JPH0443693B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a slurry storage tank for storing slurry such as coal-water mixture (CWM) or coal-oil mixture (COM).

[Prior Art] When attempting to use coal as an alternative fuel to petroleum, there is a problem in that coal is solid and therefore difficult to transport, store, and handle.
Therefore, a technique has been developed in which the coal is broken into frames and mixed with water or oil and additives added as necessary to form a fluid (slurry). By the way, when such a slurry is stored for a long period of time, as a result of particles settling, the lower layer becomes thicker and further solidifies, resulting in problems such as difficulty in smooth discharge. Therefore, the coal particles are dispersed by blowing air into the storage tank or mechanically stirring to maintain a uniform concentration of the slurry. Alternatively, a method has been proposed in which the thickened slurry in the lower layer is scraped out using a scraper or a conveyor and then circulated to the upper part of the tank using a pump.

[Problems to be Solved by the Invention] However, in order to obtain a sufficient effect of preventing deposition and solidification by the method described above, a large amount of energy is required to move the slurry with a high specific gravity, and the operation is slow. The cost will increase.

Generally, the internal structure of a non-Newtonian fluid such as a slurry changes as it flows, so its viscosity properties change depending on the deformation rate. In other words, it exhibits a very high viscosity in the low shear rate region, forming a stable slurry with no particle sedimentation, and the internal structure consisting of bonds between particles is destroyed in the process of transitioning from a static state to a fluid state. This results in a low viscosity slurry that is easier to transport. Therefore, overflowing the slurry will cause it to lose these properties and
On the contrary, it will promote sedimentation and sedimentation. Therefore, it can be said that an appropriate method is to allow the slurry to stand still in the tank without stirring or circulating the slurry as described above, and to maximize its standing stability and store it.

This invention was made with attention to these points, and it is possible to store slurry smoothly and economically using a device with a relatively simple configuration while suppressing the flow of slurry to the necessary minimum. The purpose of this invention is to provide a slurry storage tank that can

[Means for Solving the Problems] The present invention includes a bottomed cylindrical storage tank having a discharge port in the center of the bottom plate, a scraper that is rotatable along the bottom plate, and a scraper that can be rotated in forward and reverse directions. The scraper is provided with a scraping surface that is inclined or curved to move the slurry upward when the scraper rotates in the normal direction, and a scraping surface that moves the slurry to the center of the bottom plate when the scraper rotates in the reverse direction. It has a sloped or curved scraping surface.

[Function] When storing slurry, the scraper is rotated in the normal direction at a very slow speed, and the scraping surface creates a flow that moves the slurry near the bottom plate upward, mixing the slurry near the bottom plate of the storage tank with the slurry in the upper layer. Prevent accumulation and solidification and store statically. In addition, when discharging slurry, the scraper is reversed at a higher speed, and the scraping surface creates a flow near the bottom plate that moves the slurry to the center of the bottom plate, allowing the slurry to be discharged from the discharge port. do.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings.

In these drawings, 1 is a cylindrical storage tank with a bottom, the bottom plate 2 of which is sloped in the shape of a funnel so that the center is lower, and the bottom plate 2 is located inside the inner wall 1a.
The upper part is a stationary chamber 1b, and this bottom plate 2
A cylindrical stirring chamber 3 with a bottom is located lower in the center of the
is provided. This stirring chamber 3 also has a funnel-shaped inclined bottom plate 3a, a discharge port 4 is formed in the center thereof, and an annular convex wall 3b projecting slightly upward is provided at the upper edge. The stationary chamber 1b and the stirring chamber 3 are partitioned to prevent the influence of stirring in the stirring chamber 3 from affecting the stationary chamber 1b.

