Volume adjustable denitration reactor, low-temperature denitration catalyst measurement system and method

Abstract

The present application belongs to the technical field of low-temperature denitration catalyst performance evaluation, and particularly relates to a denitration reactor with adjustable volume, a low-temperature denitration catalyst measuring system and a method. The denitration reactor comprises a cylinder and a heating component arranged on the outer wall of the cylinder, and the upper part and the lower part of the cylinder are respectively provided with a gas inlet and a gas outlet. A support rod is fixed to the inner side of the bottom of the cylinder, and a lining plate with adjustable fixed position is arranged on the support rod. In use, the fixed position of the lining plate on the support rod is adjusted so that the center position of the catalyst bed layer above the lining plate is at the same level as the center of the heating component, and the lining plate divides the cylinder into two cavities, and the upper cavity is a denitration reaction zone. The denitration reactor has a movable lining plate inside, and the volume of the denitration catalyst reaction can be changed by moving the lining plate during use, so that the to-be-tested catalyst is always located at the center position of the uniform temperature zone, and the low-temperature denitration catalyst can be tested in a large range of space velocities.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of low-temperature denitration catalyst performance evaluation, and particularly relates to a volume-adjustable denitration reactor, a low-temperature denitration catalyst measuring system and a method. BACKGROUND

[0002] The common sintering flue gas denitration process at present is an SCR denitration process, which uses ammonia as a reducing agent to reduce NOx in sintering flue gas. x Under the action of an SCR catalyst, the NOx is reduced into N2, and the catalyst in the process has a higher requirement for reaction temperature. The most common SCR denitration catalyst has a catalytic temperature of 280-320 DEG C. Since the NOx concentration in sintering flue gas is low, the flue gas needs to be heated to a high temperature before entering the denitration reactor, which causes a large amount of energy consumption. x The treatment device is generally arranged after desulfurization, and the flue gas temperature at this position is low and cannot reach the temperature range of the catalyst. Therefore, the flue gas needs to be heated again in the actual operation process, which causes a large amount of energy consumption. The development of a low-temperature denitration catalyst can make the process technology stably operate at a lower flue gas temperature, and the flue gas does not need to be heated, which can effectively reduce the energy consumption of the denitration process. At present, most of the low-temperature denitration catalysts are still in the laboratory development stage, and therefore it is of great significance to accurately verify the denitration capacity of the catalyst in the laboratory.

[0003] At present, most of the denitration catalyst reactors in China adopt a fixed bed design, which has the advantages of simple operation and convenient catalyst loading. However, the current various denitration catalyst evaluation devices are innovated in control, detection and process, and are not innovated in the related design of the reactor itself, which leads to the fact that the catalyst cannot be directly placed in the constant temperature zone of the external heating furnace during the catalyst loading process due to the limitation of the traditional reactor. The conventional method in China is to fix the effective volume of the reactor and increase the length of the constant temperature heating furnace outside the reactor, so as to ensure that the catalyst is in the constant temperature zone, and then the space velocity is controlled by adjusting the flow of the system. In the above method, each reactor has a fixed catalyst loading amount, and when the catalyst loading amount exceeds the fixed amount, the device cannot meet the test, and the reactor needs to be redesigned. When the diameter of the reactor increases, there is a large diameter difference between the inlet pipeline and the reactor, and the gas flow is easily segregated in the reactor, which affects the test results. SUMMARY

[0004] The present application aims at the defect that the fixed volume of the denitration reactor in the prior art is not conducive to the performance evaluation of different amounts of catalysts, and thus proposes a denitration reactor with adjustable volume, a low-temperature denitration catalyst measuring system and method. The denitration reactor has a movable lining plate inside. During actual operation, the volume of the denitration catalytic reaction can be changed by moving the lining plate, so that the catalyst bed layer can be located at the center of the constant temperature zone of the external heating furnace, thereby meeting the demand that the low-temperature denitration catalyst can be tested in a larger air velocity range.

