JP2009149478A - Reformer - Google Patents

Abstract

The present invention provides a reformer that is advantageous for stabilizing the temperature of a harmful component purification section even when operating conditions change or during steady operation.
A reformer includes a reforming unit that generates reformed gas; a harmful component purifying unit that reduces harmful components of the reformed gas; water flowing through a first passage and a second passage. A heat exchanging unit 4 for exchanging heat with the reformed gas flowing through the reforming unit 34 and flowing from the reforming unit 34 toward the harmful component purification unit 5A; water supply units 36 and 27m for supplying water to the first passage 4a of the heat exchanging unit 4; The gas-liquid mixing state of the water before flowing into the first passage 4a of the heat exchange section 4 is detected directly or indirectly, and the cooling capacity and / or harmful component purification section 5A of the first passage 4a of the heat exchange section 4 is detected. And a control unit 500 for controlling the temperature.
[Selection] Figure 1

Description

The present invention relates to a reformer that generates a reformed gas from a fuel material by a reforming reaction.

  Conventionally, a reformer that generates a reformed gas from a fuel material by a reforming reaction has been provided (Patent Document 1). This reformer has a reforming unit that generates reformed gas from a fuel material by a reforming reaction, and a CO shift that reduces carbon monoxide as a harmful component of the reformed gas generated in the reforming unit by a shift reaction. A CO oxidation removal unit that combines carbon monoxide contained in the reformed gas with oxygen through the CO shift unit to reduce it as carbon dioxide, a heat exchange unit, and water vaporized water is supplied to the heat exchange unit And a water supply section. The heat exchange unit has a first passage and a second passage that can exchange heat with each other. Heat exchange is performed between the relatively low temperature water flowing through the first passage and the relatively high temperature reformed gas flowing from the reforming section through the second passage toward the harmful component purification section. As a result, the reformed gas is cooled and supplied to the harmful component purification section. In this way, the temperature of the reformed gas flowing into the harmful component purification unit becomes an appropriate temperature range, so that purification performance in the harmful component purification unit is ensured.

Patent Document 2 discloses a fuel processing device that exchanges heat between the reformed gas flowing in the CO shift section (modified catalyst section) and the raw water used for the reforming reaction in the CO shift section (modified catalyst section). Has been. According to this, the temperature sensor which detects the temperature of a CO shift part (denaturation catalyst part) is provided, and supply_amount | feed_rate of raw material water is controlled based on the temperature of a CO shift part (denaturation catalyst part).
JP 2004-115321 A JP 2004-6093 A

  In the above reformer, the stability of the temperature of the harmful component purification unit may be impaired when the operating conditions of the reformer change due to load fluctuations, or due to disturbances or the like even in steady operation. There is. In this case, the stability of the performance of purifying harmful components may be impaired.

  Therefore, according to Patent Document 2, a temperature sensor that detects the temperature of the CO shift unit (denaturing catalyst unit) is provided, and a method of adjusting the amount of water supplied to the water supply unit based on this temperature signal is adopted. Thus, the CO shift part (modified catalyst part) is stabilized. However, the above-described method is not necessarily sufficient for stabilizing the temperature of the CO shift part (modified catalyst part).

  The present invention has been made in view of the above circumstances, and even when operating conditions change due to load fluctuation or the like, or during steady operation, a CO shift unit, a CO oxidation removal unit, etc. An object of the present invention is to provide a reformer that is advantageous for stabilizing the temperature of the harmful component purification section.

  In order to stabilize the temperature of the harmful component purification unit such as the CO shift unit and the CO oxidation removal unit, the inventor of the harmful component purification unit in the flow path of the reformed gas supplied to the harmful component purification unit. It is important to control the temperature of the heat exchange section located upstream, and in order to control the temperature of the heat exchange section, the state of the water for heat exchange before flowing into the heat exchange section is detected. It was found that it was important to do this, and it was confirmed by a test, and the present invention was completed.

  The reformer according to the present invention includes (i) a reforming unit that generates reformed gas from a fuel raw material by a reforming reaction, and (ii) a harmful component that reduces harmful components of the reformed gas generated in the reforming unit. A component purification unit, and (iii) a first passage and a second passage that can exchange heat with each other, water flowing through the first passage, and reforming from the reforming unit to the harmful component purification unit through the second passage. A heat exchanging unit that cools the reformed gas by supplying heat to the gas and supplying the reformed gas to the harmful component purifying unit; and (iv) a water supply unit that supplies water to the first passage of the heat exchanging unit through the water passage. And (v) a physical quantity relating to the state of water before flowing into the first passage of the heat exchange section is detected directly or indirectly, and the cooling capacity of the first passage of the heat exchange section is detected according to the detected physical quantity. And / or a control unit that controls the temperature of the harmful component purification unit.

  The harmful component purification unit reduces harmful components of the reformed gas generated in the reforming unit. Examples of harmful components include carbon monoxide. Therefore, the harmful component purification unit oxidizes carbon monoxide by the shift reaction between carbon monoxide and water vapor to change it to carbon dioxide, and / or reacts carbon monoxide with oxygen to change it to carbon dioxide. The form is illustrated. Generally, the active temperature range of the harmful component purification unit is lower than the temperature of the reformed gas generated in the reforming unit. Therefore, it is preferable to cool the reformed gas when supplying the reformed gas generated in the reforming unit to the harmful component purification unit. Therefore, the water (liquid phase and / or gas phase) flowing through the first passage of the heat exchange section and the high-temperature reformed gas flowing through the second passage of the heat exchange section are subjected to heat exchange, and harmful through the second passage. The reformed gas flowing toward the component purification unit is cooled.

  Here, in the state of the water in the first passage of the heat exchange section, if the liquid phase is excessive and the cooling capacity of water is too high, the cooling capacity of the first passage of the heat exchange section is too high, and the harmful component purification section. There is a possibility that the temperature of the reformed gas flowing in the gas will be excessively lowered, and the temperature of the harmful component purification unit will be lower than the active temperature range. In this case, the original purification performance of the harmful component purification unit may not be exhibited.

  Then, a control part detects the physical quantity regarding the state of the water before flowing in into the 1st channel | path of a heat exchange part directly or indirectly. Direct detection means directly detecting a physical quantity (temperature, pressure, etc.) relating to the state of water before flowing into the first passage of the heat exchange section. Indirect detection is based on (i) the physical quantity (temperature, pressure, etc.) related to the state of water before flowing into the first passage from the physical quantity (temperature, pressure, etc.) of the water flowing through the first passage of the heat exchange section. Estimate the physical quantity (temperature, pressure, etc.) related to the state of water before flowing into the first passage from the form to be guessed and (ii) the physical quantity (temperature, pressure, etc.) of the water flowing out from the first passage of the heat exchange section Including the form to be performed.

  The “water” before flowing into the first passage of the heat exchange unit may be in a liquid phase, a gas phase, or a gas-liquid mixed fluid in which a gas phase and a liquid phase are mixed. Therefore, the physical quantity relating to the state of water includes the temperature of liquid phase water, the temperature of gas phase water, the pressure of gas phase water, and the pressure of gas-liquid mixed fluid. If the temperature of the water is high, the water changes from the liquid phase to the gas phase, so the ratio of the gas phase increases and the water pressure increases. For this reason, the water pressure can be a parameter that indirectly indicates the temperature of the water, and thus the state of the water (gas-liquid mixed state). Since the latent heat of vaporization (heat of vaporization) of liquid phase water is large, the ratio between the liquid phase and the gas phase affects the cooling ability of water.

