US1551966A - Process of preparing materials for briquetting and the product thereof - Google Patents

Description

Sept. 1, 1925. 1,551,966

P C. MULLIGAN ET AL PROCESS OF PREPARING MATERIALS FOR BRIQUETTING AND THE PRODUCT THEREOF Filed Nov. 14, 5

gwue'n tow Mvd elk-bounty!) Patented Sept. 1, 1925.

UNITED STATES 1,551,966 PATENT OFFICE.

PAUL C. MULLIGAN AND HERBERT G. SWALWELL, SEATTLE, WASHINGTON, AS-

SIGNORS TO THEMSELVES, LUTHER J. HULL, AND ISAAC M. FOSTER, ALL OF SE- ATTLE, WASHINGTQN.

PROCESS OF PREPARING MATERIALS FOR BRIQUETTTNG AND THE PRODUCT THEREOF,

Application filed November 14, 1923. Serial No. 674,704.

To all whom it may concern:

Be it known that we, PAUL C. MULLIGAN and HERBERT G. SWALWELL, citizens of the United States of America, and residents of the city of Seattle, in the county of King and State of Washington, have invented certain new and useful Improvements in Processes of Preparing Materials for Briquetting and the Product Thereof, of which the following is a specification.

Our invention relates to the art of briquetting, and particularly to the preparation of materials for briquetting.

Our invention is more especially designed *7 for the utilization of waste products such as saw dust or wood chips, and will be described with particular relation thereto. However, in the following specification and in the claims terminating the same, it will be understood that the term granular material is intended to apply either to saw dust or to wood chips in the natural state, or dried or charred, and either separated or in combination, or to other combustible matter in a divided form, which it is desired to finally compress into the form of a briquet.

One of our principal objects is the provision of a process whereby such granular materials may be prepared for briquetting through the use of a solid binder which may be supplied in a pulverized form and without heating, rather than in a liquid form, as has been customary heretofore, rendering it possible to employ an air current for handling this pulverized binder, and making it possible also to employ a simple beater type of pulverizer for the pulverizatio-n of such solid binder Without danger of fouling the screens employed in such a pulverizer.

A further object is the provision of a process for the preparation of materials for briquetting, whereby the fuel value and the amount of flame-producing volatiles in the final briquet may be increased by the addition thereto of a liquid hydrocarbon, as fuel oil, in such a manner that it will remain in the briquet and will not exude theligfrom or render the briquet moist or stic A further object is the provision af a process for preparing materials for briquetting, which may be carried on continuously,

without interruption, to the end that the dentally with the present application, yet it will be understood that the use of this particular piece of apparatus is not essential to the process, nor in fact, is it essentialthat any particular form of apparatus be employed in carrying out the same. The apparatus which we have illustrated diagrammatically in the accompanying drawings represents only a form which might conveniently be employed in carrying out the process.

Our invention comprises the novel steps, combinations and arrangements thereof in the process of preparing materials for briquetting, and in the novel mixture for briquetting and the novel briquet formed from such mixture, all as disclosed in this specification and in the claims terminating the same.

I Figure 1 represents diagrammatically a complete plant for the carrying out of our process of briquetting.

Figure 2 represents a transverse section through a beater type of pulverizer, illustrating a form which may conveniently be employed in carrying out our process, al.

though it will be understood that the use of this particular type of apparatus is not essential.

As we have stated above the base material which is in granular form, will preferably be carbonized wood saw-dust or chips. The saw-dust is generally considered a Waste product and it is to utilize this waste that our process is particularly intended.- It should be understood, however, that we do not consider thatour process is limited only to the utilization of such materials, and in fact, .we have found it adaptable to the briquetting of such materials as .ordmary ground charcoal or coal. Also wemay wish to utilize other combustible materlals which are ordinarily wasted, and for that reason have chosen the term granular material, as representing a material or several materials in granular form, generally of vegetable origin, and combustible, which it is desired to incorporate into a briquet as the base thereof. a

The material, if saw-dust or chlps or like material is used, is. first dried. We have shown in the drawings no means of drying the granular material, nor in fact, do we consider this strictly a part of our process, but merely a preliminary step which must be taken if the material requires it. Preferably the material is dried to the point of charring. After drying the material may be stored in a convenient place, as in a storage bin 1, from which it is fed as required into the hopper 20 of a mixing chamber 2. As it enters the chamber 2 a liquid hydrocarbon, as, for example, fuel oil,- may be sup-' plied thereto. The oil is supplied for the purpose of adding volatile matter to the briquet, and its use for some briquets may be dispensed with, although preferably it is employed.

