JP5612979B2 - Method and apparatus for purifying sulfur dioxide gas - Google Patents

Description

  The present invention relates to a method and apparatus for purifying sulfur dioxide gas.

  Sulfur dioxide gas is used in various applications such as food additives, raw materials for industrial chemicals, and raw materials for pharmaceuticals. Such sulfur dioxide gas is produced, for example, by burning crude sulfur to obtain a crude gas containing sulfur dioxide gas, and removing impurities from the crude gas (see, for example, Patent Document 1).

Among the uses of the sulfur dioxide gas, for example, as a food additive, high-purity sulfur dioxide gas not containing sulfur is required.
Therefore, as a method for purifying sulfur dioxide gas from sulfur dioxide-containing gas containing sulfur that is difficult to remove as impurities, for example, the sulfur dioxide-containing gas containing sulfur vapor is cooled to liquefy and remove the sulfur vapor. Thus, a method for purifying sulfur dioxide gas has been proposed (see, for example, Patent Document 2).

Japanese Patent Laid-Open No. 11-157811 Japanese Patent Publication No. 50-61399

  However, when sulfur is present in a sulfur dioxide-containing gas in a supersaturated state, the sulfur supersaturated state is stably maintained over a wide temperature range. It is difficult to sufficiently remove sulfur contained in the gas.

  The present invention has been made in view of such problems, and a sulfur dioxide gas purification method and purification capable of easily and efficiently producing a high-purity sulfur dioxide gas having a reduced sulfur content. An object is to provide an apparatus.

  In the method for purifying sulfur dioxide gas of the present invention, a sulfur dioxide-containing gas containing sulfur as an impurity is blown into a sulfuric acid solution having a temperature difference from the sulfur dioxide-containing gas, whereby the sulfur is contained in the sulfuric acid solution. It is characterized in that it is precipitated and removed to obtain sulfur dioxide gas.

  In the method for purifying sulfur dioxide gas of the present invention, since the sulfur dioxide-containing gas is blown into a sulfuric acid solution having a temperature difference from the sulfur dioxide-containing gas, sulfur is supersaturated in the sulfur dioxide-containing gas. Even if it exists in a state, the supersaturated state of the sulfur can be easily eliminated and sulfur can be precipitated in the sulfuric acid solution. Since the sulfur precipitate produced in this way can be easily removed from the sulfuric acid solution, according to the method for purifying sulfur dioxide gas of the present invention, high-purity sulfur dioxide with a reduced sulfur content is obtained. It can be manufactured easily and efficiently.

  In the method for purifying sulfur dioxide gas of the present invention, the concentration of sulfuric acid in the sulfuric acid solution is preferably 80 to 98.6% by mass. In this case, since the solvent of sulfuric acid in the sulfuric acid solution can be suppressed from being mixed into the sulfur dioxide gas, the content of the solvent can be reduced and a higher-purity sulfur dioxide gas can be obtained.

  Moreover, in the purification method of sulfur dioxide gas of this invention, it is preferable to refine | miniaturize the bubble of the sulfur dioxide containing gas formed in the sulfuric acid solution by stirring, blowing in a sulfur dioxide containing gas in a sulfuric acid solution. In this case, since the contact efficiency between the sulfuric acid solution and the sulfur dioxide-containing gas can be increased, it is possible to deposit and remove sulfur more efficiently. Therefore, according to the purification method employing such a configuration, it is possible to more efficiently obtain a high-purity sulfur dioxide gas with a reduced sulfur content.

  In the method for purifying sulfur dioxide gas of the present invention, the temperature difference is preferably at least 5 ° C. In this case, the balance of the supersaturated state of sulfur in the sulfur dioxide-containing gas is easily broken, and the elimination of the supersaturated state of sulfur can be promoted, so that it is possible to deposit and remove sulfur more efficiently. . Therefore, according to the purification method employing such a configuration, it is possible to more efficiently obtain a high-purity sulfur dioxide gas with a reduced sulfur content.

  The sulfur dioxide purification apparatus of the present invention is a sulfur dioxide gas purification apparatus for purifying sulfur dioxide gas from a sulfur dioxide-containing gas containing sulfur as an impurity, using the sulfur dioxide gas purification method described above. A sulfuric acid tank containing a sulfuric acid solution having a temperature difference with the sulfur-containing gas, and a sulfur dioxide-containing gas flow path for conveying the sulfur dioxide-containing gas to the sulfuric acid tank and blowing the sulfur dioxide-containing gas into the sulfuric acid solution It is characterized by having.

