CN116146973A - Low-level arrangement high-efficiency boiler system with desulfurization and denitrification circulating fluidized bed in furnace - Google Patents

Low-level arrangement high-efficiency boiler system with desulfurization and denitrification circulating fluidized bed in furnace Download PDF

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Publication number
CN116146973A
CN116146973A CN202211689149.6A CN202211689149A CN116146973A CN 116146973 A CN116146973 A CN 116146973A CN 202211689149 A CN202211689149 A CN 202211689149A CN 116146973 A CN116146973 A CN 116146973A
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China
Prior art keywords
desulfurization
outlet end
flue
hearth
secondary air
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Chinese (zh)
Inventor
降东方
李云龙
李志远
贾维新
徐慧
刘介东
赵岩
刘婷
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Harbin Hongguang Boiler General Factory Co ltd
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Harbin Hongguang Boiler General Factory Co ltd
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Priority to CN202211689149.6A priority Critical patent/CN116146973A/en
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    • 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 
    • F23C10/00—Fluidised bed combustion apparatus
    • F23C10/02—Fluidised bed combustion apparatus with means specially adapted for achieving or promoting a circulating movement of particles within the bed or for a recirculation of particles entrained from the bed
    • F23C10/04—Fluidised bed combustion apparatus with means specially adapted for achieving or promoting a circulating movement of particles within the bed or for a recirculation of particles entrained from the bed the particles being circulated to a section, e.g. a heat-exchange section or a return duct, at least partially shielded from the combustion zone, before being reintroduced into the combustion zone
    • F23C10/08—Fluidised bed combustion apparatus with means specially adapted for achieving or promoting a circulating movement of particles within the bed or for a recirculation of particles entrained from the bed the particles being circulated to a section, e.g. a heat-exchange section or a return duct, at least partially shielded from the combustion zone, before being reintroduced into the combustion zone characterised by the arrangement of separation apparatus, e.g. cyclones, for separating particles from the flue gases
    • F23C10/10—Fluidised bed combustion apparatus with means specially adapted for achieving or promoting a circulating movement of particles within the bed or for a recirculation of particles entrained from the bed the particles being circulated to a section, e.g. a heat-exchange section or a return duct, at least partially shielded from the combustion zone, before being reintroduced into the combustion zone characterised by the arrangement of separation apparatus, e.g. cyclones, for separating particles from the flue gases the separation apparatus being located outside the combustion chamber
    • 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 
    • F23C10/00—Fluidised bed combustion apparatus
    • F23C10/18—Details; Accessories
    • 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 
    • F23C10/00—Fluidised bed combustion apparatus
    • F23C10/18—Details; Accessories
    • F23C10/20—Inlets for fluidisation air, e.g. grids; Bottoms
    • 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 
    • F23C10/00—Fluidised bed combustion apparatus
    • F23C10/18—Details; Accessories
    • F23C10/22—Fuel feeders specially adapted for fluidised bed combustion apparatus
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES 
    • F23J15/00—Arrangements of devices for treating smoke or fumes
    • F23J15/003—Arrangements of devices for treating smoke or fumes for supplying chemicals to fumes, e.g. using injection devices
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES 
    • F23J15/00—Arrangements of devices for treating smoke or fumes
    • F23J15/006—Layout of treatment plant
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES 
    • F23J15/00—Arrangements of devices for treating smoke or fumes
    • F23J15/02—Arrangements of devices for treating smoke or fumes of purifiers, e.g. for removing noxious material
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES 
    • F23J15/00—Arrangements of devices for treating smoke or fumes
    • F23J15/06—Arrangements of devices for treating smoke or fumes of coolers

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Fluidized-Bed Combustion And Resonant Combustion (AREA)

Abstract

A low-level arrangement high-efficiency in-furnace desulfurization and denitrification circulating fluidized bed boiler system relates to a circulating fluidized bed boiler system. The invention aims to solve the problem that the ultra-low emission and the high energy efficiency of the existing circulating fluidized bed boiler are difficult to realize together. The invention comprises a hearth, a separator, a top flue, a dust collector, an induced draft fan, a chimney, a water-cooled air chamber, a coal feeding pipe, a lower coal feeding pipe, a tail flue, a plurality of secondary air pipes, a plurality of front side wall secondary air port desulfurization pipes and a plurality of rear side wall secondary air port desulfurization pipes, wherein one side of the coal feeding pipe is connected with the lower coal feeding pipe, the outlet end of the secondary air pipe is connected with the lower part of the hearth, the outlet end of the secondary air pipe arranged on the front side wall of the hearth is connected with the front side wall secondary air port desulfurization pipe, and the outlet end of the secondary air pipe arranged on the rear side wall of the hearth is connected with the rear side wall secondary air port desulfurization pipe. The invention is used for boiler combustion.

