Device and method for evaluating adaptability of denitration catalyst for coal-fired flue gas under low-load operation

Abstract

The present invention provides a device and method for evaluating the adaptability of a coal-fired flue gas denitration catalyst to low-load operation, belonging to the field of flue gas denitration. The evaluation method includes: using the evaluation device to test the activity of the denitration catalyst before and after poisoning and after poisoning recovery, obtaining the initial activity, the first activity and the second activity of the catalyst; determining process characteristic indexes based on the initial activity, the first activity and the second activity; obtaining the measured values of the physical and chemical characteristics of the denitration catalyst before and after poisoning and after poisoning recovery, and determining physical and chemical characteristic indexes; measuring the conventional process indexes of the denitration catalyst under different working conditions; and evaluating the adaptability of the denitration catalyst to low-load operation based on the process characteristic indexes, the physical and chemical characteristic indexes and the conventional process indexes. Through the method provided by the present invention, the adaptability of this type of catalyst to low-load operation can be evaluated more accurately, making up for the deficiencies in the quality supervision and evaluation of the adaptability of the catalyst to low-load operation.

Description

Technical Field

[0001] The present invention relates to the technical field of flue gas denitrification in thermal power plants. Specifically, it relates to an evaluation device for the low-load operation adaptability of a coal-fired flue gas denitrification catalyst and an evaluation method for the low-load operation adaptability of a coal-fired flue gas denitrification catalyst. Background Art

[0002] As the core component of the SCR flue gas denitrification technology (Selective Catalytic Reduction, abbreviated as SCR, i.e., the selective catalytic reduction denitrification technology), the catalyst usually has clear requirements for the operating temperature range. However, under the current general trend of carbon emission reduction and new energy development in China, after the thermal power is connected to the grid power system, it needs to participate in the normalized deep peak shaving, resulting in the unit running at a low load for a long time. The traditional SCR denitrification catalyst cannot reach the necessary reaction activity and denitrification efficiency under the condition of low flue gas temperature, and at the same time, the ABS (i.e., ammonium bisulfate) generated in the low-temperature environment deposits on the catalyst surface, further leading to the rapid deactivation of the catalyst, resulting in the inability to guarantee the up-to-standard emission of nitrogen oxides.

[0003] At present, mainly through technologies such as boiler water mixing and temperature raising method, and economizer denitrification bypass, etc., to increase the SCR denitrification inlet flue gas temperature to meet the denitrification requirements during peak shaving, and these measures undoubtedly increase the additional energy consumption and capital investment of the power plant. In this situation, the denitrification catalyst technology emerged for the full-load flue gas denitrification operation in the thermal power field, but it also bred chaos in the catalyst industry. Analyzing the current denitrification catalyst industry and technology for thermal power plant flue gas, there are mainly the following problems:

[0004] 1) The method of increasing the flue gas temperature through bypass transformation has a long cycle, increases energy consumption, and increases the operation and maintenance cost;

[0005] 2) When operating under the condition of long-term low load, whether the catalyst can operate stably to ensure its reaction activity and denitrification efficiency, and ensure the up-to-standard emission of the outlet NO x concentration during deep peak shaving;

[0006] 3) Whether a large amount of ABS will deposit on the catalyst surface, resulting in the rapid deactivation of the catalyst;

[0007] 4) The performance index requirements for the low-load operation of the catalyst have not been clarified, and the inspection standard system has not been established, and it is impossible to carry out quality supervision and evaluation of this type of catalyst according to the current standards. Summary of the Invention

[0008] Aiming at the technical problem that the traditional denitrification catalyst detection device in the prior art cannot simulate the ABS poisoning experiment of the catalyst, the present invention provides an evaluation device for the low-load operation adaptability of a coal-fired flue gas denitrification catalyst. Using this device, the low-load operation adaptability of the denitrification catalyst can be evaluated more accurately.

[0009] To achieve the above object, a first aspect of the present invention provides an evaluation device for the low-load operation adaptability of a coal-fired flue gas denitration catalyst. The evaluation device includes a flue gas generation mechanism, an SCR catalytic reaction mechanism, and an SO3 generation mechanism; the flue gas generation mechanism is used to configure coal-fired flue gas according to the simulated flue gas volume and flue gas components; the SO3 generation mechanism is used to provide SO3; the SCR catalytic reaction mechanism is connected to the flue gas generation mechanism and is used to simulate the denitration reaction process of the denitration catalyst and the coal-fired flue gas; the SCR catalytic reaction mechanism is also connected to the SO3 generation mechanism and is used to simulate the denitration reaction process of the denitration catalyst poisoned by ABS and the coal-fired flue gas.

[0010] In an exemplary embodiment of the present invention, the evaluation device may further include an ABS cleaning mechanism, which is arranged in the connecting pipeline between the SCR catalytic reaction mechanism and the SO3 generation mechanism and is used to remove the blocked ABS in the connecting pipeline.

[0011] In an exemplary embodiment of the present invention, the flue gas generation mechanism may include an N2 gas tank, an air tank, a NO x gas cylinder, an SO2 gas cylinder, an NH3 gas cylinder, and a mixer. The N2 gas tank, the air tank, the NO x gas cylinder, the SO2 gas cylinder, and the NH3 gas cylinder are respectively connected to the mixer through inlet pipelines. The mixer is used to mix N2, air, NO x , SO2, and NH3 to form coal-fired flue gas.

