JP2004288434A - Hydrogen production device and fuel cell system - Google Patents

Abstract

An object of the present invention is to provide a hydrogen production apparatus and a fuel cell system that are highly efficient, compact, have a long life, and can expand the range of operating conditions.
A reforming tube for obtaining a reformed gas containing hydrogen by steam reforming a hydrocarbon oil, a burner for heating the reforming tube, a steam generator for generating steam required for steam reforming, and reforming In a hydrogen production apparatus having a CO converter for reducing the CO concentration in a gas by a shift reaction and a selective oxidizer for further reducing the CO concentration in a reformed gas by a selective oxidation reaction, the first column, which is a vertical columnar region, A region, an annular second region on an outer peripheral side thereof, an annular third region on an outer peripheral side thereof, an annular fourth region on an outer peripheral side thereof, and the second to fourth regions are concentric with the first region. One area has a burner, the second area has a reforming tube, the third area has a steam generator, and the fourth area has a CO converter and a selective oxidizer. A fuel cell system having this device.
[Selection] Fig. 2

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a hydrogen production apparatus for producing hydrogen from a hydrocarbon oil such as kerosene. Further, the present invention relates to a fuel cell system including the hydrogen production device.
[0002]
[Prior art]
2. Description of the Related Art In recent years, fuel cells have attracted attention as environmentally friendly energy conversion technologies. In many types of fuel cells, such as polymer electrolytes, it is hydrogen that actually undergoes an electrode reaction at the fuel electrode of the fuel cell. However, hydrocarbon oils such as kerosene are superior to hydrogen in terms of the supply system and handling.Hydrogen oils such as kerosene are reformed to produce a hydrogen-containing reformed gas, which is then converted to fuel cells. A fuel cell system for supplying a fuel electrode has been developed.
[0003]
For example, in a polymer electrolyte fuel cell, since carbon monoxide adversely affects the cell performance, it is necessary to reduce the CO concentration in the fuel supplied to the fuel electrode. An oxidizer is provided. Also, when steam is used for reforming, a steam generator is provided, and since sulfur becomes a poisoning substance such as a reforming catalyst, a desulfurizer for removing sulfur in hydrocarbon oil is provided. There are many.
[0004]
As described above, several devices are required to produce a hydrogen-containing gas suitable for supply to the fuel electrode from hydrocarbon oil.
[0005]
Patent Document 1 discloses that a reforming reaction tube includes a concentric inner tube, an outer tube, and an intermediate tube, and a first annular portion into which a raw material gas is introduced and a catalyst layer are formed between the inner tube and the intermediate tube. The second annular portion, which is formed between the intermediate pipe and the outer pipe, and through which the reformed gas flows, communicates with the first annular portion and the second annular portion, and the reformed gas flowing out of the catalyst layer is discharged to the second annular portion. 2 shows a reforming reaction tube comprising an end cap for flowing into an annular portion 2.
[0006]
Patent Document 2 discloses a multi-tube reactor in which a plurality of double-tube reactors are concentrically arranged in a cylindrical reactor. In this device, a plurality of reaction tubes of a double tube type are arranged concentrically in a cylindrical container, a reforming catalyst is filled between an outer tube and an inner tube, and reformed gas flows through the inner tube. Outflow. The source gases are respectively introduced from the source gas collecting pipes into the respective reaction tubes by the raw material connecting pipes connected thereto, and the reformed gas is collected from the respective reaction tubes into the reformed gas collecting pipes connected to the reformed gas connecting pipes.
[0007]
However, the fuel cell system is often required to be compact and lightweight, but in the above-described conventional technology, the apparatus for producing hydrogen is not excellent in compactness, and further miniaturization is desired. I was Also, the fuel cell system is required to have high efficiency, and accordingly, the hydrogen production apparatus is also required to have high efficiency. In this regard, further improvement has been desired.
[0008]
[Patent Document 1]
JP-A-11-292502
[Patent Document 2]
JP-A-2002-274807
[0009]
[Problems to be solved by the invention]
An object of the present invention is to provide a hydrogen production apparatus for producing a hydrogen-containing gas from hydrocarbon oil, which can improve thermal efficiency, reduce the occupied volume, extend the life and extend the range of operating conditions. It is.
[0010]
Another object of the present invention is to provide a highly efficient and compact fuel cell system.
[0011]
[Means for Solving the Problems]
According to the present invention, a reforming tube for obtaining a reformed gas containing hydrogen by steam reforming a hydrocarbon oil, a burner for heating the reforming tube, a steam generator for generating steam required for the steam reforming, A CO converter for reducing the CO concentration in the reformed gas by a shift reaction, and a selective oxidizer for further reducing the CO concentration in the reformed gas in which the CO concentration is reduced by the CO converter by a selective oxidation reaction. In hydrogen production equipment,
A first region which is a vertical columnar region, a second region which is located on the outer peripheral side of the first region and is concentric with the first region, and a second region which is located on the outer peripheral side of the second region. A third region which is an annular region concentric with the first region, and a fourth region which is located on the outer peripheral side of the third region and is concentric with the first region,
Having the burner in the first region;
Having the reforming tube in the second region,
Having the steam generator in the third region;
Having the CO transformer and the selective oxidizer in the fourth region
A hydrogen production apparatus is provided.
