JP7524308B2 - Absorption tower of desulfurization equipment - Google Patents

Description

The present invention relates to an absorption tower of a desulfurization device that removes sulfur oxides from exhaust gas.

For example, exhaust gas discharged from a combustion engine such as a boiler contains air pollutants such as sulfur oxides ( _SOx ). Methods for reducing the amount of _SOx contained in exhaust gas include wet desulfurization methods that absorb and remove _SO2 (sulfur dioxide gas) using a cleaning liquid (absorption liquid) such as an alkaline aqueous solution or an absorbent slurry.

As a desulfurization device using the above-mentioned wet desulfurization method, a liquid column type absorption tower is known that cleans exhaust gas by spraying cleaning liquid upward (see, for example, Patent Document 1). In a liquid column type absorption tower, cleaning liquid sprayed from a liquid column nozzle forms a liquid column above the liquid column nozzle. After forming the liquid column, the cleaning liquid disperses at the top of the spray and then descends, colliding with the cleaning liquid sprayed up from the liquid column nozzle and being atomized. The atomized cleaning liquid comes into gas-liquid contact with the exhaust gas and absorbs air pollutants contained in the exhaust gas. In addition, soot contained in the exhaust gas can be removed from the exhaust gas by the atomized cleaning liquid.

Japanese Patent Application Publication No. 10-128053

In recent years, there has been a trend toward stricter regulations on emissions of air pollutants such as sulfur oxides and particulate matter. Emissions of air pollutants can be reduced by using high-quality fuels, such as low-sulfur fuels that have a low sulfur content and low-particulate fuels that produce less particulate matter when burned.

However, the use of expensive, high-quality fuels increases operating costs, so there is a demand to use cheaper fuels such as high-sulfur fuels with a high sulfur content or high-dust fuels that produce a lot of soot when burned, and there is a demand for improved desulfurization and dust removal performance.

Therefore, the present invention aims to provide an absorption tower of a desulfurization equipment that can improve desulfurization performance and dust removal performance.

In order to achieve the above object, the first aspect of the present invention is an absorption tower of a desulfurization device that absorbs and removes sulfur oxides in exhaust gas with 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 exhaust gas flows from below to above. The liquid column nozzle is provided in the internal space and sprays the cleaning liquid in the form of a liquid column upward. The spray nozzle is provided in the internal space above the liquid column nozzle and sprays the cleaning liquid in a cone shape downward. The spray nozzle is a hollow cone nozzle with a circular spray pattern and is disposed at a height position above the maximum height of the liquid column formed by the cleaning liquid sprayed from the liquid column nozzle. The cleaning liquid sprayed from the spray nozzle spreads in the form of a liquid film immediately after spraying, and then as it falls, the liquid film breaks up to form a liquid film split droplet group. The liquid column nozzle is disposed at a height position below the generation height of the liquid film split droplet group of the cleaning liquid sprayed from the spray nozzle.

In the first aspect, a liquid column nozzle that sprays the cleaning liquid upward in the form of a liquid column is provided in the internal space of the absorption tower body, and a spray nozzle that sprays the cleaning liquid downward in a cone shape is provided at a position in the internal space above the position where the liquid column nozzle is provided. Therefore, compared to an absorption tower equipped with only either a liquid column nozzle or a spray nozzle, the range in which the cleaning liquid and the exhaust gas can come into gas-liquid contact (gas-liquid contact range) is expanded in the direction of exhaust gas flow. Therefore, desulfurization performance and dust removal performance can be improved compared to an absorption tower equipped with only either a liquid column nozzle or a spray nozzle.

The spray nozzle is a hollow cone nozzle with a circular spray pattern, and the cleaning liquid sprayed from the spray nozzle spreads out as a liquid film immediately after being sprayed, and then as it falls, the liquid film breaks up to form a group of droplets due to liquid film breakup. The spray nozzle is disposed at a height position above the maximum height reached by the liquid column formed by the cleaning liquid sprayed from the liquid column nozzle, and the liquid column nozzle is disposed at a height position below the generation height of the group of droplets due to liquid film breakup of the cleaning liquid sprayed from the spray nozzle, so that interference between the droplets from the liquid column nozzle and those from the spray nozzle can be suppressed, and desulfurization performance and dust removal performance can be further improved.

