JP2005158597A - Faults detection system of combustor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fault detection system in which the faults of a combustor can be detected surely with a simple structure. <P>SOLUTION: In the fault detection system of the combustor which is installed at the combustor 1 in which an anode off-gas 5 and cathode off-gas 3 are burnt and in which the faults of the combustor 1 is detected, a first combustion catalyst 13, a first thermometer 23, a second combustion catalyst 15, and a second thermometer 25 are arranged in the combustor 1 in this order along flows of the off-gases 3, 5, and a detection temperature range of the second thermometer 25 is established at a higher temperature side than that of the first thermometer 23. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

The present invention relates to an abnormality detection system for a combustor, and more particularly to an abnormality detection system for detecting an abnormality in combustion of a combustor disposed in a fuel cell system.

  In general, in a fuel cell, hydrogen gas that is a fuel gas is supplied to an anode, air that is an oxidizing gas is supplied to a cathode, an oxidation-reduction reaction is caused by these hydrogen gas and air, and the resulting chemical energy is directly converted into electricity. Extract as energy.

Further, hydrogen is contained in the anode off-gas discharged from the anode side, and if the anode off-gas is discharged as it is to the outside air, the environment may be adversely affected. For this reason, a combustor that mixes and burns anode off-gas and cathode off-gas is disposed so that the anode off-gas is burned and discharged to the outside air (see, for example, Patent Document 1).
JP-A-2-5367

  However, in the prior art, it is difficult to detect deterioration of the combustion catalyst in the combustor, abnormal combustion, failure of the temperature sensor itself, etc., so it is confirmed whether the combustor is operating normally. It was difficult to do.

  Accordingly, an object of the present invention is to provide an abnormality detection system for a combustor that can detect an abnormality of the combustor with a simple structure.

  In order to achieve the above object, a combustor abnormality detection system according to the present invention is provided in a combustor that burns anode off-gas and cathode off-gas discharged from a fuel cell, and detects the combustor abnormality. In this abnormality detection system, the first combustion catalyst, the first temperature detection means, the second combustion catalyst, and the second temperature detection means are arranged in the combustor in the order along the flow of the off-gas. And the temperature range detected by the second temperature detecting means is set higher than the temperature range detected by the first temperature detecting means.

  According to the abnormality detection system for a combustor according to the present invention, the detection temperature range of the second temperature detection means is set on the higher temperature side than the detection temperature range of the first temperature detection means. The width of the detected temperature range in the temperature detecting means and the second temperature detecting means can be substantially narrowed. Therefore, the detection temperature range is set in the temperature range corresponding to the combustion temperature of each combustion catalyst, and accurate temperature detection with little measurement error can be performed.

  A combustor abnormality detection system according to an embodiment of the present invention will be described below with reference to the drawings.

  FIG. 1 is a cross-sectional view schematically showing a combustor provided with the abnormality detection system. This combustor 1 includes an introduction part 7 for introducing a cathode off gas 3 and an anode off gas 5, a mixing part 9 disposed on the downstream side of the gas flow of the introduction part 7, and a first power source 11 connected to a power source 11. An electrothermal catalyst that is the combustion catalyst 13 and a second combustion catalyst 15 disposed on the downstream side of the first combustion catalyst 13 are provided, and the first combustion catalyst 13 is provided between the mixing section 9 and the first combustion catalyst 13. A space 17 is formed, a second space 19 is formed between the first combustion catalyst 13 and the second combustion catalyst 15, and a third space is formed downstream of the second combustion catalyst 15. A space portion 21 is formed. The lengths of the second space portion 19 and the third space portion 21 along the gas flow direction are preferably 20 mm, 30 mm, or the like, for example. Further, the cell density (number of cells per square centimeter) of the first combustion catalyst 13 is set smaller than the cell density of the second combustion catalyst 15. For example, when a metal catalyst is used as the first combustion catalyst 13 and a metal / ceramic catalyst is used as the second combustion catalyst 15, the cell density per unit area in the first combustion catalyst 13 may be set to 300 CPSI. The cell density per unit area in the second combustion catalyst 15 can be set to 600/900 CPSI. Thus, it is preferable to set the cell density of the second combustion catalyst 15 to about 2 to 3 times the cell density of the first combustion catalyst 13.

  Further, on the upper side of the second space portion 19 and the third space portion 21, a first thermometer 23 which is a first temperature detecting means and a second thermometer 25 which is a second temperature detecting means are provided. Is provided. The measurement temperature range in the first thermometer 23 is set on the lower temperature side than the second thermometer 25. For example, the measurement temperature range in the first thermometer 23 can apply a range of −100 ° C. to 600 ° C., and the measurement temperature range of the second thermometer 25 can apply a range of 400 ° C. to 1200 ° C. .

  Next, the gas flow inside the combustor 1 will be described.

  First, the cathode offgas 3 and the anode offgas 5 discharged from a fuel cell (not shown) are fed into the introduction unit 7, mixed in the mixing unit 9, and become a combustion mixed gas 31. The combustion mixed gas 31 is combusted through the first combustion catalyst 13 and the second combustion catalyst 15, and then becomes combustion exhaust gas 33 and is discharged from the combustor 1.

