Fuel cell tail gas measuring system and fuel cell

Abstract

The utility model relates to the technical field of fuel cells, and particularly provides a fuel cell tail gas measuring system and a fuel cell. The fuel cell tail gas measuring system comprises a heat exchange unit, a gas outlet pipeline, a water-gas separator and a measuring pipeline. Wherein the heat exchange unit is internally provided with a refrigeration channel used for being communicated with the electric pile tail discharge unit, and tail gas discharged from the electric pile tail discharge unit is cooled and dehumidified by the refrigeration channel and then is conveyed to the water-gas separator through the gas outlet pipeline; the measuring pipeline is communicated with a gas outlet of the water-gas separator, and a gas measuring device is arranged on the measuring pipeline and is used for detecting the flow of gas flowing through the measuring pipeline and the concentration of hydrogen in the gas. According to the fuel cell tail gas measuring system, the influence of condensate water on the measurement of the gas measuring device can be avoided, and the measurement accuracy of the gas measuring device on the hydrogen content in the gas can be improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to fuel cell technical field, especially a kind of fuel cell tail gas measuring system. BACKGROUND

[0002] Fuel cell normal operation, the tail gas discharged from the outlet of electric pile, also called humidity, mainly includes hydrogen, gaseous water and a small amount of nitrogen. In order to realize the correct evaluation of hydrogen content in fuel cell (electric pile) tail gas, and then provide strong data support for performance verification of fuel cell, the content of hydrogen and other components in the tail gas of fuel cell needs to be accurately measured and analyzed.

[0003] However, due to the large amount of water vapor in the tail gas, when the humidity of the tail gas reaches 100%, part of the water vapor exists in the form of condensed water, which greatly affects the measurement of tail gas flow and the accuracy of the measurement of hydrogen and other components in the tail gas. In the prior art, there is no feasible solution to measure the flow of mixed gas with different humidity using a single flow meter at high temperature. For the case where the tail gas contains condensed water and the humidity is uncertain, it is difficult to measure the flow and component concentration of the mixed gas. Therefore, it is necessary to develop a system suitable for fuel cell tail gas measurement, and to improve the problem of poor measurement accuracy caused by water vapor in the tail gas. SUMMARY

[0004] Therefore, the utility model aims at providing a kind of fuel cell tail gas measuring system to improve the accuracy of hydrogen content measurement in fuel cell tail gas.

[0005] To achieve the above purpose, the technical scheme of the utility model is as follows:

[0006] A kind of fuel cell tail gas measuring system, including heat exchange unit, outlet pipeline, water-gas separator and measuring pipeline;The refrigeration channel for connecting the electric pile tail exhaust unit is provided in the heat exchange unit, and the tail gas discharged from the electric pile tail exhaust unit is cooled and dehumidified by the refrigeration channel and then delivered to the water-gas separator by the outlet pipeline.

[0007] The measuring pipeline is connected to the gas outlet of the water-gas separator, and the gas measuring device is provided on the measuring pipeline, which is used to detect the gas flow and hydrogen concentration in the gas flowing through the measuring pipeline.

[0008] Further, the heat exchange unit comprises a shell, and a semiconductor refrigerating sheet arranged in the inner cavity of the shell, the semiconductor refrigerating sheet divides the inner cavity of the shell into the refrigerating channel and the heating channel; the cold end heat conduction fin of the semiconductor refrigerating sheet is arranged in the refrigerating channel, and the hot end heat conduction fin of the semiconductor refrigerating sheet is arranged in the heating channel; the tail end of the measuring pipeline is communicated with the heating channel, and the heating channel is connected with a backflow pipeline for discharging gas; the fuel cell tail gas measuring system further comprises a backwater pipeline communicated between the water outlet of the water-gas separator and the heating channel.

[0009] Further, the power supply of the semiconductor refrigerating sheet is adjustable.

[0010] Further, the refrigerating channel is arranged in the middle of the inner cavity of the shell, the heating channel comprises a left heating channel and a right heating channel arranged on the two sides of the refrigerating channel respectively; the semiconductor refrigerating sheet is arranged between the left heating channel and the refrigerating channel and between the right heating channel and the refrigerating channel.

