Reduce method and the water-coal-slurry spray gun of cement rotary kiln NOx
Technical field
The present invention relates to a kind of apparatus and method that reduce the NOx of new type nonaqueous cement factory discharge capacity, specifically, be a kind of water-coal-slurry spray gun that is used to reduce cement rotary kiln NOx, and utilize it to carry out the method for denitration.
Background technology
New dry cement production technology is the dominance technology of current cement production process, but because of the operating feature of its high-temperature calcination, can in waste gas, produce oxynitrides (general designation NOx) inevitably, and it is one of main exhaust emission of cement industry.At present; The denitration technology of new type nonaqueous cement industry both at home and abroad has; On-catalytic selective reduction method (SNCR), catalysis selective reduction method (SCR), electronic beam method, reducing atmosphere method or the like; Take all factors into consideration factors such as investment cost, operation stability, maintenance cost, said method all fails on cement industry, to obtain significant results at present.Along with the continuous aggravation of global atmosphere pollution situation and China to the improving constantly of environmental requirement, need badly a kind of effectively and meet the novel denitration technology of the current cement industry current situation of China.
CN1804459A discloses a kind of re-burning denitration of coal water slurry method and device thereof, denitration efficiency is reached more than 50%, but this method is only applicable to the heat power plant boiler denitration.CN101907295A discloses a kind of low-NOx combustor for combusting coal water slurry and combustion method, and its combustion characteristics and physical dimension still can not be used in the new type nonaqueous cement industrial rotary kiln.US5746144 discloses a kind of technology of power plant boiler combined desulfurization and denitration, thereby utilizes the spray gun of special construction and nozzle above boiler economizer, to spray into the effect that mixed liquors such as water-coal-slurry, lime, urea reach desulphurization denitration.US2005/0284347A1 discloses a kind of method that reduces the NOx discharging through water spray in rotary kiln; Firing system NOx discharge capacity can be reduced about 10%~20%; Injection flow rate is: 4~5.3 U.S. gallon per minute (about 15.14~20.06 liters/minute); But it is the test of on 230t/d large-scale production line, carrying out; Not research experiment on more massive production line, and injection flow rate needs to increase along with the increase of production scale and coal consumption.
Summary of the invention
The purpose of this invention is to provide a kind of simple in structurely, easy to use, can effectively reduce the water-coal-slurry spray gun of cement rotary kiln NOx.
The water-coal-slurry spray gun of reduction cement rotary kiln NOx of the present invention, comprise the outer tube that is used for the water flowing coal slurry be used for logical compressed-air actuated in pipe, outer tube sleeve outside interior pipe, an end of pipe and outer tube in atomizer gets lodged in; Have the mixed aerosol passage in the nozzle, an end of mixed aerosol passage communicates with interior tube chamber and outer lumen respectively.
When using this water-coal-slurry spray gun, utilize compressed air that water-coal-slurry is sprayed in the cement rotary kiln through after the atomizer atomizing, water-coal-slurry is carburation by evaporation in high-temperature flue gas then, and forms certain density CO and H
2Chemical reaction will take place NOx will be changed into free of contamination N in distributed areas, these reducing atmospheres with the NOx in the firing system
2Water-coal-slurry spray into the flame temperature peak value that also can eliminate the triple channel coal burner, avoid the appearance of excessive temperature, thereby further contain the generation of NOx.Water-coal-slurry is to mix the heterogeneous liquid-solid suspension body that obtains by coal dust, water and little additive, is the liquid fuel that a kind of cleaning uses.
Above-mentioned water-coal-slurry spray gun, interior pipe and outer coaxial tube are provided with the support that circumferentially is uniformly distributed with along interior pipe between outer tube wall and outer wall of inner tube.
Above-mentioned water-coal-slurry spray gun, atomizer are Y type atomizers.
Above-mentioned water-coal-slurry spray gun, it also comprises the torch oil gun pipeline, described outer tube is supported in the torch oil gun pipeline through bracing frame.
The present invention provides a kind of simple, method of effectively reducing cement rotary kiln NOx simultaneously.
The method of this reduction cement rotary kiln NOx is the compressed air atomizing through 0.1~1MPa of 10%~50% water-coal-slurry with quality of pc concentration, and the water-coal-slurry mass flow is sprayed into the rotary kiln burning under the situation of 500~2000Kg/h.
The method of above-mentioned reduction cement rotary kiln NOx uses foregoing water-coal-slurry spray gun that water-coal-slurry is sprayed into rotary kiln, and water-coal-slurry feeds outer tube, pipe in compressed air feeds.Preferably, the outer tube of said water-coal-slurry spray gun is supported in the torch oil gun pipeline of cement rotary kiln triple channel coal burner through bracing frame.Compressed air pressure is 0.1~1MPa.Utilize screw pump that water-coal-slurry is delivered to the outer tube of spray gun, the screw pump outlet pressure is 1~6MPa.According to the designing requirement of Y type atomizer, need within this pressure limit, just can reach good atomizing effect.
