CN113813779A - Sulfur trioxide removal equipment and method for flue gas purification facility comprising SCR denitration system - Google Patents
Sulfur trioxide removal equipment and method for flue gas purification facility comprising SCR denitration system Download PDFInfo
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- CN113813779A CN113813779A CN202111035850.1A CN202111035850A CN113813779A CN 113813779 A CN113813779 A CN 113813779A CN 202111035850 A CN202111035850 A CN 202111035850A CN 113813779 A CN113813779 A CN 113813779A
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- AKEJUJNQAAGONA-UHFFFAOYSA-N sulfur trioxide Chemical compound O=S(=O)=O AKEJUJNQAAGONA-UHFFFAOYSA-N 0.000 title claims abstract description 257
- 239000003546 flue gas Substances 0.000 title claims abstract description 107
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 title claims abstract description 102
- 238000000034 method Methods 0.000 title claims abstract description 40
- 238000000746 purification Methods 0.000 title claims abstract description 21
- 239000002250 absorbent Substances 0.000 claims abstract description 186
- 230000002745 absorbent Effects 0.000 claims abstract description 185
- 239000000243 solution Substances 0.000 claims abstract description 102
- 239000007789 gas Substances 0.000 claims abstract description 75
- 238000002347 injection Methods 0.000 claims abstract description 42
- 239000007924 injection Substances 0.000 claims abstract description 42
- 238000011144 upstream manufacturing Methods 0.000 claims abstract description 23
- 238000005507 spraying Methods 0.000 claims abstract description 18
- 238000010531 catalytic reduction reaction Methods 0.000 claims abstract description 13
- 239000007921 spray Substances 0.000 claims description 62
- 238000004090 dissolution Methods 0.000 claims description 29
- 239000000872 buffer Substances 0.000 claims description 27
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 27
- 239000002594 sorbent Substances 0.000 claims description 23
- 230000008569 process Effects 0.000 claims description 18
- 238000001816 cooling Methods 0.000 claims description 17
- 238000004891 communication Methods 0.000 claims description 15
- 239000012530 fluid Substances 0.000 claims description 15
- 239000000112 cooling gas Substances 0.000 claims description 12
- 238000004140 cleaning Methods 0.000 claims description 9
- 238000010438 heat treatment Methods 0.000 claims description 9
- 230000003472 neutralizing effect Effects 0.000 claims description 7
- 238000000889 atomisation Methods 0.000 abstract description 23
- 230000000694 effects Effects 0.000 abstract description 13
- 238000006477 desulfuration reaction Methods 0.000 abstract description 4
- 230000023556 desulfurization Effects 0.000 abstract description 4
- 239000003570 air Substances 0.000 description 29
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 17
- 239000002245 particle Substances 0.000 description 11
- 239000007788 liquid Substances 0.000 description 9
- 239000002002 slurry Substances 0.000 description 9
- 239000003054 catalyst Substances 0.000 description 8
- 238000006243 chemical reaction Methods 0.000 description 8
- 229910000029 sodium carbonate Inorganic materials 0.000 description 7
- 239000003795 chemical substances by application Substances 0.000 description 6
- 239000000428 dust Substances 0.000 description 6
- 239000000779 smoke Substances 0.000 description 6
- 239000000843 powder Substances 0.000 description 5
- 239000007787 solid Substances 0.000 description 5
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 4
- 238000000227 grinding Methods 0.000 description 4
- 238000005259 measurement Methods 0.000 description 4
- 239000003595 mist Substances 0.000 description 4
- 150000003839 salts Chemical class 0.000 description 4
- 241001625808 Trona Species 0.000 description 3
- 238000010521 absorption reaction Methods 0.000 description 3
- 230000009471 action Effects 0.000 description 3
- 239000012670 alkaline solution Substances 0.000 description 3
- 238000005260 corrosion Methods 0.000 description 3
- 230000007797 corrosion Effects 0.000 description 3
- 230000004069 differentiation Effects 0.000 description 3
- 238000009689 gas atomisation Methods 0.000 description 3
- 230000004048 modification Effects 0.000 description 3
- 238000012986 modification Methods 0.000 description 3
- MWUXSHHQAYIFBG-UHFFFAOYSA-N nitrogen oxide Inorganic materials O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 description 3
- 239000002994 raw material Substances 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- UIIMBOGNXHQVGW-UHFFFAOYSA-M Sodium bicarbonate Chemical compound [Na+].OC([O-])=O UIIMBOGNXHQVGW-UHFFFAOYSA-M 0.000 description 2
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 2
- RAHZWNYVWXNFOC-UHFFFAOYSA-N Sulphur dioxide Chemical compound O=S=O RAHZWNYVWXNFOC-UHFFFAOYSA-N 0.000 description 2
- 230000002411 adverse Effects 0.000 description 2
- 239000012080 ambient air Substances 0.000 description 2
- 229910021529 ammonia Inorganic materials 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 238000001704 evaporation Methods 0.000 description 2
- 230000008020 evaporation Effects 0.000 description 2
- 238000011049 filling Methods 0.000 description 2
- 230000006872 improvement Effects 0.000 description 2
- 229910000069 nitrogen hydride Inorganic materials 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 238000006722 reduction reaction Methods 0.000 description 2
- 239000011734 sodium Substances 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 239000011593 sulfur Substances 0.000 description 2
- 229910052717 sulfur Inorganic materials 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
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 1
- PMZURENOXWZQFD-UHFFFAOYSA-L Sodium Sulfate Chemical compound [Na+].[Na+].[O-]S([O-])(=O)=O PMZURENOXWZQFD-UHFFFAOYSA-L 0.000 description 1
- UIIMBOGNXHQVGW-DEQYMQKBSA-M Sodium bicarbonate-14C Chemical compound [Na+].O[14C]([O-])=O UIIMBOGNXHQVGW-DEQYMQKBSA-M 0.000 description 1
- 239000006096 absorbing agent Substances 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 description 1
- 239000000920 calcium hydroxide Substances 0.000 description 1
- 229910001861 calcium hydroxide Inorganic materials 0.000 description 1
- 238000006555 catalytic reaction Methods 0.000 description 1
- 239000013043 chemical agent Substances 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000002425 crystallisation Methods 0.000 description 1
- 230000008025 crystallization Effects 0.000 description 1
- 230000009849 deactivation Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 239000003344 environmental pollutant Substances 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- 150000004679 hydroxides Chemical class 0.000 description 1
- 230000002779 inactivation Effects 0.000 description 1
