JPS5940365B2 - Method for producing olefin - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing olefins using methanol and/or dimethyl ether as raw materials.

Lower olefins such as ethylene, propylene, and butene, and aromatic compounds such as xylene are key intermediate raw materials in the petrochemical industry, and are currently produced by pyrolysis from petroleum-based raw materials such as natural gas and naphtha.

However, due to the recent rise in prices and difficulty in obtaining these petroleum-based raw materials, it is desired to diversify raw materials for producing lower olefins and xylene. On the other hand, in the production of methanol or dimethyl ether, these raw materials are not limited to petroleum-based raw materials, and can be produced inexpensively from coal and the like. Furthermore, it is already known that mixtures of various olefins, paraffins and aromatic compounds can be obtained by contacting methanol and/or dimethyl ether with various zeolite catalysts at temperatures above 260°C, and various methods have been developed. ,Proposed. The present inventors have also carried out extensive studies on the crystallization of zeolite, and have found that a new zeolite with a unique crystal form can be obtained by crystallizing it in the coexistence of fluorine ions (Japanese Patent Application No. 166696/1989). (Japanese Patent Publication No. 58-1045), and that this crystal exhibits a suitable catalytic action for the reaction of obtaining olefins from methanol and/or dimethyl ether (Japanese Patent Application No. 55-39581, Japanese Patent Publication No. 5740124). . When trying to produce ethylene and propylene from methanol and/or dimethyl ether using crystalline aluminosilicate zeolite catalysts, conventionally proposed methods use relatively inert substances such as water and nitrogen as reaction diluents. Attempts are being made to increase the selectivity of ethylene and propylene by significantly lowering the partial pressure of methanol and/or dimethyl ether by using large amounts (for example, Japanese Patent Laid-Open No. 122003/1983).

When reacting at a reaction pressure of 1 atm, when methanol is used, the partial pressure is diluted to about 0.35 atm, and dimethyl ether is diluted to about 0.18 atm. Although this method achieves a result in which the deterioration of the catalyst activity over time is sufficiently small, on the other hand, a large amount of energy is required for preheating the raw material mixture and separating the target substance from the reaction product at the reactor outlet. On the other hand, when the partial pressure of methanol and/or dimethyl ether is significantly high, especially when the reaction is carried out without using any diluent, the catalyst activity deteriorates over time under normal catalyst loading conditions and normal liquid time-space velocity conditions. However, this method had the disadvantage that it became considerably large and the frequency of catalyst regeneration increased.
Therefore, if ethylene and propylene can be produced from methanol and/or dimethyl ether using less diluent, with high reaction rate and high selectivity, and with sufficiently minimizing deterioration of catalyst activity over time, it is possible to preheat the raw material mixture. The present invention has also made it possible to save energy in the reaction product purification system, which is very attractive from an industrial perspective.The present inventors have therefore conducted intensive studies on reaction conditions in which almost no diluent is used. As a result of extensive studies on reaction conditions in the production of olefins from methanol and/or dimethyl ether, the present inventors found that the amount of reaction heat generated per unit time per unit cross-sectional area of the catalyst layer perpendicular to the flow direction of the raw material supply. It has been found that by reducing the amount of diluent used, it is possible to maintain high reaction rate and high selectivity even though the amount of diluent used is reduced, and to significantly reduce the deterioration of catalyst activity over time.

The object of the present invention is to be able to obtain industrially important olefins, especially lower olefins such as ethylene and propylene, from methanol and/or dimethyl ether with high reaction rate and high selectivity, and to minimize deterioration of the catalyst over time during production. , and to provide an industrially advantageous production method that eliminates the drawbacks caused by diluting methanol and/or dimethyl ether with a large amount of diluent in the reaction system, making it possible to save energy.

That is, the present invention uses a fixed bed catalyst reactor to produce olefins from methanol and/or dimethyl ether using a catalyst containing crystalline aluminosilicate zeolite, and the silica/alumina molar ratio is 5.
0 or more, has the following interplanar spacing and relative strength in an X-ray diffraction diagram, and contains or does not contain fluorine. Using a catalyst containing a crystalline aluminosilicate,
A method for producing olefins, characterized in that methanol and/or dimethyl ether is supplied at a rate of 0.3 to 157 per second per 1 m'' of cross-sectional area of the catalyst layer, and the amount of diluent used is reduced, provided that the lattice spacing is 10 It shows the strongest intensity at .0λ or 3.84λ.