[0011] Further, the backwater pipeline is provided with a first flow meter.

[0012] Further, the backflow pipeline is provided with a first temperature sensor and a first pressure sensor.

[0013] Further, the bottom of the heating channel is further communicated with a humidification pipeline for discharging accumulated water, the tail end of the humidification pipeline is communicated with the backflow pipeline, the humidification pipeline is provided with a heater, and the backflow pipeline between the humidification pipeline and the heating channel is provided with an adjusting valve.

[0014] Further, the gas measuring device comprises a second flow meter, a second temperature sensor, a second pressure sensor and a hydrogen concentration sensor arranged on the measuring pipeline.

[0015] Further, the stack tail exhaust unit and the refrigerating channel are communicated through a tail gas pipeline, and the tail gas pipeline is provided with a third temperature sensor, a first hygrometer and a third pressure sensor.

[0016] Compared with the prior art, the utility model has the following advantages:

[0017] (1) the fuel cell tail gas measuring system of the utility model, through setting up heat exchange unit in the system, utilize the refrigerating channel in the heat exchange unit to remove the water in the gas, make the humidity of the gas that flow through the measuring pipeline drop, will not appear the condensation situation, avoided the influence that the water content measured to the gas measuring device, can greatly promote the measurement accuracy of the gas measuring device to the hydrogen content in the gas.

[0018] (2) The adoption of semiconductor refrigerating sheet in the heat exchange unit can well realize the heat transfer between the refrigeration channel and the heating channel. The cold end heat conduction fin of the semiconductor refrigerating sheet can effectively reduce the temperature in the refrigeration channel to achieve the purpose of dehumidification. The hot end heat conduction fin of the semiconductor refrigerating sheet can heat the heating channel to evaporate the water flowing into the heating channel into gas state. The gas flow after measurement is transported to the heating channel, and the water separated by the water-gas separator is also returned to the heating channel. By using the heating and humidifying effect of the heating channel, the gas discharged from the return pipeline can be restored to the initial composition state of the tail gas, so as to be analyzed, processed and utilized subsequently. The tail gas containing hydrogen can also be supplied to the stack gas supply unit under suitable humidity conditions for reuse.

[0019] (3) By adjusting the power supply power, the temperature in the refrigeration channel can be well controlled to ensure that the dehumidification effect meets the measurement requirements. By adjusting the operating power of the semiconductor refrigerating sheet, the temperature of the gas flowing through the measurement pipeline can be controlled to be lower than the ambient temperature by 5℃ or less, so that the water contained in the cooled gas in the measurement pipeline exists in gas state and does not affect the measurement due to condensation.

[0020] (4) The two semiconductor refrigerating sheets are arranged relatively to divide the inner cavity of the shell into a left heating channel, a refrigeration channel and a right heating channel. This not only facilitates the arrangement of the semiconductor refrigerating sheet and its fins, but also well realizes the temperature control effect of the refrigeration channel and the heating channel.

[0021] (5) The first flow meter arranged on the return water pipeline can accurately measure the amount of separated water. Combined with the gas measurement structure of the gas measurement device on the measurement pipeline, the total water content in the tail gas discharged by the stack tail discharge unit can be calculated.

[0022] (6) The first temperature sensor and the first pressure sensor arranged on the return pipeline can detect the temperature and pressure of the gas discharged by the system in real time to understand the temperature and pressure conditions of the return and reuse gas.

[0023] (7) In view of the situation that water that cannot be completely evaporated will be accumulated in the heating channel, a humidification pipeline is arranged at the bottom of the heating channel. The heater on the humidification pipeline can heat and evaporate the water to humidify the return gas in the form of water vapor, realizing the full utilization of the condensed water. The adjustment valve can adjust the flow resistance of the gas path in the return pipeline to ensure that the upstream and downstream sides have appropriate pressure difference, so that the steam from the humidification pipeline can smoothly enter the return pipeline, and the accumulated water in the heating channel can also flow into the humidification pipeline and be heated and evaporated by the heater.

