CN112413569A - High-speed jet flow over-fire air device with circulating flue gas - Google Patents

High-speed jet flow over-fire air device with circulating flue gas Download PDF

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Publication number
CN112413569A
CN112413569A CN202011095648.3A CN202011095648A CN112413569A CN 112413569 A CN112413569 A CN 112413569A CN 202011095648 A CN202011095648 A CN 202011095648A CN 112413569 A CN112413569 A CN 112413569A
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China
Prior art keywords
air
flue gas
circulating flue
channel
layer
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CN202011095648.3A
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Chinese (zh)
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CN112413569B (en
Inventor
张忠孝
陈宝明
白昊
郭欣维
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Shanghai Jiaotong University
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Shanghai Jiaotong University
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23B—METHODS OR APPARATUS FOR COMBUSTION USING ONLY SOLID FUEL
    • F23B80/00—Combustion apparatus characterised by means creating a distinct flow path for flue gases or for non-combusted gases given off by the fuel
    • F23B80/02—Combustion apparatus characterised by means creating a distinct flow path for flue gases or for non-combusted gases given off by the fuel by means for returning flue gases to the combustion chamber or to the combustion zone
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23C—METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN  A CARRIER GAS OR AIR 
    • F23C9/00—Combustion apparatus characterised by arrangements for returning combustion products or flue gases to the combustion chamber
    • F23C9/06—Combustion apparatus characterised by arrangements for returning combustion products or flue gases to the combustion chamber for completing combustion
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23C—METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN  A CARRIER GAS OR AIR 
    • F23C9/00—Combustion apparatus characterised by arrangements for returning combustion products or flue gases to the combustion chamber
    • F23C9/08—Combustion apparatus characterised by arrangements for returning combustion products or flue gases to the combustion chamber for reducing temperature in combustion chamber, e.g. for protecting walls of combustion chamber
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23L—SUPPLYING AIR OR NON-COMBUSTIBLE LIQUIDS OR GASES TO COMBUSTION APPARATUS IN GENERAL ; VALVES OR DAMPERS SPECIALLY ADAPTED FOR CONTROLLING AIR SUPPLY OR DRAUGHT IN COMBUSTION APPARATUS; INDUCING DRAUGHT IN COMBUSTION APPARATUS; TOPS FOR CHIMNEYS OR VENTILATING SHAFTS; TERMINALS FOR FLUES
    • F23L9/00—Passages or apertures for delivering secondary air for completing combustion of fuel 
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23C—METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN  A CARRIER GAS OR AIR 
    • F23C2202/00—Fluegas recirculation
    • F23C2202/30—Premixing fluegas with combustion air
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E20/00—Combustion technologies with mitigation potential
    • Y02E20/34—Indirect CO2mitigation, i.e. by acting on non CO2directly related matters of the process, e.g. pre-heating or heat recovery

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)

Abstract

A high-speed jet over-fire air device with circulating flue gas, comprising: compound spout of over fire air, wind channel, swing connecting piece, connecting rod, connecting axle and swing handle, wherein: the overfire air composite nozzle is positioned at the outlet end of the air duct, the swing connecting piece is fixedly arranged on the overfire air composite nozzle and is connected with a connecting rod positioned in the air duct, the connecting rod is connected with a connecting shaft movably arranged in the air duct, and the swing angle of the nozzle is adjusted through a swing handle arranged on the outer side of the air duct. According to the invention, through the reasonably designed composite nozzle, under the condition of high air-burn-out rate, low-temperature flue gas at the tail part of the boiler replaces partial air as air-burn-out air to be fully mixed with ascending air flow in the boiler in a high-speed jet flow mode, so that carbon particles and CO combustible substances which are not fully combusted in a main combustion area are fully combusted, NOx emission is reduced through the high air-burn-out rate, meanwhile, full combustion of fuel is ensured, and the boiler efficiency is improved.

