JP2005158428A - Starting method and starting control device of evaporator in fuel cell system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress thermal shock generated at starting and restarting of an evaporator. <P>SOLUTION: This is a starting method of the evaporator 5 in a fuel cell system with a reformer 5. When the detected temperature by a temperature detecting means S at the time of starting of the evaporator 5 is a prescribed temperature or more which is set beforehand, the fluid in the fuel cell system 1, for example, air is supplied to the evaporator 5, and the temperature of the evaporator 5 is lowered to a prescribed temperature or less, and then a high temperature fluid and a low temperature fluid are supplied to the evaporator 5 by high temperature fluid supply means 4, 25 and low temperature fluid supply means 36, 37. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an evaporator activation method and activation control apparatus in a fuel cell system.

  As an application example of a heat exchanger that exchanges heat between a gas-phase high-temperature fluid and at least a liquid-phase low-temperature fluid at the time of supply, the raw material gas that has been supplied to the reforming reactor of the fuel cell system has been conventionally evaporated. The evaporator obtained by this is known (refer patent document 1).

This evaporator introduces combustion gas obtained by burning the anode exhaust gas of the fuel cell into a pipe disposed in the evaporation chamber as an evaporation heat source, and directs the liquid raw material from the raw material injection device provided in the upper part of the evaporation chamber toward the pipe. By being injected, it is configured to evaporate and gasify as a raw material gas.
Japanese Patent Laid-Open No. 2002-124278

  However, in the above-described conventional example, the liquid material is injected into a pipe into which an evaporation heat source in the evaporator is introduced to evaporate and gasify. Therefore, at the time of start-up, etc., due to the temperature difference between the liquid material and the evaporator Due to thermal shock, excessive thermal stress is generated in the evaporator itself, and the reliability of the evaporator is lowered.

  In addition, when using the above conventional example as an evaporator that injects and evaporates liquid raw material only during a transient response that additionally requires raw material gas, excessive heat is generated in the evaporator due to the temperature difference. There is a problem that stress is generated and the reliability of the evaporator is lowered.

  Therefore, the present invention has been made in view of the above problems, and provides an evaporator startup method and startup control apparatus for a fuel cell system that can suppress thermal shock that occurs when the evaporator is started and restarted. For the purpose.

  The present invention is an evaporator start-up control device for exchanging heat between a high-temperature fluid and a low-temperature fluid in order to supply water vapor to a fuel cell system equipped with a reformer, and a temperature detection means for detecting the temperature of the evaporator Means for supplying high temperature fluid to the evaporator, means for supplying low temperature fluid to the evaporator, means for supplying fluid in the fuel cell system to the evaporator, and temperature detected by the temperature detecting means when the evaporator is started Is equal to or higher than a predetermined temperature set in advance, the fluid in the fuel cell system is supplied to the evaporator by the fluid supply means in the fuel cell system, and the temperature of the evaporator is lowered to a predetermined temperature or lower. And an activation control means for supplying the high temperature fluid and the low temperature fluid to the evaporator by the high temperature fluid supply means and the low temperature fluid supply means.

  Therefore, in the present invention, when the temperature detected by the temperature detecting means is equal to or higher than a predetermined temperature when the evaporator is started by the start control means, the fluid supply means in the fuel cell system causes the Since the fluid is supplied to the evaporator, the temperature of the evaporator is lowered below a predetermined temperature, and then the high temperature fluid supply means and the low temperature fluid supply means are used to supply the high temperature fluid and the low temperature fluid to the evaporator. In addition, it is possible to prevent the occurrence of excessive thermal stress due to thermal shock in the evaporator and improve the durability reliability of the evaporator.

  Hereinafter, a starting method and a starting control device for an evaporator in a fuel cell system of the present invention will be described based on each embodiment.

(First embodiment)
1 to 6 show a first embodiment of an evaporator activation control device in a fuel cell system to which the present invention is applied. FIG. 1 is a system configuration diagram of a fuel cell system for a moving body, and FIG. 2 is an evaporator. 3 is a perspective view of the heat exchange surface of FIG. 3, FIG. 3 is a start control flow chart of the start control device of the evaporator, FIG. 4 is a time chart showing a temporal change in the supply fluid supply flow rate and the evaporator temperature at the start of the evaporator 5 is a schematic view showing another example of the fluid passage of the evaporator, and FIG. 6 is a schematic view showing still another example of the fluid passage of the evaporator.