[0012] In an exemplary embodiment of the present invention, the evaluation device may further include a working condition control mechanism arranged between the flue gas generation mechanism and the SCR catalytic reaction mechanism. The working condition control mechanism includes a temperature control module and a flow control module. The temperature control module is used to control the test temperature of the coal-fired flue gas, and the flow control module is used to control the test flow rate of the coal-fired flue gas.

[0013] In an exemplary embodiment of the present invention, the evaluation device may further include a tail gas purification mechanism arranged at the end of the SCR catalytic reaction mechanism. The tail gas purification mechanism is used to remove the tail-end pollutants.

[0014] A second aspect of the present invention provides an evaluation method for the low-load operation adaptability of a coal-fired flue gas denitration catalyst. The evaluation method is implemented by the above evaluation device and includes the following steps: using the evaluation device to simulate the denitration reaction process of the denitration catalyst and the coal-fired flue gas to obtain the first NO x concentration test result before poisoning of the denitration catalyst; using the evaluation device to simulate the denitration reaction process of the denitration catalyst poisoned by ABS and the coal-fired flue gas to obtain the second NO xConcentration test results; using the evaluation device to simulate the denitration reaction process of the denitration catalyst after recovering activity from ABS poisoning and coal-fired flue gas, and obtaining the third NO of the denitration catalyst after poisoning recovery x Concentration test results; based on the first NO x Concentration test results, obtaining the initial activity of the denitration catalyst; based on the second NO x Concentration test results and the third NO x Concentration test results, respectively obtaining the first activity and the second activity of the denitration catalyst; based on the initial activity, the first activity and the second activity of the denitration catalyst, determining the process characteristic indexes; by adjusting the flue gas denitration reaction parameters, using the evaluation device to measure the conventional process indexes of the denitration catalyst under different working conditions; based on the process characteristic indexes and the conventional process indexes, evaluating the low-load operation adaptability of the denitration catalyst; wherein, the process characteristic indexes include: the potential of the catalyst to resist ABS poisoning and the ability of the catalyst to recover activity; the conventional process indexes include: denitration efficiency, SO2 / SO3 conversion rate and ammonia slip.

[0015] In another exemplary embodiment of the present invention, the evaluation method may further include: respectively measuring the physical and chemical properties of the denitration catalyst before poisoning, after poisoning, and after poisoning recovery, and obtaining the measured values of the physical and chemical properties of the denitration catalyst before poisoning, after poisoning, and after poisoning recovery; based on the measured values of the physical and chemical properties, determining the physical and chemical property indexes, and the physical and chemical property indexes include: specific surface area potential to resist ABS poisoning, specific surface area recovery ability, pore volume potential to resist ABS poisoning, pore diameter potential to resist ABS poisoning, pore volume recovery ability, pore diameter recovery ability, ABS loading rate and ABS decomposition rate; based on the process characteristic indexes, the physical and chemical property indexes and the conventional process indexes, evaluating the low-load operation adaptability of the denitration catalyst.

[0016] In another exemplary embodiment of the present invention, the determining the process characteristic indexes based on the initial activity, the first activity and the second activity of the denitration catalyst may include: based on the initial activity and the first activity at different flue gas temperatures, determining the potential of the catalyst to resist ABS poisoning at different flue gas temperatures; based on the initial activity and the second activity at different flue gas temperatures, determining the ability of the catalyst to recover activity at different flue gas temperatures.

[0017] In another exemplary embodiment of the present invention, determining the physical and chemical property indexes based on the measured values of the physical and chemical properties of the denitration catalyst before poisoning, after poisoning, and after poisoning recovery may include: testing the initial specific surface area of the denitration catalyst, the first specific surface area of the denitration catalyst after being poisoned by ABS, and the second specific surface area of the denitration catalyst after activity recovery by using a specific surface area analyzer; determining the potential of the specific surface area of the denitration catalyst to resist ABS poisoning based on the initial specific surface area and the first specific surface area; and determining the recovery ability of the specific surface area of the denitration catalyst based on the initial specific surface area and the second specific surface area.

[0018] In another exemplary embodiment of the present invention, determining the physical and chemical property indexes based on the measured values of the physical and chemical properties of the denitration catalyst before poisoning, after poisoning, and after poisoning recovery may further include: testing the initial pore volume and initial pore diameter of the denitration catalyst, the first pore volume and first pore diameter of the denitration catalyst after being poisoned by ABS, and the second pore volume and second pore diameter of the denitration catalyst after activity recovery by using a mercury porosimeter; determining the potential of the pore volume of the denitration catalyst to resist ABS poisoning based on the initial pore volume and the first pore volume; determining the potential of the pore diameter of the denitration catalyst to resist ABS poisoning based on the initial pore diameter and the first pore diameter; determining the recovery ability of the pore volume of the denitration catalyst based on the initial pore volume and the second pore volume; and determining the recovery ability of the pore diameter of the denitration catalyst based on the initial pore diameter and the second pore diameter.

[0019] In another exemplary embodiment of the present invention, determining the physical and chemical property indexes based on the measured values of the physical and chemical properties of the denitration catalyst before poisoning, after poisoning, and after poisoning recovery may further include: testing the initial ammonia content of the denitration catalyst, the first ammonia content of the denitration catalyst after being poisoned by ABS, and the second ammonia content of the denitration catalyst after activity recovery by using an ultraviolet spectrophotometer; determining the ABS loading rate of the denitration catalyst based on the initial ammonia content and the first ammonia content; and determining the ABS decomposition rate of the denitration catalyst based on the initial ammonia content and the second ammonia content.

