CN113318592A - Kiln flue gas treatment device and method thereof - Google Patents
Kiln flue gas treatment device and method thereof Download PDFInfo
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- CN113318592A CN113318592A CN202110244204.XA CN202110244204A CN113318592A CN 113318592 A CN113318592 A CN 113318592A CN 202110244204 A CN202110244204 A CN 202110244204A CN 113318592 A CN113318592 A CN 113318592A
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- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 title claims abstract description 120
- 239000003546 flue gas Substances 0.000 title claims abstract description 120
- 238000000034 method Methods 0.000 title claims abstract description 32
- 239000000428 dust Substances 0.000 claims abstract description 117
- 238000006477 desulfuration reaction Methods 0.000 claims abstract description 37
- 230000023556 desulfurization Effects 0.000 claims abstract description 37
- 230000008030 elimination Effects 0.000 claims abstract description 10
- 238000003379 elimination reaction Methods 0.000 claims abstract description 10
- CPLXHLVBOLITMK-UHFFFAOYSA-N Magnesium oxide Chemical compound [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 claims description 50
- 239000000395 magnesium oxide Substances 0.000 claims description 27
- 230000003009 desulfurizing effect Effects 0.000 claims description 19
- 238000010438 heat treatment Methods 0.000 claims description 15
- 239000003054 catalyst Substances 0.000 claims description 14
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 13
- 238000005507 spraying Methods 0.000 claims description 11
- 230000002087 whitening effect Effects 0.000 claims description 9
- 238000002485 combustion reaction Methods 0.000 claims description 7
- 239000007921 spray Substances 0.000 claims description 7
- 238000006243 chemical reaction Methods 0.000 claims description 5
- 238000001816 cooling Methods 0.000 claims description 5
- 238000010992 reflux Methods 0.000 claims description 5
- 235000008733 Citrus aurantifolia Nutrition 0.000 claims description 3
- 235000011941 Tilia x europaea Nutrition 0.000 claims description 3
- 239000004571 lime Substances 0.000 claims description 3
- 239000011214 refractory ceramic Substances 0.000 claims description 3
- 230000001502 supplementing effect Effects 0.000 claims description 3
- 238000012546 transfer Methods 0.000 claims description 3
- 238000005338 heat storage Methods 0.000 claims 2
- 239000007789 gas Substances 0.000 abstract description 9
- 238000010531 catalytic reduction reaction Methods 0.000 abstract description 3
- 239000002912 waste gas Substances 0.000 abstract description 2
- 238000005516 engineering process Methods 0.000 description 13
- MWUXSHHQAYIFBG-UHFFFAOYSA-N nitrogen oxide Inorganic materials O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 description 12
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 7
- 239000011777 magnesium Substances 0.000 description 7
- 229910052749 magnesium Inorganic materials 0.000 description 7
- RAHZWNYVWXNFOC-UHFFFAOYSA-N sulfur dioxide Inorganic materials O=S=O RAHZWNYVWXNFOC-UHFFFAOYSA-N 0.000 description 7
- 239000003344 environmental pollutant Substances 0.000 description 5
- 231100000719 pollutant Toxicity 0.000 description 5
- 239000000779 smoke Substances 0.000 description 5
- AXZKOIWUVFPNLO-UHFFFAOYSA-N magnesium;oxygen(2-) Chemical compound [O-2].[Mg+2] AXZKOIWUVFPNLO-UHFFFAOYSA-N 0.000 description 4
- 238000006722 reduction reaction Methods 0.000 description 4
- 238000005260 corrosion Methods 0.000 description 3
- 230000007797 corrosion Effects 0.000 description 3
- 230000007613 environmental effect Effects 0.000 description 3
- 239000001095 magnesium carbonate Substances 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 239000002245 particle Substances 0.000 description 3
- 230000001105 regulatory effect Effects 0.000 description 3
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 2
- 239000003795 chemical substances by application Substances 0.000 description 2
- 239000000571 coke Substances 0.000 description 2
- 238000009833 condensation Methods 0.000 description 2
- 230000005494 condensation Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000005265 energy consumption Methods 0.000 description 2
- 230000005484 gravity Effects 0.000 description 2
- 238000012423 maintenance Methods 0.000 description 2
- 235000019738 Limestone Nutrition 0.000 description 1
- 241000276489 Merlangius merlangus Species 0.000 description 1
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 150000001412 amines Chemical class 0.000 description 1
- 229910021529 ammonia Inorganic materials 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000001354 calcination Methods 0.000 description 1
- 238000006555 catalytic reaction Methods 0.000 description 1
- 239000003245 coal Substances 0.000 description 1
- 239000011362 coarse particle Substances 0.000 description 1