- 206010022000 influenza Diseases 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- NEMFQSKAPLGFIP-UHFFFAOYSA-N magnesiosodium Chemical compound [Na].[Mg] NEMFQSKAPLGFIP-UHFFFAOYSA-N 0.000 description 1
- 239000011777 magnesium Substances 0.000 description 1
- 229910052749 magnesium Inorganic materials 0.000 description 1
- VTHJTEIRLNZDEV-UHFFFAOYSA-L magnesium dihydroxide Chemical compound [OH-].[OH-].[Mg+2] VTHJTEIRLNZDEV-UHFFFAOYSA-L 0.000 description 1
- 239000000347 magnesium hydroxide Substances 0.000 description 1
- 229910001862 magnesium hydroxide Inorganic materials 0.000 description 1
- 239000000395 magnesium oxide Substances 0.000 description 1
- CPLXHLVBOLITMK-UHFFFAOYSA-N magnesium oxide Inorganic materials [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 description 1
- AXZKOIWUVFPNLO-UHFFFAOYSA-N magnesium;oxygen(2-) Chemical compound [O-2].[Mg+2] AXZKOIWUVFPNLO-UHFFFAOYSA-N 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 238000003801 milling Methods 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 238000005192 partition Methods 0.000 description 1
- 238000005498 polishing Methods 0.000 description 1
- 231100000719 pollutant Toxicity 0.000 description 1
- 238000005086 pumping Methods 0.000 description 1
- 238000004064 recycling Methods 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 238000004088 simulation Methods 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- 229910000030 sodium bicarbonate Inorganic materials 0.000 description 1
- 235000017557 sodium bicarbonate Nutrition 0.000 description 1
- 229910052938 sodium sulfate Inorganic materials 0.000 description 1
- 235000011152 sodium sulphate Nutrition 0.000 description 1
- 238000000638 solvent extraction Methods 0.000 description 1
- 238000001694 spray drying Methods 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 239000000725 suspension Substances 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
- B01D53/86—Catalytic processes
- B01D53/8621—Removing nitrogen compounds
- B01D53/8625—Nitrogen oxides
- B01D53/8628—Processes characterised by a specific catalyst
-
- 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
- B01D53/14—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by absorption
- B01D53/1456—Removing acid components
- B01D53/1481—Removing sulfur dioxide or sulfur trioxide
-
- 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
- B01D53/14—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by absorption
- B01D53/18—Absorbing units; Liquid distributors therefor
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2258/00—Sources of waste gases
- B01D2258/02—Other waste gases
- B01D2258/0283—Flue gases
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Analytical Chemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Environmental & Geological Engineering (AREA)
- Health & Medical Sciences (AREA)
- Biomedical Technology (AREA)
- Treating Waste Gases (AREA)
Abstract
The invention provides sulfur trioxide removal equipment for a flue gas purification facility and a corresponding method. The flue gas purification facility comprises a Selective Catalytic Reduction (SCR) denitration system, and the equipment comprises an absorbent dissolving tank, a compressed gas source and an atomization and injection unit, wherein the atomization and injection unit utilizes the compressed gas to atomize and inject an absorbent solution into a flue positioned at the upstream and/or the downstream of the SCR denitration system. The device and the method provided by the invention achieve excellent desulfurization effect on the flue gas in the SCR denitration system by atomizing and spraying the absorbent solution and using a lower absorbent dosage.
Description
Technical Field
The invention relates to the field of flue gas desulfurization, in particular to sulfur trioxide removal equipment and a method for a flue gas purification facility comprising a Selective Catalytic Reduction (SCR) denitration system.
Background
Selective Catalytic Reduction (SCR) systems have been widely usedNitrogen Oxide (NO) of coal-fired unitsx) In the flue gas purification treatment. The SCR denitration system converts nitrogen oxides in the flue gas into nitrogen through a catalyst, so that high-efficiency flue gas denitration is realized.
However, along with the popularization of the SCR denitration system, sulfur trioxide (SO) associated with the flue gas is also generated3) A new problem is concerned. Preliminary investigations have been made regarding this problem. For example, chinese patent application CN103055684A proposes that the sulfur trioxide content in the flue gas discharged from the SCR denitration system increases, and causes corrosion and blockage of the air preheater (also referred to as air preheater). To solve this problem, this patent application achieves SO between the SCR reactor tail and the air preheater inlet by injecting a trona slurry through an array of nozzles, e.g. 150mm in diameter, after the flue gas leaves the SCR reactor and before it enters the air preheater3The removal efficiency reaches 87 percent under the condition that the molar weight of the absorbent is 9 times of the dosage of the absorbent. The Chinese patent application CN104474897A proposes that in an SCR denitration system, SO is used as a catalyst3Possibly with water vapor, NH3Reaction to form H2SO4And NH4HSO4And the deposit is deposited at the SCR catalyst reactor and the air preheater to cause catalyst failure and blockage of the air preheater, so that the problems of low-load forced retreat, catalyst inactivation, blockage of the air preheater and the like occur after the SCR denitration device is installed on a coal-fired unit, and the denitration efficiency of a coal-fired power plant and the normal operation of the unit are influenced. The solution proposed in this patent application is to inject calcium hydroxide, magnesium oxide, magnesium hydroxide, sodium bicarbonate or sodium carbonate particles as a removal agent into the flue gas.
However, in the above method, the removal effect is not ideal in spite of the high amount of the chemical agent. There remains a need for development and improvement in the treatment of sulfur trioxide in SCR denitration systems.
Disclosure of Invention
The invention provides sulfur trioxide removal equipment for a flue gas purification facility, wherein the flue gas purification facility comprises a Selective Catalytic Reduction (SCR) denitration system arranged in a flue, and the sulfur trioxide removal equipment is characterized by comprising:
an absorbent dissolution tank configured to hold SO3An absorbent solution;
a compressed gas source configured to provide compressed gas; and
an atomizing spray unit in fluid communication with the sorbent dissolution tank and the compressed gas source and configured to utilize the compressed gas to disperse the SO3An absorbent solution is atomized and sprayed into the flue.
