DE4241299A1 - Liq. treatment to form fine suspension or emulsion - e.g. in treatment of contaminated soil slurry or waste water - Google Patents

Abstract

In a process for treating liq. such as an aq. slurry of contaminated soil and/or waste water by-prodn. of a fine suspension or emulsion, the liq. circulates from the bottom of an inner container to the bottom of an outer container and from the top of the outer container back to the top of the inner container. The novelty is that (a) the liq. is exposed to shear forces in the gap between a rotor, located in the inner container, and a stator formed by at least a section of the bottom and/or lower wall region of the inner container and (b) the liq. is forced by the rotor from the bottom of the inner container through stator openings into the bottom of the outer container. Also claimed is appts. for carrying out the above process. ADVANTAGE - A very fine, uniform suspension or emulsion is produced in a simple manner.

Description

The invention relates to a method for treating liquid, as in Slurried contaminated soil and / or wastewater Create a fine suspension or emulsion, circulating the liquid flows from the bottom area at least one arranged in an outer container Inner container to the bottom area of the outer container and from the upper area of the Outer container back to the top of the inner container. The other relates the invention relates to a device, in particular for carrying out the method, consisting of a preferably cylindrical outer container with preferably conical bottom and an inner container arranged in the outer container ter that in the cylindrical or conical lower wall area and / or floor area for liquid flowing to the outer container and above for back from the outer container flowing liquid is open.

The general rule is that all processes of mass transfer between two phases (solid-liquid in the case of a suspension and liquid-liquid in the case of an emulsion), if the phase interface is increased, which is achieved by crushing the particles or Drops can occur.  

It is particularly important when washing contaminated floor material on the fact that the soil material is slurried very finely. That means that Solids to very fine particles with a diameter in the micrometer range are divided. By creating a very large solid / water interface promotes the dissolution of the contaminants contaminating the soil in water. Furthermore can then bacteria that grow in the slurried suspension on the settle large surface of the solids and biodegrade the pollutants there. When treated with chemicals added to the aqueous suspension, the large solid surface offers a good attack for the chemicals.

Also for the treatment of waste water is the production of a fine suspension or Emulsion beneficial. So z. B. Fat is more accessible to biodegradation made by breaking it down into fine droplets. The bacteria that accomplish biodegradation are usually in the form of flakes, that can be up to one millimeter and larger. To be dismantled To be able to do so, the pollutants must first penetrate into the flakes and then the breakdown products escape from them again. These operations take place through diffusion and are often speed-limiting for biodegradation. It is known that the biodegradation activity can be increased significantly, when the bacterial flakes break up into smaller units or individual bacteria become.

The present invention has for its object a method and a To provide the device with which a very fine in a simple manner Suspension or emulsion can be generated. In particular, their delicacy is said to be very be even.

The object is achieved in that the liquid in one formed between a rotor arranged in the inner container and a stator Gap is subjected to shear forces, with the stator passing through at least one section the bottom and / or lower wall area of the inner container is formed, and that the liquid through the rotor from the bottom area of the inner container through in the stator existing openings in the bottom area of the outer container  is driven.

The invention relates to an outer container and one located therein Inner container, the liquid to be treated in a circuit between the Inner container and the outer container flows. The liquid flows from the bottom Area of the inner container in the lower area of the outer container and flows back from the top of the outer container to the top of the inner container ters.

According to the invention, the liquid flows through one arranged in the inner container Rotor and a stator through at least sections of the bottom and / or lower Wall area of the inner container is formed. Between the rotor and the stator the liquid is exposed to shear forces, with the help of which particles or drops become fine be divided. The stator has openings. By the action of the rotor the liquid from the gap through the openings in the stator in driven the bottom area of the outer container. Thus, a circulatory flow of the Liquid generated through the rotor-stator arrangement. Every time pour this arrangement, the liquid is subjected to shear forces. The cycle flow ensures that each particle or drop with sufficient Ver most likely because of the liquid in the procedural system speed at least once through the rotor-stator arrangement. Thereby it is achieved that the particles or droplets of the suspension or emulsion very become evenly fine.