[0024] (8) The second flow meter, the second temperature sensor, the second pressure sensor and the hydrogen concentration sensor are arranged in the gas measuring device, so that the flow, temperature, pressure and hydrogen concentration of the gas flowing through the measuring pipeline can be measured, and the content of hydrogen, nitrogen and other components in the gas can be calculated.

[0025] (9) The third temperature sensor, the first temperature and humidity meter and the third pressure sensor are arranged on the tail gas pipeline, so that the temperature, humidity and pressure of the tail gas entering the heat exchange unit can be detected in real time, which provides effective reference basis for the regulation of the semiconductor refrigerating sheet and the temperature and pressure control of the gas in the measuring pipeline. Meanwhile, the second temperature sensor is arranged on the measuring pipeline, so that the temperature of the airflow in the measuring pipeline can be detected in real time, and the temperature difference measured by the second temperature sensor and the third temperature sensor can provide reference for the regulation of the semiconductor refrigerating sheet.

[0026] Another purpose of the utility model lies in providing a fuel cell, which adopts the fuel cell tail gas measuring system. DRAWINGS

[0027] The drawings constituting a part of the utility model are used to provide further understanding of the utility model, and the schematic embodiment and the description thereof are used to explain the utility model, wherein the front and back, the up and down and other orientation words are only used to express relative position relationship, and all do not constitute improper limitation on the utility model. In the drawings:

[0028] Figure 1 The system structure schematic view of the fuel cell tail gas measuring system is shown in the drawings;

[0029] Figure 2 The cross section structure schematic view of the heat exchange unit shown in the part A-A is shown in the drawings; Figure 1

[0030] Figure 3 The structure schematic view of the fuel cell tail gas measuring system in another pipeline arrangement form is shown in the drawings.

[0031] Mark explanation:

[0032] 1, tail gas pipeline; 10, stack tail exhaust unit; 11, third temperature sensor; 12, first temperature and humidity meter; 13, third pressure sensor;

[0033] 2, backflow pipeline; 20, stack gas supply unit; 21, first temperature sensor; 22, first pressure sensor; 23, regulating valve;

[0034] ​3, heat exchange unit; 30, shell; 31, semiconductor refrigeration sheet; 311, cold end heat conduction fin; 312, hot end heat conduction fin; 32, power supply; 33, refrigeration channel; 341, left heating channel; 342, right heating channel; 343, communication channel;

[0035] 4, water gas separator; 40, air outlet pipeline;

[0036] 5, measurement pipeline; 50, second flow meter; 51, second temperature sensor; 52, second pressure sensor; 53, hydrogen concentration sensor;

[0037] 6, backwater pipeline; 60, first flow meter; 61, first backwater branch; 62, second backwater branch;

[0038] 7, heater; 70, humidification pipeline. DETAILED DESCRIPTION

[0039] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0040] In the description of the present application, it should be declared that if the terms indicating the orientation or position relationship such as "up, down, left, right, front, back, inside and outside" appear, they are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present application, and cannot be understood as the limitation of the present application.

[0041] Furthermore, in the description of the utility model, unless otherwise explicitly limited, the terms "mounting", "connecting", "connection", "connector" should be understood broadly. For example, the connection can be fixed connection, or detachable connection, or integrally connected; can be mechanical connection, or electrical connection; can be directly connected, or indirectly connected through intermediate medium, or the communication inside two elements. For ordinary skilled in the art, the specific meaning of the above terms in the utility model can be understood in combination with specific circumstances. In the description of the utility model, the limiting terms such as "first", "second", "A", "B", "C", "D" and the like appear, which are only for distinguishing the same features of different positions, attributions or uses, to avoid ambiguity and confusion, and cannot be understood as indicating or implying relative importance. In addition, the semiconductor refrigerating sheet mentioned in the embodiment of the utility model is a new type of cooling device that achieves refrigeration by using Peltier effect, which has the characteristics of no vibration noise, no refrigerant, real-time temperature control, controllable temperature difference range, etc. When direct current passes through the electric couple formed by the series connection of two different semiconductor materials, the cold end heat conduction fin and the hot end heat conduction fin that absorb heat and release heat respectively can be formed at the two ends of the electric couple, the cold end heat conduction fin can realize refrigeration, and the hot end heat conduction fin can realize heating.

