Hydrogen temperature and humidity controllable test method and system

Abstract

The application belongs to the technical field of hydrogen fuel cells, and specifically provides a hydrogen temperature and humidity controllable testing method and system, wherein the method comprises the following steps: obtaining hydrogen flow into a stack, calculating required flow of humidification water in combination with humidity of required hydrogen into the stack, and calculating required temperature of a plate heat exchanger in combination with temperature of required hydrogen into the stack; mixing and humidifying hydrogen with the required flow of humidification water, and then inputting the hydrogen into a high-temperature intercooler to evaporate; and controlling the temperature of the plate heater according to the required temperature to adjust the temperature of the mixed gas after evaporation and then inputting the mixed gas into the stack. The application can effectively control the temperature and humidity of a hydrogen path subsystem of a fuel cell, and has a good helping effect on performance research of a fuel cell system.

Description

Technical Field

[0001] This invention relates to the field of hydrogen fuel cell technology, and more specifically, to a method and system for controlling the temperature and humidity of hydrogen fuel cells. Background Technology

[0002] Due to the portability of hydrogen fuel cells, they can serve as a power source to replace traditional internal combustion engines in automobiles, making hydrogen energy a commercially valuable new energy development direction for the 21st century. Compared with other renewable energy sources, hydrogen has many advantages, including light weight, easy availability, good thermal conductivity, no pollution, non-toxicity, and high calorific value. Since hydrogen can be produced through water electrolysis, hydrogen energy offers new technological possibilities for long-distance electricity transmission. Its research, development, production, testing, and processing all require the use of test benches. Based on the stack's operating temperature, it can be divided into low-temperature (LT-PEMFC) and high-temperature (HT-PEMFC) stacks. The temperature boundary is generally defined by the boiling point of water at room temperature and pressure, which is 100°C. The coolant medium used is either pure water, a coolant containing ethylene glycol, or a heat transfer oil with a boiling point higher than the stack's operating temperature, respectively. Currently, the testing work conducted on low-temperature stacks far exceeds that on high-temperature stacks.

[0003] Existing patent CN202310222532.9 describes a high-temperature proton exchange membrane fuel cell test bench with a fluid high-low temperature conversion module. This bench utilizes existing low-temperature fuel cell stack testing devices to control the flow rate and pressure of the oxidant and fuel fluid entering the stack. The fluid is initially controlled within the rated maximum temperature of the low-temperature test bench. After passing through the aforementioned conversion module, it is heated to the high-temperature conditions required for entering the high-temperature fuel cell stack. The oxidant and fuel fluid exiting the stack are cooled to a temperature not exceeding the maximum rated temperature of the low-temperature test bench before entering it. The high-temperature coolant from the high-temperature fuel cell stack transfers the high-temperature heat source to the low-temperature test bench via this conversion module. The external cooling source circulating water used in the low-temperature test bench does not directly exchange heat with the coolant from the high-temperature fuel cell stack, reducing the manufacturing complexity of a single unit, shortening the manufacturing cycle, reducing the investment cost of new equipment, and facilitating inspection and maintenance. However, it only controls the gas temperature and does not control the gas humidity. Summary of the Invention

[0004] This invention addresses the technical problem of the inability to precisely control the temperature and humidity of the gas fed into hydrogen fuel cells in the prior art.

[0005] This invention provides a method for controlling the temperature and humidity of hydrogen gas, comprising:

[0006] S1, obtain the flow rate of hydrogen gas entering the reactor, calculate the required flow rate of humidifying water based on the humidity of the hydrogen gas entering the reactor, and calculate the required temperature of the plate heat exchanger based on the temperature of the hydrogen gas entering the reactor.

[0007] S2, after mixing and humidifying the hydrogen with the required flow rate of humidifying water, it is then fed into the high-temperature intercooler for evaporation;

[0008] S3, control the temperature of the plate heater according to the required temperature to adjust the temperature of the evaporated mixed gas before it is put into the pile.