  Therefore, the physical quantity relating to the state of water before flowing into the first passage is the physical quantity relating to the state of liquid phase water before flowing into the first passage, the physical quantity relating to the state of gas phase water, and the water in the state of gas-liquid mixing. Can correspond to physical quantities.

  And a control part controls the cooling capacity of the 1st channel | path of a heat exchange part, and / or the temperature of a harmful | toxic component purification | cleaning part according to the detected physical quantity. That is, when it is determined that the ratio of the liquid phase of the water in the first passage of the heat exchange unit is high based on the detected physical quantity (temperature, pressure, etc.) and the cooling capacity of the water is excessively high, the harmful component purification unit May drop excessively. For this reason, the control part can perform the control which reduces the cooling capacity of the 1st channel | path of a heat exchange part, and raises the temperature of a harmful | toxic component purification | cleaning part. Here, in order to reduce the cooling capacity of the first passage, means for reducing the flow rate per unit time of water (liquid phase) supplied to the water supply unit is exemplified.

  Further, when the ratio of the gas phase of the water in the first passage of the heat exchange unit is excessive based on the detected physical quantity (temperature, pressure, etc.) and the cooling capacity is determined to be excessively low, the harmful component purification unit May overheat. For this reason, the control part can perform the control which raises the cooling capacity of the 1st channel | path of a heat exchange part, and lowers the temperature of a harmful | toxic component purification | cleaning part. In order to increase the cooling capacity of the first passage, means for increasing the flow rate of water (liquid phase) supplied to the water supply unit and / or means for heating the water in the water passage with a heating element are exemplified.

  As described above, according to the present invention, the water before flowing into the first passage of the heat exchange unit located upstream of the harmful component purification unit in the flow path of the reformed gas supplied to the harmful component purification unit. A physical quantity related to the state is detected directly or indirectly, and the cooling capacity of the first passage of the heat exchange section and / or the temperature of the harmful component purification section is controlled according to the detected physical quantity. Therefore, even when the operating conditions of the reformer change due to load fluctuations or when disturbances occur in steady operation, harmful component purification that reduces the harmful components of the reformed gas It is advantageous to stabilize the temperature of the part.

  The control unit detects the temperature and / or pressure of the water as a physical quantity related to the state of the water before flowing into the first passage of the heat exchange unit, and cools the first passage of the heat exchange unit according to the detection result. The form which controls the temperature of a performance and / or a harmful | toxic component purification part is illustrated. The temperature of the water before flowing into the first passage of the heat exchange section directly affects the cooling capacity of the first passage, and thus greatly affects the temperature of the harmful component purification section. The temperature and / or pressure of water before flowing into the first passage can be used as a physical quantity relating to the state of water.

  The water supply unit heats water to generate a gas-liquid mixed fluid containing liquid-phase water and gas-phase water, and a gas-liquid mixed fluid generating unit (evaporating unit or the like) connected to the water passage; The form provided with the raw material water supply part (pump etc.) supplied to a mixed fluid generation | occurrence | production part is illustrated. An example is shown in which the water that has been heated in the first passage of the heat exchange section and has flowed out of the first passage is supplied to the reforming section in order to perform the reforming reaction. Depending on the case, you may use the water which flowed out from the 1st channel | path of the heat exchange part for another use.

  When the cooling capacity of the first passage is excessive beyond a predetermined value, the control unit may be configured to reduce the flow rate per unit time of the raw water supplied to the gas-liquid mixed fluid generation unit. When the flow rate of the raw material water is reduced, the amount of liquid phase water flowing through the first passage is reduced, so that the cooling capacity of the first passage is reduced. The predetermined value is appropriately set according to the material of the harmful component purification unit, the use environment of the reformer, and the like.

  Moreover, the form with a detection part which detects directly or indirectly the physical quantity regarding the state of the water before flowing into a 1st channel | path is illustrated for a control part. Examples of the physical quantity related to the water state include the temperature of the water itself and a parameter (such as a pressure exhibited by gas-phase water or a gas-liquid mixed fluid) that indirectly indicates the temperature of the water.

  In addition, the control unit obtains a temperature lowering differential value of the physical quantity related to the temperature of the water before flowing into the first passage, and controls the cooling capacity of the first passage and / or the temperature of the harmful component purification unit based on the temperature lowering differential value. The form to do is illustrated. For example, when the temperature drop differential value of the temperature drop is large, the temperature drop amount of water before flowing into the first passage is large, so that the flow rate of water (liquid phase) supplied to the water supply unit is reduced and / or the water passage It is preferable to heat the water.

Moreover, the form by which the heating element is provided in the water channel is illustrated. In this case, when the cooling capacity of the first passage is excessive beyond a predetermined value, the control unit preferably performs an operation for operating the heating element or an operation for increasing the heat generation amount of the heating element.
In this case, the cooling capacity of the first passage is suppressed from becoming excessively high.

Embodiment 1 of the present invention will be specifically described below with reference to FIG. The reformer according to the present embodiment is applied to a fuel cell system. As shown in FIG.
The reformer 2 includes a reforming unit 34 that generates a reformed gas by a reforming reaction between a reforming fuel (fuel material) and water (steam), and a harmful effect of the reformed gas generated in the reforming unit 34. A harmful component purification unit 5A (carbon monoxide purification unit) for reducing components and a heat exchange unit 4 having a first passage 4a and a second passage 4c that can exchange heat with each other are provided. The reforming unit 34 has a reforming catalyst that promotes the reforming reaction.

  The water supply unit evaporates the raw material water by evaporating the raw material water and the evaporation unit 36 that functions as a gas-liquid mixed fluid generating unit that heats the raw material water in the combustion unit 30 and generates a gas-liquid mixed fluid containing liquid phase water and vapor phase water. A pump 27m (raw material water conveyance source) as a raw water supply unit for supplying to the unit 36 is provided. The gas-liquid mixed fluid (water) generated in the evaporation unit 36 is directed to the heat exchange unit 4 through the water vapor passage 300 (water passage).

  The combustion unit 30 is adjacent to the evaporation unit 36 and the reforming unit 34, and heats the evaporation unit 36 and heats the reforming unit 34. The raw water supplied to the evaporation unit 36 is steamed in the evaporation unit 36. The steamed water flows into the first passage 4 a of the heat exchanging unit 4 through the water vapor passage 300 (water transport passage) connecting the evaporation unit 36 and the heat exchanging unit 4. The water vapor passage 300 is provided with a merging region M1 where the fuel raw material flowing through the fuel passage 62 is joined. Accordingly, in the water vapor passage 300, generally, a gas-liquid mixed fluid in which liquid phase water and gas phase water are mixed flows upstream of the merge region M1. In the water vapor passage 300, downstream of the merge region M <b> 1, a gas-liquid mixed fluid in which liquid phase water, gas phase water, and fuel material for reforming (gas) are mixed passes through the first passage 4 a of the heat exchange unit 4. Flowing. The reformed gas generated in the reforming unit 34 flows through the second passage 4c of the heat exchange unit 4 and travels toward the harmful component purification unit 5A.

  The heat exchanging unit 4 is a relatively low temperature (for example, 70 to 120 ° C.) gas-liquid mixed fluid flowing through the first passage 4a and a relative flow from the reforming unit 34 toward the harmful component purification unit 5A through the second passage 4c. Thus, heat exchange with a hot reformed gas (for example, 300 to 900 ° C.) is performed. As a result, the high-temperature reformed gas immediately after being generated in the reforming unit 34 is cooled by heat exchange in the heat exchange unit 4 and supplied to the harmful component purification unit 5A.

