JPH08157399A - Production of aromatic hydrocarbon - Google Patents

Abstract

PURPOSE: To provide a method for producing an aromatic hydrocarbon in high yield, capable of stably operating a reactor for a long period of time with minimized reduction in activity of a catalyst. CONSTITUTION: A light hydrocarbon raw material containing an olefin and/or a paraffin is supplied to a fixed bed heat insulating type reactor and a catalytic ring formation reaction is carried out under conditions wherein (1) a zeolite- based catalyst has an initial catalytic activity of >=0.2 (sec<-1> ) n-hexane decomposition activity, (2) the temperature of a catalyst bed is 450-650 deg.C, (3) the temperature distribution in the catalyst bed has at least one local maximum value and (4) the outlet temperature of the catalyst bed is in a range of the inlet temperature ±40 deg.C to provide the objective method for producing an aromatic hydrocarbon.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing aromatic hydrocarbons from light hydrocarbons. More specifically, the present invention provides that a light hydrocarbon feedstock is fed to a fixed bed adiabatic reactor having a fixed catalyst bed containing a specific zeolite-based catalyst, and the catalytic cyclization reaction is carried out under specific temperature conditions with respect to the catalyst bed. And a method for producing aromatic hydrocarbons from light hydrocarbons.

[0002]

2. Description of the Related Art Conventionally, a method for producing an aromatic hydrocarbon by using a zeolite such as ZSM-5 as a catalyst has been known. For example, Japanese Examined Patent Publication No. 56-42639 discloses a zeolite of ZSM-5 class, which is composed of paraffin, olefin and / or naphthene, and has a carbon number of 5 or more and an aromatic hydrocarbon content of 15% by weight or less. A method for producing an aromatic hydrocarbon by using as a catalyst is disclosed. Japanese Examined Patent Publication No. 4-5712 discloses a saturated hydrocarbon containing C ₄ or less and C.
₂ -C ₄ and from the raw material mixed in a specific ratio unsaturated hydrocarbon and virgin naphtha to ZSM-5 type zeolite discloses a process for producing an aromatic hydrocarbon as a catalyst.

US Pat. No. 3,845,150 uses a raw material containing 20 to 65% by weight of saturated hydrocarbon and 20 to 50% by weight of unsaturated hydrocarbon by using a ZSM-5 type zeolite catalyst. Discloses a method of converting an unsaturated hydrocarbon that undergoes an exothermic reaction and a saturated hydrocarbon that undergoes an endothermic reaction into aromatic hydrocarbons in an isothermal reaction in a heat balance state.

Japanese Patent Publication No. 3-503656 discloses a feedstock containing a lower alkane and a lower alkene.
Contacting with a fluidized bed of a catalyst containing acid type medium pore zeolite in the conversion zone to produce a reaction mixture (effluent stream) containing aromatic-rich higher aliphatic hydrocarbons, the reaction mixture in the second zone Discloses a method of producing a product containing alkylated aromatic-rich gasoline having 5 or more carbon atoms by contacting with a fluidized bed of a catalyst containing acid type medium pore zeolite.

Further, in Japanese Patent Laid-Open No. 63-69888, a crystalline zeolite having a specific activity is used to obtain C _2-
A process for converting a feed containing at least 50% by weight of C ₁₂ aliphatic hydrocarbons into aromatic compounds is disclosed. Japanese Unexamined Patent Publication No. 63-14732 discloses a method for producing aromatic hydrocarbons from light hydrocarbons using ZSM-5 type zeolite having a specific property containing zinc as a catalyst. Further, JP-A-3-182592 discloses that a hydrocarbon raw material containing an olefin is hydrogenated with a hydrogenation catalyst using hydrogen, and then a dehydrogenation cyclic dimerization reaction is carried out in a reactor containing a dehydrogenation cyclic dimerization catalyst. A method for obtaining aromatic hydrocarbons is disclosed.

[0006]

However, in the above-mentioned prior art, the production of aromatic hydrocarbons is attempted by using a fixed bed adiabatic reactor which has a simple structure, is efficient, and is industrially most desirable. In this case, the yield of the target aromatic hydrocarbon is low, or the coking is severe and stable operation becomes difficult.Therefore, the fixed bed adiabatic reactor provides a stable and high yield of the target aromatic hydrocarbon. It has been considered difficult to produce hydrocarbons. Therefore, for example, as in the method described in JP-A-3-182592, it is necessary to hydrogenate the olefin in the raw material in advance and then perform a two-step reaction for producing an aromatic hydrocarbon by a dehydrogenative cyclic dimerization reaction. There was a problem that was. Alternatively, conventionally, there has been a problem that a complicated reaction apparatus such as an isothermal reactor, a moving bed reactor, a fluidized bed reactor is required.

In US Pat. No. 3,845,150, the reaction system is heat-balanced by using a raw material having a specific saturated hydrocarbon / unsaturated hydrocarbon weight ratio, and there is almost no external heat supply. Although a method for obtaining an aromatic yield equivalent to that when a large amount of heat is supplied is disclosed,
No reference is made to the temperature distribution in the system, and there is no description about a method of reducing the activity deterioration of the catalyst due to coking and operating stably.

Further, in Japanese Patent Publication No. H03-503656, alkylated aromatic compounds are prepared by using a raw material containing a lower alkane and a lower alkene in a quantitative ratio that can be maintained near an isothermal reaction condition in a conversion zone. Disclosed is a method for producing a product containing an enriched gasoline having 5 or more carbon atoms. In this case, catalyst activity deterioration due to coking is caused by fluidized bed reactor (catalyst reaction and catalyst regeneration). Both can be done continuously) to avoid. However, the fluidized bed reactor used in this method has a complicated structure and is expensive.

[0009]

The inventor of the present invention has conducted extensive studies to overcome the above problems of the prior art. as a result,
Surprisingly, by feeding a light hydrocarbon feedstock containing at least one selected from olefins and paraffins to a fixed bed adiabatic reactor having a fixed catalyst bed containing the zeolite catalyst, the zeolite catalyst is produced in the reactor. When producing an aromatic hydrocarbon from a light hydrocarbon raw material by carrying out a catalytic cyclization reaction of a light hydrocarbon raw material by bringing it into contact with, a zeolite-based catalyst having a specific activity is used, and a specific temperature condition for a catalyst bed is used. If you do below,
It has been found that the target aromatic hydrocarbon can be obtained in a high yield, the activity of the catalyst is not significantly reduced, and the production can be stably performed for a long period of time. The present invention has been completed based on the above findings.

Therefore, one of the main objects of the present invention is to use a zeolite-based catalyst, a fixed bed adiabatic reactor, and a high yield from a light hydrocarbon feedstock containing at least one selected from olefins and paraffins. Another object of the present invention is to provide a method for stably producing aromatic hydrocarbons for a long period of time.

The above and other objects, features and benefits of the present invention will be described in detail below. Basically, according to the present invention, in a method for producing an aromatic hydrocarbon from a light hydrocarbon by catalytic cyclization, a light hydrocarbon raw material containing at least one selected from an olefin and a paraffin is substantially fresh. By supplying to a fixed bed adiabatic reactor having a fixed catalyst bed containing at least one zeolite catalyst selected from the group consisting of zeolite catalyst and steam-treated zeolite catalyst, contact with the zeolite catalyst in the reactor In carrying out the catalytic cyclization reaction of the light hydrocarbon raw material, the catalytic cyclization reaction is carried out under conditions satisfying the following requirements (1), (2), (3) and (4). A method for producing an aromatic hydrocarbon is provided.

(1) As the value of the first-order reaction rate constant of the initial stage of the decomposition of n-hexane by the zeolite-based catalyst measured at 500 ° C. and atmospheric pressure, 0.2 (s)
ec ^-1 ) or higher initial catalytic activity. (2) The temperature of the catalyst bed is 450 to 650 ° C. (3) The catalyst bed has a temperature distribution with respect to the distance from the inlet to the outlet of the catalyst bed, and the temperature distribution has at least one maximum value. (4) The temperature at the outlet of the catalyst bed is within a range of ± 40 ° C with respect to the temperature at the inlet of the catalyst bed.

The "substantially fresh zeolite-based catalyst" in the present invention includes not only steam-untreated zeolite-based catalysts but also steam-treated catalysts to the extent that substantial reforming is not achieved. In addition, "substantial reforming" means that the dealumination degree normally intended is achieved in steam treatment.

Next, in order to facilitate understanding of the present invention,
First, the basic configuration and preferable aspects of the present invention will be listed. 1. In a method for producing an aromatic hydrocarbon from a light hydrocarbon by catalytic cyclization, a light hydrocarbon raw material containing at least one selected from olefin and paraffin,
By supplying to a fixed-bed adiabatic reactor having a fixed catalyst bed containing a zeolite-based catalyst that is at least one selected from the group consisting of substantially fresh zeolite-based catalyst and steam-treated zeolite-based catalyst, When carrying out a catalytic cyclization reaction of a light hydrocarbon raw material by bringing it into contact with a zeolite-based catalyst, the catalytic cyclization reaction is carried out under the condition that the following requirements (1), (2), (3) and (4) are satisfied. A method for producing an aromatic hydrocarbon, characterized by carrying out the method.

(1) As the value of the initial first-order reaction rate constant of the decomposition of n-hexane by the zeolite-based catalyst measured at 500 ° C. and atmospheric pressure, 0.2 (s)
ec ^-1 ) or higher initial catalytic activity. (2) The temperature of the catalyst bed is 450 to 650 ° C. (3) The catalyst bed has a temperature distribution with respect to the distance from the inlet to the outlet of the catalyst bed, and the temperature distribution has at least one maximum value. (4) The temperature at the outlet of the catalyst bed is within a range of ± 40 ° C with respect to the temperature at the inlet of the catalyst bed.

2. 2. The method according to item 1 above, wherein the zeolite-based catalyst consists essentially of zeolite. 3. Zeolite-based catalyst is zeolite and VIII
The method according to item 1 above, which comprises a mixture with at least one metal selected from the group Ib group, the group IIb group, the group IIb group and the group IIIb group and compounds thereof. 4. 4. The method according to item 3 above, wherein the zeolite-based catalyst comprises a mixture of zeolite and at least one selected from zinc and its compounds. 5. 5. The method according to item 4 above, wherein the zeolite-based catalyst comprises a mixture of zeolite, at least one selected from zinc and its compounds, and alumina.

6. Zeolite-based catalyst and zeolite,
5. The method according to item 4 above, which comprises a mixture of at least one selected from zinc and its compounds, and a mixture of alumina and heat treated in steam. 7. 5. The method according to item 4, wherein the zeolite-based catalyst comprises a mixture of zeolite and zinc aluminate. 8. The content of at least one selected from zinc and its compounds in the zeolite-based catalyst is 5 to 25 as zinc.
The method according to any one of items 4 to 7 above, which is% by weight.

9. 2. The method according to item 1, wherein the zeolite of the zeolite-based catalyst is replaced with a metal belonging to Group VIII, Group Ib, Group IIb and Group IIIb of the periodic table. 10. The zeolite of the zeolite-based catalyst has a zeolite skeleton having an Si / Al atomic ratio of 12 or more, and
Containing Na at a concentration of 500 ppm by weight or less
10. The method according to any one of claims 9 to 9. 11. 11. The method according to any one of items 1 to 10 above, wherein the zeolite-based catalyst comprises ZSM-5 type zeolite.

12. The zeolite-based catalyst is a substantially fresh zeolite-based catalyst.
1. The method according to any one of 1. 13. 12. The method according to any one of items 1 to 11 above, wherein the zeolite-based catalyst is a steam-treated catalyst obtained by steam-treating a substantially fresh zeolite-based catalyst. 14. The zeolite-based catalyst is a steam-treated catalyst obtained by steam-treating a substantially fresh zeolite-based catalyst consisting essentially of zeolite, and Group VIII, Ib, and II of the periodic table.
2. The method according to item 1 above, which comprises a mixture with at least one selected from the group b and group IIIb metals and their compounds.

15. Steam treatment of a substantially fresh zeolite-based catalyst is performed by passing steam through a steam treatment reactor containing the substantially fresh zeolite-based catalyst in the following steps (a) and (b). 15. The method according to item 13 or 14 above, which is performed. (A) Water vapor partial pressure 0.1 kg / cm ² or more, temperature 500 to 6
Steam at 50 ° C. is circulated in the steam treatment reactor to be contacted with a substantially fresh zeolite-based catalyst for 0.1 to 3 hours, and then (b) the flow of steam is temporarily stopped,
After removing the residual steam in the steam treatment reactor, the steam partial pressure is further 0.1 to 10 kg / cm ² , and the temperature is 515 to 700 ° C.
Water vapor of which the temperature is higher than the flowing water vapor temperature in the above step (a) is passed through the reactor, the step (b) is performed at least once, and in each step (b), it is flowed there. The steam generated is brought into contact with the zeolite-based catalyst steam-treated in the step before the step (b).

16. The light hydrocarbon raw material is a C ₄ fraction of a product obtained from a high-temperature pyrolysis apparatus for petroleum hydrocarbon materials, or butadiene or butadiene and i from the C ₄ fraction.
- fraction excluding butene; pyrolysis gasoline;; C ₅ fraction of the product obtained from the high temperature thermal cracking unit of a petroleum hydrocarbon material, or fraction excluding dienes from the C ₅ fraction pyrolysis gasoline A raffinate further extracted with an aromatic hydrocarbon; an FCC-LPG; an FCC cracked gasoline; a raffinate extracted with an aromatic hydrocarbon from a reformate; a LPG from Coker; and at least one selected from straight-run naphtha. The method according to any one of items 1 to 15 above.

