Exhaust gas treatment device, exhaust gas treatment method, and method for producing sulfide compound

Abstract

Provided are an exhaust gas treatment device, an exhaust gas treatment method, and a method for producing a sulfide compound, the exhaust gas treatment device being capable of suppressing damage to components constituting a combustion chamber even when an exhaust gas containing a high concentration of hydrogen sulfide is treated at a high temperature, and being capable of performing a treatment of removing sulfur dioxide. And the waste gas treatment device is used for treating waste gas containing hydrogen sulfide. This exhaust gas treatment device is provided with: a combustion furnace for combusting hydrogen sulfide contained in exhaust gas and converting the hydrogen sulfide into sulfur dioxide; and a scrubber for converting the sulfur dioxide converted in the combustion furnace into sulfite by bringing the sulfur dioxide into contact with an alkaline aqueous solution. A combustion furnace (11) is provided with a first introduction pipe (21) for introducing exhaust gas, a second introduction pipe (22) for introducing combustible gas and combustion-supporting gas, and a combustion chamber (23) connected to the first introduction pipe (21) and the second introduction pipe (22). A member constituting the combustion chamber (23) is provided with quartz glass on the surface of the inner side of the combustion chamber (23).

Description

Technical Field

[0001] The present invention relates to an exhaust gas treatment device, an exhaust gas treatment method and a method for producing a sulfide compound. Background Art

[0002] Sulfide compounds have been used in cathode ray tube (TV) phosphors, and more recently in photocatalysts for artificial photosynthesis and solid electrolytes for all-solid-state batteries. The synthesis of these sulfide compounds presents a significant challenge in terms of supplying the sulfur source required for the reaction. From the perspectives of temperature flexibility and mass production, methods for synthesizing sulfide compounds by continuously supplying hydrogen sulfide for reaction are desired.

[0003] Meanwhile, hydrogen sulfide is a toxic and flammable gas, making it a regulated substance under various laws and regulations. Therefore, various safety measures are essential for its handling. However, industrial use of raw gas containing high concentrations of hydrogen sulfide is rare, and there are no methods for treating waste gas containing high concentrations of hydrogen sulfide. Hydrogen sulfide has a rancid odor, making it a target of malodor control laws. However, the concentration at which humans cannot detect malodor is extremely low, below 0.02 ppm by volume.

[0004] Patent Document 1 describes a combustion-type exhaust gas treatment device that removes harmful components by ejecting exhaust gas containing harmful components into a combustion chamber and burning it. The combustion chamber is formed using a double-walled structure consisting of an inner wall and an outer wall. The inner wall is made of a porous material, and a gas inlet is provided between the inner and outer walls for introducing pressurized gas. The porous material is made of sintered stainless steel with a nominal filtration accuracy of 100 μm.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Laid-Open No. 10-54534 Summary of the Invention

[0008] Problems to be solved by the invention

[0009] However, when using the combustion-type exhaust gas treatment device described in Patent Document 1 to treat exhaust gas containing high concentrations of hydrogen sulfide at high temperatures, the inner wall of the combustion chamber corrodes, resulting in damage. Furthermore, sulfur dioxide generated by the combustion of hydrogen sulfide requires detoxification due to emission standards established under the Air Pollution Control Act.

[0010] An object of the present invention is to provide an exhaust gas treatment device capable of suppressing damage to components constituting a combustion chamber and removing sulfur dioxide even when treating exhaust gas containing a high concentration of hydrogen sulfide at a high temperature.

[0011] Methods for solving problems

[0012] (1) A waste gas treatment device for treating waste gas containing hydrogen sulfide, comprising a combustion furnace for burning the hydrogen sulfide contained in the waste gas to convert it into sulfur dioxide, and a scrubber for bringing the sulfur dioxide converted in the combustion furnace into contact with an alkaline aqueous solution to convert it into sulfite; the combustion furnace comprises a first inlet pipe for introducing the waste gas, a second inlet pipe for introducing a combustible gas and an oxidizing gas, and a combustion chamber connected to the first inlet pipe and the second inlet pipe; and components constituting the combustion chamber have quartz glass on the surface of the inner side of the combustion chamber.

[0013] (2) A method for treating exhaust gas, comprising treating the exhaust gas using the exhaust gas treatment device described in (1), wherein the exhaust gas has a concentration of hydrogen sulfide of 20% by volume or more and a combustion temperature of the hydrogen sulfide of 670° C. or more and 1000° C. or less.

[0014] (3) The exhaust gas treatment method according to (2), wherein the pH of the alkaline aqueous solution is 12.1 or higher and 12.3 or lower.

