JPH09165202A - Steam reformer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To raise a yield of hydrogen from a gas obtained by mixing steam with methane. SOLUTION: This reformer is equipped with a catalyst tube 24 which is arranged in a high-temperature primary gas 28 circulating atmosphere and comprises one end from which a secondary gas 29 obtained by mixing steam with methane and the other closed end, a flow channel forming pipe 26 which is inserted into the catalyst pipe 24 so as to comprise one end positioned in the vicinity of the bottom of the catalyst pipe 24 and the other end positioned outside of the catalyst pipe 24 and a catalyst 27 packed into a space between the inner face of the catalyst pipe 24 and the outer face of the flow channel forming pipe 26. A heat transfer promoter 34 to make the flow of the secondary gas 29 take a long way around is placed in the inside of the flow channel forming pipe 26. While the secondary gas 29 after the reaction is bypassed and flows upward in the interior of the flow channel forming pipe 26 with forming a turbulence on a wall face of the flow channel forming pipe 26, the heat energy which retains the secondary gas 29 having finished the reaction is efficiently transferred to the secondary gas 29 during the reaction to increase a formed amount of hydrogen.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a steam reformer for producing hydrogen from steam and a hydrocarbon gas such as methane.

[0002]

2. Description of the Related Art An example of a steam reformer conventionally used for producing hydrogen from steam and a hydrocarbon gas such as methane will be described with reference to FIG.

Reference numeral 1 denotes a hollow reformer main body, and the reformer main body 1 has a vertically extending tubular body 2 having a lower end portion having an end plate 3
Is fixed and closed, and is supported by a fixed structure 5 such as a pedestal by a skirt portion 4 provided on the outer side of the body portion 2.

A primary fluid inlet nozzle 6 is provided near the lower end of the body 2 in a radial direction from the outside to the inside of the body 2, and near the upper end of the body 2, the body 2 is provided. Is provided with a primary fluid outlet nozzle 7 that communicates radially from the inside to the outside.

A tube sheet 8 is provided at the upper end of the body portion 2, and an inner cylinder 9 is inserted inside the body portion 2 coaxially with the body portion 2. Is fixed to the bottom surface of.

A primary fluid inlet pipe 10 is provided near the lower end of the inner cylinder 9 so as to communicate radially from the outer side to the inner side of the inner cylinder 9 so as to be positioned coaxially with the primary fluid inlet nozzle 6. In the vicinity of the upper end of the cylinder 9, a primary fluid outlet pipe 11 that communicates radially from the inside to the outside of the inner cylinder 9 is provided so as to be positioned coaxially with the primary fluid outlet nozzle 7.

Furthermore, a space between the outer surface of the inner cylinder 9 and the inner surface of the body portion 2 and a space between the inner bottom surface of the end plate 3 and the lower surface of the tube sheet 8 are filled with a heat insulating material 12. ing.

A fluid chamber forming cylinder 13 having a diameter substantially the same as that of the body portion 2 is provided on the upper surface of the tube sheet 8 so as to have the same axis as the body portion 2, and the lower end portion of the fluid chamber forming body 13 is formed. The upper end of the body portion 2 is fixed by a fastening means 14 such as a bolt, and the tube sheet 8 is firmly sandwiched between the lower end portion of the fluid chamber forming body 13 and the upper end portion of the body portion 2.

A secondary fluid inlet nozzle 15 is provided near the lower end of the fluid chamber forming cylinder 13 so as to communicate radially from the outside to the inside of the fluid chamber forming cylinder 13, and the fluid chamber forming cylinder 13 is also provided.
A secondary fluid outlet nozzle 16 is provided near the upper end of the fluid chamber forming cylinder 13 so as to communicate radially from the inside to the outside.

Further, inside the fluid chamber forming cylinder 13, an upper inner cylinder 17 is provided coaxially with the fluid chamber forming cylinder 13 and separately above and below.

