JP5150068B2 - Reformer and indirect internal reforming type solid oxide fuel cell - Google Patents

Description

  The present invention relates to a reformer that reforms kerosene to produce a reformed gas containing hydrogen. The present invention also relates to an indirect internal reforming solid oxide fuel cell in which a reformer for reforming kerosene is disposed in the vicinity of the solid oxide fuel cell.

  In a solid oxide fuel cell (hereinafter sometimes referred to as SOFC), a reforming raw material such as kerosene is reformed into a reformed gas containing hydrogen, and the reformed gas is used as fuel for the SOFC. Supplying and generating electricity is performed.

  The SOFC is usually operated at a high temperature of about 550 ° C to 1000 ° C.

The steam reforming reaction used for reforming is a reaction with a very large endotherm, and the reaction temperature is relatively high, requiring a high-temperature heat source. Therefore, an indirect internal reforming SOFC is known in which a reformer is installed in the vicinity of the SOFC (a position that receives heat radiation from the SOFC) and the reformer is heated by radiant heat from the SOFC.
JP 2002-358997 A

  When using higher-order hydrocarbons such as kerosene as reforming raw materials, if hydrocarbon components that have not been reformed are supplied to SOFCs with high operating temperatures, the stability of operation may be impaired due to carbon deposition in SOFCs. . Therefore, it is desired that high-order hydrocarbons such as kerosene be completely converted to C1 compounds (compounds having 1 carbon atom) before being supplied to SOFC. For this reason, it is desired to perform the reforming reaction at a high temperature.

  By the way, in the indirect internal reforming SOFC, the reformer is heated by heat (mainly radiant heat) from the SOFC, and as a result, the reforming catalyst layer is heated. That is, the reformer is heated as a result of the operation of the SOFC. Under such circumstances, it is not easy to adjust the temperature of the reforming catalyst layer, and during normal operation (rated operation or partial load operation), the temperature of the reforming catalyst layer can be increased to completely convert kerosene. However, kerosene may slip in a transient state such as when the load fluctuates (outflow from the reformer without being converted to C1). For example, when increasing the SOFC power load, the flow rate of fuel supplied to the indirect internal reforming SOFC is increased. At this time, the endothermic heat generated by the steam reforming reaction increases, heat transfer to the reforming catalyst layer becomes insufficient, the temperature of the reforming catalyst layer decreases, and unreformed kerosene may flow out of the reformer.

  An object of the present invention is to provide an indirect internal reforming SOFC that prevents the temperature reduction of the reforming catalyst layer and prevents the kerosene from slipping, thereby enabling more stable operation of the SOFC.

The present invention following indirect internal reforming SOFC and an operation method thereof are provided by.

1) a reformer for producing reformed reformed gas of kerosene, the and a solid oxide fuel cell which generates electric power using the reformed gas, the reformer is a solid oxide fuel cell An indirect internal reforming solid oxide fuel cell disposed at a position where it can receive heat radiation from
The reformer is
A catalyst layer having a steam reforming ability for steam reforming kerosene and a partial oxidation reforming ability for partial oxidation reforming of kerosene, and a reaction vessel containing the catalyst layer,
A first supply port for supplying an oxygen-containing gas to an upstream end of the catalyst layer;
A second supply port for supplying an oxygen-containing gas to a portion downstream from an upstream end of the catalyst layer;
The catalyst layer has an upstream catalyst layer and a downstream catalyst layer with respect to the flow of the reformed gas across the gap,
A reformer having a supply port for supplying an oxygen-containing gas to an upstream end of the upstream catalyst layer, and a supply port for supplying an oxygen-containing gas to the gap;
The reaction vessel has two outer wall surfaces facing each other;
A partition partitioning the inside of the reaction vessel into two regions is provided between the two outer wall surfaces,
The two regions communicate with each other at one end of the partition wall,
The upstream catalyst layer is provided between one of the two outer wall surfaces and the partition wall,
Having the downstream catalyst layer between the other outer wall surface and the partition;
A portion where the two regions communicate with each other is a reformer in which the gap is formed,
A solid oxide fuel cell is not disposed on the one outer wall surface side, and a solid oxide fuel cell is disposed on the other outer wall surface side. Indirect internal reforming solid oxide fuel cell battery.

