JP2010064960A - Method for producing aromatic hydrocarbon - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce aromatic hydrocarbons by catalytic reaction of hydrocarbons, capable of sufficiently recovering the activity of the catalyst even if the regeneration process time is short, suppressing the deterioration of the catalyst over a long period of time, and maintaining a high reaction efficiency. A method for producing a group hydrocarbon is provided.
In a method for producing an aromatic hydrocarbon, comprising: a reaction step of producing an aromatic hydrocarbon by reacting a hydrocarbon in the presence of a catalyst; and a regeneration step of regenerating the catalyst used in the reaction step. The method for producing an aromatic hydrocarbon, characterized in that the catalyst carries a transition metal of Group 6 to Group 7 of the periodic table and a transition metal of Group 8 to Group 11 of the periodic table on a support. .
[Selection] Figure 1

Description

  The present invention relates to a process for producing aromatic hydrocarbons, which are important raw materials for chemical products. More specifically, the present invention relates to a method for effectively suppressing deterioration of a catalyst used for a reaction in a method for producing aromatic hydrocarbons by catalytic reaction of raw material methane or the like.

Conventionally, as a method of producing aromatic hydrocarbons such as benzene using lower hydrocarbons, especially methane as a raw material, so-called methane direct decomposition method in which methane is directly decomposed on a catalyst in a system without oxygen gas As the catalyst, molybdenum or rhenium usually supported on HZSM-5 zeolite can be cited (Patent Document 1).
However, in this method, coke is deposited on the catalyst due to the decomposition reaction of methane and the formation of higher-order aroma compounds, and there is a problem of a decrease in catalytic activity over time. Is essential.

  As a method for suppressing catalyst deterioration as described above, a method is known in which coke methanation reaction is accelerated by supplying hydrogen gas to the reaction system to remove coke on the catalyst. About the supply form of the hydrogen gas to the reaction system, for example, a method of adding and supplying the hydrogen gas to the raw methane gas (Patent Document 2), the raw material methane gas and the hydrogen gas are periodically and alternately supplied to the reactor, There has been proposed a method (Non-Patent Document 1) in which a reaction process by supplying raw material methane gas and a catalyst regeneration process by supplying hydrogen gas are alternately performed (Non-Patent Document 1) or a method in which both supply modes are implemented (Patent Document 3).

Among the above, the method of adding hydrogen gas to the raw material gas efficiently produces benzene because hydrogen is mixed into the reaction system, and the benzene formation reaction itself may be suppressed in consideration of the reaction equilibrium. There is a fear that you can not.
On the other hand, the raw material methane gas and the hydrogen gas are periodically and alternately supplied to the reactor, and the reaction step by the raw material methane gas supply and the catalyst regeneration step by the hydrogen gas supply are alternately performed, or in this method, In the method of performing both by combining the method of adding hydrogen gas to the raw material gas, there are problems that require a large amount of hydrogen gas, and these catalysts require a long time to recover the activity of the catalyst. However, there was a problem that the production efficiency of benzene was lowered as a result, which was much shorter than the time of the regeneration process.

Therefore, there has been a demand for a method that can shorten the time required for the regeneration step and can sufficiently recover the activity of the catalyst within the regeneration time.
JP 2004-097891 A JP 2004-269398 A WO2006 / 011568 “Catalyst Catalysts & Catalysis” (SEP.2006 Vol.48 No.6) pp. 482-484 “continuous regeneration methane dehydroaromatization reaction process with hydrogen”

  In view of the above problems, the present invention is able to sufficiently recover the activity of the catalyst even in a short regeneration time in the production of aromatic hydrocarbons by catalytic reaction of hydrocarbons, suppress catalyst deterioration over a long period of time, and It is an object of the present invention to provide a method for producing an aromatic hydrocarbon that maintains high efficiency.

As a result of intensive studies to solve the above problems, the inventors of the present invention added a transition metal from Group 6 to Group 7 of the periodic table to the support when producing aromatic hydrocarbons from hydrocarbons in the presence of a catalyst. In addition, the inventors have found that the above problem can be solved by using a catalyst carrying a transition metal of Group 8 to Group 11 of the periodic table as the second component, and have completed the present invention. That is, the gist of the present invention resides in the following [1] to [4].
[1] A method for producing an aromatic hydrocarbon, comprising: a reaction step of reacting a hydrocarbon in the presence of a catalyst to produce an aromatic hydrocarbon; and a regeneration step of regenerating the catalyst used in the reaction step. A method for producing an aromatic hydrocarbon, characterized in that the catalyst carries a transition metal of Groups 6 to 7 of the periodic table and a transition metal of Groups 8 to 11 of the periodic table on a support.
[2] The molar ratio of Group 8 to Group 11 transition metal to Group 6 to Group 7 transition metal in the catalyst is 0.001 to 1.000. The method for producing an aromatic hydrocarbon according to [1].
[3] The method for producing an aromatic hydrocarbon according to [1] or [2], wherein the catalyst regenerated in the regeneration step has a specific surface area of 150 m ² / g or more.
[4] The method for producing an aromatic hydrocarbon according to any one of [1] to [3], wherein in the regeneration step, the catalyst is regenerated with a hydrogen-containing gas.

