US1518186A - Agglomeration of powdered or finely crushed materials, more particularly fuel, by means of pitch - Google Patents

Description

Patented Dec. 9, 1924.

UNITED STATES PATENT; OFFICE.

HENRI DU BOISTESSELIN, OF BOUEN, FREDERICK WILLIAM v'JJAIBB, O'F PARIS, AND LEON HERTENBEIN, OF LEVALLOIS-PERRET, FRANCE, ASSIGNORS OF ONE-FIFTH IO QCTAVE DUIBOIS AND ONE-FIFTH TO LEON VARNIEBI, BOTH OF ROUEN, FRANCE.

AGGLQMERATION OF POWDERED OR FINELY CRUEEHED MLA'J?IEIBIIALS,v KOBE PAR- TICULARLY FUEL, BY MEANS OF PITCH.

No Drawing.

To all whom it may concern:

Be it known that we, HENRI DU BOISTES- SELIN, a citizen of the French Republic, residing at Rouen, France, FREDERICK W1L- LIAM TABB, av subject of the King of Great Britain, residing at Paris, France, and LF'JON HEnrnNBnIN, a citizen of the French Republic, residing at Levallois-Prret, Seine, France, have invented a newand useful Improvement in Agglomeration of Powdered or Finely Crushed Materials, More Particularly Fuel, by Means of Pitch, of which the following is a true and exact description. i

This invention relates to a process for the agglomeration of powdered or finely crushed materials, and more particularly fuel, by means of pitch.

In practice, for the agglomeration of these materials and especially fuel in a more or less finely ground state is mixed with the dust to be agglomerated, and then the whole is introduced into a mixer, usually heated by steam, in such a manner as to melt the pitch and to enable it to be dis-' tributed throughout the mass. The paste obtained is then moulded 'whilst it is still hot and plastic.

The more finely the,pitch is ground, the more uniformly will it be distributed throughout the mass and this more efficient distribution produces a slight reduction in the percentage of pitch necessary for the agglomeration. i

In some plants melted pitch is used, that is to' say, a mixture of dry pitch and tar raised to the melting temperature before being mixed with the coal dust. This method of operation enables the proportion of pitch employed to be reduced (to about 5%), in comparison with the processfirst referred to but the agglomerates obtained generate a dense smoke when burning.

According to the present invention, the pitch, serving to agglomerate the powdered or finely crushed materials, and more particularly fuels, is suspended in water insuch a manner as to form a pseudo-solution, before being mixed with theimaterial to be agglomerated. I

The mass or paste obtained by mixing, whilst cold, the material to be agglomerated with a suitable proportion of the pseudodu'st, dry pitch Application filed May 7, 1923. Serial No. 637,330}

' solution of pitch may then be introduced into a press, and the agglomeratesobtained may be dried by heating.

- The drying is preferably effectedby heat perature which ensures the distillation and the removal ofthe volatile products of the pitch by the steam which isevolved.

ing the agglomerates in a stove at a tem- By placing thepitch in suspension in wanecessary varies from 2 to 470' for the ag glomeration of fuel-dust -(coal, coke, anthracite, etc.,) instead of the proportion of 7 to 10% necessary in the usual plants,-

the combustible agglomerates. obtained according to theprocess forming the subject of the invention burn without producing smoke or odour by reason of the removal of the volatile elements of the pitch during the heating of the agglomerates.

One satisfactory mode of procedure in carrying out the invention is as follows:- 1 The pitch, coarsely crushed as usual,-is then ground by using water as'the dispersing agent; this grinding can be effected in anysuitable apparatus such for example as a ball mill or pulverizer. The proportions of water and pitch may vary within very wide limits; good results are; obtained by using equal parts by weight of water and pitch.

The pitch, thus brought into suspension in water, is distributed in the latter in a in grinding the pitch, substances adapted to increase the agglutinant power of the solu- .solutions of pitch in the same way that it acts in relation to pseudo-solutions of graphite. It delays fiocula-tion, that is to say, the settling or precipitation of the pitch, and for this purpose it may be used in the same proportions as dextrine, the extracts of cellulose, etc.

We have found that it is possiblev to obtain commercially pseudo-solutions of pitch with a high content of pitch. This content may exceed 70% by weight of the solution,-

which is advantageous in certain industries, especially in the industry for the agglomeration of coal.

The pitch solution is added to the dust to be agglomerated in such a manner as to introduce 2 to 4% of pitch. The whole is suitably mixed whilst cold; and then the mass is passed through a press into moulds whic -may or may not beheated.

The agglomerates when leaving the press re si'ibjected to a suitable drying operation; in the case of fuels the drying is preferably effected in a' stove, heated in any suitable process according to the manner so as to raise the temperature of the agglomerates to a temperature of about 200250 C. In view of the very fine division and intimate mixing, molecule by molecule, of the pitch and water in the mixture, there is produced a thorough distillation of the pitch by the removal, by means of the steam, of the volatile products contained in the pitch, which thus escape, so

.that after this treatment the. fuel agglomerates burn in grates without evolving smoke or odours. Another advantage, due to the resent invention, is that the agglomerates have no tendency to stick together in the grates, which is a disadvantage! observed with ordinary agglomeratesmade with pitch.

