JP3332760B2 - Absorbent regeneration and recovery system in flue gas desulfurization system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for regenerating an absorbent Mg (OH) ₂ (hereinafter, referred to as a water mug) from desulfurization wastewater by a magnesium hydroxide method (hereinafter, referred to as a water mug method), and producing CaSO as a by-product. ₄ · 2H ₂ O (hereinafter, referred to as gypsum.) to the reaction crystallizer for generating, on water mug regeneration recovery system having a sedimentation classification apparatus for classifying and the water mug and <br/> gypsum dihydrate .

[0002]

BACKGROUND OF THE INVENTION Apparatus and recycled water mug recovery system to reform water mug is absorbent SO _X from desulfurization effluent of performing flue gas desulfurization by the water mug method, no conventional. However, since the present invention also uses a reaction crystallization apparatus, a conventional reaction crystallization apparatus is shown in FIGS. FIG. 7 is a schematic longitudinal section of the reaction crystallization apparatus, and FIG. 8 is a plan view of FIG. In these figures, an undiluted solution flows in from a supply port 101 and a propeller 10
By 2, an ascending flow 104 is generated in the draft tube 103, thereby causing a circulating flow in the liquid in the apparatus, thereby uniformly stirring the stock solution throughout the apparatus and performing reaction crystallization.

The upward flow 104 in the draft tube 103
Has a swirling component, and in a state where a swirling flow is present, the power required for sucking the liquid 105 into the draft tube 103 increases. Therefore, a rectifying plate 106 is provided to cancel the swirling component. . Also, the discharge hole 10
Numeral 7 is used to drain the liquid in the apparatus during maintenance and inspection.

[0004]

However, in the above-mentioned conventional reaction crystallization apparatus, as shown in FIGS. 7 and 8, the propeller 102 and the draft tube 103 are considerably large with respect to the tower diameter of the apparatus. The required power and torque required to disperse gypsum were very large and costly. Draft tube 1
03 and the bottom portion 108 are considerably separated, so that the bottom portion 1
The dihydrate gypsum deposited at 08 could not be lifted. Further, the flowing water 1
There was a problem that the bumper 11 collided and caused disturbance.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide an absorbent regeneration / recovery system which requires a small amount of power and torque and is inexpensive.

[0006]

SUMMARY OF THE INVENTION The present invention has been made to solve the above object, the gist, hydroxide
Hydroxidation as absorbent from desulfurization wastewater by magnesium method
Regenerates magnesium (Mg (OH ₂ )) as a by-product
Reactive crystallization to produce gypsum (CaSO ₄ · 2H ₂ O) Te
Separation of the magnesium hydroxide and gypsum in a precipitation apparatus
In the water mag desulfurization method equipped with a sedimentation classifier for recovery,
A system for reclaiming and recovering a collecting agent, wherein the sedimentation classification device
Provides a horizontal flow of liquid containing particles at the top in the settling classifier.
The inlet and outlet of the liquid to be generated and below the horizontal flow
At the upstream and downstream of the horizontal flow
The first sorting room and the second sorting room, and below the first sorting room.
Classified to receive particles settled in the first sorting room
A leg, extending upward from the upper part of the classifying leg and joining the horizontal flow
And the liquid in the second sorting chamber is moved upward into the flow path.
Means for blowing toward
Of the mixed slurry of gypsum and gypsum from the reaction crystallizer
Flow into the classifier through the above inlet, and
Gypsum is settled in the first sorting room, and small particle size hydroxy
Configured to settle magnesium iodide into the second sorting chamber
That is. In addition, the recycling and recovery system according to the present invention
In one embodiment, the reaction crystallization apparatus includes a draft tube.
Extend the probe to near the bottom of the reaction crystallizer, and
Attach a current plate under the tube and swirl into the reaction crystallizer
The current is generated. Further according to the invention
In another aspect of the reclaim system, the draft tube
Place a cone on the inside bottom of the tube and at the junction
A guide plate is provided.

[0007]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing the structure of a recycling system according to the present invention .
The reaction crystallization apparatus will be described in detail. FIG. 1 relates to the present invention.
FIG. 2 is a schematic longitudinal cross-sectional view of a reaction crystallization apparatus constituting the regeneration and recovery system , FIG. 2 is a plan view of FIG. 1, and FIG. 3 is a side view of FIG.

In FIG. 1, by rotating a propeller 1, an ascending flow 3 is generated in a draft tube 2, and this flow raises gypsum and water mug. In the reaction crystallization apparatus shown in FIG. 1, it is necessary to perform stirring so that the seed gypsum is evenly distributed throughout the reaction crystallization apparatus in order to grow by-product gypsum together with the regeneration of the water mug. Therefore, by providing a bell mouth 4 at the upper end of the draft tube 2, the dihydrate gypsum and the water mug are dispersed throughout the apparatus.

