JPS5825481B2 - Method and apparatus for drying or concentrating suspensions or solutions - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for drying or concentrating suspensions or solutions.

More particularly, the present invention involves applying a liquid, which is a suspension or solution of one solid, to the surface of a number of carriers, which can be spheres or polyhedra, to wet the carriers and extracting some or all of the moisture from the liquid. A gas, such as hot air, is blown through the bed of the wetted support so as to evaporate and leave a thin film or layer of dry or substantially dry solids on the support. The present invention relates to a method and apparatus for the continuous treatment of liquids in which solids are recovered by separating the solids from a carrier which moves down to appear at the bottom of the bed and is then carried to the top of the bed.

Devices of this type have already been used, for example in British patent specification 42.
No. 3,934 and No. 1,265,719.

In the device of specification No. 423,934, the lifting of the carrier for feeding it into the processing chamber is carried out mechanically (e.g. by a packet elevator) and the application of liquid is carried out by preparing the carrier, e.g. by an elevator. separately by discharging into a typical coating device from which the carrier advances into a processing chamber, or by spraying the liquid onto the carrier after the carrier has been conveyed into the processing chamber. It is done.

In the proposal of specification no. 1,265,719, a central screw in the processing chamber serves to lift the carrier through the center of a bed of carriers contained within the processing chamber, and the liquid
It is added to the carrier as it emerges from the top of the screw and joins the bed of carrier in the upper part of the processing chamber.

The object of the invention is that mechanical lifting of the carrier is omitted;
A liquid is used during the process to lift the carrier;
As mentioned above, the two steps involved are thereby combined and simplified, namely the step of wetting the carrier and the step of lifting it, with the result that the efficiency and economy of the method can be improved. An object of the present invention is to provide methods and apparatus configurations.

In relation to the device of specification no. 1,265,719, the present proposal does not require the presence of screws or other mechanical carrier lifting devices in the processing chamber, and therefore compared to earlier proposals. This provides the advantage that increasingly higher temperatures can be used.

With these objects in mind, the present invention involves applying a suspension or solution of one solid to the surface of a number of carriers, wetting the carriers, and depositing a thin or substantially dry film or layer of dry or substantially dry solids on the carriers. The liquid is continuously processed by blowing a gas through a bed of carriers in a processing chamber, as it moves downward through the bed, to cause the evaporation of some or all of the moisture from the liquid, leaving behind a The solids are recovered by separating the solids from the carrier, which appears at the bottom of the bed and is carried to the top of the bed, and the carrier emerges from the bed and separates the solids, through which the carrier is allowed to flow. Proceeding to a liquid application system comprising an upward duct carried by the fluid, the carrier processes the liquid continuously, characterized in that upon reaching the upper end of said duct, the carrier is separated from the liquid and returned to the upper part of the processing chamber. provide a method.

The present invention further provides an apparatus for applying a liquid to the surface of a plurality of carriers to wet the carriers, for containing a bed of carriers, and for leaving a thin film or layer of dry or substantially dry solids on the carriers. a treatment chamber, separated from the carrier moving downward through the bed, with a device for blowing gas through the bed of carrier so as to cause evaporation of some or all of the moisture from the liquid; and a conveying apparatus for conveying the carrier emerging from the bottom of the bed back to the top of the bed, the conveying apparatus comprising: The liquid application system includes an upward duct, a liquid application system that advances after separating the solids.
a device for causing the liquid to flow upwardly therethrough while simultaneously carrying the carrier, and a separating device at the upper end of said duct for separating the carrier from the liquid and returning the carrier to the upper part of the processing chamber. Provided is an apparatus for continuously processing a liquid that is a suspension or solution of one solid.

The invention will be further described by way of example with reference to the attached drawings, in which: FIG.

First, refer to FIG.

The first aspect of the apparatus of the invention is an apparatus for continuously processing a liquid to evaporate water from a liquid, which is a suspension or solution of one solid, leaving a dry or nearly dry solid. One embodiment comprises a cylindrical column or vessel 10 having a substantially vertical axis and defining a processing chamber 11 .

The bottom of the processing chamber 11 is defined by a substantially frustoconical current transformer 12, the open bottom of the current transformer 12 being rotatable, provided at the upper end of a substantially vertical shaft 14. Occupied by a discharge disk 13, a vertical axis 14 extends through a bearing box 15 installed in an oblique discharge space 16 at the bottom of the column or vessel 10.

