CN216321047U - SNCR + SCR coupling deNOx systems based on high low temperature flue gas mixes - Google Patents
SNCR + SCR coupling deNOx systems based on high low temperature flue gas mixes Download PDFInfo
- Publication number
- CN216321047U CN216321047U CN202120716496.8U CN202120716496U CN216321047U CN 216321047 U CN216321047 U CN 216321047U CN 202120716496 U CN202120716496 U CN 202120716496U CN 216321047 U CN216321047 U CN 216321047U
- Authority
- CN
- China
- Prior art keywords
- urea solution
- outlet
- scr
- sncr
- metering
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Landscapes
- Treating Waste Gases (AREA)
Abstract
A SNCR + SCR coupling deNOx systems based on high low temperature flue gas mixes includes: a urea solution preparing and storing device for preparing and storing a urea solution; the urea solution circulating device is connected with the outlet of the urea solution preparing and storing device; the inlet of the metering and distributing device is connected with the outlet of the urea solution circulating device, and the outlet of the metering and distributing device is divided into two paths; the inlet of the SNCR urea solution injection device is connected with one path of the outlet of the metering and distributing device, and the outlet is arranged in the hearth of the coal-fired boiler; the inlet of the SCR urea solution injection device is connected with the other path of the outlet of the metering and distributing device, and the outlet of the SCR urea solution injection device is arranged at the outlet of the high-temperature flue of the coal-fired boiler; the SCR reactor is connected with a high-temperature flue of the coal-fired boiler, and the SCR urea solution injection device is positioned in front of the SCR reactor along the flow direction of flue gas. The utility model can prevent the corrosion of the heat exchange surface of the boiler, improve the denitration efficiency, reduce the escape of ammonia and adapt to the full-load working condition of the boiler.
Description
Technical Field
The utility model belongs to the technical field of industrial denitration, and particularly relates to an SNCR + SCR coupling denitration system based on high-low temperature flue gas mixing.
Background
Coal combustion discharges a large amount of NOXTherefore, the technical improvement of denitration of the coal industrial boiler is inevitable. At present, denitration technologies with more applications mainly comprise a selective catalytic reduction method (SCR), a selective non-catalytic reduction method (SNCR) and a SNCR + SCR denitration technology coupled with the selective non-catalytic reduction method (SNCR). The SCR technology is to use a denitration catalyst to remove NO at the temperature of 300-400 DEG CXReduction to N2And H2O, has been widely applied in the world, especially in developed countries, but has higher process investment and operation cost and is difficult to popularize in small and medium-sized domestic enterprises. The SNCR technology is also called thermal denitration, and NO is realized by uniformly spraying a reducing agent in a high-temperature region (800-1100 ℃) of a hearthXAnd (4) removing. The process is suitable for the transformation of small and medium boilers, the investment cost is low, the ammonia escape is high, and the denitration efficiency is low. The SNCR + SCR coupling denitration combines two process characteristics of SCR and SNCR, and the SNCR technology is adopted to remove most NO at the front section of the denitration processXAnd a small amount of SCR catalyst is needed at the tail part of the denitration process to ensure that NO in the smoke can be containedXDischarging after reaching the standard. The process is suitable for the transformation of boilers which are limited by space and can not be added with a large amount of catalyst, and compared with the SCR technology, the process has higher acquisitionThe investment and the operation cost of the denitration efficiency are reduced.
The SNCR + SCR coupling technology has two reaction zones, and the reducing agent is first sprayed into the hearth of the first reaction zone via the spraying system on the boiler wall to collect NO in the reducing agent and fume at high temperatureXNon-catalytic reduction reaction is carried out to realize preliminary denitrification. Then, the unreacted reducing agent enters a second reaction zone SCR reactor of the coupling process to further denitrate. The SNCR + SCR coupling denitration process is a mixing process which effectively combines the low cost characteristic of the SNCR process with the high efficiency of the SCR process and makes the best of the advantages and disadvantages. The arrangement of the boiler tail flue is very tight, the conventional ammonia injection grid cannot be arranged, and the SNCR + SCR coupling method is suitable.