[0009] Preferably, before step S1, the method further includes: calculating the parameter values ​​of the current feed gas using formulas (1) to (3);

[0010] H = Mw / Ma (1)

[0011] Ф = H / ч * 100% (2)

[0012] G1 = Mw + Ma (3)

[0013] Where H is the current absolute humidity, Mw is the current water vapor mass, Ma is the current dry air mass, Ф is the current relative humidity, ч is the saturated humidity, and G1 is the measured current gas mass flow rate; the current Mw and Ma are calculated using the above formula.

[0014] Preferably, in step S1, the flow rate of the hydrogen gas entering the reactor is obtained, and the required flow rate of the humidifying water is calculated based on the required humidity of the hydrogen gas entering the reactor. Specifically, this includes:

[0015] First, based on the relative humidity Ф' of the required final gas to be fed into the reactor and the already calculated Ma, substitute them into the above formula to calculate the required total mass of water vapor Mw';

[0016] Then, calculate the required amount of liquid water M to be replenished. 补 = Mw' – Mw.

[0017] Preferably, in step S1, the flow rate of hydrogen entering the reactor is obtained, and the required temperature of the plate heat exchanger is calculated based on the required temperature of the hydrogen entering the reactor. Specifically, this includes:

[0018] The enthalpy of wet hydrogen gas at this time is calculated using the empirical formula: h1 = Cg*t + d(2501 + 1.86t) (4)

[0019] In equation (4), h1 is the enthalpy of wet hydrogen, t is the temperature of the mixed gas, Cg is the specific heat capacity of hydrogen, and d is the mass fraction parameter.

[0020] Where d can be calculated from Mw and Ma, as shown in formula (5):

[0021] d / (1+d)=Mw / (Mw+Ma) (5)

[0022] Similarly, the required enthalpy of wet hydrogen gas h2 and the required amount of humidifying water Mw2 can be calculated, and the enthalpy of the humidifying water h3 can be calculated as follows:

[0023] Since the mass of hydrogen Ma, the mass of water vapor Mw' and the required final temperature of the gas to be fed into the reactor have been known, the total enthalpy of the gas to be fed into the reactor can be calculated by substituting them into formulas (4) and (5);

[0024] Calculate the enthalpy of the replenished liquid water using the following formula: h3 = C×t 补 ×M 补 Where C is the specific heat capacity of liquid water obtained from a table, tcompensation is the temperature of the replenished liquid water (a known quantity), and Mreplenish is the temperature of the replenished liquid water. 补 The required amount of liquid water to be replenished has been determined.

[0025] The required heat to be added to the system is calculated as Q = h2 - h1 - h3;

[0026] Determine the temperature and flow rate of the plate heat exchanger based on the heat transfer formula:

[0027] Q=F×k×K×ΔTm

[0028] Q represents the total heat exchange, k is the fouling factor, K is the heat transfer coefficient, and ΔTm is the logarithmic mean temperature difference. k is linearly related to the plate heat exchanger temperature and flow rate, and is determined according to different plate heat exchangers.

[0029] Preferably, S2 specifically includes:

[0030] Hydrogen gas is mixed with the required flow rate of humidifying water and humidified at the humidification connector. The humidification connector adopts a Laval nozzle structure design. High-speed hydrogen gas is accelerated again through the Laval nozzle and comes into full contact with the liquid water introduced at the diffuser nozzle, producing liquid water atomization and diffusion, thus humidifying the incoming hydrogen gas.

[0031] Preferably, the water inlet pipe of the humidification connector is threaded to the hydrogen inlet pipe and sealed with a gasket. An annular humidification water passage is left at the connection to allow for a larger contact area between the humidification water and the hydrogen, so that the humidification water can be fully evaporated into water vapor.

[0032] This invention also provides a hydrogen temperature and humidity controllable testing system, the system being used to implement a hydrogen temperature and humidity controllable testing method, comprising:

[0033] The temperature and humidity calculation module is configured to obtain the flow rate of hydrogen entering the reactor, calculate the required flow rate of humidifying water based on the humidity of the hydrogen entering the reactor, and calculate the required temperature of the plate heat exchanger based on the temperature of the hydrogen entering the reactor.