The shaft 14 is driven by an electric motor 18 via the gear box 11,
A conical central piece 19 is attached to the discharge disc 13 .

The processing chamber 11 is occupied by a bed consisting of several tens of material carriers 20.

These carriers 20 can, for example, be in the form of spheres (for example of ceramic or metallic material) or polyhedrons,
The bottom of this bed is supported by a current transformer 12 and a discharge disk 13.

At a level corresponding to the upper part of the current transformer 12, the gas population space 21 has a gas inlet hole 2 bored in the wall of the tower or vessel 10.
2 surrounding the tower or vessel 10.

This gas inlet space 21 is connected to a source of hot gas, which can be, for example, from a combustion installation or waste gas from other industrial processing plants.

The hot gas is fed to the bed of carrier 20 and the column or vessel 10
The exhaust gas can flow upwardly therein towards the waste gas outlet 23 which connects near the top of the exhaust gas.

A collecting box 25 for excess liquid is arranged centrally in the container 10 below the axially arranged material carrier inlet 24, the upper part of the collecting box 25 being convex when viewed from the side. The bottom of the collection box 25 extends towards the outlet 21 for excess liquid.

The oblique discharge space 16 opens into a solids separator with a chute 28 for receiving solid material.

The tip of the solid material receiving chute 28 lies in an inclined plane in contact with the inclined surface of the space 16 and is covered by a respective perforated plate or mesh lid 29 which is substantially planar and is closed to the overflow edge. Have 30.

The overflow edge 30 is such that when the carrier rolls across the overflow 29, the carrier passes over said edge 30 and into the hopper 3.
It is arranged so that it falls into 1.

The hopper 31 has respective inlets 3 controlled by respective receiving valves 33 for the two carrier receiving vessels 34.
Has 2.

Only one of the carrier receiving vessels 34 is shown in the drawing.

If desired, overflow 29 can be fitted with a device for vibrating it.

A respective butterfly valve 35 is provided at the bottom of each receiving receptacle 34, the arrangement of which will be explained further below, so that when the upper receiving valve 33 of either receptacle 34 is open, the butterfly valve 35 is and vice versa, when the upper receiving valve 33 of one container 34 is opened and the carrier 20 is allowed to fall into said one container 34, the other container 34 upper receiving valve 3
3 is closed or vice versa.

Thus, the two containers 34 are alternately filled and emptied.

When one of the containers 34 is filled with carriers 20 entering from its upper population 32, the discharge of these same carriers 20 at the bottom of the container 34 is prevented by the respective annular valve 35.

However, in the other container 34, the respective inlet 32 is simultaneously closed and the annular valve 35 is opened to allow said other container 34 to be emptied.

An annular valve 35 is arranged at the upper end of each carrier supply duct 36, which converges and joins together with a horizontal lower duct section 31 which connects with an upward duct 38.

The upward duct 38 extends upward to and terminates in a separation vessel 39 at a higher level.

A nozzle 40 provided at the outlet of the pump 41 projects into the horizontal lower duct section 37 .

Pump 41 serves to draw liquid 42 from supply tank 43 through valve 44 and sends the liquid out of nozzle 40 as a jet.

This simultaneously causes the liquid to flow upwards through the upward duct 38 to the separation vessel 39 and also causes a reliable transport of the carrier 20 by the liquid via the supply duct 36 to the lower duct section 31.

As can be seen in the drawing, the upward duct 38 terminates in the separation vessel 39 at an inclined perforated partition plate 45 .

The partition plate 45 has an inclined carrier return duct 46 extending towards and connecting to the carrier inlet 24 of the column or vessel 10.
tilt towards and connect to it.

The lower part of the separation vessel 39 has an outlet 41 that connects to a liquid return pipe 48 .

The liquid return pipe 48 is in turn connected back to the supply tank 43.

The separation vessel 39 can also have a second or alternative outlet 49 which is likewise connected to the supply tank 43 via an inlet 50, as shown in dashed lines in the figure.

Excess liquid outlet 2γ is also connected to supply tank 4 via population 50.
Connected to 3.

The inlet 50 further includes a supply of fresh liquid (not shown).
connected to.

The method of operation of the apparatus will be readily understood from the foregoing.

The hot gas enters the vessel or column 1 via the space chamber 21 and gas inlet holes 22 around the wall of the vessel or column 10.
0 from the bottom.

These gases pass upward through the bed of carrier 20 and are discharged near the top of the column through waste gas outlet 23.

As previously mentioned, these gases can consist of hot air or hot waste gas from some other process.