In the vicinity of the lower end of the upper inner cylinder 17, a secondary fluid inlet pipe 18 which communicates radially from the outside to the inside of the upper inner cylinder 17 is positioned coaxially with the secondary fluid inlet nozzle 15. A secondary fluid outlet pipe 19 is provided near the upper end of the upper inner cylinder 17 and communicates radially from the inside to the outside of the upper inner cylinder 17 so as to be positioned coaxially with the secondary fluid outlet nozzle 16. It is provided in.

Further, inside the fluid chamber forming cylinder 13, a tube plate 2 that is in contact with the inner surface of the fluid chamber forming cylinder 13 at a position above the secondary fluid inlet pipe 18 and below the secondary fluid outlet pipe 19.
0 is provided. A reformer lid 21 is fixed to the upper end of the fluid chamber forming cylinder 13 by fastening means 22 such as bolts.

Further, in a space surrounded by the outer surface of the upper inner cylinder 17, the inner surface of the fluid chamber forming cylinder 13, the outer periphery of the upper surface of the tube sheet 8, and the outer periphery of the lower surface of the reformer lid 21. Is filled with a heat insulating material 23.

Inside the inner cylinder 9, a plurality of vertically extending catalyst tubes 24 (only one is shown in the drawing) are arranged, and a large number of baffle plates 25 and tie rods provided inside the inner cylinder 9 (see FIG. It is supported by a steady rest (not shown).

The upper end of the catalyst tube 24 is inscribed and fixed in a tube hole formed in the tube sheet 8.
It has a closed shape.

Inside each catalyst tube 24, a flow path forming tube 26 is provided.
Is inserted so as to be loosely fitted, and the upper end of the flow path forming tube 26 is internally fixed to a tube hole formed in the tube sheet 20.
The lower end of the flow path forming pipe 26 opens near the lower end of the catalyst pipe 24.

A pellet for producing hydrogen (H ₂ ) from steam (H ₂ O) and methane (CH ₄ ) is provided between the outer surface of each flow path forming tube 26 and the inner surface of the catalyst tube 24. The catalyst 27 is filled.

In the conventional steam reformer described above, when a high temperature primary gas 28 such as helium (He) is supplied to the primary fluid inlet pipe 10, the primary gas 28 causes the inside of the inner cylinder 9 to reach the baffle plate 25. While being blocked and circumvented, it flows from the lower side to the upper side, and flows out from the primary fluid outlet pipe 11 to the outside.

On the other hand, water vapor (H ₂
When the secondary gas 29 in which O) and methane (CH ₄ ) are mixed is supplied, the secondary gas 29 is formed by the inner side surface of the fluid chamber forming cylinder 13, the upper surface of the tube sheet 8 and the lower surface of the tube sheet 20. Through the fluid chamber 30 that flows through the inner surface of the catalyst tube 24 and the flow path forming tube 26.
Flows through the inside of the catalyst 27, which is filled between the outer surface and the outer surface, from the upper side to the lower side.

At this time, steam (H ₂ O) and methane (CH ₄ ) contained in the secondary gas 29 are generated by the catalyst 27 and the thermal energy transferred from the primary gas 28 through the catalyst pipe 24. Reacts with hydrogen (H ₂ ) and carbon monoxide (C
O) and are generated.

Also, carbon monoxide (CO) produced by the modification reaction and water vapor (H ₂ O) contained in the mixed gas.
From, hydrogen (H ₂ ) and carbon dioxide (CO ₂ ) are generated.

The secondary gas 29 containing hydrogen (H ₂ ) as a main component flows into the inside of the passage forming pipe 26 from the lower end of the passage forming pipe 26, and the inside of the passage forming pipe 26 is inspected from below. After flowing upward, the inner surface of the fluid chamber forming cylinder 13 and the tube sheet 2
0 through the fluid chamber 31 formed by the upper surface of the reformer lid 21 and the lower surface of the reformer lid 21, and flows out from the secondary fluid outlet pipe 19 to the outside.

As a result, the secondary gas 29 mixed with water vapor (H ₂ O) and methane (CH ₄ ) supplied to the secondary fluid inlet pipe 18 is hydrogen (H ₂ ) from the secondary fluid outlet pipe 19. Is collected as the secondary gas 29 containing as a main component and used in a chemical plant or the like.