17. The light hydrocarbon raw material is composed of saturated hydrocarbon and unsaturated hydrocarbon, and the weight ratio of saturated hydrocarbon to unsaturated hydrocarbon in the light hydrocarbon raw material is 0.43 to
It is 2.33, The method in any one of the preceding clauses 1-16 characterized by the above-mentioned. 18. The pressure in the fixed bed adiabatic reactor during the cyclization reaction is atmospheric pressure to 30 kg / cm ² · G, and the light hydrocarbon raw material has a weight hourly space velocity (WHSV) of 0.1 to 50 hr ^{−. 1}
The method according to any one of items 1 to 17 above, wherein

19. The produced cyclization reaction mixture containing aromatic hydrocarbons was subjected to a gas-liquid separation tank and, optionally, a distillation column to produce a product A rich in aromatic hydrocarbons, hydrogen and carbon atoms of 1 to 5 19. The method according to any one of items 1 to 18 above, wherein the product B is mainly composed of the non-aromatic hydrocarbon. 20. The produced cyclization reaction mixture containing aromatic hydrocarbons was subjected to a gas-liquid separation tank and, optionally, a distillation column to obtain a product A rich in aromatic hydrocarbons and a non-carbonated product containing 4 or 5 carbon atoms. Product C containing mainly aromatic hydrocarbons and product D containing mainly hydrogen and non-aromatic hydrocarbons having 1 to 3 carbon atoms
The method according to any one of the above items 1 to 18, characterized in that

21. As a refrigerant used for gas-liquid separation in the gas-liquid separation tank, a refrigerant system made of propylene or ethylene produced in an ethylene production process including high temperature pyrolysis of petroleum hydrocarbons and used as a refrigerant in the process. 21. The method according to item 19 or 20 above, wherein 22. At least a part of the product B mainly composed of hydrogen and a non-aromatic hydrocarbon having 1 to 5 carbon atoms is recycled to a fixed bed adiabatic reactor and used as a part of a light hydrocarbon raw material. The method according to item 19 above. 23. At least a part of a product B mainly composed of hydrogen and a non-aromatic hydrocarbon having 1 to 5 carbon atoms is supplied to a high-temperature thermal decomposition apparatus for petroleum hydrocarbon material.
9. The method according to 9.

24. At least a part of at least one selected from a product C mainly composed of a non-aromatic hydrocarbon having 4 and 5 carbon atoms and hydrogen and a product D mainly composed of a non-aromatic hydrocarbon having 1 to 3 carbon atoms, 21. The method according to item 20, which is recycled to a fixed bed adiabatic reactor and used as a part of a light hydrocarbon raw material. 25. At least a part of at least one selected from a product C mainly composed of a non-aromatic hydrocarbon having 4 and 5 carbon atoms and hydrogen and a product D mainly composed of a non-aromatic hydrocarbon having 1 to 3 carbon atoms, 21. The method according to item 20, wherein the petroleum hydrocarbon material is supplied to a high temperature pyrolysis apparatus.

26. Aromatic hydrocarbon-rich product A
Is further treated by at least one method selected from the following methods. A method of introducing the product A into a dealkylation reactor to obtain benzene; a method of introducing the product A into a distillation apparatus or an extraction apparatus or an extractive distillation apparatus to obtain benzene, toluene, and xylene; A method of treating with an isomerization reactor or an isomerization reactor; and a method of blending the product A with gasoline.

27. The supply of the light hydrocarbon raw material to the fixed bed adiabatic reactor is temporarily stopped, and the coke accumulated on the zeolite-based catalyst during the cyclization reaction is burned and removed in the catalyst regeneration zone by using an oxygen-containing inert gas. The method according to any one of items 1 to 26 above, further comprising regenerating the zeolite-based catalyst by:

28. The exhaust combustion gas from the catalyst regeneration zone is recycled through the heating furnace to the catalyst regeneration zone using a circulation compressor, and the catalyst regeneration zone, the circulation compressor and the heating furnace are connected in this order by piping. Forming a gas circulation system for combustion and supplying fresh oxygen-containing inert gas,
The first inlet located between the catalyst regeneration zone outlet of the combustion gas circulation system and the heating furnace inlet is supplied with an amount of 0.05 to 50% by volume with respect to the circulation amount of the combustion gas, Discharging exhaust combustion gas from the catalyst regeneration zone to the outside of the system by an amount substantially equal to the amount of the fresh oxygen-containing inert gas supplied to the first inlet before reaching the heating furnace;
At that time, the supply amount and the oxygen content of the fresh oxygen-containing inert gas are adjusted so that the oxygen content of the combustion gas introduced into the catalyst regeneration zone is 0.01 to 10% by volume. The method according to item 27 above.

29. Further, a fresh inert gas containing no oxygen is provided at the same inlet as the above-mentioned first inlet or between the outlet of the catalyst regeneration zone of the combustion gas circulation system and the inlet of the heating furnace separately from the first inlet. To the second inlet, which is an inlet for supplying the combustion gas discharged from the catalyst regeneration zone to the heating furnace, while supplying an amount of 10% by volume or less with respect to the circulation amount of the combustion gas. , By additionally discharging out of the system by an amount substantially equal to the amount of fresh oxygen-free inert gas supplied to the second inlet,
29. The method according to item 28 above, which comprises suppressing an increase in the partial pressure of water vapor of the combustion gas flowing into the catalyst regeneration zone.

30. Further comprising cooling the combustion gas to be compressed by the circulating compressor and heating the compressed combustion gas before reaching the furnace, wherein
The method according to item 29 above, wherein cooling and heating are performed by at least one heat exchanger. 31. Performing steam treatment of the above-mentioned substantially fresh zeolite-based catalyst using a steam circulation system including a steam treatment reactor, a circulation compressor, a heating furnace and at least one heat exchanger connected by piping. The preceding paragraph 1 characterized by
The method according to any one of 3 to 15.

32. 32. The method according to item 31 above, wherein the steam treatment reactor is used as the adiabatic reactor. 33. The steam circulation system is used as a combustion gas circulation system for regenerating the zeolite-based catalyst according to the method of the preceding paragraph 30, wherein the steam treatment reactor includes a catalyst regeneration zone in the combustion gas circulation system. The catalyst regeneration reactor as it is, or the combustion gas used in the combustion gas circulation system is used instead of the catalyst regeneration reactor and in place of the steam used in the steam circulation system. Or the method described in 32.

The zeolite of the zeolite-based catalyst used in the method of the present invention has a Si / Al atomic ratio of the zeolite skeleton of 2 to 60. For example, β-zeolite, Ω-zeolite, Y-zeolite, L-zeolite, Erionite, offretite, mordenite, ferrierite, Z
SM-5, ZSM-8, ZSM-11, ZSM-12,
ZSM-35, ZSM-38, etc. are mentioned, but ZSM
ZSM-5 type crystalline aluminosilicates or metallosilicates such as -5, ZSM-8 and ZSM-11 are preferred. For the ZSM-5 type zeolite, for example, reference can be made to US Pat. No. 5,268,162.

As the zeolite-based catalyst used in the present invention, a catalyst consisting essentially of zeolite can be used, and the above-mentioned zeolite, VIII group, Ib group, IIb
A mixture with at least one metal selected from Group III or Group IIIb metals and at least one selected from the group consisting of those compounds (for example, metal oxides that promote dehydrogenation such as zinc oxide). Those are preferable. VI
Zn, Cu, Ag, Ni, Pt, Pd, and Ga are more preferable as the metal belonging to the II, Ib, IIb, and IIIb groups, and among these, Zn, Ag, Ni, and Ga are more preferably used. To be For example, it is preferable to contain a mixture of zeolite and at least one selected from zinc and its compounds. Further, it is more preferable to use alumina and silica together as a binder.

In the method of the present invention, at least one selected from the following zinc and its compounds (hereinafter often referred to as "zinc component") is, for example, zinc, zinc oxide, zinc hydroxide, zinc nitrate, carbonic acid. Examples thereof include salts such as zinc, zinc sulfate, zinc chloride, zinc acetate and zinc oxalate, and organic zinc compounds such as alkyl zinc.

In the method of the present invention, the zeolite-based catalyst preferably contains a mixture of zeolite, a zinc component, and alumina. Further, a mixture of zeolite obtained by heat-treating a mixture of a zinc component and alumina in steam is also preferable. When steam treatment is performed for both catalysts as described in detail below, the zinc component reacts with alumina and changes to zinc aluminate, which stabilizes the zinc and significantly reduces the zinc scattering loss under the cyclization reaction conditions. It can be reduced. Similar effects can be obtained even when the zeolite-based catalyst is a mixture of zeolite and zinc aluminate. Zinc aluminate as used herein means JCPDS 5-0669 NBS Circ., 5 when observed with an X-ray diffractometer such as XD-610 manufactured by Shimadzu Corporation.
39, Vol. II, 38 (1953), having the same X-ray diffraction pattern.

In the method of the present invention, as alumina, anhydrous alumina or a hydrate of alumina can be used. In addition, anhydrous alumina or alumina hydrate can be obtained by hydrolysis or thermal decomposition such as an aluminum salt, or oxidation. It is also possible to use a raw material that produces a product.

In the above zeolite-based catalyst, the content of at least one selected from zinc and its compounds is preferably 5 to 25% by weight as zinc.
When alumina is contained, the alumina content is 5 to 50% by weight, preferably 20 to ₄ as Al ₂ O _{3 based} on the total catalyst.
When it is 0% by weight and contains alumina and zinc,
The molar ratio of alumina to zinc (Al ₂ O ₃ / Zn) is 1 or more.

The zeolites used in the present invention are all H 2
It can be used as a type or a metal substitution type, and the metal of the metal substitution type is preferably a metal belonging to Group VIII, Ib, IIb, or IIIb. Group VIII, Ib,
Metals belonging to the IIb group and the IIIb group include Zn, Cu,
Ag, Ni, Pt, Pd, and Ga are more preferable, and Zn, Ag, Ni, and Ga are more preferably used. Further, as described above, it can be used in combination with a binder such as alumina and / or a metal oxide such as zinc oxide which promotes dehydrogenation.

It is known that the activity changes depending on the concentration of Na remaining in the zeolite, and the Na concentration in the zeolite-based catalyst is preferably low, and particularly preferably 500 ppm by weight or less. This is particularly important when using a zeolite having a Si / Al atomic ratio of the zeolite skeleton of 12 or more.

Si / Al having the zeolite skeleton referred to in the present invention
The atomic ratio refers to the Si / Al atomic ratio obtained from ²⁹ Si-NMR. Si / Z in zeolite using ²⁹ Si-NMR
For the method of obtaining the Al atomic ratio, see “Experimental Chemistry Course 5,
NMR ", 4th edition (Japan Maruzen Co., Ltd., 1992) 2
32 to 233.

The zeolite-based catalyst used in the method of the present invention is preferably a steam-treated zeolite-based catalyst obtained by steam-treating a substantially fresh zeolite-based catalyst. By the steam treatment, accumulation of coke-like substances on the zeolite-based catalyst during the catalyst cyclization reaction can be reduced, and deterioration of the activity of the catalyst over time can be reduced.

The above steam treatment can be carried out, for example, at a steam partial pressure of 0.1 to 10 kg / cm ² , a processing temperature of 500 to 800 ° C., and a processing time of 0.1 to 50 hours. Further, as described in JP-A-2-115134, when the steam treatment is carried out, zinc is stabilized in a zeolite-based catalyst composed of zeolite, a zinc component and alumina, and the evaporation loss of zinc under reaction conditions is significantly increased. Can be reduced to

As a method for obtaining a steam-treated zeolite-based catalyst comprising a mixture system of other components such as zeolite and zinc, for example, (1) first, the above-mentioned mixture system is provided, and the mixture system is steam-treated; 2) A steam-treated catalyst obtained by steam-treating a substantially fresh zeolite-based catalyst consisting essentially of zeolite, and Group VIII, I of the Periodic Table
at least one selected from the group b, the group IIb and the group IIIb and compounds thereof, and optionally a method of further mixing with other components such as alumina and silica, and (3) obtained by the method (2) above. The method of steam-treating the obtained mixture again can be mentioned.

Stabilization of zeolite by steam treatment is
It is known that the aluminum in zeolite is partially desorbed by steam treatment (hereinafter referred to as "dealuminization"), but it is stable and uniform on an industrial scale. In order to do so, the heat of reaction generated during the steam treatment is large, and the dealumination rate has a large temperature dependency, so control of the catalyst temperature during the steam treatment is very important. It is presumed that aluminum in zeolite is desorbed by the steam treatment through the following processes.

[0045]

Embedded image

(1) The dealumination reaction proceeds in two stages. (2) The first reaction is a reversible reaction, and water vapor (H ₂ O)
When the supply of is stopped, the intermediate in the above formula becomes aluminum in the zeolite skeleton. (3) The first reaction is much faster than the second reaction. The heat of reaction generated during the steam treatment is generated by the first reaction. (4) The second reaction is an irreversible reaction and is very slow. Since the reaction heat resulting from the first reaction is large and the reaction is very fast, when steam is excessively supplied to the catalyst bed, the temperature rises over the entire area of the catalyst bed immediately after the steam is supplied, and thereafter the temperature rises. Does not continue, but is cooled by circulating steam or inert gas.

FIG. 4 is a view showing an example of a preferable uniform temperature distribution in the catalyst bed when steam-treating the zeolite-based catalyst used in the method of the present invention, together with an unfavorable non-uniform temperature distribution. FIG. 4 is an example in which steam at a temperature T ₀ is supplied and circulated from the upper part of the reactor for 60 minutes using a fixed bed single-stage adiabatic reactor to perform steam treatment. In FIG. 4, the solid lines show the temperature distribution in the reactor at a certain time after the start of steam supply, and the dotted lines show the time-average temperature distribution at each position from immediately after the start of steam supply to 60 minutes later.

When the time-averaged temperature distribution has a distribution such as the dotted line, the activity of the catalyst near the reactor inlet, that is, the portion where the feed fluid first contacts the catalyst bed packed in the reactor, the activity of the catalyst at the reactor outlet is increased. The activity becomes higher than that of the catalyst in the vicinity, and the activity after the steam treatment is distributed. In other words, the value obtained by averaging the catalyst activity when the steam treatment is performed with the time average temperature distribution represented by the dotted line over all layers is the catalyst bed average temperature (T) represented by the one-dot chain line, and shows a uniform temperature. The distribution shows the same activity value as that of the catalyst when treated with steam, but when treated with the temperature distribution indicated by the dotted line in the former case, the activity has a distribution.

Therefore, in the catalytic cyclization reaction or the like using the catalyst after the steam treatment, there is a problem that the coking at the catalyst near the reactor inlet becomes severe and the deterioration due to the coking becomes large. Therefore, in order to obtain a catalyst having a sufficiently stable activity and a high reaction activity over the entire area of the catalyst bed, it is preferable to carry out the steam treatment at a substantially constant temperature such as the one-dot chain line.

When dealumination is carried out by a method in which the flow of water vapor is carried out in one step, the temperature of the catalyst bed differs between the upper part of the catalyst bed and the lower part of the catalyst bed as shown by the solid line in FIG.
It may be difficult to carry out uniform dealumination.
Therefore, in the steam treatment in the present invention, it is more preferable to carry out the steam distribution in two or more stages under the following conditions. That is, it is preferable to perform steam treatment by passing steam through the steam treatment reactor containing a substantially fresh zeolite catalyst in the following steps (a) and (b).

