JP2736592B2 - Method and apparatus for accelerating dehydrogenation reaction - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a dehydrogenation reaction of a hydrogen-containing compound such as an alcohol or a hydrocarbon, such as a decomposition reaction of methanol, a steam reforming reaction of methanol, or a reforming reaction of natural gas. The present invention relates to a promotion method and apparatus.

[0002]

2. Description of the Related Art As an example of a method for accelerating the dehydrogenation reaction of a hydrogen-containing compound, as described in JP-A-1-219001, a membrane selectively permeating hydrogen and a water vapor having excellent low-temperature activity are disclosed. using the reforming catalyst, the steam reforming reaction with H ₂ generated at the same time hydrocarbon to separate, and the method for producing hydrogen of high purity can be obtained in the H ₂ is known.

[0003]

In recent years, low-level exhaust heat and unused energy of exhaust gas at about 200 ° C. discharged from power plants, steelworks, chemical factories, etc., has been recovered and used for civilian (home use, Technology for business use) is required.
For this purpose, the recovered thermal energy is used for reforming hydrogen-containing compounds such as alcohols such as methanol and hydrocarbons.
It is conceivable that the heat is increased and converted into chemical energy by utilization for an endothermic reaction such as decomposition.

[0004] In order to realize effective use of thermal energy over a wide area, it is necessary to establish a high-efficiency heat transport technology from an industrial area to a residential / business area. In other words, in order to transport low-quality thermal energy of about 130-220 ° C discharged from factories to homes and business areas with low loss, and to effectively use it as a heat source, the development of technology using a chemical reaction that has never existed before is required. is necessary.

In order to convert low-quality heat energy into chemical energy by a decomposition reaction of a hydrogen-containing compound, for example, methanol, and to supply heat to a heat-demanding area, 130 to 22 tons are required.
The methanol decomposition reaction must be realized at a low temperature of about 0 ° C. However, the current state of the methanol decomposition reaction is
When no catalyst is used, a high temperature of 700 to 1000 ° C. is required, and when a current practical catalyst is used, the temperature is about 270 ° C. A technique for performing this at a low temperature of 130 to 220 ° C. and at a high reaction rate has not been established, and is a highly difficult subject.

In the decomposition reaction of methanol, even if a thermodynamic equilibrium state is assumed, a sufficient decomposition rate cannot be obtained with a low-temperature waste heat source as described above. Therefore, it is necessary to apply a non-equilibrium type membrane reactor which is not restricted by an equilibrium relationship so that a high decomposition rate can be obtained even at a low temperature.

[0007] Japanese Patent Application Laid-Open No. Hei 1-219001 describes that a non-equilibrium membrane reactor is constructed using a hydrogen selective separation membrane to produce high-purity hydrogen from natural gas. There is no mention of the effective use of low-temperature waste heat.

In order to solve the above-mentioned problems, in addition to a highly selective hydrogen separation membrane constituting a membrane reactor, a catalyst which maintains its activity even at a low reaction temperature, and if a smooth heat supply to the reaction system is possible. A heat transfer promoting type reactor partition wall structure is required.

[0009] The present invention has been made in view of the above-mentioned points, and has as its object to provide, for example, a dehydrogenation reactor (for example, a methanol reforming reactor) in a factory area,
By connecting a synthesis reactor (for example, methanol synthesis reactor) in the business area with a pipeline and transporting the product to form a chemical heat pump system,
It is an object of the present invention to provide a method and an apparatus for effectively utilizing low-temperature waste heat.

[0010]

In order to achieve the above-mentioned object, a method for accelerating a dehydrogenation reaction according to the present invention is directed to a method for dehydrogenation of a hydrogen-containing compound such as alcohols or hydrocarbons. In order to shift
Provided on the surface of the catalyst support layer integrated with the partition for the heat medium
The hydrogen produced by using the hydrogen selective separation membrane is separated and extracted out of the system, and a synthesis reaction is performed between the hydrogen and the produced carbon monoxide or carbon dioxide to recover reaction heat.
And at least a part of the heat medium for the dehydrogenation reaction, 13
Supply waste heat at a low temperature of 0 to 220 ° C, from waste heat source
The low-grade heat of the above is raised and recovered as the reaction heat of the synthesis reaction.
It is characterized by effective use.

