CN110841442A - Denitration device and method - Google Patents
Denitration device and method Download PDFInfo
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- CN110841442A CN110841442A CN201911337172.7A CN201911337172A CN110841442A CN 110841442 A CN110841442 A CN 110841442A CN 201911337172 A CN201911337172 A CN 201911337172A CN 110841442 A CN110841442 A CN 110841442A
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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
- B01D53/343—Heat recovery
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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
- B01D53/46—Removing components of defined structure
- B01D53/54—Nitrogen compounds
- B01D53/56—Nitrogen oxides
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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
- B01D53/75—Multi-step processes
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- 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
- B01D2258/025—Other waste gases from metallurgy plants
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- 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
Abstract
The invention discloses a denitration device and a denitration method. The denitration device provided by the invention can fully utilize the heat energy of the high-temperature flue gas and the low-temperature flue gas output by the sintering machine, mix the high-temperature flue gas with a part of the low-temperature flue gas to enable the temperature of the mixed flue gas to reach the reaction temperature of medium-low temperature SCR denitration, then mix the remaining low-temperature flue gas with the mixed gas subjected to medium-low temperature SCR denitration, enter the dry-method desulfurization, dedusting and denitration integrated machine for desulfurization and denitration, and then discharge the gas into the atmosphere. The invention makes full use of the temperature of the flue gas output by the sintering machine, and is matched with the dry desulfurization, dedusting and denitration integrated machine, thereby avoiding heating the flue gas, saving energy and reducing the denitration cost of the sintering flue gas.
Description
Technical Field
The invention relates to the technical field of steel sintering equipment, in particular to a denitration device and a denitration method.
Background
At present, in non-electric industries such as steel sintering and the like, medium and low temperature SCR denitration with heating is mainly selected for denitration. However, the temperature of the mixed flue gas discharged by the sintering machine is 130-180 ℃, and the requirement of the working temperature of the medium-low temperature SCR denitration is not more than or equal to 180 ℃ can not be met. Therefore, a flue gas heating device is required to increase the temperature of the flue gas to 180-320 ℃ so as to meet the working requirement of the SCR catalyst. The flue gas heating device mainly uses blast furnace/converter gas, the operation cost of the flue gas heating device is too high, and the flue gas heating device occupies more than half of the total operation cost of medium and low temperature SCR denitration, so that the SCR denitration cost of the steel sintering industry is high.
Therefore, how to reduce the denitration cost of the sintering flue gas is a technical problem to be solved urgently by the technical personnel in the field.
Disclosure of Invention
In view of the above, a first object of the present invention is to provide a denitration apparatus, which can reduce the denitration cost of sintering flue gas.
It is a second object of the present invention to provide a denitration method.
In order to achieve the first object, the present invention provides the following solutions:
a denitration device comprises a high-temperature air box group, a first low-temperature air box group, a second low-temperature air box group, a medium-low-temperature SCR reactor, a dry-method desulfurization, dedusting and denitration integrated machine, a first flue gas regulating valve and a first flue gas regulating valve;
the inlet of the high-temperature air box group is used for inputting high-temperature flue gas output by a sintering machine, the inlet of the first low-temperature air box group and the inlet of the second low-temperature air box group are both used for inputting low-temperature flue gas output by the sintering machine, the temperature of the high-temperature flue gas is higher than the reaction temperature of the medium-low-temperature SCR reactor, and the temperature of the low-temperature flue gas is lower than the reaction temperature of the medium-low-temperature SCR reactor;
the first smoke regulating valve and the second smoke regulating valve are arranged at the outlet of the first low-temperature air box group in parallel;
the high-temperature air box group is communicated with an outlet of the first flue gas regulating valve, an outlet of the first flue gas regulating valve is communicated with an inlet of the medium-low temperature SCR reactor, an outlet of the medium-low temperature SCR reactor is communicated with an inlet of the dry desulfurization, dedusting and denitration integrated machine, and an outlet of the dry desulfurization, dedusting and denitration integrated machine is used for gas emission;
and the outlet of the second low-temperature air box group is communicated with the outlet of the second flue gas regulating valve and is communicated with the inlet of the dry desulfurization, dedusting and denitration integrated machine.
