JP2009221033A - Material composition for hydrogen formation and method for producing hydrogen - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic compound material for hydrogen formation which suppresses activity deterioration in a dehydrogenation catalyst in hydrogen production by a dehydrogenation reaction of an organic compound having a cyclohexane ring and can enhance conversion rate. <P>SOLUTION: A composition containing ≥50 mol% of an organic compound having a cyclohexane ring and also containing ≥0.1 mol% of an oxygen-containing compound is used. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a raw material composition for generating hydrogen. Specifically, the present invention relates to a raw material composition for hydrogen generation that can suppress the deterioration of the activity of a dehydrogenation catalyst in hydrogen production by dehydrogenation of an organic compound having a cyclohexane ring and can improve the conversion rate. The present invention also relates to a method for producing hydrogen using such a raw material composition, and further relates to a miniaturizable hydrogen production system that separates hydrogen by membrane separation.

  Hydrogen is widely used in various industrial fields including the oil refining and chemical industries. In particular, hydrogen energy has been attracting attention as a future energy, and research is focused on fuel cells. However, hydrogen gas has a large volume per calorie and also requires a large amount of energy for liquefaction. The storage and transportation system is an important issue. In addition, it is necessary to develop a new infrastructure for supplying hydrogen (see Non-Patent Document 1).

Liquid hydrocarbons, on the other hand, have the advantage of being easy to handle and having a higher energy density than hydrogen gas, and also have the advantage of being able to use existing infrastructure. The method of producing hydrogen from methane is important.
Production of hydrogen is widely carried out by known techniques such as steam reforming of methane and light paraffin, autothermal reforming, and partial oxidation, but these reactions require high temperatures. Furthermore, in the case where on-site power generation by a fuel cell, particularly a polymer electrolyte fuel cell, is intended to produce CO as a by-product, a shift reactor and carbon monoxide by CO selective oxidation or methanation are provided in the subsequent stage. A remover is required, which is a very complex process. In addition, when an automobile hydrogen station is targeted, high purity hydrogen must be obtained using PSA (pressure swing adsorption). The same applies to the methanol reforming system.

  On the other hand, a reaction using a liquid organic compound having a cyclohexane ring as a raw material and dehydrogenating the cyclohexane ring to an aromatic ring is simple and has no CO by-product, so the production and purification process is also simple. is there. Furthermore, the reaction proceeds easily in the presence of a dehydrogenation catalyst, and the product is an organic compound having a gaseous hydrogen and a liquid aromatic ring. (See Non-Patent Document 2). In addition, since the by-product CO treatment step (for example, CO shift reaction) is unnecessary, the start-up time until hydrogen generation can be remarkably shortened. For this reason, in applications where the miniaturization of the hydrogen generation system and the shortening of the start-up time are strongly demanded, for example, on-board hydrogen generation type fuel cell automobiles that generate hydrogen on the vehicle and generate power with the fuel cell and run by the motor, Compared to the above-mentioned hydrocarbon steam reforming method and methanol reforming method, it is particularly suitable.

However, in this dehydrogenation reaction, deterioration of the catalyst activity is a problem, and it is said that the main factor is carbon deposition. In order to suppress the deterioration of activity, it is necessary to suppress the progress of the cleavage reaction of the aromatic ring, which is the initiation reaction of carbon deposition. For example, it is considered to exhibit high activity in the dehydrogenation reaction of hydrocarbons having a cyclohexane ring. In the platinum / alumina system, studies have been made to suppress the decomposition reaction at the acid sites on the alumina support by adding alkali metal potassium, and the result of improved durability has been obtained (see Non-Patent Document 3). . However, hydrogen must be supplied at the time of the dehydrogenation reaction, and it cannot be said that there is a sufficient effect for suppressing deterioration in the absence of hydrogen.
For example, in the case of application to the above-mentioned on-board hydrogen generating fuel cell vehicle, supplying hydrogen during the dehydrogenation reaction requires a separate hydrogen supply system, which is extremely disadvantageous in terms of downsizing the hydrogen generating system. . For this reason, there has been a strong demand for a method of suppressing the deterioration of the catalyst activity in the dehydrogenation reaction without supplying hydrogen.
Nori Kobayashi, “Quarterly Energy Comprehensive Engineering”, 2003, Vol. 25, No. 4, p. 73-87 Masaru Ichikawa, “Industrial Materials”, 2003, Vol. 51, No. 4, p. 62-69 Yoshiaki Okada et al., “Hydrogen Energy System”, 2006, Vol. 31, No. 2, p. 3-13