(A) Steam having a partial pressure of steam of 0.1 kg / cm ² or more and a temperature of 500 to 650 ° C. is passed through a steam treatment reactor to give a substantially fresh zeolite catalyst for 0.1 hours to
After contacting for 3 hours, (b) stopping the flow of water vapor and removing the residual water vapor in the water vapor treatment reactor, the water vapor partial pressure is further 0.1 to 10 kg / cm ² , and the temperature is 515 to 70.
A steam having a temperature of 0 ° C. and having a temperature higher than the circulating steam temperature in the step (a) is passed through the reactor, the step (b) is performed at least once, and in each step (b), The steam flowing in the step (a) is brought into contact with the zeolite-based catalyst steam-treated in the step before the step (b).

In the above preferred embodiment, the temperature difference between the upper layer portion and the lower layer portion of the catalyst bed can be reduced by distributing the steam in two or more stages as follows, so that a stable and uniform steam treatment is carried out. be able to. In the first step (a) of the two-step steam heat treatment in this preferred embodiment, the steam partial pressure is 0.1 kg / cm ² or more, preferably 0.5 to ¹ kg / cm ² , and the temperature is 500 to 650 ° C., preferably Is 550 to 650 ° C., more preferably 600 to 620
℃ water vapor to the fresh zeolite catalyst 0.1
The contact is performed for about 3 hours, preferably 0.1 to 1 hour.

The steam is supplied at a partial pressure of 0.1 kg / cm ² or more, but the steam may be diluted with an inert gas at that time.
In this case, the concentration of water vapor is preferably 10% by volume or more,
It is particularly preferably 20 to 80%. The inert gas is selected from those which generate H ₂ O upon contact with zeolite, for example, alcohols, ethers, etc., but nitrogen is particularly preferable. Weight hourly space velocity (WHSV) of water vapor
With regard to the above, it is preferable that the water vapor partial pressure does not change in the zeolite layer and there is no problem such as uneven flow, and it is particularly preferable to set WHSV to 0.01 to 10 hr ⁻¹ .

When the steam temperature is lower than 500 ° C., the reaction heat suppressing effect at the time of the second and subsequent treatments is small, and when steam is introduced at a temperature higher than 650 ° C., the reaction heat generated by the steam treatment causes the catalyst bed temperature to be extremely high. Since the temperature rises, there is a problem that it is necessary to use a material having excellent high temperature corrosion resistance. Further, when the steam treatment time of the first stage by the above method is long, a large temperature distribution is generated in the catalyst bed due to the generated heat of reaction, so that the degree of dealumination in the catalyst bed can be varied, and the catalyst after the steam treatment can be varied. Distribution of activity occurs.

In the step (b) of the second step in the steam heat treatment of the two steps, the supply / flow of steam is stopped following the step (a) of the first step, and the temperature is from 20 to 700 ° C., preferably from 20 to 700 ° C. Residual water vapor is removed by the inert gas at 600 ° C., preferably, the average temperature of the catalyst bed becomes equal to the second stage water vapor temperature, and the temperature difference between the maximum temperature and the minimum temperature of the temperature distribution of the catalyst bed is 10 ° C. Homogenize until: If the residual steam is not removed after the supply / circulation of the steam is stopped, dealumination proceeds due to the residual steam, which is not preferable for uniform dealumination.
Subsequently, the steam partial pressure is 0.1 to 10 kg / cm ² , preferably 0.5 to 1 kg / cm ² , the treatment temperature is 515 to 700 ° C., and preferably the maximum temperature of the catalyst bed increased during the first stage steam treatment ± Steam at a temperature of 10 ° C. is contacted for 0.1 to 50 hours, preferably 0.1 to 20 hours.

The treatment (b) may be carried out twice or more including the treatment step. The reaction heat generated in the second and subsequent treatments is about 1/4 to 3/5 of the reaction heat amount in the first step (a), so the temperature difference in the catalyst bed is also kept smaller than in the first step. This enables stable and uniform dealumination. In the present invention, a zeolite catalyst that has been partially dealuminated by the method described in South African Patent Application No. 94/7674 (corresponding to International Patent Application Publication No. WO95 / 09050) can be preferably used. .

In the method of the present invention, a fixed bed adiabatic reactor is used as the reactor. Regarding the adiabatic reactor, “Industrial Reactor” edited by Kenji Hashimoto (Baifukan, Japan, 1984).
Reference can be made to the reactor described on pages 25-26.
Examples of the adiabatic reactor include a fixed bed adiabatic reactor, a moving bed adiabatic reactor, and a fluidized bed adiabatic reactor.
A fixed bed adiabatic reactor is used in the process of the present invention. A fixed bed single-stage adiabatic reactor with only one fixed catalyst bed is more preferable, but an intermediate heat exchange / multi-stage heat insulation in which the catalyst bed is divided into several stages and a heat exchanger is provided between the stages to supply or remove heat. It may be a type reactor. Since carbonaceous matter (coke) accumulates on the catalyst as the reaction proceeds, a fixed-bed, single-stage adiabatic reactor with a two-column switching system that allows combustion and removal of the carbonaceous matter while continuing the reaction is preferable.

The light hydrocarbon raw material containing at least one selected from olefins and paraffins in the method of the present invention means a carbon number of 2 or more and a 90% distillation temperature of 190 ° C.
The following hydrocarbons. Examples of such paraffins include ethane, propane, butane, pentane, hexane, heptane, octane and nonane. Further, examples of such olefins include ethylene, propylene, butene, pentene, hexene, heptene, octene and nonene. In addition to the above, cycloparaffins such as cyclopentane, methylcyclopentane, and cyclohexane; cycloolefins such as cyclopentene, methylcyclopentene, and cyclohexene; and / or dienes such as cyclohexadiene, butadiene, pentadiene, and cyclopentadiene may be included. .

A mixture of the above hydrocarbons may be used as a raw material, and the mixture may contain N ₂ and CO as diluents.
_In order to suppress the production of inert gases such as ₂ , CO and carbonaceous matter (coke) accumulated on the catalyst during the reaction, H ₂ , C
It may contain H ₄ . These diluents may preferably be contained in 20% by volume or less, more preferably 10% by volume or less. Further, as the above mixture, it is particularly preferable to use a mixture containing saturated hydrocarbon and unsaturated hydrocarbon in a weight ratio of 0.43 to 2.33.

The weight ratio of the saturated hydrocarbon to the unsaturated hydrocarbon as used herein means the weight ratio in the mixture supplied,
For example, as shown in FIG. 9 which will be described in detail later, as shown in FIG.
When the outlet product of 0 is separated into the target aromatic hydrocarbons and the non-aromatic hydrocarbons as unreacted raw materials or by-products by the refining separation means 41, and the resulting non-aromatic hydrocarbons are recycled. Means the weight ratio in the mixture 44 after mixing the fresh feed 43 and the recycle component 42.

As the mixture, a mixture of the above hydrocarbons, a C ₄ fraction of a high temperature thermal decomposition product of a petroleum hydrocarbon such as naphtha, or butadiene or butadiene and i-butene are removed from the C ₄ fraction. Distillate; C ₅ fraction of high-temperature pyrolysis products of petroleum hydrocarbons, or fraction obtained by removing dienes from the C ₅ fraction; Pyrolysis gasoline; Aromatic hydrocarbon extraction from pyrolysis gasoline Raffinate; FCC
-LPG; FCC cracked gasoline; raffinate with aromatic hydrocarbons extracted from reformate; Coker LP
G: straight-distilled naphtha, of which C ₄ fraction of high temperature thermal decomposition products of petroleum hydrocarbons such as naphtha; C ₅ fraction; C ₄ fraction and C ₅ fraction from butadiene; A fraction obtained by removing a part or all of i-butene, isoprene, and cyclopentadiene can be particularly preferably used, and the C ₄ fraction, C
_A raw material in which the weight ratio of the ₅ fractions is 3/7 to 7/3 is particularly preferable.

The above mixture may be used alone or in combination of two or more kinds. The high-temperature pyrolysis product referred to here means that produced by a pyrolysis device used in a tubular pyrolysis method called steam cracking, and steam cracking is described in "The Oil and Gas". Journal magazine "P220-222, M
AY12,1969. In the method of the present invention, the raw material may contain oxygen-containing compounds such as TBA (tertiary-butyl alcohol) and methanol as impurities.

In the present invention, the initial first-order reaction rate constant of n-hexane decomposition by a zeolite-based catalyst (hereinafter, often referred to as "initial n-hexane decomposition first-order reaction rate constant") is shown in FIG. The n-hexane decomposition reaction is carried out using the apparatus and the zeolite-based catalyst, and it is determined as follows from the volume of the zeolite-based catalyst used, the raw material n-hexane flow rate, and the n-hexane concentration in the obtained reaction product.

That is, in FIG. 8, a quartz reaction tube 29 having a diameter of 10 mm is filled with quartz wool 36, a catalyst 35, and a Raschig ring 32 in this order from the bottom, and the catalyst 35 measured by a thermometer 30.
The quartz reaction tube 29 in the electric furnace 33 in which the temperature can be adjusted by the temperature adjusting thermocouple 34 so that the temperature becomes equal to 500 ° C.
Is heated to atmospheric pressure, weight hourly space velocity (WHSV) 4hr
-N-hexane was supplied to the catalyst 35 from the raw material inlet 31 through the Raschig ring 32 under the condition of ^-1 , and the reaction product of 0.75 hours to 1 hour after the n-hexane was supplied, that is, 0.25 hours. After cooling with condenser 37,
The oil trap 38 is further cooled with a dry ice / ethanol refrigerant, and all the oil components separated in the oil trap 38 and the gas components separated in the generated gas collecting bag 39 are collected.

FID-TCD gas chromatography (HP-manufactured by Hewlett-Packard Company, USA)
5890 series II), gas composition is FID gas chromatography (GC-1 manufactured by Shimadzu Corporation, Japan).
7A), the n-hexane concentration in the reaction product obtained by analyzing the oil composition was substituted into the following equation together with the volume of the zeolite catalyst used and the flow rate of the raw material n-hexane, and 0.75 after supplying n-hexane. The initial n-hexane decomposition first-order reaction rate constant of the average of gas and oil collection time of 0.25 hours from the time of 1 hour is obtained.

[0066]

[Equation 1]

In the above formula, "the volume of the zeolite catalyst" means only the zeolite catalyst which does not contain the volume of the inert substance (Raschig ring, or glass beads in some cases) contained in the catalyst bed in the above measurement test. Means the volume of. Thus, the volume of the zeolite-based catalyst alone is used as the “volume of the zeolite-based catalyst”, and the initial n-hexane decomposition first-order reaction rate constant based on the zeolite-based catalyst is obtained from the above equation. In the present invention, the initial n-hexane decomposition first-order reaction rate constant (hr ⁻¹ ) obtained by the above equation is (s)
Used in units of ec ^-1 ).

In the method of the present invention, as described above, it is necessary for the zeolite catalyst to satisfy the following requirement (1). (1) The zeolite-based catalyst has an initial first-order reaction rate constant of 0.2 (sec ⁻¹ ) or more as the value of the initial first-order reaction rate constant of n-hexane decomposition by the zeolite-based catalyst measured at 500 ° C. under atmospheric pressure. It has catalytic activity.

The zeolite-based catalyst had a value of 0.2 (sec ^-1 ) as the initial n-hexane decomposition first-order reaction rate constant value.
With a smaller initial catalytic activity, a satisfactory aromatic hydrocarbon yield cannot be obtained. Further, in order to stably obtain aromatic hydrocarbons for a long time, the initial catalytic activity is 0.2 to
It is preferably 2 (sec ^-1 ). The aromatic hydrocarbon yield here means the aromatic yield with respect to the non-aromatic hydrocarbons in the raw material.

In the present invention, the temperature of the inlet of the catalyst bed (hereinafter, often referred to as "reactor inlet") means the temperature of the catalyst bed at the portion where the raw material fluid first contacts the catalyst bed filled in the adiabatic reactor. The temperature at the outlet of the catalyst bed in the method of the present invention (hereinafter often referred to as “reactor outlet”) is
It is the temperature of the catalyst bed where the reaction mixture fluid finally comes into contact. The temperature of the catalyst bed referred to herein is 0 to 0, where the center of the catalyst bed is 0 and the distance from the center of the catalyst bed to the inner wall surface of the reactor is d in a plane perpendicular to the fluid flow direction.
Refers to a temperature between 8d.

In the method of the present invention, the maximum value of the temperature distribution of the catalyst bed with respect to the distance from the inlet to the outlet of the catalyst bed means the temperature from the inlet to the outlet of the catalyst bed and the temperature distribution curve It is the maximum temperature at the time of drawing, and the maximum value in the present invention is the maximum in a purely mathematical sense, as described in "Introduction to Analysis" edited by Yukinari Togi (Academic Book Publisher, 1983), pages 56-57. It is a value. In the process of the present invention, the minimum temperature of the catalyst bed is 450 ° C or higher and the maximum temperature is 650 ° C or lower.

In the present invention, the lowest temperature when the temperature from the inlet to the outlet of the catalyst bed is measured and the temperature distribution curve is drawn is the lowest value of the temperature distribution of the catalyst bed, and from the inlet of the catalyst bed The maximum temperature when the temperature to the outlet is measured and the temperature distribution curve is drawn is the maximum value of the temperature distribution in the catalyst bed. For the measurement of the temperature of the catalyst bed, including the inlet temperature and the outlet temperature of the catalyst bed, the energy management technology [heat management edition] edited by the editorial committee "Energy management technology" (Energy Saving Center, 1989), pages 384 to 389 are described. Use a thermoelectric thermometer.

In the method of the present invention, an aromatic hydrocarbon is used under reaction conditions satisfying the following requirements (2) to (4) using a zeolite-based catalyst having a catalytic activity satisfying the requirement (1). To manufacture. (2) The temperature of the catalyst bed is 450 to 650 ° C. (3) The catalyst bed has a temperature distribution with respect to the distance from the inlet to the outlet of the catalyst bed, and the temperature distribution has at least one maximum value. (4) The temperature at the outlet of the catalyst bed is within a range of ± 40 ° C with respect to the temperature at the inlet of the catalyst bed.

According to the method of the present invention as described above, aromatic hydrocarbons can be stably produced in high yield in a fixed bed adiabatic reactor. In addition to the activity of the zeolite catalyst satisfying the requirement of (1) above, if the temperature of the catalyst bed of the fixed bed adiabatic reactor satisfies the requirements of (2) to (4) above, that is, As shown in FIG. 3, the catalyst bed temperature 450
To 650 ° C., preferably 490 to 600 ° C., more preferably 500 to 580 ° C., the temperature distribution of the catalyst bed has at least one maximum value, and the difference between the catalyst bed outlet temperature and the inlet temperature is ± 40. Within the temperature range of 0 ° C., there is little coking to the catalyst bed, and operation can be stably performed for a long period of time while maintaining a high yield.

