JP2003190739A - Wet-type flue-gas desulfurization equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide wet-type flue-gas desulfurization equipment which, when a rotary heat exchanger is used, can increase the flow rate of gas without unnecessarily increasing the internal volume of a circulation tank and can realize low cost of equipment and low operation cost. <P>SOLUTION: In the wet-type flue-gas desulfurization equipment, an outlet duct 3 is disposed just above an inlet duct 2. A partition plate 14 constitutes a face common to the outlet duct 3 and the inlet duct 2. The partition plate 14 is once extended horizontally into a gas absorbing part, is then bent downward, and is extended in this direction into a circulation tank 6 to such a height that is not below the surface of a liquid. Exhaust gas introduced through the inlet duct 2 first forms a downward flow in the gas absorption part, is passed through between the leading end of the partition plate 14 and the liquid surface, then ascends through an upward flow region 16 provided with spray nozzles 13 to remove sulfur oxide contained in the waste gas, and is then discharged through the outlet duct 3 disposed just above the inlet duct 2. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust gas treating apparatus for removing harmful components in exhaust gas, and in particular, an inlet duct and an outlet duct are integrated to facilitate connection to a rotary heat exchanger. The present invention relates to a two-chamber wet flue gas desulfurization device.

[0002]

2. Description of the Related Art An absorption tower in a conventional two-chamber wet flue gas desulfurization apparatus is shown in FIG. This wet flue gas desulfurization apparatus mainly includes an absorption tower main body 1, an inlet duct 2, an outlet duct 3, an absorbing liquid circulation pump 4, a circulation tank 6, an agitator 7, an air blowing pipe 8, a mist eliminator 9, and an absorbing liquid discharge pipe. 10, a circulation pipe 11, a spray header 12, a spray nozzle 13, a partition plate 14, an ascending flow region 16, a descending flow region 15, and the like. A plurality of spray nozzles 13 are installed in a cross section orthogonal to the gas flow, and a plurality of spray nozzles 13 are installed in the gas flow direction. Further, the agitator 7 and the air blowing pipe 8 are installed in the circulation tank 6 in which the absorbing liquid stays,
The mist eliminator 9 is installed in the outlet duct 3.

Exhaust gas discharged from a boiler (not shown) is introduced into the absorption tower body 1 from the inlet duct 2 in a substantially horizontal direction by a desulfurization fan (not shown), and is discharged from the outlet duct 3.

In most of the absorption towers of the spray system, the exhaust gas introduced from the lower part of the absorption tower is discharged from the top of the tower in order to bring the exhaust gas and the absorbent into countercurrent contact. Since the plate 14 is installed and the outlet duct 3 is provided at almost the same height as the inlet duct 2, the exhaust gas introduced from the inlet duct 2 is blocked by the partition plate 14 and rises in the ascending flow region 16, and the tower top After reversing at, the descending flow region 15 is descended.

In the meantime, in the ascending flow region 16 and the descending flow region 15, the absorption liquid containing calcium carbonate sent from the absorption liquid circulation pump 4 is sprayed from the spray nozzle 13 provided in each region to absorb the absorption liquid and the exhaust gas. Gas-liquid contact is performed. At this time, the absorbing liquid selectively absorbs sulfur oxide (SO ₂ ) in the exhaust gas and forms calcium sulfite. The absorption liquid that has generated calcium sulfite is temporarily stored in the circulation tank 6, and while being stirred by the oxidizing stirrer 7, the oxygen in the air supplied from the air blowing pipe 8 oxidizes the calcium sulfite to generate calcium sulfate (gypsum). To do.

A part of the absorbing liquid 5 in the circulation tank 6 in which calcium carbonate and gypsum coexist is sent to the spray nozzle 13 again by the absorbing liquid circulating pump 4, and a part of the absorbing liquid is discharged from the absorbing liquid withdrawing pipe 10 (not shown). It is sent to the processing and gypsum recovery system. Further, among the absorbing liquids atomized by the spray from the spray nozzle 13, those having a small droplet diameter are entrained in the exhaust gas, but are collected by the mist eliminator 9 provided in the outlet duct 3.

