[DESCRIPTION]
[Technical Field]
[0001]
The present invention relates to an absorption tower for a desulfurizer that removes sulfur oxide from a flue gas. 5
[Background Art]
[0002]
For example, flue gases discharged from a combustion engine such as a boiler contain air pollutants such as SOx (sulfur oxide). One method for reducing SOx contained in a flue gas is a wet desulfurization method to absorb and 10 remove SO2 (sulfurous acid gas) or the like by using a cleaning liquid (absorbing liquid) such as an alkaline aqueous solution or absorbent slurry.
[0003]
As a desulfurizer using the wet desulfurization method described above, a liquid column type absorption tower that cleans a flue gas by jetting a cleaning 15 liquid upward so as to spout the cleaning liquid upward is known (see Patent Literature 1, for example). In the liquid column type absorption tower, the cleaning liquid jetted upward from each liquid column nozzle forms a liquid column above the liquid column nozzle. After forming the liquid column, the cleaning liquid is dispersed at the top of the spout, then drops, collides with 20 another cleaning liquid spouted from the liquid column nozzle, and is thus micronized. The micronized cleaning liquid comes into gas-liquid contact with a flue gas and absorbs air pollutants contained in the flue gas. Further, soot and 2
dust contained in the flue gas can be removed out of the flue gas by the micronized cleaning liquid.
[Citation List]
[Patent Literature]
[0004] 5
[PTL 1] Japanese Patent Application Laid-Open No. H10-128053
[Summary of Invention]
[Technical Problem]
[0005]
In recent years, emission regulations for air pollutants such as sulfur oxide 10 or soot and dust tend to become more stringent. Use of high quality fuel such as low sulfur fuel having a low sulfur content or low soot fuel having a low amount of soot and dust generated by combustion reduces the amount of emitted air pollutants.
[0006] 15
However, since the use of expensive high quality fuel leads to increased running cost, there is a demand for use of inexpensive fuel such as high sulfur fuel having a high sulfur content or high soot fuel having a high amount of soot and dust generated by combustion, and improved desulfurization performance and dust removal performance are desired. 20
[0007]
Accordingly, an object of the present invention is to provide an absorption tower for a desulfurizer that can improve desulfurization performance and dust 3
removal performance.
[Solution to Problem]
[0008]
To achieve the object described above, the first aspect of the present invention is an absorption tower for a desulfurizer that absorbs and removes sulfur 5 oxide in a flue gas by using a cleaning liquid and includes an absorption tower body, a liquid column nozzle, and a spray nozzle. The absorption tower body has an internal space through which a flue gas flows from below to above. The liquid column nozzle is provided in the internal space and jets a cleaning liquid upward in a liquid column form. The spray nozzle is provided in the internal 10 space above the liquid column nozzle and jets a cleaning liquid downward in a conical form. The spray nozzle is a hollow cone nozzle having an annular spraying pattern and is arranged at a height position that is higher than the highest reachable height of a liquid column formed of the cleaning liquid jetted from the liquid column nozzle. Immediately after jetted, the cleaning liquid jetted from 15 the spray nozzle spreads in a liquid film form and then drops, and the liquid film is divided into liquid film-divided droplet groups as the cleaning liquid drops. The liquid column nozzle is arranged at a height position that is lower than an occurrence height of the liquid film-divided droplet groups of the cleaning liquid jetted from the spray nozzle. 20
[0009]
In the first aspect, the liquid column nozzle that jets a cleaning liquid upward in a liquid column form is provided in the internal space of the absorption
4
tower body, and the spray nozzle that jets a cleaning liquid downward in a conical form is provided at a position that is higher than the position in the internal space at which the liquid column nozzle is provided. Thus, compared to an absorption tower including only any one of the liquid column nozzle and the spray nozzle, the range where the cleaning liquid and the flue gas may come into gas-liquid 5 contact with each other (gas-liquid contact range) expands in the flue gas flow direction. Therefore, compared to the absorption tower provided with only one of the liquid column nozzle and the spray nozzle, the desulfurization performance and dust removal performance can be improved.
[0010] 10
Further, the spray nozzle is a hollow cone nozzle having an annular spraying pattern. Immediately after jetted, the cleaning liquid jetted from the spray nozzle spreads in a liquid film form and then drops, and the liquid film is divided into liquid film-divided droplet groups as the cleaning liquid drops. The spray nozzle is arranged at a height position that is higher than the highest 15 reachable height of a liquid column formed of the cleaning liquid jetted from the liquid column nozzle, and the liquid column nozzle is arranged at a height position that is lower than an occurrence height of the liquid film-divided droplet groups of the cleaning liquid jetted from the spray nozzle. It is thus possible to suppress interference between droplets from the liquid column nozzle and droplets 20 from the spray nozzle and further improve the desulfurization performance and the dust removal performance.