[0024]

In recent years, steam (H
There is an increasing demand for increasing the collection rate of hydrogen (H ₂ ) generated from a gas in which ₂ O) and methane (CH ₄ ) are mixed.

FIG. 6 shows the secondary after the reaction is performed by flowing from the upper side to the lower side of the catalyst 27 filled between the inner surface of the catalyst tube 24 and the outer surface of the flow path forming tube 26. Gas 2
9 is a graph showing the relationship between the temperature of 9 and the residual amount of methane in the reacted secondary gas 29.
It can be seen that the higher the temperature is, the smaller the remaining amount of methane (CH ₄ ) is.

A small amount of methane (CH ₄ ) means that more methane (CH ₄ ) reacts with steam (H ₂ O) to produce more hydrogen (H ₂ ). Therefore, the secondary gas after flowing through the inside of the catalyst 27 filled between the inner surface of the catalyst tube 24 and the outer surface of the flow path forming tube 26 from the upper side to the lower side and reacting Two
If the temperature of 9 is increased, the collection rate of hydrogen (H ₂ ) will be improved.

From this point of view, the present invention circulates from the upper side to the lower side of the catalyst filled between the inner side surface of the catalyst tube and the outer side surface of the flow path forming tube to react. It is an object of the present invention to provide a steam reformer in which the temperature of the subsequent secondary gas is increased and the hydrogen collection rate from the gas in which steam and methane are mixed is improved.

[0028]

In order to achieve the above object, in the steam reformer according to claim 1 of the present invention, the steam reformer is arranged in an atmosphere in which a high temperature primary gas flows, and steam and hydrocarbon gas are introduced from one end. And a catalyst tube in which the secondary gas mixed with is supplied and the other end is closed, and the catalyst tube is inserted so that one end is located near the inner bottom of the catalyst tube and the other end is located outside the catalyst tube. In a steam reformer equipped with a flow path forming tube and a catalyst filled between the inner surface of the catalyst tube and the outer surface of the flow path forming tube, a flow of secondary gas is applied to the flow path forming tube. A heat transfer accelerating body is placed to bypass the heat transfer.

In the steam reformer according to claim 2 of the present invention, the steam reformer is arranged in an atmosphere in which a high temperature primary gas flows, and a secondary gas in which steam and a hydrocarbon gas are mixed is supplied from one end and the other end is supplied. A closed catalyst tube, a flow path forming tube inserted into the catalyst tube so that one end is located near the inner bottom of the catalyst tube and the other end is located outside the catalyst tube; and an inner surface of the catalyst tube. In the steam reformer provided with the catalyst filled between the outer surface of the flow path forming tube and the inner surface of the flow path forming tube, unevenness for bypassing the flow of the secondary gas is formed.

Further, in the steam reformer according to claim 3 of the present invention, the constituent requirements of the steam reformer according to claim 1 and the structure of the steam reformer according to claim 2 described above. In order to meet both requirements, a heat transfer promoter that diverts the flow of the secondary gas is arranged inside the flow passage forming pipe, and the flow of the secondary gas is diverted to the inner surface of the flow passage forming pipe. The unevenness is formed.

Further, in the steam reformer according to the fourth aspect of the present invention, the heat transfer promoting body is a rod-shaped body having irregularities on the surface.

In the steam reformer according to the first aspect of the present invention, the secondary fluid flowing through the inside of the flow passage forming pipe is diverted by the heat transfer promoter inserted in the flow passage forming pipe, The thermal energy of the secondary gas flowing through the inside of the catalyst pipe and the flow passage forming pipe is efficiently transmitted to the secondary gas flowing between the catalyst pipe and the flow passage forming pipe, so that the heat energy is passed between the catalyst pipe and the flow passage forming pipe. Increase the temperature of the secondary gas.

In the steam reformer according to the second aspect of the present invention, the secondary fluid flowing inside the flow passage forming pipe is diverted by the unevenness formed on the inner surface of the flow passage forming pipe, The thermal energy of the secondary gas flowing inside is efficiently transmitted to the secondary gas flowing between the catalyst pipe and the flow passage forming pipe, so that the heat energy flowing between the catalyst pipe and the flow passage forming pipe is increased. Increase the temperature of the secondary gas.