  The object of the present invention is to improve the raw material itself in order to suppress the deterioration of the activity of the dehydrogenation catalyst in the hydrogen production by the dehydrogenation reaction of the organic compound having a cyclohexane ring, and to improve the conversion rate. To provide a raw material composition that can efficiently and stably generate hydrogen, and to provide a method for producing hydrogen using the raw material composition.

  As a result of intensive studies to solve the above problems, the present inventors can suppress the deterioration of the activity of the dehydrogenation catalyst and improve the conversion rate by blending an oxygen-containing compound with an organic compound having a cyclohexane ring. And the present invention has been completed.

  That is, the present invention provides a hydrogen-producing raw material composition for producing hydrogen by a dehydrogenation reaction of a cyclohexane ring, comprising 50 mol% or more of an organic compound having a cyclohexane ring and 0.1 mol% or more of an oxygen-containing compound. About.

  The present invention also relates to the above-mentioned raw material composition for hydrogen generation, wherein the organic compound having a cyclohexane ring is at least one organic compound selected from cyclohexane, tetralin, decalin, and alkyl-substituted products thereof. .

  The present invention also relates to the above-described raw material composition for hydrogen generation, wherein the oxygen-containing compound is at least one oxygen-containing compound selected from alcohol, ether and water.

  The present invention also relates to the above-described raw material composition for hydrogen generation, wherein the alcohol is an alcohol having 2 or more carbon atoms.

  In addition, the present invention relates to the above-described raw material composition for hydrogen generation, wherein the ether alkyl group is an alkyl group having 2 or more carbon atoms.

  Further, the present invention is characterized in that in the presence of a dehydrogenation catalyst, the above-described hydrogen-producing raw material composition is circulated to generate hydrogen by dehydrogenating a cyclohexane ring and to obtain a dehydrogenation reaction product. The present invention relates to a method for producing hydrogen.

  In addition, the present invention burns at least one selected from the hydrogen and dehydrogenation reaction products obtained by the above-described method and the raw material composition for hydrogen generation before the dehydrogenation reaction, and dehydrates using the heat of combustion. The present invention relates to a method for producing hydrogen, characterized by performing an elementary reaction.

  Furthermore, the present invention relates to a hydrogen production system characterized in that hydrogen obtained by the above method and a dehydrogenation reaction product are separated by membrane separation.

  By applying the hydrogen generating raw material composition according to the present invention to the dehydrogenation reaction, it is possible to provide a method for producing hydrogen in which deterioration of the catalyst is suppressed and the conversion rate is further improved. Furthermore, an efficient hydrogen production system with excellent durability can be provided.

Hereinafter, the present invention will be described in detail.
As the raw material composition for hydrogen generation of the present invention, an organic compound having a cyclohexane ring as a main component is used. In the present invention, the cyclohexane ring refers to a saturated 6-membered ring that can be dehydrogenated, and an aromatic ring is generated by a dehydrogenation reaction, and the generated aromatic ring is not limited to a benzene ring, but two rings, three rings And those that become polycyclic aromatic rings (condensed rings).
The organic compound having a cyclohexane ring used in the present invention is not particularly limited, but a monocyclic or bicyclic compound having a cyclohexane ring is preferable. Moreover, although you may have a substituent, what does not have a bad influence on dehydrogenation reaction is preferable. The substituent is preferably an alkyl group, and the alkyl group is preferably an alkyl group having 1 to 4 carbon atoms.