  In FIG. 1, a fuel cell system 1 includes a reformer 2 that generates a hydrogen-rich reformed gas from a raw material gas, and a fuel cell stack 3 that generates power using hydrogen contained in the reformed gas and oxygen contained in the air. A combustor 4 that combusts the anode exhaust gas of the fuel cell stack 3 with air, a transient response evaporator 5 that generates steam to be supplied to the reformer 2 by the heat of the combustion gas introduced from the combustor 4, A heat exchanger 6 that cools the combustion gas from the evaporator 5 or the exhaust hydrogen combustor 4, and a capacitor 7 that separates and recovers the water contained in the exhaust gas joined from the combustion gas and the fuel cell stack 3. Prepare. The system 1 further includes a raw material supply means 8 for supplying a raw material gas, an air supply means 9 for supplying air, and a water supply means 10 for supplying water. In addition, the fuel cell system 1 is controlled. The controller 11 is provided.

  The reformer 2 heats the steam supplied to the reforming reactor 14 by the reforming reactor 14 that reforms the supplied fuel with steam mixed with air and water, and the reformed gas from the reforming reactor 14. Heat exchanger 15, a shift reactor 16 for obtaining hydrogen by reacting carbon monoxide in the reformed gas with water, and carbon monoxide selective oxidation for reducing the carbon monoxide in the reformed gas to a predetermined concentration A reactor 17 and an evaporator 18 for evaporating water by heat generated in the carbon monoxide selective oxidation reactor 17 and sensible heat of the reformed gas are provided.

  The reforming reactor 14 is composed of a hydrocarbon-based fuel introduced by a pump 22 from a fuel tank 21 of the raw material supply means 8, a hydrogen-rich material in which hydrogen is about 30% from raw materials of steam and air passing through the evaporator 15. To a new reformed gas. The water vapor and air evaporate water supplied from the water supply system 10 by an evaporator 18 that evaporates water by heat generated in the carbon monoxide selective oxidation reactor 17 and sensible heat of the reformed gas, and further air supply means. 9 is supplied in a heated state from a normal supply system that passes through the heat exchanger 15 together with air from 9. Further, when the required water vapor is insufficient, the transient response evaporator 5 also evaporates the water supplied from the water supply system 10 to generate water vapor to generate the water vapor via the path 24 and also from the transient response supply system. Steam is supplied.

  The reforming reactor 14 is supplied with a hydrocarbon-based fuel and steam and air heated by the heat exchanger 15 as reforming raw materials, and these raw materials are hydrogen-rich reformed gas containing CO. And is supplied to the heat exchanger 15. This reformed gas is converted to a reformed gas having about 30% hydrogen.

  The heat exchanger 15 is configured to supply sensible heat of the reformed gas to the passing steam and air by heat exchange, and functions to sufficiently heat the steam and air supplied to the reforming reactor 14.

  The shift reactor 16 adds water supplied from the water supply means 10 to the reformed gas after passing through the heat exchanger 15, and reduces CO in the reformed gas by a reaction in the built-in aqueous shift catalyst layer. And fed to the selective oxidation reactor 17. The CO in the reformed gas is converted into hydrogen and inert CO2 by reacting with water supplied separately. Here, hydrogen becomes a reformed gas of about 35%.

  The selective oxidation reactor 17 receives a supply of reformed gas to which air has been added after passing through the shift reactor 16, and further reduces CO in the reformed gas by a reaction in a built-in CO selective oxidation catalyst layer. The reformed gas with reduced CO is supplied to the fuel cell stack 3. The selective oxidation reactor 17 is provided with an evaporator 18, and the water supplied from the water supply means 10 is subjected to sensible heat of the reformed gas and heat of oxidation reaction to produce water vapor. Supply to the exchanger 15. The steam is further heated by the sensible heat of the reformed gas in the heat exchanger 15 and introduced into the reforming reactor 14 as a reforming raw material.

  The fuel cell stack 3 generates electricity by an electrochemical reaction between hydrogen contained in the reformed gas from the reformer 2 and oxygen contained in the air supplied from the air supply means 9. The anode exhaust gas discharged without being subjected to the electrochemical reaction is supplied to the exhaust hydrogen combustor 4, and the cathode exhaust gas is combined with the exhaust combustion gas from the exhaust hydrogen combustor 4 and supplied to the capacitor 7.

  The exhaust hydrogen combustor 4 burns the anode exhaust gas from the fuel cell stack 3 with the air sent from the air supply system 9 and supplies the combustion gas to the three-way valve 25. The three-way valve 25 switches whether the supplied combustion gas is supplied to the heat exchanger 6 via the evaporator 5 or supplied to the heat exchanger 6 via the bypass path 26 that bypasses the evaporator 5. It is configured as possible. Although the heat exchanger 6 depends on how the evaporator 5 is used, if necessary, the heat of the combustion exhaust gas is absorbed to adjust the temperature of the exhaust combustion gas, and the exhaust gas on the oxidizing gas side of the fuel cell stack 3 Combined and supplied to the capacitor 7. The condenser 7 cools the combined gas, condenses and collects water vapor contained in water, and then exhausts it to the outside air. The recovered water is returned to the water tank 31 and reused as reforming water.

