CN114225682B - Low-load denitration method for circulating fluidized bed boiler - Google Patents

Low-load denitration method for circulating fluidized bed boiler Download PDF

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CN114225682B
CN114225682B CN202111269071.8A CN202111269071A CN114225682B CN 114225682 B CN114225682 B CN 114225682B CN 202111269071 A CN202111269071 A CN 202111269071A CN 114225682 B CN114225682 B CN 114225682B
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reducing agent
cooling liquid
annular disk
denitration
integrated system
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CN114225682A (en
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杨立旋
张茂珍
辛智刚
仝志鹏
郝海军
李锦乾
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Shanxi Yuguang Power Generation Co ltd
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Shanxi Yuguang Power Generation Co ltd
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/346—Controlling the process
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/46—Removing components of defined structure
    • B01D53/54—Nitrogen compounds
    • B01D53/56—Nitrogen oxides
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
    • B01D53/77—Liquid phase processes
    • B01D53/79—Injecting reactants
    • 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
    • F23J15/022—Arrangements of devices for treating smoke or fumes of purifiers, e.g. for removing noxious material for removing solid particulate material from the gasflow
    • 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
    • F23J15/022—Arrangements of devices for treating smoke or fumes of purifiers, e.g. for removing noxious material for removing solid particulate material from the gasflow
    • F23J15/025—Arrangements of devices for treating smoke or fumes of purifiers, e.g. for removing noxious material for removing solid particulate material from the gasflow using filters
    • 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
    • F23J15/04—Arrangements of devices for treating smoke or fumes of purifiers, e.g. for removing noxious material using washing fluids
    • 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
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2251/00—Reactants
    • B01D2251/20—Reductants
    • B01D2251/206—Ammonium compounds
    • B01D2251/2062—Ammonia
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2251/00—Reactants
    • B01D2251/20—Reductants
    • B01D2251/206—Ammonium compounds
    • B01D2251/2067—Urea
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2258/00—Sources of waste gases
    • B01D2258/02—Other waste gases
    • B01D2258/0283—Flue gases
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES 
    • F23J2215/00—Preventing emissions
    • F23J2215/10—Nitrogen; Compounds thereof
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES 
    • F23J2219/00—Treatment devices
    • F23J2219/20—Non-catalytic reduction devices

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Environmental & Geological Engineering (AREA)
  • General Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Biomedical Technology (AREA)
  • Health & Medical Sciences (AREA)
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  • Oil, Petroleum & Natural Gas (AREA)
  • Treating Waste Gases (AREA)
  • Chimneys And Flues (AREA)

Abstract

The invention discloses a low-load denitration system and a low-load denitration method for a circulating fluidized bed boiler, the low-load denitration system comprises the boiler and a denitration integrated system, wherein a movable rod piece is arranged at the top of the boiler, a fixed rod is arranged outside the denitration integrated system, the fixed rod is distributed left and right symmetrically, the denitration integrated system comprises a denitration integrated system shell, a second shell, a third shell, a reducing agent pipeline, a high-temperature cooling liquid conveying pipeline, a reducing agent spray gun, a first annular disk temperature measuring element and a second annular disk temperature measuring element, a lifting system is arranged at the outer top of the boiler, a reducing agent liquid storage tank, a cooling liquid storage tank and a fly ash ammonia concentration online detection system are arranged outside the boiler, and the liquid storage tank is connected with the denitration integrated system through a flexible material section reducing agent conveying pipe, a flexible material section cooling liquid conveying pipe and a flexible material section high-temperature cooling liquid conveying pipe respectively. The invention is suitable for low-load denitration of the circulating fluidized bed boiler.

Description

Low-load denitration method for circulating fluidized bed boiler
Technical Field
The invention relates to the field of denitration in low-load operation of a circulating fluidized bed boiler, in particular to a low-load denitration method and an online fly ash ammonia concentration detection method for the circulating fluidized bed boiler.
Background
Along with the proposal of a double-carbon target and strategy, the traditional thermal power deep peak shaving is gradually normalized, the thermal power generation mainly of the circulating fluidized bed boiler in part of areas is gradually changed into the supplementary standby row and column in a specific period, the circulating fluidized bed boiler is also gradually adjusted from full load adjustment to low load operation, the denitration reaction and the temperature area of an SNCR denitration system matched with the circulating fluidized bed boiler are difficult to match, the denitration efficiency is reduced, and the improvement and the upgrading of the SNCR system in stock are urgently required by innovative technology.