The oil we have shown as being supplied from a tank 3 by means of a conduit 30, and we have shown a conduit for air which is contained in a holder 4 under pressure, which also communicates at 31 to a spray nozzle with which the oil conduit 30 is connected. By this means .the oil, the supply of which may be controlled, as by a valve 82,

is sprayed into and upon the granular material as it enters the mixing chamber 2. The oil and dry granular material are suitably mixed, as by a screw 21 within the chamber '2, and finally when the mixing has progressed sufficiently that the oil impregnates the dry granular material, the oil-moistened granular material is delivered to a second mixing chamber 5.

During the time that the oil and granular material are being mixed, a binder therefor, which preferably consists, simply of normally solid asphalt, isbeing prepared for mixture therewith. In the drawings 60 represents the casing of a common beater type pulverizer. In such apulverizer, beaters 6 of hard metal are pivoted upon the ends of arms 61, which in turn arepivoted upon a rotatable hub 62. Material to be pulverized is fed into a hopper 63 atthe top of the casing 60 and as the beaters 6 rotate close to the interior of the casing 60, the solid materials are pulverized and finally dropped through a screen 64 forming the bottom ofthrough aseparator 68 with the'chamber 5.

The pulverized asphalt enters the chamber 5 at substantially the same point as the oilmoistened granular material, and preferably is carried thence by an air current from the blower 66. The pulverized material is deposited upon the moist granular material and the air which serves as a vehicle therefor 'passes through the chamber 5, which should be closed, and during its passage the air is relieved of all of the pulverized material. It is permitted to escape through a screened opening 50.

'lVithin the chamber 5 the pulverized binder and the g anular base are thoroughly mixed to disseminate the binder throughout the mixture. This may be done by means of a second screw conveyor 51 within the chamber 5. I The material is then ready for briquetting and may be delivered from the chamber 5 continuously into a hopper 7 3 of a briquetting press, indicated in general by the numeral 7 which, operating continuously, will produce briquets from the material thus prepared. For. convenience we have shown the briquetting press 7 as containing a cylinder 7 0 in which, by means of a piston, not shown, it is possible to compress air to be delivered through a conduit 74 to the air storage tank 4.

It has heretofore been considered impossible to use asphalt as a binder for briquetting in the solid form, and without heating. This has been for the reason that the asphalt has always tended to clog the screens of pulverizers employed to reduce it to a powdered form. We have discovered, however, that by means of the addition to the pulverizer 60 of a more friable material as, for instance, charcoal or coal, in about the same or slightly greater amounts by weight than the asphalt, but perhaps twice the bulk thereof, it is possible to pulverize the asphalt and the friable material in conjunction with each other, and thereby to render the particles of asphalt so much less sticky than they normally would be that there will be no tendency to clog the screens, as 64. The action appears to be that the friable material, being most readily brokenup, has a portion pulverized first, before any pulverization of the asphalt begins. The particles of the friable material, then act to coat the asphalt and to coatthe particles thereof as formed in such manner that the stickiness of the asphalt is removed, or the asphalt particles are enclosed within a casing of fine particles of the friable material and thus do not cohere into a mass nor adhere to the screen surface. This renders it possible to use this simple and convenient type of pulverizer as described and renders it possible also to convey the pulverized material by means of an any tendency for the asphalt to stick in any part of the apparatus employed.

A number of different materials may be used to prevent stickiness of. the asphalt binder. We have mentioned coal and charcoal as being suitable for such use, and prefer to use them for the reason that these materials are combustible as is the asphalt,

thus rendering the entire briquet combustible. It should be understood, however, that we do not limit ourselves strictly to the use of these two materials as a vehicle or separator for the asphalt particles, but prefer them on account of their combustibility. When other materials are thus employed, the amount employed is determined chiefly by their bulk, sufficient friable material being used to properly coat and separate the binder and its particles in the manner described above.

As a substitute for asphalt we have used other solid binder materials, for example, pitch, both coal tar pitch and resins. We do not wish to be limited, therefore, solely to the use of asphalt as a binder. When pitch is employed, it is still desirable to employ charcoal or the like as a separating medium for the individual particles of the binder material, andto pulverize the charcoal and binder materials together. The charcoal, in this capacity, acts to separate the individual binder particles, to permit handling and to prevent reaccumulatlon thereof.