[0042] The utility model will be described in detail below with reference to the drawings and in combination with embodiments.

[0043] Embodiment one

[0044] The embodiment relates to a fuel cell tail gas measuring system, which can improve the accuracy of hydrogen content measurement in fuel cell tail gas; an exemplary system configuration is as shown in the figure. Figure 1 As shown in the figure.

[0045] Overall, the fuel cell tail gas measuring system comprises a heat exchange unit 3, an outlet pipeline 40, a water-gas separator 4 and a measuring pipeline 5. The heat exchange unit 3 is provided with a refrigeration channel 33 for communicating with the stack tail exhaust unit 10, and the tail gas discharged from the stack tail exhaust unit 10 is cooled and dehumidified by the refrigeration channel 33 and then delivered to the water-gas separator 4 through the outlet pipeline 40. The measuring pipeline 5 communicates with the gas outlet of the water-gas separator 4, and the measuring pipeline 5 is provided with a gas measuring device; the gas measuring device is used to detect the gas flow and the hydrogen concentration in the gas flowing through the measuring pipeline 5.

[0046] It should be pointed out that based on the overall design idea, the technical scheme of the utility model can adopt various different specific implementation structures, forms or configuration sequences. For example, the heat exchange unit 3 can adopt the mode of circulating refrigerant compressed by a compressor in a closed system to realize the preparation of cold and hot temperature difference conditions, and can also adopt the semiconductor refrigerating sheet 31 to realize the preparation of cold and hot temperature difference conditions. The connection assembly mode, sequence and the like of the heat exchange unit 3, the water-gas separator 4, the measuring pipeline 5 and the backwater pipeline 6 can also be flexibly adjusted. For the parts required for the overall scheme implementation but not involved in the overall setting, reasonable and flexible design can be made according to the mature setting means in the field, the actual situation during implementation and the like. The specific implementation scheme of the embodiment is only one of the many schemes formed by the above various combinations and changes, and in actual implementation, the technical personnel in the field can make flexible adjustment and improvement according to the actual situation. Obviously, the various specific form combinations and changes can form many schemes, and the specific implementation scheme of the embodiment is within the protection scope of the utility model.

[0047] In the embodiment, as shown in Figure 2 The heat exchange unit 3 comprises a shell 30 and a semiconductor refrigerating sheet 31 arranged in the inner cavity of the shell 30, and the semiconductor refrigerating sheet 31 divides the inner cavity of the shell 30 into a refrigeration passage 33 and a heating passage; the cold end heat conduction fin 311 of the semiconductor refrigerating sheet 31 is arranged in the refrigeration passage 33, and the hot end heat conduction fin 312 of the semiconductor refrigerating sheet 31 is arranged in the heating passage.

[0048] The semiconductor refrigerating sheet 31 is adopted in the heat exchange unit 3, which can well realize the heat transfer between the refrigeration passage 33 and the heating passage, the cold end heat conduction fin 311 of the semiconductor refrigerating sheet 31 can effectively reduce the temperature in the refrigeration passage 33 to achieve the purpose of dehumidification, and the hot end heat conduction fin 312 of the semiconductor refrigerating sheet 31 can heat the heating passage to evaporate the water flowing into the heating passage into a gaseous state to achieve the purpose of humidifying the gas.

[0049] Based on the above setting, the end of the measuring pipeline 5 of the embodiment is communicated with the heating passage, and the heating passage is connected with a backflow pipeline 2 for discharging gas; the fuel cell tail gas measuring system further comprises a backwater pipeline 6 communicated between the water outlet of the water-gas separator 4 and the heating passage. The gas flow after measurement is transported to the heating passage, and the water separated by the water-gas separator 4 is also backflowed to the heating passage, and the heating and humidifying effect of the heating passage can restore the gas discharged by the backflow pipeline 2 to the initial component state of the tail gas, so as to be analyzed, processed and utilized subsequently; the tail gas containing hydrogen can also be supplied to the stack gas supply unit 20 again under suitable humidity conditions.