[0012]
In this hydrogen production apparatus, the first region, the second region, and the third region are formed in one sealable container, and the fourth region is formed in another sealable container different from the container. There is a form.
[0013]
Further, there is a form in which the first region, the second region, the third region, and the fourth region are formed in one sealable container.
[0014]
It is preferable that the hydrogen production device has a combustion gas flow path for heating the reforming tube, the steam generator, the CO shift converter, and the selective oxidizer in this order by the combustion gas of the burner.
[0015]
Further, a desulfurizer for desulfurizing the hydrocarbon oil may be provided in the third region and in the combustion gas passage.
[0016]
Alternatively, further comprising a desulfurizer filled with a desulfurizing agent in a sealable container in which none of the first region, the second region, the third region and the fourth region are formed,
A flow path for heating the desulfurizer with the combustion gas that has heated the reforming tube, the steam generator, the CO shift converter, and the selective oxidizer may be provided. .
[0017]
It is preferable that the burner is arranged vertically downward and has a combustion tube.
[0018]
In the fourth region, there is a form in which the CO converter and the selective oxidizer are vertically arranged.
[0019]
Alternatively, in the fourth region, there is a form in which a CO converter and a selective oxidizer are arranged in the circumferential direction.
[0020]
It is preferable to have a cooling line for cooling the CO shift converter and the selective oxidizer by the steam generated by the steam generator.
[0021]
It is preferable that water having a pressure of 500 kPa to 1000 kPa is supplied to the steam generator.
[0022]
According to the present invention, a reforming tube for obtaining a reformed gas containing hydrogen by steam reforming a hydrocarbon oil, a burner for heating the reforming tube, a steam generator for generating steam required for the steam reforming, A CO converter for reducing the CO concentration in the reformed gas by a shift reaction, and a selective oxidizer for further reducing the CO concentration in the reformed gas in which the CO concentration is reduced by the CO converter by a selective oxidation reaction. In a fuel cell system having a hydrogen production device and a fuel cell using the reformed gas produced by the hydrogen production device as fuel,
A first region which is a vertical columnar region, a second region which is located on an outer peripheral side of the first region and is concentric with the first region, and an outer periphery of the second region; A third region, which is a concentric annular region with the first region, and a fourth region which is concentric with the first region and located on the outer peripheral side of the third region. The first region has the burner, the second region has the reformer tube, the third region has the steam generator, and the fourth region has the CO converter and the selective oxidizer. Having
A fuel cell system is provided.
[0023]
In this fuel cell system, a combustion catalyst is disposed in the second region, and
There is a form having a line for leading anode offgas of a fuel cell to the combustion catalyst.
The fuel cell system according to claim 12.
[0024]
Alternatively, there is a form in which the burner is a co-firing burner capable of burning the anode offgas of the fuel cell and the hydrocarbon oil, and has a line for leading the anode offgas of the fuel cell to the burner.
[0025]
BEST MODE FOR CARRYING OUT THE INVENTION
(Hydrocarbon oil)
As a raw material for producing hydrogen, an organic compound that is liquid at 25 ° C. and 0.101 MPa, contains a compound having carbon and hydrogen in its molecule, and can generate hydrogen by a steam reforming reaction can be used. For example, petroleum hydrocarbon oils such as gasoline, naphtha, kerosene, and light oil obtained from petroleum can be used. Also, liquefied petroleum gas can be used.
[0026]
(Desulfurization)
Since sulfur has an effect of inactivating the steam reforming catalyst, it is preferable that the sulfur concentration in the hydrocarbon oil supplied to the steam reforming reactor be as low as possible. It is preferably at most 50 mass ppm, more preferably at most 20 mass ppm. Thus, if necessary, the hydrocarbon oil can be desulfurized before steam reforming. Hydrocarbon oil which has been desulfurized before supply to the hydrogen production apparatus of the present invention may be used, or a desulfurizer may be provided in the hydrogen production apparatus. When a desulfurizer is provided, the hydrocarbon oil supplied to the desulfurizer can be used as long as the hydrocarbon oil can be desulfurized to the above-mentioned sulfur concentration in the desulfurizer.
[0027]
As the desulfurization method, a method of sorbing sulfur in the presence of a suitable sorption type desulfurization catalyst is preferable from the viewpoint of simplification of the system, simplicity of the control method, and ease of catalyst pretreatment. The sorption type desulfurization catalyst removes sulfur by adsorption and / or absorption. For example, a catalyst containing Zn / ZnO, Cu / CuO, Ni / NiO or the like is preferable from the viewpoint of sulfur adsorption capacity.
[0028]
When using a sorption type desulfurization catalyst, the desulfurization temperature is preferably from 100 to 350 ° C from the viewpoint of making the desulfurization catalyst function well.
[0029]
Further, the desulfurization catalyst may be one that promotes the decomposition reaction of hydrocarbon oil as well as the sulfur removal and absorption. In this case, the desulfurizer also functions as a pre-reformer that partially decomposes the hydrocarbon oil.
[0030]
(Reforming tube)
In a reforming tube that performs a steam reforming reaction, hydrocarbon oil and water react to produce carbon monoxide and hydrogen. Since this reaction involves a large endotherm, external heating is required. For this reason, a burner is provided in the hydrogen production apparatus of the present invention, and the reforming tube is externally heated by combustion heat.