  The catalyst according to the present invention has an advantage that the catalytic activity specific surface area after the hydrocarbon aromatization reaction can be maintained at a high value and a high catalytic activity can be maintained as compared with the conventional catalyst. Therefore, there is an advantage that the time required for the regeneration step for regenerating the catalyst used in the reaction step can be shortened when the aromatic hydrocarbon is produced by reacting the hydrocarbon with the present catalyst. Accordingly, there is an advantage that the amount of reducing gas such as hydrogen gas used in the regeneration process can be reduced. In addition, compared to the conventional method of producing aromatic hydrocarbons by reacting hydrocarbons with a catalyst, it is possible to suppress a decrease in the activity of the catalyst over a long period of time without reducing the yield of aromatic hydrocarbons. An aromatic hydrocarbon can be produced efficiently.

Hereinafter, the present invention will be described in detail. The description of the constituent requirements described below is an example (representative example) of an embodiment of the present invention, and is not specified by these contents.
The method for producing an aromatic hydrocarbon of the present invention comprises a reaction step for producing an aromatic hydrocarbon by reacting a hydrocarbon in the presence of a catalyst, and a regeneration step for regenerating the catalyst used in the reaction step. In the method for producing aromatic hydrocarbons, a regeneration step (hereinafter sometimes referred to as “regeneration”) using a reducing gas is performed as a regeneration step.

The reaction process and the regeneration process according to the present invention will be described below.
[Reaction process]
<Raw gas>
Examples of the hydrocarbon used as a raw material include lower hydrocarbon compounds having 1 to 4 carbon atoms, specifically, methane, ethane, propane, n-butane, i-butane, and unsaturated hydrocarbons corresponding thereto. Preferably, it is methane, ethane, ethylene, more preferably methane and / or ethane.

  When methane is used as the source gas, it is only necessary that methane is contained in the source gas. Usually, a source gas containing 50 vol% or more of methane is used. The raw material gas preferably contains 60 vol% or more of methane, and more preferably contains 80 vol% or more of methane. If it is such, the source gas may contain saturated and unsaturated hydrocarbons having 2 to 5 carbon atoms (for example, ethane, ethylene, propane, etc.). In addition, water, carbon monoxide, carbon dioxide, hydrogen, nitrogen and the like may be contained in the raw material gas as long as the effects of the present invention are not significantly impaired. From the viewpoint of reducing equipment costs, It is preferable to use a source gas that does not substantially contain these substances.

  Practically used hydrocarbons include natural gas (LNG, NG), LPG, methane hydrate, petrochemical or refinery off-gas, coke oven gas, coal gasification gas, asphalt gasification gas, heavy oil Residual gasification gas, petroleum coke gasification gas, reformer gas, oxo gas, biogas, biomass gasification gas, waste gasification gas and the like can be used.

(catalyst)
In the present invention, the catalyst is characterized by using a carrier carrying a transition metal belonging to Groups 6 to 7 of the periodic table and a transition metal belonging to Groups 8 to 11 of the periodic table. According to the method for producing aromatic hydrocarbons of the present invention, it is possible to efficiently produce aromatic hydrocarbons over a long period of time without reducing the activity of the catalyst and reducing the yield of aromatic hydrocarbons. it can.

The reason for this is not necessarily clear, but is estimated as follows.
In general, as one of the causes of catalyst deterioration in the production of aromatic hydrocarbons by the catalytic reaction of hydrocarbons, coke produced as a by-product in the reaction (hereinafter sometimes referred to as “by-product coke”). It can be mentioned that it deposits on the catalyst, and the by-product coke blocks the active site of the catalyst. Therefore, in order to remove the by-product coke on the catalyst or to suppress the precipitation of the by-product coke on the catalyst, the regeneration process of the catalyst is performed. Therefore, the regeneration process for a short time is not sufficient, and it is necessary to lengthen the regeneration process. On the other hand, the byproduct coke deposited on the catalyst carrying the transition metal of Group 6 to Group 7 of the periodic table and the transition metal of Group 8 to Group 11 of the periodic table has a composition different from that of the conventional byproduct coke. And is easily combusted by a reducing gas such as hydrogen, so that by-product coke can be removed even if the regeneration process time is short, and a high catalytic activity specific surface area can be maintained after the regeneration process. It is estimated that catalyst deterioration can be suppressed.

  As the catalyst metal in the present invention, a transition metal belonging to Groups 6 to 7 of the periodic table is used. Specific examples include Cr (chromium), Mn (manganese), Mo (molybdenum), Te (tellurium), W (tungsten), Re (rhenium), and the like, and preferably Mo (molybdenum) and Re (rhenium). , W (tungsten), and more preferably, Mo (molybdenum) and Re (rhenium). The reason why the activity is high when these metal-supported catalysts are used in the production of aromatic hydrocarbons is preferable. Moreover, these transition metals may be used by 1 type, or may use 2 or more types together.

