JP2008218353A - Fuel cell power generation system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive fuel cell power generation system by measuring temperature of plant exhaust with a thermometer, and operating in a water self-supporting state without detecting a water level. <P>SOLUTION: A condenser 3 condenses cathode exhaust from a cathode 1 or burner exhaust from a burner 2, and accumulates it in an accumulating tank 6 as condensed water. An exhaust-gas thermometer 4 is fitted at an exhaust outlet 3a of the condenser 3, and measures temperature of plant exhaust. In case the temperature of the plant exhaust measured by the exhaust-gas thermometer 4 is higher than the temperature necessary for keeping a water self-supporting state, a control part 7 controls to increase the number of rotation of an exhaust heat recovery pump 5 to increase an amount of condensed water condensed by the condenser 3. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a fuel cell power generation system that includes a condenser and covers reformed water with condensed water. In particular, the amount of condensed water is adjusted by measuring the temperature of exhaust gas containing moisture such as cathode exhaust or burner exhaust. The present invention relates to a possible fuel cell power generation system.

  In recent years, fuel cells have attracted attention as energy conversion devices with high power generation efficiency. The fuel cell power generation system equipped with this fuel cell converts the combined energy of hydrogen and oxygen generated by the fuel processing device directly into electrical energy in the fuel cell body, and emits less pollutants and reduces noise. It is a power generation device with excellent environmental properties.

  In addition, the fuel processing apparatus which produces | generates the hydrogen supplied to a fuel cell main body is comprised from a reformer etc., and water is required for the reforming reaction inside the said reformer. Since the reformed water required for the reforming requires a certain level of purity, for example, when tap water is supplied from the outside and used as the reformed water, the tap water is treated with a water treatment resin or the like. Must be purified to reformed water of a predetermined purity.

  However, the operation of refining tap water with this water treatment resin or the like to reformed water of a predetermined purity requires work time and a certain amount of cost. Therefore, in a general fuel cell system, by a condenser, In some cases, the exhaust gas containing moisture such as cathode exhaust or burner exhaust is cooled and condensed by condensing the contained water and accumulating high-purity water. As a result, the condensed water accumulated has a high purity, so that water treatment is unnecessary or the water treatment load can be significantly reduced as compared with the case where tap water is used.

  In the polymer electrolyte fuel cell system, humidification is required to maintain the performance of the polymer electrolyte membrane, and water is usually required. For this reason, water is contained in the cathode exhaust due to humidification on the cathode side, and water is generated as a product of the electrochemical reaction. Therefore, water is recovered from the cathode exhaust and reused for supplying water to the reformer. It is hoped to do.

  Also, the burner uses hydrogen, which is the fuel remaining in the fuel cell, as fuel to burn the air supplied to the anode exhaust and the cathode side to heat the reformer and so on. Have the possibility. That is, the condensed water obtained by condensing the cathode exhaust, the burner exhaust, and the like by the condenser is normally accumulated in the tank and used as timely reformed water. In this way, the supply of reformed water by condensed water without receiving supply of makeup water such as tap water from outside is referred to as “water independence”.

  In the operation in this water self-sustained state, the amount of water G1 generated when the fuel supplied to the fuel cell system burns is compared with the amount of water G2 in the plant exhaust, and it is confirmed that G1 ≧ G2.

If there is a shortage of reforming water, irreversible damage may occur in the reformer. Therefore, the amount of water in the tank that accumulates the condensed water is detected to determine whether sufficient water is always available. It is necessary to confirm it. According to the prior art, as shown in Patent Document 1, the amount of water accumulated in the tank is detected by a water level sensor.
Japanese Patent No. 3702827

  By the way, the domestic fuel cell power generation system uses water for reforming as described above, and contains moisture such as cathode exhaust or burner exhaust so that it can be operated without replenishing tap water from the outside. In general, the exhaust gas is condensed by a condenser, and the condensed water is stored in a tank and used. And as shown in the said patent document 1, in order to confirm whether the water quantity in a tank is always ensured, the water level is measured using a water level sensor.

  However, in the configuration shown above, a water level sensor is installed in the tank in order to measure the water level. However, the water level sensor is an expensive measuring instrument, and by providing this measuring instrument, household fuel cell power generation This causes an increase in system cost.

  Therefore, the present invention is inexpensive by measuring the temperature of the plant exhaust with a thermometer instead of the expensive water level sensor used as the prior art, and performing the operation in a water-independent state without detecting the water level. An object of the present invention is to provide a simple fuel cell power generation system.

  In order to achieve the above-described object, the present invention is directed to a condenser that receives an exhaust gas from a cathode of a fuel cell and / or an exhaust gas from a burner and recovers water vapor through an exhaust heat recovery system, and the condenser. In a fuel cell power generation system having a storage tank for accumulating condensed water condensed by the above, an exhaust thermometer for measuring the temperature at the exhaust outlet of the condenser, and circulation of the refrigerant flowing through the exhaust heat recovery system in the condenser An exhaust heat recovery pump that adjusts the amount; and a control unit that controls the rotational speed of the exhaust heat recovery pump based on the temperature measured by the exhaust thermometer, wherein the control unit includes the exhaust thermometer When the temperature at the exhaust outlet of the condenser measured by the above is higher than the temperature necessary for maintaining a water self-sustaining state, the condensed water in the condenser can be reduced by increasing the rotational speed of the exhaust heat recovery pump. And controlling so as to pressure.

