JP2009274919A - External heat type hydrogen production apparatus and fuel cell power system using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve reforming efficiency with a reforming catalyst and to achieve higher performance. <P>SOLUTION: In an external heat type hydrogen production apparatus, in which a raw material gas obtained by mixing a raw material to be reformed and steam is passed through a reforming reaction section heated with external heat, a shift reaction section and a CO oxidation section, and the raw material to be reformed is reformed to hydrogen by a steam reforming reaction and a shift reaction during the passing, a pre-reforming section is disposed on the upstream side of the reforming reaction section 2; this pre-reforming section is made doubly annular; an annular shift reaction section one end of which is made to communicate with the downstream side of the reforming reaction section is disposed in the annular space between the pre-reforming sections; a raw material gas inflow pipe 5 is connected to the upstream side of the pre-reforming section; and the downstream side of the shift reaction section is connected to a reformed gas discharge pipe 25 via the CO selective oxidation section. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an externally heated hydrogen production apparatus for obtaining hydrogen necessary for a small household fuel cell system by using a raw material gas obtained by mixing steam with a reforming raw material gas using, for example, hydrocarbon or aliphatic alcohol And a fuel cell power generation system using the same.

  In this type of conventional externally heated hydrogen production apparatus, for example, the one disclosed in Patent Document 1 is known. In this conventional apparatus, an annular reforming reaction section is provided outside the cylindrical combustion chamber, and the reformed gas generated in the reforming reaction section around the reforming reaction section. A shift reaction part that reduces CO contained therein by an aqueous shift reaction and a CO oxidation part that further reduces CO by oxidizing CO contained in the reformed gas after being processed in this shift reaction part are arranged in a ring shape. It has been configured.

International Publication No. W098 / 00361 Pamphlet

  In the above conventional apparatus, the raw material gas is directly supplied from one axial end of the reforming reaction section formed in an annular shape, and the raw material gas is reformed while flowing in the axial direction and exiting from the other end. Therefore, even if this raw material gas is heated in advance, it takes some time for reforming in the reforming reaction part. Therefore, in order to shorten the reforming time in this part, this modification is necessary. There was a problem that the volume of the quality reaction part was increased.

  Moreover, in the above-mentioned conventional one, since the catalyst of the reforming reaction part, the shift reaction part, and the CO oxidation part is a granular catalyst supported on a granular carrier, the amount of catalyst used is large, There is also a problem that the flow resistance when the raw material gas passes through the granular catalyst is large.

  Since the present invention has been made in view of the above, it is possible to supply the reformed catalyst portion with the pre-reformed raw material gas, and to improve the reforming efficiency in the reforming catalyst portion. Externally-heated hydrogen that can reduce the volume of the catalyst part and achieve high performance and low cost by using a reforming catalyst, shift catalyst, and CO selective oxidation catalyst as an annular honeycomb catalyst. An object of the present invention is to provide a manufacturing apparatus and a fuel cell power generation system using the same.

  In order to achieve the above object, an externally heated hydrogen production apparatus according to the present invention comprises a reforming reaction section, a shift reaction section, and a CO oxidation section in which a reformed raw material gas mixed with steam is heated by external heat. In the externally heated hydrogen production apparatus that reforms into hydrogen by steam reforming reaction and shift reaction during this period, a pre-reforming part is provided upstream of the reforming reaction part, and this pre-reforming part is doubled. And an annular shift reaction part with one end communicating with the downstream side of the reforming reaction part in the annular space between the pre-reforming parts, and the raw material upstream of the pre-reforming part The gas inflow pipe is connected, and the downstream side of the shift reaction section is connected to the reformed gas discharge pipe through the CO selective oxidation section.

  In the apparatus of this configuration, an annular honeycomb catalyst is used for each of the reforming reaction section, the shift reaction section, and the CO selective oxidation section, and in this apparatus, the pre-reforming section has a flow of the source gas from the source gas inflow chamber. It consists of a heat transfer particle and a pre-reforming catalyst that are packed sequentially in the direction, and the shift reaction section is composed of a high-temperature shift catalyst and a low-temperature shift catalyst that are charged in order from the flow direction of the reformed gas from the reforming reaction section. Yes.

  Furthermore, a burner part for supplying sensible heat necessary for the reforming reaction is provided in the inner central part of the reforming reaction part with heat transfer particles interposed between the reforming reaction part and the reforming reaction. An evaporation chamber through which the combustion gas from the burner unit passes is provided around the unit, and an evaporator is installed in the evaporation chamber, and the steam generated in the evaporator is mixed with the reforming source gas to form a source gas. did.