Description

Low-level arrangement high-efficiency boiler system with desulfurization and denitrification circulating fluidized bed in furnace
Technical Field
The invention relates to a circulating fluidized bed boiler system, in particular to a low-level arrangement high-efficiency in-furnace desulfurization and denitrification circulating fluidized bed boiler system.
Background
The energy distribution characteristics of China determine that coal is still the dominant force for a long time, and the ratio of the coal in various energy types is up to more than 50%. Along with the continuous improvement of the proportion of new energy sources such as solar energy, wind energy, hydrogen energy and the like, coal still plays an important role in bottom conservation and peak shaving continuously.
Circulating fluidized bed boilers are currently mainstream products applied to the market of coal-fired boilers, and on the basis of the traditional advantages of the circulating fluidized bed boilers, the investment of environmental protection systems is increased along with the increasing strictness of national environmental protection policies. Based on the scientific development concepts of energy conservation, emission reduction and environmental protection, the boiler design is required to have high thermal efficiency and SO (sulfur dioxide) 2 The emission of pollutants such as NOx, dust and the like is low.
The main characteristics of the circulating fluidized bed boiler are that the original emission of NOx is low, the desulfurization cost in the boiler is relatively low, and SCR denitration equipment, semi-dry method or wet method desulfurization equipment are arranged at the tail part of the conventional boiler. For high volatile fuels, the current industry is leading the state of the artCan control the initial emission of NOx to 55-120mg/Nm 3 Some products achieve the goal of low initial NOx emissions by "sacrificing" partial combustion efficiency, such as by lowering bed temperature, some products are up to 200mg/Nm 3 Above, the SNCR and the tail SCR in the furnace must be put into operation simultaneously to ensure that the NOx reaches the emission standard; for dry desulfurization of limestone in a furnace, the common desulfurization efficiency of the technical level in the industry is 70-90%, and SO can be achieved only by throwing equipment such as wet desulfurization at the tail part 2 Reaching the standard.
Disclosure of Invention
The invention aims to solve the problem that the ultra-low emission and the high energy efficiency of the existing circulating fluidized bed boiler are difficult to realize together, and further provides a low-level arrangement high-efficiency in-furnace desulfurization and denitrification circulating fluidized bed boiler system.
The technical scheme adopted for solving the technical problems is as follows:
the utility model provides a desulfurization denitration circulating fluidized bed boiler system in low level arrangement high-efficient stove includes furnace, the separator, the top flue, the dust collector, the draught fan, the chimney, the water-cooling plenum, the coal feed pipe is broadcast coal wind desulfurization pipeline of low level, coal feed pipe is broadcast coal wind pipeline, the afterbody flue, a plurality of overgrate air pipes, a plurality of preceding side wall overgrate air mouth desulfurization pipeline and a plurality of back side wall overgrate air mouth desulfurization pipeline, the air-out end of water-cooling plenum is connected with the lower part entrance point of furnace, be equipped with the distributor plate on the lower part entrance point of furnace, the exit end of coal feed pipe is connected with one side of furnace lower part, the exit end of coal feed pipe is connected with coal feed pipe and is broadcast coal wind desulfurization pipeline, one side of coal feed pipe is connected with the lower side coal feed pipe and is broadcast coal wind desulfurization pipeline, a plurality of overgrate air pipes are equispaced in the outside of furnace along circumference direction, the exit end of overgrate air pipe is connected with the lower part of furnace, and the exit end setting of overgrate air pipe is in the upper portion of overgrate air pipe exit end, the export end of overgrate air pipe is connected with the front side wall's the overgrate air pipe's that is connected with the inlet of furnace's the separator, the top of the separator is connected with the top of the inlet of the flue of the top of the flue is connected to the top of the separator of the back end of the flue, the dust collector is connected with the top of the dust collector of the top of the dust collector, the dust collector is connected with the top of the dust collector.
Further, a tail heating surface is arranged in the middle of the tail flue.
Further, the lower part of the tail flue is provided with an air preheater.