The SNCR denitration technology is fully called as a selective non-catalytic reduction denitration technology, and atomized reducing agent is sprayed into the flue gas at a proper temperature under the action of no catalyst to reduce nitrogen oxides in the flue gas into nitrogen and water. Ammonia, urea and hydro-ammonia are common reducing agents, with urea being widely used for safety and price advantages. Although SNCR denitration technology does not use a catalyst, the reaction condition is a high-temperature environment, and the temperature range of the reaction is generally 850-1100 ℃.
The temperature of the horizontal flue position of the circulating fluidized bed boiler can meet the temperature condition required by the technology under normal load and full load operation conditions, so that the traditional denitration position is positioned at the horizontal flue. And the temperature of the horizontal flue is lower than the temperature required by the reaction when the boiler operates under the low-load condition, so how to ensure the reaction temperature is the key for realizing flexible switching between high and low loads of the circulating fluidized bed boiler. The prior boiler reconstruction mainly comprises the steps of injecting a spray gun into a hearth through the wall surface of the boiler to react with flue gas, wherein the spray gun has the following defects: firstly, because the temperature fluctuation in the hearth is larger and the position of the spray gun is relatively fixed, the temperature influence is larger; secondly, the rising speed of the air flow in the central area of the hearth is higher, and the atomized reducing agent is blown to the wall surface and cannot reach the central area with higher temperature, so that the denitration efficiency is lower.
Disclosure of Invention
The invention provides a low-load denitration method for a circulating fluidized bed boiler, which is favorable for solving the problems of the SNCR low-load denitration method of the traditional circulating fluidized bed boiler, solves the problem that the position fixation of a spray gun is difficult to adapt to large-amplitude temperature fluctuation in a hearth, and is favorable for matching a proper temperature zone without denitration reaction under a low-load condition; the invention solves the problem that the atomized reducing agent is blown to the wall surface and cannot reach the central area with higher temperature, and is beneficial to the intensive mixing of the reducing agent in the central area; the invention provides a detection system for amine in ash, which is favorable for accurately obtaining amine escape information, can further improve the accuracy of controlling the injection quantity of a reducing agent and reduces the negative influence caused by excessive injection of the reducing agent.
In order to solve the technical problems, the embodiment of the invention provides the following scheme:
the utility model provides a be used for circulating fluidized bed boiler low-load denitration method, includes boiler and denitration integrated system, movable member is equipped with at the top of boiler, denitration integrated system's externally mounted has the dead lever, and dead lever bilateral symmetry distributes, denitration integrated system includes denitration integrated system shell, second shell, third shell, reductant pipeline, high temperature coolant delivery pipeline, reductant spray gun, first ring dish temperature measurement component and second ring dish temperature measurement component, the outside top of boiler is installed operating system, and is provided with reductant liquid storage pot, coolant liquid storage pot, fly ash ammonia concentration on-line measuring system outward, the liquid storage pot links to each other with denitration integrated system through flexible material section reductant conveyer pipe, flexible material section coolant liquid conveyer pipe, flexible material section high temperature coolant liquid conveyer pipe respectively, the dead lever is connected with movable dead lever from top to bottom, and can reciprocate the dead lever and be adjusted by operating system control.
Preferably, a cavity is formed among the denitration integrated system shell, the second shell, the third shell, the reducing agent pipeline, the high-temperature cooling liquid conveying pipe and the reducing agent spray gun, and cooling liquid is filled in the cavity.
Preferably, the reducing agent delivery pipe is used for delivering the reducing agent to the reducing agent spray gun, the reducing agent is sprayed into the hearth after being atomized, the cooling liquid is arranged around the reducing agent delivery pipe and the reducing agent spray gun, and the cooling liquid after absorbing heat is pumped out of the denitration integrated system through the high-temperature cooling liquid delivery pipeline.
Preferably, the shell denitration integrated system shell and the second shell form a first annular disk, the second shell and the third shell form a second annular disk, and the first annular disk temperature measuring element and the second annular disk temperature measuring element are arranged on the first annular disk and at the bottom center of the second annular disk, so that the environmental temperature where the reaction is located is monitored in real time.