In brief, then, the complete process consists of the im regnation of the granular base with a liquid hydrocarbon, coincidentally with which impregnation there is a pulverization of the asphalt and of charcoal .to form a combustible carbon carrier or separator therefor, followin which the pulverized materials and the oil-moistened granular materials are mixed thoroughly. The final mixture is then ready to be supplied to a suitable press and upon compression a briquet is formed, which is dr not sticky, which is fairly hard, and whic will not break down while burning.

In compressing the briquetting mixture which we have described, the increased density caused by compression appears to be suflicientto bring the particles of the sticky asphalt binder closely enough together to cause cohesion ofall the granular particles, and as well, of the. pulverized carbon which has been put into the mixture with the pulverized asphalt.

It is difficult to express the proportions of the ingredients in such .a mixture and in the briquet formed therefrom, with any exactness, for the reason that these percentages will vary considerably under varying conditions. For example, the amount of fuel oil will be determined principally by the absorption of the granular base and this in turn will vary with the character of the granular material, whether coal, charcoal or wood, and with the dryness thereof. Gen- "erally speaking, we may employ from 2% to 30% of fuel oil or its equivalent, although generallyin the neighborhood of 16% or' 17 is most desirable. Of the asphalt hinder, the amount will vary with the pressure employed in the briquetting press, and also it will depend to some extent on the amount of fuel oil employed, a greater amount of fuel oil tending to keep the granules of the base material separate and requiring a slightly greater amount of binder. Generally speaking, from 7% to 15% of the asphalt binder will be employed under different conditions, with the preferred amount about 11%, when using carbonized saw-dust and fuel oil as the other constituents. The remainder (with the exception of the amount of carbon which is added with the pulverized asphalt, the per-- centage of this being substantially the same as of asphalt) will be the ranular base. This, as stated above, might be charcoal or coal or such material in combination with saw-dust or wood chips. Granular charcoal, including that introduced into the mixture with the asphalt, may be empolyed in an amount .necessary tocomplete the mixture, and preferablyshould be present in an amount approximatel 73% of the weight moistened base, and finally mixing them to disseminate the binder throughout the mixture.

2. A continuous process of preparing fuels for briquetting which consists in pulverizing an asphalt binder in conjunction with carbon, at the same time impregnating charcoal with fuel oil, introducing the pulverized materials by an air current to the oiled charcoal, whereby the pulverized material is deposited, and then mixing the pulverized material and charcoal to disseminate the former throughout the mixture, i

3. A continuous process for the formation of a fuel briquet which consists in pulverizing a combustible binder in the cold state, in mixing a granular base material with said pulverized binder to disseminate the binder throughout the mixture, and finally com.- pressing it while cold to cause adhesion of the particles.

4. The process of pre aring fuels for briquetting with a norma y solid binder material which consists in pulverizing the binder material in conjunction with carbon, in delivering the pulverized materials to a granular base by means of an air current, the granular base having been moistened by oil just cold and in its normal solid state, together with a more friable material, mixing the pulverized materials with a briquet base, and

compressing the mixture while cold to cause the particles to cohere.

6. A briquetting mixture comprising a granular combustible base impregnated with oil, and a combustible binder in pulverized form thoroughly mixed therewith.

7 A briquetting mixture comprising a granular combustible base impregnated with a li uid hydrocarbon, and a pulverized combustlble binder commingled with a pulverized combustible vehicle therefor, and thoroughlX mixed with the base.

8. briquet comprising fuel oil, an asphalt binder, a quantity of pulverized carbon, and the remainder charred wood sawdust or chips, the amount of oil being limited by the absorption of the charred wood, the

quantity of carbon being suflicient to retain the asphalt in a ulverized condition until compressed, and t 1e quantity of binder being sufiicient to cause cohesion of the charred wood (particles when the mixture is compresse 9. A briquet com rising fuel oil from 2% to 30% by weight, etween 7% and 15% of asphalt binder and the remainder a combustible base 1n finely divided form, the amount of fuel oil being in any referred proportion up to the limit of a sorption thereof b the base, and the percentage of binder being sufficient to cause the.o1l impregnated particles of the base to cohere when compressed.

10. A briquet including fuel oil approximately 16% or 17 by weight, about 11% of asphalt binder, and the remainder a granular combustible base.

11. A briquet containing the ingredients in substantially the percentages by weight named, as fol ows: fuel oil, 16%, asphalt binder, 11%, and carbon 73% in granular and pulverized form.

Signed at Seattle King County, Washington, this 2nd day of November 1923.

PAUL O. MULLIGAN. HERBERT G. SWALWELL.

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