JPS6253739A - Preparation of methanol synthesizing catalyst - Google Patents

Abstract

PURPOSE:To enhance catalytic activity, by mixing an aqueous slurry of zinc with a crystal size of 1,000Angstrom or less and a precipitate slurry of a copper component and blowing carbon dioxide in the resulting mixture to form a precipitate which is, in turn, baked in the presence of an alumina precursor. CONSTITUTION:An aqueous solution of a water-soluble copper salt is mixed with an aqueous solution of alkali selected from alkali carbonate, alkali bicarbonate and alkali hydroxide to precipitate a copper component. The precipitate slurry of the copper component is mixed with an aqueous slurry of zinc oxide with an average crystal size of 1,000Angstrom or less or zinc oxide, and carbon dioxide is blown in the resulting mixture to convert the zinc component to basic zinc carbonate. Subsequently, the precipitate mixture is baked in the presence of an alumina precursor compound to prepare a methanol synthesizing catalyst. It is pref. to hold the slurry solution containing copper and zinc components at about 60-80 deg.C for about 5min.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a method for producing a methanol synthesis catalyst. More specifically, the present invention relates to a method for producing a highly active methanol synthesis catalyst that can be applied to various processes and that enables a significant reduction in catalyst production costs by converting conventionally used catalyst raw materials.

(Prior art) In the methanol synthesis process, in recent years, there has been an increasing demand for methanol synthesis under a relatively low pressure of about 50 to 150 atmospheres, with the aim of saving energy by reducing compression power costs. There is a need for better catalysts. In order to meet this demand, a methanol synthesis catalyst consisting of copper-zinc and aluminum oxides (Japanese Patent Publication No. 45-1
+5682 and Japanese Patent Publication No. 4 B-23265) - and a methanol synthesis catalyst consisting of copper-zinc-aluminum and boron oxides (Japanese Patent Publication No. 51-44715), and a method for producing this catalyst from cheaper raw materials (l\f Kosho 59-
1025(S) and the like are known.

(Problem to be solved by the invention) On the other hand, from the demand side, as the use of methanol as fuel is being greatly promoted, there has been a demand for methanol synthesis plants to be larger with an increase in K. In order to cope with this, it is desired to develop a process that saves energy by using a highly active catalyst and carrying out the reaction under low pressure.

The present invention solves the above problems, reduces catalyst manufacturing costs,
The aim is to develop a catalyst with higher activity while maintaining the simplification of the manufacturing process.

(Means for Solving the Problems) That is, the present invention provides (a) an aqueous solution of a water-soluble copper salt which may contain a water-soluble boron compound; A step of mixing an aqueous alkali solution selected from alkali carbonate and alkali hydroxide to precipitate the copper component (along with the boron component if a boron compound is present), (b) a precipitated slurry of the copper component obtained in the 1 ml step above; , a step of mixing an aqueous slurry solution of zinc oxide or zinc oxide powder which may contain a water-soluble boron compound, and blowing carbon dioxide into this to convert the zinc component into basic zinc carbonate; In manufacturing the catalyst by calcining the precipitate mixture in the presence of an alumina precursor compound, the following zinc oxide with a crystallite diameter of 1000 is used as the zinc oxide used in step (b): copper, This is a method for producing a methanol synthesis catalyst that contains zinc and aluminum oxide as essential components and optionally contains a boron compound.

The water-soluble copper salts used in the above (ATL process) include conventionally used water-soluble salts of copper, and include catalyst poisons such as halogens and sulfur in water-soluble solutions such as nitrates, oxalates, and acetates. Salts that do not contain such elements are preferred, and nitrates are particularly suitable.

Such water-soluble copper salts have an aqueous medium, such as water (deionized water).
In the dissolved state, it is precipitated with a precipitant selected from alkali carbonates, alkali bicarbonates and alkali hydroxides. The concentration of the water-soluble copper salt in the water-soluble solution at that time is:

Although it can vary widely depending on the type of copper salt used, it is generally 0.
．． 1 to 1.0 mol/! (much lower than the solubility).

As a precipitant for precipitating the copper component as an insoluble solid from the aqueous solution of the water-soluble copper salt.

Such as KHCO3. It is convenient to use the precipitant in the form of an aqueous solution, the amount of precipitant component used being at least 0.8 times the amount of the copper salt, preferably 1.0 times the amount of the precipitant component relative to the copper salt.
It is advantageous to use trays of ~2 equivalents, more preferably 1.0 to 1.3 times equivalents. The precipitation reaction may be carried out at room temperature or with heating as appropriate, but it is advantageous to carry out the precipitation reaction at a temperature of up to about 50°C.