According to a preferred embodiment of the invention it is provided that the liquid ventilated at the same time. This is preferably done in that air from the rotor the liquid is hammered in.

The shear stress in the gap between the rotor and stator does not only Solid particles and drops, but also air bubbles very finely divided. As a result of oxygen is therefore a very large phase interface between air and liquid transition from air to liquid is particularly good.  

A rotating movement of the rotor is preferably carried out in the inner container Creates liquid, causing a trumpet to form on the surface of the liquid, which with sufficient strength of the rotational movement down to the rotor extends. The rotor then sucks air through the trumpet and knocks it into the Liquid. So a very good ventilation of the liquid is achieved without it this requires a special device.

According to a special embodiment of the invention is also in the outer container generates a movement of the liquid rotating about the vertical container axis. If the liquid is already rotating from the outer container into the inner container, so this supports the formation of the trumpet.

A special embodiment of the invention provides that the liquid after Flow through the openings in the stator in a further gap between the Stator and another rotor arrives and exposed to shear forces there and by the another rotor is thrown tangentially outwards. This will do two things reached:

For one thing, the liquid becomes twice one each time it passes through the stator Exposed to shear stress, namely in a gap in front of the stator and one another gap after the stator. On the other hand, the liquid from the second rotor flung tangentially outwards into the outer container so that there is a rotation flow is generated.

In order to generate sufficient shear forces between the rotor and stator, it is proposed that the speed gradient in the gap between the rotor and stator be between 10,000 and 100,000 s ^-1 .

According to the invention it is further proposed that solids, the liquid be added, poured into the trumpet, so that the solids free of lumps dispersed and immediately drawn into the rotor. With solids it can are contaminated soil material or chemicals that are used for the Processing can be added.  

By pouring solids onto a moving liquid surface, as it is in the trumpet, solid clumps are prevented from forming. The solids are advantageously drawn into and from the rotor mixed intensively with the liquid.

The device according to the invention is characterized in that within the Inner container a rotor blade having a rotor is arranged that the rotor blades beabstan from the wall area and / or floor area through a shear-effective gap det and that the wall area and / or floor area can be flowed through has refractions.

In this device, the liquid flows down inside the inner container to the rotor, becomes in the gap between the rotor blades and the openings having wall area and / or floor area of a shear stress sets, is driven through the openings into the outer container, flows in this upwards and from its upper area into the upper area of the inside container back.

Thus, the device is suitable for circulating the liquid through the Generate rotor. In particular, the wall of the inner container can have an upper one have a running edge below the liquid level in the outer container is located. The liquid can flow from the outer container over this edge into the Flow back the inner container. The inner container is preferably adjustable in height arranged opposite the outer container. This can change the position of the top circumferential edge can be changed.

It has been shown that the upper peripheral edge of the inner container is also very wide can be located below the liquid level. In extreme cases, the inner container ter only from the perforated wall and floor area.

According to an embodiment of the device are between the inner container and the outside Container arranged a baffles generating a rotational flow, the surfaces form an angle between 30 and 60 ° to the vertical. These baffles guide the  Upward flow in the outer container into a rotating movement. The already in External container rotating fluid maintains its rotational movement when it moves over the upper peripheral edge enters the inner container, so that the formation of a Trompe is supported in the inner container.

The drain from the outer container can be a height-adjustable overflow. This is used to change the liquid level in the outer container. So this can can be adjusted to match the upper circumferential edge of the inner container.

According to a particularly advantageous embodiment of the invention is another Rotor with rotor blades arranged below the bottom area of the inner container and between the rotor blades and the bottom area is another more effective shear Gap present. Of course, it is advantageous if this additional rotor on the same shaft is arranged as the rotor in the inner container. By this arrangement further rotor is achieved that the liquid both before and after Flow through the perforations in the floor area by one shear-effective Gap reached. This increases the shear effect. The one under the floor area located further rotor throws the liquid tangentially outwards into the Outer container and generates a rotational flow.

