Denitration distribution control system

Abstract

The utility model discloses a denitration distribution control system, and belongs to the technical field of denitration equipment. According to the distribution control system, the buffer tank is arranged on the compressed air pipe network, and the buffer tank is connected with the denitration agent storage tank, so that liquid can be prevented from flowing back to the compressed air pipe network, a manager can be timely warned and notified to handle the liquid, the flowing-back liquid can be automatically recycled into the denitration agent storage tank, a compressed air system is prevented from being polluted, and accidents are avoided; safety, convenience and environmental protection; a large-volume filter is further arranged at the tail end of the liquid path pipeline, impurities in the liquid path are effectively filtered and intercepted, and the risk that the spray gun is blocked is reduced to the maximum extent; the blockage condition of the filter is displayed in the control module through the differential pressure transmitter, when the differential pressure rises, an alarm is automatically given to inform a manager, problems are found and processed in time, and time is saved; meanwhile, a standby filter is also arranged, so that on-line cleaning can be carried out under the condition that the normal operation of the denitration device is not influenced, and the long-period stable operation of the denitration system is ensured.

Description

Technical Field

[0001] The utility model belongs to the technical field of denitration equipment, and particularly relates to a denitration distribution control system. Background Art

[0002] At present, the industrial sources that lead to excessive nitrogen oxides in the atmosphere include: the combustion process of fuels such as coal, oil or natural gas in industries such as petrochemicals, electric power, steel metallurgy, coking, cement and building materials.

[0003] Selective non-catalytic reduction technology (SNCR) is a common denitrification method. It uses ammonia or urea as a denitrification agent, and selectively reacts with NOx to generate N2 and H2O in the temperature range of 850-1100°C without the use of a catalyst. SNCR equipment mainly includes urea solution or ammonia solution storage tank, reagent delivery pump, dilution water tank, water pump, metering equipment, mixer, equalization module, compressed air system, spray gun and control system. Existing SNCR equipment often arranges multiple denitrification spray guns, equipped with an equalization module, and the equalization module contains liquid flow meters, air pressure regulating valves, valves and other components, which can only ensure that the denitrification agent and compressed air of each branch spray gun are evenly distributed; the air compressor or factory compressed air network compresses the air duct directly connected to the gas circuit main pipe of the equalization module; the denitrification agent and dilution water are mixed by the mixer and transported to the liquid circuit main pipe of the equalization module, and the main pipe is equipped with a ball valve or gate valve to control the switch. The mixer and nozzle of the denitrification spray gun often use micropores or slit structures to contact the gas and liquid to achieve the purpose of atomization.

[0004] The existing denitrification dosing system is often equipped with a simple Y-type filter (the mesh size is generally high and difficult to filter effectively) at the inlet of the drug pump and water pump to remove particulate impurities in the process before the pump. However, the long-distance pipeline from the dosing pump outlet to the spray gun is often overlooked. Welding slag, mud, and newly generated rust blocks in the pipeline during use are often easily brought to the end of the process, causing blockage of the nozzle or spray gun mixer and causing pressure buildup in the liquid pipeline.

[0005] At the same time, in coal-fired boilers, the high-temperature coal ash in the furnace can also cause coking blockage in the nozzle, causing pressure buildup in the liquid pipeline. When the pressure at the end of the liquid system is higher than the pressure of the gas system, the liquid will flow back into the air pipeline through the spray gun mixer. The commonly used measure to prevent backflow is to set a one-way valve on the gas pipeline. This method can prevent liquid backflow to a certain extent, but its simple mechanical structure is often difficult to meet complex application scenarios. When the spring system fails, there are particulate impurities in the pipeline, and the liquid pressure is slightly higher than the gas pressure, the anti-return function is prone to failure, and it is impossible to prevent the liquid from flowing back into the gas line, nor can it indirectly display whether the spray gun nozzle is blocked. Utility Model Content

[0006] In view of the above problems, the utility model proposes a denitration distribution control system, including a compressed air duct network, a liquid pipeline, and a distributor module for redistributing the gas in the compressed air duct network and the liquid denitration agent in the liquid pipeline;

[0007] The distributor module includes a buffer tank arranged on the compressed air duct network and a plurality of filters with differential pressure transmitters arranged at the outlet end of the liquid pipeline;

[0008] A liquid level gauge is installed in the buffer tank, the top of the buffer tank is connected to the air outlet of the compressed air duct network, the lower end of the buffer tank is connected to a circulation pipeline, the outlet end of the circulation pipeline leads to a denitrification agent storage tank, and a control valve is arranged on the circulation pipeline;

[0009] The signal transmitting ends of the liquid level meter and the differential pressure transmitter are connected to the receiving end of the control module, and the output end of the control module is connected to the control valve and a plurality of filters.