[0020] Through the technical solution provided by the present invention, the present invention has at least the following technical effects:

[0021] (1) The evaluation device provided by the present invention can realize the integrated detection of SCR denitration catalyst detection and ABS accelerated poisoning inactivation, and conduct an adaptability evaluation on the SCR denitration catalyst, making up for the deficiency that the traditional SCR denitration catalyst detection device can only meet the detection of conventional indexes (such as denitration efficiency, activity, ammonia escape, and SO2 / SO3 conversion rate) and cannot simulate the ABS accelerated poisoning inactivation experiment.

[0022] (2) The evaluation method provided by the present invention provides a new solution for judging the adaptability of SCR denitration catalysts under low load operation, adding the evaluation of process characteristic indicators, physical and chemical characteristic indicators, and the adaptability evaluation of catalysts under different thermal power flue gas conditions, making up for the deficiency of the inability to conduct quality supervision and evaluation on the adaptability of catalysts under low load operation.

[0023] Other features and advantages of the present invention will be described in detail in the following specific implementation section. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The drawings are used to provide a further understanding of the embodiments of the present invention, and constitute a part of the specification. Together with the following specific implementation, they are used to explain the embodiments of the present invention, but do not constitute a limitation to the embodiments of the present invention. In the drawings:

[0025] Figure 1 is a schematic structural diagram of the device for evaluating the adaptability of SCR denitration catalysts under low load operation provided by the embodiment of the present invention;

[0026] Figure 2 is a flowchart of the method for evaluating the adaptability of SCR denitration catalysts under low load operation provided by the embodiment of the present invention. SPECIFIC IMPLEMENTATION MODE

[0027] The following will describe in detail the specific implementation modes of the embodiments of the present invention with reference to the drawings. It should be understood that the specific implementation modes described herein are only used to illustrate and explain the embodiments of the present invention, and are not used to limit the embodiments of the present invention.

[0028] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.

[0029] In the present invention, unless otherwise stated, the orientation words such as "upper, lower, top, bottom" are usually in the direction shown in the drawings or in the vertical, perpendicular or gravitational direction for describing the relative positional relationship of each component. "First", "second", etc. are only for convenience of description and easy distinction, and cannot be understood as indicating or implying relative importance.

[0030] In the description of the present invention, it should also be noted that, unless otherwise clearly defined and limited, terms such as "installation", "connection", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, an indirect connection; it can be a wired connection, or a wireless connection. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0031] Traditional SCR denitration catalyst detection devices can only meet the detection of conventional indicators (denitration efficiency, activity, ammonia slip, and SO2 / SO3 conversion rate), and cannot simulate the ABS accelerated poisoning inactivation experiment. The present invention adds a SO3 generation system and an ABS cleaning system to the traditional SCR detection device, aiming to develop a set of integrated devices for SCR denitration catalyst detection and ABS accelerated poisoning inactivation, and conduct an adaptability evaluation of the SCR denitration catalyst.

[0032] In addition, for the problem that the performance index requirements for the low-load operation of the catalyst have not been clarified and the inspection standard system has not been established, the present invention provides a new solution for the adaptability evaluation of the low-load operation of SCR denitration catalysts, adding the evaluation of process characteristic indicators, physical and chemical characteristic indicators, and the adaptability evaluation of the catalyst under different thermal power flue gas conditions, making up for the lack of quality supervision and evaluation of the adaptability of the catalyst for low-load operation.

[0033] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0034] Example 1

[0035] The first embodiment of the present invention provides an adaptability evaluation device for the low-load operation of an SCR denitration catalyst. The evaluation device includes a flue gas generation mechanism, an SCR catalytic reaction mechanism, and a SO3 generation mechanism.

[0036] The flue gas generation mechanism is used to configure coal-fired flue gas according to the simulated flue gas volume and flue gas components. The SO3 generation mechanism is arranged in parallel with the flue gas generation mechanism and is used to provide SO3. The SCR catalytic reaction mechanism can be only connected to the flue gas generation mechanism and is used to simulate the denitration reaction process of the denitration catalyst and the coal-fired flue gas. The SCR catalytic reaction mechanism can also be simultaneously connected to the flue gas generation mechanism and the SO3 generation mechanism and is used to simulate the denitration reaction process of the denitration catalyst poisoned by ABS and the coal-fired flue gas.

[0037] It should be noted that the purpose of setting the flue gas generation mechanism is to simulate the flue gas composition of thermal power plants. The main components of coal-fired flue gas include NO x , SO2, and NH3, etc., but there are slight differences in the specific components of coal-fired flue gas in different thermal power plants. For example, the flue gas composition of a thermal power plant includes: N2, air, NO x , SO2, and NH3; the flue gas composition of a power plant can also include: SO2, NH3, NO, and NO2.

[0038] The purpose of setting up the SO3 generating mechanism is to add a SO3 intake pipeline so that the flue gas components entering the SCR catalytic reaction mechanism contain sulfur trioxide (SO3), which causes the ABS components in the flue gas to aggregate on the surface and inside of the denitrification catalyst and cause ABS poisoning. The SO3 generating mechanism can directly transport SO3 gas to the SCR catalytic reaction mechanism.