Preferably, a cooling liquid delivery pump is connected to the inner wall of one side of the cooling liquid storage tank, cooling liquid is pumped out of the cooling liquid storage tank by the cooling liquid delivery pump, the cooling liquid is sequentially delivered into the denitration integrated system through a cooling liquid flowmeter, a cooling liquid regulating valve and a flexible material section cooling liquid delivery pipe, and the cooling liquid after heat absorption is delivered into the cooling liquid storage tank for recirculation after being cooled in the cooling liquid cooling system through a flexible material section high-temperature cooling liquid delivery pipe and a high-temperature cooling liquid outlet regulating valve under the action of a water suction pump; the reducing agent is pumped out of the reducing agent storage tank by the infusion pump and sequentially conveyed into the denitration integrated system through the reducing agent flowmeter, the first reducing agent regulating valve and the flexible material section reducing agent conveying pipe.
Preferably, the cross section of the annular disk of the first annular disk is divided into two types of rectangle and square, reducing agent spray guns are embedded in the annular disk, the reducing agent spray guns are symmetrically distributed, all spray guns in the first annular disk are connected to the same infusion tube, and the infusion tube in the annular disk is connected with a reducing agent infusion pipeline of the denitration integrated system; the spray gun outlet in the annular disk faces the wall surface of the hearth, the normal line of the spray gun outlet surface forms a certain included angle with the horizontal plane, and the normal line and the wall surface intersect at a point which is lower than the horizontal plane of the center of the annular disk.
Preferably, the cross section of the ring disc of the second ring disc is circular, a plurality of spray guns are symmetrically distributed in the ring disc, all spray guns in the ring disc are connected to the same infusion tube, and the infusion tube in the ring disc is connected with a reducing agent infusion pipeline of the denitration integrated system; the spray gun outlet in the annular disk faces the circle center, a certain included angle is formed between the normal line of the spray gun outlet surface and the horizontal plane, and the normal line and the central axis of the denitration integrated system are converged at one point and are lower than the horizontal plane of the center of the annular disk.
Preferably, the second shell and the third shell respectively form a convex part, the projection on the horizontal plane covers the upper edge part of the reducing agent spray gun, the first annular disk temperature measuring element and the second annular disk temperature measuring element main body are immersed in the cooling liquid, the temperature measuring probe penetrates through the wall surface of the metal pipe fitting to penetrate into the hearth, and the first annular disk temperature measuring element and the second annular disk temperature measuring element main body are connected with the external display screen of the boiler and the control system through wires.
Preferably, the online detection system for ammonia concentration of the fly ash comprises compressed air, a fly ash feed inlet, a fly ash heating kettle, a first electric heating wire, a second electric heating wire, a fly ash filter screen, a high-temperature resistant guide pipe, a push rod, a spring and a spherical valve, wherein the spherical valve is positioned at the bottom of the fly ash heating kettle, the fly ash feed inlet is positioned at the top of the fly ash heating kettle, an inlet of the compressed air is positioned on the side edge of the upper part of the fly ash heating kettle, the filter screen is positioned between the fly ash heating kettle and the high-temperature resistant guide pipe, the fly ash heating kettle is surrounded by the first electric heating wire, the high-temperature resistant guide pipe is surrounded by the second electric heating wire, the push rod drives the spherical valve to be in tight contact with the bottom of the fly ash heating kettle under the action of the spring to form a sealing environment, and one end of the high-temperature resistant guide pipe is connected with a gas ammonia concentration tester.
Preferably, the lifting system comprises a first bearing frame, a second bearing frame, a third bearing frame, a fourth fixed pin, a second fixed pin, a third fixed pin, a first fixed pin, a connecting rod, a winch, a first cable and a second cable, wherein the first cable on the winch is sequentially wound around a second fixed pulley and a third pulley and is connected with the second fixed pin; the second mooring ropes are divided into two groups, the two groups are symmetrically distributed, one end of each second mooring rope is connected with a third fixed pin, and the other end of each second mooring rope is connected with the first fixed pin around fixed pulleys on two sides of the second bearing frame; the connecting rod is connected with the first bearing frame; and each bearing frame is provided with a second fixing pin.
