CN217082539U - Flue gas recirculation system for biomass CFB boiler - Google Patents
Flue gas recirculation system for biomass CFB boiler Download PDFInfo
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- CN217082539U CN217082539U CN202220577216.4U CN202220577216U CN217082539U CN 217082539 U CN217082539 U CN 217082539U CN 202220577216 U CN202220577216 U CN 202220577216U CN 217082539 U CN217082539 U CN 217082539U
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Abstract
The utility model relates to a flue gas recirculation system for living beings CFB boiler. At present, excess reducing agent of SNCR is used for reduction reaction at a catalyst, and the NOx emission value is further reduced to realize ultra-low emission, but the scheme for reducing NOx can greatly improve the manufacturing cost and the running cost of a boiler. A flue gas recirculation system for a biomass CFB boiler comprising: the device comprises a flue gas recirculation fan (1), a recirculation fan outlet flow device (7), a recirculation fan inlet pressure measuring device (4) and a recirculation fan outlet pressure measuring device (5), wherein the flue gas recirculation fan is respectively connected with a recirculation fan inlet adjusting baffle (2) and a recirculation fan outlet adjusting baffle (3), the recirculation fan inlet adjusting baffle is connected with the recirculation fan inlet pressure measuring device, and the recirculation fan outlet adjusting baffle is connected with a recirculation fan outlet thermocouple (6). The utility model discloses be applied to the boiler field.
Description
Technical Field
The utility model relates to a flue gas recirculation system for living beings CFB boiler.
Background
The development of national energy reform and the improvement of environmental protection requirements, and the utilization of biomass resources become hot spots in the power industry. The biomass fuel has special components, has the fuel characteristics of high moisture, high volatile matter and low calorific value, and the Cl content of yellow straws represented by rice and wheat in the biomass fuel is extremely high, so that different levels of heating surfaces of the boiler are corroded to different degrees. Meanwhile, the ash content of the biomass is high, such as K, Na, alkali metal content in the ash content is high, the melting temperature of the ash is reduced, the boiler is easy to stain and agglomerate, and in order to prevent the problems, the combustion temperature of a hearth of the biomass direct-fired CFB boiler needs to be controlled, and the hearth bed temperature is about 800 ℃ generally at full load. Aiming at the characteristics of biomass fuel, various measures for reducing NOx are adopted, optimization is carried out on design, and the original NOx emission concentration of a biomass direct-fired CFB boiler can be controlled at 100mg/Nm 3 The following.
Because of the existence of CFB boiler cyclone, can make the urea of spouting in the cyclone and flue gas intensive mixing, the at utmost improves denitration efficiency, and fluidized bed boiler's SNCR denitration efficiency can reach about 50~80%, so, usually adopt the SNCR denitration mode when realizing CFB boiler ultralow emission.
At present, the technology of a biomass direct-fired CFB boiler is mature and is widely applied at home and abroad, and the main design parameters are as follows: the hearth bed temperature is about 800 ℃ when the boiler is fully loaded, and the original NOx emission concentration is not higher than 100mg/Nm 3 And in order to realize ultra-low emission, an SNCR denitration device is arranged at the outlet of the boiler furnace. Boiler furnaceThe bed temperature, the furnace outlet flue gas temperature and the original NOx emission value of the boiler are reduced along with the reduction of the load, when the load of the boiler is reduced to 70 percent of BMCR load or below, because the furnace outlet flue gas temperature of the boiler is reduced by a large extent, the flue gas temperature is too low, the denitration reaction efficiency is reduced quickly, and the reduction of the original NOx emission value is relatively small, the NOx emission value cannot meet the requirement of ultralow emission after the load of the boiler is lower than 70 percent of BMCR. In order to enable the NOx emission value of the boiler to meet the requirement of ultralow emission, a layer of denitration catalyst is additionally arranged in a flue at the tail part of the boiler, excess reducing agent of SNCR is used for carrying out reduction reaction at the catalyst, and the NOx emission value is further reduced to realize ultralow emission.
