JP4543907B2 - Hydrogen separation membrane device - Google Patents

Description

  The present invention relates to a hydrogen separation membrane device, and more particularly to separation of hydrogen in a gas.

Conventionally, Patent Document 1 discloses a hydrogen separation membrane device in which hydrogen-rich gas is passed through a thin tube having a hydrogen separation membrane, hydrogen is selectively separated from the hydrogen-rich gas by a hydrogen separation membrane, and permeated.
JP-A-8-38863

  However, in the above-described invention, for example, the hydrogen permeation area of the hydrogen permeation membrane area in contact with the hydrogen rich gas is always constant irrespective of the flow rate of the inflowing hydrogen rich gas (reformed gas). When the hydrogen-rich gas flow rate is smaller than when there is a large amount of hydrogen, the concentration of impure gas other than hydrogen contained in the permeate gas becomes high. As the reformed gas flows downstream, the hydrogen concentration in the hydrogen-rich gas decreases and the impurity gas concentration increases, and the impurity gas permeates from the pinholes present in the palladium plating film that forms the hydrogen separation membrane. It is to do.

  Therefore, even when the hydrogen-rich gas flow rate is the smallest in the hydrogen-rich gas flow range assumed by the hydrogen separation membrane device, the thickness of the hydrogen separation membrane is such that the impurity gas other than hydrogen contained in the permeate gas is below the allowable level. It is necessary to thicken. This means that a large amount of expensive hydrogen separation membrane material such as palladium is required, and there is a problem that the cost is increased and the size of the apparatus is increased.

  The present invention was invented to solve such problems, and aims to reduce the cost of the hydrogen separation membrane device and to reduce the size of the device.

In the present invention, a porous body having a plurality of through holes, a hydrogen separation membrane that is formed on the inner peripheral surface of the through holes, separates hydrogen in a gas flowing through the through holes, and permeates hydrogen into the porous body; In the hydrogen separation membrane apparatus comprising: an accumulation unit that accumulates hydrogen along the flow direction of the gas flowing through the through-holes outside the porous body; and a separation unit that separates the accumulation unit into a plurality in the gas flow direction And a control means for controlling the hydrogen separation in the hydrogen separation membrane in the gas flow direction by selectively switching the hydrogen extraction from the separated separation unit based on the operating state of the hydrogen separation membrane device; It is characterized by providing .

A porous body having a plurality of through-holes; and a hydrogen separation membrane formed on the inner peripheral surface of the through-hole, separating hydrogen in the gas flowing through the through-holes and transmitting hydrogen to the porous body. In the hydrogen separation membrane device, an accumulation part for accumulating hydrogen, which is provided outside the porous body along the flow direction of the gas flowing through the through hole, and a separation means for separating the accumulation part into a plurality in the gas flow direction And hydrogen switching at the hydrogen separation membrane in the gas flow direction by selectively switching the switching means based on the gas flow rate. and a that control means to control the.

  According to the present invention, the accumulation part for accumulating the hydrogen separated from the reformed gas is provided outside the porous body, and the accumulation part is divided into a plurality in the flow direction of the reformed gas. A switching unit is provided for each of the divided stacking units, and the switching unit is selectively switched based on the gas flow rate. For example, by closing the switching means of the accumulation section where the carbon monoxide concentration becomes high, carbon monoxide permeation is suppressed in the hydrogen separation membrane that permeates a lot of carbon monoxide, and hydrogen with a high hydrogen concentration is supplied to, for example, a fuel cell Can do. For this reason, it is not necessary to increase the thickness of the hydrogen separation membrane where carbon monoxide permeates a lot, the thickness of the hydrogen separation membrane can be reduced, and the contact area between the reformed gas and the hydrogen separation membrane in the through holes can be increased. . As a result, the cost of the hydrogen separation membrane device can be reduced, and the hydrogen separation membrane device can be reduced in size.

  The configuration of the hydrogen separation membrane device 1 according to the first embodiment of the present invention will be described with reference to the schematic configuration diagram of FIG. FIG. 1 is a cross-sectional view of the hydrogen separation membrane device 1. The hydrogen separation membrane device 1 of this embodiment includes a hydrogen separation unit 20 that separates hydrogen from a reformed gas, and a hydrogen assembly unit 21 in which hydrogen separated from the hydrogen separation unit 20 accumulates.

  The hydrogen separation unit 20 includes a porous porous body 2, a plurality of through holes 3 provided in the porous body 2, and a hydrogen separation membrane 4 provided on the inner peripheral surface of the through hole 3.

  The porous body 2 has a cylindrical shape, and has a plurality of through holes 3 parallel to the central axis of the cylindrical shape, that is, parallel to the longitudinal direction of the porous body 2, and is supplied from a reformer (not shown). The reformed gas that has flowed flows through the through hole 3. The porous body 2 is not limited to a cylindrical shape, and may have other shapes.

  The hydrogen separation membrane 4 is formed by coating the inner peripheral surface of the through hole 3 with, for example, palladium. The thickness of the hydrogen separation membrane 4 is a constant thickness. The hydrogen separation membrane 4 separates hydrogen in the reformed gas, and the hydrogen separated by the hydrogen separation membrane 4 permeates the hydrogen separation membrane 4 and diffuses into the porous body 2 to be described later in a space 10 (10a, 10a, 10b, 10c).

