FI113629B - Process and plant for carrying out physical and chemical processes - Google Patents

Description

113629

Method and apparatus for performing physical and chemical processes

The present invention relates to a process according to the preamble of claim 1 for performing physical and / or chemical processes in a percussion mixer.

According to such a method, the processes are carried out in a fluid state with a combination of devices consisting of a multi-rotor assembly and external devices.

The invention also relates to an apparatus according to the preamble of claim 7.

10 impact mixers have been used e.g. for solids removal, chemical processing of solid, liquid and gaseous materials, sludge drying and gas scrubbing. Impact mixers may be provided with two or more rotating rotor rings. Examples of prior art solutions include the devices disclosed in F1 1571588 and F1 9439914 and US 5,813,758, CH 372 537 and GB 783 712.

In typical current multi-rotor mixers, the powder comes from a screw or belt dispenser and is sprayed with water before being introduced into the mixer. The first impellers of the rotor mixer disintegrate the powder coats, after which mixing begins.

20

There are significant drawbacks to known solutions. Thus, the current rotor mixer has a housing with a discharge opening around the rotor. The clearance between the housing and the outer rotor is only 2 to 10 mm, which causes friction, especially with dilute substances. The proportion of friction may have increased the power requirement by up to 50%.

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In the discharge orifice rotor mixer, the particles have a different residence time and treatment, depending on whether the particle has come out of the outermost rotor periphery at or just after the discharge is required to remain in the housing under high shear during rotor rotation.

: 30 '' The spacing between the wings of the rotating blades, about 40 to 50 mm, is 2 to 3 mm, whereby: the blade leaving end acts only as a film maker about a distance of about 20 mm. Wing front: Not substantially involved in the whole mixing event.

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As stated above, the devices have been used for chemical processing, for example carbonation.

When carbonating calcium hydroxide in a fluid in a rotor mixer or mixer compound, the disadvantage is that the fluid is mainly converted into slurry on the outer periphery of the mixing chamber before it can exit the peripheral outlet. Similarly, the particles to be treated stay in the mixing state for different lengths of time. The delay difference varies up to 70% depending on whether the particle reaches the outlet directly from the outermost wing or has to rotate the entire circumference of the mixing chamber.

10

It is an object of the present invention to overcome the drawbacks of the prior art and to provide a completely novel solution for carrying out physical and / or chemical processes in a blow mixer.

The invention is based on the idea that the product, powder or slurry to be processed is treated, in addition to the cyclic fluid in the rotor space, in the discharge and / or inlet side of the fluid space. The processor powder is introduced into the mixing section of the multi-rotor space as a fluid and sprayed with a liquid.

The apparatus utilizes a multi-rotor mechanism with the housing immediately surrounding the rotors at least partially, preferably completely, removed. In this case, the material introduced into the mixer can be removed from the periphery of the mixer at many points or preferably from the entire circumference. Removal is continuous and every part of the material is treated in the same way. The appliance then acts as a kind of spray dryer with wings. The solution makes the product quite homogeneous.

More precisely, the method according to the invention is essentially characterized by what is stated in the characterizing part of claim 1.

The apparatus according to the invention, in turn, is characterized by what is stated in the characterizing part of claim 7.

The present invention achieves considerable advantages. Thus, the method removes · · ** these disadvantages and provides a more efficient carbonation result when calcium hydroxide,. water and CO 2 fluid continue the reaction in the outer space and under the effect of the reaction heat generated: · 35 partially evaporates and decomposes the droplets, increasing the reaction area. In addition, the process according to the invention enables a greater circulation of carbon dioxide in the rotor system as well as the supply of additional gas as a control gas, which speeds up the reaction since additional carbon dioxide is used to displace the water vapor generated in the process.

In the impeller design of the invention, the impeller blades are narrowed to an effective width of, e.g., about 20 mm (i.e., about half that of conventional mixers) and the blade spacing is about 10 to 20 mm. Between the wings, turbulence can occur, which, by means of atrophy, breaks down the powder clumps. As a result, the homogeneity of the product to be mixed and the need for power is reduced by about 10-20% 10

Briefly, the following advantages of the invention may be summarized: 1. Maintaining the fluid state during transfer, processing, and post-processing allows for more complete processing.