  When the steam required by the reforming reactor 14 is insufficient, the evaporator 5 evaporates the water supplied from the water supply means 10 by the heat of the heated gas from the exhaust hydrogen combustor 4 to steam. Is an evaporator that supplies water vapor from a supply system during a transient response that passes through a path 24. That is, evaporation that generates vapor in the vapor phase from water by heat exchange between the high-temperature fluid of the heated gas from the exhaust hydrogen combustor 4 and the low-temperature fluid of the liquid phase water supplied from the water supply means 10. It is comprised by the heat exchanger which functions as an oven. The water supply means 10 includes a valve 27 that is opened when the evaporator is in operation, and supplies water to the evaporator 5 via the valve 27.

  As shown in the partial perspective view of the heat exchange surface in FIG. 2, the evaporator 5 circulates the air supplied from the air supply means 9 in addition to the high temperature fluid passage 40 and the low temperature fluid passage 41. A passage 42 is provided adjacent to both the hot fluid passage 40 and the cold fluid passage 41. That is, a layer in which water and evaporated water vapor flow and a layer in which exhaust gas and air flow are alternately stacked between the plurality of plates 43 constituting the heat exchange surface. The flow path 40 through which the exhaust gas flows and the flow path 42 through which the air flows are partitioned by the corrugated plate 44 or the like. The flow path cross-sectional area of the air flow path 42 and the flow path cross-sectional area of the exhaust gas flow path 40 may be set, for example, according to the shape of the corrugated plate 44 as shown in FIG. It can also be enlarged. The air whose temperature has risen via the evaporator 5 is supplied to the heat exchanger 15 of the reformer 2 through the path 28.

  As described above, when the exhaust gas flow path 40, the air flow path 42, and the water flow path 41 of the evaporator 5 are provided independently, it is only necessary that heat exchange is possible between the flow paths. For example, as shown in FIG. 5, the air flow path 42 may flow around the evaporator 5.

  As shown in the evaporator 5, the air flow path 42 is not newly provided independently of the exhaust gas flow path 40 and the water flow path 41, and the high temperature fluid path 40 or the low temperature fluid path 41 of the evaporator 5 is provided. The evaporator 5 may be cooled by circulating the air supplied from the air supply means 9.

  In this case, as shown in FIG. 6, the path 36 from the air supply means 9 is connected to the exhaust gas path downstream of the three-way valve 25, and the air that has passed through the evaporator 5 is transferred to the heat exchanger 15 of the reformer 2. Therefore, a normally-open shut-off valve 29 is inserted into the exhaust gas passage downstream of the evaporator 5 and branched from the shut-off valve 29 upstream to form a path 28, and a normally-closed shut-off valve 30 is provided in this path 28. Arrange and configure. When the evaporator 5 is cooled by air from the air supply means 9, the shutoff valve 29 downstream of the evaporator 5 is closed, and the shutoff valve 30 in the path 28 is opened, so that the supplied air is passed through the high-temperature fluid passage. The exhaust air can be supplied to the heat exchanger 15 of the reformer 2 through the shut-off valve 30 opened in the path 28. Although not shown, when the evaporator 5 is cooled by introducing air from the air supply means 9 into the water passage 41, the same passage switching means can be used.

  The water supply means 10 includes a system for supplying water stored in the water tank 31 to the evaporator 18 of the reformer 2 by a pump 32, and a system for supplying the water stored in the water tank 31 to the shift reactor 16 of the reformer 2 by a pump 33. And the supply system to the shift reactor 16 is branched, and after passing through the valve 27, can be supplied to the evaporator 5 for transient response.

  The air supply means 9 adjusts the flow rate of the compressed air from the blower 34 through the flow rate adjustment valve 35, then supplies the compressed air to the fuel cell stack 3 as an oxidant gas, and passes through the shift reactor 16 to perform the selective oxidation reaction. The reformed gas flowing into the reactor 17 is joined and supplied, supplied to the exhaust hydrogen combustor 4, and supplied to the heat exchanger 15 of the reformer 2 together with the steam from the evaporator 18. Further, the compressed air from the blower 34 is adjusted in flow rate by a flow rate adjusting valve 37 in a path 36 branched from the upstream side of the flow rate adjusting valve 35 and is supplied to the transient response evaporator 5. In addition, the code | symbol 38 in a figure is a confluence | merging valve which prevents the backflow of the fluid arrange | positioned at the confluence | merging part, respectively.

  The controller 11 includes these components of the fuel cell system 1, that is, the reformer 2, the fuel cell stack 3, the exhaust hydrogen combustor 4, the three-way valve 25, the transient response evaporator 5, the heat exchanger 6, and the condenser. 7 is configured to monitor the operation state and control its operation. Further, the pumps 22, 32, 33 and the blower 34 and the valves 25, 27, 35, 37 of the fuel supply means 8, the water supply means 10, and the air supply means 9 are controlled to be opened and closed.

