JPS61287422A - Structure of self-supporting desulfurization tower - Google Patents

Abstract

PURPOSE:To prevent an absorption liquid from contamination into a cooling liquid and to obtain the stable desulfurization performance by providing a perforated plate to the vertical face of the gas passing part of the collector of the absorption liquid. CONSTITUTION:After an exhaust gas contg. SOx is introduced into a desulfurization tower 1 and cooled with a cooling liquid fed from a spray 12, SOx is absorbed with a limestone slurry fed from a spray 5 and the slurry is collected in the collectors 8. A gas dispersion plate 7 consisting of a perforated plate is provided in the vertical direction between the collectors 8 made to a gas passage and the absorption liquid is prevented from the contamination into the cooling liquid by the pressure difference of the upstream and downstream of gas in the gas dispersion plate 7. Since the collectors 8 and the dispersion plate 7 are positioned on the same plane, the resistance of the flow path is added and the breathing phenomena of gas are prevented.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a so-called free-standing desulfurization tower, and more particularly to an absorption device for a free-standing desulfurization tower in a wet limestone-gypsum flue gas desulfurization system. It is something.

[Prior art and problems to be solved] A self-supporting desulfurization tower has a gas cooling section and an absorption section within one tower in order to remove sulfur oxides contained in exhaust gas from a boiler etc. This involves spraying limestone slurry, which is an absorbent for sulfur oxides.

(+) , No. 6 Yt shows a conventional self-supporting desulfurization tower structure.

In the figure, the desulfurization tower 1 is a self-supporting cylindrical body that has a cooling liquid spray nozzle 12, a collector 8, a gas distribution plate 7, an absorption liquid spray nozzle 5, and a demister 6 inside, and has a structure in which the cooling liquid is stored at the bottom. It has become.

As shown by arrow g in FIG. 6, exhaust gas containing sulfur oxides is introduced from the lower side of the desulfurization tower 1. On the other hand, a coolant circulation pump 10 and a coolant circulation pipe 11 provided outside the desulfurization tower 1 spray the coolant stored at the bottom of the desulfurization tower 1 into the gas from a coolant spray nozzle 12 to cool the gas. At the same time, some of the sulfur oxides in the gas are removed.

The exhaust gas cooled at the bottom of the desulfurization tower 1 passes through the collector 8 and the gas distribution plate 7, and then an absorption liquid is sprayed from the absorption liquid spray nozzle 5 at the top of the tower, and the sulfur oxides contained are absorbed into the absorption liquid. . The absorption liquid is supplied from the absorption liquid circulation tank 2 to the absorption liquid spray nozzle 5 by an absorption liquid circulation pump 3 and absorption liquid circulation piping 4 provided outside the tower.

The exhaust gas that absorbs sulfur oxides into the absorption liquid is transferred to a demister.
After the entrained mist is removed in step 6, the duct (
(not shown) and is discharged as clean gas.

The absorption liquid that is sprayed into the exhaust gas from the absorption liquid spray nozzle 5 and absorbs the sulfur oxides in the gas falls and passes through the gas distribution plate 7, and then is collected by the collector 8, and then passed through the downcomer pipe 9. The absorbent liquid returns to the absorption liquid circulation tank 2 provided outside the tower and is stored in the tank 2 for a certain period of time to recover the pH. After that, as mentioned above, once again, the absorption liquid circulation pump 3
, is sprayed into the desulfurization tower l by the absorption liquid circulation pipe 4 and the absorption liquid spray nozzle 5.

In addition, part of the cooling liquid sprayed from the cooling liquid spray nozzle 12 evaporates to lower the temperature of the exhaust gas flowing into the tower, and also absorbs a part of the sulfur oxides in the gas and stores them at the bottom of the tower. It falls into the liquid and is collected. After being stored for a certain period of time to recover the pH, the coolant is again sprayed into the inflow exhaust gas in the desulfurization tower 1 by the coolant circulation pump 10, the coolant circulation pipe 11, and the coolant spray nozzle 12, as described above.