- 239000000356 contaminant Substances 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 239000012717 electrostatic precipitator Substances 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 239000010881 fly ash Substances 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- 238000000227 grinding Methods 0.000 description 1
- 239000010440 gypsum Substances 0.000 description 1
- 229910052602 gypsum Inorganic materials 0.000 description 1
- 229910001385 heavy metal Inorganic materials 0.000 description 1
- 229910052500 inorganic mineral Inorganic materials 0.000 description 1
- 239000006028 limestone Substances 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 235000014380 magnesium carbonate Nutrition 0.000 description 1
- ZLNQQNXFFQJAID-UHFFFAOYSA-L magnesium carbonate Chemical compound [Mg+2].[O-]C([O-])=O ZLNQQNXFFQJAID-UHFFFAOYSA-L 0.000 description 1
- 229910000021 magnesium carbonate Inorganic materials 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 235000010755 mineral Nutrition 0.000 description 1
- 239000011707 mineral Substances 0.000 description 1
- MXWHMTNPTTVWDM-NXOFHUPFSA-N mitoguazone Chemical group NC(N)=N\N=C(/C)\C=N\N=C(N)N MXWHMTNPTTVWDM-NXOFHUPFSA-N 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 231100001143 noxa Toxicity 0.000 description 1
- 231100000572 poisoning Toxicity 0.000 description 1
- 230000000607 poisoning effect Effects 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
- 238000004064 recycling Methods 0.000 description 1
- 238000003303 reheating Methods 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 239000013535 sea water Substances 0.000 description 1
- 239000002893 slag Substances 0.000 description 1
- 230000000087 stabilizing effect Effects 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 239000011593 sulfur Substances 0.000 description 1
- 229910052717 sulfur Inorganic materials 0.000 description 1
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
- B01D53/86—Catalytic processes
- B01D53/8621—Removing nitrogen compounds
- B01D53/8625—Nitrogen oxides
- B01D53/8631—Processes characterised by a specific device
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D47/00—Separating dispersed particles from gases, air or vapours by liquid as separating agent
- B01D47/06—Spray cleaning
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D50/00—Combinations of methods or devices for separating particles from gases or vapours
-
- 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
- B01D53/005—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 by heat treatment
-
- 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
- B01D53/501—Sulfur oxides by treating the gases with a solution or a suspension of an alkali or earth-alkali or ammonium compound
- B01D53/504—Sulfur oxides by treating the gases with a solution or a suspension of an alkali or earth-alkali or ammonium compound characterised by a specific device
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
- B01D53/77—Liquid phase processes
- B01D53/79—Injecting reactants
-
- 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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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Environmental & Geological Engineering (AREA)
- Analytical Chemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Health & Medical Sciences (AREA)
- Biomedical Technology (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Treating Waste Gases (AREA)
Abstract
The invention relates to the technical field of industrial kiln waste gas treatment, in particular to a kiln gas treatment device and a kiln gas treatment method. The kiln flue gas treatment device comprises a kiln, a pre-dust removal device, a heat exchanger, an SCR (selective catalytic reduction) reactor and a dust removal, desulfurization and white elimination tower, wherein an outlet of the kiln is communicated with an inlet of the pre-dust removal device through a flue gas pipeline; the heat exchanger comprises a cold airflow side and a hot airflow side, wherein a cold airflow side inlet of the heat exchanger is communicated with an outlet of the pre-dust removal device through a communicating pipeline, a cold airflow side outlet of the heat exchanger is communicated with an inlet of the SCR reactor through a communicating pipeline, a hot airflow side inlet of the heat exchanger is communicated with an outlet of the SCR reactor, and a hot airflow side outlet of the heat exchanger is communicated with the desulfurization, dust removal and white elimination tower through a communicating pipeline, so that the integrated treatment of dust removal, desulfurization and denitration is realized, and the dust removal, desulfurization and denitration efficiency can reach more than 95%. The invention has the advantages of simple process, reasonable utilization of heat in flue gas, low cost, small occupied area and higher popularization value.
