US1675266A - Fuel briquette and method of making same - Google Patents

Description

Patented June 26, 1928.

UNITED- STATES 1, 75,2 6 PATENT OFFICE.

HUGH H. HAN'SARD, OF MONTREAL, QUEBEC, CANADA.

rum. nruevn'r'rn Amp mn'rnon or MAKING sa nt.

No Drawing. Application filed June 23,

This invention relates broadly to fuel briquettes and to the method of making same, and relates more particularly to briquettes made from coal.

An object of the invent-ion is to'provide a briquette which will burn with little or no smoke and without disintegration or adhering to adjoining briquettes, and which will further be sufficiently porous to ignite readily and burn at a desirable rate.

Another object is to provide a briquette sufiiciently hard to withstand transportation and much handling, and also exposure to weather without appreciable disintegration and without undue absorption of moisture.

Still another object is to provide a. briquette having an ash content as low as possibleand in the case of briquettes made from coal with a clinkering tendency, a substantial freedom fromclinkering.

A further object is to provide a process of manufacturing briqiiettes which will enable fulfilment of the foregoing objects.

Still another object is to provide a processof manufacturing briquettes which may be carried out inexpensively and economically.

An additional object is to provide a process which, with suitable variations, is applicable-to the briquetting of any grade of coal, and particularly to certain grades of coal which are not generally available for fuel purposes, to produce therefrom high grades of coal.

ggrade fuel briquettes capable of replacing any of the grades of coal ordinarily used Various other objects and advantages may be ascertained from the following description.

The problem of briquetting materials, particularly coal, for use as fuel is one which has received a great deal of attention in recent years. Rapidly approaching exhaustion of the higher grades of coal makes it necessary. to devise means for employing the lower grades of coal and at thesame time with efiiciency equal to or greater than that obtained with the higher grades, so as to enable the lower grades of coal 'to be used under the conditions which have led to and arisen from the extensive use of the higher The principal difference between the 'various grades of coal is a matter of car-j bonization and accompanying this is the question of ash content. Goals, such as an- 1924. Serial No. 721,939.

thracite, are highly carbonized and contain only a small percentage of volatiles so that they are clean to handle and burn practically smokelessly, making them particularly fitted for domestic use and for commercial sion of much smoke so that they are unsuitable for domestic and for many commercial purposes. Still other grades of coal, commonly included under the term lignites, are but little carbonized and contain a relatively large percentage of volatiles, also con siderable moisture, so that they are unsuitable for most commercial uses unless burned in specially constructed furnaces orsu'bjected to special treatment to overcome or offset their inherent disadvantages.

' The general method of briquetting coal is to incorporate the pulverized coal with a hydrocarbon binder, such as pitch or asphalt, and then to press the mixture into briquettes. Experience has shown that hydrocarbon binders which mix readily with the powdered coal produce briquettes which are comparatively soft and in which the binder has a low melting point, so that the briquette d isintegrates with transportation or handling and also during combustion with the additional disadvantage of adhering to adjoining briquettes. High melting point binders are difiicult to incorporate with the powdered coal and as a result an unduly large proportion of binder must be used, The briquettes, while hard; enough to withstand transportation and handling and to avoid disintegra- 1 tion during combustion, are so dense as to be diflicult to ignite and slow burning. Also the expense of their production is so great as to seriously limit their use.

According to the present invention a briquette may be produced having requisite hardness to avoid disintegration in handling or combustion and which further will not adhere to adjoining briquettes when heated.

Such a 'briquette may be made inexpensively from any grade of coal and if desired the. ash content and clinkering elements of the coal may be wholly or largely removed, also the degree of carbonization may be" increased and thedensity varied as necesary to obtain any desired speed of ignitionor combustlon.

