JPH0558768B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applicable to natural gas, city gas, LPG, naphtha, various process gases, etc. containing sulfur compounds such as hydrogen sulfide, mercaptans, and sulfides. Alternatively, the present invention relates to a method for removing sulfur compounds from a mixed gas thereof, and a desulfurization agent used in the method. [Prior Art] Conventionally, as a method for removing sulfur compounds in a gas mainly composed of hydrocarbons, for example, hydrogen is added to the gas stream and Ni-Mo based or Ni-Mo-based or A so-called hydrodesulfurization method is known in which sulfur compounds are brought into contact with a Co-Mo catalyst to convert them into hydrogen sulfide, and this is captured with zinc oxide. This method has problems such as requiring a hydrogen-containing gas and equipment to supply it, requiring high temperatures of 300 to 400°C, and complicated handling of the catalyst involved in the catalytic reaction. be. In addition, as a method for removing sulfur compounds from the gas produced by the reaction of carbonized coal gas, petroleum, or coal with steam and/or oxygen-containing gas, the gas is captured in hydrated iron oxide at room temperature, and oxidized at high temperature. Methods in which iron is used to capture hydrogen sulfide are known, but these methods mainly allow hydrogen sulfide to be captured, but there is a problem in that it is difficult to remove organic sulfur compounds. As a method for removing acidic sulfur compounds such as hydrogen sulfide from the gas generated by the reaction of petroleum or coal with steam and/or oxygen-containing gas, an alkali solution such as caustic potash or an amine compound such as monoethanolamine is used. Although a method of absorbing organic sulfur compounds into a solution of mercaptans is known, it is not suitable as a method for removing organic sulfur compounds such as mercaptans. A method using activated carbon as an adsorbent is known as a method for desulfurizing the various sulfur compound-containing gases mentioned above or for removing sulfur-containing odorous harmful components from those gases. Although it is effective in removing carbonyl, the current situation is that it is not satisfactory in removing organic sulfur compounds. British Patent No. 901609 discloses that sulfur-containing gas is first passed through a fixed bed of iron oxide or manganese oxide at a temperature around room temperature to remove only hydrogen sulfide, and then the sulfur-containing gas is passed through a fixed bed of iron oxide or manganese oxide at a temperature around room temperature to remove only hydrogen sulfide. A method is disclosed in which organic sulfur is removed by passing the oxide through a fluidized bed and performing oxidative regeneration at a temperature of, for example, about 700° C. before the sulfur content in the oxide exceeds 10%. However, there is no specific description of manganese oxide, nor is there any teaching about the use of amorphous manganese dioxide. Although it is taught that it is desirable to regenerate the oxide by high temperature oxidation, there is no teaching that the regeneration should be omitted. US Pat. No. 3,492,083 describes, for example, Na2:
A product obtained by reacting a mixture of NaOH, MgO and MnO ₂ with a molar ratio of Mg3:Mn1 at 400-500℃; with a molar ratio of Na1:Ca3:Mn1
Mixture of NaOH, CaO and _MnO2 at 500-800℃
The product obtained by the reaction; Na1:Mg3:
NaOH, MgO and Mn1 molar ratio
Product obtained by reacting a mixture of _MnO2 at 500-800℃; MgO with a molar ratio of MgO3:MnO2 ₁
After adsorbing and removing sulfur compounds in the gas using a product obtained by reacting a mixture of MnO ₂ and MnO 2 with 0.1 to 0.5 mol of V ₂ O ₅ at 800 to 900 °C, the adsorbent A method for regenerating is disclosed. However, US Pat. No. 3,492,083 does not teach the use of manganese dioxide-based adsorbents. JP-A No. 48-61360 discloses a method comprising contacting a reducing gas containing carbon dioxide and/or water vapor with a scavenger consisting of reduced manganese oxide, i.e. manganese suboxide, at a temperature of 100 to 600°C. Although a method for removing sulfur compounds from reducing gas is disclosed, a method using a desulfurizing agent made of manganese dioxide is not disclosed. JP-A No. 50-30795 describes manganese oxide,
A deodorizing catalyst composition containing a main catalyst component and an oxide of a transition metal element as a co-catalyst component is disclosed, and its action is simply to convert malodorous components such as sulfur compounds into odorless compounds. However, there is no teaching on how to capture and remove sulfur compounds from gas. In addition, although manganese dioxide, manganese sesquioxide, trimanganese tetroxide, etc. are exemplified as manganese oxides as the main catalyst component, not only is there no mention of using amorphous manganese dioxide, but It has been taught that manganese oxide alone has a short life and cannot be put to practical use. In addition, the catalyst composition is produced at a temperature of 600 to
High temperature treatment of 700℃ is required, and
