CN109253447B - U-shaped flame low-nitrogen pulverized coal boiler - Google Patents
U-shaped flame low-nitrogen pulverized coal boiler Download PDFInfo
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- CN109253447B CN109253447B CN201710565536.1A CN201710565536A CN109253447B CN 109253447 B CN109253447 B CN 109253447B CN 201710565536 A CN201710565536 A CN 201710565536A CN 109253447 B CN109253447 B CN 109253447B
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- China
- Prior art keywords
- hearth
- flame
- combustion
- pulverized coal
- flue
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- 239000003245 coal Substances 0.000 title claims abstract description 33
- IJGRMHOSHXDMSA-UHFFFAOYSA-N nitrogen Substances N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 title claims abstract description 15
- 229910052757 nitrogen Inorganic materials 0.000 title claims abstract description 14
- 238000002485 combustion reaction Methods 0.000 claims abstract description 37
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 11
- 238000001816 cooling Methods 0.000 claims abstract description 10
- 239000002817 coal dust Substances 0.000 claims abstract description 6
- 238000004891 communication Methods 0.000 claims abstract description 5
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 4
- 239000001301 oxygen Substances 0.000 claims abstract description 4
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 4
- 230000005855 radiation Effects 0.000 claims abstract description 4
- 238000010438 heat treatment Methods 0.000 claims description 9
- 239000012528 membrane Substances 0.000 claims description 8
- 239000000446 fuel Substances 0.000 claims description 5
- 238000006477 desulfuration reaction Methods 0.000 claims description 3
- 230000023556 desulfurization Effects 0.000 claims description 3
- 239000000428 dust Substances 0.000 claims description 3
- 238000004519 manufacturing process Methods 0.000 claims description 3
- 239000000843 powder Substances 0.000 claims 1
- 230000001629 suppression Effects 0.000 claims 1
- 239000003344 environmental pollutant Substances 0.000 description 4
- 231100000719 pollutant Toxicity 0.000 description 4
- 239000002802 bituminous coal Substances 0.000 description 2
- 230000007797 corrosion Effects 0.000 description 2
- 238000005260 corrosion Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 206010022000 influenza Diseases 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- NEEVCWPRIZJJRJ-LWRDCAMISA-N 5-(benzylideneamino)-6-[(e)-benzylideneamino]-2-sulfanylidene-1h-pyrimidin-4-one Chemical compound C=1C=CC=CC=1C=NC=1C(=O)NC(=S)NC=1\N=C\C1=CC=CC=C1 NEEVCWPRIZJJRJ-LWRDCAMISA-N 0.000 description 1
- RHZUVFJBSILHOK-UHFFFAOYSA-N anthracen-1-ylmethanolate Chemical compound C1=CC=C2C=C3C(C[O-])=CC=CC3=CC2=C1 RHZUVFJBSILHOK-UHFFFAOYSA-N 0.000 description 1
- 239000003830 anthracite Substances 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 239000002737 fuel gas Substances 0.000 description 1
- 239000000295 fuel oil Substances 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 239000003921 oil Substances 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
Classifications
-
- 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
- F23C6/00—Combustion apparatus characterised by the combination of two or more combustion chambers or combustion zones, e.g. for staged combustion
- F23C6/04—Combustion apparatus characterised by the combination of two or more combustion chambers or combustion zones, e.g. for staged combustion in series connection
-
- 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
- F23L15/00—Heating of air supplied for combustion
- F23L15/04—Arrangements of recuperators
-
- 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
Abstract
The invention relates to a U-shaped flame low-nitrogen pulverized coal boiler which is designed to be double-hearth and comprises a front hearth (2), a rear hearth (3) and over-fire air (4), wherein the front hearth (2) is a main combustion zone, and the rear hearth (3) is an auxiliary combustion zone and an over-fire zone; the front hearth (2) is lower than the rear hearth (3) and is separated by a water cooling screen, and the lower parts of the front hearth are communicated to form a U-shaped communicated flue; the top of the front hearth (2) is provided with a certain inclination angle, a burner is arranged, and after flame passes through a communication flue of the front hearth and the rear hearth, the direction of the flame is changed to burn upwards to form U-shaped flame; the overfire air (4) is arranged on the water cooling wall at the lower part of the rear hearth (3) after the turning of the communicating flue, is symmetrically arranged left and right and receives the radiation of high-temperature flame in the main combustion area; the front hearth (2) is subjected to anoxic combustion, the combustion temperature is low, and a reducing atmosphere is caused, so that the generation amount of fuel-type and thermal-type NOx is reduced; the rear hearth (3) is in oxygen-enriched combustion, so that a sufficient NOx reduction space is reserved, the burnout rate of coal dust is ensured, and the boiler efficiency is improved.
Description
Technical Field
The invention relates to a pulverized coal boiler technology, in particular to a U-shaped flame low-nitrogen combustion boiler.
Background
The small pulverized coal boiler is still in a starting stage in China, and has the problems of no load, high-temperature corrosion, high pollutant emission and the like due to poor matching of a combustion mode and a hearth structure, so that the small pulverized coal boiler cannot be well developed.