[0011]
5
The second aspect of the present invention is the absorption tower of the first aspect, and the liquid column nozzle is arranged at a height position at which a liquid column formed of a cleaning liquid jetted from the liquid column nozzle does not interfere with the liquid film of a cleaning liquid jetted from the spray nozzle. 5
[0012]
In the second aspect, since the liquid column formed of the cleaning liquid jetted from the liquid column nozzle and the liquid film of the cleaning liquid jetted from the spray nozzle do not interfere with each other, it is possible to prevent a reduction in desulfurization performance due to unevenness of the 10 cleaning liquid that would otherwise be caused by interference between a liquid column and a liquid film.
[0013]
The third aspect of the present invention is the absorption tower of the first aspect, and the occurrence height of the liquid film-divided droplet groups of the 15 cleaning liquid jetted from the spray nozzle is higher than the highest reachable height of the liquid column formed of the cleaning liquid jetted from the liquid column nozzle.
[0014]
In the third aspect, since the occurrence height of the liquid film-divided 20 droplet groups of the cleaning liquid jetted from the spray nozzle is higher than the highest reachable height of the liquid column formed of the cleaning liquid jetted from the liquid column nozzle, it is possible to further suppress interference 6
between droplets from the liquid column nozzle and droplets from the spray nozzle.
[0015]
The fourth aspect of the present invention is the absorption tower of any one of the first to third aspects and includes a spray header extending substantially 5 horizontally so as to transverse the internal space and configured to support the spray nozzle and supply a cleaning liquid to the spray nozzle. The absorption tower body has a circumferential wall shaped in a tube erecting substantially vertically. The inner circumferential surface of the circumferential wall defines the internal space. A flue gas introduction port into which a flue gas flows is 10 provided to the circumferential wall. A passage blocking member protruding from the inner circumferential surface into the internal space is provided in at least a part of a height range that is higher than or equal to an upper end edge of the flue gas introduction port and lower than or equal to the spray header in the inner circumferential surface of the circumferential wall. 15
[0016]
In the fourth aspect, since the passage blocking member is provided to the circumferential edge portion in the internal space where straight passage of the flue gas is likely to occur, it is possible to reduce the flue gas discharged from the absorption tower without coming into gas-liquid contact with the cleaning liquid 20 and further improve the desulfurization performance and the dust removal performance.
[Advantageous Effects of Invention]
7
[0017]
According to the present invention, the desulfurization performance and the dust removal performance can be improved.
[Brief Description of Drawings]
[0018] 5
[Fig. 1]
Fig. 1 is a sectional view illustrating a general configuration of an absorption tower according to a first embodiment of the present invention.
[Fig. 2]
Fig. 2 is a conceptual diagram of a droplet distribution in a liquid column 10 and a droplet distribution in a spray.
[Fig. 3]
Fig. 3 is a schematic diagram schematically illustrating a dispersion of droplet groups jetted from a liquid column nozzle and a dispersion of droplet groups jetted from a spray nozzle. 15
[Fig. 4A]
Fig. 4A is a schematic diagram schematically illustrating interference between droplet groups jetted from the liquid column nozzle and droplet groups jetted from the spray nozzle, illustrating a state where there is interference.
[Fig. 4B] 20
Fig. 4B is a schematic diagram schematically illustrating interference between droplet groups jetted from the liquid column nozzle and droplet groups jetted from the spray nozzle, illustrating a state where there is no interference.
8
[Fig. 5]
Fig. 5 is a sectional view illustrating a general configuration of an absorption tower according to a second embodiment of the present invention.
[Fig. 6A]
Fig. 6A represents a sectional view each taken along arrow VI-VI of Fig. 5 5 that illustrate a plurality of examples of forms of a passage blocking member.
[Fig. 6B]
Fig. 6B represents a sectional view each taken along arrow VI-VI of Fig. 5 that illustrate a plurality of examples of forms of a passage blocking member.
[Fig. 6C] 10
Fig. 6C represents a sectional view each taken along arrow VI-VI of Fig. 5 that illustrate a plurality of examples of forms of a passage blocking member.
