A kind of high-temperature flue gas that adopts is as the urea pyrolysis ammonia device of thermal source
Technical field
The utility model is about process for producing ammonia from urea field, and particularly a kind of high-temperature flue gas that adopts is as the urea pyrolysis ammonia device of thermal source.
Background technology
Along with the fast development of national economy and the raising of living standards of the people, energy consumption continues to increase.Consumption of coal in 2011 has reached 3,600,000,000 tons of standard coals, but makes the sharply increase of atmosphere pollution based on the Land use systems of burning.Acid rain, haze weather frequently occur, the pressure durations increase of atmospheric environment causes the discontented of national people.Country has put into effect between a series of air quality standard and air pollution emission governance standard for this reason.
In " the GB/T13223-2011 thermal power plant air pollution emission standard " of up-to-date announcement, to power plant's smoke evacuation flue gas with NO
2the discharged nitrous oxides calculated has had stricter standard, is respectively 100mg/Nm
3(new power plant construction rises on January 1st, 2012; Existing power plant reaches new standard on July 1st, 2014) and 200mg/Nm
3(W boiler/CFBB), key area performs 100mg/Nm
3standard." collection of drainage dues standard management way " specifies, from 1 day July in 2004, to nitrogen oxide (NOx) by total emission volumn charge, and its expenses standard and SO
2identical, i.e. 0.6 yuan/pollutional equivalent value, overproof doubling is charged.The issue of above standard is implemented, and indicating China will be more and more stricter to the control of the Air Pollutant Emission of thermal power plant, also promote carrying out of fire coal boiler fume pollution control work simultaneously.
Control NOx emission technology at present both at home and abroad and can be divided into denitration and denitrating flue gas two parts in combustion process.Denitration technology in combustion process mainly comprises low NO
xburner Technology, burnout degree technology, fuel-staged combustion technology and flue gas recirculating technique etc.Then be most widely used with SNCR technology SNCR and SCR technology SCR in gas denitrifying technology.Wherein SCR becomes main flow denitrification apparatus with its higher denitration efficiency (70%-90%), occupies most denitrating flue gas market.
Selective catalytic reduction (Selective Catalytic Reduction, SCR) adopts ammonia as reducing agent, under the effect of catalyst, Chemoselective reduction occurs, NO is reduced into N
2realize the effect of degraded NOx.Ammonia in the market be mainly derived from liquefied ammonia, urea and ammoniacal liquor.In order to save the more employing liquefied ammonia of energy consumption as SCR reducing agent in the application process of reality, but belong to high-risk product due to liquefied ammonia, leakage can cause the danger such as poisoning, blast, and accumulating simultaneously and transport very inconvenience, causes potential safety hazard to power plant and surrounding enviroment.Urea is reliably widely applied with its security.Urea ammonia can adopt pyrolysis or hydrolysis Ammonia Process.When current power plant adopts urea to be reducing agent, mainly carry out ammonia processed in urea pyrolysis mode.Adopt pyrolysis oven to carry out electrical heating to First air, recycling hot blast decomposes urea.The major defect of this ammonia mode processed is that energy resource consumption is excessive.
