US1746767A - Method of producing fuel for industrial and domestic purposes - Google Patents

Description

Feb. 11, 1930. H. DEBAUCHE 1,746,767

METHOD OF PRODUCING FUEL FOR INDUSTRIAL AND DOMESTIC PURPOSES Filed July 6, 1927 5 Sheets-Sheet l URPOSES Feb. 11, 1930., H. DEBAUCHE v METHOD OF PRODUCING FUEL FOR INDUSTRIAL AND DOMESTIC ,P

Filed July 1927 s Sheets-Sheet Feb. 11, 1930. H. DEBAUCHE 3 3 METHOD OF PRQDUCING FUEL FOR INDUSTRIAL AND DOMESTIC PURPOSES Filed. July 6, 1927 5 Sheets-Sheet 3 Patented Feb. 11, 1930 UNITED STATES IBI'U'IBER'JZ' DEBAUCHE, OF NEAR CHARLEROY,IB ELGIUI METHOD OF PRODUCING FUEL FOR INDUSTRIAL AND. DOMESTIC PURPOSES Application filed July 6, 1927, Serial No. 203,860, and in Great l iritain November 29,1926.

Thisinvention relates to the commercial. utilization of lignite, cannel coal and similar carbonaceous matter so that it may be transformed into a fuel of high calorific value.

5 It has been suggested before reducing coal to a finely divided condition for combustion in furnaces, to subject thecoal to low temperature distillation to remove the tar and tar oil content so as to obtain a fragile residue having a volatile content of'about 6% to 18%. On the discharge of this residue from the retort it is quenched with water or steam and reduced to powder.

The present invention relates more partic: ularly, however, to a process described in the specification of prior British Patent No. 254,964 which comprises the subjecting of lignite or the like to low temperature distillation, after which the material whilst retainthat it is possible to so control the method and apparatus that various distinct grades of semi-coke may be produced to serve as:

(a) Direct fuel for domestic grates;

(6) Direct fuel for furnaces for industrial purposes, and

(0) Material graded to any desired size under 5 m/m intended (1) to be agglomerated and made into briquettes of coarse or fine grain as desired, or (2) to be directly used in furnaces constructed'for burning pulverized coal.

This production and grading of semi-coke is facilitated-by the kind of retort or coke oven chosen in which the raw material is first treated or distilled. For example: 7

(1) If a low temperature distillation oven is selected in which the fuel is motionless during the distilling operation or else only moves.

slowly without being energetically disturbed,

then if a non-caking fuel is introduced in fragments as large as 40 m/m in size, semiing a sufiiciency of heat is successively coke. is obtained the fragments of which measure up to 35 m/m.

(2) When a low temperature distillation oven is chosen in which'is placed a non-cak ing fuel notexceeding 10 to 12 m/m in size, and it is moved about energetically during 7 the whole of the distilling operation, then the largest fragments of semi-coke obtained rarely exceed 8 m/m in size.

If the fuel is pulverized before being introduced into the retort, then the resulting product will be pulverulentsem'i-coke.

The object of the present invention is such a treatment of lignite, cannel coal or similar carbonaceous material that after a primary grading of the semi-coke into two definite sizes the larger grade is used directly and the smaller grade is subjected to a second selective grading from which briquettes or ovoids of a finer or coarser grain may be prepared at choice or a grade obtained that ma be directly used in furnaces for burning pu verized fuel. 7

The invention consists in an improved method for the transformation ofjlignite, cannel coal or similar carbonaceous material into fuels of high calorific value, consisting in subjecting the rawmaterial to low temperature distillation, cooling the semi-coke as it issues from the retort or oven screening it so as to obtain a primary grading whereby the aggregate is separated into pieces above and below ,5 m/m respectively, the former being led away for use as a direct fuel that may be further graded if desired, and the latter being led away for a secondarygrading so as to produce semi-coke from 0 to 1/6 m/m, or 0 to 1/ 1 m/m to be pulverized and used di rectly in furnaces constructed to burn pulverized fuel or to produce one or more of a number of grades from 0 m/m to 1/6 m/m, 0 to 1/4 m/m, 0 to 1/3 m/m, 0 to 1/2 m/m, 0 m/m to 1, 2, 3, 4 or 5 m/m respectively, and subsequently agglomerating a selected secondary grade or grades as desired to form briquettes or ovoids, which may be if necessary subjected to further distillation, the above operations being executed progressively, continuously or non-continuously as desired in for a determined sequence-for eachparticular productdesired.-

The invention also consists in apparatus in practice the above-stated method of treating low grade fuels.

