DE1767913A1 - Device for simultaneous drying, shredding and sorting of grainy materials - Google Patents

Description

DR. MÜLLER-BORE DIPL.-INS. 6RALFS 1 7 R 7 Q

DIPL.-PHYS. DR. MANITZ DIPL.-CHEM. DR. DEUFEL '' 0 '"I.

PATENT LAWYERS

June 30, 1968 Fi / Sv - C 924

CHARBONNAGES DE ΪΊΪΑΝΟΕ 9, avenue Percier, Paris 8, France

Device for the simultaneous drying, shredding and sorting of granular materials

The invention relates to a device for the simultaneous crushing, sorting and drying or preheating of granular materials that are "at the drying or preheating temperature not caking.

It is known that the processes of crushing, sorting and drying or preheating of not caking materials can be carried out in a simple manner simultaneously in a fluidized bed reactor, which an impact crusher, e.g. of the type of a cage mill, which is partly or wholly in a fluidized bed of the material to be treated is immersed.

In a known embodiment, the fluidized bed is fed with material to be treated by pneumatic means

hot combustion gases conveying the material by means of ea, which under

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the moving part of the squirrel cage in the fluidized bed arrive. Such a device is described in French patent 1,357,803.

This device has the advantage that it allows the use of combustion gases or gases at much higher temperatures than with a drying or preheating in a conventional fluidized bed, so that a shortening of the contact time between the very fine products and the gases or combustion gases or exhaust gases that entrain them.

In order to introduce the materials to be shredded into the interior of the movable part of the shredding device or the To facilitate the crusher, it has been proposed to divide the moving part of the crusher into several cages that are next to each other and mounted on a common shaft separated by a free space, the ones to be crushed Products, if necessary, guided by means of a deflection device into the interior of cages adjoining this all-directional device will. Such a device is described in French patent 1,444,902.

The invention relates to a device for the simultaneous implementation of the comminution in the fluidized bed, the sorting and the drying or preheating of granular materials which are not at the temperature of the drying or preheating treatment

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baking together, and this device is characterized by the combination of the following elements:

- means for generating a constant flow of hot exhaust gases;

- a fluidizing or swirling tank of rectangular Cross-section with a pyramidal base diverging in an ascending direction and such a cross-section, that the materials to be comminuted assume the state of a fluidized suspension in the container;

a vertical hot gas supply line connected to the base of the fluidization tank and its cross-section is smaller than the cross-section of the fluidization container and which consists of two parts which are connected to one another by a convergent-divergent part;

- a device for feeding the material to be shredded, those in the vafcical supply line of the hot gas between the convergent-divergent part and the base of the vertical fluidization tank flows out;

- a hammer mill with a horizontal axis that is inside the one Area of the vertical fluidization container is arranged in which the products are in the state of a fluidized Suspension located;

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- one with the upper part of the vertical fluidization tank connected discharge line, which is in a pneumatic Delivery line opens, and

- Devices for maintaining the temperature of the fluidized Layer or fluidized bed at a constant temperature value.

The following features of the invention can also be combined with one another and the features listed above:

- The hammers of the mill consist of rods of constant thickness.

- The devices for feeding the material to be shredded consist of a screw belt, the width of the belt being in The direction of conveyance of the materials increases.

- The drain line is at its base with a connector equipped, the cross section of which converges in a vertically increasing direction.

- The height of the base of the connection element of the drainage pipe can be regulated on the floor of the fluidized bed.

- The means for generating a constant flow rate of the hot exhaust gases are made in known manner from a combustion chamber in which a fuel is burned in a neutral combustion.

The means for maintaining the temperature of the fluidized bed at a constant value consist of a motor variable speed, which the screw to feed

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of the material to be crushed, a temperature sensor that is immersed in the fluidized bed, as well as one per se known device for changing the speed of the motor driving the feed screw in direct proportion to the change the temperature of the fluidized bed.

