CN110701606A - Boiler fly ash reburning device and method - Google Patents

Boiler fly ash reburning device and method Download PDF

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Publication number
CN110701606A
CN110701606A CN201911109626.5A CN201911109626A CN110701606A CN 110701606 A CN110701606 A CN 110701606A CN 201911109626 A CN201911109626 A CN 201911109626A CN 110701606 A CN110701606 A CN 110701606A
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China
Prior art keywords
ash
boiler
fly ash
communicated
material returning
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CN201911109626.5A
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Chinese (zh)
Inventor
赵树平
王建军
胡忠
张贞元
田晓飞
汪飞
郝广利
王继胜
周涛
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Shandong Fukuan Biological Engineering Co Ltd
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Shandong Fukuan Biological Engineering Co Ltd
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Priority to CN201911109626.5A priority Critical patent/CN110701606A/en
Publication of CN110701606A publication Critical patent/CN110701606A/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
    • 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
    • F23C10/24—Devices for removal of material from the bed
    • F23C10/26—Devices for removal of material from the bed combined with devices for partial reintroduction of material into the bed, e.g. after separation of agglomerated parts
    • 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 discloses a boiler fly ash reburning device, which relates to the technical field of boilers, wherein the upper end of a boiler is communicated with a cyclone separator, the cyclone separator is connected with an auxiliary heating surface of the boiler, the lower end of the auxiliary heating surface is communicated with an electrostatic dust collector, the electrostatic dust collector is communicated with a fly ash device, the fly ash device is connected with a material returning box, a material leg of the material returning box is connected with a boiler furnace, and a material returning device is connected with a material returning fan. The boiler fly ash collected by the electrostatic dust collector is returned to a charge leg of a material returning device of the boiler through the fly ash device and enters a hearth to be combusted along with the returned ash, so that the circulating ash amount in the hearth is increased, the bed temperature is reduced, the differential pressure of the hearth is improved, the outlet temperature of the hearth is also improved, the carbon content of the fly ash is reduced, and the application range of the boiler to coal is enlarged; the temperature reaction interval of the ammonia water is reached by controlling the ash return amount of the fly ash, so that the ammonia water and the nitrogen oxide in the flue gas are fully reacted, and the ammonia escape is reduced.

Description

Boiler fly ash reburning device and method
Technical Field
The invention relates to the technical field of boilers, in particular to a device and a method for reburning boiler fly ash.
Background
The design of the circulating fluidized bed boiler of the existing thermal power plant is generally a novel domestic boiler type with low bed temperature, low bed pressure and low nitrogen combustion, and the original discharge amount of nitrogen oxides is 70-160mg/m3The Nox emission standard executed 10 months before 2017 is less than or equal to 200mg/m3. In the period, the flue gas emission requirement can be met without adopting a SNCR ammonia water feeding denitration mode. After 10 months in 2017, environmental protection departments in many regions implement ultra-low emission standards, and the emission standard of Nox is less than or equal to 50mg/m3(ii) a In order to achieve standard emission, the boiler adopts an SNCR (selective non-catalytic reduction) denitration mode, and a denitration agent is generally ammonia water or urea. The consumption of designed ammonia water is generally 0.3-0.5 ton/h, and needs to be adjusted according to the original discharge amount of oxynitride of a boiler; the original discharge amount is different according to the temperature of the hearth and the outlet temperature of the hearth, and the reaction temperature is controlled to be between 850 ℃ and 930 ℃ in general. In order to ensure the sulfur dioxide to reach the standard, the sulfur content in the raw coal needs to be controlled at a lower level (below 0.8%). In actual operation, the using amount of the ammonia water reaches 0.5-0.8 ton/h, which is obviously larger than the design value, and the carbon content of the fly ash reaches more than 12% at most; for the situation, the research and analysis are earnestly carried out; there are two main reasons for agreement: firstly, the bed temperature of the boiler is higher, and reaches over 980 ℃ under high load, so that oxynitride is sharply increased at the temperature, and the used ammonia water is increased; secondly, the temperature of the outlet of the hearth is low, the load is difficult to be lifted, and the low differential pressure of the hearth is determined to be the main reason through careful analysis, and is closely related to the circulating ash of the boilerTherefore, it is urgent to increase the circulating ash amount while performing operation adjustment.