  Specific examples of the organic compound having a cyclohexane ring used in the present invention include cyclohexane, methylcyclohexane, decalin, methyldecalin, tetralin, and methyltetralin. Among these, cyclohexane, methylcyclohexane, decalin, and methyldecalin are preferable, and methylcyclohexane is particularly preferable. In addition, the organic compound having a cyclohexane ring may be a mixture of a plurality of organic compounds, and appropriately contains other compounds, for example, hydrocarbons having no cyclohexane ring, as long as the dehydrogenation reaction is not hindered. Also good.

  The content ratio of the organic compound having a cyclohexane ring in the raw material composition for hydrogen generation of the present invention needs to be 50 mol% or more based on the total amount of the raw material composition, preferably 60 mol% or more, more preferably It is 70 mol% or more. When the content ratio of the organic compound having a cyclohexane ring is less than 50 mol%, the amount of hydrogen generation is decreased, which is not preferable. On the other hand, the upper limit is 99.9 mol% or less, preferably 99 mol% or less.

Examples of the oxygen-containing compound to be blended in the raw material composition for hydrogen generation of the present invention include an oxygen-containing organic compound and water.
In the case of an oxygen-containing organic compound, those having 2 or more carbon atoms are preferred. Moreover, although it can be used up to about 16 carbon atoms of the light oil class, a compound that becomes significantly heavier than hydrocarbons containing a cyclohexane ring may cause a problem in use. The following are preferred. As the oxygen-containing organic compound, alcohol and ether are particularly preferable.
The raw material composition for hydrogen generation of the present invention may contain two or more different oxygenated compounds. When two or more oxygen-containing compounds are used, two or more different oxygen-containing compounds may be added individually to the organic compound having a cyclohexane ring, or a mixture of oxygen-containing compounds may be added.

  As alcohol used as an oxygen-containing organic compound, a C2-C6 alcohol is preferable. Specific examples include ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, isobutyl alcohol, t-butyl alcohol, ethylene glycol, and glycerin. Of these, ethanol, 2-propanol, 1-butanol, 2-butanol, isobutyl alcohol, and t-butyl alcohol are more preferable.

  The ether used as the oxygen-containing organic compound is preferably an ether having 2 to 8 carbon atoms. Specifically, dimethyl ether, ethyl methyl ether, diethyl ether, methyl propyl ether, methyl isopropyl ether, ethyl propyl ether, ethyl isopropyl ether, diisopropyl ether, methyl butyl ether, methyl isobutyl ether, methyl t-butyl ether, ethyl butyl ether, ethyl isobutyl Examples include ether and ethyl t-butyl ether. Of these, ethyl isopropyl ether and ethyl t-butyl ether are more preferable.

  The content ratio of the oxygen-containing compound in the raw material composition for hydrogen generation of the present invention needs to be 0.1 mol% or more based on the total amount of the raw material composition. Although the effect of suppressing deterioration of the dehydrogenation catalyst increases as the content ratio of the oxygen-containing compound increases, the content ratio of the organic compound containing the cyclohexane ring relatively decreases, so that the amount of hydrogen generation decreases. Therefore, an appropriate range exists. The content ratio of the oxygen-containing compound is preferably 0.5 mol% or more, and more preferably 1 mol% or more. Moreover, 40 mol% or less is preferable and 30 mol% or less is more preferable.

In the present invention, in the presence of a dehydrogenation catalyst, the above-described raw material composition for hydrogen generation is circulated to generate hydrogen by dehydrogenating the cyclohexane ring, and a dehydrogenation reaction product is obtained.
The main component of catalytic activity in the dehydrogenation catalyst is a component having dehydrogenation activity, and can be arbitrarily selected. Preferably, Group 7A, Group 8, Group 1B elements of the periodic table, specifically iron, cobalt, nickel, copper, ruthenium, rhodium, palladium, silver, rhenium, osmium, iridium, platinum, gold, etc. Is mentioned. Among these, nickel, palladium, platinum, and rhenium are preferable. Two or more of these elements may be combined. In this specification, the notation of the periodic table is based on the IUPAC 1987 edition.