According to one embodiment, the devices exist for Maintaining the temperature of the fluidized bed on one constant value from a temperature sensor immersed in the fluidized bed and a device known per se for changing the fuel flow rate in inverse proportion to the temperature change the fluidized bed.

Further details and advantages of the invention are set out below explained with reference to the drawing; in this shows:

1 shows an overall view of a device according to the invention, FIG. 2 shows a sectional view on an enlarged scale the area in which the actual shredding, drying and sorting of the materials to be treated is carried out will the

3 and 4 show two detailed views of the movable part of the hammer mill, namely in horizontal and vertical section, and

Figure 5 is a partial sectional view of the movable at each end of the. Part of the mill's driving shaft attached Stuffing box.

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The device according to the invention, shown as an example in the drawing, consists of a vertical container, generally designated 1, with a rectangular cross-section, which is connected at its lower part to a combustion chamber 2 and at its upper part to a dusting device consisting of cyclones 3 and 4 consists.

The vertical container 1 can be divided into four areas from bottom to top can be divided into:

a) An area 5 for homogenizing the flow of the hot exhaust gases coming from the combustion chamber 2, which at its upper part has the shape of a convergent-divergent part 6, the outlet cross section of which is smaller than the inlet cross section, so that the ascent rate of the hot exhaust gases is increased .

b) A drying area 7 »in which the in the funnel 8 ge-P stored and introduced to be crushed in the lower part of this drying area by means of a conveyor screw 9 Products are pneumatically conveyed upwards.

c) a crushing zone 10, whose cross-section is larger than the cross section of the drying zone 7, and in such a manner that the velocity of the exhaust gases is reduced in this area and the mass of the entrained by the exhaust gases and intended for crushing products in the form of a

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Adopts fluidized bed 11; the movable part 12 of an impact crusher to be described is in this fluidized bed 11 arranged.

Sighting d) A sorting area 13, in which the sorting by - takes place and the cross section of which is the same as the cross section of the comminution area 10.

The operation of the device according to the invention is best Understandable if reference is made in particular to FIG. 2 and the path traversed by the products to be comminuted is described will. The products stored in the hopper 8 are fed to the base of the drying area 7 by means of the conveyor screw 9. Since the products to be shredded are wet and therefore sticky, a screw belt is advantageously used for this conveyor screw used, the width of the belt increasing in the direction of flow of the products. This type of conveyor screw is in the French Patent 1 4-83 954- described.

Such a feed screw enables continuous withdrawal of the products to be crushed along the entire length of the base of the hopper 8, with the formation of cavities in the hopper and sticking of the products to the walls is completely avoided.

The products to be shredded are driven by the ascending stream the hot exhaust gases and pre-dried.

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10

Because the speed of the exhaust gases in the shredding area / due to the widening of the passage cross-section is reduced »the mass of the products to be comminuted takes the form of a fluidized bed 11 if the relationship between the flow rate of exhaust gases and the passage cross-section in the shredding area is careful is calculated as a function of the granularity of the products to be crushed.

The moving part of a hammer mill 12, which is operated by means of a motor 14 and a drive chain 15 is set in rotation is complete immersed in the fluidized bed. The products to be comminuted are finally dried in the fluidized bed crushed by the hammer 16 between which they come.

In order to promote the penetration of the products to be crushed between the hammers 16 and thus the clogging of the device The hammers 16 advantageously exist to prevent the products from agglomerating under the moving part of the mill of simple rods with a constant rectangular cross-section, as shown in FIGS. 3 and 4-.

The drive shaft 17 of the movable part of the mill is means a known system of bearing and stuffing box with air purge (see Fig. 5) stored in such a way that the seals 18 are protected against contact with the dusty atmosphere and thus rapid wear of the seals and the shaft 17 in the amount of the stock is avoided.