The binder as it appears in the finished briquette has a high melting point and moreover is very intimately associated with the particles of coal and in amount suflicient,

' cost of briquetting. v i

' and also the low boiling portions of the.

of the v0 The process of briquetti ng briefly described is as follows: Coal is very finely ground or otherwise ulverized so as to pass through, for exam e, a 200-mesh screen,

although the particles ofcoal may be either larger or smaller than thus indicated. This pu verized coal if of a quality suitable for immediate briquetting is then mixed'with a predetermined amount of a liquid hydrocaron binder, such'as crude oil, preferably that having an asphalt base, or with coal tar or any other suitable hydrocarbon binder. An

intimate and thorou h mixing of -the coal and binder is enable by the use of a binder suitably fluid in. its natural state or rendered suitably fluid by the addition of diluents. The mixing is, effected in any well known manner,'as by means of a ball mill, and continued until, as nearly as commer cially possible,'every particle of the pulver! ized coal has received a film or coating of the binding materiaL. The mixture is then heated withexclnsion of air to drive ofi the volatiles of the binder and the coal itself binder, with the result that there remains a mass of coal particles each-having a very material. The amount of binding material ori inally mixed with the coal is gauged acterial and the temperature at which it will be heated, WhlCh temperature is determined partly by the nature of the coal, so that after the heating a predetermined percentage of terial in excess of that actually required for b nding purposes may be avoided.- The heat treatment also serves-to effect a carbonizing action in the coal. heat treatment the pressed in-any suitable way into briquettes, which arethen ready'for use or which may be sultabl aged or cured by, retention in storage wingto the evaporation of the low boilinfg constituents of the binder and atiles of the coalv and binder, it Wlll be readily seen that as only the high After completion of the I boiling constituents remain, requisite hard.-v

ness'to withstand disintegration during handlmg and combustion will result. The physibonizatiomof the coal as well as expulsion of volatiles will enable coal, such as-bitum'inous coal or lignites, to be converted-into j briquettes having the 'combustlon characters coated coal particles are cal hardness ofthebriquette and the porosity thereof depend of course to a considerablev therefore more readily combustible than is ordinarily the case owing to the use of the minimum amount of binder which does not I fill the tiny voids between the particles of coal. The volatiles and low boiling material a driven off during the heattreatment may be recoveredand their value will largely coma:

pensate for, or even more than compensate for, the entire cost of treatment and briquetting of the coal, so that briquettesof superior quality may be sold at. comparatively low prices. The heating step which causes caristics of anthracite coal or anthracite I briquettes. v y s f Where the coal dealt with has an undesir-' able high ash content the-grinding may be sufiiciently fine to effect an appreciable or I substantially complete mechanical separation of the carbonaceous particles and the ash,- particles. This powder may then be wet with water and subsequently mixed with'th'e oily binding material. The oily hydrocar- I Patent 1922.. v

' t has furthennorelbeendiscoveredthe whenfdealing with coals'containing a sum cient percentagei of' readily separable bitu bon binder has greater afiinity for, the car-12 J bon particles than iorthe ash particles with.

the result that .an effective separation oiv carbon and ash may b'e'efiected to eliminate;

; the ash as fully-describedyin United States ire-. 1,420,165, granted-the 20th June,

y men no additional binder. is requiredbutficor ing to-the natureof the binding mamerely'the addition of a diluent to co-elk."

erate with the heat'treatment in extracting 'the bitumen from the coal, Durin the heat treatment and by meansof an oi y diluent -or solvent, --b itumen is extracted from the coal and serves'asa binder, In. such a case substantially allthe solvent or diluent may.

be distilled MI and in addition a considerable amount of volatiles contained in the coal. Also, when dealing with coals having available binding'material less than required forbriquetting purposes, only that amount of n'eedbe added. v I

The heat treatment may be eifected in anysuitable furnace or retort, preferably "one provided with means forrabbling the mixture and composed of iron or other material binder necessary to make upthe deficiency having a catalytic action in the distillation of volatiles from the binder and coal. The

retort used is referably one of considerable length in whic the material. may pass slowlyfrom a cool zone with gradually increasing temperature to ahot zone at the discharge end.

In order that a better understanding of the invention may be obtained, the following specific example is given. but it -will be understood that the invention-is in no way limited to the details of this example.

