JP2003047861A - Method of manufacturing catalyst for dimethyl ether and method of manufacturing dimethyl ether - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a catalyst for manufacturing a dimethyl ether at a high yield and a method of manufacturing the dimethyl ether at a high space time yield. SOLUTION: This method of manufacturing the catalyst for manufacturing the dimethyl ether comprises suspending a methanol synthesis catalyst, methanol dehydration catalyst and aqueous gas shift catalyst in a solvent in such a manner that all of the differences in the values of A expressed by the following equation between the respective catalysts attain the values within ±1×10<-6> g/cm: A=D<2> .(P-S) where, D is the average grain size of the catalyst and its unit is cm; P is the density of the catalyst and its unit is g/cm<3> and S is the density of the solvent and its unit is g/cm<3> . This method of manufacturing the dimethyl ether comprises circulating a gaseous mixture composed of carbon monoxide and hydrogen or a gaseous mixture included with carbon dioxide and/or steam further therein through the catalyst obtained by the method of manufacturing the same described above.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a catalyst for producing dimethyl ether, and a method for producing dimethyl ether by passing a mixed gas of carbon monoxide and hydrogen through a slurry obtained by suspending the catalyst in a solvent. It is about.

[0002]

2. Description of the Related Art Conventionally, in the presence of a catalyst suspended in a solvent,
There are several known methods for producing dimethyl ether from a mixed gas of carbon monoxide, carbon dioxide and hydrogen.

For example, JP-A-2-9833, JP-A-3-181435, JP-A-3-52835, JP-A-4-264046 and JP-A-5-810.
069 (WO93 / 10069) discloses a method for producing dimethyl ether or a mixture of dimethyl ether and methanol by catalyzing a mixture of a methanol synthesis catalyst and a methanol dehydration catalyst suspended in an inert liquid with synthesis gas. There is.

The method disclosed in Japanese Patent Application Laid-Open No. Hei 2-9833 is a method in which a synthesis gas consisting of hydrogen, carbon monoxide and carbon dioxide is contacted with a solid catalyst and reacted in the presence of the solid catalyst. In a direct process for the synthesis of dimethyl ether, said synthesis gas is contacted in the presence of a solid catalyst system, wherein said solid catalyst is a single catalyst suspended in a liquid medium in a three-phase (liquid phase) reactor system or A mixture of catalysts, wherein the three-phase reactor system is a direct synthesis of dimethyl ether from synthesis gas consisting of at least one three-phase reactor.

The method disclosed in Japanese Patent Application Laid-Open No. 3-181435 is a method for producing dimethyl ether from a mixed gas of carbon monoxide and hydrogen, or a mixed gas containing carbon dioxide and / or steam. In the method for producing dimethyl ether, the catalyst is suspended in a solvent and used in a slurry state.

In the method disclosed in Japanese Patent Laid-Open No. 3-52835, synthesis gas is reacted in the presence of a solid methanol synthesis catalyst to produce methanol, and the produced methanol is reacted in the presence of a solid dehydration catalyst. To produce dimethyl ether. In a method of synthesizing dimethyl ether from a synthesis gas consisting of hydrogen, carbon monoxide and carbon dioxide, the synthesis gas is contacted and reacted in the presence of a solid catalyst system consisting of a methanol synthesis component and a dehydration (ether formation) component, A single catalyst or a mixture of catalysts in a liquid medium in the solid catalyst system three-phase (liquid phase) reactor system, wherein the reactor system is operated to obtain a minimum effective methanol rate of at least one hour. This is a dimethyl ether synthesis method characterized in that the amount of methanol is maintained at 1.0 g / kg of catalyst.

The method disclosed in Japanese Patent Publication (KOKAI) No. 5-810069 is based on a mixed gas containing carbon monoxide and one or both of hydrogen and steam, or a mixed gas containing carbon dioxide. In the method for producing dimethyl ether, at least zinc oxide,
A method for producing dimethyl ether, which comprises pulverizing a mixed catalyst containing copper oxide or chromium oxide and aluminum oxide, bringing the catalyst into close contact with the catalyst, and then re-pulverizing the catalyst to be suspended in a solvent and used in a slurry state.