The ratio of the liquid volumes in the outer container and in the inner container lies preferably between 1: 1 and 10: 1, in particular between 1.5: 1 and 3: 1. In particular then, if the liquid is to remain in the device for a long time, one is sufficient en The relationship can also have time for chemical and biological reactions be chosen larger.

The openings in the wall area and / or floor area of the inner container have the shape of holes or slots, preferably with an opening width between 10 and 30 mm.

The gaps formed between the rotors and the wall area or floor area preferably have a gap between 1 and 10 mm, in particular between 1 and 5 mm.  

The peripheral speed of the rotor blades is in particular between 12 and 60 m / s.

The energy input by the rotor in the inner container, based on the volume of the inner container, is preferably between 3 and 15 kW / m ³ .

It is particularly advantageous if several similar devices with each other can be combined, preferably by series connection. This results in an improved residence time distribution, which is beneficial for the uniformity of the suspensions sion of the emulsion works. In particular, this can cause undesirable short circuits reduce flows from inlet to outlet.

Further details, advantages and features of the invention do not only result from the claims, the features to be extracted from them - for themselves and / or in Combination, but also from the following description of one of the drawings to be taken preferred embodiment.

The only figure shows a vertical section through the preparation device of liquid. The device is along the vertical axis of rotation cut.

A cylindrical outer container ( 20 ), which has a conical bottom ( 22 ), has an inflow ( 24 ) for liquid and an outflow ( 26 ). An inner container ( 28 ) is arranged coaxially to the outer container ( 20 ). Its wall is cylindrical at the top. Below a conical transition, not specified, there is a cylindrical lower wall area ( 30 ) and a floor area ( 32 ). This lower wall area ( 30 ) could also be conical. In the exemplary embodiment, both the lower wall area ( 30 ) and the bottom area ( 32 ) of the inner container have openings ( 34 ). However, it would be possible for only the wall area ( 30 ), or parts of it, to be provided with openings ( 34 ). Likewise, it would be possible that only the bottom area ( 32 ), or parts of it, is provided with openings.

The ratio of the volumes for the liquid in the outer container ( 20 ) and inner container ( 28 ) is preferably between 1: 1 and 10: 1, preferably between 1.5: 1 and 3: 1. Thus, the ratio of the diameters is Containers between about 1.3: 1 and 4: 1, preferably between 1.5: 1 and 2: 1.

The openings can be in the form of holes or slots, with slots in the wall area ( 30 ) preferably being vertical and in the floor area ( 32 ) preferably radial. The opening width of the openings can be 10 to 30 mm, but can also be smaller or larger, depending on the type and property of the suspension or emulsion to be prepared.

In the inner container ( 28 ) is arranged by a motor ( 36 ) via a shaft ( 38 ) driven rotor ( 40 ). The rotor blades ( 42 ) are spaced from the sections of the wall area ( 30 ) and the bottom area ( 32 ), which are provided with openings ( 34 ), by a gap ( 44 ). When the rotor is driven, a shear flow is generated in the gap ( 44 ). Particles or drops that get into the gap ( 44 ) with the liquid are broken up by the shear forces.

Between the rotor blades ( 42 ), the liquid is moved in a circle around the rotor axis and centrifugally thrown outwards. It flows through the openings ( 34 ) and thus passes from the inner container ( 28 ) into the outer container ( 20 ).

The rotor blades ( 42 ) of the rotor can be simple plates which are arranged symmetrically to the shaft ( 38 ), wherein several such plates can be arranged on the shaft so that they each form an angle with one another. The rotor blades ( 42 ) can, however, also be designed in the form of a propeller, so that they produce a downward flow. Of course, other embodiments for the rotor blades ( 42 ) are also conceivable, the two extreme flow forms on the one hand the purely axial flow downwards and on the other hand the purely radial flow outwards.

The direction of flow of the liquid is symbolized by arrows in the picture. In the lower area of the outer container ( 20 ) it is initially directed outwards and is then deflected upwards. In the inner container ( 28 ) it is directed downwards towards the rotor ( 40 ).