[0039] Furthermore, in order to accelerate the ABS poisoning and deactivation process of the catalyst, SO3 droplets can be delivered to the SCR catalytic reaction mechanism through the SO3 generating mechanism. For example, the SO3 generating mechanism can adjust the concentration of H2O2 and the inlet SO2 according to the SO3 demand, and while adding water, use the oxidizing property of H2O2 to oxidize the SO2 gas in the flue gas to generate SO3 droplets, which then react with NH3 to generate ABS, thereby realizing the ABS accelerated poisoning experiment.

[0040] The purpose of setting up the SCR catalytic reaction mechanism is to load the denitration catalyst, provide space for the denitration reaction, and ensure the smooth flow of flue gas and the uniform distribution of airflow, so as to create conditions for the smooth progress of the denitration reaction. The SCR catalytic reaction mechanism can be used to carry out denitration catalyst activity detection experiments and ABS accelerated poisoning experiments, and then evaluate its activity and other indicators. The SCR catalytic reaction mechanism can include multiple SCR reactors, and by switching the valves, the series or parallel experiments of multi-stage reactors can be realized.

[0041] For example, Figure 1 As shown, the smoke generating mechanism may include a smoke component generating device, a mixer and a preheater. The smoke component generating device may include a N2 gas tank, an air tank, a NO x gas cylinder, SO2 gas cylinder and NH3 gas cylinder. N2 gas cylinder, air tank, NO x Gas cylinders, SO2 gas cylinders and NH3 gas cylinders

[0042] The mixer is used to mix N2, air, and NO x , SO2 and NH3 are mixed to form coal-fired flue gas. The preheater is used to heat the coal-fired flue gas to the test temperature. Two SCR reactors can realize the series or parallel experiment of the secondary reactor by switching valve 1 and valve 2. The SO3 generating mechanism can include a plunger pump, a steam generator and a SO3 generating device. The plunger pump is used to transport H2O2 to the steam generator to mix with water vapor to form H2O2 droplets. After the H2O2 droplets and SO2 gas enter the SO3 generating device, SO3 droplets can be generated after oxidation reaction.

[0043] Further, in this embodiment, the evaluation device may further include an ABS cleaning mechanism, which is disposed in the connecting pipeline between the SCR catalytic reaction mechanism and the SO3 generating mechanism, and is used to remove the blocked ABS in the connecting pipeline. For example, the ABS cleaning mechanism may be a high-power peristaltic pump.

[0044] Further, in this embodiment, the evaluation device may further include a working condition control mechanism disposed between the flue gas generating mechanism and the SCR catalytic reaction mechanism. The working condition control mechanism may include a temperature control module and a flow control module. Among them, the temperature control module is used to control the test temperature of the coal-fired flue gas, and the flow control module is used to control the test flow rate of the coal-fired flue gas.

[0045] Further, in this embodiment, the evaluation device may further include an exhaust gas purification mechanism disposed at the end of the SCR catalytic reaction mechanism, and the exhaust gas purification mechanism is used to remove the end pollutants discharged from the SCR catalytic reaction mechanism.

[0046] It should be noted that the evaluation device should meet the following technical indicators, as shown in Table 1 below.

[0047] Table 1 Main technical indicators of the evaluation device

[0048]

[0049]

[0050] Embodiment 2

[0051] The second embodiment of the present invention provides a method for evaluating the low-load operation adaptability of an SCR denitration catalyst, as Figure 2 shown, the evaluation method includes the following steps.

[0052] Step S101: Carry out a conventional test on the denitration catalyst by using an evaluation device for the low-load operation adaptability of the SCR denitration catalyst to obtain the initial activity of the denitration catalyst.

[0053] Exemplarily, the process of carrying out a conventional test on the denitration catalyst by using an evaluation device for the low-load operation adaptability of the SCR denitration catalyst to obtain the initial activity of the denitration catalyst may include, but is not limited to, the following sub-steps S1011 to S1012.

[0054] Sub-step S1011: Close the SO3 generating mechanism, and according to the simulated flue gas volume and flue gas components, simulate the denitration reaction process of the denitration catalyst and the coal-fired flue gas to obtain the first NO x concentration test result before poisoning of the denitration catalyst.

[0055] For example, the specific process for detecting the activity of the catalyst sample is as follows: Introduce the reaction gas according to the set test conditions, control the ammonia-nitrogen molar ratio to be 1.05, and stabilize for more than 1 h. Then, detect the NO at the outlet and inlet of the reaction device every 0.5 h to 1.0 h. x Concentration. When the results of four consecutive detections do not show the same trend and the relative deviation between any two of them is less than 3%, the test is completed. Take the arithmetic mean of the results of four consecutive determinations as the determination result.

[0056] Step S1012: Calculate the initial activity of the denitration catalyst based on the first NO x concentration test result before poisoning of the denitration catalyst.

[0057] For example, the initial activity K0 of the catalyst can be calculated according to formula (1).

[0058]

[0059] In the formula, K0 is the initial activity of the denitration catalyst, with the unit of meters per hour (m / h); A V is the value of the superficial velocity, with the unit of meters per hour (m / h); C1 is the NO x concentration at the inlet of the reactor (dry basis, reference oxygen content), with the unit of milligrams per cubic meter (mg / m 3 ³); C2 is the NO x concentration at the outlet of the reactor (dry basis, reference oxygen content), with the unit of milligrams per cubic meter (mg / m 3 ³).

