CN110075681B - Dry desulfurization and denitrification device and method suitable for cement kiln flue gas - Google Patents
Dry desulfurization and denitrification device and method suitable for cement kiln flue gas Download PDFInfo
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- CN110075681B CN110075681B CN201910506499.6A CN201910506499A CN110075681B CN 110075681 B CN110075681 B CN 110075681B CN 201910506499 A CN201910506499 A CN 201910506499A CN 110075681 B CN110075681 B CN 110075681B
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- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 title claims abstract description 220
- 239000003546 flue gas Substances 0.000 title claims abstract description 220
- 238000006477 desulfuration reaction Methods 0.000 title claims abstract description 142
- 230000023556 desulfurization Effects 0.000 title claims abstract description 142
- 239000004568 cement Substances 0.000 title claims abstract description 74
- 238000000034 method Methods 0.000 title claims description 27
- 239000000428 dust Substances 0.000 claims abstract description 115
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 claims abstract description 63
- 239000007789 gas Substances 0.000 claims abstract description 62
- 239000000463 material Substances 0.000 claims abstract description 51
- 229910052717 sulfur Inorganic materials 0.000 claims abstract description 40
- 239000011593 sulfur Substances 0.000 claims abstract description 40
- 239000002918 waste heat Substances 0.000 claims abstract description 40
- 238000010521 absorption reaction Methods 0.000 claims abstract description 39
- 229910021529 ammonia Inorganic materials 0.000 claims abstract description 31
- 238000005507 spraying Methods 0.000 claims abstract description 27
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 claims abstract description 26
- 235000011114 ammonium hydroxide Nutrition 0.000 claims abstract description 26
- 239000003054 catalyst Substances 0.000 claims abstract description 20
- 238000010438 heat treatment Methods 0.000 claims abstract description 19
- 238000001704 evaporation Methods 0.000 claims abstract description 17
- 230000008020 evaporation Effects 0.000 claims abstract description 16
- 239000004071 soot Substances 0.000 claims abstract description 16
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 16
- 239000007921 spray Substances 0.000 claims abstract description 15
- 239000002250 absorbent Substances 0.000 claims description 35
- 230000002745 absorbent Effects 0.000 claims description 35
- 239000000779 smoke Substances 0.000 claims description 12
- 239000011575 calcium Substances 0.000 claims description 9
- 230000009471 action Effects 0.000 claims description 8
- 238000006243 chemical reaction Methods 0.000 claims description 8
- 238000007599 discharging Methods 0.000 claims description 8
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 claims description 7
- 229910052791 calcium Inorganic materials 0.000 claims description 7
- 239000006227 byproduct Substances 0.000 claims description 5
- 238000004064 recycling Methods 0.000 claims description 4
- 238000001035 drying Methods 0.000 claims 1
- 239000003344 environmental pollutant Substances 0.000 abstract description 10
- 231100000719 pollutant Toxicity 0.000 abstract description 10
- 230000007774 longterm Effects 0.000 abstract description 6
- 238000005299 abrasion Methods 0.000 abstract description 5
- 239000002574 poison Substances 0.000 abstract description 4
- 231100000614 poison Toxicity 0.000 abstract description 4
- 230000008569 process Effects 0.000 description 10
- 238000010586 diagram Methods 0.000 description 6
- 238000005265 energy consumption Methods 0.000 description 6
- 230000007797 corrosion Effects 0.000 description 5
- 238000005260 corrosion Methods 0.000 description 5
- RAHZWNYVWXNFOC-UHFFFAOYSA-N Sulphur dioxide Chemical compound O=S=O RAHZWNYVWXNFOC-UHFFFAOYSA-N 0.000 description 4
- 238000012546 transfer Methods 0.000 description 4
- 238000004140 cleaning Methods 0.000 description 3
- 238000011161 development Methods 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
- 239000003517 fume Substances 0.000 description 3
- 230000004048 modification Effects 0.000 description 3
- 238000012986 modification Methods 0.000 description 3
- MWUXSHHQAYIFBG-UHFFFAOYSA-N nitrogen oxide Inorganic materials O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 description 3
- 231100000572 poisoning Toxicity 0.000 description 3
- 230000000607 poisoning effect Effects 0.000 description 3
- 239000007787 solid Substances 0.000 description 3
- 230000002378 acidificating effect Effects 0.000 description 2
- 238000010531 catalytic reduction reaction Methods 0.000 description 2
- 239000003638 chemical reducing agent Substances 0.000 description 2
- 230000007613 environmental effect Effects 0.000 description 2
- 239000004744 fabric Substances 0.000 description 2
- 238000012423 maintenance Methods 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 230000001988 toxicity Effects 0.000 description 2
- 231100000419 toxicity Toxicity 0.000 description 2
- 230000002411 adverse Effects 0.000 description 1
- HIVLDXAAFGCOFU-UHFFFAOYSA-N ammonium hydrosulfide Chemical compound [NH4+].[SH-] HIVLDXAAFGCOFU-UHFFFAOYSA-N 0.000 description 1
- 239000001284 azanium sulfanide Substances 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000007664 blowing Methods 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 230000009849 deactivation Effects 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 230000003009 desulfurizing effect Effects 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000005684 electric field Effects 0.000 description 1
- 239000003500 flue dust Substances 0.000 description 1
- 230000017525 heat dissipation Effects 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 238000010248 power generation Methods 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 238000010926 purge Methods 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 238000006722 reduction reaction Methods 0.000 description 1
- 238000005245 sintering Methods 0.000 description 1
- 239000002351 wastewater Substances 0.000 description 1
Classifications
-
- 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
- B01D53/48—Sulfur compounds
- B01D53/50—Sulfur oxides
- B01D53/508—Sulfur oxides by treating the gases with solids
-
- 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
-
- 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
- B01D53/81—Solid phase processes
- B01D53/83—Solid phase processes with moving reactants
-
- 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
-
- 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
- B01D53/90—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
- F23J15/02—Arrangements of devices for treating smoke or fumes of purifiers, e.g. for removing noxious material
-
- 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
-
- 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
- B01D2251/40—Alkaline earth metal or magnesium compounds
- B01D2251/404—Alkaline earth metal or magnesium compounds of calcium
-
- 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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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Environmental & Geological Engineering (AREA)
- General Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Health & Medical Sciences (AREA)
- Biomedical Technology (AREA)
- Analytical Chemistry (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Treating Waste Gases (AREA)
Abstract
A dry desulfurization and denitrification device suitable for cement kiln flue gas, comprising: the device comprises a cement kiln, a preheater, a waste heat boiler, a desulfurization absorption tower provided with a water spray gun, a dust remover and an SCR medium-low temperature denitration device provided with a rectifying device and a soot blower which are connected in sequence; the dust removing material outlet of the dust remover is communicated with the dust removing material circulating inlet through an air chute, and the low-sulfur low-dust flue gas outlet is connected with the first flue gas pipeline; the pipeline is provided with a denitration inlet windshield, a flue gas circulation inlet II, a heating device and an ammonia spraying device; the purified gas outlet is connected with a second flue gas pipeline; the pipeline is sequentially provided with an ammonia water evaporation wind outlet, an induced draft fan and a purified gas circulation outlet which are communicated with a feed inlet of the ammonia spraying device; the purified gas circulation outlet is respectively communicated with the flue gas circulation inlet I and the flue gas circulation inlet II. The device can efficiently desulfurize, dedusting and denitrate, reduce the poison of pollutants to the catalyst, reduce the system blockage and abrasion, and ensure the long-term stable operation of the whole device.