Further, the separator comprises a barrel, a central barrel and an inlet flue, wherein the inlet end of the inlet flue is connected with the upper outlet end of the hearth, the outlet end of the inlet flue is connected with the upper inlet end of the barrel, the inlet end of the central barrel is connected with the top flue gas outlet end of the barrel, the outlet end of the central barrel is connected with the inlet end of the top flue, the powder outlet end of the lower end of the barrel is connected with the upper inlet end of a returning leg, and the lower outlet end of the returning leg is connected with the lower part of the hearth.
Further, the inlet flue is of a full-declining step-free structure, and the inlet flue is arranged in a downward inclined mode from the inlet end to the outlet end.
Further, an SNCR denitration system is arranged at the inlet end of the inlet flue.
Further, the SNCR denitration system comprises two groups of spray guns, wherein a group of spray guns are arranged on the inner side and the outer side of the inlet end of the inlet flue, and each group of spray guns comprises a plurality of spray guns which are arranged in a staggered mode.
Further, the center lines of the central cylinder and the cylinder body are eccentrically arranged.
Further, the top end surface of the hearth is arranged in a downward inclined manner from the side of the outlet end to the other side.
Further, the top flue is arranged in a downward inclined manner along the inlet end to the outlet end.
Compared with the prior art, the invention has the following beneficial effects:
1. the invention provides a low-level arranged high-efficiency in-furnace desulfurization and denitrification circulating fluidized bed boiler system, which is characterized in that for low-sulfur coal (Sar < 1) in an industrial boiler, combustion is controlled from a source optimization structure so as to inhibit generation of nitrogen oxides, original emission of the nitrogen oxides is reduced, urea or ammonia water is sprayed into a SNCR denitrification system arranged at an inlet of a separator for further denitrification, and thus the ultra-low emission requirement can be met; the low-level arrangement high-efficiency in-furnace desulfurization technology is adopted, so that the in-furnace desulfurization efficiency is improved, sulfur dioxide can reach the ultralow emission standard when Ca/S is 1.5-2, the boiler efficiency under the low Ca/S desulfurization working condition can be improved, and the negative influence of desulfurization on low nitrogen is weakened. Compared with the conventional boiler, the tail part of the boiler can completely cancel desulfurization equipment and denitration (SCR) equipment, only a bag-type dust collector is reserved, the investment of environmental protection engineering and corresponding management and operation cost are greatly reduced, the boiler efficiency can be greatly improved, and the double-excellent performance of ultralow emission and high energy efficiency is realized.
2. Full declination step-free efficient adiabatic separator technology: the inlet flue of the separator adopts an innovative full declining structure, the declining angle is 9.5 degrees, the step at the joint of the declining section and the top of the separator cylinder body is cancelled, the higher flue gas inlet flow velocity (more than or equal to 30 m/s), the longer inlet accelerating section (more than or equal to 3 m) of the separator and the reasonable eccentric size of the central cylinder are selected, the flue gas flow field is optimized, the efficiency of the separator is further improved, superfine circulating ash particles d50 of 52.8 mu m are obtained, the circulating ash particle size is reduced, the reducing atmosphere of a dense-phase area is enhanced, the generation amount of NOx is reduced, and the residence time and the circulating times of fine particle fuel and limestone powder are increased, so that the combustion efficiency and the desulfurization efficiency are improved.
3. An efficient in-furnace desulfurization technology: the novel coal feeding port coal feeding air pipe leading-out branch pipe is used as the thought of lime powder spraying interface and low-level arrangement of the calcium spraying interface, and compared with the structure of high-level arrangement such as a secondary air pipe and a material returning leg, lime powder and coal can be mixed earlier in time and better in space, meanwhile, the flue gas pressure in the coal feeding pipe area is higher, the back pressure of lime powder conveying air entering a boiler can be improved, the penetrating power of the lime powder conveying air is improved, a reasonable temperature field and an optimized oxygen amount field are designed, a new and improved in-furnace desulfurization reaction and combustion reaction double-coupling algorithm is applied, the heating surface structure and area arrangement are optimized, and SO can be realized when Ca/S is 1.5-2 2 The method can reach the ultra-low emission standard, can improve the boiler efficiency under the low Ca/S desulfurization working condition, and weaken the negative influence of desulfurization on low nitrogen. On the front and back walls of the secondary air pipeMeanwhile, the plurality of limestone interfaces are arranged, the interfaces are staggered to effectively cover the width direction of the hearth, so that the limestone powder and the flue gas are fully mixed, and the limestone powder and the flue gas are used as flexible adjustment means for different working conditions during operation.