[0005] The first aspect of the present application proposes a denitration reactor with adjustable volume, which comprises a cylinder and a heating component arranged on the outer wall of the cylinder. The upper part and the lower part of the cylinder are respectively provided with a gas inlet and a gas outlet. A support rod is fixed to the inner side of the bottom of the cylinder, and a lining plate with adjustable fixed position is arranged on the support rod. In use, the fixed position of the lining plate on the support rod is adjusted so that the center position of the catalyst bed layer above the lining plate is at the same level as the center of the heating component. The lining plate divides the cylinder into two cavities, and the upper cavity is a denitration reaction zone.

[0006] Preferably, the lining plate is a disc structure with multiple layers of circular holes with gradually increasing inner diameters arranged from inside to outside.

[0007] Preferably, a gas flow uniformization fan is arranged on the inner side of the top of the cylinder, which is used to uniformly distribute the gas flow in the cylinder for the first time.

[0008] More preferably, a gas flow distribution baffle is arranged below the gas flow uniformization fan and below the gas inlet, which is used to uniformly distribute the gas flow in the cylinder for the second time.

[0009] Further preferably, a plurality of circular holes with uniform size are arranged on the gas flow distribution baffle.

[0010] The second aspect of the present application proposes a low-temperature denitration catalyst measuring system, which comprises the above-mentioned denitration reactor with adjustable volume, a mass flow meter and an online tail gas monitoring device. The denitration reactor is used to perform a denitration reaction on the input ammonia gas and flue gas under the action of the denitration catalyst in the catalyst bed layer. The mass flow meter is used to measure the flow rates of the ammonia gas and the flue gas before entering the denitration reactor for denitration reaction. The online tail gas monitoring device is used to detect the composition of the flue gas after denitration reaction in the denitration reactor.

[0011] Preferably, the system further comprises a pressure sensor for measuring the pressure inside the cylinder, a temperature sensor for measuring the temperature inside the cylinder and the heating component, and a pre-heater between the connection pipeline of the mass flow meter and the gas inlet, which is used to heat the flue gas before the denitration reaction.

[0012] More preferably, the system further comprises a control unit for monitoring and controlling the denitration reactor, the mass flow meter, the tail gas online monitoring device, the pressure sensor, the temperature sensor, and the pre-heater.

[0013] The third aspect of the present application provides a method for measuring a low-temperature denitration catalyst according to the above-mentioned system, which comprises: adjusting the fixed position of the lining plate on the support rod so that the center position of the catalyst bed above the lining plate is at the same level as the center of the heating component, and adjusting the temperature of the heating component to the catalytic temperature; adjusting the space velocity of the denitration reaction according to the total flow rate of the ammonia gas and the flue gas before denitration and the amount of denitration catalyst; discharging the flue gas after denitration from the gas outlet and into the tail gas online monitoring device, and detecting the composition and content of the flue gas after denitration by using the tail gas online monitoring device.

[0014] Preferably, the calculation formula for adjusting the space velocity of the denitration reaction according to the total flow rate of the ammonia gas and the flue gas before denitration and the amount of denitration catalyst is as follows:

[0015]

[0016] In the formula, Q is the total flow rate of the ammonia gas and the flue gas before denitration, L / min; H is the reaction space velocity, h -1 ; V is the volume of the denitration catalyst, mL.

[0017] In the volume-adjustable denitration reactor, the low-temperature denitration catalyst measurement system, and the method according to the present application, at least the following beneficial effects are achieved:

[0018] (1) The denitration reactor according to the present application has a movable lining plate inside, and by moving the lining plate during use, the volume of the denitration catalyst reaction can be changed, ensuring that the catalyst to be measured is always at the center position of the uniform temperature zone, thereby meeting the demand that the low-temperature denitration catalyst can be tested at a larger space velocity range. Therefore, compared with the traditional laboratory denitration reactor, the present application can evaluate the performance of different amounts of catalysts using one set of device, has strong operability, and the measurement results are more accurate.