It is only disclosed that it is used at a high temperature of 350°C. JP-A-55-1843 discloses a hydrogen sulfide remover whose main active ingredients are iron and manganese oxides, but the oxides mentioned here are obtained by decomposing iron and manganese salts. In the strict sense, oxides, oxyhydroxides,
It is a general term for hydroxides, etc., and the structure of the oxide is not specifically taught. JP-A No. 56-2830 discloses a method of oxidizing and decomposing malodorous gases by contacting them at a temperature of 200 to 500°C using a mixed catalyst containing at least zinc oxide or manganese oxide and allofene. Although a method for removing malodors and a catalyst used therein are disclosed, it is taught that catalysts containing only metal oxides are undesirable because the duration of malodorous gas removal is short. On the other hand, specifically amorphous manganese dioxide is also not taught. JP-A No. 56-5133 discloses a sulfur-based malodorous substance remover which is prepared by precipitating iron and manganese oxides prepared by a specific method and then granulating them into granules in the absence of a binder. A manufacturing method is disclosed, and the oxides mentioned here include oxyhydroxide,
It is a general term for oxides, hydroxides, etc., and it is stated that there are no particular limitations on their types and abundance ratios, and the specific structure of the oxides actually used among these oxides. is not taught. [Problems to be Solved by the Invention] The present invention aims to solve the problems remaining in the prior art regarding methods for removing sulfur compounds in gas. The present invention provides a method for removing sulfur compounds from gas that can extremely efficiently capture and remove sulfur compounds from gas containing sulfur compounds such as hydrogen sulfide, mercaptans, sulfides, and organic sulfur compounds. The object of the present invention is to provide a desulfurizing agent for use in the method. The present invention extremely efficiently captures and captures sulfur compounds in gases such as natural gas, city gas, LPG, naphtha, and various gases obtained by processing petroleum products such as natural gas, LPG, and naphtha, and coal. The object of the present invention is to provide a method for removing sulfur compounds from gas and a desulfurization agent used in the method. The present invention is applicable to the purification of raw material gas used in the production of fuel cells and hydrogen or synthetic raw material gas, the purification of generated gas produced from natural gas, petroleum, and coal, the deodorization of odoriferous gases such as city gas, etc. The object of the present invention is to provide a method for removing sulfur compounds from gas that can efficiently purify, deodorize, and render harmless gas containing sulfur compounds, and a desulfurization agent used in the method. [Means for Solving the Problems] The present invention provides a method for converting a gas containing at least one sulfur compound selected from the group consisting of hydrogen sulfide, mercaptans, sulfides, and other organic sulfur compounds into manganese sulfate, manganese sulfate, Substantially amorphous material obtained by reacting an oxidizing agent selected from sodium hypochlorite, potassium subzincate, sodium permanganate, and potassium permanganate with an aqueous solution of a manganese salt selected from manganese nitrate and manganese chloride. manganese dioxide; the main component is manganese dioxide, and other manganese oxides as well as copper, iron, cobalt, silver,
A composition containing at least one metal oxide selected from lanthanum and cerium as a minor component; or a binder and substantially amorphous manganese dioxide obtained by an electrolytic method using manganese sulfate as a raw material. The present invention provides a method for removing sulfur compounds from gas, which is characterized by contacting and capturing sulfur compounds with a desulfurizing agent, and a desulfurizing agent used in the method. That is, the present invention provides manganese oxide, such as manganese dioxide, low-valent manganese trioxide, manganese tetroxide, and manganese monoxide, which is manganese dioxide, for example, permanganese in an aqueous solution of a manganese salt such as manganese sulfate. Amorphous manganese dioxide obtained by the action of an oxidizing agent such as acid soda is extremely effective against not only hydrogen sulfide and carbonyl sulfide but also organic sulfur compounds in gases that preferably do not substantially contain oxygen gas. This was achieved by discovering that it is possible to capture and remove Here, whether the material is amorphous or crystalline can be determined by X-ray diffraction. That is, a diffraction pattern in which the intensity of X-rays scattered at a diffraction angle specific to manganese dioxide is sharp can be determined to be crystalline. On the other hand, those that do not exhibit such characteristics and have a broad tone and those that are not scattered can be determined to be composed of amorphous manganese dioxide. The sulfur compounds captured and removed by the method of the present invention include hydrogen sulfide, mercaptans such as methyl mercaptan, sulfides such as dimethyl sulfide, carbon disulfide, carbonyl sulfide, and other organic sulfur compounds such as thiophene. do. Gases containing sulfur compounds to be treated by the method of the present invention include, for example, natural gas, city gas,