4. Adopts a low-nitrogen staged high-efficiency combustion technology: the furnace structure is optimized, the boiler air distribution adopts a three-level air supply mode, the air quantity ratio of an air distribution plate, a coal supply pipe and a secondary air pipe is selected according to the ratio of 4:1:5, the air of the air distribution plate is provided by a primary air blower, the air of the coal supply pipe is provided by mixing the sealing air of the coal supply machine of the primary air, the coal conveying air, the coal sowing air and the limestone conveying air of a limestone system, and the air of the secondary air pipe is provided by a secondary air blower. The technology realizes the synergy of NOx control and high-efficiency combustion by strengthening the bottom reducing atmosphere, grading supplementary air and middle-upper oxygen diffusion.
5. The technology of strong heat exchange tube bank for preventing dust accumulation is adopted: the average smoke speed of the tube bank is properly improved, ash deposition is prevented, heat exchange is enhanced, the tail fly ash has smaller particle size after the efficiency of the boiler separator is improved, the ash deposition phenomenon is formed by being more easily attached to the tube bank, and the heat exchange coefficient of the tube bank and the load carrying capacity of the boiler are weakened; by reasonably selecting the smoke discharging speed of the pipe, the disturbance of the smoke and the pipe is increased on the basis of not affecting the abrasion of the pipe, thereby preventing dust accumulation, enhancing heat exchange, reducing the smoke discharging temperature and improving the efficiency of the boiler.
6. The bottom and the top furnace walls of the steering room are obliquely arranged, and simultaneously, the corners are chamfered, so that corner abrasion and scouring can be effectively avoided, dust is accumulated at the bottom of the steering room, meanwhile, reasonable smoke guiding can effectively prevent the phenomenon that the smoke enters the tail part to generate bias flow, the contact between the smoke and the tail part heating surface is increased, the heat exchange effect is enhanced, and the smoke discharging temperature is further reduced.
7. The air flow rate (more than or equal to 85 m/s) of the secondary air nozzle is improved, the momentum of secondary air entering the hearth is increased, the disturbance and penetration capacity to the flue gas in the hearth are enhanced, the oxygen-deficient core is eliminated, the contact between air and the flue gas is fully realized, and the combustion efficiency and the desulfurization efficiency are improved. Meanwhile, the height (2.8-3.2 m) of the secondary air port from the air distribution plate is increased, the oxygen feeding is delayed, the lower reducing atmosphere is fully built, the generation of nitrogen oxides is inhibited, and the emission of the nitrogen oxides is controlled at 100mg/Nm 3 Hereinafter, the user only needs to divideThe SNCR denitration system is added at the inlet of the separator, so that the ultra-low emission (50 mg/Nm) of nitrogen oxides can be realized 3 The following are described below).
8. The SNCR denitration system spray guns are arranged in a staggered manner on the inner side and the outer side of the inlet of the separator, so that the height and depth directions of the denitration solution are uniformly distributed and enter the inlet flue of the separator, meanwhile, the length of the acceleration section for lengthening arrangement can fully realize the mixing of the denitration solution and the flue gas, the denitration efficiency is improved to more than 80%, and the running cost of a user can be greatly saved.
By applying the technology, the boiler is used as combustion heat exchange equipment and desulfurization and denitrification equipment, and only the dust remover is arranged at the tail part, so that the investment and operation of tail part environment-friendly equipment are greatly reduced. The performance indexes of high-efficiency desulfurization in the furnace, low initial NOx emission and high-efficiency combustion in the furnace are synchronously realized, and the method has high economic value and social benefit.
Drawings
Fig. 1 is a schematic view of the overall structure of the present invention.