The scheme of the invention at least comprises the following beneficial effects:
according to the scheme, the proper temperature of the denitration reaction is ensured as much as possible, namely, the fixing rod capable of moving up and down is arranged at the top of the hearth and stretches into the dilute phase region, the denitration integrated system with the reducing agent spray gun is fixedly connected with the fixing rod, and the height of the denitration integrated system is adjusted within a certain range according to the display temperature of the temperature measuring element; meanwhile, the denitration system is divided into a flexible material section and a rigid material section, and the flexibility of up-and-down movement of the denitration integrated system is achieved through segmentation;
the contact area of the reducing agent and the flue gas is increased by arranging a plurality of spray guns in the annular disc. Meanwhile, the denitration efficiency is improved to the maximum extent by changing the direction of the nozzle, fully utilizing the characteristic of high central temperature of the hearth, and cooling the reducing agent conveying pipe and the spray gun in the hearth through circulation of cooling liquid, so that the reducing agent is prevented from being decomposed too early due to high temperature, and the reducing agent utilization rate is effectively improved;
the high-temperature cooling liquid is pumped out by the infusion tube directly reaching the bottom of the denitration integrated system, the cooling liquid is accelerated to circulate, the system is effectively cooled, solid particles are collected on line, the ammonia content in fly ash is measured in real time by utilizing the characteristics of decomposing ammonia salt at high temperature and escaping ammonia, the feeding amount of the reducing agent is effectively fed back and adjusted, the effective utilization rate of the reducing agent is improved, and the lifting system uses the telescopic arm stroke amplification principle to control the lifting mechanism to have smaller volume on the premise of reaching the required height.
Drawings
Fig. 1 is a schematic connection diagram of a denitration integrated system provided by the invention.
Fig. 2 is a schematic diagram of the structure of the injector of the denitration system provided by the invention.
Fig. 3 is a top view of a first ring disc corresponding to a first structure according to an embodiment of the present invention.
Fig. 4 is a top view of a first ring disc corresponding to a second structure according to an embodiment of the present invention.
Fig. 5 is a top view of a second ring disk corresponding structure according to an embodiment of the present invention.
FIG. 6 is a schematic diagram of an online detection system for ammonia concentration in fly ash according to an embodiment of the invention.
Fig. 7 is a schematic structural diagram of lifting equipment of a denitration integrated system according to an embodiment of the present invention.
Fig. 8 is a flowchart of feedback adjustment control according to an embodiment of the present invention.
Reference numerals:
A. a denitration injection system; B. a lifting system; 1. a boiler; 2. a reducing agent storage tank; 3. a reducing agent delivery pump; 4. a reductant flow meter; 5. a first reducing agent regulating valve; 6. a flexible material segment reductant delivery tube; 7. a cooling liquid storage tank; 8. a cooling liquid delivery pump; 9. a coolant flow meter; 10. a coolant regulating valve; 11. a flexible material section coolant delivery tube; 12. a flexible material section high temperature coolant delivery tube; 13. a water pump; 14. a high temperature coolant outlet regulator valve; 15. a cooling liquid cooling system; 16. a movable rod; 17. denitration integrated system shell; 18. a reducing agent conduit; 19. a high temperature coolant delivery conduit; 20. a reducing agent spray gun; 21. a second housing; 22. a third housing; wherein 17 and 21 constitute a first annular disc, and 21 and 22 constitute a second annular disc; 23. a first annular disk temperature measuring element; 24. a second annular disk temperature measuring element; 25. a cooling liquid; 26. a fly ash ammonia concentration detection system housing; 27. a fly ash heating kettle; 28. compressed air; 29. a compressed air control valve; 30. a fly ash feed inlet; 31. a fly ash feed control valve; 32. a fly ash filter screen; 33. a high temperature resistant conduit; 34. a gas control valve; 35. a first electric heating wire; 36. a second electric heating wire; 37. a compressed air conduit; 38. a ball valve; 39. a push rod; 40. a spring; 41. a connecting rod; 42. a first load bearing frame; 43. a first fixing pin; 44. a second load-bearing frame; 45. a first fixed pulley; 46. a third bearing frame; 47. a second fixed pulley; 48. a first cable; 49. a second cable; 50. a second fixing pin; 51. a third fixing pin; 52. a fourth fixing pin; 53. a third pulley; 54. and a winding machine.
Detailed Description
Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.