[0075] The ultra large value, the inlet from the weight hourly space velocity of the catalyst bed (WHSV) is preferably to have a range of up to a position of a catalyst comprising a 4hr ^-1, a WHSV from the position of the catalyst WHSV is 80Hr ^-1 It is more preferable to have the catalyst within the range of 4.5 hr ⁻¹ . The catalyst bed temperature of the above-mentioned isothermal reactor does not have a maximum value.

When the catalyst bed outlet temperature exceeds -40 ° C with respect to the catalyst bed inlet temperature, the aromatic hydrocarbon yield is low, and the catalyst bed outlet temperature is + 40 ° C with respect to the catalyst bed inlet temperature.
If it exceeds, the reaction zone becomes hot, coking increases, and the activity of the catalyst drops sharply, making stable operation difficult.
Further, when the temperature of the catalyst bed is lower than 450 ° C, the yield of aromatics obtained is low, and when it exceeds 650 ° C, coking increases and the activity of the catalyst sharply decreases, which makes stable operation difficult.

If the temperature of the catalyst bed of the fixed bed adiabatic reactor satisfies the above-mentioned requirements (2) to (4) in addition to the requirement (1) of the zeolite-based catalyst, the requirement (1) In comparison with the case where any one of (4) to (4) is not satisfied, the aromatic yield is high, and the coking is small, so that the operation can be stably performed for a long period of time.

[0078]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the method of the present invention will be described below with reference to FIGS. 1 and 2. In FIG. 1, 1 and 2 are fixed bed adiabatic reactors for producing aromatic hydrocarbons from light hydrocarbons. In the fixed bed adiabatic reactor 1, for example, a C ₄ fraction of a high temperature thermal decomposition product of a petroleum hydrocarbon such as naphtha, or a fraction obtained by removing butadiene or butadiene and i-butene from the C ₄ fraction. The raw material fluid 3, which is a fraction, is supplied to the fixed-bed adiabatic reactor 2 and a C ₅ fraction of a high temperature thermal decomposition product of petroleum hydrocarbons such as naphtha, or a diene from the C ₅ fraction. The raw material fluid 4, which is the removed fraction, is supplied.

The weight ratio of the raw material fluids 3 and 4 supplied is not particularly limited. For example, the fixed bed adiabatic reactor 1 is supplied with the raw material fluid 3 at a temperature of 450 to 650 ° C. in a weight hourly space velocity ( WHSV) 0.1-50 hr ^-1 , pressure is atmospheric pressure ~
It is supplied under the condition of 30 kg / cm ² · G, and the fixed bed adiabatic reactor 2 is supplied with the raw material fluid 4 having the same temperature as the raw material fluid 3.
The feed fluid 3 is fed to the fixed bed adiabatic reactor 1 at the same weight hourly space velocity (WHSV) and the same pressure. The reaction mixture fluids 5 and 6 produced in the fixed bed adiabatic reactors 1 and 2 are mixed to form a reaction mixture fluid 7
Becomes

In FIG. 2, 8 is a fixed bed adiabatic reactor which is the same as the fixed bed adiabatic reactors 1 and 2 in FIG. The same raw material fluid 9 as the raw material fluid 3 in FIG.
The raw material fluid 10 which is the same as the raw material fluid 4 in FIG. 1 is mixed at the same weight ratio as the supply weight ratio of the raw material fluids 3 and 4 in FIG. The raw material fluid 11 is supplied to the fixed bed adiabatic reactor 8 at the same inlet temperature and weight hourly space velocity (WHSV) as the conditions for supplying the raw material fluids 3 and 4 to the fixed bed adiabatic reactors 1 and 2 in FIG. ), At the same pressure. In this way, the reaction mixture fluid 12 is obtained.

In the method of the present invention, the aromatic hydrocarbon yield obtained by the embodiment described with reference to FIG. 2 is more important than the aromatic hydrocarbon yield obtained by the embodiment described with reference to FIG. Hydrogen yields are often higher. The method of the present invention is not limited to the above embodiments.

In the present invention, the pressure in the fixed bed adiabatic reactor during the cyclization reaction is from atmospheric pressure to 30 kg / cm ² · G, and the light hydrocarbon raw material is supplied at a weight hourly space velocity (WH).
It is preferable that the SV is supplied at 0.1 to 50 hr ^-1 .
The pressure in the reactor means the average pressure of the reactor, which is the average value of the pressure at the inlet and the pressure at the outlet of the reactor. For the measurement of the inlet pressure and the outlet pressure of the reactor, the energy management technique [heat management edition] edited by the editorial committee, "energy management technique" (Energy Saving Center, 1989)
A pressure gauge described on pages 398 to 406 is used.

The weight hourly space velocity (WHSV) of the raw material fluid in the reactor is the value obtained by the following equation. WHSV (hr ^-1 ) = raw material fluid supply mass flow rate (g / hr) /
Amount of catalyst (g) In the above equation, the mass flow rate of the raw material fluid is determined by using the flowmeter described in “Energy Management Technology” (Energy Management Center, 1989) pp. taking measurement.

In the process of the present invention, the reaction mixture rich in aromatic hydrocarbons is converted into a product mainly consisting of aromatic hydrocarbons by using a gas-liquid separation tank and optionally a distillation column as described later. And a product mainly consisting of non-aromatic hydrocarbons. In this case, the former product may be used as it is, or may be subjected to dealkylation and the like. Also, the latter product is preferably recycled or supplied to another process.

Hereinafter, the method of the present invention will be described in detail with reference to the accompanying drawings showing the preferred embodiments of the present invention. FIG. 5 is a flow sheet showing one embodiment of separation of the reaction mixture in the method of the present invention. In FIG.
The raw material fluid 17 is heated in the heating furnace 13, and the heated raw material fluid 18 is supplied to the fixed bed adiabatic reactor 14 containing a zeolite-based catalyst to generate a reaction mixture fluid 19. Here, the raw material fluid 17 is a light hydrocarbon containing at least one selected from the group consisting of the above-mentioned olefin and paraffin.

Specific examples of the light hydrocarbons include C ₄ fraction of high temperature thermal decomposition products of petroleum hydrocarbons such as naphtha,
Or a fraction obtained by removing butadiene or butadiene and i-butene from the C ₄ fraction; a C ₅ fraction of a high temperature thermal decomposition product of petroleum hydrocarbons; or a fraction obtained by removing dienes from the C ₅ fraction; Pyrolysis gasoline; Raffinate obtained by extracting aromatic hydrocarbons from pyrolysis gasoline; FCC-LPG; FC
C cracked gasoline; raffinate obtained by extracting aromatic hydrocarbons from reformate; Coker's LPG; straight run naphtha. The heat of the reaction mixture fluid 19 is the heat of the raw material fluid 1.
It may be used for preheating of No. 7.

The reaction mixture fluid 19 is a heat exchanger 1 for cooling.
After cooling at 5, the cooled reaction mixture fluid 20
Is a target product A rich in aromatic hydrocarbons and a product B mainly containing non-aromatic hydrocarbons consisting of by-product hydrogen and paraffins having 1 to 5 carbon atoms, olefins and naphthenes. A separation including a gas-liquid separation tank, and optionally a distillation column (which can further increase the purity of the product separated by the gas-liquid separation tank) by utilizing the difference in boiling points between the two. By means 16 the products A and B
Is separated into The reaction mixture fluid 19 may be cooled by the heat exchanger 15 for cooling as described above, or may be cooled by the raw material fluid 17 and further cooled by the heat exchanger 15 for cooling.

FIG. 6 is a flow sheet showing another embodiment of separation of the reaction mixture in the method of the present invention. Figure 6
As shown in FIG. 5, the reaction mixture fluid 19 is produced from the raw material fluid 17 by the same procedure as shown in FIG. The produced reaction mixture fluid 19 may be cooled by the heat exchanger 15 for cooling, or may be cooled by the raw material fluid 17 and further cooled by the heat exchanger 15 for cooling. The cooled reaction mixture fluid 20 contains a target product A rich in aromatic hydrocarbons, and a product C mainly containing non-aromatic hydrocarbons having a carbon number of 4 and 5 as by-products, hydrogen and 1-3 carbons
Using the difference in the boiling points of the product D mainly composed of non-aromatic hydrocarbons, the separation means 16 including a gas-liquid separation tank and, in some cases, a distillation column produces the products A, C
And D. Note that the aromatic hydrocarbon-rich product A shown in FIG. 5 and the aromatic hydrocarbon-rich product A shown in FIG. 6 may have different compositions.

Refrigerants used in the heat exchanger 15 for cooling in FIGS. 5 and 6 include cooling water, propylene, ethylene, fluorine compounds and the like, but in order to reduce equipment investment and required energy, A propylene or ethylene refrigerant system produced in an ethylene production process including a high temperature pyrolysis unit for petroleum hydrocarbons and used as a refrigerant in the process may be used. in this case,
In addition, the C ₄ fraction and C produced in the ethylene production process
_{A by-} product containing ₅ fractions may be used as at least a part of the light hydrocarbon feedstock.

Further, as the raw material fluid 17 in FIGS. 5 and 6, petroleum hydrocarbons were pyrolyzed at a high temperature by a steam cracking apparatus and pyrolyzed gasoline separated by a pyrolysis gasoline separator was separated by a C ₅ separator. Separation means 1 using ₅ fractions and separating the reaction mixture 19 obtained
As C6, the C ₅ separator may be used. Note that the gas-liquid separation tank referred to here is “Process Equipment Structural Design Series 2 Towers” edited by Japan Society of Chemical Engineering (Maruzen, Japan, 197).
0) means those described on pages 73 to 130, and the distillation column refers to those described on pages 2 to 4 of "Process Equipment Structural Design Series 2 Tower Tanks" (Maruzen, 1970, Japan) edited by the Chemical Engineering Society. What is a heating furnace? “Process equipment structure design series 4 heating furnace” edited by Japan Chemical Engineering Association (Maruzen, 1970) 1-4
It means a tube type heating furnace as described in the page.

In the method of the present invention, at least a part of the product B obtained by purifying and separating the target aromatic compound by the above method, or at least one of the products C and D is selected. At least a part is recycled, and the recycled product is mixed with the raw material fluid 17, or the recycled product is mixed with the raw material fluid 17.
May be mixed with the raw material fluid 18 obtained by heating in the heating furnace 13. Alternatively, the recycled product may be fed directly to the middle portion of the catalyst bed in the reactor 14 rather than to the inlet of the reactor 14 so that the temperature of the catalyst bed in the reactor 14 is from (2) to The requirement (4) may be satisfied.

In the method of the present invention, as described above, for example, a typical example in which at least a part of the product B or at least a part of at least one selected from C and D is recycled to the reactor is shown. 9 shows. That is,
FIG. 9 is a flow sheet showing an embodiment of recycling of the reaction product in the method of the present invention, in which the fresh feed 43 is introduced into the reactor 40, and the obtained reaction product is purified by the purifying / separating means 41. Is obtained by separating the aromatic hydrocarbons to be reacted with non-aromatic hydrocarbons as unreacted raw materials or by-products, recycling the obtained non-aromatic hydrocarbons, and mixing the recycled component 42 with the fresh feed 43. The mixture 44 is reintroduced into the reactor 40.

In the method of the present invention, at least a part of the product B obtained by purifying and separating the target aromatic compound by the above method, or the product C and the product D.
At least a part of at least one selected from the above is supplied to a high temperature thermal decomposition apparatus for petroleum hydrocarbons in the ethylene process, so that ethylene, propylene, C ₄ fraction, C ₅ fraction in an ethylene plant including the high temperature thermal decomposition apparatus.
Fractions and active products such as aromatic hydrocarbons such as benzene, toluene, xylene can also be recovered.

In the method of the present invention, the aromatic hydrocarbon-rich product A purified and separated by the above method can be treated by at least one method selected from the following methods. A method for producing benzene by supplying the product A to a dealkylation reactor to carry out hydrodealkylation reaction; introducing the product A into a distillation apparatus, an extraction apparatus or an extractive distillation apparatus to produce benzene, toluene, xylene. (Hereinafter, these three substances are collectively referred to as "BTX"); a method of treating the product A in a disproportionation reactor or an isomerization reactor; and blending the product A with gasoline. Method.

The dealkylation reactor referred to here is "New Petrochemical Process" edited by Japan Petroleum Institute (Kobunsho, Japan, 198)
6) It means a reactor used for any of the catalytic and thermal dealkylation methods as described on pages 145 to 155. A distillation apparatus means an apparatus used for a distillation system as described in “Process Design Series 3, Design centering on decomposition / heating / distillation” edited by Japan Society of Chemical Engineering (Maruzen, 1974, Japan), pages 183-206. To do. The disproportionation reaction device means a device used for the disproportionation reaction as described in "New Petrochemical Process" edited by Japan Petroleum Institute (Koyuki Shobo, Japan, 1986), pages 100-115.

The isomerization reactor is "New Petrochemical Process" edited by Japan Petroleum Institute (Kobunsho, Japan, 1986) 69-8.
It means an apparatus used for an isomerization reaction as described on page 8. The extractor and extractive distillation apparatus are methods for obtaining aromatic hydrocarbons such as benzene, toluene, and xylene with high purity as “Process Design Series 3,” edited by the Chemical Engineering Association.
Design centered on decomposition, heating, and distillation ”(Maruzen, Japan,
1974) pages 206-213,
It refers to those used in extractive distillation and azeotropic distillation.

In the method of the present invention, the generation of carbonaceous matter (coke) on the zeolite-based catalyst accompanying the cyclization reaction for producing aromatic hydrocarbons can be greatly reduced.
However, if coke accumulates on the zeolite-based catalyst,
The supply of light hydrocarbon feedstock to the fixed bed adiabatic reactor is temporarily stopped, and the coke accumulated on the zeolite-based catalyst during the cyclization reaction is burned and removed in the catalyst regeneration zone using the oxygen-containing inert gas. By doing so, the zeolite-based catalyst can be regenerated.

The exhausted combustion gas from the catalyst regeneration zone may be released into the atmosphere as it is, or may be recycled by using a circulation compressor as shown below. In either case, it is more preferable to use the oxygen-containing inert gas after contacting it with a moisture adsorbent to reduce the amount of moisture. Air can be mentioned as a typical example of the oxygen-containing inert gas.

When the exhaust combustion gas from the catalyst regeneration zone is recycled, the exhaust combustion gas is recycled to the catalyst regeneration zone through a heating furnace by using a circulation compressor, and then the catalyst regeneration zone and circulation compression are performed. It is preferable to form a combustion gas circulation system in which a machine and a heating furnace are connected in this order by piping.