  Next, the combustor abnormality detection system according to the present embodiment will be described with reference to FIG. Note that the measured temperature value measured by the first thermometer 23 is T1, the measured temperature value measured by the second thermometer 25 is T2, and the appropriate temperature when the first combustion catalyst 13 burns normally is Tα is an appropriate temperature when the second combustion catalyst 15 burns normally. And the appropriate temperature range in each combustion catalyst 13 and 15 shall be Tα ± 15% and Tβ ± 15% in this embodiment. This Tα ± 15% indicates a temperature range of Tα × 0.85 to Tα × 1.15. However, since this appropriate temperature range can be changed as appropriate according to the type of catalyst used in the combustor, the flow rate of off-gas, and the like, in this embodiment, it is set to ± 15% as an example thereof.

  First, it is determined whether or not the combustor 1 is in steady combustion (S1). If the combustor 1 is in steady combustion, the temperature is measured by the first thermometer 23 and the second thermometer 25. In addition, proper temperatures Tα and Tβ that are normally assumed by the first thermometer 23 and the second thermometer 25 are calculated (S2). On the other hand, when the combustor 1 is not in steady combustion, the operation of the system is terminated. .

  Next, T1 is compared with Tα ± 15% (S3), and if T1 is less than Tα × 0.85, the process proceeds to step 4 (S4). In step 4, T2 is compared with Tβ ± 15%.

  Here, when T2 is less than Tβ × 0.85, it is determined that not only the first combustion catalyst 13 but also the second combustion catalyst 15 is performing abnormally low temperature combustion (S13). In this case, there is a possibility that both combustion catalysts 13 and 15 are not combusting due to an abnormality such as deterioration, an abnormality such as an excessive air supply amount or an insufficient fuel supply amount has occurred.

  Further, when the measured value of T2 is Tβ × 0.85 or more, it is determined that the first combustion catalyst 13 is abnormally low temperature combustion (S5). That is, when T2 exceeds Tβ × 0.85 to Tβ × 1.15 and Tβ × 1.15, the first combustion catalyst 13 has deteriorated, and therefore, the combustion is performed at abnormally low temperature. Judge that

  Further, when T1 is higher than Tα × 1.15, T2 is compared with Tβ ± 15% (S6). Here, when T2 is less than Tβ × 0.85 and Tβ × 0.85-Tβ × 1.15, it is determined that the first thermometer 23 is abnormal (S7). This is because when the first combustion catalyst 13 is burning at an abnormally high temperature, the second combustion catalyst 15 is also likely to perform an abnormally high temperature combustion, so only the first combustion catalyst 13 is abnormal. The fact that the second combustion catalyst 15 exhibits normal combustion or an abnormally low temperature combustion state due to high temperature combustion means that the first thermometer 23 is in an abnormal state due to failure, deterioration with time, or the like.

  When T2 is higher than Tβ × 1.15, it is determined that the first combustion catalyst 13 and the second combustion catalyst 15 are abnormally high temperature combustion (S8). This is because, as described above, when the first combustion catalyst 13 is performing abnormally high temperature combustion, the second combustion catalyst 15 is also likely to perform abnormally high temperature combustion. The causes of abnormally high temperature combustion include an excessive amount of fuel supplied and an insufficient amount of air to be supplied.

  If T1 is Tα × 0.85 to Tα × 1.15, T2 is compared with Tβ ± 15% (S9). Here, when T2 is less than Tβ × 0.85, it is determined that the second combustion catalyst 15 is deteriorated and performing abnormally low temperature combustion (S10). This is because when the first combustion catalyst 13 performs normal combustion, the second combustion catalyst 15 hardly performs abnormally high temperature combustion, and performs normal combustion or abnormally low temperature combustion. Therefore, in the case of step 10, it is determined that only the second combustion catalyst 15 is performing abnormally low temperature combustion due to deterioration, poor self-heating, or the like.

  When T2 is higher than Tβ × 1.15, it is determined that the second thermometer 25 is abnormal (S11). This is because, when the first combustion catalyst 13 is performing normal combustion, there is almost no possibility that only the second combustion catalyst 15 performs abnormally high temperature combustion, so that it is determined that the second thermometer 25 is abnormal. It is.

  When T2 is Tβ × 0.85 to Tβ × 1.15, it is determined that the combustor 1 operates normally and normal combustion is performed (S12), and whether or not steady combustion is being performed again. Is determined (S1). The above diagnosis result is transmitted to a control means (not shown) to perform an abnormality process.

  Below, the effect by this embodiment is demonstrated.

  Since the detection temperature range of the second thermometer 25 is set higher than the detection temperature range of the first thermometer 23 and corresponds to the combustion temperature of each combustion catalyst, temperature detection with little measurement error is performed. be able to.