Although the fuel oil and gas boiler can well control the emission of pollutants, the fuel cost is too high, the coal is rich, the lean oil and the lean gas in China, and the coal is unavoidable as the main fuel. However, the market of small coal-fired boilers in China is mainly based on a layer combustion mode for a long time, the heat efficiency is low, the pollutant emission is high, and the small coal-fired boilers are gradually eliminated. The U-shaped flame low-nitrogen pulverized coal boiler has the advantages of high economic and environmental protection benefits, simple structure, easy manufacture and installation and convenient operation, can be designed into a hot water boiler and a steam boiler, can burn bituminous coal and difficult-to-burn lean coal and anthracite, has wide adaptability and has better market prospect. The invention relates to a U-shaped flame low-nitrogen pulverized coal boiler, and the background of the invention is derived from a large W-flame coal-fired boiler. For small pulverized coal boilers, a larger combustion space is required than in conventional grate-fired furnaces, which is similar to the problems faced by W-furnaces, which are mainly used for burning difficult coal. The W-type pulverized coal boiler with double shoulders has large occupied space, and the small pulverized coal boiler can completely adopt the hearth structure of the W-type pulverized coal boiler with single shoulders through calculation, so that the arrangement of a convection heating surface can be very compact while the combustion space is solved and the flame stroke is prolonged, and the U-type flame low-nitrogen combustion pulverized coal boiler is produced. For small pulverized coal boilers, the burner is usually arranged on the front wall, the furnace top or the bottom of the hearth, and a single hearth is usually adopted. These arrangements, limited by the furnace structure, cannot achieve reasonable air distribution, large thermal and fuel NOx production, insufficient flame stroke to cause the coal fines unable to burn out, resulting in low boiler efficiency, and at the same time, making the boiler difficult to reach rated load.
Disclosure of Invention
The invention aims to design a U-shaped flame low-nitrogen boiler which has enough pulverized coal combustion and burnout space and a reasonable aerodynamic field, can achieve rated load, avoid or reduce high-temperature corrosion, has low NOx emission and can reduce pollutant emission to the minimum level.
In order to achieve the purpose of the invention, the following technical scheme is adopted:
the utility model provides a U-shaped flame low nitrogen pulverized coal boiler, the furnace of pulverized coal boiler is two furnace designs, including preceding furnace 2, back furnace 3 and after fire wind 4, wherein,
the front hearth 2 is a main combustion area, the rear hearth 3 is an auxiliary combustion area and a burnout area, and the front hearth and the rear hearth are both composed of membrane water-cooled walls; the front hearth 2 is lower than the rear hearth 3 and is separated by a water cooling screen, and the lower parts of the front hearth 2 are communicated to form a U-shaped communicated flue;
the top of the front hearth 2 is provided with a certain inclination angle, a burner is arranged, and after flame passes through the communication flues of the front hearth and the front and rear hearths, the direction of the flame is changed to burn upwards in the rear hearth to form U-shaped flame;
the over-fire air 4 is arranged on the water cooling wall at the lower part of the rear hearth after the turning of the communicating flue and is symmetrically arranged left and right to receive the radiation of high-temperature flame in the main combustion area;
the front hearth 2 is a main combustion area of flame and is subjected to anoxic combustion, so that a reducing atmosphere is formed, and the generation amount of fuel NOx is reduced; the combustion temperature of the front hearth (2) is lower than 1500 ℃, so that the generation amount of thermal NOx is reduced; the rear hearth 3 is an auxiliary combustion area and is in oxygen-enriched combustion, so that the burnout rate of coal dust is ensured, and the boiler efficiency is improved.
The height of the over-fire air 4 from the hearth outlet meets the requirement that the over-fire time is more than 0.5 seconds, and the over-fire of coal dust is ensured.
The convection heating surface 6, the SCR7, the air preheater 8, the dust removal system and the desulfurization system are arranged in a convection area behind the pulverized coal boiler furnace. The convection heating surfaces 6 are each surrounded by a membrane wall.
Drawings
FIG. 1 is a schematic diagram of a U-flame low-nitrogen pulverized coal boiler.
Wherein:
1 burner, 2 front hearth, 3 rear hearth, 4 over-fire air
5 barrels, 6 convection heating surfaces, 7SCR and 8 air preheaters.
Detailed Description
The present invention will be further described in detail with reference to the drawings and the specific embodiments, in order to make the objects, technical solutions and advantages of the present invention more apparent.