[0010] Furthermore, the control module controls the opening and closing of the control valve according to the signal of the liquid level meter;

[0011] The control module controls the switching of multiple filters according to the signal of the differential pressure transmitter and sends an alarm message to remind the operator.

[0012] Furthermore, the control module includes a PLC unit and / or a DCS control unit.

[0013] Furthermore, the liquid pipeline is led out from the denitrification agent storage tank, and a dosing pump, a flow meter and an online mixer are sequentially arranged on the liquid pipeline in the direction leading to the distributor module.

[0014] Furthermore, an air inlet valve is arranged on the compressed air duct network, and an outlet end of the air inlet valve is connected to a buffer tank.

[0015] Furthermore, the filter is arranged at the end of the liquid pipeline and before entering the spray gun.

[0016] Furthermore, a transparent window is provided on the tank body of the buffer tank.

[0017] Furthermore, the outlet end of the distributor module is connected to a spray gun.

[0018] Furthermore, the spray gun includes a plurality of spray gun mixers and nozzles.

[0019] Furthermore, the liquid level gauge is provided with a liquid level warning value;

[0020] The differential pressure transmitter is provided with a differential pressure warning value.

[0021] Beneficial effects of the utility model:

[0022] The utility model provides a buffer tank on the compressed air duct network during the denitrification agent addition process, and connects the buffer tank with the denitrification agent storage tank, so as to prevent the liquid from flowing back to the compressed air duct network, and promptly warn the management personnel to handle it, and can also automatically recycle the backflowing liquid to the denitrification agent storage tank, so as to prevent the compressed air system from being polluted and causing accidents, and is safe, convenient and environmentally friendly.

[0023] The utility model also comprehensively considers the sources of impurities in the process, and sets a large-volume filter at the end of the liquid pipeline to effectively filter and intercept impurities in the liquid line, thereby minimizing the risk of spray gun clogging; the filter clogging situation is displayed in the control module through the differential pressure transmitter, and an automatic alarm is triggered to notify management personnel when the differential pressure rises, so that problems can be discovered and dealt with in time, saving time; at the same time, a spare filter is also provided, which can perform online cleaning without affecting the normal operation of the denitrification device, thereby ensuring the long-term stable operation of the denitrification system.

[0024] Other features and advantages of the utility model will be described in the following description, and partly become apparent from the description, or understood by implementing the utility model. The purpose and other advantages of the utility model can be realized and obtained by the structures indicated in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 An exemplary schematic diagram of the denitration distribution control system proposed by the utility model is shown;

[0027] Figure 2 Another exemplary schematic diagram of the denitration distribution control system proposed by the utility model is shown;

[0028] In the figure, 1. denitrification agent storage tank; 2. liquid pipeline; 3. dosing pump; 4. flow meter; 5. online mixer; 6. compressed air duct network; 7. air inlet valve; 8. distributor module; 9. buffer tank; 10. liquid level meter; 11. control valve; 12. PLC unit; 13. filter; 14. differential pressure transmitter; 15. spray gun mixer; 16. nozzle; 17. boiler; 18. DCS control unit. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solution and advantages of the embodiment of the utility model clearer, the technical solution in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiment of the utility model. Obviously, the described embodiment is a part of the embodiment of the utility model, not all of the embodiments. Based on the embodiment of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0030] The utility model proposes a denitrification distribution control system, such as Figure 1 As shown, it includes a compressed air duct network 6 for conveying gas, a liquid pipeline 2 for conveying liquid denitrification agent, and a distributor module 8 for redistributing the gas in the compressed air duct network 6 and the liquid denitrification agent in the liquid pipeline 2, and the outlet end of the distributor module 8 is connected to a spray gun.

[0031] The liquid pipeline 2 is led out from the denitrification agent storage tank 1 , and a dosing pump 3 , a flow meter 4 and an online mixer 5 are sequentially arranged on the liquid pipeline 2 along the pipeline leading to the distributor module 8 .

[0032] The compressed air duct network 6 introduces compressed air from the air source pipeline, and an air inlet valve 7 is arranged on the compressed air duct network 6 to control the entry of compressed air.

