DD223935A1 - ROTATING DEVICE FOR SWIVEL LAYERS WITH CLASSING DROP - Google Patents

Abstract

The invention relates to a stirring device for fluidized beds for granular drying of thermolabile solutions, suspensions and melts. The object and the object of the invention is to enable a Granuliertrocknung for products with high bond strength by means of a device in which the well-known principle of classifying deduction should be used, which works stoerunanfaellig, no sticking of the fluidized bed, running with a high degree of automation and at the maximum air inlet temperatures are used. According to the invention, specially designed stirring arms are arranged in a fluidized bed space, which consist of vertically placed and inclined sheets, wherein an angle α, which is 90, is always formed between any symmetry axis of the apparatus and the Tengente on the armature arms at the intersection between the axis of symmetry and the tangent. The upper Ruehrarme are each arranged in mirror image to the lower. The invention is applicable in the food and chemical industry as well as agriculture.

Description

(cos t +1 · sin t)

/ ^D A ~ ^2d K y = (- -z J (0.5 + 8.3λ / <^ (sint-tcost)

and the shape of an upper stirrer arm (7) can be described by the following equations:

^D A ~ ^2d

/ ^D A ~ ^2d KX

= (- - + 0.01t j (cost + tsint)

D -2d _ ·

y = .- ^ (1 + 8,3 "yd _K (sint-tcost)

wherein the upper stirrer arms (7) are mounted in mirror image to the lower stirrer arms (8) directly on the shaft (6) and the lower stirrer arms (8) on a central ring (9), for whose outer diameter D _R <D _A - d _K applies and the ring (9) by fasteners (10) on the central shaft (6 ^{1 is} attached.

2. agitator for fluidized bed apparatus according to item 1, characterized in that the direction of rotation of the shaft (6) is set so that the vector of the angular velocity (w) always in the direction of between the axis of symmetry (c) and tangent to the lower Rührer (8) formed angle (a) or (<* '), which is greater than 90 °, while the upper Rührerarm (7) is reversed the Fail.

3. agitator for fluidized bed apparatus according to item 1 to 2, characterized in that the stirrer arms are inclined in the vertical at an angle of at most 45 ° so that in each case the lower edge of the lower Rührer arm (8) leads in the direction of rotation of the upper edge, while the upper Rührerarm the upper edge of the lower edge leads.

4. agitator for fluidized bed apparatus according to item 1 to 3, characterized in that the distance between the upper edge of the inflow bottom (2) and lower edge of the lower Rührer arm (8) is smaller than d _K.

For this 3 pages drawings

Field of application of the invention

The invention relates to a stirring device for fluidized beds with classifying deduction, which can be preferably used in the chemical industry, in agriculture and in the food industry, and where thermolabile solutions, suspensions or melts must be dried granulier without thermal damage to the Product should occur.

Characteristic of the known technical solutions. ..

For Granulationstrocknung of solutions, melts or suspensions devices with classifying deduction are known, DE-OS 2901723. In these devices, the liquid via liquid distribution devices, such as. As nozzles, introduced into a fluidized bed. The wetting of the fluid particles in the fluidized state with liquid and the evaporation of the solvent results in continuous granule growth. Through the classifying trigger, a stream of air flows upwards at a constant speed. All solid particles that have reached a diameter and a mass that corresponds to the rate of fall and thus the speed in this classifying deduction can pass through the exhaust pipe and get out of the apparatus via a Feststoffabförderorgan as an end product.

Of crucial importance for the functioning of such devices is a high turbulence in the fluidized bed and thus a high particle velocity. Due to this high turbulence, there is a good mixing of the particles in the fluidized bed and thus a good distribution of the liquid to all solid particles. However, a high particle velocity can only be achieved by multiplying the vortex point velocity. , , , , -

Injection of liquids with high viscosity and high bond strength, it is also, especially for small solid particle diameters, often for agglomeration of entire solid particle collectives that do not separate from each other and eventually lead to the collapse of the stable operations of the fluidized bed and thus the accident state.

-I- ^ DU / OO U

There are known solutions in which attempts by mechanically moving internals to destroy the resulting agglomerates in the fluidized bed again, DE-OS 2602454. However, it inevitably leads to a destruction of small granules and increased abrasion, the dedusting for the Exhaust air additionally charged.