SNCR + SCR denitration technology requires injected ammonia and NO in flue gas in order to obtain efficient denitration reactionXHas good contact and forms a uniformly distributed flow field, a temperature field and a concentration field. In a single SCR denitration technology, a complex Ammonia Injection Grid (AIG) and a control system are required to be arranged, and measures such as arranging mixing facilities at multiple positions, lengthening a flue to ensure that the AIG is far enough away from a catalyst and the like are required. And the reducing agent arrangement injection system of the coupling technology is arranged on the boiler wall and is far away from the downstream SCR reactor. Therefore, good mixing and distribution of the reducing agent and the NOx can be obtained at the catalyst reaction inlet without additionally arranging a mixing facility or lengthening a flue. However, a great deal of facts show that the reducing agent sprayed in the SNCR denitration has chemical corrosion and electrochemical corrosion effects on the heat exchange surface of the boiler, leakage of the heat exchange surface of the boiler is caused, the tension situation of passive furnace shutdown is caused, and the safe production is seriously influenced.
Disclosure of Invention
In order to solve the problems that the existing SNCR + SCR coupled denitration system corrodes a heat exchange surface of a boiler and the like, the utility model aims to provide the SNCR + SCR coupled denitration system based on high-low temperature flue gas mixing, and the SNCR + SCR coupled denitration system can further improve the denitration efficiency, reduce ammonia escape and adapt to the full-load working condition of the boiler.
In order to achieve the purpose, the utility model adopts the technical scheme that:
a SNCR + SCR coupling deNOx systems based on high low temperature flue gas mixes includes:
a urea solution preparing and storing device for preparing and storing a urea solution;
the urea solution circulating device 7 is connected with the outlet of the urea solution preparing and storing device;
the inlet of the metering and distributing device 3 is connected with the outlet of the urea solution circulating device 7, and the outlet is divided into two paths;
an inlet of the SNCR urea solution injection device 8 is connected with one way of an outlet of the metering and distributing device 3, and an outlet is arranged in a hearth of the coal-fired boiler 9;
the inlet of the SCR urea solution injection device 10 is connected with the other path of the outlet of the metering and distributing device 3, and the outlet is arranged at the outlet of the high-temperature flue of the coal-fired boiler 9;
and the SCR reactor 11 is connected with a high-temperature flue of the coal-fired boiler 9, and the SCR urea solution injection device 10 is positioned in front of the SCR reactor 11 along the flow direction of flue gas.
Further, the urea solution preparation and storage device comprises:
the inlet of the urea dissolving tank 5 is connected with the urea particle storage tank 4 and the water storage tank, the outlet of the urea dissolving tank is connected with the urea solution storage tank 6, the outlet of the urea solution storage tank 6 is connected with the urea solution circulating device 7, the outlet of the urea solution circulating device 7 is divided into two paths, one path is connected with the inlet of the metering and distributing device 3, and the other path is connected with the urea solution storage tank 6 in a return mode.
Further, the urea solution storage tank 6 is provided with a heating device for maintaining the temperature of the urea solution higher than the crystallization temperature corresponding to the configured concentration by more than 20 ℃.
Further, the urea solution circulating device 7 comprises a centrifugal pump with a frequency converter, a back pressure valve is installed at the outlet of the pump, and a pressure gauge, a temperature gauge and a flow meter are arranged on a pipeline.
Further, the metering and distributing device 3 is a metering and distributing cabinet.
Further, an air compressor 1 is connected to the metering and dispensing device 3.
Further, the metering and distributing devices 3 are arranged in one-to-one correspondence with the coal-fired boilers 9.
Further, the metering and distributing device 3 is connected with an outlet of the water pump 2, and an inlet of the water pump 2 is connected with the saline water.
Further, the SNCR urea solution injection device 8 is a single double-fluid spray gun, and the temperature range of the outlet of the SNCR urea solution injection device corresponding to the hearth is 800-1100 ℃; the SCR urea solution injection device 10 is two double-fluid spray guns, and the temperature range of the outlets of the two double-fluid spray guns, which corresponds to the outlet of the high-temperature flue, is 350-600 ℃.