[0050] Of course, the semiconductor refrigeration sheet 31 is equipped with a power supply 32 for power supply, and preferably, the power supply 32 is configured in an adjustable form for the power supply of the semiconductor refrigeration sheet 31. By adjusting the power supply of the power supply 32, the temperature in the refrigeration channel 33 can be well controlled to ensure that the dehumidification effect meets the requirements of the measurement. In actual implementation, by regulating the operating power of the semiconductor refrigeration sheet 31, the temperature of the airflow flowing through the measurement pipeline 5 (i.e. the temperature measured by the second temperature sensor 51 described below) is controlled to be lower than the ambient temperature by 5℃ or less, which can ensure that the moisture contained in the cooled gas in the measurement pipeline 5 exists in a gaseous state and does not appear to affect the measurement

[0051] Of course, there are many different structure schemes for the number, form, etc. of the semiconductor refrigeration sheet 31. In the embodiment, as shown in Figure 2 two groups of semiconductor refrigeration sheets 31 are oppositely arranged in the shell 30. Among them, the refrigeration channel 33 is arranged in the middle of the inner cavity of the shell 30, and the heating channels include left and right heating channels 341 and 342 arranged on both sides of the refrigeration channel 33, respectively; the left and right heating channels 341 and 342 and the refrigeration channel 33 are both provided with semiconductor refrigeration sheets 31. Oppositely arranging two semiconductor refrigeration sheets 31 can well separate the inner cavity of the shell 30 into the left heating channel 341, the refrigeration channel 33 and the right heating channel 342, which not only facilitates the arrangement of the semiconductor refrigeration sheet 31 and its fins, but also well realizes the temperature control effect of the refrigeration channel 33 and the heating channel.

[0052] It should be pointed out that the left and right heating channels 341 and 342 are both heating channels, and the two are preferably connected by a communication channel 343, as shown in Figure 2 one communication channel 343 is arranged at the top and bottom of the shell 30 to communicate the left and right heating channels 341 and 342.

[0053] Of course, the communication channel 343 can also not be arranged, and then the left and right heating channels 341 and 342 are separated into two parts in the inner cavity of the shell 30; in this case, as shown in Figure 3As shown, the first return water branch 61 and the second return water branch 62 can be arranged at the end of the return water pipeline 6 to respectively communicate with the left heating channel 341 and the right heating channel 342. Of course, when the left heating channel 341 and the right heating channel 342 are separated into two parts in the inner cavity of the shell 30, the gas discharged from the measuring pipeline 5 should also be delivered into the left heating channel 341 and the right heating channel 342 through the separated branches, and finally the humidified gas in the left heating channel 341 and the right heating channel 342 should be output through the return flow branches and finally converge into the return flow pipeline 2 to be discharged from the return flow pipeline 2 to the gas supply unit 20 of the fuel cell stack, or used for subsequent analysis, processing and utilization.

[0054] As shown in the drawings, Figure 1 The gas measuring device of the embodiment includes the second flow meter 50, the second pressure sensor 52 and the hydrogen concentration sensor 53 arranged on the measuring pipeline 5. By arranging the second flow meter 50, the second pressure sensor 52 and the hydrogen concentration sensor 53 in the gas measuring device, the flow rate, pressure and hydrogen concentration of the gas flowing through the measuring pipeline 5 can be measured, and the hydrogen content in the gas can be calculated.

[0055] Furthermore, the stack exhaust unit 10 and the refrigeration channel 33 of the embodiment are communicated through the tail gas pipeline 1, and the third temperature sensor 11, the first hygrometer 12 and the third pressure sensor 13 are arranged on the tail gas pipeline 1, and the gas measuring device further includes the second temperature sensor 51 arranged on the measuring pipeline 5. By arranging the third temperature sensor 11, the first hygrometer 12 and the third pressure sensor 13 and other measuring elements on the tail gas pipeline 1, the temperature, humidity and pressure of the tail gas entering the heat exchange unit 3 can be detected in real time, which provides effective reference basis for the subsequent regulation of the semiconductor refrigeration sheet 31 and the temperature and pressure control of the gas in the measuring pipeline 5. Meanwhile, the second temperature sensor 51 is arranged on the measuring pipeline 5 to detect the temperature of the gas flow in the measuring pipeline 5 in real time, and the temperature difference between the temperatures detected by the second temperature sensor 51 and the third temperature sensor 11 is used as a reference for the regulation of the semiconductor refrigeration sheet 31, so that the temperature of the gas at the second temperature sensor 51 can be controlled to be lower than the temperature of the external environment by 5℃ or less.