In the above method, it is desirable to obtain high-purity (purity of 99.9% or more) hydrogen as one of the products and to separate and recover carbon monoxide or carbon dioxide as another product. In the dehydrogenation reaction, the reaction temperature is reduced,
In order to suppress side reactions such as carbon deposition, it is desirable to add steam. In the above-described method of adding steam, by controlling the amount of steam added, it is also possible to perform control following changes in the temperature of the supply heat source side of the reaction and / or changes in the amount of heat of the heating source. In the above method, it is a preferable example that the dehydrogenation reaction is a methanol decomposition / reforming reaction, and the low-temperature waste heat is factory waste heat at 130 to 220 ° C.

The dehydrogenation reaction accelerating device of the present invention is connected to a dehydrogenation reactor for performing a dehydrogenation reaction of a hydrogen-containing compound such as an alcohol or a hydrocarbon via a product gas transfer pipe to the dehydrogenation reactor. Generated hydrogen and carbon monoxide or carbon dioxide
A synthesis reactor for performing a synthesis reaction with carbon oxide, a product transfer pipe connecting the dehydrogenation reactor and the synthesis reactor, and a low-temperature 130-220 ° C. waste heat connected to the dehydrogenation reactor
From the waste heat supply pipe to supply low-grade heat from the waste heat source.
A chemical heat pump configured to raise and recover the temperature as reaction heat of the synthesis reaction , wherein the dehydrogenation reactor is separated from a heat medium.
It is a membrane reactor using a hydrogen selective separation membrane provided on the surface of a catalyst support layer integrated with a wall .

[0013] As described above, in the dehydrogenation reactor, a catalyst supporting layer integrated with the partition wall between the heat medium provided by providing a hydrogen selective separation film on a surface of the catalyst supporting layer, anti
Enhanced heat transfer reactor that enables smooth supply of heat to the reaction system
A wall structure can be realized, and as a result, about 130 to 220 ° C.
Even low-temperature waste heat can be used effectively . In addition, it is desirable that the dehydrogenation reactor be incorporated in a heat utilization system such as an exhaust heat recovery gas turbine, a fuel cell, or a high temperature gas reactor.

In a dehydrogenation reactor, a structure in which a hydrogen selective permeable metal thin film is formed on the surface of a porous sintered metal body is sometimes provided. In this case, it is desirable to use a palladium alloy thin film as the hydrogen selective permeable metal thin film.
In the above device, the dehydrogenation reactor is
A preferred example is a reforming reactor, and the synthesis reactor is preferably a methanol synthesis reactor.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the drawings. However, the dimensions, materials, shapes, relative positions and the like of the components described in this embodiment are as follows:
Unless there is a specific description, the scope of the present invention is not intended to limit the scope of the invention only to them, but is merely an illustrative example. In this embodiment, a case of a methanol reforming reaction as an example of a dehydrogenation reaction and a case of a methanol synthesis reaction as an example of a synthesis reaction will be described.

FIG. 1 shows a non-equilibrium reactor. 10
Is a membrane reactor having a heat medium (waste heat) layer 14 and a hydrogen selective permeable membrane 16 inside a palladium-based catalyst layer or the like. While supplying methanol to the catalyst layer 12, the heating medium layer is supplied with 130 to 220 discharged from the factory area.
The waste heat of about 3 ° C. is supplied, and CH ₃ OH
→ The reaction of CO + 2H ₂ occurs, CO is extracted as it is, and H ₂ is extracted through the hydrogen selective permeable membrane 16. Part of H ₂ and CO is used as a chemical raw material or the like, and the remainder is pipeline-transported to a methanol synthesis reactor to synthesize methanol. The reaction heat of the synthesis reaction at this time is effectively used for hot water supply and heating in the housing / business area, and waste heat energy in the factory area is transported. Note that steam may be supplied to the membrane reactor 10. Details will be described later.

FIG. 2 shows the effect of reducing the reaction temperature by the membrane reactor. In FIG. 2, a solid curve shows a case of an equilibrium reaction, and a broken curve shows a case of a non-equilibrium reaction in which generated H ₂ is separated and extracted. FIG.
Thus, in the case of the non-equilibrium reaction, it can be seen that the methanol decomposition rate increases at a low reaction temperature.

