JPH049775B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a method for producing ethylene-rich lower olefins from methanol and/or dimethyl ether using a crystalline aluminosilicate obtained by a new production method as a catalyst. In particular, the present invention uses as a catalyst a crystalline aluminosilicate obtained by calcining it at a high temperature or by replacing all or part of the alkali metal ions with polyvalent metal ions such as zinc or lanthanum.
The present invention also relates to a method for producing ethylene-rich lower olefins by periodically burning off carbonaceous substances deposited on a catalyst during a reaction. [Prior Art] Many natural and synthetic crystalline aluminosilicates are known as zeolites. These crystalline aluminosilicates have many pores forming a three-dimensional structure and are used as molecular sieves for adsorbents and gas separation, as well as being used industrially as catalysts for conversion of hydrocarbons. . Recently, many methods have been developed for producing lower olefins from methanol or dimethyl ether using various crystalline aluminosilicates as catalysts. For example, Mobil Oil's ZSM-5 zeolite is modified with phosphorus, manganese, calcium, etc. to produce lower olefins from methanol;
-34 zeolite (JP 53-58499) has been used to produce lower olefins from methanol. [Problems to be solved by the invention] However, although steam ZSM-5 zeolite has a large pore size and is suitable for producing gasoline, it has low selectivity for lower olefins and is therefore unsuitable for producing lower olefins. -34 Zeolite exhibits high selectivity as a catalyst for producing ethylene, propylene, etc. from methanol, but its activity deteriorates extremely quickly due to carbonaceous precipitation on the catalyst, and the degraded catalyst cannot be regenerated with air or hydrogen. However, this deterioration could not be completely removed, and it could not be said that this type of catalyst was necessarily satisfactory. [Means for Solving the Problems] The present inventors have conducted various studies in order to develop a method for efficiently producing ethylene-rich lower olefins using methanol and dimethyl ether as raw materials. A crystalline aluminosilicate of orionite nophretite zeolite obtained by the presence of a seed fixation substance in an aqueous raw material mixture containing an alkali metal salt and a choline compound is calcined at a high temperature or at least a part of its alkali metal ions are removed. By exchanging polyvalent metal ions such as zinc and lanthanum and using them as a catalyst, the target ethylene-rich lower olefin can be efficiently produced, and the carbonaceous substances deposited on the catalyst can be periodically removed. The present inventors have discovered that it is possible to stably produce lower olefins rich in ethylene by combustion removal, and have completed the present invention. The purpose of the present invention is to convert methanol or dimethyl ether into ethylene, a key raw material for petrochemicals.
The object of the present invention is to provide a method for producing lower olefins rich in ethylene, which can efficiently and stably produce lower olefins such as propylene and butene. That is, the present invention produces a solid material containing crystalline aluminosilicate by holding an aqueous raw material mixture containing a silica source, an alumina source, an alkali metal, and a choline compound under hydrothermal synthesis conditions in which the choline compound does not vaporize or split. A part of the solid material containing crystalline aluminosilicate obtained in the seed solid synthesis step is used as a seed, and this seed is added to 0.01 to 3% by weight of the following aqueous raw material mixture, silica source, alumina source, alkali metal salt, and choline. At least one of erionite and offretite-based crystalline aluminosilicate obtained from a crystalline aluminosilicate production process in which an aqueous raw material mixture containing the compound is held under hydrothermal synthesis conditions in which the choline compound does not vaporize or decompose is calcined at a high temperature. Using a catalyst in which at least a portion of the alkali metal is in the H (proton) form or at least a portion of the alkali metal is exchanged with a polyvalent metal ion, methanol and/or
or a method for producing ethylene-rich olefins, which comprises contacting the olefins with dimethyl ether. Next, the method for producing the crystalline aluminosilicate catalyst used in the present invention will be described in detail. Silica sources include silica powder, silicic acid, colloidal silica,
Dissolved silica, etc. are used, aluminum sulfates, nitrates, etc., nylium aluminate, colloidal alumina, alumina, etc. are used as alumina sources, and hydroxides of sodium, potassium, rubidium, etc. are used as alkali metal salts. As the organic additive, choline compounds such as choline chloride and choline hydroxide are used. In the seed solid synthesis step, the mother liquor gel raw material as described above is used and the choline compound is heated under hydrothermal synthesis conditions such that the choline compound does not vaporize or decompose. C. for 1 to 12 days to form a solid containing crystalline aluminosilicate. The solid obtained in this case is a low-crystalline aluminosilicate with erionite and offretite having low crystallinity. A part of the solid material containing this crystalline aluminosilicate is used as a seed in the next step, and it may be in the form of a mother liquor gel, dried product, or fired product. Next, a part of the solid material containing the crystalline aluminosilicate thus obtained is used as a seed, and an aqueous mixture containing this and the above-mentioned silica source, alumina source, alkali metal salt, and choline compound is prepared. Highly crystalline aluminosilicates of erionite and offretite zeolites are obtained by maintaining the zeolites under the same hydrothermal synthesis conditions as described above. That is, a highly crystalline aluminosilicate can be obtained by using a solid material containing low crystalline aluminosilicate as a seed. Further, the highly crystalline aluminosilicate obtained by hydrothermal synthesis as described above can be used as a seed. In any process, an amount of about 0.01 to 3% by weight of the aqueous raw material mixture based on the zeolite is sufficient.