As shown in fig. 1 to 8, the present embodiment provides a low load denitration method for a circulating fluidized bed boiler, comprising a boiler 1 and a denitration integrated system a, a movable rod 16 is installed at the top of the boiler 1, a fixed rod is installed at the outside of the denitration integrated system a,and the fixed rod is distributed left and right symmetrically, the denitration integrated system A comprises a denitration integrated system shell 17, a second shell 21, a third shell 22, a reducing agent pipeline 18, a high-temperature cooling liquid conveying pipeline 19, a reducing agent spray gun 20, a first annular disk temperature measuring element 23 and a second annular disk temperature measuring element 24, a lifting system B is arranged at the outer top of the boiler 1, a reducing agent liquid storage tank 2, a cooling liquid storage tank 7 and a fly ash ammonia concentration on-line detection system are arranged outside the boiler 1, the liquid storage tank 2 is respectively connected with the denitration integrated system A through a flexible material section reducing agent conveying pipe 6, a flexible material section cooling liquid conveying pipe 11 and a flexible material section high-temperature cooling liquid conveying pipe 12, the fixed rod is connected with a fixing rod 16 which can be moved up and down, and the fixing rod 16 can be controlled and regulated by the lifting system B. The low-load denitration method for the circulating fluidized bed boiler of the embodiment is characterized in that the proper temperature for denitration of the reducing agent in the boiler 1 is between 850 and 1100 ℃, urea is generally used as the reducing agent, and the urea is decomposed into NH at low temperature 3 And HNCO, the amount of HNCO generated by urea decomposition reaches the maximum at 600 ℃, and the amount of HNCO generated by urea decomposition drops sharply at 800 ℃, and HNCO is NH 3 An important substance is generated, so that the control of the temperature of the reducing agent infusion tube in the denitration system has an important influence on the improvement of the denitration efficiency.
Therefore, the reducing agent infusion tube is an effective cooling mode by using the cooling liquid.
The housing 17, the second housing 21, the third housing 22 of the denitration integrated system of the embodiment form a cavity with the reducing agent pipeline 18, the high-temperature cooling liquid conveying pipe 19 and the reducing agent spray gun 20, the reducing agent conveying pipe 18 is filled with cooling liquid 25, the reducing agent is conveyed to the reducing agent spray gun 20 by the reducing agent conveying pipe 18, the reducing agent is sprayed into the hearth after being atomized, the cooling liquid 25 is arranged around the reducing agent conveying pipe 18 and the reducing agent spray gun 20, and the cooling liquid after absorbing heat is pumped out of the denitration integrated system A by the high-temperature cooling liquid conveying pipe 19.
The shell denitration integrated system shell 17 and the second shell 21 of the embodiment form a first annular disk, the second shell 21 and the third shell 22 form a second annular disk, and the first annular disk temperature measuring element 23 and the second annular disk temperature measuring element 24 are arranged on the first annular disk and at the bottom center of the second annular disk, so that the environmental temperature where the reaction is located is monitored in real time.
The inner wall of one side of the cooling liquid storage tank 7 is connected with a cooling liquid delivery pump 8, cooling liquid 25 is pumped out of the cooling liquid storage tank 7 by the cooling liquid delivery pump 8, the cooling liquid is sequentially delivered into the denitration integrated system A through a cooling liquid flowmeter 9, a cooling liquid regulating valve 10 and a flexible material section cooling liquid delivery pipe 11, and high-temperature cooling liquid after heat absorption is delivered into the cooling liquid storage tank 7 for recirculation after being cooled in a cooling liquid cooling system 15 through a high-temperature cooling liquid outlet regulating valve 14 under the action of a water suction pump 13 through a flexible material section high-temperature cooling liquid delivery pipe 12; the reducing agent is pumped out of the reducing agent storage tank 2 by the infusion pump 3 and is conveyed into the denitration integrated system A through the reducing agent flowmeter 4, the first reducing agent regulating valve 5 and the flexible material section reducing agent conveying pipe 6 in sequence. The reducing agent is sprayed out from the center to the outer ring in the flue gas, the direction is inconsistent with the direction of the flue gas, the mixing of the reducing agent and the flue gas is facilitated, and the residence time of the reducing agent in the flue gas is prolonged. Generally, the temperature in the hearth gradually decreases from the center to the peripheral wall surfaces, a spray gun is arranged at the bottom of the denitration integrated system, partial reducing agent is directly sprayed to the center of the hearth, and the denitration efficiency is further improved by reasonably utilizing the temperature at the center. The spray gun does not adopt a direct downward mode, so that a large amount of flue gas particles are prevented from flowing into the spray gun to cause blockage to the spray gun, and the larger two convex parts of the bottom cover of the annular disk form a protection for the spray gun mouth, so that the abrasion of the flue gas particles to the spray gun is slowed down.
