CN112212702A - Cement kiln bypass air-bleeding energy-saving emission-reduction comprehensive utilization system and process - Google Patents
Cement kiln bypass air-bleeding energy-saving emission-reduction comprehensive utilization system and process Download PDFInfo
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- CN112212702A CN112212702A CN202011069284.1A CN202011069284A CN112212702A CN 112212702 A CN112212702 A CN 112212702A CN 202011069284 A CN202011069284 A CN 202011069284A CN 112212702 A CN112212702 A CN 112212702A
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- 239000004568 cement Substances 0.000 title claims abstract description 30
- 238000000034 method Methods 0.000 title claims abstract description 28
- 238000010791 quenching Methods 0.000 claims abstract description 85
- 230000000171 quenching effect Effects 0.000 claims abstract description 85
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 claims abstract description 76
- 239000003546 flue gas Substances 0.000 claims abstract description 76
- 238000002156 mixing Methods 0.000 claims abstract description 66
- 239000000779 smoke Substances 0.000 claims abstract description 47
- 238000001816 cooling Methods 0.000 claims abstract description 41
- 239000000428 dust Substances 0.000 claims abstract description 36
- 239000000203 mixture Substances 0.000 claims abstract description 5
- 239000002918 waste heat Substances 0.000 claims description 15
- 238000005516 engineering process Methods 0.000 claims description 5
- 238000009434 installation Methods 0.000 claims 1
- 238000004519 manufacturing process Methods 0.000 abstract description 14
- 230000007613 environmental effect Effects 0.000 abstract description 5
- 238000005265 energy consumption Methods 0.000 abstract description 2
- 239000003513 alkali Substances 0.000 description 6
- 230000000694 effects Effects 0.000 description 5
- 239000007789 gas Substances 0.000 description 5
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 4
- 239000000460 chlorine Substances 0.000 description 4
- 229910052801 chlorine Inorganic materials 0.000 description 4
- 238000006722 reduction reaction Methods 0.000 description 4
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 3
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 3
- 235000011114 ammonium hydroxide Nutrition 0.000 description 3
- 238000002485 combustion reaction Methods 0.000 description 3
- MWUXSHHQAYIFBG-UHFFFAOYSA-N nitrogen oxide Inorganic materials O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- 229910052717 sulfur Inorganic materials 0.000 description 3
- 239000011593 sulfur Substances 0.000 description 3
- 230000000903 blocking effect Effects 0.000 description 2
- 238000010531 catalytic reduction reaction Methods 0.000 description 2
- 239000003245 coal Substances 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 239000000725 suspension Substances 0.000 description 2
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 1
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- QGZKDVFQNNGYKY-UHFFFAOYSA-N ammonia Natural products N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- 238000002955 isolation Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000011591 potassium Substances 0.000 description 1
- 229910052700 potassium Inorganic materials 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- 150000003464 sulfur compounds Chemical class 0.000 description 1
- 231100000331 toxic Toxicity 0.000 description 1
- 230000002588 toxic effect Effects 0.000 description 1
- 238000009423 ventilation Methods 0.000 description 1
- 239000002912 waste gas Substances 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
Images
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
- F27D17/00—Arrangements for using waste heat; Arrangements for using, or disposing of, waste gases
- F27D17/004—Systems for reclaiming waste heat
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23L—SUPPLYING AIR OR NON-COMBUSTIBLE LIQUIDS OR GASES TO COMBUSTION APPARATUS IN GENERAL ; VALVES OR DAMPERS SPECIALLY ADAPTED FOR CONTROLLING AIR SUPPLY OR DRAUGHT IN COMBUSTION APPARATUS; INDUCING DRAUGHT IN COMBUSTION APPARATUS; TOPS FOR CHIMNEYS OR VENTILATING SHAFTS; TERMINALS FOR FLUES
- F23L15/00—Heating of air supplied for combustion
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
- F27D17/00—Arrangements for using waste heat; Arrangements for using, or disposing of, waste gases
- F27D17/008—Arrangements for using waste heat; Arrangements for using, or disposing of, waste gases cleaning gases
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E20/00—Combustion technologies with mitigation potential
- Y02E20/34—Indirect CO2mitigation, i.e. by acting on non CO2directly related matters of the process, e.g. pre-heating or heat recovery
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Environmental & Geological Engineering (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Chimneys And Flues (AREA)
Abstract
The invention relates to a cement kiln bypass air-bleeding energy-saving emission-reducing comprehensive utilization system and a process, which are mainly applied to cement production enterprises. The device comprises a kiln tail smoke chamber, a primary quenching device, a primary quenching fan, an SNCR denitration device, a secondary air mixing fan, an air preheater, an air blower, a dust collector, a tail exhaust fan, a kiln tail chimney and a hot air using device. Wherein kiln tail smoke chamber, one-level rapid cooling device, second grade mix wind device, air heater, dust collector, tail exhaust fan and kiln tail chimney pass through the flue and connect gradually in proper order, and wherein one-level rapid cooling device and second grade mix wind device and all adopt air cooling, for reaching the environmental protection requirement, set up SNCR denitrification facility in the system. The system can quickly and effectively reduce the temperature of the bypass air-bleeding flue gas, avoid blockage in the pipeline, effectively utilize the heat in the flue gas, reduce the energy consumption of the system and meet the requirement of environmental protection.