  The harmful component purification unit 5 </ b> A reduces the harmful component (carbon monoxide) of the reformed gas generated by the reforming unit 34. The reformed gas with reduced harmful components is supplied to the fuel cell as an anode gas, and is used for the power generation reaction together with the cathode gas. The harmful component purification unit 5A includes a CO shift unit 5 that oxidizes carbon monoxide by a shift reaction between carbon monoxide and water vapor to change it to carbon dioxide, and a CO that reacts carbon monoxide with oxygen to change it to carbon dioxide. An oxidation removal unit 37 is provided. The CO shift unit 5 generally has a catalyst that promotes the shift reaction. The CO oxidation removing unit 37 generally has a catalyst that promotes an oxidation reaction.

  The temperature sensor 2 detects the temperature T2 in the harmful component purification unit 5A. A detection signal of the temperature sensor 55 is input to the control unit 500. Here, the active temperature range of the harmful component purification unit 5A is lower than the temperature of the reformed gas immediately after being generated by the reforming unit 34 (for example, in the range of more than 300 to 900 ° C.). For example, the activation temperature range of the CO shift unit 5 is in the range of 200 to 300 ° C., and the activation temperature range of the CO oxidation removal unit 37 is in the range of 80 to 300 ° C. However, the activation temperature range is not limited to this.

  In supplying the high-temperature reformed gas generated in the reforming unit 34 to the harmful component purification unit 5A, it is preferable to cool the reformed gas to an appropriate temperature range and supply the reformed gas to the harmful component purification unit 5A. . If the reformed gas is not in the proper temperature range, the oxygen monoxide purification ability in the harmful component purification unit 5A may not be sufficiently exhibited.

  Therefore, according to the present embodiment, water (liquid phase and / or gas phase, lower temperature than the reformed gas) flowing through the first passage 4a of the heat exchange unit 4 and the relative flow through the second passage 4c of the heat exchange unit 4 are used. Heat exchange with the hot reformed gas. As a result, the reformed gas flowing toward the harmful component purification unit 5A via the second passage 4c of the heat exchange unit 4 is cooled in a stage before flowing into the harmful component purification unit 5A.

  Here, if the ratio of the gas phase in the water flowing through the first passage 4a of the heat exchange unit 4 is excessively high, the liquid phase is too small, so that latent heat of vaporization (heat of vaporization) due to water vaporization cannot be expected. As a result, the cooling capacity of water decreases, and the cooling capacity (heat exchange capacity) of the first passage 4a of the heat exchanging section 4 may decrease, and the reformed gas supplied to the harmful component purification section 5A increases excessively. There is a risk of warming.

  On the other hand, if the ratio of the liquid phase of the water flowing through the first passage 4a of the heat exchanging section 4 is excessively high, the latent heat of vaporization (heat of vaporization) due to water increases excessively, and the cooling ability by the first passage 4a becomes excessive. As a result, the temperature of the reformed gas flowing in the harmful component purification unit 5A is lowered, and the harmful component purification unit 5A may be relatively low with respect to the active temperature range. In this case, the purification performance of the harmful component purification unit 5A may be impaired.

  Therefore, according to the present embodiment, as the control law 1, the control unit 500 detects the temperature T2 in the harmful component purification unit 5A by the temperature sensor 55, and supplies the temperature T2 to the combustion unit 30 so that the temperature T2 is in the active temperature range. At least one of the flow rate per unit time of the combustion fuel and combustion air and the number of rotations per unit time of the pump 27m (water transport amount per unit time) is controlled. Thereby, the combustion of the combustion unit 30 is controlled, the ratio of the liquid phase / gas phase in the gas-liquid mixed fluid generated in the evaporation unit 36 is set appropriately, and the temperature T2 becomes the active temperature range of the harmful component purification unit 5A. I have to. As described above, the gas-liquid mixed state (ratio of liquid phase / gas phase) of the water before flowing into the first passage 4a of the heat exchanging unit 4 is appropriately set, and the gas-liquid mixed fluid is set to One passage 4a is supplied. Thereby, the cooling capability (heat exchange capability) by the first passage 4a of the heat exchange unit 4 is maintained well, and the heat exchange amount of the heat exchange unit 4 is maintained well, thereby the purification performance of the harmful component purification unit 5A. Can be fully demonstrated.

  However, when the load fluctuation of the fuel cell or the like occurs and the operation condition of the reformer 2 changes, or when the influence of disturbance is large even in the steady operation, the heat balance of the heat exchange unit 4 or the like is lost. There is a fear. In this case, there is a possibility that the state of water before flowing into the first passage 4a of the heat exchanging unit 4 may change greatly. That is, there is a possibility that the ratio of the liquid phase / gas phase of water changes greatly. As a result, the cooling capacity of the first passage 4a of the heat exchanging unit 4 may fluctuate excessively, and as a result, the stability of the temperature T2 in the harmful component purification unit 5A may be impaired.

  Therefore, according to the present embodiment, the control unit 500 adopts the control law 2 in addition to the control law 1, and the state of water before flowing into the first passage 4a of the heat exchange unit 4 (water in the water vapor passage 300). The cooling ability of the first passage 4a of the heat exchanging unit 4 is controlled according to the state), and consequently the temperature T2 of the harmful component purifying unit 5A is stabilized.

  Further explanation will be given below. That is, the control unit 500 includes a temperature sensor 65 as a detection unit that detects the state of water (water temperature T1) in the merge region M1 of the water vapor passage 300. A detection signal of the temperature sensor 65 is input to the control unit 500. Thereby, the control part 500 can detect the temperature of the water in the merge area M1 of the water vapor passage 300. That is, the control unit 500 determines the cooling capacity of water before flowing into the first passage 4a of the heat exchange unit 4, that is, the water state (liquid phase ratio and / or gas phase ratio) based on the temperature T1. Can be detected.

  Here, when the temperature T1 of the water before flowing into the first passage 4a is relatively low, the ratio of the liquid phase water is large in the state of the water flowing through the merge region M1 of the water vapor passage 300, and the heat The cooling ability of the water (gas-liquid mixed fluid) flowing through the first passage 4a of the exchange unit 4 is high. Further, when the temperature T1 is relatively high, the ratio of liquid-phase water is small in the state of water flowing through the merge region M1 of the water vapor passage 300, the ratio of vapor-phase water is high, and the heat exchange unit 4 The cooling ability of the water (gas-liquid mixed fluid) flowing through the first passage 4a is small. Here, if the ratio of the liquid phase water is excessive, the latent heat of vaporization (heat of vaporization) when the liquid phase water is vaporized is large, so that the cooling ability of the first passage 4a of the heat exchange unit 4 is predetermined. In this case, the temperature of the reformed gas toward the harmful component purification unit 5A is excessively decreased, and the temperature T2 of the harmful component purification unit 5A may be excessively decreased.

  Therefore, when the temperature T1 of the water before flowing into the first passage 4a is relatively low, the controller 500 instructs the pump 27m to reduce the rotational speed (raw material water transport amount) per unit time of the pump 27m. Output. Therefore, the flow rate per unit time of the raw material water supplied to the evaporation unit 36 is reduced. Thereby, while maintaining the combustion of the combustion unit 30, the ratio of liquid phase water in the gas-liquid mixed fluid flowing through the water vapor passage 300 is relatively decreased, and the ratio of gas phase water is relatively increased. As a result, the cooling capacity of the first passage 4a of the heat exchanging unit 4 is suppressed and is made suitable. As a result, the amount of heat exchange between the first passage 4a and the second passage 4c of the heat exchange section 4 is optimized. Therefore, the excessively low temperature of the reformed gas flowing through the second passage 4c is suppressed, and the temperature T2 of the harmful component purification unit 5A is favorably maintained in the active temperature range. In this way, the control unit 500 controls the cooling capacity of the first passage 4a of the heat exchange unit 4 and controls the temperature of the harmful component purification unit 5A to the active temperature range. Therefore, even when the load fluctuation occurs and the operation condition of the reformer 2 changes as described above, or even when the influence of disturbance is large in the steady operation, the purification by the harmful component purification unit 5A is performed. Performance is maintained. When the command value based on the control law 1 and the command value based on the control law 2 are different for the rotation speed of the pump 27m, the control law 2 is prioritized.