  The condenser further includes a refrigerant temperature setting unit that detects a temperature of the refrigerant circulating in the exhaust heat recovery system in the condenser and sets the temperature, and the control unit measures the condenser measured by the exhaust thermometer. When the exhaust outlet temperature of the exhaust gas exceeds a temperature necessary for maintaining the water self-sustained state, the refrigerant temperature setting unit is used to control to lower the set temperature of the refrigerant circulating in the exhaust heat recovery system. This is also an embodiment of the present invention.

  Furthermore, the present invention includes a burner air supply blower that supplies off-gas from the fuel cell to the burner, and the control unit detects the number of rotations of the burner air supply blower to reduce the air supply amount to the burner. Based on the calculated air supply amount, calculates a temperature necessary for maintaining a water self-sustained state, and further includes a cathode air supply blower for supplying air to the cathode, the control unit, Calculating the air supply amount to the cathode by detecting the number of revolutions of the cathode air supply blower, and calculating the temperature necessary to maintain the water self-sustained state based on the calculated air supply amount The point characterized by is also included as one aspect.

  In the above aspect, the temperature of the plant exhaust is measured with an inexpensive exhaust thermometer without providing a water sensor for detecting the water level of the tank that accumulates the condensed water, and it is confirmed whether the water self-sustaining state is realized. can do. Moreover, since the set temperature of the refrigerant circulating in the condenser can be adjusted based on the temperature measured by the exhaust thermometer, it is relatively clear for adjusting the amount of condensed water, which is control of the set temperature of the refrigerant, It becomes possible to establish a water independence state by an easy means.

  Furthermore, the amount of air supplied to the burner or cathode is calculated from the rotational speed of the burner or cathode air supply blower, and the exhaust temperature required for realizing water self-sustainment is calculated based on the amount of air, so that more accurate A high amount of condensed water is detected, and a water self-sustaining state can be maintained. That is, since sufficient condensed water can be supplied to the reformer, there is no possibility of irreversible damage to the reformer due to water shortage, and a fuel cell power generation system with high circulation efficiency can be provided.

  According to the present invention as described above, is the water self-sustained state realized by measuring the temperature of the plant exhaust with an inexpensive exhaust thermometer without providing a water sensor for detecting the water level of the tank that accumulates the condensed water? Since it is possible to confirm whether or not, it is possible to reduce the cost of the fuel cell power generation system.

[First embodiment]
[Constitution]
FIG. 1 shows a fuel cell power generation system including a condenser 3 according to a first embodiment to which the present invention is applied. Although the configuration of the present embodiment will be described in detail below, the present invention is characterized by the condenser and its surroundings, and therefore the configuration of a general fuel cell main body, reformer, and the like is omitted.

As shown in FIG. 1, in the present embodiment, the cathode exhaust, which is an electrode on the air side, is extracted as part of the fuel cell main body in order to send the cathode exhaust to the condenser 3 described later. That is, the cathode exhaust is sent from the cathode 1 to the condenser 3 through a gas flow path connected to the condenser 3. In addition, since the reaction at the cathode 1 is [2H ++ 2e ⁻ + 1 / 2O ₂ → H ₂ O], hydrogen ions, electrons, and oxygen are combined to generate water. That is, it is considered that the exhaust gas from the cathode 1 contains a sufficient amount of moisture.

  Next, a burner 2 is provided for burning off-gas from the fuel cell body, that is, exhaust from the fuel-side anode in the fuel cell body and hydrogen remaining in the cell body. The burner 2 is used as a heating source for maintaining the reaction because the reforming reaction in the reformer is an adsorption reaction.

  The burner 2 is connected to the condenser 3 through a gas flow path, and burner exhaust generated by air burning using residual hydrogen as fuel is sent to the condenser 3. Here, the burner exhaust burns hydrogen and anode exhaust, which are fuels, as described above, so there is a high possibility that water vapor is contained, and it flows into the condenser 3 and condenses to condense water. It can be taken out.

  As shown in FIG. 1, a cathode exhaust from the cathode 1 and a burner exhaust from the burner 2 are sent out, and a condenser 3 that generates condensed water by condensing these is provided. The condenser 3 is generally used as a fuel cell power generation system, but an exhaust thermometer 4 for measuring the temperature of the plant exhaust is installed at an exhaust outlet 3a in the condenser. The point that this exhaust thermometer 4 is installed at the exhaust outlet 3a and the temperature of the plant exhaust is measured is a technical feature of the present embodiment, and water independence is confirmed based on the measured temperature.

  Here, the exhaust thermometer 4 uses a thermistor as an example, and in particular, an NTC thermistor having a negative coefficient and decreasing in resistance value when the temperature rises is used. That is, in the prior art, the amount of condensed water generated by the condenser is detected by a water level sensor, whereas the present invention is an exhaust thermometer 4 that is less expensive than a water level sensor, in particular, a thermistor for plant exhaust. Measuring temperature.

  The condenser 3 is provided with a refrigerant flow path 3b in the same manner as a general one. The refrigerant circulates in the flow path 3b, so that the cathode exhaust sent into the condenser 3 and The burner exhaust is cooled and condensed. The refrigerant flow path 3b is equipped with an exhaust heat recovery pump 5 to adjust the circulation of the refrigerant in the refrigerant flow path 3b. That is, it is possible to obtain a large amount of condensed water by adjusting the refrigerant circulation amount by changing the rotation speed of the exhaust heat recovery pump 5 and maintaining the water self-sustaining state.