[0008]

However, JP-A-2-9833, JP-A-3-52835, JP-A-4-264046 and JP-A-3-181435.
In the method for producing dimethyl ether disclosed in Japanese Unexamined Patent Publication No. 2003-242, since there is a difference in specific gravity between a methanol synthesis catalyst and a methanol dehydration catalyst or a water gas shift catalyst, these two or three catalysts suspended in a solvent in a reactor are separated. However, there is a problem that the catalyst utilization efficiency is remarkably lowered due to the concentration distribution of the catalyst or the sedimentation of one catalyst.

Further, the catalyst disclosed in JP-A-5-810069 is a mechanically integrated one of the above-mentioned three kinds of catalysts. There was a problem that the catalyst was peeled off to cause catalyst concentration distribution and sedimentation.

An object of the present invention is to solve the above problems and provide a catalyst for producing dimethyl ether in high yield and a method for producing dimethyl ether with high space-time yield.

[0011]

The present invention has been made in order to achieve the above object, and the present inventors show a methanol synthesis catalyst, a methanol dehydration catalyst and a water gas shift catalyst by the following formulas. A method for producing a catalyst for producing dimethyl ether, characterized in that the catalyst is suspended in a solvent such that the difference in the value of A between the catalysts is within ± 1 × 10 ⁻⁶ g / cm, and A = D ² · (PS) where D is the average particle size of the catalyst in cm, P is the particle density of the catalyst in g / cm ³ , and S is the density of the solvent in g / cm ^3. Up to, by using the catalyst produced by this method in a solvent by suspending it in a solvent, a mixed gas of carbon monoxide and hydrogen, or a mixed gas containing carbon dioxide and / or steam, High yield of dimethyl ether The present invention has been completed by finding that it can be produced at a high rate and a high space-time yield.

In the present invention, the methanol synthesis catalyst, the methanol dehydration catalyst and the water gas shift catalyst are prepared by controlling the particle densities and particle sizes of the catalysts and then physically mixing them, so that the various catalysts are separated during the reaction. Without them, the distances of the catalysts are brought close to each other, so that the reaction cycle described below rapidly proceeds and the yield of dimethyl ether is improved. That is, in this reaction, first, methanol is produced from carbon monoxide and hydrogen on the methanol synthesis catalyst, and then methanol is transferred onto the methanol dehydration catalyst to produce dimethyl ether and water by dehydration condensation. Further, water moves to the water gas shift catalyst and / or the methanol synthesis catalyst and reacts with carbon monoxide to produce carbon dioxide and hydrogen. The reaction formula is as follows.

CO + 2H ₂ → CH ₃ OH (1) 2CH ₃ OH → CH ₃ OCH ₃ + H ₂ O (2) CO + H ₂ O → CO ₂ + H ₂ (3)

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The catalyst used in the present invention basically comprises a methanol synthesis catalyst, a methanol dehydration catalyst and a water gas shift catalyst. The methanol synthesis catalyst is an excellent water gas shift catalyst, It can also serve as a water gas shift catalyst.

Examples of methanol synthesis catalysts include copper oxide-zinc oxide-alumina and zinc oxide-chromium oxide-alumina. The weight ratio of copper oxide to zinc oxide and alumina is about 0.05 to 20 zinc oxide, preferably about 0.1 to 5 zinc oxide, and about 0 to 2 alumina, preferably 0 to 1 with respect to 1 copper oxide. In the case of zinc oxide, chromium oxide, and alumina, the weight ratio of zinc oxide to zinc oxide is 1.0.
1 to 10, preferably 0.5 to 5, alumina 0
It is about 2 to 2, preferably about 0 to 1. Examples of the methanol dehydration catalyst include γ-alumina, silica / alumina, and zeolite. As the metal oxide component of zeolite, oxides of alkali metals such as sodium and potassium,
Examples thereof include oxides of alkaline earth metals such as calcium and magnesium. Examples of the water gas shift catalyst include copper oxide zinc monoxide and iron oxide-chromium oxide. The weight ratio of copper oxide to zinc oxide is 0.1 to 1 zinc oxide.
To about 20, preferably about 0.5 to 10, and the weight ratio of iron oxide to chromium oxide is about 0.1 to 20, preferably about 0.5 to 10 chromium oxide to 1 iron oxide. . Further, as a catalyst that also serves as a methanol dehydration catalyst and a water gas shift catalyst, there is copper (including copper oxide) -alumina or the like.