Description
Technical Field
The invention relates to an energy-saving and emission-reducing system and process, in particular to a cement kiln bypass air-bleeding energy-saving and emission-reducing comprehensive utilization system and process, which are mainly used for cement production enterprises.
Background
When the content of harmful elements in the cement raw combustion material is high or when the cement kiln is used for cooperatively treating wastes, the contents of chlorine, sulfur, alkali and other harmful substances entering the kiln system exceed the standard, the harmful substances are circularly enriched in the system, and particularly the concentrations of alkali, chlorine, sulfur compounds and nitrogen oxides in a kiln tail smoke chamber reach the highest value. This can lead to the phenomenon of skinning, blocking of smoke chamber, decomposing furnace and part of cyclone, and system discharge does not reach standard. This will affect the normal operation of the system, and in severe cases, may even result in a reduction in production and a shutdown of the system. In order to eliminate the adverse effect of elements such as chlorine, sulfur, alkali and the like on cement production, a bypass air release technology is mainly adopted to solve the problems at present.
The bypass air release technology is a measure for opening an air release opening at a position with high concentration of R +, Cl-and S, NOx in a tail smoke chamber of a cement kiln to release part of high-temperature kiln gas and dust so as to reduce the content of R +, Cl-and S and the content of NOx, reduce the phenomena of skinning and blocking and improve the quality of cement clinker products. Wherein, the high-temperature kiln gas is discharged into the atmosphere after being cooled and dedusted; the collected dust is homogenized through batching and warehousing or discarded.
The current bypass ventilation technology mainly has the following problems in the implementation process. Firstly, high-temperature flue gas in a kiln tail smoke chamber contains dust, and a large amount of alkaline compounds are also arranged on the surface of the dust, so that the dust has high viscosity, and the problem of kiln dust adhesion and blockage exists in the air intake process; secondly, the extracted high-temperature flue gas is discharged into the atmosphere after being cooled and dedusted, the heat of the high-temperature flue gas is not recovered, and the heat consumption of the cement kiln is increased; thirdly, the air quantity of the system can be greatly increased only by adopting the air mixing mode to cool the high-temperature flue gas, so that the selection of the dust collector and the tail exhaust fan is increased, and the manufacturing cost of the system is higher; fourthly, the operation temperature of the rotary kiln reaches more than 1600 ℃, a large amount of NOx which mainly takes a thermal type and a fuel type is generated while various toxic and harmful substances are solidified and decomposed, the concentration of the NOx in smoke of a smoke chamber can even reach more than 1500mg/Nm3, and the emission of a chimney is directly arranged to be difficult to meet the requirement of environmental protection emission;
disclosure of Invention
In view of the problems in the prior art, the technical problem to be solved by the invention is to provide a cement kiln bypass air-bleeding energy-saving emission-reduction comprehensive utilization system and process, which can comprehensively utilize the heat in bypass air-bleeding high-temperature flue gas, reduce the energy consumption of cement production, save the cost of the system and meet increasingly strict environmental protection emission requirements.