2) a reformer for producing reformed reformed gas of kerosene, the and a solid oxide fuel cell which generates electric power using the reformed gas, the reformer is a solid oxide fuel cell A method of operating an indirect internal reforming solid oxide fuel cell arranged at a position where it can receive heat radiation from
However, the reformer
A catalyst layer having a steam reforming ability for steam reforming kerosene and a partial oxidation reforming ability for partial oxidation reforming of kerosene, and a reaction vessel containing the catalyst layer,
A first supply port for supplying an oxygen-containing gas to an upstream end of the catalyst layer;
A second supply port for supplying an oxygen-containing gas to a portion downstream from an upstream end of the catalyst layer;
The catalyst layer has an upstream catalyst layer and a downstream catalyst layer with respect to the flow of the reformed gas across the gap,
A reformer having a supply port for supplying an oxygen-containing gas to an upstream end of the upstream catalyst layer, and a supply port for supplying an oxygen-containing gas to the gap;
The reaction vessel has two outer wall surfaces facing each other;
A partition partitioning the inside of the reaction vessel into two regions is provided between the two outer wall surfaces,
The two regions communicate with each other at one end of the partition wall,
The upstream catalyst layer is provided between one of the two outer wall surfaces and the partition wall,
Having the downstream catalyst layer between the other outer wall surface and the partition;
A portion where the two regions communicate with each other is a reformer in which the gap is formed,
The solid oxide fuel cell is not disposed on the one outer wall surface side, and the solid oxide fuel cell is disposed on the other outer wall surface side,
The As temperature of the catalyst layer is not less than a predetermined temperature, the oxygen-containing gas supplied to the first supply port flow and the second at least one of the flow rate of the oxygen-containing gas supplied to the supply port of the A method for operating an indirect internal reforming solid oxide fuel cell comprising a step of increasing a flow rate.

  According to the present invention, an indirect internal reforming SOFC is provided that prevents the temperature reduction of the reforming catalyst layer and prevents the kerosene from slipping, thereby enabling more stable operation of the SOFC.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited thereto.

FIG. 1 shows an outline of an example of the indirect internal reforming SOFC of the present invention (however, this example is for reference) . The reformer 1 is disposed between the SOFCs 11-1 and 11-2, and the radiant heat of the SOFC is transmitted to the reformer. The reformer and the SOFC are provided in a container (module container) (not shown) and modularized.

  Hereinafter, air will be described as an example of the oxygen-containing gas. In the present specification, the terms upstream and downstream of the reformer mean upstream and downstream in the flow direction of the reformed gas unless otherwise specified.

  The reformer has a bottomed cylindrical reaction vessel 2. A catalyst layer (reforming catalyst layer) 3 having a steam reforming ability and a partial oxidation reforming ability of kerosene is provided inside the reaction vessel.

  An air supply port (first supply port) 4 is provided at the upstream end of the reaction vessel (the lower end of the drawing in FIG. 1), and air can be supplied from here to the upstream end of the reforming catalyst layer 3. . Similarly, supply ports for supplying kerosene vapor and water vapor are respectively provided at the upstream end of the reaction vessel. These supply ports do not need to be provided independently. For example, a gas mixture in which kerosene vapor, water vapor, and air are mixed in advance may be supplied to one supply port.

  A supply port (second supply port) 5 for supplying air to the reforming catalyst layer portion downstream from the upstream end of the reforming catalyst layer is provided. Here, a plurality (11 in FIG. 1) of second supply ports are provided in the flow direction of the reformed gas.

  A plurality of second supply ports may be provided at the same position in the flow direction of the reformed gas. Here, two second supply ports are provided on the left and right at the same position in the flow direction of the reformed gas. By providing a plurality of second supply ports at the same position in the flow direction of the reformed gas, the distribution of the air supply amount in the plane perpendicular to the flow direction of the reformed gas in the reforming catalyst layer can be reduced. An air supply pipe 6 is connected to each of these second supply ports.

  The first supply port 4 and each air supply pipe 6 are supplied with preheated air as needed from an air supply means (not shown) (compressor, blower, etc.). If air is supplied to the air supply pipe 6, air is supplied from the second supply port 5 to the reforming catalyst layer. Kerosene vapor and water vapor are also appropriately preheated and supplied.

  The flow rate of air supplied to all the supply ports of the first supply port 4 and the second supply port 5 can be adjusted collectively. The air flow rate supplied to the first supply port and the total flow rate of air supplied to the second supply port can also be adjusted independently. In addition, when there are three or more second supply ports, if the air supply pipe 6 is divided into groups and the air flow rate is adjusted for each group, the air flow rate supplied to the second supply port is adjusted for each group. You can also. It is also possible to independently control the flow rate of air flowing through all the second supply ports.

