CN114225682A - 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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Publication number
CN114225682A
CN114225682A CN202111269071.8A CN202111269071A CN114225682A CN 114225682 A CN114225682 A CN 114225682A CN 202111269071 A CN202111269071 A CN 202111269071A CN 114225682 A CN114225682 A CN 114225682A
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China
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reducing agent
cooling liquid
denitration
integrated system
conveying pipe
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CN202111269071.8A
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CN114225682B (en
Inventor
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

Abstract

The invention discloses a low-load denitration system and a method for a circulating fluidized bed boiler, which comprises a boiler and a denitration integrated system, the top of the boiler is provided with a movable rod piece, the outside of the denitration integrated system is provided with a fixed rod, the fixed rods are distributed in bilateral symmetry, 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 ring plate temperature measuring element and a second ring plate temperature measuring element, a lifting system is arranged at the outer top of the boiler, and a reducing agent liquid storage tank, a cooling liquid storage tank and an online detection system for the ammonia concentration of the fly ash 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 method 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 of circulating fluidized bed boiler in low-load operation, in particular to a low-load denitration method and a fly ash ammonia concentration online detection method for a circulating fluidized bed boiler.
Background
With the proposal of a double-carbon target and a strategy, the traditional thermal power deep peak regulation is gradually normalized, thermal power generation mainly comprising a circulating fluidized bed boiler is gradually converted into a supplementary standby row and column in a certain period in a part of areas, the circulating fluidized bed boiler is also gradually adjusted from full load adjustment to low-load operation, the denitration reaction and the temperature zone of an SNCR denitration system matched with the circulating fluidized bed boiler are difficult to match, so that the denitration efficiency is reduced, and the improvement and the upgrade of the SNCR system are urgently needed to be realized by innovative technologies.
The SNCR denitration technology is called selective non-catalytic reduction denitration technology, and atomized reducing agent is sprayed into flue gas at a proper temperature under the action of no catalyst, so that nitrogen oxide in the flue gas is reduced into nitrogen and water. Ammonia, urea and hydroammonia are commonly used reducing agents, and among them, urea is widely used in terms of safety and price. Although the 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 ℃.
Under normal load and full load operation conditions of the circulating fluidized bed boiler, the temperature of the horizontal flue can meet the temperature condition required by the technology, so that the traditional denitration position is at the horizontal flue. And the temperature of the horizontal flue position is lower than the temperature required by the reaction when the boiler operates under the condition of low load, so how to ensure the reaction temperature is the key for realizing the flexible switching between high load and low load of the circulating fluidized bed boiler. At present, the boiler is mainly modified by spraying a spray gun into a hearth through the wall surface of the boiler to react with flue gas, and the boiler has the following defects: firstly, the temperature fluctuation in the hearth is large, and the position of the spray gun is relatively fixed, so that the influence of the temperature is large; secondly, the ascending speed of the airflow in the central area of the hearth is high, 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 low.
Disclosure of Invention
The invention provides a low-load denitration method for a circulating fluidized bed boiler, which is beneficial to solving the problems of the SNCR low-load denitration method of the existing circulating fluidized bed boiler, solving the problem that the position of a spray gun is fixed and is difficult to adapt to the large-amplitude temperature fluctuation in a hearth and being beneficial to matching a proper temperature zone for non-denitration reaction under the low-load condition; the invention solves the problem that the atomized reducing agent is blown to the wall surface and can not 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 beneficial to accurately obtaining amine escape information, can further improve the precision of controlling the injection quantity of a reducing agent, and reduces the negative influence caused by excessive injection of the reducing agent.
To solve the above technical problem, an embodiment of the present invention provides the following solutions:
a low-load denitration method for a circulating fluidized bed boiler comprises a boiler and a denitration integrated system, wherein a movable rod piece is arranged at the top of the boiler, fixed rods are arranged outside the denitration integrated system and are symmetrically distributed in the left and right directions, 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 disc temperature measuring element and a second annular disc 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 concentration online detection system are arranged outside the boiler, the liquid storage tank is respectively 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, and the fixed rods are connected with the fixed rods in an up-and-down moving manner, and the fixed rod can move up and down and is controlled and adjusted by the lifting system.
