SCR catalyst NH3 storage test method, system and equipment and storage medium

Abstract

The invention discloses an SCR catalyst NH3 storage test method, system and equipment and a storage medium, belongs to the technical field of tail gas after-treatment, and solves the technical problem of inaccurate SCR catalyst NH3 storage test. The method comprises the following steps: carrying out NH3 adsorption and desorption tests by mounting the SCR catalytic unit on a test bed; one flow, M different inlet NH3 concentrations and N different adsorption temperatures are set, and M * N test conditions are provided; maintaining the temperature of the gas at the inlet of the catalytic unit at the adsorption temperature of the specified test working condition, and introducing a mixed gas of NH3 gas with the NH3 concentration at the inlet of the specified test working condition and background gas into the catalytic unit; after adsorption saturation, ammonia is required to be desorbed; recording a change process curve of the NH3 concentration at the input end of the catalytic unit and a change process curve of the NH3 concentration at the output end of the catalytic unit; and calculating the NH3 storage amount of the catalytic unit under various test working conditions through integration. The NH3 storage capacity is directly measured, the testing precision is high, and rack resources can be saved.

Description

Technical Field

[0001] The present invention relates to the technical field of exhaust gas post-treatment, and more specifically, to a SCR catalyst NH3 storage test method, system, equipment and storage medium. Background Art

[0002] In the diesel engine exhaust after-treatment system, the SCR catalytic unit is responsible for purifying the engine's harmful emissions, NOx. The SCR catalytic unit is coated with an SCR catalyst, which has the function of adsorbing and storing NH3. NOx in the engine exhaust reacts with NH3 on the catalyst surface to produce N2 and H2O, thereby achieving the purpose of removing NOx. The ASC catalytic unit is generally located downstream of the SCR catalytic unit. Its main function is to remove the remaining NH3 through an oxidation reaction to prevent NH3 from being discharged into the atmosphere. The ASC catalytic unit is generally also coated with a certain SCR catalyst, so it also has the function of adsorbing and utilizing NH3 to remove NOx.

[0003] The NH3 storage of the SCR catalyst has a key impact on the NOx conversion efficiency of the SCR and ASC catalytic units. The quantification of NH3 storage in the catalytic unit plays a vital role in the evaluation of the performance of the after-treatment system, the construction and calibration of the simulation model of the after-treatment system, and the system development work.

[0004] Patent application document CN201911305016.2 discloses a SCR catalyst NH3 storage test method, and proposes an SCR catalyst NH3 storage test method based on a single-point engine test condition. However, when conducting actual engine operating condition tests, the boundary conditions of the post-treatment system are difficult to control, and multiple chemical reactions occur simultaneously in the SCR and ASC catalytic units, which will affect the quantification of SCR catalyst NH3 storage, thereby affecting the test accuracy. In addition, the actual engine operating condition test will consume a large amount of bench resources including fuel, urea aqueous solution, etc. Summary of the invention

[0005] The technical problem to be solved by the present invention is to address the above-mentioned deficiencies in the prior art. The first object of the present invention is to provide an SCR catalyst NH3 adsorption and desorption test method and an NH3 storage calculation method, which can ensure the test accuracy.

[0006] A second objective of the present invention is to provide an SCR catalyst NH3 storage test system.

[0007] A third object of the present invention is to provide a computer device.

[0008] A fourth objective of the present invention is to provide a computer storage medium.

