JPH0672111B2 - Propylene production method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention In the present invention, a butane-butene fraction (referred to as BB ′ fraction) obtained from a catalytic cracking apparatus, a thermal cracking apparatus or the like is heated and contacted with a dealkalized zeolite catalyst. The present invention relates to a method for producing propylene by

<Technical Background of the Invention and its Problems> In an oil refinery, a large amount of cracked gas containing olefin is produced as a by-product from a fluid catalytic cracking apparatus and a thermal cracking apparatus.

Propane and butane are used as household fuels, and propylene is widely used as a petrochemical raw material. However, mixed butenes are not preferable as a household fuel because they have poor storage stability and have a bad odor.

One of the uses of mixed butenes is the disproportionation reaction to propylene, and the catalyst is cobalt molybdate or Re ₂ O ₇
/ Al ₂ O ₃ is used. This reaction is also called metathesis, and the reaction mechanism is not yet clear, but formally 2 mol of butene and 1 mol of propylene and 1 mol of pentene are formed. Therefore, the theoretical maximum yield of propylene is 50
It is as low as mol% (37.5 wt%) and has a drawback that the actual yield can be suppressed to a value lower than this.

<Purpose of the Invention> The present invention has been made to solve such a conventional drawback, and one of the effective utilization methods of BB 'fraction is BB'.
The purpose is to convert butenes in a fraction into propylene with good selectivity.

<Summary of the Invention> That is, according to the present invention, a butane-butene fraction containing at least 10% by weight or more is heated and contacted with a catalyst containing a dealkalized zeolite, aluminum fluoride and a metal having a weak hydrogenating ability. The present invention relates to a method for producing propylene.

Examples of the first component zeolite used as the base material of the catalyst of the present invention include porphyrite, gmelinite, zeolite L, model night, zeolite 0, zeolite X, zeolite Y, ferrierite, ZSM-5, ZSM-11,
Examples include clinoptiolite, but especially ZSM-5, Z
SM-11, mordenite, zeolite Y and phosjasite are preferably used.

The zeolite has a particle size of 0.01 to 1000μ, preferably 0.1 to 100
It is used in a powdery or granular form of μ.

The conversion reaction of the BB 'fraction to propylene in the present invention is an acid-catalyzed reaction. Therefore, in order to use the above zeolite as the catalyst of the method of the present invention, it is necessary to dealkalize with an acid or an ammonium salt to reduce the proportion of alkali in the zeolite.

The dealkalization ratio is preferably 50 mol% or more of the alkali metal or alkaline earth metal contained in the zeolite, and particularly preferably 90 mol% or more. In this case, examples of the dealkalizing agent include mineral acids such as hydrochloric acid, sulfuric acid, nitric acid and phosphoric acid, and water-soluble organic acids such as formic acid, acetic acid and malic acid, and salts containing ammonium ions such as ammonium chloride and ammonium nitrate. However, these acids or salts may be used alone or in combination. Among them, hydrochloric acid, nitric acid, ammonium chloride,
Ammonium nitrate and the like are preferable. These acids or salts are used in the form of an aqueous solution. The acid concentration in that case varies depending on the treatment conditions, but it is preferably 1 to 6 N, and when an ammonium salt is used, the concentration is 1 to 30%, particularly 5 to 15%. The treatment temperature may be room temperature, but in order to shorten the treatment time, heating to 80-100 ° C is preferable. Since the treatment time depends on the temperature and cannot be generally stated, it is generally preferably 5 hours to 3 days.

The second component, aluminum fluoride, used as the base material of the catalyst of the present invention is, for example, E. Band Ann.Chim.Phys., (8)
1, 60 (1904), A Mazzuchelli, Atti Accad Lincei,
(5) 16i, 775 (1907), WFFhrot, FTFroro, J.Am.C
hem.Soc., 6674 (1945) and the like, aluminum trifluoride hydrate or JM. Cowley, TR. Scott, J. Am.
Chem.Soc, 70, 105 (1948); RLJohnson, B. Siegel Natu
Basic aluminum fluoride prepared by the method of Re 210, 1256 (1966) is preferred.