In the absorption tower of the first aspect of the present invention, the liquid column nozzle is arranged at a height position such that the liquid column formed by the cleaning liquid sprayed from the liquid column nozzle does not interfere with the liquid film of the cleaning liquid sprayed from the spray nozzle.

In the first aspect, there is no interference between the liquid column formed by the cleaning liquid sprayed from the liquid column nozzle and the liquid film of the cleaning liquid sprayed from the spray nozzle, so that it is possible to prevent a decrease in desulfurization performance caused by bias of the cleaning liquid due to interference between the liquid column and the liquid film.

In the absorption tower of the first aspect of the present invention, the height at which the liquid film breakup droplet group of the cleaning liquid sprayed from the spray nozzle is generated is higher than the maximum reach height of the liquid column formed by the cleaning liquid sprayed from the liquid column nozzle, the cleaning liquid which has formed the liquid column breaks up and falls from the maximum reach height of the liquid column to become a liquid column breakup droplet group, and the particle size distribution of the liquid column breakup droplet group is larger than the particle size distribution of the liquid film breakup droplet group .

In the first aspect, the generation height of a group of liquid film breakup droplets of the cleaning liquid sprayed from the spray nozzle is higher than the maximum reach height of the liquid column formed by the cleaning liquid sprayed from the liquid column nozzle, so that interference between the droplets from the liquid column nozzle and the droplets from the spray nozzle can be further suppressed.

A second aspect of the present invention is an absorption tower according to the first aspect, which includes a spray header extending substantially horizontally across the internal space, supporting the spray nozzle, and supplying a cleaning liquid to the spray nozzle. The absorption tower body has a cylindrical peripheral wall standing substantially vertically. The inner peripheral surface of the peripheral wall defines the internal space. The peripheral wall is provided with an exhaust gas inlet through which exhaust gas flows in. A slip-through prevention material protruding from the inner peripheral surface into the internal space is provided on at least a portion of the inner peripheral surface of the peripheral wall in a height range above the upper edge of the exhaust gas inlet and below the spray header.

In the second aspect, a slip-through prevention material is provided on the outer peripheral edge portion of the internal space where the exhaust gas is likely to slip through, so that the amount of exhaust gas discharged from the absorption tower without gas-liquid contact with the cleaning liquid can be reduced, and the desulfurization performance and dust removal performance can be further improved.

According to the present invention, desulfurization performance and dust removal performance can be improved.

1 is a cross-sectional view showing a schematic configuration of an absorption tower according to a first embodiment of the present invention. 1 is a conceptual diagram of droplet distribution in a liquid column and droplet distribution in a spray. 1A and 1B are schematic diagrams illustrating the dispersion of a droplet group jetted from a liquid column nozzle and the dispersion of a droplet group jetted from a spray nozzle; 1A and 1B are schematic diagrams showing interference between a droplet group sprayed from a liquid column nozzle and a droplet group sprayed from a spray nozzle, in which FIG. 1A shows a state in which they interfere, and FIG. 1B shows a state in which they do not interfere. FIG. 4 is a cross-sectional view showing a schematic configuration of an absorption tower according to a second embodiment of the present invention. 6 is a cross-sectional view taken along the line VI-VI in FIG. 5, showing several examples of the slip-through prevention material.

First Embodiment
An absorption tower 1 of a desulfurization apparatus according to a first embodiment of the present invention will be described with reference to Figs. 1 to 4. The desulfurization apparatus is a wet limestone-gypsum flue gas desulfurization apparatus that removes sulfur oxides from exhaust gas containing sulfur oxides generated in a combustion apparatus (not shown) by absorbing them with a cleaning liquid (absorption liquid), and includes an absorption tower 1 into which exhaust gas containing sulfur oxides is introduced. Combustion apparatuses include boilers such as those in thermal power plants, as well as engines such as diesel engines, gas turbine engines, and steam turbine engines. The outline arrow F in the figures indicates the flow direction of the exhaust gas.