  The operation of the fuel cell system 1 having the above configuration will be described below.

  During normal operation of the fuel cell system 1, the raw material supply means 8 and the pumps 22, 32 to 33 of the water supply means 10 and the blower 34 of the air supply means 9 are operated.

  The flow rate adjustment valve 37 of the air supply means 9 is closed and the flow rate adjustment valve 35 is opened to adjust the flow rate, and the upstream side of the carbon monoxide selective oxidation reactor 17 on the reformer 2, the heat exchanger 15, and the fuel cell. This is supplied to the stack 3 and the exhaust hydrogen combustor 4.

  The valve 27 disposed in the flow path to the evaporator 5 of the water supply means 10 is closed, and water is supplied only to the evaporator 18 and the shift reactor 16 attached to the carbon monoxide selective oxidation reactor 17 of the reformer 2. Supply.

  The reformer 2 is supplied with raw material gas, water, and air, and the evaporator 18 evaporates water by the heat generated in the carbon monoxide selective oxidation reactor 17 and the sensible heat of the reformed gas. At the same time, it is heated by the heat exchanger 15 and supplied to the reforming reactor 14.

  The reformed gas reformed in the reforming reactor 14 is heated by heating the heat exchanger 15 with the sensible heat of the reformed gas, and the shift reactor 16 reacts carbon monoxide and water in the reformed gas to reform. The hydrogen concentration in the gas is increased, and the carbon monoxide selective oxidation reactor 17 reduces the carbon monoxide in the reformed gas to a predetermined concentration, which is then supplied to the fuel cell stack 3.

  The fuel cell stack 3 generates electricity by an electrochemical reaction between hydrogen in the supplied reformed gas and oxygen in the air as an oxidant gas from the air supply means 9, and discharges exhaust hydrogen to the exhaust hydrogen combustor 4. On the other hand, the exhaust air is discharged to the capacitor 7.

  The exhaust hydrogen combustor 4 combusts the anode exhaust gas from the fuel cell stack 3 with the air sent from the air supply system 9 and supplies the combustion gas to the three-way valve 25. Since the three-way valve 25 is normally open to the bypass passage 26 side, the combustion gas is sent to the heat exchanger 6 via the bypass passage 26, and the heat of the combustion exhaust gas is absorbed by the heat exchanger 6 and discharged. The temperature of the combustion gas is adjusted, merged with the exhausted air, and sent to the condenser 7. The condenser 7 cools the merged gas, condenses the water vapor contained therein, recovers it, and then exhausts it to the outside air. .

  The transient response evaporator 5 is not supplied with any combustion gas from the exhaust hydrogen combustor 4, water from the water supply means 10, or air from the air supply means 9, and generates water vapor. Not in standby state.

  During the normal operation of the fuel cell system 1, when the steam required by the reforming reactor 14 is insufficient, the controller 11 executes the control flowchart shown in FIG. 3 and starts the transient response evaporator 5. Or restarted. Hereinafter, the starting or restarting of the evaporator 5 from the standby state will be described based on the flowchart of FIG. 3 and the time chart of FIG. 4.

  For starting or restarting the evaporator 5, a transient load input request is made from an external operation control system (not shown), for example, and the operation state of the fuel cell system 1 corresponds to the transient operation state. It is executed when the power generation output is increased as much as possible. That is, the controller 11 is activated or restarted when there is a transient load input request or the like by an external signal.

  In step S1, it is first determined whether or not the temperature detected by the temperature sensor S of the evaporator 5 is equal to or higher than a predetermined temperature. The predetermined temperature is set in advance by the temperature of the evaporator 5 at which a thermal shock is generated in the evaporator 5 when water which is a low-temperature fluid is introduced. When the evaporator 5 evaporates the introduced water by the transient response evaporator 5 as necessary, the evaporator 5 itself may be in a very high temperature state. Damage may occur due to thermal shock due to a temperature difference between water and the evaporator 5. If it is determined in step S1 that the temperature of the evaporator 5 is not equal to or higher than the predetermined temperature, the process proceeds to step S5. If the temperature of the evaporator 5 is equal to or higher than the predetermined temperature, the process proceeds to step S2. The time chart of FIG. 4 shows a case where the temperature of the evaporator 5 is equal to or higher than a predetermined temperature (see time t0).