Detailed Description
The first embodiment is as follows: referring to fig. 1, the embodiment is a low-level arrangement high-efficiency circulating fluidized bed boiler system for desulfurization and denitration in a furnace, which comprises a furnace 1, a separator 3, a top flue 4, a dust collector 7, a draught fan 8, a chimney 9, a water-cooling air chamber 10, a coal feeding pipe 12, a lower coal feeding pipe coal-air-blowing desulfurization pipeline 15, a coal feeding pipe coal-blowing pipeline 16, a tail flue 19, a plurality of secondary air pipes 11, a plurality of front side wall secondary air port desulfurization pipelines 13 and a plurality of rear side wall secondary air port desulfurization pipelines 14, wherein the air outlet end of the water-cooling air chamber 10 is connected with the lower inlet end of the furnace 1, the lower inlet end of the furnace 1 is provided with an air distribution plate 18, the outlet end of the coal feeding pipe 12 is connected with one side of the lower part of the furnace 1, the outlet end of the coal feeding pipe 12 is connected with the coal feeding pipe coal-blowing pipeline 16, one side of the coal feeding pipe coal-blowing pipeline 16 is connected with the lower coal feeding pipe coal-blowing desulfurization pipeline 15, the plurality of secondary air pipes 11 are uniformly distributed on the outer side of the hearth 1 along the circumferential direction, the outlet end of the secondary air pipes 11 is connected with the lower part of the hearth 1, the outlet end of the secondary air pipes 11 is arranged on the upper part of the outlet end of the coal feeding pipe 12, the outlet end of the secondary air pipes 11 arranged on the front side wall of the hearth 1 is connected with a front side wall secondary air port desulfurization pipeline 13, the outlet end of the secondary air pipes 11 arranged on the rear side wall of the hearth 1 is connected with a rear side wall secondary air port desulfurization pipeline 14, the upper outlet end of the hearth 1 is connected with the inlet end of the separator 3, the flue gas outlet end of the separator 3 is connected with the inlet end of the top flue 4, the outlet end of the top flue 4 is connected with the upper inlet end of the tail flue 19, the lower outlet end of the tail flue 19 is sequentially connected with the dust collector 7, the induced draft fan 8 and the chimney 9 from top to bottom, the powder outlet end of the separator 3 is connected with the lower part of the hearth 1 through a return leg 20.
The lower coal-feeding pipe is provided with a coal-air desulfurization pipeline 15 as a lime powder spraying interface and a calcium spraying interface.
The front side wall secondary air port desulfurization pipeline 13 and the rear side wall secondary air port desulfurization pipeline 14 are arranged in a staggered mode. The front side wall secondary air port desulfurization pipeline 13 and the rear side wall secondary air port desulfurization pipeline 14 are used as limestone interfaces.
The coal feeding port coal feeding air pipe is used as a thought of low-level arrangement of a lime powder spraying interface and a calcium spraying interface, and compared with a high-level arrangement structure of a secondary air pipe and a material returning leg, lime powder and coal can be mixed earlier in time and better in space, meanwhile, the flue gas pressure in the coal feeding pipe area is higher, the back pressure of limestone powder conveying air entering a boiler can be increased, the penetrating power of limestone conveying air is increased, a reasonable temperature field and an optimized oxygen field are designed, a new and improved in-furnace desulfurization reaction and combustion reaction double-coupling algorithm is applied, the heating surface structure and area arrangement are optimized, and SO can be realized when Ca/S is 1.5-2 2 The method can reach the ultra-low emission standard, can improve the boiler efficiency under the low Ca/S desulfurization working condition, and weaken the negative influence of desulfurization on low nitrogen. A plurality of limestone interfaces are simultaneously arranged on the front wall and the rear wall of the secondary air pipe in design, the interfaces are staggered to effectively cover the width direction of the hearth, so that the limestone powder and the flue gas are fully mixed, and the limestone powder and the flue gas are used as flexible adjustment means for different working conditions during operation.
The boiler is used as combustion heat exchange equipment and desulfurization and denitrification equipment, and only the dust remover is arranged at the tail part, so that the investment and operation of tail part environment-friendly equipment are greatly reduced. The performance indexes of high-efficiency desulfurization in the furnace, low initial NOx emission and high-efficiency combustion in the furnace are synchronously realized, and the method has high economic value and social benefit.
The second embodiment is as follows: the present embodiment will be described with reference to fig. 1, in which a tail heating surface 5 is provided in the middle of a tail flue 19. Other compositions and connection modes are the same as in the first embodiment.
And a third specific embodiment: the present embodiment will be described with reference to fig. 1, in which an air preheater 6 is provided at the lower portion of the back flue 19. Other compositions and connection modes are the same as those of the second embodiment.
The specific embodiment IV is as follows: referring to fig. 1, the separator 3 according to this embodiment includes a cylinder 3-1, a central cylinder 3-2, and an inlet flue 3-3, wherein an inlet end of the inlet flue 3-3 is connected to an upper outlet end of the furnace 1, an outlet end of the inlet flue 3-3 is connected to an upper inlet end of the cylinder 3-1, an inlet end of the central cylinder 3-2 is connected to a top flue gas outlet end of the cylinder 3-1, an outlet end of the central cylinder 3-2 is connected to an inlet end of the top flue 4, a lower powder outlet end of the cylinder 3-1 is connected to an upper inlet end of the return leg 20, and a lower outlet end of the return leg 20 is connected to a lower portion of the furnace 1. Other compositions and connection modes are the same as those of the first, second or third embodiments.