[0019] (2) In this invention, an airflow distribution fan is installed at the reactor inlet to ensure uniform airflow distribution inside the reactor under the condition of large inner diameter, avoid problems such as flue gas segregation during the test, and improve the accuracy of measurement results; at the same time, the system described in this invention is equipped with an online tail gas monitoring device, which can directly calculate data such as denitrification efficiency of the reaction process, thereby improving measurement efficiency. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of a low-temperature denitrification catalyst measurement system according to one embodiment of the present invention;

[0021] Figure 2 This is a schematic diagram of the structure of a liner plate according to one embodiment of the present invention;

[0022] Figure 3 This is a schematic diagram of the airflow distribution baffle according to one embodiment of the present invention;

[0023] Figure 4 This is a flowchart illustrating the use of an adjustable-volume denitrification reactor according to one embodiment of the present invention.

[0024] Figure Labels

[0025] 1. Shell; 2. Heating component; 3. Support rod; 4. Liner; 5. Catalyst bed; 6. Airflow distribution fan; 7. Airflow distribution baffle; 8. Mass flow meter; 9. Exhaust gas online monitoring device; 10. Pressure sensor; 11. Temperature sensor; 12. Preheater; 13. Control unit; 14. Hollow tube; 15. Fiber cotton layer; 16. Central shaft; 17. Baffle. Detailed Implementation

[0026] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0027] The first aspect of this invention provides a volume-adjustable denitrification reactor, such as... Figure 1 As shown, the denitrification reactor includes a cylindrical body 1 and a heating element 2 disposed on the outer wall of the cylindrical body 1. The upper and lower parts of the cylindrical body 1 have a gas inlet and a gas outlet, respectively. A support rod 3 is fixed to the inner side of the bottom of the cylindrical body 1, and a fixed-position adjustable liner 4 is disposed on the support rod 3. In use, the fixed position of the liner 4 on the support rod 3 is adjusted so that the center position of the catalyst bed 5 located above the liner 4 is at the same level as the center of the heating element 2. The liner 4 divides the cylindrical body 1 into upper and lower chambers, with the upper chamber being the denitrification reaction zone.

[0028] In the specific embodiment of the denitration reactor, the cylinder 1 has an upper sealing cover and a lower sealing cover, and the upper and lower ends of the cylinder 1 are provided with threads matched with the sealing covers for sealing the upper and lower sealing covers.

[0029] In the specific embodiment of the denitration reactor, the heating component 2 is a heating bushing, and a circular partition plate 17 is arranged below the gas inlet of the cylinder 1, which is used to fix the cylinder 1 in the outer heating component 2, and the heating component 2 is located between the gas inlet and the gas outlet. In this embodiment, the heating bushing is designed as a ring-shaped openable and closable structure, and the heating bushing is electrically heated, and is provided with three temperature control sections, which can be set respectively, and the temperature control range is 20-300℃, and the heating bushing is provided with a signal transmission function, and the temperature parameter can be directly controlled by the control unit 13.

[0030] In the specific embodiment of the denitration reactor, as shown in Figure 2 the lining plate 4 is designed as a disc structure with multiple layers of circular holes with gradually increasing inner diameters arranged from inside to outside, and the center of the lining plate 4 has a circular hole for connecting the hollow pipe 14, the hollow pipe 14 is provided with a fixing nut on the pipe wall, the inner diameter of the hollow pipe 14 matches the outer diameter of the support rod 3, and the hollow pipe 14 is sleeved on the support rod 3; the support rod 3 penetrates through the catalyst bed 5, and the support rod 3 is welded with the lower sealing cover, and the top end of the support rod 3 is located below the gas inlet. In actual operation, the position of the lining plate 4 on the support rod 3 is moved until the center of the catalyst bed 5 above the lining plate 4 is at the same level as the center of the heating component 2, which is the specified position, the volume of the denitration catalytic reaction can be changed, and then the lining plate 4 is fixed on the support rod 3 by the fixing nut. In this embodiment, the support rod 3 is designed as a hollow structure, and a thermocouple can be inserted in the middle to measure the temperature of the catalyst bed 5 in the cylinder 1.

[0031] In the specific embodiment of the denitration reactor, the inner side of the upper sealing cover of the cylinder 1 is provided with a rotatable central shaft 16 connected with an airflow distribution fan 6 located at the gas inlet. The airflow distribution fan 6 is driven by the flue gas conveyed into the cylinder 1, and the airflow in the cylinder 1 can be homogenized by the gas flow rate in the cylinder 1.