[Fig. 6D]
Fig. 6D represents a sectional view each taken along arrow VI-VI of Fig. 5 that illustrate a plurality of examples of forms of a passage blocking member. 15
[Description of Embodiments]
[0019]
First Embodiment
An absorption tower 1 for a desulfurizer according to a first embodiment of the present invention will be described with reference to Fig. 1 to Fig. 4. The 20 desulfurizer is a wet lime-plaster flue gas desulfurizer that uses a cleaning liquid (absorbing liquid) to absorb and remove sulfur oxide from a flue gas containing sulfur oxide generated by a combustion device (not illustrated) and includes the
9
absorption tower 1 to which the flue gas containing sulfur oxide is introduced. The combustion device encompasses engines such as a diesel engine, a gas turbine engine, a steam turbine engine, or the like in addition to a boiler of a thermal power plant or the like. Note that the white arrows F in Fig. 1 indicate the flue gas flow direction. 5
[0020]
Configuration of Absorption Tower
As illustrated in Fig. 1, the absorption tower 1 includes an absorption tower body 2 having an internal space 3 to which a flue gas from a combustion device is introduced. The absorption tower body 2 has a circumferential wall 6 10 shaped in a tube erecting substantially perpendicularly between the bottom surface 4 and the ceiling surface 5, and the vertically extending internal space 3 is defined by the bottom surface 4, the ceiling surface 5, and the inner circumferential surface 7 of the circumferential wall 6. The circumferential wall 6 may be cylindrical or may be rectangularly tubular. 15
[0021]
A flue gas introduction port 8 is provided on one side (front side) of the circumferential wall 6, and an inlet duct (flue gas introduction part) 9 is connected to the flue gas introduction port 8. A flue gas discharge port 10 is provided to the top of the other side (rear side) of the circumferential wall 6 facing away from 20 the flue gas introduction port 8, and an outlet duct (flue gas discharge part) 11 is connected to the flue gas discharge port 10. In the flue gas discharge port 10, the top surface of the outlet duct 11 is continuous from the ceiling surface 5 of the 10
absorption tower body 2. The inlet duct 9 and the outlet duct 11 may be cylindrical or may be rectangularly tubular. The flue gas discharged from the combustion device is introduced from the flue gas introduction port 8 to the internal space 3 via the inlet duct 9. The introduced flue gas flows from below to above in the internal space 3 and is discharged from the flue gas discharge port 5 10 via the outlet duct 11.
[0022]
In the internal space 3 of the absorption tower body 2, a liquid column header (liquid column tube) 21 including at least one (in the present embodiment, a plurality of) liquid column nozzle(s) 20 and a spray header (spray tube) 31 10 including at least one (in the present embodiment, a plurality of) spray nozzle(s) 30 are installed. The liquid column nozzles 20 are arranged above the upper end edge of the flue gas introduction port 8, and the spray nozzles 30 are arranged above the liquid column nozzle 20. That is, the height H1 of the liquid column nozzle 20 (the height of a jet orifice) is higher than the height H3 of the upper end 15 edge of the flue gas introduction port 8, and the height H2 of the spray nozzle 30 (the height of a jet orifice) is higher than the height H1 of the liquid column nozzle 20 (H3 < H1 < H2). Each height is a ground clearance from the ground on which the absorption tower body 2 is installed, for example.
[0023] 20
Each liquid column nozzle 20 is configured to jet a cleaning liquid upward (in the same direction as the flue gas flow direction) in a liquid column form. The liquid column header 21 extends substantially horizontally so as to transverse 11
the internal space 3. The liquid column header 21 supports the liquid column nozzles 20 and supplies a cleaning liquid to the liquid column nozzles 20. Although the arrangement pattern of the plurality of liquid column nozzles 20 is not particularly limited, it is preferable to arrange the liquid column nozzles 20 evenly on the nozzle arrangement plane in the internal space 3. 5
[0024]
Each spray nozzle 30 is configured to jet a cleaning liquid downward (the opposite direction to the flue gas flow direction) in a conical form. The spray header 31 extends substantially horizontally so as to transverse the internal space 3. The spray header 31 supports the spray nozzles 30 and supplies a cleaning 10 liquid to the spray nozzle 30. Although the arrangement pattern of the plurality of spray nozzles 30 is not particularly limited, it is preferable to arrange the spray nozzles 30 evenly on the nozzle arrangement plane in the internal space 3.
[0025]
The spray nozzle 30 of the present embodiment is a hollow cone nozzle 15 having an annular spraying pattern (the jet shape is hollow conical). Note that the spray nozzle 30 is not limited to a hollow cone nozzle and may be any nozzle that jets a cleaning liquid in a conical form. For example, the spray nozzle 30 may be another single-phase (single fluid) nozzle such as a full-cone nozzle for circular front jet or may be a two-phase (binary fluid) nozzle that mixes a gas with 20 a cleaning liquid into particulate droplets and sprays the particulate droplets.