  The hydrogen assembly portion 21 includes a case 11 that forms a space 10 between the porous body 2 and covers the outside of the porous body 2, and a sealing material that separates the space 10 into a plurality of spaces in the central axis direction of the columnar shape. (Separating means, sealing member) 12.

  One end of the case 11 communicates with a reformer (not shown) and constitutes an introduction unit 13 through which reformed gas is introduced from the reformer. The other end constitutes a discharge part 14 in which the remaining reformed gas from which hydrogen has been separated by the hydrogen separation membrane 4 provided in the through hole 3 is discharged from the through hole 3, and the discharge part 14 is not shown, It communicates with a combustion device for burning the reformed gas discharged from the separation membrane device 1. The introduction part 13 is isolated by a collecting part 10a and a sealing material 12a, which will be described later, and the discharge part 14 is isolated by a collecting part 10c and a sealing material 12d, which will be described later.

  In this embodiment, sealing materials 12a, 12b, 12c, and 12d that separate the space 10 into three spaces are provided. The sealing material 12 is the sealing materials 12a, 12b, 12c, and 12d from the upstream side in the flow direction of the reformed gas, and the space defined by the sealing material 12a and the sealing material 12b is a collecting portion (stacking portion) 10a. A space defined by the sealing material 12b and the sealing material 12c is referred to as a collecting portion (stacking portion) 10b, and a space defined by the sealing material 12c and the sealing material 12d is referred to as a collecting portion (stacking portion) 10c. The sealing material 12a is positioned at the uppermost stream in the flow direction of the reformed gas, and prevents the reformed gas introduced into the introducing portion 13 from entering the collecting portion 10a. That is, the hydrogen and the reformed gas accumulated in the collecting portion 10a are prevented from being mixed. Further, the sealing material 12d is located on the most downstream side in the flow direction of the reformed gas so that the reformed gas discharged to the discharge portion 14 is not mixed into the collecting portion 10c.

  In the following, the hydrogen separation part 20 located between the sealing material 12a and the sealing material 12b is the hydrogen separation part 20a, the hydrogen separation part 20 located between the sealing material 12b and the sealing material 12c is the hydrogen separation part 20b, and the sealing material 12c. The hydrogen separation part 20 positioned between the sealing materials 12d will be referred to as a hydrogen separation part 20c, and the subscripts a, b, and c will be attached to the porous body 2 and the like corresponding to the part. It is to be noted that the surface of the hydrogen separation unit 20 in contact with the introduction unit 13 or the discharge unit 14, that is, the end surface of the hydrogen separation unit 20 a that is the most upstream in the reformed gas flow direction, or the end surface of the hydrogen separation unit 20 c that is the most downstream. A separation membrane is formed.

  Further, pipes 15a, 15b, and 15c are connected to the collecting portions 10a, 10b, and 10c, respectively, and the pipes 15a, 15b, and 15c are connected to a hydrogen supply path 16 that supplies accumulated hydrogen to a fuel cell (not shown). The pipes 15a, 15b, and 15c have valves (switching means) 17a, 17b, and 17c, respectively, and supply hydrogen to the hydrogen supply path 16 from the collecting portions 10a, 10b, and 10c by opening and closing the valves 17a, 17b, and 17c. Selectively switch.

  The hydrogen supply path 16 is provided with a carbon monoxide concentration sensor (impure gas detection means) 18 for detecting the carbon monoxide concentration in the hydrogen supply path 16. The carbon monoxide concentration sensor 18 is not limited, and a hydrogen concentration sensor or the like may be used. Further, an impurity gas concentration other than the carbon monoxide concentration may be detected.

  Further, a controller (control means) 50 for controlling the opening / closing operation of the valves 17a, 17b, 17c is provided.

  With the above configuration, it is possible to control the hydrogen separation in the hydrogen separation membranes 4a, 4b, and 4c by controlling the pressures of the collecting portions 10a, 10b, and 10c by controlling the opening and closing of the valves 17a, 17b, and 17c.

  In the hydrogen separation membrane device 1, the reformed gas is introduced from the reformer, and the reformed gas flows through the through holes 3. At this time, hydrogen in the reformed gas is separated by the hydrogen separation membrane 4 provided on the inner peripheral surface of the through-hole 3 from upstream to downstream in the flow direction of the reformed gas in the through-hole 3, and the separated hydrogen is a porous body. 2 and accumulated in the space 10.

  Here, the hydrogen partial pressure in the reformed gas in the through hole 3 with respect to the reformed gas flow direction when the operating load of the fuel cell, that is, the flow rate of the reformed gas is changed will be described with reference to FIG. Here, the operation load of the fuel cell is assumed to be three patterns of high load, medium load, and small load. The hydrogen partial pressure in the reformed gas flowing through the through-hole 3 is such that the hydrogen in the reformed gas is separated by the hydrogen separation membrane 4 and permeates the hydrogen separation membrane 4 and diffuses into the porous body 2. As it gets lower. Further, as the operating load of the fuel cell is small, that is, as the reformed gas flow rate decreases, the hydrogen partial pressure decreases quickly.

