WO2012127689A1

WO2012127689A1 - Flue gas desulfurization apparatus

Info

Publication number: WO2012127689A1
Application number: PCT/JP2011/057227
Authority: WO
Inventors: 昭雄吉越; 昭浩本間
Original assignee: 月島機械株式会社
Priority date: 2011-03-24
Filing date: 2011-03-24
Publication date: 2012-09-27

Abstract

[Problem] To prevent pressure fluctuation inside an absorption tower due to fluctuation of the water level in a sea water channel, and to prevent fluctuations in and the reduction of desulfurization efficiency. [Solution] A flue gas desulfurization apparatus in which a gas (FG) and seawater (SW) which serves as an absorption liquid are brought into contact with each other in an absorption tower (1) and sulfur oxidizing matter in the gas is absorbed and removed, wherein the following are provided: an absorption liquid storage unit (7) provided within and at the bottom of the absorption tower (1); a barrier (8) that is provided at the wall part of the absorption liquid storage unit, over which the seawater flows; a seawater channel (10) provided below the absorption tower or below an area adjacent to the absorption tower (1); and an absorption liquid guide part (9) that guides sea water which has flowed over the barrier (8) to flow through a free space down to the surface of the water in the seawater channel (10). A water discharge port (13) of the absorption liquid guide part (9) communicates with the seawater in the seawater channel (10); the free space is separated from outside air.

Description

Flue gas desulfurization equipment

The present invention relates to flue gas desulfurization equipment, and more specifically, for example, exhaust gas discharged from combustion exhaust gas of power generation equipment and seawater are contacted in an absorption tower, and sulfur oxides in the exhaust gas are absorbed into seawater and removed. The present invention relates to a flue gas desulfurization apparatus.

For example, since the combustion exhaust gas discharged from the power generation facility contains sulfur oxide, it is necessary to remove the exhaust gas before discharging it into the atmosphere. As equipment for removing sulfur oxides from exhaust gas, spray-type absorption towers, Moretana-type absorption towers, packed tower-type absorption towers and the like are generally known. Among these facilities, the Moretana type absorption tower is a device that uses a perforated plate (moretana) to remove the sulfur oxide in the exhaust gas by bringing the exhaust gas into contact with the absorbing solution on the perforated plate. Moretana type absorption towers have the advantage of higher sulfur oxide removal performance than other absorption towers.

As the absorption liquid used in the above-mentioned Moretana type absorption tower, those using magnesium hydroxide, seawater, sodium hydroxide, etc. are generally known. The method of using seawater in these absorbing liquids has the advantage that there are no by-products compared to other methods and can be discharged to the sea after aeration.

Examples of the Moretana type absorption tower include the following Patent Document 1. That is, for example, the combustion exhaust gas discharged from the power generation facility comes into contact with seawater as an absorption liquid on a perforated plate provided in the absorption tower, and sulfur oxides in the exhaust gas are removed. The exhaust gas from which the sulfur oxide is removed passes through the exhaust port of the absorption tower and is exhausted into the atmosphere.
On the other hand, the absorbing solution that has absorbed the sulfur oxide descends downward in the absorption tower, and is mixed with fresh seawater in the seawater channel and aerated, and then discharged to the sea.

It is also known to use a packed tower type absorption tower. The packed tower type absorption tower has a structure in which a packing material is packed in the absorption tower. For example, the combustion exhaust gas discharged from the power generation facility comes into contact with seawater as an absorption liquid while passing through the packing provided in the absorption tower, and sulfur oxides in the exhaust gas are removed. On the other hand, the absorption liquid that has absorbed sulfur oxides descends downward in the absorption tower, and is mixed with fresh seawater in the seawater channel and aerated, and then discharged to the sea.

JP 2008-200261 A

In the Moretana type absorption tower, the seawater descending from the upper side and the exhaust gas rising from the lower side make countercurrent contact on the Moretana. By mixing seawater and exhaust gas on the Moretana, sulfur oxides in the exhaust gas are removed. Further, in the packed tower type absorption tower, seawater descending from above and exhaust gas rising from below are in countercurrent contact on the surface of the packing. In order to prevent the exhaust gas from diffusing to the outside air, the inside of the absorption tower is generally airtight with respect to the seawater channel.
The present inventors have found that it is necessary to keep the pressure in the absorption tower substantially constant at a predetermined pressure in order to efficiently contact seawater on the Moretana or on the surface of the packing. In addition, when the sea level fluctuates, the pressure in the absorption tower will fluctuate, and the contact state between the exhaust gas and seawater on the surface of the Moretana or the packing, which directly affects the desulfurization efficiency, varies. It has been found that the efficiency varies and decreases.

