JPS6344486A - Slurry tank - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applicable to coal-oil slurry (hereinafter referred to as COM) and coal-water slurry (hereinafter referred to as CWM) stored in a tank, particularly to highly concentrated slurries of these. Circulate and stir;
This invention relates to a slurry tank equipped with a device for uniformizing slurry in the tank.

[Conventional technology]

In recent years, CWM and COM have come into use with the advancement of coal utilization technologies such as combustion in power generation boilers and coal liquefaction. For example, in CWM, the coal particle concentration was traditionally 45 to 50 wt%, but due to demands such as improving the thermal efficiency of power generation boilers, improving transportation efficiency, and storage efficiency, the coal particle concentration has increased to 65 to 80 wt%. Concentration CWM
has come to attract attention. However, the surface of coal particles is generally hydrophobic, and hydrophobic particles inherently tend to agglomerate and do not form a stable dispersion system. A dispersant is added to provide a repulsion effect or to provide a steric repulsion effect due to the thermodynamic interaction of the polymer adsorption layer formed on the surface of the coal particles. As the dispersant, nonionic ones are used, such as polymeric surfactants made of ethylene oxide, ethylene and propylene oxide, and ionic ones are used, such as anionic polynaphthalene sulfonic acid. A surfactant or the like is used. High concentration C with dispersant added in this way
In WM, the medium (water) covers the surface of the coal particles to form a continuous phase, and the coal particles are in a dispersed state. However, the dispersed coal particles are no longer interfered with by the surrounding coal particles, but instead tend to settle, and if the conditions are bad, they form a consolidated phase (octapod phase), causing serious trouble.

On the other hand, industrial CWM with a coal particle concentration of 45 to 50 wt%,
It is necessary to store high concentration CWM and COM with a coal particle concentration of 65-80 wt% in a tank for short or long term. The slurry discharged from the tank and transported is
The slurry must have a uniform concentration, and the slurry in the tank must also be in a flowable state. However, the coal particles in CWM and 00M settle, and
As the concentration of coal particles increases, the tendency to exhibit thixotropic behavior increases, and in the worst case, a consolidated phase (hard pack phase) may form in the lower part of the tank. Therefore, it is impossible to stir the slurry in the tank to make it uniform, but even if a stirring device using rotating blades is installed, the slurry storage tank is usually 1000 m long.
Since the tank is as large as described above, it is difficult in terms of the structure of the stirring device and the stirring effect. Therefore, stirring has to be carried out by a circulation method in which the slurry is extracted from the tank and then changed again, but there is no circulation method that is actually applicable industrially, especially in high-concentration CWM.

Therefore, the inventor of the present invention conducted an experiment on a slurry circulation method using a large tank. FIG. 11 is an explanatory diagram of the experimental apparatus. In the figure, (1) is a 1000d tank, (2
) is a CWM slurry with a fine coal particle concentration of about 70 wt% stored in tank (1), which has been used for about one month. CW M after 1 month (2)
, fine coal particles have settled, and the concentration of fine coal particles is high in the lower part of the tank (1). (4) is a rotary mud collecting device, (6) is a crushing mixer that crushes the coal fine particles of the slurry (2) collected by the mud collecting device (4) into lumps, and (8) is a The slurry circulation pipe, α, which communicates with the agglomeration mixer (6) is a circulation pump installed in the middle of the pipe (8).The outlet (8a) of the pipe (8) is connected to the tank (1). ) is located in the center of the area.

When slurry (2) is circulated using the above experimental equipment, slurry! J-(21) is ejected from the outlet (8a) of the pipe (8) in the vertical direction at a predetermined velocity and collides with the liquid surface (2a).

Then, the slurry flow that collided with the liquid surface (2a) flows into the tank (
1) Flow that forms a narrow flow path from directly below the outlet (8a) to the bottom of the tank (1) without being dispersed within the tank, and flows only through that flow path (branch) and circulates immediately from the circulation pump. It became clear that this would be repeated.

