oxygen content of the recycle gas is made up by supplying air through line 46. Waste gases evolved in the curing oven are discharged through line 47.

The cured briquettes are discharged continuously from the curing oven 43 into the coker 48. The cured briquettes move slowly through the coker 48 through a flowing stream of inert reducing gas which is continuously removed from the coker by blower 49; the gas thus removed passes through the gas cooler 50. The cooled gas reenters the coker through line 51 near the discharge end to cool the coked briquettes. A portion of the cooled gas passes through a heater 52 and enters the coker through line 53. This gas maintains a high enough temperature to coke the cured briquettes entering the coker 48. Fuel gas evolved in the coker is discharged through line 54. The coked briquettes are discharged into a conveyor 55 and removed to storage.

The following procedures are illustrative of those resulting in the production of the shapes embodying this invention. In all procedures given below, coal was ground in a hammer mill having a ,4 inch mesh screen to produce finely divided coal particles, 100% of which passed a No. 14 Tyler screen size, and of which was retained on a No. 325 Tyler screen size.

The processing of this finely divided coal was carried out in equipment, in general, of the type shown in FIG- URE 2 of the drawings.

Procedures I and II involved sub-bituminous coals identified in Table 3 which follows.

In the tables D.B. means Dry Basis.

TABLE 3 Procedure I Procedure II Specific species Elkol-Adaville D. 0. Clarke No.

Seam. 7 & No. 7%. Kcmmerer, Superior,

Wyoming. Wyoming. Sub-Bitumi- Sub-Bituminous B. nous A. Agglomerating properties Non-agglomer- Non-agglomerating. ating.

GENERAL ANALYSIS Heating value (ash free, gross B.t.u.)

Carbon 70.8 74.9. Hydro en 5.2. 5.7. Oxygen 18.8 15.1. Nitrogen 0.9 1.5. Sulfur 0.8 0.7. Ash- 3.4.-. 2.0.

The conditions of each of the stages or steps are giuen;

in Table 4 which follows: C-atalyzing;.,. v

7 Composition, volu e percent TABLE 4 7 Oxygen 2.0.

g 5 Nitrogen 7.0. Procedure I" Procedure II Steam Carbonizing: V oatiildyzhitlglz f h 6 3 8 Length Of run,'hours 87.

eng 0 run ours A Tom solids red, lbs 54.3 47.9. Total f f f 7,340- gatalyzeli;insidgfldigangttgyglighesn 10 Carbonlzer lIlSlde diameter, lnches 10.02.

em Bra. 1110 0 111 e o r H Resigence time, minutes: 21 3a. arenfpelatulze OI F Fluilizingfi Ine{1iu11n: t c 0 5 Residence time, mlnutes 53.

ll er 0131 V6 001 y, .se v Cogiposition, volume percent: Y Fluldlzmg m u N rygen Superficial veloclty, ft./sec. 0.88.

t31 ?.f:::::::::::::::::: Composition. P carl onizgl gz hows Oxygen 5.0.

a: onizerinsi e iame e!, no es. Temperatureoffiuid bed,'F 76 o gesiglenee timgl minutes 3 0 Calcinlngz Superficial velooity,ft./sec Length f hours V87- Composition, volumepercent: Total 'SOhdS fed, lbS. 4,620.

Calciner inside diameter. inches 12. Temperature of fluid bed, F. 1 490. 081mm Length of run, hours q tune} mlnutes -V-' Total solids r d ibsn nn Flu1d1z1ngmed1ums e I l gil l gga ti ii e' i fli fi d bi d, F Superfic al velocity, ft./sec. 0.54. llifsilenge tlmgifilnmlltes Composltmn, vol. percent:

111 ll me I V V su er ficiai velocity, ft./sec. Oxygen Composition,volumepercent: Nitrogen I 89.0,

Cooling: 1' Coolin r 'T 0 Te nperature of fluid bed, F.-. C i l"? of m "'IT 4 Composition offllidizmg med1- Nllgagyelg. omposition of fluidizing medium,

um, v01. percen Temperature oifiuidiziugmedi- 80. 80. a 7 vol percent T? Ti ""5 Nltr'ogen (100) my a Temperature of fluidizing medium,

Blending: r r F. '80

mm ofbinder Blowntarirom earbomzation f". "f

140 Rsofte nmg point. Blending: V

o a mix. I V V.... W I Anotuntlofcalcinatmwt. percent 82 72.6. carbonizatron,

o ota mix. Temperature of blend, F 160 160. 40 V 7 149 F. ft- Time otblend, minutes 4m V V enmg point.