Description
Technical Field
The invention relates to the technical field of desulfurization and denitrification treatment, in particular to a dry desulfurization and denitrification device and method suitable for cement kiln flue gas.
Background
In recent years, the state is greatly pushing the flue gas ultra-low emission modification in the non-electric field, the ultra-low emission modification of the flue gas of the cement kiln has been proposed, and the emission concentrations of the flue gas particulate matters, sulfur dioxide and nitrogen oxides of the cement kiln in the policy documents such as local standards of a plurality of provinces and a bench, an atmospheric pollution control working scheme and the like are required to be not higher than 10mg/m 3、50mg/m3 and 150 (or 100) mg/m 3 respectively. Meanwhile, as environmental protection emission standards become more and more stringent, the national pollution control force is continuously increased, and the smoke emission standards of the cement kiln are revised. Since the beginning of the year 7, month 1 of 2015, the current enterprises start to strictly execute GB4915-2013 emission Standard for atmospheric pollutants for Cement industry, requiring that the NO x emission limits of existing and newly built cement enterprises be reduced from the original 800mg/Nm 3 to 400mg/Nm 3 (the emission limit of NO x in the key region is 320mg/Nm 3). Therefore, the addition of a desulfurization and denitrification device to the cement kiln flue gas is imperative.
At present, the purification routes for carrying out desulfurization and denitrification treatment on the cement kiln flue gas are many, most cement enterprises adopt the traditional wet desulfurization in the aspect of desulfurization, but the wet desulfurization corrosion is serious, and the problems of desulfurization waste water, white removal and the like are needed to be added at the rear end; however, most cement enterprises in denitration adopt a selective non-catalytic reduction method (SNCR denitration technology), but the denitration efficiency of SNCR is about 60%, and the existing emission requirements cannot be met. With the development of industry and the improvement of environmental protection requirements, the adoption of dry desulfurization and Selective Catalytic Reduction (SCR) denitration becomes the development direction of treating cement kiln flue gas for those skilled in the art.
The Chinese patent with application publication number CN109364741A discloses a cement kiln flue gas dry desulfurization and high-dust SCR denitration device and a technology, wherein the technology process comprises the following steps: the flue gas to be purified firstly enters an SCR device, is subjected to high-temperature SCR denitration (about 350 ℃), and is discharged into a chimney through a draught fan after dry desulfurization and bag dust removal. However, the above technical solution has the following disadvantages: (1) Catalyst poisoning and blockage problems and low denitration efficiency; because the flue gas directly advances SCR device in this technical scheme earlier, belongs to high dirt and arranges, and flue gas temperature is high, and dust, caO content are high, easily lead to catalyst poisoning deactivation and jam, and life is short, still easily causes the emergence of the high scheduling problem of operation and maintenance cost of denitrification facility. (2) downstream equipment plugging corrosion problems; because facilities such as waste heat power generation boiler are arranged to the SCR denitrification facility low reaches of arranging here, if the ammonia escape control of SCR denitrification system is improper, easily causes waste heat boiler's jam, corruption and thermal efficiency and reduce the adverse problem.
The Chinese patent with the issued publication number of CN204619708U discloses a flue gas combined denitration device of a cement rotary kiln, which comprises the following process flows: firstly, reducing agents such as ammonia water are sprayed into a decomposing furnace 2, the flue gas which needs to be further purified firstly enters a waste heat boiler, then enters an SCR device after being subjected to bag dust removal, and finally enters a chimney after being subjected to high-temperature SCR denitration (180-220 ℃), and then is discharged into the chimney through a draught fan. However, the above technical solution has the following disadvantages: (1) Risks such as catalyst poisoning, blockage, low denitration efficiency and the like exist; although the technical scheme is used for dedusting, SO 2 is not effectively removed, the catalyst is easy to poison, inactivate and block, the service life is short, and the problems of high operation and maintenance cost of the denitration device are easy to occur. (2) downstream equipment plugging corrosion problems; because ammonia water is sprayed into the decomposing furnace to carry out SNCR reaction, if ammonia escape is improperly controlled, the problems of blockage, corrosion, heat efficiency reduction and the like of the waste heat boiler are easily caused. (3) The technical scheme can not meet the operational condition of SO 2、NOx at the cement line start-up stage.
In conclusion, in order to meet the increasingly strict ultra-low emission requirements of the cement industry, the development of a desulfurization and denitrification integrated device which has low consumption and can stably run for a long time has very important significance.
Disclosure of Invention
In view of the above, the invention aims to provide a dry desulfurization and denitrification device and method suitable for cement kiln flue gas, which can reduce the toxicity of pollutants such as dust, caO, SO 2 and the like to a catalyst, reduce the system blockage and abrasion, ensure the long-term stable operation of the whole device, and simultaneously ensure the desulfurization and denitrification under all working conditions.