  Next, the amount of hydrogen in the permeate gas that permeates the hydrogen separation membrane 4 and the amount of carbon monoxide other than hydrogen when the operating load of the fuel cell is changed will be described with reference to FIG. Here again, the operation load of the fuel cell is assumed to be three patterns of high load, medium load, and low load. As the operating load of the fuel cell is small, that is, as the reformed gas flow rate decreases, the amount of hydrogen that permeates the hydrogen permeable membrane 4 decreases. In addition, the amount of hydrogen in the reformed gas decreases from upstream to downstream in the flow direction of the reformed gas, but the amount of impure gas increases from upstream to downstream as opposed to the amount of hydrogen.

  As described above, when the operation load of the fuel cell is small, that is, when the flow rate of the reformed gas flowing through the hydrogen separation membrane device 1 is small, hydrogen in the permeate gas that permeates the hydrogen separation membrane 4 on the downstream side in the flow direction of the reformed gas. The amount is reduced and the amount of carbon monoxide is increased. That is, when the reformed gas flow rate is small, the reforming is performed by the hydrogen separator 20b or the hydrogen separator 20c located downstream in the flow direction of the reformed gas compared to the hydrogen separator 20a located upstream in the flow direction of the reformed gas. The hydrogen separated from the gas contains a large amount of carbon monoxide. Therefore, in this embodiment, when the operation load of the fuel cell is small, hydrogen separation by the hydrogen separation unit 20b or the hydrogen separation unit 20c is suppressed, and hydrogen having a low carbon monoxide concentration is supplied from the hydrogen separation membrane device 1.

  The space 10 is separated into collecting portions 10a, 10b and 10c by sealing materials 12b and 12c, and the pressure in each collecting portion is adjusted by valves 17a, 17b and 17c. The collecting portions 10a, 10b, and 10c communicate with each other through the porous body 2, but since the pores of the porous body 2 are very small, pressure changes due to opening and closing of the valves 17a, 17b, and 17c are dominant. .

  For example, when the valve 17c is closed, hydrogen from which hydrogen has been separated from the hydrogen separation unit 4c accumulates, and the hydrogen partial pressure in the collecting unit 10c increases. As a result, the hydrogen partial pressure in the porous body 2c of the hydrogen separation unit 20c also increases. Get higher. When the hydrogen partial pressure in the porous body 2c increases, the partial pressure difference from the hydrogen partial pressure in the reformed gas flowing through the through hole 3c decreases, or the pressure of the porous body 2c increases, and the hydrogen permeable membrane 4c Permeation of hydrogen or carbon monoxide can be suppressed.

  Therefore, when all of the valves 17a, 17b, and 17c are open and the reformed gas flow rate is small, the amount of carbon monoxide in the permeate gas increases downstream in the flow direction of the reformed gas. By closing, the amount of permeated gas from the hydrogen permeable membranes 4b and 4c, which is downstream in the flow direction of the reformed gas, is reduced. Thereby, hydrogen having a low carbon monoxide concentration can be supplied to the fuel cell.

  Here, the change of the carbon monoxide concentration in the permeated gas when the operating load of the fuel cell is changed with respect to the open / closed state of the valves 17a, 17b, and 17c of the embodiment will be described with reference to FIG. 4 shows the carbon monoxide concentration when the valves 17a, 17b and 17c are all opened (solid line in FIG. 4), the carbon monoxide concentration when the valves 17a and 17b are opened (broken line in FIG. 4), the valve The carbon monoxide concentration (indicated by a one-dot chain line in FIG. 4) when only 17a is opened is shown.

  When the operating load of the fuel cell is small compared to when the operating load of the fuel cell is large, the amount of carbon monoxide that permeates the hydrogen permeable membrane 4 increases downstream in the flow direction of the reformed gas, so the valve is closed. Increasing the number, for example, opening all of the valves 17a, 17b, and 17c, supplies hydrogen containing a large concentration of carbon monoxide to the fuel cell. Therefore, an upper limit concentration (predetermined concentration) d1 (dotted line in FIG. 4) of the carbon monoxide concentration contained in the hydrogen supplied to the fuel cell is set and included in the hydrogen supplied to the fuel cell according to the load of the fuel cell. The opening and closing of the valves 17a, 17b and 17c is controlled so that the carbon monoxide concentration does not exceed the upper limit concentration d1. Note that the carbon monoxide concentration when the operating load of the fuel cell is the smallest and only the valve 17a is opened is the upper limit concentration d1. The fuel cell operating load α1 when the valves 17a and 17b are opened reaches the upper limit concentration d1, and the carbon monoxide concentration when the valves 17a, 17b and 17c are opened becomes the upper limit concentration d1. The operating load α2 of the fuel cell is set.

  Next, the opening / closing operation of the valves 17a, 17b, 17c by the controller 50 will be described with reference to the flowchart of FIG. This control operation is performed every predetermined time.