Optionally, the absorbent dissolution tank comprises an absorbent solution heating device.
Optionally, the atomizing injection unit is configured to at least inject the SO3An absorbent solution is injected into the flue upstream of the SCR denitration system.
Optionally, the atomizing spray unit comprises:
a buffer container;
an atomizing nozzle disposed in the buffer vessel, the atomizing nozzle in fluid communication with the sorbent dissolution tank and the compressed gas source, and configured to utilize the compressed gas to subject the SO to3Atomizing and spraying an absorbent solution into the buffer container; and
a grill unit disposed in the flue, the grill unit in fluid communication with the outlet of the buffer vessel.
Optionally, the atomizing spray unit comprises:
an atomizing nozzle disposed in the flue, the atomizing nozzle in fluid communication with the sorbent dissolution tank and the compressed gas source, and configured to utilize the compressed gas to subject the SO to3The sorbent solution is atomized and sprayed into the flue.
Optionally, the sulfur trioxide removal apparatus further comprises an atomizing nozzle cooling device.
Optionally, the atomising nozzle cooling means comprises a cooling air passage.
Optionally, the sulfur trioxide removal device comprises a control system configured to control the atomizing injection unit to differentiate the sorbent solution injection zones in the flue.
In another aspect, the present invention provides a sulfur trioxide removal method for a flue gas cleaning facility comprising a selective catalytic reduction, SCR, denitration system disposed in a flue, characterized in that the method comprises:
using SO3Preparing SO from absorbent and water3The absorbent solution is a solution of an absorbent,
using compressed gas to mix the SO3An absorbent solution is atomized and sprayed into the flue.
Optionally, the SO injected into the flue per unit time3SO in absorbent solution3The molar quantity of the absorbent is SO required for neutralizing sulfur trioxide in the flue gas flowing into the flue31 to 2 times the molar amount of absorbent.
Optionally, the SO3The sorbent solution is heated and injected into the flue upstream of the SCR denitration system.
Optionally, the injection coverage of the injection in the flue is 150% to 200%.
Optionally, according to SO of the flue gas3Content and flow field distribution of the flue gas in the flue, and the spraying subareas of the absorbent solution in the flue are differentiated.
Drawings
Figure 1 shows a schematic view of one embodiment of the apparatus of the present invention.
Figure 2 shows a schematic view of yet another embodiment of the apparatus of the present invention.
Figure 3 shows a schematic view of yet another embodiment of the apparatus of the present invention.
Figure 4 shows a schematic view of one embodiment of the arrangement of spray guns in the flue.
Detailed Description
The inventor finds that the consumption of the absorbent is increased sharply in order to improve the removal efficiency of the existing sulfur trioxide treatment method in the SCR denitration system. For example, in CN104474897AIn the trona slurry injection method, trona and SO3When the molar ratio of (A) to (B) is 9: 1, the removal efficiency reaches 87%. The particulate injection method of CN104474897A states that the injection amount of the removing agent is 2 to 6 times the mole number of sulfur trioxide to be removed, but its effect is not disclosed. Moreover, this patent application does not disclose how to actually achieve the injection of the powder remover. In fact, the present inventors have found that the sulfur trioxide removal effect is not significant when the gas-solid reaction is carried out with the amount of the removing agent of the present patent application. Furthermore, none of the related methods involves fine control of the nozzles.
At least in order to achieve an excellent sulfur trioxide removal effect with a lower amount of an absorbent, the present invention provides a sulfur trioxide removal apparatus for a flue gas purification facility including a selective catalytic reduction SCR denitration system provided in a flue, characterized in that the sulfur trioxide removal apparatus includes:
an absorbent dissolution tank configured to hold an absorbent solution;
a compressed gas source configured to provide compressed gas; and
an atomizing spray unit in fluid communication with the sorbent dissolution tank and the compressed gas source and configured to atomize and spray the sorbent solution into the flue with the compressed gas.
The sulfur trioxide removal apparatus and method of the present invention are used in flue gas cleaning facilities containing Selective Catalytic Reduction (SCR) denitration systems, and are specifically used to address SO in flue gas associated with SCR denitration systems3Causing problems. Without being bound to any theory, the inventors of the present invention found that the inevitable temperature of the flue gas treated by a flue gas purification facility comprising an SCR denitration system is high, since low temperature flue gas is not sufficient for SCR; meanwhile, only when a large amount of flue gas needs to be treated, the SCR denitration system is worthy of being arranged, so that the flue gas flow is large. The inventors have thus found that the sulfur trioxide removal means in the related art, which can be applied to normal temperature gas or low flow rate gas, is not applicable to the SCR denitration systemThe flue gas of (1). For example, sulfur trioxide in a small amount of gas can be removed by passing the gas through an alkaline solution tank, but if a large flow of high-temperature flue gas is passed through the alkaline solution tank, water in the alkaline solution can be rapidly evaporated, the removal process is poor in continuity and has high requirements for equipment. In addition, another characteristic of the flue gas related to the SCR denitration system is that the pollutants are not mainly sulfur trioxide, and therefore, if a purification device for sulfur trioxide, such as a spray tower, is independently installed in the flue gas purification facility, the economy is poor, and the efficiency is low.
The flue gas purification facility applicable to the sulfur trioxide removal equipment comprises an SCR denitration system arranged in a flue, wherein flue gas enters the SCR denitration system through an upstream flue, and enters a downstream flue after denitration. As described below, the sulfur trioxide removal device of the present invention can remove sulfur trioxide from flue gas in both downstream and upstream flues.
The sulfur trioxide removal apparatus of the present invention comprises three main components: the device comprises an absorbent dissolving box, a compressed gas source and an atomizing and spraying unit.
The absorbent dissolving box of the invention is used for containing SO3An absorbent solution which is subsequently fed into the flue to absorb SO3。SO3The absorbent is optionally mixed with SO3The substances which react and thus remove them from the flue gas, hereinafter sometimes also referred to simply as absorbents. SO (SO)3The absorbent solution is a solution formed by dissolving an absorbent in water. Typical SO3Absorbents are solid alkaline substances which can react with sulfur trioxide to neutralize it to form salts, and they can therefore also be referred to as neutralizing agents. The usual SO may be used3The neutralizer is used as an absorbent. Common SO3Solid neutralizing agents include, for example, sodium-and magnesium-based neutralizing agents, and more specifically include oxides, salts, hydroxides, and the like of sodium and magnesium. The most preferred absorbents are selected from sodium carbonate and sodium bicarbonate, as these are associated with SO3Easy reaction and good fixation effect of the product sodium sulfate on sulfur. Preferably, the water used in the absorbent solution is a demineralized water to avoid interference of extraneous ions with the reaction of the absorbent with sulfur trioxide.