Disclosure of Invention
The utility model aims at providing a flue gas recirculation system for living beings CFB boiler. According to the existing biomass direct-fired CFB boiler and the SNCR denitration scheme thereof, the scheme for reducing the NOx emission value of the biomass direct-fired CFB boiler is optimally designed, the original NOx emission value of the boiler is further reduced, and the flue gas recirculation system for the biomass CFB boiler is provided.
The above purpose is realized by the following technical scheme:
a flue gas recirculation system for a biomass CFB boiler comprising: the device comprises a flue gas recirculation fan, a recirculation fan outlet flow device, a recirculation fan inlet pressure measuring device and a recirculation fan outlet pressure measuring device, wherein the flue gas recirculation fan is respectively connected with a recirculation fan inlet adjusting baffle and a recirculation fan outlet adjusting baffle;
the flue gas recirculation bypass system is formed by a series structure of the flue gas recirculation fan, the inlet adjusting baffle of the recirculation fan, the outlet adjusting baffle of the recirculation fan, the inlet pressure measuring device of the recirculation fan, the outlet thermocouple of the recirculation fan and the outlet flow device of the recirculation fan.
The flue gas recirculation system for the biomass CFB boiler is characterized in that the flue gas recirculation bypass system is respectively connected with a chimney, an induced draft fan and a primary air fan;
the induced draft fan is connected with a dust remover, and the dust remover is connected with an air preheater;
the primary air fan is connected with the air preheater.
The utility model has the advantages that:
1. the utility model discloses the target of original NOx emission value when having reached and having reduced living beings direct combustion circulating fluidized bed boiler 30% and following ultra-low load operation to through the integration application with SNCR denitration technique, when finally having realized living beings direct combustion circulating fluidized bed boiler full load operation, NOx emission value reaches the requirement of ultralow emission, makes living beings direct combustion circulating fluidized bed boiler get the overall scheme more perfect, the performance index is more excellent, has improved living beings direct combustion circulating fluidized bed boiler's market competitiveness.
2. The utility model discloses flue gas recirculation system's principle does: the reduction of the original NOx emission value of the low load of the boiler is realized by reducing the oxygen content in the flue gas when the boiler is in the low load state. The scheme of the flue gas recirculation method is realized by utilizing a flue gas recirculation fan to extract part of boiler flue gas from a dust remover, then the extracted part of boiler flue gas is sent into an inlet of a primary air fan of the boiler, and the extracted part of boiler flue gas is mixed with cold primary air and then enters a primary air system of the boiler to form flue gas recirculation. The excess air coefficient of the boiler is adjusted by adjusting the circulating flue gas amount of the flue gas recirculation system, the recirculated flue gas amount is improved along with the reduction of the boiler load, and the excess air amount of a hearth is ensured to be constant when the boiler is under low load, namely the excess air coefficient is constant.
3. The utility model discloses the smoke outlet position is taken from the draught fan export, and the ash content is very low, has avoided the wearing and tearing of ash particle to the cigarette fan again in the flue gas. The single furnace adopts 1 fan, the model selection of the single fan adopts 10 percent of flue gas recirculation quantity, and the flue gas is introduced into the inlet of a primary fan of the boiler.
4. The utility model provides a problem that NOx discharges and exceeds standard when traditional living beings CFB boiler 30% reaches following ultralow load operation, successfully developed the flue gas recirculation system who is used for living beings direct combustion circulating fluidized bed boiler. The boiler suitable for the project is an ultrahigh pressure biomass direct-fired circulating fluidized bed boiler with ultrahigh pressure parameters, a single intermediate reheating natural circulation drum boiler, balanced ventilation, close arrangement, solid-state slag discharge and a full steel frame suspension structure, and the oxygen content of smoke in a hearth when the biomass direct-fired CFB boiler is operated at low load is reduced, so that the emission value of original NOX of the biomass direct-fired CFB boiler is reduced.
Description of the drawings:
fig. 1 is a schematic structural diagram of the present invention.