  According to the apparatus for purifying sulfur dioxide gas in which such a configuration is adopted, the sulfur dioxide-containing gas can be blown into a sulfuric acid solution having a temperature difference from the sulfur dioxide-containing gas. The same effects as the gas purification method can be obtained.

  In the sulfur dioxide gas purification apparatus of the present invention, the sulfuric acid solution regeneration flow path for regenerating the sulfuric acid solution by removing sulfur from the sulfuric acid solution containing sulfur deposits is regenerated downstream of the sulfuric acid tank. It is preferable to further include a sulfuric acid solution return passage for returning the sulfuric acid solution to the sulfuric acid tank. In this case, the used sulfuric acid solution can be reused. Thereby, it becomes possible to refine | purify the high purity sulfur dioxide gas with which sulfur content was reduced at low cost.

  In the sulfur dioxide gas purification apparatus of the present invention, the sulfuric acid tank is installed in the tank main body containing the sulfuric acid solution and in the tank main body, and is dispersed to blow bubbles of sulfur dioxide-containing gas into the sulfuric acid solution. It is preferable to include a trachea and a stirrer that is installed above the air diffuser in the tank body and agitates the sulfuric acid solution into which the bubbles are blown to refine the bubbles. Since the contact efficiency between the sulfuric acid solution and the sulfur dioxide-containing gas can be increased, sulfur can be precipitated and removed more efficiently. Therefore, according to the refiner | purifier by which this structure was employ | adopted, the highly purified sulfur dioxide gas with which sulfur content was reduced can be manufactured more efficiently.

  According to the method and apparatus for purifying sulfur dioxide gas of the present invention, high-purity sulfur dioxide gas having a reduced sulfur content can be produced easily and efficiently.

It is a block diagram which shows the principal part structure of the refiner | purifier of the sulfur dioxide gas which concerns on one Embodiment of this invention.

First, a sulfur dioxide gas purification device according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a block diagram showing a main configuration of a sulfur dioxide gas purifier according to an embodiment of the present invention.

A purification apparatus 1 shown in FIG. 1 includes a sulfur dioxide-containing gas flow path 10 that conveys a sulfur dioxide-containing gas containing sulfur as an impurity, and a sulfuric acid tank 20 that contains a sulfuric acid solution.
Further, the purifier 1 removes sulfur from the sulfuric acid solution containing the sulfur dioxide gas flow path 30 for conveying the refined sulfur dioxide gas to the outside of the purifier 1 and the sulfur precipitate on the downstream side of the sulfuric acid tank 20. Then, a sulfuric acid solution regeneration flow path 40 for regenerating the sulfuric acid solution and a sulfuric acid solution return flow path 50 for returning the regenerated sulfuric acid solution to the sulfuric acid tank 20 are provided.

The sulfur dioxide-containing gas flow path 10 is connected to the sulfuric acid tank 20 and supplies the sulfur dioxide-containing gas to the sulfuric acid tank 20.
The sulfuric acid tank 20 includes a tank main body 21 that stores a sulfuric acid solution, a tank main body 21 that stores a sulfuric acid solution, a diffuser tube 22 that blows bubbles of sulfur dioxide-containing gas into the sulfuric acid solution, and bubbles are blown into the sulfuric acid tank 20. And a stirrer 23 for agitating the sulfuric acid solution to refine the bubbles.
In the sulfuric acid tank 20, sulfur in the sulfur dioxide-containing gas blown into the sulfuric acid solution is precipitated in the sulfuric acid solution. And sulfur dioxide gas is refine | purified by removing the deposited sulfur.

The tank body 21 is a container having resistance to sulfuric acid.
The tank body 21 contains a sulfuric acid solution having a temperature difference with the sulfur dioxide-containing gas.

The air diffusion tube 22 includes a tube body 22b and a straight tubular nozzle 22a provided on the lower side of the tube body 22a. The air diffuser 22 is installed on the lower side in the tank body 21. In addition, one end side of the tube main body 22 b of the diffuser tube 22 is connected to the sulfur dioxide-containing gas flow path 10. Thereby, the sulfur dioxide containing gas conveyed by the sulfur dioxide containing gas flow path 10 is supplied to the sulfuric acid solution accommodated in the tank main body 21 through the straight tubular nozzle 22a of the diffusion tube 22. Yes.
The shape of the nozzle of the air diffusion tube 22 may be a ring shape, a porous shape, etc. in addition to a straight tube shape. From the viewpoint of preventing clogging of the nozzle holes due to the growth of precipitated sulfur crystals, the shape is preferably a straight tube.

