CN114642957A - Combined denitration device and denitration method for industrial gas-fired boiler - Google Patents
Combined denitration device and denitration method for industrial gas-fired boiler Download PDFInfo
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- 238000000034 method Methods 0.000 title claims abstract description 40
- 238000005507 spraying Methods 0.000 claims abstract description 105
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 claims abstract description 83
- 235000011114 ammonium hydroxide Nutrition 0.000 claims abstract description 83
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 claims abstract description 63
- 239000003546 flue gas Substances 0.000 claims abstract description 63
- 239000007921 spray Substances 0.000 claims abstract description 63
- 239000007789 gas Substances 0.000 claims abstract description 39
- 230000007246 mechanism Effects 0.000 claims abstract description 26
- QGZKDVFQNNGYKY-UHFFFAOYSA-N ammonia Natural products N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 claims abstract description 17
- 238000006722 reduction reaction Methods 0.000 claims abstract description 4
- 239000000428 dust Substances 0.000 claims description 23
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 21
- 239000003054 catalyst Substances 0.000 claims description 14
- 239000000203 mixture Substances 0.000 claims description 9
- 238000007865 diluting Methods 0.000 claims description 7
- 239000012717 electrostatic precipitator Substances 0.000 claims description 6
- 230000009471 action Effects 0.000 claims description 3
- 238000004364 calculation method Methods 0.000 claims description 3
- 238000001816 cooling Methods 0.000 claims description 3
- 238000007599 discharging Methods 0.000 claims description 3
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 abstract description 2
- 238000006243 chemical reaction Methods 0.000 abstract description 2
- 239000001301 oxygen Substances 0.000 abstract description 2
- 229910052760 oxygen Inorganic materials 0.000 abstract description 2
- 238000012544 monitoring process Methods 0.000 abstract 1
- 230000011664 signaling Effects 0.000 abstract 1
- 230000008569 process Effects 0.000 description 11
- MWUXSHHQAYIFBG-UHFFFAOYSA-N Nitric oxide Chemical compound O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 description 6
- 230000006872 improvement Effects 0.000 description 6
- 238000004519 manufacturing process Methods 0.000 description 5
- 229910021529 ammonia Inorganic materials 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 239000000446 fuel Substances 0.000 description 4
- 239000003245 coal Substances 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 239000002994 raw material Substances 0.000 description 3
- 230000009286 beneficial effect Effects 0.000 description 2
- 238000010531 catalytic reduction reaction Methods 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 230000001276 controlling effect Effects 0.000 description 2
- 238000010790 dilution Methods 0.000 description 2
- 239000012895 dilution Substances 0.000 description 2
- 230000005684 electric field Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 238000009434 installation Methods 0.000 description 2
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 210000003437 trachea Anatomy 0.000 description 2
- 239000002918 waste heat Substances 0.000 description 2
- 241000894006 Bacteria Species 0.000 description 1
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 description 1
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Chemical compound NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 description 1
- 244000052616 bacterial pathogen Species 0.000 description 1
- 239000004202 carbamide Substances 0.000 description 1
- 230000003197 catalytic effect Effects 0.000 description 1
- 239000003638 chemical reducing agent Substances 0.000 description 1
- 239000000571 coke Substances 0.000 description 1
- 238000006477 desulfuration reaction Methods 0.000 description 1
- 230000023556 desulfurization Effects 0.000 description 1
- 229910001882 dioxygen Inorganic materials 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 239000002737 fuel gas Substances 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 239000003345 natural gas Substances 0.000 description 1
- IJGRMHOSHXDMSA-UHFFFAOYSA-N nitrogen Substances N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 230000001012 protector Effects 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 239000000779 smoke Substances 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 238000009423 ventilation Methods 0.000 description 1
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
- B01D53/86—Catalytic processes
- B01D53/8621—Removing nitrogen compounds
- B01D53/8625—Nitrogen oxides
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/46—Removing components of defined structure
- B01D53/54—Nitrogen compounds
- B01D53/56—Nitrogen oxides
-
- 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
- B01D53/77—Liquid phase processes
- B01D53/78—Liquid phase processes with gas-liquid contact
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Environmental & Geological Engineering (AREA)
- Health & Medical Sciences (AREA)
- Biomedical Technology (AREA)
- Analytical Chemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Chimneys And Flues (AREA)
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Abstract
The invention discloses a combined denitration device and a denitration method for an industrial gas boiler. An industrial gas boiler combined denitration device comprises an SNCR denitration mechanism; the SNCR denitration mechanism includes: a storage tank for storing ammonia water; a pressurizing pump for pressurizing the ammonia water; a distributor for distributing ammonia water; an air compressor for compressing air; a plurality of spray guns for spraying ammonia water and compressed air; a plurality of temperature sensors for monitoring the furnace temperature; and a controller for receiving the signal and controlling the spraying of the ammonia water and the compressed air. Compared with the existing denitration device of the industrial gas boiler: this device passes through temperature sensor and gathers the temperature signal in the furnace different regions, and the controller receives temperature signal and handles to control the spray gun and spray aqueous ammonia and compressed air to corresponding region, can improve the area of contact of flue gas and aqueous ammonia, oxygen reaction effectively, fully carry out reduction reaction, thereby improve flue gas denitration's efficiency.
