JP2005089209A - Reforming equipment, and fuel cell system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To uniformly feed a gaseous starting material into a reforming reaction region by a simple constitution reducing the required space in reforming equipment, and to attain miniaturizing, lightening, increase of performance and elongation of the service life in a fuel cell system comprising the reforming equipment. <P>SOLUTION: In the reforming equipment comprising a reforming reaction tube provided with a catalytic layer for producing a hydrogen-containing gas by reforming the raw material for producing hydrogen, a pressure loss generating means for generating pressure loss in the reforming reaction tube is provided. In the fuel cell system equipped with reforming equipment comprising a reforming reaction tube provided with a catalytic layer for producing a hydrogen-containing gas by reforming the raw material for producing hydrogen, and a fuel cell using a hydrogen-containing gas as fuel, the reforming equipment is provided with a pressure loss generating means for generating pressure loss in the reforming reaction tube. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a reformer for producing hydrogen by reforming raw materials such as kerosene. In particular, the present invention relates to a reformer that can be suitably used in a fuel cell system. The present invention also relates to a fuel cell system having such a reformer.

  Development of fuel cells has been actively promoted as a power generation system with high energy utilization efficiency. Among them, the polymer electrolyte fuel cell is particularly attracting attention because of its high power density and ease of handling.

  Since a fuel cell generates power by an electrochemical reaction between hydrogen and oxygen, it is essential to establish a hydrogen supply means. As one of the methods, there is a method of producing hydrogen by reforming a raw material for hydrogen production such as a hydrocarbon fuel, and a method using pure hydrogen in that a hydrocarbon fuel supply system has already been socially established. More advantageous.

  Examples of the hydrocarbon fuel include city gas, gasoline, kerosene, and light oil. Liquid fuels such as gasoline, kerosene, and light oil are attracting attention as fuel cells because they are easy to handle, store and transport, and are inexpensive. In order to use these hydrocarbon fuels in fuel cells, it is necessary to produce hydrogen from hydrocarbons. For this purpose, hydrocarbons are reacted with water in a reformer, mainly into carbon monoxide and hydrogen. In the shift reactor, where most of the carbon monoxide reacts with water to convert it to hydrogen and carbon dioxide, and finally in the selective oxidation reactor, a small amount of residual carbon monoxide reacts with oxygen to form carbon dioxide. Things have been done. Further, since sulfur becomes a poisoning substance such as a reforming catalyst, a desulfurizer for removing sulfur in the hydrocarbon fuel is often provided.

  As a reformer used for a fuel cell, Patent Document 1 discloses a reformer having a plurality of reforming reaction tubes (catalyst tubes).

A fuel cell system having a reformer is disclosed in, for example, Patent Document 2.
Special table 2002-529895 gazette JP 2003-187832 A

  In the reformer, it is important to manage the temperature distribution in the reaction zone. This is because if the reaction temperature is too low, the conversion rate decreases, and if the reaction temperature is too high, the catalyst and the reaction tube may be damaged. It is required to suppress the occurrence of so-called cold spots and hot spots as much as possible. However, the reforming reaction has a large reaction heat. For example, the steam reforming reaction involves intense endotherm, and the combustion reaction in the burner section for supplying reaction heat to the steam reforming reaction involves intense acid heat generation. For this reason, in the reformer, the temperature distribution in the reaction region tends to be steep, and its management is difficult compared to a shift reactor or the like.

  In order to satisfactorily manage the temperature distribution, it is desired to supply the raw material gas as uniformly as possible to the reforming catalyst layer as the reaction region. When a plurality of reaction tubes are provided in parallel, it is desired that the amount of gas supplied to each reaction tube be uniform. These are also desired from the viewpoint of efficiently using the catalyst layer without causing a dead zone in the catalyst layer. However, a reformer for a fuel cell system has a strong demand for miniaturization and weight reduction, and it is desirable to avoid taking a large space or using a large member for improving gas distribution. It is rare.