[0009] In order to achieve the above-mentioned first objective, the present invention provides a method for testing NH3 storage of an SCR catalyst, which comprises the following steps: installing a catalytic unit on a small sample test bench to perform NH3 adsorption and desorption tests, and calculating NH3 storage based on the test results;

[0010] Step 1. Set the test conditions, including setting 1 gas flow rate, M different inlet NH3 concentration target values ​​C_nh3_ads(i), and setting N different adsorption temperature target values ​​T_ads(j), where 1≤i≤M, 1≤j≤N, a total of M×N test conditions;

[0011] Step 2. Under the gas flow rate, background gas is introduced into the catalytic unit, and the measured temperature T_in(j) of the inlet gas of the catalytic unit is adjusted to increase and stably maintain at T_ads(j);

[0012] Step 3. A mixture of NH3 gas and background gas is introduced into the catalytic unit, so that the measured concentration C_nh3_in(i) of the NH3 gas at the inlet of the catalytic unit quickly reaches and stabilizes at C_nh3_ads(i);

[0013] When the measured concentration of NH3 gas at the outlet of the catalytic unit C_nh3_out(i) rises to C_nh3_ads(i) and reaches a stable state, the introduction of NH3 gas is stopped after maintaining the stable state for t1 time;

[0014] Step 4. Continue to introduce the background gas into the catalytic unit until the measured concentration C_nh3_out(i) of the NH3 gas at the outlet of the catalytic unit decreases and reaches a stable state;

[0015] Step 5. The measured inlet gas temperature T_in(j) of the catalytic unit is uniformly increased to the maximum temperature T_max and maintained until the measured outlet NH3 gas concentration C_nh3_out(i) of the catalytic unit first increases and then decreases and reaches a stable state. After maintaining the stable state for t2 time, the test of the (i, j) operating point is completed;

[0016] From step 1 to step 5, the measured inlet gas temperature T_in(j), the measured inlet NH3 gas concentration C_nh3_in(i), and the measured outlet NH3 gas concentration C_nh3_out(i) of the catalytic unit are obtained in real time, and their change process curves are recorded;

[0017] Step 6. Calculate the NH3 storage capacity of the catalytic unit by integration according to the change history curve of the measured concentration of NH3 gas at the inlet C_nh3_in(i) and the measured concentration of NH3 gas at the outlet C_nh3_out(i) of the catalytic unit;

[0018] Step 7. Based on the NH3 storage capacity of the catalytic unit and the carrier parameters of the catalytic unit, the NH3 storage capacity can be converted into NH3 storage capacity related data required for modeling the after-treatment system;

[0019] According to steps 2 to 7, complete the test of all M×N test conditions under the gas flow rate and the calculation of NH3 storage capacity related data.

[0020] As a further improvement, the catalytic unit is installed in a quartz tube of a small sample test bench, the gas flow rate is calculated according to the air velocity and the volume of the catalytic unit, the gas flow rate needs to be lower than the rated flow rate of the small sample test bench, and the air velocity can be set according to the common air velocity of the SCR unit of the diesel engine aftertreatment system;

[0021] The number of the catalytic unit is 1, and the shape is cylindrical, and the diameter and length of the catalytic unit must meet the installation requirements of the catalytic unit inside the quartz tube.

[0022] Furthermore, said M is not less than 2;

[0023] The inlet NH3 concentration target value C_nh3_ads(i) is not less than 100 ppm;

[0024] The N is not less than 3;

[0025] The adsorption temperature target value T_ads(j) is not less than 100°C;

[0026] The background gas is a mixture of H2O and N2, wherein the H2O concentration can be set according to the common water concentration in diesel engine exhaust, and N2 is the filling gas.

[0027] Furthermore, the t1 time is greater than 3 minutes;

[0028] The t2 time is greater than 3 minutes;

[0029] The maximum temperature T_max is higher than 450°C and lower than 500°C.

[0030] Furthermore, by setting NH3 concentration measurement points at the input end and the output end of the catalytic unit respectively, the measured concentration C_nh3_in(i) of the inlet NH3 gas and the measured concentration C_nh3_out(i) of the outlet NH3 gas of the catalytic unit are obtained in real time;

[0031] By setting a temperature measuring point at the input end of the catalytic unit, the actual measured temperature T_in(j) of the inlet gas of the catalytic unit is obtained in real time;

[0032] The distance between the input and output NH3 concentration measuring points and the input temperature measuring point and the catalytic unit must be controlled within 3 cm.