Furthermore, the single double-fluid spray gun is inclined downwards, and the included angle between the single double-fluid spray gun and the water-cooled wall of the hearth is 5 degrees.
Compared with the prior art, the utility model has the beneficial effects that:
1. the corrosion of the heat exchange surface of the boiler can be avoided.
2. The denitration efficiency can be further improved.
3. Ammonia slip can be further reduced.
4. Can adapt to the full load working condition of the boiler.
Drawings
FIG. 1 is a schematic diagram of the present invention.
Detailed Description
The embodiments of the present invention will be described in detail below with reference to the drawings and examples.
As shown in fig. 1, the utility model relates to an SNCR + SCR coupled denitration system based on high and low temperature flue gas mixing, which mainly comprises: a urea solution preparation and storage device, a urea solution circulating device 7, a metering and distributing device 3, an SNCR urea solution injection device 8, an SCR urea solution injection device 10, an SCR reactor 11 and the like.
Wherein:
the urea solution preparation and storage device is mainly used for preparing and storing urea solution, and can comprise a urea dissolving tank 5 and a urea solution storage tank 6, and can also combine the dissolving and the storage into a tank body. The urea particle storage tank 4 and the water storage tank are respectively connected with a urea dissolving tank 5 to provide urea particles and water, the urea solution obtained by dissolving is sent to a urea solution storage tank 6 to be stored for later use, and the mass concentration of the solution is generally 50%. The urea solution storage tank 6 can be additionally provided with heating equipment to maintain the temperature of the urea solution higher than the crystallization temperature corresponding to the configured concentration by more than 20 ℃.
The urea solution circulating device 7 is mainly used for conveying the stored urea solution to the metering and distributing device 3, a centrifugal pump can be used as main equipment, a main frequency converter and a standby frequency converter are arranged, a back pressure valve can be installed at the outlet of the pump to protect a pipeline, and a pressure gauge, a temperature gauge, a flow meter and the like for remote control and detection can be arranged on the pipeline. In summary, the urea solution circulation device 7 is a conventional device for circulating and conveying the solution. It can also be added with a reflux function, namely the outlet of the urea solution circulating device 7 is divided into two paths, one path is connected with the inlet of the metering and distributing device 3, and the other path is connected with the urea solution storage tank 6.
The metering and distributing device 3 is mainly used for distributing the urea solution according to the flow rate, and the outlet of the metering and distributing device is correspondingly divided into two paths. In a specific project, the metering and distributing device 3 can adopt a metering and distributing cabinet to carry out modular design and adopt a PLC for control. The metering and dispensing device 3 can be connected to an air compressor 1 for spraying the urea solution in atomized form. The water pump 2 can also be connected, the water pump 2 can provide saline water, and the pipeline is flushed when the machine is stopped, so that the urea solution is prevented from crystallizing. Moreover, the metering and distributing devices 3 and the coal-fired boilers 9 are preferably arranged in one-to-one correspondence, that is, one set of metering and distributing device 3 is configured for each coal-fired boiler 9 so as to accurately control the flow rate of each urea solution injection device and calculate the flow rate and pressure of the atomized air.
The SNCR urea solution injection device 8 is mainly used for injecting one path of urea solution provided by the metering and distributing device 3 to the hearth of the coal-fired boiler 9, and can adopt a single double-fluid spray gun to be installed on a proper position (the temperature is in the range of 800-1100 ℃) of the boiler wall through a hole. The included angle between the spray gun and the water-cooled wall can be changed, so that the spray gun is inclined downwards by 5 degrees, and meanwhile, the depth of the spray gun and the hearth is increased under the condition that the spray gun is not burnt out. The urea solution is generally sprayed in an atomized form, and the atomization device can be realized by the air compressor 1, or by arranging an air pump at the SNCR urea solution spraying device 8, and the like. In order to carry out automatic control, the two-fluid spray gun can be provided with compressed air protection, and when the compressed air pressure of the spray gun is lower than 0.4MPa, the urea solution electric main valve is automatically closed, and the SNCR denitration operation is quitted.