To the pitch solution may also be added,

before it is mixed with the fuel dust, oxidizing agents such as chloride of lime, nitrates of metals having two degrees of oxidation, such as the nitrates of iron, chromium, cobalt, etc.; these oxidizing agents are employed in small proportions for example "from 0.1'to 0.5% of the fuel. These' additions, at the time of the 'thermic treatment mentioned above, serve to oxidize the The following are examples of the application of the invention to the manufacture of agglomerated fuels Example I. 100 parts of anthracite dust containing 7% of water are mixed with 8 parts of a 50% pitch solution.

-Example H.100 parts of Cardiff coal dust are mixed with 8 parts of a 50% pitch solution and 0.2 parts by weight of chloride of lime.

Example III. 100 parts of anthracite dust are mixed with 6 parts of a 50% pitch solution, diluted with 4 parts of water.

Example IV. 100 parts of Cardiff coal dust are mixed with 1 parts of a 50% pitch solution, diluted with 6 parts of water, to which are added 0.2 parts of cobalt nitrate. It will be understood that these examples are only given by way of explanation.

Instead of introducing the mass or paste, resulting from the mixing of the material to beagglomerated with the pseudo-solution of pitch, into the press and then drying the agglomerates obtained by heating, it is possible, according to the second method of carrying the invention into effect, to heat this mass or paste to the melting temperature of the pitch, which is generally 60 to 80? C. for the pitch of the coal usually em ployed in the agglomerating industry, before introducing it into the press, as is usual in the present manufacture of agglomerated fuels.

The paste may be heated in any-.suitable apparatus, but is preferably effected in an apparatus comprising heating. surfaces; finally a stream of hot air is passed through the mass of hot paste for the purpose of removing the excess of moisture therefrom (above 2.5 to 3%) due to the water contained in the pseudd-solution of pitch or due to the Humidity of the dust employed.

A an example a double-walled cylinder may be employed; heated by steam, hot water or combustion gases, whilst a hollow spiral, or inclined blades arranged in the form of a spiral in the interior thereof, produce by their movement a constant variation of the contact of the mass of paste with the heating surface and with the hot air passing through the cylinder, along the axis thereof, in the opposite direction to the material which is fed'forward by the'movement of, the spiral or of the blades.

The following are a few examples of the application of this second methodof operation.

Example V. 100 parts of Cardiff fine coal, of 4%humidity, are mixed with8 parts of a pseudo-solution of pitch, containing pitch, so that about 5 parts of pitch and 3 parts of water are introduced into the mixture.

After mixing, whilst cold, the paste isheated to about .to 80 0., whilst the air, also raised to this temperature, is passed through this paste in order to remove 4 parts of Water therefrom.

Example VI. 100 parts of fine anthracite, with 1% water, are mixed with parts of a pseudo-solution of pitch, with pitch, so that about 5 parts of pitch and 2 parts of water are introduced. After mixing, the mass is heated to 60 to C. without passing hot air through the interior of the heating apparatus.

It will be understood that these examples are only given by way of explanation.

What we claim is:

1. A process for the agglomeration powdered or finely crushed materials, and more particularly fuels, consisting in suspending pitch in water, so as to form a pseudo-solution, in mixing, whilst cold, the

materials to be agglomerated with a suitable proportion of said pseudo-solution,-in com.- pressing said mass, and drying by heat the agglomerates obtained, at a temperature of about 200250 U. adapted to ensure distillation and removal of the volatile products of the pitch.

2. A process for the agglomeration of powdered or finely crushed materials, and more particularly fuels, consisting in suspending pitch-in water, so as to form a pseudo-solution, adding to said pitch solution gummy, resinous or mucilaginous substances adapted to increase the agglutinanr.

power of the said pseudo-solutions, in mixing, whilst cold, the materials to be agglomerated with a suitable proportion of said pseudo-solution,-in compressing said mass, and drying by heat the agglomerates obtained.

3. A process for the agglomeration of powdered or finely crushed materials, and more particularly fuels, consisting suspending pitch in water, so as to form a pseudo-solution, adding to said pitch solution oxidizing agents adapted to facilitate the removal of the volatile products of the pitch by heat, in mixing, whilst cold, the

materials to be agglomerated with a snitable proportion of said pseudo-solution,- in compressing said mass, and drying by heat the agglomerates obtained.

4. A process for the agglomeration of powdered 'or finely crushed materials, and more particularly fuels, consisting in suspending pitch in water, so as to form a pseudo-solution, adding to said pitch solu tion gummy, resinous or mucilaginous substances adapted to increase the agglutinant power ofthe said pseudo-solutions, and oxidizing agents adapted to facilitate the removal of the volatile products of the pitch by heat, in mixing, whilst cold, the materials to be agglomerated with a suitable proportion of said pseudo-solution -in compressing said mass, and drying by heat the agglomerates obtained.

In testimony whereof we have signed names to this specification. I

HENRI DU BOISTESS'ELIN. FREDERICK WILLIAM TABB LEON HERTENBEIN. Witnesses:

J. ARMENGANDAINI. ll. Dnrr'xonlnon'r.