CN112588108A - Flue gas denitration system and method under full-load working condition of boiler - Google Patents
Flue gas denitration system and method under full-load working condition of boiler Download PDFInfo
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- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 title claims abstract description 149
- 239000003546 flue gas Substances 0.000 title claims abstract description 149
- 238000000034 method Methods 0.000 title claims abstract description 13
- 239000004202 carbamide Substances 0.000 claims abstract description 71
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Chemical compound NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 claims abstract description 68
- 238000000197 pyrolysis Methods 0.000 claims abstract description 50
- 238000002347 injection Methods 0.000 claims abstract description 36
- 239000007924 injection Substances 0.000 claims abstract description 36
- 239000007921 spray Substances 0.000 claims abstract description 14
- 238000005507 spraying Methods 0.000 claims abstract description 12
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 claims description 50
- MWUXSHHQAYIFBG-UHFFFAOYSA-N Nitric oxide Chemical compound O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 claims description 37
- 230000009471 action Effects 0.000 claims description 19
- 238000006243 chemical reaction Methods 0.000 claims description 17
- 229910021529 ammonia Inorganic materials 0.000 claims description 14
- 230000003197 catalytic effect Effects 0.000 claims description 11
- 238000006479 redox reaction Methods 0.000 claims description 11
- 230000003068 static effect Effects 0.000 claims description 11
- 239000000243 solution Substances 0.000 claims description 9
- 239000000779 smoke Substances 0.000 claims description 7
- 239000010881 fly ash Substances 0.000 claims description 4
- 238000013461 design Methods 0.000 abstract description 2
- 230000004048 modification Effects 0.000 abstract description 2
- 238000012986 modification Methods 0.000 abstract description 2
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 3
- 235000011114 ammonium hydroxide Nutrition 0.000 description 3
- 238000002425 crystallisation Methods 0.000 description 3
- 230000008025 crystallization Effects 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
- 230000007062 hydrolysis Effects 0.000 description 3
- 238000006460 hydrolysis reaction Methods 0.000 description 3
- 238000012423 maintenance Methods 0.000 description 3
- 238000010248 power generation Methods 0.000 description 3
- 239000003638 chemical reducing agent Substances 0.000 description 2
- 238000005260 corrosion Methods 0.000 description 2
- 230000007797 corrosion Effects 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 238000013459 approach Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000010531 catalytic reduction reaction Methods 0.000 description 1
- 239000003245 coal Substances 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 206010022000 influenza Diseases 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 238000006722 reduction reaction Methods 0.000 description 1
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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
- B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
- B01D53/86—Catalytic processes
- B01D53/8621—Removing nitrogen compounds
- B01D53/8625—Nitrogen oxides
- B01D53/8631—Processes characterised by a specific device
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- 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
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- Environmental & Geological Engineering (AREA)
- Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Biomedical Technology (AREA)
- Analytical Chemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Treating Waste Gases (AREA)
- Exhaust Gas Treatment By Means Of Catalyst (AREA)
Abstract
The invention relates to a flue gas denitration system and a flue gas denitration method under the full-load working condition of a boiler, wherein the system comprises a high-temperature flue gas bypass which is connected and arranged outside a flue of the boiler; the high-temperature flue gas bypass comprises a high-temperature flue gas outlet flue, a urea direct injection pyrolysis flue, a high-temperature flue gas inlet flue and a low-load bypass inlet flue; one end of the high-temperature flue gas leading-out flue is connected to the steering chamber of the boiler rear flue, and the other end of the high-temperature flue gas leading-out flue is connected with the urea direct injection pyrolysis flue; the other end of the urea direct injection pyrolysis flue is respectively connected with one end of a high-temperature flue gas introduction flue and one end of a low-load bypass introduction flue; the other end of the high-temperature flue gas introduction flue is connected with an inlet flue of the economizer; the other end of the low-load bypass introducing flue is connected with the low-temperature flue gas main flue; the urea direct injection pyrolysis flue is connected with a urea spray gun; the spraying direction of the urea spray gun is vertical to the flow direction of flue gas in the urea direct-spraying pyrolysis flue. The invention has reasonable design and convenient modification, and simultaneously meets the requirements of economy and safety to realize flue gas denitration of the boiler unit under the full-load working condition.