  In addition, a mixer for introducing the oxidizing gas is provided upstream of the CO selective oxidation catalyst, and a flowing water type cooler is provided between the mixer and the CO selective oxidation catalyst, and the downstream side of the cooler is connected to the reforming reaction section. It is the structure connected to the inlet side of the evaporator provided in this evaporation chamber.

  In the fuel cell power generation system according to the present invention, the reformed gas outlet pipe of the externally heated hydrogen production apparatus configured as described above is connected to the fuel supply section of the fuel cell.

  In the external heating type hydrogen production apparatus according to the present invention, the pre-reforming unit is provided upstream of the reforming reaction unit, so that the raw gas is pre-reformed before flowing into the reforming reaction unit. The reforming reaction part can partially reduce the reaction burden and improve the reaction efficiency in the reforming reaction part. The quality reaction part can be miniaturized.

  In addition, since the preliminary reaction part has a double annular shape and a shift reaction part is provided between the preliminary reforming parts, the raw material gas passing through the preliminary reforming part generates heat in the shift reaction part. The generated heat can be efficiently absorbed and the temperature can be raised, and the preliminary reforming action can be satisfactorily performed in this portion.

  In the apparatus of the present invention, by using an annular honeycomb catalyst in each of the reforming reaction section, the shift reaction section, and the CO selective oxidation section, a powdery catalyst is thinly coated on the honeycomb support, All active components can be brought into contact with the reaction gas, and the utilization factor of the catalyst can be dramatically improved as compared with a spherical, granular, or pellet-shaped catalyst. As a result, the amount of catalyst used can be greatly reduced compared to a spherical, granular, or pellet-shaped catalyst, and the cost can be reduced.

  In addition, by making each honeycomb catalyst into an annular shape, the strength of each honeycomb catalyst is improved and the configuration can be simplified, and the number of parts of the reformer can be greatly reduced, resulting in cost reduction. You can plan.

  Further, according to the present invention, the evaporator that generates steam mixed with the reformed gas is provided in the evaporation chamber provided around the reforming reaction section, so that the exhaust heat of the burner section that heats the reforming reaction section is provided. Can be used to improve thermal efficiency.

  An embodiment of an apparatus according to the present invention will be described below with reference to FIG. Needless to say, the present invention is not limited to these embodiments.

  In FIG. 1, reference numeral 1 denotes a cylindrical shape, and a pre-reformation / shift reaction unit formed with the axial direction facing up and down, and 2 denotes a reforming reaction unit disposed on the upper end side of the pre-reformation / shift reaction unit 1. It is.

  In the pre-reformation / shift reaction unit 1, reference numeral 3 denotes an outer cylinder, and the vicinity of the lower end portion in the outer cylinder 3 is partitioned by the first and second partition plates 4 a and 4 b to form the raw material gas inflow chamber 5. The raw material gas inflow pipe 6 is connected to this. The upper end side and the lower end side of the outer cylinder 3 are closed by end plates 7 a and 7 b, and the space between the end plate 7 b on the lower end side and the second partition plate 4 b forming the source gas inflow chamber 5 is between. It is an oxidation chamber 8. Further, the reforming reaction section 2 is provided above the end plate 7 a on the upper end side of the outer cylinder 3. An inner cylinder 9 is provided between the both end plates 7a and 7b in the outer cylinder 3 so as to penetrate them concentrically.

  The first and second intermediate cylinders 10 and 11 are arranged in order from the outside in an annular space between the outer cylinder 3 and the inner cylinder 9 and between the first partition plate 4a and the end plate 7a on the upper end side. Concentric, these intermediate cylinders 10 and 11 form outer, intermediate and inner annular chambers 12, 13 and 14 in order from the outside between the outer cylinder 3 and the inner cylinder 9. At this time, the sectional areas of the outer and inner annular chambers 12 and 14 are substantially the same, and the total sectional area of the outer and inner annular chambers 12 and 14 is the same as the sectional area of the intermediate annular chamber 13. It is almost the same.

  Outer and inner lower ends of the annular chambers 12, 13, and 14 communicate with the source gas inflow chamber 5 through a communication hole 15 provided in the first partition plate 4a. The lower end of the annular chamber 13 communicates with the oxidation chamber 8 through a connecting pipe 16 that penetrates the source gas inflow chamber 5.