The cross section of the first annular disk is divided into two types of rectangle and square, the reducing agent spray guns are embedded in the annular disk, the reducing agent spray guns are symmetrically distributed, all spray guns in the first annular disk are connected to the same infusion tube, and the infusion tube in the annular disk is connected with the reducing agent infusion tube 18 of the denitration integrated system A; the spray gun outlet in the annular disk faces the wall surface of the hearth, the normal line of the spray gun outlet surface forms a certain included angle with the horizontal plane, and the normal line and the wall surface intersect at a point which is lower than the horizontal plane of the center of the annular disk. The method is used for low-load denitration of the circulating fluidized bed boiler, and the reaction temperature of the reducing agent and the flue gas is between 850 and 1100 ℃. When the boiler runs under low load, the temperature in the hearth can fluctuate, and the fixing rod can move up and down in a certain range according to the temperature shown by the temperature measuring element on the integrated system, so that the reaction is ensured to be carried out in a proper temperature range, and the reaction efficiency is improved. The periphery of the reducing agent infusion tube and the spray gun are cooled by the cooling liquid, so that premature decomposition or evaporation of the reducing agent due to high temperature is reduced, the utilization rate of the reducing agent is improved, and ammonia escape is reduced.
The cross section of the ring disc of the second ring disc is circular, a plurality of spray guns are symmetrically distributed in the ring disc, all spray guns in the ring disc are connected to the same infusion tube, and the infusion tube in the ring disc is connected with a reducing agent infusion pipeline 18 of the denitration integrated system A; the spray gun outlet in the annular disk faces the circle center, a certain included angle is formed between the normal line of the spray gun outlet surface and the horizontal plane, and the normal line and the central axis of the denitration integrated system A are converged at one point and are lower than the horizontal plane of the center of the annular disk.
The second casing 21 and the third casing 22 of this embodiment respectively form protruding portions, the projection on the horizontal plane covers the upper edge portion of the reducing agent spray gun 20, the main bodies of the first annular disk temperature measuring element 23 and the second annular disk temperature measuring element 24 are immersed in the cooling liquid 25, the temperature measuring probe penetrates through the wall surface of the metal pipe fitting to penetrate into the hearth, and the main bodies of the first annular disk temperature measuring element 23 and the second annular disk temperature measuring element 24 are connected with the external display screen and the control system of the boiler 1 through wires.
The online detection system for ammonia concentration of fly ash in this embodiment comprises compressed air 28, a fly ash feed inlet 30, a fly ash heating kettle 27, a first electric heating wire 35, a second electric heating wire 36, a fly ash filter screen 32, a high temperature resistant conduit 33, a push rod 39, a spring 40 and a spherical valve 38, wherein the spherical valve 38 is positioned at the bottom of the fly ash heating kettle 27, the fly ash feed inlet 30 is positioned at the top of the fly ash heating kettle 27, an inlet of the compressed air 28 is positioned at the side edge of the upper part of the fly ash heating kettle 27, the filter screen 32 is positioned between the fly ash heating kettle 27 and the high temperature resistant conduit 33, the fly ash heating kettle 27 is surrounded by the first electric heating wire 35, the high temperature resistant conduit 33 is surrounded by the second electric heating wire 36, the push rod 39 drives the spherical valve 38 to be in close contact with the bottom of the fly ash heating kettle 27 under the action of the spring 40 to form a sealed environment, and one end of the high temperature resistant conduit 33 is connected with an ammonia concentration meter.