In the steam reformer according to the third aspect of the present invention, the heat transfer promoter in which the secondary fluid flowing inside the flow path forming tube is inserted and the inner surface of the flow path forming tube are provided. By bypassing the formed irregularities and efficiently transferring the thermal energy of the secondary gas flowing inside the flow passage forming pipe to the secondary gas flowing between the catalyst pipe and the flow passage forming pipe, the catalyst pipe The temperature of the secondary gas flowing between the channel and the flow path forming pipe is increased.

In the steam reformer according to the fourth aspect of the present invention, the heat transfer enhancement which is a rod-shaped body having irregularities on the surface in which the secondary fluid flowing inside the flow path forming tube is inserted into the flow path forming tube. By circumventing the body, the heat energy of the secondary gas flowing inside the flow passage forming pipe is efficiently transmitted to the secondary gas flowing between the catalyst pipe and the flow passage forming pipe, so that the flow of the catalyst pipe The temperature of the secondary gas flowing between the passage forming pipe and the passage forming pipe is increased.

[0036]

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

FIG. 1 is a longitudinal sectional view showing a first example of the embodiment of the steam reformer of the present invention. In the steam reformer shown in FIG. 1, the catalyst pipe 24 is described with reference to FIG. Like the conventional steam reformer, the inner cylinder 9 (not shown in FIG. 1) is arranged in an atmosphere in which a high temperature primary gas 28 such as helium (He) flows and the lower end is closed. ing.

A flow path forming tube 26 is inserted inside the catalyst tube 24, and a lower end of the flow path forming tube 26 is opened near a lower end of the catalyst tube 24, so that an outer surface of the flow path forming tube 26 is formed. A pellet-shaped catalyst 27 for producing hydrogen (H ₂ ) from steam (H ₂ O) and methane (CH ₄ ) is filled between the inner surface of the catalyst tube 24 and the catalyst tube 24.

A rod-shaped heat transfer enhancer 34 having a spiral convex portion 32 and a concave portion 33 formed on its peripheral surface is inserted into the axial center of the flow passage forming tube 26. The lower end of the heat transfer promoting body 34 is
The spiral convex portion 32 is fitted and supported in the fitting hole 35 of the support plate 37 having the fitting hole 35 and the flow hole 36 attached to the lower end of the flow path forming pipe 26, and the spiral convex portion 32 forms the flow path. It is in close proximity to the inside surface of the tube 26.

In the steam reformer shown in FIG. 1 described above, as in the conventional case, the secondary gas 29 in which steam (H ₂ O) and methane (CH ₄ ) are mixed is supplied from the upper end of the catalyst tube 24. . Then, the catalyst 27, which is filled between the inner surface of the catalyst tube 24 and the outer surface of the flow path forming tube 26, flows downward from above, and is transmitted from the primary gas 28 through the catalyst tube 24. Due to the heat energy and the catalyst 27, the water vapor (H ₂ O) contained in the secondary gas 29 and the methane (C
H ₄ ) reacts with each other to generate hydrogen (H ₂ ) and carbon monoxide (CO).
Is generated.

The post-reaction secondary gas 29 that has flowed through the inside of the catalyst 27 from the upper side to the lower side and has reached the lower end inside the catalyst tube 24 passes through the flow holes 36 of the support plate 37 and the flow path forming tube 2
It flows from the lower end of 6 into the flow path forming pipe 26.

Conventionally, the secondary gas 2 after the reaction that has flowed from the lower end of the flow path forming tube 26 into the flow path forming tube 26 is used.
9 flowed straight through the inside of the flow path forming pipe 26 from the lower side to the upper side and flowed out from the secondary fluid outlet pipe 19 (see FIG. 5) to the outside. Since the rod-shaped heat transfer accelerator 34 having the spiral convex portion 32 and the concave portion 33 formed on the circumferential surface is inserted into the axial center, the secondary heat-reacting secondary material that has flowed into the flow path forming tube 26 is reacted. Gas 29
The flow path forming pipe 26 while circumventing the concave portion 33 in a spiral shape
It will flow upwards inside.