2. Removal of the processed product from the outer periphery over the entire circumference gives a more homogeneous product because the process time at the particle level is nearly the same.

3.The removal of the processed product over the entire circumference of the outermost rotor allows high material flows with less energy consumption than conventional outlet open mixers.

4. In the exothermic reaction, the continuation of the process after the rotor treatment decomposes the droplets in the fluid gas by the resulting vapor pressure and allows the reaction between the fluid gas and the particles to continue.

5. The solids content of the material to be processed can be controlled within a relatively large range of temperature, amount and time of operation of the fluid gas and the jet gas.

: '· 25 6.The process can easily be performed under reduced pressure or overpressure, if necessary.

7.Dusting sometimes occurring in conventional mixers is eliminated as the slurry is discharged from the outermost rotor ring to an external space containing water mist.

"· 8.The lower part of the external space can be used to replace the separate after-mixer tank used on the Net.

: 9.The power requirement of the rotor system is reduced as the friction between the rotor housing and the outermost rotor 30 is removed.

10. Limiting the rotor blade width to the theoretical width and increasing the blade spacing to increase the turbulence rate reduces the need for power.

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11 The sound insulation caused by multi-rotor equipment has been extremely difficult, in the construction of the invention it is simple because the mixing takes place well in a closed state.

I * · »I · ·,» · • · 113629 4 12. It is possible to increase or decrease the number of successive rotors when the rotor housing does not limit the diameter change.

13. The powder introduced in the fluid can be added evenly to the ready slurry.

14. Dispersants are long chain polymers and are readily cleaved upon vigorous handling of the rotors 5, now the dispersant can be introduced into the control gas by spraying into the fluid coming from the rotor.

15. The pneumatic powder transfer associated with the invention allows free placement of the mixer, e.g. in a slurry, where previously placement has been limited by screw-belt and other mechanical feeders. In some cases, the mixer may be mounted directly on the top of the storage tank.

16. The pneumatic powder transfer associated with the invention enhances agitation because the transport breaks the lumps in the powder already during transport, as they would otherwise only disintegrate on the first rings, and the fluid transport facilitates water delivery and uniform distribution within the powder prior to rotor mixing.

15 17.The rotor shaft can be horizontal or vertical or any intermediate depending on the application. The pneumatic powder transfer associated with the invention enables the rotor to operate in a free operating position, e.g.

18. Fluid imported powder does not cause water splashing in spray area resulting in smudging and clogging of feed space.

20 19.Sealing problems are removed between the rotor and the housing.

20.Simple construction, especially as a rotor / stator structure

The invention will now be further explored by means of a detailed description with reference to the accompanying drawings.

Fig. 1 is a sectional side elevational view of a mixing device according to the invention. Fig. 2 is a sectional side elevational view of a preferred embodiment of a blow mixer according to the invention: - Fig. 3a shows the reaction of the fluid obtained from the blades of the mixer, Fig. 3b is a detail of the previous figure,

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Fig. 4 is a sectional side elevational view of another embodiment of a mixing apparatus according to the invention, differing from the structure shown in Fig. 1 in that the bottom of the container is conical; Figs. Fig. 6 is a cross-sectional side view of a third embodiment of a mixing apparatus according to the first embodiment of the invention, comprising a dry powder feed apparatus and separate feed channels for different substances (gases, liquids and solids); which differs essentially from the structure shown in Figure 1 in that the substances to be mixed are fed from above to the mixer.

10 The following reference numerals are used in the drawings.

IFIid Transmission Equipment 1.1 Pneumatic Transmission 1.2 Transmission Gas Temperature Control 15 1.3 Fluid Gas and Powder Adjustment 1.4 Powder Additive Dispensing 1.5 Powder Adjustment 2. Multi Rotor Assembly 20 2.1 Rotor Hoops 2.2 Rotor Wing 2.3 Powder Inlet Mode 4. Power Transmission Mode 3. Rotary Power Control 3. Rotor Power Mode 3. Rotor Wing Mode removal 7. Powder removal 8. Container 30 ♦. The device assembly of the present invention comprises a multi-rotor assembly 2 housed in a container 8. The multi-rotor assembly 2 and its peripherals form a multi-rotor assembly. The combination enables the use of the fluid mode in all multi-rotor equipment. Multiple | *. ·. rotors 2.1, 2.2 of the rotor assembly have a cyclic fluid-film space and an outer rotor ·. Outside 35 there is a free fluid space.