The absorbent dissolution tank may also have auxiliary SO3Means for dissolving the absorbent, such as stirring means, are used to accelerate the dissolution of the absorbent.
The sorbent dissolution tank provides SO to an atomizing spray unit, which will be described in detail below, through a fluidly connected conduit3An absorbent solution. For example, the absorbent solution may be supplied by a pumping device, or may be caused to flow from an overhead absorbent dissolution tank to the atomizing spray unit, for example, by gravity.
In one embodiment, in order to supply the absorbent solution to the absorbent dissolution tank, an absorbent reserve tank and a demineralized water supply system may be provided upstream of the absorbent dissolution tank. The absorbent is provided from the absorbent storage container and the demineralized water is provided from the demineralized water providing system according to the proportion, and the absorbent solution is formed by uniformly mixing the absorbent and the demineralized water in the absorbent dissolving tank.
When the raw material particles of the absorbent are large, it is preferable that the raw material particles are ground to a particle size of 20mm or less using an absorbent grinding apparatus before being supplied to the dissolution of the absorbent. Grinding can make absorbent particles smaller and uniform and improve the dissolving speed of the absorbent. Since the purpose of milling is to promote dissolution, it may not be necessary to mill too finely. For example, the polishing may be carried out until the particle size is 0.5mm or more, 1mm or more, or 5mm or more.
The source of compressed gas in the sulfur trioxide removal device is used to provide compressed gas, also referred to as high pressure gas, to the atomizing injection unit. The high pressure of the compressed gas can simultaneously serve to atomize and spray the absorbent solution. Typically and preferably, the source of compressed gas is a source of compressed air. The air source is readily available and does not adversely affect flue gas treatment. The pressure of the compressed gas may be 2-5 bar. The flow ratio of compressed gas to absorbent solution is typically from 100 to 600. The pressure and flow of the compressed gas can be adjusted by the coverage and atomization effect to be achieved.
The atomization injection unit in the sulfur trioxide removal equipment is used for injecting the absorbent solution into the flue in the form of atomized liquid drops to absorb SO3I.e. with both atomisation and sprayingThe function of (c). Atomization refers to the process of making a liquid into a mist of droplets. Conventional atomization means include compressed gas atomization, ultrasonic atomization, and the like. In the invention, compressed gas is selected for atomization, because the compressed gas can meet the requirement of fully injecting atomized liquid drops into the flue. Moreover, the environment in the flue is relatively complex, so compared with atomization methods such as ultrasonic waves, the atomization component of the compressed gas atomization method is more durable. The atomizing spray unit may employ various specific air compression spray elements and means, as long as it is sufficient to sufficiently atomize the absorbent solution and the absorbent sprayed into the flue is still in the form of droplets dissolved in water.
The sulfur trioxide removal apparatus of the present invention achieves sulfur trioxide removal by forming a spray of an absorbent solution. Compared with the dry removal method of directly spraying absorbent powder, the spray of the invention can realize the further refinement of the absorbent, thereby improving the removal efficiency. The inventors have found that in dry removal, such as the process described in CN104474897A, the sprayed sorbent powder, even though it has been ground to below 50 microns, acts as SO in the flue3The absorbent, which still has large particles and settles quickly due to its own weight. This results in an insufficient utilization of the absorbent and in an increased amount of absorbent or a poor removal effect. Further refinement of the absorbent powder particles greatly increases time and facility costs, and has limited improvement in effectiveness. In addition, the efficiency of gas-solid reactions in the flue is low. In processes utilizing a sprayed or sparged slurry stream, such as the process described in CN103055684A, the sparged slurry stream is poorly contacted with flue gas, and a significant amount of the absorbent in the slurry stream does not participate in the reaction of sulfur trioxide, with white losses. Even if the dosage of the absorbent is increased to 9: 1 of the molar ratio of the absorbent to sulfur trioxide, the removal efficiency is not ninety percent, and the comprehensive efficiency is low. Furthermore, in both processes, the presence of large amounts of unreacted excess sorbent not only increases costs, but also leads to an unnecessary increase in dust or liquid in the flue gas, placing a burden on the flue gas dust removal or drainage.
The invention provides for the absorbent to be brought into contact with the flue gas using a spraying process with the aid of a compressed gas. The atomized micro-droplets are small in size and are easily suspended in the flue gas, so the utilization efficiency of the absorbent is far higher than the way of spray drying absorbent powder. Under the action of compressed gas, atomized micro liquid drops are fully contacted with flue gas, so that the absorbent in the solution can be fully utilized, and the waste in a slurry spraying method is avoided.
The micro-droplets are contacted with high-temperature flue gas, so that moisture can be volatilized, and the dried absorbent can be directly contacted with the flue gas. Furthermore, it is also possible that the sulfur trioxide is first dissolved in the microdroplets and neutralized to form salts, after which the water is completely evaporated. During the suspension of the atomized absorbent liquid drops in the smoke, the two mechanisms work together to fully utilize the absorbent in the absorbent solution. Under ideal conditions, water is fully volatilized, the utilization rate of the absorbent can be close to 100 percent, thereby greatly saving the using amount of the absorbent and reducing the burden of dust removal and liquid removal.
The median volume diameter of the spray droplets obtained by compressed gas atomization may be below 1000 microns, below 500 microns, below 200 microns, even below 50 microns, more preferably from 10 to 30 microns, still more preferably from 15 to 25 microns. Without being bound to any theory, the smaller the atomized droplets, the more readily the sorbent therein will fully react with the flue gas in the flue. The diameter of the spray droplets can be suitably designed according to the specific sulfur content, flow rate, temperature, etc. in the flue gas.
After sulfur trioxide is removed, the water in the absorbent solution is changed into harmless water vapor in the flue gas and finally discharged. The dry salt solids formed can be removed from the flue gas when passing through a dust removal device such as a bag-type dust remover.