Therefore, the main problem of the present invention is to suppress fluctuations in pressure in the absorption tower due to fluctuations in the water level of seawater channels, etc., and to prevent fluctuations and declines in desulfurization efficiency.

As the present invention according to claim 1 for solving the above-mentioned problem, in the flue gas desulfurization apparatus for contacting the seawater as the exhaust gas and the absorption liquid in the absorption tower to absorb and remove sulfur oxides in the exhaust gas,
An absorption liquid reservoir provided in the lower part of the absorption tower;
A weir that overflows the absorbent provided in the wall of the absorbent reservoir;
A seawater channel provided below the absorption tower or near the absorption tower;
An absorption liquid guiding section for guiding the seawater that has passed through the weir to flow down in a free space on the surface of the seawater channel, and
The absorption liquid guiding portion has a drain port communicating with the seawater in the seawater channel, and the free space is isolated from the outside air,
A flue gas desulfurization apparatus is provided.

(Function and effect)
Seawater, which is an absorbent, overflows from a weir provided on the wall of the absorbent reservoir. Next, the seawater is guided by the absorbing liquid guiding section so as to flow down in the free space on the water surface of the seawater channel. As for this absorption-liquid induction | guidance | derivation part, the drain outlet is connected in the seawater in a sea channel, and the said free space is isolated with the external air. As described above, the absorption liquid storage section is cut off from the free space via the weir, so that the pressure fluctuation in the absorption tower is suppressed even if the sea level changes. As a result, fluctuations in the contact state between the exhaust gas and seawater in the absorption tower are reduced, and fluctuations and declines in desulfurization efficiency can be suppressed.
On the other hand, since the drainage port of the absorbing liquid guiding part communicates with the seawater in the seawater channel, the internal free space is isolated from the outside air. As a result, the treated exhaust gas is not exhausted from other than a predetermined position (upper column).

As the present invention according to claim 2 for solving the above-mentioned problem, flue gas desulfurization according to claim 1, wherein contact between the exhaust gas and seawater is made on a perforated plate provided in the absorption tower. An apparatus is provided.

(Function and effect)
In the Moretana type absorption tower, fluctuations in the contact state between the exhaust gas and seawater on the perforated plate (Moretana) that directly affects the desulfurization efficiency can be prevented, and as a result, fluctuations and declines in the desulfurization efficiency can be suppressed.

According to a third aspect of the present invention for solving the above-described problem, the absorption tower is provided on a side of the seawater flow direction of the seawater channel in a plan view, and the absorption liquid guiding portion extends from the absorption tower to the seawater channel. The flue gas desulfurization device according to claim 1, which extends in a direction, and a drain outlet of the absorption liquid guiding portion communicates with seawater in the seawater channel.

(Function and effect)
Since the absorption liquid (seawater in contact with the exhaust gas) from the absorption liquid guide part flows into the seawater channel from the absorption tower from the side, the absorption liquid (seawater in contact with the exhaust gas) and seawater ride on the seawater flow. Stirring and mixing with As a result, stirring and mixing are performed efficiently.
It can also be considered that the absorbing liquid guiding portion is arranged so as to extend from the upstream to the downstream of the flow of seawater. However, it is necessary to perform piping for the absorption liquid guiding portion in the basement under the sea channel, resulting in a structure in which equipment costs increase and maintenance is difficult. On the other hand, if the absorption tower is provided at the side of the seawater flow direction of the seawater channel and the absorption liquid (seawater in contact with the exhaust gas) flows from the side into the seawater channel from the absorption tower, the absorption liquid induction A small installation cost is sufficient.
Further, by constructing the absorption tower on the side of the seawater channel, the construction cost is sufficient as compared with the case of constructing the absorption tower on the seawater channel.

According to a fourth aspect of the present invention for solving the above-mentioned problem, the absorption tower is substantially provided on the seawater channel in a plan view, and the absorption liquid guiding portion extends in a radial direction from the absorption tower. The flue gas desulfurization device according to claim 1, wherein the flue gas desulfurization device extends to the upstream side of the seawater flow of the seawater channel, and a drain port of the absorption liquid guiding part communicates with seawater in the seawater channel. The

(Function and effect)
If an absorption tower is installed on the sea channel mainly from the viewpoint of securing space, the construction cost will increase, but on the other hand, extending the absorption liquid guiding part to the upstream side of the sea water flow in the sea channel is a layout. It is easy and the construction cost is low. Furthermore, it becomes a thing with a high stirring and mixing effect by making countercurrent contact the absorption liquid (seawater which contacted exhaust gas) and fresh seawater of an absorption liquid induction | guidance | derivation part.

