CN111097285A - Method for removing NOx by sulfuric acid device - Google Patents
Method for removing NOx by sulfuric acid device Download PDFInfo
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- CN111097285A CN111097285A CN201811266264.6A CN201811266264A CN111097285A CN 111097285 A CN111097285 A CN 111097285A CN 201811266264 A CN201811266264 A CN 201811266264A CN 111097285 A CN111097285 A CN 111097285A
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- converter
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- flue gas
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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
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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
- B01D2251/2062—Ammonia
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- 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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- Environmental & Geological Engineering (AREA)
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- Oil, Petroleum & Natural Gas (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Exhaust Gas Treatment By Means Of Catalyst (AREA)
Abstract
The invention discloses a method for removing NOx by a sulfuric acid device. Belongs to the environmental protection technology in the field of acid making. The flue gas enters the converter after being heated by the heat exchanger from the first absorption tower, liquid ammonia is atomized under the action of compressed air in an atomizing spray gun and then enters the main flue gas pipeline to be mixed with the liquid ammonia, the mixed gas uniformly enters a converter bed layer under the action of a distributor at the inlet of the converter, firstly passes through a denitration catalyst layer and then enters a conversion catalyst layer after passing through heat-resistant ceramic balls, the high-temperature flue gas after reaction is subjected to heat transfer through a subsequent heat exchanger and then enters the second absorption tower to be absorbed for acid production, and the tail gas reaches the standard and is discharged. The method and the device have reliable operation, the removal rate of NOx reaches more than 90 percent, and the escape concentration of ammonia is lower than 1mg/Nm3And the tail gas reaches the standard and is discharged.
Description
Technical Field
The invention belongs to the environmental protection technology in the field of acid making, and relates to a method for removing NOx by a sulfuric acid device.
Background
At present, the concentration requirement of NOx in the tail gas emission of the acid making device is less than or equal to 100mg/Nm3The traditional low-nitrogen combustion technology can not meet the requirements, particularly in the process of preparing acid from ammonia-containing acidic gas, the ammonia content in the raw materials is large, and the high temperature in the incinerator reaches about 1100 ℃, so that the concentration of nitrogen oxides in process flue gas is very high and even exceeds 1000mg/Nm3And the denitration efficiency of the subsequent purification section and the tail gas washing section is very low, so that the content of nitrogen oxides in the tail gas is seriously over-standard, and the quality of a sulfuric acid product is influenced.
Disclosure of Invention
The invention aims to provide a method for removing NOx by a sulfuric acid device, aiming at the defects in the prior art.
The main technical scheme of the invention is as follows: a process for removing NOx from sulfuric acid apparatus includes such steps as heating the fume in one absorption tower by heat exchanger, introducing it into converter, atomizing liquid ammonia by atomizing spray gun, introducing the atomized liquid ammonia into main fume pipeline, mixing, introducing the mixed gas in the bed layer of converter, passing through denitration catalyst layer, heat-resistant ceramic balls, converting catalyst layer, removing heat of high-temp fume, and absorbing by two absorption towers.
Generally, the removal apparatus employed in the process of the present invention comprises: the device comprises an inlet heat exchanger, a liquid ammonia atomization spray gun, a converter gas distributor, a converter, a denitration catalyst bed layer, a heat-resistant ceramic ball, a vanadium catalyst bed layer and an outlet heat exchanger.
In order to ensure the sufficient atomization of the liquid ammonia, the pressure of the compressed air is controlled to be 0.3-0.5 MPa.
In order to ensure the sufficient reaction of ammonia gas and NOx, the injection amount of liquid ammonia needs to be controlled according to the content of NOx in the process flue gas, and generally, the volume ratio of ammonia gas to nitric oxide is controlled to be 0.5-0.8.
And in order to ensure good gas distribution, a gas distributor is arranged at the inlet of the converter, and the opening rate of the distribution plate is 50-60%. The inclination angle is 50-70 degrees.
The temperature range of the flue gas from the first absorption tower after heat exchange is 390-420 ℃, and the temperature range of the NOx removal reaction and the vanadium catalyst reaction is considered.
The height of the catalyst in the denitration reaction section is 200-400 mm, the height of the catalyst in the vanadium catalyst reaction section is 500-800 mm, and the height of the middle heat-resistant porcelain ball is 50 mm.
In order to facilitate loading and unloading, stainless steel wire meshes are laid on the upper surface and the lower surface of the heat-resistant porcelain ball, the diameter of each steel wire is 2-3 mm, and the distance between the steel wires is 6-8 mm.
Preferably, the content of NOx in the flue gas is analyzed on line, the escape rate of ammonia is monitored on line, and the injection amount of liquid ammonia is automatically adjusted.
The vanadium catalyst of the invention has higher reaction activity and lower light-off temperature.
The method and the device have reliable operation, the removal rate of NOx reaches more than 90 percent, and the escape concentration of ammonia is lower than 1mg/Nm3And the tail gas reaches the standard and is discharged.
Drawings
FIG. 1 is a schematic process flow diagram of a method according to an embodiment of the present invention.