[0026]
As the cleaning liquid, a liquid including an alkaline agent, seawater, or 12
the like may be used, for example. As the alkaline agent, CaCO3, NaOH, Ca(OH)2, NaHCO3, Na2CO3, or the like may be used, for example.
[0027]
The cleaning liquid jetted from the liquid column nozzles 20 forms liquid columns 26 above the liquid column nozzles 20. The cleaning liquid forming the 5 liquid column 26 is dispersed at the liquid column reachable point (the top of spout) 27 at which the upward penetrating force and the gravity are balanced and which is the highest reachable position, then drops, collides with a subsequent cleaning liquid spouted from the liquid column nozzle 20, and is micronized. Each droplet group (a number of droplets) of a cleaning liquid that has been 10 divided from the liquid column 26 at the liquid column reachable point 27, has dropped, and has been micronized is referred to as a liquid column-divided droplet group 28. The liquid column-divided droplet group 28 comes into gas-liquid contact with the flue gas and absorbs air pollutants such as SOx (sulfur oxide) contained in the flue gas. Further, the liquid column-divided droplet 15 group 28 removes soot and dust contained in the flue gas out of the flue gas.
[0028]
The spray nozzles 30 are arranged above the highest reachable height (the liquid column reachable point 27) of the liquid column 26 formed of the cleaning liquid jetted from the liquid column nozzle 20. That is, the height H4 of the 20 liquid column reachable point 27 is higher than the height H1 of the liquid column nozzle 20, and the height H2 of the spray nozzle 30 is higher than the height H4 of the liquid column reachable point 27 (H1 < H4 < H2).
13
[0029]
The cleaning liquid immediately after jetted from the spray nozzle 30 spreads in a liquid film form (a liquid film 36 spreads in a hollow conical shape), and the liquid film 36 is divided into droplets as it drops. Each droplet group (a plurality of droplets) of a cleaning liquid that has been divided and micronized 5 from the liquid film 36 is referred to as a liquid film-divided droplet group (or a spray-divided droplet group) 37. The liquid film-divided droplet group 37 comes into gas-liquid contact with the flue gas and absorbs air pollutants such as SOx (sulfur oxide) contained in the flue gas. Further, the liquid film-divided droplet group 37 removes soot and dust contained in the flue gas out of the flue 10 gas.
[0030]
The internal space 3 of the absorption tower body 2 is divided into a lower subspace 14 communicating with the inlet duct 9 via the flue gas introduction port 8, an upper subspace 15 communicating with the outlet duct 11 via the flue gas 15 discharge port 10, a gas-liquid contact region 16 between the lower subspace 14 and the upper subspace 15, and a liquid reservoir part 13 under the lower subspace 14. The gas-liquid contact region 16 is a region having the under limit at the jet orifice of the liquid column nozzle 20 and the upper limit at the jet orifice of the spray nozzle 30 (a region higher than or equal to the jet orifice of the liquid 20 column nozzle 20 and lower than or equal to the jet orifice of the spray nozzle 30), and the gas-liquid contact between the cleaning liquid and the flue gas mainly takes place in the gas-liquid contact region 16.
14
[0031]
The gas-liquid contact region 16 is divided into a first gas-liquid contact region 16A that is lower than or equal to the height of the liquid column reachable point 27 of the liquid column 26 formed by the liquid column nozzle 20 and a second gas-liquid contact region 16B that is higher than the height position of the 5 liquid column reachable point 27. That is, in the internal space 3, the upper subspace 15, the second gas-liquid contact region 16B, the first gas-liquid contact region 16A, the lower subspace 14, and the liquid reservoir part 13 are arranged in this order from above. The gas-liquid contact between the cleaning liquid jetted from the liquid column nozzle 20 and the flue gas mainly takes place in the first 10 gas-liquid contact region 16A, and the gas-liquid contact between the cleaning liquid jetted from the spray nozzle 30 and the flue gas mainly takes place in the second gas-liquid contact region 16B.
[0032]
Fine droplets accompanying the flue gas flow are removed by a mist 15 eliminator 12 installed at the top of the absorption tower 1 (the outlet duct 11 in the present embodiment). The temperature of a gas in which fine droplets have been removed by the mist eliminator 12 (treated gas) is elevated by a reheating unit (not illustrated) installed on downstream of the absorption tower 1 as required, and the treated gas is emitted from a stack (not illustrated). Note that 20 the mist eliminator 12 may be installed in the upper subspace 15 of the absorption tower body 2.