··, Unlike known mixers, the present machine does not have a housing that surrounds Λ t · ··. roottoristoa. In conventional impact mixers, the inner wall of the mixer is located about 1 - i t · *, 10 mm from the outer edge of the outermost mixer ring. The outlet wall is then provided with a · · 40 outlet. The device according to the invention does not have outlet openings per se (however, the invention can also be implemented using a housing structure having a plurality of I 1 · 113629 6 outlet openings evenly distributed around the periphery of the housing wall). The machine is surrounded by a tank 8, the inner wall of which, however, is so far away from the rotors that the gas flow described below can prevent the treated material from striking the wall. Typically, the distance between the inner wall of the container and the outer periphery of the rotors is at least 50 mm, preferably at least 100 mm.

The distances of the rotor blades 2.1 in the radial direction are 0.1-5 mm and those of the blades 2.2 in the radial direction 10-40 mm.

The rotors generally have a rotational speed of about 100 to 10,000 rpm, preferably about 500 to 5,000 rpm, and a peripheral speed of at least about 50 m / s. There is excess pressure inside the system. It is preferably from about 2 to about 50 bar, preferably from about 5 to about 20 bar, typically about 10 bar. The outlet velocity of the material is about 10-500 m / s, typically about 20-300 m / s, preferably about 30-150 m / s.

15

In the space between the blades of the multi-rotor assembly, turbulence is created and a film is formed on the surface of the blades, as shown in Figure 3A.

At the material inlet 2.3, a fluid is formed containing the materials to be processed in the multi-rotor assembly 20. In this space, the slurry to be processed can be atomized into a fluid gas or fluid containing powder. It is also possible to bring powder, water and gas into the inlet space (see Figure 5). To the multi-rotor mixing section I ·. the fluid gas to be introduced may e.g. be involved in the process either chemically or by heat.

· ": 25 The product, powder or slurry to be processed may be treated in addition to the cyclic fluid in the rotor space on the outlet and / or inlet fluid space.

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The cyclic fluid-film space is formed in the rotor frames and the fluid space extends outside the outer rotor (see Figure 3A). From the mixing section, the fluid moves into the cyclic fluid film 30 of the rotors, and finally out of the fluid state over the entire circumference of the outer rotor.

,: The rotors of the machine are preferably arranged to rotate about a substantially vertical axis in the horizontal plane. However, the actuator may be rotated such that: the central axis of the rotors forms a desired angle, e.g., from 1 to 99 degrees, with the vertical plane.

35 113629 7

According to a preferred embodiment of the invention, in which the central axis is perpendicular to the vertical plane, the feed materials can be introduced into the mixer from below. However, it is possible to feed them from above in a manner known per se.

5 A jet of control gas 4 is directed from the outermost peripheral jet of the multi-rotor unit to the jet which guides the jet. For example, air or nitrogen or some other inert gas may be used as the gas. Preferably, the jet to which the control gas is directed decomposes according to the particle droplet size, and the jet is distributed by droplet separator 5. The control gas may contain process agents or the process gas temperature or relative humidity will influence the process flow.

The apparatus described above can be used in such a way that the internal pressure of the apparatus differs from the external pressure.

15 Fluid gas is removed in the vicinity of the slurry surface. The powder product and the fluid gas are preferably removed to the cyclone and the powder separator. These are not shown separately in the figures.

Examples of the use of the invention 20

Lime slaking in the processor according to the equation Ca0 + H, 0 → Ca (OH).

The pre-ground calcium oxide is introduced into the gas as a mixed fluid in a multi-rotor processing: an inlet of the apparatus where water is injected into the fluid. In the rotors, a film is formed on the surface of the wings * and a drop is formed on the trailing edge of the wing at the bulwark between the blades, repeating as many times as there are blades. The calcium oxide slurry, which has already largely reacted from the outermost rotor, continues the reaction in the post-fluid state. The jet control *. * Gas contains mist water and possibly dispersants and other additives. Conversion of mist * 30 to steam effectively removes process heat. The vapor is carried away with the fluid gas.