In a specific embodiment, the denitration apparatus further comprises a first dust remover;
the inlet of the first dust remover is communicated with the outlet of the first flue gas regulating valve and the outlet of the high-temperature air box group, and the outlet of the first dust remover is communicated with the inlet of the medium-low-temperature SCR reactor.
In another embodiment, the denitration apparatus further comprises a second dust remover;
and the inlet of the second dust remover is communicated with the outlet of the second flue gas regulating valve, the outlet of the second low-temperature air box group and the outlet of the medium-low temperature SCR reactor, and the outlet of the second dust remover is communicated with the inlet of the dry desulfurization, dedusting and denitration integrated machine.
In another specific embodiment, the denitration device further comprises a first induced draft fan;
an inlet of the first induced draft fan is communicated with an outlet of the medium-low temperature SCR reactor;
the export of first draught fan with the export of second low temperature bellows group the export of second flue gas governing valve reaches the entry of second dust remover all switches on.
In another specific embodiment, the denitration device further comprises a sintering main exhaust fan;
and the inlet of the sintering main exhaust fan and the outlet of the sintering main exhaust fan are respectively communicated with the outlet of the second dust remover and the inlet of the dry desulfurization, dedusting and denitration integrated machine.
In another specific embodiment, the denitration device further comprises a second induced draft fan;
and the inlet of the second induced draft fan and the outlet of the second induced draft fan are respectively communicated with the outlet of the dry desulfurization, dedusting and denitration integrated machine and the inlet of the chimney.
In another embodiment, the first denitrifier in the medium-low temperature SCR reactor comprises ammonia,
and/or
Liquid ammonia is added into the reaction kettle,
and/or
Urea.
In another specific embodiment, a second denitration agent and a denitration absorbent are arranged in the dry desulfurization, dedusting and denitration integrated machine;
the second denitrifier comprises oxidizing gas desulfurization nitrate,
and/or
The oxidized liquid is desulfurized and nitre is removed,
and/or
Oxidized solid desulfurized nitric;
the denitration absorbent is an alkaline absorbent; and/or
The dry desulfurization, dust removal and denitration integrated machine adopts a circulating fluidized bed technology.
In another specific embodiment, the outlets of the high temperature wind box group, the first low temperature wind box group and the second low temperature wind box group are all provided with adjusting windshields.
The various embodiments according to the invention can be combined as desired, and the embodiments obtained after these combinations are also within the scope of the invention and are part of the specific embodiments of the invention.
Without being limited to any theory, it can be seen from the above disclosure that, in use, the denitration device disclosed by the invention enters high-temperature flue gas output by the sintering machine into the high-temperature air box group, and low-temperature flue gas output by the sintering machine respectively enters into the first low-temperature air box group and the second low-temperature air box group, and the mixed flue gas temperature formed by mixing the high-temperature flue gas and the low-temperature flue gas can reach the reaction temperature in the medium-low-temperature SCR reactor by respectively adjusting the opening degrees of the first flue gas adjusting valve and the second flue gas adjusting valve, so as to carry out medium-low-temperature SCR denitration; and mixing the mixed flue gas subjected to medium-low temperature SCR denitration with the residual low-temperature flue gas coming out of the first low-temperature air box group and the low-temperature flue gas coming out of the low-temperature air box group, feeding the mixed flue gas into a dry desulfurization, dedusting and denitration integrated machine for desulfurization and denitration, and finally discharging the gas subjected to desulfurization and denitration by the dry desulfurization, dedusting and denitration integrated machine. The denitration device provided by the invention can fully utilize the heat energy of the high-temperature flue gas and the low-temperature flue gas output by the sintering machine, mix the high-temperature flue gas with a part of the low-temperature flue gas to enable the temperature of the mixed flue gas to reach the reaction temperature of medium-low temperature SCR denitration, then mix the remaining low-temperature gas with the mixed gas subjected to medium-low temperature SCR denitration, enter the dry-method desulfurization, dedusting and denitration integrated machine for desulfurization and denitration, and then discharge the gas into the air. The invention makes full use of the temperature of the flue gas output by the sintering machine, and is matched with the dry desulfurization, dedusting and denitration integrated machine, thereby avoiding heating the flue gas, saving energy and reducing the denitration cost of the sintering flue gas.