  That is, the second combustion catalyst 15 is disposed downstream of the first combustion catalyst 13, the combustion temperature of the first combustion catalyst 13 is measured by the first thermometer 23, and the combustion of the second combustion catalyst 15 is performed. Although the temperature is measured by the second thermometer 25, the combustion temperature of the second combustion catalyst 15 is higher than the combustion temperature of the first combustion catalyst 13. Therefore, by setting the second thermometer 25 to a high detection temperature range, the width of the detection temperature range is substantially narrowed, and a thermometer with little measurement error and high durability is obtained, and the width of the detection temperature range is substantially reduced. The cost of the thermometer can also be reduced by narrowing it. The first thermometer 23 is also set to a low detection temperature range, so that the width of the detection temperature range is substantially narrowed. Therefore, the same effect as the second thermometer 25 can be obtained.

  Furthermore, in order to improve the detection accuracy of the combustion temperature of each combustion catalyst 13, 15, two thermometers are arranged on the downstream side of the first combustion catalyst 13 and 2 on the downstream side of the second combustion catalyst 15. A method of arranging two thermometers is also conceivable, but there are problems such as a complicated structure and increased costs. Therefore, as in this embodiment, by arranging one thermometer 23 and 25 for each combustion catalyst 13 and 15, respectively, the combustion temperature of each combustion catalyst 13 and 15 can be efficiently and reliably set. Can be detected.

  In addition, since the cell density in the first combustion catalyst 13 is set smaller than the cell density in the second combustion catalyst 15, the combustion temperature in each combustion catalyst 13, 15 can be detected accurately. That is, since the combustion catalyst is likely to be clogged with moisture, normal combustion does not occur in the combustion catalyst, and the detection accuracy of the combustion temperature may be lowered. However, according to the present embodiment, the cell density of the first combustion catalyst 13 is increased to make the eyes coarser, and water is easily discharged from the first combustion catalyst 13. The combustion temperature by the catalyst 13 can be accurately detected. Further, since the temperature is sufficiently increased by the first combustion catalyst 13, the second combustion catalyst 15 can perform combustion without being affected by moisture. Since the second combustion catalyst 15 is set to a normal cell density, the second combustion catalyst 15 can reliably burn the fuel that could not be processed by the first combustion catalyst 13. Therefore, the overall combustion efficiency of the combustion catalyst 13 and the second combustion catalyst 15 is not lowered.

1 is a cross-sectional view schematically showing a combustor provided with an abnormality detection system according to an embodiment of the present invention. It is a flowchart which shows the processing flow of the abnormality detection system which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Combustor 3 ... Cathode off gas 5 ... Anode off gas 13 ... 1st combustion catalyst 15 ... 2nd combustion catalyst 23 ... 1st thermometer (1st temperature detection means)
25 ... 2nd thermometer (2nd temperature detection means

Claims (8)

In a combustor abnormality detection system that is provided in a combustor that combusts anode off-gas and cathode off-gas discharged from a fuel cell and detects abnormality of the combustor,
A first combustion catalyst, a first temperature detection means, a second combustion catalyst, and a second temperature detection means are arranged in the combustor in the order along the gas flow of the off gas, and the first combustion catalyst, 2. An abnormality detection system for a combustor, wherein the temperature detection range of the second temperature detection means is set to be higher than the temperature detection range of the first temperature detection means. Calculating an appropriate temperature range indicated by the first temperature detecting means and the second temperature detecting means when the first combustion catalyst and the second combustion catalyst are normally burned;
When the measurement value by the first temperature detection means exceeds the appropriate temperature range and the measurement value by the second temperature detection means exceeds the appropriate temperature range, the first combustion catalyst and the second combustion catalyst The abnormality detection system for a combustor according to claim 1, wherein the abnormal combustion is determined to be abnormal high temperature combustion.   When the measured value by the first temperature detecting means is less than the appropriate temperature range and the measured value by the second temperature detecting means is less than the appropriate temperature range, the first combustion catalyst and the second combustion catalyst The abnormality detection system for a combustor according to claim 2, wherein both of the abnormal low temperature combustion are determined.   If the measured value by the first temperature detecting means is less than the appropriate temperature range and the measured value by the second temperature detecting means is within the appropriate temperature range or exceeds the appropriate temperature range, the first combustion The combustor abnormality detection system according to claim 2, wherein the abnormality is determined to be abnormal low temperature combustion of the catalyst.   If the measured value by the first temperature detecting means exceeds the appropriate temperature range and the measured value by the second temperature detecting means does not exceed the appropriate temperature range, the first temperature detecting means is abnormal. The abnormality detection system for a combustor according to any one of claims 2 to 4, characterized by:   When the measured value by the first temperature detecting means is within the range of the appropriate temperature range and the measured value by the second temperature detecting means is less than the appropriate temperature range, the abnormally low temperature combustion of the second combustion catalyst It is judged that it is. The abnormality detection system of the combustor of any one of Claims 2-5 characterized by the above-mentioned.   If the measured value by the first temperature detecting means is within the appropriate temperature range and the measured value by the second temperature detecting means exceeds the appropriate temperature range, the second temperature detecting means is abnormal. The abnormality detection system for a combustor according to any one of claims 2 to 6, wherein the abnormality detection system is determined. The abnormality detection system for a combustor according to any one of claims 1 to 7, wherein a cell density in the first combustion catalyst is set smaller than a cell density in the second combustion catalyst.

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