[Problem that the invention seeks to solve]

Conventionally, when circulating slurry to homogenize the slurry in a tank, there has been a problem that there is no industrially practical slurry tank.

[Means for solving problems]

The slurry tank according to the present invention comprises a coal-tower slurry (
COM) or coal-water slurry (CWM), in which a means for extracting the slurry from the bottom of the tank, a means for circulating the slurry extracted by the extracting means, and one or more pipes arranged in a plane. In addition, the pipe is provided with a plurality of nozzles, and the openings of these nozzles are at least comprised of a distributor located substantially on the same plane as the liquid level of the slurry in the tank or in the vicinity thereof.

[Effect]

In the slurry tank according to the present invention, the distributor is maintained almost on the same plane as the liquid level of the slurry in the tank, and the jet stream is jetted out from the distributor in a lateral direction, so that the jet stream immediately comes into contact with the slurry near the liquid surface. and the energy is attenuated. Furthermore, since the coal particles in the jet flow are in the same direction as the jet flow, they have only a horizontal velocity Ux, and fall naturally due to the energy attenuation of the jet flow.

〔Example〕

FIG. 1 is an explanatory diagram of an embodiment of the present invention.

In the figure, the same reference numerals as in the conventional example of FIG. 11 indicate the same components. (10m) is a pump with a set of screws for circulation, and (20) is a sura! J-(2+ circulation pipe (
8) with its center communicating with the distributor (20), and the plane of the distributor (20) is disposed on substantially the same plane as the liquid level (2a).

FIG. 2 is a plan view of the distributor (20). Distributor (20
) is formed by forming pipes (22m) and (22b) into a U shape, and communicating with a short pipe (24) to which a circulation pipe (8) is connected, and the pipes are arranged in a substantially cross shape. Then, the nozzle (26a) is installed only on one side of the pipes (22a) and (22b), and on the same left side respectively.
), (26b).

(26cJ).In addition, the nozzle (28m
).

(2Bb), (26e) to pipe (22a),
(22b) may be provided only on the right side of the side surface.

FIG. 3 is a partial cross-sectional view of the distributor (20), in which the slurry is ejected from the nozzle (26m) in a horizontal direction (arrow A).

Next, a tank (1
) will explain the operation of circulating the slurry (2).

First, in order to enable fluidity during transportation, 1.000mP
A highly concentrated CWM slurry (2) adjusted to a viscosity of about a, s or less is transported through a pipe and stored in a tank (1). Next, when it becomes necessary to equalize the concentration of fine coal particles in the tank (1), the blades of the mud collecting device (4) are rotated to i! I
The m slurry is collected in the center and crushed by a crushing mixer (6) to form a slurry with fine coal particles separated, which is circulated through a pipe (8) by a screw pump (10a). In addition, in the agglomeration mixer (6), if there is a lump of fine coal particles, most of the lump, specifically 95% or more, is crushed to form a slurry of fine coal particles. Tank (1)
Sura pulled out from the bottom of! J-(2) is because when the concentration of fine coal particles is high and large lumpy particles are mixed in, the viscosity of slurry (2) becomes significantly thick.

For example, Figure 4 is a diagram showing the relationship between coal particle concentration and slurry viscosity in CWM. Because of this, slurry of the same concentration has a significantly higher viscosity in the high concentration region.As shown in Figure 3, slurry (2)
) to (26c) in the horizontal direction as shown by arrow A. In this case, if the horizontal velocity of the fine coal particles in the jet stream is Ux, and the vertical velocity is UY, then the actual velocity U
y can be ignored, and the velocity Ux is only in the horizontal direction.

In addition, since the nozzles (26m) to (26e) are located on the same plane as the liquid level (2a), the jet flow is caused by the liquid level (2a) in the tank (1).
2a) Contact with nearby slurry (2). At this time, a fluid with a horizontal velocity Ux comes into contact with a stationary liquid, and a fluid with high viscosity comes into contact with a liquid with a slightly lower viscosity. A transition from a discontinuous surface to a laminar diffusion layer between the discontinuous surface and the slurry (2) near the liquid level (2a) in the tank (1) occurs immediately, and as the jet flow energy is sequentially dissipated, fine coal particles are gradually transferred to the tank. It is mixed into the inner slurry (2). In this way, when these operations are continued for a certain period of time, the slurry (2) in the tank (1) becomes uniform in concentration.