[0034] The gas-water mixing module is configured to mix and humidify hydrogen with the required flow rate of humidifying water before feeding it into the high-temperature intercooler for evaporation.

[0035] The temperature control module is configured to control the temperature of the plate heater according to the required temperature, so as to adjust the temperature of the evaporated mixed gas before it is fed into the pile.

[0036] Beneficial Effects: This invention provides a controllable hydrogen temperature and humidity testing method and system. The method includes: obtaining the hydrogen flow rate into the fuel cell; calculating the required flow rate of humidifying water based on the required humidity of the hydrogen; and calculating the required temperature of the plate heat exchanger based on the required temperature of the hydrogen. The hydrogen is mixed with the required flow rate of humidifying water for humidification, and then fed into a high-temperature intercooler for evaporation. The temperature of the plate heater is controlled according to the required temperature to adjust the temperature of the evaporated mixture before it is fed into the fuel cell. This invention can effectively control the temperature and humidity of the fuel cell hydrogen circuit subsystem, which is helpful for fuel cell system performance research. Attached Figure Description

[0037] Figure 1 A schematic diagram of a controllable hydrogen temperature and humidity testing method provided by the present invention;

[0038] Figure 2 This is a schematic diagram of the humidification connector structure provided by the present invention.

[0039] Explanation of reference numerals in the attached diagram: Water inlet pipe 1, hydrogen inlet pipe 2, hydrogen outlet pipe 3. Detailed Implementation

[0040] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0041] Figure 1 The present invention provides a method for controlling the temperature and humidity of hydrogen gas, comprising:

[0042] S1, obtain the flow rate of hydrogen gas entering the reactor, calculate the required flow rate of humidifying water based on the humidity of the hydrogen gas entering the reactor, and calculate the required temperature of the plate heat exchanger based on the temperature of the hydrogen gas entering the reactor.

[0043] S2, after mixing and humidifying the hydrogen with the required flow rate of humidifying water, it is then fed into the high-temperature intercooler for evaporation;

[0044] S3, control the temperature of the plate heater according to the required temperature to adjust the temperature of the evaporated mixed gas before it is put into the pile.

[0045] The specific calculation process is as follows:

[0046] The parameter values ​​of the current feed gas are calculated using formulas (1) to (3);

[0047] H = Mw / Ma (1)

[0048] Ф = H / ч * 100% (2)

[0049] G1 = Mw + Ma (3)

[0050] Where H is the current absolute humidity, Mw is the current water vapor mass, Ma is the current dry air mass, Ф is the current relative humidity, ч is the saturated humidity, and G1 is the measured current gas mass flow rate; the current Mw and Ma are calculated using the above formula.

[0051] Calculate the required flow rate of the humidifying water, i.e., the amount of liquid water to be added, specifically including:

[0052] First, based on the relative humidity Ф' of the required final gas to be fed into the reactor and the already calculated Ma, substitute them into the above formula to calculate the required total mass of water vapor Mw';

[0053] Then, calculate the required amount of liquid water M to be replenished. 补 = Mw' – Mw.

[0054] Calculate the amount of heat that needs to be added to the system:

[0055] The enthalpy of wet hydrogen gas at this time is calculated using the empirical formula: h1 = Cg*t + d(2501 + 1.86t) (4)

[0056] In equation (4), h1 is the enthalpy of wet hydrogen, t is the temperature of the mixed gas, Cg is the specific heat capacity of hydrogen, and d is the mass fraction parameter.

[0057] Where d can be calculated from Mw and Ma, as shown in formula (5):

[0058] d / (1+d)=Mw / (Mw+Ma) (5)

[0059] Similarly, the required enthalpy of wet hydrogen gas h2 and the required amount of humidifying water Mw2 can be calculated, and the enthalpy of the humidifying water h3 can be calculated as follows:

[0060] Since the mass of hydrogen Ma, the mass of water vapor Mw' and the required final temperature of the gas to be fed into the reactor have been known, the total enthalpy of the gas to be fed into the reactor can be calculated by substituting them into formulas (4) and (5);

[0061] Calculate the enthalpy of the replenished liquid water using the following formula: h3 = C×t 补 ×M 补 Where C is the specific heat capacity of liquid water obtained from a table, tcompensation is the temperature of the replenished liquid water (a known quantity), and Mreplenish is the temperature of the replenished liquid water. 补 The required amount of liquid water to be replenished has been determined.