Another attempt to prevent the above-mentioned agglomeration effects in practice, by creating a directional stable flow in the fluidized bed, consists in the solution described in WP 119304, in which the opening ratio of the inflow base and thus the gas velocity immediately above the ground from the center increased to the periphery, which has an upward movement of the particles on the outer diameter of the fluidized bed apparatus and a downward movement in the center result. These flow conditions are thermolabile, especially for granulation drying. Low substances, since the freshly wetted particles move in the center of the apparatus from top to bottom and transported directly above the distributor plate in the radial direction from the inside out. Thus, the most heavily loaded with liquid particles reach the warmest points of the apparatus, whereby damage to thermolabile products is largely avoided. However, this cheap known solution has the disadvantage that they are at high fluidized beds, as z. B. for granulation drying sticky goods are required, fails, since from a certain layer height, the above-mentioned flow effects, especially at low gas velocities, no longer form.

Object of the invention

The object of the invention is to effectively carry out granulation drying, which has heretofore been uneconomical by other drying devices, for products having a high adhesive force. The device according to the invention is intended to run without interference with a high degree of automation and the work productivity should be substantially increased. By increasing the quality of the granules produced significant economic effects are to be achieved. In addition, accidents and production losses should be largely avoided by gluing the fluidized bed.

Explanation of the essence of the invention

The invention has for its object to provide a stirring device for fluidized beds with classifying deduction, which allows granulation drying in a fluidized bed with complex facilities granulationstrocknungsfähige solutions, melts or suspensions continuously and poduktschonend. It should not come to a sticking of the fluidized bed by agglomeration. The highest possible air inlet temperature should be used without damaging the product to be dried thermally. The well-known principle of classifying deduction in the apparatus axis should be used. The object is also to operate a fluidized bed under injection conditions in the range of the vortex point velocity and below stable. According to the invention the object is achieved in that in a known cylindrical or slightly conical fluidized bed apparatus with classifying deduction directly above the upper opening of the central exhaust pipe in the apparatus axis a rotatable shaft is arranged. The central exhaust pipe is known to be open at the top and limited by a Feststoffabförderorgan down, and between Feststoffabförderorgan and the upper opening of the exhaust pipe opens a gas supply pipe into the central exhaust pipe.

On the rotatable shaft one or more Spezieil trained stirrer arms are mounted in two different heights. The stirrer arms consist of vertically positioned or inclined sheets of height H. These stirrer arms are designed so that in the plan view between an arbitrary axis of symmetry of the apparatus and the tangent to the stirrer arm at the intersection between the axis of symmetry and tangent always an angle is formed. It has been found that the desired effect for achieving a defined flow regime occurs best when both lower and upper stirrer arms assume a very specific mathematically describable shape, which surprisingly depends on the diameter of the granules produced. The direction of rotation of the central shaft is set so that the vector of the angular velocity always points in the direction of the angle formed between the axis of symmetry and the tangent to the lower stirrer arm, which is greater than 90 °, whereas this is reversed in the upper stirrer arm.

E ^ belongs to the invention that the upper stirrer arms are each arranged to the lower mirror image and that the upper stirrer arms are mounted directly on the rotatable shaft. The lower stirrer arms, however, are attached to a central ring, which in turn is fixed to the central shaft. The outer diameter of this central ring should be less than or equal to the difference between the inner diameter of the central exhaust pipe and double granule diameter. ,

In addition, part of the invention that the stirrer arms are inclined in the vertical at an angle of at most 45 ° so that in each case in the direction of rotation, the lower edge of the upper or the upper edge of the upper Rührerarms leads. According to the invention, the device functions so that a defined flow regime for the solid particles is created by the arrangement of the upper and lower stirrer arms in the fluidized bed. The design of the stirrer arms causes the solid particles in the center of the apparatus to be pulled down where they are exposed to the classifying action of the trigger. All freshly wetted by the nozzles solid particles are quickly guided by the conveying action of the lower stirrer arms immediately above the distributor plate, ie at the point at which the gas has the highest temperature, from the inside to the outside. By adjusting the stirrer speed, this movement can be influenced relatively independently of the gas velocity by the stirrer speed.