In this case, a fresh oxygen-containing inert gas is introduced into the first inlet located between the outlet of the catalyst regeneration zone of the combustion gas circulation system and the inlet of the heating furnace with respect to the circulation amount of the combustion gas. 0.05 to 50% by volume, preferably 2.5 to 1
An amount of 0% by volume, the exhaust combustion gas from the catalyst regeneration zone being substantially equal to the amount of fresh oxygen-containing inert gas supplied to the first inlet before reaching the furnace. Can be released out of the system.
Regarding the above-mentioned fresh oxygen-containing inert gas, the oxygen content of the combustion gas introduced into the catalyst regeneration zone is 0.0
The supply amount and oxygen content of the fresh oxygen-containing inert gas are adjusted so as to be 1 to 10% by volume, preferably 0.5 to 2% by volume.

Further, a fresh inert gas containing no oxygen is added to the same inlet as the above-mentioned first inlet or between the outlet of the catalyst regeneration zone of the combustion gas circulation system and the inlet of the heating furnace. An amount of 10% by volume or less, preferably 5% by volume or less with respect to the circulation amount of the combustion gas is supplied to a second inlet which is an inlet provided separately from the exhaust gas from the catalyst regeneration zone. It is further provided that the combustion gas is additionally discharged out of the system before reaching the heating furnace by an amount substantially equal to the amount of the above-mentioned oxygen-free fresh inert gas supplied to the second inlet. preferable. By this operation,
It is possible to suppress an increase in the steam partial pressure of the combustion gas flowing into the catalyst regeneration zone.

As described above, when fresh inert gas containing no oxygen is supplied in addition to the fresh oxygen-containing inert gas supplied to the combustion gas circulation system, the combustion gas circulation system is supplied from different inlets respectively. These may be supplied, or these gases may be mixed in advance and supplied from one inlet into the fuel gas circulation system.

FIG. 7 is a flow sheet showing an embodiment of the regeneration of the zeolite-based catalyst in the method of the present invention. In the combustion gas circulation system of FIG. 7, fresh oxygen-containing inert gas 28 and oxygen-free fresh inert gas 27 are supplied into the combustion gas circulation system from the first and second inlets, respectively.

In FIG.
It is heated to 600 ° C., preferably 390 to 580 ° C., more preferably 420 to 480 ° C., and 0.05 to 50% by volume, preferably 2.5 to the circulation amount of the combustion gas.
Fresh oxygen-containing inert gas 28 (for example, air) of -10% by volume has an oxygen concentration of 0.01-10% by volume in the combustion gas 24 flowing into the catalyst regeneration zone 21 containing the zeolite-based catalyst having coke attached. A combustion gas comprising a fresh oxygen-containing inert gas 28 introduced into the combustion gas circulation system so as to be preferably 0.5 to 2% by volume and the exhaust combustion gas 25 discharged from the catalyst regeneration zone 21. But,
It is supplied to the heating furnace 23 again using the circulation compressor 22.

Further, before the combustion gas to be compressed reaches the circulation compressor 22, or before the compressed combustion gas leaves the circulation compressor 22 and reaches the heating furnace 23 (not shown). Introducing 10% by volume or less, preferably 5% by volume or less, of oxygen-free fresh inert gas 27 with respect to the circulation amount of the combustion gas.

Before the combustion gas to be compressed reaches the circulation compressor 22, or before the compressed combustion gas leaves the circulation compressor 22 and reaches the heating furnace 23 (not shown), Of substantially the same as the total amount of supply of the fresh oxygen-containing inert gas 28 and the oxygen-free fresh inert gas 27, for example, 0.05 to 60% by volume, preferably 0. It is possible to keep the total pressure in the system constant by releasing a part (shown by reference numeral 26) of the exhaust combustion gas 25 from the catalyst regeneration zone 21 of 05 to 20% by volume to the outside of the system. it can.

Incidentally, a part of the discharge port for the exhaust combustion gas is
The oxygen-containing inert gas and the oxygen-free inert gas may be provided downstream of the supply ports (not shown). By the above operation, it is possible to suppress an increase in the partial pressure of water vapor in the combustion gas flowing into the catalyst regeneration zone 21 and significantly suppress a decrease in the activity of the catalyst.

It is more preferable that the combustion gas discharged from the circulation compressor 22 is brought into contact with the moisture adsorbent before being introduced into the heating furnace 23 to reduce the amount of moisture. The inert gas is selected from those other than alcohol, ether, etc., which generate H ₂ O upon contact with zeolite, but nitrogen is more preferable.

In the present invention, the fixed bed adiabatic reactor can be used not only for the catalytic cyclization reaction but also as a catalyst regeneration reactor for the combustion gas circulation system used for catalyst regeneration. In this case, the catalytic cyclization reaction system and the combustion gas circulation system share one reactor which functions as an adiabatic reactor for catalytic cyclization reaction in the former case and as a catalyst regeneration reactor in the latter case. It will be.

That is, after the catalytic cyclization reaction, a valve provided appropriately is operated to disconnect the adiabatic reactor from the catalytic cyclization reaction system, and the combustion gas used for regeneration of the catalyst as shown in FIG. A closed circulation system is formed by connecting to the circulation system and incorporating it into the circulation system, and the adiabatic reactor is used as a catalyst regeneration reactor (note that two reactors are used as in the above two-column switching reactor). If used, or likewise if more than two reactors are used, at least one catalytic cyclization reaction system and at least one combustion gas circulation system comprising a plurality of reactors is suitably formed by switching valves. Provide an appropriate valve so that you can).

Alternatively, the catalyst used for the catalytic cyclization reaction of the raw material fluid is taken out from the adiabatic reactor, moved to a separately provided catalyst regeneration zone, and regenerated by a combustion gas circulation system as shown in FIG. Good. Similarly, the heating furnace used for heating the raw material in the catalytic cyclization reaction may be used as the heating furnace for the combustion gas in the combustion gas circulation system.

Further, the combustion gas to be compressed by the circulation compressor 22 may be cooled, and the compressed combustion gas may be heated before reaching the heating furnace 23. In this case, cooling and heating can be carried out using at least one heat exchanger. Here, the combustion gas to be compressed by the circulation compressor 22 is cooled in order to increase the compression efficiency of the circulation compressor 22, and the heating of the compressed combustion gas before reaching the heating furnace 23 is performed by This is performed to reduce the load on the heating furnace 23.

For heat exchange, a pipe from the outlet of the catalyst regeneration zone to the inlet of the circulation compressor and a pipe from the outlet of the circulation compressor to the inlet of the heating furnace are connected to one heat exchanger (not shown). It may be arranged to pass through and cooling and heating may be performed in one heat exchanger. In addition, a heat exchanger (not shown) for cooling and heating is provided in the pipe from the outlet of the catalyst regeneration zone to the inlet of the circulation compressor and in the pipe from the outlet of the circulation compressor to the inlet of the heating furnace, respectively. Alternatively, cooling and heating may be performed by separate heat exchangers.

In the process of the present invention, the steam treatment of the substantially fresh zeolite-based catalyst includes a steam treatment reactor, a circulation compressor, a heating furnace and at least one heat exchanger connected by pipes. It can be carried out using a steam circulation system. In this case, it is preferable to use the steam treatment reactor as an adiabatic reactor used for the catalytic cyclization reaction. Further, it is preferable to utilize this steam circulation system as a combustion gas circulation system for regenerating the above-mentioned zeolite catalyst.

In that case, the steam treatment reactor is used as it is as a catalyst regeneration reactor including a catalyst regeneration zone in the combustion gas circulation system, or the steam treatment reactor is used as the catalyst regeneration reactor. In place of the steam used in the steam circulation system, a combustion gas used in the combustion gas circulation system is used. In the present invention, it is preferable to use the steam treatment reactor also as the adiabatic reactor and the catalyst regeneration reactor.

The circulating compressor referred to here is the positive displacement compressor described in "Mechanical Engineering Handbook, Revised 6th Edition" edited by the Japan Society of Mechanical Engineers (Japan Society of Mechanical Engineers, 1977), 10th edition, Air Machine, pages 11-46. It means a machine or a positive displacement fan, a centrifugal compressor or a centrifugal blower, an axial compressor or an axial blower, and the like.

[0117]

EXAMPLES The embodiments of the present invention will now be specifically described with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

Example 1 60 parts by weight of ammonium ion type ZSM-5 crystalline aluminosilicate (Si / Al atomic ratio 46), 15 parts by weight of γ-alumina and 25 parts by weight of zinc nitrate were kneaded, and extrusion molding was carried out. It was formed into a diameter of 1.6 mm and a length of 4 to 6 mm. Then, after drying at 120 ° C. for 4 hours, it was calcined at 500 ° C. for 3 hours to obtain a ZSM-5 zeolite molded catalyst containing 10% by weight of zinc. Next, this catalyst was packed in a fixed bed one-stage adiabatic reactor as a catalyst bed, and a steam-nitrogen mixed gas containing 40% by volume of steam was supplied at a pressure of 1 kg / cm ² · G and a temperature of 650.
The catalyst bed was supplied / circulated for 5 hours under the condition of ° C.

Next, in order to determine the initial catalytic activity of this zeolite shaped catalyst, an isothermal n-hexane conversion reaction test was conducted using the isothermal reactor shown in FIG. Specifically, according to the method described above, atmospheric pressure, temperature 500 ° C.,
Under the condition of weight hourly space velocity (WHSV) of 4 hr ⁻¹ , the average initial n-hexane decomposition first-order reaction rate constant for the gas oil sampling time of 0.25 hours was calculated to be 0.28 (sec
^-1 ).

Next, the C ₅ fraction shown in Table 2 and the C ₄ fraction shown in Table 1 were adjusted to 3 so that the unsaturated hydrocarbon / saturated hydrocarbon weight ratio was within the range of 0.43 to 2.33. The raw material (unsaturated hydrocarbon / saturated hydrocarbon weight ratio of 1.54) mixed with 7 (weight ratio) is heated to 530 ° C. and fed to the fixed bed one-stage adiabatic reactor to carry out the catalytic cyclization reaction. I did. The reaction results after 10 hours and 5 days from the start of the reaction are shown in Table 3 together with the reaction conditions.
Shown in

Comparative Example 1 The same operation as in Example 1 was carried out except that the C ₅ fraction (unsaturated hydrocarbon / saturated hydrocarbon weight ratio 0.37) shown in Table 2 was used as the raw material. 10 hours after the start of the reaction and 5
The reaction results after day are shown in Table 3 together with the reaction conditions.

Comparative Example 2 The same operation as in Example 1 was carried out except that the C ₄ fraction (unsaturated hydrocarbon / saturated hydrocarbon weight ratio 3.00) shown in Table 1 was used as the raw material. 10 hours after the start of the reaction and 5
The reaction results after day are shown in Table 3 together with the reaction conditions. From the results of Comparative Examples 1 and 2 shown in Table 3, if the reaction conditions do not satisfy all the requirements (1) to (4) of the present invention, the yield becomes low and stable operation cannot be performed. It turns out that there are some problems.

Example 2 The same operation as in Comparative Example 2 was carried out except that the pressure in the fixed bed one-stage adiabatic reactor was set to 1 kg / cm ² · G. The reaction results after 10 hours and 3 days after the start of the reaction are shown in Table 4 together with the reaction conditions.
Shown in In Table 4, 10 hours after the start of the reaction of Comparative Example 2 and 3
Results after days are also shown.

Example 3 A C ₄ fraction (unsaturated hydrocarbon / saturated hydrocarbon weight ratio 3.00) shown in Table 1 was heated to 530 ° C. to obtain a catalyst bed obtained by the same method as in Example 1. It is fed to a packed fixed bed one-stage adiabatic reactor, and the reaction product obtained there is used in a gas-liquid separation tank and a distillation column to produce a product A rich in aromatic hydrocarbons,
After separating into a product C mainly composed of a non-aromatic hydrocarbon having 4 and 5 carbon atoms and a product D mainly composed of hydrogen and a non-aromatic hydrocarbon having 1 to 3 carbon atoms, the product C is It was supplied to the fixed bed single-stage adiabatic reactor and recycled. Also in this case,
The reaction conditions satisfied all the requirements (1) to (4) of the present invention. The reaction results after 10 hours and 3 days after the start of the reaction are shown in Table 4 together with the reaction conditions. From Table 4, it can be seen that regardless of the raw material composition, stable operation with high yield is possible if the reaction conditions satisfy all the requirements (1) to (4) of the present invention.

Comparative Example 3 60 parts by weight of ammonium ion type ZSM-5 crystalline aluminosilicate (Si / Al atomic ratio 46), 15 parts by weight of γ-alumina and 25 parts by weight of zinc nitrate were kneaded, and then extrusion-molded, It was formed into a diameter of 1.6 mm and a length of 4 to 6 mm. Then, after drying at 120 ° C. for 4 hours, it was calcined at 500 ° C. for 3 hours to obtain a ZSM-5 zeolite molded catalyst containing 10% by weight of zinc. Next, this catalyst was packed in a fixed bed one-stage adiabatic reactor as a catalyst bed, and a steam-nitrogen mixed gas containing 40% by volume of steam was supplied at a pressure of 1 kg / cm ² · G and a temperature of 650.
The catalyst bed was supplied and flowed for 1 hour under the condition of ° C.

Next, an isothermal n-hexane conversion reaction test of this zeolite-molded catalyst was carried out in the same manner as in Example 1. The initial n-hexane decomposition first-order reaction rate constant was 0.55 ( sec ^-1 ). Next, the unsaturated hydrocarbon / saturated hydrocarbon weight ratio is out of the range of 0.43 to 2.33, and the C ₅ fraction shown in Table 2 (unsaturated hydrocarbon / saturated hydrocarbon weight ratio 0.37). Was heated to 530 ° C. and fed to the fixed bed single stage adiabatic reactor described above. The reaction results after 10 hours from the start of the reaction are shown in Table 5 together with the reaction conditions.

Comparative Example 4 The same operation as in Comparative Example 3 was carried out except that the C ₄ fraction (unsaturated hydrocarbon / saturated hydrocarbon weight ratio 3.00) shown in Table 1 was used. The reaction results after 10 hours from the start of the reaction are shown in Table 5 together with the reaction conditions.

Example 4 A raw material obtained by mixing the C ₅ fraction shown in Table 2 and the C ₄ fraction shown in Table 1 in a ratio of 3: 7 (weight ratio) (unsaturated hydrocarbon / saturated hydrocarbon weight ratio 1.54). The same operation as in Comparative Example 3 was carried out except that was used. The reaction results after 10 hours from the start of the reaction are shown in Table 5 together with the reaction conditions.