The SCR urea solution injection device 10 is mainly used for injecting another path of urea solution provided by the metering and distributing device 3 at the outlet of the high-temperature flue of the coal-fired boiler 9, two double-fluid spray guns can be adopted, the temperature range of the outlet corresponding to the outlet of the high-temperature flue is 350-600 ℃, and the urea solution is rapidly decomposed into NH at the temperature3Enters the SCR reactor 11 along with the flue gas and continues to react with the residual NO under the action of the catalystXReact to further reduce NOXAnd (4) discharging the amount. In order to avoid the corrosion of the urea solution to the heating surface of the boiler, the SCR urea solution injection device 10 is suitable for full-scale operation.
The urea solution is generally sprayed in an atomized form, and the atomization device can be realized by the air compressor 1, or by arranging an air pump at the SCR urea solution spraying device 10.
The SCR reactor 11 is an existing device, and is connected to a high-temperature flue of the coal-fired boiler 9 in an existing manner, and is located behind the SCR urea solution injection device 10 in the flow direction of flue gas, and an air preheater or an economizer 12 may be provided behind the SCR urea solution injection device.
Based on the structure, the working process and the principle of the utility model are as follows:
firstly, dissolving urea granules into a urea solution with the mass fraction of 50% and storing for later use.
Secondly, pressurizing and conveying the urea solution to the metering and distributing device 3 through the urea solution circulating device 7;
then, the distributed urea solution is respectively and accurately sprayed into a hearth and a high-temperature flue outlet in forms of atomization and the like under the action of compressed air, and NO in the flue gasXAnd reacting to realize the aim of denitration.
The utility model is very suitable for boilers without reserving the installation space of the SCR reactor for the old boilers. The SNCR is utilized to carry out preliminary denitration in the earlier stage in the boiler, the demand of the catalyst is reduced, and the urea injection point is additionally arranged at the high-temperature flue gas outlet, so that the long-term corrosion and pipe explosion of the urea solution to the heat exchange surface of the boiler are avoided and reduced.
Claims (8)
1. The utility model provides a SNCR + SCR coupling deNOx systems based on high low temperature flue gas mixes which characterized in that includes:
a urea solution preparing and storing device for preparing and storing a urea solution;
a urea solution circulating device (7) connected with the outlet of the urea solution preparing and storing device;
the inlet of the metering and distributing device (3) is connected with the outlet of the urea solution circulating device (7), and the outlet is divided into two paths;
an inlet of the SNCR urea solution injection device (8) is connected with one way of an outlet of the metering and distributing device (3), and an outlet is arranged in a hearth of the coal-fired boiler (9);
the inlet of the SCR urea solution injection device (10) is connected with the other path of the outlet of the metering and distributing device (3), and the outlet is arranged at the outlet of the high-temperature flue of the coal-fired boiler (9);
the SCR reactor (11) is connected with a high-temperature flue of the coal-fired boiler (9), and the SCR urea solution injection device (10) is positioned in front of the SCR reactor (11) along the flow direction of flue gas;
the outlet of the water pump (2) is connected with the metering and distributing device (3), and the inlet of the water pump (2) is connected with the saline water;
the SNCR urea solution injection device (8) is a single double-fluid spray gun; the SCR urea solution injection device (10) is two double-fluid spray guns.
2. The SNCR + SCR coupled denitration system based on high-low temperature flue gas mixing of claim 1, wherein the urea solution preparation and storage device comprises:
the urea dissolving tank (5) is connected with the urea particle storage tank (4) and the water storage tank at the inlet, connected with the urea solution storage tank (6) at the outlet, connected with the urea solution circulating device (7) at the outlet of the urea solution storage tank (6), the outlet of the urea solution circulating device (7) is divided into two paths, one path is connected with the inlet of the metering and distributing device (3), and the other path is connected with the urea solution storage tank (6) in a return mode.
3. The SNCR + SCR coupled denitration system based on high-low temperature flue gas mixing as claimed in claim 2, wherein the urea solution storage tank (6) is configured with a heating device.
4. The SNCR + SCR coupled denitration system based on high-low temperature flue gas mixing as recited in claim 1, wherein the urea solution circulating device (7) comprises a centrifugal pump with a frequency converter, a back pressure valve is installed at the outlet of the pump, and a pressure gauge, a temperature gauge and a flow meter are arranged on the pipeline.