According to the flue gas desulfurization apparatus of the present invention, it is possible to prevent pressure fluctuations in the absorption tower due to fluctuations in the sea level of the seawater channel, and to suppress fluctuations and declines in desulfurization efficiency.

1 is an elevation view of a flue gas desulfurization apparatus according to the present invention. It is an elevational view of another example of the flue gas desulfurization device having a different absorbing liquid guiding part. It is an elevational view of another example of the flue gas desulfurization device having a different absorbing liquid guiding part. It is an elevational view of an example of a flue gas desulfurization device in an example in which an absorption tower is provided on a seawater channel. It is an elevational view of the flue gas desulfurization apparatus according to the present invention when the seawater channel and the absorption tower are separated from each other. It is an elevational view of another example of the flue gas desulfurization apparatus according to the present invention when the seawater channel and the absorption tower are separated from each other. It is a top view of the flue gas desulfurization apparatus of the example which provided the absorption tower in the side of the seawater channel. It is a top view of the flue gas desulfurization apparatus of another example which provided the absorption tower in the side of the seawater channel. It is a top view of the flue gas desulfurization apparatus of the example which provided the absorption tower above the seawater channel. It is a top view of the flue gas desulfurization apparatus of the other example which provided the absorption tower above the seawater channel.

Hereinafter, a preferred embodiment of the flue gas desulfurization apparatus of the present invention will be described with reference to FIGS. Note that the following description of the preferred embodiment is merely an exemplification, and is not intended to limit the application of the present invention or its use.

FIG. 1 is an elevational (sectional) view of a first embodiment of a flue gas desulfurization apparatus according to the present invention.

First, the case where the absorption tower 1 is a moretana type absorption tower will be described. A supply port 2 for supplying exhaust gas (for example, combustion exhaust gas from a waste heat boiler in a power generation facility) FG is provided on the lower side surface of the absorption tower 1. Further, an exhaust port 6 for exhausting the treated exhaust gas TG that has undergone the treatment in the absorption tower 1 is provided on the upper surface of the absorption tower 1.
Further, at the upper part of the absorption tower 1, there are a water supply pipe 3 for introducing fresh seawater SW as an absorption liquid into the absorption tower 1, and a nozzle 4 for injecting the water supply pipe 3 downward in the absorption tower 1. Is provided. In this specification, “fresh seawater” SW is seawater led from the sea, and the sulfur oxide after the absorption treatment performed on the perforated plate 5 in the absorption tower 1 to be described later is used. Differentiated from seawater containing. In addition to the fresh seawater taken directly from the sea as described above, the fresh seawater used from the condenser (condenser) of the boiler facility or the brine discharged from the seawater desalination facility may be used.

Further, for example, a shelf plate group is provided below the water supply pipe 3 and the nozzle 4 of the absorption tower 1, and one or more perforated plates (moretana) 5 having an opening ratio of preferably 25% to 60% are provided. .

The exhaust gas FG supplied from the supply port 2 installed on the lower side surface of the absorption tower 1 moves upward in the absorption tower 1. The exhaust gas FG and the fresh seawater SW sprayed downward from the nozzle 4 provided at the upper portion of the absorption tower 1 are in countercurrent contact on the perforated plate 5 provided in the middle portion of the absorption tower 1. Through the countercurrent contact, the sulfur oxide contained in the exhaust gas is absorbed by the fresh seawater SW and removed from the exhaust gas.
The treated exhaust gas TG from which the sulfur oxide has been removed is exhausted from an exhaust port 6 provided in the upper part of the absorption tower 1. In addition, the seawater that has absorbed the sulfur oxide falls downward in the absorption tower 1.

An absorption liquid storage section 7 is provided in the lower part of the absorption tower 1, and the lowered absorption liquid is temporarily stored in the absorption liquid storage section 7.
A dam 8 is provided on the wall portion of the absorbing liquid storage section 7, and the absorbing liquid stored in the absorbing liquid storage section 7 gets over the weir 8 and flows outward.