[0060] Step S102: Carry out the ABS accelerated poisoning test on the denitration catalyst by using the SCR denitration catalyst low-load operation adaptability evaluation device to obtain the first activity of the denitration catalyst after poisoning.

[0061] Specifically, the specific process of the ABS accelerated poisoning test of the denitration catalyst is as follows: Turn on the SO3 generating mechanism, and simulate the denitration reaction process of the denitration catalyst after ABS poisoning and the coal-fired flue gas under different working conditions (i.e., different flue gas temperatures) by continuously reducing the temperature, and obtain the second NO x concentration test results of the denitration catalyst at different flue gas temperatures; Calculate the first activity of the poisoned denitration catalyst at different flue gas temperatures according to the second NO x concentration test results of the denitration catalyst at different flue gas temperatures.

[0062] For example, the test temperature (i.e., the flue gas temperature) can be adjusted to 350 °C, 320 °C, 300 °C, 280 °C, and 260 °C respectively at decreasing intervals of 3 to 6 h, and the ABS accelerated poisoning experiment is carried out to test the first activity values of the catalyst under different working conditions (i.e., different flue gas temperatures).

[0063] Step S103: Use the SCR denitration catalyst low-load operation adaptability evaluation device to conduct an activity recovery test on the denitration catalyst after poisoning, and obtain the second activity of the denitration catalyst after poisoning recovery.

[0064] Specifically, the specific process of the activity recovery test of the denitration catalyst after poisoning is as follows: Turn on the SO3 generating mechanism, and simulate the flue gas denitration reaction process of the denitration catalyst that has recovered its activity after ABS poisoning and the coal-fired flue gas under different working conditions (i.e., different flue gas temperatures) by continuously raising the temperature, and obtain the third NO x concentration test results of the denitration catalyst at different flue gas temperatures; According to the second NO x concentration test results of the denitration catalyst at different flue gas temperatures, calculate the second activity of the denitration catalyst after activity recovery at different flue gas temperatures.

[0065] For example, after completing the anti-ABS poisoning potential test, the test temperature (i.e., the flue gas temperature) can be adjusted to 280 °C, 300 °C, 320 °C, 350 °C, and 380 °C every 3 - 6 h in an increasing manner to test the second activity of the catalyst under different working conditions (i.e., different flue gas temperatures).

[0066] Taking the honeycomb catalyst as an example, when conducting an initial activity evaluation of the catalyst, open the SCR reactor, load the catalyst sample, and the test flue gas conditions should meet the requirements of the GB / T31587-2017 standard, as shown in Table 2.

[0067] Table 2 Flue gas conditions for initial activity test of honeycomb catalyst

[0068]

[0069] When conducting an anti-ABS poisoning potential experiment on the catalyst, the test flue gas conditions can be experimented according to Table 3 according to the actual situation.

[0070] Table 3 Flue gas parameters for ABS poisoning experiment

[0071]

[0072] When conducting an activity recovery ability experiment on the catalyst, first turn off the special gases (NOx, SO2, and ammonia), conduct experiments at different gradient temperatures, and when the specified temperature is reached, turn on the special gases and test its

[0073] operating condition activity.

[0074] Step S104: Determine the process characteristic indexes at different flue gas temperatures based on the initial activity, the first activity, and the second activity at different flue gas temperatures. Among them, the process characteristic indexes include: the anti-ABS poisoning potential of the catalyst and the catalyst activity recovery ability.

[0075] Exemplarily, the process of determining the process characteristic indexes at different flue gas temperatures based on the initial activity, the first activity, and the second activity of the denitration catalyst at different flue gas temperatures may include, but is not limited to, the following sub-steps S1041 to S1042.

[0076] Sub-step S1041: Determine the anti-ABS poisoning potential of the catalyst at different flue gas temperatures based on the initial activity and the first activity at different flue gas temperatures.

[0077] Sub-step S1042: Determine the catalyst activity recovery ability at different flue gas temperatures based on the initial activity and the second activity at different flue gas temperatures.

[0078] For example, the anti-ABS poisoning potential of the catalyst = the first activity / the initial activity, with the unit of %; the catalyst activity recovery ability = the second activity / the initial activity, with the unit of %.

[0079] Step S105: Measure the physical and chemical properties of the denitration catalyst before poisoning, after poisoning, and after poisoning recovery, and determine the physical and chemical property indexes based on the measured values of the physical and chemical properties.

[0080] Among them, the physical and chemical property indexes include: the specific surface area anti-ABS poisoning potential, the specific surface area recovery ability, the pore volume anti-ABS poisoning potential, the pore diameter anti-ABS poisoning potential, the pore volume recovery ability, the pore diameter recovery ability, the ABS loading rate, and the ABS decomposition rate.

[0081] Exemplarily, the process of measuring the physical and chemical property values of the denitration catalyst before poisoning, after poisoning, and after poisoning recovery, and determining the physical and chemical property indexes based on the measured values of the physical and chemical properties may include, but is not limited to, the following sub-steps S1051 to S1053.

[0082] Sub-step S1051: Use a specific surface area analyzer to determine the specific surface area anti-ABS poisoning potential and the specific surface area recovery ability of the denitration catalyst.