In this prior art, since the outlet duct 3 is provided at the same height as the inlet duct 2, the mist eliminator 9 and the supporting duct (not shown) of the outlet duct 3 are low and simple, In addition, the length of the duct for connecting to a heat exchanger (reheating side) not shown can be short.

However, in this prior art, the inlet duct 2 and the outlet duct 3 are basically arranged on the opposite wall surfaces of the absorber main body, and a heat recovery device arranged on the inlet duct 2 side as a heat exchanger is used. This is not suitable when using a rotary heat exchanger in which the reheaters arranged on the side of the outlet duct 3 are arranged so as to be adjacent to each other. When the rotary heat exchanger is used in the absorption tower structure shown in FIG. 5, as shown in FIG. 6, for example, the inlet duct 2 is extended to the vicinity of the outlet duct 3 and the heat recovery unit 18 is arranged in the vicinity thereof. It is necessary to use a rotary heat exchanger 17 with a reheater 19 arranged in the outlet duct 3 of.

Therefore, when the heat exchanger is a rotary heat exchanger, the inlet duct 2 and the outlet duct 3 shown in FIG. 7 are used.
However, a general one-chamber type wet flue gas desulfurization device located on the same wall surface of the absorption tower body 1 is often adopted. However, in recent years, there has been a strong demand for a wet flue gas desulfurization apparatus in which the tower diameter is reduced for cost reduction and the gas flow rate in the tower is increased for improving desulfurization performance.

However, when high-sulfur coal is burned,
As shown in FIG. 7, the SO ₂ concentration at the inlet of the absorption tower becomes high, and in order to secure the residence time required for the oxidation in the circulation tank 6 that corresponds to that, as shown in FIG. Often, the diameter of 6 must be increased. However, there is a structural limit to the ratio of the diameter of the circulation tank 6 to the diameter of the spray portion, and if a tank volume larger than that is required, the liquid depth must be increased. Therefore, it is necessary to increase the height of the circulation tank 6, resulting in an increase in equipment cost and an increase in the blower power of the oxidizing air introduced into the absorbing liquid from the air blowing pipe 8.

[0011]

In the above-mentioned conventional technique, the two-chamber type wet flue gas desulfurization apparatus is adapted to the rotary heat exchanger 17, and the one-chamber type wet flue gas desulfurization apparatus has a high concentration SO ₂ exhaust gas condition. There was a problem that the equipment cost and the power of the oxidizing air blower increased, because the high gas flow rate at the plant was not fully considered.

An object of the present invention is, when a rotary heat exchanger is used, a wet exhaust having a low equipment cost and a low operating cost that can achieve a high gas flow rate without increasing the capacity of the circulation tank more than necessary. To get a smoke desulfurizer.

[0013]

The above problems of the present invention are as follows.
A circulation tank that stores the absorbing liquid, an inlet duct that introduces the exhaust gas discharged from the combustion device such as a boiler above the circulating tank, and the exhaust gas introduced from the inlet duct and the absorbing liquid are brought into gas-liquid contact, and sulfur oxidation in the exhaust gas In a wet flue gas desulfurization apparatus provided with an absorption tower having a gas absorbing part for absorbing a substance into an absorbing liquid and an outlet duct for discharging the gas purified from the gas absorbing part, the inlet duct and the outlet duct are horizontally arranged. The wet flue gas desulfurization device is provided with a facing gas flow path, which is provided adjacent to the absorption tower so as to be vertically overlapped with each other, and the adjoining portions of the inlet duct and the outlet duct are constituted by a common partition member.

The partition member disposed adjacent to the inlet duct and the outlet duct is a horizontal portion for partitioning the inlet duct and the outlet duct, and vertically in the gas absorbing portion of the absorption tower to a position above the liquid level in the circulation tank. It can be configured to include an extended vertical portion.

Further, there is provided a heat medium rotary heat exchanger in which a heat recovery device arranged in the inlet duct for lowering the exhaust gas temperature and a reheater arranged in the outlet duct for increasing the exhaust gas temperature are arranged next to each other. Is installed.

Further, the inlet duct is provided in the absorption tower so as to form a downward flow area of the gas introduced into the absorption tower, and the outlet duct is formed so as to form an upward flow area of the gas discharged from the inside of the absorption tower. May be provided in the absorption tower, the gas absorption section may be provided with a spray nozzle, and the gas absorption section may be provided in an upward flow region of gas in the absorption tower connected to the outlet duct section.

