CFBB based on fluidised form reconstruct control nitrogen oxide
Technical field
The utility model relates to CFBB equipment, specifically a kind of control nitrogen oxide (NO based on fluidised form reconstruct
X) CFBB.
Background technology
Along with country's " thermal power plant's atmosphere pollutants emission standards " (GB13223-2011) issues and implements, require flue dust, sulfur dioxide, nitrogen oxide, mercury and the compound discharging thereof of coal-burning boiler all will reach limit value.At present, the discharging of the flue dust of CFBB, sulfur dioxide, mercury and compound thereof is set up measures such as desulfurizer by the dedusting of afterbody electricity cloth, in-furnace calcium spraying and afterbody, all can reach limit value.And for nitrogen oxide (NO
X) minimum discharge, itself and boiler combustion are closely related, at present at control nitrogen oxide (NO
X) discharge index aspect, the still right whole boiler combustion structural design of needleless.
Summary of the invention
The purpose of this utility model is to overcome the shortcoming of prior art, and a kind of CFBB based on fluidised form reconstruct control nitrogen oxide is provided, and solving does not still have minimum discharge nitrogen oxide (NO at present
X) the technical problem of CFBB.
The utility model is achieved through the following technical solutions:
A kind of CFBB of the control discharged nitrous oxides based on fluidised form reconstruct, the stationary state theory is pointed out, the bottom of CFB is the bubbling bed, top is fast bed, different coal correspondences different best bubbling beds and best fast bed state, and its essence is exactly to determine optimum fast bed and bubbling bed state.Wherein, the effect that penetrates that should spread immixture and secondary wind from heat transfer, particle agglomeration probability, the gas of material of determining of best amounts of fine particles is taken all factors into consideration, and best fine grain bed storage is to be optimized definite according to " recirculating fluidized bed fluidised form design collection of illustrative plates ".
And best coarse granule amount determine should be from bed temperature, fuel the oarse-grained abrasion condition that burns degree, heating surface, and the diffusivity that penetrates of the energy consumption of blower fan and secondary wind is considered, simultaneously, best coarse granule bed storage is to be optimized definite according to " many granularities material balance model " and " different grain size fuel burns time graph ".After the fluidised form reconstruct, the coarse granule amount that constitutes the bubbling bed significantly reduces, and the amounts of fine particles that constitutes fast bed slightly increases, total bed storage significantly reduces and fine particle fraction promotes significantly, changes based on fluidised form reconstruct minimum discharge boiler hearth of circulating fluidized bed material and can satisfy best material balance requirement.It is to keep the normal fluidisation of CFBB bed material and the fuel that enters burner hearth in time to ignite that the supporting primary air fan of boiler mainly acts on, it is in time to mend the required oxygen of fuel combustion in suitable period and zone that the supporting overfire air fan of boiler mainly acts on, both guaranteed the complete after-flame of fuel, and controlled again and produce CO, SO in the flue gas as far as possible less
XAnd NO
XBased on fluidised form reconstruct minimum discharge CFBB, because of significantly reducing, the coarse granule amount that constitutes the bubbling bed make the supporting primary air fan power of boiler to reduce greatly, reasonably the diffusivity design that penetrates of secondary wind makes the supporting overfire air fan power of boiler suitably to reduce, and whole boiler complete auxiliaries power consumption is had very big help.
A kind of CFBB based on fluidised form reconstruct control nitrogen oxide, comprise: boiler hearth of circulating fluidized bed, the separator that is communicated with the burner hearth exhanst gas outlet, the material returning device that is communicated with separator dipleg and burner hearth, introduce from air channel burner hearth air compartment, be arranged in blast cap on the air compartment air distribution plate, be distributed in the secondary air channel on the burner hearth front-back wall, separator inlet zone joins with the SNCR flue gas denitrification system, it is characterized in that: described separator is a kind ofly to be arranged in parallel at that burner hearth exhanst gas outlet zone, inlet flue duct have a down dip, the adiabatic cyclone separator of central tube off-centre; The returning charge elegance high pressure cold wind of described material returning device is sent into by little blast cap, installs flowmeter, pressure gauge and volume damper door on the inlet airduct; Described air compartment and burner hearth are separated by by air distribution plate, and the blast cap that is evenly arranged on the air distribution plate is a kind of bell-jar blast cap.
