JP2002102649A - Gas treatment method and apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas treatment method and apparatus whereby a harmful gas, such as one exhausted from a process, etc., can be treated almost without the necessity for motive power and the treatment efficiency can be enhanced while the use of a treatment liquid is kept minimum. SOLUTION: A gas to be treated is caused to pass through permeable block- shaped porous bodies containing a gas absorption liquid or reaction liquid. Air passages may be set up in the block-shaped porous bodies themselves, and the porous bodies having affinity for the gas absorption liquid or reaction liquid area used. A new gas absorption liquid or reaction liquid is supplied to the porous bodies from the exhaust side of the gas to be treated, and the used gas absorption liquid or reaction liquid is discharged from the gas introduction side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for treating a desired gas, for example, a gas for absorbing or decomposing and absorbing a harmful gas discharged from a process with a liquid having a dissolving or decomposing action. The present invention relates to a processing method and a gas processing device.

[0002]

2. Description of the Related Art Conventionally, a desired gas is dissolved in a processing solution,
Alternatively, in order to perform processing such as dissolving after reacting with the liquid, for example, using a packed tower packed with cylindrical packing called Raschig ring, spraying the processing liquid from the upper part with a spray nozzle or the like, and from the lower part Scrubbers for introducing a gas to be treated are often used. Alternatively, gas is absorbed by inserting a porous material such as a diffuser tube into a tank containing the processing liquid, sending gas with a pump, etc., decomposing into fine bubbles through the porous material, and passing through the liquid area, called bubbling. There are also known methods for causing them to do so.

[0003] In addition, there is a device called an ejector (jet scrubber) for sucking a gas by a fast flow of a liquid sent by a pump and for strongly stirring the same, and a device for forcibly stirring by pumps. Each of these various methods and apparatuses has advantages and disadvantages, and those suitable for the intended processing conditions are employed.

[0004]

However, in the case of these prior arts, the following points cannot be avoided. First, when a packed tower or an ejector is used, a large amount of liquid is sprayed or pumped by a pump, so that a large amount of power is required. In addition, when a packed tower or a diffuser is used, power for feeding the gas to be treated is required, and when forcible stirring is performed by pumps, power for stirring is required.

[0005] Further, both of the above-mentioned prior arts have a problem that the processing solution is wasted. For example, in the case of a packed tower, since the liquid sprayed in the tower falls at a certain speed, the supply of a new liquid must always be continued to compensate for the drop. Also,
Even in the case of an ejector, it is necessary to feed a large amount of liquid in order to always ensure a certain suction capacity. There is also a method of circulating the solution to save the processing solution.However, the gas absorbed in the solution generally re-evaporates as the concentration in the solution increases, which may result in a reduction in the processing efficiency. is there.

In the method using an air diffuser, waste can be suppressed by reducing the amount of liquid supplied, but there is a problem that the re-evaporation lowers the processing efficiency as in the case of the circulation. On the other hand, for example, if the number of tanks is two or more, a decrease in processing efficiency due to re-evaporation can be suppressed, but in this case, the equipment becomes large and the cost is unavoidable.

[0007] In view of the above problems, the present invention requires almost no power when treating harmful gas discharged from a process or the like, and minimizes the use of a processing solution. It is an object of the present invention to provide a gas processing method and a gas processing device capable of improving efficiency.

[0008]

According to the present invention, there is provided a gas absorbing or reacting liquid, comprising:
A gas processing method is provided in which a gas to be processed is passed through a block-shaped porous body having air permeability. As described above, if a porous porous body such as a sponge containing a processing liquid such as a gas absorbing liquid or a reaction liquid is used, the porous body can be covered with almost no power. The processing gas can be passed, and the harmful components in the processing gas that has passed through the porous body can be absorbed or decomposed very efficiently.

Further, according to the present invention, the gas to be treated is supplied from one port to the other port of a container containing a plurality of gas-permeable block-shaped porous bodies containing a gas absorbing liquid or a reaction liquid. There is also provided a gas treatment method characterized by passing through. If a plurality of porous blocks in the form of a block having the above-mentioned permeability are packed in a container such as a packed tower, gas can easily pass between the porous bodies with weak wind power, and most of the power is used. There is no need.