FIG. 3 shows an apparatus of the present invention, in which a methanol reforming reactor 20 and
A methanol synthesis reactor 24 connected via a production (reforming) gas (H ₂ , CO, CO ₂ ) transfer pipe 22 and a methanol transfer pipe connecting the methanol reforming reactor 20 and the methanol synthesis reactor 24 26 and a waste heat supply pipe 28 for supplying a heat source (factory waste heat) to the methanol reforming reactor 20 from outside the system constitute a chemical heat pump. The synthesis reaction heat from the methanol synthesis reactor 24 is used for consumer purposes such as hot water supply and heating. Reference numeral 30 denotes a synthesis reaction heat extracting means.

The methanol reforming reactor 20 is a membrane reactor using a hydrogen selective separation membrane. Then, H ₂ is separated by a hydrogen selective separation membrane to make it in a non-equilibrium state, to increase the methanol decomposition rate, and to generate H ₂ , CO, CO ₂
Is used as a chemical raw material or the like, and the remainder is supplied to a methanol synthesis reactor 24. In some cases, a part of the reformed gas is supplied to a fuel cell or the like to generate power, and CO ₂ may be recovered from exhaust gas. As described above, a so-called chemical heat pump is used to raise and recover low-grade heat supplied from a waste heat source by utilizing the inflow and outflow of heat accompanying a chemical change, so that a low-temperature level of about 130 to 220 ° C. Waste heat can be used effectively. In the above-described apparatus, the methanol reforming reactor 20 is installed in a factory area as an example, and the methanol synthesis reactor 24 is installed in a residential / business area as an example.

FIG. 4 shows the concept of a heat transfer mechanism of a conventional packed bed type reactor. The heating medium temperature T4 drops by Δt3 at the heat transfer boundary layer 40 of the heating medium fluid, enters the partition wall 42 at the temperature T3, drops by ΔT2, enters the catalyst packed layer 44 at the temperature T2, and drops by Δt1. To the reaction temperature T1. In this case, the temperature drop ΔT1 in the catalyst packed layer 44 is extremely large. This is because convection heat transfer and the like are performed in the catalyst packed layer 44 in addition to the conduction heat transfer.

FIG. 5 shows the concept of the heat transfer mechanism of the reactor with integral partition wall and catalyst according to the present invention. That is, the catalyst supporting layer 46 is provided integrally with the partition wall 42, and the hydrogen selective separation membrane 48 is provided on the surface of the catalyst supporting layer 46. When the reaction temperature T1 in FIG. 4 is made equal to the reaction temperature T1 ′ in FIG. 5, in the partition-wall-integrated catalyst layer in FIG. 5, only conduction heat transfer occurs, and Δt is smaller than the heat transfer in FIG. Very small. That is,
Δt1′≪ △ t1. Therefore, t4′≪t4, and the temperature of the heat medium may be low in FIG. Therefore, waste heat at a low temperature of about 130 to 220 ° C. can be effectively used. As described above, in the configuration shown in FIG. 5, it is possible to supply or remove heat required for the reaction while promoting the reaction.

FIG. 6 shows an example of use of the membrane reactor (for example, a methanol reformer) 10 in the present invention, and shows a system in which the membrane reactor 10 is combined with a gas turbine 50 to utilize heat. I have. It is also possible to combine with a diesel engine instead of a gas turbine.

FIG. 7 shows another example of use of the membrane reactor 10 in the present invention.
0 shows a system in which a combination of a fuel cell 0 and a molten carbonate fuel cell (MCFC) 52 is used.

FIG. 8 shows another example of the use of the membrane reactor in the present invention, in which CO ₂ is positioned as a hydrogen transfer medium, a methanol synthesizing apparatus 54 overseas, and a methanol conversion apparatus using waste heat in Japan. This is a combination of a quality device (membrane reactor) 10 and a CO ₂ recovery device 56. 58 is H for hydropower, solar cells, etc.
_{At the two} sources, the generated H ₂ is supplied to a methanol synthesizer 54 overseas to react with CO ₂ to synthesize methanol.

FIG. 9 shows still another example of use of the membrane reactor 10 according to the present invention. In place of the steam reformer in the high-temperature gas reactor, the membrane reactor 10 having the hydrogen selective separation membrane 48 according to the present invention is used.
By using, high-purity hydrogen having a purity of 99.9% or more can be produced without using a CO shift reactor, a CO ₂ separation device, a hydrogen purification device, and the like as in the related art.