[0083] Specifically, the process of testing the specific surface area anti-ABS poisoning potential and the recovery ability of the catalyst is as follows:

[0084] Sub-sub-step S1051A: Use a specific surface area analyzer to test the initial specific surface area of the denitration catalyst, the first specific surface area of the denitration catalyst after ABS poisoning, and the second specific surface area of the denitration catalyst after activity recovery.

[0085] For example, a specific surface area analyzer can be used to measure the initial specific surface area S0 of the denitration catalyst sample before the experiment (unit: m 2 / g); take the catalyst sample block of the ABS accelerated poisoning experiment (under the test condition of flue gas temperature of 260 °C) as the test sample of the denitration catalyst after ABS poisoning, and use a specific surface area analyzer to measure the first specific surface area S1; take the active recovery sample block (under the test condition of flue gas temperature of 380 °C) as the test sample of the denitration catalyst after activity recovery, and use a specific surface area analyzer to measure the second specific surface area S2.

[0086] Sub-step S1051B: Determine the potential of the specific surface area of the denitration catalyst to resist ABS poisoning based on the initial specific surface area and the first specific surface area.

[0087] Sub-step S1051C: Determine the recovery ability of the specific surface area of the denitration catalyst based on the initial specific surface area and the second specific surface area.

[0088] For example, the potential of the specific surface area to resist ABS poisoning = the first specific surface area / the initial specific surface area; the recovery ability of the specific surface area = the second specific surface area / the initial specific surface area.

[0089] Sub-step S1052: Use a mercury intrusion porosimeter to measure the potential of the pore volume and pore diameter of the denitration catalyst to resist ABS poisoning and the recovery ability of the pore volume and pore diameter.

[0090] Specifically, the process for measuring the potential of the pore volume and pore diameter of the catalyst to resist ABS poisoning and the recovery ability is as follows:

[0091] Sub-step S1052A: Use a mercury intrusion porosimeter to measure the initial pore volume and initial pore diameter of the denitration catalyst, the first pore volume and first pore diameter of the denitration catalyst after ABS poisoning, and the second pore volume and second pore diameter of the denitration catalyst after activity recovery.

[0092] For example, a mercury intrusion porosimeter can be used to measure the initial pore volume V of the denitration catalyst sample before the experiment p0 (unit: cc / g) and the initial pore diameter d p0 (unit: nm); take the catalyst sample block of the ABS accelerated poisoning experiment (under the test condition of flue gas temperature of 260 °C) as the test sample of the denitration catalyst after ABS poisoning, and use a mercury intrusion porosimeter to measure the first pore volume V p1 and the first pore diameter d p1 ; take the active recovery sample block (under the test condition of flue gas temperature of 380 °C) as the test sample of the denitration catalyst after activity recovery, and use a mercury intrusion porosimeter to measure the second pore volume V p2 and the second pore diameter d p2 .

[0093] Sub-step S1052B: Determine the potential of the pore volume of the denitration catalyst to resist ABS poisoning based on the initial pore volume and the first pore volume.

[0094] Sub-step S1052C: Determine the pore size anti-ABS poisoning potential of the denitration catalyst based on the initial pore size and the first pore size.

[0095] Sub-step S1052D: Determine the pore volume recovery ability of the denitration catalyst based on the initial pore volume and the second pore volume.

[0096] Sub-step S1052E: Determine the pore size recovery ability of the denitration catalyst based on the initial pore size and the second pore size.

[0097] For example, the pore volume anti-ABS poisoning potential = the first pore volume / the initial pore volume; the pore volume recovery ability = the second pore volume / the initial pore volume; the pore size anti-ABS poisoning potential = the first pore size / the initial pore size; the pore size recovery ability = the second pore size / the initial pore size.

[0098] Sub-step S1053: Use an ultraviolet spectrophotometer to test the ABS loading rate and the ABS decomposition rate of the denitration catalyst.

[0099] Specifically, the process for testing the ABS loading rate and the decomposition rate of the catalyst is as follows:

[0100] Sub-step S1053A: Use an ultraviolet spectrophotometer to test the initial ammonia content of the denitration catalyst, the first ammonia content of the denitration catalyst after ABS poisoning, and the second ammonia content of the denitration catalyst after activity recovery.

[0101] For example, the initial ammonia content ρ0(NH3) (unit: mg / m 3 ) of the denitration catalyst sample before the experiment can be tested using an ultraviolet spectrophotometer; take the catalyst sample block in the ABS accelerated poisoning experiment (under the test condition of a flue gas temperature of 260 °C) as the test sample of the denitration catalyst after ABS poisoning, and use an ultraviolet spectrophotometer to test the first ammonia content ρ1(NH3); take the activity recovery sample block (under the test condition of a flue gas temperature of 380 °C) as the test sample of the denitration catalyst after activity recovery, and use an ultraviolet spectrophotometer

[0102] to test the second ammonia content ρ2(NH3).

[0103] Sub-step S1053B: Determine the ABS loading rate of the denitration catalyst based on the initial ammonia content and the first ammonia content.

[0104] Sub-step S1053C: Determine the ABS decomposition rate of the denitration catalyst based on the initial ammonia content and the second ammonia content.

[0105] For example, the ABS loading rate of the denitration catalyst = the first ammonia content / the initial ammonia content; the ABS decomposition rate of the denitration catalyst = the second ammonia content / the initial ammonia content.

[0106] Step S106: By adjusting the flue gas denitration reaction parameters, use the evaluation device to measure the conventional process indicators of the denitration catalyst under different working conditions.