The invention provides a dry desulfurization and denitrification device suitable for cement kiln flue gas, which comprises:
The cement kiln, the preheater and the waste heat boiler are connected in sequence;
The inlet flue is connected with a discharge hole of the waste heat boiler; the inlet flue is sequentially provided with a smoke circulation inlet I, a dedusting material circulation inlet and an absorbent inlet; the desulfurization absorption tower is provided with a water spray gun;
A dust remover with a feeding hole connected with a discharging hole of the desulfurization absorption tower; the dedusting material outlet of the deduster is communicated with the dedusting material circulating inlet through an air chute, and the low-sulfur low-dust flue gas outlet is connected with a first flue gas pipeline;
The feed inlet is connected with the low-sulfur low-dust flue gas outlet of the dust remover through the first flue gas pipeline; the first flue gas pipeline is sequentially provided with a denitration inlet windshield, a flue gas circulation inlet II, a heating device and an ammonia spraying device; the top of the SCR denitration device is provided with a rectifying device, the side part of the SCR denitration device is provided with a soot blower, and a bottom purified gas outlet is connected with a second flue gas pipeline;
A chimney connected with a purified gas outlet of the SCR denitration device through the second flue gas pipeline; the second flue gas pipeline is sequentially provided with an ammonia water evaporation wind outlet, an induced draft fan and a purified gas circulation outlet; the ammonia water evaporation wind outlet is communicated with a feed inlet of the ammonia spraying device;
the purified gas circulation outlet is respectively communicated with the flue gas circulation inlet I and the flue gas circulation inlet II.
Preferably, the dedusting material outlet is also connected with a desulfurization byproduct outer discharge port.
Preferably, the flue gas circulation inlet is respectively communicated with the flue gas circulation inlet II and the purified gas circulation outlet through a third flue gas pipeline; the third flue gas pipeline is provided with a recirculation windshield.
Preferably, the flue gas circulation inlet II is communicated with the third flue gas pipeline through a fourth flue gas pipeline; and the fourth flue gas pipeline is provided with a desulfurization recycle windshield.
Preferably, the SCR denitration device is matched with a medium-low temperature catalyst, and the temperature of a reaction window is 70-280 ℃.
Preferably, the method further comprises:
GGH heat exchanger on first flue gas pipeline and second flue gas pipeline.
The invention also provides a dry desulfurization and denitrification method suitable for the cement kiln flue gas, which adopts the dry desulfurization and denitrification device adopting the technical scheme, and comprises the following steps:
a) Preheating cement kiln flue gas, performing dry desulfurization under the action of an absorbent, and then removing dust to obtain dust removing materials and low-sulfur low-dust flue gas respectively; wherein the dedusting material is subjected to the dry desulfurization in a circulating way;
b) And (c) SCR denitration is carried out on the low-sulfur low-dust flue gas obtained in the step a) under the conditions of 70-280 ℃ and ammonia water to obtain purified gas.
Preferably, the absorbent in step a) is a calcium-based alkaline absorbent; the absorbent is added according to the addition amount of the calcium-based alkaline absorbent.
Preferably, the outlet temperature of the dry desulfurization in step a) is from 70 ℃ to 110 ℃.
Preferably, the purified gas obtained in step b) can be used for circulation to assist the preheating of the dry desulfurization and denitration device.
Preferably, the method further comprises:
and c), exchanging heat between the low-sulfur and low-dust flue gas obtained in the step a) and the purified gas obtained in the step b), and then performing SCR denitration.
The invention provides a dry desulfurization and denitrification device suitable for cement kiln flue gas, which comprises: the cement kiln, the preheater and the waste heat boiler are connected in sequence; the inlet flue is connected with a discharge hole of the waste heat boiler; the inlet flue is sequentially provided with a smoke circulation inlet I, a dedusting material circulation inlet and an absorbent inlet; the desulfurization absorption tower is provided with a water spray gun; a dust remover with a feeding hole connected with a discharging hole of the desulfurization absorption tower; the dedusting material outlet of the deduster is communicated with the dedusting material circulating inlet through an air chute, and the low-sulfur low-dust flue gas outlet is connected with a first flue gas pipeline; the feed inlet is connected with the low-sulfur low-dust flue gas outlet of the dust remover through the first flue gas pipeline; the first flue gas pipeline is sequentially provided with a denitration inlet windshield, a flue gas circulation inlet II, a heating device and an ammonia spraying device; the top of the SCR denitration device is provided with a rectifying device, the side part of the SCR denitration device is provided with a soot blower, and a bottom purified gas outlet is connected with a second flue gas pipeline; a chimney connected with a purified gas outlet of the SCR denitration device through the second flue gas pipeline; the second flue gas pipeline is sequentially provided with an ammonia water evaporation wind outlet, an induced draft fan and a purified gas circulation outlet; the ammonia water evaporation wind outlet is communicated with a feed inlet of the ammonia spraying device; the purified gas circulation outlet is respectively communicated with the flue gas circulation inlet I and the flue gas circulation inlet II. Compared with the prior art, the dry desulfurization and denitrification device provided by the invention is suitable for cement kiln flue gas, can reduce the poison of pollutants such as dust, caO, SO 2 and the like to a catalyst while high-efficiency desulfurization, dust removal and denitrification are realized, reduce system blockage and abrasion, ensure long-term stable operation of an SCR device, and simultaneously ensure desulfurization and denitrification under all working conditions. Experimental results show that the desulfurization efficiency of the dry desulfurization and denitrification device provided by the invention can reach more than 99%, the denitrification efficiency can reach more than 95%, the emission concentration of SO 2、NOx is respectively lower than 10mg/Nm 3、50mg/Nm3, and the ultra-low emission is realized; and the dust concentration is lower than 5mg/Nm 3.
In addition, the dry desulfurization and denitrification device provided by the invention can be selectively matched with the GGH flue gas heat exchanger, so that the heating energy consumption is saved, and the dry desulfurization and denitrification device has a wide application prospect.
Drawings
Fig. 1 is a schematic structural diagram of a dry desulfurization and denitrification device suitable for cement kiln flue gas, which is provided by the embodiment of the invention;
Fig. 2 is a schematic structural diagram of a dry desulfurization and denitrification device for cement kiln flue gas provided in embodiment 1 of the present invention;
Fig. 3 is a schematic structural diagram of a dry desulfurization and denitrification device for cement kiln flue gas provided in embodiment 2 of the present invention.