Further, an air passage can be provided in the block-shaped porous body itself. By providing a ventilation path by opening a through-hole or the like in the block-shaped porous body itself, it is possible to reduce ventilation resistance,
Gas processing can be performed more efficiently.

As a further preferable method, a new liquid of the gas absorbing liquid or the reaction liquid is supplied to the block-shaped porous body from the exhaust side of the gas to be treated, and the treated liquid is discharged from the gas introducing side. (Claim 4). When the new processing liquid is supplied to the porous body in a direction opposite to the flow of the gas to be processed, the new processing liquid gradually absorbs the gas while moving through the porous body, and the discharged liquid has a high flow rate. Since the gas of the concentration is dissolved, it is very efficient, and the gas treatment can be continuously performed with the minimum necessary liquid amount.

Further, as the block-shaped porous body,
It is preferable to use one having an affinity for the gas absorbing solution or reaction solution used (claim 5). By using a block-shaped porous body having an affinity for the processing solution, it can be held in the porous body until the processing solution absorbs gas sufficiently, and a small amount of the processing solution can be used more efficiently. Gas treatment can be performed.

Further, according to the present invention, there is provided a gas processing apparatus for performing the gas processing method. That is, according to the present invention, the apparatus is filled with a filler, and a gas absorbing liquid or a reaction liquid is supplied to the filler, and the gas to be treated introduced from the gas inlet is passed through the filler. In a gas processing apparatus for exhausting gas from a gas exhaust port, there is provided a gas processing apparatus characterized in that the filler contains a gas absorbing liquid or a reaction liquid, and is a block-shaped porous body having air permeability. (Claim 6).

Preferably, an air passage is provided in the block-shaped porous body itself (claim 7), and the block-shaped porous body has an affinity for a gas absorbing liquid or a reaction liquid to be used. (Claim 8). If such a gas processing apparatus is used, gas processing can be performed very efficiently with a small amount of processing liquid.

[0015]

Embodiments of the present invention will be specifically described below with reference to the drawings, but the present invention is not limited to these embodiments. FIG. 1 is a diagram for explaining the concept of the present invention. The porous body 1 is not particularly limited as long as it can contain a gas absorbing liquid or a reaction liquid (treatment liquid) and has air permeability, but it is well compatible with the treatment liquid, has high retention, and has a high pressure and the like. It is preferable that the treatment liquid is kept in a state where the treatment liquid is kept unless a special forcing force is applied. For example, porous alumina and activated carbon can be used, and sponge is particularly preferable from the viewpoint of water absorption and air permeability. In addition,
The material is polyethylene, polyvinyl alcohol,
A hydrophilic sponge composed of vinyl chloride or the like is particularly advantageous.

As a gas treatment method using a porous body as described above, for example, a sponge is made to sufficiently contain a treatment liquid such as water, and the surface of the porous body containing the treatment liquid is used as a gas-liquid contact surface. Pass the processing gas through. At this time, a large gas-liquid contact area is secured in the porous body containing the processing liquid, and the porous body has air permeability, so that the gas to be processed can easily pass therethrough.

The method of including the treatment liquid in the porous body is not particularly limited, but the porous body may be immersed in the treatment liquid,
A treatment liquid may be applied to the porous body. In addition, the porous body only needs to contain the treatment liquid, and the containing mode is as follows.
Any type such as absorption, adsorption, adhesion, and penetration may be used.

Since the processing liquid is sufficiently impregnated into the porous material, the gas-liquid interface is as complicated and rough as the pore distribution of the porous material, and as a result, a large number of air bubbles are dispersed in the liquid. Is making a state. Therefore, according to the gas processing method of the present invention, high efficiency gas-liquid contact processing is possible by supplying only the required amount of the processing liquid, requiring almost no power for feeding the gas to be processed and the processing liquid. Becomes Note that the gas absorbing liquid and the processing liquid of the reaction liquid may be appropriately selected according to the type, physical properties, and reactivity of the gas to be processed, and water or an aqueous alkaline solution can be suitably used.

In the present invention, since a block-shaped porous body having good air permeability is used, the gas to be treated exhausted from a process or the like can be used as it is without using a special power such as a blower. However, the porous body 1 'itself can be provided with an appropriate ventilation path 2 as shown in FIG. 2 to further reduce the ventilation resistance. In this case, if the hole diameter of the ventilation path 2 is too large or the number of the ventilation paths 2 is too large, gas-liquid contact may be insufficient and the absorption rate of the gas to be treated may decrease. Is appropriately selected, the process proceeds and is agitated until the gas to be processed exits from the inlet to the outlet of the ventilation path 2, so that there is no problem.