In order to achieve the second object, the present invention provides the following solutions:
a denitration method comprising the steps of:
dividing flue gas output by a sintering machine into high-temperature flue gas and low-temperature flue gas respectively, wherein the temperature of the high-temperature flue gas is higher than the reaction temperature of the medium-low temperature SCR reactor, and the temperature of the low-temperature flue gas is lower than the reaction temperature of the medium-low temperature SCR reactor;
adjusting the mixing ratio of the low-temperature flue gas and the high-temperature flue gas to enable the temperature of the mixed first mixed flue gas to reach the reaction temperature of the medium-low-temperature SCR reactor, and inputting the first mixed flue gas into the medium-low-temperature SCR reactor to carry out medium-low-temperature SCR denitration;
mixing the first mixed flue gas subjected to denitration by the medium-low temperature SCR reactor with the rest low-temperature flue gas, and feeding the mixed second mixed flue gas into a dry-method desulfurization, dedusting and denitration integrated machine for secondary denitration;
and discharging the gas discharged from the dry desulfurization, dedusting and denitration integrated machine.
Without being limited to any theory, it can be seen from the above disclosure that the denitration method disclosed by the invention mixes the low-temperature flue gas and the high-temperature flue gas in a certain proportion, so that the mixed flue gas can reach the reaction temperature of medium-low temperature SCR denitration, and enters the medium-low temperature SCR reactor for reaction, thereby realizing the full utilization of heat. And the residual low-temperature flue gas is subjected to secondary denitration by the dry-method desulfurization, dedusting and denitration integrated machine, so that the high cost caused by heating the low-temperature flue gas is avoided.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
Fig. 1 is a schematic structural diagram of a denitration apparatus provided by the present invention.
Wherein, in fig. 1:
the device comprises a high-temperature air box group 1, a first low-temperature air box group 2, a second low-temperature air box group 3, a medium-low-temperature SCR reactor 4, a dry desulfurization, dedusting and denitration integrated machine 5, a first flue gas regulating valve 6, a second flue gas regulating valve 7, a sintering machine 8, a first dust remover 9, a second dust remover 10, a first induced draft fan 11, a sintering main exhaust fan 12, a second induced draft fan 13 and a chimney 14.
Detailed Description
In order to make those skilled in the art better understand the technical solution of the present invention, the following detailed description of the present invention is provided with reference to fig. 1 and the detailed description.
Example one
The invention discloses a denitration device, wherein the denitration device comprises an air box group, a medium-low temperature SCR reactor 4, a dry desulfurization, dedusting and denitration integrated machine 5, a first flue gas regulating valve 6 and a first flue gas regulating valve 6.
Specifically, the bellows group includes a high temperature bellows group 1, a first low temperature bellows group 2, and a second low temperature bellows group 3. Specifically, the number of the high-temperature bellows group 1, the inlet of the first low-temperature bellows group 2, and the second low-temperature bellows group 3 may be any number, depending on the number of outlets of the sintering machine 8. The temperature of the flue gas in the air box group gradually rises along the moving direction of the conveyor belt of the sintering machine 8. That is to say, high temperature bellows group 1, the flue gas temperature in first low temperature bellows group 2 and the second low temperature bellows group 3 steadilys decrease, selects the low temperature flue gas in the second low temperature bellows group 3 and the high temperature flue gas cooperation in the high temperature bellows group 1, has realized that more mixed flue gas can carry out the denitration reaction in well low temperature SCR reactor 4 for the sintering flue gas volume that needs carry out the denitration in dry desulfurization dust removal denitration all-in-one machine 5 reduces, has reduced the denitration cost.