The feed rate of methanol and/or dimethyl ether in the present invention is extremely low compared to conventional methods.

For example, if no diluent is used, the cross-sectional area of the catalyst is 1T.
Methanol supply amount per second per I 0.3-157
This means that the methanol gas linear velocity (L■) is approximately 0.02 to 1.05? /See (standard state). In addition, the dimethyl ether supply amount is 0.3 to 15 y/y.
Sec means a value of about 0.02 to 0.73 CTn/Sec (standard state) as dimethyl ether gas linear velocity. In the case of a normal fixed bed catalytic reactor, this is
The gas linear velocity is at least 5CTI1/Sec or higher, and generally several tens of seconds? This is extremely small compared to what is done above /Sec. If the supply amount is outside this range, the catalyst activity will deteriorate significantly over time. In addition, in order to obtain a high space-time yield that is industrially advantageous, the feed rate of methanol and/or dimethyl ether should be 0.05 to 301 liquid per hour (liquid hourly space velocity LSVHO) to the catalyst 11.
．． It is preferable to set it as O5-30/Hr).

In order to achieve the above-mentioned linear velocity and liquid space velocity, the thickness of the catalyst packed bed must necessarily be made thin, but the thickness can be appropriately determined by calculation or experiment.

The crystalline aluminosilicate zeolite used in the present invention is a new zeolite (hereinafter referred to as FZ-1 zeolite) that has a unique crystal form obtained by crystallization in the coexistence of fluorine ions, which the present inventors previously invented. ).

The FZ-1 zeolite is a crystalline aluminosilicate that has the following interplanar spacing and relative strength in an X-ray diffraction diagram, and that may or may not contain fluorine, compared to the crystals of conventional ZSM-5. Only specific crystal faces have a unique crystal shape that has been specially grown. However, the strongest strength is exhibited when the interplanar spacing is 10.0λ or 3.84λ.

The X-ray diffraction lines here are obtained using a commercially available X-ray diffractometer, such as a self-recording X-ray recording type X-ray diffractometer Geigerflex DS model manufactured by Rigaku Corporation, using a standard powder diffraction method. It was measured using radiation of Kα of copper, and from the 2θ obtained in this measurement, the interplanar spacing (unit: λ
). Note that measurement methods other than those described above can be used. The method for synthesizing this FZ-1 zeolite is explained in the specification of Japanese Patent Application No. 54166696, and the method for activating it as a catalyst is explained in the specification of Japanese Patent Application No. 55-39581.

That is, silicon and aluminum compounds were heated in an aqueous solution containing an organic cation and an alkali compound in the coexistence of fluorine ions at a heating temperature of 1° C./min or more, and
It is obtained by hydrothermal synthesis at a temperature range of -200°C, preferably 130-170°C, usually under autogenous pressure for a period of 4-150 hours.

Prior to hydrothermal synthesis, it is preferable to mix the raw material mixture in such a way as to generate a shearing force such that the linear velocity at the tip of the edge of the rotating portion is 10 m/sec or more. Note that as raw materials other than fluorine ions in this hydrothermal synthesis, substances used in ordinary hydrothermal synthesis of zeolite can be used. That is, silicon is, for example, sodium silicate, solid silica, silica gel, and silica sol, and aluminum compounds are, for example, sodium aluminate and freshly prepared aluminum hydroxide. Typical examples of organic cations include quaternary ammonium ions such as tetramethylammonium, tetraethylammonium, and tetrapropylammonium. Tetraethylammonium and tetrapropylammonium chloride can be used, and tertiary amines such as trimethylamine and triethylamine can be used in combination with methyl bromide and methyl alcohol. Examples of alkaline compounds include sodium compounds such as caustic soda. Note that sodium aluminate also acts as an alkaline compound. As a fluorine ion source, for example, soda fluoride, ammonium fluoride, boron fluoride, etc. can be used.

The molar ratio of the raw materials is as follows.

Commercially available silica gel usually contains about 1000 ppm Al2O.
The crystalline aluminosilicate used in the present invention can be obtained using only this aluminum oxide without adding any other aluminum compound.