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The area of the vertical tank above the fluidized bed 1 is connected to the conveying line 19, which leads to the dedusting system, by means of a line 20, which is equipped on its lower part with a connecting element 21 which is considered in a vertically ascending direction has a convergent shape.

The sifting area 13 is through the upper level of the fluidized bed 11 and the base of the connecting element 21 limited.

In this area, those which have not been comminuted in the fluidized bed 11 or are insufficiently comminuted and from the Fluidized bed exiting exhaust gases entrained particles and fall back into the fluidized bed 11, where they are a supplementary Crushing are subjected while the dried and crushed! Particles having the desired fineness have reached, be taken along pneumatically through the conveying line 19

To make an effective sorting taking into account the speed To ensure the exhaust gases, it is necessary that the ascending exhaust gases above the fluidized bed have to traverse a "headroom" called height or distance, which sufficient for a regular flow condition to favor sorting.

In other words, the clear height, i.e. the vertical

Distance H, which is the upper level of the fluidized bed from the

Base of the connecting element 21 separates, be sufficiently large

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to allow dropping of the coarse grains that are flung out of the bed and whose rate of descent in the rising exhaust gases is greater than the rate of ascent of these Exhaust gases.

clear
Since the height H to be provided is in principle a function of the granularity to be achieved, the optimal height of the sorting area 13 is set experimentally, internally the distance of the lower end of the connecting element 21 with respect to the upper level of the fluidized bed is changed, e.g. by changing the length of the line 20 .

The pneumatic conveying line 19 guides the dried products consisting of exhaust gases and existing mixture, which are sufficiently comminuted, / to the dedusting system, which has a primary cyclone 3 and a secondary cyclone 4-. The particles captured by the two cyclones are conveyed to their place of use by means of known, but not shown, devices.

Since the exhaust gas generating capacity of the fuel at neutral Combustion is almost equal to its calorific value, it can be assumed that the amount of exiting from the combustion chamber 2 hot combustion gases is constant, regardless of the amount of fuel used.

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There are two ways of regulating the temperature of the fluidized bed:

1. The temperature of the combustion gases leaving the combustion chamber is kept at a constant value by the fact that the fuel throughput as a function of the fuel throughput to be achieved The amount of exhaust gas and thus the amount of combustion air is regulated and that the feed amount of the to be crushed Products as a direct function of the temperature of the fluidized bed ^ j is regulated.

In this case, the device has a temperature sensor 22 immersed in the fluidized bed 11 and a control device 23 known design, by means of which the speed of the the screw 9 driving motor 24- is varied in the same way as the temperature change detected.

2. The amount of product to be shredded will be increased is kept at a constant value and the temperature of the exhaust gases is controlled inversely depending on the temperature the fluidized bed.

The device in this case consists of one in the fluidized bed immersed temperature sensor 22 and a control device 25 of known type, which on a valve 26 in the manner acts that the fuel flow is greater when the

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The temperature of the fluidized bed 11 becomes smaller and vice versa.

Using a hammer mill reduces the risk of that the products to be crushed collect under the moving part of the mill. Such a collection of products can arise at a Carr mill due to the difficulties involved in the grinding process Oppose products if they are to enter the interior of the cage through the bars of this mill.

In addition, the replacement of used elements of the movable part of the mill (essentially the hammer) in one simple operation can be made, including no longer downtime of the device is required.

With the device according to the invention, granular coal was crushed. The properties of this material are in the in the first line of the following table:

Damp
speed 5mm 3, 15mm 2 mm Graininess 0.5mm O, Pnrm 0, 1 mm before the
Crushing 100% 93 ,1% 78% 1 mm 35% 20th ,1% 7, 6% after this
Break up 1.1% 100% 98 , 2% 91.7% 57 62% 45 .7% 25th .6% 78 ,1% *

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The facility operated for three hours with a coal throughput of 9 tons per hour.

and

The exhaust gas temperature was 360 C, / the temperature of the fluidized bed was maintained at 100 ⁰ C.