(Configuration of Absorption Tower)
As shown in Fig. 1, the absorption tower 1 includes an absorption tower body 2 having an internal space 3 into which exhaust gas from a combustion device is introduced. The absorption tower body 2 has a cylindrical peripheral wall 6 standing approximately vertically between a bottom surface 4 and a ceiling surface 5, and an internal space 3 extending in the vertical direction is defined by the bottom surface 4, the ceiling surface 5, and an inner peripheral surface 7 of the peripheral wall 6. The peripheral wall 6 may be cylindrical or rectangular tubular.

An exhaust gas inlet 8 is provided on one side (front side) of the peripheral wall 6, and an inlet duct (exhaust gas inlet section) 9 is connected to the exhaust gas inlet 8. An exhaust gas outlet 10 is provided on the upper part of the other side (rear side) of the peripheral wall 6 opposite the exhaust gas inlet 8, and an outlet duct (exhaust gas outlet section) 11 is connected to the exhaust gas outlet 10. At the exhaust gas outlet 10, the upper surface of the outlet duct 11 is continuous with the ceiling surface 5 of the absorption tower main body 2. The inlet duct 9 and the outlet duct 11 may be cylindrical or rectangular. The exhaust gas discharged from the combustion device is introduced into the internal space 3 from the exhaust gas inlet 8 through the inlet duct 9. The introduced exhaust gas flows from the bottom to the top of the internal space 3 and is discharged from the exhaust gas outlet 10 through the outlet duct 11.

In the internal space 3 of the absorption tower body 2, a liquid column header (liquid column tube) 21 equipped with at least one (multiple in this embodiment) liquid column nozzle 20 and a spray header (spray tube) 31 equipped with at least one (multiple in this embodiment) spray nozzle 30 are installed. The liquid column nozzle 20 is disposed above the upper edge of the exhaust gas inlet 8, and the spray nozzle 30 is disposed above the liquid column nozzle 20. That is, the height (injection port height) H1 of the liquid column nozzle 20 is higher than the height H3 of the upper edge of the exhaust gas inlet 8, and the height (injection port height) H2 of the spray nozzle 30 is higher than the height H1 of the liquid column nozzle 20 (H3 < H1 < H2). Each height is, for example, the height above ground from the ground on which the absorption tower body 2 is installed.

The liquid column nozzle 20 is configured to spray the cleaning liquid upward (in the same direction as the exhaust gas flow direction) in the form of a liquid column. The liquid column header 21 extends approximately horizontally across the internal space 3. The liquid column header 21 supports the liquid column nozzle 20 and supplies cleaning liquid to the liquid column nozzle 20. The arrangement pattern of the multiple liquid column nozzles 20 is not particularly limited, but it is preferable to arrange them evenly on the nozzle arrangement surface of the internal space 3.

The spray nozzle 30 is configured to spray the cleaning liquid downward (opposite the flow direction of the exhaust gas) in a cone shape. The spray header 31 extends approximately horizontally across the internal space 3. The spray header 31 supports the spray nozzle 30 and supplies cleaning liquid to the spray nozzle 30. The arrangement pattern of the multiple spray nozzles 30 is not particularly limited, but it is preferable to arrange them evenly on the nozzle arrangement surface of the internal space 3.

The spray nozzle 30 of this embodiment is a hollow cone nozzle with a circular spray pattern (hollow cone-shaped spray shape). The spray nozzle 30 is not limited to a hollow cone nozzle, and may be any nozzle that sprays cleaning liquid in a cone shape. For example, it may be another single-phase (one-fluid) nozzle such as a full cone nozzle that sprays a circular front shape, or a two-phase (two-fluid) nozzle that mixes gas and sprays cleaning liquid in the form of fine droplets.

The cleaning liquid may be, for example, a liquid containing an alkaline agent, seawater, etc. The alkaline agent may be, for example, CaCO ₃ , NaOH, Ca(OH) ₂ , NaHCO ₃ , Na2CO ₃ , etc.

