CN111561695A - Boiler flue gas and air system - Google Patents

Boiler flue gas and air system Download PDF

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Publication number
CN111561695A
CN111561695A CN202010429320.4A CN202010429320A CN111561695A CN 111561695 A CN111561695 A CN 111561695A CN 202010429320 A CN202010429320 A CN 202010429320A CN 111561695 A CN111561695 A CN 111561695A
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China
Prior art keywords
air
boiler
hearth
primary
flue gas
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CN202010429320.4A
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Chinese (zh)
Inventor
张中献
李振忠
于洋
郭蕾
刘刚
常艳梅
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SHENYANG DONGGUAN POWER TECHNOLOGY GROUP CO LTD
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SHENYANG DONGGUAN POWER TECHNOLOGY GROUP CO LTD
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Priority to CN202010429320.4A priority Critical patent/CN111561695A/en
Publication of CN111561695A publication Critical patent/CN111561695A/en
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    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23CMETHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN  A CARRIER GAS OR AIR 
    • F23C10/00Fluidised bed combustion apparatus
    • F23C10/18Details; Accessories
    • F23C10/20Inlets for fluidisation air, e.g. grids; Bottoms
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23LSUPPLYING 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
    • F23L1/00Passages or apertures for delivering primary air for combustion 
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23LSUPPLYING 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
    • F23L15/00Heating of air supplied for combustion
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23LSUPPLYING 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
    • F23L5/00Blast-producing apparatus before the fire
    • F23L5/02Arrangements of fans or blowers
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23LSUPPLYING 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
    • F23L9/00Passages or apertures for delivering secondary air for completing combustion of fuel 
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23MCASINGS, LININGS, WALLS OR DOORS SPECIALLY ADAPTED FOR COMBUSTION CHAMBERS, e.g. FIREBRIDGES; DEVICES FOR DEFLECTING AIR, FLAMES OR COMBUSTION PRODUCTS IN COMBUSTION CHAMBERS; SAFETY ARRANGEMENTS SPECIALLY ADAPTED FOR COMBUSTION APPARATUS; DETAILS OF COMBUSTION CHAMBERS, NOT OTHERWISE PROVIDED FOR
    • F23M5/00Casings; Linings; Walls
    • F23M5/08Cooling thereof; Tube walls
    • YGENERAL 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
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02EREDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E20/00Combustion technologies with mitigation potential
    • Y02E20/34Indirect 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)

Abstract

Boiler flue gas and air system belongs to boiler technical field, especially relates to a boiler flue gas and air system. The invention provides a boiler flue gas and air system. The invention includes the primary air blower 1, the secondary air blower 7, the high-pressure fluidizing air blower 8, characterized by that the wind outlet of the primary air blower 1 is divided into the first wind and second wind, the first wind is divided into boiler primary hot air and boiler start-up wind through the hot air duct 1.1 of the first wind after passing the air preheater 2 heating; primary hot air of the boiler enters the water cooling air chamber 4 through a primary air interface 1.3 of the boiler and enters a bed material layer 6.1 at the bottom of the hearth through a hood 4.1 of the hearth; the second path of air is cold air and flows to a feeding device 5 arranged in front of the furnace along a primary cold air channel 1.2; the secondary air fan 7 provides secondary air which is cold air and enters the dense-phase zone 6.2 of the hearth through a secondary air duct 7.1.

Description

Boiler flue gas and air system
Technical Field
The invention belongs to the technical field of boilers, and particularly relates to a boiler flue gas and air system.
Background
The social demand for energy is increasing and fossil fuels, which are major energy sources, are rapidly decreasing. Therefore, the search for a renewable alternative energy source becomes a focus of general social attention. Biomass is the only renewable energy source which can be directly stored and transported, and circulating fluidized bed boilers which use biomass for power generation are widely used.
The biomass fuel has obvious seasonality, regionality and diversity, and the existing biomass circulating fluidized bed boiler unit has poor material fluidity, uneven distribution of the left side and the right side of boiler smoke and air, difficult smoke temperature regulation, low boiler efficiency and overproof emission during operation, and influences the safe, stable and economic operation of the boiler.