Detailed Description
The technical solutions of the present invention will be clearly and completely described in conjunction with the embodiments of the present invention, and it is apparent that the described embodiments are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
The invention provides a dry desulfurization and denitrification device suitable for cement kiln flue gas, which comprises:
The cement kiln, the preheater and the waste heat boiler are connected in sequence;
The inlet flue is connected with a discharge hole of the waste heat boiler; the inlet flue is sequentially provided with a smoke circulation inlet I, a dedusting material circulation inlet and an absorbent inlet; the desulfurization absorption tower is provided with a water spray gun;
A dust remover with a feeding hole connected with a discharging hole of the desulfurization absorption tower; the dedusting material outlet of the deduster is communicated with the dedusting material circulating inlet through an air chute, and the low-sulfur low-dust flue gas outlet is connected with a first flue gas pipeline;
The feed inlet is connected with the low-sulfur low-dust flue gas outlet of the dust remover through the first flue gas pipeline; the first flue gas pipeline is sequentially provided with a denitration inlet windshield, a flue gas circulation inlet II, a heating device and an ammonia spraying device; the top of the SCR denitration device is provided with a rectifying device, the side part of the SCR denitration device is provided with a soot blower, and a bottom purified gas outlet is connected with a second flue gas pipeline;
A chimney connected with a purified gas outlet of the SCR denitration device through the second flue gas pipeline; the second flue gas pipeline is sequentially provided with an ammonia water evaporation wind outlet, an induced draft fan and a purified gas circulation outlet; the ammonia water evaporation wind outlet is communicated with a feed inlet of the ammonia spraying device;
The purified gas circulation outlet is respectively communicated with the flue gas circulation inlet I and the flue gas circulation inlet II.
Referring to fig. 1, fig. 1 is a schematic structural diagram of a dry desulfurization and denitrification device for flue gas in a cement kiln according to embodiment 1 of the present invention; the device comprises a cement kiln, a preheater, a waste heat boiler, an inlet flue, a discharge port of the waste heat boiler, a desulfurization absorption tower, a flue gas circulation inlet I, a dedusting material circulation inlet, an absorbent inlet, a water spray gun, a feeding port of a dust remover, a discharge port of the desulfurization absorption tower, a dust remover, a dedusting material outlet, an air chute, a low-sulfur low-dust flue gas outlet, a first flue gas pipeline, a feed port of an SCR denitration device, a rectifier device, a denitration inlet windshield, a flue gas circulation inlet II, a heating device, an ammonia spraying device, a rectifier device, an ammonia spraying device, an induced draft fan, an ammonia water evaporation air outlet, an induced draft fan, a purified gas circulation outlet and an ammonia spraying device, wherein the cement kiln is 1, the preheater is 2, the waste heat boiler, the inlet flue gas is 4, the inlet flue gas flue, the discharge port of the waste heat boiler is 5, the desulfurization absorption tower is 6, the desulfurization absorption tower is 7, the flue gas circulation inlet I, the dedusting material circulation inlet is 8, the absorbent inlet is 9, the water spray gun is 10, the feeding port of the dust remover, the dust-absorbing device is 11, the inlet of the dust-absorbing device is 12, the air circulation inlet of the air, the low-sulfur low-dust circulation inlet is 17, the flue gas circulation inlet of the exhaust gas, the ammonia gas, the exhaust gas is 31, the exhaust gas circulation inlet of the ammonia.
In the invention, the dry desulfurization and denitrification device comprises a cement kiln (1), a preheater (2), a waste heat boiler (3), a desulfurization absorption tower (6), a dust remover (13), an SCR denitrification device (19) and a chimney (28). In the invention, the cement kiln (1), the preheater (2) and the waste heat boiler (3) are connected in sequence; the cement kiln flue gas can enter the waste heat boiler (3) after being preheated by the preheater (2) from the cement kiln (1), and the heat in the cement kiln flue gas is recovered in the waste heat boiler (3) as much as possible. In the invention, the waste heat boiler (3) is provided with a discharge port (5).
In the invention, the waste heat boiler (3) is arranged in front of the desulfurization absorption tower (6), so that the waste heat recovery efficiency in the flue gas can be ensured as much as possible, and the problems of blockage, corrosion and the like caused by ammonia spraying and ammonium bisulfide formation are avoided when the SCR denitration device (19) is arranged in front of the waste heat boiler (3).
In the invention, the desulfurization absorption tower (6) is used for desulfurizing the flue gas; the bottom of the desulfurization absorption tower (6) is provided with an inlet flue (4), the top of the desulfurization absorption tower is provided with a discharge hole (12), and the lower part of the desulfurization absorption tower is provided with a water spray gun (10) close to the inlet flue (4). In the invention, the inlet flue (4) is connected with the discharge port (5) of the waste heat boiler (3), so that the flue gas in the waste heat boiler (3) can enter the desulfurization absorption tower (6) through the inlet flue (4).
In the invention, the inlet flue (4) is sequentially provided with a flue gas circulation inlet I (7), a dedusting material circulation inlet (8) and an absorbent inlet (9); the absorbent inlet (9) is connected with the absorbent bin and is used for leading the absorbent in the absorbent bin into the inlet flue (4). In the invention, the absorbent is preferably a calcium-based alkaline absorbent, and can be quickly reacted with and removed from pollutants such as SO 2、SO3、HCl、NO2 in the flue gas entering the desulfurization absorption tower (6). The invention adopts dry desulfurization, and the gas-solid two phases in the desulfurization absorption tower (6) generate violent turbulence and mixing due to the action of air flow, so as to fully contact, greatly strengthen mass transfer and heat transfer between the gas and the solid, and ensure the full absorption and removal of the acidic substances.
In the invention, the water spray gun (10) is used for controlling the temperature of the discharge port (12) of the desulfurization absorption tower (6) to be 70-110 ℃, so that the high-efficiency desulfurization is ensured, the damage of the high-temperature flue gas to the rear end cloth bag is avoided, and the stable temperature of the subsequent denitration inlet is convenient for the long-term stable operation of the denitration device.
In the invention, the dust remover (13) is used for removing dust from the desulfurized flue gas, collecting the flue dust and unreacted materials, and obtaining low-sulfur and low-dust flue gas; the dust remover (13) is preferably a cloth bag dust remover. In the invention, the dust remover (13) is provided with a feed inlet (11), a dust removing material outlet (14) and a low-sulfur low-dust flue gas outlet (16); the feeding port (11) is connected with the discharging port (12) of the desulfurization absorption tower (6) and is used for introducing desulfurized flue gas into the dust remover (13).