The temperature of the atomized and sprayed absorbent solution is obviously lower than the temperature of the flue gas, so that the temperature of the flue gas is reduced. However, because the atomization mode is used for providing the absorbent solution, the absorbent can be fully utilized compared with a slurry spraying mode, the water consumption is greatly reduced, the total heat capacity is small, and the temperature reduction range of the flue gas is small. Therefore, the method can also be used at the upstream of the SCR denitration system, and the catalytic reaction is not adversely affected due to the great reduction of the flue gas temperature. In contrast, the manner of injecting a large amount of slurry can significantly lower the temperature of the flue gas, and cannot be used upstream of the SCR denitration system.
Preferably, the absorbent dissolution tank further comprises an absorbent solution heating device. Heating means, such as a heater or heat exchanger, are used to bring the solution above ambient temperature, for example at a temperature that causes the solubility of the absorbent to be greater, to increase the solubility of the absorbent in water, while also preventing problems such as crystallization due to supersaturation of the solution as a result of the temperature decrease. However, when the temperature is too high, the amount of water evaporated is too large, the solution is unstable and the structural requirements for the absorbent dissolution tank are high. Preferably, the temperature of the absorbent solution is controlled to be 20 ℃ to 80 ℃, more preferably 30 ℃ to 60 ℃, more preferably 30 ℃ to 50 ℃, more preferably 40 ℃ to 50 ℃. In this temperature range, the solubility of the absorbent is relatively high and the evaporation of water from the solution is not significant. In addition, increasing the temperature of the absorbent solution may further reduce the cooling effect on the flue gas as described above, and is more suitable for use upstream of the SCR denitration system. The absorbent dissolving box is also preferably provided with a heat-insulating shell, so that the heating effect of the solution is improved. The absorbent dissolution tank also preferably has a temperature measuring device to control the heating device.
In the present invention, the location of the injection of the atomized sorbent solution may be in the flue upstream and/or downstream of the SCR denitration system. As mentioned above, if SO is contained in the flue gas introduced into the SCR denitration system3High content of it will react with NH3Reacting to produce a product that affects the SCR catalyst reactor; the flue gas discharged from the SCR denitration system generates new products which affect the quality of the air preheater and the ambient air. Therefore, in the present invention, the flue position to spray the absorbent solution mist may be upstream, downstream, or both of the denitration system. Preferably, the atomizing spray unit is configured to at least spray the SO3An absorbent solution is injected into the flue upstream of the SCR denitration system. Injecting upstream of an SCR denitration system may prevent SO3Resulting in deactivation of the catalyst in the SCR reactor.
More specific injection locations may be the SCR denitration system inlet, the SCR denitration system outlet, the air preheater outlet, and the wet desulfurization absorber inlet. The SCR denitration system inlet is a position upstream of the SCR ammonia injection process. The SCR denitration system outlet may be a location between the SCR reactor outlet and the air preheater inlet. The air preheater is a conventional device in tail gas treatment of an SCR denitration system and is used for recycling heat energy of the tail gas. The flue may also be located at the air preheater exit. The flue can also be arranged before the wet desulphurization absorption tower. The wet desulfurization absorption tower is a conventional device in tail gas treatment of an SCR denitration system and is used for removing sulfur dioxide in the tail gas.
There are various embodiments of the atomizing spray unit. When designing an atomization spraying unit, how to realize the spraying of atomized liquid drops in a high-temperature flue gas environment is a problem to be solved particularly.
In one embodiment of the present invention, an atomizing spray unit includes:
a buffer container;
an atomizing nozzle disposed in the buffer vessel, the atomizing nozzle in fluid communication with the sorbent dissolution tank and the compressed gas source, and configured to utilize the compressed gas to subject the SO to3Atomizing and spraying an absorbent solution into the buffer container; and
a grill unit disposed in the flue, the grill unit in fluid communication with the outlet of the buffer vessel.
In this embodiment, a buffer container, such as a buffer chamber, is provided. The buffer container is used for pre-forming gas containing absorbent fog drops outside the flue, and then the gas containing the absorbent fog drops is further sprayed into the flue. The buffer container has the advantage that the atomization can be carried out in an environment which is not related to the flue environment and forms gas containing fog drops, so that the specific environment of the flue, such as flue temperature, flue gas flow and the like, does not influence the atomization process.
The compressed gas atomizes the absorbent solution at an atomizing nozzle provided in the buffer vessel, so that the buffer vessel is filled with gas carrying a large amount of mist droplets of the absorbent solution. The atomizing nozzle may be disposed at an inlet of the buffer vessel. The solution droplets are further driven by the compressed gas continuously introduced subsequently to leave the buffer container and pass through the fluid communication pipeline to reach one or more grid units arranged in the flue, enter the flue from the grid units, and then carry the absorbent solution droplets into the flue to react with sulfur trioxide in the flue gas.
The grid unit is a grid type structure that guides the gas, and can control the position, angle, and flow thickness of the gas injected into the flue, but does not actively pressurize or accelerate the gas. The specific structure of the grid elements can be arranged according to the specific shape of the flue and the flue gas flow field distribution to obtain the proper sprayed gas and fog drops. More preferably, the grid elements are zone adjustable to achieve fine zone control in the flue.
In another embodiment of the present invention, the atomizing spray unit comprises:
an atomizing nozzle disposed in the flue, the atomizing nozzle in fluid communication with the sorbent dissolution tank and the compressed gas source, and configured to utilize the compressed gas to subject the SO to3The sorbent solution is atomized and sprayed into the flue.
In this embodiment, the spray may be formed directly in the flue by an atomizing nozzle disposed in the flue. The atomising nozzle may be in the form of a spray gun. The spraying may be accomplished by one or more atomizing nozzles. The atomizing nozzle may be a conventional nozzle for spraying with a compressed gas. Preferably, the position, angle, spray pattern, etc. of the atomizing nozzles can be set according to the specific shape of the flue and the flue gas flow field distribution to obtain a suitable spray of gas and mist droplets. More preferably, the atomizing nozzle is zone adjustable to achieve fine zone control in the flue.