  By the way, FIG. 2 shows actual machine data (in the case where the control law 1 is implemented but the control law 2 is not implemented) measured while performing the reforming operation using the actual reformer 2. In FIG. 2, the horizontal axis indicates time. The vertical axis indicates the temperature T1 (characteristic line W1) of the temperature sensor 65 and the temperature T2 (characteristic line W2) of the temperature sensor 55, and the flow rate (characteristic line WA) per unit time of the raw water supplied to the evaporator 36. ).

  When the load of the fuel cell fluctuates, the operating conditions of the reformer 2 are changed accordingly. For example, when the load of the fuel cell is increased and the generated current is increased, the flow rate of the raw water supplied to the evaporation unit 36 is increased. In FIG. 2, the time when the flow rate of the raw material water is increased is assumed to be t1. As shown by the characteristic line W1 in FIG. 2, the temperature T1 of the merge area M1 of the water vapor passage 300 starts to drop at time t2. Time t2 is immediately after time t1 (t2> t1). Further, as shown by the characteristic line W2 in FIG. 2, at the time t3 (t3> t2> t1) when a predetermined time has elapsed from the time t1, the temperature T2 of the harmful component purification unit 5A is lowered due to the influence of the increase in raw material water. start. The time t3 is delayed by a time difference Δt with respect to the time t2. As described above, when the harmful component purification unit 5A cools down excessively, the purification performance of the harmful component purification unit 5A may be impaired.

  By the way, in the control for stabilizing the temperature T2 of the harmful component purification unit 5A, feedback control of the temperature T2 of the harmful component purification unit 5A is not performed based on the temperature T1 of the merge region M1 of the water vapor passage 300, and the temperature T2 is Control that reduces the rotational speed of the pump 82 when the temperature falls is also conceivable.

  Even in this case, if the rotational speed of the pump 82 is decreased to reduce the flow rate of the raw material water supplied to the evaporation unit 36, the excessive temperature decrease of the temperature T2 of the harmful component purification unit 5A is suppressed. However, as can be understood from the characteristic line W2 in FIG. 2, the time t3 at which the temperature T2 of the harmful component purification unit 5A starts to cool is delayed by Δt from the time t2 at which the temperature T1 in the merging zone M1 starts to cool down. . For this reason, the control response for recovering the temperature drop of the temperature T2 of the harmful component purification unit 5A is delayed, and the purification performance in the harmful component purification unit 5A may be impaired. Therefore, as in the above-described embodiment, the temperature of the water before flowing into the first passage 4a of the heat exchange unit 4 located upstream of the harmful component purification unit 5A in the flow path of the reformed gas, that is, the water vapor If the temperature T1 of the junction area M1 of the passage 300 is detected and the amount of water supplied per unit time (number of rotations) by the pump 27m is controlled based on the temperature T1, the response to disturbance can be accelerated, and the harmful component purification unit The temperature T2 of 5A can be maintained well in the active temperature range.

  FIG. 3 shows a second embodiment. Since the present embodiment basically has the same configuration and effect as the first embodiment, FIGS. 1 and 2 are applied mutatis mutandis. Hereinafter, a description will be given centering on portions different from the first embodiment. FIG. 3 shows a flowchart of control executed by the control unit 500. As shown in FIG. 3, it is first determined whether or not the fuel cell is generating power (step S104). If power generation is not in progress (No in step S104), the process proceeds to step S122. If power generation is in progress (Yes in step S104), the signals of the sensors 65 and 55 are read, and the temperature T1 and the temperature T2 are measured (step S106). The noise is removed by filtering the temperature T1 and the temperature T2 (step S108). A target value of the temperature T2 of the harmful component purification unit 5A is obtained by calculation (step S110). PID control is performed on the temperature T2 so that the temperature T2 of the harmful component purification unit 5A becomes a target value (step S112), the rotational speed per unit time of the pump 27m, and the combustion fuel supplied to the combustion unit 30 And control the flow rate of combustion air per unit time. Not only PID control but P control or PI control may be used.

  It is determined whether or not the temperature T1 in the merge region M1 of the water vapor passage 300 is lower than a predetermined temperature TX (eg, 110 ° C.) (step S114).

  Here, step S114 can function as a means for determining the state of the water before flowing into the first passage 4a of the heat exchanging unit 4 (confluence region M1 of the water vapor passage 300). That is, step S114 can function as a means for determining the ratio of the gas phase and / or the liquid phase in the water before flowing into the first passage 4a of the heat exchange unit 4. In other words, in step S114, the cooling capacity of water immediately before being supplied to the first passage 4a of the heat exchanging unit 4 (water flowing through the merge region M1 of the water vapor passage 300) excessively lowers the temperature of the harmful component purification unit 5A. It can function as a means for determining whether or not it is excessive.

  If the temperature T1 is equal to or higher than a predetermined temperature TX (for example, 110 ° C.), the ratio of the water before flowing through the first passage 4a of the heat exchanging section 4 (the confluence region M1 of the water vapor passage 300) is in a gas phase is quite high. Since the ratio of the liquid phase is considerably low, the cooling capacity of the water is not so high, and it is considered that the probability of excessively cooling the harmful component purification unit 5A is low. Further, if the temperature T1 is equal to or lower than a predetermined temperature TX (for example, 110 ° C.), the ratio of the water before flowing through the first passage 4a of the heat exchanging unit 4 (merging region M1 of the water vapor passage 300) is in a liquid phase is high. Since the ratio of the gas phase is low, the cooling ability of the water is high, and it is considered that there is a high probability that the harmful component purification unit 5A is excessively cooled.

  In addition, although the above-mentioned predetermined temperature TX is set to 110 degreeC, for example, it is not restricted to this, According to use environment etc., it is good also as 95 degreeC, 100 degreeC, 115 degreeC, and 120 degreeC. The controller 500 may change the predetermined temperature TX in the summer mode and / or the winter mode.

  As a result of the determination in step S114, if the water temperature T1 in the merge area M1 of the water vapor passage 300 is lower than a predetermined temperature (eg, 110 ° C.) (No in step S114), the cooling capacity of the water is not excessive and therefore harmful. Since there is a low probability that the component purification unit 5A will drop the temperature excessively, it is not necessary to reduce the flow rate per unit time of the raw material water supplied to the evaporation unit 36, so the process proceeds to step S122.

  On the other hand, as a result of the determination in step S114, if the temperature T1 in the merge region M1 of the water vapor passage 300 is less than the predetermined temperature (110 ° C.) (Yes in step S114), the cooling capacity of the water is considerably high. Therefore, there is a high probability that the harmful component purifying unit 5A will excessively lower the temperature, and it is therefore necessary to reduce the flow rate per unit time of the raw water supplied to the evaporation unit 36.

