PD043219IN-NP
FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See section 10, rule 13)
1. Title of the invention: METHOD FOR MODIFYING LIQUID COLUMN TYPE ABSORPTION TOWER AND LIQUID COLUMN TYPE ABSORPTION TOWER
2. Applicant(s)
NAME
NATIONALITY
ADDRESS
MITSUBISHI POWER, LTD.
Japanese
3-1, Minatomirai 3-Chome, Nishi-ku, Yokohama-shi, Kanagawa 2208401, Japan
3. Preamble to the description
COMPLETE SPECIFICATION
The following specification particularly describes the invention and the manner in which it is to be performed.
1
METHOD FOR MODIFYING LIQUID COLUMN TYPE ABSORPTION TOWER AND LIQUID COLUMN TYPE ABSORPTION TOWER
TECHNICAL FIELD
[0001] The present disclosure relates to a method for modifying a liquid column type 5 absorption tower in which scrubbing liquid is spouted upward in the form of liquid columns to clean exhaust gas, and also relates to a liquid column type absorption tower.
BACKGROUND
[0002] Exhaust gas discharged from a combustion engine such as a boiler contains air 10 pollutants such as SOx (sulfur oxide). As a method for reducing SOx contained in exhaust gas, there may be mentioned a wet desulfurization method in which substances such as SO2 (sulfur dioxide gas) are absorbed and removed by an absorption liquid such as an alkaline aqueous solution or an absorption slurry.
[0003] As a desulfurization device used in the wet desulfurization method, a liquid column 15 type absorption tower in which scrubbing liquid (absorption liquid) is spouted upward in the form of liquid columns to clean exhaust gas is known (see for example, Patent Document 1). In the liquid column type absorption tower, scrubbing liquid injected from the liquid column nozzles forms liquid columns above the liquid column nozzles. After forming the liquid columns, the scrubbing liquid disperses at the top of spout, then falls down, impinges on 20 scrubbing liquid spouted upward from the liquid column nozzles, and thus is atomized into fine droplets. The atomized scrubbing liquid effectively comes into gas-liquid contact with exhaust gas and effectively absorbs air pollutants. Also, the atomized scrubbing liquid can remove soot and dust contained in exhaust gas from the exhaust gas. 25
Citation List
Patent Literature
[0004] Patent Document 1: JPH10-128053A
2
SUMMARY
Problems to be Solved
[0005] In recent years, there has been a trend toward tighter regulations on emissions of air pollutants such as sulfur oxides and soot. One way to reduce emissions of air pollutants is to 5 use high-quality fuel in combustion engines, such as low-sulfur fuel with low sulfur content and low-dust fuel with low amount of dust produced by combustion. However, since the high-quality fuel is expensive, there is a desire to use low-cost fuel such as high-sulfur fuel and high-dust fuel with low amount of dust produced by combustion, in order to reduce the operating cost. 10
[0006] Due to the above circumstances, there is a need to improve the desulfurization and dust removal performance of the existing liquid column type absorption tower. In order to improve the desulfurization and dust removal performance of the existing liquid column type absorption tower, the flow rate of scrubbing liquid delivered to the liquid column nozzle can be increased to raise the height of the liquid column, but if the height of the liquid column is to be 15 raised above the original design height of the column, the height of the main body of the absorption tower needs to be raised. Modification to increase the height of the absorption tower body is a long-term, large-scale project, which may increase the cost of modification. Patent Document 1 does not describe any method for modifying a liquid column type absorption tower. 20
[0007] In view of the above, an object of at least one embodiment of the present invention is to provide a method for modifying a liquid column type absorption tower whereby it is possible to prevent an increase in modification cost and improve desulfurization and dust removal performance. 25
Solution to the Problems
[0008] (1) A method for modifying a liquid column type absorption tower according to at least one embodiment of the present invention is to modify a liquid column type absorption
3
tower including an absorption tower body having an interior space, and a liquid column nozzle disposed in the interior space and configured to inject a scrubbing liquid upward in the form of liquid columns, and comprises: a spraying device addition step of adding a spraying device to a position above the liquid column nozzle, the spraying device being configured to spray a scrubbing liquid downward; and a scrubbing liquid supply line addition step of adding at least 5 one scrubbing liquid supply line for supplying a scrubbing liquid to the spraying device.
[0009] In the liquid column type absorption tower before modification, a gas-liquid contact part where the scrubbing liquid and the exhaust gas are brought into contact is formed in a scrubbing liquid reachable area where the scrubbing liquid injected upward from the liquid column nozzles in the form of liquid columns reaches in the interior space of the absorption 10 tower body. The upper end of the scrubbing liquid reachable area is the top of spout. According to the above method (1), the method for modifying a liquid column type absorption tower includes the spraying device addition step of adding a spraying device, and the scrubbing liquid supply line addition step of adding at least one scrubbing liquid supply line. The spraying device added in the spraying device addition step sprays the scrubbing liquid 15 delivered through the scrubbing liquid supply line downward from a position above the liquid column nozzle. Therefore, a new gas-liquid contact area is formed above the upper end of the scrubbing liquid reachable area in the interior space of the absorption tower body, where the scrubbing liquid sprayed from the spraying device comes into contact with the exhaust gas. In other words, in the liquid column type absorption tower modified by the method for modifying 20 a liquid column type absorption tower, the gas-liquid contact part where the scrubbing liquid and exhaust gas come into contact is enlarged upward compared to the existing liquid column type absorption tower. Thus, since the liquid column type absorption tower after modification has a larger gas-liquid contact part than the liquid column type absorption tower before modification, the desulfurization and dust removal performance can be improved compared to 25 the liquid column type absorption tower before modification.
[0010] In addition, with the above method (1), the addition of the spraying device and at least one scrubbing liquid supply line can be performed in a short period of time and with a 4
small amount of work, and there is no need to perform long-term, large-scale work on the absorption tower body. Thus, it is possible to prevent an increase in modification cost.
[0011] (2) In some embodiments, in the method for modifying a liquid column type absorption tower described in the above (1), the scrubbing liquid supply line addition step includes a supply pump addition step of adding a first supply pump for supplying the scrubbing 5 liquid to the spraying device.
[0012] According to the above method (2), in the supply pump addition step, the first supply pump for supplying the scrubbing liquid to the spraying device is added. Specifically, the first supply pump is a separate pump from the supply pump (second supply pump) for supplying the scrubbing liquid to the liquid column nozzle. When the first supply pump is a 10 separate pump from the second supply pump, taking into account the head of the scrubbing liquid supply line and the pressure loss of the scrubbing liquid in the scrubbing liquid supply line, the amount and pressure of the scrubbing liquid supplied to the spraying device can be made appropriate. In addition, since the existing pump can be used as it is as the second supply pump, it is possible to prevent an increase in modification cost. 15
[0013] (3) In some embodiments, in the method for modifying a liquid column type absorption tower described in the above (1) or (2), the scrubbing liquid supply line addition step includes a regulating valve addition step of adding a regulating valve configured to regulate an amount of the scrubbing liquid flowing in the scrubbing liquid supply line.