  In addition, even if the same amount of the same catalyst is filled in the same reaction tube, there may be a difference in the pressure loss of the catalyst layer depending on the filling state of the catalyst. For example, when a plurality of reforming reaction tubes are provided in parallel, It was difficult to make the amount of gas supplied to each reaction tube uniform.

  Therefore, it is desirable to supply the raw material gas uniformly to the reaction region of the reformer by using a configuration that is as simple and space-saving as possible, and that suppresses the influence of variations in pressure loss of the catalyst layer.

  An object of the present invention is to enable uniform supply of a raw material gas to a reforming reaction region with a simple and space-saving configuration in a reformer. Another object of the present invention is to achieve a reduction in size, weight, performance, and life in a fuel cell system having a reformer.

According to the present invention, in a reformer having a reforming reaction tube having a catalyst layer for producing a hydrogen-containing gas containing hydrogen by reforming a raw material for hydrogen production,
There is provided a reformer comprising pressure loss generating means for generating a pressure loss in the reforming reaction tube.

  This reformer is preferred for use in a fuel cell system.

  The reformer preferably includes a plurality of the reforming reaction tubes, and each reforming reaction tube includes an orifice as the pressure loss generating means.

  In this reformer, the pressure loss under the rated operating condition of the orifice provided in each reforming reaction tube is more than twice the average value of the pressure loss under the rated operating condition of the catalyst layer provided in each reforming reaction tube, and 10 times. The following is preferable.

  In addition, the cross-sectional area of the orifice provided in each reforming reaction tube is preferably 1 / 10,000 or more and 1/4 or less of the cross-sectional area in the flow path direction of the reforming reaction tube.

  In the reformer, it is preferable that a cross section in the flow direction of the reforming reaction tube is annular, and the reforming reaction tube is provided with an annular dispersion plate as the pressure loss generating means.

According to the present invention, a reformer having a reforming reaction tube having a catalyst layer for reforming a raw material for producing hydrogen to produce a hydrogen-containing gas containing hydrogen, and a fuel using the hydrogen-containing gas as a fuel In a fuel cell system comprising a battery,
A fuel cell system is provided in which the reformer includes pressure loss generating means for generating a pressure loss in the reforming reaction tube.

  According to the present invention, in a reformer for reforming a raw material for hydrogen production to obtain a hydrogen-containing gas containing hydrogen, a uniform gas supply to the reforming reaction region is achieved with a simple and small configuration. The property can be made excellent. Further, in a reformer having a plurality of reforming reaction tubes, the uniformity of gas supply to each reaction tube can be made excellent.

  As a result, the catalyst layer can be used efficiently, and the reformer can be reduced in size and weight. Also, the reaction temperature distribution can be easily managed, the conversion rate can be prevented from being lowered, and the life of the catalyst and the reaction tube can be extended. Furthermore, in a reformer having a plurality of reforming reaction tubes, the temperature distribution for each tube can be reduced.

  A fuel cell system equipped with such a reformer is small and lightweight, and can exhibit high performance over a long period of time.

  As the pressure loss generating means, any means can be used as long as the pressure loss is generated in the flow in the reaction tube, but an orifice or a dispersion plate is preferably used from the viewpoint of compactness and manufacturability.

  FIG. 1 is a schematic cross-sectional view showing a schematic configuration of a reaction tube array for one form of a reformer in which a plurality of reforming reaction tubes are arranged in parallel.

  A supply gas, for example, a mixed gas of hydrogen production raw material and steam is supplied to the reformer from the gas supply port 1, distributed in the inlet side manifold 2, and flows into the plurality of reforming reaction tubes 3. Each reaction tube 3 is filled with a catalyst to form a catalyst layer 4. The supply gas is reformed in the catalyst layer to become a reformed gas containing hydrogen, merges in the outlet side manifold 7 through the orifice 6, and flows out from the discharge port 8.