Disclosure of Invention
The invention aims at the problems and provides a boiler flue gas and air system.
In order to achieve the purpose, the invention adopts the following technical scheme that the high-pressure fluidized bed comprises a primary fan 1, a secondary fan 7 and a high-pressure fluidized fan 8, and is characterized in that the air outlet of the primary fan 1 is divided into a first path of air and a second path of air, the first path of air is heated by an air preheater 2 and then is divided into primary hot air of a boiler and air for starting the boiler by a primary hot air channel 1.1;
primary hot air of the boiler enters the water cooling air chamber 4 through a primary air interface 1.3 of the boiler and enters a bed material layer 6.1 at the bottom of the hearth through a hood 4.1 of the hearth;
the second path of air is cold air and flows to a feeding device 5 arranged in front of the furnace along a primary cold air channel 1.2;
the secondary air fan 7 provides secondary air which is cold air and enters the dense-phase region 6.2 of the hearth through a secondary air duct 7.1;
the high pressure fluidizing fan 8 provides high pressure fluidizing air which enters the lower air chamber 9 of the return feeder through a high pressure fluidizing air duct 8.1 and then enters the return area 10 through a return feeder hood 9.1.
Preferably, the start-up air of the boiler according to the present invention includes an ignition air for igniting the oil of the start-up burner 3 and a mixed air for controlling the temperature of the flue gas after the oil is burned during the start-up.
As another preferred scheme, the primary air interface 1.3 is arranged at the first end of the three-way pipe, the second end of the three-way pipe is connected with the water cooling air chamber 4 at the lower end of the hearth 6, and the third end of the three-way pipe is connected with the starting burner 3.
As another preferred scheme, the outlet of the primary air fan 1 is divided into a first path of air and a second path of air through a three-way pipe.
As another preferable scheme, the second air enters the feeding device 5 and is divided into sealing air and broadcasting air, the sealing air is connected to the feeding device 5 through a sealing air connector 5.1, and the broadcasting air is connected to the lower part of a connecting pipeline between the feeding device 5 and the lower part of the second end hearth 6 through a broadcasting air connector 5.2.
As another preferred scheme, the secondary air duct 7.1 of the invention enters an upper secondary air wind box 7.2 and a lower secondary air wind box 7.4 which are arranged around the middle lower part of the hearth 6 respectively, and then enters the middle upper part of the dense-phase area 6.2 of the hearth through a plurality of upper secondary air nozzles 7.3 and lower secondary air nozzles 7.5 which are uniformly arranged along the front water-cooled wall and the rear water-cooled wall of the hearth respectively.
Secondly, the upper secondary air nozzle 7.3 and the lower secondary air nozzle 7.5 are arranged at intervals.
In addition, the furnace top at the upper end of the hearth 6 is rotated and transversely extends to pass through a hearth flue gas outlet to be connected with an inlet of a heat-insulating cyclone separator 11, a feed back region 10 is arranged at the lower end of the heat-insulating cyclone separator 11, the lower part of the heat-insulating cyclone separator 11 is connected with the upper end of a feed back inclined pipe 12, and the lower end of the feed back inclined pipe 12 is connected with the lower part of the hearth 6;
the upper end center barrel 13 of the cyclone separator 11 is connected with the upper end of a vertical convection flue 14, and the lower end of the vertical convection flue 14 enters a chimney through a dust removal device 15 and an induced draft fan 16.
The invention has the beneficial effects.
The invention adjusts the air quantity through the opening of the fan baffle.
The invention adopts the furnace blast cap, has better fuel adaptability and uniform distribution of boiler smoke and air.
The invention adopts a graded air supply mode (primary air and secondary air), can effectively inhibit the generation of NOx and reduce the generation amount of NOx in the combustion process.
Drawings
The invention is further described with reference to the following figures and detailed description. The scope of the invention is not limited to the following expressions.