5. The SNCR + SCR coupled denitration system based on high-low temperature flue gas mixing of claim 1, wherein the metering and distributing device (3) is a metering and distributing cabinet.
6. The SNCR + SCR coupled denitration system based on high and low temperature flue gas mixing according to claim 1 or 5, characterized in that an air compressor (1) is connected to the metering and distributing device (3).
7. The SNCR + SCR coupled denitration system based on high-low temperature flue gas mixing according to claim 1 or 5, wherein the metering and distributing devices (3) are arranged in one-to-one correspondence with the coal-fired boilers (9).
8. The SNCR + SCR coupled denitration system based on high-low temperature flue gas mixing of claim 1, wherein the angle between the downward inclination of the single two-fluid spray gun and the water wall of the hearth is 5 degrees.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202120716496.8U CN216321047U (en) | 2021-04-08 | 2021-04-08 | SNCR + SCR coupling deNOx systems based on high low temperature flue gas mixes |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202120716496.8U CN216321047U (en) | 2021-04-08 | 2021-04-08 | SNCR + SCR coupling deNOx systems based on high low temperature flue gas mixes |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN216321047U true CN216321047U (en) | 2022-04-19 |
Family
ID=81128696
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202120716496.8U Active CN216321047U (en) | 2021-04-08 | 2021-04-08 | SNCR + SCR coupling deNOx systems based on high low temperature flue gas mixes |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN216321047U (en) |
-
2021
- 2021-04-08 CN CN202120716496.8U patent/CN216321047U/en active Active
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| WO2021184786A1 (en) | Urea direct-injection pyrolysis denitrification device arranged inside outlet flue duct of gas turbine | |
| CN205235766U (en) | Automatic control SCR flue gas denitration urea pyrolysis system | |
| CN113426296A (en) | Energy-saving urea hydrolysis ammonia preparation denitrification facility based on combustion engine SCR denitration | |
| CN203316010U (en) | Flue gas denitration system with SCR and SNCR coupled | |
| CN211799959U (en) | Ammonia SNCR (Selective non catalytic reduction) denitration system for tower boiler | |
| CN207680335U (en) | A kind of waste incinerator flue denitrating system | |
| CN207025089U (en) | A kind of ammonia system processed that urea pyrolysis is directly realized using high temperature flue-gas from boiler | |
| CN216321047U (en) | SNCR + SCR coupling deNOx systems based on high low temperature flue gas mixes | |
| CN104941446A (en) | Ammonia spraying grating anti-blocking device for SCR denitration system | |
| CN205216547U (en) | Flue gas denitration process systems | |
| CN209828701U (en) | Preparation facilities of mixed denitrifier based on aqueous ammonia + hydrazine | |
| CN112240560A (en) | Energy-saving SNCR (selective non-catalytic reduction) denitration device and denitration method | |
| CN211896058U (en) | Urea pyrolysis system | |
| CN216395900U (en) | Energy-saving urea hydrolysis ammonia preparation denitrification facility based on combustion engine SCR denitration | |
| CN212758047U (en) | Flue gas denitration system of air gas preheating steel rolling heating furnace | |
| CN210332238U (en) | Three-section type ammonia denitration system by urea pyrolysis | |
| CN212142070U (en) | Ammonia gas uniform distributor for SNCR denitration process | |
| WO2021143933A1 (en) | Denitration method in alkali recovery furnace | |
| CN205627607U (en) | Modified SNCR denitrification facility of medium temperature high efficiency of gratefiring boiler | |
| CN204973512U (en) | Improved generation SNCR+ ozone flue gas denitration device | |
| CN105214494B (en) | The adjustment method of fired power generating unit SCR denitration system | |
| CN107020008A (en) | A kind of CFBB denitrating system and method | |
| CN204768279U (en) | A ammonia injection grid prevents stifled device for SCR deNOx systems | |
| CN210495888U (en) | Be applied to aqueous ammonia diluting device of boiler SNCR denitration | |
| CN205461764U (en) | Novel little spray gun SNCR+ ozone flue gas denitration device |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| GR01 | Patent grant |