FIG. 1 is a schematic diagram of a U-flame low-nitrogen pulverized coal boiler. As shown in the figure, the design principle of the U-shaped flame low-nitrogen pulverized coal boiler is as follows: the boiler furnace is of a double-furnace design, the front furnace is a main combustion zone, and the rear furnace is an auxiliary combustion zone and a burnout zone. The front hearth and the rear hearth are both composed of membrane water-cooled walls. The front hearth is lower than the rear hearth and is separated by a water cooling screen. The burner is positioned at the top of the front hearth with a certain inclination angle, and the flame is pushed downwards, and after passing through the communication flues of the front hearth and the rear hearth, the flame changes direction and enters the rear hearth to be burnt upwards, so that U-shaped flame is formed. And the water cooling wall at the lower part of the rear hearth after the turning of the communicating flue is provided with over-fire air. The high-temperature area of the flame is mainly in the front hearth under the action of the separation screen, and the high-temperature front hearth is subjected to anoxic combustion, so that the generation of thermal NOx is controlled; the overfire air is symmetrically arranged on the side water cooling wall at the rear lower part of the separation screen, the position can receive the radiation of high-temperature flame in the main combustion area, and meanwhile, the height of the overfire air from the hearth outlet meets the requirement of coal dust burnout (for example, the height of the overfire air from the hearth outlet meets the requirement of burnout time more than 0.5 seconds when the bituminous coal is burnt). The low-temperature rear hearth is in oxygen-enriched combustion, so that the burnout rate of coal dust is ensured, and the boiler efficiency is improved.
The novel U-shaped flame low-nitrogen pulverized coal boiler is characterized in that:
1. the front hearth and the rear hearth are arranged, and the front hearth is a main combustion area lower than the rear hearth; the rear hearth is an auxiliary combustion area and a burnout area; the front hearth and the rear hearth are separated by a water cooling screen;
2. the top of the front hearth is provided with a certain inclination angle, and the burner is arranged at the top of the front hearth;
3. the back hearth is provided with over-fire air;
4. the convection area behind the hearth is provided with a reasonable convection heating surface, SCR, an air preheater, a dust removal system and a desulfurization system;
5. the hearth is of a membrane water-cooled wall structure, the front convection heating surface of the SCR is surrounded by the membrane wall, and the front convection heating surface of the SCR is separated from the rear hearth by the membrane water-cooled wall, so that a furnace wall system of the whole boiler is simple;
6. the whole boiler is a supporting structure, and the supporting and hanging system is simple.
While the foregoing is directed to embodiments of the present invention, other and further details of the invention may be had by the present invention, it should be understood that the foregoing description is merely illustrative of the present invention and that no limitations are intended to the scope of the invention, except insofar as modifications, equivalents, improvements or modifications are within the spirit and principles of the invention.
Claims (3)
1. A U-shaped flame low-nitrogen pulverized coal boiler is characterized in that a hearth of the pulverized coal boiler is of a double-hearth design and comprises a front hearth (2), a rear hearth (3) and over-fire air (4), wherein,
the front hearth (2) is a main combustion area, the rear hearth (3) is an auxiliary combustion area and a burnout area, and the front hearth and the rear hearth are both composed of membrane water-cooled walls; the front hearth (2) is lower than the rear hearth (3) and is separated by a water cooling screen, and the lower parts of the front hearth are communicated to form a U-shaped communicated flue;
the top of the front hearth (2) is provided with a certain inclination angle, a burner is arranged, and after flame passes through a communication flue of the front hearth and a communication flue of the rear hearth, the direction of the flame is changed to burn upwards in the rear hearth to form U-shaped flame;
the overfire air (4) is arranged on the water cooling wall at the lower part of the rear hearth (3) after the turning of the communicating flue, is symmetrically arranged left and right and receives the radiation of high-temperature flame in the main combustion area;
the front hearth (2) is a main combustion zone of flame and is subjected to anoxic combustion, so that a reducing atmosphere is formed, and the generation amount of fuel NOx is reduced; the combustion temperature of the front hearth (2) is low, so that the generation amount of thermal NOx is reduced; the rear hearth (3) is an auxiliary combustion area and is in oxygen-enriched combustion, so that the burnout rate of coal dust is ensured, and the boiler efficiency is improved.
2. Pulverized coal boiler according to claim 1, characterized in that the combustion temperature of the front furnace (2) is lower than 1500 ℃, ensuring suppression of thermal NOx production; the height of the over-fire air (4) from the hearth outlet meets the requirement that the over-fire time is more than 0.5 seconds, and the over-fire of coal powder is ensured.
3. Pulverized coal boiler according to claim 2, characterized in that a convection heating surface (6), SCR (7), air preheater (8) and dust removal and desulfurization systems are arranged in a convection zone behind the pulverized coal boiler furnace, the convection heating surface (6) being surrounded by membrane walls.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710565536.1A CN109253447B (en) | 2017-07-12 | 2017-07-12 | U-shaped flame low-nitrogen pulverized coal boiler |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710565536.1A CN109253447B (en) | 2017-07-12 | 2017-07-12 | U-shaped flame low-nitrogen pulverized coal boiler |
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| Publication Number | Publication Date |
|---|---|
| CN109253447A CN109253447A (en) | 2019-01-22 |
| CN109253447B true CN109253447B (en) | 2024-01-30 |
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| CN113864766A (en) * | 2021-10-29 | 2021-12-31 | 山东建筑大学 | NO is arranged to U typeXUltra-low discharge pulverized coal boiler |
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| US5878700A (en) * | 1997-11-21 | 1999-03-09 | The Babcock & Wilcox Company | Integrated reburn system for NOx control from cyclone-fired boilers |
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| US5878700A (en) * | 1997-11-21 | 1999-03-09 | The Babcock & Wilcox Company | Integrated reburn system for NOx control from cyclone-fired boilers |
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