[0014] According to the above method (3), by increasing or decreasing the amount of 20 scrubbing liquid flowing in the scrubbing liquid supply line with the regulating valve added in the regulating valve addition step, the amount of scrubbing liquid sprayed from the spraying device can be increased or decreased. By setting the amount of scrubbing liquid sprayed from the spraying device to an appropriate level, it is possible to ensure the necessary desulfurization performance and dust removal performance, while suppressing an increase in pressure loss of 25 exhaust gas due to an excessive spraying amount of scrubbing liquid.
[0015] (4) In some embodiments, the method for modifying a liquid column type absorption tower described in the any one of above (1) to (3) further comprises a nozzle 5
diameter increase step of increasing a nozzle diameter of the liquid column nozzle.
[0016] If the scrubbing liquid injected upward from the liquid column nozzles is applied to the spraying device, scale and other precipitates may adhere to the spraying device, degrading the spraying performance of the spraying device. With the above method (4), by increasing the nozzle diameter of the liquid column nozzle 5 in the nozzle diameter increase step, the height of the liquid column can be reduced while maintaining the flow rate of scrubbing liquid injected from the liquid column nozzles. When the height of the liquid column is reduced, it is possible to prevent the scrubbing liquid injected upward from the liquid column nozzles from being applied to the spraying device, and it is possible to prevent a reduction in the spraying performance of the spraying device due to 10 adhesion of precipitates.
[0017] (5) In some embodiments, in the method for modifying a liquid column type absorption tower described in any one of the above (1) to (4), a second supply pump for supplying a scrubbing liquid to the liquid column nozzle includes a stator blade with a fixed blade angle. 15
[0018] According to the above method (5), as the number of operating second supply pumps including stator blades increases, the height of the liquid column increases. For example, when switching the second supply pump to be operated, the spare second supply pump is started, so the height of the liquid column becomes higher than in normal operation. The higher the height of the liquid column, the more likely it is that the scrubbing liquid injected 20 upward from the liquid column nozzles is applied to the spraying device. With the above method, since the height of the liquid column can be reduced in the nozzle diameter increase step, even if the second supply pump includes a stator blade, it is possible to prevent the scrubbing liquid injected upward from the liquid column nozzles from being applied to the spraying device. 25
[0019] (6) In some embodiments, in the method for modifying a liquid column type absorption tower described in any one of the above (1) to (5), the spraying device includes any one of a hollow cone nozzle configured to produce a ring-shaped spray pattern, a full cone 6
nozzle configured to spray over an entire surface of a circular area, a two-fluid nozzle configured to spray a scrubbing liquid mixed with a gas as fine droplets, or a second liquid column nozzle which is a liquid column nozzle configured to inject a scrubbing liquid in the form of liquid columns.
[0020] With the above method (6), since the spraying device includes any one of the hollow 5 cone nozzle, the full cone nozzle, the two-fluid nozzle, or the second liquid column nozzle, it is possible to effectively bring the scrubbing liquid sprayed from the spraying device into gas-liquid contact with the exhaust gas.
[0021] (7) A liquid column type absorption tower according to at least one embodiment of the present invention is configured to clean an exhaust gas discharged from a combustion device 10 using a scrubbing liquid and comprises: an absorption tower body configured to define an interior space including a gas-liquid contact part configured to bring the exhaust gas and the scrubbing liquid into gas-liquid contact, and a liquid reservoir configured to store a scrubbing liquid; a liquid column nozzle disposed in the interior space and configured to inject a scrubbing liquid upward in the form of liquid columns; a spraying device disposed in the interior space at 15 a position above the liquid column nozzle and configured to spray a scrubbing liquid downward; a first scrubbing liquid supply line configured to extract the scrubbing liquid stored in the liquid reservoir through a first scrubbing liquid extraction port and deliver the scrubbing liquid to the liquid column nozzle; and a second scrubbing liquid supply line configured to extract the scrubbing liquid stored in the liquid reservoir through a second scrubbing liquid extraction port 20 different from the first scrubbing liquid extraction port and deliver the scrubbing liquid to the spraying device.
[0022] With the above configuration (7), since the liquid column type absorption tower includes the liquid column nozzle disposed in the interior space of the absorption tower body and configured to inject the scrubbing liquid upward in the form of liquid columns, and the 25 spraying device disposed in the interior space at a position above the liquid column nozzle and configured to spray the scrubbing liquid downward, as compared with the case where it includes either one of the liquid column nozzle or the spraying device, the gas-liquid contact part where 7
the scrubbing liquid and the exhaust gas come into contact can be enlarged. Consequently, it is possible to improve the desulfurization performance and the dust removal performance of the liquid column type absorption tower.
[0023] Additionally, with the above configuration (7), the absorption tower includes the first scrubbing liquid supply line configured to extract the scrubbing liquid stored in the liquid 5 reservoir of the absorption tower body through the first scrubbing liquid extraction port and deliver the scrubbing liquid to the liquid column nozzle, and the second scrubbing liquid supply line configured to extract the scrubbing liquid stored in the liquid reservoir through the second scrubbing liquid extraction port and deliver the scrubbing liquid to the spraying device. In other words, the scrubbing liquid injected from the liquid column nozzles and the scrubbing 10 liquid sprayed from the spraying device are common in that the supply source is the liquid reservoir of the absorption tower body, but are delivered through scrubbing liquid supply lines (first scrubbing liquid supply line and second scrubbing liquid supply line) having different heads and pressure losses of the scrubbing liquid. Since the respective scrubbing liquid supply lines are different, the amount and pressure of the scrubbing liquid supplied to the liquid column 15 nozzle or the spraying device can be made appropriate.
[0024] (8) In some embodiments, in the method for modifying a liquid column type absorption tower described in the above (7), the liquid column type absorption tower further comprises a regulating valve disposed in the second scrubbing liquid supply line and configured to regulate an amount of the scrubbing liquid flowing in the second scrubbing liquid supply line. 20
[0025] According to the above configuration (8), by increasing or decreasing the amount of scrubbing liquid flowing in the second scrubbing liquid supply line with the regulating valve, the amount of scrubbing liquid sprayed from the spraying device can be increased or decreased. By setting the amount of scrubbing liquid sprayed from the spraying device to an appropriate level, it is possible to ensure the necessary desulfurization performance and dust removal 25 performance, while suppressing an increase in pressure loss of exhaust gas due to an excessive spraying amount of scrubbing liquid.