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 the inside of the cavity is filled with cooling liquid.
Preferably, the reducing agent transfer tube conveys the reducing agent to the reducing agent spray gun, the reducing agent is atomized and then sprayed into the hearth, the cooling liquid is arranged around the reducing agent transfer tube 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.
Preferably, the shell of the shell denitration integrated system and the second shell form a first ring disc, the second shell and the third shell form a second ring disc, and the first ring disc temperature measuring element and the second ring disc temperature measuring element are arranged on the first ring disc and at the center of the bottom of the second ring disc to monitor the ambient temperature of the reaction 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 delivered to the denitration integrated system through a cooling liquid flow meter, a cooling liquid adjusting valve and a flexible material section cooling liquid delivery pipe in sequence, and the cooling liquid absorbing heat is 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 adjusting valve under the action of a water pump and is delivered to the cooling liquid storage tank for recirculation; the reducing agent is pumped out of the reducing agent storage tank by the infusion pump and conveyed to the denitration integrated system through the reducing agent flowmeter, the first reducing agent regulating valve and the flexible material section reducing agent conveying pipe in sequence.
Preferably, the cross section of the annular disc of the first annular disc is divided into a rectangular shape and a square shape, 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 liquid conveying pipe, and the liquid conveying pipe in the annular disc is connected with a reducing agent liquid conveying pipe of the denitration integrated system; the outlet of the spray gun in the annular disc faces the wall surface of the hearth, the normal line of the outlet surface of the spray gun forms a certain included angle with the horizontal plane, and the normal line intersects with the wall surface at a point which is lower than the central horizontal plane of the annular disc.
Preferably, the cross section of the annular disc of the second annular disc is circular, a plurality of spray guns are arranged in the annular disc and are symmetrically distributed, all the spray guns in the annular disc are connected to the same liquid conveying pipe, and the liquid conveying pipe in the annular disc is connected with a reducing agent liquid conveying pipe of the denitration integrated system; the outlet of the spray gun in the annular disc faces the circle center, a certain included angle is formed between the normal line of the outlet surface of the spray gun 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 central horizontal plane of the annular disc.
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 and extends 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 leads.
Preferably, the flying ash contains ammonia concentration on-line measuring system includes compressed air, flying ash feed inlet, flying ash heating kettle, first electric heating wire, second electric heating wire, flying ash filter screen, high temperature resistant pipe, ejector pin, spring and ball valve, ball valve is located flying ash heating kettle's bottom, and the flying ash feed inlet is located flying ash heating kettle's top, compressed air's entry is located flying ash heating kettle's upper portion side, the filter screen is located between flying ash heating kettle and the high temperature resistant pipe, and flying ash heating kettle is surrounded by first electric heating wire, high temperature resistant pipe is surrounded by second electric heating wire, the ejector pin drives ball valve and flying ash heating kettle's bottom in close contact with under the spring action and forms sealed environment, the one end of high temperature resistant pipe is connected with gaseous ammonia concentration determination appearance.
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 sequentially winds a second fixed pulley, and the third pulley 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 group is connected with a third fixing pin, and the other end of each group is connected with the first fixing pin by winding 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, the fixed rod which can move up and down is arranged at the top of the hearth and extends into the dilute phase region, the denitration integrated system with the reducing agent spray gun is fixedly connected with the fixed rod, and the height of the denitration integrated system is adjusted within a certain range according to the temperature displayed by 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;
a plurality of spray guns are arranged in the ring disc, so that the contact area of the reducing agent and the flue gas is increased. Meanwhile, the denitration efficiency is improved to the maximum extent by changing the direction of the nozzle opening and fully utilizing the characteristic of high central temperature of the hearth, the reducing agent conveying pipe and the spray gun are cooled in the hearth through the circulation of cooling liquid, the reducing agent is prevented from being decomposed too early due to high temperature, and the utilization rate of the reducing agent is effectively improved;
the high-temperature cooling liquid is pumped away by a water pump through a liquid conveying pipe which directly reaches the bottom of the denitration integrated system, the circulation of the cooling liquid is accelerated, the system is effectively cooled, solid particles are collected on line, the ammonia content in the fly ash is measured in real time by utilizing the characteristics of decomposition of ammonia salt at high temperature and escape of ammonia gas, the feeding amount of a reducing agent is effectively fed back and adjusted, the effective utilization rate of the reducing agent is improved, the lifting system uses a telescopic arm stroke amplification principle, and the lifting mechanism is controlled 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 present invention.