  A pre-reformation section having a double annular structure is formed by the outer and inner annular chambers 12 and 14 of the pre-reformation / shift reaction section 1, and about 1 below the annular chambers 12 and 14. The heat transfer particles 17 and 17 are charged in the / 2 portion, and the pre-reforming catalysts 18 and 18 are charged in the upper half portion.

  The intermediate annular chamber 13 is a shift reaction portion provided in an annular space between the outer and inner double annular structure pre-reformers, and is about 1/2 of the lower side. A low temperature shift catalyst 19 is charged in the portion, and a high temperature shift catalyst 20 is charged in the upper half of the upper portion in a vertically divided manner.

  The heat transfer particles 17 and 17 in the preliminary reforming section are in the form of particles, and the preliminary reforming catalysts 18 and 18 are of a pellet type with good heat conduction. Further, both the low temperature and high temperature shift catalysts 19 and 20 have an annular honeycomb structure having a shape along the shape of the intermediate annular chamber 13. Each of the shift catalysts 19, 20 is inserted with a predetermined length in the axial direction through an intermediate support 21 having air permeability in the axial direction.

  In the oxidation chamber 8, a mixer 22 having an oxidizing gas outlet, a cooler 23, and a CO selective oxidation catalyst 24 are arranged in this order from the top toward the connecting pipe 16 side from the intermediate annular chamber 13. The lower end plate 7b is provided with a reformed gas outlet pipe 25 for discharging the gas on the most downstream side of the oxidation chamber 8. The reformed gas outlet pipe 25 is connected to a fuel supply unit of a fuel cell (not shown).

  The mixer 22 is supplied with an oxidizing gas which is air or oxygen. A water supply pipe 26 communicates with the inlet of the cooler 23, and an outlet communicates with an evaporator 28 provided in the reforming reaction section 2 via a communication pipe 27. The outlet pipe of the evaporator 28 is connected to a mixer 6a provided in the raw material gas inflow pipe 6 through a switching valve 28a.

  The CO selective oxidation catalyst 24 is composed of an annular honeycomb catalyst.

  A combustor 29 is mounted in the inner cylinder 9 of the preliminary reforming / shift reaction section 1 with its burner section 29 a facing the upper end side of the outer cylinder 3. The combustor 29 has a double annular structure, and an air supply pipe 30 is communicated with an inner passage, and a burner fuel supply pipe 31 is communicated with an outer annular passage. A spark plug 32 having a tip facing the burner portion 29a is inserted through the center portion. The combustor 29 is a premixed type and has a small configuration with low NOx and low CO.

  As described above, the reforming reaction section 2 is disposed on the upper end side of the preliminary reforming / shift reaction section 1 via the end plate 7a. In this reforming reaction section 2, a bottomed annular cylinder 33 having a shape that closes the opening of the annular section constituted by the outer cylinder 3 and the inner cylinder 9 of the preliminary reforming / shift reaction section 1 is placed on the end plate 7a. It is provided in the state. A combustion chamber 34 facing the burner portion 29 a of the combustor 29 is provided inside the inner cylinder of the bottomed annular cylinder 33. The side and upper side of the bottomed annular cylinder 33 are surrounded by a heat insulating material 35, and the combustion is performed in the space between the outside of the bottomed annular cylinder 33 and the heat insulating material 35 and the inside of the bottomed annular cylinder 33. Heat transfer particles 36 are filled over the outside of the chamber 34. The heat insulating material 35 is provided with an annular evaporation chamber 37 that is substantially concentric with the bottomed annular cylinder 33, and this evaporation chamber 37 is an outer chamber of the bottomed annular cylinder 33 filled with the heat transfer particles 36. Are connected to the exhaust port 39 via other passages, and the combustion gas in the combustion chamber 34 flows from the outside of the combustion chamber 34 to the outside of the bottomed annular cylinder 33. The refrigerant enters the evaporation chamber 37 through the passage 38 through the heat transfer particles 36 filled therein, and is discharged from the evaporation chamber 37 to the exhaust port 39 through another passage. The evaporator 28 is housed in the evaporation chamber 37.

  In the bottomed annular cylinder 33, the first and second intermediate cylinders 40 and 41 have their lower ends abutting against the end plate 7a and their upper ends separated from the bottom surface (ceiling surface) of the bottomed annular cylinder 33. And decorated. A reforming catalyst having a double structure outside and inside the annular honeycomb structure in each of the annular space 42 outside the first intermediate cylinder 40 and the annular space 43 inside the second intermediate cylinder 37. 44 and 44 are internally provided with a gap above and below. The cross-sectional areas of the outer and inner annular spaces 42 and 43 are substantially the same. An annular passage 45 is formed between the first and second intermediate cylinders 40 and 41.