Description
Technical Field
The invention relates to the field of boiler denitration, in particular to a flue gas denitration system and method under a full-load working condition of a boiler.
Background
With the increase of the national investment on new energy power generation such as hydropower, wind power, solar power generation and the like, the occupation ratio of thermal power generation in the power industry is reduced year by year. The original basic load of the thermal power unit is gradually changed into a power grid peak regulation power supply, and when a large number of existing coal-fired units run at low load, the smoke temperature at a denitration inlet cannot meet the minimum input temperature of an SCR (selective catalytic reduction) system, so that low-load NO (nitric oxide) is causedxThe emission exceeds the standard, thereby influencing the deep peak regulation of the unit. In order to meet the requirements of national environmental protection policies and achieve the purpose of flexible peak regulation, related equipment needs to be modified. At present, the most adopted technical route is to newly add a high-temperature flue gas bypass, introduce the high-temperature flue gas into a denitration inlet flue, mix the flue gas and meet the input temperature of an SCR system, thereby reaching NOxAnd (4) ultralow emission. Meanwhile, the selection of the SCR denitration reducing agent of the coal-fired unit is basically concentrated in three directions: 1) liquid ammonia, the most commonly used denitration reducing agent at present, has the main flow of liquid ammonia evaporator → ammonia injection grid, and has the advantages of simple process, low initial investment and operation cost, but high safety risk because the liquid ammonia is a major hazard source. 2) The ammonia water mainly comprises an ammonia water evaporator-ammonia → ammonia spraying grid, and has the advantages of simple process and low operation cost, but the ammonia water is expensive in transportation cost, large in storage and transportation equipment, high in leakage risk and high in safety risk. 3) Urea, mainly consisting of urea pyrolysis, hydrolysis and direct urea injection. The urea hydrolysis system is complex, the ammonia production process has poor following load variability, the initial investment is large, the later maintenance amount is large, and the corrosion and crystallization of the pipeline are easy to occur; the urea pyrolysis usually adopts a hot primary air electric heater or a gas-gas heat exchanger, the operation cost is high, and the system is complex and is easy to cause crystallization; both of these approaches fail to satisfy the complexity of practical coal-fired unit flexibility peak shavingAnd the reduction performance of the SCR denitration device, and the requirements of economy and simplicity.
Disclosure of Invention
Aiming at the problems in the prior art, the invention provides a flue gas denitration system and method under the full-load working condition of a boiler, which have the advantages of simple structure, reasonable design, convenience in modification and realization of flue gas denitration under the full-load working condition of a boiler unit due to the requirements of economy and safety.
The invention is realized by the following technical scheme:
a flue gas denitration system under the full-load working condition of a boiler comprises a high-temperature flue gas bypass which is connected and arranged outside a flue of the boiler;
the high-temperature flue gas bypass comprises a high-temperature flue gas outlet flue, a urea direct injection pyrolysis flue, a high-temperature flue gas inlet flue and a low-load bypass inlet flue;
one end of the high-temperature flue gas leading-out flue is connected with a turning chamber of a boiler rear flue, and the other end of the high-temperature flue gas leading-out flue is connected with a urea direct injection pyrolysis flue; the other end of the urea direct injection pyrolysis flue is respectively connected with one end of a high-temperature flue gas introduction flue and one end of a low-load bypass introduction flue; the other end of the high-temperature flue gas introduction flue is connected and arranged at an inlet flue of the economizer; the other end of the low-load bypass introducing flue is connected with the low-temperature flue gas main flue;
a urea spray gun is connected to the urea direct injection pyrolysis flue; the spraying direction of the urea spray gun is perpendicular to the flow direction of flue gas in the urea direct injection pyrolysis flue.
Furthermore, a diversion trench is arranged in the flue at the joint of the low-load bypass introducing flue and the low-temperature flue gas main flue; a mixed flue is arranged behind the diversion trench; the outlet of the mixing flue is connected with the denitration inlet flue, a guide plate is arranged at the joint, and a static mixer is arranged in the denitration inlet flue behind the guide plate.
