JPS6186922A - Wet exhaust gas treatment apparatus - Google Patents

Abstract

PURPOSE:To perform the removal of dust in low pressure loss with high effeciency, by mounting a primary cooling dust removal part, a secondary cooling dust removal part, a mixing part, a bypass flow passage for introducing a part of the exhaust gas from the primary cooling dust removal part into the mixing part and a gas flow control mechanism. CONSTITUTION:Exhaust gas is cooled in the primary cooling dust removal part A below a spray nozzle 110, while dust therein is removed, to be converted to high temp. saturated gas and a part thereof is introduced into an over- saturation part B through a bypass duct 121 and the remainder is introduced into the secondary cooling dust removal part C below a spray nozzle 112 and flowed upwardly as low temp. saturated gas and mixed with the high temp. saturated gas in an over-saturation part B to grow fine particles into coarse particles. A damper 131 regulates the amount of the high temp. saturated gas so as to obtain sufficient coarse particle forming effect. The particle- containing gas is passed through an absorbing part packed bed D and a mist catch part E to further remove dust therein.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a wet exhaust gas treatment device.

[Prior art and problems to be solved by the invention] In the case of a conventional wet exhaust gas treatment device, such as a flue gas deflow device,
In addition to absorbing gases such as sulfur oxides (SOX) and hydrogen sulfide (H(1)), many scrubbers also remove dust from the exhaust gas.To remove this dust, a wet scrubber is installed in the gas cooling section at the inlet. Note that the scrubber here refers to a device that removes impurities in gas using a liquid such as water.Therefore, a conventional wet exhaust gas treatment device will be explained with reference to FIG. 4. Reference numeral 1 in the figure indicates an absorption tower, and a duct 2 is connected to this absorption tower 1. Cooling water 3 is stored in the lower part of the absorption tower 1, and this cooling water is piped through a pump 4. 5 and 6, and are sprayed into the duct 2 and the absorption tower 1 through spray nozzles 7 and 8 connected to these pipes 5 and 6. In addition, the reference numeral a in the figure indicates a cooling dust removal section, and this cooling dust removal section a The cooling water 3 sprayed through the spray nozzle 8 cools the exhaust gas, removes dust, and also partially absorbs gas. Part b indicates a packed bed part for gas absorption;
Part of the dust removal is also carried out in this packed bed. Furthermore, part 0 is a mist removal part. A mist catch 9 is installed in the mist removing section C. In such a spray type scrubber, the pressure loss is usually 50 to 300M.
However, since the dust collection mechanism of the scrubber device relies on inertial collision between droplets and dust, the removal rate of particles of several μm to submicron drops sharply. Furthermore, when a Venturi scrubber is used, the overall dust removal efficiency is improved compared to the above-mentioned spray type, but the dust removal efficiency of submicron particles is lowered. In this case, the pressure loss should be 500 to 15
It is necessary to make it considerably large as 00sQ. Also, when considering the power aspect, it is not suitable for treating exhaust gas such as boiler exhaust gas, which has a large amount of gas.

The present invention has been made based on the above points, and an object thereof is to provide a wet exhaust gas treatment device with low pressure loss and high efficiency by improving the collection efficiency of submicron particles.

[Means for Solving the Problems] That is, the wet exhaust gas treatment device according to the present invention includes a primary cooling dust removal section that introduces exhaust gas and performs gas absorption and dust removal, and a primary cooling dust removal section that introduces exhaust gas that has passed through the primary cooling dust removal section and performs gas absorption and dust removal. A secondary cooling dust removal section that absorbs and removes dust; a bypass flow path that introduces a part of the exhaust gas that has passed through the primary cooling dust removal section to the downstream side of the secondary cooling dust removal section; A mixing section that mixes the high-temperature saturated gas introduced at It is characterized by comprising a gas amount adjustment mechanism that adjusts the mixing ratio of the saturated gas and the low-temperature saturated gas.