  The stirrer 23 is installed above the diffuser tube 22 in the tank main body 21. The stirrer 23 has a plurality of stirring blades 23b radially attached to the tip of a rotating shaft 23a that is rotationally driven by a motor 23c. As a result, as shown in FIG. The bubbles B1 of the sulfur dioxide-containing gas supplied to the sulfuric acid solution through 22a can be refined by the shearing force generated by stirring by the stirring blade 23a, and bubbles B2 having a smaller diameter than the bubbles B1 can be generated. Therefore, the contact efficiency between the sulfur dioxide-containing gas and the sulfuric acid solution can be increased, and the elimination of the supersaturated state of sulfur can be promoted. Thereby, it becomes possible to deposit sulfur more efficiently.

The sulfuric acid tank 20 may have a temperature adjusting means for heating or cooling the sulfuric acid solution in the tank main body 21. Thereby, the temperature difference between sulfur dioxide containing gas and a sulfuric acid solution can be set easily.
The sulfur dioxide gas flow path 30 is connected to the downstream side of the sulfuric acid tank 20, and conveys the sulfur dioxide gas obtained in the sulfuric acid tank 20 (“purified sulfur dioxide gas” in the figure) to the outside of the purification apparatus 1. .

The sulfuric acid solution regeneration channel 40 is connected to the bottom of the sulfuric acid tank 20.
The sulfuric acid solution regeneration channel 40 includes a filter 41 that removes the sulfur by filtering the sulfuric acid solution containing the precipitated sulfur, and a storage tank 42 that stores the sulfuric acid solution after filtration.
A pump P <b> 1 is provided in the middle of the sulfuric acid solution flow path 40, and a sulfuric acid solution containing sulfur deposited from the sulfuric acid tank 20 is extracted and conveyed to the filter 41.
The filter 41 includes a filtration membrane that removes sulfur deposits in the sulfuric acid solution. The filtration method by the filter 41 is not particularly limited, and examples thereof include a vacuum filtration method, a pressure filtration method, and a centrifugal filtration method. Of these, the centrifugal filtration method is preferable from the viewpoint of ensuring high filtration efficiency.
The storage tank 42 is connected downstream of the filter 41 and stores the sulfuric acid solution from which sulfur has been removed by the filter 41.
The storage tank 42 is a container having resistance to the sulfuric acid solution.

One end of the sulfuric acid solution return flow path 50 is connected downstream of the storage tank 41 via the pump P <b> 2, and the other end is connected to the sulfuric acid tank 20.
The connection position of the sulfuric acid solution return flow path 50 with respect to the sulfuric acid tank 20 is located above the connection position of the sulfuric acid solution regeneration flow path 40. Thereby, the sulfuric acid solution containing the precipitate of sulfur in the sulfuric acid tank 20 and the regenerated sulfuric acid solution are easily exchanged.

Next, the method for purifying sulfur dioxide gas of the present invention will be described by taking the case of using the above-described purifying apparatus 1 as an example. In addition, the refiner | purifier used in this invention is not limited only to the refiner | purifier 1 mentioned above.
In the method for purifying sulfur dioxide gas according to the present embodiment, a sulfur dioxide-containing gas containing sulfur as an impurity is accommodated in the tank body 21 of the sulfuric acid tank 20 through the sulfur dioxide-containing gas flow path 10 of the purification apparatus 1. The sulfuric acid solution is stirred with the stirrer 23 while blowing into the sulfuric acid solution.

Although it does not specifically limit as sulfur dioxide containing gas, For example, the crude sulfur dioxide gas etc. which are obtained by making sulfur and oxygen react are mentioned.
In the present invention, the crude gas obtained by reacting sulfur and oxygen may be used as it is without purification. For example, sulfur in the crude gas may be used in advance by the method described in Patent Document 2, for example. The concentration may be reduced to about 300 mg / kg.

  From the viewpoint of improving sulfur removal efficiency, the blowing rate of the sulfur dioxide-containing gas into the sulfuric acid solution accommodated in the tank body 21 is preferably 1000 kg / hr or less, more preferably as the blowing rate per 2000 kg of the sulfuric acid solution. From the viewpoint of ensuring sufficient production efficiency, it is preferably 50 kg / hr or more, more preferably 100 kg / hr or more.