Further, described adiabatic cyclone separator is made up of the refractory material back boxing of shell and three-decker, and three layers of refractory material are respectively high-strength abrasion-proof and water material feeding, lightening casting material, light-weight insulating brick; Described adiabatic cyclone separator is provided with the operating temperature control system.
Further, described material returning device is made up of the refractory material back boxing of shell and three-decker, and three layers of refractory material are respectively high-strength abrasion-proof and water material feeding, lightening casting material, light-weight insulating brick; Described material returning device is provided with the operating temperature control system.
Further, described air distribution plate is provided with phosphate refractory concrete.
Further, the nozzle of described secondary air channel is arranged on the lower furnace portion material needs combustion-supporting height.
The utility model compared with prior art has the following advantages and beneficial effect:
CFBB realizes that required two the core conditions that possess of fluidised form reconstruct are: the one-tenth ash abrasion characteristic that at first should understand relevant bunker coal in advance, promptly by coal being carried out hot static combustion and cold state vibration screen mill consumption mode is analyzed, solve current in the world must be in hot drawback of testing down.Next is to guarantee that the circulatory system has separative efficiency efficiently, guarantee circulating particle concentration (heat porter) and particle diameter distribution in the boiler circulatory system, make material sample analysis under the separator: d50 is at 10~12um, d99 is in 100um, and whole circulation loop solid circulating rate satisfies running status 2.5~3.0Kg/Nm
3Requirement.
The utility model is owing to be arranged in juxtaposition the thermal insulation cyclone separator at furnace outlet, the burner hearth gas fume after burning enters cyclone separator through furnace outlet, the feed separation that flue gas is carried secretly is got off, return burner hearth circulation combustion again by material returning device, separative efficiency is very high; One time wind evenly enters burner hearth through air compartment by blast cap, fluidized bed material, secondary wind are sent into the space that the burning of lower furnace portion material needs air by being distributed in the secondary air channel nozzle on the burner hearth front-back wall, guarantee that burning changes the oxygen-excess combustion stage over to from reducing atmosphere, has improved efficiency of combustion.Optimizing and revising of stove internal combustion air distribution makes the initial nitrogen oxide (NO of boiler
X) generate and to be controlled at than low value.
The utility model is applicable to the CFBB of fluidised form reconstruct, makes boiler furnace outlet nitrogen oxide (NO by burning control
X) to produce total amount on the low side.
Description of drawings
Fig. 1 is a structural representation of the present utility model.
The utility model is further described by preferred embodiment below in conjunction with accompanying drawing.
The specific embodiment
As shown in Figure 1, a kind of CFBB based on fluidised form reconstruct control nitrogen oxide, comprise: boiler hearth of circulating fluidized bed 1, the separator 2 that is communicated with the burner hearth exhanst gas outlet, the material returning device 3 that is communicated with separator dipleg and burner hearth 1, introduce from air channel burner hearth air compartment 5, be arranged in blast cap 4 on the air compartment air distribution plate, be distributed in the secondary air channel 6 on the burner hearth front-back wall, separator 2 entrance areas and SNCR flue gas denitrification system join.
Described SNCR flue gas denitrification system is by ammoniacal liquor unloading and storage system 7, ammoniacal liquor and dilution water induction system 8, mixing and dispensing system 9 and spraying system 10 are formed, described ammoniacal liquor unloading and stocking system 7 are by ammoniacal liquor tank car 71, ammoniacal liquor discharging pump installation 72 and tank used for storing ammonia 73 constitute, described ammoniacal liquor and dilution water induction system 8 are by demineralized water 81, ammoniacal liquor dosing pump assembly 82 and dilution water dosing pump assembly 83 constitute, described mixing and dispensing system 9 is made of static mixer 91 and reducing agent distributor 92, described spraying system 10 is by being arranged on the separator inlet zone, be distributed to whole flue cross section, the injector head 101 that connects compressed air source constitutes, described tank used for storing ammonia 73 connects described ammoniacal liquor dosing pump assembly 82, described dilution water dosing pump assembly 83, ammoniacal liquor dosing pump assembly 82 is connected with described static mixer 91, described static mixer 91 connects described reducing agent distributor 92, and described reducing agent distributor 92 is connected with described injector head 101.