Referring now to the accompanying drawi igure 1 is a diagrammaticview in elevation of one form of apparatus.

- '1 Figure 2 is a similar new to Figure 1 of of the apparatus according to a mod1- construction.

Figure 3 is a plan view of Figure 1, and

Figure 4 isatfilan view of Figure 2;

In carrying e invention into effect more especially with reference to Figures 1 and 3, 0 indicates one or more vertical retorts-or ovens into which the lignite cannel coal or the like is fed at the top. These apparatus or, ovens are only indicated by way of example because ovens and apparatus of other may also be used. Figure 3 illustrates by way of example, a battery of six of such retorts and 0' indicates the means by which the desired proportion of volatile constituents is led away from the base of each retort to the usual plant a for there- 'cevery of the tar, benzols, gas and the llke. As the details of this apparatus are well known and do not form part of the present invention, it is not further described. At the bottom of each retort is an outlet 6 for the semi-coke produced.

It has been ,observed by, the inventor that certain semi-cokes obtained from low temperature distillation ignite spontaneously upon contact with the air, that is upon removal from the retort, and means are therefore provided to cool the semi-coke, but the extent of such cooling is however variable according tothe use which isto be made of the semico ke. Thus where the product will be-subsequentl agglomerated the semicoke will be coole down to about 180 C. so that there will be no necessity for any .intermediary re-heating to facilitate its manufacture into briquettes or ovoids, but ifthe semi-coke is to be stored it is cooled down to about 40 C.

For this purpose as the semi-coke leaves the outlet 11 it is received in a chamber a closed ofi from the atmosphere and cooled by a water circulating s stem of which d is the inlet pipe and e t e outlet. This cooling chamber is particularly described in the specification of British Application No,

"18159 of 20th July 1926. l The fuel upon leaving the chamber 0 is received b a closedin screen g of any usual construc tlon where a primary separation is effected into two grades, viz, pieces above 5 m/m in .size that remain on the sieve, and pieces under 5 m/m that pass through. .The larger grade passes by way. of a chute h down to a conveyor 7: by which it is carried away to a storage, each retort having its own chute, and all the chutes serving the conveyor 70. Both the conveyor and the chutes are closed in by suitable means so as to prevent the difiusion of dust in atmosphere which might thereby cause an explosion, and if desired, these enclosed spaces may be filled with an inert gas.

It is to be noted that this primary separation of the fuel takes place as close as possible to the coolin chamber a as it is of advantage that -at east the larger grade of 5 m/m and upwards shall not receive any unnecessary handling owing to its friable nature. This separated larger grade is intended for direct burning as in domestic firegrates, and furnaces of steam boilers and to suit it to these respective pur oses it may for instance be subjected to furt er screening at the end of the conveyor is to obtain (firstly) an aggregate of a size from 5 to 8 m/m adapts.

ed to be burned in the furnaces of steam boilers and (secondly) an aggregate of 8 m/m and above suitable for domestic fire-grates. The aggregate which passes through the screen 9 of a size from 0 to 5 m/m to be subse- Huently pulverized or agglomerated is led own a closed chute Z from each retort, and all discharge into a conveyor m from whence by means of a duct n it passes into the lower end of a. completely closed conveyor 0 by which the aggregate is raised and transferred to a duct 1 which delivers it either into a pit g or onto a screen 1'. In a case where the aggregate coming from the retort is in a pulverulent condition, the screen 1' is moved so that it falls direct into the pit g, from whence it is taken by the conveyor u to the agglomerating plant or by another conveyor which directsit to a furnace constructed for burning pulverized coal, but when the aggregate is of a size between 1 and 5 m/m inclusive the screen r is moved into th path of the falling aggregate and caught. en making agglomerate from semi-coke of 0 m/m to 5 m/m the semi-coke coming through the conveyor 0 is carried to the duct 2 which delivers it directly to the pit g without it passing through the screen 7'.

' e screen 7' is used to determine the granular structure of the briquettes or ovoids that are to be produced, whether it is to be fine or coarse. For instance if the grains are not to exceed 2 m/m in size, then a screen a is placed in position to catch the aggregate up to 5 m/m.