A support bridge 5 is constructed on the upper surface of the storage tank 1, spanning the storage tank 1, and a hole 5a is provided in the center of the support bridge 5.
A rotary shaft 6 is inserted perpendicularly into this hole 5a. This rotary shaft 6 has a support part 6a formed in the shape of a flange at its upper end, and is supported by an elevating support mechanism 7 installed on the upper surface of the support bridge 5 so as to be able to rise and fall. By being rotated by the stirring mechanism 8,
The slurry in the stirring chamber 3 is stirred by rotating stirring blades 39, which will be described later. The lifting support mechanism 7 includes a plurality of hydraulic jacks 7a installed around the hole 5a on the support bridge 5, a ring body 7b connecting the movable ends of the hydraulic jacks 7a, and a ring body 7b. It is comprised of a bearing 7c that is installed between the support part 6a and rotatably supports the rotary shaft 6, and a hydraulic motor 7b that drives the hydraulic jack 7a. Also,
The stirring mechanism 8 includes a stirring drive motor 8a installed on the support bridge 5, and a gear box 8b that transmits the rotational force of the stirring drive motor 8a to the rotating shaft 6. It is connected to the rotating shaft 6 so as to be movable in the axial direction.

A stirring structure 9 for stirring the stationary chamber 1b is rotatably attached to the rotating shaft 6. That is, a cylindrical member 10 is rotatably mounted on the upper part of the rotating shaft 6, a plurality of beam members 11 are attached radially to the outer surface of the cylindrical member 10, and a ring member is attached to the outer end of each beam member 11. 12, and this ring member 12 has a rail 1 laid annularly on the floor 1c around the storage tank 1.
A plurality of wheels 14 are provided to run on the vehicle.
A mounting member 15 having a vertical through hole 15a is attached to a position slightly inside the storage tank inner wall 1a of each of the beam members 11, and a vertical arm 16 is inserted into the through hole 15a. At the same time, the fixing bracket 1 provided at the upper end of the vertical arm 16
7 is supported in contact with the mounting member 15.
Further, stoppers 18 and 19 are fixed to a position slightly below the vertical center of the rotating shaft 6 and near the lower end.
Cylindrical members 20 and 21 are rotatably and slidably mounted above the stoppers 18 and 19 of the rotating shaft 6, respectively. And these cylindrical members 2
0,21 and the vertical arm 16,
A first arm 22 on the lower side and a second arm 23 on the upper side are installed radially and parallel to the bottom plate 2, and each first arm 22 has a scraper 24 with a minute gap from the bottom plate 2. ..., and a plurality of ailerons 25... are attached to each second arm 23, respectively. As shown in FIG. 3 (the left side of the figure is the center side of the storage tank 1, and the same is true for FIG. 4), the scraper 24 has a scraping surface formed in the forward rotation direction as an arcuate surface or an inclined plane with the lower side protruding. 26, and a wavy claw portion 27 is formed at the lower end thereof, while the front surface in the reverse direction is a scraping surface 28 formed as an inclined plane with the outer side protruding. Therefore, when the scraper 24 rotates in the normal direction, the slurry flows upward, and when the scraper 24 rotates in the reverse direction, the slurry flows toward the center. Further, as shown in FIG. 4, the aileron 25 has a flat plate-like member attached to the second arm 23 with its lower and inner sides protruding in the normal rotation direction. The slurry is made to flow upwardly and outwardly during rotation, and downwardly and inwardly when reversed.

These cylindrical members 10, 20, 21, beam member 11, first arm 22, scraper 24, second arm 23, ailerons 25, and vertical arm 16 together constitute the stirring structure 9. and
The ring member 12 is rotatably driven by a scraper drive mechanism 29 installed between the floor 1c and the ring member 12. This scraper drive mechanism 29 includes a scraper drive motor 30 installed on the floor 1c,
A variable reversible device 31 provided on the output shaft of this scraper drive motor 30, a pinion 32 attached to the output shaft of this variable reversible device 31, and the ring member 1
2, and the above pinion 3 is attached to the top surface.
A ring-shaped rack 33 having teeth that mesh with 2
The stirring structure 9 can be rotated reversibly in either forward or reverse direction, and at different speeds.

The fixing fitting 17 at the upper end of the vertical arm 16 is positioned so that the scraper 24 has an appropriate distance from the bottom plate 2, and at this time, the cylindrical member of the stop flange 18, 19 of the rotating shaft 6 20, 21
and are set to have appropriate intervals,
Therefore, in the state shown in FIG. 1 in which the lifting support mechanism 7 is not operating, the vertical arm 16 and the first arm 2
2. The loads of the scraper 24, second arm 23, and auxiliary wing 25 are supported by the beam member 11 via the fixture 17 and the mounting member 15.

