JPS63294932A - Slurry storage vessel - Google Patents

Abstract

PURPOSE:To prevent the particles of slurry from settling and accumulating by constituting the scraper provided with a driving unit rotating said scraper with variable speed so as to move the slurry upward as well as in the central direction. CONSTITUTION:The particles of a slurry (for instance, the mixture of coal and water, etc.) stored in a storage vessel 1 are gradually settled and accumulated on the bottom plate 2 with the lapse of time. In this case, it is enough for preventing the accumulation only to prevent the accumulation on the area brought into contact with the bottom plate 2; a motor 31 for driving the scraper is put into operation to rotate an annular member 26, and the scraper 34 moves the slurry to slide on a slanting surface and then to hoist upward slightly to the central direction to be mixed with the slurry near the upper part with the result that the particles of slurry near the bottom part are prevented from accumulating. The revolving velocity is kept in a low shearing velocity range, such as one revolution per 10-30 days, so that the slurry is agitated keeping high viscosity to prevent the particles of slurry from accumulating and solidifying. Further in the case of discharging the slurry, the motor 31 for driving the scraper is revolved in a higher speed.

Description

[Detailed Description of the Invention] [Industrial Field of Application] This invention applies to coal-water mixtures (CWM) or coal-water mixtures (CWM) or coal-water mixtures (CWM).
Economically stores slurries such as oil mixtures (COM),
It also concerns a slurry storage tank 7 that can be smoothly discharged.

[Prior Art] When attempting to use coal as an alternative fuel to petroleum, there is a problem in that it is difficult to transport, store, and handle because coal is solid.

Therefore, a technology has been developed in which coal is crushed and mixed with water or oil and additives added as necessary to form a fluid (slurry). By the way, if such slurry is stored in a storage tank for a long period of time, the particles will settle and the lower layer will become thicker, making it impossible to supply slurry with an appropriate concentration, and the particles will accumulate near the outlet. This may cause problems such as accumulation, making it impossible to discharge smoothly, and further solidifying and blocking the discharge port. Therefore, it is necessary to install a device to blow air into the storage tank, or to install a mechanical stirring device to stir the inside of the tank to disperse the coal particles and maintain a uniform concentration of the slurry. Methods have been proposed in which the thickened slurry is scraped out using a scraper or 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 sufficient effects in the above method, a large amount of energy is required to move the slurry having a high specific gravity, resulting in high operating costs.

Considering the characteristics of a non-Newtonian fluid such as coal slurry, it has a very high viscosity in the low shear rate region, so that there is little particle sedimentation in a static state, and the fluid transitions from a static state to a fluid state. During the process, a certain amount of energy is absorbed and the bonding state between the particles changes, resulting in a slurry with a low viscosity that becomes easier to transport. Therefore, if the slurry is allowed to flow excessively, its viscosity decreases and its stability decreases. This will actually promote sedimentation and sedimentation. Therefore, it can be said that the most appropriate method is to leave the slurry stationary in a storage tank to maximize its stability and store it without stirring or circulating the slurry as described above.

This invention was made with attention to these points.
It is an object of the present invention to provide a storage tank that can store slurry smoothly and economically while suppressing the flow of slurry to the necessary minimum.

[Means for Solving the Problems] The present invention includes a cylindrical storage tank having a discharge port in the center of the bottom plate, a scraper that is rotatable along the bottom plate inside the storage tank, and a scraper that can be rotated at a variable speed. A rotating drive device is provided, and the scraper is configured to move the slurry upward and toward the center as the scraper rotates.

[Function] In the slurry storage tank of the present invention, when storing the slurry, by rotating the scraper at a slow speed for an appropriate time, the slurry can be stored while maintaining stability without changing the bonding state of the non-Newtonian fluid. It is possible to prevent the concentration and sedimentation of particles, allow the slurry to stand still in the storage tank, and to maximize its stability for storage.

[Example code] Embodiments of the present invention will be described below with reference to the drawings.