From Table 5, under the above conditions, the C ₅ fraction 10
Product obtained by reacting 0% of raw materials (Comparative Example 3)
And a product obtained by reacting a raw material containing 100% of C ₄ fraction (Comparative Example 4) in a weight ratio of 3: 7, respectively, the aromatic yield (54.7% by weight) (hereinafter, “Calculated aromatic yield”), the C ₅ fraction and C
It can be seen that the aromatic yield (56.7% by weight) obtained by reacting a mixture of ₄ fractions in a weight ratio of 3: 7 is higher. The above calculated aromatic yield is “aromatic yield of Comparative Example 3 × 0.3 + aromatic yield of Comparative Example 4 × 0.7”.
It was obtained by the calculation of. In addition, Table 5 shows the aromatic yields 5 days after the start of the reaction for Comparative Examples 3 and 4 and Example 4. From these results, stable operation with high yield is possible under the conditions of Example 4. It can be seen that it is.

Comparative Example 5 A ZSM-5 zeolite molded catalyst obtained by the same method as in Comparative Example 3 was charged as a catalyst bed in a fixed bed one-stage adiabatic reactor, and a steam-nitrogen mixed gas containing 40% by volume of steam was added. ,
Under the conditions of a pressure of 1 kg / cm ² · G and a temperature of 650 ° C., the catalyst bed was supplied and flowed for 5 hours. Next, an isothermal n-hexane conversion reaction test of this zeolite shaped catalyst was carried out in the same manner as in Example 1. The initial n-hexane decomposition first-order reaction rate constant was 0.28 (sec ^-1 ). there were. Next, the unsaturated hydrocarbon / saturated hydrocarbon weight ratio is 0.43 to 2.33.
Of the C ₅ fraction (unsaturated hydrocarbon / saturated hydrocarbon weight ratio 0.37) shown in Table 2, which is outside the range of
It was fed to the above fixed bed one-stage adiabatic reactor. Reaction start 1
The reaction results after 0 hours are shown in Table 5 together with the reaction conditions.

Comparative Example 6 The same operation as in Comparative Example 5 was carried out except that the C ₄ fraction (unsaturated hydrocarbon / saturated hydrocarbon weight ratio 3.00) shown in Table 1 was used. The reaction results after 10 hours from the start of the reaction are shown in Table 5 together with the reaction conditions.

Example 5 A raw material obtained by mixing the C ₅ fraction shown in Table 2 and the C ₄ fraction shown in Table 1 in a ratio of 3: 7 (weight ratio) (unsaturated hydrocarbon / saturated hydrocarbon weight ratio 1.54). The same operation as in Comparative Example 5 was carried out except that was used. The reaction results after 10 hours from the start of the reaction are shown in Table 5 together with the reaction conditions. As shown in Table 5, the aromatic yield of Example 5 (51.2% by weight) was calculated from the aromatic yields of Comparative Example 5 and Comparative Example 6 (49.3).
% By weight).

Comparative Example 7 The ZSM-5 zeolite molded catalyst obtained by the same method as in Comparative Example 3 was subjected to steam heat treatment under the same conditions as in Comparative Example 5.
Next, an isothermal n-hexane conversion reaction test of this zeolite molded catalyst was carried out in the same manner as in Example 1,
The initial n-hexane decomposition first-order reaction rate constant was 0.28 (s
ec ^-1 ). Next, the C ₅ fraction (unsaturated hydrocarbon / saturated hydrocarbon weight ratio 0.37) shown in Table 2 was heated to 450 ° C. and supplied to the fixed bed one-stage adiabatic reactor. The reaction results after 10 hours from the start of the reaction are shown in Table 5 together with the reaction conditions.

Comparative Example 8 The same operation as in Comparative Example 7 was carried out except that the C ₄ fraction (unsaturated hydrocarbon / saturated hydrocarbon weight ratio 3.00) shown in Table 1 was used. The reaction results after 10 hours from the start of the reaction are shown in Table 5 together with the reaction conditions.

Comparative Example 9 The ZSM-5 zeolite molded catalyst obtained by the same method as in Comparative Example 3 was subjected to steam heat treatment under the same conditions as in Comparative Example 5.
Next, the unsaturated hydrocarbon / saturated hydrocarbon weight ratio is 0.43.
To 2.33, a raw material (unsaturated hydrocarbon / saturated hydrocarbon weight) obtained by mixing the C ₅ fraction shown in Table 2 and the C ₄ fraction shown in Table 1 in a ratio of 3: 7 (weight ratio). Ratio 1.54) to 4
It was heated to 50 ° C. and fed to the above fixed bed single stage adiabatic reactor. The reaction results after 10 hours from the start of the reaction are shown in Table 5 together with the reaction conditions.

As shown in Table 5, an aromatic yield (43.9% by weight) obtained by reacting a mixture of a C ₅ fraction and a C ₄ fraction 3: 7 under the conditions of Comparative Example 9 ) Is Comparative Example 7
It is lower than the calculated aromatic yield (44.7% by weight) obtained from the aromatic yield of Comparative Example 8 and the aromatic yield of Comparative Example 8.

Example 6 60 parts by weight of ammonium ion type ZSM-5 crystalline aluminosilicate (Si / Al atomic ratio 46), 15 parts by weight of γ-alumina and 25 parts by weight of zinc nitrate were kneaded, and then extrusion-molded, It was formed into a diameter of 1.6 mm and a length of 4 to 6 mm. Then, after drying at 120 ° C. for 4 hours, it was calcined at 500 ° C. for 3 hours to obtain a ZSM-5 zeolite molded catalyst containing 10% by weight of zinc. Next, this catalyst was packed in a fixed bed one-stage adiabatic reactor as a catalyst bed, and a steam-nitrogen mixed gas containing 40% by volume of steam was supplied at a pressure of 1 kg / cm ² · G and a temperature of 650.
The catalyst bed was supplied / circulated for 5 hours under the condition of ° C.

Next, the isothermal n
When the hexane conversion reaction test was carried out in the same manner as in Example 1, the initial n-hexane decomposition first-order reaction rate constant was 0.28 (sec ⁻¹ ). Next, a raw material in which the C ₅ fraction shown in Table 2 and the C ₄ fraction shown in Table 1 were mixed in a ratio of 6: 4 (weight ratio) (unsaturated hydrocarbon / saturated hydrocarbon weight ratio 0.86)
Was heated to 530 ° C. and fed to the fixed bed single stage adiabatic reactor described above. The reaction results after 10 hours from the start of the reaction are shown in Table 6 together with the reaction conditions.

Comparative Example 10 The same operation as in Example 6 was carried out except that the steam heat treatment time of the zeolite catalyst was set to 40 hours so that the initial catalyst activity was less than 0.2 (sec ⁻¹ ). Reaction start 10
The reaction results after the lapse of time are shown in Table 6 together with the reaction conditions.

Example 7 46.4 parts by weight of ammonium ion type ZSM-5 crystalline aluminosilicate (Si / Al atomic ratio 46), 11.6 parts by weight of γ-alumina and 42 parts by weight of zinc aluminate were kneaded and then extruded. Molded, diameter 1.6 mm, length 4
Molded to ~ 6 mm. Then, after drying at 120 ° C. for 4 hours,
ZSM containing 20% by weight of zinc after firing at 500 ° C for 3 hours
-5 zeolite shaped catalyst was obtained.

Next, this catalyst was packed in a fixed bed one-stage adiabatic reactor as a catalyst bed, and steam containing 40% by volume of steam was added.
The nitrogen mixed gas was supplied and passed through the catalyst bed for 5 hours under the conditions of a pressure of 1 kg / cm ² · G and a temperature of 650 ° C. Next, Table 2
The raw material (unsaturated hydrocarbon / saturated hydrocarbon weight ratio 0.86) in which the C ₅ fraction shown in Table 1 and the C ₄ stream shown in Table 1 were mixed in a ratio of 6: 4 (weight ratio) was heated to 530 ° C. Was fed to the fixed bed single-stage adiabatic reactor. The reaction results 10 hours after the start of the reaction are shown in Table 6 together with the reaction conditions.

Comparative Example 11 Na was adjusted so that the concentration of remaining Na was 3000 wtppm.
Type ZSM-5 crystalline aluminosilicate (Si / Al atomic ratio 46) by ion exchange to form ammonium ion type Z
SM-5 crystalline aluminosilicate. The ammonium ion type ZSM-5 crystalline aluminosilicate 60
After kneading 15 parts by weight of .gamma.-alumina and 25 parts by weight of zinc nitrate, extrusion molding was carried out to form a diameter of 1.6 mm and a length of 4 to 6 mm. Then, after drying at 120 ° C. for 4 hours, firing at 500 ° C. for 3 hours is performed, and Z containing 10% by weight of Z
An SM-5 zeolite shaped catalyst was obtained. In addition, N in the catalyst
The a concentration was determined by placing the catalyst in a 1N-HCl aqueous solution, heating it for 5 minutes and then filtering the filtrate, and then measuring the filtrate with an atomic absorption spectrometer (A, manufactured by Shimadzu Corporation).
A-640-12).

Next, this catalyst was packed in a fixed bed one-stage adiabatic reactor as a catalyst bed, and steam containing 40% by volume of steam was added.
The nitrogen mixed gas was supplied and passed through the catalyst bed for 5 hours under the conditions of a pressure of 1 kg / cm ² · G and a temperature of 650 ° C. Next, an isothermal n-hexane conversion reaction test of this zeolite-molded catalyst was carried out in the same manner as in Example 1.
The hexane decomposition first-order reaction rate constant was 0.05 (sec ⁻¹ ).

Next, the C ₅ fraction shown in Table 2 and the C ₅ fraction shown in Table 1
A raw material (unsaturated hydrocarbon / saturated hydrocarbon weight ratio 0.86) in which ₄ fractions were mixed in a ratio of 6: 4 (weight ratio) was heated to 530 ° C. and supplied to the fixed bed one-stage adiabatic reactor. The reaction results after 10 hours from the start of the reaction are shown in Table 7 together with the reaction conditions.
The Na concentration of the catalyst used in Example 6 was 110 wtppm when measured by the same method as above. The results of Example 6 including the Na concentration are also shown in Table 7 for comparison.

Example 8 The reaction product obtained by the catalytic cyclization reaction was mixed with a product A rich in aromatic hydrocarbons using a gas-liquid separation tank and a distillation column.
The product C mainly composed of non-aromatic hydrocarbons having 4 and 5 carbon atoms and the product D mainly composed of hydrogen and non-aromatic hydrocarbons having 1 to 3 carbon atoms are separated, and the product C is fixed. The same operation as in Example 6 was carried out except that the material was supplied to the one-stage floor adiabatic reactor and recycled.

That is, ammonium ion type ZSM-5 crystalline aluminosilicate (Si / Al atomic ratio 46) 60
After kneading 15 parts by weight of .gamma.-alumina and 25 parts by weight of zinc nitrate, extrusion molding was carried out to form a diameter of 1.6 mm and a length of 4 to 6 mm. Then, after drying at 120 ° C. for 4 hours, firing at 500 ° C. for 3 hours is performed, and Z containing 10% by weight of Z
An SM-5 zeolite shaped catalyst was obtained.

Next, this catalyst was packed in a fixed-bed one-stage adiabatic reactor as a catalyst bed, and steam containing 40% by volume of steam was added.
The nitrogen mixed gas was supplied and passed through the catalyst bed for 5 hours under the conditions of a pressure of 1 kg / cm ² · G and a temperature of 650 ° C. Next, an isothermal n-hexane conversion reaction test of this zeolite-molded catalyst was carried out in the same manner as in Example 1.
The hexane decomposition first-order reaction rate constant was 0.28 (sec ⁻¹ ).

Next, the C ₅ fraction shown in Table 2 and the C ₅ fraction shown in Table 1
A raw material (unsaturated hydrocarbon / saturated hydrocarbon weight ratio 0.86) in which ₄ fractions were mixed in a ratio of 6: 4 (weight ratio) was heated to 530 ° C. and supplied to the fixed bed one-stage adiabatic reactor, The reaction product thus obtained was subjected to a gas-liquid separation tank and a distillation column to produce a product A rich in aromatic hydrocarbons, a product C mainly composed of non-aromatic hydrocarbons having 4 and 5 carbon atoms, and hydrogen. And carbon number 1
After separating into a product D mainly composed of non-aromatic hydrocarbons of 3, the product C was supplied to the fixed bed one-stage adiabatic reactor and recycled. A propylene refrigerant produced in an ethylene production process and used as a refrigerant was commonly used as a refrigerant for separating the products A, C, and D. The reaction results after 10 hours from the start of the reaction are shown in Table 8 together with the reaction conditions. As shown in Table 8, in Example 8, C ₆ to
High C ₉ aromatic yield.

Example 9 The product C mainly composed of non-aromatic hydrocarbons having 4 and 5 carbon atoms was fed to a tubular pyrolysis apparatus without being recycled to a fixed bed one-stage adiabatic reactor to generate heat. The same operation as in Example 8 was performed except that the decomposition was performed. That is, the ZSM-5 zeolite molded catalyst obtained in the same manner as in Example 8 was steam-heat treated under the same conditions as in Example 8.

Next, the C ₅ fraction shown in Table 2 and the C ₅ fraction shown in Table 1
A raw material (unsaturated hydrocarbon / saturated hydrocarbon weight ratio 0.86) in which ₄ fractions were mixed in a ratio of 6: 4 (weight ratio) was heated to 530 ° C. and supplied to the fixed bed one-stage adiabatic reactor, The reaction product thus obtained was used as a product A rich in aromatic hydrocarbons and a carbon number of 4 and 5 using a gas-liquid separation tank and a distillation column which share a propylene refrigerant produced and used in an ethylene production process. Was separated into a product C mainly composed of non-aromatic hydrocarbon and a product D mainly composed of hydrogen and a non-aromatic hydrocarbon having 1 to 3 carbon atoms. Next, the product C was put into a tubular pyrolysis apparatus at atmospheric pressure, steam dilution ratio 0.35, COT (Co
il Outlet Temperature) is 82
Thermal decomposition was performed under the conditions of 5 ° C. and contact time of 0.32 sec. The results are shown in Table 9.

Example 10 The obtained product C containing mainly non-aromatic hydrocarbons having 4 and 5 carbon atoms was not recycled to a fixed bed one-stage adiabatic reactor,
The same operation as in Example 8 was carried out except that the obtained aromatic hydrocarbon-rich product A was subjected to a dealkylation reaction.
That is, the ZSM-5 zeolite molded catalyst obtained in the same manner as in Example 8 was steam-heat treated under the same conditions as in Example 8.