If the amount of seed crystals is too small, a product with high purity cannot be obtained, and if it is too large, the yield will be lowered, which is not preferable. The crystalline aluminosilicate thus obtained is used as a catalyst in the method of the present invention, but it is preferable that at least a part of the exchangeable cations of the crystalline aluminosilicate are hydrogen ions (proton type). preferable. On the other hand, if the amount of hydrogen ion exchange becomes too large, the hydrogen transfer reaction becomes prominent in the methanol conversion reaction, resulting in a significant decrease in the selectivity of lower olefins, and furthermore, carbon precipitation is promoted and catalyst deterioration is accelerated.
Therefore, in the present invention, a hydrogen ion exchange amount in the range of several tens of percent is desirable. This crystalline aluminosilicate contains nitrogen compound ions in addition to alkali metal ions as part of the cations in its crystals, so in order to exchange nitrogen compound ions with hydrogen ions, the crystalline aluminosilicate must be passed through air circulation. Lower, 400-800℃,
Preferably, the crystalline aluminosilicate may be calcined at a temperature range of 500 to 600°C for 1 hour or more.Furthermore, the crystalline aluminosilicate is produced as a powder, but when used as a catalyst, it may be molded into an appropriate shape. . This molding may be carried out by a conventional method, such as extrusion molding, tablet molding, spray drying granulation, or the like. At that time, a binder or a molding aid that is normally added can be added.
For example, silica, alumina, silica, alumina,
Contains clays, graphite, stearic acid, starch, polyvinyl alcohol, etc. at 80% or less, preferably 2
It can be added in the range of ~40%. The molded product thus obtained is fired and used as a catalyst in the present invention. In addition to the above-mentioned catalysts, the catalyst used in the present invention preferably exchanges all or part of the alkali metal ions of the crystalline aluminosilicate with polyvalent ions such as zinc or lanthanum. This exchange may be carried out by a known method. For example, the crystalline aluminosilicate formed into the molded product is ion-exchanged in an aqueous solution containing ammonium ions, such as a monovalent ammonium nitrate aqueous solution, to convert it into an ammonium type, and then zinc nitrate or lanthanum nitrate is used. The gold portion or part of the alkali metal ion may be exchanged with polyvalent ions such as zinc or lanthanum by ion exchange again in an aqueous solution of . This ion exchange may be performed before making the crystalline aluminosilicate into a molded product. The process of the invention is carried out by contacting methanol and/or dimethyl ether with the crystalline aluminosilicate catalyst at elevated temperatures. The reaction method may be fixed bed, fluidized bed or moving bed, and the shape of the catalyst can be selected accordingly. The reaction temperature is 300
-500°C, preferably 350-400°C, and the pressure is not particularly limited, but it is usually in the range of 1-30 atm, preferably 1-20 atm. The raw materials methanol and/or dimethyl ether may be fed directly onto the catalyst, or a carrier gas or diluent inert to the conversion reaction of water, nitrogen, helium, carbon dioxide, hydrogen, argon, etc. or methane, ethane, propane, etc. They can be added at the same time, and it is especially preferable to add water. At this time, it is desirable that the concentration of methanol and/or dimethyl ether in the raw material is 10% or more. Furthermore, LHSV (liquid hourly space velocity) is 0.01~
30 hr ⁻¹ , preferably in the range of 0.1 to 10 hr ⁻¹ . As a reaction method, methanol may be dehydrated using a known catalyst such as γ-alumina and converted into dimethyl ether, and then passed over the aluminosilicate catalyst. Of course, there is no problem in recycling the unreacted methanol and/or dimethyl ether recovered in this conversion reaction as raw materials again. In the method of the present invention, part or all of the catalyst whose activity has decreased over time is periodically heated at 400 to 800°C in an atmosphere containing oxygen such as air.