Described separator 2 is a kind ofly to be arranged in parallel at that burner hearth exhanst gas outlet zone, inlet flue duct have a down dip, the adiabatic cyclone separator of central tube off-centre.
Described adiabatic cyclone separator is made up of the refractory material back boxing of shell and three-decker, and three layers of refractory material are respectively high-strength abrasion-proof and water material feeding, lightening casting material, light-weight insulating brick; Described adiabatic cyclone separator is provided with the operating temperature control system.
Described material returning device 3 is made up of the refractory material back boxing of shell and three-decker, and three layers of refractory material are respectively high-strength abrasion-proof and water material feeding, lightening casting material, light-weight insulating brick; The returning charge elegance high pressure cold wind of described material returning device is sent into by little blast cap, and the female pipe of inlet airduct is gone up installing flowmeter, pressure gauge and volume damper door; Described material returning device 3 is provided with the operating temperature control system.
Described air compartment 5 is separated by by air distribution plate with burner hearth, and the blast cap 4 that is evenly arranged on the air distribution plate is a kind of bell-jar blast caps, and described air distribution plate is provided with phosphate refractory concrete.
The nozzle of described secondary air channel 6 is arranged on the lower furnace portion material needs combustion-supporting height.
Core components such as separator 2, material returning device 3, blast cap 4, air compartment 5, secondary air channel 6, design with becoming ash abrasion characteristic according to the fuel element analysis:
Separator 2 is important composition parts of CFBB, and the utility model is arranged in juxtaposition the thermal insulation cyclone separator at furnace outlet, adopts inlet flue duct to have a down dip, the mode of central tube off-centre, and both simple in structure, separative efficiency is high again.
Enter cyclone separator in the burner hearth gas fume after burning through furnace outlet, the feed separation that flue gas is carried secretly is got off, return burner hearth circulation combustion again by material returning device.Flue gas after the separation flows to the afterbody convection heating surface through central tube.The operating temperature of controlling whole feed separation and returning charge loop is for helping ultralow discharged nitrous oxides optimum temperature.
The part weight of the straight section of cyclone separator, awl section, dipleg and material returning device is supported on the steelframe; The flue of separator outlet is suspended on the furnace roof top board by suspension rod.
A material returning device 3 all is equipped with in the bottom of each separator dipleg, is provided with air distribution plate in the material returning device, ash-removing mouth on the air distribution plate.
The wind in combustion chamber is introduced air compartment from the air channel.Air compartment 5 is separated by by air distribution plate with burner hearth, and air distribution plate is a membrane wall structure, evenly arranges the bell-jar blast cap on it, accurate casting, and special material, the serviceability temperature height has long service life.Be the protecting cloth aerofoil, the phosphate refractory concrete thickness on the air distribution plate is suitable.
Secondary wind is sent into the height space that the burning of lower furnace portion material needs air by being distributed in the secondary air channel nozzle on the burner hearth front-back wall.Guarantee that burning changes the oxygen-excess combustion stage over to from reducing atmosphere, improve efficiency of combustion, reduce the afterbody unburned carbon in flue dust, the secondary blast just in time can penetrate the anoxic zone during operation.
Based on fluidised form reconstruct minimum discharge CFBB general structure design, guarantee the one-tenth ash abrasion characteristic of the boiler furnace flue gas rate of climb according to bunker coal, keep the best flue gas rate of climb of burner hearth in 4.5~5m/s scope, suitable recycle stock amount guarantees that boiler operatiopn bed temperature, furnace outlet gas temperature, separator material air-teturning temperature and separator outlet temperature are all between 850~880 ℃ of optimum responses, range of temperature is at 50 ℃, the NO of the actual generation of boiler combustion
XIt is international that product is on the low side greatly usually.Adding burns before boiler furnace front-back wall overfiren air port sprays into is in reducing atmosphere, NO
XOriginal concentration can be controlled in and is lower than 150mg/Nm
3According to present actual design result, on based on fluidised form reconstruct minimum discharge CFBB, do not increase the expensive out of stock device of afterbody SCR, the SNCR denitrification apparatus that cooperates lower cost just can reach boiler tail flue gas NO among the national GB13223-2011 " thermal power plant's atmosphere pollutants emission standards "
XDischarging is less than 100mg/Nm
3Requirement.