The inlet of the high-temperature air box group 1 is used for inputting high-temperature flue gas output by the sintering machine 8, and the inlet of the first low-temperature air box group 2 and the inlet of the second low-temperature air box group 3 are both used for inputting low-temperature flue gas output by the sintering machine 8.
It should be noted that the temperature of the high-temperature flue gas is higher than the reaction temperature of the medium-low temperature SCR reactor 4, and the temperature of the low-temperature flue gas is lower than the reaction temperature of the medium-low temperature SCR reactor 4.
The outlet of the first low-temperature air box group 2 is provided with a first flue gas regulating valve 6 and a second flue gas regulating valve 7 in parallel. The high-temperature air box group 1 is communicated with an outlet of the first flue gas regulating valve 6, an outlet of the first flue gas regulating valve 6 is communicated with an inlet of the medium-low temperature SCR reactor 4, an outlet of the medium-low temperature SCR reactor 4 is communicated with an inlet of the dry desulfurization, dedusting and denitration integrated machine 5, an outlet of the dry desulfurization, dedusting and denitration integrated machine 5 is used for gas emission, and the gas meets the emission standard. Specifically, the outlet of the dry desulfurization, dedusting and denitration integrated machine 5 can be communicated with the chimney 14, so that the gas is discharged from the chimney 14. The outlet of the second low-temperature air box group 3 is communicated with the outlet of the second flue gas regulating valve 7 and is communicated with the inlet of the dry desulfurization, dedusting and denitration integrated machine 5.
The integrated desulfurization, dedusting and denitration machine 5 is a common desulfurization and denitration device.
When the denitration device disclosed by the invention is used, high-temperature flue gas output by a sintering machine 8 enters a high-temperature air box group 1, low-temperature flue gas output by the sintering machine 8 respectively enters a first low-temperature air box group 2 and a second low-temperature air box group 3, and the temperature of first mixed flue gas formed by mixing the high-temperature flue gas and the low-temperature flue gas can reach the reaction temperature in a medium-low temperature SCR reactor 4 by respectively adjusting the opening degrees of a first flue gas adjusting valve 6 and a second flue gas adjusting valve 7, so that medium-low temperature SCR denitration is carried out; the first mixed flue gas after the middle-low temperature SCR denitration is mixed with the residual low-temperature flue gas coming out of the first low-temperature air box group 2 and the low-temperature flue gas coming out of the second low-temperature air box group 3 to form second mixed flue gas, the second mixed flue gas enters the dry desulfurization, dedusting and denitration integrated machine 5 for desulfurization and denitration, and finally the second mixed flue gas is subjected to desulfurization and denitration by the dry desulfurization, dedusting and denitration integrated machine 5, and the gas meeting the emission standard is discharged and is discharged to the atmosphere through a chimney 14.
The denitration device provided by the invention can fully utilize the heat energy of the high-temperature flue gas and the low-temperature flue gas output by the sintering machine 8, mix the high-temperature flue gas and a part of the low-temperature flue gas to enable the temperature of the mixed flue gas to reach the reaction temperature of medium-low temperature SCR denitration, then mix the remaining low-temperature flue gas with the mixed gas subjected to medium-low temperature SCR denitration, enter the dry-method desulfurization, dedusting and denitration integrated machine 5 for desulfurization and denitration, and then discharge the gas into the atmosphere. The invention makes full use of the temperature of the flue gas output by the sintering machine 8, and is matched with the dry desulfurization, dedusting and denitration integrated machine 5, thereby avoiding heating the flue gas, saving energy and reducing the denitration cost of the sintering flue gas.
