JPH06345406A - Hydrogen production equipment - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide a hydrogen production device capable of producing high-purity hydrogen by collectively performing each reaction of a reformer, a carbon monoxide shift converter, and a hydrogen purifier. In an apparatus for producing hydrogen from hydrocarbons and / or alcohols by a steam reforming reaction, an upright burner 1, a cylindrical radiant plate 2 surrounding the burner and having an open upper end, and a constant distance from the radiant plate. A plurality of upright closed reaction tubes 3 which are annularly arranged on the outer periphery of the radiation plate and whose lower end communicates with the offgas exhaust port 3a, and a burner exhaust gas exhaust port 1a which covers the burner and the reaction tube in the lower part. And an upright raw material supply pipe 10 having an upper end opened inside the reaction pipe and a lower end communicating with the raw material supply port 10a, and an outer peripheral side surface of the raw material supply pipe and an open upper end. An upright hydrogen extraction pipe 11 whose lower end communicates with the hydrogen discharge port 11a, and an upright closed hydrogen permeation pipe 12 which surrounds the outer circumference of the hydrogen extraction pipe and whose upper end is closed and whose lower end communicates with the sweep gas supply port 12a. And the reforming catalyst 5 was filled between the hydrogen permeation tube and the reaction tube.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for steam reforming hydrocarbons and / or alcohols to produce hydrogen.

[0002]

2. Description of the Related Art A method for producing hydrogen in a reformer by utilizing a steam reforming reaction from hydrocarbons and / or alcohols is widely used industrially. On the other hand, in a fuel cell that operates at about 200 ° C. or lower, the catalyst such as platinum in the electrode is poisoned by CO, so the CO concentration in the hydrogen-containing gas supplied to the fuel cell must be 1% or lower. There is.
Fuel cells that operate at a relatively low temperature of 200 ° C. or less include phosphoric acid type that operates at 150 to 230 ° C., solid polymer membrane type that operates at 100 ° C. or less, and alkaline type, but especially at 100 ° C. or less. In the working solid polymer membrane type,
The CO concentration in the hydrogen-containing gas supplied to the fuel cell is 10 pp
It is said that it must be less than m. Therefore, in order to utilize the hydrogen produced by the conventional method as the fuel gas for the above-mentioned fuel cell, the crude hydrogen is further purified by a carbon monoxide shift converter and a hydrogen purifier to obtain high purity (about C
O of 10 ppm or less), it is considered to be used for a solid polymer membrane fuel cell (polymer fuel cell). The reaction that takes place in this case is as follows in the case of methane.

[0003]

However, the above-mentioned process for purifying hydrogen in high purity has complicated steps, the entire apparatus is large, and a large amount of high-temperature heat energy is required.
In addition, the efficiency of the device is low, and the hydrogen production cost is inevitably high. It is economical to produce high-purity hydrogen that is directly supplied from a city gas or the like to a solid polymer membrane fuel cell. It is extremely difficult to consider.

For this reason, the concept of a membrane reactor that simultaneously processes a reforming reaction and hydrogen purification by allowing a hydrogen separation membrane (membrane) that selectively permeates hydrogen to coexist in the reforming reaction field has already been proposed. No. 17401 and Japanese Patent Application No. 4-321502. However, in these prior applications, only the basic principle of the reactor is proposed, and a practical reactor configuration that can be easily increased in size, in particular, a heating method and a supply / discharge method of each fluid are not shown. That is, in these prior applications, as shown in FIG. 4, a hydrogen permeation tube that selectively permeates hydrogen is used as an inner tube, and a catalytic reaction tube is disposed as an outer tube in a concentric cylindrical shape outside the inner tube. It has only been shown to fill the annular space between the outer tubes with the reforming catalyst and to heat the outer tube walls with a suitable heating medium.

The present invention has been made in consideration of the above points, and the reactions of the reformer, the carbon monoxide shift converter and the hydrogen purifier used in the conventional process are collectively carried out,
An object of the present invention is to provide a so-called membrane reactor type highly practical hydrogen production apparatus capable of producing high-purity hydrogen.

[0006]

In order to solve the above-mentioned problems, the present invention relates to an apparatus for producing hydrogen from hydrocarbons and / or alcohols by a steam reforming reaction, in an upright burner and an upper end surrounding the burner. A cylindrical radiating plate having an opening, a plurality of upright cylindrical closed reaction tubes which are annularly arranged at an outer periphery of the radiating plate at a constant distance from the radiating plate and whose lower end communicates with a process-off gas outlet. A cylindrical closed case that covers the burner and the reaction tube and has a discharge port for combustion exhaust gas in the lower part, and the reaction tube has an upright cylindrical shape whose upper end opens inside the reaction tube and whose lower end communicates with the material supply port. A raw material supply pipe, an upright cylindrical hydrogen extraction pipe that surrounds the outer peripheral side surface of the raw material supply pipe and has an upper end that opens and a lower end that communicates with the hydrogen discharge port, and surrounds the outer periphery of the hydrogen extraction pipe and closes the upper end. lower end Enclosing an upstanding cylindrical hydrogen permeation tube leading to sweep gas supply port, characterized by being filled with reforming catalyst between the reaction tube and the hydrogen permeation tube.