In the dehydrogenation reaction, for example, when the methanol decomposition reaction is performed by the above method and apparatus, CH ₃ OH → CO + 2H ₂ (reaction temperature: 300 to 350)
C.) alone, the reaction temperature rises, and as a side reaction, the carbon deposition reaction 2CO → C + CO ₂ (reaction temperature: 300 to 350 ° C.) is apt to occur at the same time, which tends to cause a reduction in catalyst performance. For this reason, an appropriate amount of steam is added, and CH ₃ OH + H ₂ O → CO ₂ + 3H ₂ (reaction temperature: 20
(0 to 250 ° C.), thereby reducing the reaction temperature and suppressing side reactions such as carbon deposition. At this time, by controlling the amount of steam to be added, it is possible to perform control following changes in the temperature of the heat source supplied to the reaction and changes in the amount of heat of the heating source.

As a hydrogen-selective permeable membrane used in a membrane reactor for accelerating the dehydrogenation reaction, a Pd-based alloy membrane is used. The permeation rate of hydrogen depends on the hydrogen permeability of the membrane itself and the hydrogen permeability of the membrane. Determined by the thickness. At the research level, a thin film layer is formed on the surface of the ceramic-based porous support layer by plating, PVD, CVD, etc.
Since the reactor body is made of metal, there are fundamental technical problems in practical use, such as a large difference in thermal expansion, difficulty in structural mechanics, and poor sealing of H ₂ gas. Therefore, as shown in FIG. 10, a hydrogen selective permeable metal thin film 60 such as a Pd-based thin film is formed on a sintered metal porous body 62,
The end face of each constituent layer of the membrane reactor is provided with a complete and reliable H ₂ gas sealing effect by using conventional welding or brazing techniques without causing heat distortion. . Thus, the sintered metal porous body 6
The membrane reactor in which the metal thin film 60 having hydrogen selectivity is formed on the substrate 2 can improve the methanol decomposition rate even when low-temperature waste heat is used as a heat source.

[0028]

As described above, the present invention has the following effects. (1) In the dehydrogenation reaction step, one
Since hydrogen generated using the hydrogen selective separation membrane provided on the surface of the solidified catalyst support layer is separated and extracted out of the system ,
A thermodynamic non-equilibrium state is established, and the reaction is accelerated. Then, when performing a synthesis reaction with the generated hydrogen and the generated carbon monoxide or carbon dioxide to recover the heat of reaction ,
130 to 2 as a part or all of the heat medium of the dehydrogenation reaction.
Supply waste heat at a low temperature of about 20 ° C , and
The low-grade heat is recovered by raising the temperature as the reaction heat of the synthesis reaction.
Since the chemical heat pump system that effectively utilizes the waste heat is configured, waste heat at a low temperature of about 130 to 220 ° C. can be effectively used. (2) When steam is added to the dehydrogenation reaction, the reaction temperature can be reduced and side reactions such as carbon deposition can be suppressed. Further, by controlling the amount of steam addition, it is possible to perform control following changes in the temperature of the supply heat source and changes in the amount of heat of the heating source. (3) provided with a catalyst supporting layer integrally with the partition wall in the reactor, and a structure in which a hydrogen-selective separating membrane on the surface of this layer, the reaction
Heat transfer enhanced reactor that enables smooth heat supply to the system
Or partition wall structure , or on the surface of the sintered metal porous body,
Low reaction temperature with a structure formed by a hydrogen permselective metal thin film
With catalytic structure activity can be maintained even degree, 1
Waste heat at a low temperature level of about 30 to 220 ° C. can be effectively used.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing an example of a non-equilibrium reactor in an apparatus for performing a method for accelerating a dehydrogenation reaction of the present invention.

FIG. 2 is a graph showing a reaction temperature reduction effect of the non-equilibrium reactor shown in FIG.

FIG. 3 is a system diagram showing one embodiment of the accelerating device for a dehydrogenation reactor of the present invention.

FIG. 4 is a conceptual diagram of a heat transfer mechanism of a conventional packed bed type reactor.

FIG. 5 is a conceptual diagram of a heat transfer mechanism of the reactor with integral partition and catalyst in the present invention.

FIG. 6 is a system diagram showing an example of using a dehydrogenation reactor in the present invention.

FIG. 7 is a system diagram showing another use example of the dehydrogenation reactor in the present invention.

FIG. 8 is a system diagram showing another use example of the dehydrogenation reactor in the present invention.

FIG. 9 is a system diagram showing still another use example of the dehydrogenation reactor in the present invention.

