JPH10118449A - Simple desulfurization apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a simple wet desulfurization apparatus capable of maintaining relatively higher gas flow rate, having a compact size, low being produced at low cost and being easy to install, by reducing the pressure loss of a gas stream in a desulfurization reactor. SOLUTION: A V-shape reactor 1 for introducing and returning a part of flue gas flowing inside a flue 2 is connected to a lower portion of the flue 2 leading to a stack 7. Spraying means 4 for spraying absorption liquid (spray liquid) to the flue gas introduced is provided to a flue gas introduction part of the reactor 1 and a spray liquid circulation pit 1b is provided at the lowest part of the reactor 1 for collecting the absorption liquid sprayed and for circulating the same to the spraying means 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a simple desulfurization apparatus for desulfurizing exhaust gas with a wet desulfurizing agent, and more particularly to a V-shaped reactor for introducing and returning a part of the exhaust gas flowing in a flue to the lower part of the flue. The present invention relates to a simple desulfurization apparatus for performing desulfurization by spraying a wet desulfurizing agent on exhaust gas in the reactor in the reactor.

[0002]

2. Description of the Related Art As one of the apparatuses for desulfurizing exhaust gas from a boiler or the like, there is a wet exhaust gas desulfurization apparatus for desulfurizing sulfur oxides in exhaust gas by spraying an absorbent containing a wet desulfurizing agent into exhaust gas in an absorption tower. .

FIG. 3 shows a conventional wet-type simple desulfurization apparatus 20. The conventional simple desulfurizer 20 is provided at an appropriate position of a flue 23 connecting an upstream fuel combustion means (boiler or the like) (not shown) and a downstream chimney (not shown) and connected to the flue 23. Can be

[0004] The conventional simple desulfurization apparatus 20 has, as a main component, a desulfurization reactor in which sulfur oxides in exhaust gas are absorbed by an absorbent containing a wet desulfurizing agent (lime or the like) to perform desulfurization. It includes a vertical absorption tower 21 and a fan 22 for gas suction provided in a flue 23 downstream of the absorption tower 21. An upstream flue 23 for introducing exhaust gas is connected to a lower portion of the absorption tower 21, while a downstream flue 23 is connected to the top of the absorption tower 21.

Absorbing liquid spraying means 26 for spraying the absorbing liquid is installed at the upper part of the absorption tower 21.
A mist eliminator 25 is installed just above 6 as shown. In the lower part of the absorption tower 21, a liquid reservoir 21a
Is formed, and the dropped absorbent is returned from the liquid reservoir 21a to the absorbent spraying means 26 via the motor 29, and is repeatedly sprayed. Liquid reservoir 21a
Include sulfites (CaSO
An oxidizing air supply means 27 for forcibly oxidizing ₃ ) is provided, and a dehydrator 30 for removing gypsum from desulfurized wastewater appropriately extracted and another wastewater treatment device (not shown) are connected.

The bypass 24 is provided with a wet exhaust gas desulfurization device so that the exhaust gas can flow without passing through the wet exhaust gas desulfurization device 20, that is, the gas flow can bypass the wet exhaust gas desulfurization device 20 in the event of an emergency failure or the like. The flue 23 on the upstream side and the downstream side of the device 20 is connected as shown in the figure. Dampers 28 and 31 for adjusting the amount of exhaust gas introduced into the bypass 24 are provided near the inlet of the bypass 24 and the outlet to the flue 23 as shown in the figure.

[0007] Exhaust gas containing sulfur oxides is introduced into the lower part of the absorption tower 21 through a flue 23 from a fuel combustion means. At this time, the bypass dampers 28 and 31 are controlled so as to be completely closed or opened as appropriate to recycle the gas on the downstream side.

The exhaust gas introduced into the lower part of the absorption tower 21 is
The liquid rises inside the vertical absorption tower 21 and comes into gas-liquid contact with the absorbing liquid sprayed from the absorbing liquid spraying means. As a result, the sulfur oxides in the exhaust gas are absorbed (desulfurized) by the absorbing solution, and gypsum (when the desulfurizing agent is lime) and the like are generated as in the following formula.