[0033] Furthermore, when there is only one gas analyzer for measuring NH3 concentration, the gas analyzer cannot be connected to two NH3 measurement points at the same time. In this case, two tests can be carried out under the same test conditions;

[0034] During the first test, the gas analyzer is connected to the NH3 measuring point at the output end to record the complete change history of the measured NH3 gas concentration C_nh3_out(i) at the outlet of the catalytic unit, and to record the time of the NH3 gas ventilation and gas stop at the input end;

[0035] During the second test, the gas analyzer is connected to the NH3 measuring point at the input end to record the rise and fall of the measured concentration C_nh3_in(i) of the inlet NH3 gas of the catalytic unit during the ventilation and gas stop processes;

[0036] By combining the two sets of data obtained from the two tests, the change history curves of the measured concentration of NH3 gas at the inlet C_nh3_in(i) and the measured concentration of NH3 gas at the outlet C_nh3_out(i) of the catalytic unit can be obtained.

[0037] Furthermore, the quartz tube is located in the inner cavity of the heating furnace, a heating tube is installed inside the heating furnace, and the heating tube is located outside the quartz tube. The heating furnace heats the catalytic unit and its inlet gas.

[0038] In order to achieve the above-mentioned second objective, the present invention provides an SCR catalyst NH3 storage test system, comprising:

[0039] Small sample test bench, used to install the catalytic unit on the test bench to conduct NH3 storage adsorption process and desorption process tests;

[0040] The working condition setting module is used to set the test working conditions, including setting 1 gas flow rate, M different inlet NH3 concentration target values ​​C_nh3_ads(i), and setting N different adsorption temperature target values ​​T_ads(j), where 1≤i≤M, 1≤j≤N, and a total of M×N test working conditions;

[0041] A test module, used for introducing background gas into the catalytic unit at the gas flow rate, and adjusting the measured temperature T_in(j) of the inlet gas of the catalytic unit to increase and stably maintain it at T_ads(j);

[0042] A mixture of NH3 gas and background gas is introduced into the catalytic unit, so that the measured concentration C_nh3_in(i) of NH3 gas at the inlet of the catalytic unit quickly reaches and stabilizes at C_nh3_ads(i);

[0043] When the measured concentration of NH3 gas at the outlet of the catalytic unit C_nh3_out(i) rises to C_nh3_ads(i) and reaches a stable state, the introduction of NH3 gas is stopped after maintaining the stable state for t1 time;

[0044] Continue to introduce the background gas into the catalytic unit until the measured concentration C_nh3_out(i) of the NH3 gas at the outlet of the catalytic unit decreases and reaches a stable state;

[0045] The measured inlet gas temperature T_in(j) of the catalytic unit is uniformly increased to the maximum temperature T_max and maintained until the measured outlet NH3 gas concentration C_nh3_out(i) of the catalytic unit first increases and then decreases and reaches a stable state. After maintaining the stable state for t2 time, the test of the (i, j) operating point is completed;

[0046] Obtain the measured inlet gas temperature T_in(j), the measured inlet NH3 gas concentration C_nh3_in(i), and the measured outlet NH3 gas concentration C_nh3_out(i) of the catalytic unit in real time, and record their change history curves;

[0047] A calculation module, used to calculate the NH3 storage capacity of the catalytic unit by integration according to the change history curve of the measured NH3 gas concentration C_nh3_in(i) at the inlet of the catalytic unit and the measured NH3 gas concentration C_nh3_out(i) at the outlet; until the test of all M×N test conditions and the calculation of NH3 storage capacity related data are completed;

[0048] Based on the NH3 storage amount of the catalytic unit and the carrier parameters of the catalytic unit, the NH3 storage amount can be converted into NH3 storage amount related data required for modeling of the after-treatment system.

[0049] In order to achieve the third objective above, the present invention provides a computer device, including a memory and a processor, wherein the memory stores a computer program, and the processor implements the above-mentioned SCR catalyst NH3 storage test method when executing the computer program.