The waste gas that has reached the outlet 23 has a lower temperature than the temperature at which it entered via the space 21 and contains moisture that has evaporated from the surface of the carrier 20.

The carrier 20, which joins the bed at the top of the bed in the processing chamber 11, has its surface drenched with a liquid in the form of a solution or suspension of the solid that is desired to be recovered.

These carriers 20 are provided with a current transformer 12, a conical central piece 19, and a discharge disc, which are provided to move the carriers downwardly through the process chamber 11 by gravity and through the bed at approximately equal speeds. It passes vertically downward through 13 facilities.

The disk 13 has a number of holes through which the carrier 20 passes, and the arrangement is such that the area of these holes can be adjusted.

Thereby, the rate at which the carrier 20 passes through it and leaves the processing chamber is regulated.

Typical rotational speeds of the disk 13 are from 5 rotations per minute to 20 rotations per minute, but of course a suitable speed is selected to ensure uniform flow of the carrier 20 within the processing chamber.

After passing through the discharge disk 13 , the carriers 20 run over the inclined bottom of the oblique discharge space 16 and from the oblique discharge space 16 onto the lid 29 of the receiving chute 28 .

This lid 29 can be vibrated and the carrier 20
rolls over the lid 29 while the dried solids fall from the surface of the lid through the numerous holes in the lid 29 into the receiving chute 28.

From the receiving chute 28, the dried solids can be sent for further processing or can be bagged.

A feature of this method of discharging the carrier 20 from the bottom of the processing chamber 11 is that, depending on the nature of the liquid material to be treated and the solid contents to be recovered, a portion of the dry solid material on the carrier moves down the bed. However, by the time the carrier passes through the disk 13, it has already been separated from the carrier 20.

The carrier 20, which is in direct contact with the disk 13, rotates with the disk and imparts a rotational movement to the sphere immediately above it.

The resulting relative movement of the carriers 20 rubs the carriers against each other and sheds dried product from their surfaces, also reducing the required efficiency of the subsequent separator constituted by the lid 29.

Once all or a portion of the dried solid material has been separated from the carrier 20 passing over the lid 29, the carrier is wetted or coated with fresh liquid material and the carrier is placed in the upper part of the processing chamber 11. It is necessary to raise the carrier to

As already described, these carriers 20 passing over the lid 29 roll one of the receiving containers 34 into the other.

The arrangement of the receiving container 34 is such that the carrier 20 can be introduced into the liquid in the horizontal duct section against the pressure of the liquid in the ascending duct 38.

The receiving container to be filled has its upper receiving valve 33 opened to allow the carrier 20 to enter.

The other container 34, which already contained a large amount of carrier 20, has its top receiving valve 33 closed and its bottom annular valve 35 opened.

Thus, the carrier 20 is allowed to enter the horizontal duct section 37, while the closed upper receiving valve 33
Prevent loss of liquid from the top of 4.

When the carrier 20 is transferred to the respective receiving container 34, the annular valve 35 at its bottom is closed and the receiving valve 33 at its top is closed.
is opened to allow fresh input of carrier.

Simultaneously with the fresh input of carriers, valves 33 and 35 of the other container 34 are actuated to allow the carriers to enter the horizontal duct section 3γ.

The operation of the valve can be carried out by a pneumatic device under the control of a clock device.

Upon exiting the respective receiving vessel 34, the carriers 20 enter the duct section 31 and are carried into a separation vessel 39 by the liquid pumped into the upward duct 38.

The annular valve 35 allows the velocity of the liquid to move upward through the carrier 20 into the duct 3.
until it exceeds the minimum value needed to carry it above 8.
Allows the speed of the liquid to be adjusted.

For example, with a dilute, cold aqueous solution and a 19 mm diameter ceramic carrier, it is necessary to have a velocity in the upward duct section 38 of greater than about 0.9 meters per second.

Other liquids, solutions, or slurries will have different minimum velocity requirements.

Separation of the carriers 20 from the liquid after being brought to the top of the upward duct 38 takes place in a separation vessel 39 in which the carriers 20 carried by the liquid are transferred to the open upper end of the duct 38. and flows over the partition plate 45 of the separator, which is an inclined perforated plate.

Excess liquid passes through the perforated partition plate 45, flows into the bottom part of the separation vessel 39, and is returned to the supply tank 43 through the return pipe 48.