Furthermore, a first expansion joint, a first shutoff baffle door and a first adjusting baffle door are sequentially arranged in the high-temperature flue gas leading-out flue along the flow direction of the flue gas.
Furthermore, a second shutoff damper and a second expansion joint are sequentially arranged in the high-temperature flue gas introducing flue along the flow direction of the flue gas.
Furthermore, a fly ash separator is arranged at the joint of the high-temperature flue gas introduction flue and the boiler rear flue steering chamber, and a high-temperature fan is arranged at the joint of the high-temperature flue gas introduction flue and the urea direct injection pyrolysis flue.
Furthermore, a third expansion joint and a third shut-off baffle door are sequentially arranged in the low-load bypass introducing flue along the flow direction of the flue gas.
Furthermore, a second adjusting baffle plate door is arranged between the low-temperature flue gas main flue and the flue behind the economizer.
Furthermore, a urea solution metering module is arranged on the urea spray gun.
A method for denitrating flue gas under full-load working condition of a boiler comprises the following steps,
step 1, extracting high-temperature flue gas from a rear flue turning chamber through a high-temperature flue gas leading-out flue;
step 2, in the urea direct injection pyrolysis flue, urea in high-temperature flue gas is injected by a urea spray gun to carry out pyrolysis reaction to generate ammonia;
and 3, introducing the generated ammonia gas into the flue along with the high-temperature flue gas or introducing the generated ammonia gas into the flue along with the low-load bypass, uniformly mixing the ammonia gas with the nitrogen oxide in the flue gas, and then performing oxidation-reduction reaction under the action of a catalytic reactor to finish the flue gas denitration operation.
Further, in step 3, when the boiler load is a basic load and the denitration inlet flue meets the lowest ammonia injection temperature, high-temperature flue gas is led out of the flue and directly injected into the pyrolysis flue to form a flue gas channel, ammonia gas generated by the reaction is led into the flue through the high-temperature flue gas and then enters the mixing flue through the economizer, and is uniformly mixed with nitrogen oxides in the flue gas under the action of the guide plate and the static mixer and then undergoes an oxidation-reduction reaction under the action of the catalytic reactor;
when the boiler load is low load and the denitration inlet flue cannot meet the lowest ammonia spraying temperature, the high-temperature flue gas leading-out flue and the urea direct-injection pyrolysis flue form a flue gas channel, ammonia gas generated by reaction is led into the flue through a low-load bypass to be mixed with flue gas in a low-temperature flue gas main flue, then the mixed flue gas enters the mixing flue, and is uniformly mixed with nitrogen oxide in the flue gas under the action of a guide plate and a static mixer and then subjected to oxidation-reduction reaction under the action of a catalytic reactor.
Compared with the prior art, the invention has the following beneficial technical effects:
according to the flue gas denitration system under the full-load working condition of the boiler, the high-temperature flue gas bypass is added, the urea direct injection pyrolysis technology is adopted, the high-temperature flue gas is introduced into the bypass to carry out urea pyrolysis, and different introduction flues are respectively communicated with the inlet of the economizer or the denitration inlet, so that flue gas denitration of a boiler unit under the full-load working condition is realized.
Furthermore, a urea spray gun and an auxiliary metering module are arranged in the high-temperature flue gas duct, so that the urea is accurately metered and directly sprayed, and is pyrolyzed in advance, and the heating surface of the original flue duct cannot be damaged.
The invention discloses a flue gas denitration method under the full-load working condition of a boiler, which is characterized in that high-temperature flue gas is extracted from a rear flue turning chamber and is introduced into an economizer inlet flue and a denitration inlet flue, the position of a flue gas introduction port is switched according to the load and the flue gas temperature of the boiler, the reaction temperature is provided for direct injection pyrolysis of urea by controlling the quantity of the high-temperature flue gas introduced, and ammonia gas is generated by pyrolysis reaction of urea solution in a urea pyrolysis chamber, so that the flue gas denitration under the full-load working condition of the boiler is realized. Meanwhile, the full-load flue gas denitration system of the boiler under the urea direct injection technology reduces influence on boiler efficiency to the maximum extent, and also solves the problem of application of the urea direct injection pyrolysis technology to a coal-fired unit.
