JP3103212B2 - Adsorbent for sulfur compounds - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an adsorbent for a sulfur compound in exhaust gas. More specifically, when the concentration of the sulfur compound contained in the exhaust gas is low, these are adsorbed,
It relates to an adsorbent used for removal.

[0002]

2. Description of the Related Art Exhaust gas having a low sulfur compound concentration, such as exhaust gas discharged from poultry farms, human waste treatment plants or sewage treatment plants, ventilation gas from road tunnels, and exhaust gas from combustors used in homes, etc. Contains 0.1 to several ppm of sulfur compounds, causing odor and causing pollution. Furthermore, the exhaust gas containing sulfur compounds generated from these sources often has a normal temperature at room temperature, and often has an enormous amount of exhaust gas. In these respects, the conventional exhaust gas purification and removal methods are used. It is difficult to remove exhaust gas efficiently by the method.

As a method for removing sulfur compounds from the exhaust gas, there is a method for removing by adsorption.
No. 60, but several tens of pp
The concentration is from m to several thousand ppm, and the adsorbing ability is reduced for a sulfur compound of 0.1 to several ppm. In addition, Tokubo Sho 5
JP-A-5-37946, JP-B-56-4301,
Japanese Patent Publication No. 56-10096 discloses an adsorbent for a sulfur compound of 1 ppm or less, but has insufficient durability.

[0004]

DISCLOSURE OF THE INVENTION The present invention contains a sulfur compound in exhaust gas, the temperature of which is ordinary temperature, and the amount of exhaust gas is enormous. An object of the present invention is to provide an adsorbent that has excellent adsorption ability for sulfur compounds contained in exhaust gas and has high adsorption ability for a long period of time when removal is difficult.

[0005]

Means for Solving the Problems The present inventors have made intensive studies to achieve the above object, and as a result, (1) aluminum, titanium, silicon and At least one oxide selected from zirconium is 30 to 90% by weight, and manganese oxide is 10 to 70% by weight, (2) its specific surface area is 30 m ² / g or more, and (3) its total pores are 0 of us.
The pores in the range of 2 μm to 4 μm are 10 to 10% of the total pore volume.
40%, and pores in the range of 0.2 μm to 4 μm have a pore size of 0.0%.
The present inventors have found that an adsorbent characterized by having a pore volume of 5 cc / g or more can achieve the above object, and have completed the present invention. Hereinafter, the present invention will be described in more detail.

The sulfur compound adsorbent of the present invention comprises (A) 30 to 90% by weight of at least one oxide selected from the group consisting of aluminum, titanium, silicon and zirconium, and (B) 10 to 70% of manganese oxide. % Of the component (A) is 30 to 90% by weight, preferably 30 to 60% by weight, and the ratio of the manganese oxide as the component (B) is 10 to 70% by weight. % By weight, preferably 40 to 70% by weight. If the proportion of this component (A) is less than 30% by weight, the surface area is reduced and the strength of the adsorbent is also weakened, making it difficult to withstand practical use.
Exceeding 0% by weight is not preferred because the ability to adsorb sulfur compounds is reduced.

Among the starting materials of the component (A), the oxides of aluminum, titanium and zirconium are not particularly limited, but are preferably oxides, nitrates, chlorides and sulfates thereof. 1 selected from organic compounds such as inorganic salts and oxalates and acetates.
Species or two or more compounds are used, more preferably inorganic salts such as nitrates, chlorides and sulfates. Silicon is not particularly limited, but is preferably an oxide or a colloidal compound. One or more compounds selected from silica, fine particle silicic acid, water glass, inorganic silicon compounds such as silicon tetrachloride, and organosilicon compounds such as tetrasilicate are used, and colloidal silica is more preferable.

When the component (A) is used as an oxide,
To illustrate a method for producing the oxide, the above compound is
The concentration of each oxide was converted to a concentration of 1 to 100 g / liter and maintained at 10 to 100 ° C., and aqueous ammonia was added dropwise thereto as a neutralizing agent under stirring to produce a compound containing each metal. Separate and wash well after 80 ~ 14
Dry at 0 ° C for 1 to 10 hours, then 450-700 ° C
Then, by firing for 1 to 10 hours, a target metal oxide can be obtained.

The starting material of the manganese oxide of the component (B) is not particularly limited, but is preferably an oxide, a hydroxide, an ammonium salt, an oxalate, a carbonate, an acetate, or a halide. Etc. can be appropriately selected and used.

The method for preparing the sulfur compound adsorbent of the present invention is not particularly limited, and can be prepared by various methods. A typical preparation method will be described below.