Disclosure of Invention
The invention aims to provide a boiler fly ash reburning device and a boiler fly ash reburning method, which are used for solving the problem of improving the circulating ash amount in the background technology.
In order to achieve the purpose, the invention provides the following technical scheme:
the boiler fly ash reburning device comprises a boiler, wherein the upper end of the boiler is communicated with a cyclone separator, the air outlet end of the cyclone separator is connected with an auxiliary heating surface of the boiler, the lower end of the auxiliary heating surface is communicated with an electrostatic dust collector, the ash outlet end of the electrostatic dust collector is communicated with a fly ash device, the fly ash device is connected with an ash storage room, the fly ash device is also connected with a material leg of a return box, the material leg of the return box is connected with a boiler hearth, and the lower end of a return feeder is connected with a return fan.
Further, the auxiliary heating surface comprises a superheater, an economizer and an air preheater, the superheater, the economizer and the air preheater are sequentially connected, the superheater is communicated with the cyclone separator, and the air preheater is communicated with the electrostatic dust collector.
Furthermore, the fly ash device comprises a powder pump, an ash conveying fan and an ash conveying pipeline, wherein an inlet of the powder pump is connected with an ash outlet end of the electrostatic dust collector, an outlet of the powder pump is communicated with the ash conveying pipeline, and the front end of the ash conveying pipeline is communicated with the ash conveying fan.
Furthermore, the ash conveying fan and the material returning fan are both Roots fans.
Furthermore, the material return box and the cyclone separator are both provided with two.
Further, the flying ash device is provided with two flying ash devices.
A method for reburning boiler fly ash comprises the following steps: boiler furnace export exhaust has the flue gas of tiny granule to get into cyclone, separate out the cigarette ash of great granule under the centrifugal force effect in cyclone, the cigarette ash of great granule of separating gets back to furnace through the effect of returning the material fan in getting into the returning charge ware and burns once more, and play the effect of control bed temperature, in addition return the returning charge ware of boiler through the fly ash device to the part tiny granule cigarette ash that electrostatic precipitator collected, get into furnace along with separating out the cigarette ash of great granule and participate in the burning together.
Further, the residual small particle soot collected by the electrostatic precipitator is fed to a soot storage room through another fly ash device for temporary storage.
Compared with the prior art, the invention has the beneficial effects that: the invention mainly returns the boiler fly ash collected by the electrostatic precipitator to the return feeder leg of the boiler through the fly ash device, and enters the hearth to burn along with the return ash, thus increasing the circulating ash amount in the hearth, reducing the bed temperature, improving the hearth differential pressure and improving the hearth outlet temperature, and the fly ash return ash amount is controlled to reach the temperature reaction interval (800-; and because the fly ash is re-combusted again, the carbon content of the fly ash is also reduced, and simultaneously, the load-lifting capacity of the boiler is greatly enhanced due to the improvement of the circulating ash content. Meanwhile, the ash content requirement of the purchased coal can be properly reduced, the calorific value of the purchased coal is improved, and the transportation and use cost is reduced. The coal ash which becomes solid waste is conveyed back to the boiler and enters the circulating fluidized system again, so that the ash content is increased, and the fly ash returning amount is controlled by adjusting the ash feeding amount of the feeder. The pneumatic ash conveying system sets the material level to ensure the supply amount of the returned fly ash.
Drawings
Fig. 1 is a schematic view of the overall structure of the present invention.
In the figure: 1 electrostatic precipitator, 2 superheater, 3 economizer, 4 air preheater, 5 boiler, 6 cyclone separator, 7 return box, 8 powder pump, 9 return fan and 10 ash conveying fan.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Example 1:
referring to fig. 1, the boiler fly ash reburning device comprises a boiler 5, wherein the upper end of the boiler 5 is communicated with a cyclone separator 7, the air outlet end of the cyclone separator 7 is connected with an auxiliary heating surface of the boiler 5, the lower end of the auxiliary heating surface is communicated with an electrostatic dust collector 1, the ash outlet end of the electrostatic dust collector 1 is communicated with a fly ash device, the fly ash device is connected with an ash storage room, the fly ash device is also connected with a material leg of a return box, the material leg of the return box is connected with a hearth of the boiler 5, and the lower end of the return device is connected with a return fan 9.