[0031]
For example, hydrocarbon oil and steam can be supplied to a reforming catalyst layer formed by filling a reforming catalyst in a reforming tube, and the reforming catalyst layer can be heated from outside the reforming tube.
[0032]
The steam reforming reaction can be performed in the presence of a metal catalyst represented by a Group VIII metal such as nickel, cobalt, iron, ruthenium, rhodium, iridium, and platinum.
[0033]
The reaction can be carried out at a temperature of 450 ° C to 900 ° C, preferably 500 ° C to 850 ° C, more preferably 550 ° C to 800 ° C.
[0034]
The pressure of the reforming reaction can be appropriately set, but is preferably in the range of atmospheric pressure to 20 MPa, more preferably in the range of atmospheric pressure to 5 MPa, and still more preferably in the range of atmospheric pressure to 1 MPa.
[0035]
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 hydrocarbon oil (steam / carbon ratio), and this value is preferably 0.5 to 10, and more preferably 0.5 to 10. Is 1 to 7, more preferably 2 to 5. The liquid hourly space velocity (LHSV) at this time can be represented by A / B when the flow velocity of the hydrocarbon fuel in the liquid state is A (L / h) and the volume of the catalyst layer is B (L). Preferably 0.05 to 20 h ^-1 , More preferably 0.1 to 10 h ^-1 , More preferably 0.2 to 5 hours ^-1 Is set in the range.
[0036]
The form of the reforming tube is preferably a double tube reactor from the viewpoint of heat balance. In the double tube reactor, the outer ring of the double tube is filled with the reforming catalyst, and the inner tube is not filled with the catalyst. The raw material for reforming is introduced into the outer ring part, and causes a steam reforming reaction when passing through the catalyst layer, and is turned back at the end opposite to the side where the raw material is introduced, and the raw material is introduced through the inner tube. From the side end.
[0037]
〔burner〕
As the fuel supplied for burning the burner, combustible materials can be used as appropriate. For example, it is preferable to use a hydrocarbon oil used as a raw material for hydrogen production for combustion, from the viewpoint of simplification of a hydrogen production apparatus or ancillary equipment thereof. When the hydrogen production apparatus is used in a fuel cell system, it is preferable to use anode off-gas discharged from the anode (fuel electrode) of the fuel cell from the viewpoint of energy efficiency.
[0038]
The maximum combustion temperature of the burner is preferably set to 800 to 1000C from the viewpoint of the heat resistant temperature of the reforming tube material.
[0039]
[CO transformer]
The reformed gas generated in the reforming tube contains carbon monoxide, carbon dioxide, methane, and steam in addition to hydrogen. In order to increase the concentration of hydrogen and to reduce the concentration of carbon monoxide because carbon monoxide can be a catalyst poison, the CO converter converts carbon monoxide with water and converts it to hydrogen and carbon dioxide. . Using a mixed oxide of Fe-Cr, a mixed oxide of Zn-Cu, a catalyst containing a noble metal such as platinum, ruthenium, and iridium, the carbon monoxide content (mol% on a dry basis) is preferably 2% or less, more preferably It can be reduced to preferably 1% or less, more preferably 0.5% or less.
[0040]
The shift reaction can also be carried out in two stages, in which case the CO converter is divided into two. One is a high temperature CO transformer with a relatively high rated operating temperature, and the other is a low temperature CO transformer with a relatively low rated operating temperature. High-temperature CO conversion can be performed using a high-temperature CO conversion catalyst having a suitable use temperature of 300 to 500 ° C, and low-temperature CO conversion is performed using a low-temperature CO conversion catalyst having a suitable use temperature of 100 to 300 ° C. be able to. A high-temperature CO converter and a low-temperature CO converter are installed in order from the upstream with respect to the flow of the reformed gas.
[0041]
CO conversion is gas space velocity GHSV (15 ° C, 0.101MPa conversion) 800-3000h ^-1 It is preferable to carry out.
[0042]
[High-temperature CO transformer]
For the high-temperature CO shift converter, a high-temperature CO shift catalyst that is a catalyst having a shift reaction activity at 300 to 500 ° C. can be used.
[0043]
The high-temperature CO conversion catalyst preferably contains at least one metal selected from iron, chromium, and copper, in addition to sulfur, from the viewpoint of shift reaction activity at 300 to 500 ° C. For example, the mass composition of the high-temperature shift catalyst on an oxide basis is preferably one containing sulfur and containing 60 to 95% of iron, 1 to 30% of chromium, and 0.1 to 10% of copper. The shape is preferably spherical, cylindrical, massive, or ring-like, and any molding method may be used, but tablet molding and extrusion molding are preferred.
[0044]
In the high-temperature CO conversion process, GHSV is 200 to 10000 hours ^-1 (GHSV represents a gas hourly space velocity in terms of 0.101 MPa at 15 ° C .; the same applies hereinafter). 200hr ^-1 By doing so, the gas processing capacity and economic efficiency can be improved, and 10,000 hours ^-1 If it is below, it is excellent in the CO concentration reducing ability.
[0045]
[Low-temperature CO transformer]
For the low-temperature CO shift converter, a low-temperature CO shift catalyst that is a catalyst having a shift reaction activity at 100 to 300 ° C. can be used.
