JPH0675649B2 - Circulating fluidized bed equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention is a novel method of bringing a stock solution and a medium particle into contact with each other, and adsorbing or adhering to a particle a dissolved substance or a useful substance, a harmful substance and the like, and separating and removing them. The present invention relates to various circulating fluidized bed devices and can be used in the following fields.

(1) Pollutant components (BOD, C) in sewage, night soil and industrial wastewater
Removal of OD, chromaticity, and other components).

(2) Removal of harmful components (iron, manganese, trihalomethanes, organic substances, etc.) from tap water and drinking water.

(3) Recovery of valuables (uranium, etc.) in seawater (4) Purification of liquids in the chemical and food industries, recovery of valuables in liquids.

[Conventional technology]

As a method of separating a dissolved substance, a useful substance, a harmful substance, etc. in a liquid by adsorbing and adhering with a particle medium, there are three known systems, a fixed bed system, a fluidized bed system and a circulating fluidized bed system.
Among them, the fixed bed method has a problem that clogging and pressure loss are large, and the fluidized bed method has a problem that particles are washed away. It has the drawback of requiring a small and vast floor area. In particular, when the concentration of the substance to be treated in the liquid is low, effective contact between a large amount of liquid and the adsorbent is required, and improvement of the linear flow velocity has become a major issue.

In recent years, a particle circulation type fluidized bed (abbreviated as a circulating fluidized bed method) has been proposed in an attempt to solve the drawback. This method is an epoch-making method in which the linear flow velocity can theoretically be operated at a speed higher than the sedimentation velocity of particles, but in reality, the sedimentation and deposition of particles occur inside the tank, and the particles do not circulate uniformly throughout the whole. There is a problem that some of the particles may fly out, and some of the liquid may go around and some may be short-circuited.

[Problems to be Solved by the Invention]

As described above, the known technique has various problems regardless of which method is adopted, and it is not satisfactory as a technique for separating using a particle medium.

An object of the present invention is to solve the above-mentioned problems in the circulating fluidized bed system and to develop a circulating fluidized bed apparatus which can be stably operated at a linear flow velocity higher than the sedimentation velocity of particles.

[Means for Solving the Problems]

As a result of earnest studies to achieve the above-mentioned object, the inventors of the present invention have, in a circulating fluidized bed apparatus, partitioned a tank into an upflow section and a downflow section, and provided a partition wall whose lower end is separated from the tank bottom. The inventors have completed the present invention by finding that by providing the stock solution inlet in the lower part of the tank so as to be connected to the ascending flow part, it is possible to stably operate at a linear flow velocity higher than the sedimentation velocity of particles.

That is, the present invention is a circulating fluidized bed apparatus for adsorbing a dissolved substance, a useful substance, a harmful substance, etc. in a liquid by a particulate medium, and separating them by adhesion, in the tank, the upper end is below the liquid surface and the lower end is the tank. A partition wall separated from the bottom divides the particulate medium into an upward flow portion and a downward flow portion, and a guide plate is formed above the upward flow portion and a separation portion is formed above the downward flow portion. The side wall of the lower part of the tank is inclined linearly or curvedly toward the lower end side of the partition wall, and the lower side wall of the tank on the side of the downward flow part is formed so as to form a moving layer of the particulate medium in the downward flow part. The outlet side for injecting the particulate medium to the ascending flow portion is formed by the side wall of the lower portion of the tank and the lower end of the partition wall, and the stock solution is made to flow into the ascending flow portion in a substantially horizontal direction below the outlet port. Circulating fluidized bed equipment with raw liquid inlet and processing liquid outlet at the top of the tank To.

Next, the present invention will be described in more detail.

In the above apparatus, the partition wall that divides the ascending flow section and the descending flow section of the circulation flow tank may have any shape. For example, a simple plate may be used, but in this case, it is preferable to provide a tongue-shaped portion at the lower end of the partition wall so that the stock solution smoothly flows in from the stock solution inlet and prevents backflow. As for the shape of the partition wall, a slope with the inlet side as the lower end is provided at the lower end so that the undiluted solution smoothly flows in, or the upper part of the partition wall is inclined toward the descending flow part to descend the particles. It can be in the shape of promoting.

The guide plate provided above the ascending flow portion may be of any shape and size as long as it promotes circulation of the ascending flow. In addition, it is preferable to provide a particle separation plate near the upper boundary between the separation part and the downflow part in order to promote separation of particles.
The shape of the separating plate is preferably provided so that the mixed liquid having passed over the partition wall collides with the separating plate to capture particles.

The lower side wall of the circulating flow tank on the downflow section side must be inclined toward the lower end of the partition wall so as to form a moving layer of the particulate medium in the downflow section, and the lower side wall on the upflow section side. It is advisable to install so that the inflow of the undiluted solution from the undiluted solution inlet smoothly proceeds and no dead space is generated.