The molar ratio of SiO2/Al2O3 in the raw material mixture is
This is almost the same as the SiO2/Al2O3 molar ratio in the crystalline aluminosilicate used in the present invention.

The reaction product is cooled to room temperature, filtered, washed with water, and the crystals are separated to obtain FZ-1 zeolite.

Further, this FZ-1 zeolite is dried at, for example, 100°C or higher for 1 to 30 hours, and then dried at 350 to 800°C, preferably 400 to 600°C, for 2 to 24 hours, preferably 4 to 30°C.
Bake for 10 hours. When calcined outside this temperature range, the catalyst activity becomes relatively low. Thereafter, acidic solutions of inorganic acids such as hydrochloric acid, sulfuric acid and nitric acid and organic acids such as formic acid, oxalic acid, acetic acid and citric acid or mixed acid solutions thereof, most preferably 1-22 wt% hydrochloric acid and 10-12 wt%
At 0°C, preferably 40-100°C, for 0.1-30 hours,
Preferably, it is activated as an acid catalyst by contacting for 1 to 10 hours. The FZ-1 zeolite activated in this way can be calcined as desired. The H+ type FZ-1 zeolite obtained in this way is used as a catalyst in X, but some or all of the H+ ions are ion-exchanged with at least one other cation by a normal ion exchange operation. It can also be used. Ion-exchanged FZ-1 zeolite usually has improved heat resistance. In the case of ion exchange, monovalent alkali metal ions such as lithium, sodium, potassium and cesium, divalent alkaline earth metal ions such as magnesium, calcium, strontium and barium, lanthanum and cerium are used as ion-exchangeable cations. Trivalent rare earth ions such as trivalent rare earth ions, 4 such as thorium
Valid ions and other cations such as ammonium, manganese, iron, cobalt, nickel, zinc, copper and aluminum can be used. Among these, rare earth ions are particularly preferred. In the ion exchange operation, the H+ type FZ-1 zeolite and a mixture of an aqueous solution containing the desired cation or a compound containing the desired cation and a non-aqueous medium are mixed in either a batch or continuous manner. This can be achieved by touching the object. The FZ-1 zeolite ion-exchanged in this manner may be calcined. Catalysts containing FZ-1 zeolite may be in a variety of forms, including fine powders, pellets, tablets, and extrudates. Also commonly used as binders for zeolite catalysts are clays, alumina,
It can be mixed with refractory inorganic oxides such as silica, silica-alumina, and titania, and molded by wet molding or dry molding. In this case, the binder content is preferably in the range of 1 to 99 wt%, preferably 10 to 80 wt%. Furthermore, ligninsulfonic acid, stearic acid, starch, polyvinyl alcohol, crystalline cellulose, etc. may be added to these binders for molding. The FZ-1 zeolite molded in this manner can be fired as desired. Calcination after acid treatment often improves catalyst activity.

The firing conditions after this acid treatment are practically 250 to 800℃.
The temperature is preferably 300 to 600°C for 0.5 to 10 hours, preferably 1 to 5 hours. In the present invention, the raw material is methanol and/or dimethyl ether.

When methanol is used as a raw material, olefins can be obtained all at once by bringing the methanol into direct contact with the catalyst of the present invention.
The method of the present invention can be applied to dimethyl ether, which is first converted into dimethyl ether by contacting with a conventional dehydration catalyst such as an alumina catalyst. In the latter case, the heat generated by the reaction is divided into two parts, which has the advantage of making it easier to control the temperature of the catalyst bed. Furthermore, methanol and dimethyl ether can each be used as a mixture with an alcohol having two or more carbon atoms.

In this case, the amount of alcohol having 2 or more carbon atoms is 3 to the amount of methanol and/or dimethyl ether.
It is preferably 0 wt% or less. The reaction temperature is practically 250°C or higher, preferably 250 to 550°C, but
It can be appropriately selected depending on the target substance.

That is, in order to obtain an olefin with a large number of carbon atoms, a relatively high temperature is preferable; for example, in order to increase the selectivity of ethylene, a temperature of 300 to 400°C is preferable, and in order to increase the selectivity of propylene, a temperature of 400 to 500°C is preferable. 250
If the temperature is lower than ℃, the reaction rate will be low.