  In step S100, the current operation load α of the fuel cell is read and compared with the previous operation load α ′. If the load increases, the process proceeds to step S101, and if the load decreases, the process proceeds to step S102.

  Here, the operation load increase control in step S101 will be described with reference to the flowchart of FIG.

  In step S200, it is determined whether or not the operating load α of the fuel cell is smaller than a preset operating load α1. If the driving load α is smaller than the driving load α1, the process proceeds to step S201. If the driving load α is larger than the driving load α1, the process proceeds to step S202.

  In step S201, since the operating load α of the fuel cell is smaller than the operating load α1, only the valve 17a is opened, the valves 17b and 17c are closed, and the hydrogen separated by the hydrogen separation unit 20a from the collecting unit 10a is supplied to the fuel cell. As a result, hydrogen separation from the hydrogen separation sections 20b and 20c located downstream in the reformed gas flow direction can be suppressed, and hydrogen having a low carbon monoxide concentration can be supplied to the fuel cell. In the case where the reformed gas flow rate is small, the permeation of carbon monoxide in the hydrogen separation membranes 4b and 4c is suppressed by suppressing the hydrogen separation by the hydrogen separation parts 20b and 20c that are relatively high in the carbon monoxide concentration. be able to.

  In step S202, it is determined whether the operating load α of the fuel cell is smaller than the operating load α2. If the fuel cell driving load α is smaller than the driving load α2, that is, the fuel cell driving load α is larger than the driving load α1 and smaller than the driving load α2, the process proceeds to step S203, and the fuel cell driving load α is reached. Is larger than the driving load α2, the process proceeds to step S204.

  In step S203, since the operating load α of the fuel cell is larger than the operating load α1 and smaller than the operating load α2, the valves 17a and 17b are opened, the valve 17c is closed, and the hydrogen separators 20a and 20b are separated from the collecting portions 10a and 10b. The hydrogen separated in step 1 is supplied to the fuel cell. Thereby, permeation of carbon monoxide from the hydrogen separator 20c located downstream in the reformed gas flow direction can be suppressed. Therefore, hydrogen having a low carbon monoxide concentration can be supplied to the fuel cell.

  In step 204, since the operating load α of the fuel cell is larger than the operating load α2, the valves 17a, 17b and 17c are opened, and the hydrogen separated by the hydrogen separators 20a, 20b and 20c from the collecting parts 10a, 10b and 10c is fueled. Supply to battery.

  By controlling the opening operation of the valves 17a, 17b, and 17c by the operation load α of the fuel cell by the above control, the permeation of carbon monoxide from the hydrogen separation membrane 4 is suppressed, and low hydrogen is added to the carbon monoxide concentration. The fuel cell can be supplied. Further, by controlling the opening operation of the valves 17a, 17b, and 17c based on the set operating loads α1 and α2 of the fuel cell, the supply amount of hydrogen can be increased in accordance with an increase in the operating load of the fuel cell. In addition, it is possible to improve the followability of the hydrogen supply with respect to the change in the operation load of the fuel cell.

  Next, the operation load reduction control in step S102 will be described using the flowchart of FIG.

  In step S300, the current open / close state of the valve 17c is confirmed. If the valve 17c is open, the process proceeds to step S301. If the valve 17c is closed, the process proceeds to step S305. In this embodiment, when the operating load α of the fuel cell is reduced, the supply of hydrogen is stopped in the order of the collecting portions 10c and 10b located downstream of the reformed gas flow.

  In step S301, the carbon monoxide concentration sensor 18 detects the carbon monoxide concentration d in hydrogen supplied to the fuel cell and compares it with a preset upper limit concentration d1. When the carbon monoxide concentration d is higher than the upper limit concentration d1, the process proceeds to step S302.

  In step S302, the valve 17c is closed to complete the hydrogen separation from the reformed gas in the hydrogen separation unit 20c, and the permeation of carbon monoxide in the hydrogen separation membrane 4c is suppressed. An increase in the carbon monoxide concentration d in the hydrogen flowing through the hydrogen supply path 16 reduces the operating load of the fuel cell and decreases the reformed gas flow rate, so that the hydrogen separation membrane 4c permeates through the hydrogen separation membrane 4c. This shows that the amount of carbon monoxide increased. Therefore, in step S302, the valve 17c is closed to suppress hydrogen separation in the hydrogen separation unit 20c, and supply of hydrogen from the collecting unit 10c is terminated. As a result, hydrogen having a low carbon monoxide concentration can be supplied to the fuel cell.

  In step S303, the carbon monoxide concentration sensor 18 detects the carbon monoxide concentration d in the hydrogen supplied to the fuel cell, and compares it with a preset upper limit concentration d1. When the carbon monoxide concentration d is higher than the upper limit concentration d1, the process proceeds to step S304.

  In step S304, the valve 17b is closed to complete the hydrogen separation from the reformed gas in the hydrogen separation unit 20b, and the permeation of carbon monoxide in the hydrogen separation membrane 4b is suppressed. As a result, the valve 17b is closed in addition to the valve 17c, hydrogen supply from the collecting portions 10b and 10c is terminated, and hydrogen having a low carbon monoxide concentration can be supplied to the fuel cell.