Ewqmple I The materials used arecoal analyzing approximately z I "Percent. Moisture 0.80 Volatile "26.00 Fixed carbon 52.00 Ash I 20.00 Sulphur; 1.20

der 650 F.

- coalhas acquired a coating or enveloping film of oil. The mixture is then transferred to a suitable 'retortffor example, such as made by The-American Continuous Retort Company for treatment of oil shales. The mixture is passed through the retort, the temperature of which gradually increases to approximately 650 F. at the dischargeend. During this retorting-volatiles are driven ofi and maybe collected. These volatiles represent about half the weight of the oil and about 4 parts'by weight of the coal. Starting with'12 parts of oil and 98 parts of coal by weight the mixture discharged from the retort will have a composition of 6 parts ofbinding material having a distillation temperature of 650 F..or over, and 94 parts of coal.- The mixture .is then briquetted in any suitable press and the resulting briquette when completely cooledwill-be found sufiiciently hard to stand transportation and handling without disintegration, Owing to" the distribution of the binder through'the pulverized coal when in fluid condition and the subsequent abstraction of" volatiles-there is ft: on each particle of coal a thin teating of binder sufficient tocaus'e the particles to adhere. when pressed and yet not sufiicient to close the voids between particles. The

briquette, while sufliciently tough to-withstand transportation and handling, also possesses the porosity necessary for satisfactory combustion and to avoid-disintegrationof the br1quette by gases generated within the same. The binder in a freshly made briquette has a melting point of 300 F. to 375 F. or over and with ageing this melting point gradually rises. When the briquettes are placed in a fire the first effect of heat is to.further raise the melting point of the binder and drive off as gas some of the constituents. The porous nature of the bri quette permits the escape of these gases without disintegration of the briquette and the unburned binder becomes more and more carbonized. The driving ofi of volatiles during the manufacture 'of the briquette removes a large part of the constituents of both the binder and the coal which cause smoking This. efiect is further increased by the carbonization which takes'place, with the result that the briquettes produced will burn with little or nosmoke and are comparable in this respect and also in their speed of burning with anthracite coal. Y

If the 'pulverized coal is mixed with water before addition of the oil it will be found that the oil, which has a greater aflinity for the carbon particles than for the ash particles, will adhere to the carbon particles to a greater extent than to the ash particles.

with the result that the ash or non-carbon particles may be washed out. Using coal of the analysis given and thus purified a fresh- {y made briquette will analyze approximate-' 37 a 7 Moisture .nil" Volatile 26% Fixed carbon"); 73% Sulphur 1% Ash, trace up to B. t. u 14,500 to 15,500

It will be understood that it is'impossible to lay down any proportion of liquid binding material and coal, as the proportion depends upon the nature of the coal and .par-. I ticularly upon the amount of volatiles and the amount of available binding material in the coal, also upon the amountmf ash and Whether the same is to be removedor not.

It'ma-y .be stated, however. that in the finished briquette there should be from 6 to 10 parts by weightof binder having a melting point of 300 F. or over and serving to agglomerate '94 to 90 parts of coal. It will also be obvious that the proportion of oil mixed with thecoal will, to some extent, be governed by the nature of-the oil and its distill'ation gas been previously stated that v coals andlignites will be carbonized, it must be understood that this does not refer.- to complete carbonization such as would render the material incapable of combustion under ordinary conditions, but

merely to an increased degree of carbonization. It has also been stated that with certain grades of coal containing a comparatively large amount off'soluble materialca lliO 1 tion stepregardless of whether the liquid added is purely a solvent or is-diluted with binding material. Therefore,the amount of liquid binding material used may be varied according to the'nature of the coal. On the other hand where the coal will provide sufiicient binding material the solvent liquid added may be in itself incapable of actin as a hinder or of'being resolved into a bin ing material. It will therefore be understood that the invention is not confined to the addition of the amounts of binding material stated to be found in the completed bri uette, nor to any particular temperature or duration of distillation treatment, or to carbonization or any particular degree of carbonization of the carbonaceous matter but relates to any means by which a small amount of high melting binding material may be intimately incorporated with ca rbonaceous material, the iimount of such binder being usually less than could .be mechanically incorporated to produce a satisfactory coating of the carbonaceous particles without the presence of suflicient binder to fill the interstices of the finished briquette.