The lifting system of the present embodiment includes a first load-bearing frame 42, a second load-bearing frame 44, a third load-bearing frame 46, a fourth fixing pin 52, a second fixing pin 50, a third fixing pin 51, a first fixing pin 43, a connecting rod 41, a hoist 54, a first cable 48 and a second cable 49, the first cable 48 on the hoist 54 being connected to the second fixing pin 52 sequentially around a second fixed pulley 47, a third pulley 53; the second cables 49 are divided into two groups, the two groups are symmetrically distributed, one end of each second cable is connected with a third fixing pin 51, and the other end of each second cable is connected with the first fixing pin 43 around the fixed pulleys 45 on two sides of the second bearing frame 44; the connecting rod 41 is connected with the first bearing frame 42; a second fixing pin 50 is provided on each of the load-bearing frames.
The implementation principle of the low-load denitration method for the circulating fluidized bed boiler is as follows: the denitration efficiency is improved by atomizing the reducing agent in a dilute phase region of the hearth to react with smoke particles; meanwhile, the temperature of the denitration reaction position in the hearth is detected in real time through the temperature measuring element. The reducing agent infusion tube is immersed in the cooling liquid to ensure that the reducing agent is decomposed at a proper temperature, so that the effective utilization rate of the reducing agent is improved. And the high-temperature cooling liquid is timely pumped out through the centrifugal pump, so that the cooling liquid circulation is quickened, and the effective operation of a cooling system is ensured.
While the foregoing is directed to the preferred embodiments of the present invention, it will be appreciated by those skilled in the art that various modifications and adaptations can be made without departing from the principles of the present invention, and such modifications and adaptations are intended to be comprehended within the scope of the present invention.

Claims (8)

1. The low-load denitration method for the circulating fluidized bed boiler comprises a boiler and a denitration integrated system, and is characterized in that a movable rod is arranged at the top of the boiler, a fixed rod is arranged outside the denitration integrated system and symmetrically distributed left and right, the denitration integrated system comprises a denitration integrated system shell, a second shell, a third shell, a reducing agent pipeline, a high-temperature cooling liquid conveying pipeline, a reducing agent spray gun, a first annular disk temperature measuring element and a second annular disk temperature measuring element, a lifting system is arranged at the outer top of the boiler, a reducing agent liquid storage tank, a cooling liquid storage tank and a fly ash ammonia concentration online detection system are arranged outside the boiler, the liquid storage tank is connected with the denitration integrated system through a flexible material section reducing agent conveying pipe, a flexible material section cooling liquid conveying pipe and a flexible material section high-temperature cooling liquid conveying pipe respectively, the fixed rod is connected with the movable fixed rod up and down, and the movable fixed rod is controlled and regulated by the lifting system; the height of the denitration integrated system is adjusted according to the temperatures displayed by the first annular disk temperature measuring element and the second annular disk temperature measuring element, the reducing agent spray guns are symmetrically distributed around the annular disk, and the feeding amount of the reducing agent is adjusted according to the detection result of the ammonia content; a cavity is formed among the denitration integrated system shell, the second shell, the third shell, the reducing agent pipeline, the high-temperature cooling liquid conveying pipe and the reducing agent spray gun, and cooling liquid is filled in the cavity; the denitration integrated system comprises a first annular disk, a second annular disk, a first annular disk temperature measuring element and a second annular disk temperature measuring element, wherein the first annular disk temperature measuring element and the second annular disk temperature measuring element are arranged on the first annular disk and at the bottom center of the second annular disk, and the ambient temperature where the reaction is located is monitored in real time.
2. The low-load denitration method for the circulating fluidized bed boiler according to claim 1, wherein the reducing agent is conveyed to the reducing agent spray gun through the reducing agent conveying pipe, the reducing agent is sprayed into the hearth after being atomized, the cooling liquid is arranged around the reducing agent conveying pipe and the reducing agent spray gun, and the cooling liquid after absorbing heat is pumped out of the denitration integrated system through the high-temperature cooling liquid conveying pipeline.
3. The low-load denitration method for the circulating fluidized bed boiler according to claim 1, wherein a cooling liquid conveying pump is connected to the inner wall of one side of the cooling liquid storage tank, cooling liquid is pumped out of the cooling liquid storage tank by the cooling liquid conveying pump, the cooling liquid is conveyed into the denitration integrated system sequentially through a cooling liquid flowmeter, a cooling liquid regulating valve and a flexible material section cooling liquid conveying pipe, and the cooling liquid after heat absorption is conveyed into the cooling liquid storage tank for recirculation after being cooled in the cooling liquid cooling system through a flexible material section high-temperature cooling liquid conveying pipe and a high-temperature cooling liquid outlet regulating valve under the action of a water suction pump; the reducing agent is pumped out of the reducing agent storage tank by the infusion pump and sequentially conveyed into the denitration integrated system through the reducing agent flowmeter, the first reducing agent regulating valve and the flexible material section reducing agent conveying pipe.