SO ₂ + CaCO ₃ → CaSO ₃ + CO ₂ (1) SO ₃ + CaCO ₃ → CaSO ₄ + CO ₂ (2) At this time, the fan 22 is driven, and the exhaust gas is absorbed.
Ascends quickly inside and drains into the flue. The desulfurized exhaust gas is then released to the atmosphere via other processing equipment. On the other hand, the absorbing liquid in gas-liquid contact with the exhaust gas falls into the liquid reservoir 21a, is returned to the absorbing liquid spraying means 26 via the pump 29, and is sprayed again. Thereafter, this process is repeated. At this time, the oxidizing air is supplied to the liquid reservoir 21a by the oxidizing air supplying means 27. As a result, sulfites such as CaSO ₃ generated by the above formula (1) are forcibly oxidized to gypsum or the like. The absorption liquid in the liquid reservoir 21a is appropriately extracted as desulfurization wastewater, and after being subjected to a treatment such as removal of gypsum by the dehydrator 30, is discharged.

[0010]

However, in the case of the conventional simple desulfurization apparatus of the wet type as described above, since the structure of the desulfurization reactor (absorption tower) is a vertical type, a pressure loss of the gas flow occurs, and As a result, the gas flow rate in the reactor was relatively small (3-4 m / s), and there was a problem in terms of desulfurization efficiency.

[0011] In order to achieve a high desulfurization capacity, the reactor becomes large, and inevitably the bypass connecting upstream and downstream sides (upstream and downstream) becomes long, resulting in high construction cost. .

Accordingly, an object of the present invention is to provide a wet type which can maintain a relatively large gas flow rate by reducing the pressure loss of a gas flow in a desulfurization reactor, is compact in size, has a low construction cost, and is easy to install. To provide a simple desulfurization device.

[0013]

In order to achieve the above object, a first aspect of the present invention is to provide a V-shaped reactor in which a part of exhaust gas flowing through the flue is introduced and returned to a lower portion of the flue leading to the chimney. And a spray means for spraying an absorbing liquid (spray liquid) on the introduced exhaust gas is provided in the exhaust gas introduction section of the reactor,
A spray liquid circulation pit for collecting the sprayed absorbing liquid and circulating the absorbing liquid to the spraying means is provided at the lowermost portion of the reactor. The invention of claim 2 is characterized in that the cross section of the wind tunnel of the downstream inclined portion of the reactor downstream of the spray liquid circulation pit is reduced by the wind tunnel of the upstream inclined portion of the reactor upstream of the spray liquid circulation pit. It is configured to be larger than the area.

[0014]

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

As an apparatus for easily desulfurizing exhaust gas containing sulfur oxides discharged from a boiler or the like using a wet desulfurizing agent, there is a simple wet desulfurization apparatus.

FIG. 1 is a schematic side sectional view of a simple (despite wet type) desulfurizer 15 of the present invention. This simple desulfurization device 15 is connected at an appropriate position in the flue 2 connecting the fuel combustion means (boiler or the like) on the upstream side (not shown) and the chimney 7 on the downstream side as shown in the figure below the flue 2. Provided. FIG. 2 is a schematic plan view of the simple desulfurization device 15.

As shown in the figure, the simple desulfurizer 15 of the present invention has a V-shaped reactor 1, and the reactor 1 is an inclined portion on the upstream side, and constitutes the left half of the “V” shape. A side inclined portion 1a, a spray liquid circulation pit 1b as a liquid reservoir connected to a lower end of the upstream inclined portion 1a, and a downstream inclined portion, which constitutes the right half of the "V" shape and has a spray liquid. And a downstream inclined portion 1c whose lower end is connected to the circulation pit 1b.

The downstream tunnel 1c of the reactor 1 is configured such that the cross-sectional area of the wind tunnel is larger than the upstream tunnel 1a.

The upper end (upstream end) of the upstream inclined portion 1a is connected to a lower portion of the flue 2 as an inlet for exhaust gas into the reactor 1. On the other hand, the upper end (downstream end) of the downstream inclined portion 1c is
As an outlet for the desulfurized exhaust gas to the flue 2, it is connected to an appropriate position of the flue 2 (it is of course downstream from the connection point of the upstream inclined portion 1 a to the flue 2). .