1 to 3 show an embodiment of the present invention,
In these drawings, 1 is a cylindrical storage tank with a bottom,
The bottom plate 2 is formed to be inclined in a funnel shape so that the center is lower, and a stirring chamber 3 is provided in the center of the bottom plate 2, and the other part is a stable chamber 1a. This stirring chamber 3 includes a funnel-shaped inclined bottom plate 4 having a larger slope than the bottom plate 2, and
A plurality of plate-shaped supports 5 are erected from the upper end of the inclined bottom plate 4 toward the center so as to cover the upper space of the inclined bottom plate 4 in the shape of a truncated cone, and a ceiling supported on the upper end of the supports 5. It is composed of a plate 6. A discharge lower is formed in the lower part of the inclined bottom plate 4, and a vertically elongated slit 5a with a widened lower part is formed between the adjacent supports 5, so that the slurry can flow therethrough. A hollow cylindrical support tower 8 is erected on top of the top plate 6. A disk-shaped support plate 11 having a bearing portion 1° at the center is fixed to the upper surface of the flange portion 9 at the upper end of the support tower 8.
The stirring shaft 12 is vertically and rotatably supported by a shaft seal 6a formed at the center of the top plate 6. The lower end of the stirring shaft 12 reaches the vicinity of the inclined bottom plate 4 of the stirring chamber 3, and a plurality of arms 13 extending radially from the stirring shaft 12 are provided in the portion of the stirring shaft 12 inside the stirring chamber 3. A first stirring blade 14a and a scraping blade 14b are provided therebetween, and a second stirring blade 15 is provided at the lower end of the stirring shaft 12.

The first stirring blade 14a is located approximately at the center of the height of the stirring chamber 3,
Further, the second stirring blade 15 is located at approximately the same height as the discharge lower, and these stirring blades 14a and 15 have a vertical plate shape. On the other hand, the scraping blade 14b is installed parallel to the inclined bottom plate 4 with an appropriate gap therebetween, and its shape is similar to that of the scraper 34 described later.
Similarly, it has a shape with an inclined surface or an arcuate surface with respect to the vertical surface. This stirring shaft 12 is driven by a gear 17 by a stirring drive motor 16 installed on the support plate 11.
．． It is designed to be rotationally driven via 18.

On the other hand, an annular inner rail 19 is laid on the lower surface of the flange portion 9 along the outer surface of the support tower 8, and a support ring 20 is rotatably mounted on this inner rail 19 as shown in FIG. is suspended from the This support ring 20 has a ring member 21 having a U-shape with an upwardly open cross section, and a pair of wheels 22 mounted on inner surfaces facing each other at appropriate positions in the circumferential direction.
is attached with its shaft 23 cantilevered.

The vertical portion 19a of the inner rail 19 is inserted between the wheels 22, and the horizontal portion 19b of the inner rail 19 is inserted between the wheels 22.
The wheels 22 run on the upper surface of the vehicle. An inner annular member 24 is fixed to the lower surface of the support ring 20, beam members 25 are fixed radially to the outer periphery of the inner annular member 24, and the outer end of each beam member 25 is fixed to an outer annular member 26. ing. On the lower surface of this outer annular member 26, an annular outer rail 27 is provided on the upper surface of the peripheral edge of the storage tank 1.
Wheels 28 are provided which run on the outer annular member 2.
A variable speed scraper drive motor 31 is installed on the wheel 6 to rotate the wheel 28 via a pulley 29 and a belt 30. Note that this scraper drive motor 31 may be installed on the floor lc around the storage tank l. Below the beam member 25 and the inner annular member 24, a plurality of vertical arms 32 are vertically installed at appropriate positions in the radial direction, and the lower part of the vertical arms 32 has a plurality of stages (not shown in the figure) extending in the radial direction of the storage tank 1. They are connected and reinforced by horizontal arms 33 (3 stages). The lowermost horizontal arm 33 is connected to the inclined bottom plate 2 of the storage tank 1.
A plurality of scrapers 34 close to the bottom plate 2 are attached to each horizontal arm 33 in parallel to each other.

As shown in FIG. 3, the front surface of each scraper 34 in the rotation direction is a sloped surface or a curved surface formed such that the lower side protrudes in the rotation direction, and the outer side of each scraper 34 in the radial direction protrudes in the rotation direction. It is attached diagonally to the horizontal arm 33. A claw portion 35 is formed at the lower end of the scraper drive motor 31 to rotate the beam member 25, and when the horizontal arm 33 rotates in the direction of arrow A, the slurry near the bottom plate 2 of the storage tank 1 is removed. is moved to the center and upward of the storage tank l. Incidentally, the inclined surface of the scraper 34 may be an arcuate surface like a part of a sphere which is inclined so that the outer side and the front surface in the direction of rotation protrude.