As a method of reducing the airflow resistance, the air permeability can be improved by providing the air passage in the porous body itself as described above, or by filling a plurality of the porous bodies.
As a specific method, a block-shaped porous body containing a gas absorbing liquid or a reaction liquid, and having a suitable size having gas permeability is filled in a plurality of containers such as a tube or a tower, and one of the containers is filled. The gas to be processed can be made to pass from one port to the other port.

In the case of intermittent, short-term gas treatment, the gas to be treated is passed through an appropriately sized block-shaped porous body containing a gas absorbing solution or a reaction solution and having air permeability as described above. This allows the gas to be sufficiently processed. For example, if a sponge is used as a porous body and the gas absorbing liquid contained in the sponge absorbs gas sufficiently and saturates, the sponge is squeezed and then a new absorbing liquid is included to repeatedly perform gas treatment. It can be carried out.

In the case of continuous and long-term gas processing, it is necessary to continuously supply a processing liquid such as an absorbing liquid to the porous body. In this case, a new liquid of the gas absorbing liquid or the reaction liquid is
It is preferable that a small amount of the gas to be treated is supplied from the exhaust side, and the treated liquid is discharged from the gas introduction side using only gravity as power.

FIG. 3 shows a gas processing apparatus 20a according to the present invention, in which perforated plates 4a and 4b are arranged at upper and lower portions in a cylindrical vessel (packing tower) 3a, and plates 4a and 4b are provided.
A porous body 1a such as a sponge is filled between them. Tower 3
The gas to be treated introduced from the gas inlet 10 near the bottom of a passes through the porous body 1a and is exhausted from the gas outlet 11 at the upper end of the tower 3a. On the other hand, the processing liquid of the gas absorbing liquid or the reaction liquid is dropped from the processing liquid tank 5 to the porous body 1a from above the packed tower 3a through the supply pipe 7 by the pump 6.

Exhaust side of gas to be treated (gas exhaust port 11 side)
The new liquid such as the gas absorbing liquid dropped on the porous body 1a from
It penetrates the porous body 1a and is held to a certain amount. When the processing liquid in the porous body 1a exceeds a certain amount, the processing liquid falls from the porous body 1a by gravity and is discharged. As shown in FIG. 3, when the new liquid is supplied from the exhaust side of the gas to be processed, the new processing liquid flows through the porous body on the gas introduction side (the gas introduction port 10).
Side) gradually absorbs gas while moving. Therefore, the gas concentration in the processing liquid moving through the porous body 1a becomes higher as it approaches the gas introduction side, and reaches the lower plate 4b when the processing (absorption) capacity is reduced most. The treatment liquid that has sufficiently absorbed the gas falls and is stored in the waste liquid tank 9a through the absorption liquid discharge pipe 8a at the lower end of the packed tower 20a.

If the supply rate of the new solution is too low, the concentration in all the processing solutions may be saturated and the gas may be exhausted without being sufficiently absorbed. On the other hand, if the supply speed is too high, the processing liquid is discharged without absorbing the gas sufficiently, and is wasted. Therefore, the supply rate of the new liquid is such that the concentration of the desired component in the gas exhausted through the porous body 1a is sufficiently low and the gas concentration in the processing liquid discharged from the porous body 1a is sufficiently high. It may be appropriately set according to the concentration of the gas to be treated and the flow velocity conditions so that the concentration becomes as close as possible to the saturation concentration.

By supplying the processing liquid as described above, the state in which the liquid to be processed is old on the introduction side and the liquid on the exhaust side is kept fresh, and only the processing liquid that has sufficiently absorbed the gas is discharged. Will be done. As a result, the gas does not re-evaporate from the processing liquid that has absorbed the gas as in various conventional wet scrubbers, so that the processing efficiency does not decrease, and higher processing efficiency is maintained. In the gas processing device shown in FIG.
Since the amount of the processing liquid supplied to the porous body 1a may be small,
The power for operating the pump 6 is extremely small. Alternatively, by installing the processing liquid tank 5 above the packed tower 3a,
The processing liquid can be supplied without using the pump 6.