Description
Technical Field
The invention relates to the technical field of flue gas treatment of industrial gas boilers, in particular to a combined denitration device and a denitration method for an industrial gas boiler.
Background
Industrial gas boilers are common devices in factories and enterprises, and boilers use fuels such as natural gas, blast furnace gas, coke oven gas, and the like, and heat desalted water and softened water to generate hot water or steam for production and life of the enterprises. Along with the strict requirements of environmental protection and the requirements of protecting the ecological environment, the boiler flue gas is discharged after reaching the standard after being subjected to desulfurization, denitration and dust removal treatment.
The industrial boiler has the characteristics of low temperature of a tail flue, high load adjusting frequency and the like. When the flue gas is denitrated by using a Selective Catalytic Reduction (SCR) high-temperature denitration catalyst, the denitration effect can be achieved only by adjusting the flue gas temperature to be within the range of the catalyst active temperature. The waste heat of the flue gas is recovered by a coal economizer after the temperature of the flue gas is increased. Or the SCR denitration catalyst is installed at the high-temperature section of the boiler, and the installation of the SCR denitration catalyst at the high-temperature section of the boiler is very inconvenient in the integrated equipment of the industrial boiler. The low-temperature denitration catalyst is arranged in front of the economizer, so that the denitration requirement can be met. The SNCR (selective non-catalytic reduction) denitration process has relatively few equipment and convenient installation, but has higher requirement on the temperature range of flue gas, and the denitration efficiency is greatly reduced outside the temperature range. The load of the industrial boiler is adjusted along with the change of production, so that the gas quantity, the flame temperature and the flame length are changed, and the temperature range suitable for the SNCR denitration process is unfixed. Even if the temperature range is proper, the flue gas in the hearth cannot be covered by directly spraying a reducing agent (such as ammonia water, urea and the like) in the SNCR denitration process, so that the denitration efficiency is not particularly ideal.
Disclosure of Invention
The invention provides a combined denitration device and a denitration method for an industrial gas boiler, aiming at solving the problem that the denitration efficiency of the existing industrial gas boiler is not particularly ideal.
The invention is realized by adopting the following technical scheme: a combined denitration device of an industrial gas boiler; the device comprises an SNCR denitration mechanism; the SNCR denitration mechanism includes:
the storage tank is used for storing ammonia water;
a pressurizing pump, one end of which is communicated with the storage tank and used for pressurizing the ammonia water;
the distributor comprises an input end and a plurality of output ends formed by distributing the input end, and the input end is communicated with an outlet at the other end of the pressure pump; and
the spray guns are respectively communicated with the output ends and are used for spraying ammonia water to different areas in a hearth of the boiler;
characterized in that, SNCR denitration mechanism still includes:
the air compressor comprises a plurality of air outlets which are respectively communicated with the plurality of spray guns; the ammonia water distributed by the distributor is mixed with the compressed air output by the air compressor and then sprayed by a corresponding spray gun;
the first electric control valves are respectively arranged on pipelines between the output ends and the corresponding spray guns;
the second electric control valves are respectively arranged on pipelines between the gas outlets and the corresponding spray guns;
the temperature sensors are used for respectively detecting the temperatures of different areas in the hearth; and
the controller judges whether each temperature is between 850 and 1100 ℃, and counts the number of the areas with the temperature between 850 and 1100 ℃; spraying the area with the temperature of 850-1100 ℃ by starting the first electric control valve and the second electric control valve in the corresponding areas; the non-spraying to other areas is realized by closing the first electric control valve and the second electric control valve in the corresponding areas; when the number of the areas with the temperature of 850-1100 ℃ is increased, the number of the spray guns in the spraying state is increased, and the spraying rate of each spray gun in the spraying state is reduced, so that the total spraying rate is kept unchanged; when the number of the areas with the temperature between 850 ℃ and 1100 ℃ is reduced, the number of the spray guns in the spraying state is reduced, and the spraying speed of each spray gun in the spraying state is increased, so that the total spraying speed is kept unchanged.
The temperature sensor collects temperature signals of different areas in the boiler furnace and transmits the temperature signals to the controller. The controller processes the temperature signal and controls the switches of the first electric control valve and the second electric control valve, so that the spray gun is controlled to spray the ammonia water and the compressed air into the corresponding temperature area. The ammonia water from the storage tank is pressurized by the pressurizing pump and then transmitted to the distributor, the distributor uniformly distributes the ammonia water and then transmits the ammonia water to the spray gun, meanwhile, the air compressor compresses air and then respectively transmits the compressed air to the spray gun, the compressed air is mixed with the ammonia water and atomizes the ammonia water, the mixture of the atomized ammonia water and the compressed air is sprayed into a corresponding temperature area of the hearth through the spray gun, and when the ammonia water flows into the spray gun from the distributor, the flow meter monitors the spraying amount and the spraying speed of the ammonia water. The controller controls the input amount and the spraying speed of the spray gun according to the temperatures of different areas in the hearth and the flow of the ammonia water monitored by the flow meter, so that the ammonia water and the compressed air are sprayed into the optimal temperature area, the flue gas is fully reacted, and the efficiency of the SNCR denitration process is improved.