FIG. 1 is a schematic view of a boiler flue gas system according to the present invention.
FIG. 2 is a schematic view of the air distribution structure of the hearth of the invention.
Fig. 3 is a top view of fig. 1 (only the furnace and the return valve are shown).
Fig. 4 is a schematic view of the blast cap mounting arrangement.
Fig. 5 is a sectional view a-a of fig. 4.
FIG. 6 is a schematic view of a furnace hood at a slag discharge port of a water-cooled air distribution plate.
In fig. 1: the system comprises a primary fan 1, a primary hot air duct 1.1, a primary cold air duct 1.2, a primary air interface 1.3, an air preheater 2 and a starting burner 3;
the furnace comprises a water-cooling wind chamber 4, a water-cooling wind distribution plate 4.1, a wear-resistant refractory castable 4.11, a slag discharge port 4.12, a hearth hood 4.2, an air inlet pipe 4.21, a hood outer cover 4.22, an air outlet 4.23, an air inlet bent pipe 4.24, an air inlet hole 4.25, a hood sleeve 4.26, a top wind chamber membrane wall 4.3, membrane wall flat steel 4.4 and a membrane wall pipe 4.5;
the device comprises a feeding device 5, a sealing air interface 5.1 and a seeding air interface 5.2;
a hearth 6, a hearth bottom bed material layer 6.1, a hearth dense-phase region 6.2, a hearth front wall 6.3 and a hearth rear wall 6.4;
a secondary air fan 7, a secondary air duct 7.1, an upper secondary air bellow 7.2, an upper secondary air nozzle 7.3, a lower secondary air bellow 7.4 and a lower secondary air nozzle 7.5;
the device comprises a high-pressure fluidization fan 8, a high-pressure fluidization air duct 8.1, a material returning device lower air chamber 9, a material returning device hood 9.1, a material returning area 10, a cyclone separator 11, a material returning inclined pipe 12, a separator central cylinder 13, a convection flue 14, a dust removing device 15 and an induced draft fan 16.
Detailed Description
As shown in the figure, the high-pressure fluidized bed boiler comprises a primary fan 1, a secondary fan 7 and a high-pressure fluidized fan 8, wherein air at the outlet of the primary fan 1 is divided into first air and second air, the first air is heated by an air preheater 2 and then is divided into primary hot air of the boiler and air for starting the boiler through a primary hot air channel 1.1;
primary hot air of the boiler enters the water cooling air chamber 4 through a primary air interface 1.3 of the boiler and enters a bed material layer 6.1 at the bottom of the hearth through a hearth hood 4.2;
the second path of air is cold air and flows to a feeding device 5 arranged in front of the furnace along a primary cold air channel 1.2;
the secondary air fan 7 provides secondary air which is cold air and enters the dense-phase region 6.2 of the hearth through a secondary air duct 7.1;
the high pressure fluidizing fan 8 provides high pressure fluidizing air which enters the lower air chamber 9 of the return feeder through a high pressure fluidizing air duct 8.1 and then enters the return area 10 through a return feeder hood 9.1.
The start-up air of the boiler includes ignition air for oil ignition of the start-up burner 3 and mixed air for controlling the temperature of flue gas after oil combustion during start-up.
The primary air interface 1.3 is arranged at the first end of the three-way pipe, the second end of the three-way pipe is connected with the water cooling air chamber 4 at the lower end of the hearth 6, and the third end of the three-way pipe is connected with the starting burner 3.
The outlet of the primary air fan 1 is divided into a first path of air and a second path of air through a three-way pipe.
The second path of wind enters the feeding device 5 and is divided into sealing wind and broadcasting wind, the sealing wind is connected into the feeding device 5 through a sealing wind connector 5.1, and the broadcasting wind is connected into the lower part of a connecting pipeline between the feeding device 5 and the lower part of the second end-connected hearth 6 through a broadcasting wind connector 5.2.