[0056] As shown in the drawings, Figure 1 The first flow meter 60 is arranged on the return water pipeline 6. The first flow meter 60 arranged on the return water pipeline 6 can accurately measure the amount of separated water, and the total water content in the tail gas discharged from the stack exhaust unit 10 can be calculated in combination with the gas measuring structure of the gas measuring device on the measuring pipeline 5.

[0057] In order to transport the backflow gas discharged from the heat exchange unit 3 to the fuel cell, the backflow pipeline 2 is connected between the stack gas supply unit 20 and the heating channel of the embodiment, and the first temperature sensor 21 and the first pressure sensor 22 are arranged on the backflow pipeline 2. By arranging the detection elements such as the first temperature sensor 21 and the first pressure sensor 22 on the backflow pipeline 2, the temperature and pressure of the gas discharged from the system can be detected in real time, and the temperature and pressure conditions of the backflow gas can be understood.

[0058] It should be noted that the water discharged from the backflow pipeline 6 into the heating channel cannot be completely evaporated, so there is accumulated water at the bottom of the heating channel. Therefore, the humidification pipeline 70 for discharging the accumulated water can be connected to the bottom of the heating channel. As shown in Figure 1 The end of the humidification pipeline 70 of the embodiment is connected to the backflow pipeline 2, and the humidification pipeline 70 is provided with a heater 7; at the same time, the adjusting valve 23 is arranged on the backflow pipeline 2 between the humidification pipeline 70 and the heating channel.

[0059] In view of the situation that the water that cannot be completely evaporated is accumulated in the heating channel, the humidification pipeline 70 is arranged at the bottom of the heating channel, and the heater 7 on the humidification pipeline 70 is used to heat and evaporate the water. The accumulated water can be humidified into steam and added to the backflow gas, so that the condensed water can be fully utilized. The adjusting valve 23 can adjust the flow resistance of the gas path in the backflow pipeline 2, so that the upstream and downstream sides have appropriate pressure differences, so that the steam from the humidification pipeline 70 can smoothly enter the backflow pipeline 2, and the accumulated water in the heating channel can flow into the humidification pipeline 70 and be heated and evaporated by the heater 7.

[0060] Based on the above arrangement, the fuel cell tail gas measurement system of the embodiment can measure the content and flow of each component of the gas discharged from the stack, and can send the generated water back to the backflow gas. Considering that the gas needs to be dehumidified during the flow measurement, the heat exchange unit 3 of the embodiment uses a semiconductor refrigerating sheet 31 to realize the functions of first cooling and then heating the gas, so that the flow measurement can be realized while the condensed water is heated and humidified again, and the comprehensive energy consumption of the refrigeration and heating of the whole measurement process is reduced.

[0061] For the heat exchange unit 3, in addition to the semiconductor refrigerating sheet 31 itself, the cold end heat conduction fin 311 and the hot end heat conduction fin 312 and the shell 30 are preferably made of 316L stainless steel, or titanium alloy or other materials that are not easy to contaminate moisture, so as to reduce the ion precipitation of the equipment itself and contaminate the gas. The pipeline such as the tail gas pipeline 1, the backflow pipeline 2, the measurement pipeline 5, the backwater pipeline 6 and the heater 7 is also preferably made of 316L stainless steel, titanium alloy or other materials.