The thermal energy of the reacted secondary gas 29 flowing upward in the flow path forming pipe 26 is retained by the reacted secondary gas 29.
By making a spiral detour in the inside of 6 and causing large turbulence in the inner wall surface of the flow path forming pipe 26, the secondary gas 29 in the reaction flowing in the inside of the catalyst 27 from the upper side to the lower side. , Is transmitted through the pipe wall of the flow passage forming pipe 26 with higher efficiency than before.

Therefore, the secondary gas after flowing through the inside of the catalyst 27 filled between the inner surface of the catalyst tube 24 and the outer surface of the flow path forming tube 26 from the upper side to the lower side and reacting In No. 29, the temperature becomes higher than in the past, more methane (CH ₄ ) reacts with steam (H ₂ O), more hydrogen (H ₂ ) is produced, and the remaining amount of methane (CH ₄ ) After flowing into the lower end of the flow passage forming pipe 26 in a small amount and flowing through the inside of the flow passage forming pipe 26 from the lower side to the upper side, the heat exchange is performed, and then the upper inner cylinder 17 similar to that in FIG. It flows out from the secondary fluid outlet pipe 19 to the outside through a fluid chamber 31 formed by the inner surface, the upper surface of the tube sheet 20 and the lower surface of the reformer lid 21.
More hydrogen (H ₂ ) will be collected than before.

FIG. 2 is a vertical sectional view showing a second example of the embodiment of the steam reformer of the present invention. The same parts as those in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted.

In the steam reformer shown in FIG. 2, a large number of recessed grooves 39 are juxtaposed on the circumferential surface of a rod-shaped heat transfer accelerator 38 inserted in the axial center of the flow path forming tube 26. .

In the steam reformer of FIG. 2, the secondary gas 29 after the reaction, which has flowed from the lower end of the flow passage forming pipe 26 into the flow passage forming pipe 26, flows into the groove 39 to disturb the flow. ,
It will flow upward inside the flow path forming pipe 26 while bypassing the groove 39.

The thermal energy possessed by the secondary gas 29 after the reaction is equal to that of the secondary gas 29 after the reaction.
Bypasses the inside of the flow passage forming pipe 26 and causes a large turbulence on the inner wall surface of the flow passage forming pipe 26, so that the secondary gas in the reaction that flows through the inside of the catalyst 27 from the upper side to the lower side. The secondary gas 29, which is transmitted to the catalyst 29 with high efficiency and flows through the inside of the catalyst 27 from the upper side to the lower side and reacts, has a high temperature and a large amount of hydrogen (H ₂ ) is generated.

FIG. 3 is a vertical sectional view showing a third example of the embodiment of the present invention. The same parts as those in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted.

In the steam reformer shown in FIG. 3, a large number of irregularities 40 are formed on the inner surface of the flow path forming pipe 26, and the irregularities 4 are formed.
By 0, the secondary gas 29 after the reaction that has flowed into the flow path forming pipe 26 is diverted to cause a large turbulence in the flow path wall surface, and flow upward in the flow path forming pipe 26. The unevenness 40 causes the secondary gas 29 after the reaction.
Works to bypass.

As a result, the secondary gas 29 after flowing through the inside of the catalyst 27 from the upper side to the lower side and reacting receives the thermal energy held by the secondary gas 29 after the reaction and has a high temperature. And a large amount of hydrogen (H ₂ ) is generated.

The unevenness 40 can be formed so as to be continuous in a spiral shape.

FIG. 4 is a vertical cross-sectional view showing a fourth example of the embodiment of the present invention. The same parts as those in FIGS. 2 and 3 are designated by the same reference numerals and the description thereof will be omitted.