In the invention, the dust remover (13) is arranged in front of the SCR denitration device (19), SO that the concentration of dust, caO and SO 2 in the flue gas can be greatly reduced, the effect that other pollutants except NO x in the flue gas enter the SCR denitration device (19) are ultra-clean is realized, the damage of the pollutants to the catalyst can be greatly reduced, and the service life of the catalyst is prolonged.
In the invention, the dedusting material outlet (14) is communicated with the dedusting material circulation inlet (8) through the air chute (15) and is used for circulating dedusting material to the inlet flue (4) and then entering the desulfurization absorption tower (6) for desulfurization. In the invention, the dedusting material outlet (14) is preferably also connected with a desulfurization byproduct discharge port for discharging part of dedusting material.
In the invention, the low-sulfur low-dust flue gas outlet (16) is connected with a first flue gas pipeline (17).
In the invention, the SCR denitration device (19) is used for SCR denitration to obtain purified gas. In the invention, the SCR denitration device (19) is provided with a feed inlet (18) and a purified gas outlet (26), the top is provided with a rectifying device (24), and the side part is provided with a soot blower (25); wherein the feed inlet (18) is connected with a low-sulfur low-dust flue gas outlet (16) of the dust remover (13) through the first flue gas pipeline (17); the sootblowers (25) are preferably sonic/steam sootblowers. In the invention, the first flue gas pipeline (17) is sequentially provided with a denitration inlet windshield (20), a flue gas circulation inlet II (21), a heating device (22) and an ammonia spraying device (23); the heating device (22) is used for controlling the temperature of the low-sulfur low-dust flue gas; the ammonia spraying device (23) is used for spraying ammonia water into the SCR denitration device (19) after gasifying the ammonia water.
In the invention, the purified gas outlet (26) is arranged at the bottom of the SCR denitration device (19) and is connected with the second flue gas pipeline (27).
In the invention, the rectifying device (24) can ensure more stable operation of the SCR denitration device (19); the soot blower (25) is used for periodically carrying out soot cleaning treatment on the catalyst to prevent soot deposition.
In the invention, the chimney (28) is used for discharging purified gas; the chimney (28) is connected with a purified gas outlet (26) of the SCR denitration device (19) through the second flue gas pipeline (27). In the invention, the second flue gas pipeline (27) is sequentially provided with an ammonia evaporation wind outlet (29), an induced draft fan (30) and a purified gas circulation outlet (31); wherein the ammonia water evaporation wind outlet (29) is communicated with a feed inlet (32) of the ammonia spraying device (23) and is used for realizing ammonia evaporation.
In the invention, the induced draft fan (30) is used for providing power for flue gas. In the invention, the flue gas circulation inlet I (7) is respectively communicated with the flue gas circulation inlet II (21) and the purified gas circulation outlet (31); preferably, the flue gas circulation inlet I (7) is respectively communicated with the flue gas circulation inlet II (21) and the purified gas circulation outlet (31) through a third flue gas pipeline. In the present invention, the third flue gas duct is preferably provided with a recirculation damper. In the invention, the flue gas circulation inlet II (21) is preferably communicated with the third flue gas pipeline through a fourth flue gas pipeline; the fourth flue gas pipeline is preferably provided with a desulfurization recycle windshield. Under the action of the induced draft fan (30) (for example, by utilizing the pressure difference between two ends), the opening degree of the baffle plate of the recirculation windshield and the toward desulfurization recirculation windshield can be adjusted according to the change condition of the front-end load smoke quantity, so that the stability of the system under different load working conditions is ensured.
In addition, the connection of the third flue gas pipeline and the fourth flue gas pipeline can also realize that the purified gas circulation outlet (31) is connected with the flue gas circulation inlet II (21) through the fourth flue gas pipeline, thereby being beneficial to more rapid preheating SCR denitration device and comprising the following specific processes:
Before starting the machine, firstly closing a denitration inlet windshield (20) and a recirculation windshield, starting a desulfurization and recirculation windshield, then starting a draught fan (30), starting a heating device (22), enabling recirculated hot flue gas not to pass through a desulfurization absorption tower (6) and a dust remover (13) for cooling, more rapidly preheating an SCR denitration device (19), starting a desulfurization and recirculation windshield (17) before starting the machine by sintering, closing or reducing the denitration inlet windshield (20), and carrying out desulfurization and bed building in advance to meet the time required by bed building, thereby meeting the desulfurization and denitration operation under the working condition of starting the machine and the low-load working condition; on the one hand, when the SCR denitration device (19) is preheated, the heat dissipation loss of the recirculated hot flue gas is smaller, the recirculated flue gas can be preheated more quickly, on the other hand, during the preheating period, the recirculated flue gas does not pass through the desulfurization absorption tower (6) and the dust remover (13), the resistance is smaller, and the energy consumption during denitration preheating can be saved.
In the invention, the dry desulfurization and denitrification device further comprises:
GGH heat exchangers arranged on the first flue gas pipeline (17) and the second flue gas pipeline (27); the low-sulfur low-dust flue gas (low-temperature gas) exhausted by the low-sulfur low-dust flue gas outlet (16) of the dust remover (13) exchanges heat with the purified gas (high-temperature gas) exhausted by the purified gas outlet (26) of the SCR denitration device (19), so that the heating energy consumption is saved, and whether the GGH heat exchanger is matched or not can be determined according to the temperature of a reaction window of the selected catalyst.
The dry desulfurization and denitrification device provided by the invention is suitable for cement kiln flue gas, can reduce the toxicity of pollutants such as dust, caO, SO 2 and the like to a catalyst while high-efficiency desulfurization, dust removal and denitrification are realized, reduces system blockage and abrasion, ensures long-term stable operation of the SCR device, and simultaneously ensures desulfurization and denitrification under all working conditions. Experimental results show that the desulfurization efficiency of the dry desulfurization and denitrification device provided by the invention can reach more than 99%, the denitrification efficiency can reach more than 95%, the emission concentration of SO 2、NOx is respectively lower than 10mg/Nm 3、50mg/Nm3, and the ultra-low emission is realized; and the dust concentration is lower than 5mg/Nm 3.
In addition, the dry desulfurization and denitrification device provided by the invention can be matched with the GGH flue gas heat exchanger, so that the heating energy consumption is saved, and the dry desulfurization and denitrification device has a wide application prospect.