  Here, the reforming reaction tube is a circular tube, and the orifice plate 5 is an annular plate provided with one circular through hole (orifice 6) in the center. An orifice plate is provided in each reforming reaction tube so as to cover the flow path of the reforming reaction tube, and the gas flow path flowing through the reaction tube is once narrowed by the orifice plate and then expanded toward the manifold. Where pressure loss occurs. The shape (including dimensions) of each reforming reaction tube is the same, the shape (including dimensions) of each orifice plate is also the same, and each reforming reaction tube is filled with the same amount of the same catalyst.

  Orifice plates can be machined easily and precisely, so it is easy to produce a large number of orifice plates with almost the same pressure loss under certain conditions. Further, the orifice plate can be a thin plate, and the required space can be made very small.

  By providing each reforming reaction tube with an orifice having the same shape with high accuracy, the gas flow distribution to each reforming reaction tube becomes more uniform without being controlled by the pressure loss of the catalyst layer.

  From the viewpoint of suppressing the influence of the pressure loss of the catalyst layer, the pressure loss of the orifice is preferably 2 times or more, more preferably 3 times or more, more preferably 3 times or more of the pressure loss of the catalyst layer (average value of the pressure loss of each catalyst layer). 4 times or more. On the other hand, from the viewpoint of suppressing energy loss, the pressure loss of the orifice is preferably 10 times or less, more preferably 8 times or less, and further preferably 6 times or less. These pressure losses are values under rated operating conditions.

  Although depending on the form of the catalyst layer, from the viewpoint of suppressing energy loss, the cross-sectional area (So) of the orifice is preferably 1 / 10,000 or more, more preferably 1/900 or more, of the cross-sectional area (Sr) of the reforming reaction tube, 1/400 or more is more preferable. On the other hand, from the viewpoint of suppressing the influence of the pressure loss of the catalyst layer, the cross-sectional area ratio So / Sr is preferably 1/4 or less, more preferably 1/9 or less, and further preferably 1/25 or less.

  The shape of the reforming reaction tube and the shape of the orifice can be appropriately selected from known shapes, but the reforming reaction tube has a circular cross section in the flow passage direction from the viewpoints of manufacturability and strength, that is, a circular tube. It is preferable that the orifice has a circular cross section. In this case, the diameter of the orifice is preferably 1/100 or more, more preferably 1/30 or more, and further preferably 1/20 or more of the diameter of the reforming reaction tube from the viewpoint of suppressing the influence of pressure loss of the catalyst layer. Is done. On the other hand, from the viewpoint of suppressing energy loss, it is preferably 1/2 or less, more preferably 1/3 or less, and further preferably 1/5 or less of the diameter of the reforming reaction tube.

  In addition, from the viewpoint of the uniformity of gas flow distribution to each reforming reaction tube, the pressure loss variation of each orifice is the maximum differential pressure and the minimum differential pressure of the reforming tube expressed by the following formulas under the rated operating conditions. It is preferable that the ratio route is 1.03 or less (the differential pressure of the reforming tube in this case includes the differential pressure of the catalyst layer and the orifice).

これが実現されるような精度でオリフィスを製造すればよい。

The orifice may be manufactured with such an accuracy that this can be realized.

  In the above embodiment, the orifice is provided downstream of the catalyst layer. However, the orifice may be provided in the flow path of each reaction tube. For example, the orifice may be provided upstream of the catalyst layer.

  Here, the gas flow is an upflow, but it may be a downflow.

  In FIG. 1, the reforming reaction tubes are illustrated as being arranged in parallel on one plane. A form in which the reforming reaction tubes are arranged in parallel on one plane is also possible, but the reforming reaction tubes 3 can also be arranged on the circumference (indicated by a virtual line 30) as shown in FIG. The cross sections of the manifolds 2 and 7 can be annular (concentric with the circumference 30). In this case, a burner 32 is provided along the central axis of the reforming reaction tube array, and heat necessary for the steam reforming reaction can be supplied from the outside of the reforming reaction tube to the catalyst layer 4 by this burner. The reforming reaction tube, manifold, and burner are stored in a container 31 that can be sealed. The burner is supplied with combustion fuel from the combustion fuel supply pipe 33 and air as oxygen-containing gas from the combustion air supply pipe 34. The combustion gas is discharged from the combustion gas discharge pipe 35. A gas necessary for reforming is supplied from the gas supply pipe 1, and the obtained reformed gas is discharged from the reformed gas discharge port 8. 2A is a top view of the reformer of this embodiment, and FIG. 2B is a side sectional view.