The sulfuric acid solution is not particularly limited as long as sulfur in the sulfur dioxide-containing gas can be precipitated. Examples of the sulfuric acid solution include a sulfuric acid aqueous solution.
The concentration of sulfuric acid in the sulfuric acid solution is preferably 70% by mass or more, more preferably 80% by mass or more, and further preferably from the viewpoint of suppressing the solvent used in the sulfuric acid solution from being mixed into the obtained sulfur dioxide gas. Is 90% by mass or more, and preferably 98.6% by mass or less from the viewpoint of suppressing sulfur trioxide from being mixed into the obtained sulfur dioxide gas.

Such a sulfuric acid solution has a temperature difference from the sulfur dioxide-containing gas.
The temperature difference between the sulfur dioxide-containing gas and the sulfuric acid solution is preferably 5 ° C. or higher, more preferably 10 ° C. or higher, from the viewpoint of improving sulfur removal efficiency. Therefore, it is preferably 150 ° C. or lower, more preferably 80 ° C. or lower.
Although the temperature of a sulfuric acid solution is not specifically limited, From a viewpoint of improving the removal efficiency of sulfur, Preferably it is -5-80 degreeC, and is a temperature different from the temperature of sulfur dioxide containing gas.
Note that the temperature of the sulfuric acid solution may be higher or lower than the temperature of the sulfur dioxide-containing gas.
On the other hand, the temperature of the sulfur dioxide-containing gas is not particularly limited, but is preferably 10 to 115 ° C. and a temperature different from the temperature of the sulfuric acid solution from the viewpoint of improving sulfur removal efficiency.

The stirring speed by the stirrer 23 can be appropriately set within a range in which the bubbles of the sulfur dioxide-containing gas can be refined according to the amount of the sulfuric acid solution, a desired purification speed, and the like.
In the present invention, the sulfuric acid solution need not be stirred when the sulfur dioxide-containing gas is blown into the sulfuric acid solution. In this case, the purification apparatus used may not include a stirrer.

  In the sulfuric acid tank 20, sulfur dioxide gas generated by blowing sulfur dioxide-containing gas into the sulfuric acid solution can be recovered from the sulfur dioxide gas flow path 30. The sulfur dioxide gas thus obtained usually has a sulfur concentration of 1 mg / kg or less. In the present invention, when the sulfur dioxide gas is recovered, the sulfur dioxide gas can be appropriately dried.

  The sulfuric acid solution used for the purification of the sulfur dioxide gas is passed through the sulfuric acid solution regeneration flow path 40, whereby the sulfur deposits in the sulfuric acid solution are removed and regenerated. The regenerated sulfuric acid solution can be reused by returning it to the sulfuric acid tank 20 via the sulfuric acid solution return flow path 50.

  Further, in the present invention, for example, the temperature difference between the sulfur dioxide-containing gas and the sulfuric acid solution may be adjusted by heating or cooling the sulfur dioxide-containing gas in the middle of the sulfur dioxide-containing gas flow path 10. Good.

  As described above, according to the method and apparatus for purifying sulfur dioxide gas of the present invention, the sulfur concentration in sulfur dioxide gas can be reduced to 1 mg / kg or less. Since this sulfur dioxide gas has a reduced sulfur concentration, it can be used in various applications such as food additives that require high purity sulfur dioxide gas with a reduced sulfur content. Therefore, the method and apparatus for purifying sulfur dioxide gas of the present invention is very useful in fields including food fields where high-purity sulfur dioxide gas with reduced sulfur content is required.

  Hereinafter, the present invention will be described in detail with reference to examples. However, the present invention is not limited to these examples.

(Production Example 1)
Oxygen gas (oxygen concentration: 99.8% by volume) was blown into 1 L of liquid sulfur maintained at a temperature of 400 ° C. at a flow rate of 1 L / min to react oxygen and sulfur, and the generated gas was brought to 130 to 150 ° C. Upon cooling, a sulfur dioxide-containing gas was obtained. The sulfur concentration of the obtained sulfur dioxide-containing gas was 500 mg / kg.