These catalytically active main components are generally used by being supported on a carrier. Although the method of making it support | carrier is arbitrary, the impregnation method is mentioned preferably. Specific examples include the Pore-filling method, the Incipient Wetness method, and the evaporation to dryness method.
The compound used in the impregnation method is preferably a water-soluble salt, and is preferably impregnated as an aqueous solution. Preferred examples of the water-soluble compound include chlorides, nitrates, carbonates, acetates, and ammonium salts. In the case of a noble metal, it is also preferable to use a colloidal solution of metal, for example, a colloidal solution of platinum is preferably used. In this case, the particle diameter of the platinum colloid particles is preferably 4 nm or less.

  As the carrier, metal oxides and composite metal oxides having high mechanical strength, thermal stability, and large surface area are preferable, and specific examples include alumina, silica, titania, zirconia, and the like. preferable. Further, the shape may be any shape such as a granular shape that is usually a molded product, a powder shape, a plate shape, or a fin shape as described later.

  An additive may coexist if necessary in the dehydrogenation catalyst. Preferred additives include tin and basic substances. Tin suppresses the aggregation of active metals. The coexistence of the basic substance suppresses side reactions such as decomposition caused by acidity, and suppresses deterioration of the catalyst due to carbonaceous deposition. The type of basic substance is arbitrary, but compounds of Group 1A elements and Group 2A elements are preferable, and specifically, lithium, sodium, potassium, rubidium, cesium, beryllium, magnesium, calcium, strontium, barium, etc. Compounds. These compounds are preferably water-soluble substances. More preferred are chlorides, sulfates, nitrates, carbonates, acetates and ammonium salts. The content of the basic substance is preferably in the range of 0.1 to 100 by weight ratio with respect to the catalytically active main component. A preparation method for incorporating these basic substances into the catalyst is optional, but an impregnation method is preferred. Specific examples include the Pore-filling method, the Incipient Wetness method, and the evaporation to dryness method.

The cyclohexane ring dehydrogenation reaction is generally a reversible reaction and an endothermic reaction. In terms of chemical equilibrium, conditions of high temperature and low pressure are advantageous, but the reaction conditions are appropriately selected according to various requirements such as the type of reaction raw material, the conditions on the system of the hydrogen generation system, the heat resistance of the material, and the amount of heat release. it can. The lower limit of the reaction pressure is preferably 0.1 MPa or more, and more preferably 0.11 MPa or more. As an upper limit, Preferably it is 2.0 MPa or less, More preferably, it is 1.0 MPa or less. In the present specification, unless otherwise specified, the pressure is expressed as an absolute pressure. The reaction temperature is preferably a high temperature in terms of chemical equilibrium, but a low temperature is preferable in terms of energy efficiency. The reaction temperature is preferably 200 ° C. or higher, more preferably 270 ° C. or higher, most preferably 320 ° C. or higher as the lower limit, and the upper limit is preferably 400 ° C. or lower, more preferably 380 ° C. or lower, most preferably 360 ° C. or lower. Although it is disadvantageous in terms of chemical equilibrium, hydrogen can be added to the raw material for the purpose of preventing the deactivation of the catalyst or for the reason of operating the apparatus. In the present invention, it is also an important feature that the deterioration of the catalyst can be suppressed without adding hydrogen.
A preferable range of LHSV (liquid hourly space velocity) depends on the activity of the catalyst, but is usually 0.2 hr ⁻¹ or more and 40 hr ⁻¹ or less.