[0033]
15
The part under the internal space 3 of the absorption tower body 2 (the space under the lower subspace 14) forms the liquid reservoir part (absorption tower tank) 13 that stores the cleaning liquid. The cleaning liquid is jetted from the liquid column nozzles 20 and the spray nozzles 30, comes into gas-liquid contact with the flue gas and absorbs sulfur oxide, then drops in the internal space 5 3, and is stored in the liquid reservoir part 13. The liquid surface of the cleaning liquid stored in the liquid reservoir part 13 (overflow surface) is set at a position that is lower than the lower end edge of the flue gas introduction port 8. The cleaning liquid stored in the liquid reservoir part 13 may include a reaction product produced from SOx absorbed from the flue gas or an oxidized product 10 produced from oxidation of the reaction product. The reaction product is sulfite produced when SO2 is absorbed in the cleaning liquid, for example, and the oxidized product is plaster, for example. When the oxidized product is produced, an air supply device (not illustrated) that supplies air to the retained cleaning liquid may be provided in the liquid reservoir part 13. 15
[0034]
The absorption tower 1 includes a first cleaning liquid circulation line 22 and a second cleaning liquid circulation line 32. The first cleaning liquid circulation line 22 is configured to be able to draw the cleaning liquid stored in the liquid reservoir part 13 and deliver the drawn cleaning liquid to the liquid 20 column nozzles 20 via the liquid column header 21. The second cleaning liquid circulation line 32 is configured to be able to draw the cleaning liquid stored in the liquid reservoir part 13 and deliver the drawn cleaning liquid to the spray
16
nozzles 30 via the spray header 31. Note that the absorption tower 1 may include a cleaning liquid introduction line (not illustrated) used for introducing the cleaning liquid from outside of the absorption tower body 2 to the liquid reservoir part 13.
[0035] 5
The first cleaning liquid circulation line 22 includes at least one first circulation pipe 23 connected between the liquid reservoir part 13 and the liquid column header 21, a first circulation pump 24 provided on the way of the first circulation pipe 23, and a valve 25 that can open and close the first circulation pipe 23 upstream of the first circulation pump 24. The first circulation pump 24 10 draws the cleaning liquid stored in the liquid reservoir part 13 and delivers the drawn cleaning liquid to the liquid column nozzles 20 via the first circulation pipe 23 and the liquid column header 21. The valve 25 may be an on-off valve or may be a flow regulating valve. Further, instead of or in addition to the valve 25, a valve that can open and close the first circulation pipe 23 may be provided 15 downstream of the first circulation pump 24.
[0036]
The second cleaning liquid circulation line 32 includes at least one second circulation pipe 33 connected between the liquid reservoir part 13 and the spray header 31, a second circulation pump 34 provided on the way of the second 20 circulation pipe 33, and a valve 35 that can open and close the second circulation pipe 33 upstream of the second circulation pump 34. The second circulation pump 34 draws the cleaning liquid stored in the liquid reservoir part 13 and 17
delivers the drawn cleaning liquid to the spray nozzles 30 via the second circulation pipe 33 and the spray header 31. The valve 35 may be an on-off valve or may be a flow regulating valve. Further, instead of or in addition to the valve 35, a valve that can open and close the second circulation pipe 33 may be provided downstream of the second circulation pump 34. 5
[0037]
In the internal space 3 of the absorption tower 1, the first gas-liquid contact region 16A formed by the liquid column nozzles 20 and the second gas-liquid contact region 16B formed by the spray nozzles 30 are arranged in the flue gas flow direction, and the gas-liquid contact region 16 is formed of the first gas-10 liquid contact region 16A and the second gas-liquid contact region 16B. The droplet group from the liquid column nozzles 20 of the first gas-liquid contact region 16A and the droplet group from the spray nozzles 30 of the second gas-liquid contact region 16B differ in the distribution of particle diameters or the dispersion of droplets as described below, and when the flue gas passes through 15 both the first gas-liquid contact region 16A and the second gas-liquid contact region 16B, the gas-liquid contact rate increases.
[0038]
Expansion of Distribution of Particle Diameter of Droplet Group
The relationship between a particle diameter distribution (droplet 20 distribution in a liquid column) D1 of droplet groups jetted and divided from the liquid column nozzle 20 and a particle diameter distribution (droplet distribution in a spray) D2 of droplet groups jetted from the spray nozzle 30 will be described 18
with reference to Fig. 2. In Fig. 2, the droplet distribution D1 in a liquid column is represented by a solid line, and the droplet distribution D2 in a spray is represented by a dashed line.