As a further improvement of the scheme, a coal economizer is arranged on the outer side of the boiler, and one end of the coal economizer is communicated with the hearth and used for absorbing heat of the flue gas.
As the further improvement of above-mentioned scheme, industry gas boiler combination denitrification facility still is provided with dust removal mechanism, and dust removal mechanism includes: one end of the filter is communicated with the other end of the economizer, and a plurality of layers of filter screens are arranged in the filter; and one end of the electrostatic dust collector is communicated with the other end of the filter.
As the further improvement of above-mentioned scheme, industry gas boiler combination denitrification facility still includes SCR denitration mechanism, and SCR denitration mechanism includes: one end of the first air pipe is communicated with the other end of the electrostatic dust collector; a plurality of second air pipes connected to the other end of the first air pipe in sequence; the plurality of electric control valves IV are respectively arranged on the plurality of second air pipes; the SCR reactors are respectively communicated with the second air pipes; and a plurality of catalysts respectively arranged in the SCR reactors
As a further improvement of the scheme, the combined denitration device of the industrial gas-fired boiler further comprises an exhaust mechanism, and the exhaust mechanism comprises: the tail flue is communicated with the SCR reactors at one end; and the chimney is communicated with the other end of the tail flue and is used for discharging the denitrated flue gas into the air.
An industrial gas boiler combined denitration device comprises an SNCR denitration mechanism; the SNCR denitration mechanism includes:
the storage tank is used for storing ammonia water;
one end of the pressure pump is communicated with the storage tank;
the distributor comprises an input end and a plurality of output ends formed by distributing the input end, and the input end is communicated with an outlet at the other end of the pressure pump; and
the spray guns are respectively communicated with the output ends and are used for spraying ammonia water to different areas in a hearth of the boiler;
characterized in that, SNCR denitration mechanism still includes:
one end of the atomizer is communicated with the other end of the pressure pump;
the three-way pipe comprises two inlets and an outlet, wherein one inlet is connected with the other end of the atomizer; one of the outlets is communicated with the input end; and
the air compressor is communicated with the other inlet of the three-way pipe;
the first electric control valves are respectively arranged on pipelines between the output ends and the corresponding spray guns;
the electric control valve III is arranged on a pipeline between the air compressor and the corresponding inlet;
the flow meters are respectively arranged on the pipelines between the output ends and the corresponding spray guns;
the temperature sensors are used for respectively detecting the temperatures of different areas in the hearth; and
the controller judges whether each temperature is between 850 and 1100 ℃, and counts the number of the areas with the temperature between 850 and 1100 ℃; diluting ammonia water in the corresponding area by adopting water according to the average temperature; calculating the spraying speed of the spray guns in each area according to the average temperature and the number of the areas; and spraying a mixture of ammonia water and compressed air into the hearth according to the spraying speed.
The invention also provides a combined denitration method for the industrial gas boiler, which is applied to any combined denitration device for the industrial gas boiler and comprises an SNCR denitration method, and the SNCR denitration method is characterized by comprising the following steps of:
the first step is as follows: dividing a hearth into a plurality of regions with uniform sizes;
the second step is that: collecting the average temperature of different areas in a hearth;
the third step: finding out the area with the average temperature lower than 850 ℃, the area higher than 1100 ℃ and the area at 850-1100 ℃, and counting the corresponding area number;
the fourth step: spraying ammonia water and compressed air to the area with the temperature of 850-1100 ℃ by starting the first electric control valve and the second electric control valve of the corresponding area; the first electric control valve and the second electric control valve in the corresponding areas are closed to realize that other areas are not sprayed; and
the fifth step: when the number of the areas with the temperature of 850-1100 ℃ is increased, the number of the spray guns in the spraying state is increased, and the spraying rate of each spray gun in the spraying state is reduced, so that the total spraying rate is kept unchanged; when the number of the areas with the temperature between 850 ℃ and 1100 ℃ is reduced, the number of the spray guns in the spraying state is reduced, and the spraying speed of each spray gun in the spraying state is increased, so that the total spraying speed is kept unchanged.