In particular _{α-AlF 3 · 3H 2 O} , β-AlF 3 · 3H 2 O and these 700 ° C. temperature below, preferably Hutu aluminum obtained by firing at 200 to 500 ° C. are preferably used. Further, similarly effective aluminum fluorides can also be obtained by passing an excess of anhydrous hydrogen fluoride at a temperature of 200 to 500 ° C. in a reaction tube filled with alumina, aluminum hydroxide and a mixture thereof. It can also be obtained by passing an excess of anhydrous hydrogen fluoride at 20 to 400 ° C in a reaction tube filled with aluminum. When these aluminum fluorides are prepared as components of the catalyst of the method of the present invention, it is not necessary to prepare them purely for use, and those obtained as a mixture thereof are sufficient.

The metal of the third component used as the base material of the catalyst of the present invention is a metal having a weak hydrogenation ability, and at least one metal selected from these metal groups is used. These metals include silver, copper, zinc, chromium, iron, cobalt, manganese, cadmium, tin, zirconium, molybdenum,
Tungsten etc. can be illustrated.

The catalyst used in the present invention is usually washed with water after acid treatment,
After mixing dealkalized zeolite dried at 50 to 200 ° C for 0.5 to 8 hours with aluminum fluoride, powdered or granular (1 to
5 mmφ) or the like, for example, by compression molding or the like, and baked at 100 to 700 ° C., preferably 300 to 600 ° C.

Then, it can be obtained by supporting at least one metal component selected from the group of metals having a weak hydrogenating ability by a conventional method such as an ion exchange method or an immersion method. The metal component may be loaded on each of them before the dealkalized zeolite and aluminum fluoride are mixed.

The above-mentioned firing is normally performed in air, but it is of course possible to perform it in an inert gas such as nitrogen or carbon dioxide or hydrogen gas.

The composition ratio of the catalyst used in the method of the present invention varies depending on the reaction conditions, but the dealkalized zeolite is usually 20 to 99 wt.
%, Preferably 40 to 90 wt%, aluminum fluoride is 1 to
80 wt%, preferably 10-60 wt%, the content of the metal component having a weak hydrogenation capacity is 0.05-30 wt%, preferably 1-10
wt%.

As described above, the catalyst used in the present invention is required to have three components as essential components, and as shown in Examples below, it is possible to effectively carry out a preferable reaction even if any one component is missing. I can't.

The raw material used in the present invention is, for example, in a petroleum refining plant, in the presence of a catalyst, from kerosene to a heavy fraction, mainly decompressed gas oil is decomposed to produce a high octane number gasoline. BB 'fraction, which is a by-product from a thermal cracker that decomposes petroleum fraction to make it lighter by
Particularly, the BB 'fraction containing at least 10% by weight of butene is used.

The conversion reaction of the present invention is carried out in a gas phase under 100% raw material or various gas atmospheres. Examples of the atmosphere gas include hydrocarbon gas, nitrogen, steam, hydrogen, carbon dioxide and the like, but hydrogen is particularly preferably used.

In the present invention, the conversion reaction is preferably accomplished in the presence of hydrogen gas. Hydrogen mainly has the effect of reducing the amount of carbonaceous deposits. The amount of hydrogen added to the BB ′ fraction is not particularly limited, but a BB ′ fraction: hydrogen molar ratio of 1:50 or less is sufficient, and a range of 1: 1 to 1: 5 is particularly preferable.

Since the catalyst of the present invention has an extremely high conversion activity of the BB 'fraction, the reaction proceeds even at normal pressure, but it is industrially preferable to operate under pressure, and the reaction pressure is 100 atm or less, particularly 20 atm.
Around atmospheric pressure is appropriate. The reaction temperature is preferably 250-500 ° C,
Especially 300-450 ℃ is good. There is no particular limitation on the feed methanol supply rate WHSV (g-feed gas / g-cat-hr) per unit weight of catalyst, but 10 or less is preferable to obtain a high conversion rate, and the range of 0.5 to 2.0 is particularly preferable. It is suitable.

The conversion reaction of the present invention can be carried out by a heretofore known fixed bed, fluidized bed or other method, but the fixed bed gas phase reaction is optimal in view of easiness of operation and the like.

<Effects of the Invention> The catalyst used in the present invention has high selectivity in the conversion reaction of butene to propylene, and has a higher propylene yield than conventional metathesis catalysts.