  On the other hand, if it is determined in step S300 that the valve 17c is closed, the process proceeds to step S305, and it is determined whether the valve 17b is open. If the valve 17b is open, the process proceeds to step S303 and the above control is performed.

  When the operation load α of the fuel cell is reduced by the above control, the valves 17b and 17c are closed based on the carbon monoxide concentration d detected by the carbon monoxide concentration sensor 18, thereby Permeation of carbon monoxide can be suppressed, and hydrogen having a low carbon monoxide concentration can be supplied to the fuel cell. Further, a large amount of hydrogen can be accurately separated from the reformed gas up to the upper limit concentration d1 of the carbon monoxide concentration in the hydrogen supplied to the fuel cell. That is, by closing the valves 17a, 17b, and 17c according to the carbon monoxide concentration, hydrogen separation from the hydrogen separation membranes 4b and 4c that are downstream in the flow direction of the reformed gas can be accurately controlled.

  In this embodiment, when the operation load of the fuel cell is small, the supply of hydrogen from the collecting portions 10c and 10b located downstream in the reformed gas flow direction is completed by closing the valves 17c and 17b. Hydrogen may be supplied from the hydrogen separator 20c that is downstream in the flow direction. That is, when the valves 17a, 17b and 17c are closed, the valves 17a and 17b are closed in this order, and when the valves 17a, 17b and 17c are opened, the valves 17c, 17b and 17a are opened in this order. In this case, by closing the valves 17a and 17b, hydrogen separation from the reformed gas is suppressed in the hydrogen separators 20a and 20b, so that the hydrogen concentration in the reformed gas is increased in the hydrogen separator 20c. Then, hydrogen having a low carbon monoxide concentration can be separated in the hydrogen separator 20c, and hydrogen having a low carbon monoxide concentration can be supplied from the collecting portion 10c to the fuel cell.

  Thereby, even when the load of the fuel cell is abruptly shifted to a high load, hydrogen is separated from the upstream of the reformed gas flow direction by opening the valves 17a and 17b, and hydrogen is supplied from the collecting portions 10a and 10b. The followability of the hydrogen supply with respect to the load fluctuation of the fuel cell can be improved.

  When the hydrogen separation membrane device 1 is started from a predetermined temperature or lower, for example, from a low temperature such as below freezing, the valve 17a is opened so as to supply hydrogen from the collecting portion 10a located upstream in the reformed gas flow direction. Since the temperature of the hydrogen separator 20a located upstream in the reformed gas flow direction is higher than that of the hydrogen separator 20c, hydrogen is sequentially supplied to the fuel cell from the collecting portion 10a upstream in the reformed gas flow direction. . Thereby, hydrogen can be quickly supplied to the fuel cell, and for example, the startup time of the fuel cell system can be shortened.

  In this embodiment, hydrogen is separated from the reformed gas and the separated hydrogen is supplied to the fuel cell. However, the present invention is not limited to this. Further, although the space 10 is separated into three aggregate portions 10a, 10b, and 10c, the number of separation is not limited to this.

  The effect of 1st Embodiment of this invention is demonstrated.

  Here, the change in the concentration of carbon monoxide that permeates the hydrogen separation membrane with respect to the operating load of the fuel cell when the thickness of the hydrogen separation membrane is changed will be described with reference to FIG. When the operating load of the fuel cell is small, that is, when the flow rate of the reformed gas is small, the concentration of carbon monoxide permeating the hydrogen separation membrane increases as the hydrogen separation membrane becomes thinner. Therefore, to reduce the concentration of carbon monoxide that permeates the hydrogen separation membrane, it is conceivable to increase the thickness of the hydrogen separation membrane. However, for example, when palladium is used as the hydrogen separation membrane, the cost increases. . In addition, when the thickness of the hydrogen separation membrane is increased, the hydrogen permeation rate is decreased. For example, when hydrogen separated from the reformed gas is supplied to the fuel cell, In order to increase the contact area between the separation membrane and the reformed gas, the apparatus must be enlarged. In addition, since the increase in the size of the apparatus directly increases the heat capacity, the warming time and the warming energy are increased, the startability of the hydrogen separation membrane device is lowered, and the fuel consumption may be deteriorated due to the increase of the starting energy. is there.

  In this embodiment, the space 10 in which the hydrogen separated from the reformed gas is collected by the hydrogen separation unit 20 is divided into the collection units 10a, 10b, and 10c by the sealing materials 12a, 12b, 12c, and 12d, and the collection units 10a, 10b. 10c is provided with pipes 15a, 15b, 15c and valves 17a, 17b, 17c, and the valves 17a, 17b, 17c are opened and closed according to the operating load of the fuel cell or the carbon monoxide concentration of the hydrogen supply path 16, and the fuel cell The hydrogen separation from the reformed gas by the hydrogen separators 20a, 20b, and 20c is controlled according to the operating load.

