JPS6384629A - Heat exchanger type reactor used for performing reaction accompanying generation of hydrogen - Google Patents

Abstract

PURPOSE:To enhance degree of conversion of a gaseous raw material by arranging a porous material pipe, a packed catalytic layer and an outer cylinder of a catalytic layer wherein a passing space of a heating medium is formed to the periphery and providing both a discharge port of H2-enriched gas permeated and separated via the porous material pipe and a discharge port of impermeated gas. CONSTITUTION:For example, in case of the dehydrogenating reaction of cyclohexane, gasified cyclohexane is fed through an inlet 1 of a reactor main body and distributed to introduction paths 2 of catalytic layers. Cyclohexane is subjected to dehydrogenating reaction in catalytic packed layers 3 and converted into benzene and hydrogen. Hydrogen selectively permeates porous material pipes 4 and is drawn into the pipes and discharged to the outside of the system as permeated gas enriched with H2 via discharge paths 9 of permeated gas. On the other hand, impermeated gas enriched with benzene is discharged to the outside of the system via discharge paths 8 of impermeated gas. Furthermore a heating medium is fed through an introduction path 6 thereof and subjected to heat exchange in the inside of the reactor main body 5 and thereafter discharged to the outside of the system through a discharge path 7 of the heating medium.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a heat exchanger type reactor used for carrying out reactions involving the generation of hydrogen.

[Conventional technology]

A typical reaction that involves the generation of hydrogen is a dehydrogenation reaction. This dehydrogenation reaction is an important reaction in petroleum refining, petrochemistry, and organic synthesis chemistry, and includes the following reactions.

■ Dehydrogenation of paraffins and olefins to olefins and diolefins ■ Dehydrogenation of alkylaromatics to alkenylaromatics ■ Dehydrogenation of alkyl heterocyclics to alkenyl heterocyclics ■ Dehydrogenation of alcohols to aldehydes or ketones ■ Dehydrogenation of heterocyclic compounds ■ Dehydrogenation of cycloparaffins (su7ten) to cycloolefins and aromatics■ Cyclization dehydrogenation of sevenrafins and olefins to aromatics accompanied by the generation of nine hydrogens The reaction is CO and H2O
There is a shift reaction due to

Among reactions that involve the generation of hydrogen, dehydrogenation is one of the industrially important reactions, as seen in the production of styrene, butadiene, etc. All of these dehydrogenation reactions are endothermic reactions, and therefore a large amount of heat must be supplied at high temperatures. Under such high-temperature conditions, in addition to dehydrogenation, decomposition of hydrocarbons is also likely to occur, and this is particularly noticeable with metal catalysts, and the deterioration of catalyst activity due to carbon deposition is significant, making it difficult to perform in industrial processes. 0aBNi (PO4) is stable even with reducing metal oxides and high temperatures.
) 6 etc. are used as catalysts.

Also, since the dehydrogenation reaction is a reaction in which the number of moles increases,
In industrial operations, where low pressure is preferred from an equilibrium standpoint, high temperature and low pressure conditions are achieved by introducing large amounts of high temperature steam into the feed stream, and at the same time, the coexistence of this large amount of steam causes coke to form on the catalyst surface. This suppresses the accumulation of such substances and also prevents the catalyst surface from changing to an excessively reduced state, thereby stably maintaining the catalyst activity.

The present inventors previously proposed in Japanese Patent Application No. 60-042413 a method for converting hydrogen in hydrogen-containing gas into cyclohexane and storing it, and then extracting hydrogen from the cyclohexane again before use, but the dehydrogenation reaction of cyclohexane too,
Similar to the production of styrene and butadiene mentioned above, problems such as replenishment of a large amount of heat at high temperatures and carbon precipitation occur.

[Problem that the invention seeks to solve]

The dehydrogenation reaction of hydrocarbons is a highly endothermic reaction and requires high reaction temperatures due to thermodynamic equilibrium constraints. Therefore, in order to carry out this reaction, it is necessary to supply a large amount of heat at a high temperature. In addition, since the reaction temperature is high, in addition to dehydrogenation, decomposition of hydrocarbons also occurs quickly, especially on base metal catalysts such as Fe4'Nl, and the activity of the catalyst deteriorates due to carbon deposition. Significant.