  As the air flow rate adjusting means, a known flow rate adjusting means such as a flow rate adjusting valve or an air blower capable of adjusting the air flow rate can be used.

  The air supply pipe 6 is preferably inserted through the second supply port 5 and into the reforming catalyst layer 3 from the viewpoint of suppressing air from drifting in the vicinity of the reaction vessel wall.

  The reformed gas flows out from the reforming catalyst layer 3, branches and is supplied to the anodes of the SOFCs 11-1 and 11-2. In the figure, A for SOFC indicates an anode, and C indicates a cathode. Air is appropriately preheated and supplied to the cathode, and power generation is performed in the SOFC. The reformer is heated by heat radiation from the SOFC during power generation. Here, the anode and cathode cell outlets are opened in a module container (not shown), and anode off-gas (gas discharged from the anode) burns at the cell outlet, and this combustion heat causes SOFC and further reforming. The vessel is heated.

  Hereinafter, a method for adjusting the temperature of the reforming catalyst layer in the present invention will be described.

  In the present invention, of the flow rate of the oxygen-containing gas supplied to the first supply port and the flow rate of the oxygen-containing gas supplied to the second supply port so that the temperature of the reforming catalyst layer does not fall below a predetermined temperature. At least one of the flow rates is increased (including the case where the oxygen-containing gas flow rate is changed from zero to a certain flow rate).

  For example, it is assumed that a partial load operation of an indirect internal reforming SOFC is performed and only a steam reforming reaction is performed in the reformer by supplying heat from the SOFC. That is, no air is supplied to the reforming catalyst layer and no partial oxidation reforming reaction occurs. If the temperature of the reforming catalyst layer is likely to fall below a predetermined range when the SOFC power load is increased, air is supplied from one or both of the first supply port 4 and the second supply port 5. The temperature of the reforming catalyst layer can be prevented from decreasing due to the heat generated by the partial oxidation reaction.

  Even when autothermal reforming (reforming that performs both partial oxidation reforming reaction and steam reforming reaction) is performed and the temperature of the reforming catalyst layer is likely to fall below a predetermined range, the first supply port and By supplying air from one or both of the second supply ports, it is possible to prevent the temperature of the reforming catalyst layer from decreasing due to heat generated by the partial oxidation reaction.

  If air is supplied from the first supply port, a partial oxidation reforming reaction (kerosene oxidation) occurs from the upstream end of the reforming catalyst layer, and the heat of reaction prevents the temperature reduction of the entire reforming catalyst layer. Can do. If air is supplied from the second supply port, the temperature reduction of the reforming catalyst layer existing downstream of the second supply port can be prevented. If air is supplied from both the first and second supply ports, the reforming catalyst layer existing downstream of the second supply port can be further heated while preventing the temperature of the entire reforming catalyst layer from decreasing. it can.

  If the flow rate of air supplied to the first supply port and the flow rate of air supplied to the second supply port can be adjusted independently, for example, only the downstream side from the second supply port can be heated.

  In the vicinity of the upstream end of the reforming catalyst layer, coking in which carbon is deposited from kerosene vapor may occur depending on conditions. This coking causes catalyst deterioration, but is less likely to occur at lower temperatures. In order to prevent this coking, the temperature of the reforming catalyst layer should be relatively low. Therefore, when it is desired that the temperature of the reforming catalyst layer is relatively low on the downstream side in order to completely convert kerosene while keeping the inlet temperature of the reforming catalyst layer relatively low to prevent coking. There is.

  In such a case, it is effective to reduce the amount of air supplied to the first supply port to zero or a relatively small amount and supply a relatively large amount of air to the second supply port. Therefore, it is preferable that the flow rate of air supplied to the first supply port and the flow rate of air supplied to the second supply port can be adjusted independently.

  When there are a plurality of second supply ports in the flow direction of the reformed gas, the flow rate of air supplied to some second supply ports and the flow rate of air supplied to other second supply ports are independently set. By adjusting, the heating of the reforming catalyst layer can be adjusted more finely.

  In addition, when autothermal reforming is performed by supplying air from one or both of the first supply port and the second supply port, the temperature of the reforming catalyst layer is to be decreased or the temperature increase is suppressed. If desired, the heat generation of the partial oxidation reaction can be suppressed by reducing the air supply amount.