  Although there is no restriction | limiting in particular about a hydrogen production system, Since the system which can be reduced in size meets the objective of this invention, it is preferable. As an example of this, by using a membrane reactor having a so-called combustion gas heater, a dehydrogenation catalyst and a hydrogen separation membrane are provided, and hydrogen is separated simultaneously during the dehydrogenation reaction to obtain high-purity hydrogen, and a dehydrogenated product And it can be set as the system which can supply the heat required for a dehydrogenation reaction by burning non-permeated hydrogen. For example, a raw material composition is circulated from one of the flow-type reaction tubes, a substrate (an organic compound having a cyclohexane ring) is dehydrogenated by a dehydrogenation catalyst present inside, hydrogen and a reaction product are generated, and hydrogen generated At the same time, the membrane is separated in situ by a hydrogen separation membrane, and hydrogen is selectively permeated to obtain high-purity hydrogen. Hydrogen is quickly separated, and heat is easily supplied to the dehydrogenation reaction part, which is an endothermic reaction, by an appropriate heating source such as catalytic combustion and / or combustion gas, and the dehydrogenation reaction proceeds.

As the hydrogen separation membrane, a metal membrane or a porous inorganic membrane capable of selectively separating hydrogen from a mixed gas of hydrocarbon and hydrogen is preferably used.
In the case of a metal membrane, it is a hydrogen separation membrane in which a metal thin film is formed on the inner surface or outer surface of a tubular porous metal support having pores or a porous ceramic support having pores. A metal film containing 100 to 10% by mass of Pd, or a metal film containing 80 to 10% by mass of at least one metal selected from Ag, Cu, V, Nb, and Ta is preferable.
Although any method can be selected as the method for forming the metal thin film on the support for the separation membrane, specific examples include electroless plating, vapor deposition, and rolling.

  In the case of a porous inorganic membrane, a hydrogen separation membrane in which a ceramic thin film having a controlled pore size is formed on the inner or outer surface of a porous porous ceramic support having pores is preferable. Since the porous inorganic membrane is selectively separated by molecular sieve action, the pore diameter of the thin film portion is preferably 0.3 nm or more and 0.7 nm or less, and more preferably 0.3 nm or more and 0.5 nm or less. A known ceramic material can be used as the material of the ceramic film, but silica, alumina, titania, glass, silicon carbide, and silicon nitride are preferable.

The thermally conductive support material constituting the hydrogen production system can be a material having a thermal conductivity at 300K of 10 W / m · K or more. Specifically, metals are preferable, and those having a film such as an oxide on the surface are included. Specifically, any metal and alloy usually used as a heat conductive material can be used, but aluminum or a metal or alloy having aluminum on the surface is particularly preferable.
Since it is a metal, its thermal conductivity is high, and there is an effect that the heat supply is fast and the reaction efficiency is improved. That is, since the dehydrogenation reaction is an endothermic reaction, a metal tube is used for the reaction portion, and heat is supplied by heating by an appropriate heating means, thereby giving heat to the dehydrogenation reaction in the gap between the catalyst and the hydrogen separation membrane. This facilitates application of heat to the dehydrogenation reaction.

Any method can be employed to hold the catalyst on the dehydrogenation reaction surface. For example, a method in which a catalyst carrier is first held on the dehydrogenation reaction surface and then a catalytically active component is supported on the held carrier to hold the dehydrogenation catalyst on the dehydrogenation reaction surface. Preferable examples include a method in which the dehydrogenation reaction surface is pretreated so as to have a high surface area, and then the catalyst carrier and the catalyst active component are supported. A known method can be adopted as a treatment method for increasing the surface area of the dehydrogenation reaction surface. For example, as described in JP-A No. 2002-119856, there is a method of increasing the surface area based on anodizing treatment.
The outer surface having a high surface area is preferably formed with a metal oxide layer having a stable and high surface area such as alumina for supporting the catalyst. For this purpose, for example, an alumina hydrate sol can be applied to a dehydrogenation reaction surface treated with a high surface area, dried, and then fired to form a metal oxide layer as a carrier.