Furthermore, in this invention, in addition to the said catalyst metal, the transition metal of the periodic table group 8-11 group is used as a catalyst component as a 2nd component. Specific examples include Fe (iron), Co (cobalt), Ni (nickel), and Cu (copper), and Fe (iron) is preferable from the viewpoint of catalyst stability and catalyst production cost. . These may be used alone or in combination of two or more.
The carrier used for the catalyst is not particularly limited as long as it can carry the metal. Specific examples include metal oxides such as silica, alumina, silica-alumina, zirconia, magnesia, titania, metallosilicate, silicates, phosphates, activated carbon, graphite, and the like.
Among these, metallosilicates are preferably used because the catalyst exhibits higher activity.

  Examples of the metallosilicate used in the present invention include Al, Fe, Ti, Mn, Cr, In, Ga, Mo, W, Co, V, Zn, B, P, Ge, Zr, Be, and As. Among them, those containing at least one kind of metal element selected from the above can be used, and among these, Al, P, and / or Ti are preferable because of easy availability and high activity. Al.

  As the metallosilicate used, a porous body having a large number of pores can be used. Among them, when used as a catalyst for producing an aromatic compound from a hydrocarbon, it preferably has micropores or channels having a pore diameter of 4 to 8 mm because the selectivity of the produced aromatic compound is improved. More preferably, it is a metallosilicate having micropores or channels having a pore diameter in the range of 5.5 ± 1 mm. For example, in the case of an aluminosilicate, such a metallosilicate is preferably a porous carrier zeolite composed of silica and alumina having various compositions, specifically, molecular sieve 5A (UTA), faujasite (NaY). And NaX, ZSM-5, ZSM-11, ZSM-22, ZSM-48, β, mordenite, MCM-22 and the like.

As the content ratio of silica and alumina corresponding to the content ratio of these zeolitic acid points, a commonly available porous carrier having a silica / alumina ratio of 1 to 8000 can be used. In order to obtain the selectivity, the silica / alumina ratio is preferably 10 to 100.
Further, it is a zeolite containing silica as a main component and a part of alumina as a component, and mesoporous materials such as FSM-16 and MCM-41 having cylindrical pores (channels) having mesopores (10 to 100 mm). A CVD method (Chemical Vapor Deposition) is used to supply silicon alkoxide as a gas to the carrier and form a silicon alkoxide thin film by chemical reaction on the mesoporous porous carrier surface. It is also possible to use a modified mesoporous material in which the pore diameter of the mesoporous porous carrier is adjusted to 4 to 8 mm.
When using a phosphate-based porous carrier having a structure similar to that of silicate, specifically, SAPO-5, SAPO-34, VPI-5, or the like can be used.
Moreover, as a support | carrier in this invention, the surface area of a support | carrier is 100-2000 m < ² > / g normally, Preferably, it is 200-1000 m < ² > / g In this invention, a transition metal of the periodic table group 6-7 group A metal compound can be used as a catalyst precursor when the catalyst is supported on a carrier. Examples of precursors include halides such as chloride and bromide, mineral salts such as nitrate, sulfate and phosphate, carboxylates such as carbonate, acetate and oxalate, metal carbonyl complexes and cyclopenta Examples thereof include organic metal salts such as dienyl complexes, metal acids or salts thereof. When molybdenum is used as the catalyst metal, examples of the precursor of molybdenum include metal acids such as ammonium paramolybdate, phosphomolybdic acid, and 12 silicomolybdic acid, or salts thereof.

  The amount of the transition metal of Group 6 to Group 7 in the present invention is not particularly limited, but is usually 0.001 to 50% by weight, preferably 0.01 to 40% by weight based on the total catalyst weight. %. When a plurality of catalyst metals are selected, the total supported amount of the catalyst metals is usually 0.002 to 50% by weight, preferably 0.02 to 40% by weight, based on the total catalyst weight. . The density per total catalyst weight tends to increase as the lower limit value of the supported amount increases. As the upper limit value of the supported amount decreases, the cost of the supported metal tends to be suppressed. In addition, the said support amount range shows the support amount as a metal element, when using a precursor for a catalyst material.

  As a method of supporting a transition metal of Group 6 to Group 7 on the support, (i) impregnating the support in an aqueous solution of the above-mentioned metal precursor or an organic solvent such as alcohol, and evaporating to dryness And an impregnation supporting method in which the solution is removed by distillation under reduced pressure, followed by heating, baking, and the like (ii) a method of supporting by an ion conversion method and then heat-treating in an inert gas or oxygen gas. Of these methods, the impregnation supporting method (i) is preferred from the viewpoint of simplicity of the preparation procedure.