  The outer annular chamber 42 configured in the reforming reaction section 2 and the outer annular chamber 12 outside the preliminary reforming / shifting reaction section 1 are also replaced with the inner annular chamber 43 in the reforming reaction section 2 and the preliminary reforming. The inside of the quality / shift reaction section 1 is provided with an annular chamber 14, and the lower end of the annular passage 45 constituted by the intermediate cylinders 41, 42 in the reforming reaction section 2 and the intermediate portion between the preliminary reforming / shift reaction section 1. The annular chambers 13 are communicated with each other through passages provided in the partition plate 7a.

  In addition, 46 shown in FIG. 1 is a thermocouple which detects the combustion temperature in the combustion chamber 34. Reference numeral 47 denotes a heat insulating material (microtherm: trade name) surrounded by the pre-reformation / shift reaction unit 1 so as to keep it warm.

  In the above configuration, each of the low temperature shift catalyst 19, the high temperature shift catalyst 20, the reforming catalyst 44, and the CO selective oxidation catalyst 24 is an annular honeycomb catalyst as described above. The reason why the annular honeycomb catalyst is used will be described below.

  First, from the viewpoint of performance, the catalytic reaction usually occurs on the surface of the catalyst. When a spherical, granular or pellet type catalyst is used, the catalytically active component present in the catalyst does not contribute to the reaction. On the other hand, in the honeycomb catalyst, since the powdered catalyst is thinly coated (about 100 μm) on the surface of the honeycomb support, all the active components come into contact with the reaction gas. Therefore, the utilization factor of the catalyst can be dramatically improved as compared with the spherical, granular, and pellet type catalysts. As a result, the amount of catalyst used can be greatly reduced compared to a spherical, granular, or pellet catalyst, and the cost can be reduced.

In the case of a reforming catalyst, hydrogen is generated by the reaction of the formula (1), but when the ratio of S / C (steam / carbon) becomes lower than an appropriate value during operation, the carbon shown in the formula (2) A precipitation reaction takes place.
CH ₄ + H ₂ O = 3H ₂ + CO (1)
CH ₄ = 2H ₂ + C (2)

  When a spherical, granular, or pellet-shaped catalyst is used, carbon tends to accumulate in the catalyst layer, and the flow path is clogged, resulting in a large pressure loss and forced shutdown. On the other hand, in the honeycomb catalyst, since the deposited carbon passes through the cell, no pressure or loss occurs.

As an advantage of the honeycomb catalyst, since the outer surface area is large, the reaction active point is increased as compared with the spherical, granular, and pellet shapes. For example, the outer surface area of a honeycomb support of 400 cells / in ² is 3 m ² / L, whereas a spherical support with a diameter of 3 mm is 0.8 m ² / L, and the honeycomb support is about four times as much. . From these points, by using a honeycomb catalyst, it is possible to reduce the amount of the catalyst used and to reduce the size of the reformer by reducing the catalyst volume.

  This point will be described in more detail. In a reformer for a fuel cell, a CO selective oxidation catalyst is indispensable for preventing poisoning of an electrode catalyst by CO. The catalyst is a noble metal, especially platinum. Conventionally, a powder catalyst is formed into a granular or spherical shape, or a granular or spherical carrier is impregnated with a platinum solution. Among these, in the former, since the catalytic reaction occurs on the catalyst surface, platinum inside the catalyst carrier is not used. In the latter, the platinum solution diffuses inside the support during impregnation, and the platinum inside is wasted. On the other hand, by making the catalyst support into a honeycomb, the catalyst is thinly coated only on the surface of the honeycomb support, so that all platinum is used, the utilization rate of the catalyst is increased, and the amount of platinum used is reduced. Less.

  In order to demonstrate the above, the present inventors investigated the activity of a CO selective oxidation catalyst when a powder catalyst is formed into a granular catalyst and when a honeycomb catalyst is used. The measurement method is shown below.

  The CO selective oxidation catalyst was prepared by an ion exchange method. That is, Pt is supported on a powdery mordenite support by an ion exchange method and then dried, and further Fe is supported by an ion exchange method and calcined at 300 ° C. to obtain a 4% Pt-0.5% Fe / mordenite catalyst. It was. The powder catalyst was pressed and crushed to obtain a 1-2 mm powder catalyst. The same 4% Pt-0.5% Fe / mordenite catalyst powder was made into a slurry by adding alumina sol and water, and then coated on a 400-cell cordierite honeycomb to obtain a honeycomb catalyst. At this time, the coating amount of the catalyst is 100 g / L-honeycomb.