In the steam reformer shown in FIG. 4, a large number of grooves 39 for forming irregularities are juxtaposed on the peripheral surface of the rod-shaped heat transfer promoting body 38 inserted in the axial center of the flow path forming tube 26. However, a large number of irregularities 40 are formed on the inner surface of the flow channel forming tube 26 so as to face the grooves 39 of the heat transfer promoting body 38. The grooves 39 and the irregularities 40 form the flow channel forming tube 26. The post-reaction secondary gas 29 that has flowed into the inside is diverted, and while flowing into the inside of the flow passage forming pipe 26 upward while causing a large turbulence on the inner wall surface of the flow passage forming pipe 26, The heat energy that is present is transferred with high efficiency to the secondary gas 29 during the reaction that flows from the upper side to the lower side inside the catalyst 27, and the secondary gas 29 after the reaction has a high temperature and a large amount of hydrogen. (H ₂ ) is generated.

The steam reformer of the present invention is not limited to the above-mentioned embodiment, and various modifications can be made without departing from the scope of the present invention.

[0056]

As described above, in any of the steam reformers described in claims 1 to 4 of the present invention, the secondary gas after the reaction is diverted inside the flow path forming pipe. However, while flowing upward, the heat energy held by the catalyst is transferred with high efficiency to the secondary gas during the reaction flowing from the upper side to the lower side inside the catalyst. The excellent effect of increasing the temperature of the secondary gas to generate a large amount of hydrogen can be obtained.

[Brief description of the drawings]

FIG. 1 is a vertical cross-sectional view showing a first example of an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view showing a second example of the embodiment of the present invention.

FIG. 3 is a vertical cross-sectional view showing a third example of the embodiment of the present invention.

FIG. 4 is a vertical cross-sectional view showing a fourth example of the embodiment of the present invention.

FIG. 5 is a vertical sectional view showing an example of a conventional steam reformer.

FIG. 6 is a graph showing the relationship between the secondary gas temperature after the reaction in the steam reformer and the residual amount of methane in the secondary gas.

[Explanation of symbols]

 24 catalyst pipe 26 flow path forming pipe 27 catalyst 28 primary gas 29 secondary gas 32 convex portion (unevenness) 33 concave portion (unevenness) 34 heat transfer promoting body 38 heat transfer promoting body 39 groove (unevenness) 40 unevenness

Claims (4)

[Claims] 1. A catalyst tube which is arranged in an atmosphere in which a high temperature primary gas flows and which is supplied with a secondary gas in which steam and a hydrocarbon gas are mixed from one end and whose other end is closed, and an inner bottom portion of the catalyst tube. A flow path forming tube inserted into the catalyst tube so that one end is located in the vicinity and the other end is located outside the catalyst tube, and the space is filled between the inner surface of the catalyst tube and the outer surface of the flow path forming tube. In the steam reformer provided with the above catalyst, a heat transfer accelerator for diverting the flow of the secondary gas is arranged in the flow path forming pipe. 2. A catalyst tube which is arranged in an atmosphere in which a high temperature primary gas flows and which is supplied with a secondary gas in which steam and a hydrocarbon gas are mixed from one end and whose other end is blocked, and an inner bottom portion of the catalyst tube. A flow path forming tube inserted into the catalyst tube so that one end is located in the vicinity and the other end is located outside the catalyst tube, and the space is filled between the inner surface of the catalyst tube and the outer surface of the flow path forming tube. In the steam reformer including the catalyst, the steam reformer is formed on the inner surface of the flow path forming pipe with irregularities that bypass the flow of the secondary gas. 3. A catalyst tube which is arranged in an atmosphere in which a high temperature primary gas flows and which is supplied with a secondary gas in which steam and a hydrocarbon gas are mixed from one end and whose other end is closed, and an inner bottom portion of the catalyst tube. A flow path forming tube inserted into the catalyst tube so that one end is located in the vicinity and the other end is located outside the catalyst tube, and the space is filled between the inner surface of the catalyst tube and the outer surface of the flow path forming tube. In the steam reformer equipped with the catalyst, a heat transfer promoting member that diverts the flow of the secondary gas is arranged inside the flow path forming pipe, and a secondary heat transfer accelerator is provided on the inner surface of the flow path forming pipe. A steam reformer, characterized in that it has irregularities for bypassing the flow of gas. 4. The steam reformer according to claim 1 or 3, wherein the heat transfer promoter is a rod-shaped body having irregularities on its surface.