The cleaning liquid sprayed from the liquid column nozzle 20 forms a liquid column 26 above the liquid column nozzle 20. The cleaning liquid that formed the liquid column 26 is dispersed at the highest reach position, the liquid column reach part (spray top) 27, as the upward penetration force and gravity are balanced, and then descends, colliding with the succeeding cleaning liquid sprayed up from the liquid column nozzle 20 and becoming finer. The droplet group (multiple droplets) of the finer cleaning liquid that falls as the liquid column 26 splits from the liquid column reach part 27 is called the liquid column split droplet group 28. The liquid column split droplet group 28 comes into gas-liquid contact with the exhaust gas and absorbs air pollutants such as _SOx (sulfur oxides) contained in the exhaust gas. The liquid column split droplet group 28 also removes soot contained in the exhaust gas from the exhaust gas.

The spray nozzle 30 is positioned above the maximum reach height (liquid column reach section 27) of the liquid column 26 formed by the cleaning liquid sprayed from the liquid column nozzle 20. That is, the height H4 of the liquid column reach section 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 reach section 27 (H1<H4<H2).

The cleaning liquid immediately after being sprayed from the spray nozzle 30 spreads in the form of a liquid film (a liquid film 36 spreads in the form of a hollow cone), and as it falls, the liquid film 36 breaks up into droplets. A group of droplets (a plurality of droplets) of the cleaning liquid that breaks up from the liquid film 36 and becomes finer is called a liquid film breakup droplet group (or a spray breakup droplet group) 37. The liquid film breakup droplet group 37 comes into gas-liquid contact with the exhaust gas and absorbs air pollutants such as _SOx (sulfur oxides) contained in the exhaust gas. The liquid film breakup droplet group 37 also removes soot contained in the exhaust gas from the exhaust gas.

The internal space 3 of the absorption tower body 2 is divided into a lower space 14 communicating with an inlet duct 9 via an exhaust gas inlet 8, an upper space 15 communicating with an outlet duct 11 via an exhaust gas outlet 10, a gas-liquid contact area 16 between the lower space 14 and the upper space 15, and a liquid pool 13 below the lower space 14. The gas-liquid contact area 16 is an area whose lower limit is the nozzle of the liquid column nozzle 20 and whose upper limit is the nozzle of the spray nozzle 30 (an area that is equal to or higher than the height of the nozzle of the liquid column nozzle 20 and equal to or lower than the height of the nozzle of the spray nozzle 30), and gas-liquid contact between the cleaning liquid and the exhaust gas is mainly performed in the gas-liquid contact area 16.

The gas-liquid contact area 16 is divided into a first gas-liquid contact area 16A below the height of the liquid column reach portion 27 of the liquid column 26 formed by the liquid column nozzle 20, and a second gas-liquid contact area 16B above the height position of the liquid column reach portion 27. That is, in the internal space 3, the upper space 15, the second gas-liquid contact area 16B, the first gas-liquid contact area 16A, the lower space 14, and the liquid pool portion 13 are arranged in order from the top. Gas-liquid contact between the cleaning liquid sprayed from the liquid column nozzle 20 and the exhaust gas occurs mainly in the first gas-liquid contact area 16A, and gas-liquid contact between the cleaning liquid sprayed from the spray nozzle 30 and the exhaust gas occurs mainly in the second gas-liquid contact area 16B.

Tiny liquid droplets entrained in the exhaust gas flow are removed by a mist eliminator 12 installed at the top of the absorption tower 1 (in this embodiment, the outlet duct 11). The gas (treated gas) from which the tiny liquid droplets have been removed by the mist eliminator 12 is heated as necessary by a reheating device (not shown) installed downstream of the absorption tower 1, and is discharged from a chimney (not shown). The mist eliminator 12 may also be installed in the upper space 15 of the absorption tower body 2.