Further, it is possible to install a spray nozzle which constitutes a gas absorbing portion also in the downward flow region of the gas.

[0018]

According to the present invention, a heat recovery device (on the inlet duct side) is provided by installing a partition plate for partitioning the outlet duct and the inlet duct.
And the reheater (outlet duct side) can be installed adjacent to each other in the exhaust gas duct section, and the duct work can be facilitated.

Further, in the present invention, the gas absorption section in the absorption tower in which the spray nozzle is arranged is provided in the absorption tower on the side to which the outlet duct is connected, and the horizontal sectional area of the gas absorption section and the inlet duct are A circulation tank having a total horizontal cross-sectional area of the absorption tower horizontal cross-sectional area facing the absorption tower can be installed. Therefore, a circulation tank having the same horizontal cross-sectional area as the total horizontal cross-sectional area can be provided. Therefore, even if the horizontal cross-sectional area of the gas absorption portion is reduced to increase the gas flow velocity, the horizontal cross-sectional area of the circulation tank is sufficiently increased by increasing the horizontal cross-sectional area of the portion where the inlet duct faces the absorption tower. Of the exhaust gas at the inlet of the absorption tower
Even when the SO ² concentration is relatively high, the capacity of the circulation tank can be increased without increasing the liquid depth of the circulation tank.

Thus, it is not necessary to deepen the liquid depth in the circulation tank in order to secure the residence time of the absorbing liquid that has absorbed the exhaust gas in the circulation tank, and thus a large-capacity circulation tank having a relatively large horizontal cross-sectional area can be provided. No need to install. Therefore, desulfurization can be performed with high efficiency without increasing the equipment cost and increasing the power of the oxidizing air blower.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a side sectional view of an absorption tower of a wet flue gas desulfurization apparatus according to an embodiment of the present invention. This wet flue gas desulfurization apparatus is mainly used in the absorption tower main body 1, like the apparatus described in the related art. Inlet duct 2, outlet duct 3,
Absorption liquid circulation pump 4, circulation tank 6, stirrer 7, air blowing pipe 8, mist eliminator 9, absorption liquid extraction pipe 1
0, circulation pipe 11, spray header 12, spray nozzle 13, partition plate 14, upflow region 16 and downflow region 15
Etc. A plurality of spray nozzles 13 are installed in a cross section orthogonal to the gas flow, and a plurality of spray nozzles 13 are installed in the gas flow direction. Further, the agitator 7 and the air blowing pipe 8 are installed in the circulation tank 6 in which the absorbing liquid 5 stays, and the mist eliminator 9 is installed in the outlet duct 3. Exhaust gas discharged from a boiler (not shown) is introduced from the inlet duct 2 into the absorber main body 1 in a substantially horizontal direction by a desulfurization fan (not shown), and is discharged from the outlet duct 3.

The inlet duct 2 and the outlet duct 3 are connected to the top of the absorber main body 1, and a partition plate 14 is provided above the inlet duct 2.
The outlet duct 3 is disposed through the partition plate 14, the partition plate 14 has an upper end connected to the absorption tower body 1, and a lower end arranged in a bent shape so as not to rush into the liquid surface in the circulation tank 6,
1 is a side view of an absorption tower in which an inlet duct 2 and an outlet duct 3 are integrated via a partition plate 14.

FIG. 2 shows the inlet duct 2 of the absorption tower in FIG.
And the heat recovery device 18 of the rotary heat exchanger 17 in the outlet duct 3.
The structure in which the (inlet duct side) and the reheater 19 (outlet duct side) are tied together is shown.

The exhaust gas introduced from the inlet duct 2 in the above-mentioned absorption tower structure is bent downward by the partition plate 14 and descends in the downward flow region 15, so that the lower end of the partition plate 14 and the liquid level in the circulation tank 6 are brought into contact with each other. After passing through the space, the ascending flow region 16 in which the spray nozzle 13 is arranged rises and is discharged from the outlet duct 3. Therefore, the rotary heat exchanger 1 in which the heat recovery unit 18 arranged in the middle of the inlet duct 2 and the reheater 19 arranged in the middle of the outlet duct 3 are arranged adjacent to each other
7 can be used.

