CN115041000A - Industrial waste gas normal-pressure gas-phase oxidation liquid-phase reduction denitration method - Google Patents
Industrial waste gas normal-pressure gas-phase oxidation liquid-phase reduction denitration method Download PDFInfo
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- 239000007789 gas Substances 0.000 title claims abstract description 93
- 239000007791 liquid phase Substances 0.000 title claims abstract description 32
- 238000000034 method Methods 0.000 title claims abstract description 20
- 239000002440 industrial waste Substances 0.000 title claims abstract description 14
- 230000003647 oxidation Effects 0.000 title claims abstract description 13
- 238000007254 oxidation reaction Methods 0.000 title claims abstract description 13
- 239000012071 phase Substances 0.000 title claims abstract description 12
- 239000000243 solution Substances 0.000 claims abstract description 32
- 239000007864 aqueous solution Substances 0.000 claims abstract description 20
- 239000003638 chemical reducing agent Substances 0.000 claims abstract description 17
- 239000002912 waste gas Substances 0.000 claims abstract description 17
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 13
- 238000006243 chemical reaction Methods 0.000 claims abstract description 11
- 239000011734 sodium Substances 0.000 claims description 24
- XEVRDFDBXJMZFG-UHFFFAOYSA-N carbonyl dihydrazine Chemical compound NNC(=O)NN XEVRDFDBXJMZFG-UHFFFAOYSA-N 0.000 claims description 14
- GEHJYWRUCIMESM-UHFFFAOYSA-L sodium sulfite Chemical compound [Na+].[Na+].[O-]S([O-])=O GEHJYWRUCIMESM-UHFFFAOYSA-L 0.000 claims description 10
- 235000010265 sodium sulphite Nutrition 0.000 claims description 5
- 229910052979 sodium sulfide Inorganic materials 0.000 claims description 4
- GRVFOGOEDUUMBP-UHFFFAOYSA-N sodium sulfide (anhydrous) Chemical group [Na+].[Na+].[S-2] GRVFOGOEDUUMBP-UHFFFAOYSA-N 0.000 claims description 4
- RYYXDZDBXNUPOG-UHFFFAOYSA-N 4,5,6,7-tetrahydro-1,3-benzothiazole-2,6-diamine;dihydrochloride Chemical compound Cl.Cl.C1C(N)CCC2=C1SC(N)=N2 RYYXDZDBXNUPOG-UHFFFAOYSA-N 0.000 claims description 2
- JVBXVOWTABLYPX-UHFFFAOYSA-L sodium dithionite Chemical compound [Na+].[Na+].[O-]S(=O)S([O-])=O JVBXVOWTABLYPX-UHFFFAOYSA-L 0.000 claims description 2
- AKHNMLFCWUSKQB-UHFFFAOYSA-L sodium thiosulfate Chemical compound [Na+].[Na+].[O-]S([O-])(=O)=S AKHNMLFCWUSKQB-UHFFFAOYSA-L 0.000 claims description 2
- 235000019345 sodium thiosulphate Nutrition 0.000 claims description 2
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 claims 2
- 229910052799 carbon Inorganic materials 0.000 claims 1
- 239000001569 carbon dioxide Substances 0.000 claims 1
- 229910002092 carbon dioxide Inorganic materials 0.000 claims 1
- PMZURENOXWZQFD-UHFFFAOYSA-L Sodium Sulfate Chemical compound [Na+].[Na+].[O-]S([O-])(=O)=O PMZURENOXWZQFD-UHFFFAOYSA-L 0.000 abstract description 4
- 239000003344 environmental pollutant Substances 0.000 abstract description 3
- 231100000719 pollutant Toxicity 0.000 abstract description 3
- 238000010438 heat treatment Methods 0.000 abstract description 2
- 239000010446 mirabilite Substances 0.000 abstract description 2
- 229910052938 sodium sulfate Inorganic materials 0.000 abstract description 2
- 235000011152 sodium sulphate Nutrition 0.000 abstract description 2
- 239000007787 solid Substances 0.000 abstract description 2
- 229910000831 Steel Inorganic materials 0.000 description 16
- 239000010959 steel Substances 0.000 description 16
- 238000010521 absorption reaction Methods 0.000 description 13
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 description 8
- CBENFWSGALASAD-UHFFFAOYSA-N Ozone Chemical compound [O-][O+]=O CBENFWSGALASAD-UHFFFAOYSA-N 0.000 description 8
- 229910001882 dioxygen Inorganic materials 0.000 description 8
- 229910052751 metal Inorganic materials 0.000 description 8
- 239000002184 metal Substances 0.000 description 8
- 238000012856 packing Methods 0.000 description 7
- 238000002360 preparation method Methods 0.000 description 6
- 238000006722 reduction reaction Methods 0.000 description 6
- 239000007788 liquid Substances 0.000 description 5
- 238000005516 engineering process Methods 0.000 description 3
- 239000003513 alkali Substances 0.000 description 2
- 238000009472 formulation Methods 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 239000007800 oxidant agent Substances 0.000 description 2