FIG. 2 is a schematic diagram of the ejector structure of the denitration system provided by the present invention.
Fig. 3 is a top view of a first ring plate according to an embodiment of the present invention.
Fig. 4 is a top view of a second structure corresponding to the first ring plate according to the embodiment of the present invention.
Fig. 5 is a top view of a second corresponding structure of a ring disc 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 present invention.
Fig. 7 is a schematic structural diagram of a lifting device of a denitration integrated system according to an embodiment of the present invention.
Fig. 8 is a flow chart of a feedback regulation 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 reductant 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 coolant storage tank; 8. a coolant delivery pump; 9. a coolant flow meter; 10. a coolant regulating valve; 11. a flexible material segment coolant delivery tube; 12. a flexible material section high-temperature cooling liquid conveying pipe; 13. a water pump; 14. a high-temperature cooling liquid outlet regulating valve; 15. a coolant cooling system; 16. a movable rod member; 17. a denitration integrated system housing; 18. a reductant line; 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 form a first ring disc, and 21 and 22 form a second ring disc; 23. a first annular disk temperature measuring element; 24. a second ring disk temperature measuring element; 25. cooling liquid; 26. a shell of a fly ash ammonia-containing concentration detection system; 27. heating the fly ash in a kettle; 28. compressing air; 29. a compressed air control valve; 30. a fly ash feed port; 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 top rod; 40. a spring; 41. a connecting rod; 42. a first bearing frame; 43. a first fixing pin; 44. a second 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. a hoisting 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, which includes a boiler 1 and a denitration integrated system a, wherein a movable rod 16 is installed on the top of the boiler 1, fixed rods are installed outside the denitration integrated system a, and the fixed rods are symmetrically distributed in the left-right direction, the denitration integrated system a includes a denitration integrated system housing 17, a second housing 21, a third housing 22, a reducing agent pipeline 18, a high-temperature cooling liquid conveying pipeline 19, a reducing agent spray gun 20, a first annular disc temperature measuring element 23 and a second annular disc temperature measuring element 24, a lifting system B is installed on the outer top of the boiler 1, a reducing agent liquid storage tank 2, a cooling liquid storage tank 7 and an ammonia-containing fly ash concentration online detection system are installed 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 fixing rod is connected with a fixing rod 16 which can move up and down, and the fixing rod 16 which can move up and down is controlled and adjusted by a lifting system B. In the method for denitration under low load of circulating fluidized bed boiler of the embodiment, the suitable 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 temperature3And HNCO, the quantity of the HNCO decomposed by the urea reaches the maximum at 600 ℃, and the temperature reaches 800 DEG CThe amount of HNCO generated by urea decomposition is reduced sharply, and HNCO is also NH3An important substance is generated, so that the control of the temperature of a reducing agent liquid conveying pipe in a denitration system has a very important influence on the improvement of the denitration efficiency.
Therefore, the coolant is an effective cooling mode for the reducing agent liquid conveying pipe.
In this embodiment, cavities are formed among the housing 17, the second housing 21, the third housing 22, the reducing agent pipeline 18, the high-temperature cooling liquid conveying pipe 19, and the reducing agent spray gun 20, the interior of the cavity is filled with the cooling liquid 25, the reducing agent conveying pipe 18 conveys the reducing agent to the reducing agent spray gun 20, the reducing agent is atomized and then sprayed into the hearth, 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 extracted from the denitration integrated system a through the high-temperature cooling liquid conveying pipe 19.