[0050] In order to achieve the fourth objective above, the present invention provides a computer-readable storage medium having a computer program stored thereon, and when the computer program is executed by a processor, the above-mentioned SCR catalyst NH3 storage test method is implemented.

[0051] Beneficial Effects

[0052] Compared with the prior art, the present invention has the following advantages:

[0053] Different from the traditional bench test, the present invention only uses the catalytic unit for the test, which can save a lot of bench resources including fuel, urea aqueous solution, etc. Moreover, the gas introduced into the test of the present invention does not contain NOx, which can avoid the quantitative impact on NH3 storage caused by chemical reaction with NOx, thereby ensuring the test accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 This is the test flow chart of this invention;

[0055] Figure 2 This is a schematic diagram of the test boundary condition control;

[0056] Figure 3 Schematic diagram of the catalytic unit installation.

[0057] Among them, 1-catalytic unit, 2-test bench, 3-NH3 measuring point, 4-temperature measuring point, 5-gas analyzer, 6-quartz tube, 7-heating furnace, 8-heating tube. DETAILED DESCRIPTION

[0058] The present invention will be further described below with reference to the specific embodiments in the accompanying drawings.

[0059] See also Figure 1 to Figure 3 , a SCR catalyst NH3 storage test method, by installing a catalyst unit 1 on a small sample test bench 2 to perform NH3 adsorption and desorption tests, and calculating NH3 storage based on the test results. The catalyst unit 1 can be the entire SCR post-processor, or a unit in the SCR post-processor, or a test model that is proportionally reduced according to the SCR post-processor.

[0060] The test includes the following steps 1 to 7:

[0061] Step 1. Set the test conditions, including setting 1 gas flow rate, M different inlet NH3 concentration target values ​​C_nh3_ads(i), and setting N different adsorption temperature target values ​​T_ads(j), where 1≤i≤M, 1≤j≤N, for a total of M×N test conditions.

[0062] Step 2. Under the gas flow rate, the background gas is introduced into the catalyst unit 1, and the measured temperature T_in(j) of the inlet gas of the catalyst unit 1 is adjusted to increase and stably maintain at T_ads(j). Figure 2During the time when the blue square wave and the red line intersect horizontally, the blue square wave represents the inlet NH3 concentration, i.e., the inlet NH3 concentration target value C_nh3_ads(i), and the horizontal segment of the red line represents the adsorption temperature, i.e., the adsorption temperature target value T_ads(j). The background gas can be N2 or N2 and water vapor.

[0063] Step 3. A mixture of NH3 gas and background gas is introduced into the catalytic unit 1, so that the measured concentration C_nh3_in(i) of the NH3 gas at the inlet of the catalytic unit 1 quickly reaches and stabilizes at C_nh3_ads(i).

[0064] When the measured concentration C_nh3_out(i) of the NH3 gas at the outlet of the catalytic unit 1 rises to C_nh3_ads(i) and reaches a stable state, the introduction of NH3 gas is stopped after the stable state is maintained for t1 time.

[0065] Step 4. Continue to introduce background gas into the catalytic unit 1 until the measured concentration C_nh3_out(i) of NH3 gas at the outlet of the catalytic unit 1 decreases and reaches a stable state.

[0066] Step 5. The measured temperature T_in(j) of the inlet gas of the catalytic unit 1 is raised uniformly to the maximum temperature T_max and maintained, as follows: Figure 2 The red line in the middle is inclined, until the measured concentration of NH3 gas at the outlet of the catalytic unit 1 C_nh3_out(i) first rises and then falls and reaches a stable state. After maintaining the stable state for t2 time, the test of the (i, j) operating point is completed.

[0067] From step 1 to step 5, the measured inlet gas temperature T_in(j), the measured inlet NH3 gas concentration C_nh3_in(i), and the measured outlet NH3 gas concentration C_nh3_out(i) of the catalytic unit 1 are obtained in real time, and their change history curves are recorded.