  Next, another embodiment of the present invention will be described with reference to FIG. 3A is a side sectional view of the reforming reaction tube, and FIG. 3B is a view taken along the arrow A-A ′. The reforming reaction tube 13 shown here has an annular column shape in cross section, and can be manufactured by closing the end of the double tube. An annular dispersion plate 15 having a through hole 16 defines the reforming reaction tube. The lower area in the drawing of the dispersion plate is a space that functions as a manifold (hereinafter referred to as a manifold area 12). In the upper region of the dispersion plate in the drawing, voids 19 and 17 are provided at the top and bottom in the drawing, and the catalyst layer 14 having an annular cross section is formed.

  The gas supplied from the gas supply port 11 flows through the manifold region 12 from the hole 16 of the dispersion plate into the gap 19 and then into the catalyst layer 14. A reforming reaction occurs in the catalyst layer, and the reformed gas is discharged from the discharge port 18 through the gap 17.

  At this time, the uniformity of gas supply to the catalyst layer is improved by the effect of the pressure loss of the dispersion plate. The dispersion plate is a plate-like member provided with a plurality of through holes, and FIG. 3 shows a total of 8 holes. Depending on the desired gas flow uniformity, the diameter and number of through holes are as follows. The arrangement can be adjusted.

  The dispersion plate may be installed on the upstream side or the downstream side of the catalyst layer, but the downstream side is preferable from the viewpoint of making the flow uniform.

  In the case of this form as well, the burner is provided along the central axis of the reaction tube as in the case of the above-described form, whereby heat necessary for the steam reforming reaction can be supplied to the catalyst layer. In addition, the reaction tube and burner are housed in a sealable container, and a gas supply port required for the reforming reaction, a gas supply port required for burner combustion, a reformed gas discharge port, a combustion gas discharge port, etc. are provided. Thus, a reformer can be configured.

  The reformer is an apparatus for producing a reformed gas containing hydrogen by reacting a raw material for hydrogen production with water and / or oxygen. In this apparatus, the raw material for hydrogen production is mainly decomposed into hydrogen and carbon monoxide. Usually, carbon dioxide and methane are also contained in the cracked gas. Examples of the decomposition reaction include a steam reforming reaction, an autothermal reforming reaction, and a partial oxidation reaction.

The steam reforming reaction is a reaction between steam and hydrocarbon, but usually involves heating from the outside because it involves a large endotherm. Usually, the reaction is carried out in the presence of a metal catalyst typified by a Group VIII metal such as nickel, cobalt, iron, ruthenium, rhodium, iridium and platinum. The reaction temperature can be 450 ° C to 900 ° C, preferably 500 ° C to 850 ° C, more preferably 550 ° C to 800 ° C. The amount of steam introduced into the reaction system is defined as the ratio of the number of moles of water molecules to the number of moles of carbon atoms contained in the raw material for hydrogen production (steam / carbon ratio), and this value is preferably 0.5-10. Preferably it is 1-7, More preferably, it is 2-5. When the raw material for hydrogen production is liquid, the space velocity (LHSV) at this time is A / B when the flow rate in the liquid state of the raw material for hydrogen production is A (L / h) and the volume of the catalyst layer is B (L). This value is preferably set in the range of 0.05 to 20 h ⁻¹ , more preferably 0.1 to 10 h ⁻¹ , and still more preferably 0.2 to 5 h ⁻¹ .
Autothermal reforming reaction is a method of reforming while balancing the reaction heat by advancing the steam reforming reaction with the heat generated at this time while oxidizing part of the raw material for hydrogen production, Since it has a relatively short start-up time and is easy to control, it has recently attracted attention as a hydrogen production method for fuel cells. Also in this case, the reaction is usually carried out in the presence of a metal catalyst, typically a Group VIII metal such as nickel, cobalt, iron, ruthenium, rhodium, iridium and platinum. The amount of steam introduced into the reaction system is preferably 0.3 to 10, more preferably 0.5 to 5, and still more preferably 1 to 3 as a steam / carbon ratio.