The secondary air duct 7.1 respectively enters an upper secondary air box 7.2 and a lower secondary air box 7.4 which are arranged on the periphery of the middle lower part of the hearth 6, and then respectively enters the middle and upper parts of a dense-phase area 6.2 of the hearth through a plurality of upper secondary air nozzles 7.3 and lower secondary air nozzles 7.5 which are uniformly arranged along the front and rear water-cooled walls of the hearth.
The upper secondary air nozzle 7.3 and the lower secondary air nozzle 7.5 are arranged at intervals (the central line of the upper secondary air nozzle 7.3 is arranged, and two sides of the central line of the lower secondary air nozzle 7.5 are arranged).
The furnace top at the upper end of the hearth 6 is rotated and transversely extends to be connected with an inlet of a heat-insulating cyclone separator 11 through a hearth flue gas outlet, a feed back region 10 is arranged at the lower end of the heat-insulating cyclone separator 11, the lower part of the heat-insulating cyclone separator 11 is connected with the upper end of a feed back inclined pipe 12, and the lower end of the feed back inclined pipe 12 is connected with the lower part of the hearth 6;
the upper end center barrel 13 of the cyclone separator 11 is connected with the upper end of a vertical convection flue 14, and the lower end of the vertical convection flue 14 enters a chimney through a dust removal device 15 and an induced draft fan 16.
A superheater, a reheater, an economizer, and an air preheater may be disposed in the convection flue 14.
And a screen type superheater is arranged at the upper end of the hearth 6. The platen superheater can be used as a heating surface to generate steam, and the steam is output through a pipeline.
The primary air system is supplied with air by a primary air fan 1, the air at the outlet of the primary air fan 1 is divided into two paths of air, one path of air is heated by an air preheater 2 to become hot air, and the hot air is divided into primary hot air of a boiler and air for starting the boiler through a primary hot air channel 1.1.
Primary hot air of the boiler enters the water cooling air chamber 4 through a primary air interface 1.3 of the boiler and enters a bed material layer 6.1 at the bottom of the hearth through a hood 4.2 of the hearth, so that fluidization of materials of the hearth and ignition and combustion supporting of auxiliary fuel are realized. During boiler firing, this path wind shut-off is replaced by start-up wind.
The starting air of the boiler is divided into ignition air and mixed air. The boiler is started and is used wind through starting the burner 3, the wind of igniting is used for starting the oil ignition of the burner 3, mix the wind and be used for controlling the flue gas temperature after the oil combustion during starting. When the boiler normally operates, the air is closed.
The other path of primary air is cold air and flows to a feeding device 5 arranged in front of the furnace along a primary cold air channel 1.2. The path of air is divided into sealing air and broadcasting air before entering the feeding device 5, the sealing air is accessed through a sealing air interface 5.1, smoke in a hearth is prevented from returning and fleeing, and a feeding system is protected; the seeding air is connected through a seeding air interface 5.2 to assist the biomass fuel to smoothly enter the hearth 6 for combustion.
The secondary air system air is provided by a secondary air fan 7. The secondary air is cold air and respectively enters an upper secondary air box 7.2 and a lower secondary air box 7.4 which are arranged on the periphery of the hearth through a secondary air duct 7.1, the secondary air respectively enters the middle part and the upper part of a dense phase area 6.2 of the hearth through a plurality of upper secondary air nozzles 7.3 and lower secondary air nozzles 7.5 which are uniformly arranged along the front water-cooled wall and the rear water-cooled wall of the hearth, and the upper secondary air nozzles 7.3 and the lower secondary air nozzles 7.5 are arranged at intervals, so that combustion supporting of fuel is facilitated.
The temperature of the hearth can be controlled by adjusting the proportion of the primary air volume and the secondary air volume to participate in combustion adjustment during operation. Meanwhile, the graded air supply can create local reducing atmosphere in the furnace, thereby inhibiting nitrogen oxidation in the fuel and reducing the generation of nitrogen oxides NOx.