The combined denitration method for the industrial gas boiler comprises an SNCR denitration method, and is characterized by comprising the following steps of:
the first step is as follows: dividing a hearth into a plurality of regions with uniform sizes;
the second step is that: collecting the average temperature of different areas in a hearth;
the third step: finding out the areas with the average temperature lower than 850 ℃, the areas higher than 1100 ℃ and the areas at 850-1100 ℃, and calculating the corresponding number of the areas;
the fourth step: diluting ammonia water in the corresponding area by adopting water according to the average temperature; the method for diluting the ammonia water comprises the following steps:
when the average temperature of all areas in the hearth is lower than 850 ℃, the mixing ratio of the ammonia water to the water is 1: 0;
when the average temperature of all areas in the hearth is higher than 1100 ℃, the mixing ratio of the ammonia water to the water is 1: 3; and
otherwise, the mixing ratio of the ammonia water to the water is 1: 1;
the fifth step: calculating the spraying speed of the spray guns in each area according to the average temperature and the number of the areas; the calculation method of the spraying rate comprises the following steps:
when the average temperature of all the areas in the hearth is lower than 850 ℃, spraying all the areas, wherein the corresponding spraying rates are as follows: p is S/N;
when the average temperature of all the zones in the furnace is higher than 1100 ℃, spraying all the zones, and the corresponding spraying rates are as follows: p is 4S/N;
otherwise, spraying is only performed on the area with the temperature of 850-: p is 2S/n; and
wherein P is the spraying rate in each zone, S is the target spraying rate, N is the number of all zones, and N is the number of zones with the temperature between 850-; and
and sixthly, spraying a mixture of ammonia water and compressed air into the hearth according to the spraying rate.
As a further improvement of the two schemes, the combined denitration method for the industrial gas-fired boiler further comprises the following steps:
cooling the flue gas, which comprises absorbing the heat of the flue gas by using an economizer and reducing the temperature of the flue gas to between 200 ℃ and 400 ℃;
dedusting the flue gas, which comprises the following steps: performing primary dust removal on the flue gas by using a filter; carrying out secondary dust removal on the flue gas by using an electrostatic dust remover;
SCR denitration, which comprises the following steps: introducing the dedusted flue gas into a plurality of SCR reactors respectively; the flue gas is subjected to reduction reaction with residual ammonia gas and air under the action of a catalyst; and
the method comprises the following steps of: and introducing the denitrated flue gas into a chimney through a tail flue, and discharging the flue gas into the air through a discharge port of the chimney.
Compared with the existing denitration device for the industrial gas boiler, the combined denitration device for the industrial gas boiler and the denitration method thereof have the following beneficial effects:
1. temperature signals of different areas in a boiler furnace are collected through a temperature sensor, a controller receives the temperature signals and processes the temperature signals, so that a first electric control valve and a second electric control valve of the corresponding area are controlled to be opened or closed, ammonia water and compressed air are sprayed to the area with the temperature between 850 and 1100 ℃, the total spraying speed is controlled to be kept unchanged, smoke is fully combined with the ammonia water and the compressed air in the area between 850 and 1100 ℃, and the denitration efficiency is improved.
2. The economizer absorbs heat in the flue gas and is repeatedly used for heating the boiler, so that heat loss is avoided, the input amount of fuel gas can be reduced, the cost is saved, a low-temperature environment is provided for SCR denitration, and the operation cost of SCR denitration is reduced;
3. dust, bacteria and the like in the flue gas are removed through twice dust removal of the filter and the electrostatic dust collector, so that the loss of the dust to a catalyst in the SCR denitration process is reduced, the operation cost is reduced, and the pollution of the flue gas emission to the air is reduced;
4. the multiple SCR reactors receive the flue gas subjected to cooling and dedusting after primary denitration, respectively perform secondary denitration of the SCR process, can repeatedly utilize the waste heat of the flue gas and the ammonia gas, oxygen gas and the like remaining after the primary denitration, reduce the input and the conveying of raw materials required by the secondary denitration, and save the cost
5. The flue gas is discharged into the air through the tail flue and the chimney, so that the influence on the production environment is avoided, and the safety risk is reduced.
6. The beneficial effects of the combined denitration method for the industrial gas boiler are the same as those of the combined denitration device for the industrial gas boiler, and are not repeated herein.
Drawings
FIG. 1 is a schematic structural diagram of a combined denitration apparatus according to example 1 of the present invention;
FIG. 2 is a schematic structural diagram of a combined denitration apparatus according to example 2 of the present invention;
fig. 3 is a flowchart of the SNCR denitration process of example 3 of the present invention.
Description of the symbols:
1 controller 2 burner
3 temperature sensor 5 reservoir
7 pressure pump 9 atomizer
11 three-way pipe 13 air compressor
17 ammonia water distributor 18 valve one
20 valve two 21 spray gun
22 valve three 23 economizer
25 filter 27 filter screen
29 first pipe of electrostatic precipitator 31
33 second conduit 35 valve four
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
Example 1
Please refer to fig. 1, which is a schematic structural diagram of the combined denitration device of the present embodiment. The combined denitration device of the industrial gas boiler comprises an SNCR denitration mechanism; the SNCR denitration mechanism includes a controller 1, a temperature sensor 3, a storage tank 5, a pressurizing pump 7, a distributor 17, a plurality of spray guns 21, and an air compressor 13.