Example two
In the second embodiment provided by the present invention, the denitration device in this embodiment has a similar structure to that in the first embodiment, and the same parts are not repeated, and only differences are introduced.
In this embodiment, the invention specifically discloses that the denitration device further comprises a first dust remover 9, an inlet of the first dust remover 9 is communicated with an outlet of the first flue gas regulating valve 6 and an outlet of the high-temperature air box group 1, and an outlet of the first dust remover 9 is communicated with an inlet of the medium-low temperature SCR reactor 4. On the one hand, the first dust remover 9 is used for fully mixing the high-temperature flue gas output by the high-temperature air box group 1 and the low-temperature flue gas output by the first flue gas regulating valve 6, and on the other hand, the first dust remover 9 is used for separating dust and impurities in the mixed flue gas, so that the mixed flue gas entering the medium-low-temperature SCR reactor 4 is pure. Specifically, the first dust remover 9 is a multi-tube dust remover, and it should be noted that the first dust remover 9 is not limited to be a multi-tube dust remover, and other dust removers capable of meeting the use requirement also belong to the protection scope of the present invention.
Further, the invention discloses a denitration device which further comprises a second dust remover 10, wherein an inlet of the second dust remover 10 is communicated with an outlet of the medium-low temperature SCR reactor 4, an outlet of the second flue gas regulating valve 7 and an outlet of the second low-temperature air box group 3, and an outlet of the second dust remover 10 is communicated with an inlet of the dry-method desulfurization, dust removal and denitration integrated machine 5. Specifically, the second dust collector 10 is a nose electric dust collector, and it should be noted that the second dust collector 10 is not limited to be a nose electric dust collector, and other dust collectors capable of meeting the use requirement also belong to the protection scope of the present invention.
Further, the invention discloses a denitration device which further comprises a first induced draft fan 11, wherein an inlet of the first induced draft fan 11 is communicated with an outlet of the medium-low temperature SCR reactor 4, and an outlet of the first induced draft fan 11 is communicated with an outlet of the second low-temperature air box group 3, an outlet of the second flue gas regulating valve 7 and an inlet of the second dust remover 10. The first induced draft fan 11 can overcome the system resistance in the denitration device, and the first mixed gas is convenient to be led out.
Further, the invention discloses a denitration device which further comprises a sintering main exhaust fan 12, wherein an inlet of the sintering main exhaust fan 12 and an outlet of the sintering main exhaust fan 12 are respectively communicated with an outlet of the second dust remover 10 and an inlet of the dry-method desulfurization, dedusting and denitration integrated machine 5. The sintering main exhaust fan 12 is used for pumping the second mixed flue gas dedusted by the second deduster 10 into the dry desulfurization, dedusting and denitration integrated machine 5.
Further, the invention discloses a denitration device which further comprises a second induced draft fan 13, wherein an inlet of the second induced draft fan 13 and an outlet of the second induced draft fan 13 are respectively communicated with an outlet of the dry desulfurization, dedusting and denitration integrated machine 5 and an inlet of a chimney 14. The second induced draft fan 13 is convenient for pass through the chimney 14 with the gas that satisfies emission standard after the denitration of dry process desulfurization dust removal denitration integration machine 5 and discharges in the atmosphere.
Specifically, the invention discloses that the first denitration agent in the medium-low temperature SCR reactor 4 can only comprise ammonia water, liquid ammonia or urea, and can also simultaneously comprise any two or three of the ammonia water, the liquid ammonia and the urea.
Specifically, the invention discloses a dry desulfurization, dedusting and denitration integrated machine 5 internally provided with a second denitration agent and a denitration absorbent. Specifically, the second denitration agent may include any one, any two, or all of oxidized gas desulfurization nitrate, oxidized liquid desulfurization nitrate, and oxidized solid desulfurization nitrate.