Description
Technical Field
The invention relates to the technical field of industrial kiln waste gas treatment, in particular to a kiln gas treatment device and a kiln gas treatment method.
Background
Magnesite and coke in the middle-grade magnesium kiln are put into a shaft kiln and heated to 800-1000 ℃ to generate light-burned magnesium oxide, then the light-burned magnesium oxide is crushed to 200-mesh and 250-mesh powder, pressed into balls and heated to 1800 ℃ at high temperature to generate heavy-burned magnesium oxide. Thus, the pollutants of the kiln include smoke and dust generated during calcination, and SO generated by combustion of sulfur in coal or coke2CO produced by decomposition of magnesite2And CO produced by combustion of fuel2CO and NOXEtc., wherein the above pollutants are mainly smoke dust and dust, SO2And NOXAs an auxiliary measure, the pollution discharge coefficient is about 32kg of dust generated by 1t of magnesium products. Therefore, a large amount of MgO dust and SO are discharged during the production of magnesite2、NOXThe dust causes serious environmental pollution, not only pollutes the atmospheric environment, but also reduces the atmospheric visibility, has great influence on organisms and reduces the quality of the whole ecological environment.
Although the dust removal, desulfurization and denitrification technologies of the existing power plant are mature, the technologies are as follows: the desulfurization process is classified into a dry method, a semi-dry method and a wet method according to the form of a desulfurizing agent. The dry method and the semi-dry method have the characteristics of low investment and low energy consumption, occupy certain market share in the field of small and medium-sized coal-fired boilers, but the desulfurization efficiency is usually not higher than 90 percent, and the wet method desulfurization can reach more than 95 percent, so that the method is a main direction for the development of desulfurization process technology in China in future. The wet process may be classified into a limestone/gypsum process, a seawater process, an ammonia process, a double alkali process, a magnesium process, an organic amine process, etc., according to the nature of the desulfurizing agent.
The existing denitration technology comprises the following steps: currently NOXThere are two main types of removal: one is to control the generation of nitrogen oxides by improving the combustion technology, the efficiency is about 30-50 percent, the method has low efficiency, and the pipeline in the furnace is easy to slag; the second method is a selective catalytic reduction denitration technology (SCR) widely applied in countries of Europe, America, Japan and the like, the denitration efficiency is generally about 50-90%, the catalytic reaction of the method needs to be carried out in a high-temperature section of flue gas, the reaction temperature is 320-400 ℃, but the flue gas is not dedusted in the high-temperature section, the dust in the flue gas is more, the blockage and grinding of a flue between reactors are easily caused, heavy metals in the fly ash can also cause the poisoning of a catalyst, the denitration efficiency is reduced, the operation and investment cost of the selective catalytic reduction denitration technology (SCR) is very expensive, and the production cost of enterprises is increased.
The existing dust removal technology: at present, four dust removal modes are mainly adopted: firstly, a mechanical dust remover; secondly, an electric dust remover; thirdly, a bag type dust collector; wet dust collector.
The mechanical dust collector comprises a gravity settling chamber, an inertial dust collector, a cyclone dust collector and the like. The gravity settling chamber has simple structure, less investment, small pressure loss and easy maintenance and management, but has large volume and low efficiency, and can only be used as a pre-dedusting device for high-efficiency dedusting to remove larger and heavier particles; the inertial dust collector has higher dust collection efficiency for metal or mineral dust with larger density and particle size, and can be used as the first stage of multi-stage dust collection to collect coarse particle size of more than 10-20 mu m; the cyclone dust collector has the characteristics of simple structure, wide application, various varieties and the like.
The electric dust remover has the characteristics of low energy consumption and low airflow resistance, and can effectively capture submicron-grade particles.
The dust removal efficiency of the bag type dust collector can reach more than 99 percent generally. Because of high efficiency, stable and reliable performance and simple operation, the material is more and more widely applied, but is not easy to process airflow with high humidity and high viscosity, because the material is limited by moisture resistance and corrosion resistance, and the smoke temperature is less than 300 ℃.