The carbonaceous substances deposited on the catalyst are burned and removed by flowing the catalyst at high temperatures, making it possible to regenerate and reuse the catalyst. The present invention will be explained below with reference to Examples, but it is not limited to these Examples. In the Examples, all reactions were carried out under normal pressure using a fixed bed flow microreactor (10 mm x 200 mm). Example 1 Sodium aluminate (special grade Al manufactured by Wako Pure Chemical Industries)
26.76 g of Na atomic ratio 0.78), 11.95 g of sodium hydroxide (special grade manufactured by Wako Pure Chemical Industries) and 13.01 g of potassium hydroxide (special grade manufactured by Wako Pure Chemical Industries) and 266.14 g of water.
dissolved in Add 112.37g of choline chloride (special grade manufactured by Tokyo Chemical Industry Co., Ltd.) to this solution, and then add 384.43g of silica sol solution (Snowtex 30 manufactured by Nissan Chemical Industries).
were added and mixed to prepare a mother liquid gel. This mother liquor gel was placed in a Pyrex autoclave and maintained under self-generated pressure at 150°C for 8 days to convert it into zeolite. After the reaction was completed, the product was filtered and washed three times with 1 portion of distilled water each time. Then dry at 120℃ and then 550℃ in an air stream.
This gave a crystalline product (A). As a result of powder X-ray diffraction of this product, it was found to be a low erionite/offretite zeolite. Next, 3 g of the above-mentioned crystalline product (A) was added to and mixed with the mother liquor gel obtained in exactly the same manner as above, and the mixture was similarly placed in a Pyrex autoclave to undergo zeolization at 150°C under self-generated pressure.
The reaction was stopped after 8 days. Thereafter, crystal formation (B) was obtained in the same manner. X-ray diffraction analysis of this powder revealed that it was an erionite/offretite zeolite with very high crystallinity. 35% by weight of alumina binder was added to this powder to form a molded product, which was dried again and then calcined in an air stream at 550°C for 3 hours to obtain a catalyst. Fill a normal pressure flow reactor with 5 ml of this catalyst,
The methanol conversion reaction was continued for 4 hours at a reaction temperature of 350° C. and a LHSV of 1 hr ⁻¹ using raw materials to which water had been added so that the methanol concentration was 30% by weight. Table 1 shows the reaction results up to 4 hours from the start of the reaction. Example 2 1 g of the catalyst produced in Example 1 was subjected to natural reflux for 2 hours in 5 ml of a 2.2N ammonium nitrate aqueous solution, which was repeated 4 times to obtain a mono-supported ammonium type. After that, it is dried and a 1N aqueous solution of zinc nitrate is
ml at 88°C for 4 hours to perform ion exchange into zinc form. This catalyst was dried and then calcined to carry out the same reaction as in Example 1. The results are shown in Table-1. Example 3 The same procedure as in Example 2 was carried out except that zinc nitrate in Example 2 was changed to lanthanum nitrate, and the reaction results are shown in the table.
Shown in 1. Examples 4 to 7 Air was blown into the spent catalyst of Example 1 at 550°C.
The gas was introduced at a rate of 20 ml/min, and the calcination was continued until carbon dioxide was no longer observed in the gas flowing out from the reaction tube.