[Effect] In other words, in order to improve the collection efficiency of submicron particles, it is necessary to make the particles coarser by condensing the air above the water on the particle surface, and this condensation of water vapor on the particle surface is achieved. Possible methods for this include a steam suction method and a method of mixing high-temperature saturated gas and low-temperature saturated gas. The present invention realizes a method of mixing high-temperature saturated gas and low-temperature saturated gas, in which high-temperature saturated gas introduced from the primary cooling dust removal section via a bypass flow path and low-temperature saturated gas from the secondary cooling dust removal section are mixed. The purpose is to coarsen the fine particles by mixing them in one part. To explain this with reference to FIG. 4, a supersaturated state is created by mixing high temperature saturated gas 21 (temperature T2 and humidity H2) and low temperature saturated gas 22 (temperature T3 and humidity 1"3). (indicated by reference numeral 24 in the figure). This supersaturation state 24 is temporary. When the supersaturated state 24 changes to the saturated state 25, if a core particle exists, water vapor corresponding to the humidity (ΔH) condenses on the surface of the particle. This structure aims to make the particles coarser. Note that the point indicated by the reference numeral 20 in the figure indicates the inlet gas state of the wet exhaust gas treatment device, where the temperature is T1 and the humidity is Hl.

[Effects of the Invention] Therefore, fine particles can be effectively coarsened, thereby making it possible to significantly improve the collection efficiency of fine particles such as submicron particles.

[Embodiment] A first embodiment of the present invention will be described below with reference to FIG. FIG. 1 is a cross-sectional view showing a schematic configuration of a wet exhaust gas treatment apparatus according to this embodiment. In the figure, reference numeral 101 indicates an absorption tower, and a duct 102 is connected to this absorption tower 101. Cooling water 103 is accommodated within the absorption tower 101 . This cooling water 103 contains alkaline substances such as caustic soda and magnesium hydroxide.
This is intended to effectively absorb gases such as SOx and HC, 2, etc. In addition, the absorption tower 10
1 is connected to a pump 105 via a suction pipe 104. A discharge pipe 107+, t of this pump 105 is arranged to pass through the upper part of the absorption tower 101, and a spray nozzle 108 is connected to the tip thereof. Another discharge pipe 109 is branched and connected to the above-mentioned discharge pipe 107, and this discharge pipe 109 is arranged to penetrate through the upper part of the above-mentioned duct 102. At its tip is a spray nozzle 110
is connected. Further, another discharge pipe 111 is branched and connected to the discharge pipe 107, and this discharge pipe 1
11 is disposed to penetrate through the absorption tower 101 at a substantially intermediate position. A spray nozzle 112 for a secondary cooling dust removal section is connected to the tip of this discharge pipe 111. A heat exchanger 113 is inserted into the discharge pipe 111, and an external make-up water supply pipe 114 is connected thereto. A bypass duct 121 is provided between the duct 102 and the absorption tower 101.
is installed.

The position below the spray nozzle 11o of the duct 102 is a sub-cooling section A, and the exhaust gas introduced through the duct 102 is humidified and cooled in the sub-cooling system dust removing section A, and is cooled to about 60% by cooling. It becomes a high-temperature saturated gas with a temperature of about 'C, and dust removal and gas absorption are performed at this time. A part of the exhaust gas that has passed through the primary cooling dust removal section A is introduced into the supersaturation section B via the bypass duct 121. On the other hand, the remaining exhaust gas is introduced into a constricted section C below the spray nozzle 112 (this constricted section becomes a secondary cooling dust removal section).

In this secondary cooling dust removing section C, the water is cooled by the cooling water 103 sprayed from the spray nozzle 112, and the
It becomes a low temperature saturated gas of about ℃. At this time, the cooling water 103
External makeup water may be used instead. 0 except when it's 1
and gas absorption. The low-temperature saturated gas that has passed through the secondary cooling dust removal section C flows upward to the supersaturated section B.
flow inside. In this supersaturated portion B, the gas collides with the high-temperature saturated gas introduced through the bypass duct 121, and the two are mixed due to the difference in their respective pressures.

Through this mixing, fine particles are coarsened based on the principle described above. A damper 131 as a gas amount adjustment mechanism is installed in the bypass duct 121, and by automatically or manually adjusting the opening degree of this damper 131, gas is introduced into the absorption tower 101 through the bypass duct 121. The amount of hot saturated gas used is adjusted, thereby adjusting the mixing ratio of cold saturated gas and hot saturated gas. In addition, in order to obtain a sufficient grain coarsening effect, it is necessary to have an appropriate mixing ratio of low-temperature saturated gas and high-temperature saturated gas, and in particular, in the case of boilers, etc., it is necessary to adjust the mixing ratio to cope with the additional fluctuation. Appropriate controls are also required.