The electric dust remover is a novel high-efficiency dust remover which combines an electric dust removal technology and a bag type dust removal technology, and the dust removal filtration is as high as more than 99.9 percent.
The wet dust collector has the advantages of high dust collection efficiency, simple structure, small occupied area, low one-time investment and convenient operation and maintenance. Can treat high-temperature, high-humidity or high-viscosity dust-containing gas, has the function of removing gaseous pollutants, and is particularly suitable for occasions where the production process is provided with water treatment equipment.
The existing white elimination technology: the currently common equipment for desulfurization and white smoke abatement is an MGGH system, flue gas enters a desulfurizing tower after being dedusted by a deduster, and the desulfurized flue gas is heated by a flue gas heater and then discharged through a chimney. The flue gas heater is heated by water heated by the hot water heater, and the water after heat exchange in the flue gas heater returns to the hot water heater for reheating and is conveyed to the flue gas heater through the circulating pump for recycling.
However, the smoke of the medium magnesia kiln has the following characteristics: the fluctuation range of the flue gas temperature is large, the flue gas temperature is 50-800 ℃, the dust content of the flue gas is large, the flue gas humidity is high, and the flue gas purification treatment difficulty is very large. Therefore, how to apply the technology to the treatment of the flue gas of the magnesium kiln is difficult, a technical route which is reliable in technology, high in feasibility and acceptable to magnesium kiln enterprises at cost needs to be selected according to the characteristics of the flue gas, and no related patent exists at present
Disclosure of Invention
The invention aims to at least solve one of the technical problems in the prior art and provides a kiln flue gas treatment device and a kiln flue gas treatment method.
In order to achieve the purpose, the technical scheme adopted by the invention is as follows: a kiln flue gas treatment device comprises a kiln, a pre-dust removal device, a heat exchanger, an SCR reactor and a dust removal, desulfurization and white reduction tower, wherein an outlet of the kiln is communicated with an inlet of the pre-dust removal device through a flue gas pipeline; the heat exchanger comprises a cold airflow side and a hot airflow side, wherein a cold airflow side inlet of the heat exchanger is communicated with an outlet of the pre-dust removal device through a communicating pipeline, a cold airflow side outlet of the heat exchanger is communicated with an inlet of the SCR reactor through a communicating pipeline, a hot airflow side inlet of the heat exchanger is communicated with an outlet of the SCR reactor, and a hot airflow side outlet of the heat exchanger is communicated with the desulfurization dust removal white-eliminating tower through a communicating pipeline.
Further, the pre-dust removal device comprises a primary dust remover and a secondary dust remover, wherein the primary dust remover comprises one or more of a mechanical dust remover, a multi-pipe cyclone dust remover and a PV high-efficiency cyclone dust remover; the secondary dust remover comprises at least one of a wet mechanical dust remover, a wet electric dust remover and a dust remover which is integrally or separately arranged with the desulfurizing tower.
Further, a heat accumulator and a catalyst are arranged in the SCR reactor, and the heat accumulator is arranged at the front end of the catalyst.
Furthermore, the heat accumulator is made into a honeycomb shape by adopting refractory ceramics.
Furthermore, a first branch is arranged at the rear end of the SCR reactor and communicated with a flue gas pipeline at the kiln outlet.
Further, a first fan is arranged between the first branch and the flue gas pipeline at the kiln outlet, and the first fan is used for conveying the denitrated flue gas to the flue gas pipeline at the kiln outlet.
Furthermore, a second branch is arranged at an outlet on the cold airflow side of the heat exchanger, a second fan and a combustion-supporting furnace are sequentially arranged on the second branch, the second fan is used for sending part of the flue gas subjected to preliminary temperature rise by the heat exchanger to the combustion-supporting furnace, and the combustion-supporting furnace is used for supporting combustion and raising the temperature of the flue gas.