In particular, in this distributor (2G), straight pipes (22m) to (22b) are connected to nozzles (26m) to (22b).
Since the slurry (2) is supplied from the center of the nozzle, the flow of the slurry (2) is smooth and the pressure loss can be minimized. ) to (26e) also become uniform.

According to the inventor's experiments, the coal particle concentration in the tank (slurry (2) in 11) after a certain period of time 111 has passed is
Since the changes are as shown in the figure, the slurry is circulated back to the part of the tank (1) where the concentration of coal particles is the leanest due to the jet flow.

FIG. 6 is a plan view of another distributor of the present invention.

The distributor (30) has pipes (30a) to (Roe) arranged at approximately equal angles and communicates with the circulation pipe (8) at the center. And nozzles (32a) to (32
c) is provided at the bottom of each pipe (30m) to (30a). Figure 7 is a partial cross-sectional view of the pipe (30b), in which a nozzle (32m) bent into an L-shape is provided, and the spout (34a) of the nozzle (32m) is approximately flush with the liquid level (2a). and is open horizontally. However, the pipes (30m) to (30c) themselves are located above the liquid level (2a).

When the slurry (2) is circulated using the distributor (30) in the same way as the distributor (20) in FIGS. 2 and 3 described above, each pipe (30m) to (30e) The jet stream ejected from the nozzles (32a) to (32c) is
It flows horizontally with the liquid surface (2a). And the jet streams are arrows B and C.

Even if it draws a curve like D and flows for a long time, it will pass under the adjacent pipes (30m) to (30e). Therefore,
Even if the jet flow becomes large, the distributor (2
It does not collide with the adjacent pipes (30m) to (30e) as in G) and generate downward velocity Uy and energy.

In particular, in order to circulate the slurry (2) in the tank (1).

In addition to slurry characteristics such as concentration and viscosity of slurry (2),
The circulation amount and circulation time are determined according to the retank capacity.

According to the inventor's experiments, in order to circulate high viscosity CWM slurry, a large tank (1) used industrially requires 1
For example, 2m from one nozzle (32m) to (32e)
When the liquid is ejected at a speed higher than 1/sec, the ejected flow is forcefully ejected in the horizontal direction, causing the liquid level (2a) to move toward arrow B in Figure 6.
, C, and D, and the energy is attenuated. Therefore, the nozzles (32a) to (32c) are arranged in such a way that a jet flow with a flow velocity as shown in FIG.
All you have to do is determine the diameter of the . Also, even if the jet stream flows as shown in Fig. 6, a distributor (3) is installed as shown in Fig. 7 to prevent collisions on the way.
The pipes (30a) to (30c) of 0) may be disposed above the liquid level (2a).

FIG. 8 is a partial cross-sectional view showing another configuration of the nozzle provided in FIG. 36m) was installed in the horizontal direction.

FIG. 9 shows pipes (30a) to (3) of the distributor (30).
0e) is an explanatory diagram showing another aspect of the shape of the tip. In this distributor (30), pipes (30a) to (3
Since each tip of the pipe (0c) also functions as a nozzle, the amount of ejection is large (in this case, the tip of the pipe and the nozzle (3)
Since it is necessary to eject from the pipes (30m) to (32e) and (35a) with an appropriately distributed ejection amount, the diameter of the tip of the pipes (30m) to (30e) is determined in consideration of pressure loss.

In addition, when the pipes (30m) to (3Qe) are arranged above the liquid level (2a) and the jet ports (34a) and (36a) are located at the liquid level (2a), the nozzle is as shown in Fig. 7. It is not limited to the one shown in FIG. 8, and any suitable shape can be adopted. Pipe (30a) ~ (30e
) need not be three, and may be one long pipe or three or more pipes. In addition, the nozzles (32a) provided in the pipes (30a) to (30e)
~(32e).