On the other hand, as the zinc component in step (b), zinc oxide having an average crystallite diameter of 100 OA' or less, preferably /I'1500 A0 or less is used. The average crystallite size of commercially available zinc oxide is 2000 to 5oooA0, and zinc oxide with such a microcrystalline size is not commercially available, but it can be used for thermal decomposition of basic zinc carbonate and zinc carbonate, and for hydrolysis of organic zinc compounds. The zinc oxide used in this process, which can be produced by such methods and can be easily procured industrially, can be added as is to steel slurry (a solution precipitated with an alkali component). However, it is more advantageous to mix it with water (deionized water) to form a slurry in advance and add it in a well-dispersed state in the solution. The mixing ratio of zinc oxide and water is not particularly limited, but is generally preferably adjusted to 5 to 50% by weight. This slurry preparation can be carried out at room temperature, but may also be carried out while being heated to a temperature of up to 50°C.

The carbonation step may be carried out with the slurry solution kept at room temperature, or may be carried out with appropriate heating up to about 100"C. The carbon dioxide gas used is generally commercially available liquefied carbonic acid. A preferred method is to vaporize and blow in carbon dioxide gas. Carbonation can be easily carried out by appropriately blowing in an amount of carbon dioxide gas that is greater than the theoretical amount.

If alkali carbonate is used to precipitate copper,
Since carbon dioxide gas is also generated during this reaction, an amount less than the theoretical amount may be sufficient in some cases. The blowing time and blowing speed are the temperature of the solution.

The slurry solution containing the copper and zinc components produced as described above can be subjected to subsequent processing as it is, but at a temperature of 60 to 100°C, especially 60 to 80°C, for at least 5 minutes. 1. It is preferable to ripen by holding for 10 to 60 minutes.

In addition, in the present invention, when the purpose is to produce a Cu-Zn-AI-B four-way catalyst, the above (a) is carried out prior to the precipitation formation reaction or carbon dioxide gas blowing.

(The water-soluble compound of boron may be dissolved in one or all of the copper salt aqueous solution, alkaline aqueous solution, and zinc oxide slurry solution in the BL step. It depends on the content of boron component required in the original catalyst.

It may be added as appropriate to give an atomic ratio of 0.1 to 1.5 with respect to zinc. The exact mechanism by which the water-soluble boron compound precipitates is not known, and varies depending on the location where the water-soluble boron compound is added, but it is presumed to be due to coprecipitation or physical adsorption. Even when this water-soluble boron compound is used, there is no need to particularly change the amount of precipitant or carbon dioxide used, and the process can be carried out under substantially the same conditions as when the water-soluble boron compound is not used. I can do it.

The mixed slurry produced by the above method is sent to the next step of firing in the presence of an alumina precursor compound. Various methods can be used to add the alumina precursor compound at this time. For example - after adding the alumina precursor compound to the steel and zinc mixed slurry, the mixture is separated from the solution by conventional means such as filtration, washed to remove excess precipitant or water-soluble salts formed, and then dried. or a method in which the steel and zinc mixed slurry is separated from the solution by ordinary means such as filtration, washed to remove excess precipitant or generated water-soluble salts, and then mixed with an alumina precursor compound;
Y! For example, a method may be adopted in which an alumina precursor compound is added after drying the above-mentioned washed copper/zinc mixture.

In the present invention, what is an alumina precursor compound?

It is a substance that thermally decomposes to give alumina under the calcination conditions described below, and does not leave any substances harmful to the catalyst of the present invention after decomposition. means aluminum hydroxide etc. obtained by precipitation with a precipitating agent. Commercially available alumina sol can be used as this precursor compound, and if necessary, one reaction system may include one water-soluble aluminum salt, such as sodium aluminate, aluminum acetate, etc.
By precipitating the alumina precursor together with the copper component in the coexistence of aluminum nitrate, etc., the alumina precursor compound may be present in the mixed precipitate as a result, and if necessary, , the alumina precursor compound added to the mixed precipitate includes Ml*Z
Oxide precursors such as rz TJb Mn+ Cr+ st, such as hydroxides, carbonates, etc., or phosphorous oxyaltates, etc. can be included.

The precipitate mixture produced as described above is subjected to appropriate treatments such as mixing and drying by known means.

Fire. Firing is performed in an oxygen-containing gas atmosphere using equipment such as an electric furnace, a combustion gas firing furnace, or a fluidized bed firing furnace.
This can be carried out by heating at a temperature of 280 DEG C. to 500 DEG C., preferably 300 DEG C. to 450 DEG C., for 0.5 to 4 hours.