* · »$ - i · ', The process described below yields very finely divided calcium hydroxide> 10; hydroxide.

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After processing, the resulting calcium hydroxide is allowed to stand in the tank for some time to react with the covalent bond portion of the reaction.

Carbonization in the processor according to the equation CaO + HX) -> Ca (OH) ·, + CO, -> CaCQ, + 5 H, 0

Calcium hydroxide is pumped through the atomizer nozzle to the inlet of the processor, where CO2 is mixed with the mist. The CO 2 gas, or a portion thereof, may also be introduced through 10 calcium hydroxide nozzles to enhance spraying. In the rotors, a film is formed on the surface of the wings, and a droplet is formed on the blade leaving edge in the turbulence between the blades, repeating as many times as there are blades. The calcium hydroxide-containing foggy slurry, which has already largely reacted from the outer rotor, continues the reaction in the post-fluid state.

15

The jet control gas, which is CO 2, contains mist water and possibly dispersants and other additives.

The fully or nearly completely reacted calcium hydroxide-containing slurry is directed by means of a jet control-20 gas to the bottom of the tank from which the slurry is pumped for further treatment or storage.

Drying sludge in the processing unit:, The sludge to be dried is introduced by pumping into the mixing space in the part before the rotors and spraying with hot gas around the jet.

• »· * * • *. The rotor blades grow towards the outer periphery and the sludge fish / · ·, respectively, sealing on the wing surface. The volume of the slurry flung out of the last circumference reaches into droplets the size of which depends on the film thickness. The film thickness depends on the blade and the surface forces of the slurry. Visit ···. The 30 practical limit can be considered as 10 to 30 pm after which the film begins to taper. my main Tainos.

* · # The control gas stream continues the drying process and the slurry changes to a powder form.

M * '* · * If you wish to remove large droplets that form large powdery aggregates: 35 droplet classification is used for control gas.

113629 9

The amount of gas and the temperature are determined in relation to the dry matter content of the slurry to be dried.

The heat of evaporation of the water evaporated from the sludge lowers the temperature and thus avoids the temperature rise of the rotor 5 above 100 ° C.

Heat from the mixing and possible exothermic reaction can be utilized in the drying process.

Example 1

Use of external rotor space for carbonation.

Equipment: 1. 2-rotor mixer, external rotor diameter 300 mm 15 2. Container, 1500 mm diameter height 1700 mm 3. Rotor casing, diameter 420 mm 4. Feeders for Ca (OH) 2 and CO 2

Experimental Arrangement: 20 The mixer was mounted inside the top of the tank with the inlet side down. In the basic experiment, there was a sheath around the rotor which was removed in the comparative experiment. Otherwise the test feed and other settings were the same in both experiments. For the experiment, CaO was quenched to give the same Ca (OH) 2 for both experiments. In both experiments, carbonated Ca (OH) 2 was initially pumped out 10 min before sampling to reach operating temperature.

,, Measurement results of the basic test:

Ca (OH) 2: dry matter content 16.2% 30 Ca (OH) 2 carbonate content 7% s 1

Heat of Ca (OH) 2 before carbonation 64 ° C Heat of Ca (OH) 2 after carbonation 45 ° C '·· 1 Ca (OH) 2 carbonate content after carbonation 39% i · I t ·:: 35 Comparison test results: teaspoon · ·· • · 113629 10

Ca (OH) 2: 16.2% solids

Carbonate content of Ca (OH) 2 7%

Heat of Ca (OH) 2 before carbonization at 60 ° C 5 Heat of Ca (OH) 2 after carbonization at 50 ° C

Carbonate content of Ca (OH) 2 after carbonation 74%

As can be seen from the above information, the invention provides a much more efficient carbonation. 1 h I ·

Claims (20)