- 230000001590 oxidative effect Effects 0.000 description 2
- SUKJFIGYRHOWBL-UHFFFAOYSA-N sodium hypochlorite Chemical compound [Na+].Cl[O-] SUKJFIGYRHOWBL-UHFFFAOYSA-N 0.000 description 2
- 238000010531 catalytic reduction reaction Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- -1 nitrogen-containing organic compound Chemical class 0.000 description 1
Classifications
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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
- B01D53/46—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
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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
- B01D53/76—Gas phase processes, e.g. by using aerosols
-
- 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
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2251/00—Reactants
- B01D2251/10—Oxidants
- B01D2251/104—Ozone
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2251/00—Reactants
- B01D2251/20—Reductants
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2251/00—Reactants
- B01D2251/20—Reductants
- B01D2251/206—Ammonium compounds
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2251/00—Reactants
- B01D2251/20—Reductants
- B01D2251/21—Organic compounds not provided for in groups B01D2251/206 or B01D2251/208
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A50/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE in human health protection, e.g. against extreme weather
- Y02A50/20—Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
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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)
- Dispersion Chemistry (AREA)
- Treating Waste Gases (AREA)
Abstract
The invention discloses a normal-pressure gas-phase oxidation liquid-phase reduction denitration method for industrial waste gas, which comprises the following steps of: controlling the temperature of the exhaust gas to a certain range; dissolving a liquid-phase reducing agent in water to obtain a liquid-phase reducing agent aqueous solution, and controlling the concentration, the pH value and the temperature of the solution at certain levels; mixing O with 3 Proportionally introducing it to the waste gas, mixing it with the components in waste gas, and reacting 3 Reaction with NO: o is 3 +NO→NO 2 +O 2 (ii) a Will react with O 3 Introducing the mixed gas obtained after the reaction into the aqueous solution of the liquid-phase reducing agent in proportion, fully mixing the gas and the solution for a certain time, and contacting the liquid-phase reducing agent and NO 2 Reaction takes place, NO 2 Is reduced to harmless N 2 Thereby achieving the purpose of removing NO. Compared with the traditional mainstream waste gas denitration method, the method has the advantages that: the denitration reaction is carried out at a low temperature of below 100 ℃, so that the outlet meets the requirement of ultra-low emission standard, and the denitration cost caused by heating waste gas is prevented from being greatly increased; capable of converting NOx to N 2 The discharge is carried out, and the environment is completely harmless to the atmospheric environment; the solution obtained after denitration can be evaporated, concentrated and crystallized to become solid sodium sulfate (mirabilite) for industrial utilization, and no secondary pollutant is generated.
Description
Technical Field
The invention belongs to the field of industrial waste gas treatment, and particularly relates to a normal-pressure gas-phase oxidation liquid-phase reduction denitration method for industrial waste gas.
Background
The reduction of the emission concentration and the emission amount of NOx in industrial waste gas is one of the most urgent tasks in the current and future period of the atmospheric pollution control field in China.
At present, the most popular exhaust gas denitration method is SCR dry denitration technology, which is to heat the exhaust gas to about 400 ℃ and then introduce NH 3 Catalytic reduction of harmful NOx in exhaust gas to harmless N 2 Thereby achieving the purpose of removing NOx. Because the exhaust gas is heated to a higher temperature, the process energy consumption is higher, and thus the denitration cost is higher.