The catalyst thus obtained may be used as it is or, if necessary, may be pulverized and molded using a tablet machine. The molding method can obtain sufficient strength as an industrial catalyst with one molding, but the first molding is preforming, which is then pulverized.
If the catalyst is re-formed into tablets, a catalyst with even better strength can be obtained.

The composition of the catalyst of the present invention is that the atomic ratio of Cu:Zn is 0°2 to 1.
The ratio is in the range of 2:1, preferably 0.3 to 7:1. In the case of catalysts that are used after being formed into tablets, Cu-Zn-
Al! In the three-way catalyst, the ratio of each component is based on the atomic ratio: Cu is 45 to 80%, preferably 5[]-770%, Zn is 15%.
~50%, preferably 20-45%, AI 1-20%
, preferably 4 to 16%. Cu-Zn-AJf
In the -B four-way catalyst, the ratio of each component is based on the atomic ratio, Cu
is 45-80%, preferably 50-70%, Zn is 1
5-50%, preferably 20-45% 1M is 1-16%
, preferably 3 to 12%, and B is 0.3 to 5%, preferably 0.5 to 3%.

In the catalyst of the present invention, the presence of some metal atoms mixed in other than the above-mentioned components is allowed.
It does not matter if it contains 8 degrees of ~a o o ppm.

The catalyst produced by the method of the present invention is activated by, for example, reduction with hydrogen, and then CO and/or C
It can be used as a catalyst for reactions such as synthesis of methanol from a mixed gas of O2 and H2, CO expansion reaction, hydrogenation reaction, and methanol decomposition reaction.

The methanol synthesis reaction using the catalyst of the present invention is as follows.

20-300 Lm, preferably 30-150 aty
Under pressure of n, 150-550°C, preferably 200-6
At a temperature of 00℃, 2000~50 o o o h
This can be done with a space velocity of r.

(Effects of the invention) Compared to conventional catalysts of the same type, the catalyst of the present invention has 1.5 to 2 times higher activity without sacrificing other advantages of conventional catalysts, and is suitable for various methanol synthesis processes. can adapt,
Particularly in large plants, this has the great advantage of saving energy and requiring less catalyst usage.

(Example) Example 1 Copper nitrate 195I was dissolved in ion exchange water 1490d,
Maintain the liquid temperature at 40°C. Next, ammonium bicarbonate 13
After dissolving 4I in 1130 ml of ion-exchanged water and bringing the temperature of the solution to 40° C., the copper nitrate aqueous solution is added while stirring to prepare a copper slurry.

On the other hand, 32 d of basic zinc carbonate was added to 400 d of ion-exchanged water.
Charge zinc oxide 49.4.9 with an average crystallite diameter of 280 A° obtained by thermal decomposition at 0°C, and stir for 30 minutes to prepare a zinc oxide slurry solution. This is added to the steel slurry solution, and carbon dioxide gas is blown in at a flow rate of 61/hr. At this time, the liquid temperature is maintained at 40°C, and after 40 minutes, the liquid temperature is raised to 70°C, and the reaction is continued at this temperature for 30 minutes to perform ripening. Next, the obtained Cu-Zn slurry solution was filtered and washed, and then alumina sol (Az2o310
%) 60I and knead for 30 minutes using a kneader. After kneading, it was dried at 110°C for 12 hours, then put into a baking furnace and heated for 3
Calcinate at 70"C for 25 hours.The catalyst obtained after firing is
After crushing to 4 mesh or less and mixing 3% graphite, 6
One tablet was produced by compression molding into a size of 5 mm. The composition of this catalyst is Cu:Zn:AJ with a metal atomic ratio of 1.3.
The ratio is 3:1.0:0.19. Further, the specific surface area of this catalyst was 65 m''/I, the pore volume was 0.27 cc/II, and the average pore diameter was 98A.

Wing Example 2 In Example 1, steel acetate (monohydrate) 104.6# was used instead of nitrate steel 195.9, and ammonia water (concentration 25%) 132II was used instead of ammonium bicarbonate. A catalyst was produced in exactly the same manner as in Example 1, except that the reaction was carried out using

Example 3 Copper nitrate 2281 and boric acid 14.6 & ion-exchanged water 16
Dissolve in 80m/ml and maintain the liquid temperature at 30°C. Next, ammonium bicarbonate 16411 was added to ion-exchanged water 1380-
After dissolving the solution and bringing the temperature to 30°C, the copper nitrate aqueous solution was added while stirring.

Prepare a copper slurry tube.