[0068] Step 6. Calculate the NH3 storage capacity of the catalytic unit 1 by integration according to the change history curves of the measured NH3 gas concentration C_nh3_in(i) at the inlet and the measured NH3 gas concentration C_nh3_out(i) at the outlet of the catalytic unit 1.

[0069] Step 7. Based on the NH3 storage capacity of the catalyst unit 1 and the carrier parameters of the catalyst unit 1, the NH3 storage capacity can be converted into NH3 storage capacity related data required for post-treatment system modeling (since the sizes of various types of SCR post-processors are different, the NH3 storage capacity of the catalyst unit 1 needs to be converted).

[0070] Follow steps 2 to 7 to complete the test of all M×N test conditions under gas flow and the calculation of NH3 storage capacity related data.

[0071] Specifically, the catalytic unit 1 is installed in the quartz tube 6 of the small sample test bench 2. The gas flow rate is calculated based on the air velocity and the volume of the catalytic unit 1. The gas flow rate needs to be lower than the rated flow rate of the small sample test bench 2. The air velocity can be set according to the common air velocity of the SCR unit of the diesel engine aftertreatment system.

[0072] The number of the catalytic unit 1 is 1, and the shape is cylindrical, and the diameter and length thereof must meet the installation requirements of the catalytic unit 1 inside the quartz tube 6 .

[0073] M is not less than 2; the inlet NH3 concentration target value C_nh3_ads(i) is not less than 100ppm; N is not less than 3; the adsorption temperature target value T_ads(j) is not less than 100℃;

[0074] The background gas is a mixture of H2O and N2, wherein the H2O concentration can be set according to the common water concentration in diesel engine exhaust, and N2 is the filling gas.

[0075] The t1 time is greater than 3 minutes; the t2 time is greater than 3 minutes; the maximum temperature T_max is higher than 450°C and lower than 500°C.

[0076] In this embodiment, the inlet NH3 gas actual measured concentration C_nh3_in(i) and the outlet NH3 gas actual measured concentration C_nh3_out(i) of the catalytic unit 1 can be obtained in real time by setting NH3 concentration measurement points 3 at the input and output ends of the catalytic unit 1 respectively.

[0077] By setting a temperature measuring point 4 at the input end of the catalytic unit 1 , the actual measured temperature T_in(j) of the inlet gas of the catalytic unit 1 can be obtained in real time.

[0078] The distance between the NH3 concentration measuring point 3 at the input and output ends and the temperature measuring point 4 at the input end and the catalytic unit 1 must be controlled within 3 cm.

[0079] Generally, a gas analyzer is used to test the NH3 concentration. The gas analyzer is expensive, and most experiments are equipped with only one gas analyzer. When there is only one gas analyzer 5 for measuring the NH3 concentration, the gas analyzer 5 cannot be connected to two NH3 measuring points 3 at the same time. In this case, two tests can be carried out under the same test conditions.

[0080] During the first test, the gas analyzer 5 is connected to the NH3 measuring point 3 at the output end to record the change history of the measured NH3 gas concentration C_nh3_out(i) at the outlet of the complete catalytic unit 1 and the time of the NH3 gas ventilation and shut-off at the input end.

[0081] During the second test, the gas analyzer 5 is connected to the NH3 measuring point 3 at the input end to record the rising and falling process of the measured concentration C_nh3_in(i) of the inlet NH3 gas of the catalytic unit 1 during the ventilation and gas-off processes.

[0082] By combining the two sets of data obtained from the two tests, the change history curves of the measured concentration of NH3 gas at the inlet C_nh3_in(i) and the measured concentration of NH3 gas at the outlet C_nh3_out(i) of the catalytic unit 1 can be obtained.

[0083] The quartz tube 6 is located in the inner cavity of the heating furnace 7. A heating tube 8 is installed inside the heating furnace 7. The heating tube 7 is located outside the quartz tube 6. The heating furnace 7 heats the catalytic unit 1 and its inlet gas.