Next, C ₅ fraction shown in Table 2 and C shown in Table 1
A raw material (unsaturated hydrocarbon / saturated hydrocarbon weight ratio 0.86) in which ₄ fractions were mixed in a ratio of 6: 4 (weight ratio) was heated to 530 ° C. and supplied to the fixed bed one-stage adiabatic reactor, The reaction product thus obtained was used as a product A rich in aromatic hydrocarbons and a carbon number of 4 and 5 using a gas-liquid separation tank and a distillation column which share a propylene refrigerant produced and used in an ethylene production process. Was separated into a product C mainly composed of non-aromatic hydrocarbon and a product D mainly composed of hydrogen and a non-aromatic hydrocarbon having 1 to 3 carbon atoms. Then, the product A was subjected to a dealkylation reaction under the condition that the total aromatic conversion was 70%.
The results are shown in Table 10.

Example 11 (i) 60 parts by weight of ammonium ion type ZSM-5 crystalline aluminosilicate (Si / Al atomic ratio 46) and γ-
After kneading 15 parts by weight of alumina and 25 parts by weight of zinc nitrate,
Extrusion molding was carried out to form a diameter of 1.6 mm and a length of 4 to 6 mm. Then, after drying at 120 ° C. for 4 hours, 500
The mixture was calcined at 3 ° C. for 3 hours to obtain a ZSM-5 zeolite molded catalyst containing 10% by weight of zinc.

(Ii) Next, as the first-stage treatment, this catalyst was packed in a fixed-bed one-stage adiabatic reactor as a catalyst bed, the catalyst layer temperature was heated to 600 ° C. under nitrogen flow, and steam was added to 40
Steam-nitrogen mixed gas containing 1% by volume, pressure 1kg / cm ² ·
G (water vapor partial pressure of 0.8 kg / cm ² ), temperature of 600 ° C., weight hourly space velocity (WHSV) of water vapor of 0.08 hr ^−1, were supplied to and passed through the catalyst bed for 10 minutes. The catalyst bed was divided into seven equal parts along the flow direction of steam, and the change with time in temperature after supplying steam was measured in each catalyst bed.

Next, as the second stage treatment, supply of steam and
The flow was stopped, the steam remaining in the reactor was removed with nitrogen, and the temperature of the entire catalyst bed was kept constant at 640 ° C. Furthermore,
Steam-nitrogen mixed gas containing 40% by volume of steam heated to 640 ° C is pressure 1 kg / cm ² · G (steam partial pressure 0.8 kg
/ Cm ² ), and the temperature was kept constant at 640 ° C. for 14 minutes under the condition of weight hourly space velocity (WHSV) of steam of 0.08 hr ⁻¹ . Also at this time, the temperature change of the catalyst bed was measured in the same manner as above. The upper steam treatment was carried out using a circulation compressor, a heat exchanger, a heating furnace and piping used for regeneration by burning the catalyst.

(Iii) Next, in order to evaluate the dealumination state of this zeolite molded catalyst, a conversion reaction test of n-hexane was conducted. It is well known that the Si / Al atomic ratio of the zeolite catalyst is proportional to the initial n-hexane decomposition first-order reaction rate constant. Therefore, the catalyst was extracted from each block of the catalyst bed divided into equal parts, and the initial n-hexane decomposition first-order reaction rate constant of each catalyst was determined by the same method as in Example 1.

Table 11 shows the activity of this catalyst, and the average temperature of the uppermost catalyst and the average temperature of the lowermost catalyst during the steam treatment, together with other reaction conditions. Here, the initial n-hexane decomposition first-order reaction rate constant in Table 11 corresponds to the dealumination rate of the zeolite. Here, the uppermost catalyst means the catalyst in the uppermost layer of the catalyst bed divided into seven equal parts, and the lowermost catalyst means the catalyst in the lowermost layer portion of the catalyst bed divided into seven equal parts. . The average temperature of the uppermost catalyst and the average temperature of the lowermost catalyst are the average values of the temperatures from the upper part to the lower part.

Next, the C ₅ fraction shown in Table 2 and the C ₅ fraction shown in Table 1
A raw material (unsaturated hydrocarbon / saturated hydrocarbon weight ratio 0.86) in which ₄ fractions were mixed in a ratio of 6: 4 (weight ratio) was heated to 530 ° C. and supplied to the fixed bed one-stage adiabatic reactor. The reaction results 10 hours after the start of the reaction are shown in Table 11 together with the reaction conditions. After the above reaction, the uppermost catalyst was taken out, and the amount of coke produced on the catalyst was measured by CHN C manufactured by Yanaco Co., Ltd., Japan.
It measured using ORDER MT-5 type.

Example 12 A ZSM-5 zeolite shaped catalyst was obtained by the same method as in step (i) of Example 11. Next, step (ii) of Example 11
The zeolite shaped catalyst was steam-treated in the same manner as in Example 11 except that the second-stage treatment was not performed.
That is, the zeolite molded catalyst was packed in a fixed-bed one-stage adiabatic reactor, the catalyst bed was heated to 600 ° C. under nitrogen flow, and steam-nitrogen mixed gas containing 40% by volume of steam was supplied at a pressure of 1 kg.
/ Cm ² · G (steam partial pressure 0.8 kg / cm ² ), temperature 600
℃, weight of water vapor hourly space velocity (WHSV) 0.08hr
^It was supplied and distributed for 1 hour under the condition of ^-1 . The catalyst bed was divided into 7 equal parts, and the temperature change after steam supply in each catalyst bed was measured.

Next, the activity of the catalyst was evaluated in the same manner as in step (iii) of Example 11. Table 11 shows the activities of the catalysts at the top, middle and bottom of the reactor, and the average temperatures of the top catalyst and the bottom catalyst during steam treatment.

Next, the C ₅ fraction shown in Table 2 and the C ₅ fraction shown in Table 1
A raw material (unsaturated hydrocarbon / saturated hydrocarbon weight ratio 0.86) in which ₄ fractions were mixed in a ratio of 6: 4 (weight ratio) was heated to 530 ° C. and supplied to the fixed bed one-stage adiabatic reactor. The reaction results 10 hours after the start of the reaction are shown in Table 11 together with the reaction conditions. Further, in the same manner as in Example 11, the uppermost catalyst was extracted, and the amount of coke formed on the catalyst was measured. The measurement results are shown in Table 11 as a relative amount with respect to the amount of coke measured in Example 11. From Table 11, it can be seen that when steam treatment is carried out in two stages, coking in the upper part of the catalyst bed can be effectively suppressed.

Example 13 60 parts by weight of ammonium ion type ZSM-5 crystalline aluminosilicate (Si / Al atomic ratio 46), 15 parts by weight of γ-alumina and 25 parts by weight of zinc nitrate were kneaded, and extrusion molding was carried out. It was formed into a diameter of 1.6 mm and a length of 4 to 6 mm. Then, after drying at 120 ° C. for 4 hours, it was calcined at 500 ° C. for 3 hours to obtain a ZSM-5 zeolite molded catalyst containing 10% by weight of zinc. Next, this catalyst was packed in a fixed bed one-stage adiabatic reactor as a catalyst bed, and a steam-nitrogen mixed gas containing 40% by volume of steam was supplied at a pressure of 1 kg / cm ² · G and a temperature of 650.
The catalyst bed was supplied / circulated for 5 hours under the condition of ° C.

(I) Next, a raw material (unsaturated hydrocarbon / saturated hydrocarbon weight ratio 0: mixture of C ₅ fraction shown in Table 2 and C ₄ fraction shown in Table 1 in a ratio of 6: 4 (weight ratio) .86) to 530
Heat to 550 ° C and add 2 to the above fixed bed single-stage adiabatic reactor.
Supplied for days.

(Ii) Next, the supply of the raw material is stopped, and the carbonaceous material (coke) accumulated on the catalyst is used for about 2 days under the following conditions by using a coke combustion gas circulation circuit as shown in FIG. The catalyst was regenerated by burning off at. Oxygen concentration 0.8 to 1.2% by volume Circulation amount of combustion gas 5000 m ³ / hr (0 ° C., under atmospheric pressure) Amount of released gas outside regeneration system 7.3 to 9.2% by volume GHSV 530 hr ⁻¹ pressure 5 kg / Cm ² · G temperature 420 to 520 ° C. When regenerating the catalyst, the amount of gas 27 (fresh inert gas) (hereinafter referred to as make-up gas) shown in FIG. 7 is 3.5% by volume with respect to the combustion gas. And gas 28
The amount of (oxygen-containing inert gas) is 3.8 to 5.7% by volume.
And

Following the above catalyst regeneration (ii), the catalytic cyclization reaction of a light hydrocarbon by the same method as (i) above and the catalyst regeneration similar to (ii) above were repeatedly carried out. First
Table 12 shows the conditions and results of the catalytic cyclization reaction for the second time and the reaction conditions and results for the reaction using the catalyst for the 75th regeneration.
Shown in In addition, here, GHSV (volume hourly space velocity) means what was calculated | required by the following formula. GHSV (hr ^-1 ) = circulation amount of combustion gas (Nm ³ / hr) /
Amount of catalyst (m ³ )

Example 14 The amount of make-up gas 27 with respect to the combustion gas at the time of catalyst regeneration was 0.1% by volume, and the amount of gas released outside the regeneration system was 3.
The same operation as in Example 13 was carried out except that the amount was 9 to 5.8% by volume. Table 13 shows the conditions and results for the first catalytic cyclization reaction, and the reaction conditions and results for the reaction using the catalyst for the 75th regeneration.

Comparative Example 12 60 parts by weight of ammonium ion type ZSM-5 crystalline aluminosilicate (Si / Al atomic ratio 46), 15 parts by weight of γ-alumina and 25 parts by weight of zinc nitrate were kneaded, and extrusion molding was carried out. It was formed into a diameter of 1.6 mm and a length of 4 to 6 mm. Then, after drying at 120 ° C. for 4 hours, it was calcined at 500 ° C. for 3 hours to obtain a ZSM-5 zeolite molded catalyst containing 10% by weight of zinc. Next, this catalyst was packed in a fixed-bed single-stage adiabatic reactor as a catalyst bed, and a steam-nitrogen mixed gas containing 80% by volume of steam was supplied at a pressure of 1 kg / cm ² · G and a temperature of 550.
The catalyst bed was supplied and flowed for 1 hour under the condition of ° C.

Next, the isothermal n
When the hexane conversion reaction test was conducted in the same manner as in Example 1, the initial n-hexane decomposition first-order reaction rate constant was 3 (sec ⁻¹ ). Next, this zeolite catalyst is
A 10 mmφ quartz reaction tube (isothermal reactor) similar to that used in the hexane conversion reaction test was packed as a catalyst, and the reaction tube was externally heated in an electric furnace to raise the temperature of the entire catalyst bed to 53
It was kept constant at 8 ° C.

Next, 60 parts of n-pentane / 1-pentene was added.
The raw material (unsaturated hydrocarbon / saturated hydrocarbon weight ratio of 0.66) mixed at a ratio of / 40 (weight ratio) was heated to 538 ° C. and supplied to the above isothermal reactor, and reacted at atmospheric pressure. The results obtained 5 hours after the start of the reaction are shown in Table 13. Further, FIG. 8 shows a schematic view of a reaction apparatus including the quartz reaction tube and an electric furnace.
As shown in Table 13, although the aromatic yield after 5 hours is high,
The aromatic yield after 5 days is low, and a high aromatic yield cannot be maintained for a long period of time.

Comparative Examples 13 to 15 60 parts by weight of ammonium ion type ZSM-5 crystalline aluminosilicate (Si / Al atomic ratio 46), 15 parts by weight of γ-alumina and 25 parts by weight of zinc nitrate were kneaded, and then extrusion molding was carried out. And formed into a diameter of 1.6 mm and a length of 4 to 6 mm. Then, after drying at 120 ° C. for 4 hours, it was calcined at 500 ° C. for 3 hours to obtain a ZSM-5 zeolite molded catalyst containing 10% by weight of zinc. Next, this catalyst was packed in a fixed-bed one-stage adiabatic reactor as a catalyst bed, and a steam-nitrogen mixed gas containing 80% by volume of steam was supplied at a pressure of 1 kg / cm ² · G and a temperature of 700.
The catalyst bed was supplied / circulated for 2 hours under the condition of ° C.

Next, this zeolite molded catalyst was subjected to isothermal n
When the hexane conversion reaction test was conducted in the same manner as in Example 1, the initial n-hexane decomposition first-order reaction rate constant was 0.3 (sec ⁻¹ ). Next, the C ₅ fraction (unsaturated hydrocarbon / saturated hydrocarbon weight ratio 0.37) shown in Table 2 was replaced with 5
The mixture was heated to 30 ° C., fed to the above fixed bed one-stage adiabatic reactor, and reacted under the conditions of atmospheric pressure and WHSV = 0.8 hr ⁻¹ (Comparative Example 13). The results obtained 5 hours after the start of the reaction are shown in Table 13. Further, the same operation as in Comparative Example 13 was performed except that only saturated hydrocarbons among the C ₅ fractions shown in Table 2 were used as a raw material (Comparative Example 14). The results are shown in Table 13. Further, the same operation as in Comparative Example 13 was performed except that only unsaturated hydrocarbons among the C ₅ fractions shown in Table 2 were used as a raw material (Comparative Example 15). The results are shown in Table 13.

As shown in Table 13, the aromatic yield (22.9% by weight) of Comparative Example 13 is as shown in Comparative Examples 14 and 15.
Calculated aromatic yield (29.8
% By weight). The calculated aromatic yield is obtained as follows. (I) The amount of each component of the C ₅ fraction (component having 5 or less carbon atoms) shown in Table 2 is as follows.

[0173]

[Table 1]

(Ii) Therefore, the amount of saturated hydrocarbon is 72.
At 9% by weight, the amount of unsaturated hydrocarbons is 27.1% by weight. (iii) As shown in Table 13, the aromatic yield of Comparative Example 14 (using only saturated hydrocarbon) was 19.7% by weight.
The aromatic yield of 5 (using only unsaturated hydrocarbons) is 56.8.
weight%. (Iv) Therefore, the calculated aromatic yield is calculated by the following formula. (19.7 x 72.9 + 56.8 x 27.1) / 100
= 29.8% by weight

[0175]

[Table 2]

[0176]

[Table 3]

[0177]

[Table 4]

[0178]

[Table 5]

[0179]

[Table 6]

[0180]

[Table 7]

[0181]

[Table 8]

[0182]

[Table 9]

[0183]

[Table 10]

[0184]

[Table 11]

[0185]

[Table 12]

[0186]

[Table 13]

[0187]

[Table 14]

[0188]

[Table 15]

[0189]

[Table 16]

[0190]

[Table 17]

[0191]

[Table 18]

[0192]

According to the method of the present invention as described above, a fixed bed adiabatic reactor having a simple structure, an efficient structure, and an industrially most desirable fixed bed adiabatic reactor is used to remove light hydrocarbons containing olefins and / or paraffins. Aromatic hydrocarbons can be obtained in a high yield, the activity of the catalyst is not significantly reduced, and stable operation can be performed for a long period of time. INDUSTRIAL APPLICABILITY The method of the present invention can be widely used in the petrochemical industry and petroleum refining, and can be effectively used particularly in the production of aromatic compounds and high octane gasoline.