  An example of the method (i) will be described using a more specific example. For example, when a metallosilicate is used as a carrier, an aqueous solution of paramolybdenum ammonium is impregnated and dried, and an appropriate amount of solvent is removed by drying. Thereafter, a metallosilicate catalyst supporting molybdenum can be produced by heat treatment at 250 to 800 ° C., preferably 350 to 600 ° C. in a nitrogen-containing oxygen stream or a pure oxygen stream.

  When the transition metal belonging to Group 8 to Group 11 of the periodic table is supported on a carrier, a metal compound can be used as a catalyst precursor in the same manner as the transition metal of Groups 6 to 7 of the periodic table. Examples of precursors include halides such as chloride and bromide, mineral salts such as nitrates, sulfates and phosphates, carboxylates such as carbonates, acetates and oxalates, metal carbonyl complexes and cyclopentadiates. An organic metal salt such as an aryl complex, a metal acid or a salt thereof can be exemplified.

  In the present invention, the carrying amount when carrying the transition metal of Group 8 to Group 11 on the carrier is not particularly limited, but as a value based on the total catalyst weight, usually 0.001 to 50% by weight, Preferably it is 0.001 to 20 weight%, More preferably, it is 0.01 to 5 weight%. When a catalyst in which a transition metal of Group 8 to Group 11 of the periodic table is supported on the catalyst by an impregnation method or the like is used for the reaction, if the amount supported is too large, the reaction may occur on the catalyst surface during the aromatic hydrocarbon production reaction. The reaction in which raw coke is generated is greatly accelerated, and the catalytic activity may be rapidly reduced by blocking the active sites of the catalyst.

  In the present invention, there are no particular limitations on the loading method when loading the Group 8 to Group 11 transition metal on the carrier. For example, (i) an aqueous solution of the aforementioned metal precursor or an organic solvent such as an alcohol. Impregnation support method in which the support is impregnated in the solution, and the solution is removed by evaporation to dryness or distillation under reduced pressure, followed by heating, baking, etc. (ii) After the support by the ion conversion method, inert gas or oxygen gas The method of heat-treating in the inside is mentioned. Of these methods, the impregnation supporting method (i) is preferable from the viewpoint of simplifying the procedure. The molar ratio of the Group 8 to Group 11 transition metal to the Group 6 to Group 7 transition metal is usually 0.001 or more, preferably 0.01 or more, more preferably 0.03 or more. The upper limit is usually 1 or less, preferably 0.8 or less, more preferably 0.5 or less. If this molar ratio is too small, the stability of the catalyst may decrease, and if it is too large, the activity of the catalyst may easily decrease.

The order in which the carrier carries the transition metal of Group 6 to Group 7 of the periodic table and the transition metal of Group 8 to Group 11 of the periodic table is not particularly limited. Usually, a method of impregnating a support in an aqueous solution or an alcohol or other organic solvent solution in which the respective metal precursors are dissolved together, or an aqueous solution or alcohol or other organic solvent solution in which the respective metal precursors are dissolved. Are prepared separately, and each solution is impregnated with a carrier in a two-stage process. In the case of the latter method, for example, after impregnating the support in an aqueous solution of a transition metal precursor of Group 6 to Group 7 of the periodic table or a solution such as alcohol and removing the solution by evaporation to dryness or vacuum distillation, It is impregnated and supported by heating and baking. And after obtaining the support | carrier with which the transition metal of the periodic table 6th group-the 7th group was carry | supported, this support | carrier is in solutions, such as an aqueous solution of the precursor of a periodic table 8th group-11th group transition metal, or alcohol. After removing the solution by evaporating to dryness or evaporation under reduced pressure, heating, baking, etc. are performed. Preferably, the supporting of impregnating each metal component solution is performed in two steps, and the transition metal of Group 6 to Group 7 of the periodic table and the transition metal of Group 8 to Group 11 of the periodic table are separated. It is a method of carrying in the process. More preferred is a method in which the transition metal of Group 8 to Group 11 of the periodic table is first supported on the carrier, and then the transition metal of Group 6 to Group 7 of the periodic table is supported. A method in which the carrier is loaded with the transition metals of Groups 6 to 7 of the periodic table and the transition metals of Groups 8 to 11 of the periodic table in separate steps is preferably water of the precursor of each metal component. Alternatively, it is possible to impregnate and support a metal component that is uniformly dissolved in a solution without reducing the solubility in an organic solvent. Furthermore,
After supporting the transition metal of Group 6 to Group 7 of the periodic table, the transition metal of Group 6 to Group 7 of the periodic table is supported on the support of Group 8 to Group 11 of the periodic table This method is preferable because it is considered that by supporting the metals in this order, each metal active site is supported at a preferable position and can exhibit activity without interfering with each other.