[0046]
As the low-temperature shift catalyst, those containing at least one metal selected from copper, zinc, nickel, iron, manganese, platinum, gold, ruthenium, rhodium and rhenium are preferable from the viewpoint of shift reaction activity. The total amount of metal contained is preferably 5 to 90% by mass based on the oxide, and the shape is preferably spherical, columnar, massive, or ring-like. The molding method may be any method, but tablet molding and extrusion may be performed. Molding is preferred. The method for preparing the catalyst is not particularly limited, but a coprecipitation method, a gel kneading method and an impregnation method are preferred.
[0047]
The gas supplied to the low-temperature CO shift converter preferably has a CO concentration (dry base mol%) of 2% or more from the viewpoint of preventing the load on the high-temperature CO shift catalyst from increasing and preventing deterioration. The CO concentration (mole% on a dry basis) is preferably 20% or less from the viewpoint of preventing the load on the low-temperature CO shift catalyst from increasing and preventing catalyst deterioration. Therefore, in a high-temperature CO converter, it is preferable to reduce the CO concentration to this range.
[0048]
As for the gas supplied to the low-temperature conversion CO converter, GHSV is 200 to 50,000 hr. ^-1 It is preferable that 200hr ^-1 By doing so, the gas processing capacity and economic efficiency can be improved, and 50,000 hours ^-1 If it is below, it is excellent in the CO concentration reducing ability.
[0049]
(Selective oxidizer)
For example, in a polymer electrolyte fuel cell system, it is preferable to further reduce the concentration of carbon monoxide. For this purpose, the outlet gas of the CO converter can be treated by a selective oxidizer. In the selective oxidizer, CO is selectively oxidized to carbon dioxide.
[0050]
For this reaction, using a catalyst containing iron, cobalt, nickel, ruthenium, rhodium, palladium, osmium, iridium, platinum, copper, silver, gold, etc., preferably 0.5 to the remaining carbon monoxide moles. The concentration of carbon monoxide is increased by selectively converting carbon monoxide to carbon dioxide by adding 10 to 10 times, more preferably 0.7 to 5 times, and still more preferably 1 to 3 times of oxygen. Preferably, it is reduced to 10 ppm or less. In this case, the concentration of carbon monoxide can be reduced by reacting the coexisting hydrogen with the coexisting hydrogen to generate methane. For example, air can be used as the oxygen source.
[0051]
The selective oxidation can be performed using a selective oxidation catalyst having a suitable use temperature of 100 to 200 ° C. The molar ratio of supplied oxygen and CO (O ₂ / CO ratio) is preferably 1.0 to 2.0, and 7000 to 10000 h in GHSV (15 ° C., 0.101 MPa conversion). ^-1 Is preferred.
[0052]
[Water / steam system]
In order to supply steam required for steam reforming, the hydrogen production device includes a water evaporator. Further, from the viewpoint of stable operation, it is preferable that the water evaporator has a superheat section for heating the generated steam.
[0053]
Regarding the temperature of the water supplied to the hydrogen production apparatus, water at normal temperature can be used without particular heating, or can be, for example, 35 to 60 ° C. The pressure can be appropriately set, but is preferably 500 kPa to 1000 kPa from the viewpoint of improving thermal efficiency by promoting heat recovery.
[0054]
The steam to be generated may be, for example, a saturated vapor pressure according to the pressure, but it may be superheated to, for example, 250 to 450 ° C.
[0055]
[Arrangement]
Hereinafter, an embodiment of the hydrogen production apparatus of the present invention will be described in detail with reference to the drawings.
[0056]
FIG. 1 schematically shows the outline of a hydrogen production apparatus. The hydrogen production device has four regions. The first area 1 is a cylindrical area arranged vertically, the second area 2 is an annular area arranged on the outer periphery, and the third area 3 is an annular area arranged on the outer periphery. The fourth region 4 is an annular region further disposed on the outer periphery.
[0057]
A burner is provided in the first region, a reforming tube is provided in the second region, a steam generator is provided in the third region, and a CO converter and a selective oxidizer are provided in the fourth region.
[0058]
All of the first to fourth regions may be formed in one sealable container. In this case, a cylindrical container can be used as the container. In this mode, the whole area can be kept in one container, the outside of which is covered with a heat insulating material, and / or the outer wall of the container is made to have a vacuum insulation structure, so that the entire container can be kept warm. It is preferable from the viewpoint of reducing the heat insulating material space. The vacuum insulation structure has a container wall having a double structure of an inner wall and an outer wall, and has a vacuum between the inner wall and the outer wall.
[0059]
Also, not all regions need to be in one container, for example, the first to third regions are formed in one sealable container, and the fourth region is sealed independently of this container. It can also be formed in a possible container. In this case, the former container may be cylindrical, and the latter container may be annular, the two containers may be installed at an interval, and a flow path connecting the two containers may be provided. It is preferable that the outer walls of both containers have a vacuum insulation structure. This mode is suitably adopted when it is better not to conduct heat directly between the third region and the fourth region, for example, in order to avoid overheating of the CO converter and the selective oxidizer in the fourth region. At this time, it is preferable to keep the temperature of the two containers together integrally from the viewpoint of thermal efficiency and the viewpoint of reducing the space for the heat insulating material.