Each of these catalysts may be produced by a known method. For example, a water-soluble salt of each metal component is used to prepare an aqueous solution containing them. The salt may be either an inorganic acid salt or an organic acid salt as long as it is water-soluble. However,
Those that are prone to hydrolysis to form hydroxides when added to water are not suitable. For example, nitrates, carbonates, organic acid salts, halides, etc. can be used. The concentration of each component may be about 0.1 to 3 mol / l. Then, a base is added to this aqueous solution to neutralize the solution to precipitate a hydroxide, and solid-liquid separation is performed, followed by washing, drying, and further firing. Moreover, a commercial item can also be used.

The mixing ratio of the above-mentioned methanol synthesis catalyst, methanol dehydration catalyst and water gas shift catalyst is not particularly limited and may be appropriately selected according to the type of each component, reaction conditions and the like, but is usually in a weight ratio. A methanol dehydration catalyst of about 0.5 to 10 and a water gas shift catalyst of about 0 to 5 are often suitable for one methanol synthesis catalyst.

The difference in the value of A calculated by the above equation between the catalysts is preferably within 1 × 10 ⁻⁶ g / cm as described above, but more preferably 5 × 10 ^−7. Within g / cm. When the difference between the values of A is larger than 1 × 10 ⁻⁶ g / cm, the conversion rate of carbon monoxide becomes low. The method of controlling the value of A is not particularly limited, but since the density of the solvent does not change so much in general, the average particle size and particle density of the catalyst are mainly used. Further, the particle density generally does not change so much if the average particle size is constant, so it is easy to control the average particle size first. As a method for controlling the average particle diameter, there is pulverization by a ball mill or the like. The average particle size is measured according to the sieving method (JIS Z 8801-1982), the sedimentation method, etc. The particle density is measured by the specific gravity bottle method (JIS.
R-5201), buoyancy method (JISR6125).

The above catalyst is used by suspending it in a solvent to form a slurry. The amount of the catalyst to be present in the solvent is appropriately determined depending on the type of the solvent, the reaction conditions, etc., but is usually 1 to 50% by weight with respect to the solvent.

Any solvent can be used as the solvent used in the synthesis of dimethyl ether in the present invention as long as it exhibits a liquid state under the reaction conditions. For example,
Aliphatic, aromatic and alicyclic hydrocarbons, alcohols,
Ethers, esters, ketones and halides, mixtures of these compounds and the like can be used.

Further, gas oil from which sulfur has been removed, vacuum gas oil,
High boiling point fractions of hydrotreated coal tar can also be used.

By passing a mixed gas of carbon monoxide and hydrogen through the catalyst-solvent slurry thus formed, dimethyl ether can be obtained in a high yield. A wide range of mixing ratios (H ₂ / CO ratio) of hydrogen and carbon monoxide can be applied. For example, the H ₂ / CO molar ratio is 20 to
A mixture ratio of 0.1, preferably 10 to 0.2 can be used.

In this reaction system, the mixed gas does not come into direct contact with the catalyst as in the gas-solid catalytic reaction, but once carbon monoxide and hydrogen are dissolved in the solvent, they come into contact with the catalyst. By selecting the solvent in consideration of the solubility of carbon oxide and hydrogen in the solvent, it is possible to achieve a constant composition of carbon monoxide and hydrogen in the solvent regardless of the gas composition and further supply it to the catalyst surface. It is possible.

On the other hand, the ratio of hydrogen to carbon monoxide (H ₂ / CO
In the case of a mixed gas with a very small ratio (for example, 0.1 or less) or carbon monoxide that does not contain hydrogen, a separate steam is supplied and a part of the carbon monoxide is steamed into hydrogen and carbon dioxide. Need to be converted to.

