JP3230864B2 - Method for producing desulfurizing agent - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a desulfurizing agent. More specifically, the present invention relates to a method for producing a desulfurizing agent used for desulfurizing various gases and oils.

[0002]

2. Description of the Related Art It has been known that copper has excellent performance as a desulfurizing agent, and it is usually used while being held on a carrier such as activated carbon, alumina and zinc oxide. However, since the known copper-based desulfurizing agent has a low sulfur adsorption capacity, it needs to be used in a large amount in order to continue the desulfurization for a long time, and also stabilizes the desulfurization to a low level of 1 ppb or less. It was difficult to do. Also, JP-A-1-123627, JP-A-1-123627
JP-A-123628 and JP-A-2-302496 disclose copper-zinc-based and copper-zinc-based compounds prepared by a coprecipitation method.
A desulfurizing agent capable of reducing the sulfur content in various gases and oils to a level of 0.1 ppb by hydrogen reduction of an aluminum-based mixture is described. Although the desulfurizing agent obtained by this method has a sufficient life compared to other copper-based desulfurizing agents, it must have a more stable and longer life when used in an actual process. Is required.

[0003]

SUMMARY OF THE INVENTION The present inventor has conducted various studies in view of the above-mentioned problems with the copper-based desulfurizing agent, and as a result, has found that copper hydroxide, zinc compound and aluminum hydroxide are used as the aluminum source. The mixture is mixed with an aqueous solution of an alkaline substance to form a precipitate, and a desulfurizing agent obtained by hydrogen-reducing a copper oxide-zinc oxide-aluminum oxide mixture prepared by washing, drying and calcining the precipitate with water is used. By doing so, it has been found that the sulfur content in various gases and oils can be reduced to a level of 0.1 ppb or less over a long period of time. That is, copper-zinc-
It has been clarified that the use of aluminum hydroxide as an aluminum source when preparing an aluminum-based desulfurizing agent can significantly improve the desulfurization performance. The present invention has been made based on such findings, and has as its object to provide a method for producing a desulfurizing agent having high desulfurization performance.

[0004]

Means for Solving the Problems A method for producing a desulfurizing agent according to the present invention, which has been made to solve the above-mentioned problems, uses a copper compound, a zinc compound and aluminum hydroxide, and mixes the mixture with an aqueous solution of an alkaline substance. To form a precipitate, and the resulting precipitate is washed, dried, and calcined to reduce the mixture of copper oxide, zinc oxide, and aluminum oxide with hydrogen. Hereinafter, the method of the present invention will be described in detail.

The method for producing a copper-zinc-aluminum desulfurizing agent in the present invention is carried out, for example, by the following method. Copper compounds (eg, copper nitrate, copper acetate, etc.) and zinc compounds (eg, zinc nitrate, zinc acetate, etc.)
A solution in which aluminum hydroxide is added to an aqueous solution containing the above is dropped into an aqueous solution of an alkaline substance (eg, sodium carbonate, potassium carbonate, etc.) maintained at a temperature of about 60 ° C. while stirring to form a precipitate. At this time, the order of adding the solution for generating the precipitate may be reversed, and the solution of the copper, zinc and aluminum compounds may be added to the solution of the alkaline substance. Alternatively, aluminum hydroxide may be added to a solution of an alkali substance, and this solution may be mixed with an aqueous solution containing a copper compound and a zinc compound to form a precipitate. Then
The precipitate formed is thoroughly washed with water, filtered and dried. Next, this is calcined at about 270 to 400 ° C., and once slurried with water, filtered and dried to obtain copper oxide-zinc oxide-
A sintered body of aluminum oxide is obtained. The obtained sintered body is
After adding an auxiliary agent (for example, graphite or the like) as necessary, the mixture is formed into, for example, a tablet or an extruded product.