  In step S2, the air of the air supply means 9 as the fluid in the fuel cell system 1 opens the flow rate control valve 37 and flows into the evaporator 5 while controlling the flow rate (see time point t1 in FIG. 4), and proceeds to step S3. . The air introduced into the evaporator 5 cools the evaporator 5 by flowing through the air flow path 42 of the evaporator 5, and the exhaust air whose temperature has risen due to heat exchange with the evaporator 5 passes through the path 28. It flows into the heat exchanger 15 of the reformer 2 together with the steam. Since the exhaust air that has flowed through the evaporator 5 in this way receives heat from the evaporator 5 and the heat exchange amount in the heat exchanger 15 may be small, the heat energy in the system 1 can be used effectively. . Due to the inflow of air, the temperature of the evaporator 5 is gradually lowered as shown in FIG.

  In step S3, it is determined whether or not the temperature of the evaporator 5 has decreased to a predetermined temperature or lower. If the temperature has decreased to a predetermined temperature or lower, the process proceeds to step S4. Returning to S2, the supply of air from the air supply means 9 to the evaporator 5 is continued. If the temperature of the evaporator 5 has dropped below the predetermined temperature due to the supply of air, the process proceeds to step S4, the flow rate adjustment valve 37 is closed (see time t2 in FIG. 4), and the process proceeds to step S5.

  In step S5, the valve 27 of the water supply means 10 is opened for a predetermined time set in advance to supply a predetermined amount of water to the water and water vapor passage 41 of the evaporator 5 (time t2 in FIG. 4), and the process proceeds to step S6. . When the water is supplied to the water passage 41, the evaporator 5 supplies its own sensible heat to the water to lower the temperature (see time points t2 to t3).

  In step S6, the three-way valve 25 is switched, the combustion gas of the exhaust hydrogen combustor 4 is introduced into the evaporator 5, and the process proceeds to step S7. Due to the inflow of combustion gas, which is a high-temperature fluid (see time t3), the evaporator 5 starts to rise in temperature and raises the temperature of the water passage 41 by sensible heat of the combustion gas (see time t3 to t4).

  In step S7, it is determined whether or not the temperature of the evaporator 5 exceeds the evaporation temperature of water. When the temperature exceeds the evaporation temperature, the process proceeds to step S8. When the temperature of the evaporator 5 exceeds the evaporation temperature (see time t4), the process proceeds to step S8, the valve 27 is opened, and water from the water supply means 10 as a low-temperature fluid is again introduced into the evaporator 5 and evaporated. The start-up and restart processing of the device 5 is terminated. The temperature of the evaporator 5 slightly decreases when it is supplied again from the water supply means 10, but the temperature starts to rise again, and the vaporized water vapor is converted into the reforming reactor 14 of the reformer 2 via the path 24. Additional supply.

  As described above, when the water introduced from the water supply means 10 is evaporated by the transient response evaporator 5 as necessary, the evaporator 5 itself may be in a very high temperature state. When the water flows in, the evaporator 5 may be damaged due to a thermal shock due to a temperature difference between the water and the evaporator 5. In such a case, by introducing relatively low temperature air from the air supply means 9 into the evaporator 5, the evaporator 5 is first lowered to a predetermined temperature or less and then water to be evaporated is supplied to the evaporator 5. Therefore, in the evaporator 5 that is started or restarted as necessary or in accordance with the transient response situation, the temperature is not more than a predetermined temperature that does not cause a thermal shock in the transient response evaporator 5 in advance. Can be prevented, and can be prevented from being damaged due to thermal shock, and durability reliability can be improved.

  Furthermore, since the air that has cooled the evaporator 5 receives heat from the evaporator 5 and has a temperature rise, the amount of heat exchange from the reformed gas may be small when passing through the heat exchanger 15 of the reformer 2. The heat energy in the fuel cell system 1 can be used effectively.

  In the present embodiment, the following effects can be achieved.

  (A) When the temperature detected by the temperature detecting means S is equal to or higher than a predetermined temperature when the evaporator 5 is started by the controller as the start control means, the fluid in the fuel cell system 1 is transferred to the evaporator 5 Then, the temperature of the evaporator 5 is lowered to a predetermined temperature or lower, and then the high temperature fluid supply means (4, 25) and the low temperature fluid supply means (33, 27) are supplied to the evaporator 5 with the high temperature fluid and the low temperature fluid. Since it supplies, the generation | occurrence | production of the excessive thermal stress by the thermal shock to the evaporator 5 can be prevented, and the durable reliability of the evaporator 5 can be improved.

  (A) When the temperature detected by the temperature detecting means S is equal to or higher than a predetermined temperature when the evaporator 5 is activated, air introduced from the air supply means 9 is distributed as a fluid in the fuel cell system 1 Since the exhaust air supplied to the evaporator 5 and discharged through the evaporator 5 is supplied to the reforming reactor 14 via the heat exchanger 15 of the reformer 2, the transient response evaporator 5 is supplied. Therefore, at the same time, it is possible to prevent the thermal shock from being generated in the evaporator 5 at the time of re-response, and at the same time, the air warmed in the evaporator 5 flows into the reforming reactor 14. Can be used effectively.