4. The low-load denitration method for the circulating fluidized bed boiler according to claim 1, wherein the cross section of the first annular disc is divided into two types of rectangle and square, reducing agent spray guns are embedded in the annular disc and are symmetrically distributed, all spray guns in the first annular disc are connected to the same infusion tube, and the infusion tube in the annular disc is connected with a reducing agent infusion pipeline of the denitration integrated system; the spray gun outlet in the annular disk faces the wall surface of the hearth, the normal line of the spray gun outlet surface forms a certain included angle with the horizontal plane, and the normal line and the wall surface intersect at a point which is lower than the horizontal plane of the center of the annular disk.
5. The low-load denitration method for the circulating fluidized bed boiler according to claim 1, wherein the cross section of the annular disk of the second annular disk is circular, a plurality of spray guns are arranged in the annular disk, the spray guns are symmetrically distributed, all spray guns in the annular disk are connected to the same infusion tube, and the infusion tube in the annular disk is connected with a reducing agent infusion pipeline of the denitration integrated system; the spray gun outlet in the annular disk faces the circle center, a certain included angle is formed between the normal line of the spray gun outlet surface and the horizontal plane, and the normal line and the central axis of the denitration integrated system are converged at one point and are lower than the horizontal plane of the center of the annular disk.
6. The method for low load denitration of a circulating fluidized bed boiler according to claim 4, wherein the second housing and the third housing respectively form a convex portion, a projection on a horizontal plane covers an upper edge portion of the reducing agent spray gun, the first annular disk temperature measuring element and the second annular disk temperature measuring element main body are immersed in the cooling liquid, the temperature measuring probe penetrates through a wall surface of the metal pipe fitting and goes deep into the hearth, and the first annular disk temperature measuring element and the second annular disk temperature measuring element main body are connected with an external display screen of the boiler and a control system through wires.
7. The method for denitration of circulating fluidized bed boiler according to claim 5, wherein the online detection system for ammonia concentration of fly ash comprises compressed air, a fly ash feed inlet, a fly ash heating kettle, a first electric heating wire, a second electric heating wire, a fly ash filter screen, a high temperature resistant conduit, a push rod, a spring and a spherical valve, wherein the spherical valve is positioned at the bottom of the fly ash heating kettle, the fly ash feed inlet is positioned at the top of the fly ash heating kettle, an inlet of the compressed air is positioned at the upper side of the fly ash heating kettle, the filter screen is positioned between the fly ash heating kettle and the high temperature resistant conduit, the fly ash heating kettle is surrounded by the first electric heating wire, the high temperature resistant conduit is surrounded by the second electric heating wire, the push rod drives the spherical valve to be in close contact with the bottom of the fly ash heating kettle under the action of the spring to form a sealed environment, and one end of the high temperature resistant conduit is connected with a gas ammonia concentration tester.
8. The method for low load denitration of a circulating fluidized bed boiler according to claim 7, wherein the lifting system comprises a first bearing frame, a second bearing frame, a third bearing frame, a fourth fixing pin, a second fixing pin, a third fixing pin, a first fixing pin, a connecting rod, a winch, a first cable and a second cable, and the first cable on the winch is sequentially connected with the second fixing pin by winding a second fixed pulley and a third pulley; the second mooring ropes are divided into two groups, the two groups are symmetrically distributed, one end of each second mooring rope is connected with a third fixed pin, and the other end of each second mooring rope is connected with the first fixed pin around fixed pulleys on two sides of the second bearing frame; the connecting rod is connected with the first bearing frame; and each bearing frame is provided with a second fixing pin.
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US6887439B2 (en) * 2000-12-15 2005-05-03 Delphi Technologies, Inc. Variable flow regulator for use with catalytic converters
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CN106268261B (en) * 2016-10-10 2018-12-14 福建龙净环保股份有限公司 A kind of method of SNCR denitrating flue gas
CN107398163B (en) * 2017-09-21 2023-09-29 长沙理工大学 Telescopic and swinging SNCR (selective non-catalytic reduction) reducing agent injection device
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