Forr rli isnlgg Em" in Extrusion Amount of binder, weight percent of Pressure,1bS./i i gg i gg total ImX 18. e g h p gg fl $1 9 X X Amount of calcinate, wt. Percent of 82 uring: 5 0L8. lTllX Bed hei hts, inches V y. a Temper ature of the curing atmos- 4%0zb10 4%0dz10. Tf3mperamre of 'f o F- V160.

phere, Time of blend, minutes 4. Composition of the curing atmos- V phere-vo1. percent: Forming: 7 I

?it.;:::::::::: ype Pillow C kResidence time of shapes, minutes. 0 briquettes.

Be d heights, inehes Pressure, Terlnpera tiire of the coking atmos- SlZe 0f shapes, lnches outside diameter 1' Rgsige l me time, minutes X Inches e v X 3/1 X corlnpositioln of the goking atm V Curing: V g

to n r r p 5;; 1 liedheight, 1nchf'ies. h 84. irogen emperature o t e curing atm=os C k eld t. ercent of coal gleB fl ,W p phe16, F. 45021120.

7 Composition of the curing atmoshere volume ercent PROCEDURE'III g P. 3 5 v This procedure involved the same sub-bituminous coal. In rt's 96.5.

as in Procedure I usinglarger equipment of the same R id e im f Shapes, minutes general type as shown in FIGURE 2. The conditions of C ki Procedure III are given in Table 5 which follows. T B d'h i h i h g' 72.

' TABLE 5 7 Temperature of the cokmg atmosphere, F 1,687. catalyzing: Residence time, minutes 10.

Length of run, hours 87. r p Composition vof the Coking Atmos- Total solids fed, lbs, 8,55 2; 7 phere, volume percent-.- Catalyzer insidediam e ter, inches .]10.02'. t am 18.2.- Temperature of fluid bed, F. 372. Carbon dioxide 4.1.- Residence time, minutes 25. Hydrocarbons 9.5. Fluidizing medium-- g )7 Nitrogen 68.2. Superficial velocity,'ft;/sec. 0.86. Coke yield: :wt. percent of coal, D.B. 58.

' TABLE 5-- Co'ntinuec1 Procedures IV and V involved bituminous coals, identified in Table 6 Which follows and were carried out in the same general type of equipment used in Procedure I:

The conditions of each of the stages or cedures IV and V are given in Table 7 which follows:

TABLE 7 steps of Pro- Proccdure IV Procedure V Catalyzing:

Length of run, hours Total solids fed, lbs Catalyzer inside diameter, inc es. Temperature of fluid bed, F" Residence time, minutes Fluidizing medium:

Superficial velocity, it./sec Composition, volume percent:

Oxygen Nitrogen- Steam Carbonizing:

Length of run, hours Total solids fed, lbs Carhonizer inside diameter, inches. Temperature of fluid bed, F Residence time, minutes Fluidizing medium:

Superficial velocity, it./sec Composition, volume percent:

Oxygen Nitrogen. Steam Calcining:

Length of run, hours Total solids fed, lbs

Calciner inside diameter, inche Temperature of fluid bed, F.

Residence time, minutes 10 Fluidizing medium:

Superficial velocity, ft./sec Composition, volume percent:

Oxygen Nitrogen Cooling:

Temperature of Fluid bed, F Composition of fluidizing medium,

vol. percent. Temperature of iimdizmg medium, F. Blending:

Kind of binder Amount of calcinate, Wt. percent of total mix.

Amount of binder, wt. percent of total mix.

Temperature of blend, F

Time of blend, minutes Pressure, lbs/in. Size of shapes, inches outside 4 diameter x inches high.

urmg:

Bed height, inches Temperature of the curing atmosphere, F. Composition of the curing atmosphere, vol. percent:

Oxygen Inerts Residence time of shapes, minutes.

Nitrogen Blown tar from carbonizationl Nitrogen 140 F. softening point. 80 82.

Extrusion. 20,000. 1.125 x 0.75.