All the grains below 2 m/m will pass through the screen and fall into the pit q, but the grains above this size pass along the screen and are led away to a crusher s and after being treated therein it falls into a pit t, from whence it is raised by a conveyor j and is returned to the conveyor 0 to again pass the screen r the aggregate being new of the requisite size and being delivered to the pit g. Thus by changing the screen to the size required, so the aggregate delivered to the pit g will be of the corresponding size, and whilst that particular screen is in position, the pit will receive that size only. a

For a simplification of the plant, a modification may be usedv as indicated in Figures 2 and 4, according .to which the screen 9 below each oven or retort is omitted, and replaced by a single screen g placed immediately in front of the screen 1', All of thesemi-coke produced by' the oven and coming from the chamber 0 falls into a duct 1, the series of which all lead the semi-coke to the conveyor m from whence by means of the duct 7!. it passes into the lower end of a completely closed conveyor 0 by which the aggregate is raised and transferred to the screen g of any usual construction where a primary separation is effected into two grades, viz, pieces above 5 m/m in size that remain on the sieve, and those under 5 m/m that ass through.

The larger grade is passe on to the conveyor k by which it is carried away to storage. The aggregate however which passes through the screen g of a size from 0 to 5 m/m to be subsequently agglomerated or pulverized by'the crusher s for use in furnaces specially intended to burn the pulverized fuel, passes on the screen 1' which is arand agglomerated wfuel possessing exception-- ranged as above described.

When it is desired to produce a compressed ally high cohesion and having very feeble permeability to water, it is necessary to crush the semi-coke very fine and therefore in this case a screen '7' would be employed having a mesh narrower than 1 m/m.

When however the semi-coke is to be pulverized so that it may be burned in furnaces adapted to burn pulverized fuel, it will be necessary to select a'very fine screen 1' capable of producing semi-coke of O to 1/6 m/m and 0 to 1/4 m/m which will be pulverized at the place where it is to be used by any welllmown apparatus, the semi-coke refuse being" always directed toward the crusher s and the productfrom said crusher being returned to the screen 1"; the fuel that has however passed through the sieve will not be conducted towards the agglomerating plant-but willfall into the pit g from whence it is taken by a vl P 1 1 8 depends upon the position gt a flap chain or other conveyor which will deliver it to wagons or magazine hoppers or to where it isto bedirectly used. f

It is possible toreplace the screen 1* and the crusher s mentioned above by a crusher adapted to supply. a semi-coke crushed to the size required. 7 I

Returnin to Figures 1. and 3, from the pit g,= the aggregate of the size chosen is raised by another completely closed conveyor 1; and fed to one of two conveyors 'w', m, which supply it to one of two towers y, z, respective- Which of these conveyors and towers and the smaller of the two towers 2 on its way to be agglomerated.

Should there be however a stoppage in the agglomerating part of the plant, the valve 10 is adjusted into its alternative position to deflect the aggregate to the conveyor w and thence into the towery, this being of larger capacity intended to act for storage. With the regular operation of the plant the small capacity of the tower z is sufficient so as to avoid any accumulation which is undesirable in View of the temperature'of the aggregate and that no cooling is desirable at that stage of the process. Owing, however, to the greater capacity of the tower y and the accumulation of heated aggregate that will take place therein when and if it is used, it is to be understood that the semi-coke will be cooled down to 40 C. in the chamber a of each of the retorts or ovens, this being effected by increasing the fiow of cooling water by means of a valve fitted in the pipes d or/e or both.

The lower ends of the towers y, z, converge at one outlet 11 where a suitable measuring device 12 permits definite charges of aggregate, or controls the discharge thereof during a given time, into one end of a conveyor 13. Alongside of the tower y, z is arranged another tower 14 which contains a pulverized binder such as pitch which is supplied from a crusher l5 and fed from thence to the tower 14; by conveyors 16, 17. The discharge of pitch is controlled by a measuring device 18 whence it passes into the other end of the conveyor 13. The two measuring devices 12 and 18 deliver to the conveyor 13 the proportionate quantities ofaggregate and pitch and these are mixed together and discharged from the conveyor by the fact that it is a worm conveyor, the threads of which at each end are respectively right and left hand. The

action of the worm therefore draws the aggregate and pitch towards one another so that they are discharged together at the common outlet 19 from whence they pass in a mixed condition to a conveyor 20 in which their mixing is finished and are led away to be briquetted. In the example shown, the towers y, z and 14 are du licated and two conveyors 20 are used for eading away the v mixed aggregate, thus one of the conveyors 20 passes it by way of a mixer 21 to a briquet ting press 22 from which the finished briquettes pass by the conveyor 23, and the other conveyor 20 forwards the mixed aggregate by way of mixer 24 to an ovoid;making press 25. From this latter press the ovoids are delivered to a storage 26, or if desirable they are passed by way of a chute 27 to a retort or oven 28 to distil off any excess of volatile -content, so that it may be recovered. The fuel thus treated may be considered as smokeless burning fuel having very high cohesion and calorific value so that it is comparable to the best anthracite for use in domestic fire-grates.