[0033] The distributor module 8 includes a buffer tank 9 connected to the outlet end of the air inlet valve 7. The buffer tank 9 is arranged on the compressed air duct network 6 to receive the liquid that flows back to the compressed air duct network 6. The lower end of the buffer tank 9 is connected to the circulation pipeline. The outlet end of the circulation pipeline leads to the denitrification agent storage tank 1. A control valve 11 is arranged on the circulation pipeline to control the release of the liquid in the buffer tank 9. A liquid level meter 10 is installed in the buffer tank 9 to measure the position of the liquid in the buffer tank 9. The liquid level meter 10 is connected to a control module. The control module is used to obtain the liquid level data signal on the liquid level meter 10 for analysis. The control module includes a PLC unit 12 and / or a DCS control unit 18.

[0034] The distributor module 8 also includes a filter 13 with a differential pressure transmitter 14 at the end of the liquid pipeline 2. The filter 13 is arranged at the end of the liquid pipeline 2 and before entering the spray gun. The differential pressure transmitter 14 is connected to the control module signal. In this embodiment, two filters 13 can be set, one for use and one for backup. Impurities in the liquid pipeline 2 will be fully intercepted before entering the spray gun. If too many impurities are intercepted in one of the filters 13, the differential pressure transmitter 14 measures the pressure increase of the denitrification liquid in the liquid pipeline 2, and transmits the measurement data signal to the control module. If the measurement data exceeds the set pressure difference warning value, an alarm is triggered and the operator is notified, and the filter 13 is switched to the backup filter 13, which can ensure that the denitrification dosing is continuous.

[0035] In other embodiments of the present invention, the filter 13 may be equipped with a cleaning unit to regularly clean the filter screen of the filter 13 .

[0036] In one embodiment of the present invention, the control module is composed of a PLC unit 12 and a DCS control unit 18, as shown in FIG. Figure 1-2 As shown, the level meter 10 is connected to the PLC unit 12 by signal, and the differential pressure transmitter 14 can be directly or indirectly connected to the DCS control unit 18 by signal, and the DCS control unit 18 controls the switch of the control valve 11 according to the analysis of the liquid level data. When the DCS control unit 18 is set, the measurement data signal of the level meter 10 is first transmitted to the PLC unit 12, and then transmitted to the DCS control unit 18 through the PLC unit 12, and the DCS control unit 18 controls the switch of the control valve 11; similarly, the measurement data signal of the differential pressure transmitter 14 is also transmitted to the DCS control unit 18, and the DCS control unit 18 controls the switching state of the filter 13.

[0037] In another embodiment of the utility model, the control module can use an independent PLC unit 12 to uniformly analyze and control the data of the differential pressure transmitter 14 and the data of the liquid level meter 10 (not shown in the figure). In the specific implementation process, the data transmitted by the liquid level meter 10 can be recorded as the first data, and the data transmitted by the differential pressure transmitter 14 can be recorded as the second data. The opening and closing of the control valve 11 is controlled according to whether the first data exceeds the liquid level setting value. If the liquid level setting value is exceeded, the control valve 11 is opened to release the liquid in the buffer tank 9 to the denitrification agent storage tank; according to whether the second data exceeds the differential pressure setting value, it is determined whether to enable the spare filter 13. If the differential pressure setting value is exceeded, the spare filter 13 is enabled, and the operator is promptly notified to clean the clogged filter 13. Similarly, in other embodiments, the PLC unit 12 may not be set, and only a single DCS control unit 18 is set to control the opening and closing of the control valve 11 and the switching of multiple filters 13.

[0038] In one embodiment of the utility model, a transparent window is provided on the tank body of the buffer tank 9, so that the management personnel can observe the liquid level in the buffer tank 9 on site. The liquid level meter 10 can realize long-distance liquid level transmission, which is convenient for the control module to obtain and display data. When the liquid denitrification agent in the liquid pipeline 2 is backflowing into the compressed air duct network 6, the liquid level in the buffer tank 9 rises, and the measurement data signal of the liquid level meter 10 is transmitted to the control module. The control module determines whether to trigger the alarm signal according to the signal value. If triggered, the operator is notified to check the spray gun and trigger the control valve 11 switch to perform automatic liquid discharge operation. The automatic liquid discharge operation can be set in advance according to the actual situation. For example, when the liquid level in the buffer tank 9 exceeds the liquid level warning value, such as 50% of the volume of the buffer tank 9, the control valve 11 automatically opens to discharge the liquid. When the liquid level drops to 0, the control valve 11 automatically closes, and the backflow liquid is automatically recovered to the denitrification agent storage tank 1. The type of the liquid level meter 10 is not specifically limited in the present invention, and it can be a magnetic flap liquid level meter, a float liquid level meter, a immersion liquid level meter, a radar liquid level meter, an ultrasonic liquid level meter, a magnetostrictive liquid level meter, etc., as long as it can measure the liquid position in the buffer tank 9.