  As a position for measuring the temperature of the reforming catalyst layer, it is preferable to select a position showing the maximum temperature in the reforming catalyst layer. This is because whether or not kerosene is completely converted is greatly influenced by the maximum temperature of the reforming catalyst layer. Since the temperature distribution of the reforming catalyst layer is usually low on the upstream side and rises as it goes downstream, the position showing the highest temperature is usually near the outlet side end of the reforming catalyst layer. In addition, in the case where the air supply amount to the first supply port and the air supply amount to the second supply port can be adjusted separately, the temperature near the upstream end of the reforming catalyst layer is further measured, The air supply amount to the first supply port can be adjusted based on this temperature. Between the upstream end and the downstream end of the reforming catalyst layer, the temperature measurement points can be further increased to monitor the temperature distribution of the reforming catalyst layer. When there are a plurality of second supply ports and the flow rate of air supplied to each of the second supply ports can be adjusted individually or for each group, the temperature of the reforming catalyst layer downstream of each supply port or each group is monitored. By adjusting the flow rate of air supplied to the air, fine temperature control is possible.

  When actually designing the reformer, it is possible to know in advance the temperature distribution of the reforming catalyst layer according to the conditions by preliminary tests and simulations.

  The maximum temperature of the reforming catalyst layer is preferably 650 ° C. or higher from the viewpoint of complete conversion of kerosene. Therefore, for example, this temperature is adopted as the predetermined temperature, and the air supplied to the first supply port and / or the second supply port so that the temperature at the downstream end of the reforming catalyst layer does not fall below this temperature. The flow rate can be increased.

  Specifically, air supply ON / OFF control or P control using a PLC (programmable controller) or a microcomputer board so that the representative value of the measured temperature in the catalyst layer region for supplying air becomes a predetermined temperature. It is desirable to adjust the air flow rate using a control device capable of performing proportional control), PI control (proportional / integral control), PID control (proportional / integral / differential control), or fuzzy control. The parameters required for each control can be obtained by preliminary experiments or simulations.

  The upstream end temperature of the reforming catalyst layer is preferably 550 ° C. or lower from the viewpoint of preventing coking from kerosene.

Hereinafter, other embodiments of the present invention will be described. However, the examples shown in FIGS. 2 to 6 are for reference, and the example shown in FIG. 7 is an example of the present invention.

  FIG. 2 shows another example of the reformer. Moreover, the typical partial expanded sectional view is shown in FIG. The reaction vessel of this reformer has a cylindrical double tube structure formed by an inner tube 2a and an outer tube 2b. The inner tube has a bottomed cylindrical shape. The outer tube covers at least a part of the side wall (cylindrical surface) of the inner tube and forms an air supply flow path together with the side wall of the inner tube.

  The inside of the inner tube is an inner tube portion, and the space between the side wall of the inner tube and the outer tube is an outer tube portion. The inner tube portion and the outer tube portion are partitioned by the side wall of the inner tube. A second supply port 5 is provided on the side wall of the inner tube.

  A reforming catalyst layer 3 having a steam reforming ability and a partial oxidation reforming ability of kerosene is provided inside the inner pipe 2a.

  An air supply pipe 6 is connected to the outer pipe 2b. Air is introduced from the air supply pipe into the air supply flow path of the outer pipe portion, and is supplied from the supply port 5 to the reforming catalyst layer.

  A first supply port 4 is provided at the upstream end of the inner tube (the lower end of the drawing in the drawing), and air is supplied from here. Kerosene vapor and water vapor are also supplied from the upstream end of the inner tube.

  Also in this reformer, the temperature of the reforming catalyst layer can be adjusted as described above. However, in this reformer, although there are five second supply ports 5, the flow rate of the air supplied to each cannot be adjusted independently. The flow rate of air supplied from the first supply port 4 and the total flow rate of air supplied to the five second supply ports, that is, the flow rate of air supplied to the air supply pipe 6 can be adjusted independently. is there. For this purpose, an air flow rate adjusting means may be provided in each of the line for supplying air to the first supply port 4 and the line for supplying air to the air supply pipe 6.

  Although FIG. 2 shows an example in which the reforming catalyst layer is disposed in the inner pipe portion, this is not restrictive. A reforming catalyst layer may be provided in the outer tube portion, and the inner tube portion may be used as an air supply channel. From the viewpoint of heating the reforming catalyst layer with heat transmitted from the SOFC, it is preferable to provide the reforming catalyst layer in the outer tube portion.