FIG. 10 is an explanatory sectional view showing an example of a formation structure of a hydrogen selective permeable metal film in the apparatus of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Membrane reactor 12 Catalyst layer 14 Heat medium (waste heat) layer 16 Hydrogen selective permeable membrane 20 Methanol reforming reactor 22 Product gas transfer tube 24 Methanol synthesis reactor 26 Methanol transfer tube 28 Waste heat supply tube 30 Synthesis reaction heat extraction means 46 Catalyst layer integrated with partition wall 48 Hydrogen selective permeable membrane 60 Hydrogen selective permeable metal thin film 62 Sintered metal porous body

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Yoshiaki Takaya 1-1, Kawasaki-cho, Akashi-shi, Hyogo Kawasaki Heavy Industries, Ltd. Akashi Plant (72) Inventor Keizo Nakamura 2-4-1 Hamamatsucho, Minato-ku, Tokyo No. Kawasaki Heavy Industries, Ltd. Tokyo Head Office (56) References JP-A-1-219001 (JP, A) JP-A-59-77014 (JP, A) JP-A-4-108601 (JP, A)

Claims (10)

(57) [Claims] 1. In a dehydrogenation reaction of a hydrogen-containing compound such as an alcohol or a hydrocarbon, the dehydration reaction is integrated with a partition wall with a heat medium to shift the thermodynamic equilibrium and promote the reaction.
The generated hydrogen is separated using a hydrogen selective separation membrane provided on the surface of the catalyst supporting layer , extracted to the outside of the system, and a synthesis reaction is performed between the hydrogen and the generated carbon monoxide or carbon dioxide to cause a reaction heat. When recovering , as at least a part of the heat medium of the dehydrogenation reaction, a low-temperature waste heat of 130 to 220 ° C. is supplied , and the low-grade heat from the waste heat source is used for the synthesis reaction.
A method for accelerating a dehydrogenation reaction, which comprises recovering a temperature as a reaction heat and effectively utilizing the recovered heat . 2. The method according to claim 1, wherein high purity hydrogen is obtained as one of the products, and carbon monoxide or carbon dioxide is separated and recovered as another product. 3. The method for accelerating a dehydrogenation reaction according to claim 1, wherein steam is added in the dehydrogenation reaction in order to reduce a reaction temperature and suppress a side reaction such as deposition of carbon. 4. By controlling the amount of steam to be added,
4. The method for accelerating a dehydrogenation reaction according to claim 3, wherein control is performed in accordance with a temperature change on a supply heat source side of the reaction and / or a heat amount change of a heating source. 5. The dehydrogenation reaction is methanol decomposition and reforming reactions, low levels of waste heat of the dehydrogenation reaction according to claim 1, 2, 3 or 4, wherein it is a factory waste heat How to promote. 6. A dehydrogenation reactor for performing a dehydrogenation reaction of a hydrogen-containing compound such as alcohols or hydrocarbons , and produced water connected to the dehydrogenation reactor via a product gas transfer pipe.
A synthesis reactor for performing a synthesis reaction between hydrogen and carbon monoxide or carbon dioxide, a compound transfer pipe connecting the dehydrogenation reactor and the synthesis reactor, and 130 to 220 connected to the dehydrogenation reactor
℃ low level waste heat from a waste heat supply pipe for supplying the waste
Temperature rise from low-grade heat from heat source as reaction heat of the synthesis reaction
The chemical heat pump to be recovered is constituted, and the dehydrogenation reactor has a surface of a catalyst supporting layer integrated with a partition wall with a heat medium.
A device for promoting a dehydrogenation reaction, characterized in that it is a membrane reactor using a hydrogen selective separation membrane provided in the system. 7. A dehydrogenation reactor comprising an exhaust heat recovery gas turbine,
7. The device for accelerating a dehydrogenation reaction according to claim 6, wherein the device is incorporated in a heat utilization system such as a fuel cell or a high-temperature gas reactor. 8. The dehydrogenation reactor according to claim 6, wherein a structure in which a hydrogen selectively permeable metal thin film is formed is provided on the surface of the porous body of the sintered metal. apparatus. 9. The apparatus for accelerating a dehydrogenation reaction according to claim 8, wherein the hydrogen selectively permeable metal thin film is a thin film of a palladium alloy. 10. A dehydrogenation reactor is methanol decomposition and reforming reactor, the synthesis reactor of the dehydrogenation reaction according to claim 6, 7, 8 or 9, wherein the methanol synthesis reactor Promoting device.