In the exemplary embodiment shown, the wall of the inner container ( 28 ) has an upper edge ( 46 ) which lies just below the liquid level in the outer container ( 20 ). In an extreme case, the inner container ( 28 ) can also end at the top of the rotor blades ( 42 ), in contrast to the illustration. Then the edge ( 46 ) lies far below the liquid level. Its height is defined by the position of the drain ( 26 ). This has the shape of an overflow that is adjustable in height. The overflow is preferably connected to a drain pipe, not specified, via a flexible hose, not specified.

The inner container ( 28 ) can be arranged such that it can be adjusted in height relative to the outer container ( 20 ), so that the position of the upper circumferential edge ( 46 ) below the liquid level in the outer container ( 20 ) can be changed.

Baffles ( 48 ) are arranged between the inner container ( 28 ) and the outer container ( 20 ), by means of which the upward flow in the outer container ( 20 ) is set in rotation. The baffles ( 48 ) can also serve as static connecting elements between the outer container ( 20 ) and the inner container ( 28 ). The guide plates ( 48 ) have surfaces which are inclined at 30 to 60 ° with respect to the vertical. The baffles ( 48 ) can be flat or curved sheets. In the second case the angle between the normal on the surface and the vertical becomes smaller towards the top. In particular, the guide plates ( 48 ) can also be twisted. Their size and number is preferably chosen so that there is no longer any vertical line between them. Baffles ( 48 ) can be arranged at different heights. Several layers of baffles ( 48 ) can also be arranged one above the other. The rotational flow in the outer container ( 20 ) generated by the guide plates ( 48 ) expediently has the same direction of rotation as the rotor ( 40 ). Liquid flowing upwards in the outer container ( 20 ) is set into a rotary movement by the guide plates ( 48 ), which it maintains when it flows over the upper peripheral edge ( 46 ) of the inner container ( 28 ) into the latter and there to the rotor ( 40 ) is pulled downwards so that a trumpet forms in the inner container ( 28 ), which preferably extends down to the rotor ( 40 ). Such a trumpet is shown in the figure. Through this trumpet, the rotor ( 40 ) sucks in air, mixes it with the liquid, shears it into fine bubbles in the gap ( 44 ) and presses the bubbles together with the liquid through the openings ( 34 ) into the bottom area of the outer container ( 20 ).

In the embodiment shown, a further rotor ( 50 ) is arranged on the shaft ( 38 ) below the bottom area ( 32 ) of the inner container ( 28 ). This has rotor blades ( 52 ) which form a gap ( 54 ) with the bottom region ( 32 ). The liquid passes from the rotor ( 40 ) through a gap ( 44 ) through openings ( 34 ) in the bottom region ( 32 ) into the further gap ( 54 ) and is winged ( 52 ) by the rotor tangentially outwards to the bottom region of the outer container ( 20 ) hurled.

The gaps ( 44 , 54 ) have a gap width of preferably 1 to 10 mm, in particular 1 to 5 mm. With a circumferential speed of the rotor blades ( 45 , 52 ) between 12 and 60 m / s, speed gradients can be calculated in the columns from 1,200 to 60,000 s ^-1 .

Without a license plate, an emptying option for the outer container ( 20 ) is shown in the form of a tube with a slide starting from the lowest point of the bottom ( 22 ) of the outer container ( 20 ).

The arrow ( 56 ) shows the preferred addition point for the solids to be added. These are poured into the trumpet.