The CO selective oxidation activity of the above two types of catalysts was measured by the following method. The reaction tube is filled with 2 cc of catalyst, heated to 300 ° C. in an electric furnace, and reduced by flowing hydrogen. After the reduction, 1% CO-0.5% 0 ₂ -H ₂ balance reaction gas was introduced at a predetermined temperature, and the CO conversion rate was determined from the concentration difference between the inlet and outlet gases. The result is shown in FIG. It can be seen that the honeycomb catalyst exhibits higher activity than the granular catalyst. Further attention should be paid to the amount of Pt used.

  Table 1 compares the amounts of Pt used in the honeycomb catalyst and the granular catalyst in this experiment. As is clear from this result, when the honeycomb catalyst is used, the amount of Pt used can be reduced to 1/5 or less as compared with the granular catalyst. This is because the particulate catalyst does not effectively use Pt inside the particles, whereas the honeycomb catalyst is thinly coated on the surface of the honeycomb support, so most of Pt is effectively used. Estimated. In a hydrogen production apparatus for a fuel cell, this cost has become a bottleneck in practical use. However, as in the present invention, all the catalysts such as a reforming catalyst, a high temperature shift catalyst, a low temperature shift catalyst and a CO selective oxidation catalyst are used in a honeycomb. By using a catalyst, the amount of Pt used can be greatly reduced, which can greatly contribute to cost reduction.

  Further, the advantage of using a honeycomb catalyst is that the pressure loss is small. This greatly contributes to the cost reduction of auxiliary equipment such as pumps because less power is required for the supply of the raw material gas, air, oxygen or water introduced into the reformer. In particular, since reformers such as household fuel cells are required to be further reduced in size and weight, reducing the power of auxiliary devices such as pumps and reducing the size and weight are significant advantages and cost reduction.

  In a DSS-compatible device such as a fuel cell, since the cooling cycle is repeated, the catalyst used requires mechanical strength. However, as a further advantage of using a honeycomb catalyst, the honeycomb support is represented by cordierite in ceramics. Because it is made of a heat-resistant inorganic material, this honeycomb has high mechanical strength, and the shape of the catalyst is monolithic (monolithic), and it is easy to install and take out, making it excellent in terms of usability Is given.

  Conventionally, powdered, spherical, cylindrical, crushed, ring-shaped and the like have been generally used as the contact molded body. However, in the case of powder, the outer surface area is larger than that of the molded body, which is desirable for increasing the catalytic activity. However, when used as a fixed bed, the pressure loss increases, so it is effective only for a fluidized bed. Limited.

  On the other hand, the honeycomb catalyst has many advantages as described above.

  The honeycomb support is preferably made of ceramic or metallic. The ceramic product is an inorganic material such as cordierite, mullite, alumina, zirconia. Further, the honeycomb volume and the number of cells (a numerical value indicating the diameter of the through-hole and the number of holes included in a normal 1 inch square) are determined by the catalyst performance, and can be arbitrarily designed.

  As a method for coating the catalyst powder, it is preferable to use a small amount of a binder in order to improve the binding property with the ceramic or metal as the support. When the binding property is poor, the catalyst powder is peeled off and scattered as dust, so the selection of the binder is particularly important. The honeycomb support is immersed in a slurry liquid in which catalyst powder, a binder and water are mixed, dried and fired at a predetermined temperature.

  Next, the catalyst powder will be described.

  First, in the case of a steam reforming catalyst, at least one selected from Fe, Co, Ni, Ru, Rh, Pd, Ir, and Pt as active components, and Mg, Al, Si, Ti, Zr, Ba, La, and La It is desirable that the catalyst contains at least one carrier component selected from Furthermore, generally by adding an alkali element or a rare earth element to the support component, the solid acidity of the catalyst can be controlled, and carbon deposition can be suppressed.

  The shift reaction catalyst has at least one selected from Cr, Mn, Fe, Co, Ni, Cu, Zn, Ru, Rh, Pd, Ir, and Pt as active components, and Mg, Al, Si, Ti. It is desirable that the catalyst contains at least one carrier component selected from Zr, Ba, and La.