In the figure, 1-inlet heat exchanger, 2-liquid ammonia atomization spray gun, 3-converter gas distributor, 4-converter, 5-denitration catalyst bed layer, 6-heat-resistant ceramic ball, 7-vanadium catalyst bed layer and 8-outlet heat exchanger.
Detailed Description
The present invention will be described in detail below with reference to examples and the accompanying drawings.
Example 1
As shown in the figure, the amount of process flue gas from one absorption tower is 7260Nm3After the temperature of the flue gas is raised to 395 ℃ by a heat exchanger at 55 ℃ and 12KPa, the flue gas enters a converter, and the content of each component of the flue gas, namely SO2：0.8%；O2：5.2%；CO2：6.5%；N2：87.4%；NOx：800mg/ Nm3(ii) a 1.7kg/h of liquid ammonia is atomized under the action of 0.5MPa compressed air in an atomizing spray gun and then enters a main flue gas pipeline to be mixed with the liquid ammonia, mixed gas uniformly enters a converter bed layer under the action of a distributor at an inlet of the converter and then passes through a denitration catalyst layer, the removal rate of NOx reaches more than 90 percent, and the escape concentration of ammonia is 1mg/Nm3. Then the reaction product enters a conversion catalyst layer after passing through a heat-resistant ceramic ball with the thickness of 50mm, the temperature of the high-temperature flue gas after reaction reaches 410 ℃, and the reaction product is subjected to heat exchange by a subsequent heat exchanger to 140 ℃ and then is sent to a secondary absorption tower to absorb acid. The concentration of NOx in tail gas emission is 40 mg/Nm3And discharging after reaching the standard.
Example 2
As shown in the figure, the amount of process flue gas from one absorption tower is 28500Nm3After the temperature of the flue gas is raised to 410 ℃ by a heat exchanger at 55 ℃ and 14KPa, the flue gas enters a converter, and the content of each component of the flue gas, namely SO2：1.1%；O2：4.8%； N2：94%；NOx：600mg/ Nm3(ii) a 5.1kg/h of liquid ammonia is atomized under the action of 0.4MPa compressed air in an atomizing spray gun and then enters a main flue gas pipeline to be mixed with the liquid ammonia, mixed gas uniformly enters a converter bed layer under the action of a distributor at an inlet of the converter and then passes through a denitration catalyst layer with the thickness of 200mm, the removal rate of NOx reaches more than 90 percent, and the ammonia escape concentration is 1mg/Nm3. Then enters a conversion catalyst layer with the thickness of 700mm after passing through a heat-resistant porcelain ball with the thickness of 50mm, the temperature of the high-temperature flue gas after reaction reaches 419 ℃, and the high-temperature flue gas is subjected to heat exchange by a subsequent heat exchanger to 160 ℃ and then enters a secondary absorption tower to absorb acid. The concentration of NOx in tail gas emission is 56 mg/Nm3And discharging after reaching the standard.
Example 3
As shown in the figure, the amount of process flue gas from the absorption tower is 51000Nm3Heating to 405 ℃ at 50 ℃ and 14KPa through a heat exchanger, and then entering a converter, wherein the content of each component of the flue gas, SO2：0.8%；O2：5%； N2：94.1%；NOx：630mg/ Nm3(ii) a Liquid ammonia of 9.2kg/h is atomized under the action of 0.45MPa compressed air in an atomizing spray gun and then enters a main flue gas pipeline to be mixed with the liquid ammonia, mixed gas uniformly enters a converter bed layer under the action of a distributor at the inlet of the converter and then passes through a denitration catalyst layer, the removal rate of NOx reaches more than 90 percent, and the escape concentration of ammonia is 1mg/Nm3. Then enters a conversion catalyst layer after passing through a heat-resistant porcelain ball, stainless steel wire meshes are laid on the upper surface and the lower surface of the heat-resistant porcelain ball, the temperature of the high-temperature flue gas after reaction reaches 420 ℃, and the high-temperature flue gas is subjected to heat exchange by a subsequent heat exchanger to 165 ℃ and then enters a secondary absorption tower to be absorbed to prepare acid. The concentration of NOx in tail gas emission is 60 mg/Nm3And discharging after reaching the standard.
The above description is only a preferred example of the present invention, and it should be noted that other equivalent modifications and improvements can be made by those skilled in the art based on the common general knowledge in the field in the technical teaching provided by the present invention, and the protection scope of the present invention should also be considered.
Claims (10)
1. A method for removing NOx from sulfuric acid device is characterized in that process flue gas is heated by a heat exchanger from an absorption tower and then enters a converter, liquid ammonia is atomized under the action of compressed air in an atomizing spray gun and then enters a main flue gas pipeline to be mixed with the liquid ammonia, mixed gas uniformly enters a bed layer of the converter under the action of a distributor at the inlet of the converter, the mixed gas firstly passes through a denitration catalyst layer and then enters a conversion catalyst layer after passing through heat-resistant ceramic balls, the high-temperature flue gas after reaction is subjected to heat transfer through a subsequent heat exchanger and then enters a secondary absorption tower to be absorbed for acid production.