The oxidizing gas denitrifying agent can be ozone or ClO2And the oxidation-type liquid desulfurization nitrate is liquid such as sodium chlorite, sodium hypochlorite, sodium chlorate, potassium permanganate, hydrogen peroxide and the like, and the oxidation-type solid desulfurization nitrate is solid such as sodium chlorite, sodium hypochlorite, sodium chlorate, potassium permanganate, hydrogen peroxide and the like.
The denitration absorbent is alkaline absorbent, specifically, CaO and Ca (OH)2、MgO、Mg(OH)2、NaOH、Na2CO3And the like.
Further, the invention discloses that an adjusting windshield is arranged at the outlet of the first low-temperature air box group 2.
In this embodiment, the working temperature of the medium-low temperature SCR reactor 4 is greater than or equal to 180 ℃ and less than or equal to 320 ℃, and the number of the bellows groups is 5, wherein the high temperature bellows group 1 is 1, and the number of the first low temperature bellows group 2 and the second low temperature bellows group 3 is 2. As shown in fig. 1.
The flue gas of the sintering machine 8 is led out from each air box group, the flue gas is divided into two groups of low-temperature flue gas and high-temperature flue gas, and the flue gas is regulated by regulating each first flue gasThe opening degree of the valve 6 and the second flue gas regulating valve 7 is used for regulating the mixing proportion of the flue gas of each air box, so that the temperature of the mixed first mixed flue gas is ensured to be more than 180 ℃, and the temperature requirement of medium-low temperature SCR denitration is met. The first mixed flue gas firstly enters a multi-tube dust remover for dust removal and then enters the medium-low temperature SCR reactor 4 for denitration reaction, and the concentration of NOx at the outlet of the medium-low temperature SCR reactor 4 is controlled to be 20mg/Nm3The following. The denitrated first mixed flue gas is mixed with the denitrated low-temperature flue gas through a denitration induced draft fan to form second mixed flue gas, and the concentration of NOx in the second mixed flue gas is 200mg/Nm3The following. Then enters a machine head for electric precipitation, enters a dry desulfurization, dedusting and denitration integrated machine through a sintering main exhaust fan 12, and carries out second-stage denitration through an oxidation absorption method, so that the concentration of NOx in outlet flue gas can be stabilized at 50mg/Nm3The purified flue gas is then discharged into a chimney 14 by a second induced draft fan 13.
EXAMPLE III
A certain 180m2Sintering machine 8 used the denitration apparatus of the present invention and had a flue gas amount of 650000Nm3H (standard condition); the concentration of NOx in the flue gas is about 300mg/Nm3Ammonia water is used as a denitration reducing agent.
The denitration device disclosed by the invention is adopted for flue gas treatment, the temperature of the first mixed flue gas is controlled to reach 260 ℃ through the first flue gas regulating valve 6 and the second flue gas regulating valve 7, and the concentration of NOx is 211mg/Nm3. The concentration of NOx is controlled to be 20mg/Nm after passing through the medium-low temperature SCR reactor 43The following. Mixing the denitrated first mixed flue gas with the denitrated low-temperature flue gas, wherein the NOx concentrations of the two flue gases are respectively 20mg/Nm3And 278mg/Nm3And the NOx concentration of the mixed second mixed flue gas is about 170mg/Nm3. Then the second mixed flue gas enters a dry desulfurization, dedusting and denitration integrated machine 5 for second-stage denitration reaction, and the concentration of NOx at the outlet after the second-stage denitration is less than 50mg/Nm3。
Example four
A certain 230m2The sintering machine 8 uses the denitration device disclosed by the invention, and the flue gas volume is 920000Nm3H (standard condition); the concentration of NOx in the flue gas is about 250mg/Nm3Ammonia water is used as a denitration reducing agent.