The lower part of the internal space 3 of the absorber body 2 (the space below the lower space 14) constitutes a liquid pool (absorption tank) 13 for storing the cleaning liquid. The cleaning liquid is sprayed from the liquid column nozzle 20 and the spray nozzle 30, and after absorbing sulfur oxides by gas-liquid contact with the exhaust gas, it falls down the internal space 3 and is stored in the liquid pool 13. The liquid level (overflow level) of the cleaning liquid stored in the liquid pool 13 is set at a position lower than the lower end edge of the exhaust gas inlet 8. The cleaning liquid stored in the liquid pool 13 may contain reaction products generated by _SO2 absorbed from the exhaust gas and oxidation products generated by oxidation of the reaction products. The reaction products are, for example, sulfites generated by absorption of _SO2 into the cleaning liquid, and the oxidation products are, for example, gypsum. When oxidation products are generated, an air supply device (not shown) for supplying air to the stagnant cleaning liquid may be provided in the liquid pool 13.

The absorption tower 1 is equipped with 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 extract the cleaning liquid stored in the liquid pool 13 and send it to the liquid column nozzle 20 via the liquid column header 21. The second cleaning liquid circulation line 32 is configured to be able to extract the cleaning liquid stored in the liquid pool 13 and send it to the spray nozzle 30 via the spray header 31. The absorption tower 1 may also be equipped with a cleaning liquid introduction line (not shown) that introduces the cleaning liquid from outside the absorption tower body 2 into the liquid pool 13.

The first cleaning liquid circulation line 22 includes at least one first circulation pipe 23 connecting the liquid pool 13 and the liquid column header 21, a first circulation pump 24 provided in the middle of the first circulation pipe 23, and a valve 25 capable of opening and closing the first circulation pipe 23 upstream of the first circulation pump 24. The first circulation pump 24 extracts the cleaning liquid stored in the liquid pool 13 and sends it to the liquid column nozzle 20 via the first circulation pipe 23 and the liquid column header 21. The valve 25 may be an opening/closing valve or a flow rate adjustment valve. In addition, instead of or in addition to the valve 25, a valve capable of opening and closing the first circulation pipe 23 may be provided downstream of the first circulation pump 24.

The second cleaning liquid circulation line 32 includes at least one second circulation pipe 33 connecting the liquid pool 13 and the spray header 31, a second circulation pump 34 provided in the middle of the second circulation pipe 33, and a valve 35 capable of opening and closing the second circulation pipe 33 upstream of the second circulation pump 34. The second circulation pump 34 extracts the cleaning liquid stored in the liquid pool 13 and sends it to the spray nozzle 30 via the second circulation pipe 33 and the spray header 31. The valve 35 may be an opening/closing valve or a flow rate adjustment valve. In addition, instead of or in addition to the valve 35, a valve capable of opening and closing the second circulation pipe 33 may be provided downstream of the second circulation pump 34.

In the internal space 3 of the absorption tower 1, a first gas-liquid contact area 16A formed by the liquid column nozzle 20 and a second gas-liquid contact area 16B formed by the spray nozzle 30 are arranged in the direction of exhaust gas flow, and the first gas-liquid contact area 16A and the second gas-liquid contact area 16B form a gas-liquid contact area 16. As described below, the droplet group from the liquid column nozzle 20 in the first gas-liquid contact area 16A and the droplet group from the spray nozzle 30 in the second gas-liquid contact area 16B have different particle size distributions and droplet dispersions, and the gas-liquid contact rate is increased by the exhaust gas passing through both the first gas-liquid contact area 16A and the second gas-liquid contact area 16B.

(Expansion of droplet size distribution)
The relationship between the particle size distribution D1 of the droplet group sprayed and split from the liquid column nozzle 20 (droplet distribution in the liquid column) and the particle size distribution D2 of the droplet group sprayed from the spray nozzle 30 (droplet distribution in the spray) will be described with reference to Fig. 2. In Fig. 2, the droplet distribution D1 in the liquid column is shown by a solid line, and the droplet distribution D2 in the spray is shown by a dashed line.