The shredding and sorting area had the following dimensions: 0.49 m 1 m. The diameter of the moving part of the mill was 0.90 m and the speed of the exhaust gases was at idle in the comminution area 3 »6 m / seconds.

clear

The b'he H was 2m.

The mean value of the characteristics of 27 tons of crushed and dried coal is in the second line of the preceding Given in the table. SHir the treatment was a mean hourly Electrical energy consumption of 17 kilowatt hours, i.e. J2. = 1.9 kilowatt hour per ton of shredded and dried

9
Nice coal required.

In summary, there is a device according to the invention following main advantages:

- Great regularity of operation

- Simply possible automation

- Ease of maintenance and upkeep

- Low consumption of electrical energy compared to known devices, if comparable grain ^ slices achieved should be, whereby this advantage is particularly important.

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Claims (8)

Claims Device for simultaneous comminution in the fluidized bed, Sorting and drying or preheating of granular materials that are at the temperature of the drying or Preheat treatment not caking, characterized by the combination of - Devices (2) for generating an essentially constant throughput of a hot gas stream, - A vertical fluidization tank (1) of rectangular and substantially constant cross-section having a base with a cross-section such that the to crushing materials assume a state of fluidized suspension in it, this base being pyramidal and is designed to diverge in the ascending direction, - A vertical line (5 »6.7) for guiding the hot Gas flow which is connected to the base of the fluidization container (1) and which is connected to the pyramidal Base adjoining part (7) has a smaller cross section than the fluidization container and consists of two Parts (5,7) which are connected to one another by a convergent-divergent part ®, - A device (9) for supplying the material to be shredded, the vertical in which the hot gas flow is guided Line (7) between the convergent-divergent part (6) and 109840/1 366 BATH ORIGINAL the base of the vertical fluidization container (1) opens, - A hammer mill (12) with a horizontal axis, the lower one Part of the vertical fluidization container (1) arranged is, - A discharge line (12), the cross-section of which is smaller than that of the fluidization container (1) and the one with the upper one Part of the vertical fluidization tank is connected, and - of facilities (22, 25, 24, 25, 26) for maintenance the temperature of the fluidized bed (11) at a substantially constant value. 2. Device according to claim 1, characterized in that that the hammers of the mill consist of rods (10) of constant strength. 3. Device according to claim 1, characterized in that that the device for supplying the material to be shredded in a manner known per se from a strap screw (9), the band of which increases in width in the direction of conveyance of the material. 4-. Device according to claim 1, characterized in that that the discharge line (20) at its base with an element (21) for connection to the vertical fluidization container is provided and that the cross-section of this Yerbin- 109840/1366 ^B * D ORIGf _NAL extension element converges in a vertically increasing direction. 5. Device according to claims 1 and 4, characterized in that the height (H) of the base of the The connecting element (21) of the discharge line (20) can be regulated with respect to the fluidized bed or fluidized bed (11) is. 6. Device according to claim 1, characterized in that the means for generating a substantially of the hot gas flow constant throughput in a manner known per se from a combustion chamber (2) in which a fuel is incinerated with neutral combustion. 7. Device according to claims 1 and 3, characterized in that g e that the arrangement for maintaining the temperature of the fluidized layer (11) a substantially constant value is formed by a variable speed motor (24) which the Drives screw (9) for feeding the material to be shredded, one immersed in the fluidized layer (11) Temperature sensor (22) and a known device (23) for changing the speed of rotation of the feed screw driving motor in direct proportion to the temperature change of the fluidized layer. 109840/1366 BATH ORIGINAL 8. Device according to claim 1, characterized in that the arrangement for maintaining the temperature of the fluidized layer at a substantially constant value from a temperature sensor (22) immersed in the fluidized layer and a device known per se (25, 26)
consists, which varies the fuel throughput in inverse proportion to the change in temperature of the fluidized layer (11). 109840/1366 BATH Le first page