[0015] (4) The exhaust gas treatment method according to (2) or (3), wherein the concentrations of the sulfite and the carbonate converted by contact of the alkaline aqueous solution with carbon dioxide in the alkaline aqueous solution are respectively less than 50% of the solubility of the sulfite and the carbonate in water.

[0016] (5) A method for producing a sulfide compound, comprising the steps of continuously supplying hydrogen sulfide to react and synthesizing the sulfide compound, and treating the waste gas discharged during the synthesis of the sulfide compound by the waste gas treatment method according to any one of (2) to (4).

[0017] Effects of the Invention

[0018] According to the present invention, it is possible to provide an exhaust gas treatment device capable of suppressing damage to components constituting a combustion chamber and removing harm from sulfur dioxide even when treating exhaust gas containing high concentrations of hydrogen sulfide at high temperatures. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram showing an exhaust gas treatment device according to one embodiment of the present invention.

[0020] Figure 2 Yes Figure 1 A partial cross-sectional schematic diagram of the main components of the combustion furnace.

[0021] Figure 3 yes Figure 2 A partially enlarged cross-sectional view and a partially enlarged top view of the combustion furnace.

[0022] Description of Reference Numerals

[0023] 10: Exhaust gas treatment device, 11: Combustion furnace, 12: Scrubber, 21: First inlet pipe, 22: Second inlet pipe, 23: Combustion chamber, 31A, 31B: Outer cylinder, 32A, 32B: Bottom plate, 33A, 33B: Inner cylinder, 33C: Inner cylinder with cover, 34: Conical member, 34a: Conical portion, 34b: Cylindrical portion, T: Through hole. DETAILED DESCRIPTION

[0024] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0025] [Exhaust gas treatment device]

[0026] Figure 1 An exhaust gas treatment device according to one embodiment of the present invention is shown.

[0027] Exhaust gas treatment device 10 is a device for treating exhaust gas containing hydrogen sulfide. It includes a combustion furnace 11 that burns hydrogen sulfide contained in the exhaust gas to convert it into sulfur dioxide, and a scrubber 12 that converts the sulfur dioxide converted in combustion furnace 11 into sulfites by contacting the sulfur dioxide with an alkaline aqueous solution. Thus, the sulfur dioxide converted in combustion furnace 11 is detoxified.

[0028] like Figure 2 As shown, the combustion furnace 11 includes a first inlet pipe 21 for introducing exhaust gas, a second inlet pipe 22 for introducing combustible gas (e.g., liquefied petroleum gas (LPG)) and combustion-supporting gas (e.g., air), and a combustion chamber 23 connected to the first and second inlet pipes 21 and 22. The second inlet pipe 22 includes an ignition mechanism. The components constituting the combustion chamber 23 have quartz glass on their inner surfaces. Specifically, the components constituting the combustion chamber 23 are made of quartz glass, or the inner surfaces of the combustion chamber 23 are covered with quartz glass. Therefore, even when treating exhaust gas containing a high concentration of hydrogen sulfide at high temperatures, damage caused by corrosion of the components constituting the combustion chamber 23 can be suppressed.

[0029] like Figure 3As shown in (a) and (b), the combustion chamber 23 has a quartz glass outer cylinder 31B fitted onto the inner surface of a stainless steel outer cylinder 31A. Furthermore, a quartz glass bottom plate 32B is fitted onto the upper surface of a stainless steel bottom plate 32A. Furthermore, a quartz glass inner cylinder 33B and a covered inner cylinder 33C are fitted onto the outer and inner surfaces, respectively, of a stainless steel inner cylinder 33A extending from the connection with the second inlet pipe 22. The lid of the covered inner cylinder 33C is in contact with the upper surface of the inner cylinder 33A. Furthermore, a quartz glass tapered member 34 of the combustion chamber 23 is fitted onto the quartz glass outer cylinder 31B and inner cylinder 33B. The tapered member 34 comprises a tapered portion 34a and a cylindrical portion 34b, with a through-hole T formed in the tapered portion 34a. At this time, the through hole T serves as a flow path for the exhaust gas introduced from the first introduction pipe 21 into the combustion chamber 23 .

[0030] The scrubber 12 is not particularly limited as long as it can convert sulfur dioxide into sulfite by contacting the alkaline aqueous solution, and a known scrubber can be used. An example of a commercially available scrubber is the wet scrubber SC-100 (manufactured by Seiko Kako Ki).

[0031] [Waste gas treatment method]

[0032] The exhaust gas treatment method of the present embodiment is a method of treating exhaust gas containing hydrogen sulfide using the exhaust gas treatment device 10. The concentration of hydrogen sulfide in the exhaust gas is 20% by volume or more and 100% by volume or less.

[0033] First, a method for burning hydrogen sulfide contained in exhaust gas and converting it into sulfur dioxide using the combustion furnace 11 will be described. In the combustion chamber 23, the combustible gas introduced through the second inlet pipe 22 burns to generate a flame, and hydrogen sulfide burns above the flame. The combustion temperature of hydrogen sulfide is between 670°C and 1000°C. The combustion temperature of hydrogen sulfide is adjusted by the amount of combustible gas and combustion-supporting gas introduced. The method for detecting the combustion temperature of hydrogen sulfide is not particularly limited; for example, a method using a thermocouple in the hydrogen sulfide combustion area can be used. Furthermore, the concentration of hydrogen sulfide in the combustion chamber 23 is within the combustion range of hydrogen sulfide (between 4.3% and 46% by volume). The concentration of hydrogen sulfide in the combustion chamber 23 is adjusted by the amount of exhaust gas and combustion-supporting gas introduced.

[0034] The combustible gas is not particularly limited as long as it can burn to generate flames, and an example thereof is LPG. The combustion-supporting gas is not particularly limited as long as it can burn the combustible gas and hydrogen sulfide, and an example thereof is air.

[0035] Next, a method of converting sulfur dioxide obtained by conversion in the combustion furnace 11 into sulfite by bringing the sulfur dioxide into contact with an alkaline aqueous solution using the scrubber 12 will be described.

[0036] The alkaline aqueous solution is not particularly limited as long as it can convert sulfur dioxide into sulfite, and an example thereof includes a sodium hydroxide aqueous solution.

[0037] The pH of the alkaline aqueous solution is 12.1 or higher and 12.3 or lower. If the pH of the alkaline aqueous solution is lower than 12.1, it is difficult for sulfur dioxide to be converted into sulfite at the desired reaction rate. If the pH exceeds 12.3, the glass electrode of the pH meter used to measure the pH of the alkaline aqueous solution cannot be used for a long time.

[0038] The method for controlling the pH of the alkaline aqueous solution is not particularly limited, and examples thereof include a method of replenishing the alkaline aqueous solution with a concentrated alkaline aqueous solution or water based on the measured pH value of the alkaline aqueous solution, and a method of replacing the alkaline aqueous solution.

[0039] In the exhaust gas treatment method of this embodiment, combustible gas is burned in combustion chamber 23 to produce carbon dioxide. Therefore, the combustion gas discharged from combustion furnace 11 inevitably contains carbon dioxide. Therefore, when the sulfur dioxide converted in combustion furnace 11 comes into contact with an alkaline aqueous solution, the carbon dioxide comes into contact with the alkaline aqueous solution and is converted into carbonates. As a result, if the concentration of sulfite (or carbonate) in the alkaline aqueous solution exceeds 50% of the solubility of sulfite (or carbonate) in water, sulfur dioxide may be difficult to convert into sulfite. Therefore, the concentrations of sulfite and carbonate in the alkaline aqueous solution are preferably no more than 50% of the solubility of sulfite and carbonate in water, respectively.

[0040] There are no particular limitations on the method for managing the concentrations of sulfites and carbonates in the alkaline aqueous solution. For example, there can be mentioned a method of replenishing the alkaline aqueous solution with a concentrated alkaline aqueous solution or water at a specified timing based on the amount of sulfur dioxide and carbon dioxide introduced into the scrubber 12, or a method of replacing the alkaline aqueous solution.

[0041] The exhaust gas treatment method of the present embodiment can be applied to the treatment of exhaust gas discharged when, for example, hydrogen sulfide is continuously supplied and reacted to synthesize a known sulfide compound.

[0042] As mentioned above, although embodiment of this invention was demonstrated, this invention is not limited to the said embodiment, The said embodiment can also be modified suitably within the range of the summary of this invention.

[0043] Example

[0044] Next, examples of the present invention will be described, but the present invention is not limited to the examples.

[0045] [Comparative Example 1]

[0046] The combustion furnace 11 of the exhaust gas treatment device 10 is used to treat hydrogen sulfide. Specifically, the combustion furnace 11 is used to burn hydrogen sulfide and convert it into sulfur dioxide. At this time, hydrogen sulfide (10 L / min) and air (30 L / min) are introduced to adjust the concentration of hydrogen sulfide in the combustion chamber 23 to 25% by volume. In addition, a thermocouple is installed in the combustion area of ​​hydrogen sulfide to manage the amount of LPG and air introduced so that the temperature of the combustion chamber 23 is above 670°C and below 1000°C. Next, air (20 m3 / min) is introduced into the combustion gas discharged from the combustion chamber 23. 3 / min) for dilution.