  The selective oxidation catalyst for carbon monoxide is composed of one or a mixture or alloy selected from Pt, Pd, Rh, Ir, Ru, Ni, Co and Fe as active components, and zeolite, alumina as a support A porous carrier such as titania or silica is preferred.

  As a method for producing each catalyst described above, there are a wet method such as a normal impregnation method, a kneading method and an ion exchange method, and a dry method such as a plasma synthesis method, and a production method exhibiting the highest activity may be appropriately selected. .

  Next, the reason why the honeycomb catalyst is formed into an annular shape will be described.

  For the reformer, a reforming catalyst, a high temperature shift catalyst, a low temperature shift catalyst and a CO selective oxidation catalyst are used. The reforming reaction is an endothermic reaction, and the shift reaction and the CO selective oxidation reaction are exothermic reactions. In order for these reactions to occur efficiently, it is important to transfer heat from the outside to the entire catalyst in the reforming catalyst loaded inside the reformer, and to transfer heat to the outside in the shift catalyst. is important.

  When these catalysts are in the form of powder, sphere, cylinder, crushed shape, or ring shape, the catalysts are closely packed with each other, so that heat transfer between the catalysts is good and the temperature tends to be uniform. On the other hand, the honeycomb catalyst has through-holes inside the catalyst, and therefore, heat transfer from the circumferential direction is worse than that of a powdery, spherical, cylindrical, crushed, or ring-shaped catalyst.

  However, according to the experiments by the present inventors, if the honeycomb catalyst is formed in an annular shape and the thickness in the radial direction is less than 25 mm, it is possible to sufficiently transfer the heat from the circumferential direction. It was confirmed that the shift reaction was performed without any problem. In addition, by making the honeycomb catalyst annular, heat from the circumferential direction thereof can be uniformly transmitted to the honeycomb catalyst, and stress acting on the honeycomb catalyst can be dispersed. By doing so, it was found that the number of parts of the reformer could be greatly reduced and contributed to cost reduction.

  Next, the operation of the above configuration apparatus will be described.

  In starting the apparatus of the present invention, first, air is supplied from the air supply pipe 30 of the combustor 29 and burner fuel is supplied from the burner fuel supply pipe 31 at a predetermined pressure, and then the ignition plug electrode 32 is ignited. Combustion at the burner unit 29a is started. The combustion gas in the burner portion 29a passes through the heat transfer particles 36 filled on the outside of the bottomed annular cylinder 33 of the reforming reaction portion 2 and is discharged from the exhaust port 39 through the passage 38 through the annular evaporation chamber 37. During this time, the reforming catalyst 44 housed inside the bottomed annular cylinder 33 of the reforming reaction section 2 is heated from the inside and outside thereof, and the evaporator 28 in the evaporation chamber 37 is heated. .

  Further, in parallel with the combustion in the burner portion 29a, water is supplied from the water supply pipe 26, and water is caused to flow through the cooler 23 to the evaporator 28 disposed in the evaporation chamber 37 to generate steam. At this time, the switching valve 28a is turned off, and the steam is supplied to the mixer 6a with the switching valve 28a turned on in a state where steam at a predetermined temperature is generated from the evaporator 28.

  Combustion in the burner 29a brings the reforming catalyst 44 to a predetermined temperature, the temperature of the steam from the evaporator 28 reaches a predetermined temperature, and the steam flows into the raw material gas from the mixer 6a by turning on the switching valve 28a. Supplied to the tube 6. In this state, the reforming raw material gas is supplied and supplied to the raw material gas inflow chamber 5 as the raw material gas mixed with the steam from the raw material gas inflow pipe 6 to start the operation of the apparatus.

  During operation of this apparatus, the raw material gas that has flowed into the raw material gas inflow chamber 5 has a double annular shape of the pre-reformation / shift reaction unit 1 through the communication hole 15 provided in the first partition plate 4a. It enters the outer and inner annular chambers 12 and 14, and passes through the heat transfer particles 17 and 17 and the pre-reforming catalysts 18 and 18 which are filled in the two chambers in order from the lower side. Thereafter, the reforming reaction part 2 enters the double annular outer and inner annular spaces 42, 43, passes through the reforming catalysts 44, 44 built in both spaces, It reverses in the space of the upper end part of the annular cylinder 33, descends through a passage 45 provided between the spaces 42 and 43 which are double annular in the bottomed annular cylinder 33, and then reserves. A high temperature shift catalyst 20, which enters the middle annular chamber 13 located between the above-described double-structured annular chambers 12, 14 of the reforming / shift reaction section 1, is sequentially installed in the annular chamber 13 from the upper side, It passes through the shift catalyst 19 and enters the oxidation chamber 8, from which it is discharged through the reformed gas outlet pipe 25.

