JPH0466918B2 - - Google Patents

Description

[Detailed description of the invention]

<Technical Field of the Invention> The present invention relates to a method for producing high octane gasoline by heating and contacting a raw material gas containing an olefin gas having 2 to 5 carbon atoms with a zeolite catalyst. <Technical background of the invention and its problems> In petroleum refineries, a large amount of cracked gas consisting of paraffin and olefin having 1 to 5 carbon atoms is produced as a by-product from fluid catalytic crackers, thermal crackers, and the like. Of these, the C ₁ -C ₂ fraction is usually consumed as private fuel. Also, propane in the C ₃ - _{C 4} fraction,
Although butane has wide applications as a household fuel, olefin gases such as propylene and butene have poor storage stability and a pungent odor, so they are rather undesirable as household fuels. One of the methods for effectively utilizing the olefin gas having 2 to 5 carbon atoms in the cracked gas is a polymerization gasoline method.
This method converts the olefin gas into gasoline by underpolymerizing it, and the reaction is OTG.
Also called reaction (abbreviation for olefin-to-gasoline). A solid acid is usually used as a catalyst, and it is well known that phosphoric acid is adsorbed and immobilized on diatomaceous earth or quartz sand, but in this case, the phosphoric acid washes away quickly, so the work of adsorbing and immobilizing the phosphoric acid is required frequently. There is a need to do. It is also known to use zeolite as a catalyst. In particular, ZSM-5, ZSM-11, where the zeolite pores consist of a 10-membered oxygen ring or a 12-membered ring,
Mordenite, Y-type, and dealkalized types of faujasite exhibit excellent OTG reaction activity. For example, JP-A-56-103292 discloses that high octane gasoline can be obtained in high yield by using a high Cv ratio zeolite such as ZSM-5 or ZSM-11 as a catalyst. However, these zeolite catalysts
In the OTG reaction, catalyst activity rapidly decreases due to coke accumulation, and it is necessary to frequently regenerate the catalyst by air calcination. <Purpose of the Invention> The present invention was made to solve these conventional drawbacks. It has low coke accumulation, high gasoline yield due to a long-life catalyst, and converts gasoline with a high octane number into carbon atoms with 2 to 5 carbon atoms. The purpose is to obtain olefin gas from a raw material gas containing olefin gas as an essential component. <Summary of the Invention> That is, the present invention provides a catalyst comprising dealkalized zeolite and aluminum fluoride, and a raw material comprising an olefin gas having 2 to 5 carbon atoms, or a mixture thereof with a paraffin gas having 1 to 5 carbon atoms. The present invention relates to a method for producing high octane gasoline, which is characterized by bringing gas into contact with heat. Examples of zeolite used as a base material for the OTG reaction catalyst of the present invention include phasiasite, gmelinite, zeolite L, mordenite, zeolite Ω, zeolite are mentioned, especially ZSM-5, ZSM
-11, mordenite, zeolite Y, and faujasite are preferably used. As is already widely known, the OTG reaction is an acid-catalyzed reaction. Therefore, in order to use the above-mentioned zeolite as a catalyst in the method of the present invention, it is necessary to dealkalize it with an acid or an ammonium salt to reduce the proportion of alkali in the zeolite. The dealkalization rate is 50 mol% of the alkali metal or alkaline earth metal contained in the zeolite.
More than 90 mol% is preferable, and 90 mol% or more is especially suitable. In this case, dealkalizing agents include mineral acids such as hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, and formic acid, acetic acid,
Examples include water-soluble organic acids such as malic acid and salts containing ammonium ions such as ammonium chloride and ammonium nitrate, and these acids or salts may be used alone or in combination. Among these, hydrochloric acid, nitric acid, ammonium chloride, ammonium nitrate, etc. are particularly preferred. These acids or salts are used in the form of an aqueous solution.
The acid concentration in that case varies depending on the processing conditions, but
The concentration is preferably 1 to 6N, and when an ammonium salt is used, the concentration is preferably 1 to 30%, particularly 5 to 15%. Although the treatment temperature may be room temperature, heating to 80 to 100°C is preferable to shorten the treatment time. Since the treatment time depends on the temperature, it cannot be stated unconditionally, but generally 5 hours to 3 days is preferable. The zeolite has a particle size of 0.01 to 1000μ, preferably
Aluminum fluoride used as a base material for the OTG reaction catalyst of the present invention, which is used in the form of powder or granules with a size of 0.1 to 100μ, is described, for example, by E. Baud Ann.
Chim. Phys., (8) 1, 60 (1904), A
Mazzuchelli.Atti Accad Lincei, (5)16i, 775