The inventor finds that the arrangement of the atomizing nozzle directly in the flue needs to take into account the influence of the flue environment. In particular, in the case of high temperature flue gases, especially when the flue is upstream of an SCR denitration system, for example, the flue gas temperature is high. At this time, the local surrounding of the nozzle opening is subjected to a high temperature environment, which may cause a part of the absorbent solution near the wall of the nozzle opening to be insufficiently atomized and sprayed out of the nozzle, and the moisture therein is completely evaporated, thereby causing problems such as nozzle clogging. In this case, the sulfur trioxide removal apparatus may further comprise an atomizing nozzle cooling device. The cooling device is used for enabling the periphery of the nozzle opening to be in an environment with lower temperature relative to the flue gas, so that the atomization and the injection of the absorbent solution can be smoothly completed.
The cooling device of the atomizing nozzle in the flue and the heating device of the absorbent dissolving box can cooperate, so that the atomized absorbent can enter the flue through the nozzle at a proper temperature, the nozzle is not blocked or failed due to overhigh local temperature at the periphery of the nozzle, and the absorbent is not separated out early or the smoke temperature is reduced obviously due to overlow spraying temperature of the main absorbent.
The cooling means may take a number of suitable forms. For example, a water cooling unit may be provided to achieve cooling. More preferably, the atomizing nozzle cooling means cools the atomizing nozzle using cooling gas. The cooling gas can be directly discharged into the flue, and the structure is simple. Specifically, compressed air may be selected as the cooling gas. The cooling gas may be any gas having a temperature lower than that of the flue gas, preferably a room temperature gas such as ambient air is used directly. The flow rate of the cooling gas can be adjusted by the actual need. To this end, the atomizing nozzle cooling device may include a cooling air passage. The cooling gas passage and the absorbent solution passage in the atomizing nozzle may be independent of each other, for example, by being injected into the flue through a sandwich outside the nozzle. In this case, the cooling gas serves merely to cool and protect the nozzle, without causing excessive interference with the atomization of the absorbent solution. However, for simplicity, the cooling gas passage may be directly provided in the absorbent solution passage, that is, in the nozzle, and may be ejected together with the absorbent solution, thereby participating in atomization of the absorbent solution. In any case, in the invention, when the cooling device is used, the temperature near the nozzle opening is properly regulated, so that the absorbent solution is ensured to be normally sprayed, and meanwhile, the temperature of the flue gas is not greatly reduced.
Whether the spraying in the flue is done by means of a grid unit, atomising nozzles or other possible spraying means, the upstream ducting should be arranged to distribute the droplets carrying the absorbent solution appropriately according to the flue conditionsOr an absorbent solution. Also, the spray member may be provided in multiple layers along the length of the flue to sufficiently cover the flue. Preferably, the coverage of the flue by the atomized spray is 150% to 200%, too low an impact on SO3The removal effect is too high, and the cost is increased. Here, the coverage ratio refers to a ratio of a total area covered by the spray of each spray head to a cross-sectional area of the flue. Furthermore, the compressed gas parameters matched to the injection means should be suitably adjusted to obtain a suitable injection velocity.
The sulfur trioxide removal apparatus of the present invention may further comprise a control system configured to control the atomizing injection unit to differentiate the sorbent solution injection zones in the flue. The partition differentiation means that the atomization and injection parameters are different in different areas of the flue. For example, different injection amounts may be provided. The control system can control atomization injection in a partitioning mode according to measurement or simulation of a flow field in the flue, and differentiation is achieved.
In one embodiment, the sulfur trioxide removal apparatus of the present invention may further comprise a plurality of absorbent dissolution tanks or a plurality of compressed gas sources, such that different concentrations of absorbent and gas pressure may be provided simultaneously, further facilitating the implementation of zone-wise differential atomizing injection.
The invention also provides a sulfur trioxide removal method for a flue gas purification facility, wherein the flue gas purification facility comprises a Selective Catalytic Reduction (SCR) denitration system arranged in a flue, and the method is characterized by comprising the following steps:
using SO3Preparing SO from absorbent and water3The absorbent solution is a solution of an absorbent,
using compressed gas to mix the SO3An absorbent solution is atomized and sprayed into the flue.
The method of the invention may be carried out using the apparatus of the invention. The process of the present invention has the aforementioned advantages over dry or slurry processes.
Preferably, the SO injected into the flue per unit time3SO in absorbent solution3The molar quantity of the absorbent is required for neutralizing sulfur trioxide in the flue gas flowing into the flueSO of (A)3The molar amount of the absorbent is 1 to 2 times, more preferably 1.2 to 1.8 times, more preferably 1.4 to 1.6 times, for example 1.5 times. Since the absorbent can react with SO in the process of the invention3The contact reaction is sufficient, the utilization rate is high, SO that 1 to 2 times of absorbent can basically and sufficiently remove SO3. More preferably, about 1.5 times the absorbent ensures SO3Is removed sufficiently. The proportion of the two can be controlled by the injection flow and can be adjusted according to SO in the flue gas3The concentration variation of the spray nozzle adjusts the spray flow rate. The control of the injection flow can be achieved by adjusting the parameters of the compressed gas and the absorbent solution.
As described above, the spray coverage in the flue is preferably 150% to 200%.
Preferably, SO is added3The sorbent solution is heated and injected into the flue upstream of the SCR denitration system. The beneficial effects are as described hereinbefore.
Preferably, according to SO of the flue gas3The content and the flow field distribution of the flue gas in the flue, and the atomized injection of the absorbent solution in the flue is subjected to subarea differentiation.
Preferably, the mass concentration of the absorbent in the absorbent solution is between 10% and 30%. When the concentration is too low, the water content is too high, and the carrying efficiency of the absorbent is low. If the concentration is too high, crystals are likely to precipitate due to a decrease in temperature, or drying is too fast at high temperatures, both of which are disadvantageous for continuous operation of the ejection part.
Figure 1 shows a schematic view of one embodiment of the apparatus of the present invention. As shown in FIG. 1, an absorbent dissolution tank 1 and a compressed air source 2 as a compressed air source are both in fluid communication with an atomizing spray unit 3 for providing SO, respectively3An absorbent solution and compressed air. The front end of the absorbent dissolution tank may receive absorbent particles 4 and demineralized water from a demineralized water tank 5, thereby forming an absorbent solution. After the absorbent solution reaches the atomization injection unit, the absorbent solution is atomized and injected into the flue 6 under the action of compressed air to contact with the flue gas 7 flowing in the flue, so that the removal of sulfur trioxide is realized.