In the present invention, by reducing the feed rate of methanol and/or dimethyl ether, it is possible to reduce the amount of diluent used, and although there is essentially no need to use diluent at all, the amount used conventionally is Much smaller amounts of diluent can be used.

For example, if the total pressure is 1 atm, methanol and/or
Alternatively, the partial pressure of dimethyl ether may be 0.4 to 1 atm. As the diluent, diluents commonly used in this reaction, such as nitrogen, hydrogen, carbon monoxide, carbon dioxide, alkanes, and water, are preferably used. In the present invention, if the reaction is carried out in a fixed bed catalytic reactor and reaction conditions are selected such that methanol and/or dimethyl ether are insufficiently converted, unreacted raw materials are separated from the reaction products. can be circulated.

The method of the present invention uses a catalyst containing crystalline aluminosilicate zeolite, particularly preferably FZ-1 zeolite, as an active ingredient, and uses inexpensive and easily available methanol and/or dimethyl ether as a raw material to produce industrially important ethylene. It is an industrially advantageous olefin production method because it can obtain propylene, butene, and varaxylenes with high reaction rate and high selectivity, has a long catalyst life, and can significantly reduce the amount of diluent used. be.

The present invention will be explained in more detail below by giving examples.
Example 1 Catalyst: 0.127 ml of sodium aluminate (containing 34.9 wt% and 33.3 wt% as Al2O3 and Na2O, respectively), 1.5 y of caustic soda and 0.807 ml of ammonium fluoride were dissolved in 1857 ml of water.

14.2 y of tetrapropylammonium bromide was added to this to form a uniform aqueous solution. Further, 28.57% of 40 Wt% silica sol was added to this aqueous solution, and the entire mixture was put into a mixer and heated at 10,000 r.p.m. p. The mixture was mixed for 3 minutes at room temperature at a rotational speed of m (linear velocity of the blade tip: 45 m/sec).
After that, put this raw material mixture into a corrosion-resistant pressure container 153
The temperature was raised to 0.degree. C. in 1 hour and maintained under autogenous pressure for 60 hours. Then, the reaction product is cooled, and the resulting crystals are collected,
After washing the crystals with water until the washing solution becomes neutral, the crystals were heated at 110°C.
It was dried for 10 hours. The molar ratio between raw materials is SlO2/A
l2O3-474, B4N+/SiO2O. 28 (R is a propyl group), Na+/SiO2O. 22, F-/Sl
O2-0.11. It was set as H20/SiO259.3. The size of the crystal was 64μ×20μ, and the fluorine content of the crystal was 0.3wt%. The X-ray diffraction data of the obtained crystals were as shown in Table-1. The thus obtained FZ-
1 Zeolite powder was calcined in air at 550°C for 5 hours,
Thereafter, it was treated with an 18 wt % aqueous hydrochloric acid solution at 90°C for 5 hours, then cooled, separated, washed with water until no chlorine ions were detected in the washing solution, and then dried at 110°C for 10 hours.

20wt% in this H+ type crystalline aluminosilicate powder.
After adding silica sol and kneading well, 3mmφ×3mmH
It was molded using a perforated plate. After drying, the molded body was taken out from the perforated plate and calcined in air at 550°C for 5 hours to obtain a catalyst. This catalyst contained 80 wt% aluminosilicate and 20 wt% silica as a carrier. Reaction: 4.4 ml of the catalyst containing the above FZ-1 zeolite was packed into a reaction tube with a cross-sectional area of 7.3 cr, and the filling height was set to 0.6 (V
7! And so.

A methanol feed rate (LSVH) of 2.1/h1- was applied to a catalyst bed maintained at 355°C under normal pressure without a diluent.
Methanol was passed through.

The amount of methanol supplied per second per 1 d of cross-sectional area is 2.7
y, and the methanol gas linear velocity is 0.19 (711/
Figure 1 shows the time course of the reaction results at Sec.
Comparative Example 1 3.4 m1 of the same catalyst as Example 1 with a cross-sectional area of 0.83 cd
The reaction tube was filled to a filling height of 4.1CTI1.

Methanol was passed through the catalyst bed maintained at 355°C under normal pressure without diluent at a methanol feed rate (LSVH) of 2.2/Hr.