The absorption liquid sprayed into the desulfurization tower 1 as described above is supplied to the absorption liquid circulation tank 2, where fresh limestone slurry is
(CaCO3) is supplied, and the liquid composition of the entire cooling liquid is maintained at a constant value by blowing a part of the absorption liquid into the stored cooling liquid at the bottom of the tower using the absorption liquid circulation piping 4. It is configured as follows. On the other hand, as mentioned above, the absorption liquid blown into the stored cooling liquid at the bottom of the tower is used as a cooling liquid to cool the introduced flue gas and absorb some of the sulfur oxides. It is used to achieve a pH suitable for air oxidation of absorbed and produced calcium sulfite. In addition, by injecting air into this stored coolant, the calcium sulfite in the coolant is oxidized and converted into gypsum, and a part of it is sent from the coolant circulation pipe 11 to a gypsum recovery facility to recover by-product gypsum. It is a system.

Note that since the cooling liquid and the absorption liquid are slurry liquids, a stirrer is provided in each liquid storage section to prevent the solid content from being washed away.

The waste dispersion plate 7 installed in the center of the desulfurization tower 1 prevents uneven flow by providing resistance by providing a perforated plate in the gas flow path against the uneven flow that occurs as a result of gas being introduced into the tower from the side. It has a role. The collector 8 is installed in order to exhibit the required desulfurization performance by distributing and collecting both the absorption and cooling liquids, which have different compositions as described above.

FIG. 7 shows a cross section of the desulfurization tower 1 taken along the line AA in FIG. 6, and shows the arrangement of the gas distribution plate 7 and the collector 8. FIG. 8 is a view taken along line BB in FIG. 7, and FIG. 9 shows a partially enlarged view.

As shown in FIG. 9, the absorbent liquid is collected in the collector 8 and rises between the gas tray 1 and the collector 8. Note that the gap B' of the collector 8 is designed to be smaller than the width B of the collector 8. FIG. 10 shows an example of the shape of the collector 8 which has been improved to prevent the absorption liquid from falling into the cooling liquid stored at the bottom of the tower.

In the desulfurization tower configured as described above, if the absorption liquid flows into the cooling liquid in an amount larger than the amount υ that is blown from the absorption circulation pipe 4 into the stored cooling liquid at the bottom of the tower, the desulfurization performance will decrease. Efforts have been made to prevent the collector portion 8 from entering the stored coolant. However, in the conventional desulfurization tower 1, collectors 8 are installed above and below to form a gas flow path, and a gas distribution plate 7 is installed above the collectors 8 (on the downstream side for gas flow). Therefore, it is impossible to prevent absorption liquid from being mixed into the cooling liquid due to the gas breathing phenomenon, and it has the disadvantage that it is difficult to maintain guaranteed desulfurization performance due to its structure.

The purpose of the present invention is to eliminate the drawbacks of the desulfurization tower of the conventional structure described above, and to provide a highly reliable free-standing type that has structurally stable desulfurization performance without absorbing liquid leaking into the cooling liquid in a part of the collector. To provide a desulfurization tower structure.

[Means for solving problems]

In a self-supporting desulfurization tower, the present invention replaces the gas distribution plate, which in conventional structures was installed downstream of the collector to provide resistance to the gas flow and prevent gas drift, to the vertical surface of the gas passage section of the collector. It was designed to be installed.

The present invention will be explained in detail below based on illustrated embodiments.

〔Example〕

The desulfurization tower of the present invention has the schematic structure shown in FIG. 1, but its reaction system is similar to that of the conventional desulfurization tower shown in FIG. 6, so a detailed explanation will be omitted.

FIG. 3 is a diagram further viewed from DD in FIG. 2 showing the cross section of the desulfurization tower 1 seen from C-c in FIG. 1.

In the present invention, as shown in FIG. 3, a gas dispersion plate 7 made of a perforated plate is installed in the lead m direction between upper and lower collectors 8 having gas flow paths.

As shown in FIG. 4, a short bus prevention plate 13 is provided at the end of the collector 8 to prevent a gas short bus.