The shape of the catalyst is not particularly limited and may be any shape. For example, the shape of a powder form, a pellet form, etc. are mentioned. The size of the catalyst is not particularly limited, but when the catalyst is spherical, the particle size is usually 300 to 2000 μm, preferably 600 to 1000 μm. If this value is too large, there is a tendency that a useless volume increases in the catalyst packed bed, and if it is too small, a gradient occurs in the density of the catalyst in the catalyst layer, and the reaction gas may be supplied unevenly. . Here, the particle size is the particle size of the particles obtained by sieving the catalyst particles in a metal sieving vessel with a mesh roughness within the above range. The specific surface area of the catalyst is usually 50 m ² / g or more, preferably 100 m ² / g or more, more preferably 200 m ² / g or more, and the upper limit is usually 2000 m ² / g or less. When the specific surface area is too small, the activity when a predetermined amount of the catalyst is used may be reduced. In addition, a specific surface area can be measured based on methods, such as a BET 1 point method, for example.

In the present invention, the catalyst regeneration step is performed. The specific surface area of the catalyst after the regeneration step is 100 m ² / g or more, preferably 120 m ² / g or more, more preferably 150 m ² / g or more. The catalyst after the regeneration step is a catalyst used in the reaction step that has been regenerated at least once in the regeneration step, and the number and time of the regeneration step are not limited. The specific surface area of the catalyst after the regeneration step is usually a value measured before the catalyst that has undergone the regeneration step is used in the reaction step, and this value is obtained by taking a part of the catalyst after the reaction step. , And can be measured based on a method such as the BET one point method. As this value increases, there is a merit that the decrease in the activity of the catalyst can be suppressed. As this value decreases, the number and time of the regeneration process and the amount of regeneration gas used in the regeneration process tend to increase. .

Further, in order to shorten the induction period for generating the aromatic compound, the catalyst is used with hydrogen gas, hydrazine, metal hydride, for example, BH3, NaH, AlH3, etc. before using the catalyst in the aromatization reaction. A catalyst activation process including treatment may be performed.
<Reaction method, reaction conditions>
The reaction is usually performed in a batch-type or flow-type reaction mode, but is preferably performed in a flow-type reaction mode such as a fixed bed, a moving bed, and a fluidized bed.

The reaction temperature is usually 650 to 900 ° C.
The reaction pressure is usually 0.01 to 1 MPa (total pressure, the same applies hereinafter), preferably 0.05 to 0.7 MPa, and the feed rate (SV) of the raw material gas is usually 500 to 100,000 ml / hr · g, preferably Is 1000-20000 ml / hr · g.
When the reaction time is excessively long, the catalyst is remarkably deteriorated. When the reaction time is excessively short, the production efficiency is lowered. Therefore, the reaction time is usually 0.001 second to 10 minutes, preferably 0.001 second to 8 minutes, Preferably it is 0.001 second-4 minutes. Here, the reaction time refers to the time during which the catalyst is continuously in contact with the aforementioned raw material gas.

<Production gas>
In the present invention, a product gas containing aromatic hydrocarbons such as benzene and toluene as a main component is obtained by the reaction as described above, for example, according to the following reaction formula. In addition, the product gas obtained includes unreacted hydrocarbons such as by-produced hydrogen, ethane, ethylene, and methane in addition to the target aromatic hydrocarbon.

6CH ₄ → C ₆ H ₆ + 9H ₂
[Regeneration process]
<Reduction regeneration process>
In this reaction, by-product coke is deposited on the catalyst by the above-described aromatic hydrocarbon generation reaction and the decomposition reaction of methane, which is a raw material gas, as described below. By supplying a reducing gas such as hydrogen to the catalyst used, the coke methanation reaction as described below proceeds with respect to the catalyst co-produced coke to remove co-produced coke. This process is called a reduction regeneration process.

<Methane decomposition reaction> CH ₄ → C (coke)
<Coke Methanation> C + 2H ₂ → CH ₄
As the reducing gas used for the reduction regeneration of the catalyst used, hydrogen gas is particularly preferably used. The hydrogen concentration of the reducing gas is preferably higher, and is usually 60% by volume or more, particularly 80% by volume or more, and particularly 90% by volume or more.

Similarly to the reaction step, the reduction regeneration step is usually performed in a batch-type or flow-type reaction mode, but is preferably performed in a flow-type reaction mode such as a fixed bed, a moving bed, and a fluidized bed.
The reduction regeneration temperature is preferably performed at 650 to 900 ° C. as in the normal reaction step.
The supply pressure of the reduced regeneration gas is not particularly limited as long as it does not significantly inhibit the reduction regeneration, but is usually 0.01 to 1 MPa (total pressure, the same applies hereinafter), preferably 0.05 to 0.7 MPa. The reducing gas supply rate (SV) is usually 500 to 20000 ml / hr · g, preferably 1000 to 10,000 ml / hr · g.

If the reduction regeneration time is excessively short, a sufficient regeneration effect cannot be obtained. If the reduction regeneration time is excessively long, the reaction time is relatively shortened and the production efficiency is lowered. Minutes are preferred.
Here, the reduction regeneration time refers to the time during which the catalyst is continuously in contact with the reducing gas.