[0039]
Fig. 2 is a conceptual diagram of a droplet distribution (particle diameter 5 distribution) in a liquid column and a droplet distribution (particle diameter distribution) in a spray. As illustrated in Fig. 2, the droplet groups generated by the cleaning liquid being jetted and divided from the spray nozzle 30 (the spray-divided droplet group 37 in Fig. 1) have the relatively small particle diameter distribution D2, and the droplet groups generated by the cleaning liquid being 10 jetted and divided from the liquid column nozzle 20 (the liquid column-divided droplet group 28 in Fig. 1) have the relatively large particle diameter distribution D1. It is therefore possible to generate droplet groups having a wide particle diameter distribution in the internal space 3 of the absorption tower body 2 through which the flue gas flows. 15
[0040]
Dispersion of Droplet Group
As illustrated in Fig. 3, droplets (the spray-divided droplet group 37) are likely to occur on the extension line of the liquid film 36 in the case of the spray nozzle 30, and droplets (the liquid column-divided droplet group 28) are likely to 20 occur perpendicularly downward of the liquid column reachable point 27 in the case of the liquid column nozzle 20. In Fig. 3, dispersion directions of the liquid column-divided droplet groups 28 are represented by arrows 40, and dispersion
19
directions of the spray-divided droplet groups 37 are represented by arrows 41. As discussed above, since the dispersion direction of the liquid column-divided droplet groups 28 and the dispersion direction of the spray-divided droplet groups 37 differ from each other, it is possible to disperse the droplet groups 28 and 37 of the cleaning liquid more evenly on the horizontal cross section of the internal 5 space 3 (the gas-liquid contact region 16) of the absorption tower body 2.
[0041]
Interference of Droplet Groups
Fig. 4 is a schematic diagram schematically illustrating interference between the liquid column-divided droplet group 28 and the liquid film-divided 10 droplet group 37. Fig. 4A illustrates a state where the liquid column reachable point 27 reaches the liquid film 36 and interferes therewith, and Fig. 4B illustrates a state where the liquid column reachable point 27 does not reach the liquid film 36 and does not interfere therewith. In the absorption tower 1 of the present embodiment in which the liquid column nozzles 20 and the spray nozzles 30 are 15 combined, there is a concern of interference between droplet groups. It is considered that the major concerns due to interference are the following three points.
[0042]
The first concern is integration of droplets. Integration of the liquid 20 column-divided droplet group 28 and the spray-divided droplet group 37 causes each droplet to increase in size and thus reduces the surface area of the droplet groups, which is disadvantageous for a flue gas desulfurizer using gas-liquid 20
contact.
[0043]
The second concern is collision between droplets. Collision between droplets includes collision between the liquid column-divided droplet group 28 and the liquid film-divided droplet group 37, collision between the liquid column-5 divided droplet group 28 and the liquid film 36, and collision between the liquid column 26 (the liquid column reachable point 27) and the liquid film 36. For example, it is considered that collision with the liquid film 36 may secondarily atomize the liquid column-divided droplet group 28 to be micronized, and such micronized droplet groups are advantageous for gas-liquid contact. However, 10 droplet groups micronized by secondary atomization are not always dispersed evenly in the internal space 3, and unevenly micronized droplet groups will be rather disadvantageous for gas-liquid contact and may reduce the desulfurization performance.
[0044] 15
The third concern is an increased pressure loss. A portion where interference occurs has a locally high density of droplet groups, and an increased pressure loss will require increased motive power.
[0045]
In the present embodiment, to prevent occurrence of such interference 20 described above, the height of the spray nozzle 30 relative to the liquid column nozzle 20 is set such that the occurrence height H5 of the liquid film-divided droplet group 37 generated from the liquid film 36 formed by the spray nozzle 30 21
is higher than the height H4 of the liquid column reachable point 27 that is the highest reachable height of the liquid column 26 formed by the liquid column nozzle 20 (H4 < H5).
[0046]
Suppression of Drift of Flue Gas 5
In the liquid column type absorption tower that jets a cleaning liquid by using only the liquid column nozzles 20, a phenomenon is observed that the desulfurization performance is higher in a case of a type where a mist eliminator is horizontally placed inside a vertical duct (outlet duct) extending upward from the internal space of the absorption tower body and the desulfurization 10 performance is lower in a case of a type where a mist eliminator is vertically placed inside a horizontal duct (outlet duct) extending horizontally from the top of the internal space of the absorption tower body. It is considered that such a phenomenon occurs because, in the latter type where the outlet duct extends horizontally, the flue gas is more likely to flow obliquely from the internal space 15 toward the outlet duct (drift is more likely to occur). In contrast, in the present embodiment, since the cleaning liquid is jetted from the spray nozzles 30 downstream (upper side) of the internal space 3, drift of the flue gas toward the outlet duct 11 can be suppressed by the cleaning liquid jetted from the spray nozzles 30. Thus, in addition to the improved desulfurization performance, an 20 increased flatting gas flow rate (a reduced sectional area of the tower) or increased dust removal performance can be expected.