  In the example shown in FIG. 2, the opening areas of the plurality of second supply ports are the same, but this is not restrictive. In the reactor having the double tube structure as described above, supply ports having different opening areas may exist among the plurality of second supply ports. An example is shown in FIG.

  The example shown in FIG. 4 is an example in which the size of the second supply port of the reformer shown in FIG. 2 is sequentially increased along the flow direction of the reformed gas. From the second supply ports 5-1 to 5-5, the opening area gradually increases. Thus, the air flow ratio between the second supply ports can be adjusted by changing the opening area of the second supply port.

  In FIG. 5, the outer tube portion that is a flow path for supplying air to the plurality of second supply ports is divided into a plurality of portions, and any of the divided portions is at least one of the plurality of second supply ports. An example of a reformer having a flow path for supplying air is shown.

  In this example, the outer tube has a first portion 2b-1 and a second portion 2b-2, and the space between the first portion of the outer tube and the side wall of the inner tube is the first outer tube portion, and the outer tube A portion between the second portion and the side wall of the inner tube is a second outer tube portion. That is, the outer tube part is divided into two. Air supply pipes 6-1 and 6-2 are connected to the first part 2b-1 and the second part 2b-2 of the outer pipe, respectively. The first outer pipe part is a flow path for supplying air to the second supply ports 5-1, 5-2 and 5-3, and the second outer pipe part is the second supply ports 5-4 and 5 The flow path supplies air to -5.

  By providing an air flow rate adjusting means such as a flow rate adjusting valve in each of the lines supplying air to the air supply tubes 6-1 and 6-2, the flow rate of air supplied to the air supply tube 6-1 and the air supply tube 6 -2 can be independently adjusted.

  Contrary to the example shown in FIG. 5, when the inner pipe portion is a flow path for supplying air to the second supply port (a reforming catalyst layer is provided on the outer pipe portion), the inner pipe portion is partitioned. can do.

  FIG. 6 shows another example of the reformer and the indirect internal reforming SOFC of the present invention. In this reformer, the reforming catalyst layer includes the reforming catalyst layer 3-1 on the upstream side and the catalyst layer 3-2 on the downstream side with respect to the flow of the reformed gas with the gap 7 interposed therebetween. A first supply port 4 that supplies air to the upstream end of the upstream reforming catalyst layer 3-1 is provided, and a second supply port 5 that supplies air to the gap 7 is provided. By supplying air from the second supply port to the gap 7, air is supplied to the upstream reforming catalyst layer 3-2.

  Inside the bottomed cylindrical reaction vessel 2, the reforming catalyst layer 3-1, the void 7 and the reforming catalyst layer 3-2 are arranged in this order in the flow direction of the reformed gas.

  The air gap 7 has the effect of supplying air uniformly into the catalyst layer 3-2 and preventing kerosene slip due to air drifting.

  FIG. 7 shows still another example of the reformer and the indirect internal reforming SOFC of the present invention. In other words, the reformer in this example has a structure in which the reformer shown in FIG.

  The rectangular parallelepiped reaction container 2 has two outer wall surfaces 8-1 and 8-2 facing each other. The outer wall surface 8-2 faces the SOFC 11. The outer wall surface 8-1 is the opposite outer wall surface. Between these two outer wall surfaces, a flat plate-like partition wall 9 that partitions the inside of the reaction vessel into two regions is provided. The outer wall surfaces 8-1 and 8-2 and the partition wall 9 are parallel to each other.

  The two regions communicate with each other at one end of the partition wall, and this portion is a gap 7.

  An upstream reforming catalyst layer 3-1 is disposed between the outer wall surface 8-1 and the partition wall 9, and a downstream catalyst layer 3-2 is disposed between the outer wall surface 8-2 and the partition wall 9. .

  In this example, the SOFC is provided on one side (outer wall 8-2 side) of the reformer, and the SOFC is not provided on the other side (outer wall 8-1 side). By so doing, the temperature of the upstream reforming catalyst layer 3-1 can be made relatively low, and the temperature of the downstream catalyst layer 3-2 can be made relatively high. Therefore, it is suitable for complete conversion of kerosene while preventing coking near the upstream end of the reforming catalyst layer.