[0107] That is, by simulating the actual flue gas environment and catalyst layout of different thermal power plants, conduct an adaptability evaluation of the catalyst under low-load operation.

[0108] Among them, the flue gas denitration reaction parameters include: flue gas volume, catalyst volume, designed ammonia-nitrogen molar ratio, designed denitration efficiency, designed flue gas temperature, moisture content, oxygen content, nitrogen oxide concentration, and sulfur oxide concentration; the conventional process indicators include: denitration efficiency, SO2 / SO3 conversion rate, and ammonia slip.

[0109] When conducting an adaptability evaluation of the catalyst under different thermal power plant flue gas conditions, use a full-scale process performance test bench to simulate the actual flue gas environment of the power plant (for example, change the concentration of flue gas components) and the catalyst layout, and conduct tests on indicators such as denitration efficiency, SO2 / SO3 conversion rate, and ammonia slip during low-load operation of the catalyst, and then evaluate whether the catalyst meets the design requirements.

[0110] The denitration efficiency of the catalyst can be calculated according to formula (2).

[0111]

[0112] In the formula, C1 is the NO concentration at the reactor inlet, in mg / m³; x C2 is the NO concentration at the reactor outlet, in mg / m³; 3 η is the denitration efficiency of the catalyst (under the condition that the ammonia-nitrogen molar ratio at the reactor inlet is 1.05), expressed as a percentage (%). x 3 3 3

[0113] The SO2 / SO3 conversion rate of the catalyst can be calculated according to formula (3).

[0114]

[0115] In the formula, X is the SO2 / SO3 conversion rate of the catalyst, expressed as a percentage (%); SO3 is the value of the SO3 volume fraction at the reactor outlet (dry basis, reference oxygen content), in microliters per liter (μL / L); SO3in is the value of the SO3 volume fraction at the reactor inlet (dry basis, reference oxygen content), in microliters per liter (μL / L); SO2in is the value of the SO2 volume fraction at the reactor inlet (dry basis, reference oxygen content), in microliters per liter (μL / L). 3,out 3,in 3,in 3,in 2,in 2,in

[0116] The ammonia slip can be calculated according to formula (4).

[0117]

[0118] Wherein, C NH3 is the ammonia slip converted to the standard state, dry basis, and reference oxygen content, with the unit of milligram per cubic meter (mg / m 3 ); C' NH3 is the ammonia slip converted to the standard state, dry basis, and actual oxygen content, with the unit of milligram per cubic meter (mg / m 3 ); O2 is the reference oxygen content, expressed as a percentage (%); O'2 is the measured O2 concentration at the reactor outlet, expressed as a percentage (%).

[0119] Step S107: Based on the process characteristic indexes, physical and chemical characteristic indexes, and conventional process indexes, jointly evaluate the low-load operation adaptability of the denitration catalyst.

[0120] The evaluation method of the present invention evaluates the low-load operation adaptability of the SCR denitration catalyst from three aspects, which are: ① Evaluation of process characteristic indexes; ② Evaluation of physical and chemical characteristic indexes; ③ Evaluation of the adaptability of the catalyst under different thermal power flue gas conditions.

[0121] When it is determined that both the process characteristic indexes and physical and chemical characteristic indexes of the catalyst are within the respective specified threshold ranges, and the conventional process indexes of the catalyst meet the design requirements, it can be considered that the catalyst has low-load operation adaptability.

[0122] The preferred embodiments of the present invention have been described in detail above in conjunction with the accompanying drawings. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0123] In addition, it should be noted that, in the case of no contradiction, the various specific technical features described in the above specific embodiments can be combined in any suitable way. To avoid unnecessary repetition, the present invention will not separately describe various possible combination ways.

[0124] In addition, any combination can be made between different embodiments of the present invention as long as it does not violate the idea of the present invention, and it should also be regarded as the content disclosed by the present invention.