Furthermore, a third fan is arranged on a pipeline of which a hot airflow side outlet of the heat exchanger is communicated with the desulfurization, dust removal and white reduction tower, and the third fan is used for exchanging heat and cooling the denitrated flue gas with cold airflow through the hot airflow side of the heat exchanger and then introducing the denitrated flue gas into the desulfurization and white reduction tower for treatment; a turbulent device, a spraying device, a vortex spray dust removal device and a heating device are arranged in the dedusting, desulfurization and whiting tower, a certain water film is generated at the upper part of the turbulent device during the desulfurization operation, and the water film is used for increasing mass transfer and trapping dust; the spraying device is provided with 2-4 spraying layers according to different desulfurization efficiencies; the vortex spraying dust removal device is formed by combining a rotational flow device arranged at the lower end and a turbulent flow device arranged at the upper end; the heating device adopts an indirect heating mode.
Further, the kiln comprises one or more of a middle-grade magnesia shaft kiln, a middle-grade magnesia kiln, a high-purity magnesia kiln, a dead-burned magnesia kiln, a light-burned magnesia kiln and a lime shaft kiln.
A kiln flue gas treatment method utilizes the kiln flue gas treatment device, and comprises the following steps:
step one, pre-dedusting: flue gas in the kiln enters a pre-dedusting device for pre-dedusting;
step two, flue gas temperature regulation: heating the flue gas by adopting a flue gas reflux, heat accumulator and afterburning furnace heat supplementing mode, so that the temperature of the flue gas entering the SCR reactor is between 250 ℃ and 400 ℃;
step three, denitration: carrying out denitration reaction on the flue gas in an SCR reactor;
step four, deep dust removal, desulfurization and whitening: after denitration, the flue gas is subjected to heat exchange and cooling with cold airflow through the hot airflow side of the heat exchanger, then is guided to the dedusting, desulfurizing and whitening tower by the third fan for treatment, and is discharged into the atmosphere after being treated by the dedusting, desulfurizing and whitening tower.
The invention has the beneficial effects that: as can be seen from the above description of the present invention, compared with the prior art, (1) the present invention can remove the nitrogen oxides in the flue gas of the magnesia shaft kiln to 100mg/Nm by performing the dust removal, denitration, desulfurization and white elimination treatment on the flue gas of the magnesia shaft kiln3The sulfur dioxide is removed to 30mg/Nm3Dust removal to 10mg/Nm3The following can reach the limit value regulated by the local environmental protection department.
(2) The dust removal, desulfurization and denitrification integrated treatment method disclosed by the invention has the advantages that the dust removal efficiency can reach 95%, the desulfurization efficiency can reach more than 95%, and the denitrification efficiency can reach more than 95%.
(3) According to the invention, the flue gas is heated in a flue gas reflux, heat accumulator and heating furnace heat supplementing manner, so that the temperature of the flue gas entering the denitration reactor is between 250 ℃ and 400 ℃, the use of the catalyst is ensured, and the catalyst is prevented from being damaged.
(4) The invention adopts the modes of flue gas reflux and afterburning heating to keep the temperature of the flue gas above the dew point, thereby effectively avoiding the corrosion and blockage of the pre-dust remover caused by condensation of water in the flue gas;
(5) the invention has the advantages of simple process, reasonable utilization of heat in flue gas, low cost, small occupied area and higher popularization value.
Drawings
FIG. 1 is a schematic structural diagram of kiln flue gas treatment in a preferred embodiment of the invention.
Reference numerals: 1. a kiln; 2. a pre-dust removal device; 3. a heat exchanger; 4. a second fan; 5. a combustion-supporting furnace; 6. an SCR reactor; 61. a heat accumulator; 62. a catalyst body; 7. a third fan; 8. the dedusting, desulfurizing and white-removing tower; 81. a turbulent device; 82. a spraying device; 83. a vortex spray dust removal device; 84. a heating device; 9. a first fan.
Detailed Description
The technical solutions in the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments.
In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "connected" and "connected" are to be interpreted broadly, e.g., as being fixed or detachable or integrally connected; can be mechanically or electrically connected; may be directly connected or indirectly connected through an intermediate. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.