  (C) Since the fuel cell system 1 is mounted on an electric vehicle, the thermal shock of the transient response evaporator 5 that requires steam supply according to various operating conditions is prevented, and durability reliability is improved. Can be improved.

(Second Embodiment)
FIG. 7 is a system configuration diagram showing a second embodiment of an evaporator activation control device in a mobile fuel cell system to which the present invention is applied. In the first embodiment, when the temperature of the transient response evaporator is equal to or higher than the predetermined temperature, air from the air supply means is introduced to cool the evaporator, but in this embodiment, humidification is performed. Water vapor generated in the evaporator of the evaporator is introduced into the evaporator for transient response to cool the evaporator. The same devices as those in FIGS. 1 to 6 are denoted by the same reference numerals, and description thereof is omitted or simplified.

  7, in the fuel cell system 1 of the present embodiment, the branch passage 36 and the valve 37 of the air supply means 9 of the first embodiment shown in FIG. 1 are omitted, and the steam of the evaporator 18 of the reformer 2 is heated. A normally open flow rate adjustment valve 51 is inserted in the middle of the passage 50 supplied to the exchanger 15, and a water vapor introduction passage 52 that branches from the upstream side of the flow rate adjustment valve 51 and communicates with the transient response evaporator 5 is provided. A normally closed flow rate adjustment valve 53 is arranged in the middle of the water vapor introduction passage 52. As shown in FIG. 5, the steam introduced into the evaporator 5 passes through the periphery of the transient response evaporator 5 and is discharged, and is supplied to the heat exchanger 15 of the reformer 2 through the path 28. It is configured as follows.

  When the evaporator 5 for transient response is started or restarted, the control flowchart for starting or restarting the evaporator for transient response shown in FIG. 3 of the first embodiment is executed. The fluid in the system that is introduced into the evaporator 5 in steps S3 to S5 of this control flowchart is water vapor that distributes and introduces part of the water vapor supplied to the heat exchanger 15 by opening the flow control valve 53. . The remaining water vapor is supplied to the heat exchanger 15. The introduced water vapor passes around the evaporator 5 and is heated by sensible heat from the evaporator 5, and the evaporator 5 is cooled by heating the water vapor. For this reason, the temperature of the evaporator 5 for transient response can be lowered in advance to a predetermined temperature at which the thermal shock of the transient response evaporator 5 does not occur, and the thermal shock of the evaporator 5 can be prevented as necessary. And the durability reliability can be improved.

  Since the water vapor that has passed through the evaporator 5 is heated by sensible heat from the evaporator 5, the amount of heat exchange in the heat exchanger 15 of the reformer 2 may be small, and the heat energy in the fuel cell system 1 is effective. Can be used.

  In the present embodiment, in addition to the effects (a) to (c) in the first embodiment, the following effects can be achieved.

  (D) When the temperature detected by the temperature detecting means S is equal to or higher than a predetermined temperature set when the evaporator 5 is started, the fluid is supplied to the reforming reactor 14 of the reformer 2 as a fluid in the fuel cell system 1. Steam is distributed and supplied to the evaporator 5, and the steam discharged through the evaporator 5 is supplied to the reforming reactor 14 via the heat exchanger 15 of the reformer 2. By reducing the temperature of the evaporator 5 and preventing the occurrence of thermal shock in the evaporator 5 at the time of re-response, the air heated by the evaporator 5 is caused to flow into the reforming reactor 14, so that the fuel cell system The heat energy in 1 can be used effectively.

(Third embodiment)
FIG. 8 is a system configuration diagram showing a third embodiment of an activation control device for an evaporator in a fuel cell system for a moving body to which the present invention is applied. In the first embodiment, when the temperature of the transient response evaporator is equal to or higher than a predetermined temperature, air from the air supply means is introduced to cool the evaporator. The exhaust gas heat-exchanged and cooled by the exchanger 6 and the condenser 7 is introduced into the transient response evaporator 5 to cool the evaporator 5. 1 to 7 are denoted by the same reference numerals, and description thereof is omitted or simplified.

  8, the fuel cell system 1 of the present embodiment has a branch passage 36 and a valve 37 of the air supply means 9 of the first embodiment shown in FIG. A normally open flow rate adjusting valve 56 is inserted, and an exhaust introduction passage 57 that branches from the upstream side of the flow rate adjustment valve 56 and communicates with the transient response evaporator 5 is provided. A regulating valve 58 is arranged. As shown in FIG. 5, the exhaust gas introduced into the evaporator 5 passes through the periphery of the transient response evaporator 5 and is then discharged to the outside air.