  As a result, when the operating load of the fuel cell is small, for example, the valve 17c is closed to suppress hydrogen separation at a location where the carbon monoxide concentration is increased by the hydrogen separator 20c, and the fuel cell has hydrogen with low carbon monoxide concentration. Can be supplied. Therefore, the thickness of the hydrogen separation membrane 4 can be reduced, and the cost can be reduced. In addition, since the thickness of the hydrogen separation membrane 4 can be reduced, the contact area between the reformed gas and the hydrogen separation membrane 4 can be increased, so that the hydrogen separation membrane device 1 can be reduced in size, The cost of the entire hydrogen separation membrane device 1 can be reduced.

  When the operating load of the fuel cell increases, the operating load of the fuel cell opens the valves 17a, 17b, and 17c based on the preset operating loads α1 and α2, so that hydrogen increases as the operating load of the fuel cell increases. The supply amount can be increased, and the followability of the hydrogen supply with respect to the change in the operation load of the fuel cell can be improved.

  Further, when the operating load of the fuel cell is reduced, the valves 17a, 17b, and 17c are closed by the carbon monoxide concentration detected by the carbon monoxide concentration sensor 18, so that hydrogen having a low carbon monoxide concentration is accurately detected in the fuel cell. Can be supplied to.

  Next, the configuration of the hydrogen separation membrane device 60 according to the second embodiment of the present invention will be described with reference to the schematic configuration diagram of FIG. In this embodiment, the hydrogen separator 30 is divided into three parts, and hydrogen separators 30a, 30b, and 30c are formed from the upstream side in the reformed gas flow direction. Further, a ring 31a is provided between the hydrogen separator 30a and the hydrogen separator 30b, and a ring 31b is provided between the hydrogen separator 30b and the hydrogen separator 30c, and the hydrogen separator 30a and the hydrogen separator 30b or hydrogen Gas stirring chambers 37a and 37b are formed between the separation unit 30b and the hydrogen separation unit 30c, respectively. Further, sealing members 32a and 32b are provided between the collecting portion 10a and the collecting portion 10b of the space 10 upstream and downstream of the ring 31a, and between the collecting portion 10b and the collecting portion 10c, sealing is performed upstream and downstream of the ring 31b. Materials 33a and 33b are provided.

  The hydrogen separation unit 30a has substantially the same configuration as the hydrogen separation unit 20a of the first embodiment, and here, different points will be mainly described. The hydrogen separator 30a forms a hydrogen separation membrane on the end face 34 on the ring 31a side, that is, on the end face downstream in the reformed gas flow direction. By forming a hydrogen separation membrane on the end face 34, the area of the hydrogen permeable membrane can be increased, and the contact area between the reformed gas and the hydrogen permeable membrane is increased, so that a large amount of hydrogen separation can be performed. Further, the porous body 2a, the through-hole 3a, and the hydrogen separation membrane 4a of the hydrogen separation unit 20a will be described with the same numbers assigned to the hydrogen separation unit 30a. The hydrogen separators 30b and 30c have the same shape as the hydrogen separator 30a, but the hydrogen separator 30b forms hydrogen separation membranes on both end faces 35a and 35b, and the hydrogen separator 30c is upstream of the reformed gas flow direction. A hydrogen separation membrane is formed on the side end face 36.

  The ring 31 a has, for example, the same outer diameter as that of the hydrogen separator, and has a cylindrical shape with an outer peripheral surface in contact with the inner peripheral surface of the case 11. The reformed gas discharged into the gas agitating chamber 37a formed by the hydrogen separator 30a and the inner peripheral surface of the ring 31a and the hydrogen separator 30b is diffused and mixed in the gas agitating chamber 38a, and then in the hydrogen separator 30b. To be supplied. The ring 31b has the same configuration, and the reformed gas is diffused and mixed by the gas separation chamber 37b formed by the hydrogen separator 30b, the inner peripheral surface of the ring 31b, and the hydrogen separator 30c. The rings 31a and 31b, that is, the gas stirring chambers 37a and 37b are not limited to this shape, and the reformed gas is diffused between the hydrogen separator 30a and the hydrogen separator 30b or between the hydrogen separator 30b and the hydrogen separator 30c. And can be mixed.

  The sealing materials 32a and 32b are provided so that the reformed gas leaks from between the ring 31a and the hydrogen separators 30a and 30b, and the reformed gas does not enter the collecting portions 10a and 10b. Similarly, the sealing materials 33a and 33b are provided so that the reformed gas does not enter the collecting portions 10b and 10c.

  With the above configuration, the reformed gas is once mixed by the gas stirring chambers 37a and 37b, and the reformed gas having a uniform hydrogen concentration is supplied to the hydrogen separators 30b and 30c located downstream of the gas stirring chambers 37a and 37b, respectively. be able to.

  Since the opening / closing operation control of the valves 17a, 17b, and 17c by the controller 50 that extracts hydrogen from the hydrogen separation membrane device 60 is the same control as in the first embodiment, the description thereof is omitted here.