[0026] (9) In some embodiments, in the method for modifying a liquid column type 8
absorption tower described in above (7) or (8), the spraying device includes any one of a hollow cone nozzle configured to produce a ring-shaped spray pattern, a full cone nozzle configured to spray over an entire surface of a circular area, a two-fluid nozzle configured to spray a scrubbing liquid mixed with a gas as fine droplets, or a second liquid column nozzle which is a liquid column nozzle configured to inject a scrubbing liquid in the form of liquid columns. 5
[0027] With the above configuration (9), since the spraying device includes any one of the hollow cone nozzle, the full cone nozzle, the two-fluid nozzle, or the second liquid column nozzle, it is possible to effectively bring the scrubbing liquid sprayed from the spraying device into gas-liquid contact with the exhaust gas. 10
Advantageous Effects
[0028] At least one embodiment of the present invention provides a method for modifying a liquid column type absorption tower whereby it is possible to prevent an increase in modification cost and improve desulfurization and dust removal performance. 15
BRIEF DESCRIPTION OF DRAWINGS
[0029] FIG. 1 is a flowchart of a method for modifying a liquid column type absorption tower according to an embodiment. FIG. 2 is a schematic cross-sectional view of a liquid column type absorption tower before modification with the method for modifying a liquid column type absorption tower according 20 to an embodiment. FIG. 3 is a schematic cross-sectional view of a liquid column type absorption tower after modification with the method for modifying a liquid column type absorption tower according to an embodiment. FIG. 4 is a flowchart of a method for modifying a liquid column type absorption tower 25 according to another embodiment. FIG. 5 is a schematic configuration diagram for describing an example of a configuration of a scrubbing liquid circulation line.
9
FIG. 6 is a schematic cross-sectional view of a liquid column type absorption tower after modification with the method for modifying a liquid column type absorption tower according to another embodiment.
DETAILED DESCRIPTION 5
[0030] Embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It is intended, however, that unless particularly identified, dimensions, materials, shapes, relative positions, and the like of components described in the embodiments shall be interpreted as illustrative only and not intended to limit the scope of the present invention. 10 For instance, an expression of relative or absolute arrangement such as “in a direction”, “along a direction”, “parallel”, “orthogonal”, “centered”, “concentric” and “coaxial” shall not be construed as indicating only the arrangement in a strict literal sense, but also includes a state where the arrangement is relatively displaced by a tolerance, or by an angle or a distance whereby it is possible to achieve the same function. 15 For instance, an expression of an equal state such as “same” “equal” and “uniform” shall not be construed as indicating only the state in which the feature is strictly equal, but also includes a state in which there is a tolerance or a difference that can still achieve the same function. Further, for instance, an expression of a shape such as a rectangular shape or a cylindrical 20 shape shall not be construed as only the geometrically strict shape, but also includes a shape with unevenness or chamfered corners within the range in which the same effect can be achieved. On the other hand, an expression such as “comprise”, “include”, “have”, “contain” and “constitute” are not intended to be exclusive of other components. 25 The same features can be indicated by the same reference numerals and not described in detail.
[0031] FIG. 1 is a flowchart of a method for modifying a liquid column type absorption
10
tower according to an embodiment. FIG. 2 is a schematic cross-sectional view of a liquid column type absorption tower before modification with the method for modifying a liquid column type absorption tower according to an embodiment. FIG. 3 is a schematic cross-sectional view of a liquid column type absorption tower after modification with the method for modifying a liquid column type absorption tower according to an embodiment. 5
[0032] The method 1 (1A) for modifying a liquid column type absorption tower according to some embodiments includes a spraying device addition step 11 of adding a spraying device 4, and a scrubbing liquid supply line addition step 12 of adding at least one scrubbing liquid supply line 7, as shown in FIG. 1. In other words, in the method 1 for modifying a liquid column type absorption tower, a liquid column type absorption tower 2A (liquid column type 10 absorption tower 2) before modification as shown in FIG. 2 is modified to a liquid column type absorption tower 2B (liquid column type absorption tower 2) after modification as shown in FIG. 3 by adding the spraying device 4 and the scrubbing liquid supply line 7.
[0033] The liquid column type absorption tower 2 is a device for desulfurizing exhaust gas discharged from a combustion device (not shown). Examples of the combustion device 15 include an engine such as a diesel engine, a gas turbine engine, or a steam turbine engine, and a boiler.
[0034] As shown in FIG. 2, the liquid column type absorption tower 2A before modification (liquid column type absorption tower 2) includes an absorption tower body 21 having an interior space 22 into which exhaust gas discharged from the combustion device is introduced. 20 In the illustrated embodiment, as shown in FIG. 2, the liquid column type absorption tower 2 includes an exhaust gas introduction section 23 for introducing the exhaust gas into the interior space 22, and an exhaust gas discharge section 24 for discharging the exhaust gas from the interior space 22. Further, as shown in FIG. 2, the absorption tower body 21 defines the interior space 22 by an inner surface 251 of at least one side wall 25, a ceiling surface 211, and 25 a bottom surface 212.
[0035] The direction in which the absorption tower body 21 and the exhaust gas introduction section 23 are adjacent is defined as a first direction; the horizontal direction 11
perpendicular to the first direction is defined as a second direction, the side adjacent to the exhaust gas introduction section 23 in the first direction is defined as a first side; and the side adjacent to the exhaust gas discharge section 24 in the first direction is defined as a second side. As shown in FIG. 1, a first side wall 25A, which is one of side walls 25 of the absorption tower body 21 on the first side in the first direction, has an exhaust gas introduction port 252 5 communicating with the lower interior space 22B. Further, the ceiling surface 211 of the absorption tower body 21 has an exhaust gas discharge port 213 communicating with the upper interior space 22A.
[0036] The exhaust gas introduced from a combustion device (not shown) to the exhaust gas introduction section 23 passes through the exhaust gas introduction section 23 and then is 10 introduced into the interior space 22 (lower interior space 22B) through the exhaust gas introduction port 252. The exhaust gas introduced into the interior space 22 flows in the lower interior space 22B from the first side wall 25A on the first side to a second side wall 25B on the second side and then rises in the interior space 22. The exhaust gas having risen to the upper interior space 22A is discharged to the exhaust gas discharge section 24 disposed above the 15 absorption tower body 21 through the exhaust gas discharge port 213.
[0037] The liquid column type absorption tower 2A (liquid column type absorption tower 2) before modification includes at least one liquid column nozzle 3 disposed in the interior space 22, as shown in FIG. 2. As shown in FIG. 2, the liquid column nozzle 3 is configured to inject the scrubbing liquid upward (downstream in the exhaust gas flow direction) in the form 20 of liquid columns. In the illustrated embodiment, the liquid column nozzle 3 is disposed above the upper end of the exhaust gas introduction port 252 and below the ceiling surface 211. Examples of the scrubbing liquid include liquids including an alkaline agent and seawater. Examples of the alkaline agent include CaCO3, NaOH, Ca(OH)2, NaHCO3, and Na2CO3. 25
[0038] The scrubbing liquid injected from the liquid column nozzle 3 forms a liquid column 30 above the liquid column nozzle 3. After forming the liquid column 30, the scrubbing liquid disperses at the top of spout 301, then falls down, impinges on scrubbing liquid injected upward
12
from the liquid column nozzle 3, and thus is atomized into fine droplets. The scrubbing liquid atomized into fine drops effectively comes into gas-liquid contact with exhaust gas and effectively absorbs air pollutants such as SOx (sulfur oxides) contained in the exhaust gas. Also, the scrubbing liquid atomized into fine drops removes soot and dust contained in exhaust gas from the exhaust gas. 5
[0039] As shown in FIG. 2, in the interior space 22 of the absorption tower body 21, a gas-liquid contact part 5 where the exhaust gas introduced into the interior space 22 and the scrubbing liquid come into contact is formed. As shown in FIG. 2, the gas-liquid contact part 5 includes a first gas-liquid contact part 5A where the scrubbing liquid injected from the liquid column nozzle 3 of the absorption tower body 21 upward in the form of a liquid column comes 10 into contact with the exhaust gas introduced into the interior space 22.