Figure 2 shows a schematic view of yet another embodiment of the apparatus of the present invention. In fig. 2, the atomizing spray unit specifically includes: a buffer container 32; an atomizing nozzle 31 provided in the buffer container, the atomizing nozzle being configured to atomize and spray the absorbent solution into the buffer container with compressed air; and a plurality of grill units 33 disposed in the flue, the grill units being in fluid communication with the outlet of the buffer vessel. In this way, a gas carrying the atomized absorbent solution is first formed in the buffer vessel, which gas is further sprayed into the flue through the spray grid. Therefore, the atomization process is separated from the injection process, and the flue environment is not influenced.
Figure 3 shows a schematic view of yet another embodiment of the apparatus of the present invention. In fig. 3, the atomizing spray unit specifically includes: a lance 31 as an atomizing nozzle disposed in the flue. The absorbent solution is directly injected from the spray gun into the flue under the action of compressed air. Because the spray gun is in the flue, the high temperature flue gas in the flue may cause the absorbent solution to dry prematurely, which is not conducive to forming a spray. In this embodiment, cooling gas 8 is simultaneously supplied to the lance nozzle periphery. The cooling gas may be a compressed gas having a room temperature. Due to the continuous introduction of the cooling gas, the temperature of the spray gun can be always kept at a temperature which does not cause the too fast evaporation of the absorbent solution, thereby realizing the continuous atomization and injection.
Examples
Example 1
The sulfur trioxide removal equipment shown in fig. 2 is used for removing sulfur trioxide from the flue gas of the flue gas purification facility including the selective catalytic reduction SCR denitration system.
The position of the injection grid is in the position of an SCR outlet straight pipe section of the flue gas purification facility. The flue gas temperature measured upstream of this location was 340 ℃ with SO3The content is 131mg/Nm3. Flue gas is standard state and contains 6% of O2The dry flue gas of (1). Furthermore, the flow field in the flue is uniform here.
Sodium carbonate (Na) is selected2CO3) The absorbent is prepared by grinding the raw materials to particle size of 20mm or less, filling into an absorbent dissolution box, introducing desalted water into the absorbent dissolution box, and heating to 40 deg.C to obtain an absorbent solution with mass concentration of 18%. Dissolving the absorbent in waterLiquid at 1.8m3The flow/h leads to the atomizing nozzle. The compressed air pressure was 3bar at 200m3The flow/h leads to the atomizing nozzle. The atomizing nozzle is arranged at the inlet of the buffer vessel and an atomized solution with a droplet size of 25 μm is formed in the buffer vessel and is further sprayed into the flue through a spray grid with a size of 13m x 4 m. In order to match with a flow field, the distribution of the injection grids in the flue is in regular triangle arrangement, and the injection coverage rate is 150%. Absorbent introduced into flue per unit time and SO neutralized3The desired molar ratio of absorbent is about 1.8: 1.
After the start of the run, the SO in the flue gas downstream of the injection grid is measured3The content is 5.5mg/Nm3. The sulfur trioxide removal rate reaches 95.8 percent.
After 1 hour, the SO in the flue gas upstream of the grid is measured again3The content of the smoke gas is reduced to 102mg/Nm due to the change of the working condition of the equipment generating the smoke gas3. Based on the above measurements, the flow rate of the absorbent solution was adjusted to 1.4m by the control system3H, keeping the absorbent introduced into the flue per unit time and neutralizing SO3The desired molar ratio of absorbent is about 1.8: 1.
Measurement of SO in flue gas downstream of injection grid3The content is 5.3mg/Nm3. The sulfur trioxide removal rate reaches 94.8 percent.
Treated SO3The content is always kept at a low level, no corrosion is caused to the air preheater, and the emission standard is also met.
Therefore, the embodiment achieves an excellent sulfur trioxide removal effect by using a lower absorbent, and ensures the normal operation of the SCR denitration system.
Example 2
The sulfur trioxide removal equipment shown in fig. 3 is used for removing sulfur trioxide from the flue gas of the flue gas purification facility including the selective catalytic reduction SCR denitration system. Wherein, a plurality of spray guns are arranged in the flue.
The spray gun is positioned at the position of the SCR outlet straight pipe section of the flue gas purification facility. At this point, the flue gas temperature was measured to be 330 ℃ with SO3The content is 88mg/Nm3. In addition, the flow field in the flue is uniform.
Selecting sodium carbonate as an absorbent, finely grinding the sodium carbonate to the particle size of less than 20mm, filling the sodium carbonate into an absorbent dissolving box, simultaneously introducing desalted water into the absorbent dissolving box, and heating the sodium carbonate to 40 ℃ to form an absorbent solution with the mass concentration of 20%. The absorbent solution was brought to 1.5m3The flow/h is directed to the lance. The compressed air pressure was 3.2bar at 250m3The flow/h is directed to the lance. At the same time, the cooling air of room temperature was cooled at 250m3The flow/h is directed to the lance. The spray gun directly forms an atomized solution with the droplet size of 15 mu m in the flue, the spray gun is matched with a flow field, the spray gun is distributed in the flue in a regular triangle shape, and the spray coverage rate is 150%. The arrangement of the regular triangular distribution of the spray guns is shown in fig. 4 (a). The figure shows a section of the flue, the arrow in the lower right direction indicating the direction of the flue gas flow. The open circles indicate the position of the gun nozzle and the dotted lines schematically show the spray it sprays. A spray coverage of 150% was achieved by first placing one lance in the center and then two side-by-side lances downstream. Fig. 4(b) shows a cross-sectional view of the flue as viewed in the direction a-a of fig. 4(a), wherein the spray gun is located in the middle of the side of the flue section and the absorption liquid feed pipe extends from the long side of the flue into and connects the spray heads. Absorbent introduced into flue per unit time and SO neutralized3The desired molar ratio of absorbent is about 2: 1.
After the operation is started, measuring SO in the flue gas at the downstream of the spray gun3The content is 3.1mg/Nm3. The sulfur trioxide removal rate reaches 96.5 percent.