(34m) and (36m) are pipes (30a) to (3
0e), but each nozzle (
Since the distances between the nozzles (32m) to (32e) and the side wall of the tank (1) are different, if the angles of the nozzles (32a) to (32e) are the same, if the jet stream flows for a long time, the distances from the side wall of the tank (1) will be different.
The conditions for collision with the side wall of the jet stream are different for each jet stream. Therefore, the distance at which the energy of each jet flow is attenuated is different, and the jet flow does not flow in a distributed manner over the entire liquid surface (2a), but each jet flow contacts in the middle and the flow energy flows downward. may be suitable. Therefore, each nozzle (32a) to (
The angles of 32e), (34a), and (36a) may be changed as appropriate so that the jet flow is distributed over the entire liquid surface.

FIG. 10 is an explanatory diagram showing another embodiment of the present invention, in which a nozzle (So) and a swivel joint (51) are provided on the wall of the tank (11), and a pipe (52) is connected to the swivel joint (51). A distributor (2) is connected to the tip of the pipe (52).
G) 1. Attach the center part of (30) and make it communicate,
The slurry (2) extracted from the bottom of the tank (1) is
Distribution Wff through nozzle (5G), swivel joint (51) and pipe (52) by pump (10m)
1, is ejected from (30) onto the liquid surface (2a) of slurry 〇). Even if the liquid level (2a) falls to the position of sign (A>), by rotating the swivel joint (51), the position of the distributor (30) is adjusted to the liquid level (2a).
The distributor ■ follows.

(30) and the liquid surface (2a) can always be located on substantially the same plane or in the vicinity.

〔Effect of the invention〕

As explained above, in this invention, the C of the tank is
Even if the OM or CWM slurry is highly concentrated, coal particles can be mixed throughout the tank slurry and the! of the tank slurry! ! There is no need to form a flow path in the tank, and the slurry concentration in the tank can be easily uniformized in a short time even in a large tank.

[Brief explanation of drawings]

Figure 1 is an explanatory diagram of a tank that is an example of this research, Figure 2
The figure is a plan view of the distributor in Figure 1, Figure 3 is a partial sectional view of the distributor in Figure 2, Figure 4 is a diagram showing the relationship between coal particle concentration and apparent viscosity of slurry in CWM, Figure 5 is
A diagram showing the coal concentration of the slurry in the tank, FIG. 6 is a plan view of another distributor used in this invention, FIGS. 7 and 8 are partial cross-sectional views of the distributor, and FIG. 9 is a diagram of the distributor. FIG. 10 is an explanatory diagram of a device for making a distributor follow the liquid level of slurry in a tank, and FIG. 11 is an explanatory diagram of a conventional tank. In the figure, (1) is a tank, (2) is a slurry, and (2) is a tank.
a) is the liquid level, (4) is the rotating slurry collector, (6) is the agglomeration mixer, (8) is the slurry circulation pipe, (1)
0a) is the pump, (20) and (30) are the distributors, (
30m) ~(30e) is a vibrator, (32m) ~(3
2e), (32m), (35m) are nozzles, (
51) is a swivel joint. Agent Patent Attorney Tadashi Sato Figure 1 Figure 2 Figure 3 Figure 4 G'lA Grain 8J @ (wt '/,) □No. 5
Figure - Back 1 Standing concentration Figure 6 Figure 10 Figure 11 a

Claims (1)

[Claims] Coal-oil slurry (COM) or coal-water slurry (C
(a) a means for extracting the slurry from the bottom of the tank; (b) a means for circulating the slurry extracted by the extractor; and (c) one or more pipes in a plane. and a distributor provided with a plurality of nozzles in the pipe, the openings of the nozzles being located at least on the same plane as, or in the vicinity of, the liquid level of the slurry in the tank; Thriller tank featuring.