By adopting the device for flue gas treatment, the temperature of the first mixed gas is controlled to reach 260 ℃ through the first flue gas regulating valve 6 and the second flue gas regulating valve 7, and the concentration of NOx is 258mg/Nm3. The concentration of NOx is controlled to be 20mg/Nm after passing through the medium-low temperature SCR reactor 43The following. The denitrated first mixed flue gas is mixed with the denitrated low-temperature flue gas, and the NOx concentration of the two flue gases is respectively less than 20mg/Nm3And 330mg/Nm3The NOx concentration of the mixed second mixed smoke is less than 200mg/Nm3. Then the flue gas enters a dry desulfurization, dedusting and denitration integrated machine 5 for secondary denitration reaction, and the concentration of NOx at an outlet after the secondary denitration is less than 50mg/Nm3。
EXAMPLE five
The invention provides a denitration method, which comprises the following steps:
step S1: the flue gas output by the sintering machine 8 is divided into high-temperature flue gas and low-temperature flue gas.
Specifically, the temperature of the high-temperature flue gas is higher than the reaction temperature of the medium-low temperature SCR reactor 4, and the temperature of the low-temperature flue gas is lower than the reaction temperature of the medium-low temperature SCR reactor 4.
In order to facilitate the leading-out of the high-temperature flue gas and the low-temperature flue gas, an air box is arranged at the outlet of the sintering machine 8, and the flue gas is led out through the air box.
Step S2: and adjusting the mixing ratio of the low-temperature flue gas and the high-temperature flue gas to enable the temperature of the mixed first mixed flue gas to reach the reaction temperature of the medium-low temperature SCR reactor 4, inputting the first mixed flue gas into the medium-low temperature SCR reactor 4, and performing medium-low temperature SCR denitration.
Step S3: the first mixed flue gas subjected to denitration by the medium-low temperature SCR reactor 4 is mixed with the rest low-temperature flue gas, and the mixed second mixed flue gas enters the dry-method desulfurization, dedusting and denitration integrated machine 5 to be subjected to secondary denitration.
Step S4: and (3) discharging the gas discharged from the dry desulfurization, dust removal and denitration integrated machine 5 into the atmosphere.
According to the denitration method disclosed by the invention, the low-temperature flue gas and the high-temperature flue gas are mixed according to a certain proportion, so that the mixed flue gas can reach the reaction temperature of medium and low-temperature SCR denitration, and enters the medium and low-temperature SCR reactor 4 for reaction, and the full utilization of heat is realized. And the residual low-temperature flue gas is subjected to secondary denitration by the dry desulfurization, dedusting and denitration integrated machine 5, so that the high denitration cost caused by heating the low-temperature flue gas is avoided.
The terms "first", "second", and the like in the present invention are used for descriptive distinction and have no other special meaning.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and inventive features disclosed herein.
Claims (10)
1. A denitration device is characterized by comprising a high-temperature air box group, a first low-temperature air box group, a second low-temperature air box group, a medium-low temperature SCR reactor, a dry desulfurization, dedusting and denitration integrated machine, a first flue gas regulating valve and a second flue gas regulating valve;
the inlet of the high-temperature air box group is used for inputting high-temperature flue gas output by a sintering machine, the inlet of the first low-temperature air box group and the inlet of the second low-temperature air box group are both used for inputting low-temperature flue gas output by the sintering machine, the temperature of the high-temperature flue gas is higher than the reaction temperature of the medium-low-temperature SCR reactor, and the temperature of the low-temperature flue gas is lower than the reaction temperature of the medium-low-temperature SCR reactor;
the first smoke regulating valve and the second smoke regulating valve are arranged at the outlet of the first low-temperature air box group in parallel;
the high-temperature air box group is communicated with an outlet of the first flue gas regulating valve, an outlet of the first flue gas regulating valve is communicated with an inlet of the medium-low temperature SCR reactor, an outlet of the medium-low temperature SCR reactor is communicated with an inlet of the dry desulfurization, dedusting and denitration integrated machine, and an outlet of the dry desulfurization, dedusting and denitration integrated machine is used for gas emission;
and the outlet of the second low-temperature air box group is communicated with the outlet of the second flue gas regulating valve and is communicated with the inlet of the dry desulfurization, dedusting and denitration integrated machine.