  In autothermal reforming, oxygen is added to the raw material in addition to steam. The oxygen source may be pure oxygen, but in many cases air is used. Usually, oxygen is added to such an extent that it can generate an amount of heat that can balance the endothermic reaction associated with the steam reforming reaction, but the amount of addition is appropriately determined in relation to heat loss and external heating installed as necessary. The amount is preferably from 0.05 to 1, more preferably from 0.1 to 0.75, even more preferably as the ratio of the number of moles of oxygen molecules to the number of moles of carbon atoms contained in the raw material for hydrogen production (oxygen / carbon ratio). Is set to 0.2 to 0.6. The reaction temperature of the autothermal reforming reaction is set in the range of 450 ° C. to 900 ° C., preferably 500 ° C. to 850 ° C., more preferably 550 ° C. to 800 ° C., as in the case of the steam reforming reaction. When the raw material for hydrogen production is liquid, the space velocity (LHSV) at this time is preferably selected in the range of 0.1 to 30, more preferably 0.5 to 20, and still more preferably 1 to 10.

  The partial oxidation reaction is a method in which a reforming reaction is advanced by oxidizing a raw material for hydrogen production, and it has attracted attention as a hydrogen production method because it has a relatively short start-up time and can be designed compactly. The catalyst may or may not be used, but when the catalyst is used, a metal catalyst or a perovskite, typically a Group VIII metal such as nickel, cobalt, iron, ruthenium, rhodium, iridium, platinum, etc. The reaction is carried out in the presence of a spinel oxide catalyst. Steam can be introduced in order to suppress the generation of soot in the reaction system, and the amount thereof is preferably 0.1 to 5, more preferably 0.1 to 3, more preferably 1 to 2 as the steam / carbon ratio. It is said.

  In partial oxidation reforming, oxygen is added to the raw material. The oxygen source may be pure oxygen, but in many cases air is used. In order to secure a temperature for proceeding the reaction, the amount added is appropriately determined in terms of heat loss and the like. The amount is preferably 0.1 to 3, more preferably 0.2 to 0.7 as the ratio of the number of moles of oxygen molecules to the number of moles of carbon atoms contained in the raw material for hydrogen production (oxygen / carbon ratio). . The reaction temperature of the partial oxidation reaction can be in the range of 1,000 to 1,300 ° C. when a catalyst is not used, and when a catalyst is used, the reaction temperature is 450 as in the case of the steam reforming reaction. It can be set in the range of from 550C to 900C, preferably from 500C to 850C, and more preferably from 550C to 800C. When the raw material for hydrogen production is liquid, the space velocity (LHSV) at this time is preferably selected in the range of 0.1-30.

[CO shift reactor]
Although the hydrogen-containing gas produced by the reformer may be supplied to the fuel cell with the same composition, for example, the performance of a solid polymer fuel cell may be deteriorated by carbon monoxide. In the fuel cell system, it is preferable to provide a CO shift reactor downstream of the reformer.

  The gas generated in the reformer contains carbon monoxide, carbon dioxide, methane, and water vapor in addition to hydrogen. Further, nitrogen is also contained when air is used as an oxygen source in the autothermal reforming. Among these, the CO conversion reactor performs the step of reacting carbon monoxide with water to convert it into hydrogen and carbon dioxide. Usually, the reaction proceeds in the presence of a catalyst, and a catalyst containing a noble metal such as a mixed oxide of Fe—Cr, a mixed oxide of Zn—Cu, platinum, ruthenium, and iridium is used. Mol%) is preferably reduced to 2% or less, more preferably 1% or less, and even more preferably 0.5% or less. The shift reaction can also be carried out in two stages, in which case a high temperature CO shift reactor and a low temperature CO shift reactor are used.