[0040] The first gas-liquid contact part 5A is formed in a scrubbing liquid reachable area 51 where the scrubbing liquid injected upward from the liquid column nozzle 3 reaches. Hereinafter, the upper end of the first gas-liquid contact part 5A (scrubbing liquid reachable area 51) is the top of spout 301. 15
[0041] As shown in FIG. 2, the interior space 22 is divided by the first gas-liquid contact part 5A into the upper interior space 22A above the first gas-liquid contact part 5A and the lower interior space 22B below the first gas-liquid contact part 5A. Further, as shown in FIG. 2, the interior space 22 has a liquid reservoir 22C for storing the scrubbing liquid below the lower interior space 22B. In other words, as shown in FIG. 2, the interior space 22 includes, in order 20 from the top, the upper interior space 22A, the first gas-liquid contact part 5A, the lower interior space 22B, and the liquid reservoir 22C.
[0042] The liquid reservoir 22C is configured to store the scrubbing liquid. The scrubbing liquid stored in the liquid reservoir 22C may come into gas-liquid contact with the exhaust gas introduced to the interior space 22 and absorb air pollutants such as SOx (sulfur oxides) 25 contained in the exhaust gas. Specifically, the scrubbing liquid stored in the liquid reservoir 22C may contain reaction products produced from SOx absorbed from the exhaust gas and oxidation products produced by oxidation of the reaction products. Examples of the reaction
13
products include sulfites produced by the absorption of SO2 in the scrubbing liquid. Examples of the oxidation products include gypsum. In the illustrated embodiment, the liquid reservoir 22C is disposed below the gas-liquid contact part 5. Also, the liquid reservoir 22C is disposed such that the liquid surface is positioned below the lower end of the exhaust gas introduction port 252. 5
[0043] In the illustrated embodiment, as shown in FIG. 2, the side wall 25 (second side wall 25B) has openings as a scrubbing liquid discharge port 253 (first scrubbing liquid discharge port 254 and second scrubbing liquid discharge port 255) for discharging the scrubbing liquid stored in the liquid reservoir 22C to the outside. Each of the first scrubbing liquid discharge port 254 and the second scrubbing liquid discharge port 255 is located near the bottom surface 10 212 of the absorption tower body 21 in the vertical direction and communicates with the liquid reservoir 22C. The first scrubbing liquid discharge port 254 may be at the same height as the second scrubbing liquid discharge port 255. If the liquid column type absorption tower 2 has no second scrubbing liquid discharge port 255, the scrubbing liquid supply line addition step 12 may include a step of opening the second scrubbing liquid discharge port 255. 15
[0044] In the illustrated embodiment, as shown in FIG. 2, the liquid column type absorption tower 2 further includes a scrubbing liquid circulation line 6 (first scrubbing liquid supply line) configured to extract the scrubbing liquid stored in the liquid reservoir 22C through the first scrubbing liquid discharge port 254 (scrubbing liquid discharge port 253) and deliver the scrubbing liquid to the liquid column nozzle 3. In the embodiment shown in FIG. 2, the 20 scrubbing liquid circulation line 6 delivers the scrubbing liquid stored in the liquid reservoir 22C to the liquid column nozzle 3 via a liquid column pipe 31 with a plurality of liquid column nozzles 3. The liquid column type absorption tower 2 may include a scrubbing liquid introduction line (not shown) configured to introduce the scrubbing liquid from the outside of the absorption tower body 21 to the liquid reservoir 22C. 25
[0045] In the illustrated embodiment, as shown in FIG. 2, the liquid column pipe 31 extends along the first direction (at a height position above the upper end of the exhaust gas introduction port 252 in the lower interior space 22B) in the interior space 22 of the absorption tower body
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21. In other embodiments, the liquid column pipe 31 may extend along a direction intersecting the first direction in the interior space 22 of the absorption tower body 21. For example, the liquid column pipe 31 may extend along the second direction in the interior space 22 of the absorption tower body 21. 5
[0046] The scrubbing liquid circulation line 6 includes at least one pipe 61 connecting the first scrubbing liquid discharge port 254 and the liquid column pipe 31, and a scrubbing liquid circulation pump 62 disposed in the middle of the scrubbing liquid circulation line 6. The scrubbing liquid circulation pump 62 is a device for extracting the scrubbing liquid stored in the liquid reservoir 22C through the first scrubbing liquid discharge port 254 and 10 delivering it to the liquid column pipe 31. The scrubbing liquid circulation pump 62 has a rotating part 621 such as a rotating blade (e.g., a stator blade 621A with a fixed blade angle or a rotor blade). Part of the scrubbing liquid stored in the liquid reservoir 22C is pumped by the scrubbing liquid circulation pump 62, passes through the scrubbing liquid circulation line 6 and the liquid column pipe 31, and is fed to the liquid column nozzle 3. 15
[0047] In the illustrated embodiment, the scrubbing liquid circulation line 6 includes a valve 63 disposed in the scrubbing liquid circulation line 6 on the upstream side (first scrubbing liquid discharge port 254 side) of the scrubbing liquid circulation pump 62. The valve 63 has a movable mechanism to open and close the scrubbing liquid circulation line 6 which is a flow passage for the scrubbing liquid. The valve 63 may be an open/close valve or a flow-rate 20 regulating valve.
[0048] On the downstream side of the gas-liquid contact part 5A (first gas-liquid contact part 5A) in the exhaust gas flow direction, a mist eliminator 26 is disposed. The mist eliminator 26 is configured to remove moisture from the exhaust gas passing through the mist eliminator 26. The exhaust gas having passed through the mist eliminator 26 is discharged to 25 the outside of the liquid column type absorption tower 2.
[0049] In the illustrated embodiment, as shown in FIG. 2, the mist eliminator 26 is disposed in the upper interior space 22A. Specifically, the mist eliminator 26 is disposed at a position
15
above the upper end (top of spout 301) of the scrubbing liquid reachable area 51 in the interior space 22 and below the ceiling surface 211 of the absorption tower body 21. Further, the mist eliminator 26 extends along the horizontal direction so as to separate the upstream side and the downstream side in the exhaust gas flow direction.