Examples include LPG, naphtha, and various gases obtained by processing petroleum such as natural gas, LPG, and naphtha, and coal. The method of the present invention and the desulfurization agent of the present invention are applicable to the purification of raw material gas used in fuel cells and the production of hydrogen or synthetic raw material gas, the purification of product gas produced from natural gas, petroleum, and coal, and the refining of gas produced from natural gas, petroleum, and coal, city gas, etc. It is applied to efficiently deodorize odorous gases and purify, deodorize, and detoxify other gases. The manganese dioxide used in the desulfurization agent of the present invention is, for example, aqueous solution of manganese salt such as manganese sulfate, manganese nitrate, manganese chloride, sodium hypochlorite, potassium hypozinc salt, sodium permanganate, potassium permanganate, etc. Examples include amorphous materials obtained by the action of oxidizing agents. Alternatively, a desulfurizing agent containing mostly amorphous and partially crystalline manganese dioxide obtained by an electrolytic method using manganese sulfate as a raw material can also be used as the desulfurizing agent of the present invention. The desulfurization agent of the present invention is usually effective if it has a specific surface area of 20 m ² /g or more, preferably 50 m ² /g or more, and there is a tendency that the larger the specific surface area, the more sulfur compounds are captured. Among manganese oxides, those other than manganese dioxide, and even crystalline manganese dioxide, have a lower amount of sulfur compounds trapped than amorphous manganese dioxide. In addition to amorphous manganese dioxide as a main component, the desulfurization agent of the present invention can also contain other manganese oxides and optionally oxides of metals such as copper, iron, cobalt, silver, lanthanum, and cerium. It can be contained to the extent that it does not cause any damage. The desulfurizing agent of the present invention is preferably prepared by adding and mixing a binder to manganese dioxide as a main component, and forming a granular,
It is used by molding it into tablets, rods, etc. Examples of binders used in the desulfurization agent of the present invention include inorganic binders such as boehmite gel (AlOOH), water glass, colloidal silica, bentonite, and talc, as well as polyvinyl alcohol, polyvinyl acetate, crystalline cellulose, and ethylcellulose. , methylcellulose, carboxymethylcellulose,
Examples include organic binders such as wax, starch, and dextrin. The amount of binder used in the desulfurizing agent of the present invention is usually 2% to 30%, preferably 2% to the weight of the desulfurizing agent.
% to 20%, and if it is less than 2%, the strength of the desulfurizing agent will decrease, which is not preferable, and if it exceeds 30%, the performance of the desulfurizing agent will decrease, which is not preferable. In the method of the present invention, the temperature at which the sulfur compound-containing gas is brought into contact with and captured by the desulfurizing agent is practically preferably between room temperature and about 150°C, and at high temperatures exceeding about 150°C, the amount of sulfur compounds captured decreases. This is also not desirable. The desulfurization agent of the present invention can be prepared using conventionally known carriers such as alumina, silica, titania, activated carbon, activated clay,
It can be used by being supported on acid clay, silica, alumina, magnesia, etc. [Effects of the Invention] According to the present invention, firstly, sulfur compounds in gas containing sulfur compounds such as hydrogen sulfide, mercaptans, sulfides, and organic sulfur compounds can be extremely efficiently captured and removed. can. According to the present invention, secondly natural gas, city gas,
It is possible to extremely efficiently capture and remove sulfur compounds in gases such as LPG, naphtha, or various gases obtained by processing petroleum such as natural gas, LPG, naphtha, coal, etc. According to the present invention, the third aspect is the purification of raw material gas used in the production of fuel cells and hydrogen or synthetic raw material gas, the purification of generated gas produced from natural gas, petroleum, and coal, and the purification of odorized city gas etc. It is possible to efficiently deodorize gas, purify/deodorize gas containing other sulfur compounds, and render it harmless. [Example] The present invention will be explained in more detail using the following example. Example 1 Sulfuric acid was added to 395 g of manganous sulfate/aqueous solution 1 to prepare an aqueous solution of manganese sulfate with pH=1. Add potassium permanganate to this solution.
