JPH0478412A - Gas absorption method - Google Patents

Abstract

PURPOSE:To enhance efficiency in absorbing the material in a waste gas by injecting a liq. most of which forms the droplets of the minimum size for the free falling in the waste gas current into the waste gas flowing from the lower part to the upper part. CONSTITUTION:The waste gas 11 is introduced into an absorption tower 1 from an inlet 9 and allowed to ascend in the tower 1, a liq. 6 stored in the lower part 5 of the tower 1 is sent to a spraying device 2 through a pipeline 7 by a spray pump 4, injected from a nozzle 3 and atomized to form a droplet 14 of the minimum diameter capable of free-falling against the flow of the waste gas 11, the SO2, dust, etc., in the waste gas 11 are absorbed by the droplets, and the droplets are free-falling to the lower part 5 of the tower 1 against the flow of the waste gas 11. The mist in the waste gas 11 freed of SO2, dust, etc., is removed by an eliminator 8, and the waste gas is discharged to the outside of the tower 1 from an outlet 10. Since the droplet 14 is free- falling, the eliminator 8 is not overloaded, and the mist in the waste gas 11 is surely removed.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a gas absorption method.

[Prior Art] Wet gas absorption methods have conventionally been used to remove various substances such as SO3 and soot contained in boiler exhaust gas.

An example of a device applied to such a gas absorption method will be explained with reference to FIG. 4. In the figure, a is an absorption tower, and b is installed in multiple stages within the absorption tower a, and each stage is provided with a plurality of nozzles C. d is a spray pump that supplies a liquid f such as water stored in the lower part e of the absorption tower a to each of the spray devices through a pipe g, and h is a spray pump that passes through the uppermost spray device. eliminator that removes mist from the flue gas k, i is the flue gas inlet provided on the side of the middle part of the absorption tower a, and j
1 is the exhaust gas outlet provided at the top of the absorption tower a, and 1 is the droplet formed by the liquid f being injected from the nozzle C of the spray device.

In the above device, the exhaust gas is introduced into the absorption tower a from the exhaust gas population i and rises within the absorption tower a.

On the other hand, the liquid f stored in the lower part e of the absorption tower a is sent to the spray device @b via the pipe g by the spray pump d, and is injected downward from the nozzle C to form droplets 1. Substances such as SO2 and soot in the exhaust gas are absorbed by the droplets L, and the droplets L that have absorbed the substances are transported to the lower part e of the absorption tower a.
to fall.

Further, the exhaust gas from which substances such as soot and soot have been removed has its mist removed by an eliminator h, and is discharged to the outside of the absorption tower a from an exhaust gas outlet j.

[Problems to be Solved by the Invention] In the above-mentioned gas absorption method, the diameter of the droplet 1 formed by dividing the liquid f injected from the nozzle C (droplet diameter ) is 2000 to 3000 μm empirically.
The size of nozzle C was selected so that the droplet diameter was relatively large, so the specific surface area that contributes to absorption (the ratio of the droplet surface area determined from the flow rate of liquid f and the droplet diameter)
Therefore, in order to obtain high absorption efficiency, a large amount of liquid f must be injected from nozzle C per unit time, which increases the size of the device and increases equipment costs and operation and maintenance costs. There is a problem that there is a limit to the efficiency that can be achieved even if the flow rate of the liquid f is increased.

The present invention has been made in view of the above-mentioned circumstances with the aim of improving the absorption efficiency of substances in exhaust gas and reducing equipment costs and operation and maintenance costs.

[Means for Solving the Problems] The invention of claim 1 provides that the exhaust gas flowing from below to above,
The invention as claimed in claim 2 is a method for injecting a liquid so as to form the smallest droplets that are large enough to fall freely with respect to the flow of exhaust gas, and for the droplets to absorb substances in the exhaust gas. The liquid is injected into the exhaust gas flowing upward from the exhaust gas flow so that the droplets contain droplets of a size that does not fall freely against the flow of the exhaust gas, and the droplets containing the droplets that do not fall freely against the flow of the exhaust gas A liquid is ejected so as to absorb the substances inside and form droplets of a size that freely fall against the flow of exhaust gas, and the droplets of a size that does not fall freely are collected by the droplets of a size that freely fall. It is something that makes you

[Function] In the invention of claim 1, the liquid is injected into the exhaust gas flowing from the bottom to the top so that most of the liquid drops freely with respect to the flow of the exhaust gas and becomes the smallest droplet. The droplets absorb substances in the exhaust gas.

Further, in the invention of claim 2, the liquid is injected so that the exhaust gas flowing from the bottom to the top contains droplets of a size that does not fall freely with respect to the flow of the exhaust gas, and Substances in the exhaust gas are absorbed by droplets containing droplets of Droplets that are too large to fall are collected.

[Embodiments] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

FIG. 1 shows an embodiment of the apparatus applied to the method of the present invention, in which 1 is an absorption tower, and 2 is a sprayer installed in multiple stages within the absorption tower 1, with a plurality of nozzles 3 provided in each stage. device, 4
8 is a spray pump that supplies a liquid 6 such as water stored in the lower part 5 of the absorption tower 1 to each spray device ft2 through a pipe 7, and 8 is a mist from the exhaust gas 11 that has passed through the uppermost spray device f2. an eliminator for removing the
The exhaust gas outlet 14 provided at the top of the spray device 2 is a droplet formed by the liquid 6 being injected from the nozzle 3 of the spray device 2 .

Furthermore, the diameter (droplet diameter) of the droplet 14 formed by the finer liquid 6 injected from the nozzle 3 is such that most of the droplet 14 resists the flow of the exhaust gas 11 flowing from the bottom to the top. The nozzle 3 is selected so that it has the smallest droplet diameter that allows it to fall freely.