The amount of methanol supplied per second per cross-sectional area is 207
and the methanol gas linear velocity is 1.4Cr1L/Se
It was c. Figure 1 shows a comparison of the reaction results over time. As shown in FIG. 1, in Example 1, both the methanol reaction rate and the hydrocarbon selectivity maintained high values for a long time compared to the comparative example, indicating that the catalyst activity of the present invention was less likely to decrease. It shows. Example 2 The same catalyst as Example 1, 4.6 m1, with a cross-sectional area of 4.4 cr!
The reaction tube No. i was filled with the mixture, and the filling height was set to 1.0 CTIL.

Methanol was passed through the catalyst bed maintained at 355° C. under normal pressure without diluent at a methanol feed rate (LSVH) of 1.2/Hr.

The methanol supply rate is 2.77 per second per 1 m of cross-sectional area, and the methanol gas linear velocity is 0.19 (11/S
It was ec. The reaction results are shown below. Comparative Example 2 A catalyst was prepared in the same manner as in Example 1, except that no fluorine compound was added.

The size of the obtained crystal is 2μ×2μ, and the crystal size is
The line diffraction data were as shown in Table 2. This is ZSM-
This is consistent with the X-ray diffraction data of 5 zeolite. 4.6 ml of the prepared catalyst was packed into a reaction tube with a cross-sectional area of 4.4 cd,
Methanol was supplied and reacted in the same manner as in Example 2.

The reaction results 20111-years after the start of the reaction are shown below. In Comparative Example 2, the total lower olefin content of ethylene + propylene + butene in the catalyst made of ZSM-5 zeolite equivalent was 23%, compared to 43% in the case of the catalyst made of FZ-1 zeolite in Example 2. This shows that it is very low.

Example 3 A catalyst 4.4me similar to Example 1 was used with a cross-sectional area of 7.
A 3 cd reaction tube was filled, and the filling height was set to 0.6 cm.

Methanol was passed through the catalyst bed maintained at 335° C. under normal pressure and without diluent at a methanol feed rate (LHSV) of 1.2/Hr.

The amount of methanol supplied per second per 1 m2 of cross-sectional area is 1,
6y and methanol gas linear velocity is 0.11CT! L/
It was Sec. The reaction results are shown below. Example 4 The reaction was carried out under the same conditions as in Example 3, except that water was used as a diluent and the methanol partial pressure was 0.63 atm.

The reaction results are shown below. In Example 3, in which the reaction was carried out without using any diluent, the ethylene selectivity was slightly low until about 20 hours from the start of the reaction, but in this Example, in which a small amount of water was used as a diluent, the ethylene selectivity was slightly low. The advantage of this method was that it showed high ethylene selectivity from the beginning of the reaction.

Example 5 6.2 ml of the same FZ-1 zeolite catalyst as in Example 1 was packed into a reaction tube with a cross-sectional area of 13.3 crii, and the filling height was set to 0.47 cTn.

A dimethyl ether feed rate (WHS■) of 0.77/l) J was added to the catalyst bed kept at 335°C under normal pressure and without diluent.
- passed through dimethyl ether.

The dimethyl ether supply amount per second per 1 m'' cross-sectional area is 0.827, and the dimethyl ether gas linear velocity is 0.
．． 04? /Sec. The reaction results are shown below. centre

[Brief explanation of the drawing]

FIG. 1 is a graph showing changes over time in methanol reaction rate, hydrocarbon selectivity, and ethylene selectivity in hydrocarbons.

Claims (1)

[Claims] 1. When producing olefins from methanol and/or dimethyl ether using a fixed bed catalyst reactor using a catalyst containing crystalline aluminosilicate zeolite, the molar ratio of silica/alumina is 50 or more. ,
Using a catalyst containing crystalline aluminosilicate that has the following interplanar spacing and relative strength in the X-ray diffraction diagram and that contains or does not contain fluorine, methanol and/or dimethyl ether are mixed with a catalyst layer cross-sectional area of 1 m^ 1. A method for producing olefin, characterized in that the amount of diluent used is reduced by supplying a diluent in the range of 0.3 to 15 g per second per second. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ However, the strength is strongest when the interplanar spacing is 10.0 Å or 3.84 Å.