While in the foregoing example the melting temperature of the blnder has been given as 300 to 375 F. and the distillation temperature thereofas 650 F. or higher, it must be understood that the invention 'is not limited to these temperatures as satisfactor briquettes may be made using binders which;

melt considerably below 300 F. and which distil considerably below 650 F. Further, the invention, as regards the manner of incorporating the binder and coal, is notsubject to any item erature limitations except those of practice ility.

Instead of immediately briquetting the mixture of binder and finely pulverized coal, this mixture may be itself used as a binding material for a further amount of coal;

When operating in this manner it is preferable to increase the proportion of binding 1 material tothefinely pulverized coal, and to have the additional coal in relativel coarse particles. The following example w'i I serve to illustrate.

.Emwmple'lb A'mixture of pulverized coal, 200-mesh or finer, containing after retorting 82 coal and Il binder, by weight, is mixed with fromtwage to four times its weight of granulated coal which will pass through, say, a

2071118511 screen. thorough mixing the:

mass is briquetted without further retorting.

The resulting briquette is of good quality] and may be roduced more cheaply than'one made entirey -from finely pulverized coal and containsa very low percentage of binding material without appreciable sacrifice of the desirable qualities heretofore enumerated. In vfact, such a briquette is more porous and therefor'e burns more rapidly than one made of finely pulverized coal.

As a variation, the mixture of finely pulverized coal andoil may be combined'with' the coarser coal. before retorting. Also, if s it is desired to omit the retorti-ng ste altogather this manner of mixing may e resorted toifo'rthe purpose of obtaining a" uniform 'andintimate mixture of coal and a relatively very small amount of binder. It

will be understood that the invention is not limited to the proportions of the binder and finely pulverized coal used to make what may 7 a liquid hydrocarbon, heating the mixture 5 to drive ofi. the volatile and low boiling constituents of the liquid hydrocarbon, and briquetting the resulting mass which consists of pulverized coal and the high boiling residueof the liquid hydrocarbon.

2. A process of 'making' fuel bri uettes which consists in mixing pulveriz with a liquid hydrocarbon, heating the'mix tur'e to drive off those constituents thereof,

which distil at 650 F. or under, and bri- 'quetting the remaining mass.

3. A process of making fuel bri uettes which consists in mixing pulveriz coal and liquid hydrocarbon inproportion to produce eventually from 6% to 10% by 11110 melting point of 300 F.- or over, heatin the mixture to separate constituents whic distil ofi below 650 F., and briquetting the weight of hydrocarbon binder having a resulting mass. v 4. A process of making fuel bri uette's;

which comprises coating particles 0 pverized coa with a very thinlayer of high melting hydrocarbon binder by first coating the particles with the binding material in solution and then heat-in" the coated particles to .drive off the so vent, and

finally: 'briquetting' the coated particles.

5. A processof making fuel briquettes which comprisesmix ing the finely powdered coal with a liq'uid'hydrocarbon bindingnia- .terial,heating the-mixture to driveofi vola- I tiles and low boiling constituents of the bindin'g material and to leave as a thin coating on the individual particles of coal a residue having a high melting point, the

- than the least amount of binder of the same melting point that could be directly coated on the particles, and briquetting the coated particles.

6. A process of making fuel briquettes which comprises pulverizing coal to suchdegree of fineness that a substantial mechanical separation of carbonaceous and non-carbonaceous particles is effected, mixing the powder with water, treating the wet mass with a liquid hydrocarbon binding material which, by its greater aifinity for the carbonaceous particles than for the non-car-- bonaceous particles, will effect a separation of the particles in water, washing out the non-car onaceous particles, dryin the mass and heating the sameto distil 0 volatiles and low boiling constituents of. the binder and coal, and briquetting the resulting mass.