[0062] When the whole system is running, the adjustable power supply 32 receives the voltage adjustment signal through control communication and other means to supply power to the semiconductor refrigeration sheet 31. The temperature difference between the cold end heat conduction fin 311 and the hot end heat conduction fin 312 of the semiconductor refrigeration sheet 31 will change with the voltage and the accumulation of time. At this time, the exhaust gas from the stack enters the refrigeration channel 33 through the exhaust gas pipeline 1 for heat exchange and cooling. The cooled moisture and condensed water generated by cooling enter the water-gas separator 4. The separated gas passes through the measuring pipeline 5 for temperature, pressure, flow rate and hydrogen concentration measurement, and then returns to the heating channel in the heat exchange unit 3 for heating and warming. The gas is warmed up at the same time, taking away part of the liquid water from the water-gas separator 4 through the backwater pipeline 6 into the heating channel. The humidified backflow gas can be reused through the backflow pipeline 2. In addition, the liquid water separated by the water-gas separator 4 enters the heating channel through the backwater pipeline 6, part of which is evaporated at high temperature, and the generated water vapor is taken away by the high-temperature backflow gas. The liquid water that fails to evaporate can be transported to the backflow pipeline 2 through the humidification pipeline 70. In the process of flowing through the humidification pipeline 70, the liquid water is heated and evaporated into gas by the heater 7, mixed with the gas passing through the adjusting valve 23, and the adjusting valve 23 can adjust the flow resistance of the gas path to ensure the appropriate pressure difference before and after the adjustment valve 23, so that the liquid water that fails to evaporate has enough driving force to enter the humidification pipeline 70.

[0063] By reasonably controlling the operating power of the semiconductor refrigeration sheet 31, part of the water in the moisture can be removed through the refrigeration channel 33, and the temperature of the moisture is reduced. When the gas reaches the measuring pipeline 5, the actual operating temperature is controlled to be 5℃ lower than the ambient temperature. The method can achieve the purpose of measuring the flow rate when the humidity is less than 100% without the need for re-warming, and condensation will not occur.

[0064] By measuring the gas flowing through the measuring pipeline 5 with the gas measuring device, the moisture flow rate is directly measured, and the measurement flow rate result is compensated by temperature, pressure and condensed water calculation, so that the flow rate measurement value and the moisture mixed gas composition analysis are more accurate. When the mixed gas passes through the heat exchange unit 3, the temperature at the measuring pipeline 5 is controlled to be about 5℃ lower than the ambient temperature, so that the water vapor at the gas pressure after cooling at this temperature is saturated steam. By looking up the table, the saturated steam pressure of the water vapor in the mixed gas at this time can be known. The hydrogen concentration measured by the hydrogen concentration sensor 53 and the pressure measured by the second pressure sensor 52 can be calculated to obtain the hydrogen partial pressure. The pressure measured by the second pressure sensor 52 minus the hydrogen and water vapor partial pressure can obtain the nitrogen partial pressure. The ideal gas equation can be used to deduce the volume percentage of hydrogen, nitrogen and water vapor, so as to realize the accurate measurement and analysis of the flow rate and composition of the gas flowing through the measuring pipeline 5.

[0065] In summary, the fuel cell tail gas measuring system of the embodiment, by setting the heat exchange unit 3 in the system, the cooling channel 33 in the heat exchange unit 3 is used to cool and dehumidify the tail gas of the stack, so as to remove the moisture in the gas, reduce the humidity of the gas flowing through the measuring pipeline 5, and avoid the influence of condensed water on the measurement of the gas measuring device, which can greatly improve the measurement accuracy of the gas measuring device on the hydrogen content in the gas.

[0066] Embodiment two

[0067] The embodiment relates to a fuel cell which adopts the fuel cell tail gas measuring system provided in embodiment one.

[0068] By adopting the fuel cell tail gas measuring system in the fuel cell system, the cooling channel 33 in the heat exchange unit 3 is used to cool and dehumidify the tail gas of the stack, so as to remove the moisture in the gas, reduce the humidity of the gas flowing through the measuring pipeline 5, and avoid the influence of condensed water on the measurement of the gas measuring device, which can greatly improve the measurement accuracy of the gas measuring device on the hydrogen content in the gas. The gas flow after measurement is delivered to the heating channel, and the water separated by the water-gas separator 4 is also returned to the heating channel. The heating and humidifying effect of the heating channel can supply the tail gas containing hydrogen to the stack gas supply unit 20 again.