The compounding ratio of copper oxide, zinc oxide and aluminum oxide in the above sintered body is usually copper: zinc: aluminum = 1: about 0.3-10: about 0.05-
2, more preferably 1: about 0.6-3: about 0.3-1. If the amount of zinc is too small, sintering of copper cannot be effectively prevented, while if the amount of zinc is too large, sufficient desulfurization performance as a copper-based desulfurizing agent will not be exhibited. If the amount of aluminum is too small, the Cu—ZnO structure cannot be stabilized, while if the amount of aluminum is too large, the desulfurization performance decreases. The copper-zinc- thus obtained
The aluminum-based mixed oxide may contain a certain metal compound such as chromium oxide as another carrier component. Next, the mixed oxide obtained above is subjected to hydrogen reduction. In hydrogen reduction, since copper has a low melting point, the particle size increases due to heat, the surface area tends to decrease due to heat, and the pore structure is slightly changed due to excessive heat, and as a result, the properties as a desulfurizing agent are reduced. It changes greatly. Therefore, in the hydrogen reduction of the mixed oxide, it is preferable that the hydrogen reduction of copper oxide, which is an exothermic reaction, is allowed to proceed under mild conditions,
For example, the hydrogen content is 6% or less, more preferably 0.5 to
In the presence of hydrogen gas diluted with a gas that does not participate in the reaction (for example, nitrogen gas, argon gas, methane gas, or the like) so as to be about 4% by volume, the reduction treatment is performed while maintaining the temperature at about 150 to 350 ° C. Is preferred. In particular, an inert gas such as a nitrogen gas is preferably used as a gas that does not participate in the reaction.

[0007] The copper-zinc-aluminum desulfurizing agent obtained by the above method has a dense structure composed of aggregates of fine particles, and extremely small copper fine particles are uniformly dispersed on the surface of zinc oxide particles. At the same time, it is in a highly active state due to chemical interaction with zinc oxide. On the other hand, aluminum oxide is distributed throughout, and maintains a highly active state by preventing sintering of copper particles and zinc oxide particles due to heat. Therefore, when using these desulfurizing agents, ensure that the sulfur content in various gases and oils is 5 ppb or less, 1 ppb or less under normal conditions, and 0.1 ppb or less easily under appropriate conditions. Can be.

The copper-zinc compound of the present invention thus prepared
The aluminum-based desulfurizing agent is used for desulfurizing various gases and oils, and is preferably used in a temperature range of 150 to 400 ° C. More specifically, in the same manner as a known desulfurizing agent, for example, a gas or oil to be purified is charged into an adsorption desulfurization device having a predetermined shape, and the gas or oil to be purified is charged into the GHSV200.
Used by passing at 通過 4000 h ⁻¹ .
Since the desulfurizing agent of the present invention has a high desulfurization performance that cannot be refined by a conventional desulfurizing agent, when the sulfur concentration in the gas or oil to be refined is high (for example, several tens pp
m or more) has a particularly remarkable effect when used as a secondary desulfurizing agent, which performs desulfurization as much as possible by primary desulfurization using a zinc oxide desulfurizing agent or the like according to a conventional method, and then performs a higher degree of desulfurization. . When the sulfur concentration in the gas or oil to be purified is low (for example, several ppm or less), the desulfurizing agent of the present invention alone exhibits sufficient desulfurization performance. Examples of the gas or oil to be purified include natural gas, ethane, propane, butane, LPG (liquefied natural gas), light naphtha, heavy naphtha, kerosene, coke oven gas, various city gases, and the like. You.

[0009]

According to the present invention, a copper-zinc-aluminum desulfurizing agent having extremely excellent desulfurizing performance can be obtained, and various gases and oils highly desulfurized with a small amount of desulfurizing agent can be used. There is an effect that it can be easily obtained with stability over time. Therefore, when a catalyst which is weak against sulfur poisoning is used, it is possible to practically completely prevent sulfur poisoning, and it is possible to eliminate the adverse effects of sulfur to an extremely high level. Further, aluminum hydroxide is used as an aluminum source, so that desulfurization performance is improved and a desulfurizing agent can be produced at lower cost than when other aluminum compounds are used.

[0010]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Reference Examples and Examples, but the present invention is not limited to these Examples. Reference Example 1 A coke oven gas having a sulfur content of 200 ppm (weight concentration as sulfur, the same applies hereinafter) was first prepared by a conventional method using Ni.
-A temperature of 380 ° C and a pressure of 8 in the presence of a Mo-based hydrodesulfurization catalyst.
kg / cm ² · G, GHSV (Gas Hourly Space Velocity) 10
After hydrocracking under the conditions of 00, the mixture was contacted with a ZnO-based adsorptive desulfurizer to desulfurize it. The sulfur compound content in the obtained purified gas was about 0.1 ppm.