Fifth embodiment: in the present embodiment, the inlet flue 3-3 is of a fully declined and step-free structure, and the inlet flue 3-3 is disposed from the inlet end to the outlet end in a downward declined manner, as described in connection with fig. 1. Other compositions and connection modes are the same as those of the fourth embodiment.
The inlet flue of the separator adopts an innovative full declining structure, the declining angle is 9.5 degrees, the step at the joint of the declining section and the top of the separator cylinder body is cancelled, the higher flue gas inlet flow velocity (more than or equal to 30 m/s), the longer inlet accelerating section (more than or equal to 3 m) of the separator and the reasonable eccentric size of the central cylinder are selected, the flue gas flow field is optimized, the efficiency of the separator is further improved, superfine circulating ash particles d50 of 52.8 mu m are obtained, the circulating ash particle size is reduced, the reducing atmosphere of a dense-phase area is enhanced, the generation amount of NOx is reduced, and the residence time and the circulating times of fine particle fuel and limestone powder are increased, so that the combustion efficiency and the desulfurization efficiency are improved.
Specific embodiment six: the present embodiment is described with reference to fig. 1, in which an SNCR denitration system 17 is provided at the inlet end of the inlet flue 3-3. Other compositions and connection modes are the same as those of the fourth embodiment.
Seventh embodiment: referring to fig. 1, the SNCR denitration system 17 according to the present embodiment includes two groups of spray guns, and a group of spray guns are disposed on both inner and outer sides of an inlet end of the inlet flue 3-3, and each group of spray guns includes a plurality of spray guns disposed in a staggered manner. Other compositions and connection modes are the same as those of the sixth embodiment.
The SNCR denitration system spray guns are arranged in a staggered manner on the inner side and the outer side of the inlet of the separator, so that the height and depth directions of the denitration solution are uniformly distributed and enter the inlet flue of the separator, meanwhile, the length of the acceleration section for lengthening arrangement can fully realize the mixing of the denitration solution and the flue gas, the denitration efficiency is improved to more than 80%, and the running cost of a user can be greatly saved.
Eighth embodiment: the center lines of the center tube 3-2 and the tube body 3-1 according to the present embodiment are eccentrically disposed, as described with reference to fig. 1. Other compositions and connection modes are the same as those of the fourth embodiment.
Detailed description nine: the present embodiment will be described with reference to fig. 1, in which the top end surface of the furnace 1 is inclined downward from the outlet end side to the other side. Other compositions and connection modes are the same as in the first embodiment.
Detailed description ten: the present embodiment is described with reference to fig. 1, in which the top flue 4 is disposed obliquely downward from the inlet end to the outlet end. Other compositions and connection modes are the same as in the first embodiment.
The flue at the bottom and the flue at the top of the steering room are obliquely arranged, and simultaneously, the chamfer arrangement at each corner can effectively avoid corner abrasion and scouring, and the dust deposition at the bottom of the steering room can simultaneously reasonably guide the flue gas, so that the phenomenon that the flue gas flows into the tail part to generate bias flow can be effectively prevented, the contact between the flue gas and the heating surface of the tail part is increased, the heat exchange effect is enhanced, and the exhaust gas temperature is further reduced.