Another exhaust gas denitration technique is a low-temperature wet denitration technique. The NO ratio in the waste gas reaches more than 95 percent, and the concentration is generally between 0.02 and 0.1V percent. On the one hand, NO is poorly soluble in water, has a solubility in water (at 50 ℃) of only 38mg/L and is NO 2 1/1000 or less; on the other hand, such low concentrations of NO are difficult to oxidize spontaneously to water-soluble NO 2 . Therefore, the conventional low-temperature wet denitration technology usually uses a liquid-phase strong oxidant such as HNO 3 、KMnO 4 、NaClO 2 、NaClO、H 2 O 2 、KBrO 3 、K 2 CrO 7 、(NH 4 ) 2 CrO 7 、NaCrO 4 The liquid phase oxidation of NO to NO is carried out in equal time 2 Then NO is added with alkali liquor 2 And (4) absorbing and removing. The technical method has three defects, namely, the consumed strong oxidant is too expensive, so that the denitration cost is too high; second, the alkali liquor used is to NO 2 The absorption is not thorough, and the concentration of NOx in the outlet waste gas is difficult to reach the standard of ultralow emission; thirdly, the absorption liquid obtained after removing NOx is difficult to treat and utilize, and a liquid phase pollutant is formed.
Disclosure of Invention
The invention aims to provide a liquid-phase reduction denitration method for atmospheric-pressure gas-phase oxidation of industrial waste gas, which aims to solve the problems in the background art.
In order to achieve the purpose, the invention provides the following technical scheme: a normal-pressure gas-phase oxidation liquid-phase reduction denitration method for industrial waste gas comprises the following steps:
s1, controlling the temperature of the waste gas to a certain range;
s2, dissolving the liquid-phase reducing agent in water to obtain a liquid-phase reducing agent aqueous solution, and controlling the concentration, pH and temperature of the solution at certain levels;
s3, mixing 3 Proportionally introducing it to the waste gas, mixing it with the components in waste gas, and reacting 3 Reaction with NO: o is 3 +NO→NO 2 +O 2 ；
S4, introducing the mixed gas obtained in the step S3 into a liquid phase reducing agent water solution in proportion, fully mixing and contacting the gas and the solution for a certain time, and mixing the liquid phase reducing agent and NO 2 Reaction takes place, NO 2 Is reduced to harmless N 2 Thereby achieving the purpose of removing NO.
In the S1, the waste gas temperature is less than or equal to 150 ℃, and preferably 20-100 ℃.
In the S2, the liquid-phase reducing agent is sodium sulfide (Na) 2 S), Carbohydrazide (CH) 6 N 4 O), sodium sulfite (Na) 2 SO 3 ) Sodium dithionite (Na) 2 S 4 O 2 ) Sodium thiosulfate (Na) 2 S 2 O 3 ) And thiourea dioxide (CH) 4 N 2 O 2 S), preferably sodium sulfide (Na) 2 S), carbohydrazide ((CH) 6 N 4 O) and sodium sulfite (Na) 2 SO 3 ) (ii) a The concentration of the liquid-phase reducing agent aqueous solution is not less than 0.16wt%, and preferably 0.5wt% to 9 wt%; the pH is not less than 6.0, preferably pH =7.0 to 12.5; the temperature is ≦ 100 ℃, preferably 30 ℃ to 60 ℃.
O introduced in S3 3 The molar ratio of the nitrogen-containing organic compound to NO in the waste gas is 0.9-1.1; the reaction is carried out for a predetermined time ≧ 0.5S, preferably 1S to 2S.
In the S4, the ratio of the liquid-phase reducing agent aqueous solution to the mixed gas is not less than 0.2L/m 3 Preferably 0.5 to 1.4; the mixing contact time is not less than 3S, and preferably 4S to 10S; the gas and solution are mixed thoroughly at atmospheric pressure.
Compared with the traditional mainstream waste gas denitration process technology, the industrial waste gas normal-pressure gas-phase oxidation liquid-phase reduction denitration method provided by the invention has the following obvious advantages:
(1) the denitration reaction is carried out at a low temperature of below 100 ℃, so that the denitration cost is prevented from being greatly increased due to heating of waste gas; (2) capable of converting NOx to N 2 The discharge is carried out, and the environment is completely harmless to the atmosphere;
(3) the solution obtained after denitration can be evaporated, concentrated and crystallized to become solid sodium sulfate (mirabilite) for industrial utilization, and no secondary pollutant is generated.