  And in this structure, of course, the storage tank 6 which accumulate | stores the condensed water condensed in the condenser 3 is provided. In FIG. 1, the storage tank 6 is provided in the lower part of the condenser 3, but the present invention is not limited to this aspect, and the installation and configuration are not specified as long as the condensed water can be stored. .

  In the present embodiment, a control unit 7 is provided that controls the rotational speed of the exhaust heat recovery pump 5 based on the temperature of the plant exhaust gas detected by the exhaust thermometer 4. The controller 7 increases the amount of condensed water condensed by the condenser 3 when the temperature of the plant exhaust gas measured by the exhaust gas thermometer 4 is higher than the temperature necessary for the water self-sustained state. Control is performed to increase the rotational speed of the pump 5. That is, by increasing the number of revolutions of the exhaust heat recovery pump 5, the amount of circulating refrigerant flowing in the refrigerant flow path 3b is increased, thereby controlling to recover a large amount of condensed water.

  On the other hand, when the temperature of the plant exhaust gas measured by the exhaust thermometer 4 is lower than the temperature necessary for the water self-sustained state, the amount of condensed water condensed by the condenser 3 for maintaining the water self-sustained state is stored. Since it can be considered that it is accumulated in the tank 6, there is no need to increase the rotational speed of the exhaust heat recovery pump 5.

As shown in FIG. 5, the temperature for realizing the water self-sustained state is, for example, when the fuel is supplied at 3 NL / min and the plant exhaust is discharged at 54 NL / min, the amount of water generated by the reaction of the fuel is The amount of fuel supplied, the number of carbon atoms, and the molecular weight of water from the reaction formula of the fuel cell main body are integrated and converted to grams, which is 5.8 g / min. On the other hand, the amount of water included in the plant exhaust is 5.8 g / min when the moisture level of the plant exhaust is 12% and the water pressure is 0.13 kg / cm ² . The saturation temperature at this time is 50 ° C.

  That is, the amount of water generated by the reaction of the fuel is 5.8 g / min (G1) and the amount of water contained in the plant exhaust is 5.8 kg / min (G2), or the amount of water generated by the reaction of the fuel is the plant exhaust. Since the water self-sustained state is established more than the amount of water contained, and the saturation temperature at which the water content is the same is 50 ° C., this temperature is the temperature in the water self-sustained state. That is, in this example, it is possible to establish a water self-sustained state when the exhaust temperature is 50 ° C., and the temperature of the plant exhaust actually measured by the exhaust thermometer 4 is 50 ° C. or less at which the water self-sustained temperature is reached. In this case, a sufficient amount of water for maintaining water self-sustainability can be secured by the condenser 3 (G1 ≧ G2).

  On the other hand, when the temperature of the plant exhaust actually measured by the exhaust thermometer 4 exceeds the water self-sustained temperature of 50 ° C., the amount of condensed water supplied as the amount of water G1 generated by the reaction of the fuel is not sufficient. As a result, the water self-supporting state is not maintained (G1 <G2). Therefore, the control unit 7 controls to increase the rotational speed of the exhaust heat recovery pump 5 and increases the amount of condensed water in the condenser 3 to achieve a water self-sustained state.

[Action]
The operation of the present embodiment having the above-described configuration is as follows.
First, at least one of the cathode exhaust from the cathode 1 or the burner exhaust from the burner 2 is sent to the condenser 3, and the temperature of these exhausts is lowered by the refrigerant circulating in the refrigerant flow path 3b in the condenser 3, Condensed water accumulates in the storage tank 6 by condensing a part of the moisture contained in the exhaust gas. Here, the temperature of the plant exhaust is measured by the exhaust thermometer 4 installed at the plant exhaust outlet 3 a of the condenser 3.

  And the control part 7 judges whether this measured temperature is higher than the temperature required for water independence, and in order to increase the amount of condensed water condensed by the condenser 3 in the case of being high, Control is performed to increase the rotational speed of the exhaust heat recovery pump 5. That is, when the temperature of the plant exhaust gas measured is higher than the temperature required for water self-sustainment, it means a situation where water self-sustainment is not realized. Therefore, the refrigerant flow path can be increased by increasing the rotational speed of the exhaust heat recovery pump 5. Control is performed so as to realize a water self-sustained state by increasing the circulation amount of the refrigerant flowing in 3b and thereby collecting a large amount of condensed water. As a result, the controlled exhaust heat recovery pump 5 operates to increase the rotation speed, and by increasing the refrigerant circulation amount, a large amount of condensed water is accumulated in the tank 6 to establish a water self-sustaining state.

[effect]
In the present embodiment having the above-described configuration, the temperature of the plant exhaust is measured by the inexpensive exhaust thermometer 4 without providing a water sensor for detecting the water level of the tank that accumulates condensed water, thereby realizing a water self-sustained state Therefore, it is possible to reduce the cost of the fuel cell power generation system. That is, by installing the exhaust thermometer 4 at the exhaust outlet 3 a of the condenser 3, it becomes possible to maintain water self-sustainability at the measured temperature, so that the condensation that serves as a part of a household fuel cell power generation system An inexpensive and useful configuration can be provided.

[Second Embodiment]
[Constitution]
FIG. 2 shows a fuel cell power generation system equipped with a condenser according to a second embodiment to which the present invention is applied. The peripheral configuration of the condenser 3 of the first embodiment is partially changed. It is. The configuration of this embodiment is as follows.