Claims

1. A method for evaluating the adaptability of a denitration catalyst for coal-fired flue gas under low load operation, characterized in that, The evaluation method is realized by a low-load operation adaptability evaluation device for a coal-fired flue gas denitration catalyst. The evaluation device includes: a flue gas generation mechanism, an SCR catalytic reaction mechanism, and an SO3 generation mechanism; The flue gas generation mechanism is used to configure coal-fired flue gas according to the simulated flue gas volume and flue gas components; The SO3 generation mechanism is used to provide SO3; The SCR catalytic reaction mechanism is connected to the flue gas generation mechanism and is used to simulate the denitration reaction process of the denitration catalyst and the coal-fired flue gas; The SCR catalytic reaction mechanism is also connected to the SO3 generation mechanism and is used to simulate the denitration reaction process of the denitration catalyst poisoned by ABS and the coal-fired flue gas; The evaluation method includes the following steps: Using the evaluation device to simulate the denitration reaction process of the denitration catalyst and coal-fired flue gas, and obtaining the first NO x concentration test result before the denitration catalyst is poisoned; Use the evaluation device to simulate the denitration reaction process of the denitration catalyst after being poisoned by ABS and coal-fired flue gas, and obtain the second NO of the denitration catalyst after being poisoned x concentration test result; Using the evaluation device to simulate the flue gas denitrification reaction process between the denitrification catalyst that has recovered its activity after being poisoned by ABS and the coal-fired flue gas, and obtaining the third NO x concentration test result after the denitrification catalyst has recovered from poisoning; Based on the first NO x concentration test results, the initial activity of the denitration catalyst is obtained; Based on the second NO x concentration test result and the third NO x concentration test result, the first activity and the second activity of the denitration catalyst are obtained respectively; Based on the initial activity, the first activity, and the second activity, determine the process characteristic indexes, and the process characteristic indexes include: the ABS poisoning resistance potential of the catalyst and the catalyst activity recovery ability; By adjusting the flue gas denitration reaction parameters, use the evaluation device to measure the conventional process indexes of the denitration catalyst under different working conditions, and the conventional process indexes include: denitration efficiency, SO2 / SO3 conversion rate, and ammonia slip; Measure the physical and chemical properties of the denitration catalyst before poisoning, after poisoning, and after poisoning recovery respectively, and obtain the measured values of the physical and chemical properties of the denitration catalyst before poisoning, after poisoning, and after poisoning recovery; Based on the measured values of the physical and chemical properties of the denitration catalyst before poisoning, after poisoning, and after poisoning recovery, determine the physical and chemical property indexes, and the physical and chemical property indexes include: specific surface area ABS poisoning resistance potential, specific surface area recovery ability, pore volume ABS poisoning resistance potential, pore diameter ABS poisoning resistance potential, pore volume recovery ability, pore diameter recovery ability, ABS loading rate, and ABS decomposition rate; Based on the process characteristic indexes, the physical and chemical property indexes, and the conventional process indexes, evaluate the low-load operation adaptability of the denitration catalyst; Among them, the determining the physical and chemical property indexes based on the measured values of the physical and chemical properties of the denitration catalyst before poisoning, after poisoning, and after poisoning recovery includes: Use a specific surface area analyzer to test the initial specific surface area of the denitration catalyst, the first specific surface area of the denitration catalyst after being poisoned by ABS, and the second specific surface area of the denitration catalyst after activity recovery; Based on the initial specific surface area and the first specific surface area, determine the specific surface area ABS poisoning resistance potential of the denitration catalyst; Based on the initial specific surface area and the second specific surface area, determine the specific surface area recovery ability of the denitration catalyst.

2. The method for evaluating the adaptability of a coal-fired flue gas denitration catalyst to low-load operation according to claim 1, wherein The evaluation device further includes an ABS cleaning mechanism, and the ABS cleaning mechanism is arranged in the connecting pipeline between the SCR catalytic reaction mechanism and the SO3 generation mechanism and is used to remove the blocked ABS in the connecting pipeline.

3. The method for evaluating the adaptability of a coal-fired flue gas denitration catalyst to low-load operation according to claim 1, wherein, The evaluation device further includes a working condition control mechanism arranged between the flue gas generation mechanism and the SCR catalytic reaction mechanism. The working condition control mechanism includes a temperature control module and a flow control module. The temperature control module is used to control the test temperature of the coal-fired flue gas, and the flow control module is used to control the test flow rate of the coal-fired flue gas.

4. The method for evaluating the adaptability of a coal-fired flue gas denitration catalyst to low-load operation according to claim 1, characterized in that, The evaluation device further includes a tail gas purification mechanism arranged at the end of the SCR catalytic reaction mechanism, and the tail gas purification mechanism is used to remove the end pollutants.

5. The method for evaluating the adaptability of a coal-fired flue gas denitration catalyst to low-load operation according to claim 1, wherein Determine the process characteristic indexes based on the initial activity, the first activity, and the second activity, including: Determine the potential of the catalyst to resist ABS poisoning at different flue gas temperatures based on the initial activity and the first activity at different flue gas temperatures; Determine the activity recovery ability of the catalyst at different flue gas temperatures based on the initial activity and the second activity at different flue gas temperatures.

6. The method for evaluating the adaptability of a coal-fired flue gas denitration catalyst to low-load operation according to claim 1, wherein The determination of the physical and chemical property indexes based on the measured values of the physical and chemical properties of the denitration catalyst before poisoning, after poisoning, and after poisoning recovery further includes: Use a mercury intrusion porosimeter to test the initial pore volume and initial pore diameter of the denitration catalyst, the first pore volume and first pore diameter of the denitration catalyst after ABS poisoning, and the second pore volume and second pore diameter of the denitration catalyst after activity recovery; Determine the potential of the pore volume of the denitration catalyst to resist ABS poisoning based on the initial pore volume and the first pore volume; Determine the potential of the pore diameter of the denitration catalyst to resist ABS poisoning based on the initial pore diameter and the first pore diameter; Determine the pore volume recovery ability of the denitration catalyst based on the initial pore volume and the second pore volume; Determine the pore diameter recovery ability of the denitration catalyst based on the initial pore diameter and the second pore diameter.

7. The method for evaluating the adaptability of a coal-fired flue gas denitration catalyst to low-load operation according to claim 1, characterized in that, The determination of the physical and chemical property indexes based on the measured values of the physical and chemical properties of the denitration catalyst before poisoning, after poisoning, and after poisoning recovery further includes: Use an ultraviolet spectrophotometer to test the initial ammonia content of the denitration catalyst, the first ammonia content of the denitration catalyst after ABS poisoning, and the second ammonia content of the denitration catalyst after activity recovery; Determine the ABS loading rate of the denitration catalyst based on the initial ammonia content and the first ammonia content; Determine the ABS decomposition rate of the denitration catalyst based on the initial ammonia content and the second ammonia content.

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