After 1 hour, the SO in the flue gas at the upstream of the spray gun is measured again3The content of the smoke gas is increased to 106mg/Nm due to the working condition change of the equipment generating the smoke gas3. Based on the above measurements, the flow rate of the absorbent solution was adjusted to 1.8m by the control system3H, keeping the absorbent and SO introduced into the flue per unit time3Is about 2: 1.
Measuring SO in downstream flue gas of spray gun3The content is 2.8mg/Nm3. The sulfur trioxide removal rate reaches 97.4 percent.
Treated SO3The content is always kept atLow level, no corrosion to the air preheater and also compliance with emission standards.
Therefore, the embodiment also achieves an excellent sulfur trioxide removal effect by using a lower absorbent, and ensures the normal operation of the SCR denitration system.
Example 3
Similar to example 2, the sulfur trioxide removal apparatus shown in fig. 3 was used to perform sulfur trioxide removal on the flue gas of a flue gas cleaning facility including a selective catalytic reduction SCR denitration system. The difference is that the lance is arranged upstream of the ammonia injection device of the SCR system. In addition, a bag-type dust collector is arranged in front of the SCR reactor. Experimental results show that the flue gas entering the SCR system is fully desulfurized, and the problem that a catalyst in an SCR reactor is inactivated due to sulfur trioxide is completely avoided. Meanwhile, the temperature of the flue gas is not obviously reduced, and the SCR reaction can be normally carried out.
The apparatus and method of the present invention achieve excellent sulfur trioxide removal with lower absorbent usage by atomizing the spray absorbent solution.
It will be apparent to those skilled in the art that various changes and modifications may be made in the embodiments of the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.
Claims (13)
1. A sulfur trioxide removal apparatus for a flue gas purification facility, the flue gas purification facility comprising a Selective Catalytic Reduction (SCR) denitration system disposed in a flue, the sulfur trioxide removal apparatus comprising:
an absorbent dissolution tank configured to hold SO3An absorbent solution;
a compressed gas source configured to provide compressed gas; and
an atomizing spray unit in fluid communication with the absorbent dissolution tank and the compressed gas source and configured to utilizeThe compressed gas converts the SO3An absorbent solution is atomized and sprayed into the flue.
2. The sulfur trioxide removal apparatus of claim 1, characterized in that,
the absorbent dissolving tank comprises an absorbent solution heating device.
3. The sulfur trioxide removal apparatus of claim 1, wherein the atomizing injection unit is configured to at least direct the SO3An absorbent solution is injected into the flue upstream of the SCR denitration system.
4. The sulfur trioxide removal apparatus for flue gas cleaning facilities according to claim 1, wherein the atomizing injection unit comprises:
a buffer container;
an atomizing nozzle disposed in the buffer vessel, the atomizing nozzle in fluid communication with the sorbent dissolution tank and the compressed gas source, and configured to utilize the compressed gas to subject the SO to3Atomizing and spraying an absorbent solution into the buffer container; and
a grill unit disposed in the flue, the grill unit in fluid communication with the outlet of the buffer vessel.
5. The sulfur trioxide removal apparatus for flue gas cleaning facilities according to claim 1, wherein the atomizing injection unit comprises:
an atomizing nozzle disposed in the flue, the atomizing nozzle in fluid communication with the sorbent dissolution tank and the compressed gas source, and configured to utilize the compressed gas to subject the SO to3The sorbent solution is atomized and sprayed into the flue.
6. The sulfur trioxide removal apparatus for flue gas cleaning plants according to claim 5, characterized in that said sulfur trioxide removal apparatus further comprises an atomizing nozzle cooling device.
7. The sulfur trioxide removal apparatus for flue gas cleaning facilities of claim 6 wherein the atomizing nozzle cooling device comprises a cooling gas passageway.
8. The sulfur trioxide removal apparatus for a flue gas cleaning facility according to claim 1, characterized in that the sulfur trioxide removal apparatus comprises a control system configured to control the atomizing injection unit to differentiate the sorbent solution injection zones in the flue.
9. A sulfur trioxide removal method for a flue gas cleaning facility comprising a selective catalytic reduction, SCR, denitration system disposed in a flue, the method comprising:
using SO3Preparing SO from absorbent and water3The absorbent solution is a solution of an absorbent,
using compressed gas to mix the SO3An absorbent solution is atomized and sprayed into the flue.
10. The sulfur trioxide removal process according to claim 9, characterized in that,
the SO injected into the flue per unit time3SO in absorbent solution3The molar quantity of the absorbent is SO required for neutralizing sulfur trioxide in the flue gas flowing into the flue31 to 2 times the molar amount of absorbent.
11. The sulfur trioxide removal process according to claim 9, characterized in that,
subjecting the SO to3The sorbent solution is heated and injected into the flue upstream of the SCR denitration system.
12. The sulfur trioxide removal process according to claim 9, characterized in that,
the spray coverage of the spray in the flue is from 150% to 200%.
13. The sulfur trioxide removal process according to claim 9, characterized in that,
according to the SO of the flue gas3Content and flow field distribution of the flue gas in the flue, and the spraying subareas of the absorbent solution in the flue are differentiated.
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| CN105233656A (en) * | 2015-11-02 | 2016-01-13 | 中电投远达环保工程有限公司 | Process used for removing sulfur trioxide in flue gas of coal-fired power plant |
| CN205109379U (en) * | 2015-11-17 | 2016-03-30 | 中电投远达环保工程有限公司 | Sulfur trioxide's desorption system in coal fired power plant flue gas |
| CN105854557A (en) * | 2016-04-21 | 2016-08-17 | 上海迪夫格环境科技有限公司 | Method and device for evenly spraying alkali liquor to remove sulfur trioxide in exhaust gas |
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Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN105233656A (en) * | 2015-11-02 | 2016-01-13 | 中电投远达环保工程有限公司 | Process used for removing sulfur trioxide in flue gas of coal-fired power plant |
| CN205109379U (en) * | 2015-11-17 | 2016-03-30 | 中电投远达环保工程有限公司 | Sulfur trioxide's desorption system in coal fired power plant flue gas |
| CN105854557A (en) * | 2016-04-21 | 2016-08-17 | 上海迪夫格环境科技有限公司 | Method and device for evenly spraying alkali liquor to remove sulfur trioxide in exhaust gas |
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