At an appropriate position near the inlet of the upstream inclined portion 1a, a spraying means 4 for spraying an absorbent (spray liquid) containing a wet absorbent (lime or the like) into exhaust gas is provided.
One end of a spray liquid circulation line 5 is connected to the spray means 4. On the other hand, the other end of the spray liquid circulation line 5 is connected to the spray liquid circulation pit 1b so that the spray liquid in the pit can be pumped out. The spray liquid circulation line 5 is provided with a circulation spray pump 6 for pumping the spray liquid in the spray liquid circulation pit 1b to the spray means 4.

The spray liquid circulation pit 1b is connected to an absorbing liquid supply means 10 for appropriately supplying an absorbing liquid, and an oxidizing air for forcibly oxidizing a product (CaSO ₃ or the like) requiring an oxidation treatment. The blower 8 is connected. The spray liquid circulation pit 1b is also connected to a dehydrator 9 for removing gypsum from desulfurization wastewater appropriately extracted and another wastewater treatment device (not shown).

The flue gas is supplied to the flue 2 at an appropriate position between a connection point (inlet) with the upstream slope 1a and a connection point (discharge port) with the downstream slope 1c. A bypass damper 3 for appropriately controlling is provided.

Exhaust gas containing sulfur oxides discharged from a boiler or the like is introduced into the stack 2, and the introduced exhaust gas flows in the stack 2 toward the chimney 7. At this time, the bypass damper 3 is completely closed. Then, the exhaust gas naturally flows into the upstream inclined portion 1 a of the reactor 1, rises on the downstream inclined portion 1 c through the space above the spray liquid circulation pit 1 b, and is discharged to the flue 2.

At this time, the absorbing liquid containing the wet absorbent (lime or the like) is sprayed from the spraying means 4 in the same direction as the exhaust gas, that is, in a cocurrent flow (at this time, a part of the absorbing liquid is changed in the opposite direction to the exhaust gas). I.e., countercurrent spraying). Thereby, sulfur oxides, that is, SO ₂ and SO ₃ , in the exhaust gas passing through the upstream inclined portion 1a are absorbed by the absorbing solution (that is, combined with the wet desulfurizing agent contained in the absorbing solution), and the desulfurization is performed. Done. For the desulfurization reaction at this time, refer to the above formulas (1) and (2). Absorbing liquid (spray liquid) containing gypsum etc. generated by this desulfurization reaction
Is dropped into the spray liquid circulation pit 1b, is again introduced into the spray means 4 through the spray liquid circulation line 5 by the circulation spray pump 6, and is sprayed. Thereafter, this process is repeated. The spray liquid circulation pit 1b is appropriately replenished with the absorbing liquid by the absorbing liquid supply means 10.

In the above process, the oxidizing air is fed into the absorbing liquid in the spray liquid circulation pit 1b by the oxidizing air blower 8, and the products (C
aSO ₃ ) is forcibly oxidized. Further, the absorbent in the spray liquid circulation pit 1b is appropriately extracted as desulfurization wastewater, and after being subjected to processing such as removal of gypsum by the dehydrator 9, is discharged.

That is, in the simple desulfurization apparatus 15 of the present invention, by closing the bypass damper 3, the exhaust gas containing the sulfur oxide is naturally introduced into the reactor 1 from the inlet thereof, and the exhaust gas is first inclined upstream. While descending the portion 1a, the absorbing liquid is sprayed by the spraying means 4 to be desulfurized. The desulfurized exhaust gas passes through the upper space of the spray liquid circulation pit 1b, rises on the downstream inclined portion 1c by inertia, returns to the flue 2, and is discharged to the atmosphere through other processing devices. On the other hand, the absorbing liquid (spray liquid) containing products such as gypsum generated by the desulfurization reaction falls into the spray liquid circulation pit 1b, and is again introduced into the spray means 4 through the spray liquid circulation line 5 to be reused. Is done.