[0050] In the illustrated embodiment, the mist eliminator 26 has a multi-stage structure. 5 Specifically, the mist eliminator 26 includes a mist eliminator 26A disposed in the upper interior space 22A and a mist eliminator 26B disposed in the upper interior space 22A and above the mist eliminator 26A. The exhaust gas introduced to the interior space 22 passes through the mist eliminators 26 (26A, 26B) and then is discharged from the liquid column type absorption tower 2. 10
[0051] As shown in FIG. 3, the liquid column type absorption tower 2B after modification include, in addition to the components included in the liquid column type absorption tower 2A before modification, a spraying device 4 added in the spraying device addition step 11 and a scrubbing liquid supply line 7 added in the scrubbing liquid supply line addition step 12.
[0052] As shown in FIG. 3, the spraying device 4 is disposed above the scrubbing liquid 15 reachable area 51 where the scrubbing liquid injected upward from the liquid column nozzle 3 reaches. Further, the spraying device 4 is configured to spray the scrubbing liquid downward in the vertical direction.
[0053] In the illustrated embodiment, the spraying device 4 includes a spray pipe 42 extending along the first direction in the upper interior space 22A of the absorption tower body 20 21 and a plurality of spray nozzles 41 disposed on the spray pipe 42. The spray nozzle 41 is configured to spray the scrubbing liquid to the upstream side in the flow direction of the exhaust gas. In other embodiments, the spray pipe 42 may extend along a direction intersecting the first direction in the upper interior space 22A of the absorption tower body 21. For example, 25 the spray pipe 42 may extend along the second direction in the upper interior space 22A of the absorption tower body 21.
[0054] The scrubbing liquid sprayed from the spraying device 4 comes into gas-liquid 16
contact with exhaust gas, absorbs air pollutants such as SOx (sulfur oxides) contained in the exhaust gas and remove soot and dust contained in the exhaust gas. As shown in FIG. 3, a gas-liquid contact area 52 (second gas-liquid contact part 5B) where the scrubbing liquid sprayed from the spraying device 4 comes into contact with the exhaust gas introduced to the interior space 22 is formed above the first gas-liquid contact part 5A (scrubbing liquid reachable 5 area 51). The upper end of the gas-liquid contact area 52 (second gas-liquid contact part 5B) is a discharge port 43 of the spray nozzle 41 for spraying the scrubbing liquid, and the lower end is the top of spout 301.
[0055] As shown in FIG. 3, the height of the liquid column 30 is defined as H1, and the height of the gas-liquid contact area 52 in the vertical direction is defined as H2. The gas-10 liquid contact part 5 of the liquid column type absorption tower 2A before modification, which includes only the first gas-liquid contact part 5A, has the height in the vertical direction of H1. In contrast, the gas-liquid contact part 5 of the liquid column type absorption tower 2B after modification, which includes the first gas-liquid contact part 5A and the second gas-liquid contact part 5B, has the height in the vertical direction of the sum of H1 and H2. In other 15 words, the length of the gas-liquid contact part 5 of the liquid column type absorption tower 2B after modification in the vertical direction is larger than that of the liquid column type absorption tower 2A before modification.
[0056] As shown in FIG. 3, the scrubbing liquid supply line 7 (second scrubbing liquid supply line) is configured to extract the scrubbing liquid stored in the liquid reservoir 22C 20 through the second scrubbing liquid discharge port 255 (scrubbing liquid discharge port 253) and deliver the scrubbing liquid to the spray nozzle 41 via the spray pipe 42. In the illustrated embodiment, as shown in FIG. 3, the scrubbing liquid supply line 7 includes at least one supply pipe 71 connecting the second scrubbing liquid discharge port 255 and the spray pipe 42, and a scrubbing liquid supply pump 72 (first supply pump) disposed in 25 the middle of the scrubbing liquid supply line 7. The scrubbing liquid supply pump 72 is a device for extracting the scrubbing liquid stored in the liquid reservoir 22C through the second scrubbing liquid discharge port 255 and delivering it to the spray pipe 42. Part of the 17
scrubbing liquid stored in the liquid reservoir 22C is pumped by the scrubbing liquid supply pump 72, passes through the scrubbing liquid supply line 7 and the spray pipe 42, and is fed to the spray nozzle 41.
[0057] In the illustrated embodiment, as shown in FIG. 3, the scrubbing liquid supply line 7 includes at least one valve 73 disposed in the scrubbing liquid supply line 7 on the upstream 5 side (second scrubbing liquid discharge port 255 side) of the scrubbing liquid supply pump 72, and at least one valve 74 disposed in the scrubbing liquid supply line 7 on the downstream side (spray pipe 42 side) of the scrubbing liquid supply pump 72. Each of the valve 73 and the valve 74 has a movable mechanism to open and close the scrubbing liquid supply line 7 which is a flow passage for the scrubbing liquid. Each of the valve 73 and the valve 74 may be an 10 open/close valve or a flow-rate regulating valve.
[0058] As described above, the method 1 (1A) for modifying a liquid column type absorption tower includes the spraying device addition step 11 of adding the spraying device 4, and the scrubbing liquid supply line addition step 12 of adding the scrubbing liquid supply line 7, as shown in FIG. 1. 15 In the illustrated embodiment, the scrubbing liquid supply line addition step 12 is performed after the spraying device addition step 11. Before laying the scrubbing liquid supply line 7, there is plenty of space outside the absorption tower body 21, so it is easy to introduce the spraying device 4 inside the absorption tower body 21. In other embodiments, the scrubbing liquid supply line addition step 12 is performed 20 before the spraying device addition step 11.
[0059] In the illustrated embodiment, as shown in FIG. 1, the spraying device addition step 11 includes a spray nozzle attachment step 111 of attaching the spray nozzle 41 to the spray pipe 42 and a spray pipe laying step 112 of laying the spray pipe 42 to the absorption tower body 21. 25
[0060] In the illustrated embodiment, as shown in FIG. 1, the scrubbing liquid supply line addition step 12 includes a supply pipe laying step 121 of laying the supply pipe 71, a supply pump addition step 122 of adding the scrubbing liquid supply pump 72, and a valve addition
18
step 123 of adding at least one of the valve 73 or the valve 74.
[0061] As described above, the method 1 for modifying a liquid column type absorption tower according to some embodiments includes the spraying device addition step 11 of adding the spraying device 4, and the scrubbing liquid supply line addition step 12 of adding the scrubbing liquid supply line 7, as shown in FIG. 1. Further, as described above, the liquid 5 column type absorption tower 2A before modification includes the absorption tower body 21 having the interior space 22, and the liquid column nozzle 3. In this case, in the liquid column type absorption tower 2A before modification, the first gas-liquid contact part 5A (gas-liquid contact part 5) where the scrubbing liquid and the exhaust gas are brought into contact is formed in the scrubbing liquid reachable area 51 where the scrubbing liquid injected upward from the 10 liquid column nozzle 3 in the form of a liquid column reaches in the interior space 22 of the absorption tower body 21. The upper end of the scrubbing liquid reachable area 51 (first gas-liquid contact part 5A) is the top of spout 301 of the liquid column 30.