In the present invention, in addition to the Moretana type absorption tower, the absorption tower 1 may be a packed tower type absorption tower, and this packed tower type absorption tower will be described. The basic structure is the same as that of the Moretana absorption tower, and is different in that the packing is filled. The packing is supported in the absorption tower by being supported by a perforated plate or a metal net. As the filler, a metal or resin filler is used. The filling is not limited to one stage, and may be a plurality of stages.

Next, the relationship between the absorption tower 1 and the seawater channel 10 will be described. As the absorption tower 1, either a Moretana type absorption tower or a packed tower type absorption tower can be applied.
For example, as shown in FIG. 7 in plan view, the absorption tower 1 is provided on the side of the seawater channel 10 in the seawater flow direction, and an absorption liquid guiding section 9 is provided at the lower part of the absorption tower 1. The guiding portion 9 extends from the absorption tower 1 toward the seawater channel 10.
The absorption liquid that has overflowed the weir 8 flows into the absorption liquid guiding portion 9 from the overflow port 12 and flows down onto the water surface of the sea channel 10 while being guided to flow down in the free space. The drainage port 13 of the absorbing liquid guiding part 9 communicates with seawater in the seawater channel 10. The absorbing liquid guiding portion 9 is formed of, for example, a metal plate and isolates the free space inside from the outside air (atmosphere).

It is preferable that the position of the discharge port 13 of the absorbing liquid guiding unit 9 is at a height below the sea level of the sea channel 10 at any time. When the discharge port 13 is open to the outside air (atmosphere), exhaust gas containing sulfur oxide in the absorption tower 1 may leak out of the discharge port 13. Further, there is a possibility that outside air may enter the absorption tower 1 through the absorption liquid guiding section 9. In order to prevent these problems, the inside of the absorbing liquid guiding portion 9 is isolated from the outside air (atmosphere).

And the seawater channel 10 is made to always flow fresh seawater SW from the upstream to the downstream, and the absorption liquid from the absorption liquid guiding part 9 is caused to flow into the flow. And it discharges to the sea as a treated water through the process in the sea channel 10. As the treatment in the seawater channel 10, typically, (1) the absorption liquid discharged from the absorption liquid guiding unit 9 and fresh seawater SW are agitated and mixed in the seawater channel 10, and the pH of the absorption liquid is increased. A step of recovering the value, and (2) a step of performing an aeration process with the air or oxygen in the seawater channel 10 on the absorption liquid whose PH value has been recovered, and further recovering the PH value. The seawater whose PH value has been recovered after the processes (1) and (2) have been performed is discharged into the sea.
In the above example, the process (2) is performed after the process (1) is performed. However, in the seawater channel 10, the process (1) and the process (2) are performed continuously or simultaneously. You may make it perform.

In such a flue gas desulfurization apparatus, the pipe length of the absorbing liquid guiding section 9 from the absorption tower 1 to the seawater channel 10 can be shortened, so that it is possible to reduce civil engineering costs associated with the piping.

1 shows a case where a metal duct is used as the absorbing liquid guiding section 9, but a reinforced concrete structure 9A may be used as shown in FIG. The absorption liquid does not flow down into the seawater channel 10 as it is in the absorption liquid guiding section 9, but has a portion that flows in the horizontal direction when the absorption tower 1 and the seawater channel 10 are separated as shown in FIG. It is good also as a shape.

As shown in FIG. 4, when the installation space does not allow, the absorption tower 1 can be provided above the sea channel 10. In the illustrated example, the absorption tower 1 is provided on the seawater channel 10 using the seawater channel 10 as a structure. The absorbing liquid that has dripped over the weir 8 from the absorbing liquid storage section 7 in the absorption tower 1 flows down through the absorbing liquid guide section 9 and the downflow path 9B, and then flows down onto the seawater path 10.

In some cases, the absorption tower 1 cannot be provided in the vicinity of the seawater channel 10 due to facility layout design. In this case, as shown in FIG. 5 and FIG. 6, the absorption liquid overflowing the weir 8 from the absorption liquid storage section 7 in the absorption tower 1 is supplied to the seawater channel 10 provided at a location a little away through the guide path 9 </ b> C. You may make it pour.
FIG. 5 shows an example in which the guide path 9 </ b> C is directly connected to the seawater path 10. Moreover, FIG. 6 has shown the example which connected the downstream channel 9B with the approach pipe line of the fresh seawater (absorption liquid) SW to the seawater channel 10. FIG.