The shell 17 and the second shell 21 of the integrated shell denitration system of the embodiment form a first ring plate, the second shell 21 and the third shell 22 form a second ring plate, and the first ring plate temperature measuring element 23 and the second ring plate temperature measuring element 24 are arranged on the first ring plate and at the center of the bottom of the second ring plate to monitor the ambient temperature of the reaction in real time.
A cooling liquid delivery pump 8 is connected to the inner wall of one side of the cooling liquid storage tank 7 in the embodiment, cooling liquid 25 is pumped out of the cooling liquid storage tank 7 by the cooling liquid delivery pump 8, the cooling liquid is delivered to the denitration integrated system a sequentially through a cooling liquid flowmeter 9, a cooling liquid adjusting valve 10 and a flexible material section cooling liquid delivery pipe 11, and the high-temperature cooling liquid absorbing heat is delivered to 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 adjusting 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 from the reducing agent storage tank 2 by the infusion pump 3 and is conveyed to the denitration integrated system A through the reducing agent flow meter 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 of the reducing agent is not consistent with the direction of the flue gas, the reducing agent and the flue gas are mixed, and the retention time of the reducing agent in the flue gas is prolonged. The temperature in general furnace reduces to wall all around from the center gradually, and denitration integrated system bottom is equipped with the spray gun, and partial reductant directly spouts furnace center department, and rational utilization center department temperature further improves denitration efficiency. The spray gun does not adopt a direct downward mode to avoid blocking the spray gun due to the fact that a large number of smoke particles flow into the spray gun, the projecting parts of the bottom covers of the two larger ring disks form protection for the spray gun mouth, and abrasion of the smoke particles to the spray gun is slowed down.
The cross section of the annular disc of the first annular disc is divided into a rectangular shape and a square shape, 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 liquid conveying pipe, and the liquid conveying pipe in the annular disc is connected with a reducing agent liquid conveying pipe 18 of a denitration integrated system A; the outlet of the spray gun in the annular disc faces the wall surface of the hearth, the normal line of the outlet surface of the spray gun forms a certain included angle with the horizontal plane, and the normal line intersects with the wall surface at a point which is lower than the central horizontal plane of the annular disc. The method is used for the low-load denitration method 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 operates at low load, the temperature in the hearth fluctuates, and the fixing rod capable of moving up and down 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 carried out in a proper temperature range, and the reaction efficiency is improved. The reducing agent liquid conveying pipe and the spray gun are cooled by the cooling liquid around, 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 arranged in the ring disc and are symmetrically distributed, all the spray guns in the ring disc are connected to the same liquid conveying pipe, and the liquid conveying pipe in the ring disc is connected with a reducing agent liquid conveying pipe 18 of the denitration integrated system A; the outlet of the spray gun in the ring disc faces the circle center, a certain included angle is formed between the normal line of the outlet surface of the spray gun 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 central horizontal plane of the ring disc.
The second shell 21 and the third shell 22 of the embodiment form a convex part respectively, the projection on the horizontal plane covers the upper edge part of the reducing agent spray gun 20, the main bodies of the first ring plate temperature measuring element 23 and the second ring plate temperature measuring element 24 are immersed in the cooling liquid 25, the temperature measuring probe penetrates through the wall surface of the metal pipe to penetrate into a hearth, and the main bodies of the first ring plate temperature measuring element 23 and the second ring plate temperature measuring element 24 are connected with an external display screen and a control system of the boiler 1 through leads.
The fly ash ammonia concentration online detection system of this embodiment includes compressed air 28, fly ash feed inlet 30, fly ash heating kettle 27, first electric heating wire 35, second electric heating wire 36, fly ash filter screen 32, high temperature resistant pipe 33, ejector pin 39, spring 40 and ball valve 38, ball valve 38 is located the bottom of fly ash heating kettle 27, and fly ash feed inlet 30 is located the top of fly ash heating kettle 27, the entry of compressed air 28 is located the upper portion side of fly ash heating kettle 27, filter screen 32 is located between fly ash heating kettle 27 and high temperature resistant pipe 33, and fly ash heating kettle 27 is surrounded by first electric heating wire 35, high temperature resistant pipe 33 is surrounded by second electric heating wire 36, ejector pin 39 drives ball valve 38 and fly ash heating kettle 27's bottom in close contact with and forms sealed environment under the effect of spring 40, the one end of high temperature resistant pipe 33 is connected with ammonia concentration determination appearance.