Referring to fig. 1, a preferred embodiment of the present invention, a kiln flue gas treatment device, includes a kiln 1, a pre-dust removal device 2, a heat exchanger 3, an SCR reactor 6, and a dust removal, desulfurization and white elimination tower 8, where the kiln 1 includes a medium magnesia kiln, a high-purity magnesia kiln, a dead-burned magnesia kiln, a light-burned magnesia kiln, a lime kiln, and the like, and this example takes the medium magnesia kiln as an example for description. The outlet of the middle-grade kiln is communicated with the inlet of the pre-dedusting device 2 through a flue gas pipeline; the heat exchanger 3 comprises a cold gas flow side and a hot gas flow side,the cold airflow side inlet of the heat exchanger is communicated with the outlet of the pre-dedusting device 2 through a communicating pipeline, the cold airflow side outlet of the heat exchanger 3 is communicated with the inlet of the SCR reactor 6 through a communicating pipeline, the hot airflow side inlet of the heat exchanger 3 is communicated with the outlet of the SCR reactor 6, and the hot airflow side outlet of the heat exchanger 3 is communicated with the desulfurization dust-removal white-removal tower 8 through a communicating pipeline, so that after the magnesia shaft kiln flue gas is subjected to dust removal, denitration, desulfurization and white-removal treatment, the nitrogen oxide in the magnesia shaft kiln flue gas can be removed to 100mg/Nm3The sulfur dioxide is removed to 30mg/Nm3Dust removal to 10mg/Nm3The following can reach the limit value regulated by the local environmental protection department.
As a preferred embodiment of the present invention, it may also have the following additional technical features: the pre-dust removal device 2 comprises a primary dust remover and a secondary dust remover, wherein the primary dust remover comprises one or more of a mechanical dust remover, a multi-pipe cyclone dust remover and a PV high-efficiency cyclone dust remover, and the embodiment takes the high-efficiency multi-pipe cyclone dust remover as an example for explanation; the second grade dust remover includes wet process mechanical dust remover, wet-type electrostatic precipitator, and at least one of the dust remover of arranging or components of a whole that can function independently arranging with the desulfurizing tower, wherein when adopting and arranging with the desulfurizing tower is integrative, this desulfurization part adopts wet flue gas desulfurization, and the desulfurizer adopts magnesium oxide.
In this embodiment, a heat accumulator 61 and a catalyst 62 are arranged in the SCR reactor 6, the heat accumulator 61 is arranged at the front end of the catalyst 62, and the heat accumulator 61 is made into a honeycomb shape by using refractory ceramics, so that high-temperature flue gas absorbs heat, and low-temperature flue gas releases heat, thereby playing a certain role in stabilizing the temperature of the flue gas; and the rear end of the SCR reactor 6 is provided with a first branch which is communicated with the flue gas pipeline at the kiln outlet, and a first fan 9 is arranged between the first branch and the flue gas pipeline at the kiln outlet, so that the denitrated flue gas is delivered to the flue gas pipeline at the kiln outlet through a thermal circulation fan, is fully mixed with the original flue gas and then enters the high-efficiency pre-dedusting device, the temperature of the flue gas entering the denitration reactor is between 250 ℃ and 400 ℃, the use of the catalyst is ensured, and the catalyst is prevented from being damaged.
In the embodiment, in order to reduce the heat required by the supplementary combustion of the flue gas, the heat exchanger 3 is arranged to exchange heat with the flue gas; meanwhile, a second branch is arranged at an outlet on the cold airflow side of the heat exchanger 3, and a second fan 4 and a combustion-supporting furnace 5 are sequentially arranged on the second branch, so that part of flue gas subjected to preliminary temperature rise by the heat exchanger enters the combustion-supporting furnace through the combustion-supporting fan to support combustion and raise temperature, and then enters the SCR reactor after being mixed with non-afterburning flue gas to carry out SCR denitration, the flue gas temperature is kept above a dew point by adopting a flue gas backflow and afterburning heating mode, and the corrosion and blockage of a pre-dust remover caused by condensation of water in the flue gas are effectively avoided.