[0032] In the preferred embodiment of the denitration reactor, a gas flow distribution baffle 7 is arranged below the gas flow uniformization fan 6 and below the gas inlet, and the gas flow distribution baffle 7 is used for secondary uniformization of the gas flow inside the cylinder 1. Specifically, as shown in Figure 3 FIG. 3, the gas flow distribution baffle 7 is provided with multiple layers of uniform circular holes, which is more conducive to uniformization of the gas flow.

[0033] In the specific embodiment of the denitration reactor, when the catalyst in the catalyst bed 5 is in powder form, a layer of fire-resistant fiber cotton layer 14 is laid on the lining plate 4, and the fiber cotton layer 14 is compacted to ensure that the powder catalyst can stay in the middle position between the lining plate 4 and the cylinder 1. After loading, the powder catalyst should be slightly flattened and compacted, and a layer of fire-resistant fiber cotton layer 14 is covered on the catalyst bed 5 for plugging.

[0034] The second aspect of the present application provides a low-temperature denitration catalyst measurement system, which comprises the volume-adjustable denitration reactor, a mass flow meter 8 and an exhaust gas online monitoring device 9. The denitration reactor is used for denitration reaction of input ammonia and flue gas under the action of the denitration catalyst in the catalyst bed 5. The mass flow meter 8 is used to measure the flow of ammonia and flue gas before entering the denitration reactor for denitration reaction. The exhaust gas online monitoring device 9 is used to detect the composition of the flue gas after denitration reaction in the denitration reactor.

[0035] In the specific embodiment of the system, the denitration catalyst can be a honeycomb denitration catalyst, a granular denitration catalyst or a powder denitration catalyst.

[0036] In the specific embodiment of the system, the mass flow meter 8 is directly connected to the gas path after pressure reduction, and the mass flow meter 8 is selected to be corrosion-resistant to prevent corrosion of ammonia, NO x , etc. The range is (0-10L / min). Specifically, as shown in Figure 1 , ammonia enters from the gas path 1 and passes through the mass flow meter 8 to measure the ammonia flow, and the flue gas enters from the gas path 2 and passes through the mass flow meter 8 to measure the flue gas flow. Ammonia and flue gas are combined and enter the cylinder 1 from the gas inlet.

[0037] In the specific embodiment of the system, the exhaust gas online monitoring device 9 is in communication with the gas outlet, and the exhaust gas online monitoring device 9 is mainly a flue gas analyzer, which has the function of detecting NO x , NH3, O2 and SO2, etc. in the flue gas, and the range is 0-1000mg / m 3 .

[0038] In the specific embodiment of the system described in the present application, the system further comprises a pressure sensor 10 for measuring the pressure inside the cylinder 1, a temperature sensor 11 for measuring the temperature inside the cylinder 1 and the heating component 2, and a preheater 12. Figure 1 As shown in the drawings, the bottom of the cylinder 1 is provided with a temperature sensor 11 for measuring the temperature inside the cylinder 1, mainly detecting the temperature of the catalyst bed, and the heating component 2 is provided with three-stage temperature control, which has been described above and will not be repeated here. Three temperature sensors 11 are arranged at the three-stage temperature control of the heating component 2 to measure the temperature at the three-stage temperature control, respectively, for temperature monitoring for feedback control of the control unit 13. The preheater 12 is located between the mass flow meter 8 in the gas path 2 and the connecting pipeline of the gas inlet, and is used to warm up the flue gas before the denitration reaction.

[0039] In this context, the pressure sensor 10 is a digital pressure sensor with a range of (-0.1 ~ 100kPa), a minimum response signal of 1Pa, and a response time of ≤10ms. The pressure signal is directly transmitted to the control unit 13, which can monitor and display the pressure change inside the cylinder 1 in real time.

[0040] In this context, the temperature sensor 11 is a K-type armored thermocouple with a range of (0 ~ 500℃) and a minimum response signal of 0.1℃. The thermocouple signal is directly transmitted to the control unit 13, which can monitor and display the temperature of the preheater 12, the heating component 2 and the inside of the cylinder 1 in real time.