[0047]
22
As described above, according to the present embodiment, compared to the liquid column type absorption tower or the spray type absorption tower, it is possible to expand the gas-liquid contact region 16 in the flue gas flow direction, generate droplet groups having a wide particle diameter distribution in the internal space 3 of the absorption tower body 2 through which the flue gas flows, and 5 suppress and disperse unevenness of droplet groups in the horizontal cross section of the internal space 3. Thus, the desulfurization performance and the dust removal performance can be improved.
[0048]
Further, the height of the spray nozzle 30 relative to the liquid column 10 nozzle 20 is set such that the occurrence height H5 of the liquid film-divided droplet group 37 generated from the liquid film 36 formed by the spray nozzle 30 is higher than the height H4 of the liquid column reachable point 27 that is the highest reachable height of the liquid column 26 formed by the liquid column nozzle 20. Thus, interference between droplets from the liquid column nozzles 15 20 and droplets from the spray nozzles 30 can be suppressed, and the desulfurization performance and the dust removal performance can be further improved.
[0049]
Further, it is possible to improve desulfurization performance and dust 20 removal performance by performing reconstruction work to add the spray nozzles 30 and components for jetting the cleaning liquid from the spray nozzles 30 (the spray header 31, the second cleaning liquid circulation line 32, or the like) on the 23
liquid column type absorption tower or by performing reconstruction work to add the liquid column nozzles 20 and components for jetting the cleaning liquid from the liquid column nozzles 20 (the liquid column header 21, the first cleaning liquid circulation line 22, or the like) on the spray type absorption tower.
[0050] 5
Second Embodiment
Next, the second embodiment of the present invention will be described with reference to Fig. 5 and Fig. 6. Since an absorption tower 50 of the present embodiment is an absorption tower in which a passage blocking member 51 is provided to the absorption tower body 2 of the first embodiment, the same 10 component as that in the first embodiment is labeled with the same reference, and the description thereof will be omitted. Further, depiction is omitted for some components not directly relevant to the present embodiment among components included in the absorption tower 1 of the first embodiment.
[0051] 15
In the desulfurizer, since desulfurization of a flue gas is performed through gas-liquid contact with a cleaning liquid, it is required to suppress, as much as possible, the flue gas from passing straight upward in the internal space 3 of the absorption tower 1 without coming into contact with the absorbing liquid. A part near the wall of the absorption tower body 2 (close to the inner circumferential 20 surface 7) or corners (for example, four corners when the circumferential wall 6 is rectangularly tubular) thereof are portions where straight passage of the flue gas is likely to occur. In the present embodiment, to suppress straight passage of the 24
flue gas, the passage blocking member 51 protruding from the inner circumferential surface 7 into the internal space 3 is provided to the circumferential edge portion of the internal space 3 where straight passage of the flue gas is likely to occur (see Fig. 5).
[0052] 5
The height position at which the passage blocking member 51 is attached is at least a part of a height range 53 that is higher than or equal to the upper end edge of the flue gas introduction port 8 and lower than or equal to the spray header 31. For example, when the height range 53 is divided into a first region that is a height range higher than or equal to the upper end edge of the flue gas 10 introduction port 8 and lower than or equal to the liquid column header 21 and a second region that is a height range higher than or equal to the liquid column header 21 and lower than or equal to the spray header 31, the passage blocking member 51 may be provided to only any one of these regions or may be provided to both of these regions. Further, a plurality of passage blocking members may 15 be provided in a single region.
[0053]
Examples of the shape of the passage blocking member 51 are illustrated in Figs. 6A to 6D. Figs. 6A to 6D each are a sectional view taken along the arrow VI-VI of Fig. 5, and depiction of the liquid column header 21 and the like is 20 omitted. Figs. 6A to 6C illustrate cases where the circumferential wall 6 is rectangularly tubular, and Fig. 6D illustrates a case where the circumferential wall 6 is cylindrical. Fig. 6A illustrates triangular passage blocking members 51A
25
covering four corners of the inner circumferential surface 7 of the circumferential wall 6, respectively, Figs. 6B and 6D illustrate passage blocking members 51B and 51D covering the entire circumference near the circumferential wall 6 (close to the inner circumferential surface 7), and Fig. 6C illustrates a passage blocking member 51C that is a combination of Figs. 6A and 6B. 5
[0054]
According to the present embodiment, since the passage blocking member 51 is provided to the circumferential edge portion of the internal space 3 where straight passage of a flue gas is likely to occur, the flue gas that is discharged from the absorption tower 50 without coming into gas-liquid contact with the cleaning 10 liquid can be reduced, and the desulfurization performance and the dust removal performance can be further improved.