One end of the pressure pump 7 is communicated with the storage tank 5, the other end of the pressure pump is communicated with the distributor 17, the pressure pump 7 pressurizes ammonia water and then conveys the ammonia water into the distributor 17, and the distributor 17 uniformly distributes the input ammonia water and then conveys the ammonia water into the spray gun 21 from a plurality of output ends. Meanwhile, the air compressor 13 pressurizes air and then uniformly conveys the air into the spray gun 21, so that the compressed air is mixed with ammonia water and atomizes the ammonia water, and then the atomized ammonia water and the compressed air are sprayed into the hearth through the spray gun 21.
A flow meter 16 and an electric control valve 18 are respectively arranged between a plurality of output ends of the distributor 17 and the plurality of spray guns, a plurality of electric control valves 20 are respectively arranged between the air compressor 13 and the plurality of spray guns, and the electric control valves 20 can control the spraying of compressed air on corresponding pipelines. The flow meter 16, the first electric control valve 18 and the second electric control valve 20 are respectively connected with a controller, the controller is further remotely connected with the plurality of temperature sensors 3, the controller 1 receives temperature signals detected by the temperature sensors 3 and ammonia water flow signals monitored by the flow meter, judges whether the temperature of each area is between 850 ℃ and 1100 ℃, counts the number of the areas, judges the area to be sprayed and the spraying rate of the area to be sprayed, then controls the switches of the first electric control valve 18 and the first electric control valve 20, sprays a mixture of atomized ammonia water and compressed air to the corresponding areas, and keeps the total spraying rate unchanged.
The flue gas is fully combined with atomized ammonia water and air in the region with the temperature of 850-.
The outer side of the boiler is provided with a burner 2 matched with the boiler, the burner 2 is a low-nitrogen burner, fuel of the burner is combustible gas, the burner 2 comprises a gas pipeline, an igniter, a flameout protector, a ventilation pipeline and an air regulator, when the burner 2 operates, a large amount of high-temperature flue gas can be generated, the flue gas contains nitrogen oxide exceeding the emission standard, so that the flue gas needs to be subjected to denitration and then is discharged, and the air regulator can control not only the air inlet amount and the air inlet direction, but also the air amount required by the fuel, so that the output temperature of the burner can be regulated, and the temperature of the flue gas in a hearth is controlled to be 850-.
The flue gas flows into the economizer 23 after the denitration of SNCR technology once, and the economizer can absorb the heat in the flue gas, improves the efficiency of boiler heating to reduce the input of fuel, reduce the temperature of flue gas simultaneously, be convenient for carry out the SCR denitration.
The outlet of the economizer 23 is communicated with one end of the filter 25, the other end of the filter 25 is communicated with the electrostatic precipitator 29, the flue gas is filtered by the multi-layer filter screen 27 to remove dust with larger particles, when the filtered flue gas passes through the electrostatic precipitator 29, the flue gas is ionized by using a high-voltage electric field emitted by the electrostatic precipitator 29, and the charged dust in the air flow is separated from the air flow under the action of the electric field, so that the dust and germs with smaller particles in the flue gas are removed.
The flue gas after dust removal evenly shunts to second trachea 33 behind first trachea 31, flows into a plurality of SCR reactors respectively afterwards, and remaining nitrogen oxide in the flue gas mixes with ammonia, oxygen, continues to take place reduction reaction under the effect of catalyst 39, accomplishes the secondary denitration.
The SCR denitration technology of this device need not to drop into the raw materials from the external world, also need not to build low temperature environment from the external world, has reduced the running cost of SCR denitration effectively, and the flue gas after the dust removal avoids on adhering to the catalyst simultaneously, reduces the wearing and tearing of catalyst, improves the catalytic effect of catalyst.
The flue gas after the secondary denitration reaches the emission standard, and the flue gas is guided into a chimney 43 through a tail flue 41 and then is discharged into the air.
The flue gas temperature after secondary denitration still exceeds 50 ℃, and direct emission can cause the influence to the production environment, even produce the personal danger, and it can reduce the safety risk to discharge it aloft.
Example 2
Referring to fig. 2, the embodiment provides an industrial gas boiler combined denitration device, compared with the first embodiment:
one end of the pressure pump 7 is communicated with the storage tank 5, the other end of the pressure pump is communicated with the atomizer 9, the atomizer 9 atomizes the pressurized ammonia water and then conveys the atomized ammonia water to the three-way pipe 11, meanwhile, the air compressor 13 compresses the air and then conveys the compressed air to the three-way pipe 11, the atomized ammonia water and the compressed air are mixed in the three-way pipe, the mixture of the atomized ammonia water and the compressed air is conveyed to the distributor 17 through the three-way pipe 11, the atomized ammonia water and the compressed air are uniformly distributed from the output end of the distributor and then conveyed to the corresponding spray gun 21, and the atomized ammonia water and the compressed air are sprayed into the hearth through the spray gun 21.
Compressed air mixes with atomizing aqueous ammonia outside furnace, need not to increase the pipeline of carrying compressed air, practices thrift the cost on the one hand, and on the other hand can make atomizing aqueous ammonia and compressed air mix more fully to improve the area of contact of flue gas denitration reaction, and then improve flue gas denitration's efficiency.