By the foregoing arrangement it will be 5 understood that depending upon the kind of screen r selected, so the semi-coke may be pulverized as desired and briquettes or ovoids may be made of an aggregate formed of pieces ranging from to 1, 2, 3, 4 or m/m 1o respectivel and varying in granular structure from ne to coarse.

It has been observed in the course, of experiments that with an industrial low temperature distilling retort of class No. 1

(where the fuel is substantially motionless) when there was placed in an oven in 8 consecutive days approximately 100 tons of lignite containing of water and the frag ments of which varied from 0 m/In to 1 m m/m, there was produced a semi-coke containing: firstly, approximately of fuel of a size varying from 5 to 30 m/m (of which 2/3rds was of a size from 5 to 8 m/m whilst the remaining 1/3rd was of a size between 8 to 30 m/m); secondly, approxia distilling ovens or retorts are characterized by being completely deprived of moisture; they usually contain 8 to 12% of volatile substances but this can nevertheless be reduced to only 3 to 4% of volatiles, where it is de- 0 sired to manufacture an agglomerate comparable with anthracitefi In spite of thesmall volatile content, they burn admirably and give out an extreme heat, with absolutely no smoke, very easy ignition and for an ash content of 6% their calorific 3 value exceeds 8,000 calories, per kilogramme. These semi-cokes therefore form a fuel of (the first order and they must be used when possible in the state in which they are prom duced, that is'tosay, without any further preparation.

It has been observed that the fragments of semi-coke the dimensions of which vary from 5 to 8 m/m, burn perfectly in the furraces of steam boilers, upon grates the bars of which are spaced about 4 m/m apart approximately and that an aggregate that exceeds in size 8 m/m and up to 30 m/m can be successfully used in domestic fire-grates. 00 Also in the course of experiments, there have been manufactured 5 grades of compressed fuel of a. size from 0 m/m to 1 m/m 0 m/m to 2 m/m-3 m/m4 m/m-5 m/m. "During combustion the five different agglomerateshave-given the same calorific value,

but the agglomerate manufactured with semicoke of a size from'O m/m to 1 m/m gave maximum cohesion and density for a minimum capacity for absorbing moisture whilst requiring more pitch.

On the contrary, the agglomerate manufactured with semi-coke 0 m/m to 5 m/m, gave the minimum cohesion and density with a maximum-capacity for absorbing moisture whilst requiring less pitch.

It can be concluded that the finest semicoke will give the hardest agglomerate, the most dense and the least pervious to water, whilst the semi-coke of larger size will give ,a compressed fuel which is the least hard,

the least dense and the most pervious to water.

It has been found that after testing the cohesion of the agglomerate obtained with semi-coke of'0 to 5 m/m in size was 25% less than that of the agglomerate obtained with the semi-coke of fragments 0 m/m to lam/m whilst the difference between their densities was 6%.

After a complete immersion in water f0 30 consecutive hours, the agglomerate ob- Y tained with the semi-coke of fragments 0 to 5 m/m absorbed 4 times more water than the agglomerate obtained with the finest, that is 0 to 1 m/m.

As regards the quantity of pitch employed for the agglomerate of 0 to 5 m/m, it was less than for the aggregate of 0 to 1 m/m 1 by about 7.50%.

With the intermediate fuels, that is to say 0 to 2 m/m, 0 to 3 m/m and 0 to 4 m/m, the differences were practically proportional.

It is evident also that with a semi-coke of which the coarser size is below 1 m/m m/m1/3rd m/m, m/m or otherwise) it is possible to obtain more cohesion and density than with 0 m/m to 1 m/m.

In conclusion, the foregoing description discloses a system and apparatus for the transformation of fuel which is usually regarded as of low grade value into fuels of high value which system may be carried on continuously or non-continuously.

There is no danger of fire from the use of the apparatus, andthe apparatus may be constructed so as to form an unbroken system of operations or so constructed that the operations may be intermittent or continuous as desired.

Having now described my invention, what I claim as new and desire to secure by Let- 'tion to below 180C. as it issues from the retort and before it is exposed to air, screening the solid portion while still warm whereby the aggregate is separated into pieces above and below 5 m/m respectively, the former constituting a fuel capable of further grading, subjecting the latter to a-selective secondary screening, and dividing the selected screen-.

ings obtained to be agglomerated while still warm to form briquettes, in one case, and to be led away so as to be used for making a pulverized fuel in the other case.

2. A method as claimed in claim 1, in which the oversize screened material from the selective secondary screening while still warm is submitted to crushing and the

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