[0084] An SCR catalyst NH3 storage test system, comprising:

[0085] A small sample test bench 2, used to install the catalytic unit 1 on the test bench 2 to conduct NH3 storage adsorption process and desorption process tests;

[0086] The working condition setting module is used to set the test working conditions, including setting 1 gas flow rate, M different inlet NH3 concentration target values ​​C_nh3_ads(i), and setting N different adsorption temperature target values ​​T_ads(j), where 1≤i≤M, 1≤j≤N, and a total of M×N test working conditions;

[0087] The test module is used to introduce background gas into the catalytic unit 1 under the gas flow rate, and adjust the measured temperature T_in(j) of the inlet gas of the catalytic unit 1 to increase and stably maintain it at T_ads(j);

[0088] A mixture of NH3 gas and background gas is introduced into the catalyst unit 1, so that the measured concentration C_nh3_in(i) of the NH3 gas at the inlet of the catalyst unit 1 quickly reaches and stabilizes at C_nh3_ads(i);

[0089] When the measured concentration of NH3 gas at the outlet of the catalytic unit 1 C_nh3_out(i) rises to C_nh3_ads(i) and reaches a stable state, the introduction of NH3 gas is stopped after maintaining the stable state for t1 time;

[0090] Continue to introduce background gas into the catalyst unit 1 until the measured concentration C_nh3_out(i) of NH3 gas at the outlet of the catalyst unit 1 decreases and reaches a stable state;

[0091] The measured inlet gas temperature T_in(j) of the catalytic unit 1 is uniformly increased to the maximum temperature T_max and maintained until the measured outlet NH3 gas concentration C_nh3_out(i) of the catalytic unit 1 first increases and then decreases and reaches a stable state. After maintaining the stable state for t2 time, the test of the (i, j) operating point is completed;

[0092] Obtain the measured inlet gas temperature T_in(j), the measured inlet NH3 gas concentration C_nh3_in(i), and the measured outlet NH3 gas concentration C_nh3_out(i) of the catalytic unit 1 in real time, and record their change history curves;

[0093] A calculation module is used to calculate the NH3 storage capacity of the catalytic unit 1 by integration according to the change history curve of the measured NH3 gas concentration C_nh3_in(i) at the inlet of the catalytic unit 1 and the measured NH3 gas concentration C_nh3_out(i) at the outlet; until the test of all M×N test conditions and the calculation of NH3 storage capacity related data are completed;

[0094] Based on the NH3 storage amount of the catalytic unit 1 and the carrier parameters of the catalytic unit 1 , the NH3 storage amount can be converted into NH3 storage amount related data required for modeling the after-treatment system.

[0095] A computer device includes a memory and a processor. The memory stores a computer program. When the processor executes the computer program, the above-mentioned SCR catalyst NH3 storage test method is implemented.

[0096] A computer-readable storage medium stores a computer program, which implements the above-mentioned SCR catalyst NH3 storage test method when executed by a processor.

[0097] The above are only preferred embodiments of the present invention. It should be pointed out that for those skilled in the art, several modifications and improvements can be made without departing from the structure of the present invention, which will not affect the effect of the implementation of the present invention and the practicality of the patent.