In the figure: 1. the system comprises a flue gas recirculation fan 2, a recirculation fan inlet adjusting baffle 3, a recirculation fan outlet adjusting baffle 4, a recirculation fan inlet pressure measuring device (remote transmission) 5, a recirculation fan outlet pressure measuring device (remote transmission) 6, a recirculation fan outlet thermocouple 7, a recirculation fan outlet flow device 8, a chimney 9, an induced draft fan 10, a primary fan 11, an air preheater 12 and a dust remover.
The specific implementation mode is as follows:
example 1:
a flue gas recirculation system for a biomass CFB boiler comprising: the device comprises a flue gas recirculation fan 1, a recirculation fan outlet flow device 7, a recirculation fan inlet pressure measuring device 4 and a recirculation fan outlet pressure measuring device 5, wherein the flue gas recirculation fan is respectively connected with a recirculation fan inlet adjusting baffle 2 and a recirculation fan outlet adjusting baffle 3, the recirculation fan inlet adjusting baffle is connected with the recirculation fan inlet pressure measuring device, the recirculation fan outlet adjusting baffle is connected with a recirculation fan outlet couple 6, the recirculation fan outlet couple is connected with the recirculation fan outlet flow device, and the recirculation fan outlet flow device is connected with the recirculation fan outlet pressure measuring device; the flue gas recirculation bypass system is formed by a series structure of the flue gas recirculation fan, the inlet adjusting baffle of the recirculation fan, the outlet adjusting baffle of the recirculation fan, the inlet pressure measuring device of the recirculation fan, the outlet thermocouple of the recirculation fan and the outlet flow device of the recirculation fan.
Example 2:
according to the flue gas recirculation system for the biomass CFB boiler in the embodiment 1, the flue gas recirculation bypass system is respectively connected with a chimney 8, an induced draft fan 9 and a primary air fan 10; the induced draft fan is connected with a dust remover 12, and the dust remover is connected with an air preheater 11; the primary air fan is connected with the air preheater.
Claims (2)
1. A flue gas recirculation system for a biomass CFB boiler comprising: flue gas recirculation fan, recirculation fan export flow device, recirculation fan import pressure measurement device and recirculation fan export pressure measurement device, characterized by: the flue gas recirculation fan is respectively connected with a recirculation fan inlet adjusting baffle and a recirculation fan outlet adjusting baffle, the recirculation fan inlet adjusting baffle is connected with a recirculation fan inlet pressure measuring device, the recirculation fan outlet adjusting baffle is connected with a recirculation fan outlet galvanic couple, the recirculation fan outlet galvanic couple is connected with a recirculation fan outlet flow device, and the recirculation fan outlet flow device is connected with a recirculation fan outlet pressure measuring device;
the flue gas recirculation bypass system is formed by a series structure of the flue gas recirculation fan, the inlet adjusting baffle of the recirculation fan, the outlet adjusting baffle of the recirculation fan, the inlet pressure measuring device of the recirculation fan, the outlet thermocouple of the recirculation fan and the outlet flow device of the recirculation fan.
2. The flue gas recirculation system for a biomass CFB boiler of claim 1, characterized by: the flue gas recirculation bypass system is respectively connected with a chimney, an induced draft fan and a primary air fan;
the induced draft fan is connected with a dust remover, and the dust remover is connected with an air preheater;
the primary air fan is connected with the air preheater.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202220577216.4U CN217082539U (en) | 2022-03-17 | 2022-03-17 | Flue gas recirculation system for biomass CFB boiler |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202220577216.4U CN217082539U (en) | 2022-03-17 | 2022-03-17 | Flue gas recirculation system for biomass CFB boiler |
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| Publication Number | Publication Date |
|---|---|
| CN217082539U true CN217082539U (en) | 2022-07-29 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202220577216.4U Active CN217082539U (en) | 2022-03-17 | 2022-03-17 | Flue gas recirculation system for biomass CFB boiler |
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| CN (1) | CN217082539U (en) |
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2022
- 2022-03-17 CN CN202220577216.4U patent/CN217082539U/en active Active
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