[Reformer]
The reformer produces a reformed gas containing hydrogen from kerosene using a steam reforming reaction. In the reformer, a steam reforming reaction can be performed, and autothermal reforming accompanied by a partial oxidation reaction in the steam reforming reaction can be performed. In autothermal reforming, steam reforming is dominant, and therefore the reforming reaction becomes endothermic in overall. Then, heat necessary for the reforming reaction is supplied from the SOFC.

[Reaction vessel]
The shape of the reaction vessel is typically a cylindrical shape (which may be a single tube or a double tube structure) or a rectangular parallelepiped shape, but is not limited thereto. As the reaction vessel, a structure capable of accommodating the catalyst layer can be appropriately selected and used.

  As a material for the reaction vessel, a known material used for the reaction vessel of the reformer, such as stainless steel, can be appropriately used.

(Catalyst layer)
The reforming catalyst layer promotes both a reaction for steam reforming kerosene and a reaction for partial oxidation reforming of kerosene. An autothermal reforming catalyst may be used for the entire reforming catalyst layer, or a part of the reforming catalyst layer may be a steam reforming catalyst and the remaining may be an autothermal reforming catalyst. Alternatively, the steam reforming catalyst layer or autothermal reforming catalyst and the partial oxidation catalyst layer can be alternately stacked.

  From the viewpoint of resistance to oxidation, autothermal reforming is preferable to the steam reforming catalyst.

[Supply port]
The shapes of the first supply port and the second supply port are not limited, and an appropriate shape such as a circle, an ellipse, a rectangle, a square, or a rectangle with a radius can be selected.

  In particular, the size of the second supply port is preferably set such that the reforming catalyst cannot pass therethrough.

  The number of the second supply ports is preferably large when it is desired to uniformly supply the oxygen-containing gas to the reforming catalyst layer. However, considering the strength of the reaction tube, the processing cost, the desired temperature distribution of the reforming catalyst layer, etc. And can be determined as appropriate.

  The first supply port for supplying the oxygen-containing gas to the upstream end of the reforming catalyst layer may be provided in the reaction vessel upstream from the upstream end of the reforming catalyst layer.

  If the second supply port for supplying the oxygen-containing gas to the portion downstream from the upstream end of the reforming catalyst layer is provided in the reaction vessel downstream from the upstream end of the reforming catalyst layer and upstream from the downstream end. Good.

[Oxygen-containing gas]
Examples of the oxygen-containing gas supplied from the first supply port, the oxygen-containing gas supplied from the second supply port, and the oxygen-containing gas supplied to the cathode of the SOFC include gases containing oxygen present in the SOFC system, Air (atmosphere), oxygen-enriched air, and the like can be used as appropriate, but it is preferable to use air that is easily available and has a stable composition.

[Indirect internal reforming SOFC]
The indirect internal reforming SOFC has a reformer and an SOFC. These can be accommodated in one module container and modularized. The reformer is disposed at a position that receives heat radiation from the SOFC. By doing so, the reformer is heated by heat radiation from the SOFC during power generation. In addition, the SOFC can be heated by burning the anode off-gas discharged from the SOFC at the cell outlet.

  The reformer is preferably disposed at a position where direct heat transfer from the SOFC to the outer surface of the internal reformer is possible. Therefore, it is preferable that a shielding object is not substantially disposed between the reformer and the SOFC, that is, a gap is provided between the reformer and the SOFC. Further, it is preferable to shorten the distance between the reformer and the SOFC as much as possible.

  Each fluid supplied to the indirect internal reforming SOFC is appropriately preheated as necessary, and then supplied to the internal reformer or the SOFC.

  As the module container, an appropriate container capable of accommodating the SOFC and the reformer can be used. As the material, for example, an appropriate material having resistance to the environment to be used, such as stainless steel, can be used.

  In particular, when the cell outlet is open in the module container, the module container is preferably airtight so that the inside of the module container and the outside (atmosphere) do not communicate with each other.

  The module container is appropriately provided with a connection port for gas exchange and the like.

[SOFC]
The reformed gas obtained from the reformer is supplied to the anode of the SOFC. On the other hand, an oxygen-containing gas such as air is supplied to the cathode of the SOFC. The SOFC generates heat with power generation, and the heat is radiated from the SOFC to the reformer. Thus, the SOFC exhaust heat is utilized for the endothermic reaction of the reforming reaction. Gas exchange and the like are appropriately performed using piping or the like.

  As the SOFC, known SOFCs of various shapes such as a flat plate type and a cylindrical type can be appropriately selected and employed. In the SOFC, oxygen ion conductive ceramics or proton ion conductive ceramics are generally used as an electrolyte.