(1) To the aqueous solution of the starting material of the component (B),
Add the molding aid and the powder that is the starting material for component (A),
A method of mixing, kneading, and forming into a honeycomb shape or a pellet shape by an extrusion molding machine. (2) A molding aid is added to an aqueous solution of the starting materials of the components (A) and (B), mixed and dried until a moldable state is obtained, and the mixture is extruded into a honeycomb shape or a pellet shape by an extruder. how to. (3) A powder of the starting material of the component (B) and a forming aid are added to an aqueous solution of the starting material of the component (A), mixed, kneaded, and formed into a honeycomb or pellet by an extruder. After drying the obtained molded product at 50 to 120 ° C, 300 to 700 ° C, preferably 350 to 650 ° C
For 1 to 10 hours, preferably 2 to 6 hours, to obtain the sulfur compound adsorbent according to the present invention.

Examples of the molding aid include organic binders such as polyvinyl alcohol, glycerin, and cellulose, and inorganic binders such as alumina sol and silica sol, and are preferably organic binders.

In the above method, the specific surface area is not less than 30 m ² / g and 0.2 μm to 4 μm of all the pores.
10 to 40% of the total pore volume and 0.1 to 40% of the total pore volume.
A sulfur adsorbent having a pore volume of at least 05 cc / g can be prepared. Hereinafter, a preferred method for preparing an adsorbent having such characteristics will be described.

(1) A method of appropriately adjusting the particle size of the powder of the starting material, (2) Addition of a resin which volatilizes and decomposes in the firing step during molding, an organic polymer such as cellulose, and an inorganic salt such as ammonium nitrate. Method.

The average particle diameter of the starting material powder in the method (1) is usually 5 to 30 μm. 5 μm
If it is less than 30, it is not possible to prepare an adsorbent having the intended pore distribution, and if it exceeds 30 μm, the moldability is poor and it is suitable.

Typical examples of the organic polymer which can be used in the method (2) include polyethylene resin, acrylic resin,
Crystalline cellulose and the like can be mentioned. Typical examples of the inorganic salts include ammonium nitrate, ammonium oxalate, and ammonium carbonate. The amount of these additives is 5 to the raw material powder.
The range is preferably from 30 to 30% by weight.

In the sulfur compound adsorbent obtained by these methods, the pore volume having a pore diameter in the range of 0.2 μm to 4 μm is 10 to 40% of the total pore volume, and the pore volume is 0%. In addition to having not less than 0.05 cc / g, as shown in FIG. 1 (the catalyst of Example 1 according to the present invention), a very sharp pore size distribution having a pore size in a range of 0.2 μm to 4 μm is obtained. The points shown are characteristic. Having this extremely sharp pore diameter distribution and being within a specific pore diameter range means that the sulfur compound adsorbent of the present invention is composed of pores having an extremely uniform pore diameter. It is considered to be a cause of showing excellent adsorption ability to sulfur compounds at normal temperature and low concentration.

That is, although the cause is not clear, since the temperature is normal temperature when the gas diffuses into the pores of the adsorbent, the pore group having a uniform pore diameter as in the present invention is used. It is considered that the gas easily diffuses in the pores of the gas, and as a result, even if the sulfur compound has a low concentration, the adsorption ability is improved and the durability is excellent.

The specific surface area can be determined by a usual method, for example,
The pore volume is measured by a BET method, and the pore volume is measured by a usual method, for example, a mercury intrusion method.

Further, the pore volume having a pore diameter in the range of 0.2 μm to 4 μm is 10 to 40% of the total pore volume, and the pore volume is 0.05 cc / g or more. A pore volume having a pore diameter in this range is less than 10% of the total pore volume,
Alternatively, if the pore volume in this range is less than 0.05 cc / g, the ability to adsorb the sulfur compound is reduced, and if the pore volume in this range exceeds 40%, the mechanical strength of the adsorbent itself is reduced, resulting in practical use. It will not be.

The total pore volume of the adsorbent is 0.3 cc /
It is preferably in the range of g to 0.6 cc / g.

The gas that can be treated by the adsorbent of the present invention is not particularly limited as long as it contains a sulfur compound. Examples of the gas include exhaust gas discharged from a poultry farm, human waste treatment plant, sewage treatment plant and road. It can be used for ventilation gas and the like discharged from a tunnel, and is particularly effective for adsorption and removal of gas having a low sulfur compound concentration.

The gas having a low sulfur compound concentration is as follows.
Specifically, the sulfur compound concentration is 0.01 to 100 pp.
m, and this gas may contain about 10 to 20% by volume of oxygen, 1 to 15% by volume of carbon dioxide, and steam may contain about saturated steam.

Although the processing conditions vary depending on the type and properties of the exhaust gas, the temperature is usually room temperature (5 ° C. to 35 ° C.).
° C.), the space velocity is 1000~100000hr ~ ^1, in particular in the range of 3000~30000hr ~ ¹ is preferred.

[0025]

The main effects of the present invention are as follows.

(1) By using the adsorbent of the present invention, low concentration sulfur compounds can be efficiently adsorbed and removed at room temperature.

(2) The adsorbent of the present invention can efficiently adsorb and remove low-concentration sulfur compounds in exhaust gas in which moisture coexists.

(3) The adsorbent of the present invention has excellent durability,
It can adsorb and remove low-concentration sulfur compounds in exhaust gas over a long period of time.