[Selective oxidation reactor]
In the polymer electrolyte fuel cell system, it is preferable to further reduce the carbon monoxide concentration. For this purpose, it is preferable to treat the outlet gas of the CO shift reactor by a selective oxidation reaction. In this step, a catalyst containing iron, cobalt, nickel, ruthenium, rhodium, palladium, osmium, iridium, platinum, copper, silver, gold, etc. is used, preferably 0.5 to the number of moles of carbon monoxide remaining. The carbon monoxide concentration is preferably increased by selectively converting carbon monoxide to carbon dioxide by adding 10 moles, more preferably 0.7-5 moles, and even more preferably 1-3 moles of oxygen. Is reduced to 10 ppm (on a molar basis of the dry base) or less. In this case, the carbon monoxide concentration can be reduced by reacting with the coexisting hydrogen simultaneously with the oxidation of carbon monoxide to generate methane.

〔Fuel cell〕
As the fuel cell, a fuel cell of a type in which hydrogen is a reactant of the electrode reaction in the fuel electrode can be appropriately employed. For example, a fuel cell of a solid polymer type, a phosphoric acid type, a molten carbonate type, or a solid oxide type can be employed. Hereinafter, the configuration of the polymer electrolyte fuel cell will be described.

  The fuel cell electrode consists of an anode (fuel electrode) and cathode (air electrode) and a solid polymer electrolyte sandwiched between them. A hydrogen-containing gas is required on the anode side, and an oxygen-containing gas such as air is required on the cathode side. If so, it is introduced after appropriate humidification treatment.

  At this time, a reaction in which hydrogen gas becomes protons and emits electrons proceeds at the anode, and a reaction in which oxygen gas obtains electrons and protons to become water proceeds at the cathode. In order to promote these reactions, platinum black and Pt catalyst or Pt-Ru alloy catalyst supported on activated carbon are used for the anode, and platinum black and Pt catalyst supported on activated carbon are used for the cathode. Usually, both the anode and cathode catalysts are formed into a porous catalyst layer together with Teflon, a low molecular weight polymer electrolyte membrane material, activated carbon or the like as necessary.

  As solid polymer electrolytes, Nafion (Nafion, manufactured by DuPont), Gore (Gore, manufactured by Gore), Flemion (Flemion, manufactured by Asahi Glass), Aciplex (Aciplex, manufactured by Asahi Kasei), etc. A molecular electrolyte membrane is usually used, and the porous catalyst layer is laminated on both sides thereof to form an MEA (Membrane Electrode Assembly). Further, the fuel cell is assembled by sandwiching the MEA with a separator having a gas supply function, a current collecting function, particularly an important drainage function in the cathode, and the like made of a metal material, graphite, carbon composite and the like. The electric load is electrically connected to the anode and the cathode.

[Raw materials for hydrogen production]
As a raw material for hydrogen production, any substance that can obtain a reformed gas containing hydrogen by a reforming method such as a steam reforming method, an autothermal reforming method, or a partial oxidation method can be used. For example, compounds having carbon and hydrogen in the molecule such as hydrocarbons, alcohols and ethers can be used. Preferable examples that can be obtained inexpensively for industrial use or consumer use include methanol, ethanol, dimethyl ether, city gas, LPG (liquefied petroleum gas), gasoline, kerosene and the like. Of these, kerosene is preferable because it is easily available for industrial use and consumer use, and is easy to handle.

