JPH0640704A - Reactor for dehydrogenation reaction - Google Patents

Abstract

PURPOSE:To improve the thermal efficiency of the reactor by disposing several heat exchangers in the reactor and using the waste heat of combustion waste gas after heating the reforming reactor tube to preheat the air for combustion and the source material gas, and using the sensible heat of the product hydrogen to preheat the sweep gas. CONSTITUTION:The source gas 1 containing (oxygen-contg.) hydrocarbon and steam is preheated in a preheating heat exchanger 22 and then introduced to a reforming reactor 2. At same time, air 6 and methane 4A are supplied to a burner 11 attached to the center part of the reforming reactor 2 to be burned with a combustion catalyst 3 and the heat required for the reforming reaction is supplied to the reactor tube 2. Thus, the source gas 1 is reformed into hydrogen-contg. gas and then hydrogen is selectively recovered by a hydrogen separation means 14. The waste heat of the combustion waste gas 12 after heating the reactor tube 2 is supplied to the heat exchangers 22 and 23 and used to preheat the source gas 1 and the air 17 for combustion. Further, the sensible heat of the product hydrogen gas is supplied to the heat exchanger 24 and effectively used to preheat the sweep gas 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reactor for dehydrogenation reaction which is advantageously applied to the chemical industry and fuel cells.

[0002]

2. Description of the Related Art A raw material supply port and a product extraction port are provided,
In a reactor having a reforming catalyst filled inside and a heating means inside or outside the reactor, a means for selectively separating hydrogen is installed in the reforming catalyst packed bed of the reactor, and the catalyst is introduced from outside the reaction tube. By supplying the heat necessary for the reaction by combustion and removing a part of the hydrogen of the reaction product from the inside of the reaction tube, it is possible to obtain a conversion rate equal to or higher than the equilibrium conversion rate at the same time by causing the reaction to occur simultaneously. A possible reactor for dehydrogenation reaction has been conventionally proposed.

The hydrogen-selective separation membrane used in the means for selectively separating hydrogen is (1) a polymer membrane such as a polyimide membrane, (2) porous glass, (3).
There are proposed porous glass coated with palladium or a palladium alloy thin film, (4) porous metal coated with a palladium or palladium alloy thin film, and the like.

The above-mentioned reactor for dehydrogenation reaction can obtain a high conversion at a temperature lower than usual, but for that purpose, in the reactor, the heat required for the reaction is not generated by the burner combustion but by the catalyst. It is known that it is desirable and effective to feed by combustion and keep the reaction temperature low.

FIG. 2 shows a structural example of a conventional reactor for steam reforming reaction of methane. In the case of this conventional reactor, the combustion gas after heating the reforming reaction tube 2 is discharged from the combustion exhaust gas tube 12 to the outside of the reactor, and the exhaust heat is not effectively recovered.
Even when the sweep gas is supplied, the high-temperature product hydrogen gas is discharged from the hydrogen recovery nozzle 5 to the outside of the reactor without heat exchange with the sweep gas, and the sensible heat thereof is not effectively recovered.

[0006]

In the case of the conventional preheating of the raw material gas and combustion air illustrated in FIG. 2 and the flow of the sweep gas, heat exchangers for the purpose of preheating the sweep gas are respectively provided outside the reactor. The reactor is provided with a heating means inside or outside, and a hydrogen separation means having a selective hydrogen separation function is installed in the reaction tube, and the heat necessary for the reaction is supplied from the outside of the reaction tube by catalytic combustion, and the reaction tube is heated. The reactor which carries out the dehydrogenation reaction while excluding a part of the hydrogen of the reaction product has the following drawbacks.

(1) When the preheating of the raw material gas and the combustion air and the flow of the sweep gas are made to flow, heat exchangers for preheating the sweep gas are installed outside the reactor, so that heat loss from the reactor is reduced. Many have poor thermal efficiency. As a result, heat loss from the reactor is reduced and thermal efficiency is improved, so that heat insulation work for the piping and the reactor is increased. (2) Moreover, since the above heat exchangers are installed outside the reactor, the number of equipment, piping, heat insulation work, etc. increases,
Increasing the size and complexity of the entire system is inevitable.

In view of the above-mentioned state of the art, the present invention intends to provide a dehydrogenation reaction reactor in which the drawbacks of the conventional dehydrogenation reaction reactor are eliminated.

[0009]

The present invention provides a plurality of reformers for reforming a raw material gas of a hydrocarbon or an oxygen-containing hydrocarbon and steam into a hydrogen-containing gas and separating the hydrogen by a hydrogen separating means having a hydrogen separating function. A reaction tube, heating means provided in the center of the plurality of reforming reaction tubes, fuel supply means for catalytic combustion provided around the heating means, and fuel supplied from the fuel supply means. Dehydration, characterized in that it comprises a combustion catalyst arranged around the reforming reaction tube and a heat exchanger for preheating the raw material gas and the combustion air and the preheating of the sweep gas inside the reactor. It is a reactor for elementary reaction.

[0010]

In the dehydrogenation reaction reactor, the following effects can be expected by installing heat exchangers for preheating the source gas and the combustion air and the preheating of the sweep gas inside the reactor.