Description

High-speed jet flow over-fire air device with circulating flue gas
Technical Field
The invention relates to the technology in the field of coal stove equipment of a thermal power plant, in particular to a high-speed jet flow over-fire air device with circulating flue gas.
Background
The coal-fired thermal power plant is a main emission source of NOx in atmospheric pollutants, the air staged combustion technology is a technical means for reducing NOx commonly used by the conventional coal-fired unit, has the characteristics of low investment, simple operation, less later maintenance and the like, and becomes a technology which is preferably considered in the conventional boiler transformation. The over-fire air ratio proportion and the device in the air staged combustion technology play a key role in the low-nitrogen combustion effect. The over-fire air rate in the traditional air classification technology is generally 10% -20%, the highest denitration efficiency is about 50%, and the requirement of the current thermal power plant for realizing ultralow NOx emission cannot be met. Research shows that the denitration efficiency can reach about 70% when the over-fire air rate is 30% -40%, but the problems of insufficient fuel combustion, high outlet temperature and the like of a main combustion area exist, so that CO emission at the outlet of a hearth, the carbon content of fly ash and the exhaust temperature are increased, the boiler efficiency is reduced, and the method does not conform to the concept of high-efficiency and clean utilization of energy advocated at present. The key to breaking through the bottleneck of air classification technology development is how to solve the contradiction of improving the over-fire air rate and reducing the incomplete combustion loss.
Disclosure of Invention
Aiming at the problems, the invention provides a high-speed jet flow over-fire air device with circulating flue gas, and by means of a reasonably designed composite nozzle, under the condition of improving over-fire air rate, low-temperature flue gas at the tail part of a boiler replaces partial air as over-fire air to be fully mixed with ascending air flow in the boiler in a high-speed jet flow mode, so that carbon particles and combustible substances such as CO which are not fully combusted in a main combustion zone are fully combusted, NOx emission is reduced through high over-fire air rate, meanwhile, full combustion of fuel is guaranteed, and boiler efficiency is improved.
The invention is realized by the following technical scheme:
the invention comprises the following steps: compound spout of over fire air, wind channel, swing connecting piece, connecting rod, connecting axle and swing handle, wherein: the overfire air composite nozzle is positioned at the outlet end of the air duct, the swing connecting piece is fixedly arranged on the overfire air composite nozzle and is connected with a connecting rod positioned in the air duct, the connecting rod is connected with a connecting shaft movably arranged in the air duct, and the swing angle of the nozzle is adjusted through a swing handle arranged on the outer side of the air duct.
The compound spout of overfire air adopt the integrative casting of heat-resisting cast iron of high temperature to become, be equipped with baffle and support piece in the spout, wherein: the partition plate divides the whole nozzle into an upper-layer air channel, an upper-layer circulating flue gas channel, a middle-layer air channel, a lower-layer circulating flue gas channel and a lower-layer air channel, wherein the upper-layer circulating flue gas channel and the lower-layer circulating flue gas channel are respectively fixed in the upper-layer air channel and the lower-layer air channel through support pieces.
Upper and lower floor's circulation flue gas passageway be connected with the circulation flue gas pipeline that corresponds through upper and lower layer circulation flue gas pipeline connecting piece respectively, wherein: the circulating flue gas pipeline connecting piece is of a heat-resistant metal hose structure, so that the nozzle can flexibly adjust the angle conveniently.
The spout swings, the horizontal swing range is 20 degrees, and the up-and-down swing range is 30 degrees.
The upper and lower layers of circulating flue gas channels are circular, and the upper and lower layers of air channels are rectangular.
Technical effects