[0062] According to the above method, the method 1 for modifying a liquid column type absorption tower includes the spraying device addition step 11 of adding the spraying device 4, 15 and the scrubbing liquid supply line addition step 12 of adding the scrubbing liquid supply line 7. The spraying device 4 added in the spraying device addition step 11 sprays the scrubbing liquid delivered through the scrubbing liquid supply line 7 downward from a position above the liquid column nozzle 3. Therefore, a gas-liquid contact area 52 (second gas-liquid contact part 5B) is additionally formed above the upper end (top of spout 301) of the scrubbing liquid 20 reachable area 51 in the interior space 22 of the absorption tower body 21, where the scrubbing liquid sprayed from the spraying device 4 comes into contact with the exhaust gas. In other words, in the liquid column type absorption tower 2B modified by the method 1 for modifying a liquid column type absorption tower, the gas-liquid contact part 5 where the scrubbing liquid and exhaust gas come into contact is enlarged upward compared to the (existing) liquid column 25 type absorption tower 2A before modification. Thus, since the liquid column type absorption tower 2B after modification has a larger gas-liquid contact part 5 than the liquid column type absorption tower 2A before modification, the desulfurization and dust removal performance can 19
be improved compared to the liquid column type absorption tower 2A before modification.
[0063] In addition, with the above method, the addition of the spraying device 4 and at least one scrubbing liquid supply line 7 can be performed in a short period of time and with a small amount of work, and there is no need to perform long-term, large-scale work on the absorption tower body 21. Thus, it is possible to prevent an increase in modification cost. 5
[0064] In some embodiments, as shown in FIG. 1, the scrubbing liquid supply line addition step 12 includes the supply pump addition step 122 of adding the scrubbing liquid supply pump 72 (first supply pump) for supplying the scrubbing liquid to the spraying device 4. In this case, in the supply pump addition step 122, the scrubbing liquid supply pump 72 for supplying the scrubbing liquid to the spraying device 4 is added. Specifically, the scrubbing liquid supply 10 pump 72 is a separate pump from the scrubbing liquid circulation pump 62 (second supply pump) for supplying the scrubbing liquid to the liquid column nozzle 3. When the scrubbing liquid supply pump 72 is a separate pump from the scrubbing liquid circulation pump 62, taking into account the head of the scrubbing liquid supply line 7 and the pressure loss of the scrubbing liquid in the scrubbing liquid supply line 7, the amount and pressure of the scrubbing liquid 15 supplied to the spraying device 4 can be made appropriate. In addition, since the existing pump can be used as it is for supplying the scrubbing liquid to the liquid column nozzle 3, it is possible to prevent an increase in modification cost.
[0065] In some embodiments, as shown in FIG. 1, the scrubbing liquid supply line addition step 12 includes the valve addition step 123. The valve (valves 73, 74) added in the valve 20 addition step 123 is composed of a regulating valve configured to regulate the amount of scrubbing liquid flowing in the scrubbing liquid supply line 7. In this case, by increasing or decreasing the amount of scrubbing liquid flowing in the scrubbing liquid supply line 7 with the regulating valve added in the valve addition step 123 (regulating valve addition step), the amount of scrubbing liquid sprayed from the spraying device 4 can be increased or decreased. 25 By setting the amount of scrubbing liquid sprayed from the spraying device 4 to an appropriate level, it is possible to ensure the necessary desulfurization performance and dust removal performance, while suppressing an increase in pressure loss of exhaust gas due to an excessive 20
spraying amount of scrubbing liquid.
[0066] FIG. 4 is a flowchart of the method for modifying a liquid column type absorption tower according to another embodiment. FIG. 5 is a schematic configuration diagram for describing an example of a configuration of the scrubbing liquid circulation line. If the scrubbing liquid injected upward from the liquid column nozzle 3 is applied to the 5 spraying device 4, scale and other precipitates may adhere to the spraying device 4, degrading the spraying performance of the spraying device 4. Hereinafter, an example of the case where the scrubbing liquid injected upward from the liquid column nozzle 3 may be applied to the spraying device 4 will be described with reference to FIG. 5.
[0067] As shown in FIG. 5, in the absorption tower body 21, a plurality of liquid column 10 pipes 31 (31A to 31D) are arranged in the second direction (horizontal direction). Further, a plurality of scrubbing liquid discharge ports 253 (253A to 254D) open at intervals in the horizontal direction in the second side wall 25B of the absorption tower body 21.
[0068] Further, the scrubbing liquid circulation line 6 includes a plurality of first conduits 64A to 64D, one second conduit 65, and a plurality of third conduits 66A to 66D. 15 The upstream end of each of the first conduits 64A to 64D is connected to a corresponding one of the scrubbing liquid discharge ports 253, and the downstream end joins the others at a joint portion 67. The first conduits 64A to 64D are equipped with scrubbing liquid circulation pumps 62A to 62D and valves 63A to 63D, respectively. The second conduit 65 is connected at the upstream end to the joint portion 67 and 20 connected at the downstream end to a branch portion 68. The upstream end of each of the third conduits 66A to 66D is connected to the branch portion 68 and branches from the branch portion 68, and the downstream end is connected to a corresponding one of the liquid column pipes 31 (31A to 31D).
[0069] When each of the scrubbing liquid circulation pumps 62 (62A to 62D) includes a 25 stator blade 621A with a fixed blade angle, the height of the liquid column 30 (length H1 of the first gas-liquid contact part 5A in the vertical direction) increases or decreases according to the increase or decrease in the number of operating scrubbing liquid circulation pumps 62. In 21
other words, as the number of operating scrubbing liquid circulation pumps 62 increases, the height of the liquid column 30 increases. For example, when switching the scrubbing liquid circulation pump 62 to be operated, the spare scrubbing liquid circulation pump 62 is started, so the height of the liquid column 30 becomes higher than in normal operation. The higher the height of the liquid column 30, the more likely it is that the scrubbing liquid injected upward 5 from the liquid column nozzle 3 is applied to the spraying device 4.
[0070] In some embodiments, as shown in FIG. 4, the method 1 (1B) for modifying a liquid column type absorption tower includes the spraying device addition step 11, the scrubbing liquid supply line addition step 12, and a nozzle diameter increase step 13 of increasing the nozzle diameter of the liquid column nozzle 3 (the diameter of a discharge port 32). 10 In the illustrated embodiment, the spraying device addition step 11 and the scrubbing liquid supply line addition step 12 are performed after the nozzle diameter increase step 13. In other embodiments, the spraying device addition step 11 and the scrubbing liquid supply line addition step 12 may be performed before the nozzle diameter increase step 13.