(1) Since heat exchangers for the purpose of preheating the source gas and the combustion air and the preheating of the sweep gas are installed inside the reactor and are combined, the thermal efficiency is improved.
A highly efficient reactor with less heat loss from the reactor can be provided. Further, as a result, the heat insulation work for the piping and the reactor can be minimized. (2) Since the heat exchanger is not required outside the reactor,
The number of equipment, piping, and heat insulation work is greatly reduced, and the entire system can be made smaller and simpler.

[0012]

EXAMPLE An example of the present invention will be described with reference to FIG. 1 in the case of a methane steam reforming reaction reactor as an example. The reforming raw material gas in which methane and steam are mixed is introduced from the raw material gas supply pipe 1 into the reforming reaction pipe 2 through the heat exchanger 22 for preheating the raw material gas, and the reforming catalyst 8 mainly supplies hydrogen and carbon dioxide. It is reformed into the product gas as an ingredient.
Of this product gas, hydrogen is selectively recovered by a hydrogen separation means having a selective hydrogen separation function, in this embodiment, a circular tubular hydrogen separation membrane 14, and discharged from the hydrogen recovery nozzle 5 as product hydrogen gas. At this time, in order to perform the recovery more effectively and to obtain a higher reaction conversion rate,
A sweep gas pipe 10 is inserted inside the circular tubular hydrogen separation membrane 14 so that a sweep gas composed of water vapor, hydrogen, nitrogen or the like is caused to flow from the sweep gas supply nozzle 9. In this case, in order to effectively utilize the sensible heat of the separated product hydrogen gas, the coil-shaped heat exchanger 24 is installed in the hydrogen recovery chamber 16 to raise the temperature of the sweep gas. On the other hand, the unreacted raw material gas containing carbon dioxide after hydrogen separation is discharged from the unreacted gas discharge pipe 13.

As a heat source necessary for this reforming reaction, a combustion catalyst pipe 19 which is a main part of the starting pilot burner 11 and the combustion catalyst 3 (lattice shape) is built in the central portion of the reactor, and the air supply pipe 6 Air and methane supplied from the methane pipe 4A are made into high-temperature combustion gas by the combustion catalyst 3 (lattice shape) and flow out from the combustion catalyst pipe 19. Needless to say, the same effect can be obtained by using the combustion catalyst 3 (lattice shape) as a combustion burner. On the other hand, through the fuel gas supply pipe 20 from the methane pipe 4B, the fuel gas preheated by heat exchange with the combustion catalyst pipe 19 is ejected from the fuel gas dispersion hole 21 opened appropriately in the fuel gas supply pipe 20.
This fuel gas is uniformly dispersed and mixed with the combustion gas flowing in from the above-mentioned combustion catalyst pipe 19, and is multi-stage burned by the combustion catalyst 7 (pellet shape) arranged around the reforming reaction pipe 2.
The reforming reaction tube 2 is sufficiently supplied with heat necessary for the reaction. Next, the combustion gas, which is still sufficiently high in temperature after heating the reforming reaction tube 2, flows into the jacket 15 provided on the outer periphery of the body from above, and the heat exchangers 2 for preheating the raw material gas are respectively arranged in a coil shape.
2. Subsequently, heat is exchanged with the heat exchanger 23 for preheating combustion air and each series to recover the exhaust heat, and the exhaust heat becomes a low temperature and is discharged from the combustion exhaust gas pipe 12. More specifically, the reforming raw material gas is introduced from the raw material gas supply pipe 1 which penetrates the jacket 15 and is connected to the heat exchanger 22, and heat-exchanges with the combustion gas to be heated and supplied to the reforming reaction pipe 2. To be done. Combustion air is introduced from an air inlet 17 that penetrates through the jacket 15 and is connected to a heat exchanger 23, and is then heated by exchanging heat with the combustion gas to flow out from an air outlet 18, and the air supply pipe described above. 6 is introduced into the reactor as high temperature combustion air.

Comparative data of the apparatus of the above embodiment and the conventional reactor for dehydrogenation reaction shown in FIG. 2 are shown below.

[0015]

[Table 1]

[0016]

The present invention has the following effects. (1) A highly efficient reactor in which heat efficiency is improved and heat loss from the reactor is small because heat exchangers for the purpose of preheating the raw material gas and combustion air and the preheating of the sweep gas are installed and combined inside the reactor. Can be provided. Further, the heat insulation work for the piping and the reactor can be minimized. (2) Since the heat exchanger is not required outside the reactor,
The number of equipment, piping, and heat insulation work has decreased significantly,
The whole system can be miniaturized and simplified.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a methane steam reforming reaction reactor according to an embodiment of the present invention.

FIG. 2 is a block diagram of a conventional reactor for methane steam reforming reaction.

Claims (1)

[Claims] 1. A plurality of reforming reaction tubes for reforming a raw material gas of a hydrocarbon or an oxygen-containing hydrocarbon and steam into a hydrogen-containing gas and separating the hydrogen by a hydrogen separating means having a hydrogen separating function, and a plurality of the reforming reaction tubes. Heating means provided at the center of the reforming reaction tube, fuel supply means for catalytic combustion provided around the heating means, and fuel supplied from the fuel supply means around the reforming reaction tube. In the reactor for dehydrogenation reaction, which comprises the arranged combustion catalyst, the exhaust heat of the combustion exhaust gas after heating the reforming reaction tube is used to preheat the raw material gas and the combustion air,
Further, in order to effectively use the sensible heat of the product hydrogen gas for preheating the sweep gas, a dehydrogenation reactor is provided with a heat exchanger inside the reactor.