[0069] The above is only the preferred embodiment of the utility model, and the detailed configuration explanation, specific structure setting form example, or assembly connection mode expression are all for the need of full disclosure, so that the skilled in the art can better implement the utility model, and not to limit the protection scope of the utility model. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the utility model should be included in the protection scope of the utility model.

Claims

1.A fuel cell tail gas measuring system, characterized in that: it comprises a heat exchange unit (3), an outlet pipeline (40), a water-gas separator (4) and a measuring pipeline (5) ; the heat exchange unit (3) is provided with a refrigeration channel (33) for connecting with a stack tail exhaust unit (10), and the tail gas discharged from the stack tail exhaust unit (10) is cooled and dehumidified by the refrigeration channel (33) and then delivered to the water-gas separator (4) through the outlet pipeline (40) ; the measuring pipeline (5) is connected with an outlet of the water-gas separator (4), and a gas measuring device is arranged on the measuring pipeline (5) for detecting the flow rate of the gas flowing through the measuring pipeline (5) and the hydrogen concentration in the gas. 2.The fuel cell tail gas measuring system according to claim 1, characterized in that: the heat exchange unit (3) comprises a shell (30) and a semiconductor refrigeration sheet (31) arranged in an inner cavity of the shell (30), and the semiconductor refrigeration sheet (31) divides the inner cavity of the shell (30) into the refrigeration channel (33) and a heating channel; the cold end heat conduction fins (311) of the semiconductor refrigeration sheet (31) are arranged in the refrigeration channel (33), and the hot end heat conduction fins (312) of the semiconductor refrigeration sheet (31) are arranged in the heating channel; the end of the measuring pipeline (5) is connected with the heating channel, and the heating channel is connected with a backflow pipeline (2) for discharging gas; the fuel cell tail gas measuring system further comprises a backwater pipeline (6) connected between an outlet of the water-gas separator (4) and the heating channel. 3.The fuel cell tail gas measuring system according to claim 2, characterized in that: the power supply (32) of the semiconductor refrigeration sheet (31) is adjustable. 4.The fuel cell tail gas measuring system according to claim 2, characterized in that: the refrigeration channel (33) is arranged in the middle of the inner cavity of the shell (30), and the heating channel comprises a left heating channel (341) and a right heating channel (342) arranged on the left and right sides of the refrigeration channel (33) respectively; the semiconductor refrigeration sheet (31) is arranged between the left heating channel (341) and the refrigeration channel (33) and between the right heating channel (342) and the refrigeration channel (33). 5.The fuel cell tail gas measuring system according to claim 2, characterized in that: the backwater pipeline (6) is provided with a first flow meter (60). 6.The fuel cell tail gas measuring system according to claim 2, characterized in that: the backflow pipeline (2) is provided with a first temperature sensor (21) and a first pressure sensor (22). 7.The fuel cell tail gas measuring system according to claim 6, characterized in that: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The bottom of the heating channel is also communicated with a humidification pipeline (70) for discharging accumulated water, the end of the humidification pipeline (70) is communicated with the return pipeline (2), a heater (7) is arranged on the humidification pipeline (70), and an adjusting valve (23) is arranged on the return pipeline (2) between the humidification pipeline (70) and the heating channel. 8.The fuel cell exhaust gas measurement system according to any one of claims 1 to 7, characterized in that: The gas measurement device comprises a second flow meter (50), a second temperature sensor (51), a second pressure sensor (52) and a hydrogen concentration sensor (53) arranged on the measurement pipeline (5). 9.The fuel cell exhaust gas measurement system according to claim 8, characterized in that: The stack exhaust unit (10) and the refrigeration channel (33) are communicated through an exhaust pipeline (1), and a third temperature sensor (11), a first hygrometer (12) and a third pressure sensor (13) are arranged on the exhaust pipeline (1). 10.A fuel cell, characterized in that: The fuel cell adopts the fuel cell exhaust gas measurement system according to any one of claims 1 to 9.

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