[0060]
[First embodiment]
FIG. 2 schematically shows a vertical cross section and FIG. 3 shows a schematic horizontal cross section of one embodiment of the hydrogen production apparatus. Note that the following drawings are for explanation, and do not necessarily represent the device exactly. In this embodiment, the first to third regions are formed adjacent to each other in one cylindrical container 101, and the fourth region is formed in an independent annular container 102, and connects the third region and the fourth region. And a connecting portion 103 to be connected. The central axes of all regions coincide.
[0061]
In the first region 1, a burner 11 is provided downward through the upper surface of the container 101, and a flame 12 is formed during combustion. It is preferable that the burner is directed downward because dripping can be effectively prevented. It also has a combustion cylinder 13, and the combustion cylinder divides a first region and a second region. The combustion cylinder reaches the bottom of the vessel, but has an opening 14 near the lower end, and the combustion gas of the burner flows to the adjacent second region 2 through the opening. The burners are provided at positions along the central axis of all the regions.
[0062]
For example, a ceramic cylinder can be used as the combustion cylinder, and has an opening at the bottom. By using the combustion tube, the reforming tube in the second region can be uniformly heated by the combustion gas. The openings can be appropriately provided so that the combustion gas uniformly heats the reforming tube. For this purpose, for example, a plurality of openings can be provided between about 30% of the lower part of the combustion cylinder length and the lower end. Further, a heat insulating material 15 can be provided on the bottom surface of the first region.
[0063]
In a fuel cell system, this burner can be a co-firing burner capable of burning both hydrocarbon oil and anode off-gas of the fuel cell. By doing so, the anode off-gas can be effectively used, the consumption of hydrocarbon oil can be reduced, and this is preferable from the viewpoint of thermal efficiency.
[0064]
A double-tube reforming tube 21 having a closed lower end is provided in the second region, and the reforming tube is heated by the combustion gas. On the other hand, a raw material gas in which hydrocarbon oil and steam are mixed is supplied from a raw material gas manifold 22 to an outer ring portion of the reforming tube, and a reforming reaction occurs in a reforming catalyst layer 21a provided in the outer ring portion. The reformed gas is converted into the reformed gas, and the reformed gas rises in the inner pipe portion of the reforming pipe and reaches the reformed gas manifold 36 via the communication section 24. The partition 23 partitions between the second region and the third region. The partition can be formed of a heat insulating material.
[0065]
Note that it is preferable to provide a heat insulating material 110 on the bottom surfaces of the first region and the second region of the container 101 from the viewpoint of thermal efficiency.
[0066]
In addition, an orifice may be attached to the reforming tube outlet reformed gas flow path to make the pressure loss of a plurality of reforming tubes uniform, thereby achieving stability. For example, an orifice can be provided at the outlet of each reforming tube (the outlet of the inner tube). The orifice diameter is such that the differential pressure at the orifice portion is preferably about 50% to 300%, more preferably about 100% to 150% of the differential pressure of the reforming tube filled with the catalyst. By attaching the orifice, the distribution of the source gas to the plurality of reforming tubes becomes uniform, and the variation in the temperature of the reforming tube is reduced, so that it is easy to control the temperature of the reforming tube and to obtain a uniform reformed gas. it can.
[0067]
A plurality of reforming tubes are provided along the circumference around the central axis of the entire region so as to surround the burner. The number is preferably 6 to 12 in consideration of the size of the second region and the flow dispersibility of the source gas. Here, nine reforming tubes are provided. Further, fins can be provided on the outer surface of the reforming tube. Thereby, the heat of the combustion gas is more easily transmitted to the catalyst inside the reforming tube, which is preferable.
[0068]
In the third area, a water evaporator 31 and a raw material gas preheater 32 are provided. The combustion gas supplied from the second region contacts the raw material gas preheater and the steam generator in this order, heats them, and is discharged from the combustion gas discharge port 33 to the outside of the container 101. On the other hand, the water supplied from the water supply pipe 34 is turned into steam by the water evaporator, and this steam passes through the steam supply pipe 35 to cool the selective oxidizer and the CO converter in the fourth region as described later, and to cool itself. Is heated, mixed with the raw material in the mixer 51, and supplied to the raw material gas preheater 32. The source gas heated by the source gas preheater is supplied to the source gas manifold 22 for reforming. In FIG. 3, for the sake of explanation, the third region is divided into two parts, and the reformed gas manifold 36 and the water evaporator 31 are shown as if they are arranged in the horizontal direction. However, as shown in FIG. These are arranged above and below.
[0069]
The water evaporator and the raw material gas preheater have a form in which a single tube is wound in a coil shape in the circumferential direction of the third region.