Further, since the solvent is present between the raw material gas and the catalyst, the gas composition and the composition on the surface of the catalyst do not necessarily match. Therefore, in the mixed gas of carbon monoxide and hydrogen or in the carbon monoxide gas. Relatively high concentration (20-50%)
Carbon dioxide may be present.

Further, according to the production method of the present invention, even if the raw material gas contains a sulfur poison compound such as hydrogen sulfide, a cyanide compound such as hydrogen cyanide, a chlorine compound such as hydrogen chloride, or the like, which is a catalyst poison, the catalyst may be added to the catalyst. The effect is significantly reduced compared to the gas-solid contact method. Incidentally, when the catalyst is poisoned and its activity is lowered, the slurry is extracted from the reactor,
By newly pressing the slurry containing the highly active catalyst into the reactor, the productivity of the entire reactor can be kept constant.

The reaction heat is recovered as medium pressure steam by installing a cooling coil in the reactor and passing hot water through it. This allows the reaction temperature to be freely controlled.

The reaction temperature is preferably 150 to 400 ° C,
The range of 200 to 350 ° C. is particularly preferable. Reaction temperature is 1
If it is lower than 50 ° C or higher than 400 ° C, the conversion rate of carbon monoxide is low.

The reaction pressure is preferably 10~300kg / cm ^2, in particular 15~150kg / cm ^2. If the reaction pressure is lower than 10 kg / cm ^2, the conversion rate of carbon monoxide is low, and if it is higher than 300 kg / cm ² , the reactor becomes special, and a large amount of energy is required for pressurization, which is economical. Not.

The space velocity (feed rate of the mixed gas in a standard state per 1 g of catalyst) is 100 to 50,000 ml.
/ G · h is preferable, especially 500 to 30,000 ml / g
・ It is h. If the space velocity is greater than 50,000 ml / g · h, the conversion rate of carbon monoxide will be low and it will be 100 ml.
If it is smaller than / g · h, the reactor becomes extremely large, which is not economical.

[0031]

EXAMPLE I. Catalyst Preparation Copper nitrate Preparation 1) catalyst _{(Cu (NO 3) 2 ·} 3H 2 O) 185g, zinc nitrate _{(Zn (NO 3) 2 ·} 6H 2 O) 117g and aluminum nitrate (Al (NO _{3) 3} · 9H ₂ O) (52 g) dissolved in about 1 liter of ion-exchanged water and sodium carbonate (Na ₂ C
An aqueous solution of about 200 kg of O ₃ ) dissolved in about 1 liter of ion-exchanged water was placed in a stainless steel container containing about 3 liters of ion-exchanged water kept at about 60 ° C. and the pH was maintained at 7.0 ± 0.5. While adjusting so that the mixture was added dropwise over about 2 hours. After the completion of dropping, the mixture was kept for about 1 hour for aging. In addition, if the pH deviates from 7.0 ± 0.5 during this period, an approximately 1 mol / l nitric acid aqueous solution or approximately 1 m
An ol / l sodium carbonate aqueous solution was added dropwise to adjust the pH to 7.0 ± 0.5. Next, the formed precipitate was filtered and then washed with ion-exchanged water until nitrate ions were not detected in the washing liquid. 120 cakes obtained
After drying at ℃ for 24 hours, it was further calcined in air at 350 ℃ for 3 hours to obtain the target catalyst.

The composition of the resulting catalyst was CuO: ZnO:
Al ₂ O ₃ = 61: 32: 7 (weight ratio).

2) Preparation of catalyst An aqueous solution prepared by dissolving 91 g of copper nitrate (Cu (NO ₃ ) ₂ .3H ₂ O) and 256 g of zinc nitrate (Zn (NO ₃ ) ₂ .6H ₂ O) in about 1 l of ion-exchanged water. , Sodium carbonate (Na ₂ C
An aqueous solution prepared by dissolving about 130 g of O ₃ ) in about 1 liter of ion-exchanged water is kept at a pH of 8.5 ± 0.5 in a stainless steel container containing about 3 liters of ion-exchanged water kept at about 60 ° C. While adjusting so that the mixture was added dropwise over about 2 hours.
After the completion of dropping, the mixture was kept for about 1 hour for aging.
In addition, if the pH deviates from 8.5 ± 0.5 during this period, a nitric acid solution of about 1 mol / l or about 1 mol / l
/ L sodium carbonate aqueous solution was added dropwise to adjust the pH to 8.5.
Adjusted to ± 0.5. Next, the formed precipitate was filtered and then washed with ion-exchanged water until nitrate ions were not detected in the washing liquid. The cake thus obtained was dried at 120 ° C. for 24 hours and then calcined in air at 350 ° C. for 3 hours to obtain a target catalyst.