  Therefore, the control unit 500 obtains a temperature lowering differential value (temperature change amount at a reference time (for example, 10 sec)) of the temperature T1 (step S116). If the temperature lowering differential value of the temperature T1 exceeds a predetermined differential value γ (for example, 10 ° C.) (Yes in step S118), the ratio of the liquid phase of the water flowing through the water vapor passage 300 is excessively high, and the temperature T1 rapidly decreases. It is considered that the cooling ability of the first passage 4a of the heat exchange unit 4 becomes excessive, and there is a high possibility that the temperature T2 of the harmful component purification unit 5A is excessively lowered.

  Therefore, the control unit 500 executes the raw material water subtraction process to obtain a flow rate per unit time for subtracting the raw material water supplied to the evaporation unit 36 (step S120). In this case, the subtracted flow rate is obtained according to the temperature T1, the temperature T2, and the like. Further, in consideration of the flow rate per unit time of the gaseous reforming fuel supplied to the merge area M1, the target flow rate per unit time of the raw material water supplied to the evaporation section 36 is obtained by calculation (step S122). As a result, the flow rate per unit time of the water supplied to the evaporator 36 decreases. In the calculation, the relationship between the flow rate of the gaseous reforming fuel supplied to the merge region M1, the temperatures T1, T2, and the like is stored in advance in a predetermined area of the memory of the control device 500 as a map.

Further, a minimum reference value α is set in a predetermined area of the memory of the control unit 500 as an S / C for preventing coking that does not cause coking in the reforming unit 34 during the reforming operation. S / C means the ratio of Steam / Carbon, and the ratio between the number of moles of H ₂ O supplied to the reforming section 34 and the number of moles of C contained in the fuel material supplied to the reforming section 34. It corresponds to. When the S / C ratio is excessively low, the amount of water vapor is excessive with respect to the amount of fuel material, and carbon may be generated in the reforming section 34 to cause coking, which is not preferable.

  The controller 500 obtains α1 as the S / C ratio corresponding to the target flow rate of raw material water obtained by calculation as described above (step S124). The lowest reference value α is compared with α1 (step S126). When α1 (= S / C) is smaller than the minimum reference value α (= S / C) (α> α1), water vapor becomes too small, and coking may occur in the reforming section 34 during the reforming operation. it is conceivable that. For this reason, the correction flow rate β is added to the target flow rate of water obtained by calculation (step S128). A rotation speed command corresponding to the target flow rate obtained by adding the correction flow rate β is output to the pump 27m (step S130).

  Further, as a result of the determination in step S126, when α1 is larger than α (α ≦ α1), coking may occur in the reforming unit 34 even if the flow rate of the raw material water supplied to the evaporation unit 36 is reduced. Therefore, the rotational speed command corresponding to the target flow rate (command to decrease the flow rate per unit time of water carried by the pump 27m) is output to the pump 27m (step S130), and the process returns to the main routine. .

  Thereby, the flow rate per unit time of the raw material water supplied to the evaporation unit 36 is reduced while preventing coking in the reforming unit 34. As a result, the state of the water flowing through the first passage 4a of the heat exchange section 4 (ratio of the liquid phase and the gas phase) is optimized, and consequently the gas-liquid mixture state of the water flowing through the first passage 4a of the heat exchange section 4 is optimized. Let As a result, excessive cooling capacity in the heat exchange unit 4 is suppressed. As a result, the temperature T2 of the harmful component purification unit 5A is maintained in the activation temperature range. As a result, the carbon monoxide reduction effect at the temperature T2 of the harmful component purification unit 5A is obtained well, and the reformed gas is purified well. As described above, according to the present embodiment, according to the gas-liquid mixed state of water (liquid / phase ratio of water) before flowing into the first passage 4a of the heat exchange unit 4, the heat exchange unit 4 The cooling ability of the first passage 4a and / or the temperature of the harmful component purification unit 5A is controlled.

  Since this embodiment has basically the same configuration and operation effects as the first and second embodiments, FIGS. 1 to 3 are applied mutatis mutandis. In the first and second embodiments, the control unit 500 detects, as the control law 1, the temperature T2 in the harmful component purification unit 5A by the temperature sensor 55, and sets the combustion unit 30 so that the temperature T2 is in the active temperature range. The flow rate per unit time of the supplied combustion fuel and combustion air and the rotation speed per unit time of the pump 27m are controlled. Further, in the first and second embodiments, the control unit 500 detects the water state (water temperature T1) in the merge area M1 of the water vapor passage 300 with the temperature sensor 65 as the control law 2, and based on the temperature T1, the pump The number of rotations per unit time of 27 m (corresponding to the amount of water transported) is controlled.

  However, according to the present embodiment, the control law 1 is not executed, but the control law 2 is executed.

  FIG. 4 shows a fourth embodiment. The present embodiment basically has the same configuration and operational effects as the first embodiment. Hereinafter, a description will be given centering on portions different from the first embodiment. According to the present embodiment, the pressure sensor 65p is provided in the water vapor passage 300 from the evaporator 36 to the heat exchanger 4. The detection signal of the pressure sensor 65p is input to the control unit 500. The pressure sensor 65p detects the pressure of the water flowing through the water vapor passage 300 (a gas-liquid mixed fluid in which liquid phase water and gas phase water are mixed). A high pressure means that the water vapor phase ratio is high, the water temperature T1 in the water vapor passage 300 is high, and the water vapor phase ratio in the water vapor passage 300 is high. . Here, the ratio of the pressure value measured by the pressure sensor 65p, the temperature T1, and the gas phase is obtained through experiments or the like, and is stored in advance in the memory of the control unit 500.

  The controller 500 obtains the temperature T1 of the water in the water vapor passage 300 based on the signal from the pressure sensor 65p, and detects the state of the water (the ratio of the gas phase and / or the liquid phase). Thus, the control unit 500 indirectly detects the state of water before flowing into the first passage 4a of the heat exchange unit 4, and outputs a command to adjust the rotational speed per unit time of the pump 27m. Thereby, the control part 500 controls the cooling capacity of the 1st channel | path 4a of the heat exchange part 4, and / or the temperature of the harmful | toxic component purification | cleaning part 5A similarly to the above-mentioned Example.

  FIG. 5 shows a fifth embodiment. The present embodiment basically has the same configuration and function as the first embodiment. Hereinafter, a description will be given centering on portions different from the first embodiment. According to the present embodiment, the heating element 330 is provided in the water vapor passage 300 from the evaporator 36 to the first passage 4 a of the heat exchange unit 4. The heating element 330 heats water flowing through the water vapor passage 300, and an electric heater and / or a gas combustion heater are exemplified.

  When the temperature T1 of the water before flowing into the first passage 4a (water vapor passage 300) is excessively low, the control unit 500 turns on the heating element 330 or increases the heat generation amount of the heating element 330 that is turned on. Command to output. As a result, in the state of water flowing through the merge area M1 of the water vapor passage 300, the ratio of vapor-phase water is increased, and the cooling ability of the water (gas-liquid mixed fluid) flowing through the first passage 4a of the heat exchange unit 4 is increased. Get smaller. For this reason, it is suppressed that the temperature of the reformed gas toward the harmful component purification unit 5A is excessively decreased, and the possibility that the temperature T2 of the harmful component purification unit 5A is excessively decreased is also suppressed.

  FIG. 6 shows a sixth embodiment. The present embodiment basically has the same configuration and action hardening as the first embodiment. Hereinafter, a description will be given centering on portions different from the first embodiment. According to the present embodiment, the cooling of the first passage 4a of the heat exchange unit 4 according to the state of the water after flowing out of the first passage 4a of the heat exchange unit 4 (the ratio of the liquid phase / gas phase of water). The temperature of the performance and / or harmful component purification unit 5A is controlled. Further explanation will be given below. That is, the control unit 500 includes a temperature sensor 65a as a detection unit that detects the temperature T1a of water. The temperature T1a is a temperature before flowing out from the first passage 4a of the heat exchange unit 4 and flowing into the reforming unit 34.