7. A process of making fuel briquettes which comprises pulverizing coal to such degree offineness'aswill effect substantial mechanical separation of carbonaceous and non-carbonaceous particles, separately collecting the carbonaceous and non-carbonaceous particles by flotation employing a liquid hydrocarbon oil, distilling the carbonaceous particles and oil together't separate thereom volatile and low boiling constituents, and briquettin the carbonaceous matter .and remaining igh boiling constituents of partic the 011.

8. A process of making fuel briquettes which comprises mixingpulverized coal and a liquid hydrocarbon blndin material, and forming an adhesivefilm 0%high melting binding material on the coal particles by heating the mixture to drive off volatiles and low boiling constituents thereof, and finally briquetting the resulting mass. 9. A process of making fuel briquettesq which comprises mixing dpulverized carbonaceous matter and a liqui hydrocarbon binding material, carbonizing the carbonaceous mass and simultaneously forming a film of high melting binder on the individual es thereof by distilling ofi Volatiles and low boiling constituents, and finally briquetting the mass.

10. In p process of making fuel briquettes the step of carbonizing pulverized carbonaceous matter in resence of a liquid hydrocarbon prior to riquetting with conse uent converslon of the liquid to a high me ting bindin materiah r 11. process of making a hard, substantially smokelessly burning fuel briquette from bituminous, coal or lignite, which comprises distilling pulverized coal or lignite' with a'liquid hydrocarbon at such temperature that the coal or lignite is materially carbonized and the. liquid'h drocarbon reduced to a high melting bin ing agent distributed as l-thin film on the particles of carbonized material, and finally briquetting the mass.

12. A process of making hard, free and smokelessly burning, porous fuel briquettes which comprises incorporating w th p1 '1l-. verizedcoal a hydrocarbon binding material in fluid form, distilling the mixture for removal of volatiles and low boiling material from the coal and binding fluid and for the production of a thin'film of high meltmg binder on the coal particles and for the carbonization of coal particles, and finally briquetting the resulting mass under pressure sufficient to cause adhesion of the coated particles in-a porous structure. 13. A process of making fuel briquettes which comprises mixing with pulverized coal at liquid hydrocarbon incapable in itself of forming a binder or of being converted to a satisfactorybinding agent butcapable with heating of dissolving out of the coal ,material to form a binding agent, heating the mixture to dissolve out the binding material and subsequently to distil ofl the solvent, and briquetting the resulting 'mass.

ing binder disposed ,in a film on the particlessofcarbonaceous' matter and in amount less than could be incorporated by mechanical means to coat substantlally all the particles.

16. A fuel briquette composed of pulveru- I lent particles of carbonaceous matter and a small amount of high melting hydrocarbon binding material disposed in thin films upon the particles and serving tofbind the particles together into a hard, porous mass capableof burning freely and substantially smokelessly and without crumbling or adhering to adjoining briquettes.

17. A fuel briquette comprising by weight 90 to 94 parts or pulverized carbonaceous matter and 10 to 6 parts of high melting hydrocarbon binder disposed in thin films upon substantially all the particles and binding them together in a porous mass.

18. A fuel briquette composed of powdered coal, the particles of which are coated with a high meltinghydrocarbon binder,

and materially larger particles of coal cemented together by the binder covered particles of coal, the said briquette presenting a multitude of small unobstructed voids for escape of gas generated in combustion and being sufficiently hard and tou h to avoid disintegration in handling and urning.

19. A briquette of the character described in claim 18, in which the. binding material naceous. matter in the form of is formed of volatiles exuded from the coal by distillation and remaining on the sur-- face thereof.

20, A fuel briquette composedof ulverized carbonaceous material and a ydrocarbon binder having a melting oint of 300 F. or over adhering intimate y to the particles in a film so thin as to leave interstices between the particles substantially unobstructed.