In this embodiment, a third fan 7 is arranged on a pipeline connecting an outlet on a hot airflow side of the heat exchanger 3 with the desulfurization, dust removal and white elimination tower 8, and the third fan 7 is used for introducing the denitrated flue gas into the desulfurization and white elimination tower for treatment after heat exchange and cooling with cold airflow through the hot airflow side of the heat exchanger; a turbulent device 81, a spraying device 82, a vortex spray dust removal device 83 and a heating device 84 are arranged in the dedusting, desulfurizing and white-eliminating tower 8, a certain water film is generated at the upper part of the turbulent device 81 during the desulfurizing operation, and the water film has certain dust trapping effect while the mass transfer effect is increased; the spraying device 82 is provided with 2-4 spraying layers according to different desulfurization efficiencies; the vortex spray dust removal device 83 is formed by combining a rotational flow device arranged at the lower end and a turbulent flow device arranged at the upper end, so that saturated clean flue gas containing a large amount of liquid drops at 50 ℃ passes through the high-efficiency vortex spray dust removal device from bottom to top; the heating device 84 adopts an indirect heating mode, and a heat source can adopt hot flue gas.
A kiln flue gas treatment method utilizes the kiln flue gas treatment device, and comprises the following steps:
step one, pre-dedusting: flue gas in the kiln enters a pre-dedusting device for pre-dedusting;
step two, flue gas temperature regulation: the flue gas is heated by adopting the modes of flue gas reflux, heat accumulator and afterburning furnace heat compensation, so that the temperature of the flue gas entering the SCR reactor is between 250 ℃ and 400 ℃, the use of the catalyst is ensured, and the catalyst is prevented from being damaged;
step three, denitration: carrying out denitration reaction on the flue gas in an SCR reactor;
step four, deep dust removal, desulfurization and whitening: after denitration, the flue gas is subjected to heat exchange and cooling with cold airflow through the hot airflow side of the heat exchanger, then is guided to the dedusting, desulfurizing and whitening tower by the third fan for treatment, and is discharged into the atmosphere after being treated by the dedusting, desulfurizing and whitening tower.
The specific embodiment is as follows: the middle-grade magnesia shaft kiln flue gas is subjected to preliminary dust removal through the high-efficiency multi-pipe cyclone dust collector, then is subjected to preliminary temperature rise through the cold air flow side of the heat exchanger, part of the flue gas enters the combustion-supporting furnace through the combustion-supporting fan to be mixed with unburnt flue gas after being subjected to combustion-supporting temperature rise, then enters the SCR reactor to be subjected to denitration reaction, and the flue gas after denitration is introduced to the deep dust removal desulfurization and white elimination tower through the draught fan after being subjected to heat exchange and temperature reduction through the hot air flow side of the heat exchanger and the cold air flow and then is discharged into the atmosphere.
And (3) detecting the content of pollutants: the untreated magnesium kiln flue gas at the flue gas inlet and the treated magnesium kiln flue gas at the chimney were taken for determination of the pollutant content, and the results are shown in table 1.
TABLE 1 untreated kiln gas and treated kiln gas contaminant content
As can be seen from the above table, the nitrogen oxides in the flue gas of the magnesia shaft kiln after desulfurization, denitrification, dust removal and white removal are removed to 100mg/Nm3The sulfur dioxide is removed to 30mg/Nm3Dust removal to 10mg/Nm3The following can reach the limit value regulated by the local environmental protection department.
The above additional technical features can be freely combined and used in superposition by those skilled in the art without conflict.
It is to be understood that the present invention has been described with reference to certain embodiments, and that various changes in the features and embodiments, or equivalent substitutions may be made therein by those skilled in the art without departing from the spirit and scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.
Claims (10)
1. The utility model provides a kiln flue gas treatment device which characterized in that: the device comprises a kiln (1), a pre-dust removal device (2), a heat exchanger (3), an SCR reactor (6) and a dedusting, desulfurizing and white-eliminating tower (8), wherein an outlet of the kiln (2) is communicated with an inlet of the pre-dust removal device (2) through a flue gas pipeline; the heat exchanger (3) comprises a cold airflow side and a hot airflow side, an inlet of the cold airflow side of the heat exchanger (3) is communicated with an outlet of the pre-dust removal device (2) through a communicating pipeline, an outlet of the cold airflow side of the heat exchanger (3) is communicated with an inlet of the SCR reactor (6) through a communicating pipeline, an inlet of the hot airflow side of the heat exchanger (3) is communicated with an outlet of the SCR reactor (6), and an outlet of the hot airflow side of the heat exchanger (3) is communicated with the desulfurization dust removal white-eliminating tower through a communicating pipeline.