Detailed Description
The technical solutions in the embodiments of the present invention are clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Example 1:
the total flow rate of the steel cylinder gas is 1.3L/min, O 2 Concentration 15Vol%, NO concentration 300mg/Nm 3 The mixed gas of (3); making proper amount of O by using pure oxygen gas of steel cylinder and passing it through ozone generator 3 Adding an appropriate amount of O 3 Introducing the mixed gas to oxidize NO in the mixed gas into NO 2 The NO content is reduced to 20mg/Nm 3 (ii) a Preparation of Na 2 1200mL of aqueous solution with S concentrations of 0.16wt%, 0.32wt%, 0.65wt% and 1.3wt% respectively, evenly loading the aqueous solution into three absorption bottles, and controlling the temperature at 30 ℃; passing the above solution through O 3 The oxidized mixed gas is connected in series through the three absorption bottles, and the outlet gas corresponds to Na with the concentration from low to high 2 S solution with NOx content of 38 mg/Nm 3 、31 mg/Nm 3 、25 mg/Nm 3 、38 mg/Nm 3 And the corresponding denitration rates sequentially reach 92%, 94%, 95% and 92%.
Example 2:
the total flow rate of the steel cylinder gas is 1.3L/min, O 2 Concentration 15Vol% NO concentration 300mg/Nm 3 The mixed gas of (3); making pure oxygen gas from steel cylinder pass through ozone generator to obtain proper quantity of O 3 Adding an appropriate amount of O 3 Introducing the mixed gas to oxidize NO in the mixed gas into NO 2 The NO content is reduced to 20mg/Nm 3 (ii) a Preparation of Na 2 1200mL of aqueous solution with the S concentration of 0.16wt% and the pH of 6.27, 7.31 and 8.30 respectively is averagely filled into three absorption bottles, and the temperature is controlled at 30 ℃; passing the above solution through O 3 The oxidized mixed gas is connected in series through the three absorption bottles, and Na corresponding to the pH value from low to high is contained in the outlet gas 2 S solution with NOx content of 27 mg/Nm 3 、25 mg/Nm 3 、31 mg/Nm 3 And the corresponding denitration rates sequentially reach 95%, 95% and 94%.
Example 3:
the total flow rate of the steel cylinder gas is 1.3L/min, O 2 Concentration 15V% and NO concentration 300mg/Nm 3 The mixed gas of (3); making pure oxygen gas from steel cylinder pass through ozone generator to obtain proper quantity of O 3 Adding an appropriate amount of O 3 Introducing the mixed gas to oxidize NO in the mixed gas into NO 2 The NO content is reduced to 20mg/Nm 3 (ii) a Preparation of Na 2 1200mL of aqueous solution with the S concentration of 3.25wt% is respectively and averagely loaded into three absorption bottles, and the temperature of the solution in the absorption bottles is sequentially raised to 30 ℃, 50 ℃, 70 ℃ and 90 ℃ by a water bath kettle; passing the above solution through O 3 The oxidized mixed gas passes through the three absorption bottles in series, the temperature of the solution in the absorption bottle from low to high in the outlet gas is corresponding to 38 mg/Nm, and the NOx content is sequentially 3 、26mg/Nm 3 、26 mg/Nm 3 、26 mg/Nm 3 And the corresponding denitration rates sequentially reach 92%, 95% and 95%.
Example 4:
the total flow rate of the steel cylinder gas is 1.3L/min, O 2 The concentration of 15Vol% and the concentration of NO are 300mg/Nm 3 、600mg/Nm 3 、1000mg/Nm 3 The mixed gas of (3); making pure oxygen gas from steel cylinder pass through ozone generator to obtain proper quantity of O 3 Adding an appropriate amount of O 3 Introducing the mixed gas to oxidize NO in the mixed gas into NO 2 And the NO content is reduced to 20mg/Nm 3 (ii) a Preparation of Na 2 S concentration of 0.11200mL of 6wt% aqueous solution is respectively and evenly loaded into three absorption bottles, and the temperature of the solution in the absorption bottles is controlled to 30 ℃ by a water bath kettle; passing the above solution through O 3 The oxidized mixed gas passes through the three absorption bottles in series, the concentration of the NOx in the outlet gas is 37 mg/Nm in turn corresponding to the inlet mixed gas with the concentration of the NO from low to high 3 、26mg/Nm 3 、64 mg/Nm 3 And the corresponding denitration rates sequentially reach 93%, 98% and 97%.