A scraping plate 34 is attached to the vertical arm 16 at a position facing the upper part of the inner wall 1a of the storage tank 1, which moves along the inner wall 1a as the vertical arm 16 rotates and prevents slurry from sticking to the inner wall 1a. has been done. In addition, an inner wall 1 of the storage tank 1 is provided at the upper edge of the storage tank 1.
An annular liquid supply groove 35 having an inner edge wall 35a formed by extending the upper edge of a is formed, and slurry liquid supply pipes 36 are communicated with this liquid supply groove 35 at a plurality of locations. The supplied slurry evenly overflows the inner edge wall 35a from the liquid supply groove 35 and is supplied into the storage tank 1, and a scraper plate is provided to prevent the slurry from sticking to the liquid supply groove 35. 37 is provided vertically from the beam member 11.

As shown in FIG. 5, a stirring blade 39 having a cylindrical drum 38 on the outside and blades 40 on the inside is attached to the portion of the rotating shaft 6 inside the stirring chamber 3. As shown in FIG. Further, a screw member 42 is screwed into the side wall 41 of the stirring chamber 3, and an arc plate-shaped steadying member 43 is pivotally attached to the tip of each screw member 42. By rotating, the anti-vibration member 43 is brought into contact with the drum 38, and the rotating shaft 6 is fixed. Note that this steadying member 43 may be inserted into the stirring chamber 3 using a spring or the like, and this spring may be automatically activated by a signal from a seismometer or the like. Below the stirring blades 39 of the rotating shaft 6, vertical blades 44 shaped like a cross are attached along the slope of the bottom plate 3a. Further, these stirring blades 39 and vertical blades 44 rotate integrally with respect to the rotating shaft 6, and are slidably attached in the axial direction of the rotating shaft 6.
Even if it moves up and down, its position in the height direction does not change.

The upper space R of the storage tank 1 is airtightly covered by a peripheral wall 45 and a dome-shaped roof 46 that are erected on the floor 1c so as to surround the storage tank 1. This roof 46 is integrally manufactured from a lightweight and high-strength material such as reinforced plastic, and can be lifted and removed using a crane or the like to remove adhering slurry in the storage tank 1 and maintain and inspect each machine. It has become easier to perform tasks such as Additionally, a sensor 47 that measures the humidity and temperature of this space R, and an air conditioning system 48 that adjusts the humidity and temperature of the space R as necessary to prevent the moisture in the slurry from evaporating and increasing the slurry and concentration are installed. has been done. This air conditioning equipment 48 is one that blows outside air into the aquarium, increases humidity through gas-liquid contact, and sends it into the space R, or one that sprays water droplets into the space R. Additionally, a device equipped with a temperature adjustment mechanism may be used if necessary. Note that the roof 46 may be configured as a bellows-shaped member that extends and contracts on a pair of rails so that it can be opened and closed to facilitate maintenance and inspection.

Next, the operation of the slurry storage tank configured as described above will be described in the case of storing CWM.

CWM is generally produced by finely pulverizing coal and mixing it with water and additives to reduce unburnable components (ash). The liquid is sent through the liquid supply pipe 36 by a pump (not shown) to the liquid supply groove 3.
The CWM supplied to the plurality of locations in the liquid supply groove 35 evenly overflows from the inner edge wall 35a of the liquid supply groove 35 to the entire inner wall 1a, flows into the storage tank 1, and is stored. The slurry that has flowed into the storage tank 1 changes over time and reaches a stable state of high viscosity, but tends to thicken slightly over time in the lower part. In other words, near the bottom plate 2 of the storage tank 1, slurry particles do not settle or accumulate at all, but they gradually accumulate and solidify, albeit at a very slow rate. There is a possibility that it will come. Therefore, the scraper drive mechanism 29 is activated in order to prevent the slurry from stagnation and particle accumulation in a very limited range in contact with the bottom plate 2 of the standing chamber 1b of the storage tank 1. That is, when the scraper drive motor 30 is operated at low speed with the variable reversible device 31 set to the normal rotation side, the rotation is transmitted to the ring member 12 via the variable reversible device 31, the pinion 32, and the rack 33. The inside of the stirring structure 9 is integrally rotated forward. This rotation causes the scraping surface 26 of the scraper 24 to slide the slurry near the bottom plate 2 of the storage tank 1 upward and mix it with the slurry near the top. At this time, the aileron 2
0 further scrapes up the slurry scraped up by the scraper 24 to the center of the storage tank 1 to help prevent particles from settling and accumulating. At this time, by setting the rotation speed of the stirring structure 9 to a low speed, such as one rotation every 10 to 30 days, the stirring speed can be set to maintain the internal structure of the slurry, which is a non-Newtonian fluid, and increase the viscosity. A low shear rate range that maintains
It suppresses excessive flow and maintains the stability of the slurry, and also reduces the energy required and reduces operating costs. Note that the second arm 23 of the aileron 25
The attachment angle to the aileron 25 may be made variable using a screw or the like, so that the action of the aileron 25 can be adjusted.