When it is not necessary to continuously process the gas, it is not necessary to provide a supply pipe or the like for supplying the processing liquid. In this case, the porous body preliminarily containing the processing liquid is filled in the tower. do it. Furthermore, in the present invention, there is no need to circulate the processing liquid, and it is not necessary to provide power or equipment for the processing liquid. Therefore, the apparatus becomes extremely simple and inexpensive, and there is no problem of re-evaporation.

FIG. 4 shows another gas processing apparatus according to the present invention. The apparatus 20b shown in the figure is similar to the gas processing apparatus 20a shown in FIG. 3 in that a porous porous body 1b having air permeability is filled between upper and lower plates 4a and 4b of a cylindrical container (packing tower) 3b. In addition, for example, a treatment liquid such as tap water is sprayed from above the packed tower 20b through the spray nozzle 12, and the treatment liquid is supplied to the porous body 1b. The gas to be treated introduced from the gas inlet 10 passes through the porous body 1b containing the gas absorbing liquid, and is exhausted from the gas exhaust port 11 at the upper end of the tower 20b. The processing solution that has reached the lower plate 4b while absorbing the gas falls and falls into the tower 2b.
0b is accommodated in a waste liquid tank 9b provided at the lower end,
It is discharged through the discharge pipe 8b.

As described above, according to the present invention, in order to allow the gas to be processed to pass through the block-shaped porous body containing the gas absorbing liquid or the reaction liquid and having air permeability, the gas and the processing liquid are supplied. The power can be hardly required, and the gas can be absorbed in the processing liquid without waste. Therefore, it is possible to achieve a very high processing efficiency with a much smaller amount of liquid compared to a conventional gas processing apparatus such as a scrubber that sprays the absorbing liquid into a packed tower filled with Raschig rings, There is no waste. Further, since there is no need to provide multiple stages to achieve high efficiency unlike the conventional wet scrubber, gas processing can be performed at low cost and with high efficiency.

[0030]

EXAMPLES Example 1 A hydrophilic sponge sheet made of polyethylene (diameter 3 cm × thickness 3 c) was placed in a cylinder having an inner diameter of 3 cm.
m) was placed therein, water was contained therein, and air containing 10 ppm of hydrogen chloride was passed from one of the ports (gas introduction side) at a linear velocity of 2 cm / sec. When the hydrogen chloride concentration was measured at the other port (gas exhaust side) of the sponge sheet,
pm.

Example 2 About 1000 pieces of 4 mm-diameter through-holes (air passages) were opened in parallel in 30 cm 3 porous alumina so as to disperse them almost evenly. After arranging the porous alumina in the tube, 1% caustic soda is contained, and chlorine gas is supplied to the air from one side (gas introduction side) to the opposite side (gas exhaust side) in the same direction as the ventilation path. 100p
The gas containing pm was flowed at 100 L / min. At this time, when the chlorine gas concentration on the gas exhaust side was measured with a detector tube, it was below the detection limit (0.5 ppm or less).

(Example 3) A 10 mm thick foamed vinyl chloride sheet (manufactured by Takaramachi Chemical Co., Ltd.) was cut, and each side was 10 m in length.
Approximately 27000 cubes of m were filled in a cylinder having a diameter of 300 mm. As shown in FIG. 3, an alkaline solution was dropped from above the filler (a cube of foamed vinyl chloride). Alkaline solution is 35% monoethanolamine aqueous solution, dropping speed is 3m
1 / min. When the foamed polyvinyl chloride of the filling material has sufficiently absorbed the alkaline liquid and the liquid has gradually accumulated in the waste liquid tank 9a, 1000 p.
Nitrogen gas containing chlorine gas of pm was continuously flown at a passing speed of 100 L / min for one month. During that time, the chlorine concentration in the exhaust gas was continuously monitored at the gas exhaust port 11, but always showed 0 ppm (detection limit 0.5 ppm or less).

Example 4 Water was supplied at a rate of 200 ml / min from a top of a 300 mm diameter cylinder filled with 20 kg of a columnar activated carbon having a diameter of 5 mm and a height of 3 mm by a spray nozzle 12 as shown in FIG. Sprayed. Activated carbon was hydrophilic, and began to fall downward after exceeding the permissible value after being sufficiently impregnated with water. After this, 5 ppm of HF was added to the air.
The contained gas was passed upward from below the cylinder 3b.
Although the treatment was continuously performed for 30 days, the HF concentration in the gas at the exhaust port 11 was always 0 ppm (detection limit 1 ppm).
Was shown.