The invention integrally solves the problems of insufficient fuel combustion and high outlet smoke temperature under the existing high over-fire air rate, and the over-fire air composite nozzle is provided with an upper layer of circulating smoke channel and a lower layer of circulating smoke channel, the circulating smoke is pressurized by a high-pressure circulating fan to form high-speed smoke jet, and can entrain the surrounding air to form high-speed over-fire air with strong rigidity, and the high-speed over-fire air is sprayed to the center of a hearth and is fully mixed with rising smoke in a furnace, so that the completely combusted carbon in the smoke is fully combusted; meanwhile, the low-temperature circulating flue gas replaces part of air (generally hot air with the temperature of 250-300 ℃), so that the temperature of the flue gas at the outlet of the hearth can be effectively reduced, the boiler efficiency can reach the standard under the condition of high air burn-out rate, and the aims of high efficiency and low emission in coal combustion are fulfilled.
Compared with the prior art, the invention mixes the low-temperature flue gas with the hot air required by combustion through the high-pressure circulating fan under the condition of high burnout air rate, forms high-speed jet flow through the nozzles which are reasonably arranged, and fully mixes the oxygen required by combustion with the flue gas at the center of the hearth through the winding and absorbing action, thereby solving the problem of burnout of incompletely combusted carbon in the flue gas, avoiding the defect of the burnout air caused by the hot air with small jet flow rigidity in the traditional technology, reducing the flue gas temperature at the outlet of the hearth through the low-temperature circulating flue gas, reducing the smoke exhaust loss and improving the boiler efficiency.
Drawings
FIG. 1 is a schematic structural view of the present invention;
FIG. 2 is a schematic view of FIG. 1A-A;
FIG. 3 is a schematic structural view of an over-fire air nozzle;
in the figure: the device comprises an over-fire air composite nozzle 1, an air channel 2, a swing connecting piece 3, an upper layer circulating flue gas pipeline connecting piece 4, a lower layer circulating flue gas pipeline connecting piece 5, an upper layer circulating flue gas pipeline 6, a lower layer circulating flue gas pipeline 7, a connecting rod 8, a connecting shaft 9, a swing handle 10, an upper layer air channel 11, an upper layer circulating flue gas channel 12, a partition plate 13, a middle layer air channel 14, a lower layer circulating flue gas channel 15, a lower layer air channel 16 and a supporting piece 17.
Detailed Description
As shown in fig. 1, the high-speed jet flow over-fire air device with circulating flue gas according to the present embodiment includes: the device comprises an over-fire air composite nozzle 1, an air duct 2, a swing connecting piece 3, an upper layer circulating flue gas pipeline connecting piece 4, a lower layer circulating flue gas pipeline connecting piece 5, an upper layer circulating flue gas pipeline 6, a lower layer circulating flue gas pipeline 7, a connecting rod 8, a connecting shaft 9 and a swing handle 10.
The over-fire air composite nozzle 1 comprises: upper air passageway 11, upper circulation flue gas passageway 12, baffle 13, middle level air passageway 14, lower floor's circulation flue gas passageway 15, lower floor's air passageway 16, support piece 17, wherein: the 6 circulating flue gas channels are arranged in the upper layer air channel 11 and the lower layer air channel 16, and the air quantity of each channel can be automatically adjusted, so that the jet momentum of each channel is maximized.
Circulation flue gas passageway 12 and 15 be circular spout, spout diameter D and the 6 width L of the overfire air spout are than being 1: (4.3-5.8), the entrainment of the high-speed flue gas jet flow to the air can be increased to the greatest extent in the range, so that the mixed airflow formed by the high-speed flue gas jet flow and the air has stronger rigidity, the mixed airflow can penetrate through the flue gas to enter the center of a hearth, and each layer is respectively provided with three circulating flue gas channels. The air quantity and the circulating flue gas air quantity are mutually independently controlled, and the circulating flue gas quantity accounts for 20-40% of the total quantity of the over-fire air.
The horizontal swing range of the over-fire air nozzle 1 is 20 degrees, and the up-and-down swing range is 30 degrees.
The cold flue gas is pressurized and sent into a circulating flue gas pipeline through a high-pressure circulating fan, jet flow from a circulating flue gas channel is high-speed jet flow, and the wind speed is 120-140 m/s; the jet flow speed from the air channel is 60-80 m/s, the high-speed flue gas jet flow can entrain air to enhance the jet flow rigidity of the over-fire air, so that the mixed over-fire air enters the central area of the hearth to be fully mixed with the flue gas, and the emission of unburned products of CO and fly ash combustible materials is reduced.
The foregoing embodiments may be modified in many different ways by those skilled in the art without departing from the spirit and scope of the invention, which is defined by the appended claims and all changes that come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