The technical scheme adopted by the invention is as follows: a cement kiln bypass air-bleeding energy-saving emission-reduction comprehensive utilization system and a process thereof comprise a kiln tail smoke chamber, a primary quenching device, a primary quenching fan, an SNCR denitration device, a secondary air mixing fan, an air preheater, an air blower, a dust collector, a tail exhaust fan, a kiln tail chimney and a hot air using device; the kiln tail smoke chamber, the primary quenching device, the SNCR denitration device, the secondary air mixing device, the air preheater, the dust collector, the tail exhaust fan and the kiln tail chimney are sequentially connected through a flue; the cooling air inlet of the primary quenching device is connected with the outlet of the primary quenching fan, and the inlet of the primary quenching fan is connected with air; a cooling air inlet of the secondary air mixing device is connected with an outlet of a secondary air mixing fan, and an inlet of the secondary air mixing fan is connected with air; the air inlet of the air preheater is connected with the outlet of the air blower, and the air outlet of the air preheater is connected with the inlet of the hot air using device.
The hot air using device is a tertiary air pipe or a kiln tail SP waste heat boiler or a kiln head AQC waste heat boiler.
The flue gas outlet of the primary quenching device, the flue gas outlet of the secondary air mixing device, the hot air outlet of the air preheater and the hot flue gas outlet of the air preheater are respectively provided with a thermocouple.
The primary quenching device is connected with a primary quenching fan and is provided with a valve for controlling air quantity; the secondary air mixing device and the secondary air mixing fan are connected with an air pipe, and a valve for controlling air quantity is arranged on the air pipe; and a valve for controlling the air quantity is arranged on the air inlet of the air preheater and the air blower connecting air pipe.
The first-stage quenching device adopts a volute structure or a sleeve structure.
The first-stage quenching device of the volute structure is cylindrical, two ends of the cylinder are connected with a flue gas pipeline, and a cooling air inlet is arranged at the tangential position of the side surface of the cylinder.
The primary quenching device of the sleeve structure is composed of two concentric sleeves inside and outside, and the end part of each sleeve is provided with an end plate, so that a closed cavity is formed between the two sleeves; wherein, interior sleeve pipe both ends are connected with flue gas pipeline, offer a plurality of holes on the interior sleeve pipe circumference wall, and the outer tube pipe wall is equipped with the cooling air entry.
The temperature of the smoke outlet of the first-stage quenching device is 500-1100 ℃, the temperature of the smoke outlet of the second-stage air mixing device is 300-950 ℃, the temperature of the hot air outlet of the air preheater is 200-800 ℃, and the temperature of the hot smoke outlet of the air preheater is 100-360 ℃.
The working process of the invention is as follows: an air discharge opening is formed in an enrichment part of a tail smoke chamber R +, Cl-S, NOx of the cement kiln, part of high-temperature smoke with high R +, Cl-S, NOx content and 1200 ℃ is extracted through a bypass air intake flue, the high-temperature smoke enters a primary quenching device through a flue and is mixed and cooled with cold air from an outlet of a primary quenching fan, and in order to prevent viscous dust in the smoke from being blocked on the inner wall surface of the primary quenching device, the primary quenching device adopts a volute structure or a sleeve structure. The first-stage quenching device of the volute structure is simple in structure, cooling air enters from the tangential direction and moves along the wall surface due to the inertia effect, so that hot flue gas is wrapped in the cooling air, and dust is prevented from being bonded and blocked on the wall surface; the one-level quenching device of the sleeve structure has the advantages that cooling air enters from small holes in the wall surface of the inner sleeve to generate certain air pressure, dust is prevented from being bonded and blocked on the wall surface, and meanwhile, the cooling air can be effectively mixed with smoke to reduce the temperature. The temperature of the flue gas cooled by the primary quenching device is reduced to 500-1100 ℃, and the cooling air quantity entering the primary quenching device is adjusted by adjusting the opening degree of a valve on an air pipe connected with the primary quenching device and a primary quenching fan, so that the temperature of the cooled flue gas is optimally 850-1050 ℃. The flue gas then enters an SNCR denitration device to remove NOx in the flue gas. The denitrated flue gas enters a secondary air mixing device, is fully mixed with cold air at the outlet of a secondary air