[0070]
Furthermore, an air preheater for preheating burner combustion air may be provided in the third region for improving thermal efficiency. For example, a single tube wound in a coil shape in the circumferential direction of the third region is provided at the most downstream with respect to the flow of the reformed gas in the third region. Can be supplied to
[0071]
The inside of the fourth region is partitioned in the circumferential direction by vertical partition walls, and a high-temperature CO converter 41, a reformed gas cooler 42, a low-temperature CO converter 43, which is filled with a catalyst as needed in each partition, has a first section. The reformed gas air mixer 44, the first selective oxidizer 45, the second reformed gas air mixer 46, and the second selective oxidizer 47 are arranged in the circumferential direction. First, the reformed gas supplied from the reformed gas manifold 36 through the connection portion 103 has its CO concentration reduced by the shift reaction in the high-temperature CO shift catalyst layer 41a in the high-temperature CO shift converter 41 filled with the high-temperature CO shift catalyst. Is done. At this time, the high-temperature CO transformer is cooled by steam flowing through the cooling pipe 48 passing through the high-temperature CO transformer. The reformed gas that has passed through the high-temperature CO shift converter is cooled to a temperature suitable for low-temperature CO shift by the steam flowing through the cooling pipe in the reformed gas cooler 42 (the catalyst is not charged), and the low-temperature CO shift catalyst is charged. Is supplied to the low-temperature CO converter 43. Here, the CO concentration of the reformed gas is further reduced by the shift reaction. At this time, the low-temperature CO transformer is cooled by steam flowing through the cooling pipe passing through the low-temperature CO transformer. The reformed gas exiting the low-temperature CO converter is mixed with air for selective CO oxidation in a first reformed gas air mixer 44 (not filled with a catalyst). The reformed gas mixed with the air is further oxidized in the first selective oxidizer 45 filled with the selective oxidation catalyst, so that the CO concentration is further reduced. The reformed gas exiting the first selective oxidizer is further mixed with air in a second reformed gas air mixer 46 (not filled with a catalyst), and the second selective gas filled with a selective oxidation catalyst is mixed. The CO concentration in the oxidizer is reduced by the oxidation of CO, and the CO is taken out from the reformed gas outlet 50 as a reformed gas having a low CO concentration. It should be noted that a reformed gas flow path connecting between the devices 41 to 47, such as a reformed gas flow path connecting between the high-temperature CO converter 41 and the reformed gas cooler 42, is not shown.
[0072]
From the viewpoint of better mixing the reformed gas and the air, it is preferable that a baffle is arranged in each of the first and second reformed gas / air mixers, and a so-called static mixer is formed. Each of the first and second selective oxidizers is cooled by steam flowing through a cooling pipe passing therethrough. In addition, the cooling pipe does not need to be provided in the reformed gas air mixer.
[0073]
Although it is possible to perform the CO selective oxidation in one step, when the CO selective oxidation is performed in two steps as described above, for example, the CO concentration (on a molar basis on a dry basis) can be easily reduced from 1% to 10 ppm. Therefore, it is preferable. For example, the CO concentration (dry basis on a molar basis) can be reduced from 1% to 5000 ppm by the first CO selective oxidation, and can be reduced to 10 ppm by the second CO selective oxidation.
[0074]
On the other hand, the steam generated in the water evaporator 31 is supplied to the steam manifold 49a from the steam supply pipe 35, and the high-temperature CO converter 41, the reformed gas cooler 42, the low-temperature CO converter 43, the first selective oxidizer 45, And while cooling the reformed gas when passing through a cooling pipe disposed in the second selective oxidizer 47, the reformed gas itself is heated, collected in the steam manifold 49b, and combined with the hydrocarbon oil desulfurized in the mixer 51. Mixed. The cooling pipe is a plurality of pipes provided in a vertical direction like a so-called shell-and-tube heat exchanger, and only a part is shown in FIG.
[0075]
The desulfurization of the hydrocarbon oil is performed in a desulfurizer (not shown) independent of the containers 101 and 102. The desulfurizer is heated by the combustion gas discharged from the combustion gas outlet 33. The structure of this desulfurizer is, for example, a double tube type structure, in which the outside is a desulfurization catalyst layer, and the raw material flows from the bottom to the top, and the combustion flows through the inner tube so that the desulfurization reaction temperature becomes 100 to 300 ° C. Temperature can be controlled by gas.
[0076]
[Second embodiment]
FIG. 4 shows another embodiment of the hydrogen production apparatus of the present invention. This embodiment has a combustion catalyst layer 25 in a second region, and an anode off-gas supply pipe 26 for supplying an anode off-gas of a fuel cell to the combustion catalyst. The burner only needs to burn hydrocarbon oil and need not be a co-fired burner. The combustion gas of the burner in which oxygen remains and the anode off-gas are burned by the combustion catalyst, and the combustion gas is supplied to the second region. The combustion catalyst layer can be provided so that all the combustion gas of the burner passes through the combustion catalyst layer. For example, it can be provided around the reformer pipe 21 over the entire cross section of the combustion gas flow path of the burner.
[0077]
This mode is preferable in terms of homogenizing the temperature distribution of the reforming tube and improving the properties of the exhaust gas.
[0078]
The combustion catalyst can be appropriately selected from known combustion catalysts. For example, an active carrier such as silica or alumina is supported on a honeycomb carrier such as ceramics or metal, and a noble metal such as Pt or Pd or a composite oxide is further supported thereon. Can be used.
[0079]
Except for the above, it is the same as the first embodiment.
[0080]
[Third embodiment]
FIG. 5 shows still another embodiment of the hydrogen production apparatus of the present invention. In this embodiment, all of the first to fourth regions are formed adjacent to each other in one cylindrical container 104. The desulfurizer 37 is provided in the container 104. Further, the inside of the fourth region is vertically partitioned by horizontal partition walls, and a high-temperature CO converter 41, a low-temperature CO converter 43, and a first reformed gas air in which each partition is filled with a catalyst as needed. The mixer 44, the first selective oxidizer 45, the second reformed gas / air mixer 46, and the second selective oxidizer 47 are arranged in a vertical direction. A heat insulating material 111 is provided on the bottom surface of the first to third regions of the container 104.