[Desulfurization]
Since sulfur in the raw material for hydrogen production has an effect of inactivating the reforming catalyst, it is desirably as low as possible, preferably 0.1 mass ppm or less, more preferably 50 mass ppb or less. For this reason, if necessary, the raw material for hydrogen production can be desulfurized in advance. There is no restriction | limiting in particular in the sulfur concentration in the raw material used for a desulfurization process, If it can convert into the said sulfur concentration in a desulfurization process, it can use preferably.

  There is no particular limitation on the desulfurization method, but an example is a method in which hydrogen sulfide produced by hydrodesulfurization in the presence of a suitable catalyst and hydrogen is absorbed by zinc oxide or the like. Examples of the catalyst that can be used in this case include catalysts containing nickel-molybdenum, cobalt-molybdenum, and the like as components. On the other hand, if necessary in the presence of an appropriate sorbent, a method of sorbing a sulfur component in the presence of hydrogen can also be employed. Examples of sorbents that can be used in this case include sorbents mainly composed of copper-zinc as shown in Japanese Patent No. 2654515, Japanese Patent No. 2688749, and so on. Examples thereof include an adhesive.

[Composition of hydrogen-containing gas]
When the steam reforming reaction is used in the reformer, the composition of the gas that has passed through the reformer (mol% in dry base) is typically, for example, 63 to 73% hydrogen, 0.1 to 5% methane, 5 to 5 carbon dioxide. 20%, carbon monoxide 5-20%. On the other hand, the composition when using the autothermal reforming reaction (mol% in dry base) is usually 23 to 37% hydrogen, 0.1 to 5% methane, 5 to 25% carbon dioxide, 5 carbon monoxide, for example. -25%, nitrogen 30-60%. The composition in the case of using a partial oxidation reaction (mol% on a dry basis) is usually 15 to 35% hydrogen, 0.1 to 5% methane, 10 to 30% carbon monoxide, 10 to 40% carbon dioxide, Nitrogen is 30-60%.

  In addition, the composition of the gas that has passed through the reformer and shift reactor (mol% or mol ppm of dry base) is usually, for example, 65 to 75% of hydrogen, 0. 1 to 5%, carbon dioxide 20 to 30%, carbon monoxide 1000 ppm to 10000 ppm. On the other hand, the composition when using the autothermal reforming reaction (mol% or mol ppm of dry base) is usually 25 to 40% hydrogen, 0.1 to 5% methane, 20 to 40% carbon dioxide, one Carbon oxide is 1000 ppm to 10000 ppm and nitrogen is 30 to 54%. The composition when using the partial oxidation reforming reaction (mol% in dry base) is usually 20 to 40% hydrogen, 0.1 to 5% methane, 1000 ppm to 10000 ppm carbon monoxide, 20 to 45% carbon dioxide, for example. Nitrogen 30-55%.

  The composition of the gas that has passed through the reformer, shift reactor, and selective oxidation reactor (mol% of the dry base) is usually, for example, 65 to 75% hydrogen, 0. 1 to 5%, carbon dioxide 20 to 30%, nitrogen 1 to 10%. On the other hand, the composition (dry base mol%) when using the autothermal reforming reaction is usually, for example, 25 to 40% hydrogen, 0.1 to 5% methane, 20 to 40% carbon dioxide, and 30 to 54 nitrogen. %. The composition when the partial oxidation reforming reaction is used (mol% in dry base) is usually 20 to 40% hydrogen, 0.1 to 5% methane, 20 to 45% carbon dioxide, and 30 to 55% nitrogen. is there.

[Other equipment]
Known components of the fuel cell system can be appropriately provided as necessary. Specific examples include a means for supplying an oxygen-containing gas such as air to the cathode of the fuel cell, a steam generator for generating steam for humidifying the gas supplied to the fuel cell, and various devices such as the fuel cell. Cooling system, pressurizing means such as pumps, compressors and blowers for pressurizing various fluids, flow regulating means such as valves for regulating the flow rate of fluids, or shutting off / switching the flow of fluids Channel shut-off / switching means, heat exchanger for heat exchange / recovery, vaporizer for vaporizing liquid, condenser for condensing gas, heating / heat-retaining means for externally heating various devices with steam, etc. Storage means, instrumentation air and electrical systems, control signal systems, control devices, output and power electrical systems, and the like.