The invention also provides a dry desulfurization and denitrification method suitable for the cement kiln flue gas, which adopts the dry desulfurization and denitrification device adopting the technical scheme, and comprises the following steps:
a) Preheating cement kiln flue gas, performing dry desulfurization under the action of an absorbent, and then removing dust to obtain dust removing materials and low-sulfur low-dust flue gas respectively; wherein the dedusting material is subjected to the dry desulfurization in a circulating way;
b) And (c) SCR denitration is carried out on the low-sulfur low-dust flue gas obtained in the step a) under the conditions of 70-280 ℃ and ammonia water to obtain purified gas.
Firstly preheating cement kiln flue gas, carrying out dry desulfurization under the action of an absorbent, and then removing dust to obtain dust removal materials and low-sulfur low-dust flue gas respectively. The source of the cement kiln flue gas is not particularly limited, and the cement kiln flue gas well known to those skilled in the art can be used. In a preferred embodiment of the invention, the concentration of NO x in the cement kiln flue gas is preferably 100mg/Nm 3～2000mg/Nm3, more preferably 400mg/Nm 3～1500mg/Nm3; the concentration of SO 2 in the cement kiln flue gas is preferably 100mg/Nm 3～1500mg/Nm3, more preferably 400mg/Nm 3～1000mg/Nm3.
In the invention, the preheating process is carried out in a preheater (2) connected with the cement kiln (1), and the heat in the flue gas of the cement kiln is recovered as much as possible in a waste heat boiler (3). In the present invention, the absorbent is preferably a calcium-based alkaline absorbent, more preferably Ca (OH) 2; the absorbent can be quickly reacted with pollutants such as SO 2、SO3、HCl、NO2 and the like in the flue gas of the cement kiln to remove. The source of the calcium-based alkaline absorbent is not particularly limited in the present invention, and commercially available products known to those skilled in the art may be used. In the invention, the absorbent is preferably added according to a calcium-based alkaline absorbent, and the sufficient absorption and removal of the acidic substances are ensured by utilizing the mass transfer and heat transfer between the extremely large gas and solid.
In the invention, the dry desulfurization process is carried out in a desulfurization absorption tower (6), and the water spray gun (10) is used for spraying water to control the reaction temperature. In the present invention, the outlet temperature of the dry desulfurization is preferably 70 to 110 ℃.
In the invention, the dust removal process is carried out in a dust remover (13) to respectively obtain dust removal materials and low-sulfur low-dust flue gas; wherein the dust removal material is circularly subjected to the dry desulfurization.
After the low-sulfur low-dust flue gas is obtained, the obtained low-sulfur low-dust flue gas is subjected to SCR denitration under the conditions of 70-280 ℃ and ammonia water to obtain purified gas. In the invention, the SCR denitration process is performed in an SCR denitration device (19). The invention performs medium-low temperature SCR denitration at the temperature, and has stable operation and high denitration efficiency.
In the present invention, part of the purge gas obtained in step b) is preferably recycled back to the absorption tower (6) assisting dry desulfurization and the SCR denitration device (19) assisting dry desulfurization and preheating.
In the present invention, the dry desulfurization and denitrification method preferably further comprises:
And c), exchanging heat between the low-sulfur and low-dust flue gas obtained in the step a) and the purified gas obtained in the step b), and then performing SCR denitration. In the invention, the heat exchange process is preferably performed in a GGH heat exchanger; thereby saving heating energy consumption, and particularly determining whether to configure according to the reaction window temperature of the selected catalyst.
The invention provides a dry desulfurization and denitrification device suitable for cement kiln flue gas, which comprises: the cement kiln, the preheater and the waste heat boiler are connected in sequence; the inlet flue is connected with a discharge hole of the waste heat boiler; the inlet flue is sequentially provided with a smoke circulation inlet I, a dedusting material circulation inlet and an absorbent inlet; the desulfurization absorption tower is provided with a water spray gun; a dust remover with a feeding hole connected with a discharging hole of the desulfurization absorption tower; the dedusting material outlet of the deduster is communicated with the dedusting material circulating inlet through an air chute, and the low-sulfur low-dust flue gas outlet is connected with a first flue gas pipeline; the feed inlet is connected with the low-sulfur low-dust flue gas outlet of the dust remover through the first flue gas pipeline; the first flue gas pipeline is sequentially provided with a denitration inlet windshield, a flue gas circulation inlet II, a heating device and an ammonia spraying device; the top of the SCR denitration device is provided with a rectifying device, the side part of the SCR denitration device is provided with a soot blower, and a bottom purified gas outlet is connected with a second flue gas pipeline; a chimney connected with a purified gas outlet of the SCR denitration device through the second flue gas pipeline; the second flue gas pipeline is sequentially provided with an ammonia water evaporation wind outlet, an induced draft fan and a purified gas circulation outlet; the ammonia water evaporation wind outlet is communicated with a feed inlet of the ammonia spraying device; and the smoke circulation inlet I is respectively communicated with the smoke circulation inlet II and the purified gas circulation outlet. Compared with the prior art, the dry desulfurization and denitrification device provided by the invention is suitable for cement kiln flue gas, can reduce the poison of pollutants such as dust, caO, SO 2 and the like to a catalyst while high-efficiency desulfurization, dust removal and denitrification are realized, reduce system blockage and abrasion, ensure long-term stable operation of the whole device, and simultaneously ensure desulfurization and denitrification under all working conditions. Experimental results show that the desulfurization efficiency of the dry desulfurization and denitrification device provided by the invention can reach more than 99%, the denitrification efficiency can reach more than 95%, the emission concentration of SO 2、NOx is respectively lower than 10mg/Nm 3、50mg/Nm3, and the ultra-low emission is realized; and the dust concentration is lower than 5mg/Nm 3.
In addition, the dry desulfurization and denitrification device provided by the invention can be matched with the GGH flue gas heat exchanger, so that the heating energy consumption is saved, and the dry desulfurization and denitrification device has a wide application prospect.
In order to further illustrate the present invention, the following examples are provided. The cement kiln fumes used in the following examples of the present invention were derived from a cement kiln of 5000t/d, the fume amount was 38000 Nm 3/h (standard condition), the concentration of NO x in the cement kiln fumes was 400mg/Nm 3～1500mg/Nm3,SO2 and the concentration was 400mg/Nm 3～1000mg/Nm3. ; the absorbent used is Ca (OH) 2, and the denitration reducing agent used is ammonia water.