  A detection signal of the temperature sensor 65 a is input to the control unit 500. Accordingly, the control unit 500 indirectly detects the temperature of the water before flowing into the first passage 4a of the heat exchange unit 4 (the state of the water before flowing into the first passage 4a) based on the temperature T1a. be able to. That is, the control unit 500 can indirectly detect the state of water (liquid phase ratio or gas phase ratio) before flowing into the first passage 4a of the heat exchange unit 4.

  Here, when the temperature T1a is relatively low, in the water before flowing into the first passage 4a of the heat exchange unit 4, the ratio of liquid phase water is high and the cooling capacity of water is relatively high. Become. Moreover, when temperature T1a is relatively high, in the water before flowing into the 1st channel | path 4a of the heat exchange part 4, the ratio of gaseous water will be high and the cooling capacity of water will be relatively low. .

  Therefore, if the ratio of the liquid phase water is excessive, the cooling capacity of the first passage 4a of the heat exchange unit 4 is excessive than a predetermined value, and at this time, the temperature of the harmful component purification unit 5A is excessively decreased. However, it becomes lower than the activation temperature range. Therefore, the control unit 500 outputs a command to the pump 27m to reduce the rotational speed (raw material water transport amount) per unit time of the pump 27m. Therefore, the flow rate per unit time of the raw material water supplied to the evaporation unit 36 is reduced. Thereby, in the gas-liquid mixed fluid flowing through the water vapor passage 300, the ratio of the liquid phase water is relatively decreased, and the ratio of the vapor phase water is relatively increased. As a result, the cooling capacity of the first passage 4a of the heat exchange unit 4 is optimized. As a result, the amount of heat exchange between the first passage 4a and the second passage 4c of the heat exchange section 4 is optimized. Accordingly, the excessively low temperature of the reformed gas flowing through the second passage 4c is suppressed, and the temperature T2 of the harmful component purifying unit 5A is favorably maintained.

  FIG. 7 shows a seventh embodiment. The present embodiment basically has the same configuration and action hardening as the first embodiment. The present embodiment basically has the same configuration and operational effects as the first embodiment. Hereinafter, a description will be given centering on portions different from the first embodiment. According to the present embodiment, as shown in FIG. 7, the control unit 500 includes the temperature sensor 65b as a detection unit that detects the temperature T1b of the water flowing through the first passage 4a inside the heat exchange unit 4. When the temperature T1b is relatively low, the ratio of liquid phase water in the water before flowing into the first passage 4a of the heat exchange unit 4 is large. When the ratio of the liquid phase water is excessive, the cooling capacity of the first passage 4a of the heat exchange unit 4 is excessive than a predetermined value. At this time, the temperature T2 of the harmful component purification unit 5A is excessively decreased. There is a possibility that the temperature becomes lower than a predetermined temperature. Therefore, the control unit 500 outputs a command to the pump 27m to reduce the rotational speed (raw material water transport amount) per unit time of the pump 27m. As a result, as described above, the ratio of liquid phase water in the gas-liquid mixed fluid flowing through the water vapor passage 300 is relatively decreased, and the ratio of gas phase water is relatively increased. As a result, the cooling capacity (heat exchange amount) of the first passage 4a of the heat exchange unit 4 is optimized. Accordingly, the excessively low temperature of the reformed gas flowing through the second passage 4c is suppressed, and the temperature T2 of the harmful component purifying unit 5A is favorably maintained. Therefore, even when the operating conditions change as described above, the purification performance by the harmful component purification unit 5A is maintained.

  FIG. 8 shows an eighth embodiment. The present embodiment basically has the same configuration and operational effects as the first embodiment. As shown in FIG. 8, the fuel cell 1 is formed by assembling a plurality of membrane electrode assemblies 13 that sandwich a solid polymer membrane 10 having proton conductivity between a fuel electrode 11 and an oxidant electrode 12 in the thickness direction. Yes. Examples of the material of the solid polymer film 10 include a fluorocarbon resin (for example, perfluorosulfonic acid resin) or a hydrocarbon resin. The fuel cell 1 may be a system in which a plurality of sheet-like membrane electrode assemblies 13 are stacked in the thickness direction, or a system in which a plurality of tube-shaped membrane electrode assemblies 13 are arranged.

  As shown in FIG. 8, the reformer 2 includes a combustion section 30 formed of a combustion burner, a reforming section 34 heated by the combustion section 30, a combustion passage 32 facing the combustion section 30, and a combustion passage. 32, a combustion passage 33 communicating with the combustion passage 33, a combustion passage 35 communicating with the combustion passage 33, an evaporation section 36 for evaporating the raw material water, and a CO oxidation removal section 37 (also referred to as a CO selective oxidation section).

  The reforming portion 34 is disposed between the combustion passage 32 and the combustion passage 33, and has an inner passage 34i, an outer passage 34p, and a turn-up portion 34m. A cylindrical combustion passage 33 is arranged so as to surround the reforming section 34. The combustion passage 35 is a cylindrical passage that is folded back from the combustion passage 33. A cylindrical heat insulating portion 31 is disposed between the combustion passages 33 and 35. A cylindrical evaporator 36 is coaxially arranged so as to surround the combustion passage 35. The combustion passage 35 is coaxially disposed on the inner peripheral side of the evaporation portion 36. The evaporator 36 is heated by the combustion gas that passes through the combustion passage 35. A normal CO oxidation removing unit 37 is arranged so as to surround the evaporation unit 36. Therefore, the evaporation unit 36 and the CO oxidation removal unit 37 are mutually heat-exchanged.

  On the outer periphery of the CO oxidation removing portion 37, a heat insulating cylindrical heat insulating layer 39 is disposed.

  The reforming unit 34 includes a carrier that supports a reforming catalyst 34e that promotes a reforming reaction. The active temperature range of the reforming catalyst 34e is generally 500 to 800 ° C., but is not limited thereto. The reforming unit 34 performs steam reforming based on the reforming fuel and steam based on the following formula (1) to generate reformed gas containing hydrogen as a main component. The reformed gas contains carbon monoxide.

  Further, as shown in FIG. 8, the reformer 2 includes a heat exchanging unit 4 disposed below the reforming unit 34 and a CO shift unit 5 (hazardous component purification unit) disposed below the heat exchanging unit 4. ) And a warm-up unit 47 (heater) disposed between the CO shift unit 5 and the heat exchange unit 4. Here, the heat exchange unit 4 is provided downstream of the evaporation unit 36, and the CO shift unit 5 is provided downstream of the heat exchange unit 4.

  Based on the following formula (2), the CO shift unit 5 promotes a shift reaction for reducing oxygen monoxide using water vapor, and reduces CO contained in the reformed gas. The CO shift unit 5 includes a carrier that supports a shift catalyst 5e (for example, a copper-zinc catalyst). The active temperature range of the shift catalyst 5e is generally 200 to 300 ° C., but is not limited thereto. If the temperature of the CO shift unit 5 greatly deviates from the activation temperature range, the shift reaction of the CO shift unit 5 may be impaired, and carbon monoxide may not be sufficiently purified. The concentration of CO contained in the reformed gas purified by the CO shift unit 5 is generally 0.2 to 1% in molar ratio, although it depends on the reforming fuel. However, it is not limited to this. The CO shift unit 5 has a passage 5i, a passage 5v, and a turning portion 5m. The outlet 5p of the CO shift unit 5 and the oxidation air passage 75 are connected by a purification passage 400 via the second merge region M2.