The upward flow 3 has a swirl component generated by the rotation of the propeller 1. If this is used to generate the swirl flow 5 shown in FIG. 2, even if the upward flow 3 generated by the propeller 1 is weak, a reaction will occur. It is possible to prevent the accumulation of gypsum on the bottom portion 6 of the crystallizer. Draft tube 2
Is extended to the vicinity of the bottom part 6. Reference numeral 16 denotes a current plate. As a result, the suction flow rate of the liquid is increased, and the range in which gypsum and water mug can be sucked into the draft tube 2 is widened. Therefore, even if the propeller 1 and the draft tube 2 having diameters considerably smaller than the outer diameter of the apparatus are used, the dihydrate gypsum and the water mug can be dispersed throughout the apparatus, and deposition on the bottom surface 6 can be prevented.

Further, in order to increase the substantial growth rate of gypsum, it is necessary to reduce the wear rate of gypsum and to reduce the power required for stirring. Therefore, the cone 7 is arranged at the bottom in the draft tube 2, whereby the liquids flowing into the draft tube 2 are smoothly merged,
The required power and required torque of the propeller 1 can be reduced. Further, desulfurized wastewater is supplied from the supply port 8 into the draft tube 2, and calcium hydroxide (Ca (O
By supplying H) ₂ ) onto the liquid surface, a local difference in concentration is suppressed, a substantial growth rate of seed gypsum is increased, and reaction crystallization is continuously performed. At this time, Ca (OH)
_A baffle (11) is provided to prevent the powder of ( ₂ ) from flowing out directly to the cutter (10).

The liquid overflowing from the overflow section 12 flows through the shank 10 and flows into a classification device (not shown) at the subsequent stage. The smaller the disturbance at the time of the flow, the better the classification performance. The guide plate 15 is provided at the confluence portion 14 in order to smoothly merge and suppress the occurrence of turbulence. In addition, the current plate 16 is provided below the draft tube 2 and also serves as a support for the draft tube 2. Further, a discharge port 17 is provided at a lower portion of the cone 7.

[0012] Next, will be described in detail operation of the above reaction crystallizer. In FIG. 1, an upward flow 3 is generated in a draft tube 2 by using a propeller 1. By attaching the bell mouth 4 to the upper end of the draft tube 2, the dihydrate gypsum and the water mug lifted by the upflow 3 are dispersed throughout the apparatus. Since the upward flow 3 has a swirl component, the swirl flow 5 is generated by using the swirl component.
By this flow, gypsum plaster deposited on the bottom part 6 can be slid down, and can be put on the flow sucked into the draft tube 2. Since the draft tube 2 is extended to the vicinity of the bottom surface 6, the flow rate of the liquid sucked into the draft tube 2 is increased, and the area where the dihydrate gypsum and the water mug can be sucked in the bottom surface 6 is widened. In addition, a swirling flow is generated in the apparatus by the rectifying plate 16 installed below the draft tube 2.

Further, the cone 7 provided at the bottom in the draft tube 2 can smoothly merge the flows sucked from the surroundings, and the required power and torque of the propeller 1 can be reduced. In addition, confluence part 1
By the guide plate 15 provided in 4, the merging of the running water 13 becomes smooth, and turbulence can be suppressed as much as possible.

Another Embodiment of the Invention Next, a system for regenerating and recovering an absorbent according to the present invention will be described with reference to FIGS. FIG. 4 is a schematic longitudinal sectional view of a reaction crystallization apparatus provided with a sedimentation classifier, FIG. 5 is a plan view of FIG.
FIG. 5 is a side view of FIG. 4. In the drawings, the same parts as those in FIGS. 1 to 3 are denoted by the same reference numerals. In these figures, a sedimentation classifier 18 classifies water mug and gypsum, and a mixed slurry of water mug and gypsum is introduced from an inlet 19 and placed on a horizontal flow 20. Until the horizontal flow 20 flows out of the outlet 21, gypsum gypsum having a large particle diameter is settled in the first sorting chamber 22, and a part of the water mug having a small particle diameter is settled in the second sorting chamber 23, and the remaining water mug is separated. The water mug flows out of the outlet 21 together with the liquid.

The dihydrate gypsum that has settled in the first sorting chamber 22 accumulates on the classification leg 24. The liquid in the classification leg 24 is fluidized with a screw (not shown) in order to prevent the condensed dihydrate gypsum from being compacted, so that the dihydrate gypsum is fluidized and extracted from the particle outlet 25. At this time, due to the fluidization, the dihydrate gypsum comes into contact with each other, the water mug adhering to the surface is released, and floats on the classifying leg upper portion 26. The water mug that has settled in the second sorting chamber 23 is passed through a water pipe 28 together with the liquid using a pump 27 to flow through a second passage 2.
9 and an upward flow 30 is generated. This ascending flow 3
By 0, the water mug floating on the classifying leg upper part 26 and the water mug in the second sorting chamber 23 are lifted to the junction 31,
It is placed on the horizontal flow 20 again and extracted from the outlet 21. Here, since the recovered water mug is reused as an absorbent for SO _X , particularly, the water mug must have high purity and a high recovery rate. Reference numeral 32 denotes a partition plate that partitions the flow path 30 and the first sorting chamber 22.