Utility model content
Main purpose of the present utility model is to overcome deficiency of the prior art, provides that a kind of simple possible, structure are simple, cost of investment is low, operating cost is low, is applicable to the urea pyrolysis ammonia-preparing device that coal-fired boiler in power plant SCR transforms.For solving the problems of the technologies described above, solution of the present utility model is:
There is provided a kind of high-temperature flue gas that adopts as the urea pyrolysis ammonia device of thermal source, comprise pyrolysis oven, also comprise bypass flue, gas baffle, mechanical atomization spray gun, flue gas flow sensor, flue-gas temperature sensor, booster fan, ash-unloading hopper, pressure sensor and temperature sensor, described pyrolysis oven adopts eddy flow pyrolysis oven;
The side of eddy flow pyrolysis oven is communicated with one end of bypass flue, the other end place of bypass flue is provided with two-way entrance, be respectively high-temperature flue gas entry and urea inlet, bypass flue is also equiped with flue gas flow sensor and flue-gas temperature sensor, for monitoring flow in bypass flue and temperature respectively; High-temperature flue gas entry place is provided with gas baffle, and for being regulated the intake of high-temperature flue gas by gas baffle, urea inlet adopts mechanical atomization spray gun, for spraying in bypass flue by mechanical atomization spray gun by urea;
The upper end of eddy flow pyrolysis oven is connected with exhaust pass, for the outlet as obtained ammonia; The tail end of exhaust pass is equipped with booster fan, pressure sensor, temperature sensor successively, the kinetic energy that booster fan sprays from exhaust pass for providing ammonia, pressure sensor and temperature sensor are respectively used to the pressure and temperature of monitoring ammonia;
Ash-unloading hopper is equipped with in the lower end of eddy flow pyrolysis oven, for discharging dust.
As further improvement, described employing high-temperature flue gas is also provided with urea metering device as the urea pyrolysis ammonia device of thermal source, mechanical atomization spray gun is connected with urea metering device, for being controlled the urea injecting quantity of gadgetize atomizing lance by urea metering device.
As further improvement, the mist entrance that described eddy flow pyrolysis oven is communicated with bypass flue, can realize mist and carry out tangential admission.
As further improvement, described high-temperature flue gas entry is arranged near the high temperature superheater of boiler, and the high-temperature flue gas introducing bypass flue refers to the flue gas of temperature between 600 ~ 800 DEG C.
As further improvement, the exhaust pass end of described eddy flow pyrolysis oven is connected to and sprays grid (SCR sprays grid), spraying grid is arranged in the pipeline that is connected with high temperature superheater, from the ammonia of exhaust pass tail end ejection, realize entrainmenting with boiler original flue gas mixing by booster fan.
Compared with prior art, the beneficial effects of the utility model are:
1, a small amount of high-temperature flue gas near the utility model employing high temperature superheater, as the thermal source of urea pyrolysis, adopts cheap low-grade energy to substitute high-grade energy, reduces the power consumption needed for urea pyrolysis and operating cost;
2, the utility model employing eddy flow pyrolysis oven effectively reduces the dust content in flue gas, decrease the wearing and tearing of dust to booster fan, improve the working environment of booster fan, extend booster fan service life, ensure the Homogeneous phase mixing of urea and high-temperature flue gas simultaneously, improve the pyrolysis efficiency of urea;
3, the utility model device integration is high, and operation runs easy;
4, the utility model small investment, operation and maintenance cost is low;
5, the high-temperature flue gas carrying urea liquid in the utility model eddy flow pyrolysis oven is strong rotational flow, enhance mixing and heat exchange of solution and flue gas, effectively prevent the insufficient pyrolysis oven intercrystalline caused of urea pyrolysis, simultaneously strong disturbance ensures that in pyrolysis oven exit gas, ammonia concentration is even.
Accompanying drawing explanation
Fig. 1 is overall structure schematic diagram of the present utility model.
Reference numeral in figure is: 1 gas baffle; 2 urea metering devices; 3 mechanical atomization spray guns; 4 bypass flues; 5 flue gas flow sensors; 6 flue-gas temperature sensors; 7 eddy flow pyrolysis ovens; 8 ash-unloading hoppers; 9 booster fans; 10 pressure sensors; 11 temperature sensors; Flue near 12 high temperature superheaters; 13 spray grid.