2. The kiln flue gas treatment device according to claim 1, wherein: the pre-dust removal device (2) comprises a primary dust remover and a secondary dust remover, wherein the primary dust remover comprises one or more of a mechanical dust remover, a multi-pipe cyclone dust remover and a PV high-efficiency cyclone dust remover; the secondary dust remover comprises at least one of a wet mechanical dust remover, a wet electric dust remover and a dust remover which is integrally or separately arranged with the desulfurizing tower.
3. The kiln flue gas treatment device according to claim 1, wherein: a heat storage body (61) and a catalyst body (62) are arranged in the SCR reactor (6), and the heat storage body (61) is arranged at the front end of the catalyst body (62).
4. The kiln flue gas treatment device according to claim 3, wherein: the heat accumulator (61) is made into a honeycomb shape by adopting refractory ceramics.
5. The kiln flue gas treatment device according to claim 1, wherein: and a first branch is arranged at the rear end of the SCR reactor (6) and communicated with a flue gas pipeline at the kiln outlet.
6. The kiln flue gas treatment device according to claim 5, wherein: a first fan (9) is arranged between the first branch and the flue gas pipeline at the kiln outlet, and the first fan (9) is used for conveying the denitrated flue gas to the flue gas pipeline at the kiln outlet.
7. The kiln flue gas treatment device according to claim 1, wherein: the cold airflow side outlet of the heat exchanger (3) is provided with a second branch, a second fan (4) and a combustion-supporting furnace (5) are sequentially arranged on the second branch, the second fan (4) is used for conveying part of flue gas subjected to preliminary temperature rise by the heat exchanger (3) to the combustion-supporting furnace (5), and the combustion-supporting furnace (5) is used for supporting combustion and raising the temperature of the flue gas.
8. The kiln flue gas treatment device according to claim 1, wherein: a third fan (7) is arranged on a pipeline of a hot airflow side outlet of the heat exchanger (3) communicated with the desulfurization, dust removal and white elimination tower, and the third fan (7) is used for exchanging heat and reducing temperature of the denitrated flue gas through the hot airflow side and the cold airflow side of the heat exchanger (3) and then introducing the denitrated flue gas into the dust removal, desulfurization and white elimination tower (8) for treatment; a turbulent device (81), a spraying device (82), a vortex spray dust removal device (83) and a heating device (84) are arranged in the dedusting, desulfurizing and white-eliminating tower (8), a certain water film is generated at the upper part of the turbulent device (81) during the desulfurizing operation, and the water film is used for increasing mass transfer and trapping dust; the spraying device (82) is provided with 2-4 spraying layers according to different desulfurization efficiencies; the vortex spray dust removal device (83) is formed by combining a cyclone device arranged at the lower end and a turbulent device (81) arranged at the upper end; the heating device (84) adopts an indirect heating mode.
9. The kiln flue gas treatment device according to claim 1, wherein: the kiln comprises one or more of a middle-grade magnesia shaft kiln, a middle-grade magnesia kiln, a high-purity magnesia kiln, a dead-burned magnesia kiln, a light-burned magnesia kiln and a lime shaft kiln.
10. A method for treating kiln flue gas is characterized by comprising the following steps: the kiln flue gas treatment device of any one of claims 1 to 9, comprising the following steps:
step one, pre-dedusting: flue gas in the kiln enters a pre-dedusting device for pre-dedusting;
step two, flue gas temperature regulation: heating the flue gas by adopting a flue gas reflux, heat accumulator and afterburning furnace heat supplementing mode, so that the temperature of the flue gas entering the SCR reactor is between 250 ℃ and 400 ℃;
step three, denitration: carrying out denitration reaction on the flue gas in an SCR reactor;
step four, deep dust removal, desulfurization and whitening: after denitration, the flue gas is subjected to heat exchange and cooling with cold airflow through the hot airflow side of the heat exchanger, then is guided to the dedusting, desulfurizing and whitening tower by the third fan for treatment, and is discharged into the atmosphere after being treated by the dedusting, desulfurizing and whitening tower.
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| CN113959229A (en) * | 2021-10-22 | 2022-01-21 | 无锡雪浪环境科技股份有限公司 | Tail gas purification system of precious metal-containing sludge resource roasting furnace |
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