[0062] The required heat to be added to the system is calculated as Q = h2 - h1 - h3 = F × k × K × ΔTm;

[0063] Q represents the total heat exchange, k is the fouling factor, K is the heat transfer coefficient, and ΔTm is the logarithmic mean temperature difference. k is linearly related to the plate heat exchanger temperature and flow rate, and is determined according to different plate heat exchangers.

[0064] In a specific implementation scenario, S2 specifically includes:

[0065] Hydrogen gas is mixed with the required flow rate of humidifying water and humidified at the humidification joint. The humidification joint adopts a Laval nozzle structure design. High-speed hydrogen gas is accelerated again through the Laval nozzle and comes into full contact with the liquid water introduced at the diffuser nozzle, producing liquid water atomization and diffusion, which humidifies the incoming hydrogen gas. Then it is passed into the high-temperature intercooler, which allows the atomized liquid water to fully evaporate. Finally, the temperature of the gas entering the reactor is precisely controlled by a plate heat exchanger.

[0066] like Figure 2 As shown, the humidification connector includes: a water inlet pipe 1, a hydrogen inlet pipe 2, and a hydrogen outlet pipe 3. The water inlet pipe 1 and the hydrogen inlet pipe 2 are connected by threads and sealed with a sealing ring. External hydrogen enters the humidification connector after being controlled by an ejector and solenoid valves 1 and 2. The water inlet pipe 1 and the hydrogen inlet pipe 2 are connected by threads and sealed with a gasket. An annular humidification water passage is left at the connection point to maximize the contact area between the humidification water and hydrogen, allowing the humidification water to fully evaporate into water vapor. After mixing, the vapor is discharged through the hydrogen outlet pipe 3 to the intercooler, plate heat exchanger, and finally into the reactor.

[0067] This invention also provides a hydrogen temperature and humidity controllable testing system, the system being used to implement the above-mentioned hydrogen temperature and humidity controllable testing method, including:

[0068] The temperature and humidity calculation module is configured to obtain the flow rate of hydrogen entering the reactor, calculate the required flow rate of humidifying water based on the humidity of the hydrogen entering the reactor, and calculate the required temperature of the plate heat exchanger based on the temperature of the hydrogen entering the reactor.

[0069] The gas-water mixing module is configured to mix and humidify hydrogen with the required flow rate of humidifying water before feeding it into the high-temperature intercooler for evaporation.

[0070] The temperature control module is configured to control the temperature of the plate heater according to the required temperature, so as to adjust the temperature of the evaporated mixed gas before it is fed into the pile.

[0071] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0072] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A method for controlling the temperature and humidity of hydrogen gas, characterized in that, include: S1, obtain the flow rate of hydrogen entering the stack, calculate the required flow rate of humidifying water based on the humidity of the hydrogen entering the stack, and calculate the required temperature of the plate heat exchanger based on the temperature of the hydrogen entering the stack, and then convert the temperature into heat. S2, after mixing and humidifying the hydrogen with the required flow rate of humidifying water, it is then fed into the high-temperature intercooler for evaporation; S3, control the temperature of the plate heater according to the required temperature to adjust the temperature of the evaporated mixed gas before it is put into the pile; Before S1, the process also includes: calculating the parameter values ​​of the current infeed gas using formulas (1) to (3); H = Mw / Ma (1) Ф = H / ч * 100% (2) G1 = Mw + Ma (3) Where H is the current absolute humidity, Mw is the current water vapor mass, Ma is the current air mass, Ф is the current relative humidity, ч is the saturated humidity, and G1 is the measured current gas mass flow rate; the current Mw and Ma are calculated using the above formula.