  In FIG. 2, as in the first embodiment shown in FIG. 1, the cathode exhaust extracted as part of the fuel cell main body in order to send the cathode exhaust to the condenser 3, and the anode exhaust and the fuel cell main body remain. A burner 2 is provided that generates burner exhaust for burning the fuel and the like to be sent to the condenser 3. The condenser 3 is provided with a plant exhaust outlet 3a and a refrigerant flow path 3b through which the refrigerant circulates as in a general case, and an exhaust heat recovery pump 5 is attached to the refrigerant flow path 3b. Further, an exhaust thermometer 4 for measuring the temperature of the plant exhaust is attached to the exhaust outlet 3 a in the condenser 3, and a storage tank 6 for accumulating condensed water condensed by the condenser 3 is installed. Is the same as that of the first embodiment.

  In the present embodiment, in addition to the configuration similar to those in FIG. 1, the temperature of the refrigerant circulating in the refrigerant flow path 3b in the condenser 3 is detected, and the refrigerant temperature setting unit 8 to be set is attached to the refrigerant flow path 3b. Has been. The refrigerant temperature setting unit 8 collects a large amount of condensed water when the temperature of the plant exhaust measured by the exhaust thermometer 4 installed at the exhaust outlet 3a of the condenser 3 is equal to or higher than the water self-sustained temperature. The control temperature of the refrigerant circulating through the refrigerant flow path 3b is controlled to be lowered to a predetermined temperature.

  That is, in this embodiment, by providing the refrigerant temperature setting unit 8, the control unit 7 circulates the refrigerant flow path 3 b through the refrigerant temperature setting unit 8 based on the temperature of the plant exhaust measured by the exhaust thermometer 4. Adjust the refrigerant temperature. Specifically, as described above, when the temperature of the plant exhaust measured by the exhaust thermometer 4 is equal to or higher than the temperature necessary for realizing the water self-sustained state, the fuel cell power generation system can be reused. Since the condensed water is insufficient, the control unit 7 causes the refrigerant temperature setting unit 8 to lower the temperature of the refrigerant so as to collect a large amount of condensed water.

  That is, by reducing the temperature of the refrigerant circulating in the condenser 3, it becomes possible to further cool the cathode exhaust and the burner exhaust, and an increase in the amount of condensed water accumulated in the tank 6 can be expected. it can. On the other hand, when the temperature of the plant exhaust measured by the exhaust thermometer 4 is lower than the temperature necessary for realizing the water self-sustained state, the condensed water to be reused in the fuel cell power generation system is insufficient. However, since the water self-sustaining state is maintained, the controller 7 does not need to reduce the temperature of the refrigerant through the refrigerant temperature setting unit 8.

[Action]
The operation of the present embodiment having the above-described configuration is as follows.
First, as in the first embodiment having the configuration of FIG. 1, at least one of the cathode exhaust from the cathode 1 or the burner exhaust from the burner 2 is sent to the condenser 3, and the refrigerant flow path in the condenser 3 The temperature is lowered by the refrigerant circulating in 3b, and a part of the moisture contained in the exhaust is condensed and accumulated in the storage tank 6. Here, the temperature of the plant exhaust is measured by the exhaust thermometer 4 installed at the plant exhaust outlet 3 a of the condenser 3.

  And the control part 7 judges whether this measured temperature is higher than the temperature required for water independence, and in order to increase the amount of condensed water condensed by the condenser 3 in the case of being high, Control is performed to lower the set temperature of the refrigerant circulating in the refrigerant flow path 3b through the refrigerant temperature setting unit 8. That is, by reducing the temperature of the refrigerant to a predetermined temperature through the refrigerant temperature setting unit 8 and further cooling the exhaust gas from the cathode 1 and the burner 2 sent into the condenser 3, the necessary amount of condensed water is stored in the storage tank 6. It is stored inside and controlled to achieve a water independence state.

  Thereby, the controlled refrigerant temperature setting unit 8 operates so as to lower the set temperature of the refrigerant circulating in the refrigerant flow path 3b to a predetermined temperature, and condenses the cathode exhaust gas and the burner exhaust gas by increasing the condensation amount. Strive to collect water and establish a water self-sustaining state in the fuel cell power generation system.

[effect]
In the present embodiment having the above-described configuration, the temperature of the plant exhaust is measured by the inexpensive exhaust thermometer 4 without installing an expensive water level sensor for detecting the water level in the storage tank 6 that accumulates condensed water. By doing so, it is possible to confirm whether the water self-sustained state is realized or not, and thus it is possible to reduce the cost of the fuel cell power generation system. Further, since the set temperature of the refrigerant circulating in the condenser 3 can be adjusted based on the temperature measured by the exhaust thermometer 4, the adjustment of the condensed water amount, which is control of the set temperature of the refrigerant, is relatively clear. Thus, it becomes possible to establish a water self-supporting state by an easy means.

[Third embodiment]
[Constitution]
FIG. 3 shows a fuel cell power generation system equipped with a condenser according to a third embodiment to which the present invention is applied. The peripheral configuration of the condenser 3 of the first and second embodiments is partially changed. It is a thing. The configuration of this embodiment is as follows.

  In FIG. 3, as in the first and second embodiments shown in FIGS. 1 and 2, the cathode 1 extracted as part of the fuel cell main body to send the cathode exhaust to the condenser 3, the anode exhaust and the fuel A burner 2 is provided that generates burner exhaust for burning fuel remaining in the battery body and sending it to the condenser 3. The condenser 3 is provided with a plant exhaust outlet 3a and a refrigerant flow path 3b through which the refrigerant circulates as in a general case, and an exhaust heat recovery pump 5 is attached to the refrigerant flow path 3b.