Detailed description of the invention
Below in conjunction with accompanying drawing and detailed description of the invention, the utility model is described in further detail:
A kind of high-temperature flue gas that adopts as shown in Figure 1 as the urea pyrolysis ammonia device of thermal source, adopt eddy flow pyrolysis oven 7 as the reactor of urea pyrolysis and with diluent media (flue gas) well-mixed blender.This kind adopts high-temperature flue gas to comprise eddy flow pyrolysis oven 7, bypass flue 4, gas baffle 1, urea metering device 2, mechanical atomization spray gun 3, flue gas flow sensor 5, flue-gas temperature sensor 6, booster fan 9, ash-unloading hopper 8, pressure sensor 10 and temperature sensor 11 as the urea pyrolysis ammonia device of thermal source.
The side of eddy flow pyrolysis oven 7 is communicated with one end of bypass flue 4, and the other end place of bypass flue 4 is provided with two-way entrance, is respectively the high-temperature flue gas entry as thermal source and the urea inlet as low-temperature receiver.High-temperature flue gas entry place is provided with gas baffle 1, for being regulated the intake of high-temperature flue gas by gas baffle 1; Near High-temperature Superheater In A Boiler, a small amount of high-temperature flue gas is introduced bypass flue 4 by the correct position of flue 12, and the temperature of high-temperature flue gas is between 600 ~ 800 DEG C.Urea inlet adopts mechanical atomization spray gun 3, for spraying in bypass flue 4 by mechanical atomization spray gun 3 by urea; Mechanical atomization spray gun 3 is connected with urea metering device 2, for being controlled the reducing agent urea injecting quantity of gadgetize atomizing lance 3 by urea metering device 2.Bypass flue 4 being also equiped with flue gas flow sensor 5 and flue-gas temperature sensor 6, for monitoring flow in bypass flue 4 and temperature respectively, making flue-gas temperature control at 550 ~ 650 DEG C, meet the ammonia concentration of 5% simultaneously.Urea after atomization is loaded into Homogeneous phase mixing in eddy flow pyrolysis oven 7 by high-temperature flue gas and pyrolysis becomes ammonia.Namely this device ensure that the uniformity coefficient of gas-liquid mixed and the time of staying of pyrolytic reaction, again saves the energy consumption that existing pyrolysis oven needs Electric heating to bring, and reduces the content of dust in flue gas simultaneously.
The exhaust pass of the upper end of eddy flow pyrolysis oven 7, for the outlet as pyrogenically prepared ammonia.The end of outlet pyrolysis ammonia flue is equipped with booster fan 9, pressure sensor 10 and temperature sensor 11 successively, is connected to SCR and sprays grid 13 entrance, and the ammonia realizing spraying grid 13 ejection mixes with entrainmenting of boiler smoke.In order to ensure the normal required pressure of ammonia-spraying grid, the resistance of booster fan 9 for providing ammonia to overcome the nozzle spraying grid 13 is set, and the entrainment kinetic energy mix required for of injection ammonia with former flue gas is provided.Pressure sensor 10 and temperature sensor 11, be respectively used to monitor ammonia at the pressure and temperature spraying grid 13 entrance.
Ash-unloading hopper 8 is equipped with in the lower end of eddy flow pyrolysis oven 7, for discharging the dust after being separated with the ammonia of 5% in flue gas.Dust a large amount of in boiler smoke can cause booster fan 9 blade wear, can reduce booster fan 9 and wear and tear, increase the service life after this device dedusting.
This kind adopts high-temperature flue gas as the urea pyrolysis ammonia device of thermal source, solves high temperature heat source problem needed for urea pyrolysis, urea and mixes problem and the high high-temperature flue gas of dustiness with flue gas to the wear problem of booster fan 9; And this equipment to have integrated level high, operation runs easy, the feature that pyrolysis is effective, is particularly suitable for the preparation of coal-burning boiler SCR reducing agent.
Finally, it should be noted that above what enumerate is only specific embodiment of the utility model.Obviously, the utility model is not limited to above embodiment, can also have a lot of distortion.All distortion that those of ordinary skill in the art can directly derive or associate from content disclosed in the utility model, all should think protection domain of the present utility model.