After adding 278.6g and oxidizing, water was added to this slurry while keeping the temperature around 50℃, and 30
Aged for a minute. When this was washed with water and dried at 110°C, 340 g of manganese dioxide was obtained. As a result of X-ray analysis of this manganese dioxide, it was confirmed that it was not crystalline. Also XPS (X-ray photoelectron spectroscopy)
Analysis was performed, and the binding energy value of the Mn2P3/2 peak confirmed that it was manganese dioxide. 34.6 g of bentonite was mixed with 300 g of this manganese dioxide, an appropriate amount of water was added, and the mixture was kneaded with a kneader. The resulting mixture is
It was dried at 110° C. for 5 hours and pulverized into 8 to 16 meshes to obtain a desulfurizing agent-A having a specific surface area of 240 m ² /g. This desulfurizing agent - A40c.c. (32g in weight) is filled into a cylindrical container, and this filled container contains approximately 90% methane, as well as ethane, propane and butane, as well as organic sulfur compounds such as t- A test was conducted in which a gas containing 2 ppmV of butyl mercaptan and 2 ppmV of dimethyl sulfide was flowed at a rate of 0.34 Nm ³ /Hr under conditions of GHSV 7500 Hr ^-1 at room temperature and normal pressure. The content of sulfur compounds in the gas exiting the desulfurizing agent-filled container was analyzed using an FPD gas chromatograph. The first thing to break through was dimethyl sulfide, and even if 100% dimethyl sulfide leaked, t-butyl mercaptan was still below the detection limit of the FPD gas chromatograph, that is, below 0.2 ppmV. Breakthrough here means that the concentration of sulfur compounds in the gas exiting the desulfurizing agent filled container reaches a certain level, in other words, it reaches 0.2 ppmV, which is the detection limit of the FPD gas chromatograph. The breakthrough time is defined as the elapsed time until the concentration of dimethyl sulfide reaches 0.2 ppmV, and the results are shown in Table 1. The amount of sulfur in the trapped sulfur compounds is expressed as a percentage (%) of the weight of the desulfurizing agent, and is defined as the trapped amount, and the results are shown in Table 1. In addition, from the analysis of the total sulfur concentration in the gas emitted from the desulfurization agent-filled container until breakthrough by the Witskbold method and the analysis results of the total sulfur concentration of the desulfurization agent after breakthrough, it is clear that the sulfur compounds in the gas are captured by the desulfurization agent. I have confirmed that it has been removed. Example 2 An experiment similar to Example 1 was conducted using desulfurizing agent A, except that nitrogen gas containing 100 ppmV of dimethyl sulfide was used. The results obtained are shown in Table 1. Example 3 An experiment similar to Example 1 was conducted using desulfurization agent A, except that methane gas containing 100 ppmV of dimethyl sulfide was used. The results obtained are shown in Table 1. Example 4 An experiment similar to Example 3 was conducted using desulfurizing agent A except that the temperature of the desulfurizing agent was 70°C. The results obtained are shown in Table 1. Example 5 An experiment similar to Example 2 was conducted using desulfurizing agent A except that the temperature of the desulfurizing agent was 150°C. The results obtained are shown in Table 1. In addition, it has been confirmed that the sulfur compounds in the gas are captured and removed by the desulfurization agent based on the results of analyzing the total sulfur concentration in the gas emitted from the desulfurization agent-filled container until breakthrough using the Wickbold method. Example 6 An experiment similar to Example 1 was conducted using desulfurization agent A, except that nitrogen gas containing 100 ppmV of methyl mercaptan was used. The results obtained are shown in Table 1. Example 7 An experiment similar to Example 1 was conducted using desulfurizing agent A, except that nitrogen gas containing 100 ppmV of hydrogen sulfide was used. The results obtained are shown in Table 1. Example 8 188 g of copper nitrate/10 of an aqueous solution and 106 g of sodium carbonate/10 of an aqueous solution were mixed at 40°C, and the resulting precipitate was washed with water and dried to obtain 750 g of copper oxide. 95 g of copper oxide thus obtained, 380 g of manganese dioxide used in Example 1, and 25 g of bentonite.
g were mixed, an appropriate amount of water was added, and the mixture was kneaded using a kneader. The resulting mixture was dried at 120°C for 5 hours and ground into 8 to 16 meshes, with a specific surface area of 220
Desulfurizing agent-B having a m ² /g was obtained. A test was conducted under the same conditions as in Example 1 using the obtained desulfurizing agent-B (26 g in weight). The results obtained are shown in Table 1. Example 9 475 g of manganese dioxide obtained by electrolytic method using manganese sulfate as a raw material and 25 g of bentonite were mixed, an appropriate amount of water was added, and the mixture was kneaded in a kneader. The resulting mixture was dried at 120° C. for 5 hours and ground into 8 to 16 meshes to obtain desulfurizing agent C.