mixing fan and is cooled to 300-950 ℃, and the cooling air quantity entering the secondary air mixing device is adjusted by adjusting the opening degree of a valve on an air pipe connecting the secondary air mixing device and the secondary air mixing fan, so that the temperature of the cooled flue gas is optimal to 650 ℃. The hot flue gas cooled by the secondary air mixing device enters an air preheater, and exchanges heat with cold air input by an air blower through a heat exchange surface of the air preheater, the temperature of the air is increased to 200-800 ℃ after heat exchange, and the temperature of the flue gas after heat exchange is reduced to 100-360 ℃. The opening degree of a valve on an air inlet of the air preheater and an air pipe connected with a blower is adjusted, and the amount of cold air input into the air preheater is adjusted, so that the outlet temperature of hot air after heat exchange of the air preheater is optimally 450-550 ℃, and the temperature of outlet flue gas after heat exchange of the air preheater is optimally 160 ℃. Then the flue gas enters a dust collector for dust removal. And the flue gas after dust removal enters a kiln tail chimney through a tail exhaust fan. The hot air at the outlet of the air preheater can be sent to a tertiary air pipe and enters the decomposing furnace as combustion-supporting air. Or can be sent to the inlet of the kiln tail SP waste heat boiler to increase the steam production of the kiln tail SP waste heat boiler. The steam can also be sent to the inlet of the kiln head AQC waste heat boiler, so that the steam production of the kiln head AQC boiler is increased.
The invention has the following beneficial effects:
1. the first-level quenching device adopts a volute structure or a sleeve structure, a cooling isolation layer is formed between hot flue gas and the wall surface of the device, the problem that dust in bypass air-bleeding flue gas is easy to adhere and block on the wall surface can be effectively solved, and the good and stable operation of the system is ensured.
2. And the waste heat in the bypass air-bleed waste gas is fully utilized through an air preheater. Hot air generated by the air preheater can be sent into a tertiary air pipe and then enters the decomposing furnace to be used as combustion-supporting air, so that the tertiary air quantity extracted by the kiln head grate cooler is correspondingly reduced, the zero pressure surface of the grate cooler moves forwards, the increase of the heat quantity of flue gas entering the kiln head boiler is influenced, and the steam production quantity of the kiln head boiler is correspondingly increased; hot air generated by the air preheater can be sent to an inlet of the kiln tail SP boiler, so that the steam production of the kiln tail SP boiler can be increased; hot air generated by the air preheater can also be sent to the inlet of the kiln head AQC boiler, so that the steam production of the kiln head AQC boiler can be increased; by the method, the power generated by the waste heat of the cement kiln can be effectively improved by about 5-30%.
3. Partial flue gas rich in harmful components such as potassium, sodium, chlorine and sulfur is discharged from the kiln tail smoke chamber through the system, and then a part of tertiary air is supplemented through the air preheater, so that the oxygen content of the flue gas in the decomposing furnace is improved, and the effects of improving the combustion condition of the kiln system, improving the coal combustion efficiency and reducing the coal consumption are achieved.
4. The high-temperature and high-alkali flue gas is cooled by the air preheater, so that the cooling air volume doped in the system can be effectively reduced, the capacities of the dust collector and the tail exhaust fan are greatly reduced, and the total cost of the bypass air discharge comprehensive utilization system is reduced.
5. The tail smoke chamber of the cement kiln is an enrichment part with the maximum concentration of NOx, an air discharge port is arranged at the enrichment part to discharge part of high-temperature kiln gas, and the temperature of the part of high-temperature kiln gas is reduced to 850-1050 ℃ after the part of high-temperature kiln gas is mixed with air by a primary quenching device. At this temperature, adopt SNCR denitration technology, the chemical reaction that takes place that aqueous ammonia and high concentration NOx can be more abundant, and the denitration effect is better, the improvement of phase-change like this system denitration efficiency. Compared with ammonia water used before bypass air release, the ammonia water used by the system and the process can be reduced, and the running cost of the system can be saved by about 10% under the condition of meeting the environmental protection requirement. By applying the system and the process, the concentration of NOx in the system can be reduced from 1500mg/m3 to 320mg/m3, and the national emission standard requirement is met.