Example 1 Copper nitrate, zinc nitrate and aluminum hydroxide were mixed at a molar ratio of 1:
A mixed aqueous solution containing at a ratio of 1: 0.3 is added dropwise to an aqueous solution of sodium carbonate maintained at about 60 ° C. while stirring to form a precipitate. The precipitate is thoroughly washed with water, then filtered and dried. Next, this was baked at about 350 ° C., once formed into a slurry with water, filtered and dried, and a forming agent was added to form a 1/8 inch diameter × 1/8 inch length. Next, about 100 cc of the fired body was charged in a secondary desulfurization apparatus, and nitrogen gas containing 2% by volume of hydrogen was passed through the apparatus to reduce the temperature at 200 ° C. to obtain a desulfurizing agent. Using the desulfurizing agent, the purified gas 400 (l / h) obtained in Reference Example 1 was subjected to secondary desulfurization at a temperature of 350 ° C. and a pressure of 8 kg / cm ² · G. as a result,
The sulfur compound content in the finally obtained purified gas is 1
The level was below 0.1 ppb on average over 5000 hours of operation.

Reference Example 2 LPG having a sulfur content of 20 ppm was first prepared by a conventional method at a temperature of 380 in the presence of a Ni—Mo hydrodesulfurization catalyst.
° C, pressure 10kg / cm ² · G, LHSV (Liquid Hourly space
After hydrogenolysis under the conditions of (Velocity) 1.0 and hydrogen / naphtha = 0.1 (molar ratio), desulfurization was performed by contacting with a ZnO-based adsorptive desulfurizing agent. The sulfur compound content in the obtained purified gas was about 0.05 ppm.

Example 2 100 cc of a copper-zinc-aluminum fired body obtained by the same production method as in Example 1 was charged into a secondary desulfurization apparatus, and a nitrogen gas containing 2% by volume of hydrogen was passed therethrough. It was reduced at ℃ to obtain a desulfurizing agent. Using the desulfurizing agent, the purified gas 400 (l / h) obtained in Reference Example 2 was subjected to secondary desulfurization at a temperature of 350 ° C and a pressure of 8 kg / cm ² · G. as a result,
The sulfur compound content in the finally obtained purified gas is 8
The average level was below 0.1 ppb over 000 hours of operation.

Example 3 Aluminum hydroxide is dissolved in an aqueous solution of sodium hydroxide at about 120 ° C. and stirred until an aluminate is formed. This sodium aluminate solution is added to the sodium carbonate solution and the solution is kept at about 60 ° C. A mixed aqueous solution containing copper nitrate and zinc nitrate at a molar ratio of 1: 1 is gradually added dropwise to this solution while stirring to form a precipitate. Subsequent treatment was performed in the same manner as in Example 1, and the molar ratio was 1: 1: 0.0.
A sintered body of copper oxide-zinc oxide-aluminum oxide No. 3 was obtained. Next, 100 cc of the fired body was filled in a secondary desulfurization apparatus, and a nitrogen gas containing 2% by volume of hydrogen was passed therethrough.
Reduction was performed at 00 ° C. to obtain a desulfurizing agent. Using the desulfurizing agent, the purified gas 400 (l / h) obtained in Reference Example 2 was heated at a temperature of 3
It was subjected to secondary desulfurization under the conditions of 50 ° C and a pressure of 8 kg / cm ² · G.
As a result, the sulfur compound content in the finally obtained purified gas was 0.1 ppb on average over 8000 hours of operation.
The levels were as follows:

Example 4 Aluminum hydroxide was added to an aqueous solution of sodium carbonate, the solution was kept at 60 ° C., and a mixed aqueous solution containing copper nitrate and zinc nitrate in a molar ratio of 1: 1 was gradually added thereto while stirring. To form a precipitate. Subsequent processing was performed in the same manner as in Example 1 to obtain a copper oxide-zinc oxide-aluminum oxide sintered body at a molar ratio of 1: 1: 0.3. Next, 100 cc of the fired body was charged into a secondary desulfurization apparatus, and nitrogen gas containing 2% by volume of hydrogen was passed therethrough, and reduced at a temperature of 200 ° C. to obtain a desulfurizing agent. Using the desulfurizing agent, the purified gas 400 (l / h) obtained in Reference Example 2 was heated at a temperature of 350 ° C.
It was subjected to secondary desulfurization under the conditions of a pressure of 8 kg / cm ² · G. As a result, the sulfur compound content in the finally obtained purified gas was 0.1 ppb or less on average over 8000 hours of operation.

Example 5 Aluminum hydroxide is dissolved in an aqueous solution of sodium hydroxide at about 120 ° C. and stirred until an aluminate is formed. This sodium aluminate solution is added to the sodium carbonate solution and the solution is kept at about 60 ° C. To this solution, a mixed aqueous solution containing copper nitrate and zinc nitrate at a molar ratio of 1: 1 is gradually added dropwise with stirring to produce a precipitate. The precipitate is thoroughly washed with water, filtered and dried. Then this is about 28
After baking at 0 ° C., once slurried with water, filtered, dried, pressed into a tablet having a diameter of ８ inch and a length of ８ inch, copper oxide having a molar ratio of 1: 1: 0.3 -A sintered body of zinc oxide-aluminum oxide was obtained. Then, the fired body is about 150
hydrogen in a desulfurization tube (desulfurization layer length 30 cm) filled with cc
After reducing nitrogen gas containing 200% by volume and reducing at a temperature of 200 ° C., a city gas (13A gas) 150 (1 / h) having a composition shown in Table 1 below was passed through the desulfurization tube (GHS).
V = 1000h ^-1 ), temperature 200 ° C, pressure 0.02kg / c
It was desulfurized under the condition of m ² · G. When the sulfur content in the desulfurization gas was measured over time by the cold trap method, 1300 was obtained.
Over time, it was less than 0.1 ppb.

[0017]

Example 6 Copper nitrate, zinc nitrate and aluminum hydroxide were mixed at a molar ratio of 1:
A mixed aqueous solution containing at a ratio of 1: 0.3 is added dropwise to an aqueous sodium carbonate solution kept at about 60 ° C. while stirring to form a precipitate. The precipitate is thoroughly washed with water, filtered and dried. Next, it is baked at about 280 ° C., and once slurried with water, filtered and dried, and is 1/8 inch in diameter × 1 length.
It was tableted to / 8 inch. Then, about 150c of the fired body
A nitrogen gas containing 1% by volume of hydrogen was passed through a desulfurization tube filled with c (desulfurization layer length 30 cm) and reduced at a temperature of 200 ° C., and then a city gas having the composition shown in Table 1 was passed through the desulfurization tube. (13A gas) through 150 (1 / h) (GHSV
= 1000h ^-1 ), temperature 200 ° C, pressure 0.02kg / c
It was desulfurized under the condition of m ² · G. When the sulfur content in the desulfurization gas was measured over time by the cold trap method, 1300 was obtained.
Over time, it was less than 0.1 ppb.

────────────────────────────────────────────────── ─── Continuation of the front page (72) Katsuhiko Hirao Inventor 4-1-2, Hirano-cho, Chuo-ku, Osaka City Inside Osaka Gas Co., Ltd. (56) References JP-A-2-302303 (JP, A) JP Hei 1-123628 (JP, A) JP-A-62-282637 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B01J 20/00-20/34

Claims (3)

(57) [Claims] 1. A copper oxide-zinc oxide-aluminum oxide mixture prepared by mixing a copper compound, a zinc compound and aluminum hydroxide with an aqueous solution of an alkaline substance to form a precipitate and calcining the resulting precipitate. A method for producing a desulfurizing agent, comprising reducing hydrogen. 2. The method for producing a desulfurizing agent according to claim 1, wherein hydrogen reduction is performed at 150 to 300 ° C. 3. The method for producing a desulfurizing agent according to claim 2, wherein hydrogen reduction is performed using a diluted hydrogen gas having a hydrogen concentration of 6% or less with an inert gas.