An object of the present invention is to solve the above-mentioned problems and provide an efficient heat exchanger type reactor that allows the dehydrogenation reaction to proceed at low temperatures and accelerates the reaction rate.

[Means for solving problems]

A ninth technical means of the present invention to achieve the above object is to provide a catalyst packed layer on the outer peripheral surface of a porous material tube in a reaction apparatus for carrying out a reaction accompanied by hydrogen generation in the presence of a catalyst, The catalyst packed layer is covered with a catalyst layer outer cylinder around which a heat medium circulation space is formed, and the porous material tube is provided with permeation and separation from the catalyst packed layer through the wall of the porous material tube. In addition, the catalyst packed bed is provided with an inlet path for raw material gas and an outlet path for unpermeated gas in the porous material pipe, and the circulation space is also provided with an inlet path for heat transfer medium and an outlet path. This is a heat exchanger type reactor used for carrying out a reaction accompanied by the generation of hydrogen, characterized in that it is provided with a passage.

[For production]

In this way, in the present invention, while a reaction accompanied by hydrogen generation occurs in the presence of a catalyst, on the other hand, hydrogen generation is caused by a porous material tube placed in direct contact with a catalyst packed bed. Hydrogen produced in the accompanying reaction is immediately and selectively drawn out of the system to shift the chemical equilibrium, thereby increasing the equilibrium conversion rate, lowering the reaction temperature, and accelerating the reaction rate.

Furthermore, by filling the tube with the catalyst to form a packed bed, a large amount of heat can be efficiently supplied from outside the packed bed. Note that as the material for the porous material tube in the present invention, glass, ceramics, sintered metal powder, metal foil, etc. can be used, and glass is excellent in terms of workability.

[Implementation row]

Embodiments of the present invention will be explained below with reference to the drawings.

FIG. 1 is a side sectional view of a heat exchanger type reactor.

4 is a porous material tube, a catalyst packed layer 3 is formed so as to directly surround the outer peripheral surface of this tube, and these catalyst packed layers 3
are covered by a catalyst layer outer cylinder 13, and are in indirect contact with the heat medium circulation space 14 via this outer cylinder 13, respectively. One end side of the catalyst packed bed 3 is a catalyst bed introduction path 2 for reaction gas.
, and the other end side forms a porous material pipe non-permeated gas discharge passage 8 so that non-permeated off-gas generated by a reaction accompanied by hydrogen generation and not permeated into the porous material pipe 4 can flow out. are doing. In addition, the porous material tube 4 is provided with a porous material tube permeation gas discharge passage 9 in order to take out hydrogen-rich gas mainly composed of hydrogen generated in the catalyst packed bed 3 and separated by passing through the tube wall. It is being

In this way, the porous material tube 4t and the catalyst layer outer tube 13 which is provided inside the porous material tube 4 and forms the catalyst packed layer 3 surrounding the outer peripheral surface of the porous material tube 4 are considered as one unit, and the heat between these units is The gold films are arranged in parallel inside the reactor main body 5 across the gap to form a medium circulation space 14, and the heat medium introduction passage 6 and discharge passage 7 are provided in the circulation space 14.

The reactor main body 5 includes a reactor main body port 1 for introducing reaction gas gold, and a reactor main body permeated gas outlet 10 for combining and taking out the hydrogen-rich gas that has permeated into the porous material tube 4. This heat exchanger type reactor is then used to carry out all the reactions for hydrogen generation. The case will be specifically explained along with its action using the dehydrogenation reaction of cyclohexane as an example.