Figure 2 is a conceptual diagram of droplet distribution (particle size distribution) in the liquid column and droplet distribution (particle size distribution) in the spray. As shown in Figure 2, the droplet group generated by the splitting of the cleaning liquid sprayed from the spray nozzle 30 (spray split droplet group 37 in Figure 1) has a relatively small particle size distribution D2, while the droplet group generated by the splitting of the cleaning liquid sprayed from the liquid column nozzle 20 (liquid column split droplet group 28 in Figure 1) has a relatively large particle size distribution D1. Therefore, a droplet group with a wide particle size distribution can be generated in the internal space 3 of the absorption tower body 2 through which the exhaust gas flows.

(Dispersion of droplets)
As shown in Fig. 3, with the spray nozzle 30, droplets (spray split droplet group 37) tend to form on an extension line of the liquid film 36, while with the liquid column nozzle 20, droplets (liquid column split droplet group 28) tend to form vertically below the liquid column reach portion 27. The dispersion direction of the liquid column split droplet group 28 is indicated by arrow 40, and the dispersion direction of the spray split droplet group 37 is indicated by arrow 41 in Fig. 3. Since the dispersion direction of the liquid column split droplet group 28 and the dispersion direction of the spray split droplet group 37 differ in this way, the cleaning liquid droplet groups 28, 37 can be dispersed more evenly in the horizontal cross section of the internal space 3 (gas-liquid contact region 16) of the absorption tower body 2.

(Interference of droplet groups)
Fig. 4 is a schematic diagram showing interference between a liquid column split droplet group 28 and a liquid film split droplet group 37. Fig. 4(a) shows a state in which the liquid column reach portion 27 reaches the liquid film 36 and causes interference, and (b) shows a state in which the liquid column reach portion 27 does not reach the liquid film 36 and does not cause interference. In the absorption tower 1 of this embodiment in which the liquid column nozzle 20 and the spray nozzle 30 are combined, there is a concern about interference between the droplet groups. The following three points are thought to be the main concerns due to interference.

The first concern is droplet coalescence. When the liquid column split droplet group 28 and the spray split droplet group 37 coalesce, the droplets become coarse and the surface area of the droplet group decreases, which is disadvantageous in a flue gas desulfurization device that is in gas-liquid contact.

The second concern is the collision between droplets. Collisions between droplets include collisions between the liquid column split droplet group 28 and the liquid film split droplet group 37, collisions between the liquid column split droplet group 28 and the liquid film 36, and collisions between the liquid column 26 (liquid column reach portion 27) and the liquid film 36. For example, collisions with the liquid film 36 may cause the liquid column split droplet group 28 to be finely atomized by secondary atomization, and finer droplet groups are advantageous for gas-liquid contact. However, the fine droplet groups produced by secondary atomization are not necessarily uniformly dispersed in the internal space 3, and if the fine droplet groups are biased, gas-liquid contact may be disadvantageous and desulfurization performance may be reduced.

The third concern is increased pressure loss. In areas where interference occurs, the density of the droplets increases locally, and increased pressure loss leads to increased power.

In this embodiment, in order to prevent the above-mentioned interference from occurring, the height of the spray nozzle 30 relative to the liquid column nozzle 20 is set so that the generation height H5 of the liquid film splitting 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 reach portion 27, which is the maximum reach height of the liquid column 26 formed by the liquid column nozzle 20 (H4 < H5).

(Suppression of uneven flow of exhaust gas)
In a liquid column type absorber in which the cleaning liquid is sprayed only by the liquid column nozzle 20, the desulfurization performance is high in the type in which the mist eliminator is arranged horizontally in the vertical duct (outlet duct) extending upward from the internal space of the absorber body, while the desulfurization performance is decreased in the type in which the mist eliminator is arranged vertically in the horizontal duct (outlet duct) extending horizontally from the upper part of the internal space of the absorber body. This phenomenon is considered to be due to the fact that the latter type in which the outlet duct extends horizontally makes it easier for the exhaust gas to flow obliquely from the internal space toward the outlet duct (easier to cause drift). In contrast, in this embodiment, the cleaning liquid is sprayed from the spray nozzle 30 on the downstream side (upper side) of the internal space 3, so that drift of the exhaust gas toward the outlet duct 11 can be suppressed by the cleaning liquid sprayed from the spray nozzle 30. Therefore, in addition to improving the desulfurization performance, an increase in the flooding gas flow rate (compacting the tower cross-sectional area) and an increase in the dust removal performance can also be expected.