The present invention is not limited to the above embodiment. The above embodiment is merely an example, and has substantially the same configuration as the technical idea described in the claims of the present invention, and has the same function and effect,
Anything is included in the technical scope of the present invention.

In the above embodiment, the case where gas treatment is performed by filling a porous body in a cylindrical container has been mainly described.
The shape of the container is not limited to a cylindrical shape. For example, a horizontally long container may be filled with a porous material, and a gas treatment may be performed by supplying a processing liquid such as an absorbing liquid not only in a vertical direction but also in a horizontal direction or a direction inclined thereto. Can also. Further, the gas to be treated is not limited to the harmful gas discharged from the process, and can be applied to any field for the purpose of absorbing a gas into a liquid.

[0036]

According to the present invention, the gas to be treated is passed while the gas-liquid contact area is kept large by using a gas-permeable block-shaped porous body containing a gas absorbing liquid or a reaction liquid. Gas processing can be performed very efficiently. Since the processing liquid such as the gas absorbing liquid is held in the porous body, the gas can be dissolved at a high concentration in a small amount of the processing liquid, and the processing liquid is not wasted.

Further, a new liquid of the gas absorbing liquid or the reaction liquid is supplied to the block-shaped porous body from the exhaust side of the gas to be treated, and the treated liquid is discharged from the gas introduction side, thereby to be treated. The state that the liquid on the gas introduction side is old and the liquid on the exhaust side is new is continuously maintained. As a result, the gas does not re-evaporate from the processing liquid that has absorbed the gas as in various conventional wet scrubbers, so that the processing efficiency does not decrease, and higher processing efficiency is maintained. Therefore, it is not necessary to provide multiple stages in order to achieve high efficiency, and equipment costs can be reduced.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining the concept of the present invention.

FIG. 2 is a schematic view showing a block-shaped porous body used in the present invention in which an air passage is provided in the porous body itself.

FIG. 3 is a schematic diagram showing one configuration example of a gas processing device according to the present invention.

FIG. 4 is a schematic diagram showing another configuration example of the gas processing apparatus according to the present invention.

[Explanation of symbols]

1, 1 ', 1a, 1b: porous body, 2: air passage, 3
a, 3b: cylindrical container (packed tower), 4a, 4b: perforated plate, 5: treatment liquid tank, 6: pump, 7: supply pipe, 8a, 8b: discharge pipe, 9a, 9b: waste liquid tank, 10: gas Inlet, 11 Gas outlet, 12
... Spray nozzles, 20a, 20b ... Gas treatment devices.

Claims (8)

[Claims] 1. A gas processing method comprising passing a gas to be processed through a block-shaped porous body containing a gas absorbing liquid or a reaction liquid and having air permeability. 2. A container containing a gas absorbing liquid or a reaction liquid and filled with a plurality of block-shaped porous bodies having gas permeability, wherein the gas to be treated is passed from one port to the other port. Gas treatment method. 3. The gas processing method according to claim 1, wherein a ventilation path is provided in the block-shaped porous body itself. 4. A new liquid of the gas absorbing liquid or the reaction liquid,
The gas treatment according to any one of claims 1 to 3, wherein the gas to be treated is supplied to the block-shaped porous body from the exhaust side, and the treated liquid is discharged from the gas introduction side. Method. 5. The block-shaped porous body according to claim 1, wherein the porous body has an affinity for a gas absorbing solution or a reaction solution to be used. The gas processing method according to the above. 6. An apparatus is filled with a filling material, a gas absorbing liquid or a reaction liquid is supplied to the filling material, and a gas to be treated introduced from a gas inlet is passed through the filling material. A gas processing apparatus for exhausting gas from an exhaust port, wherein the filling contains a gas absorbing liquid or a reaction liquid, and is a block-shaped porous body having air permeability. 7. The gas processing apparatus according to claim 6, wherein a ventilation path is provided in the block-shaped porous body itself. 8. The gas processing apparatus according to claim 6, wherein the block-shaped porous body has an affinity for a gas absorbing liquid or a reaction liquid to be used.