  Further, an exhaust thermometer 4 for measuring the temperature of the plant exhaust is attached to the exhaust outlet 3a in the condenser 3, and the temperature of the refrigerant circulating in the refrigerant flow path 3b is detected and set as a refrigerant temperature setting. The point where the part 8 is provided is the same as that of the second embodiment. In addition, the structure which has installed the storage tank 6 which accumulate | stores the condensed water condensed by the condenser 3 is the same as 1st and 2nd embodiment.

  In addition to the configurations similar to those in FIGS. 1 and 2, the present embodiment is characterized in that a burner air supply blower 9 is installed in the middle of a gas flow path from the fuel cell main body to the burner 2. The burner air supply blower 9 is a blower capable of obtaining a static pressure higher than that of the fan, and sucks residual hydrogen and anode exhaust from the fuel cell main body and sends them to the burner 2.

  Here, the control unit 7 is also connected to the burner air supply blower 9, estimates the air supply amount to the burner 2 from the rotational speed of the burner air supply blower 9, and the condenser based on the estimated burner air amount. The plant exhaust temperature required for the water self-sustaining state in 3 is estimated. That is, the control unit 7 calculates the water self-supporting temperature based on the air amount to the burner 2 estimated from the rotation speed of the burner air supply blower 9, and the temperature actually measured by the exhaust thermometer 4 is the water temperature. When the temperature exceeds the self-sustaining temperature, the rotational speed of the exhaust heat recovery pump 5 is increased, or control is performed to decrease the temperature of the refrigerant through the refrigerant temperature setting unit 8.

  That is, the amount of condensed water in the condenser 3 is determined by the ratio of gases other than water in the gas sent to the condenser 3 and the condensation temperature. In this embodiment, the control unit 7 calculates the amount of air 2 to the burner. As a result, the amount of gas other than water flowing into the condenser 3 is calculated, and the exhaust outlet temperature necessary for water self-supporting, which is a criterion for adjusting the amount of condensed water, is calculated.

[Action]
The operation of the present embodiment having the above-described configuration is as follows.
In the present embodiment, first, the burner exhaust from the burner 2 is sent to the condenser 3, the temperature is lowered by the refrigerant circulating in the refrigerant flow path 3 b in the condenser 3, and one of the moisture contained in the exhaust As the part condenses, it is accumulated in the storage tank 6.

  Here, the control unit 7 calculates the air supply amount to the burner 2 from the rotational speed via the burner air supply blower 9. Further, the control unit 7 calculates the amount of gas other than water flowing into the condenser 3 by calculating the amount of air to the burner 2 via the burner air supply blower 9, and the condenser necessary for water self-supporting. 3 is calculated. Further, the temperature of the plant exhaust is also measured by the exhaust thermometer 4 installed at the plant exhaust outlet 3 a of the condenser 3.

  In addition, since the amount of condensed water in the condenser 3 is determined by the gas ratio other than water in the gas and the condensation temperature, for example, when a large amount of gas other than water is present, the set temperature of the refrigerant decreases or the exhaust heat recovery pump A predetermined amount of condensed water cannot be obtained unless the temperature of condensation is lowered by increasing the number of revolutions of the refrigerant 5 by increasing the circulation amount of the refrigerant and reducing the moisture content in the exhaust gas. That is, if a predetermined amount of condensed water cannot be obtained, the balance between the amount of water generated by the combustion of fuel and the amount of water in the plant exhaust is lost, and a state of G1 <G2 is established, making water independence impossible.

  Therefore, the control unit 7 calculates the amount of gas other than water flowing into the condenser 3 by calculating the amount of air to the burner 2 via the burner air supply blower 9, and the condenser 3 necessary for water self-supporting. The amount of condensed water is adjusted based on the temperature of the plant exhaust actually measured by the exhaust thermometer 4.

  Specifically, the control unit 7 determines whether or not the measured temperature is higher than the calculated temperature necessary for water self-supporting, and if it is higher, the amount of condensed water condensed by the condenser 3 In order to increase this, control is performed so as to decrease the set temperature of the refrigerant circulating in the refrigerant flow path 3b or to increase the rotational speed of the exhaust heat recovery pump 5. That is, the burner 2 that flows into the condenser 3 by increasing the circulation amount of the refrigerant by lowering the temperature of the refrigerant to a predetermined temperature through the refrigerant temperature setting unit 8 or increasing the rotational speed of the exhaust heat recovery pump 5. The amount of condensed water required is accumulated in the storage tank 6 by further cooling the gas from the water, and control is performed so as to realize a water self-sustaining state.

  Thus, the controlled refrigerant temperature setting unit 8 operates to lower the set temperature of the refrigerant circulating in the refrigerant flow path 3b to a predetermined temperature, or the exhaust heat recovery pump 5 operates to increase the rotation speed. Then, the amount of burner exhaust condensation is increased by increasing the amount of refrigerant circulation, and the water self-sustaining state in the fuel cell power generation system is established.

[effect]
In the present embodiment having the above-described configuration, the temperature of the plant exhaust is provided without providing a water level sensor for detecting the water level in the storage tank 6 that accumulates condensed water, as in the first and second embodiments. Is measured by the inexpensive exhaust thermometer 4, so that the cost of the fuel cell power generation system can be reduced.

  Further, the amount of air supplied to the burner 2 is calculated from the number of revolutions of the burner air supply blower 9, and the exhaust temperature necessary for realizing water self-sustainment is calculated based on the amount of air. The amount of water is detected, and it becomes possible to maintain a water independence state. That is, since sufficient condensed water can be supplied to the reformer, there is no possibility of irreversible damage to the reformer due to water shortage, and a fuel cell power generation system with high circulation efficiency can be provided.