The auxiliary heating surface comprises a superheater 2, an economizer 3 and an air preheater 4, the superheater 2, the economizer 3 and the air preheater 4 are sequentially connected, the superheater 2 is communicated with a cyclone separator 7, and the air preheater 4 is communicated with an electrostatic dust collector 1. The auxiliary heating surface absorbs the radiant heat of the high-temperature flue gas in the flue. The flue gas is reliably cooled, and the dust removal effect of the electrostatic dust collector 1 can be better after the molten ash is condensed into ash powder balls.
The cyclone separator 7 is composed of a shell, a screen and an exhaust pipe, wherein the upper part of the shell is cylindrical, the lower part of the shell is in a hollow round table shape with a big top and a small bottom, a feeding air inlet pipe is arranged on one side of the top of the shell, a straight-through downward powder outlet pipe is arranged at the bottom of the shell, the upper part of the screen is cylindrical, the lower part of the screen is in a conical shape with a lower conical top, a discharge pipe with an inclination is arranged at the bottom of the screen and is arranged in the shell, and the exhaust pipe is.
The material returning box comprises a hearth, a material returning pipe, an expansion joint, an air box, a U-shaped valve material returning device, a water-cooling heat exchange pipe, a water inlet collecting box, a water outlet collecting box, a material returning vertical pipe and a high-temperature heat insulation cyclone separator 7, wherein the water-cooling heat exchange pipe is arranged between the U-shaped valve material returning device and the material returning vertical pipe, two ends of the water-cooling heat exchange pipe are respectively connected with the water inlet collecting box and the water outlet collecting box, the water inlet collecting box is communicated with a water inlet pipeline of the boiler 5, and the water outlet collecting box is communicated with a mixed collecting box of a. The material returning vertical pipe is connected with the lower end of the high-temperature heat-insulation cyclone separator 7, and the material returning vertical pipe and the high-temperature heat-insulation cyclone separator 7 form a blanking sealing loop. The lower end of the U-shaped valve material returning device is provided with an air box. Two ends of the material return pipe are respectively connected with the material return vertical pipe and the hearth, and an expansion joint is arranged on a vertical section of the material return pipe connected with the material return vertical pipe. The dust separated by the cyclone separator 7 enters the material returning vertical pipe, two ends of the water-cooling heat exchange pipe are connected with the water inlet header and the water outlet header, and the high-temperature material in the material returning vertical pipe is cooled by heat exchange in the water-cooling heat exchange pipe. And fluidized loosening air is fed from the air box, and the material level difference between the ascending section and the descending section of the U-shaped valve material returning device is used as the returning power of the circulating material, so that the circulating material is stably and orderly returned to the hearth, and the circulating combustion is realized. The high-temperature material separated from the high-temperature heat-insulation cyclone separator 7 is cooled to 150-200 ℃ by utilizing the heat exchange of the water-cooling heat exchange pipe, so that the U-shaped valve material returning device does not slag and coke when in operation, and hot water exchanged by the water-cooling heat exchanger is sent into a mixing header of a water supply pipeline through a water outlet header, so that the temperature of water in the mixing header is improved, the heat efficiency of the boiler 5 is improved, and the energy is saved.
Example 2:
referring to fig. 1, the boiler fly ash reburning device comprises a boiler 5, wherein the upper end of the boiler 5 is communicated with a cyclone separator 7, the air outlet end of the cyclone separator 7 is connected with an auxiliary heating surface of the boiler 5, the lower end of the auxiliary heating surface is communicated with an electrostatic dust collector 1, the ash outlet end of the electrostatic dust collector 1 is communicated with a fly ash device, the fly ash device is connected with an ash storage room, the fly ash device is also connected with a material leg of a return box, the material leg of the return box is connected with a hearth of the boiler 5, and the lower end of the return device is connected with a return fan 9.