In this way it is possible to use high gas inlet temperatures without thermal damage to the product, since a maximum cooling limit temperature is applied to the surface of the freshly wetted solid particles. At the outer diameter of the apparatus, the solid particles drift upward again and are guided in the region of the upper stirrer arms by their mirror-image arrangement back to the center of the apparatus. By this arrangement, the defined flow regime described is maintained continuously, which in addition to the mentioned favorable driving force utilization without product damage mainly means that the tendency to agglomerate sticky goods due to the high turbulence in the layer and the uniformly fixed flow path for all particles For the first time, the device according to the invention can be granulation-dried to obtain new product properties. The effect described is further enhanced by a slope of the Rürjerrer arms against the vertical of a maximum of 45 ° and by attaching the liquid distribution devices directly to the upper stirrer arms.

embodiment

The invention will be explained in more detail with reference to an embodiment. The accompanying drawings show in Figure 1: Schematic diagram of the device, Figure 2: Section A-A of Figure 1, upper paddle and Figure 3: Section B-B of Figure 1, lower paddle

The device consists of a slightly conical fluidized bed apparatus 1. The diameter of the inflow base 2 is 600 mm, the diameter of the central exhaust pipe 3 70 mm. In the central axis of the apparatus 1, a rotatable shaft 6 is arranged with a diameter of 30 mm, which ends directly above the upper opening of the central exhaust pipe 3. The central exhaust pipe 3 is closed at the bottom by a rotary valve 4 and has laterally a gas supply pipe 5. At the lower end of the rotatable shaft 6 fasteners 10 are mounted, which hold a ring 9. At this ring 9, two lower Rührerarme 8 are attached. These lower stirrer arms 8 are formed by vertical plates of height H = 100 mm. These stirrer arms 8 are shaped so that their wings in section B-B satisfy the following equations given the assumption of a Cartesian coordinate system in the apparatus center point: χ = 0.07 (cost + · sint),

y = 0.0761 (sin t + · cos t)

The direction of rotation of the shaft 6 is seen from above to the right.

Via the lower Rührerarm 8 a second upper Rührerarmpaar 7 is attached at a distance of a = 250 mm from the upper edge of the lower Rührerarme 8, the attachment to the rotatable shaft 6 is offset by 90 ° relative to the lower pair of stirrers 8. ·

In contrast to the lower pair of stirrers 8, the upper stirrer arms 7 are designed so that they are in the view from bottom to top in the cutting plane A-A on the assumption of a Cartesian coordinate system in the apparatus center. satisfy the following equations: χ = (0.015 + 0.011) (cos t + t sin t)

y = 0.0328 (sin t - t · soc t).

The height H of the upper stirrer arms 7 is also 100mm. Below the inflow base 2 is a gas distribution chamber 12, in which a gas supply pipe 13 opens. Above the layer, the solvent-laden gas exits the apparatus via gas exit pipes 14. Immediately below the upper stirrer arms, there is attached a liquid feed tube 15 leading into a single-fluid nozzle 11. The single-substance nozzle 11 points downwards and is mounted in the middle between the apparatus axis and the apparatus wall.

Claims (1)

Invention claims:. · 1. Stirring device for fluidized bed apparatuses with classifying deduction, in which a drain pipe is mounted in a cylindrical or slightly conical fluidized bed apparatus in the middle of the inflow, which is open at the top and down by a suitable Feststoffabförderorgan such. B. a rotary valve is limited, wherein between Feststoffabförderorgan and the upper end of the tube, a gas supply pipe opens into the central exhaust pipe and in the central axis of the apparatus a rotatable shaft is arranged, which ends directly above the mouth of the central exhaust pipe and to the in two Stirrer arms, which consist of vertical or inclined sheets of height H, are mounted, characterized in that between any symmetry axis (c) of the apparatus (1) and the tangent to the stirrer arm (8) at the intersection between the axis of symmetry and tangent always a constant or changing angle α or α is formed, wherein the stirrer arms (8) are preferably formed such that in a horizontal section through the apparatus (AA), (BB), assuming a catholic coordinate system in the apparatus axis, the shape of a lower stirrer arm (8) in parameter representation by the f the following equations: