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

Abstract

To provide an exhaust gas treatment device capable of suppressing damage of a component constituting a combustion chamber and removing sulfur dioxide even when treating exhaust gas containing highly concentrated hydrogen sulfide at high temperature.SOLUTION: An exhaust gas treatment device is a device for treating exhaust gas containing hydrogen sulfide. The exhaust gas treatment device includes: a combustion furnace for burning and converting hydrogen sulfide included in exhaust gas into sulfur dioxide; and a scrubber that causes the sulfur dioxide converted in the combustion furnace to come into contact with an alkaline aqueous solution for conversion into subsulfate. The combustion furnace 11 includes: 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. In a component constituting the combustion chamber 23, silica glass is present on a surface on an indoor side of the combustion chamber 23.SELECTED DRAWING: Figure 2

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 technology]

[0002] Sulfide compounds have long been used as phosphors for cathode ray tube TVs, and more recently as photocatalysts for artificial photosynthesis and solid electrolytes for all-solid-state batteries. A major challenge in synthesizing these sulfide compounds is how to supply the sulfur source necessary for the reaction. From the perspectives of flexibility in reaction temperature and mass production, a method for synthesizing sulfide compounds by continuously supplying hydrogen sulfide and carrying out a reaction has been desired.

[0003] On the other hand, hydrogen sulfide is a toxic and flammable gas, and is subject to regulation under various laws and regulations. Therefore, various safety measures are essential when handling hydrogen sulfide. However, there are few opportunities to use raw material gases containing high concentrations of hydrogen sulfide industrially, and no methods exist for treating exhaust gases containing high concentrations of hydrogen sulfide. Hydrogen sulfide has a rotten egg odor, and is therefore subject to the Offensive Odor Prevention Act. However, the concentration at which humans no longer perceive it as an offensive odor is extremely low, at 0.02 ppm by volume or less.

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

[0005] [Patent Document 1] Japanese Patent Application Publication No. 10-54534 Summary of the Invention [Problem to be solved by the invention]

[0006] However, when exhaust gas containing a high concentration of hydrogen sulfide is treated at high temperatures using the combustion-type exhaust gas treatment device described in Patent Document 1, the inner wall of the combustion chamber corrodes, resulting in damage to the inner wall of the combustion chamber.In addition, sulfur dioxide produced by burning hydrogen sulfide is subject to emission standards set by the Air Pollution Control Act, so it needs to be removed.

[0007] The present invention aims to provide an exhaust gas treatment device that can suppress damage to components constituting a combustion chamber and remove sulfur dioxide, even when treating exhaust gas containing a high concentration of hydrogen sulfide at high temperatures. [Means for solving the problem]

[0008] (1) An exhaust gas treatment device that treats exhaust gas containing hydrogen sulfide, comprising: a combustion furnace that burns the hydrogen sulfide contained in the exhaust gas to convert it to sulfur dioxide; and a scrubber that brings the sulfur dioxide converted in the combustion furnace into contact with an alkaline aqueous solution to convert it to sulfite; the combustion furnace comprises a first inlet pipe for introducing the exhaust gas, a second inlet pipe for introducing a combustible gas and a combustion-supporting gas, and a combustion chamber connected to the first inlet pipe and the second inlet pipe; and components that constitute the combustion chamber include quartz glass on the surface of the combustion chamber facing the interior.

[0009] (2) A method for treating an exhaust gas using the exhaust gas treatment device according to (1), wherein the exhaust gas has a hydrogen sulfide concentration of 20% by volume or more, and the combustion temperature of the hydrogen sulfide is 670°C or more and 1000°C or less.

[0010] (3) The exhaust gas treatment method according to (2), wherein the alkaline aqueous solution has a pH of 12.1 or more and 12.3 or less.

[0011] (4) The exhaust gas treatment method according to (2) or (3), wherein the alkaline aqueous solution has concentrations of the sulfite and carbonate converted by contact of the alkaline aqueous solution with carbon dioxide that are 50% or less of the solubility of the sulfite and carbonate in water, respectively.

[0012] (5) A method for producing a sulfide compound, comprising: a step of continuously supplying hydrogen sulfide and reacting it to synthesize a sulfide compound; and a step of treating exhaust gas emitted during the synthesis of the sulfide compound by the exhaust gas treatment method according to any one of (2) to (4). [Effects of the Invention]

[0013] According to the present invention, it is possible to provide an exhaust gas treatment device that can suppress damage to components that make up the combustion chamber and remove sulfur dioxide, even when treating exhaust gas containing a high concentration of hydrogen sulfide at high temperatures. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a schematic diagram illustrating an exhaust gas treatment device according to one embodiment of the present invention. [Figure 2] FIG. 2 is a partial cross-sectional schematic view showing the main configuration of the combustion furnace of FIG. [Figure 3] 3A and 3B are a partially enlarged cross-sectional view and a partially enlarged top view of the combustion furnace of FIG. 2. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0016] [Exhaust gas treatment equipment] FIG. 1 shows an exhaust gas treatment device according to one embodiment of the present invention.

[0017] The exhaust gas treatment device 10 is a device for treating exhaust gas containing hydrogen sulfide, and includes a combustion furnace 11 that burns the hydrogen sulfide contained in the exhaust gas to convert it into sulfur dioxide, and a scrubber 12 that brings the sulfur dioxide converted in the combustion furnace 11 into contact with an alkaline aqueous solution to convert it into sulfite. Thus, the sulfur dioxide converted in the combustion furnace 11 is detoxified.

[0018] As shown in FIG. 2, the combustion furnace 11 includes a first inlet pipe 21 for introducing exhaust gas, a second inlet pipe 22 for introducing a combustible gas (e.g., liquefied petroleum gas (LPG)) and a combustion-supporting gas (e.g., air), and a combustion chamber 23 connected to the first inlet pipe 21 and the second inlet pipe 22. The second inlet pipe 22 is equipped with an ignition mechanism. The components constituting the combustion chamber 23 have quartz glass on their interior surfaces. That is, the components constituting the combustion chamber 23 are made of quartz glass, or the interior surfaces of the combustion chamber 23 are coated with quartz glass. Therefore, even when exhaust gas containing a high concentration of hydrogen sulfide is treated at high temperatures, damage to the components constituting the combustion chamber 23 due to corrosion is suppressed.

[0019] As shown in FIGS. 3(a) and 3(b), the combustion chamber 23 has a quartz glass outer cylinder 31B fitted to the inner surface of a stainless steel outer cylinder 31A. The combustion chamber 23 also has a quartz glass bottom plate 32B fitted to the upper surface of a stainless steel bottom plate 32A. Furthermore, the combustion chamber 23 has a quartz glass inner cylinder 33B and a lidded inner cylinder 33C fitted to the outer and inner surfaces, respectively, of a stainless steel inner cylinder 33A extending from the connection with the second introduction pipe 22. The lid of the lidded inner cylinder 33C is in contact with the upper surface of the inner cylinder 33A. Furthermore, the combustion chamber 23 has a quartz glass cone-shaped member 34 fitted to the quartz glass outer cylinder 31B and inner cylinder 33B. The cone-shaped member 34 includes a cone portion 34a and a cylindrical portion 34b, and a through-hole T is formed in the cone 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.

[0020] The scrubber 12 is not particularly limited as long as it is capable of converting sulfur dioxide into sulfite by contacting it with an alkaline aqueous solution, and any known scrubber can be used. An example of a commercially available scrubber is the wet scrubber SC-100 (manufactured by Seiko Kakoki Co., Ltd.).

[0021] [Exhaust gas treatment method] The exhaust gas treatment method of this embodiment is a method for treating exhaust gas containing hydrogen sulfide using an 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.

[0022] First, a method for burning hydrogen sulfide contained in exhaust gas to convert it to sulfur dioxide using the combustion furnace 11 will be described. In the combustion chamber 23, combustible gas introduced from the second introduction pipe 22 burns to generate a flame, and hydrogen sulfide burns above the flame. The combustion temperature of hydrogen sulfide is 670°C or higher and 1000°C or lower. At this time, the combustion temperature of hydrogen sulfide is adjusted by the amount of introduced combustible gas and combustion-supporting gas. The method for detecting the combustion temperature of hydrogen sulfide is not particularly limited, but an example is a method of installing a thermocouple in the hydrogen sulfide combustion zone. Furthermore, the concentration of hydrogen sulfide in the combustion chamber 23 is within the flammable range of hydrogen sulfide (4.3% by volume or higher and 46% by volume or lower). At this time, the concentration of hydrogen sulfide in the combustion chamber 23 is adjusted by the amount of introduced exhaust gas and combustion-supporting gas.

[0023] The flammable gas is not particularly limited as long as it can be burned to generate a flame, but examples thereof include LPG. The combustion-supporting gas is not particularly limited as long as it can burn the flammable gas and hydrogen sulfide, but examples thereof include air.

[0024] Next, a method for converting sulfur dioxide converted in the combustion furnace 11 into sulfite by contacting it with an alkaline aqueous solution using the scrubber 12 will be described.

[0025] The alkaline aqueous solution is not particularly limited as long as it can convert sulfur dioxide into sulfite, and an example thereof is an aqueous sodium hydroxide solution.

[0026] 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 becomes difficult to convert sulfur dioxide to sulfite at the desired reaction rate. If the pH of the alkaline aqueous solution is higher than 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 period of time.

[0027] The method for controlling the pH of the alkaline aqueous solution is not particularly limited, but examples include a method of replenishing the alkaline aqueous solution with a concentrated alkaline aqueous solution or water based on the measured pH of the alkaline aqueous solution, and a method of replacing the alkaline aqueous solution.

[0028] In the exhaust gas treatment method of this embodiment, combustible gas is burned in the combustion chamber 23 to generate carbon dioxide, and therefore the combustion gas discharged from the combustion furnace 11 necessarily contains carbon dioxide. Therefore, when the sulfur dioxide converted in the combustion furnace 11 is brought into contact with an alkaline aqueous solution, the carbon dioxide comes into contact with the alkaline aqueous solution and is converted to carbonate. 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, it may become difficult to convert sulfur dioxide to sulfite. Therefore, it is preferable that the concentrations of sulfite and carbonate in the alkaline aqueous solution be 50% or less of the solubility of sulfite and carbonate in water, respectively.

[0029] The method for controlling the concentrations of sulfite and carbonate in the alkaline aqueous solution is not particularly limited, but examples include a method of replenishing the alkaline aqueous solution with a concentrated alkaline aqueous solution or water, or a method of replacing the alkaline aqueous solution, at a predetermined timing based on the amounts of sulfur dioxide and carbon dioxide introduced into the scrubber 12.

[0030] The exhaust gas treatment method of this embodiment can be applied to the treatment of exhaust gas emitted when hydrogen sulfide is continuously supplied and reacted to synthesize known sulfide compounds, for example.

[0031] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and the above-described embodiments may be modified as appropriate within the scope of the spirit of the present invention. [Example]

[0032] Next, examples of the present invention will be described, but the present invention is not limited to these examples.

[0033] [Comparative Example 1] Hydrogen sulfide was treated using the combustion furnace 11 of the exhaust gas treatment device 10. Specifically, hydrogen sulfide was burned using the combustion furnace 11 and converted into sulfur dioxide. At this time, hydrogen sulfide (10 L / min) was introduced, and air (30 L / min) was introduced to adjust the hydrogen sulfide concentration in the combustion chamber 23 to 25% by volume. Furthermore, using a thermocouple installed in the hydrogen sulfide combustion region, the amounts of LPG and air introduced were controlled so that the temperature of the combustion chamber 23 was 670°C or higher and 1000°C or lower. Next, air (20 m) was added to the combustion gas discharged from the combustion chamber 23. 3 / min) was introduced and diluted.