By reacting hydrogen in a hydrogen-containing gas with benzene,
In order to extract hydrogen from cyclohexane again after storing it as liquid cyclohexane, the cyclohexane is vaporized and then supplied from the reactor body 1 shown in FIG. distributed to. The catalyst packed bed 3 has a cylindrical shape and is installed inside the reactor main body 5. The cyclohexane supplied from the catalyst bed introduction passage 2 is converted into benzene through a dehydrogenation reaction in the catalyst packed bed 3. becomes hydrogen. Hydrogen selectively permeates through the porous material tube 4 and is extracted into the tube.
The hydrogen-rich permeate gas is passed through the porous material pipe permeate gas discharge passage 9 and the permeate gas outlet 10 of the reactor main body, and is discharged to the outside of the system by the vacuum pump 12. This vacuum pump 1
2 is an auxiliary means for drawing out the permeate gas,
It may be unnecessary depending on the operating conditions. On the other hand, the penzene-rich unpermeated gas is discharged to the outside of the system through the porous material tube unpermeated gas discharge passage 8 and the unpermeated gas outlet 11 of the reactor main body.In the five-line arrangement, heat is supplied to the catalyst packed bed 3 Steam is used as a heat medium for the reaction, and the steam is supplied from the heat medium introduction path 6, performs heat exchange inside the reaction device 5, and is then discharged from the system from the heat medium discharge path 7. , filled with Pt-At203 type catalyst as a catalyst, pressure 1 kf/c+JG, temperature 2-50°C.

In the case where only the dehydrogenation reaction is performed by the conventional method without selective hydrogen withdrawal from the porous material tube 4 under the conditions of S, V, 90 hr-', cyclohexane is converted into benzene and hydrogen. The conversion rate was about 18%, but when hydrogen was extracted from the porous material tube 4 by 30% of the supplied cyclohexane flow rate, the conversion rate increased to 95%. As described above, by using the reaction apparatus of the present invention, hydrogen generated in the reaction system is selectively extracted, so the reaction is promoted and the conversion rate from the raw material gas is greatly improved.

In the above implementation rows, the holes indicate rows in which steam is used as a heating medium for the catalyst, but the heating medium used in the present invention is not limited to steam, and examples of heating media include combustion exhaust gas, heating furnace exhaust gas, etc. A gaseous heat medium or a liquid heat medium that exchanges heat with these exhaust gases may be used. In addition, in the embodiment, the flow type of the heating medium was cocurrent with the flow of the reaction gas, but counterflow may be used as long as heat exchange can be carried out efficiently.

In the above explanation, we focused on dehydrogenation of hydrocarbons, but this reactor is suitable for not only dehydrogenation of hydrocarbons, which is an endothermic reaction, but also exothermic reactions accompanied by hydrogen generation, such as the shift reaction of CO. It can also be applied to In this case, by using a refrigerant as a heat medium, the heat of reaction can be efficiently recovered to the outside of the system.

〔Effect of the invention〕

Since the present invention has the above configuration and operation, it has the following effects.

(a) By selectively extracting hydrogen, the reaction temperature can be lowered.

(b) The conversion rate can be improved by selectively extracting hydrogen.

(c) Since the reaction temperature is lowered, carbon precipitation due to decomposition of hydrocarbons with base metal catalysts such as Ni and Fe can be prevented. (d) Heat exchange becomes easy and the reaction state can be maintained stably.

(e) Since hydrogen generation and separation can be performed simultaneously, steps can be omitted and the equipment can be made more compact.

[Brief explanation of the drawing]

FIG. 1 is a side cross-sectional view of a heat exchanger type reactor in accordance with the present invention. 1... Reactor main body inlet, 2... Catalyst layer introduction path, 3
... Catalyst packed bed, 4... Porous material tube, 5... Reactor main body, 6... Heat medium introduction path, 7... Heat medium discharge path, 8... Porous material tube Unpermeated gas exhaust path, 9...
- Porous material pipe permeated gas discharge path, 10... Reactor main body permeated gas outlet, 11... Reactor main body unpermeated gas outlet, 12... Vacuum pump, 13... Catalyst layer outer cylinder, 1
4... Heating medium distribution space agent Patent attorney Masamitsu Akisawa and 1 other person

Claims (1)

[Claims] In a reaction device for carrying out a reaction accompanied by the generation of hydrogen in the presence of a catalyst, a catalyst-packed layer is provided on the outer peripheral surface of a porous material tube, and a catalyst layer outer cylinder with a heat medium circulation space formed around it. The porous material tube is provided with a discharge path for hydrogen-rich gas that has been permeated and separated from the catalyst packed layer through the wall of the porous material tube, and the catalyst packed layer is covered with a A reaction accompanied by generation of hydrogen, characterized in that an introduction path for raw material gas and a discharge path for unpermeated gas of the porous material pipe are provided, and furthermore, an introduction path and a discharge path for a heat medium are provided in the circulation space. A heat exchanger type reaction device used to carry out.