[Fourth Embodiment]
[Constitution]
FIG. 4 shows a fuel cell power generation system equipped with a condenser according to a fourth embodiment to which the present invention is applied. The peripheral configuration of the condenser 3 of the first and second embodiments is partially changed. It is a thing. The configuration of this embodiment is as follows.

  In FIG. 4, as in the first and second embodiments shown in FIGS. 1 and 2, the cathode 1 extracted as part of the fuel cell main body to send the cathode exhaust to the condenser 3, the anode exhaust, and the fuel A burner 2 is provided that generates burner exhaust for burning fuel remaining in the battery body and sending it to the condenser 3. The condenser 3 is provided with a plant exhaust outlet 3a and a refrigerant flow path 3b through which the refrigerant circulates as in a general case, and an exhaust heat recovery pump 5 is attached to the refrigerant flow path 3b.

  Further, an exhaust thermometer 4 for measuring the temperature of the plant exhaust is attached to the exhaust outlet 3a in the condenser 3, and the temperature of the refrigerant circulating in the refrigerant flow path 3b is detected and set as a refrigerant temperature setting. The point where the part 8 is provided is the same as that of the second embodiment. In addition, the structure which has installed the storage tank 6 which accumulate | stores the condensed water condensed by the condenser 3 is the same as 1st and 2nd embodiment.

  In addition to the same configuration as those in FIGS. 1 and 2, the present embodiment is characterized in that a cathode air supply blower 10 is installed in the middle of a gas flow path to the cathode 1. This cathode air supply blower 10 is a blower capable of obtaining a static pressure larger than that of the fan, like the burner air supply blower, and sucks air to be supplied to the cathode 1 and sends the air to the cathode 1. It is.

  Here, the control unit 7 is also connected to the cathode air supply blower 10, estimates the air supply amount to the cathode 1 from the number of rotations of the cathode air supply blower 10, and the condenser based on the estimated cathode air amount. The plant exhaust temperature required for the water self-sustaining state in 3 is estimated. That is, the control unit 7 calculates the water self-supporting temperature based on the amount of air to the cathode 1 estimated from the rotation speed of the cathode air supply blower 10, and the temperature actually measured by the exhaust thermometer 4 is the water temperature. When the temperature exceeds the self-sustaining temperature, the rotational speed of the exhaust heat recovery pump 5 is increased, or control is performed to decrease the temperature of the refrigerant through the refrigerant temperature setting unit 8.

  That is, since the amount of condensed water in the condenser 3 is determined by the ratio of gases other than water in the gas sent to the condenser 3 and the condensation temperature, the control unit 7 calculates the air amount of the cathode 1 in this embodiment. Thus, the amount of gas other than water flowing into the condenser 3 is calculated, and the exhaust outlet temperature necessary for water self-supporting, which is a criterion for adjusting the amount of condensed water, is calculated.

  On the other hand, when the temperature actually measured by the exhaust thermometer 4 does not exceed the water self-sustained temperature, the rotational speed of the exhaust heat recovery pump 5 is increased or the refrigerant temperature is lowered through the refrigerant temperature setting unit 8. It is not necessary to control, and this state is maintained because water independence is established.

[Action]
The operation of the present embodiment having the above-described configuration is as follows.
In this embodiment, first, the cathode exhaust from the cathode 1 is sent to the condenser 3, and the temperature is lowered by the refrigerant circulating in the refrigerant flow path 3 b in the condenser 3, so that one of the moisture contained in the exhaust Condensed water accumulates in the storage tank 6 as the part condenses.

  Here, the control unit 7 calculates the air supply amount to the cathode 1 from the rotational speed via the cathode air supply blower 10. Further, the control unit 7 calculates the amount of gas other than water flowing into the condenser 3 by calculating the amount of air to the cathode 1 via the cathode air supply blower 10, and the condenser necessary for water self-supporting. 3 is calculated. Further, the temperature of the plant exhaust is measured by the exhaust thermometer 4 installed at the plant exhaust outlet 3a of the condenser 3.

  In addition, since the amount of condensed water in the condenser 3 is determined by the gas ratio other than water in the gas and the condensation temperature, for example, when a large amount of gas other than water is present, the set temperature of the refrigerant decreases or the exhaust heat recovery pump A predetermined amount of condensed water cannot be obtained unless the temperature of condensation is lowered by increasing the number of revolutions of the refrigerant 5 by increasing the circulation amount of the refrigerant and reducing the moisture content in the exhaust gas. That is, if a predetermined amount of condensed water cannot be obtained, the balance between the amount of water generated by the combustion of fuel and the amount of water in the plant exhaust is lost, and a state of G1 <G2 is established, making water independence impossible.

  Therefore, the control unit 7 calculates the amount of gas other than water flowing into the condenser 3 by calculating the amount of air to the cathode 1 via the cathode air supply blower 10, and the condenser 3 necessary for water self-supporting. The amount of condensed water is adjusted based on the temperature of the plant exhaust actually measured by the exhaust thermometer 4.

  Specifically, the control unit 7 determines whether or not the measured temperature is higher than the calculated temperature necessary for water self-supporting, and if it is higher, the amount of condensed water condensed by the condenser 3 In order to increase this, control is performed so as to decrease the set temperature of the refrigerant circulating in the refrigerant flow path 3b or to increase the rotational speed of the exhaust heat recovery pump 5. That is, the burner 2 that flows into the condenser 3 by increasing the circulation amount of the refrigerant by lowering the temperature of the refrigerant to a predetermined temperature through the refrigerant temperature setting unit 8 or increasing the rotational speed of the exhaust heat recovery pump 5. The amount of condensed water required is accumulated in the storage tank 6 by further cooling the gas from the water, and control is performed so as to realize a water self-sustaining state.