The auxiliary heating surface comprises a superheater 2, an economizer 3 and an air preheater 4, the superheater 2, the economizer 3 and the air preheater 4 are sequentially connected, the superheater 2 is communicated with a cyclone separator 7, and the air preheater 4 is communicated with an electrostatic dust collector 1. The auxiliary heating surface absorbs the radiant heat of the high-temperature flue gas in the flue. The flue gas is reliably cooled, and the dust removal effect of the electrostatic dust collector 1 can be better after the molten ash is condensed into ash powder balls. The fly ash device comprises a powder pump 8, an ash conveying fan 10 and an ash conveying pipeline, wherein an inlet of the powder pump 8 is connected with an ash outlet end of the electrostatic dust collector 1, an outlet of the powder pump 8 is communicated with the ash conveying pipeline, and the front end of the ash conveying pipeline is communicated with the ash conveying fan 10.
The cyclone separator 7 is composed of a shell, a screen and an exhaust pipe, wherein the upper part of the shell is cylindrical, the lower part of the shell is in a hollow round table shape with a big top and a small bottom, a feeding air inlet pipe is arranged on one side of the top of the shell, a straight-through downward powder outlet pipe is arranged at the bottom of the shell, the upper part of the screen is cylindrical, the lower part of the screen is in a conical shape with a lower conical top, a discharge pipe with an inclination is arranged at the bottom of the screen and is arranged in the shell, and the exhaust pipe is.
The material returning box comprises a hearth, a material returning pipe, an expansion joint, an air box, a U-shaped valve material returning device, a water-cooling heat exchange pipe, a water inlet collecting box, a water outlet collecting box, a material returning vertical pipe and a high-temperature heat insulation cyclone separator 7, wherein the water-cooling heat exchange pipe is arranged between the U-shaped valve material returning device and the material returning vertical pipe, two ends of the water-cooling heat exchange pipe are respectively connected with the water inlet collecting box and the water outlet collecting box, the water inlet collecting box is communicated with a water inlet pipeline of the boiler 5, and the water outlet collecting box is communicated with a mixed collecting box of a. The material returning vertical pipe is connected with the lower end of the high-temperature heat-insulation cyclone separator 7, and the material returning vertical pipe and the high-temperature heat-insulation cyclone separator 7 form a blanking sealing loop. The lower end of the U-shaped valve material returning device is provided with an air box. Two ends of the material return pipe are respectively connected with the material return vertical pipe and the hearth, and an expansion joint is arranged on a vertical section of the material return pipe connected with the material return vertical pipe. The dust separated by the cyclone separator 7 enters the material returning vertical pipe, two ends of the water-cooling heat exchange pipe are connected with the water inlet header and the water outlet header, and the high-temperature material in the material returning vertical pipe is cooled by heat exchange in the water-cooling heat exchange pipe. And fluidized loosening air is fed from the air box, and the material level difference between the ascending section and the descending section of the U-shaped valve material returning device is used as the returning power of the circulating material, so that the circulating material is stably and orderly returned to the hearth, and the circulating combustion is realized. The high-temperature material separated from the high-temperature heat-insulation cyclone separator 7 is cooled to 150-200 ℃ by utilizing the heat exchange of the water-cooling heat exchange pipe, so that the U-shaped valve material returning device does not slag and coke when in operation, and hot water exchanged by the water-cooling heat exchanger is sent into a mixing header of a water supply pipeline through a water outlet header, so that the temperature of water in the mixing header is improved, the heat efficiency of the boiler 5 is improved, and the energy is saved.
Example 3:
referring to fig. 1, the boiler fly ash reburning device comprises a boiler 5, wherein the upper end of the boiler 5 is communicated with a cyclone separator 7, the air outlet end of the cyclone separator 7 is connected with an auxiliary heating surface of the boiler 5, the lower end of the auxiliary heating surface is communicated with an electrostatic dust collector 1, the ash outlet end of the electrostatic dust collector 1 is communicated with a fly ash device, the fly ash device is connected with an ash storage room, the fly ash device is also connected with a material leg of a return box, the material leg of the return box is connected with a hearth of the boiler 5, and the lower end of the return device is connected with a return fan 9.