The lifting system of the embodiment comprises a first bearing frame 42, a second bearing frame 44, a third bearing frame 46, a fourth fixed pin 52, a second fixed pin 50, a third fixed pin 51, a first fixed pin 43, a connecting rod 41, a winch 54, a first cable 48 and a second cable 49, wherein the first cable 48 on the winch 54 is sequentially connected with the second fixed pin 52 by winding a second fixed pulley 47 and a third pulley 53; the second cables 49 are divided into two groups, wherein the two groups are symmetrically distributed, one end of each group is connected with a third fixing pin 51, and the other end of each group is connected with the first fixing pin 43 by winding the fixed pulleys 45 on the two sides of the second bearing frame 44; the connecting rod 41 is connected with the first bearing frame 42; each bearing frame is provided with a second fixing pin 50.
The invention discloses a low-load denitration method for a circulating fluidized bed boiler, which is implemented according to the following principle: the denitration efficiency is improved by atomizing the reducing agent in the dilute phase zone of the hearth to react with the flue gas particles; and simultaneously, the temperature of the denitration reaction position in the hearth is detected in real time through a temperature measuring element. The reducing agent liquid conveying pipe 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. The high-temperature cooling liquid is timely pumped away through the centrifugal pump, so that the circulation of the cooling liquid is accelerated, and the effective operation of a cooling system is guaranteed.
While the foregoing is directed to the preferred embodiment of the present invention, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the appended claims.

Claims (10)

1. A low-load denitration method for a circulating fluidized bed boiler comprises a boiler and a denitration integrated system, and is characterized in that a movable rod piece is arranged at the top of the boiler, fixed rods are arranged outside the denitration integrated system and are distributed in a bilateral symmetry manner, 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 ring plate temperature measuring element and a second ring plate 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 respectively 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, the fixed rod is connected with the fixed rod capable of moving up and down, and the fixed rod capable of moving up and down is controlled and adjusted by the lifting system.
2. The low-load denitration method for the circulating fluidized bed boiler according to claim 1, wherein cavities are formed among the denitration integrated system casing, the second casing, the third casing, the reducing agent pipeline, the high-temperature cooling liquid delivery pipe and the reducing agent spray gun, and the interiors of the cavities are filled with cooling liquid.
3. The low-load denitration method for the circulating fluidized bed boiler according to claim 2, wherein the reducing agent liquid conveying pipe conveys the reducing agent to the reducing agent spray gun, the reducing agent is atomized and then sprayed into the hearth, the cooling liquid is arranged around the reducing agent liquid 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 pipe.
4. The method for low-load denitration of the circulating fluidized bed boiler according to claim 3, wherein the denitration integrated system shell and the second shell form a first ring disk, the second shell and the third shell form a second ring disk, and the first ring disk temperature measuring element and the second ring disk temperature measuring element are arranged on the first ring disk and in the center of the bottom of the second ring disk to monitor the ambient temperature in which the reaction is performed in real time.
5. The low-load denitration method for the circulating fluidized bed boiler according to claim 4, wherein a cooling liquid delivery pump is connected to an inner wall of one side of the cooling liquid storage tank, the cooling liquid is pumped out of the cooling liquid storage tank by the cooling liquid delivery pump, the cooling liquid is delivered to the denitration integration system through a cooling liquid flowmeter, a cooling liquid adjusting valve and a flexible material section cooling liquid delivery pipe in sequence, and the cooling liquid absorbing heat is delivered to 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 adjusting valve under the action of a water pump; the reducing agent is pumped out of the reducing agent storage tank by the infusion pump and conveyed to the denitration integrated system through the reducing agent flowmeter, the first reducing agent regulating valve and the flexible material section reducing agent conveying pipe in sequence.