  Thus, the controlled refrigerant temperature setting unit 8 operates to lower the set temperature of the refrigerant circulating in the refrigerant flow path 3b to a predetermined temperature, or the exhaust heat recovery pump 5 operates to increase the rotation speed. Then, by increasing the refrigerant circulation amount, the amount of condensation of the burner exhaust is increased, and the water self-sustaining state in the fuel cell power generation system is established.

[effect]
In the present embodiment having the above-described configuration, the temperature of the plant exhaust is provided without providing a water level sensor for detecting the water level in the storage tank 6 that accumulates condensed water, as in the first to third embodiments. Is measured by the inexpensive exhaust thermometer 4, so that the cost of the fuel cell power generation system can be reduced.

  Further, the amount of air supplied to the burner 2 is calculated from the number of revolutions of the cathode air supply blower 10, and the exhaust temperature necessary for realizing water self-sustainment is calculated based on the amount of air. The amount of water is detected, and it becomes possible to maintain a water independence state. That is, since sufficient condensed water can be supplied to the reformer, it is possible to provide a fuel cell power generation system with high circulation efficiency without causing irreversible damage to the reformer due to water shortage.

[Other Embodiments]
In addition, this invention is not limited to the above embodiments, The following embodiment is also included. In the third embodiment and the fourth embodiment described above, the fuel cell power generation system includes the burner air supply blower 9 and the cathode air supply blower 10 respectively. In the present embodiment, the burner air supply is provided. It has a configuration including both the blower 9 and the cathode air supply blower 10.

  That is, the burner air supply blower 9 is installed in the middle of the gas flow path from the fuel cell main body to the burner 2, and the cathode air supply blower 10 is installed in the middle of the gas flow path to the cathode 1. The operation of the fuel cell power generation system having such a configuration is as follows.

  In the present embodiment, first, the exhaust gas from the cathode 1 and the burner 2 is sent to the condenser 3, and the temperature is lowered by the refrigerant circulating in the refrigerant flow path 3 b in the condenser 3, so that the moisture contained in the exhaust gas Condensed water is accumulated in the storage tank 6 as a part of the water is condensed.

  Here, the control unit 7 calculates the air supply amount to the burner 2 from the rotational speed via the burner air supply blower 9, and further from the rotational speed to the cathode 1 via the cathode air supply blower 10. The air supply amount is also calculated. And the said control part 7 calculates gas amount other than the water which flows into the condenser 3 by calculating the air quantity to the burner 2 and the cathode 1 via the burner air supply blower 9 and the cathode air supply blower 10. Then, the exhaust outlet temperature of the condenser 3 necessary for water self-supporting is calculated. Further, the temperature of the plant exhaust is measured by the exhaust thermometer 4 installed at the plant exhaust outlet 3a of the condenser 3.

  In addition, since the amount of condensed water in the condenser 3 is determined by the gas ratio other than water in the gas and the condensation temperature, for example, when a large amount of gas other than water is present, the set temperature of the refrigerant decreases or the exhaust heat recovery pump A predetermined amount of condensed water cannot be obtained unless the temperature of condensation is lowered by increasing the number of revolutions of the refrigerant 5 by increasing the circulation amount of the refrigerant and reducing the moisture content in the exhaust gas. That is, if a predetermined amount of condensed water cannot be obtained, the balance between the amount of water generated by the combustion of fuel and the amount of water in the plant exhaust is lost, and a state of G1 <G2 is established, making water independence impossible. Therefore, the control unit 7 calculates the amount of gas other than water flowing into the condenser 3 by calculating the amount of air to the burner 2 and the cathode 1 via the burner air supply blower 9 and the cathode air supply blower 10. The exhaust outlet temperature of the condenser 3 necessary for water self-supporting is obtained, and the amount of condensed water is adjusted based on the temperature of the plant exhaust actually measured by the exhaust thermometer 4.

  Specifically, the control unit 7 determines whether or not the measured temperature is higher than the calculated temperature necessary for water self-supporting, and if it is higher, the amount of condensed water condensed by the condenser 3 In order to increase this, control is performed so as to decrease the set temperature of the refrigerant circulating in the refrigerant flow path 3b or to increase the rotational speed of the exhaust heat recovery pump 5. That is, the burner 2 that flows into the condenser 3 by increasing the circulation amount of the refrigerant by lowering the temperature of the refrigerant to a predetermined temperature through the refrigerant temperature setting unit 8 or increasing the rotational speed of the exhaust heat recovery pump 5. Further, by controlling the exhaust gas from the cathode 1 to be further cooled, the necessary amount of condensed water is accumulated in the storage tank 6 so as to realize a water self-sustaining state.

  Thus, the controlled refrigerant temperature setting unit 8 operates to lower the set temperature of the refrigerant circulating in the refrigerant flow path 3b to a predetermined temperature, or the exhaust heat recovery pump 5 operates to increase the rotation speed. Then, by increasing the refrigerant circulation amount, the condensation amount of the burner exhaust and the cathode exhaust is increased, and the water self-sustaining state in the fuel cell power generation system is established.