(1907) and WFFhrot, FTFroro, J.Am.Chem.
Soc., 67 , 64 (1945), etc. Aluminum trifluoride hydrate or JMCowley, TR
Scott, J.Am.Chem.Soc, 70 , 105 (1948); R.L.
Basic aluminum fluoride prepared by the method of Johnson, B. Siegel Nature 210 , 1256 (1966) is preferred. In particular, α-AlF ₃ ·3H ₂ O, β-AlF ₃ ·3H ₂ O and these are heated at a temperature of 700°C or lower, preferably 200 to 500°C.
Aluminum fluoride obtained by firing at ℃ is preferably used. Additionally, aluminum fluoride, which is equally effective, can be prepared by adding 200% of aluminum fluoride to a reactor filled with alumina, aluminum hydroxide, and mixtures thereof.
It can be obtained by passing an excess of anhydrous hydrogen fluoride at ~500°C and also by passing an excess of anhydrous hydrogen fluoride at 20-400°C into a reaction tube filled with aluminum chloride. When these aluminum fluorides are prepared as a component of the catalyst in the method of the present invention, it is not necessary to use them in pure form, and a mixture thereof is sufficient. The OTG catalyst used in the present invention is prepared in the form of powder or granules (1 to 5 mmφ) after mixing dealkalized zeolite and aluminum fluoride, which are thoroughly washed with water after acid treatment and dried at 50 to 200°C for 0.5 to 8 hours. Molded into an appropriate shape, for example, by compression molding, and
It can be obtained by firing at 700°C, preferably 300 to 600°C. Firing is normally carried out in air, but it is of course possible to carry out in 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 usually dealskalized zeolite is 20 to 99 wt%, preferably 40 to 90 wt%, and aluminum fluoride is 1 to 80 wt%, preferably 10
~60wt%. The catalyst used in the present invention must have two essential components as described above, and as shown in the examples below, even if any one component is missing,
OTG reaction cannot be carried out effectively. The raw material gas used in the OTG reaction of the present invention is composed of one or more olefin gases having 2 to 5 carbon atoms, or a mixture of one or more paraffin gases having 1 to 5 carbon atoms. In the case of a mixture, the total content of one or more olefin gases having 2 to 5 carbon atoms is preferably 5% or more, preferably 10% or more. The OTG reaction of the present invention is carried out in the gas phase using a raw material gas alone or in various gas atmospheres. Examples of the atmospheric gas include nitrogen, steam, hydrogen, and carbon dioxide. In the present invention, the OTG reaction is preferably accomplished under a hydrogen gas atmosphere. Hydrogen mainly has the effect of reducing the amount of carbonaceous precipitation. In the present invention, there is no particular restriction on the amount of hydrogen added to the raw material gas, but a molar ratio of raw material gas:hydrogen of 1:50 or less is sufficient, particularly 1:1 to 1:
A range of 5 is preferred. Since the catalyst of the present invention has extremely high activity for converting raw material gas into gasoline, the reaction proceeds even under normal pressure, but industrially it is preferable to operate under increased pressure, and the reaction pressure is below 100 atm, especially around 20 atm. is appropriate. The reaction temperature is preferably 250 to 500℃, especially
300-450℃ is good. Raw material gas supply rate per unit weight of catalyst, WHSV (g-raw material gas/g-cat・
hr) is not particularly limited, but in order to obtain a high conversion rate, it is preferably 10 or less, particularly preferably in the range of 0.5 to 2.0. In the present invention, the OTG reaction can be carried out by conventionally known fixed bed, fluidized bed or other methods, but a fixed bed gas phase reaction is most suitable in view of ease of operation. <Effects of the Invention> The catalyst used in the present invention has little coke accumulation and long life, and by using such a catalyst, it is possible to obtain high gasoline yield and high octane number. <Examples of the Invention> The method of the present invention will be specifically explained in detail below with reference to Examples. Example 1 After baking the Na type of ZSM-5 at 500℃ for 5 hours,
Acid treatment was carried out using normal hydrochloric acid at a temperature of 90 to 100°C for 5 hours. After thorough washing with water, the product was dried at 120°C for 5 hours to obtain a dealkalized ZSM-5 (catalyst A). 20wt for catalyst A treated with the above acid.
% of aluminum trifluoride is added and mixed to form a 3 x 4 mm
The pellets were compression molded into φ pellets and calcined at 500°C for 8 hours (Catalyst B). Using 2.0 g of the catalyst obtained in this way,
A life test of the OTG reaction was conducted at a temperature of 300°C, a hydrogen flow rate of 4.2/hr, a raw material gas flow rate of 2.0 g/hr, therefore a molar ratio of hydrogen and raw material gas = 3.0, and a WHSV = 1 hr ^-1 under normal pressure. . The results are shown in Table 1.