[Preferred embodiment]
When the reaction step of producing aromatic hydrocarbons by reacting hydrocarbons in the presence of a catalyst and the regeneration step of regenerating the catalyst used in the reaction step are alternately repeated, the raw material gas and the regeneration gas are combined. It is preferable that the reaction step and the regeneration step are alternately performed by periodically contacting the catalyst alternately. It should be noted that alternately performing the reaction process and the regeneration process means that even if the reaction process and the regeneration process are performed periodically, the production of aromatic hydrocarbons is temporarily stopped after the reaction process or after the regeneration process. You may perform a reproduction | regeneration process or a reaction process after progress of time.

The mode of carrying out such reactions includes:
(I) A system in which a source gas or a regeneration gas is supplied to a reactor filled with a catalyst by switching operation periodically and alternately. (Ii) A reaction zone in which the source gas flows (reaction) And a regeneration zone (regenerator) in which the regeneration gas is circulated, and a method of circulating catalyst particles can be employed. For example, a fluidized bed type reaction tower is Two towers (a reaction tower for reaction and a reaction tower for reduction regeneration) are provided, and the catalyst is preferably circulated.

A preferred embodiment of the present invention will be described below with reference to FIG.
In FIG. 1, 1 is a reaction tower (reaction tower for performing a hydrocarbon reaction), 2 is a reduction regeneration tower, and a and b are catalyst flow paths. A raw material gas is introduced into the reaction tower 1 and a product gas is taken out. Hydrogen gas, which is a reducing gas, is introduced into the reduction regeneration tower 2 and the regeneration exhaust gas is discharged.
The catalyst used for the reaction in the reaction tower 1 is extracted from the reaction tower 1, introduced into the reduction regeneration tower 2 through the flow path a, regenerated with the reducing gas, and then regenerated with the reducing gas, and then through the flow path b. Returned to By using such a catalyst circulation type reaction tower and adjusting the residence time of the catalyst in each tower, it becomes possible to carry out the reaction process and the reduction regeneration process on an appropriate time schedule.

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, unless it exceeds the summary of this invention, it is not limited to a following example.
<Preparation Example 1>
First, 0.134 g of iron (III) nitrate nonahydrate (manufactured by Wako Reagent) was dissolved in 100 ml of distilled water, and ammonia type ZSM-5 (manufactured by Zeolis, silica /
Alumina ratio = 30, with a surface area of 400m ² / g), the powder 5.0g was added, at room temperature for 1
After sufficiently stirring for a period of time, the water was evaporated with a rotary vacuum evaporator and dried at 120 ° C. overnight. This was transferred to a bakeware (diameter 15 cm, depth 6 cm) and calcined in air at 550 ° C. for 8 hours using a catalyst calcining furnace (internal volume of about 20 L) to obtain a powder (hereinafter referred to as Fe / HZSM-5). Abbreviated).

Next, molybdenum is supported on the zeolite. Ammonium paramolybdate (manufactured by Kanto Chemical Co., Ltd., 0.572 g) is dissolved in 100 ml of distilled water, 4.9 g of Fe / HZSM-5 obtained above is added, and the mixture is sufficiently stirred for 1 hour at room temperature. Was evaporated and dried at 120 ° C. overnight. This was transferred to a bakeware (diameter 15 cm, depth 6 cm), and calcined in air at 550 ° C. for 8 hours using a catalyst firing furnace (internal volume of about 20 L) to obtain a powder. Further, this powder is molded into a cylindrical body having a diameter of 2 cm and a thickness of 0.3 cm using a small manual pressure molding machine, followed by pulverization and subsequent sieving to prepare particles having a particle size of 600 to 1000 μm. Thus, a catalyst carrying 6 wt% molybdenum and 0.35 wt% iron (hereinafter abbreviated as “Fe (0.35 wt%) Mo (6 wt%) / HZMS-5”) was obtained. .

<Preparation Example 2>
A catalyst was prepared in the same manner as in Preparation Example 1 except that the weight of iron (III) nitrate nonahydrate was 0.066 g. As a result, a catalyst (hereinafter abbreviated as “Fe (0.18 wt%) Mo (6 wt%) / HZMS-5”) on which half the amount of iron was supported as compared with Preparation Example 1 was obtained.

<Preparation Example 3>
Iron and molybdenum are supported at once on zeolite. 0.134 g of iron (III) nitrate nonahydrate (manufactured by Wako Reagent) was dissolved in 100 ml of distilled water, and 0.090 g of oxalic acid (Wako Reagent) was added. After confirming that these compounds were dissolved, ammonium paramolybdate (manufactured by Kanto Chemical Co., Inc., 0.587 g) was added. The reason why oxalic acid was added to the solution is that it is considered to be effective in preventing both metal compounds from forming a composite compound and causing precipitation. After confirming the dissolution of the molybdenum salt, as a support zeolite, 5.0 g of ammonia type ZSM-5 (manufactured by Zeolis, silica / alumina ratio = 30, surface area 400 m ² / g) was added, and at room temperature for 1 hour, After thorough stirring, water was evaporated by a rotary vacuum evaporator and dried at 120 ° C. overnight. This was transferred to a bakeware (diameter 15 cm, depth 6 cm), and calcined in air at 550 ° C. for 8 hours using a catalyst firing furnace (internal volume of about 20 L) to obtain a powder.