<Examples of the Invention> The method of the present invention will be described in detail below with reference to specific examples.

Example 1 ZSM-5 Na type was calcined at 500 ° C. for 5 hours and then acid-treated with 2N hydrochloric acid at a temperature of 90 to 100 ° C. for 5 hours. sufficient,
It was washed with water and then dried at 120 ° C. for 5 hours to obtain dealkalized ZSM-5 (catalyst A).

20 wt% of aluminum trifluoride was added to and mixed with the acid-treated catalyst, compression-molded into pellets of 3 × 4 mmφ, and calcined at 500 ° C. for 8 hours (catalyst B).

An aqueous solution of silver nitrate was immersed in each of the catalysts A and B so as to have a metal silver content of 5% by weight, dried at 120 ° C. for 5 hours, and calcined at 500 ° C. for 5 hours to obtain catalysts C and D, respectively.

Using 2.0 g of the catalyst thus obtained, a temperature of 470
° C, flow rate of hydrogen 4.2l / hr, flow rate of BB 'fraction gas 2.0g / h
r, therefore the molar ratio of hydrogen and BB 'fraction = 3.0, WHSV = 1
An experiment of conversion reaction of BB 'fraction to propylene was carried out under normal pressure for hr ^-1 .

The results are shown in Table 1.

Catalyst system D consisting of 3 components: ZSM-5, aluminum fluoride and silver
Has a propylene yield higher than the theoretical maximum yield of propylene in butene metathesis of 37.5 wt%, and 1
Alternatively, it has an excellent selectivity to propylene as compared with the two-component catalysts A, B and C.

Example 2 Na type mordenite was calcined at 500 ° C. for 5 hours and then acid-treated with 2N hydrochloric acid at a temperature of 90 to 100 ° C. for 5 hours.
It was thoroughly washed with water and then dried at 120 ° C. for 5 hours to obtain dealkalized mordenite (catalyst E).

20 wt% of aluminum trifluoride was inversion-mixed with the acid-treated catalyst, compression-molded into a pellet of 3 × 4 mmφ, and calcined at 500 ° C. for 8 hours (catalyst F).

An aqueous silver nitrate solution was immersed in the catalysts E and F so as to have a metal silver content of 5 wt%, dried at 120 ° C. for 5 hours and calcined at 500 ° C. for 5 hours to obtain catalysts G and H, respectively.

Using 2 g of the catalyst thus obtained, a conversion reaction experiment of the BB 'fraction to propylene was conducted under the same reaction conditions as in Example-1.

The results are shown in Table 2.

The catalyst system H consisting of the three components of mordenite, aluminum fluoride and silver has a higher propylene yield than the theoretical maximum yield of propylene in butene metathesis of 37.5 wt%,
Moreover, it has excellent selectivity to propylene as compared with the one- or two-component catalysts E, F, and G.

Example 3 Zinc nitrate or an aqueous solution of copper nitrate was soaked in the catalyst B in Example 1 so as to be 5 wt% as metallic copper or metallic zinc, dried at 120 ° C. for 5 hours, and calcined at 500 ° C. for 5 hours. Zinc-supported catalyst I and copper-supported catalyst J were obtained, respectively.

Example 1 using 2.0 gr of the catalyst thus obtained
The conversion reaction experiment of BB 'fraction to propylene was carried out under the same reaction conditions as above.

The results are shown in Table 3.

The catalysts I and J using zinc or copper instead of silver in the three-component catalyst D of Example 1 have a propylene yield higher than the theoretical maximum yield of 37.5 wt% in metathesis of butene, and convert butene to propylene. It can be seen that it is an excellent catalyst that

Claims (3)

[Claims] 1. A butane-butene fraction containing at least 10% by weight of butene is heated and brought into contact with a catalyst containing a dealkalized zeolite, aluminum fluoride and a metal having a weak hydrogenating ability. And a method for producing propylene. 2. The method for producing propylene according to claim 1, wherein the zeolite is ZSM-5, ZSM-11, mordenite, Y-type or phosjasite. 3. The method for producing propylene according to claim 1, wherein the reaction is carried out in the presence of hydrogen.