Next, after sufficiently purging oxygen with nitrogen gas, Example 1
The reaction was carried out under the same conditions as above, and the same operation was repeated three times. The results of these reactions are shown in Table-1. Comparative example 1 Sodium aluminate (special grade Al manufactured by Wako Pure Chemical Industries)
26.76 g of Na atomic ratio 0.78), 11.95 g of sodium hydroxide (special grade manufactured by Wako Pure Chemical Industries) and 13.01 g of potassium hydroxide (special grade manufactured by Wako Pure Chemical Industries) in 266.14 g of water
Dissolved in g. To this solution, 112.37 g of choline chloride (special grade manufactured by Tokyo Chemical Industry Co., Ltd.) was added, and then 384.43 g of silica sol solution (Snowtex 30 manufactured by Nissan Chemical Industries) was added.
g was added and mixed to prepare a mother liquid gel. This mother liquor gel was placed in a Pyrex autoclave and maintained under self-generated pressure at 150°C for 8 days to convert it into zeolite. After the reaction was completed, the product was filtered and washed three times with 1 portion of distilled water each time. Then dry at 120℃ and then 550℃ in an air stream.
The mixture was calcined for 3 hours to obtain a crystalline product (A). As a result of powder X-ray diffraction of this product, it was found to be a low erionite/offretite zeolite. This crystalline aluminosilicate was catalyzed and reacted in the same manner as in Example 1. The results are shown in Table-2. Comparative Example 2 Highly crystalline aluminosilicate was obtained by performing the same operation as in Comparative Example 1 except that the zeolization temperature was 180°C and the zeolization time was 6 hours. Catalytic reaction was carried out in the same manner as in Example 1. Table 2 of the results
Shown below. Comparative Example 3 The catalyst obtained in Comparative Example 2 was subjected to the same operation as in Example 3 to form a lanthanum type catalyst and a reaction was carried out. The results are shown in Table-2. Comparative Example 4 The zeolization temperature and time of Comparative Example 1 were 180
C. for 8 hours and the organic additive was changed to tetramethylammonium, but the same operation as in Comparative Example 1 was carried out to obtain a highly crystalline aluminosilicate.
This highly crystalline aluminosilicate was catalyzed and reacted in the same manner as in Example 1. The results are shown in Table-2.

[Table] *2 Total of ethylene, propylene, butene

〔Effect of the invention〕

As is clear from the above results, when the present invention is used, it is possible to convert methanol into ethylene at a high conversion rate.
Lower olefins such as propylene and butene can be obtained. Moreover, this also applies when dimethyl ether is used instead of methanol.

Claims (1)

[Claims] 1. A solid containing crystalline aluminosilicate is produced by holding an aqueous raw material mixture containing a silica source, an alumina source, an alkali metal salt, and a choline compound under hydrothermal synthesis conditions in which the choline compound does not vaporize or decompose. A part of the solid material containing crystalline aluminosilicate obtained in the seed solid synthesis process is used as a seed, and this seed is used as a seed for the following aqueous raw material mixture.
Erio obtained from a crystalline aluminosilicate manufacturing process in which an aqueous raw material mixture containing 0.01 to 3% by weight, a silica source, an alumina source, an alkali metal salt, and a choline compound is held under hydrothermal synthesis conditions in which the choline compound does not vaporize or decompose. Night and offretite crystalline aluminosilicate is calcined at high temperature to convert at least a part of it into the H (proton) form, or at least a part of its alkali metal is exchanged with polyvalent metal ions, using as a catalyst, 1. A method for producing ethylene-rich olefins, which comprises contacting them with methanol and/or dimethyl ether at high temperature and normal pressure to high pressure. 2. The crystalline aluminosilicate manufacturing process includes at least two steps, and only the first step uses as a seed a part of the solid material containing the crystalline aluminosilicate obtained in the seed solid material synthesis step. The method for producing ethylene-rich olefins according to claim 1, wherein a part of the crystalline aluminosilicate-containing solid material obtained in the production process is subsequently used as a seed for the production process. 3. The method for producing ethylene-rich olefins according to claim 1 or 2, characterized in that the carbonaceous material deposited as a catalyst by the catalytic reaction is periodically burned and removed. 4. The crystalline aluminosilicate production process includes at least two steps, and only the first step uses a part of the solid material containing the crystalline aluminosilicate obtained in the solid material synthesis step as a seed, and the subsequent steps include Ethylene-rich olefins according to any one of claims 1 to 3, in which a part of the solid material containing crystalline aluminosilicate obtained in the manufacturing process is used as a seed in the manufacturing process. manufacturing method.