The specific surface area of this desulfurizing agent C was 58 m ² /g, and the diffraction pattern in X-ray analysis was broad, and it was confirmed that it was mainly composed of amorphous manganese dioxide. A test was conducted under the same conditions as in Example 1 using the obtained desulfurizing agent C (56 g in weight). The results obtained are shown in Table 1. Comparative Example 1 Manganese sulfate (172 g/aqueous solution 10) and ammonia water (136 g/aqueous solution 10) were mixed at room temperature, and the resulting precipitate was washed with water to obtain manganese hydroxide. The manganese hydroxide precipitate thus obtained was oxidized by exposing it to a stream of air at room temperature for one day and night. As a result of X-ray analysis of this precipitate, crystalline dimanganese trioxide was identified, and according to XPS analysis, manganese dioxide was not identified. 350g of this manganese trioxide and bentonite
52 g were mixed, an appropriate amount of water was added, and the mixture was kneaded using a kneader. The resulting mixture was dried at 120° C. for 5 hours and ground into 8 to 16 meshes to obtain desulfurizing agent D. Using this desulfurizing agent D (weight: 40 g), a test was conducted under the same conditions as in Example 2. The results are shown in Table 1. Comparative Example 2 An aqueous solution 10 containing 172 g of manganese sulfate and 10 aqueous solution containing 136 g/aqueous ammonia were mixed at room temperature to obtain a solution containing precipitates of manganese hydroxide. After adding 300 g of sodium hypochlorite containing 10% available chlorine to this solution and oxidizing it, the precipitate was filtered, washed with water, and dried. As a result of X-ray analysis of this precipitate, crystalline dimanganese trioxide was identified, and according to XPS analysis, manganese dioxide was not identified. Furthermore, 350g of this precipitate contains 52% bentonite.
g were mixed, an appropriate amount of water was added, and the mixture was kneaded using a kneader. The resulting mixture was dried at 120°C for 5 hours,
Desulfurization agent-E was obtained by grinding into 8 to 16 meshes. A test was conducted under the same conditions as in Example 2 using the obtained desulfurizing agent E (weight: 34 g). The results are shown in Table 1. Comparative Example 3 Manganese nitrate was thermally decomposed at 200℃ in an oxygen stream,
Manganese oxide was prepared. As a result of X-ray analysis of this manganese oxide, crystalline manganese dioxide was identified. 475g of this manganese dioxide and 25g of bentonite
Then, an appropriate amount of water was added and kneaded using a kneader. The resulting mixture was dried at 120°C for 5 hours, pulverized into 8 to 16 mesh sizes, and desulfurizing agent F was added.
I got it. The performance of desulfurization agent F (65g in weight),
The test was conducted under the same conditions as in Example 2. The results are shown in Table 1. Comparative Example 4 Breakthrough time and trapped amount were measured in the same manner as in Example 1 using desulfurizing agent G (19 g in weight) prepared by adding bromine to commercially available activated carbon (particle size 4 to 8 mesh). The results obtained are shown in Table 1. 【table】

Claims (1)

[Scope of Claims] 1. A gas containing at least one sulfur compound selected from the group consisting of hydrogen sulfide, mercaptans, sulfides, and other organic sulfur compounds, from manganese sulfate, manganese nitrate, and manganese chloride. Substantially amorphous manganese dioxide obtained by treating an aqueous solution of a selected manganese salt with an oxidizing agent selected from sodium hypochlorite, potassium hypochlorite, sodium permanganate and potassium permanganate; A composition containing manganese as a main component and at least one oxide of a metal selected from other manganese oxides and copper, iron, cobalt, silver, lanthanum, and cerium as a minor component;
Alternatively, a method for removing sulfur compounds in a gas, which is characterized by contacting and capturing a desulfurizing agent consisting of a binder and substantially amorphous manganese dioxide obtained by an electrolytic method using manganese sulfate as a raw material. 2. A desulfurizing agent used in the method according to claim 1.