Claims

1. A method for testing the storage of NH3 in an SCR catalyst, characterized in that: The method comprises the following steps: installing a catalyst unit (1) on a small-scale test bench (2) to perform an NH3 adsorption and desorption test, and calculating the NH3 storage based on the test results; Step 1. Set the test conditions, including setting 1 gas flow rate, M different inlet NH3 concentration target values ​​C_nh3_ads(i), and setting N different adsorption temperature target values ​​T_ads(j), where 1≤i≤M, 1≤j≤N, a total of M×N test conditions; Step 2. Under the gas flow rate, background gas is introduced into the catalyst unit (1), and the measured temperature T_in(j) of the inlet gas of the catalyst unit (1) is adjusted to increase and stably maintain at T_ads(j); Step 3. A mixture of NH3 gas and background gas is introduced into the catalytic unit (1), so that the measured concentration C_nh3_in(i) of the NH3 gas at the inlet of the catalytic unit (1) quickly reaches and stabilizes at C_nh3_ads(i); When the measured concentration C_nh3_out(i) of the NH3 gas at the outlet of the catalytic unit (1) rises to C_nh3_ads(i) and reaches a stable state, the introduction of NH3 gas is stopped after maintaining the stable state for t1 time; Step 4. Continue to introduce the background gas into the catalytic unit (1) until the measured concentration C_nh3_out(i) of the NH3 gas at the outlet of the catalytic unit (1) decreases and reaches a stable state; Step 5. The measured inlet gas temperature T_in(j) of the catalytic unit (1) is uniformly increased to the maximum temperature T_max and maintained until the measured outlet NH3 gas concentration C_nh3_out(i) of the catalytic unit (1) first increases and then decreases and reaches a stable state. After maintaining the stable state for t2 time, the test of the (i, j) operating point is completed; From step 1 to step 5, the measured inlet gas temperature T_in(j), the measured inlet NH3 gas concentration C_nh3_in(i), and the measured outlet NH3 gas concentration C_nh3_out(i) of the catalytic unit (1) are obtained in real time, and their change history curves are recorded; Step 6. Calculate the NH3 storage capacity of the catalytic unit (1) by integration according to the change history curves of the measured concentration of NH3 gas at the inlet C_nh3_in(i) and the measured concentration of NH3 gas at the outlet C_nh3_out(i) of the catalytic unit (1); Step 7. Based on the NH3 storage capacity of the catalyst unit (1) and the carrier parameters of the catalyst unit (1), the NH3 storage capacity can be converted into NH3 storage capacity related data required for post-treatment system modeling; According to steps 2 to 7, complete the test of all M×N test conditions under the gas flow rate and the calculation of NH3 storage capacity related data.

2. The SCR catalyst NH3 storage test method according to claim 1, characterized in that: The catalytic unit (1) is installed in a quartz tube (6) of a small sample test bench (2); the gas flow rate is calculated based on the air velocity and the volume of the catalytic unit (1); the gas flow rate needs to be lower than the rated flow rate of the small sample test bench (2); the air velocity can be set based on the common air velocity of the SCR unit of the diesel engine aftertreatment system; The number of the catalytic unit (1) is 1 and the shape is cylindrical, and the diameter and length thereof must meet the installation requirements of the catalytic unit (1) inside the quartz tube (6).

3. The SCR catalyst NH3 storage test method according to claim 1, characterized in that: The M is not less than 2; The inlet NH3 concentration target value C_nh3_ads(i) is not less than 100 ppm; The N is not less than 3; The adsorption temperature target value T_ads(j) is not less than 100°C; The background gas is a mixture of H2O and N2, wherein the H2O concentration can be set according to the common water concentration in diesel engine exhaust, and N2 is the filling gas.

4. The SCR catalyst NH3 storage test method according to claim 1, characterized in that: The t1 time is greater than 3 minutes; The t2 time is greater than 3 minutes; The maximum temperature T_max is higher than 450°C and lower than 500°C.

5. The SCR catalyst NH3 storage test method according to claim 1, characterized in that: By setting NH3 concentration measurement points (3) at the input end and the output end of the catalytic unit (1), respectively, the actual measured concentration C_nh3_in(i) of the inlet NH3 gas and the actual measured concentration C_nh3_out(i) of the outlet NH3 gas of the catalytic unit (1) are obtained in real time; By setting a temperature measuring point (4) at the input end of the catalytic unit (1), the actual measured temperature T_in(j) of the inlet gas of the catalytic unit (1) is obtained in real time; The distance between the input and output NH3 concentration measuring points (3) and the input temperature measuring point (4) and the catalytic unit (1) must be controlled within 3 cm.