[Brief description of drawings]

FIG. 1 is a flow sheet showing one embodiment of the method of the present invention.

FIG. 2 is a flow sheet showing another embodiment of the method of the present invention.

FIG. 3 is a diagram showing an example of temperature distribution in the catalyst bed in the method of the present invention.

FIG. 4 is a view showing an example of a preferable uniform temperature distribution in the catalyst bed when steam-treating the zeolite-based catalyst used in the method of the present invention, together with an undesirable non-uniform temperature distribution.

FIG. 5 is a flow sheet showing one embodiment of separation of the reaction mixture in the method of the present invention.

FIG. 6 is a flow sheet showing another embodiment of separation of the reaction mixture in the method of the present invention.

FIG. 7 is a flow sheet showing one embodiment of regeneration of the zeolite-based catalyst in the method of the present invention.

FIG. 8 is a schematic diagram of an isothermal reactor used for measuring the activity of the zeolite-based catalyst used in the method of the present invention.

FIG. 9 is a flow sheet showing one embodiment of recycling of reaction products in the method of the present invention.

[Explanation of Codes] 1 fixed bed adiabatic reactor 2 fixed bed adiabatic reactor 3 raw material fluid 4 raw material fluid 5 reaction mixture fluid 6 reaction mixture fluid 7 reaction mixture fluid 8 fixed bed adiabatic reactor 9 raw material fluid 10 raw material fluid 11 raw material fluid 12 reaction mixture fluid 13 heating furnace 14 fixed bed adiabatic reactor 15 heat exchanger 16 separation means (gas-liquid separation tank and / or distillation column) 17 raw material fluid 18 raw material fluid 19 reaction mixture fluid 20 reaction mixture fluid 21 Catalyst regeneration zone 22 Circulation compressor 23 Heating furnace 24 Combustion gas 25 Exhaust combustion gas 26 Part of exhaust combustion gas 27 Inert gas 28 Inert gas containing oxygen 29 Quartz reaction tube 30 Thermometer 31 Raw material inlet 32 Raschig ring 33 Electric furnace 34 Temperature Control Thermocouple 35 Catalyst 36 Quartz Wool 37 Condenser 38 Oil Truck (Dry ice / ethanol) 39 Bag for repairing generated gas 40 Reactor 41 Purification / separation means 42 Recycled component 43 Fresh feed 44 Mixture (A) Product rich in aromatic hydrocarbons (B) Hydrogen and carbon number 1-5 Non-aromatic hydrocarbon products of paraffins, olefins and naphthenes (C) Products mainly composed of non-aromatic hydrocarbons having 4 and 5 carbon atoms (D) Hydrocarbons mainly composed of hydrogen and 1 to 3 carbon atoms Product

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location // C07B 61/00 300

Claims (33)

[Claims] 1. A method for producing an aromatic hydrocarbon from a light hydrocarbon by catalytic cyclization, wherein a light hydrocarbon raw material containing at least one selected from olefins and paraffins is treated with a substantially fresh zeolite catalyst and steam treatment. By supplying to a fixed bed adiabatic reactor having a fixed catalyst bed containing at least one zeolite catalyst selected from the group consisting of zeolite catalysts, a light hydrocarbon raw material is brought into contact with the zeolite catalyst in the reactor. When carrying out the catalytic cyclization reaction of
A method for producing an aromatic hydrocarbon, which is carried out under conditions satisfying the following requirements (1), (2), (3), and (4). (1) The zeolite-based catalyst has an initial first-order reaction rate constant of 0.2 (sec ⁻¹ ) or more as the value of the initial first-order reaction rate constant of n-hexane decomposition by the zeolite-based catalyst measured at 500 ° C. under atmospheric pressure. It has catalytic activity. (2) The temperature of the catalyst bed is 450 to 650 ° C. (3) The catalyst bed has a temperature distribution with respect to the distance from the inlet to the outlet of the catalyst bed, and the temperature distribution has at least one maximum value. (4) The temperature at the outlet of the catalyst bed is within a range of ± 40 ° C with respect to the temperature at the inlet of the catalyst bed. 2. The method according to claim 1, wherein the zeolite-based catalyst consists essentially of zeolite. 3. A zeolite-based catalyst comprising a mixture of zeolite and at least one selected from metals belonging to Group VIII, Ib, IIb and IIIb of the Periodic Table and compounds thereof. The method of claim 1, wherein 4. The method according to claim 3, wherein the zeolite-based catalyst comprises a mixture of zeolite and at least one selected from zinc and its compounds. 5. The method according to claim 4, wherein the zeolite-based catalyst comprises a mixture of zeolite, at least one selected from zinc and its compounds, and alumina. 6. The zeolite-based catalyst comprises a mixture of zeolite and a mixture of at least one selected from zinc and its compound and alumina, which has been heat-treated in steam. The method described. 7. The method according to claim 4, wherein the zeolite-based catalyst comprises a mixture of zeolite and zinc aluminate. 8. The method according to claim 4, wherein the content of at least one selected from zinc and its compounds in the zeolite-based catalyst is 5 to 25% by weight as zinc. 9. The method according to claim 1, wherein the zeolite of the zeolite-based catalyst is replaced by a metal belonging to Group VIII, Group Ib, Group IIb and Group IIIb of the periodic table. 10. The zeolite of the zeolite-based catalyst is S
The method according to claim 1, which has a zeolite skeleton having an i / Al atomic ratio of 12 or more, and contains Na at a concentration of 500 ppm by weight or less. 11. The method according to claim 1, wherein the zeolite-based catalyst comprises ZSM-5 type zeolite. 12. The zeolitic catalyst is a substantially fresh zeolitic catalyst, as claimed in any one of claims 1 to 1.
1. The method according to any one of 1. 13. The zeolite-based catalyst is a steam-treated catalyst obtained by steam-treating a substantially fresh zeolite-based catalyst.
The method described in any one of. 14. A zeolite-based catalyst, which is obtained by steam-treating a substantially fresh zeolite-based catalyst substantially consisting of zeolite, and Group VIII of the periodic table,
The method according to claim 1, characterized in that it comprises a mixture with at least one metal selected from the group Ib, the group IIb and the group IIIb and compounds thereof. 15. The steam treatment of substantially fresh zeolite-based catalyst is carried out by passing steam through a steam treatment reactor containing the substantially fresh zeolite-based catalyst in the following steps (a) and (b). 15. The method according to claim 13 or 14, characterized in that steam treatment is carried out. (A) Water vapor partial pressure 0.1 kg / cm ² or more, temperature 500 to 6
Steam at 50 ° C. is circulated in the steam treatment reactor to be brought into contact with a substantially fresh zeolite-based catalyst for 0.1 to 3 hours, and then (b) steam circulation is temporarily stopped to generate steam. After removing the residual water vapor in the treatment reactor, the water vapor partial pressure is further reduced to 0.1.
Steam of 10 to 10 kg / cm ^{2 at} a temperature of 515 to 700 ° C., the steam having a temperature higher than the flow steam temperature in the step (a), is passed through the reactor, and the step (b) is performed at least once, In each step (b), the steam flowing therein is brought into contact with the zeolite-based catalyst steam-treated in the step before the step (b). 16. The light hydrocarbon feedstock is a C ₄ cut of a product obtained from a high temperature pyrolysis apparatus for petroleum hydrocarbon materials,
Or a fraction obtained by removing butadiene or butadiene and i-butene from the C ₄ fraction; a C ₅ fraction of a product obtained from a high-temperature thermal decomposition apparatus for petroleum hydrocarbon materials, or a diene from the C ₅ fraction. Fractions removed; pyrolysis gasoline; raffinate obtained by extracting aromatic hydrocarbons from pyrolysis gasoline; F
16. CC-LPG; FCC cracked gasoline; raffinate obtained by extracting aromatic hydrocarbons from reformate; LPG from Coker; and at least one selected from straight-run naphtha. the method of. 17. The light hydrocarbon raw material comprises a saturated hydrocarbon and an unsaturated hydrocarbon, and the weight ratio of the saturated hydrocarbon to the unsaturated hydrocarbon in the light hydrocarbon raw material is 0.43 to 2.
33. The method according to any of claims 1-16, characterized in that it is 33. 18. The pressure in the fixed bed adiabatic reactor during the cyclization reaction is atmospheric pressure to 30 kg / cm ² · G and the light hydrocarbon raw material has a weight hourly space velocity (WHSV) of 0. .1
It supplies at -50 hr ^- 1.
The method described in any one of. 19. A cyclization reaction mixture containing the produced aromatic hydrocarbon is produced by using a gas-liquid separation tank and, optionally, a distillation column to produce the aromatic hydrocarbon-rich product A, hydrogen and The method according to any one of claims 1 to 18, wherein the product B containing a non-aromatic hydrocarbon having 1 to 5 carbon atoms as a main component is separated. 20. A cyclization reaction mixture containing the produced aromatic hydrocarbon is produced by using a gas-liquid separation tank and optionally a distillation column, and the product A rich in aromatic hydrocarbon and the carbon number. Products C based on 4 and 5 of non-aromatic hydrocarbons
And a product D mainly composed of hydrogen and a non-aromatic hydrocarbon having 1 to 3 carbon atoms.
8. The method according to any one of 8. 21. Propylene produced in an ethylene production process including high-temperature thermal decomposition of petroleum hydrocarbons and used as a refrigerant in the process as a refrigerant used in gas-liquid separation in the gas-liquid separation tank. 21. Method according to claim 19 or 20, characterized in that a refrigerant system consisting of ethylene is used. 22. At least a part of a product B mainly composed of hydrogen and a non-aromatic hydrocarbon having 1 to 5 carbon atoms is recycled to a fixed bed adiabatic reactor and used as a part of a light hydrocarbon feedstock. 20. The method of claim 19, wherein: 23. At least a part of a product B mainly composed of hydrogen and a non-aromatic hydrocarbon having 1 to 5 carbon atoms is supplied to a high temperature thermal decomposition apparatus for petroleum hydrocarbon material. Item 19. The method according to Item 19. 24. At least one selected from a product C mainly composed of a non-aromatic hydrocarbon having 4 and 5 carbon atoms and hydrogen and a product D mainly composed of a non-aromatic hydrocarbon having 1 to 3 carbon atoms. 21. The method according to claim 20, wherein at least a part thereof is recycled to a fixed bed adiabatic reactor and used as a part of a light hydrocarbon raw material. 25. At least one selected from a product C mainly composed of non-aromatic hydrocarbons having 4 and 5 carbon atoms and hydrogen and a product D mainly composed of non-aromatic hydrocarbons having 1 to 3 carbon atoms. 21. The method of claim 20, wherein at least a portion is fed to a high temperature pyrolysis unit for petroleum hydrocarbon materials. 26. Product A enriched in aromatic hydrocarbons,
The method according to any one of claims 19 to 25, which further comprises treating with at least one method selected from the following methods. A method of introducing the product A into a dealkylation reactor to obtain benzene; a method of introducing the product A into a distillation apparatus or an extraction apparatus or an extractive distillation apparatus to obtain benzene, toluene, and xylene; A method of treating with an isomerization reactor or an isomerization reactor; and a method of blending the product A with gasoline. 27. The light hydrocarbon raw material supply to the fixed bed adiabatic reactor is temporarily stopped, and the coke accumulated on the zeolite-based catalyst during the cyclization reaction is catalyzed by using an oxygen-containing inert gas. The method according to any one of claims 1 to 26, further comprising regenerating the zeolitic catalyst by burning off in the regeneration zone. 28. The exhaust combustion gas from the catalyst regeneration zone is recycled to the catalyst regeneration zone through a heating furnace using a circulation compressor, and the catalyst regeneration zone, the circulation compressor and the heating furnace are piped in this order. Forming a combustion gas circulation system connected by, and fresh oxygen-containing inert gas to the first inlet located between the catalyst regeneration zone outlet and the heating furnace inlet of the combustion gas circulation system, An amount of 0.05 to 50% by volume with respect to the circulation amount of the combustion gas is supplied, and exhaust combustion gas from the catalyst regeneration zone is supplied to the first inlet before reaching the heating furnace. Is released out of the system in an amount substantially equal to the amount of the above-mentioned fresh oxygen-containing inert gas,
At that time, the supply amount and the oxygen content of the fresh oxygen-containing inert gas are adjusted so that the oxygen content of the combustion gas introduced into the catalyst regeneration zone is 0.01 to 10% by volume. The method according to claim 27, wherein: 29. Further, a fresh inert gas containing no oxygen is introduced into the same inlet as the above-mentioned first inlet or between the outlet of the catalyst regeneration zone of the combustion gas circulation system and the inlet of the heating furnace. An amount of 10% by volume or less with respect to the circulation amount of the combustion gas is supplied to a second inlet, which is an inlet provided separately from, and the exhaust combustion gas from the catalyst regeneration zone is heated by the heating unit. Before reaching the furnace, it enters the catalyst regeneration zone by additionally discharging out of the system by an amount substantially equal to the amount of fresh oxygen-free inert gas supplied to the second inlet. 29. The method of claim 28, comprising suppressing an increase in the steam partial pressure of the combustion gas. 30. The method further comprises cooling the combustion gas to be compressed by the circulation compressor and heating the compressed combustion gas before reaching the furnace, with cooling and 30. The method according to claim 29, characterized in that the heating is performed by at least one heat exchanger. 31. A steam circulation system comprising a steam treatment reactor, a circulation compressor, a heating furnace and at least one heat exchanger, which are connected by a pipe, for the steam treatment of the substantially fresh zeolite-based catalyst. The method according to any one of claims 13 to 15, characterized in that 32. The method according to claim 31, wherein the steam treatment reactor is used as the adiabatic reactor. 33. The steam circulation system is used as a combustion gas circulation system for regeneration of the zeolite-based catalyst according to the method of claim 30, wherein the steam treatment reactor is used as a combustion gas circulation system. Used as it is as a catalyst regeneration reactor including the catalyst regeneration zone, or the steam treatment reactor is used instead of the catalyst regeneration reactor, and combustion gas circulation is used instead of the steam used in the steam circulation system. 33. The method according to claim 31 or 32, wherein a combustion gas used in the system is used.