The present invention provides a kind of new type nonaqueous cement industrial rotary kiln with low NOx water-coal-slurry spray gun, and utilizes it to carry out the method for denitration.Beneficial effect of the present invention:
(1) in cement rotary kiln, spraying into the suitable quantity of water coal slurry not only can not influence the thermal regulation that clinker burns till, and can also reduce the NOx discharge capacity of firing system to a certain extent;
(2) water-coal-slurry gets into after atomizing in the rotary kiln, carburation by evaporation in the high-temperature flue gas environment, and form certain density CO and H
2Distributed areas become N with the NOx reaction conversion in the firing system
2
(3) spraying into of water-coal-slurry reduced triple channel coal burner outlet flame temperature peak value, the generation of containment heating power type NOx;
(4) the water-coal-slurry spray gun structure is simple, and is easy to operate, and makes full use of idle triple channel coal burner torch oil gun pipeline, do not influence the normal operation and the operation of coal burner;
(5) cost of material of preparation water-coal-slurry is low, the few easy care of equipment investment, and system operation cost is low.
Description of drawings
Fig. 1 uses the water-coal-slurry spray gun structure outline drawing that will hang down NOx for cement rotary kiln.
Fig. 2 is the A-A cutaway view Amplified image among Fig. 1.
Fig. 3 is the method for denitration schematic flow sheet.
Fig. 4 is the atomizer enlarged drawing among Fig. 1.
Among the figure, pipe in the 1-; The 2-outer tube; The 3-pulp-inlet pipe; The outer pipe holder of 4-; The 5-atomizer; 6-torch oil gun pipeline; Pipe holder in the 7-; The 8-circulating line; Tube chamber in the 9-; 10-mixed aerosol passage; The 11--rotary kiln; 12-kiln hood cover; 13-coal powder injection pipe; The 14-burner; The 15-air compressor machine; The 16-ball valve; 17-water-coal-slurry screw pump; 18-water-coal-slurry agitator tank; 19-kiln hood platform; 20-air communication passage; 21 water-coal-slurry communication passage.
The specific embodiment
Below in conjunction with Fig. 1-3, the present invention is further set forth.
The agent structure that reduces the water-coal-slurry spray gun of cement rotary kiln NOx (low NOx) is made up of coaxial interior pipe 1 and outer tube 2, sleeve structure ringwise, and interior pipe advances pressure-air, and outer tube injects water-coal-slurry through pulp-inlet pipe 3.Between outer tube wall and outer wall of inner tube, be provided with the interior pipe holder 7 that is uniformly distributed with along interior pipe circumferential and axial.Outer tube outer wall is welded with bracing frame (outer pipe holder) 4, also is uniformly distributed with along the radial and axial of outer tube.Gun head is provided with Y type water-coal-slurry atomizing nozzle 5, has the mixed aerosol path 10 in the nozzle, the left part of mixed aerosol passage respectively through air communication passage 20 and water-coal-slurry communication passage 21 and interior tube chamber and outer lumen through communicating.Referring to Fig. 4, because of air communication passage 20, water-coal-slurry communication passage 21 and mixed aerosol path 10 " Y " type structure, so be referred to as y-type nozzle (this is the title of being used to of nozzle industry).Whole spray gun places in the torch oil gun pipeline 6 of triple channel burner 14.Referring to Fig. 2, burner 14 links to each other with coal powder injection pipe 13.Coal powder injection pipe 13 is arranged on the kiln hood cover 12 of end of rotary kiln 11.Water spray coal slurry and pressure-air be (outer lumen) 8 of the circulating line between inner and outer pipes and pipeline (interior tube chamber) 9 entering atomizers 5 respectively, finally from mixed aerosol path 10 atomizing ejection, get in the rotary kiln 11.Be placed with water-coal-slurry agitator tank 18 on the kiln hood operating platform burning till, the satisfactory water-coal-slurry that makes is delivered to the pulp-inlet pipe 3 of water-coal-slurry spray gun through screw pump 17.Pressure-air is provided by air compressor 15.
Pour coal dust, water, stabilizing agent into the water-coal-slurry agitator tank after metering, continuous stirring 30~60min under the normal temperature and pressure makes the water-coal-slurry that concentration and viscosity are fit to application, is delivered to spray gun afterbody pulp-inlet pipe through screw pump.Control screw pump outlet pressure through adjusting screw(rod) pump discharge ball valve, is controlled the water-coal-slurry mass flow in 1~6MPa scope.Pressure-air is provided by air compressor machine, is delivered to interface tube in the spray gun afterbody through pipeline, and the control compressed air pressure is in 0.1~1MPa scope, to guarantee good atomizing effect.The discharge value of firing system NOx is detected by the flue gas analyzer automatic on-line that is arranged on the outlet of kiln tail C1 level tube.Spray into water-coal-slurry continuously, observation NOx emissions data.
Embodiment 1
Making mass concentration is 10% water-coal-slurry; Controlling its feed flow is 1000Kg/h, screw pump outlet pressure 1.5MPa, high-pressure air pressure 0.50MPa; Total run time is 60min, and kiln tail preheater C1 outlet NOx discharge value is dropped to about 800ppm by the preceding 860ppm of test.
Embodiment 2
Making mass concentration is 20% water-coal-slurry; Controlling its feed flow is 1000Kg/h, screw pump outlet pressure 2MPa, high-pressure air pressure 0.60MPa; Total run time is 60min, and kiln tail preheater C1 outlet NOx discharge value is dropped to about 720ppm by the preceding 840ppm of test.
Embodiment 3
Making mass concentration is 25% water-coal-slurry; Controlling its feed flow is 1000Kg/h, screw pump outlet pressure 2.5MPa, high-pressure air pressure 0.70MPa; Total run time is 60min, and kiln tail preheater C1 outlet NOx discharge value is dropped to about 700ppm by the preceding 870ppm of test.