On the other hand, in the stirring chamber 3, it is desirable to ensure the fluidity of the slurry, especially when transporting, and the stirring mechanism 8 is operated as appropriate to stir the slurry in the stirring chamber 3 to make it uniform. That is,
When the stirring drive motor 8a is operated, its rotation is transmitted to the rotating shaft 6 via the gear box 8b, and the stirring blade 39 and vertical blade 44 attached to the lower part
is rotated at a much faster speed than the stirring structure 9. This rotation uniformly stirs the slurry in the stirring chamber 3, and the turbulent flow caused by this stirring is suppressed from being transmitted upward by the convex wall 3b provided at the upper end of the stirring chamber 3. The effects of disturbing the environment are kept to a minimum.

When discharging the slurry, a discharge pump (not shown) is operated, the variable reversible device 31 is switched to the reverse side, and the scraper drive motor 30 is
operates at a much higher speed than normal rotation,
Further, the stirring drive motor 8a is activated. The rotation of the scraper drive motor 30 causes the stirring structure 9 to rotate in reverse, and due to this rotation, the scraping surface 28 of the scraper 24 causes the slurry near the bottom plate 2 of the storage tank 1 to flow near the center, and the slurry above the convex wall 3b flows. The mixture is then sent to stirring chamber 3. Additionally, the ailerons 20 also send the slurry downward and inward to assist the slurry moving action of the scraper 24. In the stirring chamber 3, the slurry sent from above is further stirred by the blades 40 and the vertical blades 44, and is discharged from the discharge port 4. The rotational speeds of the stirring structure 9 and the rotating shaft 6 at this time are adjusted according to the amount and concentration of the slurry to be discharged. The internal structure of the slurry in the stirring chamber 3 is destroyed by stirring by the blades 40 and the vertical blades 44, and the slurry becomes low in viscosity.
This prevents the discharge port 4 from being blocked and facilitates discharge.

For example, if the amount of particles settling on the bottom plate 2 of the storage tank 1 increases and the viscosity increases due to only storage without transportation, the load on the scraper drive motor 30 becomes excessive. Lifting support mechanism 7
is activated to raise the stirring structure 9. That is, by operating the hydraulic motor 7b, the hydraulic jack 7a is activated.
When the rotating shaft 6a is pushed up via the ring body 7b and the bearing 7c, the rotating shaft 6 rises, and the stoppers 18, 19 fixed to the rotating shaft 6 push up the projecting members 20, 21, and the first Arm 22
Then, the scraper 24, the ailerons 25, and the vertical arm 16 are raised via the second arm 23. Here, when the scraper drive mechanism 29 is operated, the scraper 24 rotates in the slurry with a low concentration, so the load is reduced and stirring can be performed smoothly. Then, the slurry near the bottom plate 2 is scraped up and thinned by the stirring of the scraper 24, and the lifting support mechanism 7 is operated to gradually lower the scraper 24.

In the storage and discharge process described above, moisture from the slurry is removed by operating the air conditioning equipment 48 and controlling the humidity in the space R so that the vapor pressure is equal to or slightly higher than the saturated vapor pressure at that temperature. evaporation and changes in the properties of the slurry. Further, if necessary, the above objective may be achieved by operating the temperature adjustment mechanism of the air conditioner 48 to lower the temperature in the space R and lower the saturated vapor pressure.