FIG. 4 shows the result of measuring the pressure loss by flowing a gas of 50 L / min per one reforming tube with the original pressure of the cylinder being 0.17 MPa and assuming the actual reformed gas flow rate. The reformer used has the form shown in FIG. 1 in which circular reformer tubes are arranged at equal intervals on one circumference. The cross-sectional area of one tube is 283 mm ² , and its length is The diameter of the catalyst particles filled therein was 3 mm, and the layer height was 600 mm. In addition, a total of 12 reforming tubes (reforming tubes A to L) were used. The cross-sectional area ratio between the orifice and the reforming pipe (orifice cross-sectional area / reforming pipe cross-sectional area) was set to 1/40. The pressure loss of the catalyst layer shown in FIG. 4 means the pressure loss measured without attaching the orifice plate to the reaction tube filled with the catalyst, and the pressure loss of the orifice is provided with the orifice plate without filling the catalyst. The pressure loss measured in the state is meant, and the sum means the pressure loss measured in a state where the catalyst is filled and the orifice plate is provided. From these results, the standard deviation, average value and variation (= standard deviation / average value) of pressure loss were calculated and summarized in the table below.

  If an orifice with a pressure loss variation of 1.6% is installed compared to a catalyst layer pressure loss variation of 8.2%, the pressure loss variation of the entire reforming pipe is 2.8%, which is compared with the catalyst layer alone. And became smaller. Thereby, the drift of each reforming tube was suppressed, and the temperature distribution could be made uniform.

It is typical sectional drawing which shows the part of the reaction tube about one form of the reformer of this invention. It is a schematic diagram which shows one form of the reformer of this invention. It is typical sectional drawing which shows the part of the reaction tube about another form of the reformer of this invention. It is a graph which shows the pressure loss measurement result in an Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Gas supply port 2 Manifold 3 Reaction tube 4 Catalyst layer 5 Orifice plate 6 Orifice 7 Manifold 8 Gas discharge port 11 Gas supply port 12 Manifold area 13 Reaction tube 14 Catalyst layer 15 Dispersion plate 16 Through-hole 17 Void 18 Gas discharge port 19 Void 30 circumference (virtual line)
31 Container 32 Burner 33 Fuel supply pipe for combustion 34 Air supply pipe for combustion 35 Combustion gas discharge port

Claims (7)

In a reformer having a reforming reaction tube having a catalyst layer for reforming a raw material for hydrogen production to produce a hydrogen-containing gas containing hydrogen,
A reformer comprising pressure loss generating means for generating a pressure loss in the reforming reaction tube. The reformer according to claim 1, which is used for a fuel cell system. The reformer according to claim 1 or 2, wherein a plurality of the reforming reaction tubes are provided, and each reforming reaction tube is provided with an orifice as the pressure loss generating means. The pressure loss under the rated operating condition of the orifice provided in each reforming reaction tube is 2 to 10 times the average value of the pressure loss under the rated operating condition of the catalyst layer provided in each reforming reaction tube. The reformer described. The reformer according to claim 3, wherein a cross-sectional area of an orifice provided in each reforming reaction tube is 1 / 10,000 or more and 1/4 or less of a cross-sectional area in the flow path direction of the reforming reaction tube. The reformer according to claim 1 or 2, wherein a cross section of the reforming reaction tube in a flow path direction is an annular shape, and the reforming reaction tube includes an annular dispersion plate as the pressure loss generating means. A reformer having a reforming reaction tube having a catalyst layer for producing a hydrogen-containing gas containing hydrogen by reforming a raw material for hydrogen production, and a fuel cell using the hydrogen-containing gas as a fuel. In the fuel cell system,
The fuel cell system, wherein the reformer comprises pressure loss generating means for generating a pressure loss in the reforming reaction tube.

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