6. After harmful components such as R +, Cl-, S and the like in the system are discharged by the method, the alkali content in the system is reduced, so that the requirement of production enterprises for producing low-alkali cement is met.
Drawings
FIG. 1 is a process system diagram I of the present invention
FIG. 2 is a schematic diagram II of a process system of the present invention
FIG. 3 is a schematic view of a process system of the present invention III
FIG. 4 is a schematic structural view of a spiral case type primary quenching device
FIG. 5 is a schematic structural view of a bushing type primary quenching device
Labeled as: kiln tail smoke chamber 1, primary quenching device 2, primary quenching fan 3, secondary air mixing device 4, secondary air mixing fan 5, air preheater 6, air blower 7, dust collector 8, tail exhaust fan 9, kiln tail chimney 10, tertiary air pipe 11, kiln tail SP boiler 12, kiln head AQC boiler 13, SNCR denitrification facility 14, cooling air inlet 15, outer sleeve 16, inner sleeve 17, flue gas inlet 18, flue gas outlet 19
Detailed Description
The following is further described with reference to the accompanying drawings.
The text is first briefly explained as follows:
SNCR: selective Non-Catalytic Reduction, a denitration technique, i.e. Selective Non-Catalytic Reduction;
AQC: air Quenching Cooler, grate Cooler;
SP: suspension Preheater, Suspension Preheater.
As shown in fig. 1, a kiln tail smoke chamber, a primary quenching device, an SNCR denitration device, a secondary air mixing device, an air preheater, a dust collector, a tail exhaust fan and a kiln tail chimney are sequentially connected through a flue. Wherein, the cooling air inlet of the primary quenching device is connected with the outlet of the primary quenching fan, and the inlet of the primary quenching fan is connected with air; a cooling air inlet of the secondary air mixing device is connected with an outlet of a secondary air mixing fan, and an inlet of the secondary air mixing fan is connected with air; the air inlet of the air preheater is connected with the outlet of the air blower, and the air outlet of the air preheater is connected with the tertiary air pipe.
In the system, thermocouples are respectively arranged at a smoke outlet of the primary quenching device, a smoke outlet of the secondary air mixing device, a hot air outlet of the air preheater and a hot smoke outlet of the air preheater and are used for detecting the temperature of a medium.
A valve for controlling air quantity is arranged on a connecting air pipe of the primary quenching device and the primary quenching fan; the second-stage air mixing device is connected with the second-stage air mixing fan, and an air pipe is provided with a valve for controlling air quantity; the air inlet of the air preheater and the air blower are connected with an air pipe, valves for controlling air quantity are arranged on the air pipe, and the flow of the medium is adjusted by controlling the opening of the valves.
The specific working process is as follows: an air discharge port is arranged at the enrichment part of the tail smoke chamber R +, Cl-S, NOx of the cement kiln, part of high-temperature smoke with high R +, Cl-S, NOx content and the temperature of 1200 ℃ is extracted through a bypass air intake flue, and the high-temperature smoke enters a primary quenching device through a flue and is mixed and cooled with cold air from the outlet of a primary quenching fan. The temperature of the flue gas cooled by the primary quenching device is reduced to 500-1100 ℃, and the cooling air quantity entering the primary quenching device is adjusted by adjusting the opening degree of a valve on an air pipe connected with the primary quenching device and a primary quenching fan, so that the temperature of the cooled flue gas is optimally 850-1050 ℃. The flue gas then enters an SNCR denitration device to remove NOx in the flue gas. The denitrated flue gas enters a secondary air mixing device, is fully mixed with cold air at the outlet of a secondary air mixing fan and is cooled to 300-950 ℃, and the cooling air quantity entering the secondary air mixing device is adjusted by adjusting the opening degree of a valve on an air pipe connecting the secondary air mixing device and the secondary air mixing fan, so that the temperature of the cooled flue gas is optimal to 650 ℃. The hot flue gas cooled by the secondary air mixing device enters an air preheater, and exchanges heat with cold air input by an air blower through a heat exchange surface of the air preheater, the temperature of the air is increased to 200-800 ℃ after heat exchange, and the temperature of the flue gas after heat exchange is reduced to 100-360 ℃. The opening degree of a valve on an air inlet of the air preheater and an air pipe connected with a blower is adjusted, and the amount of cold air input into the air preheater is adjusted, so that the outlet temperature of hot air after heat exchange of the air preheater is optimally 450-550 ℃, and the temperature of outlet flue gas after heat exchange of the air preheater is optimally 160 ℃. Then the flue gas enters a dust collector for dust removal. And the flue gas after dust removal enters a kiln tail chimney through a tail exhaust fan. The hot air at the outlet of the air preheater can be sent to a tertiary air pipe and enters the decomposing furnace as combustion-supporting air.