  When the transient response evaporator 5 is started or restarted, the control flowchart for starting or restarting the transient response evaporator 5 shown in FIG. 3 of the first embodiment is executed. The fluid in the system that is introduced into the evaporator 5 in steps S3 to S5 of this control flowchart is exhaust that distributes and introduces part of the exhaust that has passed through the condenser 7 by opening the flow control valve 58. The remaining exhaust is discharged to the outside air via the flow control valve 56. The introduced exhaust gas is heated by sensible heat from the evaporator 5 by passing around the evaporator 5, and the evaporator 5 is cooled by heating the exhaust gas. For this reason, the temperature of the evaporator 5 can be lowered to a predetermined temperature or less so that the thermal shock of the transient response evaporator 5 does not occur in advance as necessary and at the time of re-response. The durability and reliability can be improved.

  In the present embodiment, in addition to the effects (a) to (c) in the first embodiment, the following effects can be achieved.

  (E) When the evaporator 5 is started, if the temperature detected by the temperature detection means S is equal to or higher than a predetermined temperature set in advance, the exhaust gas cooled and discharged from the fuel cell system 1 is used as the fluid in the fuel cell system 1 Since this is distributed and supplied to the evaporator 5, the temperature of the evaporator 5 for transient response can be lowered, the thermal shock of the evaporator 5 can be prevented at the time of re-response, and the durability reliability can be improved.

(Fourth embodiment)
FIG. 9 is a system configuration diagram showing a fourth embodiment of the start-up control device for the evaporator of the fuel cell system for a moving body to which the present invention is applied. In the first embodiment, when the temperature of the transient response evaporator 5 is equal to or higher than the predetermined temperature, the air from the air supply means 9 is introduced to cool the evaporator 5 in the first embodiment. The exhaust air discharged from the fuel cell stack 3 and supplied to the capacitor 7 is introduced into the evaporator 5 for transient response to cool the evaporator 5. 1 to 8 are denoted by the same reference numerals, and the description thereof is omitted or simplified.

  9, the fuel cell system 1 of the present embodiment is configured such that the branch passage 36 and the valve 37 of the air supply means 9 of the first embodiment shown in FIG. 1 are deleted, and the exhaust discharged from the fuel cell stack 3 to the capacitor 7 is eliminated. A normally open flow rate adjustment valve 61 is inserted in the middle of the air passage 60, and includes an exhaust air introduction passage 62 that branches from the upstream side of the flow rate adjustment valve 61 and communicates with the transient response evaporator 5. In the middle of 62, a normally closed flow rate adjusting valve 63 is arranged. As shown in FIG. 5, the exhaust air introduced into the evaporator 5 is configured to be supplied to the heat exchanger 15 after passing around the evaporator 5 for transient response.

  When the transient response evaporator 5 is started or restarted, the control flowchart for starting or restarting the transient response evaporator 5 shown in FIG. 3 of the first embodiment is executed. The fluid in the system that is introduced into the evaporator 5 in steps S3 to S5 of this control flowchart is exhaust air that distributes and introduces part of the exhaust air that is discharged from the fuel cell stack 3 by opening the flow control valve 63. It is. The remaining exhaust air is supplied to the capacitor 7 via the flow control valve 61. The introduced exhaust air passes around the evaporator 5 and is heated by sensible heat from the evaporator 5, and the evaporator 5 is cooled by heating the exhaust air. For this reason, the temperature of the evaporator 5 can be lowered to a predetermined temperature or less so that the thermal shock of the transient response evaporator 5 does not occur in advance as necessary and at the time of re-response. The durability and reliability can be improved.

  In the present embodiment, in addition to the effects (a) to (c) in the first embodiment, the following effects can be achieved.

  (F) When the evaporator 5 is started, if the temperature detected by the temperature detecting means S is equal to or higher than a predetermined temperature set in advance, the exhaust air discharged from the fuel cell stack 3 is distributed as a fluid in the fuel cell system 1. In order to supply to the evaporator 5, the temperature of the evaporator 5 for transient response is lowered to prevent thermal shock from being generated in the evaporator 5 at the time of re-response, and the durability reliability of the evaporator 5 is improved. Can do.

  In each of the above embodiments, the start-up control device for the transient response evaporator 5 has been described as the evaporator 5 for supplying water vapor to the fuel cell system 1, but although not shown, from the exhaust hydrogen combustor 4. When the combustion gas is a high-temperature fluid, it can also be applied to an evaporator start-up control device during normal use.