When removing deposits or carrying out repair work, the roof 46 is suspended and removed using a crane or the like, and if necessary, the peripheral wall 45 is removed so that a crane truck or the like can be brought closer to the storage tank 1 and removed. You can work freely within 1. In this case, the roof 46 is
Since the structure is supported only by 5, there are no obstructive supports inside the storage tank 1, making it easy to work. As a method of supporting the roof 46, the air pressure in the space R may be made slightly higher than the outside pressure to push up the roof 46 and reduce the load on the peripheral wall 45.

In such a slurry storage tank, a scraper 24 installed near the bottom of the storage tank 1 is used to scrape up only a small amount of the slurry at the bottom of the tank to prevent the thickened slurry from accumulating and solidifying. without impairing the static stability of the slurry. Furthermore, each scraper 24 is formed with a scraping surface 26 and a scraping surface 28, which perform two functions by forward and reverse rotation of the rotating shaft 6, compared to the case where these two surfaces are provided separately. The device can be simplified and costs can be reduced. In addition, a standing chamber 1b and a stirring chamber 3 are provided, and each part performs separate functions of standing and storing the slurry, and stirring and discharging the slurry, thereby eliminating the influence of one from the other. It has little effect on In addition, separate drive mechanisms are provided to stir each, so
The rotation speed can be set and changed independently, making the above-mentioned division of functions more effective and allowing storage and discharge to be performed in accordance with the properties of the slurry. roof 46
The space R above the storage tank 1 is airtightly covered by the surrounding wall 45, and the humidity and temperature of this space R are adjusted by the air conditioner 48, thereby preventing moisture from evaporating from the slurry and improving the properties of the slurry. never changes. In addition, in the event of an earthquake, the vibration damping member 43 provided on the side wall 41 of the stirring chamber 3 engages with the drum 38 of the stirring blade 39, so that the rotating shaft 6, the first arm 22, and the second arm
Damage caused by excessive vibration such as 3 can be prevented.

The above example is for a device that stores coal slurry that does not generate any volatilization, but in the case of slurry such as COM where the oil content is likely to volatilize and catch fire,
Scraper drive motor 30, stirring drive motor 8a
Measures may be taken such as making the roof 46 explosion-proof or installing it outside the roof 46 (in that case, make it a fixed roof).

[Effects of the Invention] As detailed above, the present invention includes a bottomed cylindrical storage tank having a discharge port in the center of the bottom plate, a scraper that is rotatable along the bottom plate, and a scraper that can be rotated in forward and reverse directions. The scraper is provided with an inclined or curved scraping surface that moves the slurry upward when the scraper rotates in the normal direction, and a drive device that moves the slurry toward the center of the bottom plate when the rotation shaft rotates in the reverse direction. Since the slurry is formed with an inclined or curved scraping surface, it suppresses the flow of the slurry to the necessary minimum, suppresses the accumulation and solidification of particles, and allows smooth storage and discharge of the slurry. This has the excellent effect of simplifying the device.

[Brief explanation of drawings]

FIG. 1 is a sectional view of an embodiment of the invention, FIG. 2 is a plan view thereof, and FIG. 3 is an enlarged perspective view of the main parts.
Figure 4 is an enlarged perspective view of the main parts, and Figure 5 is the second
The V-V arrow view in the figure and FIG. 6 are enlarged views of the main parts. 1... Storage tank, 2... Bottom plate, 4... Outlet, 7...
...Lifting support mechanism, 24...Scraper, 26...
Scraping surface, 28... Scraping surface, 29... Scraper drive mechanism, 31... Variable reversible device, 10... Lifting motor, 17... Arm, 18... Scraper, 1
8a... Raised surface, 18b... Raised surface.

Claims (1)

[Claims] 1. A storage tank in the form of a bottomed cylinder having a discharge port in the center of the bottom plate, a scraper rotatably provided along the bottom plate, and a drive device for rotating the scraper in forward and reverse directions. The scraper has an inclined or curved scraping surface that moves the slurry upward when the scraper rotates in the normal direction, and an inclined or curved scraping surface that moves the slurry toward the center of the bottom plate when the scraper rotates in the reverse direction. A slurry storage tank characterized in that a scraping surface is formed. 2. The slurry storage tank according to claim 1, further comprising means for moving the scraper up and down.