On the other hand, the average crystallite diameter obtained by thermally decomposing basic 1Ih-lead carbonate at 280°C in 300 d of ion-exchanged water was 22OA.
Contains 38.511% of zinc oxide.

Stir for 30 minutes to prepare a zinc oxide slurry solution. Add this to the steel slurry solution and add C02 to 61/h.
Blow at a flow rate of r. At this time, the solution was kept at 30℃ for 1 h.
After passing through the rr, the liquid temperature was raised to 65°C.

The reaction is continued at this temperature for 30 minutes to effect aging.

did. Thereafter, a catalyst was prepared in the same manner as in Example 1.

Example 4 Copper nitrate (195.9%) was dissolved in 1490wJK of ion-exchanged water, and the temperature of the solution was maintained at 30°C. Next, sodium hydroxide 68
After dissolving I in water 113Q+lj and bringing the temperature of the solution to 30° C., the copper nitrate aqueous solution is added while stirring to prepare a copper slurry.

On the other hand, zinc oxide 49 with an average crystallite diameter of 280 people was obtained by thermally decomposing basic zinc carbonate in ion-exchanged water at 320°C.
．． 4Il was charged and stirred for 30 minutes to prepare a zero zinc oxide solution slurry. Add this to the steel slurry solution and c
Blow in o2 at a flow rate of 61/hr. At this time, liquid temperature t-4
The liquid was kept at 0°C and after passing through the gauze for 1.5 hours, the temperature was raised to 80°C.

Thermal aging was carried out at the same temperature for 1 hr. The obtained Cu-Zn slurry solution was filtered and washed. Alumina sol 6 (1?) was added to this cake and kneaded with a kneader.

Thereafter, a catalyst was prepared in the same manner as in Example 1.

Example 5 In Example 1 and 2, zinc oxide with an average crystallite diameter of 400 large obtained by thermally decomposing basic zinc carbonate at 420°C was used instead of zinc oxide with an average crystallite diameter of 280A. Except for this, a catalyst was prepared in exactly the same manner as in Example 1.

Comparative Example 1 A catalyst was prepared in exactly the same manner as in Example 1, except that zinc oxide with an average crystallite diameter of 2000 A was used instead of zinc oxide with an average crystallite diameter of 220 A in Example 1.

Comparative Example 2 A catalyst was prepared in exactly the same manner as in Example 3, except that zinc oxide having an average crystallite diameter of 2000 A was used instead of zinc oxide having an average crystallite diameter of 220 A in Example 3.

Test Example 1 Seven catalysts (Examples 1 to 5 and Comparative Examples 1 to 2) produced in the above manner were each ground into 20 to 40 meshes and kept at 140°C in a N2 stream to avoid rapid heat generation. The temperature was raised while gradually adding a reducing gas (synthesis raw material gas), and the catalyst was finally reduced by K at 240° C. for 3 hours. Then H270%-C025%, 002
Methanol synthesis was carried out using a synthesis raw material gas consisting of 5% CH, 41% CH, and 21% N at a pressure cuff of 0 atm, a space velocity of 2 x 10'hr'', and a reaction temperature of 260°C. Also, in order to know the life of the catalyst in a short period of time, the catalyst temperature t360
After raising the temperature to ℃ and performing methanol synthesis for 2 hours,
Catalytic activity when the temperature was lowered again to 260°C, and 360°C
Treat for 4 hours at a temperature of 26°C (total of 6 hours), then increase the temperature again to 26°C.
The catalytic activity was measured when the temperature was lowered to 0°C, the catalytic activity was further increased to 660°C for 4 hours (total of 10 hours), and the catalytic activity was measured when the temperature was lowered again to 260°C. The values expressed in concentration are shown in Table 1.

Claims (1)

[Scope of Claims] (a) An aqueous solution of a water-soluble copper salt that may contain a water-soluble boron compound, and an alkali carbonate, an alkali bicarbonate, and an alkali hydroxide that may contain a water-soluble boron compound. a step of precipitating the copper component (along with the boron component if a boron compound is present) by mixing an alkaline aqueous solution containing the copper component and the water-soluble boron compound; A process of mixing an aqueous slurry solution of zinc oxide or zinc oxide powder, which may be used as an alumina precursor, and blowing carbon dioxide gas into it to convert the zinc component into basic zinc carbonate. When producing a catalyst by calcination in the presence of a compound, (
b) Zinc oxide used in the process has an average crystallite diameter of 10
A method for producing a methanol synthesis catalyst containing copper, zinc and aluminum oxides as essential components and containing a boron compound as appropriate, characterized by using zinc oxide with a temperature of 00A° or less