Specifically, when the flow rate of the exhaust gas 11 is 3 to 4 m/sec, the nozzle 3 is selected so that the droplet diameter is about 500 to 1000 μm.

Furthermore, the nozzles 3 have been selected to produce smaller droplets than conventional ones, making them more compact.As a result, the distance between adjacent nozzles 3.3 and the height H between the upper and lower spray devices 2, 2 can be reduced. It is smaller, and the number of stages of the spray device W2 can be smaller than that of the conventional device.

Next, to explain the operation of the above embodiment, the exhaust gas 11
is introduced into the absorption tower 1 from the exhaust gas population 9 and rises inside the absorption tower 1, while the liquid 6 stored in the lower part 5 of the absorption tower 1 is sent to each spray via the pipe 7 by the spray pump 4. The droplets are sent to the device 2 and sprayed downward from the nozzle 3 to become fine droplets 14 that have the smallest diameter that can freely fall against the flow of the exhaust gas 11, absorbing substances such as SO3 and soot dust in the exhaust gas 11. , absorption tower 1 against the flow of exhaust gas 11
falls freely to the bottom 5 of

Furthermore, the exhaust gas 11 from which substances such as SO8 and soot have been removed has its mist removed by the eliminator 8, and is discharged to the outside of the absorption tower 1 from the exhaust gas outlet 10.

As mentioned above, the diameter of the droplet 14 formed by being injected from the nozzle 3 is set to the minimum diameter that allows it to fall freely against the flow of the exhaust gas 11, so the specific surface area of the droplet 14 increases and the exhaust gas The eliminator 8 can efficiently absorb substances such as SO8 and soot dust in the exhaust gas 11, and the eliminator 8 will not be overloaded due to free falling of the droplets 14, so the mist in the exhaust gas 11 can be removed reliably. It can be carried out.

Also, if the flow rate of the exhaust gas 11 is the same as that of the conventional one, the amount of liquid 6 injected from the nozzle 3 per unit time will be small, so the spray pump 4 can be small, and the driving power of the spray pump 4 can also be reduced. Less is better.

Droplet diameter and SO! An example of the absorption efficiency relationship is shown in Figure 2, and when the droplet diameter exceeds 1000 μm, the S02 absorption efficiency η
It can be seen that the value decreases rapidly. Note that the SO2 absorption efficiency η is expressed as −B η=X 100 , where the concentration of Sow at the exhaust gas population 9 is B and the concentration of SOI at the A1 exhaust gas outlet 10 is B.

FIG. 3 shows another embodiment of the apparatus applied to the method of the present invention,
The difference from the previous embodiment is that the nozzle 3 is selected so that the droplets 14 ejected from the nozzle 3 include droplets of a size that does not fall freely against the flow of the exhaust gas 11, and Above the spray equipment RA2, another nozzle 1
Spray equipment with 3! 12 is provided so that the liquid 6 injected from the nozzle 13 becomes droplets 15 of a size sufficient to freely fall against the flow velocity of the exhaust gas 11.

By providing such a spray device 12, the droplets 14 ejected from the spray device 2 can be made smaller in diameter, and the absorption efficiency of substances such as SO2 and soot is further improved. The droplets 14 in the exhaust gas 11 that have passed through the uppermost spray device 2 and have a diameter that does not fall freely are collected by droplets 15 that are sprayed from the nozzle 13 of the spray device 112 and have a diameter that can fall freely. As a result, the amount of droplets 14 that are accompanied by the exhaust gas 11 and reach the eliminator 8 is reduced, and as a result, the eliminator 8 is prevented from being overloaded, and as a result, the mist removal efficiency is improved. improves.

In addition, in the embodiment of the present invention, the diameter of the droplet jetted from the nozzle that jets the substance absorption liquid is specifically 5.
Although the case where the droplet diameter is 00 to 1000 μm has been described, it is possible to select various droplet diameters depending on the flow rate in the exhaust gas absorption tower, and various other changes can be made without departing from the gist of the present invention. Of course, etc.

[Effects of the Invention] According to the gas absorption method of the present invention, the specific surface area of the droplets increases in both cases, so the substance absorption efficiency improves, and the amount of liquid per unit time can be small, making the device can be miniaturized, equipment costs and operation and maintenance costs are low, and even if droplets of a size that will not freely fall are included, droplets of a size that will not freely fall can be collected by droplets of a size that will not freely fall. As a result, various excellent effects such as the ability to reliably remove mist can be obtained.

[Brief explanation of the drawing]

FIG. 1 is an elevational view of an embodiment of the apparatus applied to the method of the present invention, and FIG. 2 shows droplet diameter and SOx in the embodiment of FIG. 1.
A graph showing the relationship between absorption efficiency, FIG. 3 is an elevational view of another embodiment of the apparatus applied to the method of the present invention, and FIG. 4 is an elevational view of an example of the apparatus applied to the conventional method. In the figure, 6 indicates liquid, 11 indicates exhaust gas, and 14.15 indicates droplets.

Claims (1)

[Claims] 1) A liquid is injected into the exhaust gas flowing from the bottom to the top so that the majority of the liquid falls freely with respect to the flow of the exhaust gas and becomes the smallest droplet. A gas absorption method characterized by absorbing a substance. 2) A liquid is injected into the exhaust gas flowing from the bottom to the top so that it becomes a droplet that contains droplets of a size that does not fall freely against the flow of the exhaust gas, and a liquid that contains droplets of a size that does not fall freely against the flow of the exhaust gas. The liquid is jetted so that the droplets absorb substances in the exhaust gas and become droplets of a size that freely fall against the flow of the exhaust gas, and the droplets of a size that does not fall freely are replaced by the droplets of a size that does not fall freely. A gas absorption method characterized by collecting.