  The rings 31a and 31b are made of a porous material, or the rings 31a and 31b are part of the hydrogen separators 30a, 30b, and 30c, that is, the ring 31a is the hydrogen separator 30a or the hydrogen separator 30b, and the ring 31b is hydrogen. The separator 30b or the hydrogen separator 30c may be integrated. Then, hydrogen separation membranes are also formed on the inner peripheral surfaces and end surfaces (surfaces in contact with 34, 35a, 35b, and 36) of the rings 31a and 31b. Further, the position of the seal is moved (when the ring 31a and the hydrogen separator 30a are integrated, the seal material 32a is moved to the outer periphery of the ring 31a). As a result, the hydrogen separation membrane device 60 can be easily assembled, and the contact area between the hydrogen separation membrane and the reformed gas can be further increased.

  The effect of 2nd Embodiment of this invention is demonstrated.

  Since hydrogen is separated as the reformed gas flowing through the through hole of the hydrogen separation section becomes downstream, the partial pressure of hydrogen in the reformed gas decreases. In addition, when the flow of the reformed gas flowing through the through hole is a laminar flow, it is difficult for the reformed gas to be mixed in the through hole. A hydrogen concentration gradient is generated in which the concentration is low and the hydrogen concentration increases in the vicinity of the central axis of the through hole. Therefore, the hydrogen separation efficiency for separating hydrogen from the reformed gas is lowered on the downstream side of the hydrogen separation unit.

  In this embodiment, the hydrogen separator 30 is divided into hydrogen separators 30a, 30b, 30c, a ring 31a is interposed between the hydrogen separator 30a and the hydrogen separator 30b, and the hydrogen separator 30b and the hydrogen separator A ring 31b is interposed between 30c. As a result, a gas stirring chamber 37a is formed by the hydrogen separator 30a, the ring 31a, and the hydrogen separator 30b, and the reformed gas discharged into the gas stirring chamber 37a is diffused and mixed in the gas stirring chamber 37a. The hydrogen concentration can be made uniform. Therefore, the reformed gas having a uniform hydrogen concentration can be supplied in the hydrogen separation section 30b, which is downstream in the flow direction of the reformed gas, and the hydrogen separation efficiency can be improved. In addition, this can acquire the same effect also in the ring 31b. Further, the hydrogen separation membrane device 1 can be reduced in size, for example, by shortening the length of the hydrogen separation membrane device 1 in the reformed gas flow direction by improving the hydrogen separation efficiency.

  Further, a hydrogen separation membrane is formed on the end surface 34 of the hydrogen separation unit 30a on the ring 31a side and the end surface 35a of the hydrogen separation unit 30b, or on the end surface 36 of the hydrogen separation unit 30c on the ring 31b side and the end surface 35b of the hydrogen separation unit 30b. Thus, the area of the hydrogen separation membrane can be increased, the contact area between the hydrogen separation membrane and the reformed gas can be increased, and the hydrogen separation efficiency can be improved.

  The configuration of the hydrogen separation membrane device 70 of the third embodiment of the present invention will be described with reference to the schematic configuration diagram of FIG. Here, it demonstrates centering on a different location from 2nd Embodiment. In this embodiment, the hydrogen separator 40 is divided / separated into hydrogen separators 40a, 40b, 40c, and the separated / separated hydrogen separators 40a, 40b, 40c are arranged in series so as to be separated from the hydrogen separator 40a and the hydrogen separator. The part 40b is connected by a pipe 45a, and the hydrogen separator 40b and the hydrogen separator 40c are connected by a pipe 45b.

  An introduction unit 13 is formed upstream of the hydrogen separation unit 40a, a discharge unit 41 is formed on one downstream side, an introduction unit 42a is formed on the upstream side of the hydrogen separation unit 40b, and a discharge unit 42b is formed on the one downstream side, An introduction part 43a is formed on the upstream side of the hydrogen separation part 40b, and a discharge part 14 is formed on the downstream side.

  The reformed gas discharged from the hydrogen separation unit 40a is diffused and mixed by the discharge unit 41 or the introduction unit 42a and supplied to the hydrogen separation unit 40b (the discharge unit 41 and the introduction unit 42a constitute a stirring chamber). The reformed gas discharged from the hydrogen separation unit 40b is diffused and mixed by the discharge unit 42b or the introduction unit 43 and supplied to the hydrogen separation unit 40c (the discharge unit 42b and the introduction unit 43 constitute a stirring chamber. ).

  With the above configuration, the reformed gas discharged from the hydrogen separator 40a and the hydrogen separator 40b is diffused, and the reformed gas having a uniform hydrogen concentration is located downstream in the reformed gas flow direction, or The hydrogen can be supplied to the hydrogen separator 40c.

  Since the opening / closing operation control of the valves 17a, 17b, 17c by the controller 50 for taking out hydrogen from the hydrogen separation membrane device 70 is the same control as in the first embodiment, the description thereof is omitted here.

  The effect of the third embodiment of the present invention will be described.

  In this embodiment, in addition to the second embodiment, the hydrogen separators 40a, 40b, and 40c are divided and separated, arranged in series, and connected by the pipe 45a and the pipe 45b. Can be done with a simple layout.

  It goes without saying that the present invention is not limited to the above-described embodiments, and includes various modifications and improvements that can be made within the scope of the technical idea.

  It can be used for a fuel reforming type fuel cell system.