A support 5 is attached to the lower end of the vertical arm 32 at the top of the stirring chamber 3.
An inner scraper 34a is attached to the inner scraper 34a, and this inner scraper 34a has a flat plate member attached at an angle with respect to the horizontal arm 33, and when the beam member 25 rotates in the direction of the arrow six, the slurry in the stability chamber 1a is removed. is sent to the stirring chamber 3.

At a position of the outermost vertical arm 32 facing the upper part of the inner wall 1b of the storage tank l, there is a plate-shaped scraper that moves along the inner wall tb as the vertical arm 32 rotates and prevents the slurry from sticking to the inner wall tb. A mounting plate 41 is attached. An annular liquid supply groove 43 having an inner edge wall 42 with an extended inner wall 1b is formed at the upper edge of the storage tank l, and slurry is supplied to this liquid supply groove 43 at positions that equally divide the circumference of the storage tank l. A plurality of liquid pipes 44 are connected,
The slurry supplied through the liquid supply pipe 44 overflows the inner edge wall 42 from the liquid supply groove 43 and is evenly supplied into the storage tank l.

Further, a scraping plate 45 that prevents slurry from sticking to the liquid supply groove 43 is provided vertically from the beam member 25.

The space R above the storage tank 1 is covered by a peripheral wall 46 erected on the floor IC around the storage tank 1, and a roof (covering member) 47 placed on the peripheral wall 46 and fixed with bolts or the like. The roof 47 has a dome shape and is made of a material such as reinforced plastic to be lightweight and strong so that the load can be supported only by the peripheral wall 46, and can be removed using a crane or the like. . In addition,
The roof 47 does not have to be all integral; for example, it may be divided into two along a vertical plane including the center. Further, the peripheral wall 46 is partially or completely removable.

Air conditioning equipment 48 is installed outside the peripheral wall 46, and sensors 49 for measuring the temperature or humidity of the space R are installed at appropriate locations inside the peripheral wall 46 or the roof 47. This air conditioning equipment 48 blows outside air into a water tank (not shown) to increase the humidity through gas-liquid contact and sends it into the space R, or it sprays water droplets into the air, and the detected value of the sensor 49 is It is operated in accordance with the above, and the humidity in the space R is adjusted to prevent moisture in the slurry from evaporating. Note that a temperature adjustment device may be incorporated into this air conditioning equipment 48 so that the temperature within the space R can be adjusted as necessary. In addition, this roof 47 may be constructed as a bellows-like member that extends and contracts on a pair of rails and can be opened and closed to facilitate maintenance of the equipment in the storage tank 1, cleaning of the inside of the storage tank 1, etc. .

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

CWM is generally produced by finely pulverizing coal and mixing it with water and additives to reduce non-flammable components (ash). The CWM is sent through the liquid supply pipe 44 by a pump (the illustrated path) and is supplied to multiple locations in the liquid supply groove 43, and uniformly overflows from the inner edge wall 42 of the liquid supply groove 43 to the entire inner wall ib and into the storage Wll. It flows in and is stored. The slurry flowing into the storage tank 1 changes over time,
Although the viscosity is stable and high, it becomes slightly thicker in the lower part of the storage tank 1 over time. That is,
Slurry particles settle and accumulate on the bottom plate 2 of the storage tank 1 at a slow rate, and if this is left for a long period of time, storage may be impaired.

In this case, it is sufficient to prevent the slurry from stagnation and accumulation in a very limited range in contact with the bottom plate 2, and the scraper drive motor 31 is operated at a low speed to rotate the outer annular member 26. The scraper 34 slides the slurry in the vicinity of the bottom plate 2 of the storage tank 1 on the inclined surface, raises it upward and slightly toward the center, mixes it with the slurry in the vicinity of the upper part, and prevents the settling and accumulation of particles of the slurry in the vicinity of the bottom. To prevent. By setting this rotation speed to a low shear rate range that maintains the internal structure of the slurry and maintains its viscosity, for example, one rotation every 10 to 30 days, most of the slurry remains at a high viscosity, and the bottom plate By stirring only the vicinity of 2, deposition and solidification can be prevented while minimizing the required energy. Stirring chamber 3
Then, the stirring drive motor 16 is appropriately rotated at a rotation speed much faster than the rotation speed of the scraper 34, and the stirring blade 14 is rotated.
The slurry is made uniform by the blades a and 15 and the scraper blades 14b. The turbulent flow generated by this stirring is blocked by the support 5, stays within the stirring chamber 3, and does not significantly affect the stability of the stable chamber 1a.