[0039] The spray gun includes a plurality of spray gun mixers 15 and nozzles 16. The spray gun mixers 15 are used to mix the air in the compressed air duct network 6 and the denitrification liquid in the liquid pipeline 2. The mixed denitrification agent is sprayed into the boiler 17 through the nozzles 16 to treat the nitrogen oxides in the boiler 17. The utility model does not limit the number of flow paths of the spray gun mixer 15. Figure 2 As shown, the spray gun mixer 15 is provided with two flow paths, and may also be provided with four flow paths.

[0040] The denitrification spray gun dosing device proposed by the utility model can also perform pipeline flushing after the initial use or long-term shutdown, or replace and clean the materials in the pipeline before the system is shut down. During the specific implementation, the gas-liquid pipeline of the spray gun mixer 15 is connected, the air inlet valve 7 is closed, the control valve 11 is opened, and the whole process is connected through the buffer tank 9; before the system is shut down, the residual materials in the pipeline are replaced and cleaned, and the internal waste liquid of the entire dosing device is returned to the denitrification agent storage tank 1 for collection, which is convenient for recycling and avoids waste and pollution of the environment; after the initial use or long-term shutdown, the whole process is circulated and flushed, and the impurities in the dosing device are brought to the filter 13 to the maximum extent, and cleaned uniformly to avoid clogging of the spray gun after formal use.

[0041] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A denitrification distribution control system, It is characterized in that It comprises a compressed air duct network (6), a liquid pipeline (2), and a distributor module (8) for redistributing the gas in the compressed air duct network (6) and the liquid denitrifying agent in the liquid pipeline (2); The distributor module (8) comprises a buffer tank (9) arranged on the compressed air duct network (6) and a plurality of filters (13) with differential pressure transmitters (14) arranged at the outlet end of the liquid pipeline (2); A liquid level meter (10) is installed in the buffer tank (9), the top of the buffer tank (9) is connected to the air outlet end of the compressed air duct network (6), the lower end of the buffer tank (9) is connected to a circulation pipeline, the outlet end of the circulation pipeline leads to the denitrification agent storage tank (1), and a control valve (11) is provided on the circulation pipeline; The signal transmitting ends of the liquid level meter (10) and the differential pressure transmitter (14) are connected to the receiving end of the control module, and the output end of the control module is connected to the control valve (11) and a plurality of filters (13).

2. The denitration distribution control system according to claim 1, It is characterized in that The control module controls the opening and closing of the control valve (11) according to the signal of the liquid level meter (10); The control module controls the switching of the plurality of filters (13) according to the signal of the differential pressure transmitter (14) and sends an alarm message to remind the operator.

3. The denitration distribution control system according to claim 1, It is characterized in that The control module is a PLC unit (12) and / or a DCS control unit (18).

4. The denitration distribution control system according to claim 1, It is characterized in that The liquid pipeline (2) is led out from the denitrification agent storage tank (1), and a dosing pump (3), a flow meter (4) and an online mixer (5) are sequentially arranged on the liquid pipeline (2) in the direction leading to the distributor module (8).

5. The denitration distribution control system according to claim 1, It is characterized in that An air inlet valve (7) is provided on the compressed air pipe network (6), and the outlet end of the air inlet valve (7) is connected to a buffer tank (9).

6. The denitration distribution control system according to claim 1, It is characterized in that The filter (13) is arranged at the end of the liquid pipeline (2) and before entering the spray gun.

7. The denitration distribution control system according to any one of claims 1 to 6, It is characterized in that A transparent window is provided on the tank body of the buffer tank (9).

8. The denitration distribution control system according to any one of claims 1 to 6, It is characterized in that The outlet end of the distributor module (8) is connected to a spray gun.

9. The denitration distribution control system according to claim 8, It is characterized in that The spray gun comprises a plurality of spray gun mixers (15) and nozzles (16).

10. The denitration distribution control system according to any one of claims 1 to 6, It is characterized in that The liquid level meter (10) is provided with a liquid level warning value; The differential pressure transmitter (14) is provided with a differential pressure warning value.

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