Since the dehydrogenation reaction according to the present invention is an endothermic reaction, it is preferable that the heat supply source and the catalyst are in direct contact in order to efficiently supply the dehydrogenation reaction heat. For this reason, it is preferable to increase the area in contact with the raw material composition by making the shape of the carrier plate-like, tubular, or fin-like in direct contact with the dehydrogenation reaction surface. Any shape can be adopted as long as it is possible to increase the area in direct contact with the heating source and in contact with the raw material composition.
For example, the fin type may have a structure in which a plurality of fin-like protrusions extending in the axial direction and extending outward are provided on the dehydrogenation reaction surface. The catalyst is directly held on the fin surface. Preferably, as described above, a metal oxide layer is formed on the surface, and a catalytically active component is supported on the oxide layer as a support. Since such a fin type has a large contact area with the raw material composition, heating is easy and it is preferable. Further, when a heating source is disposed outside the tube, it is preferable because it can directly contact the heating source.

  The product of dehydrogenation in the case of using an organic compound having a cyclohexane ring as a raw material is hydrogen and an unsaturated hydrocarbon, and the unsaturated hydrocarbon is mainly an aromatic hydrocarbon. These can be recovered and hydrogenated to return to the starting hydrocarbon. Alternatively, it can also be used as a heat source fuel necessary for the dehydrogenation reaction, if necessary. In addition, since aromatic hydrocarbons generally have a high octane number, substances having a suitable boiling point can also be used as a gasoline base material. Alternatively, it can be used as a chemical product. From such a viewpoint, a method of dehydrogenating a hydrocarbon having a cyclohexane ring as a raw material and obtaining an aromatic hydrocarbon in addition to hydrogen as a dehydrogenation product is a preferable method.

Although the hydrogen produced by the dehydrogenation reaction is in a state where it is mixed with a reaction product such as an aromatic hydrocarbon, the hydrogen can be immediately separated in situ by a hydrogen separation membrane.
Here, the permeation side pressure of the hydrogen separation membrane in the membrane separation reactor is preferably 0.2 MPa or less, and more preferably 0.12 MPa or less. Further, it is preferable to supply an inert gas to the permeation side of the hydrogen separation membrane for the purpose of reducing the permeation side hydrogen partial pressure. The permeate side hydrogen partial pressure is preferably 0.12 MPa or less, and more preferably 0.05 MPa or less. Most preferably, it is 0.01 MPa or less.

  Continuous hydrogen production by removing hydrogen from the permeate side (permeate side) and unreacted raw material composition and dehydrogenated product from the non-permeate side (before permeation side) Can do. A dehydrogenated product such as toluene can be extracted together with hydrogen from the non-permeate side as appropriate. The unreacted raw material composition and the like on the non-permeate side can be burned to form a heating medium for dehydrogenation reaction.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to the range of these Examples.

Example 1
A spherical commercial catalyst having an average diameter of 1.5 mm, in which 0.3% by mass of platinum was supported on a γ-alumina carrier, was designated as Catalyst A. 3 ml of catalyst A was filled in a stainless steel reaction tube having an inner diameter of 8 mm and attached to a fixed bed flow system reactor. As a pretreatment, hydrogen was added at 50 ml / min. After flowing at 300 ° C. for 1 hour, the substrate was purged with nitrogen. A raw material obtained by adding 5 mol% of ethanol to methylcyclohexane (MCH) based on the total amount of the composition was used in the experiment. Stop supplying nitrogen and supply a predetermined amount of raw material from the inlet of the reaction tube using a microfeeder without flowing gas, and the reaction temperature (the temperature distribution in the catalyst layer is generated by the endothermic reaction, so the catalyst layer outlet The experiment was started under conditions of 330 ° C. (reaction temperature), reaction pressure of 0.1 MPa (atmospheric pressure), and LHSV = 5 h ⁻¹ , and the product liquid obtained from the reaction tube outlet was analyzed with a gas chromatograph. The change with time of the conversion was measured. The experiment was carried out over several days in a way that was stopped for a few hours a day, then stopped and restarted. When stopping, the supply of raw materials was stopped and the reaction temperature was immediately lowered. At the time of restarting, the reaction temperature started to increase and at the same time, the feed of raw materials was started. There was no hydrogen reduction or nitrogen purge between shutdown and restart. Table 1 shows the MCH conversion rate at an accumulated oil flow rate of 0.05 L and the MCH conversion rate at an accumulated oil flow rate of 0.25 L.