[0055]
Note that the present invention is not limited to the embodiments and the modified examples described above as an example, and various changes are 15 possible in accordance with design or the like as long as such changes are within the scope not departing from the technical concept according to the present invention even when they are different from the embodiments or the like described above.
[Reference Signs List] 20
[0056]
1, 50: absorption tower
2: absorption tower body
26
3: internal space
8: flue gas introduction port
9: inlet duct (flue gas introduction part)
10: flue gas discharge port
11: outlet duct (flue gas discharge part) 5
12: mist eliminator
13: liquid reservoir part (absorption tower tank)
14: lower subspace
15: upper subspace
16: gas-liquid contact region 10
16A: first gas-liquid contact region
16B: second gas-liquid contact region
20: liquid column nozzle
21: liquid column header (liquid column tube)
22: first cleaning liquid circulation line 15
23: first circulation pipe
24: first circulation pump
25, 35: valve
26: liquid column
27: liquid column reachable point (top of spout) 20
28: liquid column-divided droplet group
30: spray nozzle
31: spray header (spray tube)
27
32: second cleaning liquid circulation line
33: second circulation pipe
34: second circulation pump
36: liquid film
37: liquid film-divided droplet group (spray-divided droplet group) 5
51, 51A, 51B, 51C, 51D: passage blocking member
D1: droplet distribution in a liquid column
D2: droplet distribution in a spray
F: flue gas flow direction
H1: height of a liquid column nozzle 10
H2: height of a spray nozzle
H3: height of the upper end edge of a flue gas introduction port
H4: height of the liquid column reachable point (the highest reachable height of a liquid column)
H5: occurrence height of a liquid film-divided droplet group

I/We Claim:
1. An absorption tower for a desulfurizer configured to absorb and remove sulfur oxide in a flue gas by using a cleaning liquid, the absorption tower comprising:
an absorption tower body having an internal space through which a flue 5 gas flows from below to above;
a liquid column nozzle provided in the internal space and configured to jet a cleaning liquid upward in a liquid column form; and
a spray nozzle provided in the internal space above the liquid column nozzle and configured to jet a cleaning liquid downward in a conical form, 10
wherein the spray nozzle is a hollow cone nozzle having an annular spraying pattern and is arranged at a height position that is higher than the highest reachable height of a liquid column formed of the cleaning liquid jetted from the liquid column nozzle,
wherein immediately after jetted, the cleaning liquid jetted from the spray 15 nozzle spreads in a liquid film form and then drops, and the liquid film is divided into liquid film-divided droplet groups as the cleaning liquid drops, and
wherein the liquid column nozzle is arranged at a height position that is lower than an occurrence height of the liquid film-divided droplet groups of the cleaning liquid jetted from the spray nozzle. 20
2. The absorption tower for a desulfurizer according to claim 1, wherein the liquid column nozzle is arranged at a height position at which a liquid column 29
formed of the cleaning liquid jetted from the liquid column nozzle does not interfere with the liquid film of the cleaning liquid jetted from the spray nozzle.
3. The absorption tower for a desulfurizer according to claim 1, wherein the occurrence height of the liquid film-divided droplet groups of the cleaning liquid 5 jetted from the spray nozzle is higher than the highest reachable height of the liquid column formed of the cleaning liquid jetted from the liquid column nozzle.
4. The absorption tower for a desulfurizer according to any one of claims 1 to 3 further comprising a spray header extending substantially horizontally so as to 10 transverse the internal space and configured to support the spray nozzle and supply a cleaning liquid to the spray nozzle,
wherein the absorption tower body has a circumferential wall shaped in a tube erecting substantially vertically,
wherein an inner circumferential surface of the circumferential wall 15 defines the internal space,
wherein a flue gas introduction port into which a flue gas flows is provided to the circumferential wall, and
wherein a passage blocking member protruding from the inner circumferential surface into the internal space is provided in at least a part of a 20 height range that is higher than or equal to an upper end edge of the flue gas introduction port and lower than or equal to the spray header in the inner circumferential surface of the circumferential wall.