Example 1
The schematic structural diagram of the dry desulfurization and denitrification device suitable for cement kiln flue gas provided in embodiment 1 is shown in fig. 2; wherein 1 is a cement kiln, 2 is a preheater, 3 is a waste heat boiler, 4 is a discharge port of the waste heat boiler, 6 is a desulfurization absorption tower, 7 is a flue gas circulation inlet I,8 is a dedusting material circulation inlet, 9 is an absorbent inlet, 10 is a water spray gun, 11 is a feed port of a dust remover, 12 is a discharge port of the desulfurization absorption tower, 13 is the dust remover, 14 is a dedusting material outlet, 15 is an air chute, 16 is a low-sulfur low-dust flue gas outlet, 17 is a first flue gas pipeline, 18 is a feed port of an SCR denitration device, 19 is the SCR denitration device, 20 is a denitration inlet windshield, 21a flue gas circulation inlet II,22 is a heating device, 23 is an ammonia spraying device, 24 is a rectifying device, 25 is a soot blower, 26 is a purified gas outlet, 27 is a second flue gas pipeline, 28 is a chimney, 29 is an ammonia evaporation wind outlet, 30 is an induced draft fan, 31 is a purified gas circulation outlet, 32 is a feed inlet of the ammonia spraying device, 33 is a desulfurization byproduct external discharge port, 34 is a third flue gas pipeline, 35 is a recirculation windshield, 36 is a fourth flue gas pipeline, and 37 is a toward desulfurization recirculation windshield.
The cement kiln flue gas desulfurization, dust removal and denitration are carried out by adopting the dry desulfurization and denitration device, and the concrete working process is as follows:
The method comprises the steps of (1) preheating cement kiln flue gas from a cement kiln (1) through a preheater (2) and then entering a waste heat boiler (3), recovering heat in the cement kiln flue gas as much as possible in the waste heat boiler (3), then entering a desulfurization absorption tower (6) through a discharge port (5) of the waste heat boiler (3) through an inlet flue (4), carrying out dry desulfurization under the action of an absorbent, controlling the temperature through a water spray gun (10) to enable the outlet temperature of the desulfurized flue gas to be 70-110 ℃, and then entering a dust remover (13) through a feed inlet (11) of the dust remover (13) to remove dust to obtain dust removal materials and low-sulfur and low-dust flue gas respectively; wherein the dedusting materials enter the inlet flue (4) from the dedusting material circulating inlet (8) through the dedusting material outlet (14) and enter the inlet flue (4) through the air chute (15), and the dry desulfurization is performed in a recycling way.
(2) The low-sulfur low-dust flue gas obtained in the step (1) is controlled to be 70-150 ℃ through a heating device (22), enters an SCR denitration device (19), the SCR denitration device (19) adopts a low-temperature catalyst (a reaction window is 70-150 ℃) to perform SCR denitration in the presence of ammonia water, the ammonia water is evaporated and diluted through an ammonia spraying device (23) and then sprayed into the SCR denitration device (19) to obtain purified gas, and finally is discharged into a chimney (28) through a draught fan (30);
in addition, in order to prevent dust deposit, the SCR denitration device (19) is matched with a soot blower (25), and the catalyst is subjected to soot cleaning treatment regularly.
Example 2
The schematic structural diagram of the dry desulfurization and denitrification device suitable for cement kiln flue gas provided in embodiment 2 is shown in fig. 3; wherein 1 is a cement kiln, 2 is a preheater, 3 is a waste heat boiler, 4 is a discharge port of the waste heat boiler, 6 is a desulfurization absorption tower, 7 is a flue gas circulation inlet I,8 is a dedusting material circulation inlet, 9 is an absorbent inlet, 10 is a water spray gun, 11 is a feed port of a dust remover, 12 is a discharge port of the desulfurization absorption tower, 13 is a dust remover, 14 is a dedusting material outlet, 15 is an air chute, 16 is a low-sulfur low-dust flue gas outlet, 17 is a first flue gas pipeline, 18 is a feed port of an SCR denitration device, 19 is the SCR denitration device, 20 is a denitration inlet windshield, 21 is a flue gas circulation inlet II,22 is a heating device, 23 is an ammonia spraying device, 24 is a rectifying device, 25 is a soot blowing device, 26 is a purified gas outlet, 27 is a second flue gas pipeline, 28 is a chimney, 29 is an evaporating wind outlet, 30 is a draught fan, 31 is a purified gas circulation outlet, 32 is a feed port of the ammonia spraying device, 33 is an outer byproduct discharge port, 34 is a third flue gas pipeline, 35 is a recycling windshield, 36 is a fourth flue gas windshield, 37 is a heat exchanging device, and 37 is a heat exchanging device.
The cement kiln flue gas desulfurization, dust removal and denitration are carried out by adopting the dry desulfurization and denitration device, and the concrete working process is as follows:
The method comprises the steps of (1) preheating cement kiln flue gas from a cement kiln (1) through a preheater (2) and then entering a waste heat boiler (3), recovering heat in the cement kiln flue gas as much as possible in the waste heat boiler (3), then entering a desulfurization absorption tower (6) through a discharge port (5) of the waste heat boiler (3) through an inlet flue (4), carrying out dry desulfurization under the action of an absorbent, controlling the temperature through a water spray gun (10) to enable the outlet temperature of the desulfurized flue gas to be 90-100 ℃, and then entering a dust remover (13) through a feed inlet (11) of the dust remover (13) to remove dust to obtain dust removal materials and low-sulfur and low-dust flue gas respectively; wherein the dedusting materials enter the inlet flue (4) from the dedusting material circulating inlet (8) through the dedusting material outlet (14) and enter the inlet flue (4) through the air chute (15), and the dry desulfurization is performed in a recycling way.