[0081]
The first region is the same as in the second embodiment. The hydrocarbon oil is burned by the burner 11, and the combustion gas is supplied to the second region to heat the reforming pipe 21. In the combustion catalyst layer 25, the anode off-gas supplied from the anode off-gas supply pipe 26 is burned by the burner combustion gas, and the combustion gas further heats the reforming pipe downstream thereof and is supplied to the third region.
[0082]
In the third area, a water evaporator 31 is provided inside and a desulfurizer 37 is provided outside, and each is heated by a combustion gas. A raw material preheater 38 is provided below the raw material preheater 38, and is heated by the combustion gas after heating the water evaporator and the desulfurizer. The combustion gas is discharged out of the container 104 from the fuel gas outlet 33 located on the bottom surface of the container in the third region.
[0083]
The water is supplied from a water supply pipe 34a, turned into steam in a water evaporator 31, and supplied to a raw material / steam mixing section 39. Further, the water supplied from the water supply pipe 34b cools the CO converter and the like provided in the fourth area and is heated by itself, and is supplied to the raw material / steam mixing section 39 as steam. On the other hand, the hydrocarbon oil as a raw material is supplied from a raw material supply pipe 52 to a raw material preheater 38, where it is preheated and desulfurized by a desulfurizer 37. The desulfurized raw material is supplied to a raw material / steam mixing section 39. The gas mixture (raw material gas) of the raw material and steam formed in the raw material / steam mixing section 39 is supplied from the raw material gas manifold 22 to the outer ring portion of the reforming pipe 21 to be converted into a reformed gas. It is supplied to the high-temperature CO converter 41 via the reformed gas manifold 36 by ascending the pipe portion. The reformed gas is supplied to the low-temperature CO converter 43 after the CO concentration is reduced by the shift reaction in the high-temperature CO converter, where the CO concentration is further reduced by the shift reaction. Thereafter, the reformed gas is mixed with air for selective oxidation of CO (supplied from outside) in a first reformed gas air mixer 44, and a selective oxidation reaction of CO is performed in a first selective oxidizer 45. As a result, the CO concentration is reduced. The reformed gas is further mixed with air for selective oxidation of CO (supplied from the outside) in a second reformed gas air mixer 46, and the CO concentration is reduced by a second selective oxidizer 47 to reduce the CO concentration. It is taken out from the reformed gas outlet 50 as a reformed gas having a concentration.
[0084]
Each of the steam generator and the raw material preheater is a coiled single tube wound in the circumferential direction of the third region. The desulfurizer 37 is formed by filling a desulfurizing agent 37a in an annular (doughnut-shaped) container.
[0085]
In the fourth region, the cooling pipe 48 penetrates the inside of the high-temperature CO transformer 41, the low-temperature CO transformer 43, the first and second selective oxidizers 45 and 47, and the water is heated inside the cooling pipe, Evaporates on the way and is superheated. The cooling pipe is a single pipe wound in a coil shape.
[0086]
In the fourth region, for example, a reformed gas flow path communicating between the high-temperature CO converter and the low-temperature CO converter is not shown.
[0087]
[Fuel cell system]
A fuel cell system of the present invention includes the above-described hydrogen production apparatus and a fuel cell using a hydrogen-containing gas obtained from the hydrogen production apparatus as a fuel electrode supply gas. In addition, other devices that are conventionally known as devices provided in a fuel cell system, such as a device for supplying an oxygen-containing gas such as air to a cathode, a device for extracting electricity from a fuel cell, an instrumentation control device, and the like. Can be appropriately provided.
[0088]
When the hydrogen production apparatus has a co-firing burner (for example, the first embodiment described above), the anode off-gas of the fuel cell can be burned by the burner. When the hydrogen production device has a combustion catalyst (for example, the second and third embodiments described above), combustion can be performed using the combustion catalyst. Therefore, the fuel cell system can have a line for leading the anode off-gas to the co-firing burner and a line for leading the anode off-gas to the combustion catalyst. This line can be appropriately formed by a pipe, a valve, or the like.
[0089]
With such a configuration, for example, the hydrocarbon oil is burned when the fuel cell system is started, but only the anode off-gas is burned during the rated operation, so that the consumption of the hydrocarbon oil for combustion can be suppressed.
[0090]
【The invention's effect】
According to the present invention, a reformer, a CO converter, a reactor such as a selective oxidizer, a water evaporator, and a heat exchanger such as a preheater required for hydrogen production can be integrally formed. By adopting an apparatus structure and an arrangement of the apparatus so that the reaction conditions such as the operating temperature and the space velocity of the catalyst are appropriate, it is possible to achieve a longer life and an expanded operating condition range defined by the catalyst life. Accordingly, a hydrogen production apparatus that is compact, has excellent thermal efficiency, has a long life, and has a wide range of operating conditions has been provided.
[0091]
Further, according to the present invention, a fuel cell system having high efficiency, compactness, long life, and a wide range of operating conditions is provided.
[Brief description of the drawings]
FIG. 1 is a conceptual diagram showing one embodiment of a hydrogen production apparatus of the present invention.
FIG. 2 is an explanatory view schematically showing a vertical cross section of the first embodiment of the hydrogen production apparatus of the present invention.
FIG. 3 is an explanatory view schematically showing a horizontal and vertical cross section of the first embodiment of the hydrogen production apparatus of the present invention.