[0041] In this context, the preheater 12 is designed with electric heating, which can realize the warming up of the reaction gas, with a warming up range of (20 ~ 300℃). The preheater 12 is equipped with signal input and output, which can be connected to the control unit 13 and controlled by the control unit 13.

[0042] In this context, the preheater 12 is designed with electric heating, which can realize the warming up of the reaction gas, with a warming up range of (20 ~ 300℃). The preheater 12 is equipped with signal input and output, which can be connected to the control unit 13 and controlled by the control unit 13.

[0043] The specific operation process of the low-temperature denitration catalyst measurement system is as follows: S01: before the test, the amount of the denitration catalyst to be measured is determined first, and the weight and volume of the denitration catalyst are measured and recorded using an analytical balance; S02: the lower sealing cover of the cylinder body 1 is opened, the lining plate 4 on the support rod 3 welded with the lower sealing cover is taken out, and the residual catalyst in the cylinder body 1 is removed; S03: the fixed position of the lining plate 4 this time is determined according to the volume of the catalyst and the inner diameter of the cylinder body 1, and the lining plate 4 is fixed on the support rod 3 using fastening screws, so that the denitration catalyst to be measured is ensured to be located in the middle position of the constant temperature zone of the heating component 2 (heating bushing) outside the cylinder body 1; S04: the filling method of the catalyst in the cylinder body 1 is determined according to the type of the denitration catalyst to be measured; when the denitration catalyst to be measured is in powder form, a layer of fire-resistant fiber cotton layer 15 needs to be laid on the lining plate 4 and compacted, so that the powder catalyst can stay in the middle position of the lining plate 4 and the cylinder body 1; if the catalyst is in granular form and the particle size is greater than the air permeable hole on the lining plate 4, the catalyst can be directly filled; S05: the support rod 3 with the lining plate 4 is loaded into the cylinder body 1, and the lower sealing cover is tightened; the upper sealing cover is opened, the airflow distribution fan 6 and the airflow distribution partition plate 7 in the cylinder body 1 are taken out, and the denitration catalyst to be measured is loaded from the upper part of the cylinder body 1; S06: the airflow distribution fan 6 and the airflow distribution partition plate 7 in the upper part of the cylinder body 1 are loaded back, the upper sealing cover is tightened, and the matching pipeline of the cylinder body 1 is connected; S07: the airtightness of the cylinder body 1 is checked; if the airtightness of the cylinder body 1 fails the check, the dew point position needs to be investigated and repaired until the airtightness check is passed; when the cylinder body 1 passes the airtightness check, the filling of the catalyst and the preliminary equipment preparation work are completed, and the test is ready to start.

[0044] The third aspect of the present application proposes a low-temperature denitration catalyst measurement method according to the above-mentioned system, which comprises: adjusting the fixed position of the lining plate 4 on the support rod 3, so that the center position of the catalyst bed 5 located above the lining plate 4 is at the same level as the center of the heating component 2, and adjusting the temperature of the heating component 2 to the catalytic temperature; the ammonia gas and the flue gas before denitration pass through the mass flow meter 8 to measure the flow rate, and enter the inside of the cylinder body 1 from the gas inlet; the ammonia gas and the flue gas react with the denitration catalyst in the catalyst bed 5, and the space velocity of the denitration reaction is adjusted according to the total flow rate of the ammonia gas and the flue gas before denitration and the amount of the denitration catalyst; the flue gas after denitration is discharged from the gas outlet and enters the tail gas online monitoring device 10, and the composition and content of the flue gas after denitration are detected by the tail gas online monitoring device 10.

[0045] In the specific implementation of the method, during the denitration reaction, the temperature of the inside of the cylinder body 1 and the heating component 2 is measured by the temperature sensor 9, and the heating component 2 is adjusted to the catalytic temperature in real time.

[0046] In the specific embodiment of the method of the present application, the formula for calculating the space velocity of the denitration reaction is as follows, according to the total flow of the ammonia gas and the flue gas before denitration and the amount of the denitration catalyst:

[0047]

[0048] In the formula, Q is the total flow of the ammonia gas and the flue gas before denitration, L / min; H is the reaction space velocity, h -1 ; V is the volume of the denitration catalyst, mL.