Further, this powder is molded into a cylindrical body having a diameter of 2 cm and a thickness of 0.3 cm using a small manual pressure molding machine, followed by pulverization and subsequent sieving to prepare particles having a particle size of 600 to 1000 μm. , ZSM-5 catalyst (hereinafter referred to as “Fe (0.35 wt%) Mo (6 wt%) / HZMS-5-II”) supporting 6 wt% molybdenum and 0.35 wt% iron based on the total catalyst weight Obtained).
<Preparation Example 4>
A catalyst was prepared in the same manner as in Preparation Example 1 except that the weight of iron (III) nitrate nonahydrate was 0.268 g. As a result, a catalyst (hereinafter abbreviated as “Fe (0.7 wt%) Mo (6 wt%) / HZMS-5”) on which iron twice as much as that of Preparation Example 1 was supported was obtained.

<Preparation Example 5>
A catalyst was prepared in the same manner as in Preparation Example 1 except that the weight of iron (III) nitrate nonahydrate was 0.671 g. As a result, a catalyst (hereinafter abbreviated as “Fe (1.75 wt%) Mo (6 wt%) / HZMS-5”) on which five times the amount of iron was supported as compared with Preparation Example 1 was obtained.

<Preparation Example 6>
A catalyst was prepared in the same manner as in Preparation Example 1 except that the weight of iron (III) nitrate nonahydrate was 0.001 g. As a result, a catalyst (hereinafter abbreviated as “Fe (0.004 wt%) Mo (6 wt%) / HZMS-5”) on which 0.01 times or less of iron was supported as compared with Preparation Example 1 was obtained. .

<Preparation Example 7>
Dissolve 0.587 g of ammonium paramolybdate (manufactured by Kanto Reagent) in 100 ml of distilled water, add 5.0 g of ammonium-type ZSM-5 (silica / alumina ratio = 30, surface area 400 m ² / g) and add 1 at room temperature. After sufficiently stirring for a period of time, water was evaporated by a rotary vacuum evaporator and dried at 120 ° C. overnight. This is a bakeware (diameter 15cm, depth 6cm)
And then calcined in air at 550 ° C. for 8 hours using a catalyst firing furnace (internal volume 20 L) to obtain a powder. Further, this powder is molded into a cylindrical body having a diameter of 2 cm and a thickness of 0.3 cm using a small manual pressure molding machine, and then pulverized and subsequently sieved to prepare a powder having a particle size of 600 to 1000 μm. Thus, a ZSM-5 catalyst (hereinafter abbreviated as “Mo (6 wt%) / HZSM-5”) carrying 6% by weight of molybdenum with respect to the total catalyst weight was obtained.

<Example 1>
Fe (0.35 wt%) Mo (6 wt%) / HZMS-5 catalyst (0.324 g) prepared in Preparation Example 1 was charged into a reaction tube of a flow-type fixed bed reactor and pretreated at 700 ° C. for 2 hours. After the mixed gas of methane: hydrogen = 1: 4 was circulated and the catalyst was carbonized, the supply of the raw material gas to the reaction tube was started, and the production of benzene was started. By supplying the source gas and the regeneration gas by alternately switching them, the reaction step and the reduction regeneration step were alternately repeated under the following conditions. As for the yield of benzene after the lapse of a predetermined time, the amount of benzene produced / the amount of methane consumed was calculated as a carbon balance (%). The results are shown in Table 1.

[Reaction process]
・ Raw material gas composition: Methane: 88.6 vol%, Nitrogen: 10.1 vol%, Carbon dioxide: 1.3 vol%
・ Raw material gas flow rate: SV = 11000 ml / hr · g
・ Reaction temperature: 800 ℃
・ Reaction pressure: 0.1 MPa
・ Reaction time: 2 minutes

[Reduction regeneration process]
・ Regenerative gas composition: Hydrogen: 100 vol%
・ Regenerative gas flow rate: SV = 2500 ml / hr · g
・ Regeneration temperature: 800 ℃
・ Regeneration pressure: 0.1 MPa
-Playback time: 4 minutes <Example 2>
In Example 1, benzene was produced under the same conditions except that the regeneration time of [reduction regeneration step] was 8 minutes. The results are shown in Table 1. Further, the specific surface area of the Fe (0.35 wt%) Mo (6 wt%) / HZMS-5 catalyst was measured by the following measuring method.

[Measurement method]
Nitrogen adsorption, BET one-point method (measuring device: HM model-1201 manufactured by Mountec)
The specific surface area of the catalyst before the reaction was 291 m ² / g, the reaction step was performed for a cumulative time of 446 minutes, and the specific surface area of the catalyst after regenerating the catalyst in the regeneration step was 205 m ² / g. The cumulative time of the reaction process is the total time of the reaction process from the start of production of benzene to the end of production.