  The SOFC may be a single cell, but in practice, a stack in which a plurality of single cells are arranged (in the case of a cylindrical type, sometimes referred to as a bundle, but the stack in this specification includes a bundle) is preferable. Used. In this case, one or more stacks may be used.

[Reforming catalyst]
Any of the steam reforming catalyst, the autothermal reforming catalyst, and the partial oxidation reforming catalyst may be a known catalyst. Examples of steam reforming catalysts include ruthenium and nickel catalysts, and examples of autothermal reforming catalysts include rhodium catalysts. An example of the partial oxidation reforming catalyst is a platinum catalyst.

  Hereinafter, conditions for rated operation will be described for each of steam reforming and autothermal reforming.

The reaction temperature of the steam reforming can be performed, for example, in the range of 450 ° C to 900 ° C, preferably 500 ° C to 850 ° C, and more preferably 550 ° C to 800 ° C. The amount of steam introduced into the reaction system is defined as the ratio of the number of moles of water molecules to the number of moles of carbon atoms contained in the raw material for hydrogen production (steam / carbon ratio), and this value is preferably 1-10, more preferably 1.5-7, more preferably 2-5. When the raw material for hydrogen production is liquid, the space velocity (LHSV) at this time is A / B when the flow rate in the liquid state of the raw material for hydrogen production is A (L / h) and the volume of the catalyst layer is B (L). This value is preferably set in the range of 0.05 to 20 h ⁻¹ , more preferably 0.1 to 10 h ⁻¹ , and still more preferably 0.2 to 5 h ⁻¹ .

  In autothermal reforming, an oxygen-containing gas is added to the raw material in addition to steam. The oxygen-containing gas may be pure oxygen, but air is preferred because of its availability. An oxygen-containing gas can be added so that the endothermic reaction accompanying the steam reforming reaction is balanced, and a heat generation amount capable of maintaining the temperature of the reforming catalyst layer and SOFC or raising the temperature thereof can be obtained. The addition amount of the oxygen-containing gas is preferably 0.005 to 1, more preferably 0.01 to 0.00 as the ratio of the number of moles of oxygen molecules to the number of moles of carbon atoms contained in the raw material for hydrogen production (oxygen / carbon ratio). 75, more preferably 0.02 to 0.6. The reaction temperature of the autothermal reforming reaction is set, for example, in the range of 400 ° C to 900 ° C, preferably 450 ° C to 850 ° C, and more preferably 500 ° C to 800 ° C. When the raw material for hydrogen production is liquid, the space velocity (LHSV) at this time is preferably selected in the range of 0.05 to 20, more preferably 0.1 to 10, and still more preferably 0.2 to 5. The amount of steam introduced into the reaction system is preferably 1 to 10, more preferably 1.5 to 7, and still more preferably 2 to 5 as a steam / carbon ratio.

〔starting method〕
When starting up the indirect internal reforming SOFC of the present invention, for example, the following can be performed. Air heated appropriately using a burner or the like provided separately is supplied to the cathode of the SOFC to heat the SOFC stack, and the reformer is heated by the air discharged from the cathode cell outlet. At this time, a reducing gas can be appropriately passed through the anode and the reforming catalyst layer of the SOFC as necessary. Furthermore, the water vaporizer and the kerosene vaporizer are also appropriately heated so that water vapor and kerosene vapor can be generated.

  When the temperature of the reforming catalyst layer reaches a reformable temperature, reforming is performed by supplying steam and kerosene steam to the reformer. At this time, heat necessary for steam reforming can be generated by supplying air to the reforming catalyst layer and performing autothermal reforming. When the reformed gas is generated, the reformed gas is supplied to the SOFC stack.

  The anode off-gas can be burned at the cell outlet and the heat can further heat the SOFC stack and reformer. Alternatively, the anode off-gas may be taken out of the indirect internal reforming SOFC and burned by a separately provided fuel means, and the SOFC and reformer may be heated using the heat (such as heat exchange with the cathode gas). it can.

  When the SOFC reaches a temperature at which power can be generated, power generation is started, and the SOFC can be further heated by heat generated by the power generation.

  Thus, steady operation (rated operation or partial load operation) becomes possible. When heat is sufficient even if autothermal reforming is not performed in the steady operation, it is possible to stop the supply of air to the reformer and perform reforming only by the steam reforming reaction.