Further, in the design of the device according to the present invention, in order to form a turbulent state in the upflow portion, the width of the stock solution inlet is preferably 1/5 to 1/20 of the upflow portion width, The width of the part is 2/3 to 1/5, preferably 1/2 to 1/4 of the total width.

Various adsorbents and adhesives can be widely used as the particle medium that can be used in the present invention. For example, activated carbon, silica particles, activated alumina, bone charcoal, glass beads, ion exchange resin, sand, PA-based granulated hydrous titanium oxide and the like are used.

Further, in the present invention, in order to suppress the accumulation of particles in the upflow portion, the upflow portion particle volume concentration in the upflow portion is about
It is preferable to operate in the range of 0.1 to 0.3, and the flow velocity in the ascending section should be in the range of about 1.5 to 2.0 times the particle group sedimentation velocity.

The particulate medium used in the present invention can be recycled by reusing it by extracting a part of it, and further, the apparatus of the present invention can be connected in multiple stages to treat a stock solution that cannot be sufficiently treated in a single stage treatment, and a series of treatment steps. It can also be incorporated as one of.

[Work]

In the circulating fluidized bed apparatus of the present invention, the stock solution inlet is located at the bottom of the tank, and since the stock solution is ejected from the narrow inlet width toward the particle ascending flow part, the particles are discharged from the particle outlet at the upper part. Is mixed in and rises in the ascending flow section while forming a vortex, during which uniform and sufficient mixing and solid-liquid contact are performed in a turbulent state, and the undiluted solution is processed.

Therefore, the membrane resistance on the surface of the particles is small, the adsorption speed is high, and the adsorption is uniform, and the adsorption efficiency of the particles is good. Further, there is no leakage of the stock solution, and a high treatment effect can be obtained.

The ascended particle suspension flows down as a density flow to the descending flow part through the separating part on the opposite side at the upper part of the partition plate. The downflowing density flow collides with the deposited particles in the downflow part, and the particle group in the density flow is captured. On the other hand, the treatment liquid is inverted here and separated from the particles, rises again, and is discharged from the outlet. Since the particle groups flow down in a density flow and are separated, they are separated at high speed and efficiently.

The separated particles move down in the descending flow section, and come down again to come into contact with the stock solution at the particle outlet. Since the particles circulate, there is no need to worry about the particles flowing out, and the adsorption capacity can be fully utilized. Moreover, since the particle group is in a fluid state and is in a strong mixing field, there is no attachment of SS particles or clogging.

〔Example〕

The present invention will be specifically described below with reference to the drawings, but these drawings merely exemplify the embodiments of the present invention.

Example 1 FIG. 1 is a schematic diagram showing a circulating fluidized bed apparatus which is the basis of the present invention. In FIG. 1, the stock solution to be treated flows in from the stock solution inlet 1, mixes the particles from the particle outlet 7 at the lower end of the downflow section 4, and moves to the upflow section 3 while being mixed. Here, the stock solution comes into contact with the particles while forming a vortex, and the target substance in the solution is removed by the action of physical adsorption, chemical reaction, or the like. Since the undiluted solution has very good contact with particles, reactions such as adsorption proceed uniformly in a very short time, are processed, and have no leak.

The treatment liquid and particles that have reached the upper end of the ascending flow portion do not rise upward as they are due to the action of the partition wall 5 and the guide plate 8 and form a density flow toward the descending flow portion 4 beyond the upper end of the partition wall. Flow down.

On the other hand, the treatment liquid collides with the wall of the particles accumulated in the downward flow portion, is inverted, becomes an upward flow again, and is guided to the treatment liquid outlet 2 via the separation unit 6. Since the particles are collided and captured as a density flow, the separation speed is high and the separation efficiency is good. In the conventional fluidized bed, the separation velocity is affected by the interference sedimentation and a linear flow velocity slower than the sedimentation velocity of a single particle has to be used as the separation velocity. It can be operated at linear flow velocity.

The descended particles collide with particles already accumulated in the descending flow portion, are captured, become a part of the accumulated particle group, and are circulated and reused. The shape of this part is important because particles are likely to accumulate in the dead space near the outlet and easily mix with the undiluted solution and flow away, and at the same time backflow occurs in the downflow part. The lower end of the partition wall 5 has a tongue portion 9 for preventing backflow.
Is provided.

In FIG. 1, if the specific shape of the device is shown,
The relationship between the stock solution inlet width Li and the rising flow width Lc is Li / Lc = 1/5 to 1 /
20 is good, and the relationship between the ascending flow width Lc and the total width L _T is Lc / L _T = 2 / 3〜
1/5 is preferably 1/2 to 1/4, and the relationship between the partition height, that is, the height of the filling particles and the liquid level is H _N H _O <H _T. FIG. 2 shows a liquid flow state diagram in the actual operation.