When discharging the slurry, the slurry is sucked from the discharge lower by a pump (the path shown), the scraper drive motor 31 is rotated at a higher speed than in the above case, and the stirring drive motor 16 is also rotated. Since the scraper 34 rotates at a higher speed than when it is stored, the action of scraping the slurry toward the center is strong, and the inner scraper 34
4a is parallel to the conical side surface of the support 5 and is connected to the transverse arm 3;
3, the slurry is pushed down over the entire vertical height of the inner scraper 34a. Due to these actions and the flow accompanying the discharge from the discharge lower, the slurry moves to the center of the bottom plate 2 and is sent into the stirring chamber 3, where it is uniformly stirred by the stirrs X14a and 15 and discharged from the discharge port 4. At this time, the scraping blades 14b serve to scrape the slurry thickened on the inclined bottom plate 4 toward the center, mix it, and discharge it uniformly.

The rotational speed of the scraper 34 at this time can be adjusted according to the amount and concentration of slurry to be discharged, and the rotational speed of the stirring blades 14a, 15 and scraping blades 14b can be adjusted appropriately by changing the speed of the stirring drive motor 16. You may want to adjust the speed accordingly.

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 to be equal to or slightly higher than the saturated vapor pressure at that temperature. evaporation and changes in the properties of the slurry. Alternatively, 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.

In the storage tank of this example, stirring in the stirring chamber 3 destroys the internal structure of the slurry, making the slurry low in viscosity, allowing it to be easily discharged and preventing clogging. In addition, a stabilization chamber 1a and a stirring chamber 3 are provided, and each part performs separate functions of leaving the slurry still and storing it, and stirring and discharging it, thereby eliminating the influence of one from the other. It has little effect. In addition, separate drive mechanisms are provided for stirring each, so the rotation speed can be set and changed independently, making the above functional division more effective and allowing storage and storage to suit the properties of the slurry. Can be discharged. Then, the air conditioning equipment 48 adjusts the humidity in the space R and the temperature as necessary, prevents the evaporation of water from the slurry and maintains its quality constant, and prevents the settling of powder due to the concentration of the slurry, and also prevents the discharge lower. It is more effective in preventing blockages.

Note that the above example is a device for storing non-volatile slurry, but in the case of slurry such as COM where the oil content is likely to volatilize and catch fire, the stirring drive motor 16, scraper drive motor 31, etc. Measures may be taken such as making it explosion-proof or installing it outside the roof 47.

[Effects of the Invention] As described in detail above, the present invention includes a cylindrical storage tank having a discharge port in the center of the bottom plate, a scraper that is rotatable along the bottom plate inside the storage tank, and a variable speed control mechanism for the scraper. The scraper is configured to move the slurry upward and toward the center as the scraper rotates, thereby suppressing the flow of the coal slurry to the necessary minimum. The slurry can be stored economically by suppressing the accumulation and solidification of particles without adversely affecting the static and stable storage of the storage tank as a whole, and the scraper rotates at high speed during discharge to guide the slurry to the discharge port. This has the excellent effect of making it possible to do this smoothly.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an embodiment of the present invention, FIG. 2 is an enlarged sectional view of the main part, and FIG. 3 is a perspective view of the main part. 1...Storage tank, 2...Bottom plate, 7...
...Discharge port, 31...Scraper z<drive motor, 34...Scraper.

Claims (1)

[Claims] The scraper comprises a cylindrical storage tank having a discharge port in the center of the bottom plate, a scraper rotatably provided inside the storage tank along the bottom plate, and a drive device that rotates the scraper at a variable speed. A slurry storage tank is characterized in that it is configured to move slurry upward and toward the center as it rotates.