Drawings
FIG. 1 is a schematic diagram of a system according to an embodiment of the present invention.
In the figure: 1-fly ash separator, 2-first expansion joint, 3-first shutoff damper, 4-first regulation damper, 5-high temperature fan, 6-high temperature flue gas outlet flue, 7-urea spray gun, 8-urea solution metering module, 9-urea direct injection pyrolysis flue, 10-second expansion joint, 11-second shutoff damper, 12-high temperature flue gas inlet flue, 13-third expansion joint, 14-third shutoff damper, 15-low load bypass inlet flue, 16-static mixer, 17-diversion trench, 18-diversion plate, 19-mixing flue, 20-low temperature flue gas main flue, 21-second regulation damper and 22-economizer.
Detailed Description
The present invention will now be described in further detail with reference to specific examples, which are intended to be illustrative, but not limiting, of the invention.
The invention provides a flue gas denitration system under the full-load working condition of a boiler, which comprises a high-temperature flue gas leading-out flue 6, a high-temperature flue gas leading-in flue 12, a low-load bypass leading-in flue 15, a low-temperature flue gas main flue 20 and a mixed flue 19, a fly ash separator 1 at the boiler side, a first expansion joint 2, a first shutoff damper 3, a first adjusting damper 4, a second expansion joint 10, a second shutoff damper 11, a third expansion joint 13, a third shutoff damper 14, a urea direct injection pyrolysis flue 9, a urea spray gun 7, a urea solution metering module 8, a high-temperature fan 5, a second adjusting damper 21, a diversion trench 17, a diversion plate 18, a static mixer 16, corresponding measuring instruments and the like, wherein the high-temperature flue gas leading-out flue 12, the low-load bypass leading-in.
According to the system, the reaction temperature is provided for direct injection pyrolysis of urea by controlling the amount of the high-temperature flue gas led out, and the urea solution is subjected to pyrolysis reaction in the urea pyrolysis chamber to generate ammonia gas, so that flue gas denitration under the full-load working condition of a boiler is realized;
when the boiler load is a basic load, when a denitration inlet flue meets the lowest ammonia injection temperature, opening a first shutoff damper 3, a first adjusting damper 4 and a second shutoff damper 11 at a high-temperature flue gas introduction flue 12 at a high-temperature flue gas introduction flue 6, closing a third shutoff damper 14 at a low-load bypass introduction flue 15, observing the flow rate of the flue gas according to an instrument, if the flow rate of the flue gas cannot meet the requirement of urea pyrolysis, opening a high-temperature fan 5, adjusting the flow rate of the flue gas to be in an optimal state, spraying a urea solution into a pyrolysis chamber for pyrolysis reaction, introducing the generated ammonia gas into the flue 12 through the high-temperature flue gas, entering a mixing flue 19 through an economizer 22, uniformly mixing the ammonia gas with nitrogen oxides in the flue gas under the action of a guide plate 18 and a static mixer 16, and then carrying out oxidation-reduction reaction under the action of a catalytic reactor;
when the boiler load is low load and the denitration inlet flue can not meet the lowest ammonia spraying temperature, a first shutoff damper 3 at the high-temperature flue gas leading-out flue 6, a first adjusting damper 4 and a third shutoff damper 14 at the low-load bypass leading-in flue 15 are opened, a second shutoff damper 11 at the high-temperature flue gas leading-in flue 12 is closed, observing the flue gas flow according to an instrument, adjusting and adjusting a second adjusting damper 21 if the flue gas flow cannot meet the requirement of urea pyrolysis, adjusting the flue gas flow to reach the optimal state, spraying a urea solution into a pyrolysis chamber for pyrolysis reaction, introducing ammonia gas generated by the reaction into a flue 15 through a low-load bypass, mixing the ammonia gas with the flue gas of a low-temperature flue gas main flue 20, then enters a mixing flue 19, is uniformly mixed with nitrogen oxide in the flue gas under the action of a guide plate 18 and a static mixer 16, and then is subjected to oxidation reduction reaction under the action of a catalytic reactor.