2. The hydrogen temperature and humidity controllable testing method according to claim 1, characterized in that, In step S1, the flow rate of the hydrogen gas entering the reactor is obtained, and the required flow rate of the humidifying water is calculated based on the required humidity of the hydrogen gas entering the reactor. Specifically, this includes: First, based on the relative humidity Ф' of the required final gas to be fed into the reactor and the already calculated Ma, substitute them into the above formula to calculate the required total mass of water vapor Mw'; Then, calculate the required amount of liquid water M to be replenished. 补 = Mw' – Mw.

3. The hydrogen temperature and humidity controllable testing method according to claim 2, characterized in that, In step S1, the flow rate of hydrogen entering the reactor is obtained, and the required temperature of the plate heat exchanger is calculated based on the required temperature of the hydrogen entering the reactor. The temperature is then converted into heat, specifically including: The enthalpy of wet hydrogen gas at this time is calculated using the empirical formula: h1 = Cg*t + d(2501 + 1.86t) (4) In equation (4), h1 is the enthalpy of wet hydrogen, t is the temperature of the mixed gas, Cg is the specific heat capacity of hydrogen, and d is the mass fraction parameter. Where d can be calculated from Mw and Ma, as shown in formula (5): d / (1+d)=Mw / (Mw+Ma) (5) Similarly, the required enthalpy of wet hydrogen gas h2 and the required amount of humidifying water Mw2 can be calculated, and the enthalpy of the humidifying water h3 can be calculated as follows: Since the current air mass Ma, water vapor mass Mw' and the required final gas temperature t' at the time of injection are known, the total enthalpy h2 of the gas can be calculated by substituting them into formulas (4) and (5); Calculate the enthalpy of the replenished liquid water using the following formula: h3 = C×t 补 ×M 补 Where C is the specific heat capacity of liquid water obtained from a table, tcompensation is the temperature of the replenished liquid water (a known quantity), and Mreplenish is the temperature of the replenished liquid water. 补 The required amount of liquid water to be replenished has been determined. The required heat to be added to the system is calculated as Q = h2 - h1 - h3 = F × k × K × ΔTm; Q represents the total heat exchange, k is the fouling factor, K is the heat transfer coefficient, and ΔTm is the logarithmic mean temperature difference. k is linearly related to the plate heat exchanger temperature and flow rate, and is determined according to different plate heat exchangers.

4. The hydrogen temperature and humidity controllable testing method according to claim 1, characterized in that, S2 specifically includes: Hydrogen gas is mixed with the required flow rate of humidifying water and humidified at the humidification connector. The humidification connector adopts a Laval nozzle structure design. High-speed hydrogen gas is accelerated again through the Laval nozzle and comes into full contact with the liquid water introduced at the diffuser nozzle, producing liquid water atomization and diffusion, thus humidifying the incoming hydrogen gas.

5. The hydrogen temperature and humidity controllable testing method according to claim 4, characterized in that, The water inlet pipe of the humidification connector is connected to the hydrogen inlet pipe by threads and sealed with a gasket. An annular humidification water passage is left at the connection to allow for a larger contact area between the humidification water and the hydrogen, so that the humidification water can be fully evaporated into water vapor.

6. A hydrogen temperature and humidity controllable testing system, characterized in that, The system is used to implement the hydrogen temperature and humidity controllable testing method as described in any one of claims 1-5, including: The temperature and humidity calculation module is configured to obtain the flow rate of hydrogen entering the reactor, calculate the required flow rate of humidifying water based on the humidity of the hydrogen entering the reactor, and calculate the required temperature of the plate heat exchanger based on the temperature of the hydrogen entering the reactor. The gas-water mixing module is configured to mix and humidify hydrogen with the required flow rate of humidifying water before feeding it into the high-temperature intercooler for evaporation. The temperature control module is configured to control the temperature of the plate heater according to the required temperature, so as to adjust the temperature of the evaporated mixed gas before it is fed into the pile.

Images