  At this time, the high temperature shift catalyst 20 in the annular chamber 13 in the middle of the pre-reformation / shift reaction unit 1 is heated to a high temperature by a gas flow heated while passing through the reforming catalyst 44 of the reforming reaction unit 2. Then, the low temperature shift catalyst 19 is heated to a lower temperature. The lower heat transfer particles 17 and 17 in the outer and inner annular chambers 12 and 14 of the shift reaction portion 1 are formed by the low-temperature shift catalyst 19 from the inner and outer sides. The pre-reforming catalyst 20 is heated and heated by the high-temperature shift catalyst 20 from the inside and outside thereof.

  In the flow of the raw material gas during operation, the raw material gas that has flowed into the raw material gas inflow chamber 5 passes through the heat transfer particles 17, 17 in the annular chambers 12, 14 inside and outside the preliminary reforming / shift reaction unit 1. The temperature rises by efficiently absorbing the heat heated by the low temperature shift catalyst 19. Next, an endothermic reaction is performed while passing through the upper pre-reforming catalyst 18 so as to efficiently absorb the heat increased in temperature by the exothermic reaction of the high temperature shift catalyst 20, and a part of the raw material gas is reformed. . The heat transfer particles 17 and the pre-reforming catalyst 18 at this time are efficiently conducted to the raw material gas by using a pellet type.

Next, the partially reformed raw material gas undergoes a rapid endothermic reaction while passing from the lower side to the outer side and inner side reforming catalysts 44, 44 of the reforming reaction section 2 in a double annular shape. It is reformed to H ₂ and CO by the steam reforming reaction. Then, the reformed reformed gas passes through both reforming catalysts 44, 44 and then reverses, descends through an annular passage 45 between the reforming catalysts 44, 44, and undergoes preliminary reforming / shifting. The high temperature shift catalyst 20 and the low temperature shift catalyst 19 of the reaction unit 1 are entered. Here, CO is converted into H ₂ and CO ₂ by a shift reaction accompanied by heat generation.

  The reformed gas that has been reacted by the two shift catalysts 20 and 19 in the preliminary reforming / shift reaction section 1 enters the oxidation chamber 8 through the communication pipe 16, and here air (or oxygen introduced from the mixer 22). ). At this time, an amount of air necessary for CO removal is introduced, and is efficiently mixed with the reformed gas by the mixer 22. After that, the cooler 23 cools to the operating temperature of the CO selective oxidation catalyst.

  CO is removed from the reformed gas cooled to a predetermined temperature by the cooler 23 while passing through the CO selective oxidation catalyst 24. The reformed gas (hydrogen) from which the CO has been removed is supplied from the reformed gas outlet pipe 25 to the fuel cell.

  The reforming raw material gas used in the apparatus of the present invention is a hydrocarbon or an aliphatic alcohol, and specifically, city gas, LPG, vaporized kerosene, methane, methanol, ethanol or the like is used. The appropriate value of the mixing ratio S / C (water vapor / carbon) of the reforming raw material gas and water vapor is 2.5 to 3.5, preferably 2.8 to 3.0.

  When the value of S / C increases, the amount of water vapor to be input increases, and therefore a large amount of energy is required to produce the water vapor, so that the system efficiency decreases. Therefore, in the battery system, the supply amount of water vapor is reduced as much as possible. However, when S / C becomes low, C precipitates, so that the actual operation is performed at the preferable value of 2.8 to 3.0.

The dimensions of each part of the device of the present invention shown in FIG. 1 are shown below. In addition, these dimensions show an example in the embodiment, and are not limited to these. That is, as an example, the height L ₁ of the pre-reformation / shift reaction section 1 is about 360 mm, its diameter D ₁ is about 150 mm, the height L ₂ of the reforming reaction section ₂ is about 200 mm, and its diameter is The total volume is about 13.5 liters. The outer diameter of the outer cylinder 3 of the shift reaction unit 1 is 106 mm, and the outer diameters of the intermediate cylinders 10 and 11 are 92 mm and 50 mm, respectively.

  The temperature of each part in the above embodiment is 650 to 750 ° C. for the reforming catalyst part, 350 to 450 ° C. for the high temperature shift catalyst part, and 350 to 450 ° C. for the low temperature shift catalyst part when using a hydrocarbon-based reforming raw material gas. It was 100-150 degreeC in 250-350 degreeC and CO selective oxidation catalyst part.