2. A method according to claim 1 or 2, characterized in that the removal device used comprises: the device comprises an inlet heat exchanger, a liquid ammonia atomization spray gun, a converter gas distributor, a converter, a denitration catalyst bed layer, a heat-resistant ceramic ball, a vanadium catalyst bed layer and an outlet heat exchanger.
3. The method according to claim 1 or 2, characterized in that the liquid ammonia atomization lance controls the injection amount of liquid ammonia according to the NOx content in the process flue gas: the volume ratio of the ammonia gas to the nitrogen oxide is controlled to be 0.5-0.8, and the pressure of the compressed air is controlled to be 0.3-0.5 MPa.
4. The method according to claim 1 or 2, wherein the height of the catalyst in the denitration reaction section is 200-400 mm, the height of the catalyst in the vanadium catalyst reaction section is 500-800 mm, and the height of the middle heat-resistant porcelain ball is 50 mm.
5. The method according to claim 1 or 2, wherein a gas distributor is arranged at the inlet of the converter, the aperture ratio of a distribution plate is 50-60%, and the inclination angle is 50-70 °.
6. The method according to claim 1 or 2, characterized in that in the converter: stainless steel wire meshes are laid on the upper surface and the lower surface of the heat-resistant porcelain ball, the diameter of each steel wire is 2-3 mm, and the distance between the steel wires is 6-8 mm.
7. The method as claimed in claim 1 or 2, wherein the temperature range of the flue gas from the first absorption tower after heat exchange is 390 to 420 ℃, and the temperature range of the NOx removal reaction and the vanadium catalyst reaction is considered.
8. The method according to claim 1 or 2, characterized in that the content of NOx in the flue gas is analyzed on line, the escape rate of ammonia is monitored on line, and the injection amount of liquid ammonia is automatically adjusted.
9. The method of claim 1 or 2, wherein the vanadium catalyst has a higher reactivity and a lower light-off temperature.
10. The method according to claim 1 or 2, characterized in thatCharacterized in that the removal rate of NOx reaches more than 90 percent, and the escape concentration of ammonia is lower than 1mg/Nm3And the tail gas reaches the standard and is discharged.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811266264.6A CN111097285A (en) | 2018-10-29 | 2018-10-29 | Method for removing NOx by sulfuric acid device |
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| CN201811266264.6A CN111097285A (en) | 2018-10-29 | 2018-10-29 | Method for removing NOx by sulfuric acid device |
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| CN111097285A true CN111097285A (en) | 2020-05-05 |
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| CN201811266264.6A Pending CN111097285A (en) | 2018-10-29 | 2018-10-29 | Method for removing NOx by sulfuric acid device |
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Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN203030188U (en) * | 2012-12-21 | 2013-07-03 | 邵志辉 | Multi-stage catalytic adsorption reactor |
| CN105417501A (en) * | 2014-09-23 | 2016-03-23 | 中国石油化工股份有限公司 | Cooling method for blower in sulfuric acid production |
| CN106076112A (en) * | 2016-06-03 | 2016-11-09 | 阳煤集团深州化工有限公司 | One removes N simultaneously2o and NOxmethod |
| CN106731826A (en) * | 2016-12-27 | 2017-05-31 | 江苏科瑞工程设计有限公司 | One kind reduces NO in spent acid cracker tail gasXThe method of concentration |
| CN106915731A (en) * | 2017-04-14 | 2017-07-04 | 双盾环境科技有限公司 | A kind of adjustable application inertia catalyst treatment high concentration SO2Flue gas produces SO3The device of gas |
| CN107261804A (en) * | 2017-07-21 | 2017-10-20 | 中石化南京工程有限公司 | A kind of NO removed in sulfuric acid flue gasxDevice and method |
| CN108970395A (en) * | 2018-07-30 | 2018-12-11 | 江苏科瑞工程设计有限公司 | A kind of method of sulfuric acid apparatus removing NOx |
-
2018
- 2018-10-29 CN CN201811266264.6A patent/CN111097285A/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN203030188U (en) * | 2012-12-21 | 2013-07-03 | 邵志辉 | Multi-stage catalytic adsorption reactor |
| CN105417501A (en) * | 2014-09-23 | 2016-03-23 | 中国石油化工股份有限公司 | Cooling method for blower in sulfuric acid production |
| CN106076112A (en) * | 2016-06-03 | 2016-11-09 | 阳煤集团深州化工有限公司 | One removes N simultaneously2o and NOxmethod |
| CN106731826A (en) * | 2016-12-27 | 2017-05-31 | 江苏科瑞工程设计有限公司 | One kind reduces NO in spent acid cracker tail gasXThe method of concentration |
| CN106915731A (en) * | 2017-04-14 | 2017-07-04 | 双盾环境科技有限公司 | A kind of adjustable application inertia catalyst treatment high concentration SO2Flue gas produces SO3The device of gas |
| CN107261804A (en) * | 2017-07-21 | 2017-10-20 | 中石化南京工程有限公司 | A kind of NO removed in sulfuric acid flue gasxDevice and method |
| CN108970395A (en) * | 2018-07-30 | 2018-12-11 | 江苏科瑞工程设计有限公司 | A kind of method of sulfuric acid apparatus removing NOx |
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Application publication date: 20200505 |