21. A fuel briquettecomposed of carboarticles which will pass through a 200-mes screen and a high melting hydrocarbon binder in amount msufli'cient to obstruct interstices between the particles, the said briquette being sufliciently hard and tough to withstand transportation.

22. A fuel briquette capable of burning substantially smokelessly and without 1 crumbling, said briqpette being formed from bituminous coal or ignite and a liquid hydrocarbon, the said briquette being comconstituents and briquetting the mass.

i ativel bon binding-material with a.-relatively large 24. A process of' making fuel bri uettes which consists in mixing pulverize coal and a liquid hydrocarbon, heating the mixture to drive off volatile and low boilingconstituents, mixing the residue with granulated coal and briquetting the mass. 1

25. A process of making fuel bri uettes which consistsv in .mixing pulverize coal and aliquid hydrocarbon to produce a bind- .ing 'material, mixing the binding material with granulated coal, heating the final mixture to drive off volatile and-low boiling '26. A method. of uniformly mixing a, relsmall amount of liquid hydrocaramount ofcoal consists ig iimixing the liquid inder -"v'v1th a portion 0 the coal in 'finelypulverized state, and then mixing the mixture of finely pulverized coal and binder with the remainder of the coal in granular state.

27. A process for making fuel-briquettes,

which comprises heatin finely divided carbonaceous material, suc

tiles therefrom v and until volatiles as bituminous coal or lignite, for expulsion of low boillng1 volaavmg 28. A process of making fuel briquettes which comprises compressing masses of finely divided carbonaceous matter, such as bituminous coal or lignite, the individual gfill'lticles of which are coated with a thin of bind ter' expelled prior to compression, the said film serving to bind-the particles together after compression ina hard rous mass.

29. A process 0 making "fuel briquettes, which comprises heatin finely divided carbonaceous material, suc as bituminous coal or lignite, for expulsion of low bo' volatiles therefrom and until volatiles 'aving melting points of approximately 3009 F. appear at the surface of the particles, intimately mixing the mass with less finely divided particles of carbonaceous material .such as anthracite coal, and briquetting the mixture. a a

30. Mixing together finely divided carbonaceous matter such as anthracite or bitumi-' nous coal or lignite and hydrocarbon oil, distilling themixture and collecting volatiles which come off up, to approximately 650 material be' volatile mat- Fahreiiheit, and retaining the residual solid mass for. use as fuel.

31. Mixing together finely divided carbonaceous matter such as bituminous coal or lignite and a hydrocarbon oil such as crude petroleum, distillin' the mixture at a temperature of 650 ahrenheit and upwards, and collecting the volatiles obtained from the distillation.

'32. A process of preparing hi h-volatile carbonaceous material such as ituminous coal and lignite for use as fuel'and. obtaining volatile constituents therefrom, which comprises extracting a portion of the lower boiling volatiles from the coal by mixin "the carbonaceous material in finely divided 0m with a hydrocarbon oil such as crude petro-v leum, and distillin the mixture.

T33. A coals an lignites for the reparation f smokeless fuel therefrom, which 'compr' distilling the coal or lignite in finel' divided state; and in admixture with a by rocarbon oil for the removal of the lower boiling vola-v tiles thereof, and, separately collecting. the

solid residue and the expelled volatiles.

34. 'A briquette of the character'described om the partic es themselves rocess o treating high volatile in claim .18, in which the binding material is composed in part of volatiles exuded from:

the coal; by distillation and remaining upon the surface thereof and in part ofv the residue of a liquid hydrocarbon binding matei I rial distill .35. A fuel briquette comprising particles of powdered coal coated with a thin film of with the coal, Y

high melting hydrocarbon binder admixed particles, being volatile matter exuded from with and cementing together uncoated coal the coal in distillation and remaining upon particles, the said briquette being hard, the surface thereof. tough and porous. In witness whereof, I have hereunto set 5 36. A fuel briquette composed of distilled my hand.

and undistilled coal particles and a binding material upon the surface of the distilled HUGH H. HANSARD.