[0029]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples.

(Example 1) (Preparation of component A) Aluminum nitrate (Al (NO ₃ ) _3.
9H ₂ O) in 472 g of ammonia water (NH ₃ 25% by weight)
283 g was added to obtain a gel. The gel was filtered, washed with water, and dried at 200 ° C. for 10 hours. Then 600 ° C
For 6 hours in an air atmosphere, further pulverized using a hammer mill, and classified using a classifier to obtain a powder having an average particle diameter of 15 μm.

(Preparation of Adsorbent) Powder 20 obtained above
0 g and 264 g of manganese carbonate (MnCO ₃ ) are kneaded with a kneader while adding an appropriate amount of water, kneaded well, and then 5 mmφ.
It was molded into a pellet of (diameter) × 5 mmL (length).

Then, after drying at 60 ° C.,
It was calcined under air flow for hours. The composition of the obtained adsorbent is
Al ₂ O ₃ —MnO ₂ = 50: 50 by weight ratio as oxide (manganese oxide as manganese dioxide).

The pore volume having a pore size in the range of 0.2 to 4 μm was 0.13 cc / g. Further, the pore size distribution of the obtained adsorbent was measured by a mercury intrusion porosimeter (manufactured by Shimadzu Corporation), and the results are shown in FIG.

(Evaluation of performance of adsorbent) 15 cc of this adsorbent
Was charged into a cylindrical reactor having an inner diameter of 30 mmφ, and a simulated gas shown below was supplied at 6 Nl / min, and the sulfur compound removal rate was measured.

The measurement of SO ₂ is carried out by the infrared absorption method using H ₂ S
And mercaptan are gas chromatograph (column TPE
Concentration method). H ₂ S,
Each mercaptan and SO ₂ is 1 ppm, the remainder was used gas such that a relative humidity of 80% air. Also,
The removal rate of the sulfur compound was calculated by the following equation. Table 1 shows the removal ratio of each component.

[0036]

(Equation 1)

(Examples 2 and 3 and Comparative Examples 1 and 2) An adsorbent was prepared in the same manner as in Example 1 except that the content of manganese oxide was changed to prepare an adsorbent. Table 1 shows the composition of the adsorbent and the sulfur compound removal rate.

(Examples 4, 5 and 6) In Example 1, an aqueous solution of titanyl sulfate in sulfuric acid (Example 4) was used as a titanium source, and Snowtex NCS-30 was used as a silicon source.
(Nissan Chemical Co., Ltd. silica sol) (Example 5), zirconium nitrate Zr (NO ₃₎ as the zirconium source ₄ & 5
The adsorbent was prepared in the same manner as in Example 1 except that the adsorbent was prepared using H ₂ O (Example 6). The adsorbent was evaluated. The composition and the sulfur compound removal rate are shown in Table 1.

Comparative Example 3 An adsorbent was prepared in the same manner as in Example 1 except that a powder having an average particle diameter of 1 μm was used instead of the powder having an average particle diameter of 15 μm. The results were evaluated and the results are shown in Table 1. The pore volume of this adsorbent having a pore diameter in the range of 0.2 to 4 μm is 0.01
cc / g. FIG. 2 shows the pore distribution of the obtained adsorbent.

As can be seen from FIGS. 1 and 2, even if the pore diameter shows a sharp distribution, if the distribution range is not in the range of 0.2 μm to 4 μm, the adsorption power is low. is there. Although there are many pores as small as 0.1 μm or less, a portion in this range is removed from FIGS. 1 and 2 for convenience.

[0041]

[Table 1]

[Brief description of the drawings]

FIG. 1 is a diagram of a measurement result of a pore distribution of a catalyst according to Example 1, in which a pore volume with respect to a pore diameter is plotted and is shown by both an integral type and a differential type.

FIG. 2 is a diagram of a measurement result of a pore distribution of a catalyst according to Comparative Example 3, in which a pore volume with respect to a pore diameter is plotted, and is shown by both an integral type and a differential type.

────────────────────────────────────────────────── ─── Continuation of the front page Examiner Shigehiro Toyonaga (56) References JP-A-49-22390 (JP, A) JP-A-51-35686 (JP, A) JP-A-48-29478 (JP, B1) 48-20102 (JP, B1) (58) Fields investigated (Int. Cl. ⁷ , DB name) B01J 20/00-20/34 B01D 53/46

Claims (1)

(57) [Claims] (1) At least one selected from the group consisting of aluminum, titanium, silicon and zirconium
30 to 90% by weight of the seed oxide and 1% of manganese oxide
(2) having a specific surface area of 30% by weight.
m ² / g or more, (3) 0.2 μm or more of all the pores
Pores in the range of 4 μm are 10 to 40% of the total pore volume,
And the pore size in the range of 0.2 μm to 4 μm is 0.05 cc /
An adsorbent for a sulfur compound in exhaust gas, which has a pore volume of at least g.