6. The low-load denitration method for the circulating fluidized bed boiler according to claim 4, wherein the cross section of the first annular disc is divided into a rectangular shape and a square shape, 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 liquid conveying pipe, and the liquid conveying pipe in the annular disc is connected with a reducing agent liquid conveying pipeline of the denitration integrated system; the outlet of the spray gun in the annular disc faces the wall surface of the hearth, the normal line of the outlet surface of the spray gun forms a certain included angle with the horizontal plane, and the normal line intersects with the wall surface at a point which is lower than the central horizontal plane of the annular disc.
7. The low-load denitration method for the circulating fluidized bed boiler according to claim 4, wherein the cross section of the annular disc of the second annular disc is circular, a plurality of spray guns are arranged in the annular disc and are symmetrically distributed, all the spray guns in the annular disc are connected to the same liquid conveying pipe, and the liquid conveying pipe in the annular disc is connected with a reducing agent liquid conveying pipe of the denitration integrated system; the outlet of the spray gun in the annular disc faces the circle center, a certain included angle is formed between the normal line of the outlet surface of the spray gun 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 central horizontal plane of the annular disc.
8. The method for denitration by low load of the circulating fluidized bed boiler according to claim 6, wherein the second outer shell and the third outer shell are respectively formed with 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 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 a display screen and a control system outside the boiler through conducting wires.
9. The low load denitration method for the circulating fluidized bed boiler according to claim 7, the fly ash ammonia-containing concentration online detection system comprises compressed air, a fly ash feeding hole, 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, an ejector 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 feeding port is positioned at the top of the fly ash heating kettle, the inlet of the compressed air is positioned at 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, and the fly ash heating kettle is surrounded by a first electric heating wire, the high temperature resistant conduit is surrounded by a second electric heating wire, the ejector 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 guide pipe is connected with a gas ammonia concentration tester.
10. The method for low-load denitration of the circulating fluidized bed boiler according to claim 9, 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, wherein the first cable on the winch is sequentially wound around a second fixed pulley, and the third pulley is connected with the second fixing pin; the second mooring ropes are divided into two groups, the two groups are symmetrically distributed, one end of each group is connected with a third fixing pin, and the other end of each group is connected with the first fixing pin by winding 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.
CN202111269071.8A 2021-10-29 2021-10-29 Low-load denitration method for circulating fluidized bed boiler Active CN114225682B (en)

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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20020073697A1 (en) * 2000-12-15 2002-06-20 Jankowski Paul E. Variable flow regulator for use with catalytic converters
CN204816208U (en) * 2015-05-29 2015-12-02 孙永宏 Outer SNCR denitrification facility of layer furnace stove
CN106268261A (en) * 2016-10-10 2017-01-04 福建龙净环保股份有限公司 A kind of method of SNCR denitrating flue gas
CN107398163A (en) * 2017-09-21 2017-11-28 长沙理工大学 A kind of scalable and shuttle-type SNCR reducing agent injection apparatus
CN110762520A (en) * 2019-10-24 2020-02-07 浙江新中港清洁能源股份有限公司 Efficient desulfurization and denitrification method for coal combustion
CN213590149U (en) * 2020-10-26 2021-07-02 山东首丰环保设备有限公司 SCR (Selective catalytic reduction) denitration device for boiler flue gas

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20020073697A1 (en) * 2000-12-15 2002-06-20 Jankowski Paul E. Variable flow regulator for use with catalytic converters
CN204816208U (en) * 2015-05-29 2015-12-02 孙永宏 Outer SNCR denitrification facility of layer furnace stove
CN106268261A (en) * 2016-10-10 2017-01-04 福建龙净环保股份有限公司 A kind of method of SNCR denitrating flue gas
CN107398163A (en) * 2017-09-21 2017-11-28 长沙理工大学 A kind of scalable and shuttle-type SNCR reducing agent injection apparatus
CN110762520A (en) * 2019-10-24 2020-02-07 浙江新中港清洁能源股份有限公司 Efficient desulfurization and denitrification method for coal combustion
CN213590149U (en) * 2020-10-26 2021-07-02 山东首丰环保设备有限公司 SCR (Selective catalytic reduction) denitration device for boiler flue gas

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