The exhaust gas containing coarse particles rises, passes through the absorption section filling layer X layer and the mist catch section E, and further flows upward. A mist catch 122 is installed in the mist catch section E.

At that time, the coarsened particles fill the absorption part! [') and is removed at the mist catch section E. In addition, the cooling water 10 is supplied from the spray nozzle 108 to the absorption section filling layer.
3 is sprayed.

As described above, according to the wet exhaust gas treatment device according to the present embodiment, by mixing low temperature saturated gas and high temperature saturated gas at an appropriate mixing ratio, fine particles such as submicron particles can be effectively inverted. As a result, it becomes possible to significantly improve the removal efficiency of submicron particles in the absorption section filling layer and the mist catch section E.

Next, a second embodiment will be described with reference to FIG.

That is, in the first embodiment, as the gas amount adjusting rock groove,
Although the damper 131 was used, in the case of this embodiment, an annular member 141 is arranged above the secondary cooling dust removal section with a gap as shown in the figure, and a circular ring is placed in the center of this annular member 141. 142 is placed.

This annular portion 142 is connected to a hydraulic unit 143 installed outside the absorption tower 101, and is configured to be slidable in the vertical direction. By moving the annular part 142 up and down, the distance between the annular member 141 and the throttle member 144 (throat part) forming the dust removal part C of the secondary cooling system is adjusted. The flow rate and the mixing ratio of the low temperature saturated gas and the high temperature saturated gas are adjusted. Further, the spray nozzle 112 is installed so as to be oriented upward. The other configurations are the same as those of the first embodiment, and their explanation will be omitted.

Therefore, it is possible to achieve the same effects as the first embodiment.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a wet exhaust gas treatment device showing a first embodiment of the present invention, FIG. 2 is a sectional view of a wet exhaust gas treatment device showing a second embodiment, and FIG. 3 is a detailed view of the wet exhaust gas treatment device of the present invention. FIG. 4, which is an explanatory diagram, is a cross-sectional view of a conventional wet exhaust gas treatment device. 101... Absorption tower, 102... Duct, 121...
・Bypass duct (bypass flow path), 131... Damper (gas amount adjustment mechanism), A... Primary cooling dust removal section, B...
... Supersaturation section, C... Secondary cooling dust removal section, D... Absorption filling section, E... Mist catch section. Applicant's Sub-Attorney Patent Attorney Takehiko Suzue No. 3 Suzue Namida 4121 Procedural Amendment 60/Rent-4 Showa Year 1999 Japanese Patent Office Commissioner Manabu Shiga 1, Patent Application for Indication of Case No. 1982-207026 2 , Relation to the case of the person who amended the name of the wet exhaust gas treatment device 3o Patent applicant <620) Mitsubishi Heavy Industries, Ltd. (2) Correct “Mist Catch 9” on page 3, line 3 of the specification to “Mist Catcher-9”. (3) Correct “Mist Catcher 9” on page 4, line 17 of the specification. "air" is corrected to "steam". (4) "Suction method" on page 4, line 20 of the specification is corrected to "-blow method". (5) "Blowing method" on page 5, line 6 of the specification is corrected. Figure 4” to “Figure 3”
I am corrected. (6) On page 5, line 15 of the specification, [J that is required in the configuration to be designed is corrected to "can be designed." (7) In the second line of page 9 of the specification, the word "helmet" is corrected to "particularly."

Claims (1)

[Claims] A primary cooling dust removal section that introduces exhaust gas and performs gas absorption and dust removal; a secondary cooling dust removal section that introduces the exhaust gas that has passed through the primary cooling dust removal section and performs gas absorption and dust removal; a bypass flow path that introduces a part of the exhausted exhaust gas to the downstream side of the secondary cooling dust removal section;
A mixing section that mixes the high-temperature saturated gas introduced through the bypass flow path and the low-temperature saturated gas that has passed through the secondary cooling dust removal section, and the primary cooling dust removal section and the secondary cooling dust removal section are provided. and a gas amount adjustment mechanism for adjusting the mixing ratio of the high-temperature saturated gas and the low-temperature saturated gas in the mixing section.