[0071] In the illustrated embodiment, as shown in FIG. 4, the nozzle diameter increase step 15 13 includes a nozzle replacement step 131 or a nozzle hole machining step 132. In the nozzle replacement step 131, the liquid column nozzle 3 attached to the liquid column pipe 31 is replaced with another liquid column nozzle 3 having a larger nozzle diameter. In the nozzle hole machining step 132, the nozzle diameter is enlarged by cutting or other processing of the liquid column nozzle 3. 20
[0072] By increasing the nozzle diameter of the liquid column nozzle 3 in the nozzle diameter increase step 13, the height H1 (see FIG. 3) of the liquid column 30 can be reduced. When the height H1 of the liquid column 30 is reduced, it is possible to reduce the possibility that the scrubbing liquid injected upward from the liquid column nozzle 3 is applied to the spraying device 4. 25
[0073] Even if it is difficult to install the spraying device 4 since the space between the first gas-liquid contact part 5A and the mist eliminator 26 in the vertical direction is narrow before the nozzle diameter increase step 13, the nozzle diameter increase step 13 can widen the space 22
between the first gas-liquid contact part 5A and the mist eliminator 26, which makes it possible to install the spraying device 4.
[0074] By performing the nozzle diameter increase step 13, the height H1 of the liquid column 30 is reduced, but the height H2 of the gas-liquid contact area 52 in the vertical direction (see FIG. 3) is increased, so that the entire height of the gas-liquid contact part 5 in the vertical 5 direction can be maintained.
[0075] With the above method, by increasing the nozzle diameter of the liquid column nozzle 3 in the nozzle diameter increase step 13, the height H1 of the liquid column 30 can be reduced while maintaining the flow rate of scrubbing liquid injected from the liquid column nozzle 3. When the height H1 of the liquid column 30 is reduced, it is possible to prevent the 10 scrubbing liquid injected upward from the liquid column nozzle 3 from being applied to the spraying device 4, and it is possible to prevent a reduction in the spraying performance of the spraying device 4 due to adhesion of precipitates. Although the first gas-liquid contact part 5A becomes smaller with the reduction in the height H1 of the liquid column 30, the second gas-liquid contact part 5B becomes larger as the first gas-liquid contact part 5A becomes smaller, 15 so that the desulfurization and dust removal performance of the liquid column type absorption tower 2 does not deteriorate as a whole.
[0076] In some embodiments, the scrubbing liquid circulation pump 62 (second supply pump) for supplying the scrubbing liquid to the liquid column nozzle 3 includes a stator blade 621A with a fixed blade angle. In this case, as the number of operating scrubbing liquid 20 circulation pumps 62 including stator blades 621A increases, the height H1 of the liquid column 30 increases. For example, when switching the scrubbing liquid circulation pump 62 to be operated, the spare scrubbing liquid circulation pump 62 is started, so the height H1 of the liquid column 30 becomes higher than in normal operation. The higher the height H1 of the liquid column 30, the more likely it is that the scrubbing liquid injected upward from the liquid column 25 nozzle 3 is applied to the spraying device 4. Since the height H1 of the liquid column 30 can be reduced in the nozzle diameter increase step 13, even if the scrubbing liquid circulation pump 62 includes a stator blade 621A, it is possible to prevent the scrubbing liquid injected upward 23
from the liquid column nozzle 3 from being applied to the spraying device 4.
[0077] In some embodiments, the spraying device 4 includes, as the spray nozzle 41, any one of a single-phase (one-fluid) nozzle such as a hollow cone nozzle configured to produce a ring-shaped spray pattern or a full cone nozzle configured to spray over the entire surface of a circular area, a two-phase (two-fluid) nozzle configured to spray the scrubbing liquid mixed 5 with a gas as fine droplets, or a second liquid column nozzle which is a liquid column nozzle configured to inject the scrubbing liquid in the form of liquid columns. With the above method, since the spraying device 4 includes any one of a single-phase (one-fluid) nozzle such as a hollow cone nozzle or a full cone nozzle, a two-phase (two-fluid) nozzle, or a second liquid column nozzle, the scrubbing liquid sprayed from the spraying device 4 effectively comes into 10 gas-liquid contact with the exhaust gas, so that it is possible to effectively absorb and remove air pollutants contained in the exhaust gas. Thus, with the above method, it is possible to improve the desulfurization performance and dust removal performance of the second gas-liquid contact part 5B.
[0078] FIG. 6 is a schematic cross-sectional view of a liquid column type absorption tower 15 after modification with the method for modifying a liquid column type absorption tower according to another embodiment. In the above-described liquid column type absorption tower 2 (2A, 2B), the exhaust gas discharge port 213 is formed in the ceiling surface 211 of the absorption tower body 21, and the exhaust gas discharge section 24 is disposed vertically above the absorption tower body 21. 20 In contrast, in the liquid column type absorption tower 2 (2C), as shown in FIG. 6, an exhaust gas discharge port 256 (corresponding to the exhaust gas discharge port 213 in FIG. 3) is formed in the side wall 25 (second side wall 25B) of the absorption tower body 21, and the exhaust gas discharge section 24 is disposed on the other side of the absorption tower body 21. Further, a mist eliminator 26 is disposed in the exhaust gas discharge section 24. The mist eliminator 26 25 (26C) extends along the vertical direction so as to separate the upstream side and the downstream side in the exhaust gas flow direction. In this case, the spraying device 4 is disposed between the ceiling surface 211 of the absorption tower body 21 and the top of spout 24
301 (the upper end of the first gas-liquid contact part 5A) in the vertical direction.
[0079] As shown in FIGs. 3 and 6, the liquid column type absorption tower 2 according to some embodiments includes: the absorption tower body 21 configured to define the interior space 22 including the gas-liquid contact part 5 configured to bring the exhaust gas and the scrubbing liquid into gas-liquid contact, and the liquid reservoir 22C configured to store the 5 scrubbing liquid; the liquid column nozzle 3; the spraying device 4; the scrubbing liquid circulation line 6 (first scrubbing liquid supply line) configured to extract the scrubbing liquid stored in the liquid reservoir 22C through the first scrubbing liquid discharge port 254 and deliver the scrubbing liquid to the liquid column nozzle 3; and the scrubbing liquid supply line 7 (second scrubbing liquid supply line) configured to extract the scrubbing liquid stored in the 10 liquid reservoir 22C through the second scrubbing liquid discharge port 255 different from the first scrubbing liquid discharge port 254 and deliver the scrubbing liquid to the spraying device 4.
[0080] With the above configuration, since the liquid column type absorption tower 2 includes the liquid column nozzle 3 disposed in the interior space 22 of the absorption tower 15 body 21 and configured to inject the scrubbing liquid upward in the form of liquid columns, and the spraying device 4 disposed in the interior space 22 at a position above the liquid column nozzle 3 and configured to spray the scrubbing liquid downward, as compared with the case where it includes either one of the liquid column nozzle 3 or the spraying device 4, the gas-liquid contact part 5 where the scrubbing liquid and the exhaust gas come into contact can be 20 enlarged. Consequently, it is possible to improve the desulfurization performance and the dust removal performance of the liquid column type absorption tower 2.