The composition of the resulting catalyst was CuO: ZnO =
It was 3: 7 (weight ratio).

3) Preparation of catalyst 100 g of alumina (N612 manufactured by JGC Chemical Co., Ltd.) in air
After drying at 120 ° C. for 24 hours, it was calcined in air at 450 ° C. for 3 hours to obtain the desired alumina catalyst.

4) Preparation of catalyst Copper acetate (Cu (CH ₃ CO 2)
O) ₂ · H ₂ O) (15.7 g) was dissolved, 95 g of the alumina catalyst prepared in 3) above was added, and the mixture was evaporated to dryness. Then, this was dried in air at 120 ° C. for 24 hours and then calcined in air at 450 ° C. for 3 hours. Further, it was treated at 400 ° C. for 3 hours in a steam flow to obtain a catalyst. The composition of this product was Cu: Al ₂ O ₃ = 5: 95 (weight ratio).

[0037] 5) Preparation of aluminum nitrate catalyst _{(Al (NO 3) 3 ·} 9H 2 O) 736g
Was dissolved in about 2 liters of ion-exchanged water, and an aqueous solution of about 350 g of sodium carbonate (Na ₂ CO ₃ ) dissolved in about 2 liters of ion-exchanged water was placed in a stainless steel container containing about 3 liters of ion-exchanged water at room temperature. , PH was maintained at 7.5 ± 0.5, and the mixture was added dropwise over about 2 hours.
After the completion of dropping, the mixture was kept for about 1 hour for aging.
In addition, if the pH deviates from 7.5 ± 0.5 during this period, about 1 mol / l nitric acid solution or about 1 mol / l
/ L sodium carbonate aqueous solution was added dropwise to adjust the pH to 7.5.
Adjusted to ± 0.5. Then, the formed precipitate was filtered and then washed with ion-exchanged water until nitrate ions were not detected in the washing liquid. The cake thus obtained was dried at 120 ° C. for 24 hours and then calcined in air at 350 ° C. for 3 hours to obtain alumina.

Next, 15.7 g of copper acetate (Cu (CH ₃ COO) ₂ .H ₂ O) was dissolved in about 200 ml of ion-exchanged water,
After adding 95 g of the above alumina to this, it was evaporated to dryness. Then, this was dried in air at 120 ° C. for 24 hours and then calcined in air at 450 ° C. for 4 hours. Further, it was treated in a hydrogen stream at 400 ° C. for 3 hours to obtain a catalyst. The composition of this product was Cu: Al ₂ O ₃ = 5: 95 (weight ratio).

Example 1 The above catalyst was ground in a ball mill to give an average particle size of 16.
9 μm fine powder particles, and the above catalyst was ground in a ball mill into fine powder particles having an average particle size of 15.6 μm, and the catalyst was further ground in a ball mill to obtain a fine powder having an average particle size of 15.5 μm. It was made into particles. Then, 2.4 g of the fine powdery particulate catalyst, 1.2 g of the fine powdery particulate catalyst and 1.2 g of the fine powdery particulate catalyst were taken and physically mixed.

Example 2 The above catalyst was ground in a ball mill to give an average particle size of 16.
It was made into fine powder particles of 9 μm, and the above catalyst was ground in a ball mill to obtain fine powder particles having an average particle size of 15.2 μm. Then, 2.4 g of the fine powdery particulate catalyst and 1.2 g of the fine powdery particulate catalyst were taken and physically mixed.