The CO oxidation removing unit 37 (hazardous component purifying unit) is disposed downstream of the CO shift unit 5, and CO contained in the reformed gas that has passed through the CO shift unit 5 is converted into carbon dioxide as the following formula (3 ) To promote an oxidation reaction that is reduced by oxidation. The CO oxidation removing unit 37 includes a carrier that supports a selective oxidation catalyst 37e (for example, ruthenium-based). The active temperature range of the selective oxidation catalyst 37e is generally 100 to 200 ° C. However, it is not limited to this. If the temperature of the CO oxidation removing unit 37 is greatly deviated from the activation temperature range, the oxidation reaction in the CO oxidation removing unit 37 may be impaired. The concentration of CO contained in the reformed gas purified by the CO oxidation removing unit 37 is generally 10 ppm or less. However, it is not limited to this.
Formula (1) ... CH ₄ + H ₂ O → 3H ₂ + CO (endothermic reaction)
Formula (2): CO + H ₂ O → H ₂ + CO ₂ (exothermic reaction)
Formula (3): CO + 1 / 2O ₂ → CO ₂ (exothermic reaction)
According to the present embodiment, since the CO shift unit 5 is arranged upstream of the CO oxidation removal unit 37, it is executed in the order of Expression (2) → Expression (3).

  Next, the passage system will be described. As shown in FIG. 8, a fuel passage 62 is provided. The fuel of the combustion supply source 61 flowing through the fuel passage 62 may be gaseous fuel, liquid fuel, or pulverized fuel. Specific examples include hydrocarbon fuels such as city gas, LPG, kerosene, methanol, dimethyl ether, biogas, and alcohol fuels (such as methanol and ethanol). The fuel passage 62 is connected to the combustion fuel passage 62x connected to the combustion section 30 of the reforming section 34 via the valve 25a and the pump 37a, and to reforming connected to the inlet 4i of the heat exchange section 4 via the pump 37b and the valve 25b. And a fuel passage 62y (reforming fuel supply unit). An air passage 72 (oxygen supply unit) connected to the air supply source 71 is provided. The air passage 72 is connected to the combustion air passage 73 connected to the combustion portion 30 of the reforming portion 34 via the pump 37c, and the oxidation air passage 75 connected to the inlet 37i of the CO oxidation removal portion 37 via the pump 37d and the valve 25d. And have.

  As shown in FIG. 8, a reforming water passage 82 is provided that connects the water tank 81 and the inlet 36i of the evaporator 36 via a pump 27m and a valve 25m. An anode gas passage 100 that connects the outlet 37p of the CO oxidation removing unit 37 and the inlet 11i of the fuel electrode 11 of the fuel cell 1 via a valve 25e is provided. An off-gas passage 110 is provided that connects the outlet 11p of the fuel electrode 11 of the fuel cell 1 and the combustion unit 30 via a valve 25f. The off gas passage 110 discharges the anode off gas after the power generation reaction. A bypass passage 150 that connects the off gas passage 110 and the anode gas passage 100 via the valve 25h is provided.

  As shown in FIG. 8, a cathode gas passage 200 communicating with the air supply source 71 and the inlet 12i of the oxidant electrode 12 of the fuel cell 1 via a pump 37k and a valve 25k is provided. A combustion exhaust gas passage 250 for releasing the combustion exhaust gas combusted in the reforming unit 34 to the outside is provided. A water vapor passage 300 is provided that connects the outlet 36p of the evaporation section 36 and the reforming fuel passage 62 via the first merge region M1. The upper end portion 300e of the water vapor passage 300 is connected to the outlet 36p. The lower end portion 300f of the water vapor passage 300 is connected to the merge area M1.

  As shown in FIG. 8, the outlet 5 p of the CO shift unit 5 and the inlet 37 i of the CO oxidation removing unit 37 are connected by a purification passage 400. The reformed gas (containing hydrogen and carbon monoxide) discharged from the outlet 5p of the CO shift unit 5 flows upward in the direction of the arrow W2 through the purification passage 400, passes through the second merging zone M2, and flows through the CO oxidation removal unit 37. It is supplied to the inlet 37i.

  Next, the case where the reformer 2 is started will be described. In this case, combustion air is supplied to the combustion unit 30 via the combustion air passage 73 by the pump 37c. Further, the combustion fuel is supplied to the combustion unit 30 through the combustion fuel passage 62x by the valve 25a and the pump 37a. As a result, the combustion section 30 is ignited and heated, and as a result, the reforming section 34 is heated so as to be suitable for the reforming reaction. The evaporating unit 36 is also heated to a high temperature together with the reforming unit 34.

  Thereafter, the reforming water (liquid phase, raw material water) is supplied from the water tank 81 and the reforming water passage 82 to the inlet 36i of the evaporation section 36 via the pump 27m and the valve 25m. The reformed water is steamed in the evaporation unit 36. The generated water vapor reaches the first merge region M1 through the water vapor passage 300 from the outlet 36p of the evaporation section 36. The first merge region M1 is a region where the steam or condensed water flowing through the steam passage 300 and the reforming fuel flowing through the reforming fuel passage 62y merge. On the other hand, the reforming fuel is supplied to the inlet 4i of the heat exchanging section 4 through the reforming fuel passage 62y and the first junction region M1 by the valve 25a, the pump 37b, and the valve 25b. In the first merge region M1, the reforming fuel in the reforming fuel passage 62y and the water (liquid phase + gas phase) in the steam passage 300 are merged and mixed. The merged mixed fluid is supplied to the inlet 4 i of the heat exchange unit 4. The mixed fluid passes through the first passage 4 a on the low temperature side of the heat exchange unit 4. At this time, heat exchange is performed with the high-temperature reformed gas flowing through the second passage 4c on the high temperature side of the heat exchange unit 4. For this reason, the mixed fluid before the reforming reaction is heated. The mixed fluid flows into the outer passage 34p of the reforming portion 34, flows in the direction of arrow A1, flows into the inner passage 34i through the turn-up portion 34m, and flows in the direction of arrow A2. At this time, the mixed fluid in which the steam (or condensed water) and the reforming fuel are mixed becomes a hydrogen-rich reformed gas by the reforming reaction shown in (1). This reformed gas contains carbon monoxide.

  Further, the high-temperature reformed gas that has undergone the reforming reaction passes through the second passage 4c on the high temperature side of the heat exchanging section 4 from the reforming section 34, whereby the mixed fluid (liquid phase) in the first passage 4a on the low temperature side. + Gas phase) is heated. That is, heat exchange is performed. Further, the reformed gas cooled by the heat exchange unit 4 flows into the CO shift unit 5 from the inlet 5 i of the CO shift unit 5 through the warm-up unit 47. In the CO shift unit 5, a shift reaction using water vapor is performed as shown in the above formula (2). As a result, the carbon monoxide contained in the reformed gas is reduced and the reformed gas is purified.

Further, the reformed gas purified in the CO shift unit 5 flows from the outlet 5p of the CO shift unit 5 through the purification passage 400 in the direction of the arrow W2 and reaches the second merge region M2. Further, the reformed gas merges with the oxidizing air (oxygen component, selective oxidizing air used for the selective reaction in the CO oxidation removing unit 37) in the oxidizing air passage 75 (oxygen supply unit) in the second merge region M2. . The second merge region M2 is a region where the reformed gas flowing through the purification passage 400 and the oxidation air flowing through the oxidation air passage 75 merge. The merged reformed gas flows into the CO oxidation removing unit 37 from the inlet 37i. In the CO oxidation removing unit 37, an oxidation reaction (CO + 1 / 2O ₂ → CO ₂ ) using oxygen is performed as shown in the above formula (3). As a result, CO contained in the reformed gas is purified and further reduced. The oxidation reaction is exothermic.