As shown in FIG. 1, by changing the inclination angle α of the upper and lower collectors 8 and the gas distribution plate 7, it is possible to control the effective area of the gas distribution plate 7 with respect to the gas flow and the effect of preventing unbalanced flow. Further, as shown in FIG. 3, the area of the gas distribution plate 7, which was constant in the conventional structure, can be changed by adjusting the vertical distance H between the upper and lower collectors 8, and the width B and the gap B of the collectors 8. can be adjusted to increase or decrease the number of vertical planes.

According to the desulfurization tower 1 having this structure, as shown in FIG. 5, in contrast to the conventional structure in which the absorbed liquid leaked and mixed into the stored cooling liquid, a perforated plate is used in the collector 8 section and a gas distribution plate is installed. As a result, the absorption liquid can be prevented from being mixed into the cooling liquid due to the gas pressure difference between the upstream and downstream sides of the gas distribution plate 7, and the collector 8 and the gas distribution plate 7 are on the same plane. Therefore, it is possible to prevent flow path resistance from being added to the gas flow at the collector 8, and the gas suffocation phenomenon at the collector 8.

Although the above embodiments have been explained using an example of a self-supporting cylindrical desulfurization tower, the present invention does not limit the column cross section of the self-supporting desulfurization tower, and may be applied to, for example, a prismatic desulfurization tower. Needless to say, similar effects can be obtained.

〔Effect of the invention〕

As is clear from the above detailed description, according to the present invention, the following effects can be obtained.

(1) Since it is possible to prevent the absorption liquid from leaking into the cooling liquid in a part of the collector, reliability in terms of performance of the desulfurization tower is improved.

(2) Since the area of the gas distribution plate can be set freely,
It is possible to minimize Δp in the gas distribution plate, lower the discharge pressure of the desulfurization fan, and save energy.

(3) Even if the area required for gas passage through the gas distribution plate changes, the aperture ratio and dimensions of the perforated plate used for the gas distribution plate can be kept the same by adjusting the number of collectors. , the necessary area can be secured.

(4) Since it is possible to change the angle of the gas distribution plate with respect to the gas flow by changing the inclination of the collector, it is possible to further improve the effect of preventing gas drift, thereby increasing the reliability in terms of performance of the desulfurization tower. will improve.

(5) The internal structure of the column is simplified and no gas distribution plate support is required, which improves economic efficiency.

[Brief explanation of the drawing]

FIG. 1 is a side view showing a schematic structure of a self-supporting desulfurization tower according to an embodiment of the present invention, FIG. 2 is a view taken from CC in FIG. 1,
Figure 3 is a view taken from the line D-D in Figure 2, Figure 4 is a perspective view of the end of a part of the collector of the self-supporting desulfurization tower shown in Figure 1, and Figure 5 is a view of the end of a part of the collector of the self-supporting desulfurization tower shown in Figure 1. An explanatory diagram showing the state in which gas passes through the provided gas distribution plate, FIG. 6 is a cross-sectional view showing the schematic structure of a self-supporting desulfurization tower with a conventional structure, and FIG.
Figure 8 is a diagram seen from B-B in Figure 7, and Figure 9 is an explanatory diagram showing the state of the absorbed liquid and passing gas in a part of the collector of the self-supporting desulfurization tower shown in Figure 6. , FIG. 1O is a diagram showing a collector having a shape different from the collector shape shown in FIG. 9. l...Desulfurization tower, 2...Absorption liquid circulation tank, 3...
Absorption liquid circulation pump, 4... Absorption liquid circulation piping, 5...
Absorbent spray nozzle, 6... Demister-57... Gas distribution plate, 8... Collector, 9... Downpipe, 10
...Cooling liquid circulation pump, 11...Cooling liquid circulation piping,
12...Cooling liquid spray nozzle, 13...Short path prevention plate.

Claims (1)

[Claims] (1) In order to remove sulfur oxides from combustion exhaust gas from boilers, etc., a self-supporting desulfurization tower uses limestone as an absorbent and has dust removal, absorption, and oxidation functions in one tower. A free-standing desulfurization tower structure characterized by a perforated plate installed on the vertical surface of the gas passage section of the absorption liquid collector.