The auxiliary heating surface comprises a superheater 2, an economizer 3 and an air preheater 4, the superheater 2, the economizer 3 and the air preheater 4 are sequentially connected, the superheater 2 is communicated with a cyclone separator 7, and the air preheater 4 is communicated with an electrostatic dust collector 1. The auxiliary heating surface absorbs the radiant heat of the high-temperature flue gas in the flue. The flue gas is reliably cooled, and the dust removal effect of the electrostatic dust collector 1 can be better after the molten ash is condensed into ash powder balls. The fly ash device comprises a powder pump 8, an ash conveying fan 10 and an ash conveying pipeline, wherein an inlet of the powder pump 8 is connected with an ash outlet end of the electrostatic dust collector 1, an outlet of the powder pump 8 is communicated with the ash conveying pipeline, and the front end of the ash conveying pipeline is communicated with the ash conveying fan 10. The ash conveying fan 10 and the material returning fan 9 are both Roots fans. The two return boxes 8 and the two cyclone separators 7 are arranged. The flying ash device is provided with two.
The cyclone separator 7 is composed of a shell, a screen and an exhaust pipe, wherein the upper part of the shell is cylindrical, the lower part of the shell is in a hollow round table shape with a big top and a small bottom, a feeding air inlet pipe is arranged on one side of the top of the shell, a straight-through downward powder outlet pipe is arranged at the bottom of the shell, the upper part of the screen is cylindrical, the lower part of the screen is in a conical shape with a lower conical top, a discharge pipe with an inclination is arranged at the bottom of the screen and is arranged in the shell, and the exhaust pipe is.
The material returning box comprises a hearth, a material returning pipe, an expansion joint, an air box, a U-shaped valve material returning device, a water-cooling heat exchange pipe, a water inlet collecting box, a water outlet collecting box, a material returning vertical pipe and a high-temperature heat insulation cyclone separator 7, wherein the water-cooling heat exchange pipe is arranged between the U-shaped valve material returning device and the material returning vertical pipe, two ends of the water-cooling heat exchange pipe are respectively connected with the water inlet collecting box and the water outlet collecting box, the water inlet collecting box is communicated with a water inlet pipeline of the boiler 5, and the water outlet collecting box is communicated with a mixed collecting box of a. The material returning vertical pipe is connected with the lower end of the high-temperature heat-insulation cyclone separator 7, and the material returning vertical pipe and the high-temperature heat-insulation cyclone separator 7 form a blanking sealing loop. The lower end of the U-shaped valve material returning device is provided with an air box. Two ends of the material return pipe are respectively connected with the material return vertical pipe and the hearth, and an expansion joint is arranged on a vertical section of the material return pipe connected with the material return vertical pipe. The dust separated by the cyclone separator 7 enters the material returning vertical pipe, two ends of the water-cooling heat exchange pipe are connected with the water inlet header and the water outlet header, and the high-temperature material in the material returning vertical pipe is cooled by heat exchange in the water-cooling heat exchange pipe. And fluidized loosening air is fed from the air box, and the material level difference between the ascending section and the descending section of the U-shaped valve material returning device is used as the returning power of the circulating material, so that the circulating material is stably and orderly returned to the hearth, and the circulating combustion is realized. The high-temperature material separated from the high-temperature heat-insulation cyclone separator 7 is cooled to 150-200 ℃ by utilizing the heat exchange of the water-cooling heat exchange pipe, so that the U-shaped valve material returning device does not slag and coke when in operation, and hot water exchanged by the water-cooling heat exchanger is sent into a mixing header of a water supply pipeline through a water outlet header, so that the temperature of water in the mixing header is improved, the heat efficiency of the boiler 5 is improved, and the energy is saved.
Example 4:
referring to fig. 1, the boiler fly ash reburning device comprises a boiler 5, wherein the upper end of the boiler 5 is communicated with a cyclone separator 7, the air outlet end of the cyclone separator 7 is connected with an auxiliary heating surface of the boiler 5, the lower end of the auxiliary heating surface is communicated with an electrostatic dust collector 1, the ash outlet end of the electrostatic dust collector 1 is communicated with a fly ash device, the fly ash device is connected with an ash storage room, the fly ash device is also connected with a material leg of a return box, the material leg of the return box is connected with a hearth of the boiler 5, and the lower end of the return device is connected with a return fan 9.