High-pressure fluidizing air provided by a high-pressure fluidizing fan 8 enters a lower air chamber 9 of a return feeder through a high-pressure fluidizing air duct 8.1 and respectively enters a blanking area and a return area of a return area 10 through a return feeder hood 9.1 to realize fluidization of materials in the return area 10 and self-sealing of the return area 10, and the return feeder hood 9.1 and a hearth hood 4.2 can adopt the same structural form.
And (3) distributing the air quantity of the boiler:
Figure BDA0002499940700000061
when the boiler operates, the biomass fuel generates high-temperature flue gas after being combusted in a hearth, carries a large amount of bed materials in the boiler to turn through the top of the boiler, enters a heat-insulating cyclone separator 11 through a flue gas outlet of the hearth for gas-solid two-phase separation, most of particles are separated, and are returned to the lower part of the hearth 6 through a material returning area 10 and a material returning inclined pipe 12 which are arranged below the separator 11,
the separated flue gas containing a small amount of fly ash is led out from a central cylinder 13 of the separator, enters a tail convection flue 14, exchanges heat with heating surfaces such as a superheater, a reheater, an economizer, an air preheater and the like arranged in the tail convection flue, reaches the designed exhaust gas temperature after reaching the tail outlet of the boiler, and then enters a chimney through a dust removal device 15 and a draught fan 16 to be exhausted to the atmosphere.
The invention is suitable for the biomass circulating fluidized bed boiler.
As shown in fig. 2-6, the air distribution structure of the hearth 6 comprises a primary hot air duct 1.1, the primary hot air duct 1.1 is connected with an inlet of a water-cooling air chamber 4, and an outlet of the water-cooling air chamber 4 is connected with a hearth material layer at the bottom of the hearth through a hearth hood 4.2 on a water-cooling air distribution plate 4.1; a slag discharge port 4.12 is arranged on the water-cooling air distribution plate 4.1;
the water-cooling air distribution plate 4.1 is based on a top air chamber membrane wall 4.3 of the water-cooling air chamber 4, holes are uniformly formed in the membrane wall flat steel 4.4, and hearth air caps 4.2 are welded on the holes.
According to the invention, primary air enters the water-cooling air chamber 4 through the primary hot air duct 1.1, flows through the hearth hood 4.2 on the water-cooling air distribution plate 4.1 and enters a bed material layer at the bottom of the hearth, so that the uniform fluidization of materials in the hearth is realized, and the combustion efficiency of the boiler is improved.
According to the invention, the air distribution structure is adopted to improve the air supply of the hearth of the biomass garbage circulating fluidized bed boiler, the bed resistance is uniform, the bed material agglomeration and layered fluidization are avoided, the fluidization uniformity is ensured, and the safe, stable and economic operation of the boiler is ensured.
The upper end surface of the water-cooling air distribution plate 4.1 is provided with a hearth front wall 6.3 and a hearth rear wall 6.4 which are high, the center line of the hearth is low, and the included angle gamma between the upper end surface and the horizontal plane is 3-4 degrees; and arranging the furnace blast caps 4.2 according to the height trend.
The furnace blast caps 4.2 are arranged in parallel at equal intervals, and the included angle alpha between the air outlet holes 4.23 and the central connecting line of the furnace blast caps 4.2 is 40-45 degrees.
Along the water-cooling air distribution plate 4.1 with an inclined structure, the hearth hood 4.2 is integrally arranged according to a hearth front wall 6.3, a hearth rear wall 6.4 is high, and the hearth central line is low in step arrangement, meanwhile, when each hearth hood 4.2 is installed, the hearth hoods are arranged in sequence at equal intervals, the included angle alpha between the air outlet 4.23 and the central line of the hearth hood 4.2 is 40-45 degrees, so that primary air flow forms an even power field, and the whole water-cooling air distribution plate 4.1 is ensured to realize even and stable fluidization of bed materials and meet the requirement of normal combustion of fuel entering a furnace.
The downward inclination angle beta of the air outlet hole 4.23 is 6-10 degrees.