(2) After the low-sulfur low-dust flue gas obtained in the step (1) is subjected to heat exchange through a GGH heat exchanger (38), the temperature is increased to 250 ℃, the temperature is controlled to be 250-280 ℃ through a heating device (22), the flue gas enters an SCR denitration device (19), the SCR denitration device (19) adopts a medium-temperature catalyst (reaction window 230-280 ℃) to perform SCR denitration in the presence of ammonia water, the ammonia water is evaporated and diluted through an ammonia spraying device (23) and then sprayed into the SCR denitration device (19), so as to obtain purified gas, the temperature is reduced to 120 ℃ after the heat exchange between the GGH heat exchanger (38) and the low-sulfur low-dust flue gas, and finally the purified gas is discharged into a chimney (28) through a draught fan (30);
in addition, in order to prevent dust deposit, the SCR denitration device (19) is matched with a soot blower (25), and the catalyst is subjected to soot cleaning treatment regularly.
According to detection, the desulfurization efficiency of the dry desulfurization and denitrification device provided by the embodiment 1 and the embodiment 2 of the invention can reach more than 99%, and the denitrification efficiency can reach more than 95%; after the dry desulfurization and denitrification device is adopted to carry out desulfurization, dust removal and denitrification on the cement kiln flue gas, the emission concentration of SO 2、NOx in the obtained purified gas is respectively lower than 10mg/Nm 3、50mg/Nm3, SO that ultra-low emission is realized; and the dust concentration is lower than 5mg/Nm 3.
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 novel features disclosed herein.
Claims (9)
1. The utility model provides a dry process SOx/NOx control device suitable for cement kiln flue gas which characterized in that includes:
The cement kiln, the preheater and the waste heat boiler are connected in sequence;
The inlet flue is connected with a discharge hole of the waste heat boiler; the inlet flue is sequentially provided with a smoke circulation inlet I, a dedusting material circulation inlet and an absorbent inlet; the desulfurization absorption tower is provided with a water spray gun;
A dust remover with a feeding hole connected with a discharging hole of the desulfurization absorption tower; the dedusting material outlet of the deduster is communicated with the dedusting material circulating inlet through an air chute, and the low-sulfur low-dust flue gas outlet is connected with a first flue gas pipeline;
The feed inlet is connected with the low-sulfur low-dust flue gas outlet of the dust remover through the first flue gas pipeline; the first flue gas pipeline is sequentially provided with a denitration inlet windshield, a flue gas circulation inlet II, a heating device and an ammonia spraying device; the top of the SCR denitration device is provided with a rectifying device, the side part of the SCR denitration device is provided with a soot blower, and a bottom purified gas outlet is connected with a second flue gas pipeline;
A chimney connected with a purified gas outlet of the SCR denitration device through the second flue gas pipeline; the second flue gas pipeline is sequentially provided with an ammonia water evaporation wind outlet, an induced draft fan and a purified gas circulation outlet; the ammonia water evaporation wind outlet is communicated with a feed inlet of the ammonia spraying device;
the purified gas circulation outlet is respectively communicated with the flue gas circulation inlet I and the flue gas circulation inlet II;
the dedusting material outlet is also connected with a desulfurization byproduct outer discharge port;
The smoke circulation inlet I is respectively communicated with the smoke circulation inlet II and the purified gas circulation outlet through a third smoke pipeline; the third flue gas pipeline is provided with a recirculation windshield.
2. The dry desulfurization and denitrification device according to claim 1, wherein the SCR denitrification device is matched with a medium-low temperature catalyst, and the temperature of a reaction window is 70-280 ℃.
3. The dry desulfurization and denitrification device according to claim 1, wherein the flue gas circulation inlet II is communicated with a third flue gas pipeline through a fourth flue gas pipeline; and the fourth flue gas pipeline is provided with a desulfurization recycling windshield.
4. The dry desulfurization and denitrification device according to claim 1, further comprising:
GGH heat exchanger on first flue gas pipeline and second flue gas pipeline.
5. A dry desulfurization and denitrification method suitable for cement kiln flue gas, which is characterized by adopting the dry desulfurization and denitrification device as claimed in claim 1, comprising the following steps:
a) Preheating cement kiln flue gas, performing dry desulfurization under the action of an absorbent, and then removing dust to obtain dust removing materials and low-sulfur low-dust flue gas respectively; wherein the dedusting material is subjected to the dry desulfurization in a circulating way;
b) And c) SCR denitration is carried out on the low-sulfur low-dust flue gas obtained in the step a) at 70-280 ℃ in the presence of ammonia water, so as to obtain purified gas.
6. The dry desulfurization and denitrification method according to claim 5, wherein the absorbent in the step a) is a calcium-based alkaline absorbent.
7. The method according to claim 5, wherein the outlet temperature of the dry desulfurization in the step a) is 70 ℃ to 110 ℃.
8. The method according to claim 5, wherein the purified gas obtained in step b) is recycled to assist in preheating the dry desulfurization and denitration apparatus.
9. The dry desulfurization and denitrification method according to any one of claims 5 to 8, further comprising:
And c), exchanging heat between the low-sulfur and low-dust flue gas obtained in the step a) and the purified gas obtained in the step b), and then performing SCR denitration.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910506499.6A CN110075681B (en) | 2019-06-12 | 2019-06-12 | Dry desulfurization and denitrification device and method suitable for cement kiln flue gas |
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| CN201910506499.6A CN110075681B (en) | 2019-06-12 | 2019-06-12 | Dry desulfurization and denitrification device and method suitable for cement kiln flue gas |
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| Publication Number | Publication Date |
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| CN110075681A CN110075681A (en) | 2019-08-02 |
| CN110075681B true CN110075681B (en) | 2024-05-28 |
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| CN110665352A (en) * | 2019-11-21 | 2020-01-10 | 福建龙净脱硫脱硝工程有限公司 | Dry desulfurization, denitrification and dust removal device and method for low-sulfur flue gas in cement kiln tail |
| CN110860196A (en) * | 2019-12-23 | 2020-03-06 | 福建龙净脱硫脱硝工程有限公司 | Desulfurization and denitrification system for cement flue gas |
| CN111359408B (en) * | 2020-04-30 | 2024-03-26 | 西安交通大学 | Desulfurization and denitration flue gas comprehensive treatment device and method for cooperative thermal power generation |
| CN111871175A (en) * | 2020-07-27 | 2020-11-03 | 蕉岭县龙腾旋窑水泥有限公司 | Dry desulfurization and denitrification device and method suitable for cement kiln flue gas |
| CN112933953A (en) * | 2021-04-06 | 2021-06-11 | 北京清新环境节能技术有限公司 | Flue gas treatment system |
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