Example 1
2000 kg of 98 mass% sulfuric acid aqueous solution was charged into the tank body 21 of the sulfuric acid tank 20 of the purification apparatus 1 shown in FIG. 1, and the temperature of the sulfuric acid aqueous solution was adjusted to 30 ° C. In addition, as the diffuser tube 22 of the purification apparatus 1 shown in FIG. 1, an diffuser tube having an inner diameter of 10 cm, a nozzle hole diameter of 10 cm, and a nozzle shape having a straight tube shape was used. In addition, a tank body having an inner diameter of 2 m and a height of 3 m was used as the tank body 21. Next, the temperature of the sulfur dioxide-containing gas obtained in Production Example 1 was adjusted to 20 ° C. The sulfuric acid aqueous solution was stirred with a stirrer 23 while blowing the sulfur dioxide-containing gas into the sulfuric acid aqueous solution in the tank body 21 at a flow rate of 500 kg / hr through the air diffuser 22. And the sulfur dioxide gas which distribute | circulates the sulfur dioxide gas flow path 30 was collect | recovered.

(Example 2)
In Example 1, operation was performed in the same manner as in Example 1 except that an 80% by mass sulfuric acid aqueous solution was used in place of the 98% by mass sulfuric acid aqueous solution to obtain sulfur dioxide gas.

(Example 3)
In Example 1, operation was performed in the same manner as in Example 1 except that a 90% by mass sulfuric acid aqueous solution was used in place of the 98% by mass sulfuric acid aqueous solution to obtain sulfur dioxide gas.

Example 4
In Example 1, operation was performed in the same manner as in Example 1 except that a 70% by mass sulfuric acid aqueous solution was used instead of the 98% by mass sulfuric acid aqueous solution to obtain sulfur dioxide gas.

(Example 5)
In Example 1, operation was performed in the same manner as in Example 1 except that a 99% by mass sulfuric acid aqueous solution was used in place of the 98% by mass sulfuric acid aqueous solution to obtain sulfur dioxide gas.

(Example 6)
In Example 1, the temperature of the sulfuric acid aqueous solution was adjusted to 80 ° C. instead of adjusting to 30 ° C., and the temperature of the sulfur dioxide-containing gas was adjusted to 115 ° C. instead of adjusting to 20 ° C. Example 1 In the same manner as described above, sulfur dioxide gas was obtained.

(Example 7)
Example 1 except that the temperature of the aqueous sulfuric acid solution was adjusted to 40 ° C. instead of adjusting to 30 ° C. and that the temperature of the sulfur dioxide-containing gas was adjusted to 100 ° C. instead of adjusting to 20 ° C. In the same manner as described above, sulfur dioxide gas was obtained.

(Example 8)
Example 1 except that the temperature of the sulfuric acid aqueous solution was adjusted to 35 ° C. instead of adjusting to 30 ° C. and that the temperature of the sulfur dioxide-containing gas was adjusted to 38 ° C. instead of adjusting to 20 ° C. In the same manner as described above, sulfur dioxide gas was obtained.

Example 9
In the first embodiment, the diffuser tube 22 of the purification apparatus 1 shown in FIG. 1 is replaced with a diffuser tube having a porous nozzle shape instead of a straight tube shape of the nozzle hole. Sulfur dioxide gas was obtained in the same manner as in Example 1 except that it was used and stirring with a stirrer was not performed.
In addition, it was confirmed that the crystal | crystallization of sulfur has adhered to the front-end | tip of the nozzle of a diffuser tube.

(Comparative Example 1)
The sulfur dioxide-containing gas was passed through a cooling pipe maintained at 500 kg / hr and a temperature of 115 ° C to 110 ° C. At this time, the temperature of the gas at the outlet of the cooling pipe was 110 ° C.

(Test example)
The sulfur dioxide gas obtained in Examples 1 to 9 and the concentrations of sulfur, water and sulfur trioxide in the gas obtained in Comparative Example 1 were measured. The results are shown in Table 1.

From the results shown in Table 1, it was obtained when a sulfur dioxide-containing gas containing sulfur as an impurity was blown into a sulfuric acid solution having a temperature difference from the sulfur dioxide-containing gas (Examples 1 to 9). It can be seen that the sulfur dioxide gas has a lower sulfur concentration than the gas obtained when the sulfur dioxide-containing gas is cooled as in the conventional method (Comparative Example 1). Further, the water concentration and sulfur trioxide concentration of the sulfur dioxide gas obtained by the methods described in Examples 1 to 9 are practically acceptable concentrations.
In the methods described in Examples 1 to 9, a conventional operation is simply performed by blowing a sulfur dioxide-containing gas containing sulfur as an impurity into a sulfuric acid solution having a temperature difference from the sulfur dioxide-containing gas. A high-purity sulfur dioxide gas having a sulfur content reduced as compared with the method can be obtained.
Therefore, from these results, the sulfur content was reduced as compared with the conventional method by blowing a sulfur dioxide-containing gas containing sulfur as an impurity into a sulfuric acid solution having a temperature difference from the sulfur dioxide-containing gas. High purity sulfur dioxide gas can be obtained easily and efficiently.

