JPH0330810A - Method and apparatus for removing dust from gas - Google Patents

Abstract

PURPOSE:To improve dust removing efficiency by a method wherein the gas requiring its dust to be removed is supplied into the gas blow-off pipes together with a liq. and they are blasted in an atomized stream into the liq. with its ion concn. adjusted. CONSTITUTION:Exhaust gas Gw is blasted into water W through a number of blow-off pipes 4 with their ends 4A open under the water to produce fine air bubbles, thereby forming air bubble layers 7. The streams of the dust contg. exhaust gas Gw are diffused and impinged by inertia against one another in such air bubble layers 7 so as to remove the dusts therefrom. The blasting height H of the exhaust gas Gw is adjusted by the concn. and particle size of the dusts therein. The dust concn. of a gas G is automatically controlled by cascading to a controller for controlling the height H. In this way, the dust removing effect can be improved.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is a method of blowing a gas containing fine dust into a liquid, such as exhaust gas from a coal-fired boiler, by contacting a liquid with a gas. The present invention relates to a method and apparatus for removing dust from gas by generating bubbles to form a bubble layer and removing dust from the gas using fine bubbles.

[Prior Art] A method and a device for removing soot and dust contained in a continuously flowing gas by contacting a liquid with a gas in a wet type dust collector etc. There are two main types: liquid dispersion type, in which liquid is sprayed, and gas dispersion type, in which gas is dispersed as bubbles in liquid, such as in a bubble column.

So far, liquid dispersion type dust collectors have been put into practical use as high-performance wet dust collectors for processing large amounts of gas, such as for dust collection, but on the other hand, the gas-liquid contact rate depends on the operating conditions. However, it is generally said that the gas dispersion type is better.

Conventionally, gas-liquid contact devices have been developed as gas dispersion devices, which are vertical or horizontal devices that have many small holes on the sides that allow gas to be ejected into the liquid contained in the container. The drum is rotated at high speed, and the gas sucked out through the small holes becomes fine, uniformly sized microbubbles and disperses in the water, and the microbubbles are used to remove dust.
There are some that make the drum collide with the liquid surface at high speed.

However, in the above case, since there is a large moving part called the rotating drum, maintenance is required accordingly, and a large amount of power is required, so there is a problem of high running costs, especially in the case of a horizontal drum. However, there is also the problem of liquid leakage at the part where the rotating shaft of the drum penetrates the partition wall of the container, and the sealing part is complicated.

Furthermore, in the above-mentioned gas dispersion type gas-liquid contact device, it is difficult to control the dust removal rate, and such consideration is not taken. Furthermore, the method in which the drum collides with the liquid surface at high speed has the disadvantage that dust removal efficiency is low.

[Problem to be solved by the invention]

The present invention was made in order to solve the above-mentioned conventional problems, and it is possible to remove soot and dust from gas with a high dust removal rate, facilitate maintenance, and improve the dust removal rate. The object of the present invention is to provide a gas dust removal device that can control the

[Means for solving the problem] Gas dust removal in which a liquid is supplied simultaneously with the gas to be removed into a gas blowing pipe for the gas to be removed, and the liquid is blown out as a spray stream into the liquid whose ion concentration has been adjusted. The apparatus used to carry out this method consists of placing a liquid such as water in a container, placing an open end of a gas blowing pipe for the dust gas to be removed in the liquid, and connecting the open end with the inside of the container. The distance from the liquid surface, that is, the height at which gas is blown into the liquid, can be adjusted freely, and a gas outlet is provided above the liquid surface to blow gas containing dust into the liquid. As a result, fine bubbles are generated, and the gas is removed by diffusion and inertial collision within the bubble layer.

〔Example〕

The present invention will be described in detail below with reference to the drawings. FIG. 1 is an explanatory longitudinal cross-sectional view of a gas dust removal device in one embodiment of the present invention.

First, the device of this embodiment is for removing dust from the exhaust gas GK containing dust discharged from a coal boiler, etc. Dust is removed by passing Gw through a liquid, ie, water W, contained in a container 2 which is a dust remover, and a gas outlet 3 for the removed gas G is provided in the upper part of the container 2.

Next, a plurality of gas blow-off pipes 4 are provided that extend vertically below the passage 12 that communicates with the gas population 1, and the end portion 4A of the gas blow-off pipe 4 is opened into the water W in the container 2. It is set up.