(Example 2)
An experiment was conducted in the same manner as in Example 1 except that a raw material in which 5 mol% of 2-propanol was added to methylcyclohexane was used instead of the raw material in which 5 mol% of ethanol was added to methylcyclohexane. Table 1 shows the MCH conversion rate at an accumulated oil flow rate of 0.05 L and the MCH conversion rate at an accumulated oil flow rate of 0.25 L.

(Example 3)
An experiment was conducted in the same manner as in Example 1 except that a raw material in which 1 mol of 1-butanol was added to methylcyclohexane was used instead of the raw material in which 5 mol% of ethanol was added to methylcyclohexane. Table 1 shows the MCH conversion rate at an accumulated oil flow rate of 0.05 L and the MCH conversion rate at an accumulated oil flow rate of 0.25 L.

Example 4
An experiment was conducted in the same manner as in Example 1 except that a raw material in which 5 mol% of isobutyl alcohol was added to methylcyclohexane was used instead of the raw material in which 5 mol% of ethanol was added to methylcyclohexane. Table 1 shows the MCH conversion rate at an accumulated oil flow rate of 0.05 L and the MCH conversion rate at an accumulated oil flow rate of 0.25 L.

(Example 5)
An experiment was conducted in the same manner as in Example 1 except that a raw material in which 5 mol% of t-butyl alcohol was added to methylcyclohexane was used instead of the raw material in which 5 mol% of ethanol was added to methylcyclohexane. Table 1 shows the MCH conversion rate at an accumulated oil flow rate of 0.05 L and the MCH conversion rate at an accumulated oil flow rate of 0.25 L.

(Example 6)
An experiment was conducted in the same manner as in Example 1 except that a raw material in which 1 mol% of 2-propanol was added to methylcyclohexane was used instead of the raw material in which 5 mol% of ethanol was added to methylcyclohexane. Table 1 shows the MCH conversion rate at an accumulated oil flow rate of 0.05 L and the MCH conversion rate at an accumulated oil flow rate of 0.25 L.

(Example 7)
An experiment was conducted in the same manner as in Example 1 except that a raw material in which 15 mol% of 2-propanol was added to methylcyclohexane was used instead of the raw material in which 5 mol% of ethanol was added to methylcyclohexane. Table 1 shows the MCH conversion rate at an accumulated oil flow rate of 0.05 L and the MCH conversion rate at an accumulated oil flow rate of 0.25 L.

(Example 8)
An experiment was conducted in the same manner as in Example 1 except that a raw material in which 20 mol% of 2-propanol was added to methylcyclohexane was used instead of the raw material in which 5 mol% of ethanol was added to methylcyclohexane. Table 1 shows the MCH conversion rate at an accumulated oil flow rate of 0.05 L and the MCH conversion rate at an accumulated oil flow rate of 0.25 L.

Example 9
An experiment was conducted in the same manner as in Example 1 except that a raw material in which 5 mol% of isopropyl ether was added to methylcyclohexane was used instead of the raw material in which 5 mol% of ethanol was added to methylcyclohexane. Table 1 shows the MCH conversion rate at an accumulated oil flow rate of 0.05 L and the MCH conversion rate at an accumulated oil flow rate of 0.25 L.

(Example 10)
An experiment was conducted in the same manner as in Example 1 except that a raw material in which 5 mol% of ethyl t-butyl ether was added to methylcyclohexane was used instead of the raw material in which 5 mol% of ethanol was added to methylcyclohexane. Table 1 shows the MCH conversion rate at an accumulated oil flow rate of 0.05 L and the MCH conversion rate at an accumulated oil flow rate of 0.25 L.

(Example 11)
Example 1 except that methylcyclohexane and water were supplied from another microfeeder to the reaction tube inlet instead of using a raw material obtained by adding 5 mol% of ethanol to methylcyclohexane. The experiment was conducted in the same manner as above. Table 1 shows the MCH conversion rate at an accumulated oil flow rate of 0.05 L and the MCH conversion rate at an accumulated oil flow rate of 0.25 L.