Further, from the results shown in Table 1, when the concentration of sulfuric acid in the sulfuric acid aqueous solution is 70% by mass or more, the concentration of water in the sulfur dioxide gas is a concentration that does not hinder use for various purposes (110 mg / kg) It turns out that it is below.
Therefore, from these results, when the concentration of sulfuric acid in the sulfuric acid aqueous solution is 70% by mass or more, preferably 80% by mass or more, more preferably 90% by mass or more, the sulfur content is reduced as compared with the conventional method. It can be seen that high-purity sulfur dioxide gas can be obtained.

Furthermore, from the results shown in Table 1, when the temperature difference between the temperature of the sulfuric acid aqueous solution and the temperature of the sulfur dioxide-containing gas is at least 5 ° C. (see Examples 1 to 7), the temperature difference is 3 ° C. It can be seen that a sulfur dioxide gas having a higher purity than that obtained in Example 8 is obtained.
Therefore, it can be seen from these results that the temperature difference is preferably at least 5 ° C.

DESCRIPTION OF SYMBOLS 1 Purification apparatus 10 Sulfur dioxide containing gas flow path 20 Sulfuric acid tank 21 Tank main body 22 Aeration pipe 23 Stirrer 40 Sulfuric acid solution regeneration flow path 50 Sulfuric acid solution return flow path

Claims (6)

Comprises sulfur as an impurity, and the 10-115 ° C. sulfur dioxide-containing gas, have a temperature difference of 5 to 150 ° C. between the sulfur dioxide-containing gas, and at a sulfuric acid concentration of 70 to 98.6 wt% by blowing Oh Ru in sulfuric acid solution at a blowing speed of the sulphate solution 2000kg per 50~1000kg / hr, the sulfur is removed by precipitation in the sulfuric acid solution, wherein the obtained sulfur dioxide gas, sulfur dioxide Gas purification method. By stirring while blowing a sulfur dioxide-containing gas into sulfuric acid solution, to finer bubbles sulfur dioxide-containing gas formed in the sulfuric acid solution method for purifying sulfur dioxide gas according to claim 1. Before SL sulfuric acid solution is an aqueous solution sulfuric acid method of purifying sulfur dioxide gas according to claim 1 or 2. A sulfur dioxide gas purifier for purifying sulfur dioxide gas from a sulfur dioxide-containing gas containing sulfur as an impurity, using the sulfur dioxide gas purification method according to any one of claims 1 to 3 ,
A sulfate bath have a temperature difference of 5 to 150 ° C., and the sulfuric acid concentration to accommodate a 70 to 98.6% by mass Ru sulfuric acid solution between the sulfur dioxide-containing gas,
A sulfur dioxide-containing gas stream that conveys the sulfur dioxide-containing gas to the sulfuric acid tank and blows the sulfur dioxide-containing gas at 10 to 115 ° C. into the sulfuric acid solution at a blowing speed of 50 to 1000 kg / hr per 2000 kg of the sulfuric acid solution. Road,
An apparatus for purifying sulfur dioxide gas, comprising: On the downstream side of the sulfuric acid tank, a sulfuric acid solution regeneration flow path for regenerating the sulfuric acid solution by removing sulfur from the sulfuric acid solution containing sulfur deposits, and a sulfuric acid solution return flow path for returning the regenerated sulfuric acid solution to the sulfuric acid tank The apparatus for purifying sulfur dioxide gas according to claim 4 , further comprising: The sulfuric acid tank is
A tank body containing a sulfuric acid solution;
An aeration tube that is installed in the tank body and blows bubbles of sulfur dioxide-containing gas into the sulfuric acid solution;
It is disposed above the aeration tube of the tank body, and stirring the sulfuric acid solution in which the bubble is blown and an agitator to miniaturize the bubble dioxide according to claim 4 or 5 Sulfur gas purification equipment.

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