TABLE 7-Continued Procedure IV Procedure V Coking:

Bed height, inches Temperature of the coking atmosphere, F.

Residence time, minutes Composition of the coking atmosphere, vol. percent:

Hydrocarbons 5 Nitrogen Coke yield, wt. percent of coal, D.B

PROCEDURE VI This procedure involved lignite having non-agglomerating properties and of the specific species known as Sandow located at Rockdale, Texas. The analysis of the lignite Was as follows.

Heating value (ash free, gross B.t.u.) 10,757 Moisture, wt. percent 25.2 Volatile matter, wt. percent, dry basis 49.8 Fixed carbon, wt. percent, dry basis 34.8 Ash, wt. percent, dry basis 15.4 Elemental analysis, wt. percent, dry basis:

Carbon 61.3 Hydrogen 4.41 Oxygen 16.98 Nitrogen 1.25 Sulfur 1.99

Ash 14.07

As noted, the lignite was ground in a hammer mill and the finely divided lignite was then processed in the same general type of equipment as in Procedure I. The conditions were as indicated in Table 8, which follows.

TABLE 8 catalyzing:

Length of run, hours 10. Total solids fed, lbs. 54. Catalyzer inside diameter, inches 3.07. Temperature of fluid bed, F. 350. Residence time, minutes 36. Fluidizing medium Superficial velocity, ft./sec. 0.4. Composition, volume percent:

Oxygen 1.2. Nitrogen 36.2. Steam 62.6. Carbonizing:

Length of run, hours 11. Total solids fed, lbs. 33.

Carbonizer inside diameter, inches 3.07. Temperature of fluid bed, F. 950.

Nitrogen 88.9.

2a or TABLE 8-Continued Cooling:

Temperature of fluid bed, F; 150. Composition of fiuidizing medium, 1

vol. percent Nitrogen (100%). Temperature of fluidizing medium," 7 o 80.

Blending: p a Kind of binder Blown tar from a carbonization, 140 F. soft ening point. Amount of binder, wt. percent of V total mix Amount of calcinate, wt. percent of total mix -I. 80. Temperature ofblend, F. i 160.

Time of blend, minutes 10.

Forming:

Type Extrusion.) Pressure, lbs/in. 20,000. Size of shape, inches outside diamev I ter x inches high 1.25 x 0.75. Curing: v Bed height, inches Temperature of curing atmosphere,

*F. 4001 20. Composition of curing atmosphere,

vol. percent-- 7 V 7 Oxygen 21. Inerts 79. Residence time of shapes, minutes 120. Coking:

Bed height, inches Temperature of coking atmosphere,

F. 1700; Residence time, minutes 10. Composition of coking atmosphere,

vol. percent Hydrocarbons 5. Nitrogen 95. Coke yield: wt. percent of coal, D.B. 54.

It will be noted that in the production of the calcined char particles which are mixed'with' the binder and the p amass V resistance to. crushing is at least 3,000 pounds per square inch, three or more times that of by-product coke.

The chemical reactivity of the carbonaceous shapes of the present invention with carbon dioxide under the comparative'test conditions hereinabove given,'is at least five times that of by-product coke, and the reactivity with steam under the comparative test conditions hereinabove set'forth, is about four or more times that of by-product coke; in the case of some of the examples it is more than ten times that of by-product coke. The surface area (BET nitrogen) of the carbonaceous shapes of the present invention is more than'SO'times that of by-product coke. While the real densities of theproducts of the present inventionis of the same order of magnitude as that of by-product coke, the products of the present invention contain a relatively high hydrogen contentwhereas byproduct coke is devoid of hydrogen or may contain small amounts ofghydrogen; the ratio of carbon to hydrogen on a 7 weight basis invariably exceeds200, whereas the products of the'present invention have a ratio within the range of 85 to 110. Taking into account the hydrogen content of the products of the present invention, it is indeed surprising and unexpected that these products have a read density substantially thesame as that ofby-product coke and in some cases even higher real densities. The product of the 7 present invention has a helium density appreciably greater,

. Thin sections of the shapes, examined microscopically,

mixture processed as hereinabove described to produce the shapes, the particles in the catalyzing, carbonizing and calcining stages are exposed to temperatures high.