Next, the operation of the absorbent recovery and recovery system according to the present invention will be described in detail. Sedimentation classifier 18
Then, the water mug flows out of the outlet 21 by the horizontal flow 20 flowing from the inlet 19. On the other hand, gypsum is deposited on the classification leg 24 through the first sorting chamber 22 and is extracted from the particle outlet 25. By making the liquid in the classification leg 24 flow, the gypsums are brought into contact with each other to release the water mug adhering to the gypsum surface and float on the classification leg upper portion 26. Here, the liquid in the second sorting chamber 23 is blown out from the water guide pipe 28 to the flow path 29 by using the pump 27 to generate the upward flow 30, and the water mug floating on the classification leg upper part 26 is combined with the merging part 31. Then, the water mug is placed on the horizontal flow 20 again, thereby improving the recovery rate of the water mug and the purity of the gypsum. Also,
The water mug adhering to the surface of the gypsum is released, and the liquid in the classification leg 24 is caused to flow by a screw or a vibrating membrane (not shown) in order to collect the water mug.

[0017]

As described above, the regeneration and recovery according to the present invention
According to the system , (1) the power required and the torque required for dispersing the particles throughout the apparatus and preventing accumulation on the bottom surface can be reduced, and the cost can be reduced. (2) Water mug, which is an absorbent from desulfurization effluent by the water mug method, can be regenerated with low power and low torque, resulting in low cost. Further, the recovery rate of the water mug can be increased.

[Brief description of the drawings]

FIG. 1 is a schematic longitudinal sectional view of a reaction crystallization apparatus constituting a regeneration and recovery system according to the present invention.

FIG. 2 is a plan view of FIG.

FIG. 3 is a side view, partially cut away, of the reaction crystallization apparatus constituting the regeneration and recovery system according to the present invention.

FIG. 4 is a schematic vertical sectional view of a regeneration and recovery system according to another embodiment.

FIG. 5 is a plan view of FIG. 4;

FIG. 6 is a side view of FIG. 4;

FIG. 7 is a schematic longitudinal sectional view showing a conventional reaction crystallization apparatus.

FIG. 8 is a plan view of FIG. 7;

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI B01D 9/02 619 C01F 5/14 53/77 11/46 Z C01F 5/14 B01D 53/34 125R 11/46 125D (56) References Features JP-A-49-25557 (JP, A) JP-A-53-32469 (JP, A) JP-A-10-66895 (JP, A) JP-B-48-1301 (JP, B1) JP-B-5-54361 ( JP, B2) Japanese Patent Publication No. 55-23771 (JP, B2) Japanese Patent Publication No. 56-17123 (JP, B2) Japanese Utility Model Publication No. 41-22547 (JP, Y1) Japanese Utility Model Publication No. 3-34243 (JP, Y2) (58) ) Surveyed field (Int.Cl. ⁷ , DB name) B01D 9/02 B01D 53/34

Claims (3)

(57) [Claims] 1. Magnesium hydroxide (Mg (OH ₂ )) as an absorbent from desulfurized wastewater by the magnesium hydroxide method
Play the dihydrate gypsum as a by-product (CaSO ₄ · 2H ₂
Water provided with a sedimentation classifier for separating and recovering the magnesium hydroxide and gypsum from the reaction crystallization apparatus for producing O)
It is a regeneration and recovery system for absorbents in the mag desulfurization process.
Thus, the sedimentation classifier causes the particles in the upper part of the sedimentation classifier
An inlet and an outlet for a liquid that generates a horizontal flow of the liquid containing,
Below and above the horizontal flow, upstream and downstream of the horizontal flow
A first sorting room and a second sorting room provided respectively,
Grains set down below the first sorting room and settled in the first sorting room
A classifying leg for receiving a child, and extending upward from an upper portion of the classifying leg
A flow path merging with the horizontal flow, and a liquid in the second sorting chamber.
Means for blowing upward into the flow path, wherein a mixed slurry of magnesium hydroxide and gypsum is allowed to flow from the reaction crystallization device into the sedimentation classification device via the inlet, and The large-diameter gypsum is settled in the first sorting room,
A system for regenerating and recovering an absorbent in a water-magnesium desulfurization method, wherein magnesium hydroxide having a small particle size is settled in a second sorting chamber. 2. The reaction crystallizer according to claim 1, wherein the draft tube is extended to a position near the bottom of the reaction crystallizer, and a rectifying plate is attached to a lower portion of the draft tube to generate a swirling flow in the reaction crystallizer. Claim 1 characterized by the following:
Recovery and recovery system for water mag desulfurization method described in
M 3. Place the cone on the inside bottom of the draft tube, and you water mug desulfurization method according to claim 1 or 2, characterized in that a guide plate to confluent portion of the gutter
Absorbent recovery system.