  The reformed gas thus purified is supplied as an anode gas from the outlet 37p of the CO oxidation removing section 37 to the inlet 11i of the fuel electrode 11 of the fuel cell 1 through the anode gas passage 100 and the valve 25e. The air functioning as the cathode gas is supplied to the inlet 12i of the oxidant electrode 12 of the fuel cell 1 through the cathode gas passage 200 by the pump 37k and the valve 25k. As a result, a power generation reaction occurs in the fuel cell 1 and electric energy is generated. The off-gas after the power generation reaction of the anode gas may include hydrogen that has not undergone the power generation reaction. For this reason, the off gas is supplied to the combustion unit 30 of the reforming unit 34 through the off gas passage 110 and burned, and becomes a heat source of the combustion unit 30.

  In addition, at the time of starting the reforming apparatus 2, the stability of the reformed gas composition may not always be sufficient. For this reason, the valve 25e and the valve 25f are closed at the start of activation. In this state, the reformed gas discharged from the CO oxidation removing unit 37 passes through the valve 25 h and is sent to the combustion unit 30 through the bypass passage 150 and the off-gas passage 110 and serves as a heat source for the combustion unit 30. As time elapses from the start of the reforming device 2, the composition of the reformed gas becomes stable. In this case, the valve 25h is closed and the valves 25e and 25h are opened. For this reason, the reformed gas discharged from the CO oxidation removing unit 37 is supplied as an anode gas to the inlet 11i of the fuel electrode 11 of the fuel cell 1 through the anode gas passage 100 and the valve 25e, and used for the power generation reaction. .

  As shown in FIG. 8, a temperature sensor 55 that detects a temperature T2 on the upstream side (inlet side of the passage 5i) of the CO shift unit 5 is provided. A temperature sensor 38 that detects the temperature T3 on the upstream side of the CO oxidation removing unit 37 is provided. Further, a reforming section temperature sensor 31t that detects a temperature T4 on the outlet side of the inner section 34 of the reforming section 34 is provided. A temperature sensor 65 is provided for detecting the temperature T1 of the first merge region M1 where the steam and the reforming fuel merge.

  Even in this embodiment, even when the operating conditions of the reformer 2 change due to load fluctuations or when disturbances occur in steady operation, harmful components of the reformed gas are removed. This is advantageous for stabilizing the temperature T2 of the CO shift section 5 to be reduced. If the temperature T2 of the CO shift unit 5 is stabilized, it is advantageous to stabilize the temperature T3 of the CO oxidation removing unit 37.

(Other)
The present invention is not limited to the above-described embodiments, and can be modified as appropriate without departing from the scope of the invention. The harmful component purification unit 5A includes a CO shift unit 5 that oxidizes carbon monoxide by a shift reaction between carbon monoxide and water vapor to change it to carbon dioxide, and a CO that reacts carbon monoxide with oxygen to change it to carbon dioxide. An oxidation removal unit 37 is provided. Not only this but the type which has only any one of the CO shift part 5 and the CO oxidation removal part 37 may be sufficient.

  In the embodiment shown in FIG. 8, the evaporation unit 36 and the CO oxidation removal unit 37 are integrated with the reforming unit 34, but not limited to this, may be separated from the reforming unit 34 in terms of distance, Further, the CO shift unit 5 may be separated from the reforming unit 34 in terms of distance. In the embodiment shown in FIG. 8, the heat exchange unit 4 and the CO shift unit 5 are provided below the reforming unit 34, but the heat exchange unit 4 and the CO shift unit 5 are provided above the reforming unit 34. May be.

  The present invention can be used for a reformer used in a fuel cell system or the like.

1 is a system diagram illustrating a basic configuration of a reformer according to Embodiment 1. FIG. The graph which shows the time change regarding Example 1, temperature T1, T2, and the flow volume of reforming water. 10 is a flowchart executed by a control unit according to the second embodiment. FIG. 6 is a system diagram illustrating a basic configuration of a reformer according to a fourth embodiment. FIG. 10 is a system diagram illustrating a basic configuration of a reformer according to a fifth embodiment. FIG. 10 is a system diagram illustrating a basic configuration of a reformer according to a sixth embodiment. FIG. 10 is a system diagram illustrating a basic configuration of a reformer according to a seventh embodiment. FIG. 10 is a system diagram illustrating a basic configuration of a reformer according to an eighth embodiment.

Explanation of symbols

  1 is a fuel cell, 2 is a reformer, 30 is a combustion section, 27m is a pump (raw water supply section), 300 is a steam passage (water passage), 34 is a reforming section, and 36 is an evaporation section (gas-liquid mixed fluid) Generating section), 37 is a CO oxidation removing section, 4 is a heat exchange section, 4a is a first passage, 4c is a second passage, 5A is a harmful component purification section, 5 is a CO shift section, 81 is a water tank, and 82 is a modified tank. A quality water passage (reformed water supply unit) 500 is a control unit, 55 is a temperature sensor, 65 is a temperature sensor (detection unit), and 330 is a heating element.

Claims (7)

A reforming section for generating reformed gas from a fuel raw material by a reforming reaction;
A harmful component purification unit for reducing harmful components of the reformed gas generated in the reforming unit;
Water having a first passage and a second passage that can exchange heat with each other, water flowing through the first passage, and the reformed gas that flows through the second passage and travels from the reforming section to the harmful component purification section. A heat exchange part that cools the reformed gas and supplies the harmful gas purification part by heat exchange;
A water supply unit for supplying water to the first passage of the heat exchange unit through a water passage;
A physical quantity relating to a state of water before flowing into the first passage of the heat exchange section is detected directly or indirectly, and according to the detected physical quantity, the cooling capacity of the first passage of the heat exchange section and And / or a control unit that controls the temperature of the harmful component purification unit.   In Claim 1, the said control part controls the cooling capacity of the said 1st channel | path, and / or the temperature of the said harmful | toxic component purification | cleaning part by controlling the state of the water before flowing into the said 1st channel | path of the said heat exchange part. The reformer characterized by controlling.   3. The reformer according to claim 1, wherein the control unit includes a detection unit that directly or indirectly detects a state of water before flowing into the first passage.   In one of Claims 1-3, the said control part calculates | requires a temperature fall differential value about the physical quantity regarding the state of the water before flowing in into the said 1st channel | path of the said heat exchange part, Based on the said temperature fall differential value The reformer is characterized by controlling the cooling capacity of the first passage of the heat exchange unit and / or the temperature of the harmful component purification unit. 5. The gas-liquid mixing according to claim 1, wherein the water supply unit heats the raw water to generate a gas-liquid mixed fluid containing liquid-phase water and gas-phase water and leads to the water passage. A fluid generation unit, and a raw water supply unit for supplying the raw water to the gas-liquid mixed fluid generation unit,
The water that is heated by heat exchange in the first passage of the heat exchange section and flows out of the first passage is supplied to the reforming section to perform the reforming reaction. .   The unit of raw water supplied to the gas-liquid mixed fluid generating unit when the cooling capacity of the first passage of the heat exchanging unit is excessive than a predetermined value according to claim 5. A reformer characterized by reducing the flow rate per hour.   In one of Claims 1-6, when the heating element is provided in the water passage, and the cooling capacity of the first passage of the heat exchanging portion is more than a predetermined value, the control portion is A reforming apparatus that performs an operation of operating the heating element or an operation of increasing a heat generation amount of the heating element.

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