The auxiliary heating surface comprises a superheater 2, an economizer 3 and an air preheater 4, the superheater 2, the economizer 3 and the air preheater 4 are sequentially connected, the superheater 2 is communicated with a cyclone separator 7, and the air preheater 4 is communicated with an electrostatic dust collector 1. The auxiliary heating surface absorbs the radiant heat of the high-temperature flue gas in the flue. The flue gas is reliably cooled, and the dust removal effect of the electrostatic dust collector 1 can be better after the molten ash is condensed into ash powder balls. The fly ash device comprises a powder pump 8, an ash conveying fan 10 and an ash conveying pipeline, wherein an inlet of the powder pump 8 is connected with an ash outlet end of the electrostatic dust collector 1, an outlet of the powder pump 8 is communicated with the ash conveying pipeline, and the front end of the ash conveying pipeline is communicated with the ash conveying fan 10. The fly ash device adopts pneumatic transmission, namely a method for conveying granular solid materials in a pipeline by using gas flow as transmission power. The flow conditions of the material in the pipeline are complex in practice and vary significantly mainly with the speed of the gas flow, the amount of material contained in the gas flow, the material properties of the material, etc. The solid content is lower than 1-10kg/m3, the operation gas velocity is higher (about 18-30 m/s), and the conveying distance is basically within 300 m. For the material seal pump of the prior mature equipment, the conveying operation is simple, no mechanical rotating part is needed, the conveying pressure is low, and no maintenance and maintenance are needed! The low-pressure system (dilute phase system) is divided into positive pressure and negative pressure, the system has high conveying speed and low material-gas ratio, the rotary valve is generally adopted for blanking, the air blower is used for providing the combination of air sources, the initial speed is generally 12M/S, the tail end speed is 25M/S, the conveying pressure is generally about 0.1MPA, and the tail end pressure is close to zero. The invention adopts a low-pressure positive-pressure system (dilute-phase system), and the low end pressure of the system can not influence the circulating system of the boiler 5. The ash conveying fan 10 and the material returning fan 9 are both Roots fans. The two return boxes 8 and the two cyclone separators 7 are arranged. The flying ash device is provided with two.
The cyclone separator 7 is composed of a shell, a screen and an exhaust pipe, wherein the upper part of the shell is cylindrical, the lower part of the shell is in a hollow round table shape with a big top and a small bottom, a feeding air inlet pipe is arranged on one side of the top of the shell, a straight-through downward powder outlet pipe is arranged at the bottom of the shell, the upper part of the screen is cylindrical, the lower part of the screen is in a conical shape with a lower conical top, a discharge pipe with an inclination is arranged at the bottom of the screen and is arranged in the shell, and the exhaust pipe is.
The material returning box comprises a hearth, a material returning pipe, an expansion joint, an air box, a U-shaped valve material returning device, a water-cooling heat exchange pipe, a water inlet collecting box, a water outlet collecting box, a material returning vertical pipe and a high-temperature heat insulation cyclone separator 7, wherein the water-cooling heat exchange pipe is arranged between the U-shaped valve material returning device and the material returning vertical pipe, two ends of the water-cooling heat exchange pipe are respectively connected with the water inlet collecting box and the water outlet collecting box, the water inlet collecting box is communicated with a water inlet pipeline of the boiler 5, and the water outlet collecting box is communicated with a mixed collecting box of a. The material returning vertical pipe is connected with the lower end of the high-temperature heat-insulation cyclone separator 7, and the material returning vertical pipe and the high-temperature heat-insulation cyclone separator 7 form a blanking sealing loop. The lower end of the U-shaped valve material returning device is provided with an air box. Two ends of the material return pipe are respectively connected with the material return vertical pipe and the hearth, and an expansion joint is arranged on a vertical section of the material return pipe connected with the material return vertical pipe. The dust separated by the cyclone separator 7 enters the material returning vertical pipe, two ends of the water-cooling heat exchange pipe are connected with the water inlet header and the water outlet header, and the high-temperature material in the material returning vertical pipe is cooled by heat exchange in the water-cooling heat exchange pipe. And fluidized loosening air is fed from the air box, and the material level difference between the ascending section and the descending section of the U-shaped valve material returning device is used as the returning power of the circulating material, so that the circulating material is stably and orderly returned to the hearth, and the circulating combustion is realized. The high-temperature material separated from the high-temperature heat-insulation cyclone separator 7 is cooled to 150-200 ℃ by utilizing the heat exchange of the water-cooling heat exchange pipe, so that the U-shaped valve material returning device does not slag and coke when in operation, and hot water exchanged by the water-cooling heat exchanger is sent into a mixing header of a water supply pipeline through a water outlet header, so that the temperature of water in the mixing header is improved, the heat efficiency of the boiler 5 is improved, and the energy is saved.