As shown in fig. 2, a kiln tail smoke chamber, a primary quenching device, an SNCR denitration device, a secondary air mixing device, an air preheater, a dust collector, a tail exhaust fan and a kiln tail chimney are sequentially connected through a flue. Wherein, the cooling air inlet of the primary quenching device is connected with the outlet of the primary quenching fan, and the inlet of the primary quenching fan is connected with air; a cooling air inlet of the secondary air mixing device is connected with an outlet of a secondary air mixing fan, and an inlet of the secondary air mixing fan is connected with air; and an air inlet of the air preheater is connected with an outlet of the air blower, and an air outlet of the air preheater is connected with an inlet of the SP waste heat boiler at the kiln tail.
In the system, thermocouples are respectively arranged at a smoke outlet of the primary quenching device, a smoke outlet of the secondary air mixing device, a hot air outlet of the air preheater and a hot smoke outlet of the air preheater and are used for detecting the temperature of a medium.
A valve for controlling air quantity is arranged on a connecting air pipe of the primary quenching device and the primary quenching fan; the second-stage air mixing device is connected with the second-stage air mixing fan, and an air pipe is provided with a valve for controlling air quantity; the air inlet of the air preheater and the air blower are connected with an air pipe, valves for controlling air quantity are arranged on the air pipe, and the flow of the medium is adjusted by controlling the opening of the valves.
The specific working process is as follows: an air discharge port is arranged at the enrichment part of the tail smoke chamber R +, Cl-S, NOx of the cement kiln, part of high-temperature smoke with high R +, Cl-S, NOx content and the temperature of 1200 ℃ is extracted through a bypass air intake flue, and the high-temperature smoke enters a primary quenching device through a flue and is mixed and cooled with cold air from the outlet of a primary quenching fan. The temperature of the flue gas cooled by the primary quenching device is reduced to 500-1100 ℃, and the cooling air quantity entering the primary quenching device is adjusted by adjusting the opening degree of a valve on an air pipe connected with the primary quenching device and a primary quenching fan, so that the temperature of the cooled flue gas is optimally 850-1050 ℃. The flue gas then enters an SNCR denitration device to remove NOx in the flue gas. The denitrated flue gas enters a secondary air mixing device, is fully mixed with cold air at the outlet of a secondary air mixing fan and is cooled to 300-950 ℃, and the cooling air quantity entering the secondary air mixing device is adjusted by adjusting the opening degree of a valve on an air pipe connecting the secondary air mixing device and the secondary air mixing fan, so that the temperature of the cooled flue gas is optimal to 650 ℃. The hot flue gas cooled by the secondary air mixing device enters an air preheater, and exchanges heat with cold air input by an air blower through a heat exchange surface of the air preheater, the temperature of the air is increased to 200-800 ℃ after heat exchange, and the temperature of the flue gas after heat exchange is reduced to 100-360 ℃. The opening degree of a valve on an air inlet of the air preheater and an air pipe connected with a blower is adjusted, and the amount of cold air input into the air preheater is adjusted, so that the outlet temperature of hot air after heat exchange of the air preheater is optimally 450-550 ℃, and the temperature of outlet flue gas after heat exchange of the air preheater is optimally 160 ℃. Then the flue gas enters a dust collector for dust removal. And the flue gas after dust removal enters a kiln tail chimney through a tail exhaust fan. The hot air at the outlet of the air preheater can be sent to the inlet of the kiln tail SP waste heat boiler, so that the steam production of the kiln tail SP waste heat boiler is increased.