Now, in the simple desulfurization apparatus 15 of the present invention, the cross-sectional area of the wind tunnel of the downstream inclined section 1c is changed to the upstream inclined section 1a.
, The pressure loss of the gas flow in the reactor 1 can be minimized. Further, since the spraying of the absorbing liquid in the spraying means 4 is basically performed in the co-current direction with respect to the gas flow, the spray liquid does not hinder the flow of the gas flow. Rather, this co-current spray exerts a gas drawing force, and the gas flow more easily flows through the reactor 1 (note that
In the case of a conventional absorption tower 21, the absorption liquid is always sprayed in countercurrent to the gas flow). As described above, since the pressure loss is minimized and the co-current spray is used, the conventional simple desulfurization apparatus 2 is used.
No special gas suction means such as the zero suction fan 22 (see FIG. 3) is required in the simple desulfurizer 15 of the present invention. In other words, an existing fan (FDF or IDF) on the upstream side is sufficient for exhaust gas suction, and no special gas suction means is required. Therefore, costs can be reduced both in terms of equipment and operation.

Most of the fine droplets (mist) generated by the spraying of the absorbing liquid from the spraying means 4 are collected when the exhaust gas collides with the liquid reservoir surface of the spraying liquid circulation pit 1b by inertia force. However, even if a part of the mist is taken along the gas flow into the downstream inclined portion 1c, the mist naturally returns to the spray liquid circulation pit 1b due to gravity due to the shape of the downstream inclined portion 1c. Therefore, in the simple desulfurization device 15 of the present invention, there is no fear that the absorbing liquid (spray liquid) flows out together with the exhaust gas.

In this embodiment, it is assumed that the bypass damper 3 is completely closed.
Of course, the state of the bypass damper 3 is not limited to this.

That is, the opening degree of the bypass damper 3 may be freely selected in a range from fully closed to fully open. If the bypass damper 3 is fully closed, all of the exhaust gas is introduced into the simple desulfurization device 15 as described above. Further, according to the degree of opening of the bypass damper 3 and the strength of the circulating spray flow, the amount of exhaust gas introduced into the simple desulfurization device 15 can be reduced, and the exhaust gas can be guided to the chimney without any treatment. . Conversely, a process mechanism may be provided which has an effect such that the exhaust gas discharged from the simple desulfurization device 15 flows backward in the flue 2 and is again introduced into the simple desulfurization device 15.

As described above, in short, the simple desulfurization apparatus 1 of the present invention
According to No. 5, a V-shaped reactor and a liquid reservoir (pit) are provided at the lower part of the flue toward the chimney, and the absorption liquid is sprayed in parallel with the gas flow, thereby reducing the size of the device and reducing the size of the device. The pressure loss of the gas stream at the can be minimized. Accordingly, a small installation space can be achieved, and the suction fan that was conventionally required can be omitted, and the desulfurization device can be easily and inexpensively installed in a narrow space around the existing flue.
In particular, it can be expected to spread in developing countries.

[0032]

As described above, in summary, according to the simple desulfurization apparatus of the present invention, a V-shaped reactor and a liquid reservoir (pit) are provided at the lower part of the flue toward the chimney, and the absorbing liquid is supplied to the gas flow. Basically, co-current spraying makes it possible to reduce the size of the apparatus and minimize the pressure loss of the gas flow in the apparatus. Therefore, a small installation space can be achieved, and a suction fan that has been conventionally required can be omitted, and the desulfurization device can be easily and inexpensively installed in a narrow space around the existing flue.

[Brief description of the drawings]

FIG. 1 is a schematic side sectional view of a simple wet desulfurization apparatus of the present invention.

FIG. 2 is a schematic plan view of the simple desulfurization device of FIG.

FIG. 3 is a schematic view of a conventional wet simple desulfurization apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Reactor 1b Spray liquid circulation pit 2 Flue 4 Spray means 7 Chimney

Claims (2)

[Claims] 1. A V-shaped reactor for introducing and returning a part of the exhaust gas flowing through the flue is connected to a lower portion of the flue leading to the chimney. Providing a spraying means for spraying the absorbing liquid (spray liquid),
A simple desulfurization apparatus, wherein a spray liquid circulation pit for collecting the sprayed absorbing liquid and circulating the absorbing liquid to the spraying means is provided at the lowermost part of the reactor. 2. A cross-sectional area of a wind tunnel of a downstream inclined portion of the reactor downstream of the spray liquid circulation pit is smaller than a cross-sectional area of an upstream inclined portion of the reactor upstream of the spray liquid circulation pit. The simple desulfurization apparatus according to claim 1, which is large.