As described above, in the example shown in FIGS. 1 and 2, since the inlet duct 2 and the outlet duct 3 are vertically stacked with the partition plate 14 interposed therebetween, the inlet duct 2 and the outlet duct 3 are arranged.
The rotary heat exchanger 17 can be installed in a proper place, and duct work becomes easy.

In the absorption tower shown in FIGS. 1 and 2, the spray section (gas absorption section) in the absorption tower main body 1 in which the spray nozzle 13 is arranged is connected to the outlet duct 3 so that the spray section is horizontally disconnected. It is possible to install a circulation tank 6 having a total horizontal cross-sectional area of the area and the horizontal cross-section of the inlet duct 2 which faces the absorption tower. Therefore, the horizontal cross-sectional area of the circulation tank 6 can be increased even if the horizontal cross-sectional area of the spray portion is reduced to increase the gas flow velocity. Therefore, even when the SO ² concentration in the exhaust gas at the absorption tower inlet is relatively high, The volume of the circulation tank 6 can be increased without increasing the liquid depth of 6.

Thus, it is not necessary to deepen the liquid depth in the circulation tank 6 in order to secure the residence time of the absorbing liquid 5 that has absorbed the exhaust gas in the circulation tank 6, and therefore it is necessary to install the large-capacity circulation tank 6. Absent. Therefore, desulfurization can be performed with high efficiency without increasing the equipment cost and increasing the power of the oxidizing air blower.

FIG. 3 is a side sectional view of an absorption tower according to another embodiment of the present invention, showing an inlet duct 2 provided at the top of the absorption tower.
The outlet duct 3 is arranged on the lower side of the partition plate 14 via the partition plate 14.

Further, the example shown in FIG. 4 is different from the embodiment shown in FIG. 1 in that the spray nozzle 13 is also arranged in the downward flow region 15 of the exhaust gas introduced from the inlet duct 2 of the absorption tower. Since the downflow region 15 has a high gas velocity condition,
The absorption efficiency of sulfur oxide (SO ₂ ) is high, and if the spray nozzle 13 is arranged so that the absorbing liquid 5 is jetted in the same direction as the gas flow in the downward flow region 15 as in the present embodiment, the absorbing liquid 5 is is injected at a low pressure loss than in upflow region 16, it is possible to obtain high desulfurization performance is used as a rough cut of the SO ₂ in the SO ₂ concentration is high condition in the exhaust gas in the absorption tower inlet be able to.

As described above, in the above embodiment of the present invention, a part of the wall surface of the inlet duct 2 and a part of the wall surface of the outlet duct 3 are shared by one member, and the inlet duct 2 and the outlet duct 3 are shared. Since they are integrated, the number of duct members can be reduced and the facility cost can be reduced. In addition, FIG.
As described above, in the above-described embodiment, it is not necessary to deepen the liquid depth in the circulation tank 6 to secure the retention time of the absorbing liquid that has absorbed the exhaust gas in the circulation tank 6, and thus the large-capacity circulation tank 6 Need not be installed. Therefore, desulfurization can be performed with high efficiency without increasing the equipment cost and increasing the power of the oxidizing air blower.

Although the horizontal cross-sectional shape of the absorption tower body 1 in the above-mentioned embodiment is assumed to be circular,
Even if it is a square type, almost the same effect can be obtained.

Further, in the present embodiment, there is no restriction on the ratio of the horizontal cross-sectional area of the circulation tank 6 to the horizontal cross-sectional area of the gas absorption portion in which the spray nozzle 13 in the absorption tower is arranged, and the diameter of the circulation tank 6 can be freely set. Therefore, it is possible to increase the capacity of the circulation tank 6 without deepening the liquid depth in the circulation tank 6 even under the condition that the concentration of SO ₂ in the exhaust gas at the inlet of the absorption tower is high. There is no increase in equipment cost and power of the oxidizing air blower. Therefore, it can be said that the above-described embodiment has an optimum absorption tower structure in the plant in which the rotary heat exchanger is adopted.

[0033]

According to the present invention, even when a rotary heat exchanger is used, a high gas flow velocity can be achieved without increasing the horizontal cross-sectional area of the circulation tank more than necessary, and the facility cost can be reduced. In addition, it is possible to obtain a wet flue gas desulfurization device with low operating cost.