Depending on the location of the feed tank 43 and the speeds used in this system, it is possible to remove carrying air or gas from the returned liquid and to prevent such air or gas from circulating in the liquid circulation system. For example, it may be necessary to provide one or more screens 51 in the supply tank 43 or use other approved devices.

Fresh liquid is added to the supply tank 43 via inlet 50 as the contents of the supply tank become diluted.

The carrier coated or wetted with the liquid material is supplied to the upper part of the processing chamber 11 via the carrier return duct 46 and the inlet 24 over the perforated partition plate 45 .

The carrier 20 that enters from the inlet 24 is a collecting box 2 for excess liquid.
5, all excess liquid from said carrier passes through the lid 26 and exits the excess liquid outlet 2.
1 and flows back to the supply tank 43.

The carrier 20 itself rolls under the lid 26 and enters the processing chamber 11.

As described, a special feature of the method is that a chute 2 for receiving the carriers 20 is provided for adding the carriers 20 back to the bed.
From 8 onward, lifting of the upper part of the treatment chamber 11 is carried out with the liquid to be treated, thus eliminating the need for a separate coating system located in the upper part of the treatment chamber 11 or outside the vessel or column 10. The reason lies in the fact that

Another important feature of the method is that by adapting the velocity of the liquid through the nozzle 40, it is necessary to provide only one receiving vessel 34, and the receiving vessel 34 is in the open position. Can be used with valves 33 and 35, the conveying effect of nozzle 40 being such that it prevents liquid from flowing back through container 34 and also maintains a column of liquid in upward duct 38. It lies in being a thing.

Alternatively, the supply tank 43 can be placed below the level of the receiving container 34, and if there is sufficient free volume above it, the valve 33.35 may not be provided.

If the nozzle 40 is made of suitable dimensions, for example its throat is approximately half the diameter of the horizontal duct section 37, then there is a suitable liquid velocity (which depends on the physical properties of the liquid). ) with sufficient suction at nozzle 4
0 can be created in the area of the outlet, keeping the liquid level in the receiving container 34 below the top of said receiving container 34.

So when the pump 41 is operating, the receiving container 34
All the valves provided in the can be left open.

Now, referring to FIG. 2, as a modification of the device shown in FIG.
Separation receiving vessel 34 and supply vessel 43 can be replaced by only one vessel 60.

The carrier is fed into the tank 60 from the lid 29 of the receiving chute 28 and directed towards the outlet 61, for example by the shape of the tank 60 and a mesh plate 62 with a number of holes adjacent to one end of the tank.

As previously described, the nozzle 40 is below the outlet 61 and the carrier is drawn into the upward duct 38 under gravity and the suction effect created by the nozzle 40 as previously described. Moving.

The return pipe 48 carries excess liquid from the separation container 39 to the supply tank 60.
Return to.

The volume of tank 60 can be made sufficient to hold all of the liquid in the system, so then there is no need to provide any valves, as in the case of receiving vessel 34.

To remove entrained air or gas from the liquid system, one or more baffles 63 or screens 64 are provided in the supply tank 60 or in the return pipe 48 and a follow-up tank (not shown). The liquid can then flow from the tank to the tank 60.

Screen plate 62 prevents carrier 20 from being sucked into pump 41 through liquid outlet 64 .

In the alternative variant illustrated in FIG. 3, the liquid supply tank 10 is connected directly to the input lower 2 of the pump 13 via the outlet T1.

Pump γ3 is one of the few centrifugal pumps available on the market that can handle liquids containing solids, for example 10 mm in diameter or larger, without damaging the solids.

Since the device does not lend itself to the installation of a valve 44 (FIG. 1) to control the flow rate of liquid, this control is accomplished by varying the speed of the pump vanes.

For example, if the vane is mounted on the shaft 15 and the bearing 1
6 and driven by a pulley 11, a drive belt 70, and an electric motor 19, then the speed of the pump vanes can be varied by changing the ratio of the pulley 17.

Alternatively, pump 73 can be driven through a variable speed gear box (not shown) or coupled directly to a variable speed electric motor.

The outlet of the pump 13 is connected to an upstream duct 38 which conveys the liquid and carrier to a separation vessel, as previously mentioned.

The features described for tank 60 can also be applied to tank 10.