enough to cause a loss of reactivity only briefly, and'this chiefly in the calcining stage. When these calcinate particles are mixed with the binder, the mixture pressed into shapes, the shapes cured and coked, the carbon formed from the binder has had a temperature treatment not greatly diflerent from the high temperature history of the particles themselves, particularly when the binder used is that derived from the char produced in the carbonizing stage. the carbon from the binder and that from the calcinate particles which are bound together is not essentially different. This explains the homogeneityofthe product and is responsible for its uniform reactivity; both the carbon from the binder and that from the calcinate react at practically the. same rate. Moreover, during the coking of the cured shapes, the binder combines chemically with the original carbon particles resulting in carbons from these two sources which are similar; as noted above, they are not distinguishable under microscopic examination at the magnifications specified. 1

It will be notedv the carbonaceous coke shapes of the present invention have. a physical strength far superior,

Accordingly, the chemical reactivity of show a lace-work of-fine pores, of the order of A of a micron in diameter. The fractured surfaces havea bright metallic luster in contrast to the dull black appearance of carbon particles bound together by amatrix, whereas specimens of formed coke shapes when subjecting to crushing tests, collapse suddenly andform a mass of fines, the carbonaceous shapes ofthis invention crush j to the present disclosure otherwise than as defined by the appended claims.

What is. claimed is:

1. Carbonaceousbriquette constituted of carbonaceous material derived from coal and a tar binder, which carbonaceous briquette is (l) homogeneous, (2) reacts uniformly throughout its mass, (3) has a resistance to crushmg in pounds per square inch determined by measuring the 'gauge reading at which a, 1% x i-nch cylinder crushes under hydraulic pressureapplied to its flat surface of at least 3,000, (4) has a tumbler index value of from to 98, (5) has a volatile combustible material content of below 3% by weight on an ash-free basis, (-6) has a carbon content, on an ash and moisture-free basis of at least by weight, (7) has a surface area of from to 500 square meters per gram, determined by the standard 'the gas absorbed, .(8) has a carbon to hydrogen ratio on a weight basis of from 82 to 114, (9) has a real density of from 1.70 to 2.1 (10.). has a helium density of from 2.3 to 4 and a ratio of helium density to real density within the range of from 1.35 to 2.35, (11) has a reactivity with car-- bon dioxide of at least about 10, measured by the amount of a sample of the briquette sized to pass through a 20- mesh but retained on a 28-mesh screen, consumed in one hour in a stream of carbon dioxide at a temperature of 900 C., passed over the sample at a'rate of 400 ml. per

minute in a tube having an inside diameter of. about 1 inch, and (12) has a reactivity with steam of at least about 20 measured by the amount of a sample of the briquette sized to pass through a 20-mesh but retained on a 28-mesh screen consumed in one hour in a stream of steam at a temperature of 825 C. passed over the sample at a rate of 133 ml. per minute in a tube having an inside diameter of about 1 inch.

2. carbonaceous briquette constituted of carbonaceous material derived from coal and a tar binder, which carbonaceous briquette is homogeneous, contains at least 95% by weight of carbon on a moisture and ash-free basis, has a real density of from 1.70 to 2.1, a ratio of helium density to real density of from 1.35 to 2.35, a carbon to hydrogen ratio on a weight basis of from 82 to 114, and a reactivity with steam of at least 20 measured by the amount of a sample of the briquette sized to pass through a 20-mesh but retained on a 28-rnesh screen consumed in one hour in a stream of steam at a temperature of 825 C. passed over the sample at a rate of 133 ml. per minnute in a tube having an inside diameter of about 1 inch.

3. Carbonaceous briquette constituted of carbonaceous material derived from coal and a tar binder, which carbonaceous briquette is homogeneous, contains at least 95% by weight of carbon on a moisture and ash-free basis, has a real density of from 1.804 to 2.098, has a helium density of from 2.97 to 3.99 and a ratio of helium density to real density of from 1.54 to 2.02, a carbon to hydrogen ratio on a weight basis of from 82 to 114, and

26 a reactivity with steam of at least 20 measured by the amount of a sample of the briquette sized to pass through a 20-mesh but retained on a 28-mesh screen consumed in one hour in a stream of steam at a temperature of 825 C. passed over the sample at a rate of 133 ml. per minute in a tube having an inside diameter of about 1 inch.