  The indirect internal reforming SOFC of the present invention can be used for, for example, a stationary or moving power generation system and a cogeneration system. The reformer of the present invention can be suitably used for such an indirect internal reforming SOFC.

It is a schematic diagram for explaining the reformer and a reference example of the indirect internal reforming-type SOFC. It is a schematic diagram for demonstrating the reference example of a reformer . FIG. 3 is a schematic partial enlarged view of the reformer of FIG. 2. It is a schematic diagram for demonstrating another reference example of a reformer . It is a schematic diagram for demonstrating another reference example of a reformer . It is a schematic diagram for explaining the reformer and another reference example of the indirect internal reforming-type SOFC. It is a schematic diagram for explaining an example of indirect internal reforming SOFC of the present invention.

Explanation of symbols

1: reformer 2: reaction vessel 2a: inner tube 2b: outer tube 3: reforming catalyst layer 4: first supply port 5: second supply port 6: air supply tube 7: gap (header)
8: Outer wall surface of reaction vessel 9: Partition wall 11: Solid oxide fuel cell

Claims (2)

A reformer kerosene is reformed to produce a reformed gas, wherein and a solid oxide fuel cell which generates electric power using the reformed gas, the thermal reformer from the solid oxide fuel cell An indirect internal reforming solid oxide fuel cell disposed at a position where radiation can be received,
The reformer,
A catalyst layer having a steam reforming ability for steam reforming kerosene and a partial oxidation reforming ability for partial oxidation reforming of kerosene, and a reaction vessel containing the catalyst layer,
A first supply port for supplying an oxygen-containing gas to an upstream end of the catalyst layer;
A second supply port for supplying an oxygen-containing gas to a portion downstream from an upstream end of the catalyst layer;
The catalyst layer has an upstream catalyst layer and a downstream catalyst layer with respect to the flow of the reformed gas across the gap,
A reformer having a supply port for supplying an oxygen-containing gas to an upstream end of the upstream catalyst layer, and a supply port for supplying an oxygen-containing gas to the gap;
The reaction vessel has two outer wall surfaces facing each other;
A partition partitioning the inside of the reaction vessel into two regions is provided between the two outer wall surfaces,
The two regions communicate with each other at one end of the partition wall,
The upstream catalyst layer is provided between one of the two outer wall surfaces and the partition wall,
Having the downstream catalyst layer between the other outer wall surface and the partition;
A portion where the two regions communicate with each other is a reformer in which the gap is formed,
A solid oxide fuel cell is not disposed on the one outer wall surface side, and a solid oxide fuel cell is disposed on the other outer wall surface side. Indirect internal reforming solid oxide fuel cell battery. A reformer kerosene is reformed to produce a reformed gas, wherein and a solid oxide fuel cell which generates electric power using the reformed gas, the thermal reformer from the solid oxide fuel cell A method for operating an indirect internal reforming solid oxide fuel cell disposed at a position where radiation can be received,
However, the reformer,
A catalyst layer having a steam reforming ability for steam reforming kerosene and a partial oxidation reforming ability for partial oxidation reforming of kerosene, and a reaction vessel containing the catalyst layer,
A first supply port for supplying an oxygen-containing gas to an upstream end of the catalyst layer;
A second supply port for supplying an oxygen-containing gas to a portion downstream from an upstream end of the catalyst layer;
The catalyst layer has an upstream catalyst layer and a downstream catalyst layer with respect to the flow of the reformed gas across the gap,
A reformer having a supply port for supplying an oxygen-containing gas to an upstream end of the upstream catalyst layer, and a supply port for supplying an oxygen-containing gas to the gap;
The reaction vessel has two outer wall surfaces facing each other;
A partition partitioning the inside of the reaction vessel into two regions is provided between the two outer wall surfaces,
The two regions communicate with each other at one end of the partition wall,
The upstream catalyst layer is provided between one of the two outer wall surfaces and the partition wall,
Having the downstream catalyst layer between the other outer wall surface and the partition;
A portion where the two regions communicate with each other is a reformer in which the gap is formed,
The solid oxide fuel cell is not disposed on the one outer wall surface side, and the solid oxide fuel cell is disposed on the other outer wall surface side,
The As temperature of the catalyst layer is not less than a predetermined temperature, the oxygen-containing gas supplied to the first supply port flow and the second at least one of the flow rate of the oxygen-containing gas supplied to the supply port of the A method for operating an indirect internal reforming solid oxide fuel cell comprising a step of increasing a flow rate.

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