A method for carrying out physical and / or chemical processes in fluid state by means of a device combination comprising a multi-rotor device (2) arranged with two or more rotors (2.1, 2.2) forming a rotor compartment, characterized by a device combination (8). a product, a powder or sludge to be processed, except in a cyclic fluid state formed in the rotor chamber, also on the outlet and / or inlet side (3, 2.3) in fluid state, and 10. the powder to be processed is supplied the mixing portion (2.3) of the multi-rotor compartment in fluid form and sprayed with liquid. 2. A method according to claim 1, characterized in that the sludge to be processed is fed to the mixing portion (2.3) of the multi-rotor compartment and injected into fluid gas supplied to the same compartment. Method according to claim 1 or 2, characterized in that the fluid gas to be supplied to the mixing portion (2.3) of the multirotor space participates in the process either chemically or by means of heat. 20 Method according to any of claims 1-3, characterized in that the fluid is transferred from the mixing portion (2.3) of the multi-rotor compartment to a cyclic fluid film condition at the rotors, and finally out in fluid state over the entire periphery of the outer rotor. 1 ·; I 25 5. A method according to any one of claims 1-4, characterized in that the fluid which sprays from the rotor space (2.1, 2.2) is directed and / or processed in the tangential direction. by means of an external gas or gas fog jet. Process according to claims 1-5, characterized in that the product, the sludge *. Or the powder being processed is separated from the fluid gas. »» <»♦ 7. Apparatus for performing physical and / or chemical processes; * * comprises a multi-rotor device (2) arranged in a container (8) having two or more rotors in * v,: (2.1.2.2) forming a rotor compartment, a fluid state being formed in multi-rotor devices: The process for carrying out the processes, characterized in that the rotors (2.1, 2.2) of the multi-rotor device 113629 are arranged to form a cyclic fluid film state and beyond the periphery of the outermost rotor (2.2) a free fluid state arises. Multirotor device according to claim 7, characterized in that a fluid containing the substances to be processed in the multirotor device can be formed in the entrance space (2.3) of the material. A multi-rotor device according to claim 7 or 8, characterized in that the spacing of the rotor blade peripheries (2.1, 2.2) in the radial direction is up to 0.1-5 mm and the distance of the wings in the radial direction to 10-40 mm. Multirotor device according to any of claims 7-9, characterized in that in the space between the wings of the multirotor device (2.1,2.2) turbulence can be formed and on the surface of the wings a film. Multirotor device according to any of claims 7-10, characterized in that in the entrance room (2.3) of the multirotor device, one or more nozzles are connected for injecting water and / or additives into the fluid entering the powder. Multirotor device according to any of claims 7-11, characterized in that a nozzle is connected to the sludge entrance of the multirotor device (2.3) to inject the sludge; 'to be processed, in the fluid gas or fluid containing powder. Multi-rotor device according to any of claims 7-12, characterized in that, in the entrance space (2.3) of the multi-rotor device, powder, water and gas can be supplied via inlet pipes and a cyclic fluid film state can be formed in the rotor peripheries and the fluid state continues outside (3). outermost rotor. Multirotor device according to any of claims 7-13, characterized in that in the jet from the outermost periphery of the multirotor device, a control gas jet (4) can be directed. 15. Multi-rotor device according to any of claims 7 - 14, characterized in that ...: the jet coming from the multi-rotor device, to which the control gas is directed,: V: decomposes according to particle droplet size and the jet can be divided by a droplet separator. 113629 16. A multi-rotor device according to any of claims 7-15, characterized in that the inlet pipe (4) of the control gas is connected to an inlet nozzle, with which substances can be fed into the gas which affect the process. A multi-rotor device according to any of claims 7-16, characterized in that the inlet pipe (4) of the control gas is connected means for regulating the temperature or relative humidity of the gas, the thread of the process being actuated by the control gas. Multirotor device according to any of claims 7-17, characterized in that the internal pressure of the device differs from the external pressure. Multirotor device according to any of claims 7-18, characterized in that the fluid gas can be removed from the proximity of the mud surface. Multirotor device according to any of claims 7-19, characterized in that the powdery product and the fluid gas can be removed via an outlet tube for a cyclone and a powder separator. »» • <t 1 «« 1 «•» • I • I <# · ♦ · • »I tt 0 • II1 • 1» • • · (> I »• •• Il • ·« tt • I • · t III f> «• t» IIIII • I • »I» »