[Brief description of drawings]

FIG. 1 is a side sectional view of an absorption tower structure in which an inlet duct and an outlet duct according to an embodiment of the present invention are integrated.

FIG. 2 is a configuration diagram in which rotary heat exchangers are arranged in the inlet duct and the outlet duct of the embodiment of FIG.

FIG. 3 is a side sectional view of an absorption tower structure in which an inlet duct and an outlet duct of the embodiment according to the present invention are integrated.

FIG. 4 is a side sectional view of an absorption tower structure in which a spray nozzle is also arranged in a downflow region of the absorption tower connected to the inlet duct according to the embodiment of the present invention.

FIG. 5 is a side sectional view of a conventional two-chamber absorption tower structure.

6 is a configuration diagram in which rotary heat exchangers are arranged in an inlet duct and an outlet duct of the two-chamber absorption tower structure of FIG.

FIG. 7 is a side sectional view of the most common one-chamber type wet flue gas desulfurization apparatus of the prior art.

[Explanation of symbols]

1 Absorption tower main body 2 Entrance duct 3 Outlet duct 4 Absorbing liquid circulation pump 5 absorption liquid 6 circulation tank 7 Stirrer 8 Air blowing tube 9 Mist eliminator 10 Absorption liquid extraction pipe 11 Circulation piping 12 Spray header 13 Spray nozzle 14 Partition plate 15 Downflow area 16 Upflow area 17 Rotary heat exchanger 18 Heat recovery device 19 Reheater

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Motoomi Iwatsuki             Babcock Hitachi 3-36 Takaracho, Kure City, Hiroshima Prefecture             Kure Institute Co., Ltd. (72) Inventor Takanori Nakamoto             Babcock Hitachi 6-9 Takaracho, Kure City, Hiroshima Prefecture             Kure Office Co., Ltd. F-term (reference) 4D002 AA02 AC01 BA02 CA01 DA05                       DA16 EA12 FA03                 4D020 AA06 BA02 BA09 BB03 CB27                       CC09

Claims (5)

[Claims] 1. A circulation tank for storing absorbing liquid, an inlet duct for introducing exhaust gas discharged from a combustion device such as a boiler above the tank, and the exhaust gas introduced from the inlet duct and the absorbing liquid are brought into gas-liquid contact with each other. In a wet flue gas desulfurization apparatus provided with an absorption tower having a gas absorbing part for absorbing sulfur oxides in exhaust gas into an absorbing liquid and an outlet duct for discharging purified gas from the gas absorbing part, an inlet duct and an outlet The duct is provided with a gas flow path that is oriented in the horizontal direction, and is provided in the absorption tower so as to be vertically stacked and adjacent to each other.
A wet flue gas desulfurization device, wherein the inlet duct and the outlet duct are adjacent to each other and are configured by a common partition member. 2. The partition member disposed adjacent to the inlet duct and the outlet duct is a horizontal portion for partitioning the inlet duct and the outlet duct, and vertically above the liquid level in the circulation tank in the gas absorption section of the absorption tower. The wet flue gas desulfurization apparatus according to claim 1, wherein the wet flue gas desulfurization apparatus comprises a vertical portion extending up to the point. 3. A heat medium rotary heat exchanger in which a heat recovery device arranged in the inlet duct to lower the exhaust gas temperature and a reheater arranged in the outlet duct to raise the exhaust gas temperature are arranged next to each other. The wet flue gas desulfurization apparatus according to claim 1 or 2, which is installed. 4. The inlet duct is provided in the absorption tower so as to form a downward flow area of the gas introduced into the absorption tower, and the outlet duct is formed so as to form an upward flow area of the gas discharged from the inside of the absorption tower. 4. The absorption tower is provided in the absorption tower, the spray nozzle is provided in the gas absorption section, and the gas absorption section is provided in an upflow region of gas in the absorption tower connected to the outlet duct section. 5. The wet flue gas desulfurization device according to any one of 1. 5. The wet flue gas desulfurization apparatus according to claim 1, further comprising a spray nozzle that constitutes a gas absorbing portion is installed in the downflow region of the gas.