[0081] Additionally, with the above configuration, the absorption tower includes the scrubbing liquid circulation line 6 (first scrubbing liquid supply line) configured to extract the scrubbing liquid stored in the liquid reservoir 22C through the first scrubbing liquid discharge 25 port 254 (first scrubbing liquid extraction port) and deliver the scrubbing liquid to the liquid column nozzle 3, and the scrubbing liquid supply line 7 (second scrubbing liquid supply line) configured to extract the scrubbing liquid stored in the liquid reservoir 22C through the second 25
scrubbing liquid discharge port 255 (second scrubbing liquid extraction port) and deliver the scrubbing liquid to the spraying device 4. In other words, the scrubbing liquid injected from the liquid column nozzle 3 and the scrubbing liquid sprayed from the spraying device 4 are common in that the supply source is the liquid reservoir 22C of the absorption tower body 21, but are delivered through scrubbing liquid supply lines (scrubbing liquid circulation line 6 and 5 scrubbing liquid supply line 7) having different heads and pressure losses of the scrubbing liquid. Since the respective scrubbing liquid supply lines (scrubbing liquid circulation line 6 and scrubbing liquid supply line 7) are different, the amount and pressure of the scrubbing liquid supplied to the liquid column nozzle 3 or the spraying device 4 can be made appropriate.
[0082] The present invention is not limited to the embodiments described above, but 10 includes modifications to the embodiments described above, and embodiments composed of combinations of those embodiments.
[0083] For example, in the above-described embodiments, the exhaust gas discharge section 24 is disposed on the opposite side of the absorption tower body 21 from the exhaust gas introduction section 23 in the first direction, but it may be disposed on the same side as the 15 exhaust gas introduction section 23. Further, the exhaust gas discharge section 24 may adjoin the absorption tower body 21 in the second direction perpendicular to the first direction in a top view.
Reference Signs List 20
[0084]
1, 1A, 1B Method for modifying liquid column type absorption tower
11 Spraying device addition step
111 Spray nozzle attachment step
112 Spray pipe laying step 25
12 Scrubbing liquid supply line addition step
121 Supply pipe laying step
122 Supply pump addition step
26
123 Valve addition step
13 Nozzle diameter increase step
131 Nozzle replacement step
132 Nozzle hole machining step
2, 2A, 2B Liquid column type absorption tower 5
21 Absorption tower body
211 Ceiling surface
212 Bottom surface
213 Exhaust gas discharge port
22 Interior space 10
22A Upper interior space
22B Lower interior space
22C Liquid reservoir
23 Exhaust gas introduction section
24 Exhaust gas discharge section 15
25 Side wall
25A First side wall
25B Second side wall
251 Inner surface
252 Exhaust gas introduction port 20
253 Scrubbing liquid discharge port
254 First scrubbing liquid discharge port
255 Second scrubbing liquid discharge port
256 Exhaust gas discharge port
26, 26A to 26C Mist eliminator 25
3 Liquid column nozzle
30 Liquid column
301 Top of spout
27
31 Liquid column pipe
32 Discharge port
4 Spraying device
41 Spray nozzle
42 Spray pipe 5
43 Discharge port
5 Gas-liquid contact part
5A First gas-liquid contact part
5B Second gas-liquid contact part
51 Scrubbing liquid reachable area 10
52 Gas-liquid contact area
6 Scrubbing liquid circulation line
61 Pipe
62, 62A to 62D Scrubbing liquid circulation pump
621 Rotating part 15
621A Stator blade
63, 63A to 63D Valve
64A to 64D First conduit
65 Second conduit
66A to 66D Third conduit 20
67 Joint portion
68 Branch portion
7 Scrubbing liquid supply line
71 Supply pipe
72 Scrubbing liquid supply pump 25
73, 74 Valve
H1 Height of liquid column
H2 Height of gas-liquid contact area of second gas-liquid contact part
28
I/We Claim:
1. A method for modifying a liquid column type absorption tower, the liquid column type absorption tower including an absorption tower body having an interior space, and a liquid column nozzle disposed in the interior space and configured to inject 5 a scrubbing liquid upward in the form of liquid columns, the method comprising: a spraying device addition step of adding a spraying device to a position above the liquid column nozzle, the spraying device being configured to spray a scrubbing liquid downward; and 10 a scrubbing liquid supply line addition step of adding at least one scrubbing liquid supply line for supplying a scrubbing liquid to the spraying device.
2. The method for modifying a liquid column type absorption tower according to claim 1, wherein the scrubbing liquid supply line addition step includes a supply pump addition 15 step of adding a first supply pump for supplying the scrubbing liquid to the spraying device.
3. The method for modifying a liquid column type absorption tower according to claim 1 or 2, wherein the scrubbing liquid supply line addition step includes a regulating valve addition 20 step of adding a regulating valve configured to regulate an amount of the scrubbing liquid flowing in the scrubbing liquid supply line.
4. The method for modifying a liquid column type absorption tower according to any one of claims 1 to 3, further comprising a nozzle diameter increase step of increasing a nozzle diameter 25 of the liquid column nozzle.
5. The method for modifying a liquid column type absorption tower according to any one of
29
claims 1 to 4, wherein a second supply pump for supplying a scrubbing liquid to the liquid column nozzle includes a stator blade with a fixed blade angle.
6. The method for modifying a liquid column type absorption tower according to any one of 5 claims 1 to 5, wherein the spraying device includes any one of a hollow cone nozzle configured to produce a ring-shaped spray pattern, a full cone nozzle configured to spray over an entire surface of a circular area, a two-fluid nozzle configured to spray a scrubbing liquid mixed with a gas as fine droplets, or a second liquid column nozzle which is a liquid column nozzle 10 configured to inject a scrubbing liquid in the form of liquid columns.
7. A liquid column type absorption tower configured to clean an exhaust gas discharged from a combustion device using a scrubbing liquid, the liquid column type absorption tower comprising: 15 an absorption tower body configured to define an interior space including a gas-liquid contact part configured to bring the exhaust gas and the scrubbing liquid into gas-liquid contact, and a liquid reservoir configured to store a scrubbing liquid; a liquid column nozzle disposed in the interior space and configured to inject a scrubbing liquid upward in the form of liquid columns; 20 a spraying device disposed in the interior space at a position above the liquid column nozzle and configured to spray a scrubbing liquid downward; a first scrubbing liquid supply line configured to extract the scrubbing liquid stored in the liquid reservoir through a first scrubbing liquid extraction port and deliver the scrubbing liquid to the liquid column nozzle; and 25 a second scrubbing liquid supply line configured to extract the scrubbing liquid stored in the liquid reservoir through a second scrubbing liquid extraction port different from the first scrubbing liquid extraction port and deliver the scrubbing liquid to the spraying device.
30
8. The liquid column type absorption tower according to claim 7, further comprising a regulating valve disposed in the second scrubbing liquid supply line and configured to regulate an amount of the scrubbing liquid flowing in the second scrubbing liquid supply line. 5
9. The liquid column type absorption tower according to claim 7 or 8, wherein the spraying device includes any one of a hollow cone nozzle configured to produce a ring-shaped spray pattern, a full cone nozzle configured to spray over an entire surface of a circular area, a two-fluid nozzle configured to spray a scrubbing liquid mixed with a gas as fine droplets, or a second liquid column nozzle which is a liquid column nozzle 10 configured to inject a scrubbing liquid in the form of liquid columns.