2. The denitration apparatus according to claim 1, further comprising a first dust remover;
the inlet of the first dust remover is communicated with the outlet of the first flue gas regulating valve and the outlet of the high-temperature air box group, and the outlet of the first dust remover is communicated with the inlet of the medium-low-temperature SCR reactor.
3. The denitration apparatus according to claim 2, further comprising a second dust remover;
and the inlet of the second dust remover is communicated with the outlet of the second flue gas regulating valve, the outlet of the second low-temperature air box group and the outlet of the medium-low temperature SCR reactor, and the outlet of the second dust remover is communicated with the inlet of the dry desulfurization, dedusting and denitration integrated machine.
4. The denitration device according to claim 3, further comprising a first induced draft fan;
an inlet of the first induced draft fan is communicated with an outlet of the medium-low temperature SCR reactor;
the export of first draught fan with the export of second low temperature bellows group the export of second flue gas governing valve reaches the entry of second dust remover all switches on.
5. The denitration apparatus according to claim 4, further comprising a sintering main exhaust fan;
and the inlet of the sintering main exhaust fan and the outlet of the sintering main exhaust fan are respectively communicated with the outlet of the second dust remover and the inlet of the dry desulfurization, dedusting and denitration integrated machine.
6. The denitration device according to claim 5, further comprising a second induced draft fan;
and the inlet of the second induced draft fan and the outlet of the second induced draft fan are respectively communicated with the outlet of the dry desulfurization, dedusting and denitration integrated machine and the inlet of the chimney.
7. The denitration apparatus according to any one of claims 1 to 6, wherein the first denitration agent in the medium-low temperature SCR reactor comprises ammonia water,
and/or
Liquid ammonia is added into the reaction kettle,
and/or
Urea.
8. The denitration device according to any one of claims 1 to 6, wherein a second denitration agent and a denitration absorbent are arranged in the dry desulfurization, dust removal and denitration integrated machine;
the second denitrifier comprises oxidizing gas desulfurization nitrate,
and/or
The oxidized liquid is desulfurized and nitre is removed,
and/or
Oxidized solid desulfurized nitric;
the denitration absorbent is an alkaline absorbent; and/or
The dry desulfurization, dust removal and denitration integrated machine adopts a circulating fluidized bed technology.
9. The denitration apparatus according to any one of claims 1 to 6, wherein an outlet of each of the high temperature wind boxes, the first low temperature wind boxes and the second low temperature wind boxes is provided with an adjusting damper.
10. A denitration method is characterized by comprising the following steps:
dividing flue gas output by a sintering machine into high-temperature flue gas and low-temperature flue gas respectively, wherein the temperature of the high-temperature flue gas is higher than the reaction temperature of the medium-low temperature SCR reactor, and the temperature of the low-temperature flue gas is lower than the reaction temperature of the medium-low temperature SCR reactor;
adjusting the mixing ratio of the low-temperature flue gas and the high-temperature flue gas to enable the temperature of the mixed first mixed flue gas to reach the reaction temperature of the medium-low-temperature SCR reactor, and inputting the first mixed flue gas into the medium-low-temperature SCR reactor to carry out medium-low-temperature SCR denitration;
mixing the first mixed flue gas subjected to denitration by the medium-low temperature SCR reactor with the rest low-temperature flue gas, and feeding the mixed second mixed flue gas into a dry-method desulfurization, dedusting and denitration integrated machine for secondary denitration;
and discharging the gas discharged from the dry desulfurization, dedusting and denitration integrated machine.
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| CN201911337172.7A CN110841442A (en) | 2019-12-23 | 2019-12-23 | Denitration device and method |
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| CN201911337172.7A CN110841442A (en) | 2019-12-23 | 2019-12-23 | Denitration device and method |
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| CN114887484A (en) * | 2022-05-30 | 2022-08-12 | 山东道简环保科技有限公司 | Circulating waste heat coupling type SCR denitration system |
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