An electric control valve III 22 is arranged between the air compressor 13 and the three-way pipe 11 and used for controlling the delivery of compressed air, and meanwhile, an electric control valve I18 is arranged on a pipeline between the distributor 17 and the plurality of spray guns 21 and used for controlling the start and stop of the spray guns, so that the spraying of atomized ammonia water and compressed air in different temperature areas in the hearth is controlled.
Example 3
Please refer to fig. 3, which is a flowchart illustrating an SNCR denitration process according to the present embodiment. The embodiment provides a combined denitration method for an industrial gas boiler, which is applied to any one of the combined denitration devices for the industrial gas boiler mentioned in the embodiments 1-2, and comprises an SNCR denitration method, wherein the SNCR denitration method comprises the following steps:
the first step is as follows: the hearth is divided into a plurality of regions with uniform sizes, the load of the industrial boiler is adjusted along with the change of production, the temperatures of different regions in the hearth are changed, the temperatures are monitored in different regions, and ammonia water is sprayed on different regions to enable flue gas to fully react, so that the denitration efficiency is improved;
the second step is that: acquiring the average temperature of different areas in a hearth, wherein the temperature in the hearth is generally higher than 850 ℃, and the acquisition is carried out by using an armored high-temperature sensor;
the third step: finding out an area with the average temperature lower than 850 ℃, an area higher than 1100 ℃ and an area at 850-;
the fourth step: spraying ammonia water and compressed air to the area with the temperature of 850-1100 ℃ by starting the first electric control valve and the second electric control valve of the corresponding area; the non-spraying to other areas is realized by closing the first electric control valve and the second electric control valve of the corresponding areas; and
the fifth step: when the number of the areas with the temperature of 850-1100 ℃ is increased, the number of the spray guns in the spraying state is increased, and the spraying rate of each spray gun in the spraying state is reduced, so that the total spraying rate is kept unchanged; when the number of the areas with the temperature between 850 ℃ and 1100 ℃ is reduced, the number of the spray guns in the spraying state is reduced, and the spraying speed of each spray gun in the spraying state is increased, so that the total spraying speed is kept unchanged. The total spraying rate of the ammonia water and the compressed air is kept unchanged, and sufficient raw materials can be provided for SCR denitration of the flue gas, so that even if the denitration effect of the flue gas is reduced due to the temperature range exceeding 850-1100 ℃, denitration can be continued in the SCR denitration process.
Example 4
Compared with the embodiment 3, after finding out the area with the average temperature lower than 850 ℃, the area with the average temperature higher than 1100 ℃ and the area with the average temperature of 850 ℃ and 1100 ℃ and calculating the corresponding number of the areas, the ammonia water in the corresponding area is diluted by water according to the average temperature. The method for diluting the ammonia water comprises the following steps: when the average temperature of all areas in the hearth is lower than 850 ℃, the mixing ratio of the ammonia water to the water is 1: 0; when the average temperature of all areas in the hearth is higher than 1100 ℃, the mixing ratio of the ammonia water to the water is 1: 3; otherwise, the mixing ratio of the ammonia water and the water is 1: 1. The water content of the ammonia water after dilution is improved, and more water is sprayed into the hearth on the premise that the ammonia content is unchanged, so that the temperature in the hearth is reduced, the water content of the ammonia water which is not diluted is extremely low, the influence on the temperature in the hearth is smaller, the temperature in the hearth is relatively increased, the temperature is returned to between 850 and 1100 ℃, and the flue gas denitration efficiency is improved;
calculating the spraying speed of the spray guns in each area according to the average temperature and the number of the areas; the calculation method of the spraying rate comprises the following steps:
when the average temperature of all the areas in the hearth is lower than 850 ℃, spraying all the areas, wherein the corresponding spraying rates are as follows: p is S/N;
when the average temperature of all the zones in the furnace is higher than 1100 ℃, spraying all the zones, and the corresponding spraying rates are: p is 4S/N;
otherwise, spraying is only performed on the area with the temperature of 850-: p is 2S/n.
Wherein P is the spraying rate in each zone, S is the target spraying rate, N is the number of all zones, and N is the number of zones with the temperature between 850-; the aqueous ammonia is by water dilution back, and its ammonia content also has the difference in the same volume of spraying for the total speed that the spray gun sprayed keeps unchangeable through adjusting the speed that the aqueous ammonia sprayed, avoids arousing denitration effect to reduce because of ammonia content is too high or low excessively.
And spraying a mixture of ammonia water and compressed air into the hearth according to the spraying speed.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.