Example 3 2.4 g of a catalyst having an average particle size of 14.4 μm and an average particle size of 12.
1.2 g of 9 μm catalyst were physically mixed.

Example 4 2.4 g of a catalyst having an average particle size of 16.9 μm and an average particle size of 18.
1.2 g of 4 μm catalyst were physically mixed.

Comparative Example 1 A catalyst was mixed in the same manner as in Example 1 except that the average particle size of the catalyst was 20.1 μm and the average particle size of the catalyst was 18.5 μm.

Comparative Example 2 A catalyst was mixed by the same method as in Example 2 except that the average particle size of the catalyst in Example 2 was 12.9 μm.

II. Catalyst activation method and reaction method To a bubble column reactor having an inner diameter of 2 cm and a height of 2 m, 24 g (31.1 ml) of n-hexadecane was added, and the above-mentioned powdery particulate mixed catalyst was further added thereto to obtain a suspension state. I chose Then, hydrogen in this bubble column, carbon monoxide and a mixed gas consisting of nitrogen _{(H2: CO: N 2 =} 1: 1: 9, molar ratio) while circulated at a flow rate of about 300 ml / min, 2 from room
The temperature was gradually raised to 20 ° C. over several hours, at the same time, the concentration of nitrogen in the mixed gas was finally gradually decreased to 0, and the temperature was further maintained at 220 ° C. for about 3 hours to activate the catalyst. .

The reaction is carried out at a predetermined reaction temperature and reaction pressure under the conditions of H 2
₂ / CO / CO ₂ ratio is 47.5 / 47.5 / 5.
A mixed gas of hydrogen, carbon monoxide, and carbon dioxide of 0 at room temperature,
The flow was performed at a flow rate of 336 ml / min in terms of atmospheric pressure.

The reaction products and unreacted products obtained by the above operation were analyzed by gas chromatography.

III. Reaction conditions and experimental results The reaction conditions and experimental results are shown in Tables 1 and 2.

[0049]

[Equation 1]

[0050]

[Equation 2]

[0051]

[Equation 3]

[0052]

[Equation 4] All units of each speed are [mol / g-cat · h]

[0053]

[Table 1]

[0054]

[Table 2]

[0055]

INDUSTRIAL APPLICABILITY Since the catalyst for producing dimethyl ether of the present invention controls the particle densities and particle sizes of the methanol synthesis catalyst, the methanol dehydration catalyst and the water gas shift catalyst according to the equations, these catalysts may be separated during the reaction. Therefore, the reaction cycle smoothly proceeds and a high dimethyl ether yield can be obtained.

Further, in the method for producing dimethyl ether of the present invention, a catalyst in which a methanol synthesis catalyst, a methanol dehydration catalyst and a water gas shift catalyst are integrated is suspended in a solvent and used in a slurry state. The yield is high, there is no problem with catalyst clogging or mechanical strength of the catalyst, it is easy to remove the heat of reaction and control the reaction temperature, and the ratio of carbon monoxide to hydrogen is applicable. A wide range of reactions are possible in the presence of high-concentration carbon dioxide, and the effects of impurities and catalyst poisons are small.

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 4G069 AA03 AA08 BA01B BB02B                       BB04B BC31B BC35B CC29                       EB18X EB18Y EC21X EC21Y                       FA01 FB06 FB07 FC10                 4H006 AA02 AC43 BA05 BA07 BA09                       BA30 BE20 BE40                 4H039 CA61 CL35

Claims (2)

[Claims] 1. A methanol synthesis catalyst, a methanol dehydration catalyst and a water gas shift catalyst are represented by the following formula:
The method for producing a catalyst for producing dimethyl ether, characterized in that the catalysts are suspended in a solvent such that the difference in the value of each catalyst is within ± 1 × 10 ⁻⁶ g / cm, and A = D ² · ( Where P is the average particle size of the catalyst in cm, P is the particle density of the catalyst in g / cm ³ , and S is the density of the solvent in g / cm ³ . 2. The catalyst obtained by the production method according to claim 1,
A method for producing dimethyl ether, characterized in that a mixed gas of carbon monoxide and hydrogen, or a mixed gas further containing carbon dioxide and / or steam is circulated.