[0007]

[Function] The hydrogen producing apparatus of the present invention includes a reforming catalyst, a hydrogen permeation tube (such as a thin film formed of palladium or a palladium alloy),
It is a hydrogen permeable membrane type reformer composed of a heating burner and the like, and can produce high-purity hydrogen directly from hydrocarbons and / or alcohols. That is, high-purity hydrogen can be easily obtained by penetrating the catalyst layer in the reaction tube and providing the hydrogen permeation tube. By providing a burner in the center and providing a radiant plate around the burner, the radiant heat is efficiently and evenly transmitted to a plurality of reaction tubes around the radiant plate, and the high-temperature combustion exhaust gas of the burner is located above each reaction tube. It pours down from the surroundings and transfers convective heat and conductive heat to each reaction tube evenly. The sweep gas is supplied as an upward flow and becomes a counter flow to the downward flow of gas in the catalyst layer, so that hydrogen permeation is efficiently performed. Further, since the chemical equilibrium is shifted by using the hydrogen permeation tube, the reforming temperature (700 to 800 ° C) is set to 150 to
It can be lowered by 200 ° C.

[0008]

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

FIG. 1 is a vertical cross-sectional view showing a schematic structure of the hydrogen production apparatus of the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG.

In FIGS. 1 and 2, an upright cylindrical burner which burns fuel such as city gas or natural gas blown from the central hole of the bottom burner tile 7 constructed of an annular refractory material to generate high temperature combustion exhaust gas. 1 is provided at the center of the hydrogen production device. The hydrogen production apparatus in the figure is shown with auxiliary equipment, heat insulating material layer, and protective cover material attached to the outer periphery thereof removed.

A cylindrical radiant plate 2 is provided around the burner 1 around the burner 1, and the high-temperature combustion exhaust gas of the burner 1 gives radiant heat to the radiant plate 2 and outward from the upper opening of the radiant plate 2. It is configured to flow in the direction of arrow D.

A plurality of (8 in the embodiment of FIG. 2) are provided on the outer periphery of the radiation plate 2 with a certain gap from the radiation plate 2.
Reaction tubes 3 are annularly arranged at equal intervals.

The case 4 is hermetically covered from above and on all sides of the burner 1 and the reaction tube 3 with a gap therebetween. The high-temperature combustion exhaust gas generated by the burner flows into the gap, and is further poured from the top of each reaction tube 3 and flows around them. The closed case 4 is provided with a discharge port 1a at its lower part, through which used combustion exhaust gas is discharged in the direction of arrow D.

FIG. 3 is an enlarged view of a part of FIG. 1, and is a vertical sectional view showing a detailed structure of the reaction tube 3.

In FIG. 3, the reaction tube 3 is an upright cylindrical closed tank, the ceiling is closed, and the lower end communicates with the process-off gas discharge port 3a. Inside the reaction tube 3,
Raw material supply pipe 10 as the center and hydrogen extraction pipe 1 outside thereof
1 and a hydrogen permeation tube 12 on the outer side thereof.
These tubes 10, 11 and 12 are arranged upright in a concentric multi-cylindrical manner with a radial spacing from each other. As the hydrogen permeation tube 12, a material which can selectively permeate hydrogen and has heat resistance of 500 to 600 ° C., such as one prepared by forming palladium on a porous carrier by an electroless plating method, can be used. The other components are mainly made of stainless steel.

The raw material supply pipe 10 has an upper end open to the inside of the reaction tube 3 and a lower end communicating with the raw material supply port 10a. The hydrogen extraction pipe 11 surrounds the outer circumference of the raw material supply pipe 10, the upper end opens inside the hydrogen permeation pipe 12, and the lower end opens the hydrogen discharge port 11.
It communicates with a. The hydrogen permeation pipe 12 encloses the outer periphery and the ceiling of the hydrogen extraction pipe 11 in a hermetically sealed manner with a gap therebetween, and the lower end communicates with the sweep gas supply port 12a.

City gas and water vapor used as raw materials are manifold 6
Is blown upward from a hole in the lower center of the hydrogen producing apparatus, and the sweep gas is blown upward from the manifold 6 from an annular inlet in the lower center of the apparatus. Similarly, a mixture of hydrogen and sweep gas and process off-gas is discharged from the respective manifold outlets at the center of the lower part of the apparatus to the manifold 6
It has a structure to be discharged through.