Claims (10)
1. An industrial gas boiler combined denitration device comprises an SNCR denitration mechanism; the SNCR denitration mechanism includes:
a storage tank (5) for storing ammonia water;
a pressurizing pump (7) one end of which is communicated with the storage tank (5);
the distributor (17) comprises an input end and a plurality of output ends formed by distributing the input end, and the input end is communicated with an outlet at the other end of the pressurizing pump (7); and
the spray guns (21) are respectively communicated with the output ends and are used for spraying ammonia water to different areas in a hearth of the boiler;
characterized in that, SNCR denitration mechanism still includes:
an air compressor (13) comprising a plurality of air outlets which are respectively communicated with a plurality of spray guns (21); the ammonia water distributed by the distributor (17) is mixed with compressed air output by the air compressor (13) and then sprayed by a corresponding spray gun (21);
the first electric control valves (18) are respectively arranged on pipelines between the output ends and the corresponding spray guns (21);
the second electric control valves (20) are respectively arranged on pipelines between the gas outlets and the corresponding spray guns (21);
a plurality of flow meters (16) respectively mounted on the lines between the plurality of outputs and the respective lances (21);
a plurality of temperature sensors (3) for detecting the temperatures of different areas in the furnace respectively; and
the controller (1) judges whether each temperature is between 850 and 1100 ℃, and counts the number of the areas with the temperature between 850 and 1100 ℃; spraying the area with the temperature between 850 ℃ and 1100 ℃ by starting the first electric control valve (18) and the second electric control valve (20) in the corresponding areas; the non-spraying to other areas is realized by closing the first electric control valve (18) and the second electric control valve (20) in the corresponding areas; when the number of the areas with the temperature between 850 ℃ and 1100 ℃ is increased, the number of the spray guns (21) in the spraying state is increased, and the spraying speed of each spray gun (21) in the spraying state is reduced, so that the total spraying speed is kept unchanged; when the number of the areas with the temperature between 850 ℃ and 1100 ℃ is reduced, the number of the spray guns (21) in the spraying state is reduced, and the spraying speed of each spray gun (21) in the spraying state is increased, so that the total spraying speed is kept unchanged.
2. The combined denitration device of an industrial gas-fired boiler according to claim 1, further comprising:
the economizer (23) is arranged on the outer side of the boiler and communicated with a hearth of the boiler;
3. the combined denitration device of an industrial gas-fired boiler as set forth in claim 2, wherein said combined denitration device further comprises:
dust removal mechanism, dust removal mechanism includes:
the filter (25) is communicated with the hearth through the economizer (23), and a plurality of layers of filter screens (27) are arranged in the filter (25); and
and an electrostatic precipitator (29) that electrostatically removes dust from the output of the filter (25).
4. The combined denitration device of the industrial gas-fired boiler as set forth in claim 3, wherein the combined denitration device further comprises an SCR denitration mechanism, the SCR denitration mechanism comprising:
a first gas pipe (31) having one end communicating with the other end of the electrostatic precipitator (29);
a plurality of second air tubes (33) connected to the other end of the first air tube (31) in sequence;
a plurality of electric control valves (35) respectively arranged on the second air pipes (33);
a plurality of SCR reactors (37) respectively communicated with the plurality of second air pipes (33); and
a plurality of catalysts (39) respectively disposed in the plurality of SCR reactors (37).
5. The combined denitration apparatus of an industrial gas boiler as set forth in claim 4, further comprising an exhaust means, said exhaust means comprising:
a back pass (41) having one end in communication with the plurality of SCR reactors (37);
and the chimney (43) is communicated with the other end of the tail flue (41).
6. An industrial gas boiler combined denitration device comprises an SNCR denitration mechanism; the SNCR denitration mechanism includes:
a storage tank (5) for storing ammonia water;
a pressurizing pump (7) one end of which is communicated with the storage tank (5);
the distributor (17) comprises an input end and a plurality of output ends formed by distributing the input end, and the input end is communicated with the outlet at the other end of the pressurizing pump (7); and
the spray guns (21) are respectively communicated with the output ends and are used for spraying ammonia water to different areas in a hearth of the boiler;
characterized in that, SNCR denitration mechanism still includes:
an atomizer (9) one end of which is communicated with the other end of the pressure pump (7);
the three-way pipe (11) comprises two inlets and an outlet, wherein one inlet is connected with the other end of the atomizer (9); one of the outlets is communicated with the input end; and
an air compressor (13) communicating with the other inlet of the tee (11);
the first electric control valves (18) are respectively arranged on pipelines between the output ends and the corresponding spray guns (21);
the third electric control valve (22) is arranged on a pipeline between the air compressor (13) and the corresponding inlet;
a plurality of flow meters (16) respectively mounted on the lines between the plurality of outputs and the respective lances (21);
a plurality of temperature sensors (3) for detecting the temperatures of different areas in the furnace respectively; and
the controller (1) judges whether each temperature is between 850-1100 ℃ and counts the number of the areas with the temperature between 850-1100 ℃; diluting ammonia water in the corresponding area by adopting water according to the average temperature; calculating the spraying speed of the spray guns in each area according to the average temperature and the number of the areas; and spraying a mixture of ammonia water and compressed air into the hearth according to the spraying speed.