The furnace hood 4.2 adopts a bell jar type, a hood outer cover 4.22 is welded at the top of the air inlet pipe 4.21, a plurality of air inlet holes 4.25 are formed along the circumference of the upper part of the air inlet pipe 4.21, and air outlet holes 4.23 are formed along the circumference of the lower part of the hood outer cover 4.22; the downward inclination angle beta of the air outlet hole 4.23 is 6-10 degrees, so that the air distribution plate is prevented from being directly swept by air flow, and meanwhile, the air cap is ensured not to block ash and leak slag. Each furnace hood 4.2 is provided with four air outlet holes 4.23 arranged along the circumferential direction.
And a wear-resistant refractory castable layer 4.11 is laid between the top plenum diaphragm wall 4.3 and the hood outer cover 4.22.
The furnace hood 4.2 adopts a bell jar type, a hood outer cover 4.22 is welded at the top of the air inlet pipe 4.21, a plurality of air inlet holes 4.25 are formed along the circumference of the upper part of the air inlet pipe 4.21, and air outlet holes 4.23 are formed along the circumference of the lower part of the hood outer cover 4.22;
the lower part of the air inlet pipe 4.21 is sleeved with a blast cap sleeve 4.26, and a 1-2 mm gap is reserved between the air inlet pipe 4.21 and the blast cap sleeve 4.26 so as to counteract the influence of the thermal expansion of the water wall on the blast cap 4.2 of the hearth; the lower end of the blast cap sleeve 4.26 is welded with the membrane wall flat steel 4.4, and the upper end is welded with the blast pipe 4.21.
The water-cooling air distribution plate 4.1 is based on a top air chamber membrane wall 4.3 of the water-cooling air chamber 4, holes are uniformly formed in the membrane wall flat steel 4.4, and hearth air caps 4.2 are welded on the holes. By adopting the structure, no extra plate is needed, and only the hearth hood 4.2 is arranged at the upper end of the water-cooling air chamber 4. The membrane wall tube 4.5 is arranged between the adjacent membrane wall flat steels 4.4, and the membrane wall flat steel 4.4 is arranged in the middle of the membrane wall tube 4.5 in the height direction.
A wear-resistant refractory castable layer 4.11 is laid between the top plenum diaphragm wall 4.3 and the hood outer cover 4.22; the water-cooling air distribution plate 4.1 is not abraded by bed materials, materials and ash residues.
The air inlet 4.25 is upper and lower two circles, staggered arrangement, and the air inlet is more even.
Two slag outlets 4.12 are symmetrically arranged on the water-cooling air distribution plate 4.1 along the central line of the hearth at two sides of the width direction of the hearth (the slag outlets 4.12 are connected with a vertical pipeline, and the vertical pipeline penetrates through the water-cooling air chamber 4).
2 slag outlets 4.12 are symmetrically arranged on the water-cooling air distribution plate 4.1 along the central line of the hearth, and are matched with the water-cooling air distribution plate 4.1 which is arranged on the front wall 6.3 of the hearth on the upper end surface, the rear wall 6.4 of the hearth and is lower on the central line of the hearth; the slag is conveniently and smoothly discharged, the risk that the air distribution plate is damaged once the slag blocking occurs at the centralized large slag hole can be eliminated, meanwhile, the 2 slag holes 4.12 are symmetrically arranged, the cross section area of each slag hole can be correspondingly reduced, and the weakening of the centralized large slag hole to the integral strength of the air distribution plate is reduced.
The hearth hood 4.2 arranged around the slag discharge port 4.12 adopts an air inlet bent pipe 4.24 structure, the upper part of the air inlet bent pipe 4.24 is a vertical pipe, and the lower end of the vertical pipe is bent outwards and downwards. Make up the top plenum diaphragm wall 4.3 because of opening the slag discharge 4.12 lets the pipe, reduce to arrange furnace hood 4.2, be favorable to the air distribution even, improve boiler combustion efficiency.
The horizontal sectional area of the water-cooling air distribution plate 4.1 can be obviously smaller than that of the upper part of the hearth 6 (namely, the longitudinal section of the hearth 6 is a reversed trapezoid with a large upper part and a small lower part).