Example 5:
the total flow rate of the steel cylinder gas is 1.3L/min, O 2 Concentration 15Vol% and NO concentration 300mg/Nm 3 The mixed gas of (3); making proper amount of O by using pure oxygen gas of steel cylinder and passing it through ozone generator 3 Adding an appropriate amount of O 3 Introducing the mixed gas to oxidize NO in the mixed gas into NO 2 And the NO content is reduced to 20mg/Nm 3 (ii) a Preparation of Na 2 500mL of an aqueous solution having an S concentration of 1.3wt% and a pH =12, the temperature of the solution being controlled to 30 ℃ with a water bath; passing the above solution through O 3 The oxidized mixed gas flows through the metal packing column from bottom to top to lead Na 2 The S aqueous solution is dripped into the metal packing column from top to bottom to ensure that the gas-liquid contact time reaches 10.5S and the liquid-gas ratio reaches 0.31L/m respectively 3 And 0.38L/m 3 The NOx content in the outlet gas is 40 mg/Nm corresponding to the liquid-gas ratio from low to high 3 、22mg/Nm 3 And the corresponding denitration rates reach 92% and 96% in sequence.
Example 6:
the total flow rate of the steel cylinder gas is 1.5L/min, 2.4L/min and O 2 Concentration 15Vol% and NO concentration 300mg/Nm 3 The mixed gas of (3); making pure oxygen gas from steel cylinder pass through ozone generator to obtain proper quantity of O 3 Adding an appropriate amount of O 3 Introducing the mixed gas to oxidize NO in the mixed gas into NO 2 The NO content is reduced to 20mg/Nm 3 (ii) a Preparation of Na 2 500mL of an aqueous solution having an S concentration of 0.32wt% and a pH =12.6, the temperature of the solution being controlled to 30 ℃ with a water bath; passing the above solution through O 3 The oxidized mixed gas flows through the metal packing column from bottom to top to lead Na 2 The S aqueous solution is dripped into the metal packing column from top to bottom to make the liquid-gas ratio reach 0.5L/m 3 Bringing the gas and the liquid into contact with each otherThe time reaches 5.65S and 3.53S respectively, the NOx content in the outlet gas is 39 mg/Nm respectively corresponding to the gas-liquid contact time from long to short 3 、40mg/Nm 3 And the corresponding denitration rates reach 93 percent and 92 percent in sequence.
Example 7:
the total flow rate of the steel cylinder gas is 2.5L/min and O 2 Concentration 15Vol% and NO concentration 300mg/Nm 3 The mixed gas of (3); making pure oxygen gas from steel cylinder pass through ozone generator to obtain proper quantity of O 3 Adding an appropriate amount of O 3 Introducing the mixed gas to oxidize NO in the mixed gas into NO 2 The NO content is reduced to 20mg/Nm 3 (ii) a Formulation pH =12.5 and Carbohydrazide (CH) 6 N 4 O) water solutions with the concentrations of 0.5wt% and 1.0wt% respectively, and controlling the temperature of the solution to 30 ℃ by using a water bath kettle; passing the above solution through O 3 The oxidized mixed gas flows through a metal packing column from bottom to top to cause Carbohydrazide (CH) 6 N 4 O) the aqueous solution was dropped into the metal packed column from the top to the bottom so that the liquid-gas ratios became 0.3L/m, respectively 3 、0.2 L/m 3 The gas-liquid contact time is 3.39S, the NOx content in the outlet gas respectively reaches 44 mg/Nm corresponding to the solution concentration from low to high and the liquid-gas ratio from high to low 3 、30mg/Nm 3 And the corresponding denitration rates reach 90% and 94% in sequence.