1 is a schematic configuration diagram of a first embodiment of the present invention. It is a map which shows the hydrogen partial pressure in the through-hole of a hydrogen separation membrane apparatus. It is a map which shows the change of the amount of hydrogen and the amount of carbon monoxide in the permeation gas which permeate | transmits a hydrogen separation membrane. It is a map which shows the change of the carbon monoxide density | concentration at the time of changing the driving | running load of a fuel cell. It is a flowchart explaining valve | bulb opening / closing operation | movement of 1st Embodiment of this invention. It is a flowchart which shows the driving | running | working load increase control of 1st Embodiment of this invention. It is a flowchart which shows the driving load increase control of 2nd Embodiment of this invention. It is a map which shows the change of the amount of carbon monoxide which permeate | transmits a hydrogen separation membrane at the time of changing the thickness of a hydrogen separation membrane. It is a schematic explanatory drawing of 2nd Embodiment of this invention. It is a schematic explanatory drawing of 3rd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 60, 70 Hydrogen separator 2, 2a, 2b, 2c Porous body 3, 3a, 3b, 3c Through-hole 4, 4a, 4b, 4c Hydrogen separation membrane 10 Space 10a, 10b, 10c Aggregation part (integration part)
12, 12a, 12b, 12c, 32a, 32b, 33a, 33b Sealing material (seal member)
13, 42a, 43 Introduction part 14, 41, 42b Discharge part 15a, 15b, 15c Piping 17a, 17b, 17c Valve (switching means)
18 Carbon monoxide concentration sensor (impure gas detection means)
20, 20a, 20b, 20c, 30, 30a, 30b, 30c, 40, 40a, 40b, 40c Hydrogen separation part 31a, 31b Ring (dividing means)
37a, 37b Gas stirring chamber (stirring chamber)
50 controller (control means)

Claims (10)

A porous body having a plurality of through holes;
In a hydrogen separation membrane device comprising: a hydrogen separation membrane formed on an inner peripheral surface of the through hole, separating hydrogen in a gas flowing through the through hole, and allowing the hydrogen to permeate the porous body.
A stacking unit for stacking the hydrogen along the flow direction of the gas flowing through the through hole to the outside of the porous body,
Separating means for separating the stacking portion into a plurality of the gas flow direction;
Control for controlling hydrogen separation in the hydrogen separation membrane in the gas flow direction by selectively switching the hydrogen extraction from the plurality of separated separation units based on the operating state of the hydrogen separation membrane device hydrogen separation membrane device, characterized in that it comprises a means. A porous body having a plurality of through holes;
In a hydrogen separation membrane device comprising: a hydrogen separation membrane formed on an inner peripheral surface of the through hole, separating hydrogen in a gas flowing through the through hole, and allowing the hydrogen to permeate the porous body.
An accumulation part that is provided along the flow direction of the gas flowing through the through hole on the outside of the porous body and accumulates the hydrogen;
Separating means for separating the stacking portion into a plurality of the gas flow direction;
A plurality of switching means for selectively switching hydrogen extraction from the plurality of accumulation units separated from each other;
Characterized in that it comprises, said by the switching means selectively switching it, that controls the separation of hydrogen in the hydrogen separation membrane in the flow direction of the gas control means based on operating conditions of the hydrogen separation membrane device A hydrogen separation membrane device. The control means includes an impure gas detection means for detecting an impure gas in hydrogen taken out from the accumulator.
3. The hydrogen separation membrane device according to claim 2, wherein when the concentration of the impure gas is higher than a predetermined concentration, the number of the collecting units that take out the hydrogen is reduced by closing any of the switching units.   4. The hydrogen separation membrane device according to claim 2, wherein when the gas flow rate is increased, the control unit opens the switching unit to increase the number of the collecting units that take out the hydrogen. 5. Said separating means, said porous hydrogen separation membrane device according to claim 1, any one of 4, which is a seal member provided on the outer periphery of the. Wherein the porous body is divided in a direction crossing the flow direction of the gas, from claim 1 and diffusing the gas from the through hole between the porous body, characterized in that it comprises a stirring chamber for mixing The hydrogen separation membrane device according to any one of 5.   The hydrogen separation membrane device according to claim 6, wherein a hydrogen separation membrane is formed on an end face of the porous body divided by the stirring chamber. The stirring chamber is the porous body,
The hydrogen separation membrane apparatus according to claim 6 or 7, wherein the hydrogen separation membrane is formed on a side surface of the stirring chamber. The control means is configured to remove the hydrogen from the accumulation unit located at the uppermost stream in the gas flow direction among the plurality of accumulation units separated at the time of low temperature startup when the temperature of the hydrogen separation membrane device is lower than a predetermined temperature. The hydrogen separation membrane device according to any one of claims 1 to 8, wherein the hydrogen separation membrane device is taken out. In the operation of the hydrogen separation membrane device, the control means preferentially selects from the stacking units located downstream in the gas flow direction among the plurality of stacked units as the gas flow rate decreases. The hydrogen separation membrane device according to any one of claims 1 to 9, wherein the hydrogen is taken out.

Images