The system block diagram of the starting control apparatus of the evaporator in the fuel cell system which shows one Embodiment of this invention. The partial perspective view of the heat exchange surface of an evaporator similarly. The flowchart of starting control of the evaporator by a controller. The time chart which shows the time change of the supply fluid supply flow rate at the time of starting of an evaporator, and the temperature of an evaporator. Schematic which shows another example of the fluid channel | path of an evaporator. Schematic which shows another example of the fluid channel | path of an evaporator. The system block diagram of the starting control apparatus of the evaporator in the fuel cell system which shows 2nd Embodiment of this invention. The system block diagram of the starting control apparatus of the evaporator in the fuel cell system which shows 3rd Embodiment of this invention. The system block diagram of the starting control apparatus of the evaporator in the fuel cell system which shows 4th Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fuel cell system 2 Reformer 3 Fuel cell stack 4 Exhaust hydrogen combustor 5 Evaporator, transient response evaporator 6, 15 Heat exchanger 7 Capacitor 8 Raw material supply means 9 Air supply means 10 Water supply means 14 Reformation Reactor 16 Shift reactor 17 Carbon monoxide selective oxidation reactor 18 Evaporator 24, 28 Path 25 Three-way valve 26 Bypass path 27, 29, 30 Valve 34 Blower 35, 37, 51, 53, 56, 58, 61, 63 Flow adjustment valve

Claims (11)

An evaporator start-up method for exchanging heat between a high-temperature fluid and a low-temperature fluid to supply water vapor to a fuel cell system equipped with a reformer,
When the temperature of the evaporator is higher than a predetermined temperature set in advance at the time of startup, before supplying the high-temperature fluid and the low-temperature fluid, the fluid below the predetermined temperature in the fuel cell system is temporarily supplied to the evaporator. A method of starting an evaporator in a fuel cell system, wherein the temperature of the evaporator is lowered to a predetermined temperature or lower, and then a low temperature fluid and a high temperature fluid are supplied to generate water vapor.   The fluid below a predetermined temperature in the fuel cell system is air supplied to the fuel cell system, exhaust gas cooled and discharged from the fuel cell system, water vapor supplied to the reforming reactor of the reformer, or fuel cell The method for starting an evaporator in a fuel cell system according to claim 1, wherein the starting method is any one of exhaust air discharged from a stack.   When the fluid below the predetermined temperature in the fuel cell system is air supplied to the fuel cell system or water vapor supplied to the reforming reactor of the reformer, the reformer after passing through the evaporator The method for starting an evaporator in a fuel cell system according to claim 2, wherein the reforming reactor is supplied via a heat exchanger. An activation control device for an evaporator that performs heat exchange between a high-temperature fluid and a low-temperature fluid in order to supply water vapor to a fuel cell system including a reformer,
Temperature detecting means for detecting the temperature of the evaporator;
Means for supplying hot fluid to the evaporator;
Means for supplying a cryogenic fluid to the evaporator;
Means for supplying fluid in the fuel cell system to the evaporator;
When the temperature detected by the temperature detection means is equal to or higher than a predetermined temperature when the evaporator is started, the fluid in the fuel cell system is supplied to the evaporator by the fluid supply means in the fuel cell system, and the evaporator And a start control means for supplying the high temperature fluid and the low temperature fluid to the evaporator by the high temperature fluid supply means and the low temperature fluid supply means. Evaporator start-up control device.   The fluid supply means in the fuel cell system distributes the air introduced from the air supply means and supplies the air to the evaporator, and the exhaust air discharged through the evaporator passes through the heat exchanger of the reformer. 5. The start-up control device for an evaporator in a fuel cell system according to claim 4, wherein the start-up control device is supplied to the reforming reactor.   The fluid supply means in the fuel cell system distributes the steam supplied to the reforming reactor of the reformer, supplies the steam to the evaporator, and exchanges the steam discharged through the evaporator for heat exchange of the reformer. 5. The start-up control device for an evaporator in a fuel cell system according to claim 4, wherein the start-up control device is supplied to the reforming reactor via a reactor.   5. The start of the evaporator in the fuel cell system according to claim 4, wherein the fluid supply means in the fuel cell system distributes the exhaust gas cooled and discharged from the fuel cell system and supplies the exhaust gas to the evaporator. Control device.   5. The start control device for an evaporator in a fuel cell system according to claim 4, wherein the fluid supply means in the fuel cell system distributes exhaust air discharged from the fuel cell stack and supplies the exhaust air to the evaporator. .   The evaporation in the fuel cell system according to any one of claims 4 to 8, wherein the supplied fluid in the fuel cell system flows through a high-temperature fluid passage or a low-temperature fluid passage of an evaporator. Start-up control device.   5. The supplied fluid in the fuel cell system flows through a fluid passage provided in or around the evaporator independently of the low-temperature fluid passage and the high-temperature fluid passage of the evaporator. The start-up control apparatus of the evaporator in the fuel cell system as described in any one of Claim thru | or 8.   The start control device for an evaporator in a fuel cell system according to any one of claims 4 to 10, wherein the fuel cell system is mounted on an electric vehicle.

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