Principle of operation
The combustion method of the desulfurization and denitrification circulating fluidized bed boiler system in the low-level arrangement high-efficiency furnace comprises the following steps:
the method comprises the steps of measuring the minimum fluidization air quantity by performing a cold state test before the boiler is started, and maintaining the minimum fluidization air quantity to run in a subsequent furnace starting and coal feeding stage; at the moment, the boiler starts to normally run with load, coal-feeding wind and sealing wind of a coal feeding pipe and sealing wind of a coal feeding machine enter the hearth 1 through the coal feeding pipe 12 to participate in combustion, at the moment, the boiler is in an initial running stage, primary wind at the lower part of the air distribution plate 18 is used as main combustion wind to be matched with the coal-feeding wind for combustion, after the material returning system is established, the boiler is stable in running, a lower coal-feeding wind desulfurization pipeline 15 is started for feeding limestone into the hearth 1, and desulfurization in the furnace is started to ensure sulfur dioxide emission;
when the load of the boiler is raised to more than 30%, the secondary air pipe 11 can be opened to supplement combustion air into the hearth 1 (in order to ensure combustion efficiency and secondary air penetrating power, the secondary air flow cross section can be adjusted by adjusting the secondary air damper and the switch damper, so that the momentum of the secondary air entering the hearth is improved, the penetrating power is further enhanced, the effect of improving the combustion efficiency is achieved by disturbance is achieved, meanwhile, the primary air is required to be greater than the minimum fluidization air quantity, normal fluidization operation of the boiler is ensured, partial coking caused by poor fluidization is prevented, and the total oxygen content value of the tail part is required to be ensured to be 3-5% in the operation process. When the load of the boiler is required to be lifted according to the system, the boiler is required to be regulated stably according to the principle of adding coal and then adding air, the secondary air volume is increased mainly (the fluid cross section of the secondary air pipe is increased according to the condition of the secondary air volume, the combustion effect is ensured, the excessive resistance loss caused by the excessive secondary air flow rate is avoided at the same time), the primary air volume is gradually lifted according to the condition of the load and the air pressure of an air chamber (the primary air volume is regulated along with the load change in the operation process and is generally controlled to be 5.5-7.5 Kpa), and finally, the air distribution plate 18, the coal feeding pipe 12 and the secondary air pipe 11 are realized in the air volume proportion state according to the air volume ratio of 4:1:5 under the full load state, so that the optimal operation combustion and pollutant control state is achieved.
Meanwhile, the emission condition of nitrogen oxides and sulfur dioxide needs to be closely observed in the operation process of the boiler, and when the nitrogen oxides exceed the ultra-low emission limit value of 50mg/Nm 3 Starting the SNCR denitration system 17 to spray urea or ammonia water solution and nitrogen oxide for reduction reaction during limit valueThe nitrogen oxides can be strictly controlled below the emission requirement limit; unlike nitrogen oxides, sulfur dioxide removal needs to be put into use when the boiler operates, sulfur dioxide reaches an ultralow emission standard when Ca/S is 1.5-2 in cooperation with different operating states of the boiler, a high-efficiency separation system and a low-level arrangement idea, and the limestone consumption is reduced by strictly controlling in the operating process, so that the operating cost is reduced. If the lower coal-feeding pipe coal-air desulfurization pipeline 15 is blocked in the running process, the operation of the pipeline can be stopped and adjusted to be in-furnace desulfurization through the front and rear wall secondary air pipes, namely the front side wall secondary air port desulfurization pipeline 13 and the rear side wall secondary air port desulfurization pipeline 14, the ultra-low emission effect can be achieved, and after the blocked pipeline is dredged, the front side wall secondary air port desulfurization pipeline 13 and the rear side wall secondary air port desulfurization pipeline 14 can be converted and adjusted to be in a standby state.
The control principle and the adjustment mode are matched with the beneficial effects contained in the invention, so that the invention can be realized, namely, the low-level arranged high-efficiency in-furnace desulfurization and denitrification circulating fluidized bed boiler system is provided for solving the problem that the ultra-low emission and high energy efficiency of the existing circulating fluidized bed boiler are difficult to realize together.
Although the invention herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present invention. It is therefore to be understood that numerous modifications may be made to the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims. It should be understood that the different dependent claims and the features described herein may be combined in ways other than as described in the original claims. It is also to be understood that features described in connection with separate embodiments may be used in other described embodiments.

Claims (10)

1. A desulfurization and denitrification circulating fluidized bed boiler system in a low-level arrangement high-efficiency furnace is characterized in that: the device comprises a hearth (1), a separator (3), a top flue (4), a dust collector (7), an induced draft fan (8), a chimney (9), a water-cooling air chamber (10), a coal feeding pipe (12), a lower coal feeding pipe coal-air-blowing desulfurization pipeline (15), a coal feeding pipe coal-blowing pipeline (16), a tail flue (19), a plurality of secondary air pipes (11), a plurality of front side wall secondary air port desulfurization pipelines (13) and a plurality of rear side wall secondary air port desulfurization pipelines (14), wherein the air outlet end of the water-cooling air chamber (10) is connected with the inlet end of the lower part of the hearth (1), an air distribution plate (18) is arranged on the inlet end of the lower part of the hearth (1), the outlet end of the coal feeding pipe (12) is connected with one side of the lower part of the hearth (1), one side of the coal feeding pipe coal-blowing pipeline (16) is connected with the lower coal feeding pipe coal-blowing pipeline (15), the plurality of secondary air pipes (11) are uniformly distributed on the outer side of the hearth (1) along the circumferential direction, the outlet end of the secondary air pipes (11) is connected with the outlet end of the secondary air pipes (11) at the outlet end of the lower part of the hearth (1), the outlet end of a secondary air pipe (11) arranged on the rear side wall of the hearth (1) is connected with a rear side wall secondary air port desulfurization pipeline (14), the upper outlet end of the hearth (1) is connected with the inlet end of a separator (3), the flue gas outlet end of the separator (3) is connected with the inlet end of a top flue (4), the outlet end of the top flue (4) is connected with the upper inlet end of a tail flue (19), the lower outlet end of the tail flue (19) is sequentially connected with a dust collector (7), an induced draft fan (8) and a chimney (9) from front to back, and the powder outlet end of the separator (3) is connected with the lower part of the hearth (1) through a return leg (20).