【table】

[Table] The C ₃ ′ + C ₄ ′ conversion rate and the generated hydrocarbon distribution immediately after oil passage (after 7 hours) are compared between catalysts A and B. The C ₃ ′+C ₄ ′ conversion rate was 95% for catalyst A, while it was low at 77% for catalyst B, and the initial activity of catalyst A was overwhelmingly higher. However, the C ₅ ⁺ gasoline yields for both catalysts A and B are approximately
Therefore, catalyst B has better selectivity to gasoline. Next, the activity and selectivity of both catalysts will be compared after about 2000 hours. The activity of catalyst A gradually decreases, and the C ₃ '+C ₄ ' conversion rate drops to 72% after 215 hours.
On the other hand, the activity of catalyst B hardly changed, and the conversion rate of C ₃ '+C ₄ ' after 220 hours was 74.3%. The yield of C ₅ ⁺ gasoline also decreased to about 20% for catalyst A, whereas catalyst B maintained a high value of 25%. From the above, it can be seen that Catalyst B is a catalyst with a long life and excellent selectivity to C ₅ ⁺ gasoline in the OTG reaction. Example 2 After calcining a Na type of synthetic mordenite at 500°C for 5 hours, acid treatment was performed using 2N hydrochloric acid at a temperature of 90 to 100°C for 5 hours. After thorough washing with water, heat at 120°C.
By drying for 5 hours, a dealkalized mordenite was obtained (catalyst C). 20wt for catalyst C treated with the above acid
% of aluminum trifluoride was added and mixed 3××4
It was molded into mmφ pellets and calcined at 500°C for 8 hours (Catalyst D). Using 2.0 g of the catalyst obtained in this way,
A lifetime test of the OTG reaction was conducted under the same reaction conditions as in Example 1. The results are shown in Table 2.

[Table] Catalyst D composite treated with aluminum trifluoride
It can be seen that compared to untreated product C, it has superior selectivity to C ₅ ⁺ gasoline and a longer life. Example 3 After calcining Na-type Y-type zeolite at 500°C for 5 hours, acid treatment was performed using 2N hydrochloric acid at a temperature of 90 to 100°C for 5 hours. After thorough washing with water, heat at 120°C.
By drying for 5 hours, a dealkalized Y-type zeolite was obtained (catalyst E). 20wt for catalyst E which was subjected to the above acid treatment
% of aluminum trifluoride is added and mixed to form a 3x4mm
It was molded into φ pellets and calcined at 500°C for 8 hours (Catalyst F). Using 2.0 g of the catalyst obtained in this way,
A lifetime test of the OTG reaction was conducted under the same reaction conditions as in Example 1. The results are shown in Table 3.

[Table] Catalyst F composited with aluminum trifluoride
It can be seen that compared to untreated product E, it has superior selectivity to C ₅ ⁺ gasoline and a longer life.

Claims (1)

[Claims] 1. A raw material gas consisting of an olefin gas having 2 to 5 carbon atoms, or a mixture of it and a paraffin gas having 1 to 5 carbon atoms, is heated over a catalyst consisting of dealkalized zeolite and aluminum fluoride. A method for producing high octane gasoline, which is characterized by contacting the gasoline. 2. The method for producing high octane gasoline according to claim 1, wherein the zeolite is ZSM-5, ZSM-11, mordenite, Y type, or faujasite. 3. The method for producing high octane gasoline according to claim 1, wherein the reaction is carried out in the presence of hydrogen.