<Example 3>
In Example 2, instead of Fe (0.35 wt%) Mo (6 wt%) / HZMS-5 catalyst, Fe (0.18 wt%) Mo (6 wt%) / HZMS-5 catalyst prepared in Preparation Example 2 was used. Benzene was produced under the same conditions except that was used. In addition, it was 214 m < ² > / g when the reaction process was performed by the same method as Example 2, and the specific surface area of the catalyst after performing the accumulation | storage time for 446 minutes and reproducing | regenerating a catalyst by the reproduction | regeneration process was measured. The results are shown in Table 1.

<Example 4>
In Example 2, instead of the Fe (0.35 wt%) Mo (6 wt%) / HZMS-5 catalyst, the Fe (0.7 wt%) Mo (6 wt%) / HZMS-5 catalyst prepared in Preparation Example 4 was used. Benzene was produced under the same conditions except that it was used. The results are shown in Table 1.
<Example 5>
In Example 2, instead of Fe (0.35 wt%) Mo (6 wt%) / HZMS-5 catalyst, Fe (1.75 wt%) Mo (6 wt%) / HZMS-5 catalyst prepared in Preparation Example 5 was used. Benzene was produced under the same conditions except that was used. The results are shown in Table 1.

<Example 6>
In Example 2, instead of Fe (0.35 wt%) Mo (6 wt%) / HZMS-5 catalyst, Fe (0.004 wt%) Mo (6 wt%) / HZMS-5 catalyst prepared in Preparation Example 6 was used. Benzene was produced under the same conditions except that was used. The results are shown in Table 1.
<Example 7>
In Example 2, instead of Fe (0.35 wt%) Mo (6 wt%) / HZMS-5 catalyst, Fe (0.35 wt%) Mo (6 wt%) / HZMS-5-5 prepared in Preparation Example 3 was used. Benzene was produced under the same conditions except that the II catalyst was used. The results are shown in Table 1.

<Comparative Example 1>
In Example 2, the same conditions were used except that Mo (6 wt%) / HZSM-5 prepared in Preparation Example 7 was used instead of Fe (0.35 wt%) Mo (6 wt%) / HZMS-5 catalyst. Benzene was produced. The results are shown in Table 1.
When Example 1 and Comparative Example 1 are compared, it can be seen that the catalytic activity is rapidly reduced because the yield of benzene in Comparative Example 1 is reduced with the passage of time.

<Comparative example 2>
In Example 2, the same conditions except that the Mo (6 wt%) / HZSM-5 prepared in Preparation Example 7 was used instead of the Fe (0.35 wt%) Mo (6 wt%) / HZMS-5 catalyst. Produced benzene. The results are shown in Table 1. Further, the catalyst specific surface area of the Mo (6 wt%) / HZSM-5 catalyst was measured by the following measuring method.

[Measurement method]
Nitrogen adsorption, BET 1-point method (Measurement device HM model-1201 manufactured by Mountec)
The specific surface area of the catalyst before reaction is 287m ² / g, a specific surface area of the catalyst after reaction (cumulative time 446 min reaction step) was 125m ² / g. The cumulative reaction process time is the sum of the reaction process time from the start of benzene production to the end of production.

Thus, when Example 2 and Comparative Example 2 are compared, when the reaction step and the regeneration step are repeated to produce benzene, when the catalyst used in Example 2 reacts for the same reaction time, the same conditions are satisfied. It can be seen that a larger specific surface area can be maintained even in the regeneration process.
Thus, in the reaction using Mo (6 wt%) / HZSM-5 added with iron, the specific surface area of the catalyst is increased even when the reaction time elapses compared with the conventional Mo (6 wt%) / HZSM-5. It has been found that high conversion and benzene yield can be maintained.

It is a systematic diagram which shows the suitable embodiment of the manufacturing method of the aromatic hydrocarbon of this invention.

Explanation of symbols

1 Reaction tower 2 Reduction regeneration tower

Claims (4)

  In a method for producing an aromatic hydrocarbon, comprising a reaction step of producing an aromatic hydrocarbon by reacting a hydrocarbon in the presence of a catalyst, and a regeneration step of regenerating the catalyst used in the reaction step, A process for producing an aromatic hydrocarbon, characterized in that a carrier carries a transition metal of Groups 6 to 7 of the periodic table and a transition metal of Groups 8 to 11 of the periodic table.   The molar ratio of the transition metal of Group 8 to Group 11 of the periodic table to that of Group 6 to Group 7 of the periodic table in the catalyst is 0.001 to 1.000. A process for producing an aromatic hydrocarbon according to 1. The method for producing an aromatic hydrocarbon according to claim 1 or 2, wherein a specific surface area of the catalyst regenerated in the regeneration step is 150 m ² / g or more.   The method for producing an aromatic hydrocarbon according to any one of claims 1 to 3, wherein in the regeneration step, the catalyst is regenerated with a hydrogen-containing gas.

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