[0034] [Example 1] The treated gas of Comparative Example 1 was introduced into the scrubber 12 of the exhaust gas treatment device 10 at 20 m 3The sodium hydroxide solution was introduced at a rate of 1 / min and brought into contact with an aqueous sodium hydroxide solution to convert it to sodium sulfite. The pH of the aqueous sodium hydroxide solution was controlled to be between 12.1 and 12.3 using a pH controller HBM-100A (manufactured by DKK-TOA) installed in the scrubber 12. Specifically, the aqueous sodium hydroxide solution was supplemented with concentrated aqueous sodium hydroxide based on the measured pH. The concentrations of sodium sulfite and sodium carbonate in the aqueous sodium hydroxide solution were controlled to be 50% or less (150 g / L or less and 90 g / L or less) of the solubilities in water of sodium sulfite and sodium carbonate in the aqueous sodium hydroxide solution at the liquid temperature (20°C), respectively. Specifically, water was supplied to the aqueous sodium hydroxide solution at predetermined times based on the amounts of sulfur dioxide and carbon dioxide introduced into the scrubber 12.

[0035] Comparative Example 2 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.

[0036] [Concentrations of hydrogen sulfide, sulfur dioxide, and carbon dioxide in the treated gas] The concentrations of hydrogen sulfide, sulfur dioxide, and carbon dioxide in the gas were measured using detector tubes (manufactured by Gastec).

[0037] [Damage to components that make up the combustion chamber] When the cumulative operating time of the combustion furnace 11 reached 300 hours, the degree of damage to the components constituting the combustion chamber 23 was visually evaluated.

[0038] Table 1 shows the evaluation results of the concentrations of hydrogen sulfide, sulfur dioxide, and carbon dioxide in the treated gas, as well as the degree of damage to the components that make up the combustion chamber.

[0039] [Table 1]

[0040] From Table 1, it can be seen that in Example 1, even when hydrogen sulfide is treated at high temperatures, damage to the components constituting the combustion chamber 23 is suppressed and sulfur dioxide is removed. In contrast, in Comparative Example 1, the scrubber 12 is not used, so sulfur dioxide is not removed. Furthermore, in Comparative Example 2, SUS304 is present on the interior-side surface of the combustion chamber 23, so the components constituting the combustion chamber 23 are damaged. [Explanation of symbols]

[0041] 10. Exhaust gas treatment device 11 Combustion furnace 12 Scrubber 21 1st introduction pipe 22 2nd introduction pipe 23 Combustion chamber 31A, 31B outer cylinder 32A, 32B bottom plate 33A, 33B inner cylinder 33C Inner tube with lid 34 Cone-shaped member 34a Cone section 34b Cylinder part T through hole

Claims

1. An apparatus for treating exhaust gas containing hydrogen sulfide, a combustion furnace for burning hydrogen sulfide contained in the exhaust gas to convert it into sulfur dioxide; a scrubber that converts the sulfur dioxide converted in the combustion furnace into sulfite by contacting the sulfur dioxide with an alkaline aqueous solution; the combustion furnace includes a first inlet pipe for introducing the exhaust gas, a second inlet pipe for introducing a combustible gas and a combustion-supporting gas, and a combustion chamber connected to the first inlet pipe and the second inlet pipe; An exhaust gas treatment device, wherein the components constituting the combustion chamber have quartz glass on the surface of the combustion chamber facing the interior.

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

3. The exhaust gas treatment method according to claim 2 , wherein the alkaline aqueous solution has a pH of 12.1 or more and 12.3 or less.

4. 4. The exhaust gas treatment method according to claim 2, wherein the alkaline aqueous solution has concentrations of the sulfite and the carbonate to be converted upon contact of the alkaline aqueous solution with carbon dioxide that are 50% or less of the solubilities of the sulfite and the carbonate in water, respectively.

5. a step of continuously supplying hydrogen sulfide and reacting it to synthesize a sulfide compound; and treating exhaust gas emitted during synthesis of the sulfide compound by the exhaust gas treatment method according to claim 2 or 3.

Images