7. A combined denitration method for an industrial gas boiler, which applies the combined denitration device for the industrial gas boiler as claimed in any one of claims 1 to 6, and comprises an SNCR denitration method, wherein the SNCR denitration method comprises the following steps:
the first step is as follows: dividing a hearth into a plurality of regions with uniform sizes;
the second step is that: collecting the average temperature of different areas in a hearth;
the third step: finding out the area with the average temperature lower than 850 ℃, the area higher than 1100 ℃ and the area at 850-1100 ℃, and counting the corresponding area number;
the fourth step: spraying ammonia water and compressed air to the region with the temperature of 850-1100 ℃ by starting the first electric control valve (18) and the second electric control valve (20) of the corresponding region; the non-spraying to other areas is realized by closing the first electric control valve (18) and the second electric control valve (20) of the corresponding area; and
the fifth step: when the number of the areas with the temperature between 850 ℃ and 1100 ℃ is increased, the number of the spray guns (21) in the spraying state is increased, and the spraying speed of each spray gun (21) in the spraying state is reduced, so that the total spraying speed is kept unchanged; when the number of the areas with the temperature between 850 ℃ and 1100 ℃ is reduced, the number of the spray guns (21) in the spraying state is reduced, and the spraying speed of each spray gun (21) in the spraying state is increased, so that the total spraying speed is kept unchanged.
8. A combined denitration method for an industrial gas boiler, which applies the combined denitration device for the industrial gas boiler as claimed in any one of claims 1 to 6, and comprises an SNCR denitration method, wherein the SNCR denitration method comprises the following steps:
the first step is as follows: dividing a hearth into a plurality of regions with uniform sizes;
the second step: collecting the average temperature of different areas in a hearth;
the third step: finding out the areas with the average temperature lower than 850 ℃, the areas higher than 1100 ℃ and the areas at 850-1100 ℃, and calculating the corresponding number of the areas;
the fourth step: diluting ammonia water in the corresponding area by adopting water according to the average temperature; the method for diluting the ammonia water comprises the following steps:
when the average temperature of all areas in the hearth is lower than 850 ℃, the mixing ratio of the ammonia water to the water is 1: 0;
when the average temperature of all areas in the hearth is higher than 1100 ℃, the mixing ratio of the ammonia water to the water is 1: 3; and
otherwise, the mixing ratio of the ammonia water to the water is 1: 1;
the fifth step: calculating the spraying speed of the spray guns in each area according to the average temperature and the number of the areas; the calculation method of the spraying rate comprises the following steps:
when the average temperature of all the areas in the hearth is lower than 850 ℃, spraying all the areas, wherein the corresponding spraying rates are as follows: p is S/N;
when the average temperature of all the zones in the furnace is higher than 1100 ℃, spraying all the zones, and the corresponding spraying rates are: p is 4S/N;
otherwise, spraying is only performed on the area with the temperature of 850-: p is 2S/n; and
wherein P is the spraying rate in each zone, S is the target spraying rate, N is the number of all zones, and N is the number of zones with the temperature between 850-; and
and sixthly, spraying a mixture of ammonia water and compressed air into the hearth according to the spraying rate.
9. The combined denitration method for the industrial gas boiler as claimed in claim 7 or 8, further comprising the steps of:
cooling the flue gas, which comprises absorbing the heat of the flue gas by using an economizer and reducing the temperature of the flue gas to between 200 ℃ and 400 ℃;
dedusting the flue gas, which comprises the following steps: performing primary dust removal on the flue gas by using a filter; carrying out secondary dust removal on the flue gas by using an electrostatic dust remover;
10. the combined denitration method for the industrial gas-fired boiler as set forth in claim 9, further comprising the steps of:
SCR denitration, which comprises the following steps: introducing the dedusted flue gas into a plurality of SCR reactors respectively; the flue gas is subjected to reduction reaction with residual ammonia gas and air under the action of a catalyst; and
the method comprises the following steps of: and introducing the denitrated flue gas into a chimney through a tail flue, and discharging the flue gas into the air through a discharge port of the chimney.
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104084017A (en) * | 2014-06-10 | 2014-10-08 | 湖南正明环境工程有限公司 | Denitrification system employing multidirectional-spraying SNCR and single-layer SCR |
| CN206935094U (en) * | 2017-07-10 | 2018-01-30 | 云南澄江天辰磷肥有限公司 | A kind of SNCR equipment for denitrifying flue gas |
| WO2021121575A1 (en) * | 2019-12-18 | 2021-06-24 | Sumitomo SHI FW Energia Oy | Arrangement and method for operating a steam boiler system |
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- 2022-03-07 CN CN202210217459.1A patent/CN114642957A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104084017A (en) * | 2014-06-10 | 2014-10-08 | 湖南正明环境工程有限公司 | Denitrification system employing multidirectional-spraying SNCR and single-layer SCR |
| CN206935094U (en) * | 2017-07-10 | 2018-01-30 | 云南澄江天辰磷肥有限公司 | A kind of SNCR equipment for denitrifying flue gas |
| WO2021121575A1 (en) * | 2019-12-18 | 2021-06-24 | Sumitomo SHI FW Energia Oy | Arrangement and method for operating a steam boiler system |
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Application publication date: 20220621 |