Next, the planar positional relationship between the absorption tower 1 and the seawater channel 10 will be described with reference to the plan views of FIGS.

7 and 8 are examples in which the absorption tower 1 is installed on the side of the seawater channel 10. 9 and 10 are examples in which the absorption tower 1 is installed above the seawater channel 10. FIG. 9 and FIG. 10 are different in that the entire absorption tower 1 is installed above or part of the seawater channel 10.
The positional relationship between the absorbing liquid guiding unit 9 and the supply port 2 for supplying exhaust gas (for example, combustion exhaust gas from a combustion boiler in a power generation facility) FG is linear as shown in FIG. As shown in FIG. 10, the relationship may be orthogonal.

7 and 8, in the example in which the absorption tower 1 is constructed on the side of the seawater channel 10, the absorption liquid (seawater in contact with the exhaust gas) from the absorption liquid guiding unit 9 is in the seawater channel from the absorption tower 1. Therefore, the agitation and mixing of the absorption liquid (seawater in contact with the exhaust gas) and the seawater gradually proceed along the seawater flow, so that the agitation and mixing are performed efficiently.
In addition, it can be considered that the absorbing liquid guiding part 9 is arranged so as to extend from the upstream to the downstream of the flow of the seawater. In that case, the absorbing liquid guiding part 9 is provided below the seawater channel 10. It is necessary to carry out the piping, which increases the construction cost. On the other hand, the absorption tower 1 is provided on the side of the seawater passage 10 in the seawater flow direction, and absorption liquid (seawater in contact with exhaust gas) flows into the seawater passage 10 from the absorption tower 1 from the side. A small installation cost of the liquid guiding portion 9 is sufficient.
Further, by constructing the absorption tower 1 on the side of the sea channel 10, a construction cost lower than that in the case of constructing the absorption tower on the sea channel 10 is sufficient.

In FIGS. 9 and 10, when the absorption tower 1 is provided on the seawater channel 10 mainly from the viewpoint of securing a space, the construction cost increases. On the other hand, the absorption liquid guiding portion 9 is connected to the seawater channel. It is easy as a layout to extend to the upstream side of the seawater flow, and the construction cost is low. Furthermore, it becomes a thing with a high stirring and mixing effect by making the absorption liquid (seawater which contacted exhaust gas) and the fresh seawater SW of the absorption liquid induction | guidance | derivation part 9 contact countercurrent.

DESCRIPTION OF SYMBOLS 1 ... Absorption tower 2 ... Supply port 3 ... Water supply pipe 4 ... Nozzle 5 ... Perforated plate (Moretana)
6 ... Exhaust port 7 ... Absorbing liquid storage section 8 ...

Weir

9, 9A ... Absorbing liquid guiding section 9B ... Downflow path 9C ... Guide path 10 ... Seawater path 13 ... ·Vent

FG ... exhaust gas)
TG ... treated exhaust gas SW ... fresh seawater (absorbing liquid)
TW ... Discharged water

Claims

In a flue gas desulfurization apparatus that makes exhaust gas and seawater as an absorption liquid contact in an absorption tower to absorb and remove sulfur oxides in the exhaust gas,
An absorption liquid reservoir provided in the lower part of the absorption tower;
A weir that overflows seawater provided on the wall of the absorbing liquid reservoir;
A seawater channel provided below the absorption tower or near the absorption tower;
An absorption liquid guiding section for guiding the seawater that has passed through the weir to flow down in a free space on the surface of the seawater channel, and
The absorption liquid guiding portion has a drain port communicating with the seawater in the seawater channel, and the free space is isolated from the outside air,
A flue gas desulfurization apparatus characterized by that.
The flue gas desulfurization apparatus according to claim 1, wherein the exhaust gas and seawater are brought into contact with each other on a perforated plate provided in the absorption tower.
In plan view, the absorption tower is provided to the side of the seawater flow direction of the seawater channel, the absorption liquid guiding part extends from the absorption tower in the seawater channel direction, and the drainage port of the absorption liquid guiding part is the The flue gas desulfurization apparatus according to claim 1, wherein the flue gas desulfurization apparatus communicates with the seawater in the seaway.
In plan view, the absorption tower is substantially provided on the seawater channel, and the absorption liquid guiding portion extends radially from the absorption tower and extends upstream of the seawater flow in the seawater channel. The flue gas desulfurization apparatus according to claim 1, wherein a drain outlet of the absorption liquid guiding section communicates with seawater in the seawater channel.