Combustion exhaust gas discharge port 1a of case 4, process off gas discharge port 3a of reaction tube 3, sweep gas supply port 12a of hydrogen permeation tube 12, hydrogen discharge port 11a of hydrogen extraction tube 11, raw material supply of raw material supply tube 10 All the mouths 10a are put together in the manifold 6. The process off gas is a residual gas obtained by permeating and removing hydrogen from the generated gas, and the sweep gas is a gas for scavenging the hydrogen generated in the hydrogen permeation pipe 12.

The space between the hydrogen permeation tube 12 and each reaction tube 3 is filled with the reforming catalyst 5. As the reforming catalyst, a catalyst containing a Group VIII metal (Fe, Co, Ni, Ru, Rh, Pd, Pt, etc.) is preferable, and a catalyst supporting Ni, Ru, Rh or a NiO-containing catalyst is particularly preferable.

The hydrogen production device of the present invention having the above-mentioned structure operates as follows.

Combustion of fuel supplied from below by the burner 1 produces high temperature combustion exhaust gas. The combustion exhaust gas flows in the direction of arrow D from the upper peripheral edge of the radiant plate 2 around the burner 1 into the inside of the case 4, falls from above each reaction tube 3, and further flows between the radiant plate 2 and the case 4. Then, heat is transferred to each reaction tube 3 by convection and conduction heat transfer. At the same time, the combustion heat of the burner 1 evenly transfers the radiant heat to the respective reaction tubes 3 around it through the radiant plate 2. Thus, the reforming catalyst 5 and the reforming gas as the reaction fluid in each reaction tube 3 are heated.

The sweep gas is sent from the supply port 12a to the hydrogen permeable pipe 12 in the direction of arrow B.

A mixture of methane or the like and steam as a raw material gas is fed from the supply port 10a in the direction of the arrow A, and penetrates through the raw material supply pipe 10 into the inside of the reforming catalyst 5 of each reaction tube 3 from above. While the raw material gas passes through the inside of the reforming catalyst 5, the raw material gas such as methane is steam-reformed with the heat generated by the combustion of the fuel gas to generate hydrogen. The reaction formula at this time is as follows, when an example of methane is shown.

The generated hydrogen permeates into the hydrogen permeation tube 12 in the direction of arrow C, and rises in the direction of arrow B along with the sweep gas, and then advances through the hydrogen extraction tube 11 in the direction of arrow E and is discharged. It is pushed out from the outlet 11a in the direction of arrow E.

Further, the off gas such as carbon dioxide gas in the reaction tube 3 is discharged from the discharge port 3a to the outside in the direction of arrow F. At this time, the discharge direction (downward) of the off gas in the packed bed of the reforming catalyst 5 is opposite to the inflow direction (upward) of the sweep gas in the hydrogen permeation tube 12, so the packed bed of the reforming catalyst 5 is Hydrogen permeation pipe for hydrogen from reformed gas flowing inside 1
2 can be efficiently transmitted.

It is possible to increase or decrease the number of the annular rows of the reaction tubes 3 used in the apparatus of the above-mentioned embodiment, or to increase or decrease the number of the reaction tubes 3 in one annular row.

The apparatus of the above-mentioned embodiment is inverted so that fuel is blown into the burner from above for combustion, and sweep gas, raw material gas and steam are introduced from above and hydrogen and off-gas are discharged from above. You can also

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments of the present invention will be described below. (1) Equipment configuration Reaction tube 3 (inner diameter 35.5 mm) Hydrogen permeation tube 12 (outer diameter 20 mm) Hydrogen extraction tube 11 (outer diameter 12 mm) Raw material supply pipe 10 (outer diameter 6 mm) Effective length 1000 mm
The reaction tube structure of multiple concentric cylinders was constructed, and a total of 24 of these were arranged upright on the outer peripheral side inside the case 4 at equal intervals in the circumferential direction. Case 4 has an outer diameter of 350 mm and an effective height of 1
450 mm, and the radiation plate 2 inside is 100 mm outside diameter x
The effective height is 1000 mm. The hydrogen permeation tube 12 was a membrane made of a palladium-based thin film, and the reforming catalyst 5 was a nickel-based catalyst (average particle diameter 2 mmφ). (2) Operating conditions-Source gas supply: methane 1.4 Nm ³ / h-Reforming steam supply: 4.2 Nm ³ / h (steam / methane molar ratio S / C = 3.1) -Sweep gas (Steam) supply rate: 5.6 kg / h ・ Sweep gas pressure: atmospheric pressure ・ Catalyst layer temperature: 533 to 537 ° C ・ Catalyst layer pressure: 6.2 kg / cm ² -abs. The bed temperature was adjusted to the above value. (3) Hydrogen production test result Under the above operating conditions, the amount of hydrogen obtained by entraining methane 1.16 Nm ³ / h in the sweep gas was 3.8 Nm ³ / h, and impurities in hydrogen were found. CO as
Was 1 ppm or less. A reaction conversion rate of methane of about 80% was achieved. In a conventional reformer that does not employ a hydrogen permeation tube, the conversion rate is 25% due to the chemical equilibrium wall due to the relationship between operating temperature and pressure.