Example 8:
the total flow rate of the steel cylinder gas is 2.0L/min and O 2 Concentration 15Vol% and NO concentration 300mg/Nm 3 The mixed gas of (3); making pure oxygen gas from steel cylinder pass through ozone generator to obtain proper quantity of O 3 Adding an appropriate amount of O 3 Introducing the mixed gas to oxidize NO in the mixed gas into NO 2 The NO content is reduced to 20mg/Nm 3 (ii) a Formulation pH =12.5, sodium sulfite (Na) 2 SO 3 ) Controlling the temperature of the aqueous solution with the concentration of 2.8wt%, 6.8wt% and 9.0wt% to 30 ℃ by using a water bath kettle; passing the above solution through O 3 The oxidized mixed gas flows through the metal packing column from bottom to top to lead Na 2 SO 3 The aqueous solution is dripped into the metal packing column from top to bottom to make the liquid-gas ratio reach 1.4L/m 3 、0.7 L/m 3 、0.5 L/m 3 Connect gas and liquidThe contact time reaches 10S, the NOx content of the outlet gas reaches 44 mg/Nm respectively corresponding to the solution concentration from low to high 3 、32mg/Nm 3 、40mg/Nm 3 And the corresponding denitration rates reach 91%, 93% and 92% in sequence.
Claims (5)
1. A liquid phase reduction denitration method for atmospheric pressure gas phase oxidation of industrial waste gas is characterized by comprising the following steps:
a, controlling the temperature of the waste gas to a certain range;
b, dissolving a liquid-phase reducing agent in water to obtain a liquid-phase reducing agent aqueous solution, and controlling the concentration, pH and temperature of the solution to certain levels;
c is to O 3 Proportionally introducing it to the waste gas, mixing it with the components in waste gas, and reacting 3 Reaction with NO: o is 3 +NO→NO 2 +O 2 ；
D, introducing the mixed gas obtained in the step C into a liquid-phase reducing agent aqueous solution in proportion, fully mixing and contacting the gas and the solution for a certain time, and mixing the liquid-phase reducing agent and NO 2 Reaction takes place, NO 2 Is reduced to harmless N 2 Thereby achieving the purpose of removing NOx.
2. The atmospheric pressure gas phase oxidation liquid phase reduction denitration method for the industrial waste gas as set forth in claim 1, characterized in that: in the step A, the temperature of the waste gas is controlled to be less than or equal to 150 ℃, and preferably 20-100 ℃.
3. The atmospheric pressure gas phase oxidation liquid phase reduction denitration method for the industrial waste gas as set forth in claim 1, characterized in that: in the B, the liquid-phase reducing agent is sodium sulfide (Na) 2 S), Carbohydrazide (CH) 6 N 4 O), sodium sulfite (Na) 2 SO 3 ) Sodium dithionite (Na) 2 S 4 O 2 ) Sodium thiosulfate (Na) 2 S 2 O 3 ) And thiourea dioxide (CH) 4 N 2 O 2 S), preferably sodium sulfide (Na) 2 S), Carbohydrazide (CH) 6 N 4 O）And sodium sulfite (Na) 2 SO 3 ) (ii) a The concentration of the solution is not less than 0.16wt%, preferably 0.5wt% to 9 wt%; the pH is not less than 6.0, preferably pH = 7.0-12.5; the temperature is less than or equal to 100 ℃, and preferably ranges from 30 ℃ to 60 ℃.
4. The atmospheric pressure gas phase oxidation liquid phase reduction denitration method for the industrial waste gas as set forth in claim 1, characterized in that: in said C, O is introduced 3 The molar ratio of the carbon dioxide to NO in the exhaust gas is 0.9-1.1, and the mixing reaction is carried out for a certain time ≧ 0.5S, preferably 1S-2S.
5. The atmospheric pressure gas phase oxidation liquid phase reduction denitration method for the industrial waste gas as set forth in claim 1, characterized in that: in the step D, the ratio of the liquid-phase reducing agent aqueous solution to the mixed gas is not less than 0.2L/m 3 Preferably 0.5 to 1.4L/m 3 (ii) a The mixing and contacting are carried out for a certain time ≧ 3S, preferably 4S-10S; the gas and solution are mixed thoroughly at atmospheric pressure.
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| CN202210870978.8A CN115041000A (en) | 2022-07-23 | 2022-07-23 | Industrial waste gas normal-pressure gas-phase oxidation liquid-phase reduction denitration method |
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| CN202210870978.8A CN115041000A (en) | 2022-07-23 | 2022-07-23 | Industrial waste gas normal-pressure gas-phase oxidation liquid-phase reduction denitration method |
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2022
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Application publication date: 20220913 |