  Furthermore, the processing amount in this device of the present invention is 3 to 5 LN / min for city gas input and 6 to 14 cc / min for water supply.

It is sectional drawing which shows embodiment of this invention. It is a diagram which shows OC conversion rate with respect to the temperature of a granular catalyst and a honeycomb catalyst.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Preliminary reforming | shifting reaction part, 2 ... Reforming reaction part, 3 ... Outer cylinder, 4a, 4b ... Partition plate, 5 ... Raw material gas inflow chamber, 6 ... Raw material gas inflow pipe, 6a ... Mixer, 7a, 7b ... end plate, 8 ... oxidation chamber, 9 ... inner cylinder, 10, 11 ... intermediate cylinder, 12, 13, 14 ... outer / intermediate / inner annular chamber, 15 ... communication hole, 16 ... communication pipe, 17 ... heat transfer Particles, 18 ... preliminary reforming catalyst, 19 ... low temperature shift catalyst, 20 ... high temperature shift catalyst, 21 ... intermediate support, 22 ... mixer, 23 ... cooler, 24 ... CO selective oxidation catalyst, 25 ... reformed gas outlet pipe , 26 ... water supply pipe, 27 ... communication pipe, 28 ... evaporator, 28a ... switching valve, 29 ... combustor, 29a ... burner section, 30 ... air supply pipe, 31 ... burner fuel supply pipe, 32 ... spark plug, 33 ... bottomed annular cylinder, 34 ... combustion chamber, 35 ... heat insulating material, 36 ... heat transfer particles, 37 ... evaporation chamber, 38 ... communication , 39 ... exhaust port, 40, 41 ... middle tube, 42.43 ... outer-inner annular space, 44 ... reforming catalyst, 45 ... passage, 46 ... thermocouple, 47 ... insulation.

Claims (8)

The raw material gas in which steam is mixed with the reforming raw material is passed through the reforming reaction section, shift reaction section, and CO oxidation section that are heated by external heat, and reformed to hydrogen by the steam reforming reaction and shift reaction between them. In an externally heated hydrogen production system,
A pre-reforming part is provided upstream of the reforming reaction part, and this pre-reforming part is made into a double annular shape, and one end of the reforming reaction part is placed in the annular space between the pre-reforming parts. An annular shift reaction part communicating with the downstream side is provided,
Externally heated hydrogen production characterized in that a raw material gas inflow pipe is connected to the upstream side of the preliminary reforming section, and a downstream side of the shift reaction section is connected to a reformed gas discharge pipe through a CO selective oxidation section. apparatus.   2. The externally heated hydrogen production apparatus according to claim 1, wherein an annular honeycomb catalyst is used for each of the reforming reaction section, the shift reaction section, and the CO selective oxidation section.   The pre-reforming section is composed of heat transfer particles and pre-reforming catalyst that are sequentially filled in the flow direction of the raw material gas from the raw material gas inflow chamber, and the shift reaction section is installed in order from the flow direction of the reformed gas from the reforming reaction section. The externally heated hydrogen production apparatus according to any one of claims 1 and 2, characterized by comprising a high temperature shift catalyst and a low temperature shift catalyst.   The burner section for supplying sensible heat required for the reforming reaction to the inner central part of the reforming reaction section is provided with heat transfer particles interposed between the reforming reaction section and the reforming reaction section. The externally heated hydrogen production apparatus according to any one of 1, 2, and 3.   An evaporation chamber through which the combustion gas from the burner section passes is provided around the reforming reaction section, and an evaporator is provided in the evaporation chamber. Water vapor generated in the evaporator is mixed with the reforming source gas, and the source gas and The externally heated hydrogen production apparatus according to any one of claims 1, 2, 3 and 4.   The externally heated hydrogen production apparatus according to any one of claims 1, 2, 3, 4 and 5, wherein a mixer for introducing an oxidizing gas is provided upstream of the CO selective oxidation catalyst.   A flowing water type cooler is provided between the mixer for inflow of oxidizing gas and the CO selective oxidation catalyst, and the downstream side of this cooler is connected to the inlet side of the evaporator provided in the evaporation chamber of the reforming reaction section. The externally heated hydrogen production apparatus according to claim 6, wherein   A fuel cell power generation system, wherein the reformed gas outlet pipe of the externally heated hydrogen production apparatus according to any one of claims 1 to 7 is connected to a fuel supply unit of the fuel cell.

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