As shown in fig. 3, the kiln tail smoke chamber, the primary quenching device, the SNCR denitration device, the secondary air mixing device, the air preheater, the dust collector, the tail exhaust fan and the kiln tail chimney are sequentially connected through a flue. Wherein, the cooling air inlet of the primary quenching device is connected with the outlet of the primary quenching fan, and the inlet of the primary quenching fan is connected with air; a cooling air inlet of the secondary air mixing device is connected with an outlet of a secondary air mixing fan, and an inlet of the secondary air mixing fan is connected with air; an air inlet of the air preheater is connected with an outlet of the air blower, and an air outlet of the air preheater is connected with an inlet of the kiln head AQC waste heat boiler.
In the system, thermocouples are respectively arranged at a smoke outlet of the primary quenching device, a smoke outlet of the secondary air mixing device, a hot air outlet of the air preheater and a hot smoke outlet of the air preheater and are used for detecting the temperature of a medium.
A valve for controlling air quantity is arranged on a connecting air pipe of the primary quenching device and the primary quenching fan; the second-stage air mixing device is connected with the second-stage air mixing fan, and an air pipe is provided with a valve for controlling air quantity; the air inlet of the air preheater and the air blower are connected with an air pipe, valves for controlling air quantity are arranged on the air pipe, and the flow of the medium is adjusted by controlling the opening of the valves.
The specific working process is as follows: an air discharge port is arranged at the enrichment part of the tail smoke chamber R +, Cl-S, NOx of the cement kiln, part of high-temperature smoke with high R +, Cl-S, NOx content and the temperature of 1200 ℃ is extracted through a bypass air intake flue, and the high-temperature smoke enters a primary quenching device through a flue and is mixed and cooled with cold air from the outlet of a primary quenching fan. The temperature of the flue gas cooled by the primary quenching device is reduced to 500-1100 ℃, and the cooling air quantity entering the primary quenching device is adjusted by adjusting the opening degree of a valve on an air pipe connected with the primary quenching device and a primary quenching fan, so that the temperature of the cooled flue gas is optimally 850-1050 ℃. The flue gas then enters an SNCR denitration device to remove NOx in the flue gas. The denitrated flue gas enters a secondary air mixing device, is fully mixed with cold air at the outlet of a secondary air mixing fan and is cooled to 300-950 ℃, and the cooling air quantity entering the secondary air mixing device is adjusted by adjusting the opening degree of a valve on an air pipe connecting the secondary air mixing device and the secondary air mixing fan, so that the temperature of the cooled flue gas is optimal to 650 ℃. The hot flue gas cooled by the secondary air mixing device enters an air preheater, and exchanges heat with cold air input by an air blower through a heat exchange surface of the air preheater, the temperature of the air is increased to 200-800 ℃ after heat exchange, and the temperature of the flue gas after heat exchange is reduced to 100-360 ℃. The opening degree of a valve on an air inlet of the air preheater and an air pipe connected with a blower is adjusted, and the amount of cold air input into the air preheater is adjusted, so that the outlet temperature of hot air after heat exchange of the air preheater is optimally 450-550 ℃, and the temperature of outlet flue gas after heat exchange of the air preheater is optimally 160 ℃. Then the flue gas enters a dust collector for dust removal. And the flue gas after dust removal enters a kiln tail chimney through a tail exhaust fan. The hot air at the outlet of the air preheater can be sent to the inlet of the kiln head AQC waste heat boiler, so that the steam production of the kiln head AQC waste heat boiler is increased.
As shown in FIG. 4, the first-stage quenching device is a cylindrical structure, two ends of the cylinder are connected with a flue gas pipeline, and a cooling air inlet is arranged at the tangential position of the side surface of the cylinder. The cooling air entering the cylinder through the cooling air tangential inlet rotates on the inner wall of the cylinder due to the inertia effect, so that a cooling layer is formed on the inner wall of the cylinder and completely wraps the hot flue gas, and the blockage caused by the adhesion of sticky dust in the high-temperature flue gas on the inner wall surface of the primary quenching device is fundamentally prevented.