A method for reburning boiler fly ash comprises the following steps: 5 furnace exit exhaust of boiler has flue gas of small granule to get into cyclone 7, separate out the cigarette ash of great granule under the centrifugal force effect in cyclone 7, the cigarette ash of great granule of separating gets back to furnace through the effect of returning to material fan 9 in getting into the returning charge ware and burns again, and play the effect of control bed temperature, in addition, the partly small granule cigarette ash that collects electrostatic precipitator 1 passes through the flying dust device and returns back to the returning charge ware of boiler 5, get into furnace along with separating out the cigarette ash of great granule and participate in the burning together. In addition, the remaining small particle soot collected by the electrostatic precipitator 1 is temporarily stored in a storage compartment by another fly ash device.
It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.

Claims (8)

1. A boiler fly ash reburning device is characterized in that: the device comprises a boiler (5), wherein the upper end of the boiler (5) is communicated with a cyclone separator (7), the air outlet end of the cyclone separator (7) is connected with an auxiliary heating surface of the boiler (5), the lower end of the auxiliary heating surface is communicated with an electrostatic dust collector (1), the ash outlet end of the electrostatic dust collector (1) is communicated with a fly ash device, the fly ash device is connected with an ash storage room, the fly ash device is also connected with a dipleg of a return box, the dipleg of the return box is connected with a hearth of the boiler (5), and the lower end of a return feeder is connected with a return fan (9).
2. The boiler fly ash afterburning apparatus of claim 1, wherein: the auxiliary heating surface comprises a superheater (2), an economizer (3) and an air preheater (4), the superheater (2), the economizer (3) and the air preheater (4) are sequentially connected, the superheater (2) is communicated with a cyclone separator (7), and the air preheater (4) is communicated with the electrostatic dust collector (1).
3. The boiler fly ash afterburning apparatus of claim 1, wherein: the fly ash device comprises a powder pump (8), an ash conveying fan (10) and an ash conveying pipeline, wherein an inlet of the powder pump (8) is connected with an ash outlet end of the electrostatic dust collector (1), an outlet of the powder pump (8) is communicated with the ash conveying pipeline, and the front end of the ash conveying pipeline is communicated with the ash conveying fan (10).
4. The boiler fly ash afterburning apparatus of claim 1, wherein: the ash conveying fan (10) and the material returning fan (9) are both Roots fans.
5. The boiler fly ash afterburning apparatus of claim 1, wherein: the two return boxes (8) and the two cyclone separators (7) are arranged.
6. The boiler fly ash afterburning apparatus of claim 1, wherein: the flying ash device is provided with two.
7. A method for reburning boiler fly ash is characterized in that: the method for reburning the boiler fly ash comprises the following steps: boiler (5) furnace export exhaust have the flue gas of granule to get into cyclone (7), separate out the cigarette ash of great granule under centrifugal force in cyclone (7), the cigarette ash of great granule of separating gets into to get back to furnace through the effect of returning to material fan (9) in the returning charge ware and burns again, and play the effect of control bed temperature, in addition, the partial granule cigarette ash that collects electrostatic precipitator (1) passes through the flying dust device and returns back to the returning charge ware of boiler (5), get into furnace along with separating out the cigarette ash of great granule and participate in the burning together.
8. The boiler fly ash afterburning method of claim 7, wherein: the residual small-particle soot collected by the electrostatic precipitator (1) enters a soot storage room through another fly ash device for temporary storage.
CN201911109626.5A 2019-11-14 2019-11-14 Boiler fly ash reburning device and method Withdrawn CN110701606A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110701607A (en) * 2019-11-14 2020-01-17 山东福宽生物工程有限公司 Boiler fly ash reburning device and method

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110701607A (en) * 2019-11-14 2020-01-17 山东福宽生物工程有限公司 Boiler fly ash reburning device and method

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