[0030]

As described above, according to the present invention, the following excellent effects can be obtained. (1) High-purity hydrogen can be directly produced from hydrocarbons and / or alcohols. (2) The burner, radiant plate, raw material supply pipe, reaction pipe, reforming catalyst layer, hydrogen permeation pipe, hydrogen extraction pipe, and case are efficiently arranged, heat transfer is improved, and generated heat energy is effectively used. The energy saving process is realized, the hydrogen production capacity is improved, and the structure of the entire device is simplified and becomes compact. (3) Since the furnace is provided in the central portion, the heat transfer rate in the radial direction due to radiation is increased, and the heat flux distribution is easily made uniform. Therefore, it is possible to prevent the occurrence of hot spots that exceed the heat resistant temperatures of the hydrogen permeation tube and the reforming catalyst. (4) Since the sweep gas flowing in the hydrogen permeable pipe and the reformed gas flowing in the reforming catalyst layer are mass-transferred by countercurrent contact through the hydrogen permeable pipe wall, It is possible to increase the recovery rate and increase the hydrogen concentration in the permeated gas. (5) The separation and purification steps after the reaction are omitted. (6) The chemical equilibrium is shifted by the hydrogen permeation tube, the reforming temperature is lowered by 150 to 200 ° C compared with the conventional method, the selection range of materials used for manufacturing the device is expanded, the cost is reduced, and the durability of the device is improved. Let

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing a schematic configuration of a hydrogen production device of the present invention.

FIG. 2 is a sectional view taken along the line II-II in FIG.

FIG. 3 is an enlarged view of a part of FIG. 1, showing a detailed structure inside the reaction tube.

FIG. 4 is a diagram showing the principle of a membrane reactor type hydrogen production apparatus proposed so far.

[Explanation of symbols]

 1 Burner 1a Combustion exhaust gas discharge port 2 Radiant plate 3 Reaction tube 3a Process off gas discharge port 4 Case 5 Reforming catalyst 6 Manifold 7 Bottom burner tile 10 Raw material supply pipe 10a Raw material supply port 11 Hydrogen extraction pipe 11a Hydrogen discharge port 12 Hydrogen permeation pipe 12a Sweep gas supply port

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroshi Uchida 3-2-15-106 Azamino, Midori-ku, Yokohama, Kanagawa Prefecture (72) Kennosuke Kuroda 15-1 Tomihisacho, Shinjuku-ku, Tokyo Mitsubishi Heavy Industries Engineering Co., Ltd. Inside the center (72) Inventor Toshiyuki Uchida 4-6-22 Kannon Shinmachi, Nishi-ku, Hiroshima City, Hiroshima Prefecture Sanryoh Heavy Industries Ltd. Hiroshima Works (72) Inventor Kazuto Kobayashi 4-6-22 Kannon Shinmachi, Nishi-ku, Hiroshima City, Hiroshima Prefecture Hishi Heavy Industries Ltd. Hiroshima Research Center

Claims (1)

[Claims] 1. An apparatus for producing hydrogen from a hydrocarbon and / or alcohol by a steam reforming reaction,
An upright burner, a cylindrical radiating plate surrounding the burner and having an open upper end, and a plurality of circular radiating plates arranged at an outer periphery of the radiating plate at a constant interval from the radiating plate and having a lower end communicating with a process-off gas outlet. A vertical closed cylindrical reaction tube, and a cylindrical closed case that covers the burner and the reaction tube and has a discharge port for combustion exhaust gas in the lower part, and the reaction tube has an upper end opening inside the reaction tube. An upright cylindrical raw material supply pipe whose lower end communicates with the raw material gas supply port, an upright cylindrical hydrogen extraction pipe surrounding the outer peripheral side surface of the raw material supply pipe and having an upper end opened and a lower end communicating with the hydrogen discharge port, and the hydrogen. An upright cylindrical hydrogen permeation tube surrounding the outer circumference of the take-out tube and having the upper end closed and the lower end communicating with the sweep gas supply port was included, and a reforming catalyst was filled between the hydrogen permeation tube and the reaction tube. A hydrogen production device characterized by the above.