Configuration diagram of the first embodiment of the present invention Configuration diagram of second embodiment of the present invention Configuration diagram of third embodiment of the present invention The block diagram of the 4th Embodiment of this invention Reaction example showing water self-supporting state of the present invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Cathode 2 ... Burner 3 ... Condenser 3a ... Exhaust outlet 3b ... Refrigerant flow path 4 ... Exhaust thermometer 5 ... Exhaust heat recovery pump 6 ... Storage tank 7 ... Control part 8 ... Refrigerant temperature setting part 9 ... Burner air supply blower 10 ... Cathode air supply blower

Claims (10)

The exhaust gas from the cathode of the fuel cell and / or the exhaust gas from the burner is flowed in, and has a condenser for recovering water vapor through an exhaust heat recovery system, and a storage tank for storing the condensed water condensed by the condenser In the fuel cell power generation system,
An exhaust thermometer for measuring the temperature of the exhaust outlet of the condenser;
An exhaust heat recovery pump for adjusting the circulation amount of the refrigerant flowing through the exhaust heat recovery system in the condenser;
A controller that controls the number of revolutions of the exhaust heat recovery pump based on the temperature measured by the exhaust thermometer,
The control unit increases the rotational speed of the exhaust heat recovery pump when the temperature of the exhaust outlet of the condenser measured by the exhaust thermometer exceeds a temperature necessary for maintaining a water self-sustaining state. The fuel cell power generation system is controlled to increase the condensed water in the condenser. A refrigerant temperature setting unit for detecting the temperature of the refrigerant circulating in the exhaust heat recovery system in the condenser and setting the temperature;
The control unit circulates the exhaust heat recovery system through the refrigerant temperature setting unit when the exhaust outlet temperature of the condenser measured by the exhaust thermometer exceeds a temperature necessary for maintaining a water self-sustained state. 2. The fuel cell power generation system according to claim 1, wherein control is performed so as to lower a set temperature of the refrigerant to be performed. A burner air supply blower for supplying off-gas from the fuel cell to the burner;
The control unit calculates the air supply amount to the burner by detecting the rotational speed of the burner air supply blower, and is necessary for maintaining a water self-sustained state based on the calculated air supply amount. The fuel cell power generation system according to claim 1, wherein the temperature is calculated. A cathode air supply blower for supplying air to the cathode;
The control unit calculates the air supply amount to the cathode by detecting the number of rotations of the cathode air supply blower, and is necessary for maintaining a water self-sustained state based on the calculated air supply amount. The fuel cell power generation system according to claim 1, wherein the temperature is calculated. The control unit, when the exhaust outlet temperature of the condenser measured by the exhaust thermometer exceeds the temperature for maintaining the water self-supporting state calculated through the burner air supply blower and / or the cathode supply blower In addition, by increasing the number of rotations of the exhaust heat recovery pump, control to increase the condensed water in the condenser,
Alternatively, the fuel cell power generation system according to claim 3, wherein control is performed to reduce a set temperature of the refrigerant circulating in the exhaust heat recovery system through the refrigerant temperature setting unit. The exhaust gas from the cathode of the fuel cell and / or the exhaust gas from the burner is flowed in and has a condenser for recovering water vapor through an exhaust heat recovery system and a storage tank for storing the condensed water condensed by the condenser. In the control method of the fuel cell power generation system,
An exhaust thermometer that measures the temperature of the exhaust outlet of the condenser, and
An exhaust heat recovery pump for adjusting the circulation amount of the refrigerant flowing through the exhaust heat recovery system in the condenser;
Based on the temperature measured by the exhaust thermometer, a control step for controlling the rotational speed of the exhaust heat recovery pump is performed,
The control step increases the rotation speed of the exhaust heat recovery pump when the temperature of the exhaust outlet of the condenser measured by the exhaust thermometer exceeds a temperature necessary for maintaining a water self-sustained state. A control method for a fuel cell power generation system, characterized in that control is performed to increase the condensed water in the condenser. A refrigerant temperature setting unit for detecting the temperature of the refrigerant circulating in the exhaust heat recovery system in the condenser and setting the temperature;
The control step circulates the exhaust heat recovery system through the refrigerant temperature setting unit when the exhaust outlet temperature of the condenser measured by the exhaust thermometer exceeds a temperature necessary for maintaining a water self-sustained state. The control method for a fuel cell power generation system according to claim 6, wherein control is performed so as to lower a set temperature of the refrigerant to be performed. A burner air supply blower for supplying off-gas from the fuel cell to the burner;
The control step calculates the air supply amount to the burner by detecting the number of revolutions of the burner air supply blower, and is necessary for maintaining a water self-sustaining state based on the calculated air supply amount. The method of controlling a fuel cell power generation system according to claim 6 or 7, wherein the temperature is calculated. A cathode air supply blower for supplying air to the cathode;
The control step calculates the air supply amount to the cathode by detecting the number of rotations of the cathode air supply blower, and is necessary for maintaining the water self-sustained state based on the calculated air supply amount. The method of controlling a fuel cell power generation system according to claim 6 or 7, wherein the temperature is calculated. In the control step, when the exhaust outlet temperature of the condenser measured by the exhaust thermometer exceeds a temperature for maintaining a water self-supporting state calculated through the burner air supply blower and / or the cathode supply blower. In addition, by increasing the number of rotations of the exhaust heat recovery pump, control to increase the condensed water in the condenser,
Alternatively, the control method of the fuel cell power generation system according to claim 8 or 9, wherein the control is performed to reduce a set temperature of the refrigerant circulating in the exhaust heat recovery system through the refrigerant temperature setting unit.

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