In the above device, the distance H1 between the end 4A of the gas blow-off pipe 4 opened into the water W and the water surface W, L in the container 2, that is, the height of the exhaust gas Gw blown from the gas blow-off pipe 4 is controlled. That's what I do. Specifically, this can be done, for example, by adjusting the height of the water surface.

That is, in this embodiment, the water surface W and L height of the water W in the container 2 can be adjusted freely by the suction and drainage device 6 connected to the lower part of the container 2 via the pump 5.

In the dust removal device of this embodiment having the above configuration, the exhaust gas Gw containing fine dust is blown into water W from a number of gas blowing pipes 4 having open ends 4A at a flow rate of 10 to 50 m/sec, for example. By blowing into the air, fine bubbles of about 2 to 5 mm are generated, and a bubble layer 7 having a depth of, for example, about 200 to 1000 IIIa1 is generated.

As a result, the exhaust gas G- containing dust is removed by diffusion and inertial collision within this bubble layer 7, and in this case, it is possible to maintain a high dust removal rate even for submicrons of 1μ or less. Confirmed.

In addition, the blowing height of the above exhaust gas G-, that is, the water surface W,
The distance H between L and the end 4A of the gas blowing pipe 4 that opens into the water W is adjusted depending on the concentration and particle size of dust in the exhaust gas Gw, and the distance (am) H and the dust removal rate (%) is as shown in Figure 2.

In this case, the dust concentration of the gas G is automatically controlled by continuously measuring the dust concentration of the exhaust gas G to be removed and the gas G after dust removal, and cascading the data to the controller that controls the distance H. You can also.

In addition, the flow rate 700 of the exhaust gas Gw in the embodiment shown in FIG.
,000 BoN/hour, exhaust gas temperature 90°C, dust concentration at the inlet of 500 ■/n (N), and it has been confirmed that the dust concentration contained in gas G after dust removal is less than 5 ■/n (N). ,
In this case, the distance H is adjusted to about 130 mm, which is adjustable in the range of 0 to 500 mm.

In addition, in FIG. 1, a cooling nozzle 9 via a gas cooling pump 8 is provided in the gas population 1 of the exhaust gas G-, a stirrer 10 is provided in the container 1, and a gas outlet 3 from the gas collecting pipe 3A is provided. A mist eliminator 11 is disposed at.

Note that the means for adjusting the distance H described above is not limited to the pump 5 and the suction/drainage device 6 as in this embodiment; for example, adjusting the position of the gas blowing pipe 4 up or down, Means such as making the tube 4 telescopic may also be used.

In addition, if the gas to be removed and the liquid are simultaneously supplied into the gas blowing pipe of the gas to be removed into a liquid whose ion concentration has been controlled to change the surface tension of the liquid surface, and the gas to be removed and the liquid are blown out in the form of a spray stream,
It was possible to change the bubble diameter, and as a result, it was possible to improve the dust removal effect.

〔Effect of the invention〕

According to the gas dust removal method and apparatus of the present invention described above, dust is removed from exhaust gas containing fine dust at a high dust removal rate, and moreover, the dust removal rate is equal to the opening end of the gas blowing pipe. It has the advantage that it can be easily controlled by adjusting the distance to the liquid level.

In particular, in the device of the present invention, since the gas blow-off pipe portion is not rotated, power consumption is reduced, and there is no need for a sealing structure for the rotating bearing portion, making maintenance easy. Furthermore, by changing the surface tension of the liquid surface, the bubble diameter can be changed, and by controlling the change, the dust removal effect can be improved.

[Brief explanation of drawings]

FIG. 1 is an explanatory vertical cross-sectional view of a gas dust removal device according to an embodiment of the present invention, and FIG. 2 is a diagram showing the relationship between the blowing height of exhaust gas and the dust removal rate during dust removal by the device of FIG. 1. It is. 1... Gas inlet, 2... Container, 3... Gas outlet,
4... Gas blow-off pipe, 4A... Opening end of gas blow-off pipe, 6... Suction/drainage device, H... Distance, W, L... Water surface.

Claims (1)

[Claims] 1. A method for removing dust from a gas, in which a liquid is supplied simultaneously with the gas to be removed into a gas blowing pipe for the gas to be removed, and the liquid is blown out as a spray stream into the liquid whose ion concentration has been adjusted. . 2. The end of the gas blowing pipe for the gas to be removed is opened in the liquid in the container, and the distance between the open end and the liquid level in the container is adjustable, and the distance above the liquid level is adjusted. A gas dust removal device equipped with a gas outlet.