FIG. 4 is an explanatory view schematically showing a vertical section of a second embodiment of the hydrogen production apparatus of the present invention.
FIG. 5 is an explanatory view schematically showing a vertical section of a third embodiment of the hydrogen production apparatus of the present invention.
[Explanation of symbols]
1 First area
2 Second area
3 Third area
4 fourth area
11 burners
12 Fire
13 Combustion cylinder
14 opening
15 Insulation
21 Reforming tube
21a Reforming catalyst layer
22 Source gas manifold
23 Partition
24 Communication section
25 Combustion catalyst layer
26 Anode off-gas supply pipe
31 Water evaporator
32 Source gas preheater
33 Combustion gas outlet
34 water supply pipe
35 Steam supply pipe
36 Reformed gas manifold
37 desulfurizer
37a Desulfurizer layer
38 Raw material preheater
39 Raw material / steam mixing section
41 High temperature CO transformer
41a High temperature CO shift catalyst layer
42 Reformed gas cooler
43 Low temperature CO transformer
44 First reformed gas-air mixer
45 First selective oxidizer
46 Second reformed gas air mixer
47 Second selective oxidizer
48 cooling pipe
49a, b Steam manifold
50 Reformed gas outlet
51 mixer
52 Raw material supply pipe
101 Cylindrical container for containing first to third areas
102 Annular container for independently storing fourth area
103 Connection
104 Cylindrical container for storing first to fourth areas
110 Insulation
111 Insulation

Claims (14)

Reforming pipe for obtaining a reformed gas containing hydrogen by steam reforming a hydrocarbon oil, a burner for heating the reforming pipe, a steam generator for generating steam required for the steam reforming, and the reformed gas CO converter in which the CO concentration in the CO is reduced by a shift reaction, and a hydrogen production apparatus having a selective oxidizer for further reducing the CO concentration in the reformed gas in which the CO concentration is reduced by the CO converter by a selective oxidation reaction ,
A first region which is a vertical columnar region, a second region which is located on the outer peripheral side of the first region and is concentric with the first region, and a second region which is located on the outer peripheral side of the second region. A third region which is an annular region concentric with the first region, and a fourth region which is located on the outer peripheral side of the third region and is concentric with the first region,
Having the burner in the first region;
Having the reforming tube in the second region,
Having the steam generator in the third region;
A hydrogen production apparatus comprising the CO converter and the selective oxidizer in the fourth region. The first region, the second region and the third region are formed in one sealable container, and the fourth region is formed in another sealable container different from the container. Hydrogen production equipment. The hydrogen production apparatus according to claim 1, wherein the first region, the second region, the third region, and the fourth region are formed in one sealable container. The hydrogen production apparatus according to claim 1, further comprising a combustion gas flow path for heating the reforming tube, the steam generator, the CO converter, and the selective oxidizer in this order by the combustion gas of the burner. The hydrogen production apparatus according to claim 4, further comprising a desulfurizer for desulfurizing hydrocarbon oil in the third region and in the combustion gas flow path. Further, a desulfurizer filled with a desulfurizing agent in a sealable container in which none of the first region, the second region, the third region and the fourth region are formed,
5. The hydrogen production apparatus according to claim 4, further comprising a flow path for heating the desulfurizer with a combustion gas that has heated the reforming tube, the steam generator, the CO shift converter, and the selective oxidizer. The hydrogen production apparatus according to claim 4, wherein the burner is disposed vertically downward and has a combustion cylinder. 2. The hydrogen production apparatus according to claim 1, wherein the CO converter and the selective oxidizer are arranged vertically in the fourth region. 3. The hydrogen production apparatus according to claim 1, wherein the CO converter and the selective oxidizer are arranged in a circumferential direction in the fourth region. The hydrogen production apparatus according to claim 1, further comprising a cooling line that cools the CO shift converter and the selective oxidizer with steam generated by the steam generator. The hydrogen production apparatus according to claim 1, wherein water having a pressure of 500 kPa to 1000 kPa is supplied to the steam generator. Reforming pipe for obtaining a reformed gas containing hydrogen by steam reforming a hydrocarbon oil, a burner for heating the reforming pipe, a steam generator for generating steam required for the steam reforming, and the reformed gas A CO converter for reducing the CO concentration in the gas by a shift reaction, and a hydrogen production apparatus having a selective oxidizer for further reducing the CO concentration in the reformed gas having a reduced CO concentration in the CO converter by a selective oxidation reaction. A fuel cell using the reformed gas produced by the hydrogen production apparatus as a fuel,
A first region which is a vertical columnar region, a second region which is located on an outer peripheral side of the first region and is concentric with the first region, and an outer periphery of the second region; A third region, which is a concentric annular region with the first region, and a fourth region which is concentric with the first region and located on the outer peripheral side of the third region. The first region has the burner, the second region has the reformer tube, the third region has the steam generator, and the fourth region has the CO converter and the selective oxidizer. A fuel cell system comprising: A combustion catalyst is disposed in the second region, and
13. The fuel cell system according to claim 12, further comprising a line for leading an anode off-gas of the fuel cell to the combustion catalyst. 13. The fuel cell system according to claim 12, wherein the burner is a co-firing burner capable of burning an anode off-gas of a fuel cell and hydrocarbon oil, and has a line for guiding the anode off-gas of the fuel cell to the burner.

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