The system effectively avoids the corrosion phenomenon of the heating surface caused by direct injection of the urea in the furnace, and simultaneously utilizes the low-quality flue gas heat source to carry out pyrolysis on the urea solution, thereby saving the operation cost; compared with urea hydrolysis and traditional urea pyrolysis, the urea direct injection system needs to provide a proper reaction temperature interval and a structural space on a coal burner unit, has the advantages of simplicity, safety, less initial investment, small later maintenance amount and the like, solves the problems of system complexity and large later maintenance amount of the former two modes, and avoids the problem of easy crystallization.
On the basis of the system, the invention also provides a flue gas denitration method under the full-load working condition of the boiler, which comprises the following steps,
step 1, extracting high-temperature flue gas from a rear flue turning chamber through a high-temperature flue gas leading-out flue 6;
step 2, in the urea direct injection pyrolysis flue 9, urea in high-temperature flue gas is injected by a urea spray gun 7 to carry out pyrolysis reaction to generate ammonia gas;
and 3, introducing the generated ammonia gas into the flue 12 along with the high-temperature flue gas or introducing the generated ammonia gas into the flue 15 along with the low-load bypass, uniformly mixing the ammonia gas with the nitrogen oxide in the flue gas, and then performing an oxidation reduction reaction under the action of a catalytic reactor to finish the flue gas denitration operation.
In step 3, when the boiler load is a basic load and the denitration inlet flue meets the lowest ammonia injection temperature, high-temperature flue gas is led out of the flue 6 and directly injected into the pyrolysis flue 9 to form a flue gas channel, ammonia gas generated by reaction is led into the flue 12 through the high-temperature flue gas and then enters the mixing flue 19 through the economizer 22, and is uniformly mixed with nitrogen oxides in the flue gas under the action of the guide plate 18 and the static mixer 16 and then undergoes an oxidation-reduction reaction under the action of the catalytic reactor;
when the boiler load is low load and the denitration inlet flue cannot meet the lowest ammonia spraying temperature, the high-temperature flue gas is led out of the flue 6 and the urea direct injection pyrolysis flue 9 to form a flue gas channel, the ammonia gas generated by the reaction is led into the flue 15 through a low-load bypass to be mixed with the flue gas of the low-temperature flue gas main flue 20, then enters the mixing flue 19, is uniformly mixed with the nitrogen oxide in the flue gas under the action of the guide plate 18 and the static mixer 16, and then is subjected to oxidation reduction reaction under the action of the catalytic reactor.
Claims (10)
1. A flue gas denitration system under a full-load working condition of a boiler is characterized by comprising a high-temperature flue gas bypass which is connected and arranged outside a flue of the boiler;
the high-temperature flue gas bypass comprises a high-temperature flue gas outlet flue (6), a urea direct injection pyrolysis flue (9), a high-temperature flue gas inlet flue (12) and a low-load bypass inlet flue (15);
one end of the high-temperature flue gas leading-out flue (6) is connected and arranged at the position of the boiler rear flue turning chamber, and the other end of the high-temperature flue gas leading-out flue is connected with a urea direct injection pyrolysis flue (9); the other end of the urea direct injection pyrolysis flue (9) is respectively connected with one end of a high-temperature flue gas introduction flue (12) and one end of a low-load bypass introduction flue (15); the other end of the high-temperature flue gas introduction flue (12) is connected and arranged at an inlet flue of the economizer (22); the other end of the low-load bypass introducing flue (15) is connected with a low-temperature flue gas main flue (20);
a urea spray gun (7) is connected and arranged on the urea direct injection pyrolysis flue (9); the spraying direction of the urea spray gun (7) is perpendicular to the flow direction of flue gas in the urea direct-spraying pyrolysis flue (9).
2. The flue gas denitration system of the boiler under the full-load working condition according to claim 1, wherein a diversion trench (17) is arranged in the flue at the joint of the low-load bypass introduction flue (15) and the low-temperature flue gas main flue (20); a mixed flue (19) is arranged behind the diversion trench (17); the outlet of the mixed flue (19) is connected with the denitration inlet flue, a guide plate (18) is arranged at the joint, and a static mixer (16) is arranged in the denitration inlet flue behind the guide plate (18).