[Brief explanation of drawings]

The drawings are schematic diagrams for explaining the invention in detail, and the first
The figure is a cross-sectional elevational view showing a first embodiment of the device of the invention, and FIG. 2 is a portion illustrating modifications of the device of FIG. 1 forming a second embodiment of the device of the invention. FIG. 3 is a partial elevational view to be compared to FIG. 2 providing a third embodiment of the apparatus of the invention. 10... Tower or container, 11... Processing chamber, 12... Current transformer, 13... Discharge disk, 20... Carrier, 21... Gas inlet space, 22... Gas inlet hole, 23...
・Waste gas outlet, 24...Carrier inlet, 28...
...Receiving chute, 34...Receiving container, 38...Upward duct, 39...Separation container, 40...Curved nozzle, 41... pump,
43... Supply tank, 45... Partition plate,
46... Carrier return duct.

Claims (1)

[Claims] A liquid, which is a suspension or solution of 11 solids, is applied to the surface of a number of carriers to wet the carriers, and some or all of the moisture is evaporated from the liquid, leaving a dry or substantially The liquid is treated continuously by blowing a gas through the bed of carrier in the process chamber, leaving a thin film or layer of dry solids as it moves downward through the bed and The solids in the liquid are recovered by separating the solids from a carrier that appears at the bottom and is carried to the top of the bed, which emerges from the bed and is then flowed through it after separating the solids. A continuous liquid application system comprising an upward duct carried by the liquid, and further characterized in that the liquid, after emerging at the upper end of said duct, is separated from the liquid and proceeds to the upper part of the processing chamber. How to process. 2. After the said carrier has separated the solids, it passes alternately into one or the other of the two receiving vessels, from which one is isolated and receives the carrier when one of said receiving vessels supplies the carrier to the liquid application system. 2. A method as claimed in claim 1 for receiving or vice versa. 3. A method as claimed in claim 1, in which a pump causing upward flow in the upward duct lifts the liquid through a nozzle which serves to carry the carrier along with the liquid. 4. Said carrier, after separating the solids, passes to a receiving vessel and from there into an upward duct, said nozzle maintaining the level of the liquid in said vessel and carrying air along with the liquid. 4. The method of claim 3, wherein suction is generated sufficient to avoid. 5. A method as claimed in claim 1, in which the pump causing upward flow in the upwardly directed duct is arranged such that the carrier passes therethrough. 6. Claims 1, 2, 3, 4, or 5, in which the liquid appearing at the upper end of the upward duct and the carrier are separated by flowing over a perforated partition plate.
The method described in section. 1. Apparatus for applying a liquid to the surface of a carrier by wetting a number of carriers with a liquid that is a suspension or solution of one solid, containing said carrier and also applying a dry or substantially dry liquid onto the carrier. a treatment chamber having a device for blowing gas through a bed of carrier so as to cause evaporation of some or all of the moisture from the liquid to leave a thin film or layer of solid, from the carrier moving downward through the bed a device for recovering dry or substantially dry solids by separating the solids; and a conveying device for conveying the carrier emerging from the bottom of the bed back to the top of the bed, the conveying device comprising: , a liquid application system through which the carrier emerges from the bed and separates the solids, said liquid application system comprising an upward duct and a device for causing the liquid to flow upwardly therethrough while simultaneously carrying the carrier; and a device for continuously processing a liquid, characterized in that it comprises a separating device provided at the upper end of the duct for separating the carrier from the liquid and sending it back to the upper part of the processing chamber. 8 Claim 7 in which the carrier is a sphere or a polyhedron
Apparatus described in section. 9 Two receiving vessels are provided for the carrier to pass through it alternately after separating the solids, said receiving vessels being such that one vessel supplies the carrier to the liquid system, while the other vessel supplies the carrier from said system. 9. A device according to claim 7 or 8, which receives the carrier in isolation and vice versa. 10. Apparatus according to claim 1 or 9, comprising a pump serving to flow the liquid upwardly into the upward duct and lifting the liquid through a nozzle arranged to carry the carrier with the liquid. . 11 comprising a separation vessel arranged to receive the liquid emerging from the upper end of the upward duct and from which the carrier is separated; the nozzle is arranged to receive the liquid emerging from the upper end of the upward duct, and the nozzle is arranged to separate the liquid from said separation vessel while avoiding air being carried along with the liquid; 11. The device of claim 10, constructed to generate suction sufficient to maintain a level of liquid therein. 12. Apparatus according to claim 1 or claim 8, comprising a pump configured to cause the liquid to flow upwardly into the upwardly directed duct and arranged so that the carrier passes therethrough. 13. Claims 1, 8, 9, 1, comprising a separation vessel located at the upper end of the upward duct and consisting of an inclined perforated partition plate for separating the carrier from the liquid.
The device according to item 0, item 11, or item 12.