2. The low-level arranged high-efficiency in-furnace desulfurization and denitrification circulating fluidized bed boiler system according to claim 1, wherein: the middle part of the tail flue (19) is provided with a tail heating surface (5).
3. The low-level arranged high-efficiency in-furnace desulfurization and denitrification circulating fluidized bed boiler system according to claim 2, wherein: the lower part of the tail flue (19) is provided with an air preheater (6).
4. A low-level arranged high-efficiency in-furnace desulfurization and denitrification circulating fluidized bed boiler system according to claim 1, 2 or 3, wherein: the separator (3) comprises a cylinder body (3-1), a central cylinder (3-2) and an inlet flue (3-3), wherein the inlet end of the inlet flue (3-3) is connected with the upper inlet end of the hearth (1), the outlet end of the inlet flue (3-3) is connected with the upper inlet end of the cylinder body (3-1), the inlet end of the central cylinder (3-2) is connected with the top flue gas outlet end of the cylinder body (3-1), the outlet end of the central cylinder (3-2) is connected with the inlet end of the top flue (4), the lower end powder outlet end of the cylinder body (3-1) is connected with the upper inlet end of a return leg (20), and the lower outlet end of the return leg (20) is connected with the lower part of the hearth (1).
5. The low-level arranged high-efficiency in-furnace desulfurization and denitrification circulating fluidized bed boiler system according to claim 4, wherein: the inlet flue (3-3) is of a full-declining step-free structure, and the inlet flue (3-3) is arranged in a downward inclined mode from the inlet end to the outlet end.
6. The low-level arranged high-efficiency in-furnace desulfurization and denitrification circulating fluidized bed boiler system according to claim 4, wherein: and an SNCR denitration system (17) is arranged at the inlet end of the inlet flue (3-3).
7. The low-level arranged high-efficiency in-furnace desulfurization and denitrification circulating fluidized bed boiler system according to claim 6, wherein: the SNCR denitration system (17) comprises two groups of spray guns, a group of spray guns are arranged on the inner side and the outer side of the inlet end of the inlet flue (3-3), and each group of spray guns comprises a plurality of spray guns which are arranged in a staggered mode.
8. The low-level arranged high-efficiency in-furnace desulfurization and denitrification circulating fluidized bed boiler system according to claim 4, wherein: the central lines of the central cylinder (3-2) and the cylinder body (3-1) are eccentrically arranged.
9. The low-level arranged high-efficiency in-furnace desulfurization and denitrification circulating fluidized bed boiler system according to claim 1, wherein: the top end surface of the hearth (1) is arranged in a downward inclined mode from the side of the outlet end to the other side of the outlet end.
10. The low-level arranged high-efficiency in-furnace desulfurization and denitrification circulating fluidized bed boiler system according to claim 1, wherein: the top flue (4) is arranged in a downward inclined mode from the inlet end to the outlet end.
CN202211689149.6A 2022-12-27 2022-12-27 Low-level arrangement high-efficiency boiler system with desulfurization and denitrification circulating fluidized bed in furnace Pending CN116146973A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116892722A (en) * 2023-07-10 2023-10-17 哈尔滨红光锅炉总厂有限责任公司 Pure coal powder circulating fluidized bed system

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116892722A (en) * 2023-07-10 2023-10-17 哈尔滨红光锅炉总厂有限责任公司 Pure coal powder circulating fluidized bed system
CN116892722B (en) * 2023-07-10 2024-05-10 哈尔滨红光锅炉总厂有限责任公司 Pure coal powder circulating fluidized bed system

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