Example 12
An experiment was conducted in the same manner as in Example 1 except that a raw material in which 5 mol% of methanol was added to methylcyclohexane was used instead of the raw material in which 5 mol% of ethanol was added to methylcyclohexane. Table 1 shows the MCH conversion rate at an accumulated oil flow rate of 0.05 L and the MCH conversion rate at an accumulated oil flow rate of 0.25 L.

(Comparative Example 1)
An experiment was conducted in the same manner as in Example 1 except that methylcyclohexane not containing an oxygen-containing compound was used as a raw material instead of the raw material obtained by adding 5 mol% of ethanol to methylcyclohexane. Table 1 shows the MCH conversion rate at an accumulated oil flow rate of 0.05 L and the MCH conversion rate at an accumulated oil flow rate of 0.25 L.

(Comparative Example 2)
Fig. 1 shows a prototype membrane separation reactor. It has a Pd-based hydrogen separation membrane having a hydrogen permeation portion length of 12 cm and an outer diameter of 10 mm in the center, and a heat exchanger type catalyst (catalyst portion length of 12 cm, catalyst volume of 24 ml) around the periphery. It has a configuration. As shown in FIG. 2, a heater having a catalytic combustion section was installed on the outer periphery of the membrane separation reactor, and a hydrogen generation system was prototyped. The dehydrogenation reaction section is heated by burning toluene.
Using this hydrogen generation system, a hydrogen production test from methylcyclohexane was conducted. While controlling the reaction temperature by adjusting the amount of toluene in the fuel, the experiment was conducted under the conditions of LHSV = 7.5 h ⁻¹ , reaction temperature (the temperature at the outlet of the catalyst section was the reaction temperature) 330 ° C., and the reaction pressure was 0.5 MPa. And a steady state was reached in about 2 hours from the start of the reaction. The methylcyclohexane conversion at this time was 76%.

(Example 13)
The experiment was performed in the same manner as in Comparative Example 2 except that the hydrogen generation system shown in Comparative Example 2 was used with a raw material obtained by adding 5 mol% of ethanol to methylcyclohexane. The methylcyclohexane conversion at this time was 85%.

3 is a schematic view of a membrane separation reactor experimentally manufactured in Comparative Example 2. FIG. 6 is a schematic diagram of a hydrogen generation system prototyped in Comparative Example 2. FIG.

Claims (8)

  A raw material composition for generating hydrogen, which contains 50 mol% or more of an organic compound having a cyclohexane ring and 0.1 mol% or more of an oxygen-containing compound, and generates hydrogen by a dehydrogenation reaction of the cyclohexane ring.   2. The raw material composition for hydrogen generation according to claim 1, wherein the organic compound having a cyclohexane ring is at least one organic compound selected from cyclohexane, tetralin, decalin, and alkyl-substituted products thereof.   The hydrogen-containing raw material composition according to claim 1 or 2, wherein the oxygen-containing compound is at least one oxygen-containing compound selected from alcohol, ether and water.   4. The raw material composition for hydrogen generation according to claim 3, wherein the alcohol is an alcohol having 2 or more carbon atoms.   4. The raw material composition for hydrogen generation according to claim 3, wherein the ether alkyl group is an alkyl group having 2 or more carbon atoms.   In the presence of a dehydrogenation catalyst, the hydrogen-producing raw material composition according to any one of claims 1 to 5 is circulated to generate hydrogen by dehydrogenating a cyclohexane ring and to obtain a dehydrogenation reaction product. A method for producing hydrogen.   A hydrogen and dehydrogenation reaction product obtained by the method according to claim 6 and at least one selected from a hydrogen generation raw material composition before the dehydrogenation reaction are combusted, and the dehydrogenation reaction is performed using the combustion heat. A method for producing hydrogen, characterized in that:   A hydrogen production system, wherein hydrogen obtained by the method according to claim 6 and a dehydrogenation reaction product are separated by membrane separation.

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