The primary air quantity can be adjusted to ensure that the primary air quantity through the water-cooling air distribution plate 4.1 accounts for 45-50% of the total air quantity of the boiler, and the fluidization of bed materials in the boiler is enhanced.
It should be understood that the detailed description of the present invention is only for illustrating the present invention and is not limited by the technical solutions described in the embodiments of the present invention, and those skilled in the art should understand that the present invention can be modified or substituted equally to achieve the same technical effects; as long as the use requirements are met, the method is within the protection scope of the invention.

Claims (8)

1. The boiler smoke and air system comprises a primary fan (1), a secondary fan (7) and a high-pressure fluidized fan (8), and is characterized in that air at the outlet of the primary fan (1) is divided into first air and second air, the first air is heated by an air preheater (2) and then divided into primary hot air of a boiler and air for starting the boiler through a primary hot air channel (1.1);
primary hot air of the boiler enters a water cooling air chamber (4) through a primary air interface (1.3) of the boiler and enters a bed material layer (6.1) at the bottom of a hearth through a hearth hood (4.1);
the second path of air is cold air and flows to a feeding device (5) arranged in front of the furnace along the primary cold air channel (1.2);
the secondary air is provided by the secondary fan (7), the secondary air is cold air, and enters the dense-phase region (6.2) of the hearth through a secondary air duct (7.1);
adjusting the air quantity through a fan;
the temperature of the hearth is controlled by adjusting the proportion of the primary air and the secondary air to participate in combustion adjustment.
2. The boiler flue gas system according to claim 1, wherein the start-up air of the boiler comprises an ignition air for starting oil ignition of the burner (3) and a mixed air for controlling a flue gas temperature after oil combustion during start-up.
3. The boiler flue gas air system according to claim 1, characterized in that the primary air interface (1.3) is arranged at a first end of a three-way pipe, a second end of the three-way pipe is connected with a water cooling air chamber (4) at the lower end of the hearth (6), and a third end of the three-way pipe is connected with the start-up burner (3).
4. The boiler flue gas system according to claim 1, wherein the outlet of the primary air fan (1) is divided into a first path of air and a second path of air by a three-way pipe.
5. The boiler flue gas system according to claim 1, wherein the second path of air is divided into sealing air and seeding air when entering the feeding device (5), the sealing air is connected into the feeding device (5) through a sealing air connector (5.1), and the seeding air is connected into the lower part of a connecting pipeline between the feeding device (5) and the lower part of the second end-connected hearth (6) through a seeding air connector (5.2).
6. The boiler flue gas system according to claim 1, wherein the secondary air duct (7.1) enters an upper secondary air box (7.2) and a lower secondary air box (7.4) which are respectively arranged around the middle lower part of the furnace (6), and then enters the middle upper part and the upper part of the dense-phase area (6.2) of the furnace through a plurality of upper secondary air nozzles (7.3) and lower secondary air nozzles (7.5) which are respectively and uniformly arranged along the front water wall and the rear water wall of the furnace.
7. The boiler flue gas system according to claim 6, wherein the upper secondary air nozzle (7.3) and the lower secondary air nozzle (7.5) are arranged at a distance.
8. The boiler flue gas system according to claim 3, characterized in that the upper end of the furnace (6) is provided with a furnace top which turns to transversely extend through a furnace flue gas outlet and is connected with an inlet of an insulated cyclone separator (11), the lower end of the insulated cyclone separator (11) is provided with a feed back area (10), the lower part of the insulated cyclone separator (11) is connected with the upper end of a feed back inclined pipe (12), and the lower end of the feed back inclined pipe (12) is connected with the lower part of the furnace (6);
a central cylinder (13) at the upper end of the cyclone separator (11) is connected with the upper end of a vertical convection flue (14), and the lower end of the vertical convection flue (14) enters a chimney through a dust removal device (15) and an induced draft fan (16).
CN202010429320.4A 2020-05-20 2020-05-20 Boiler flue gas and air system Pending CN111561695A (en)

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Application publication date: 20200821