Claims (5)

1. The utility model provides a high-speed efflux over fire air device with circulation flue gas which characterized in that includes: compound spout of over fire air, wind channel, swing connecting piece, connecting rod, connecting axle and swing handle, wherein: the overfire air composite nozzle is positioned at the outlet end of the air duct, the swing connecting piece is fixedly arranged on the overfire air composite nozzle and is connected with a connecting rod positioned in the air duct, the connecting rod is connected with a connecting shaft movably arranged in the air duct, and the swing angle of the nozzle is adjusted through a swing handle arranged on the outer side of the air duct.
2. The high-speed jet flow over-fire air device with the circulating flue gas as claimed in claim 1, wherein the over-fire air composite nozzle is integrally cast by high-temperature heat-resistant cast iron, and a partition plate and a support member are arranged in the nozzle, wherein: the partition plate divides the whole nozzle into an upper-layer air channel, an upper-layer circulating flue gas channel, a middle-layer air channel, a lower-layer circulating flue gas channel and a lower-layer air channel, wherein the upper-layer circulating flue gas channel and the lower-layer circulating flue gas channel are respectively fixed in the upper-layer air channel and the lower-layer air channel through support pieces.
3. The high-speed jet flow over-fire air device with the circulating flue gas as claimed in claim 1, wherein the upper and lower circulating flue gas channels are respectively connected with the corresponding circulating flue gas pipelines through upper and lower circulating flue gas pipeline connecting pieces.
4. The high velocity jet overfire air apparatus with recirculated flue gas as claimed in claim 1, wherein said nozzle is oscillating in a horizontal oscillation range of 20 ° and in an up and down oscillation range of 30 °.
5. The high velocity jet overfire air device with recirculated flue gas of claim 1, wherein said upper and lower level recirculated flue gas passages are circular and said upper and lower level air passages are rectangular.
CN202011095648.3A 2020-10-14 2020-10-14 High-speed jet flow over-fire air device with circulating flue gas Active CN112413569B (en)

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DE20002136U1 (en) * 2000-02-08 2000-06-15 Buderus Heiztechnik Gmbh Gas forced draft burner
JP2000199610A (en) * 1998-12-28 2000-07-18 Ottoo:Kk LOW NOx RADIANT TUBE BURNER
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CN101476739A (en) * 2009-01-21 2009-07-08 哈尔滨工业大学 W-shaped flame boiler with two-stage over-fire wind
CN201925914U (en) * 2010-10-29 2011-08-10 烟台龙源电力技术股份有限公司 Over-fire air spout layout structure
CN103234199A (en) * 2013-04-27 2013-08-07 上海交通大学 Swing type over-fire air device, over-fire air system and over-fire air control method
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CN108905590A (en) * 2018-08-13 2018-11-30 中国华能集团有限公司 A kind of denitrating system and method for station boiler low NO collaboration high temperature spray ammonia
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CN109654484A (en) * 2018-12-18 2019-04-19 哈尔滨工业大学 Spray reducing agent denitration in the stove burner in industrial coal powder boiler burner primary zone
CN109737388A (en) * 2018-12-26 2019-05-10 西安交通大学 A kind of low NO of pulverized coal preheating solutionxBoiler combustion system
CN109737389A (en) * 2019-02-27 2019-05-10 哈尔滨锅炉厂有限责任公司 A kind of quasi- eastern coal low-temperature burning control system
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DE20002136U1 (en) * 2000-02-08 2000-06-15 Buderus Heiztechnik Gmbh Gas forced draft burner
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CN101476739A (en) * 2009-01-21 2009-07-08 哈尔滨工业大学 W-shaped flame boiler with two-stage over-fire wind
CN201925914U (en) * 2010-10-29 2011-08-10 烟台龙源电力技术股份有限公司 Over-fire air spout layout structure
CN103234199A (en) * 2013-04-27 2013-08-07 上海交通大学 Swing type over-fire air device, over-fire air system and over-fire air control method
CN204880116U (en) * 2015-08-24 2015-12-16 江联重工股份有限公司 Low NOX gas combustion ware
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CN109539245A (en) * 2018-10-30 2019-03-29 西安交通大学 A kind of pulverized coal preheating solution decoupling combustion device
CN109654484A (en) * 2018-12-18 2019-04-19 哈尔滨工业大学 Spray reducing agent denitration in the stove burner in industrial coal powder boiler burner primary zone
CN109737388A (en) * 2018-12-26 2019-05-10 西安交通大学 A kind of low NO of pulverized coal preheating solutionxBoiler combustion system
CN109737389A (en) * 2019-02-27 2019-05-10 哈尔滨锅炉厂有限责任公司 A kind of quasi- eastern coal low-temperature burning control system
CN110873327A (en) * 2019-12-19 2020-03-10 上海交通大学 Ultra-low NOx combustion device suitable for small pulverized coal boiler

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