As described above, according to this embodiment, compared to liquid column type absorption towers and spray type absorption towers, it is possible to expand the gas-liquid contact area 16 in the direction of exhaust gas flow, generate droplets having a wide particle size distribution in the internal space 3 of the absorption tower body 2 through which the exhaust gas flows, and disperse the droplets with minimal bias in the horizontal cross section of the internal space 3, thereby improving desulfurization performance and dust removal performance.

In addition, the height of the spray nozzle 30 relative to the liquid column nozzle 20 is set so that the generation height H5 of the liquid film split 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 reach portion 27, which is the maximum reach height of the liquid column 26 formed by the liquid column nozzle 20. This makes it possible to suppress interference between the droplets from the liquid column nozzle 20 and the droplets from the spray nozzle 30, thereby further improving the desulfurization performance and dust removal performance.

In addition, by carrying out modification work on the liquid column type absorption tower to add a spray nozzle 30 and a configuration for spraying cleaning liquid from the spray nozzle 30 (such as a spray header 31 and a second cleaning liquid circulation line 32), and by carrying out modification work on the spray type absorption tower to add a liquid column nozzle 20 and a configuration for spraying cleaning liquid from the liquid column nozzle 20 (such as a liquid column header 21 and a first cleaning liquid circulation line 22), it is possible to improve desulfurization performance and dust removal performance.

Second Embodiment
Next, a second embodiment of the present invention will be described with reference to Figures 5 and 6. An absorption tower 50 of this embodiment is an absorption tower body 2 of the first embodiment provided with a slip-through prevention material 51, so that the same components as those of the first embodiment are denoted by the same reference numerals and description thereof will be omitted. Also, among the components of the absorption tower 1 of the first embodiment, components that are not directly related to this embodiment are not shown in the figures.

In a desulfurization device, desulfurization of exhaust gas is performed by gas-liquid contact with the cleaning liquid, so it is necessary to minimize the possibility of the exhaust gas passing upward through the internal space 3 of the absorption tower 1 without coming into contact with the absorption liquid. The wall edges (near the inner circumferential surface 7) and corners (for example, the four corners when the peripheral wall 6 is rectangular) of the absorption tower main body 2 are areas where exhaust gas is likely to pass through. In this embodiment, in order to prevent exhaust gas from passing through, anti-slip materials 51 that protrude from the inner circumferential surface 7 into the internal space 3 are provided at the outer peripheral edge of the internal space 3 where exhaust gas is likely to pass through (see Figure 5).

The height position at which the slip-through prevention material 51 is attached is above the upper edge of the exhaust gas inlet 8 and at least a part of the height range 53 below the spray header 31. For example, if the area is divided into a first area that is above the upper edge of the exhaust gas inlet 8 and in a height range below the liquid column header 21, and a second area that is above the liquid column header 21 and in a height range below the spray header 31, the slip-through prevention material 51 may be provided in only one of the areas, or in both areas. Also, multiple slip-through prevention materials may be provided in one area.

Examples of the shape of the slip-through prevention material 51 are shown in (a) to (d) of Figure 6. (a) to (d) of Figure 6 are cross-sectional views taken along the line VI-VI of Figure 5, with the liquid column header 21 and other elements omitted. (a) to (c) are views in the case where the peripheral wall 6 is rectangular tubular, and (d) is views in the case where the peripheral wall 6 is cylindrical. (a) is a triangular slip-through prevention material 51A that covers each of the four corners of the inner peripheral surface 7 of the peripheral wall 6, (b) and (d) are slip-through prevention materials 51B and 51D that cover the entire edge of the peripheral wall 6 (near the inner peripheral surface 7), and (c) is a slip-through prevention material 51C that combines (a) and (b).