Embodiments 2 to 7 FIGS. 3 to 7 and 10 are schematic views of a circulating fluidized bed apparatus showing another embodiment of the present invention.

Example 2 is shown in FIG.

The present embodiment has the effect that the slope of the rising portion of the rising portion is formed in a curved shape instead of a straight shape, and the horizontal flow of the undiluted solution becomes a smooth upward flow without resistance.

Example 3 is shown in FIG.

In this embodiment, the shape of the partition wall 5 is different, and the upper part of the partition wall is inclined toward the downward flow part side and the lower part is inclined toward the upward flow part. The upper part of the partition wall has the effect of promoting the downward movement of particles, and the lower part has the effect of promoting the upward movement.

Example 4 is shown in FIG. In the present embodiment, the separation portion of the fluidized bed is wide, and the separation of particles is further improved.

Embodiments 5 and 6 are shown in FIGS. 6 and 7. In this embodiment, the particle separating plate 10 is provided near the boundary between the downflow part and the separating part. By providing this particle separating plate, the colliding particles are prevented from being ejected by the repulsive force, and the upward flow of the processing liquid is rectified to improve the separation of the particles.

8 and 9 show a specific example of the particle separation plate 10 as a partially enlarged schematic view.

Example 7 is shown in FIG. In the present embodiment, the cross-sectional shape of the raw liquid inlet is reduced toward the tip, and since the liquid flow is strengthened, the particles can be uniformly mixed and raised.

〔The invention's effect〕

As described above, the following effects can be obtained by using the circulating fluidized bed apparatus of the present invention.

(1) Since the linear velocity of the ascending flow portion is set to be equal to or higher than the sedimentation velocity of the particles, the particles and the liquid are well mixed and the adsorption reaction rate is high.

(2) Due to the structure in which the undiluted solution inflow velocity can be made higher than the ascending velocity, there is no particle deposition or deposition due to the particle entrainment effect.

(3) Since the downward flow part of particles also serves as a storage part, there is no backflow of the inflow liquid.

(4) The total amount of the mixed liquid containing the particles that have risen turns around 180 degrees, and descends at the same flow velocity as the linear velocity at the time of rise.
High speed separation. Although the theory of such a phenomenon has not been fully clarified, if the structure according to the present invention is adopted in an appropriate flow velocity range, the mixed liquid containing particles takes an integral action and is bent by the upper resistance and the self-weight of the mixed liquid. , Shows a phenomenon similar to density flow. At this time, a negative pressure is generated around the mixed liquid. Therefore, the particles are prevented from jumping out, and the particles collide with the filling portion and are effectively trapped in the filling portion due to the inertial effect.

(5) Large-scale processing, continuous processing, and high-speed processing are possible, the device can be made compact, and the facility area can be reduced.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a circulating fluidized bed apparatus which is the basis of the present invention, FIG. 2 is a liquid flow state diagram, and FIGS. 3 to 7 are schematic diagrams showing other embodiments of the present invention. , FIG. 8 and FIG. 9 are partially enlarged schematic views of the particle separation plate used in the present invention, and FIG. 10 is a schematic view showing another embodiment of the present invention. 1 ... Undiluted solution inlet, 2 ... Treatment solution outlet 3 ... Upflow part, 4 ... Downflow part 5 ... Partition wall, 6 ... Separation part 7 ... Particle outlet, 8 ... Guide plate 9 ... tongue, 10 ... particle separator

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-51-5270 (JP, A)

Claims (2)

[Claims] 1. A circulating fluidized bed apparatus for separating a dissolved substance, a useful substance, a harmful substance, etc. in a liquid by adsorbing and adhering with a particle medium in a tank, wherein the upper end is below the liquid surface and the lower end is the tank bottom. The partition wall is separated from the upward flow portion and the downward flow portion of the particulate medium, and a guide plate is formed above the upward flow portion and a separation portion is formed above the downward flow portion. The side wall of the lower part of the tank is inclined linearly or curvedly toward the lower end side of the partition wall, and the lower side wall of the tank on the side of the downward flow part is formed so as to form a moving layer of the particulate medium in the downward flow part. The outlet side for injecting the particulate medium to the ascending flow portion is formed by the side wall of the lower portion of the tank and the lower end of the partition wall, and the stock solution is made to flow into the ascending flow portion in a substantially horizontal direction below the outlet port. A circulating fluidized bed apparatus in which a stock solution inlet is opened and a processing solution outlet is opened at the upper part of the tank. 2. The circulating fluidized bed apparatus according to claim 1, wherein a particle separating plate is provided in the descending flow section.