[0049] The above describes the preferred embodiments of the present application, but the present application is not limited thereto. Within the technical concept of the present application, various simple modifications can be made to the technical solutions of the present application, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be considered as the disclosed content of the present application, and all fall within the protection scope of the present application.

Claims

1. A low-temperature denitrification catalyst measurement system, characterized in that, The system includes a volume-adjustable denitrification reactor, a mass flow meter (8), and an online tail gas monitoring device (9); the denitrification reactor includes a cylinder (1) and a heating element (2) disposed on the outer wall of the cylinder (1), the upper and lower parts of the cylinder (1) respectively have a gas inlet and a gas outlet; a support rod (3) is fixed on the inner side of the bottom of the cylinder (1), and a fixed-position adjustable liner (4) is disposed on the support rod (3); in use, the fixed position of the liner (4) on the support rod (3) is adjusted so that the center position of the catalyst bed (5) located above the liner (4) is at the same level as the center of the heating element (2), the liner (4) divides the cylinder (1) into upper and lower cavities, the upper cavity being the denitrification reaction zone; the liner (4) is a circular liner with multiple layers of circular holes with gradually increasing inner diameter arranged from the inside to the outside. The system includes a disc structure; the denitrification reactor is used to denitrate the input ammonia and flue gas under the action of the denitrification catalyst in the catalyst bed (5); the mass flow meter (8) measures the flow rates of ammonia and flue gas before entering the denitrification reactor for denitrification reaction; the tail gas online monitoring device (9) is used to detect the composition of flue gas after denitrification reaction in the denitrification reactor; the system also includes a pressure sensor (10), a temperature sensor (11) and a preheater (12), the pressure sensor (10) is used to measure the pressure inside the cylinder (1); the temperature sensor (11) is used to measure the temperature inside the cylinder (1) and the heating component (2); the preheater (12) is located between the mass flow meter (8) and the gas inlet connecting pipe, and the preheater (12) is used to heat the flue gas before denitrification reaction.

2. The low-temperature denitrification catalyst measurement system according to claim 1, characterized in that, An airflow equalization fan (6) is provided on the inner side of the top of the cylinder (1), and the airflow equalization fan (6) is used to perform the first equalization of airflow inside the cylinder (1).

3. The low-temperature denitrification catalyst measurement system according to claim 2, characterized in that, An airflow distribution baffle (7) is provided below the airflow distribution fan (6), and the airflow distribution baffle (7) is located below the gas inlet. The airflow distribution baffle (7) is used to perform a second airflow equalization on the airflow inside the cylinder (1).

4. The low-temperature denitrification catalyst measurement system according to claim 3, characterized in that, The airflow distribution baffle (7) is provided with multiple layers of uniformly sized round holes.

5. The low-temperature denitrification catalyst measurement system according to claim 1, characterized in that, The system also includes a control unit (13) for monitoring and controlling the denitrification reactor, mass flow meter (8), exhaust gas online monitoring device (9), pressure sensor (10), temperature sensor (11) and preheater (12).

6. A method for measuring the low-temperature denitrification catalyst in the system according to any one of claims 1 to 5, characterized in that, The method includes: adjusting the fixed position of the liner (4) on the support rod (3) so that the center position of the catalyst bed (5) above the liner (4) is at the same level as the center of the heating element (2), and adjusting the temperature of the heating element (2) to the catalytic temperature; the ammonia gas and flue gas before denitrification are respectively measured by the mass flow meter (8) and enter the cylinder (1) from the gas inlet, and the ammonia gas and flue gas undergo denitrification reaction with the denitrification catalyst in the catalyst bed (5), and the space velocity of the denitrification reaction is adjusted according to the total flow rate of ammonia gas and flue gas before denitrification and the amount of denitrification catalyst; the flue gas after denitrification is discharged from the gas outlet and enters the tail gas online monitoring device (9), and the composition and content of the flue gas after denitrification are detected by the tail gas online monitoring device (9); the space velocity of the denitrification reaction is adjusted according to the total flow rate of ammonia gas and flue gas before denitrification and the amount of denitrification catalyst.

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