As shown in fig. 5, the primary quenching device is composed of two concentric sleeves inside and outside, and the end of each sleeve is provided with an end plate, so that a closed cavity is formed between the two sleeves; wherein, interior sleeve pipe both ends are connected with flue gas pipeline, offer a plurality of holes on the interior sleeve pipe circumference wall, and the outer tube pipe wall is equipped with the cooling air entry. Because the cooling air radially enters the inner sleeve through the small holes on the wall surface of the inner sleeve, certain air pressure is generated, and dust is prevented from being adhered and blocked on the wall surface. Simultaneously, hot flue gas can mix with cooling air fast, the effectual temperature that reduces the flue gas.
Claims (8)
1. The utility model provides a cement kiln bypass is let out wind energy saving and emission reduction and is used multipurposely system and technology, includes kiln tail smoke chamber, one-level rapid cooling device, one-level rapid cooling fan, SNCR denitrification facility, second grade mix wind device, second grade mix wind fan, air heater, air-blower, dust collector, tail exhaust fan, kiln tail chimney, hot-blast operative installations, its characterized in that: the kiln tail smoke chamber, the primary quenching device, the SNCR denitration device, the secondary air mixing device, the air preheater, the dust collector, the tail exhaust fan and the kiln tail chimney are sequentially connected through a flue, a cooling air inlet of the primary quenching device is connected with an outlet of the primary quenching fan, and an inlet of the primary quenching fan is connected with air; a cooling air inlet of the secondary air mixing device is connected with an outlet of a secondary air mixing fan, and an inlet of the secondary air mixing fan is connected with air; the air inlet of the air preheater is connected with the outlet of the air blower, and the air outlet of the air preheater is connected with the inlet of the hot air using device.
2. The cement kiln bypass air-bleeding energy-saving emission-reducing comprehensive utilization system and process as claimed in claim 1, characterized in that: the hot air using device is a tertiary air pipe or a kiln tail SP waste heat boiler or a kiln head AQC waste heat boiler.
3. The cement kiln bypass air-bleeding energy-saving emission-reducing comprehensive utilization system and process as claimed in claim 2, characterized in that: the flue gas outlet of the primary quenching device, the flue gas outlet of the secondary air mixing device, the hot air outlet of the air preheater and the hot flue gas outlet of the air preheater are respectively provided with a thermocouple.
4. The cement kiln bypass air-bleeding energy-saving emission-reducing comprehensive utilization system and process as claimed in claim 2, characterized in that: the primary quenching device is connected with a primary quenching fan and is provided with a valve for controlling air quantity; the secondary air mixing device and the secondary air mixing fan are connected with an air pipe, and a valve for controlling air quantity is arranged on the air pipe; and a valve for controlling the air quantity is arranged on the air inlet of the air preheater and the air blower connecting air pipe.
5. The cement kiln bypass air-bleeding energy-saving emission-reducing comprehensive utilization system and process as claimed in claim 2, characterized in that: the first-stage quenching device adopts a volute structure or a sleeve structure.
6. The cement kiln bypass air-bleeding energy-saving emission-reducing comprehensive utilization system and process as claimed in claim 5, wherein: the first-stage quenching device of the volute structure is cylindrical, two ends of the cylinder are connected with a flue gas pipeline, and a cooling air inlet is arranged at the tangential position of the side surface of the cylinder.
7. The cement kiln bypass air-bleeding energy-saving emission-reducing comprehensive utilization system and process as claimed in claim 5, wherein: the primary quenching device of the sleeve structure is composed of two concentric sleeves inside and outside, and the end part of each sleeve is provided with an end plate, so that a closed cavity is formed between the two sleeves; wherein, interior sleeve pipe both ends are connected with flue gas pipeline, offer a plurality of holes on the interior sleeve pipe circumference wall, and the outer tube pipe wall is equipped with the cooling air entry.
8. The cement kiln bypass air-bleeding energy-saving emission-reducing comprehensive utilization system and process as claimed in any one of claims 1 to 4, characterized in that: the temperature of the smoke outlet of the first-stage quenching device is 500-1100 ℃, the temperature of the smoke outlet of the second-stage air mixing device is 300-950 ℃, the temperature of the hot air outlet of the air preheater is 200-800 ℃, and the temperature of the hot smoke outlet of the air preheater is 100-360 ℃.
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| CN104048297A (en) * | 2014-06-23 | 2014-09-17 | 杨义军 | Cement kiln cooperative processing combustible waste and by-pass exhaust power generation complementary system |
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