According to this embodiment, anti-slip material 51 is provided on the outer peripheral edge of the internal space 3 where the exhaust gas is likely to slip through, so that the exhaust gas discharged from the absorption tower 50 can be reduced without gas-liquid contact with the cleaning liquid, thereby further improving the desulfurization and dust removal performance.

The present invention is not limited to the above-described embodiments and variants, which have been described as examples, and various modifications may be made depending on the design, etc., other than the above-described embodiments, etc., as long as they do not deviate from the technical concept of the present invention.

1, 50: Absorption tower 2: Absorption tower body 3: Internal space 8: Exhaust gas inlet 9: Inlet duct (exhaust gas inlet section)
10: Exhaust gas exhaust port 11: Exit duct (exhaust gas exhaust section)
12: Mist eliminator 13: Liquid pool (absorption tower tank)
14: Lower space 15: Upper space 16: Gas-liquid contact area 16A: First gas-liquid contact area 16B: Second gas-liquid contact area 20: Liquid column nozzle 21: Liquid column header (liquid column tube)
22: First cleaning liquid circulation line 23: First circulation piping 24: First circulation pump 25, 35: Valve 26: Liquid column 27: Liquid column arrival section (spray top)
28: Liquid column split droplet group 30: Spray nozzle 31: Spray header (spray tube)
32: Second cleaning liquid circulation line 33: Second circulation pipe 34: Second circulation pump 36: Liquid film 37: Liquid film split droplet group (spray split droplet group)
51, 51A, 51B, 51C, 51D: slip-through prevention material D1: droplet distribution in liquid column D2: droplet distribution in spray F: flow direction of exhaust gas H1: height of liquid column nozzle H2: height of spray nozzle H3: height of upper edge of exhaust gas inlet H4: height of liquid column reach part (maximum reach height of liquid column)
H5: Height of droplets generated by liquid film breakup

Claims (2)

An absorption tower of a desulfurization apparatus that removes sulfur oxides from exhaust gas by absorbing them with a cleaning liquid,
an absorption tower body having an internal space through which exhaust gas flows from below to above;
a liquid column nozzle provided in the internal space and configured to spray the cleaning liquid upward in the form of a liquid column;
a spray nozzle provided in the internal space above the liquid column nozzle and configured to spray the cleaning liquid downward in a cone shape;
the spray nozzle is a hollow cone nozzle having a circular spray pattern, and is disposed at a height position higher than a maximum height of a liquid column formed by the cleaning liquid sprayed from the liquid column nozzle;
The cleaning liquid sprayed from the spray nozzle spreads in the form of a liquid film immediately after being sprayed, and then the liquid film breaks up as it falls, forming a group of liquid film breakup droplets,
The liquid column nozzle is disposed at a height position lower than a height at which a liquid film breakup droplet group of the cleaning liquid sprayed from the spray nozzle is generated,
the liquid column nozzle is disposed at a height position such that a liquid column formed by the cleaning liquid sprayed from the liquid column nozzle does not interfere with a liquid film of the cleaning liquid sprayed from the spray nozzle;
a height at which a group of liquid film breakup droplets of the cleaning liquid sprayed from the spray nozzle is generated is higher than a maximum height of a liquid column formed by the cleaning liquid sprayed from the liquid column nozzle;
The cleaning liquid that has formed the liquid column splits off from the maximum height of the liquid column and falls to become a group of split droplets of the liquid column,
The particle size distribution of the liquid column breakup droplet group is larger than the particle size distribution of the liquid film breakup droplet group.
The absorption tower of a desulfurization equipment is characterized by the above. 2. The absorber tower of claim 1,
a spray header extending generally horizontally across the interior space to support the spray nozzle and supply cleaning fluid to the spray nozzle;
The absorption tower body has a cylindrical peripheral wall that stands substantially vertically,
An inner circumferential surface of the peripheral wall defines the internal space,
The peripheral wall is provided with an exhaust gas inlet through which exhaust gas flows,
an anti-slip material protruding from the inner circumferential surface into the internal space is provided on at least a portion of the inner circumferential surface of the peripheral wall in a height range above the upper edge of the exhaust gas inlet and below the spray header.

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