6. The SCR catalyst NH3 storage test method according to claim 5, characterized in that: When there is only one gas analyzer (5) for measuring NH3 concentration, the gas analyzer (5) cannot be connected to two NH3 measuring points (3) at the same time. In this case, two tests can be carried out under the same test conditions. During the first test, the gas analyzer (5) is connected to the NH3 measuring point (3) at the output end, and is used to record the complete change history of the measured NH3 gas concentration C_nh3_out(i) at the outlet of the catalytic unit (1), and to record the time of the NH3 gas ventilation and gas cut-off at the input end; During the second test, the gas analyzer (5) is connected to the NH3 measuring point (3) at the input end to record the rising and falling process of the measured concentration C_nh3_in(i) of the inlet NH3 gas of the catalytic unit (1) during the ventilation and gas-off processes; By combining the two sets of data obtained from the two tests, the change history curves of the measured concentration of NH3 gas at the inlet C_nh3_in(i) and the measured concentration of NH3 gas at the outlet C_nh3_out(i) of the catalytic unit (1) can be obtained.

7. The SCR catalyst NH3 storage test method according to claim 2, characterized in that: The quartz tube (6) is located in the inner cavity of the heating furnace (7), a heating tube (8) is installed inside the heating furnace (7), and the heating tube (7) is located outside the quartz tube (6). The heating furnace (7) heats the catalytic unit (1) and its inlet gas.

8. An SCR catalyst NH3 storage test system, characterized in that: include: A small sample test bench (2), used for installing the catalytic unit (1) on the test bench (2) to carry out NH3 storage adsorption process and desorption process tests; The working condition setting module is used to set the test working conditions, including setting 1 gas flow rate, M different inlet NH3 concentration target values ​​C_nh3_ads(i), and setting N different adsorption temperature target values ​​T_ads(j), where 1≤i≤M, 1≤j≤N, and a total of M×N test working conditions; A test module, used for introducing background gas into the catalytic unit (1) at the gas flow rate, and adjusting the measured temperature T_in(j) of the inlet gas of the catalytic unit (1) to increase and stably maintain it at T_ads(j); A mixture of NH3 gas and background gas is introduced into the catalytic unit (1), so that the measured concentration C_nh3_in(i) of NH3 gas at the inlet of the catalytic unit (1) quickly reaches and stabilizes at C_nh3_ads(i); When the measured concentration C_nh3_out(i) of the NH3 gas at the outlet of the catalytic unit (1) rises to C_nh3_ads(i) and reaches a stable state, the introduction of NH3 gas is stopped after maintaining the stable state for t1 time; Continue to introduce the background gas into the catalytic unit (1) until the measured concentration C_nh3_out(i) of the NH3 gas at the outlet of the catalytic unit (1) decreases and reaches a stable state; The measured temperature T_in(j) of the inlet gas of the catalytic unit (1) is uniformly increased to the maximum temperature T_max and maintained until the measured concentration C_nh3_out(i) of the NH3 gas at the outlet of the catalytic unit (1) first increases and then decreases and reaches a stable state. After maintaining the stable state for t2 time, the test of the (i, j) operating point is completed; Real-time acquisition of the measured inlet gas temperature T_in(j), the measured inlet NH3 gas concentration C_nh3_in(i), and the measured outlet NH3 gas concentration C_nh3_out(i) of the catalytic unit (1), and recording their change history curves; A calculation module, used to calculate the NH3 storage capacity of the catalytic unit (1) by integration according to the change history curve of the measured NH3 gas concentration C_nh3_in(i) at the inlet and the measured NH3 gas concentration C_nh3_out(i) at the outlet of the catalytic unit (1); Until all the M×N test conditions are tested and the NH3 storage capacity related data are calculated; Based on the NH3 storage capacity of the catalytic unit (1) and the carrier parameters of the catalytic unit (1), the NH3 storage capacity can be converted into NH3 storage capacity related data required for post-treatment system modeling.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the SCR catalyst NH3 storage test method according to any one of claims 1 to 7 is implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, an SCR catalyst NH3 storage test method according to any one of claims 1 to 7 is implemented.

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