3. The system for denitrating the smoke of the boiler under the full-load working condition according to the claim 1, wherein a first expansion joint (2), a first shutoff damper (3) and a first adjusting damper (4) are sequentially arranged in the high-temperature smoke leading-out flue (6) along the smoke flow direction.
4. The system for denitrating the smoke of the boiler under the full-load working condition according to the claim 1, characterized in that the high-temperature smoke is introduced into the flue (12) and is sequentially provided with a second shutoff damper (11) and a second expansion joint (10) along the smoke flow direction.
5. The system for denitration of flue gas under full load condition of boiler according to claim 1, wherein a fly ash separator (1) is arranged at the joint of said high temperature flue gas introduction flue (12) and said boiler back flue turning chamber, and a high temperature fan (5) is arranged at the joint of said high temperature flue gas introduction flue (12) and said urea direct injection pyrolysis flue (9).
6. The denitration system for the full-load working condition of the boiler according to claim 1, wherein the low-load bypass introducing flue (15) is provided with a third expansion joint (13) and a third shut-off damper door (14) in sequence along the flue gas flow direction.
7. The system for denitration of flue gas of boiler under full load condition as claimed in claim 1, wherein a second adjusting damper door (21) is arranged between said low temperature flue gas main flue (20) and flue behind economizer (22).
8. The system for denitration of flue gas of a boiler under full load condition of claim 1, wherein a urea solution metering module (8) is arranged on the urea spray gun (7).
9. A method for denitrating flue gas of a boiler under full-load working condition, which is characterized in that based on any one system of the claims 1-8, the method comprises the following steps,
step 1, extracting high-temperature flue gas from a rear flue turning chamber through a high-temperature flue gas leading-out flue (6);
step 2, in the urea direct injection pyrolysis flue (9), urea in high-temperature flue gas is injected by a urea spray gun (7) to carry out pyrolysis reaction to generate ammonia;
and 3, introducing the generated ammonia gas into the flue (12) along with the high-temperature flue gas or into the flue (15) along with the low-load bypass, uniformly mixing the ammonia gas with the nitrogen oxide in the flue gas, and performing oxidation-reduction reaction under the action of a catalytic reactor to finish the flue gas denitration operation.
10. The method for denitrating the flue gas under the full-load working condition of the boiler according to claim 1, wherein in the step 3, when the boiler load is a basic load and a denitration inlet flue meets the lowest ammonia injection temperature, the high-temperature flue gas is led out of a flue (6) and is directly injected into a pyrolysis flue (9) to form a flue gas channel, the ammonia gas generated by the reaction is led into the flue (12) through the high-temperature flue gas, then enters a mixing flue (19) through an economizer (22), is uniformly mixed with the nitrogen oxides in the flue gas under the action of a guide plate (18) and a static mixer (16), and then is subjected to an oxidation-reduction reaction under the action of a catalytic reactor;
when the boiler load is low load and the denitration inlet flue cannot meet the lowest ammonia spraying temperature, the high-temperature flue gas is led out of the flue (6) and the urea direct injection pyrolysis flue (9) to form a flue gas channel, the ammonia gas generated by the reaction is led into the flue (15) through a low-load bypass and is mixed with the flue gas of the low-temperature flue gas main flue (20), then the mixed flue (19) enters the mixing flue, and is uniformly mixed with the nitrogen oxide in the flue gas under the action of the guide plate (18) and the static mixer (16) and then subjected to oxidation-reduction reaction under the action of the catalytic reactor.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114288852A (en) * | 2022-02-16 | 2022-04-08 | 西安西热锅炉环保工程有限公司 | Wide-load coal-fired boiler denitration system and working method thereof |
| CN114797465A (en) * | 2022-04-19 | 2022-07-29 | 东方电气集团东方锅炉股份有限公司 | SCR denitrification facility suitable for under wide load |
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| CN114797465A (en) * | 2022-04-19 | 2022-07-29 | 东方电气集团东方锅炉股份有限公司 | SCR denitrification facility suitable for under wide load |
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