[0047] [Example 1]

[0048] The scrubber 12 of the exhaust gas treatment device 10 is heated to 20 m 3 / min, the treated gas of Comparative Example 1 is introduced and brought into contact with the sodium hydroxide aqueous solution to be converted into sodium sulfite. At this time, the pH of the sodium hydroxide aqueous solution is managed to be above 12.1 and below 12.3 using a pH regulator HBM-100A (manufactured by DKK East Asia) installed in the scrubber 12. Specifically, based on the measured pH value, the concentrated sodium hydroxide aqueous solution is added to the sodium hydroxide aqueous solution. In addition, the concentrations of sodium sulfite and sodium carbonate in the sodium hydroxide aqueous solution are managed in such a manner that the concentrations of sodium sulfite and sodium carbonate in the sodium hydroxide aqueous solution are below 50% (below 150 g / L and below 90 g / L) of the solubility of sodium sulfite and sodium carbonate in the sodium hydroxide aqueous solution at the liquid temperature (20°C), respectively. Specifically, based on the amount of sulfur dioxide and carbon dioxide introduced into the scrubber 12, water is supplied to the sodium hydroxide aqueous solution at a specified time.

[0049] [Comparative Example 2]

[0050] Hydrogen sulfide was treated in the same manner as in Comparative Example 1, except that the quartz glass components constituting the combustion chamber 23 were replaced with stainless steel (SUS304) components.

[0051] [Concentrations of hydrogen sulfide, sulfur dioxide, and carbon dioxide in the treated gas]

[0052] The concentrations of hydrogen sulfide, sulfur dioxide, and carbon dioxide in the gas were measured using a detector tube (manufactured by GASTEC) or the like.

[0053] [Extent of damage to components constituting the combustion chamber]

[0054] When the cumulative usage time of the combustion furnace 11 reached 300 hours, the degree of damage of the components constituting the combustion chamber 23 was visually evaluated.

[0055] Table 1 shows the concentrations of hydrogen sulfide, sulfur dioxide, and carbon dioxide in the treatment gas and the evaluation results of the degree of damage of the components constituting the combustion chamber.

[0056] [Table 1]

[0057]

[0058] As shown in Table 1, in Example 1, even when hydrogen sulfide was treated at high temperatures, damage to the components constituting the combustion chamber 23 was suppressed, and sulfur dioxide was detoxified. In contrast, in Comparative Example 1, since the scrubber 12 was not used, sulfur dioxide was not detoxified. Furthermore, in Comparative Example 2, the presence of SUS304 on the inner surface of the combustion chamber 23 caused damage to the components constituting the combustion chamber 23.

Claims

1. A waste gas treatment device, which is a device for treating waste gas containing hydrogen sulfide, have: a combustion furnace that burns hydrogen sulfide contained in the exhaust gas to convert it into sulfur dioxide, and a scrubber that converts sulfur dioxide obtained by conversion in the combustion furnace into sulfite by contacting the sulfur dioxide with an alkaline aqueous solution; The combustion furnace includes a first introduction pipe for introducing the exhaust gas, a second introduction pipe for introducing the combustible gas and the combustion-supporting gas, and a combustion chamber connected to the first introduction pipe and the second introduction pipe; Quartz glass is present on the surface of the inner side of the combustion chamber of the member constituting the combustion chamber.

2. A method for treating waste gas, comprising treating the waste gas using the waste gas treatment device according to claim 1. The concentration of hydrogen sulfide in the exhaust gas is above 20% by volume, The combustion temperature of the hydrogen sulfide is 670° C. or higher and 1000° C. or lower.

3. The waste gas treatment method according to claim 2, wherein: The pH of the alkaline aqueous solution is 12.1 or higher and 12.3 or lower.

4. The waste gas treatment method according to claim 2 or 3, wherein: In the alkaline aqueous solution, the concentrations of the sulfite and the carbonate converted by contacting the alkaline aqueous solution with carbon dioxide are respectively less than 50% of the solubility of the sulfite and the carbonate in water.

5. A method for producing a sulfide compound, comprising: A process of continuously supplying hydrogen sulfide and reacting it to synthesize a sulfide compound, and A step of treating the waste gas discharged during the synthesis of the sulfide compound by the waste gas treatment method according to claim 2 or 3.

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