Claims (22)

1. A method for treating liquid such as contaminated soil material and / or sewage slurried in water by producing a fine suspension or emulsion, the liquid flowing in the circuit from the bottom region of at least one inner container arranged in an outer container to the bottom region of the outer container and from the upper region of the Outer container back into the upper region of the inner container, characterized in that the liquid is exposed to shear forces in a gap formed between a rotor arranged in the inner container and a stator, the stator being formed by at least a portion of the bottom and / or lower wall region of the inner container, and that the liquid is driven through the rotor from the bottom region of the inner container through openings in the stator into the bottom region of the outer container. 2. The method according to claim 1, characterized, that the liquid is aerated at the same time. 3. The method according to claim 2, characterized, that air is hammered into the liquid by the rotor. 4. The method according to claim 3, characterized, that by the rotating movement of the liquid in the inner container up to trumpet extending to the rotor is formed. 5. The method according to claim 4, characterized, that the liquid in the outer container in a around the vertical axis of the container rotating movement is offset. 6. The method according to any one of the preceding claims, characterized, that the liquid after flowing through the openings in the stator in one reached another gap between the stator and another rotor and there Is exposed to shear forces and from the further rotor tangentially to the outside is thrown. 7. The method according to any one of the preceding claims, characterized in that the speed gradient in the gap between the rotor and stator is between 10,000 and 100,000 s ^-1 . 8. The method according to any one of the preceding claims, characterized, that solids to be added, such as. B. Soil material in a itself in the inner container  ter forming trumpet are poured so that the solids free of lumps dispersed and immediately drawn into the rotor. 9. The device, in particular for carrying out the method according to claim 1, consisting of a preferably cylindrical outer container ( 20 ) with a preferably conical bottom ( 22 ) and an inner container ( 28 ) arranged in the outer container ( 20 ), which in the cylinder or conical lower wall region ( 30 ) and / or bottom area ( 32 ) for liquid flowing to the outer container ( 20 ) and open at the top for liquid flowing back from the outer container ( 20 ), characterized in that
that a rotor blade ( 42 ) having a rotor ( 40 ) is arranged within the inner container ( 28 ), that the rotor blades ( 42 ) are spaced from the wall area ( 30 ) and / or floor area ( 32 ) by a shear-effective gap ( 44 ) and
that the wall area ( 30 ) and / or floor area ( 32 ) has through-openings ( 34 ). 10. The device according to claim 9, characterized in that the wall of the inner container ( 28 ) has an upper peripheral edge ( 46 ) which is located below the liquid level in the outer container ( 20 ). 11. The device according to claim 10, characterized in that the inner container ( 28 ) is arranged adjustable in height relative to the outer container. 12. Device according to one of the preceding claims, characterized in that between the inner container ( 28 ) and outer container ( 20 ) a rotating flow generating baffles ( 48 ) are arranged, the surfaces of which form an angle between 30 ° and 60 ° to the vertical. 13. Device according to one of the preceding claims, characterized in that the outlet ( 26 ) from the outer container ( 20 ) is a height-adjustable overflow. 14. Device according to one of the preceding claims, characterized in that a further rotor ( 50 ) with rotor blades ( 52 ) is arranged below the bottom region ( 32 ) of the inner container ( 28 ), and that between the rotor blades ( 52 ) and the bottom region ( 32 ) there is a further shear-effective gap ( 54 ). 15. Device according to one of the preceding claims, characterized in that the ratio of the liquid volumes in the outer container ( 20 ) and inner container ( 28 ) is between 1: 1 and 10: 1. 16. The apparatus of claim 15, characterized, that the ratio is between 1.5: 1 and 3: 1. 17. Device according to one of the preceding claims, characterized in that the openings ( 34 ) are holes or slots with an opening width between 10 and 30 mm. 18. Device according to one of the preceding claims, characterized in that the gap ( 44 ) and the gap ( 54 ) has a width between 1 and 10 mm. 19. The apparatus according to claim 18, characterized in that the gaps ( 44 , 54 ) have a width of 1 to 5 mm. 20. Device according to one of the preceding claims, characterized in that the peripheral speed of the rotor blades ( 42 , 52 ) is between 12 and 60 m / s. 21. Device according to one of the preceding claims, characterized in that the energy input through the rotor ( 40 ) to the volume of the inner container ( 28 ) is between 3 and 15 kW / m ³ . 22. Device of the method according to one of the preceding claims, characterized, that several similar devices can be combined, preferably wise through series connection.