References Cited by the Examiner UNITED STATES PATENTS OTHER REFERENCES Desirable Characteristics of Coke, J. D. Davis, from Reports of Investigations, Bureau of Mines, Dept. of Commerce, Serial No. 2,884, July 1928.

DANIEL E. WYMAN, Primary Examiners.

JULIUS GREENWALD, JOSEPH R. LIBERMAN,

ALPHONSO D. SULLIVAN, Examiners.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,184,293 May 18, 1965 Josiah Work et al.

It is hereby certified that error appears in the above numbered pat ent requiring correction and that the said Letters Patent should read as corrected below.

Column 3, line 43, for "explified" read exemplified line 53, for "or" read on, column 7, line 13, for "constituenst" read constituents column 8, line 67, for "disillation" read distillation column 12, line 1, for "a read at line 14, for "partialy" read partially line 23, after "temperatures" insert a period; column 16, line 32, after "with" insert the column 21, line 61, for "carbonizationl" read carbonization column 23, line 24, for "1.25" read 1.125 line 74, for "it" read is column 24, line 23, for "read" read real line 41, for"'flnes"read "fines" Signed and sealed this 7th day of December 1965.

(SEAL) Attest:

ERNEST W. SWIDER EDWARD J. BRENNER Attesting Officer Commissioner of Patents

Claims (1)

1. CARBONACEOUS BRIQUETTE CONSTITUTED OF CARBONACEOUS MATERIAL DERIVED FROM COAL AND A TAR BINDER, WHICH CARBONACEOUS BRIQUETTE IS (1) HOMOGENEOUS, (2) REACTS UNIFORMLY THROUGHOUT ITS MASS, (3) HAS A RESISTANCE TO CRUSHING IN POUNDS PER SQUARE INCH DETERMINED BY MEASURING THE GAUGE READING AT WHICH A 1 1/8 X 3/4 INCH CYLINDER CRUSHES UNDER HYDRAULIC PRESSURE APPLIED TO ITS FLAT SURFACE OF AT LEAST 3,000, (4) HAS A TUMBLER INDES VALUE OF FROM 90 TO 98, (5) HAS A VOLATILE COMBUSTIBLE MATERIAL CONTENT OF BELOW 3% BY WEIGHT ON AN ASH-FREE BASIS,(6) HAS A CARBON CONTENT, ON AN ASH AND MOISTURE-FREE BASIS OF AT LEAST 95% BY WEIGHT, (7) HAS A SURFACE AREA OF FROM 100 TO 500 SQUARE METERS PER GRAM, DETERMINED BY THE STANDARD BRUNAUER, EMMETT AND TELLER METHOD USING NITROGEN AS THE GAS ABSORBED, (8) HAS A CARBON TO HYDROGEN RATIO ON A WEIGHT BASIS OF ROM 8- TO 114, (9) HAS A REAL DENSITY OF FROM 1.70 TO 2.1 (10) HAS A HELIUM DENSITY OF FROM 2.3 TO 4 AND A RATIO OF HELIUM DENSITY TO REAL DENSITY WITHIN THE RANGE OF FROM 1.35 TO 2.35, (11) HAS A REACTIVITY WITH CARBON DIOXIDE OF AT LEAST ABOUT 10, MEASURED BY THE AMOUNT OF A SAMPLE OF THE BRIQUETTE SIZED TO PASS THROUGH A 20MESH BUT RETAINED ON A 28-MESH SCREEN, CONSUMED IN ONE HOUR IN A STREAM OF CARBON DIOXIDE AT A TEMPERATURE OF 900*C., PASSED OVER THE SAMPLE AT A RATE OF 400 ML. PER MINUTE IN A TUBE HAVING AN INSIDE DIAMETER OF ABOUT 1 INCH, AND (12) HAS AREACTIVITY WITH STEAM OF AT LEAST BOUT 20 MEASURED BY THE AMOUNT OF A SAMPLE OF THE BRIQUETTE SIZED TO PASS THROUGH A 20-MESH BUT RETAINED ON A 28-MESH SCREEN CONSUMED IN ONE HOUR IN A STREAM OF STEAM AT A TEMPERATURE OF 825*C. PASSED OVERT THE SAMPLE AT A RATE OF 133 ML. PER MINUTE IN A TUBE HAVING AN INSIDE DIAMETER OF ABOUT 1 INCH.

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