CN114466690A - Selective catalytic reduction method and selective catalytic reduction system - Google Patents
Selective catalytic reduction method and selective catalytic reduction system Download PDFInfo
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- 239000007789 gas Substances 0.000 claims abstract description 85
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 claims abstract description 75
- 229910017604 nitric acid Inorganic materials 0.000 claims abstract description 75
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- 239000000654 additive Substances 0.000 claims description 16
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- 229910002651 NO3 Inorganic materials 0.000 claims description 8
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 claims description 8
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 claims description 7
- 235000011114 ammonium hydroxide Nutrition 0.000 claims description 7
- 231100000572 poisoning Toxicity 0.000 claims description 7
- 230000000607 poisoning effect Effects 0.000 claims description 7
- 229910052717 sulfur Inorganic materials 0.000 claims description 7
- 239000011593 sulfur Substances 0.000 claims description 7
- BIGPRXCJEDHCLP-UHFFFAOYSA-N ammonium bisulfate Chemical compound [NH4+].OS([O-])(=O)=O BIGPRXCJEDHCLP-UHFFFAOYSA-N 0.000 claims description 6
- WTHDKMILWLGDKL-UHFFFAOYSA-N urea;hydrate Chemical group O.NC(N)=O WTHDKMILWLGDKL-UHFFFAOYSA-N 0.000 claims description 6
- 229910052921 ammonium sulfate Inorganic materials 0.000 claims description 3
- 235000011130 ammonium sulphate Nutrition 0.000 claims description 3
- 229910000069 nitrogen hydride Inorganic materials 0.000 claims description 3
- MGWGWNFMUOTEHG-UHFFFAOYSA-N 4-(3,5-dimethylphenyl)-1,3-thiazol-2-amine Chemical compound CC1=CC(C)=CC(C=2N=C(N)SC=2)=C1 MGWGWNFMUOTEHG-UHFFFAOYSA-N 0.000 claims description 2
- 229910002089 NOx Inorganic materials 0.000 claims description 2
- 238000000354 decomposition reaction Methods 0.000 claims description 2
- 238000002156 mixing Methods 0.000 claims description 2
- JCXJVPUVTGWSNB-UHFFFAOYSA-N nitrogen dioxide Inorganic materials O=[N]=O JCXJVPUVTGWSNB-UHFFFAOYSA-N 0.000 claims description 2
- 238000005507 spraying Methods 0.000 claims 1
- 239000003638 chemical reducing agent Substances 0.000 abstract description 14
- 230000003197 catalytic effect Effects 0.000 abstract description 3
- 238000002474 experimental method Methods 0.000 description 18
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 14
- 230000009849 deactivation Effects 0.000 description 14
- 230000000694 effects Effects 0.000 description 9
- 230000000052 comparative effect Effects 0.000 description 8
- 230000002779 inactivation Effects 0.000 description 8
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 description 7
- 239000004408 titanium dioxide Substances 0.000 description 6
- 239000007864 aqueous solution Substances 0.000 description 5
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- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 2
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- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- WWILHZQYNPQALT-UHFFFAOYSA-N 2-methyl-2-morpholin-4-ylpropanal Chemical compound O=CC(C)(C)N1CCOCC1 WWILHZQYNPQALT-UHFFFAOYSA-N 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 239000005864 Sulphur Substances 0.000 description 1
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Chemical compound NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 description 1
- XHCLAFWTIXFWPH-UHFFFAOYSA-N [O-2].[O-2].[O-2].[O-2].[O-2].[V+5].[V+5] Chemical compound [O-2].[O-2].[O-2].[O-2].[O-2].[V+5].[V+5] XHCLAFWTIXFWPH-UHFFFAOYSA-N 0.000 description 1
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- GNTDGMZSJNCJKK-UHFFFAOYSA-N vanadium(V) oxide Substances O=[V](=O)O[V](=O)=O GNTDGMZSJNCJKK-UHFFFAOYSA-N 0.000 description 1
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/92—Chemical or biological purification of waste gases of engine exhaust gases
- B01D53/94—Chemical or biological purification of waste gases of engine exhaust gases by catalytic processes
- B01D53/9404—Removing only nitrogen compounds
- B01D53/9409—Nitrogen oxides
- B01D53/9413—Processes characterised by a specific catalyst
- B01D53/9418—Processes characterised by a specific catalyst for removing nitrogen oxides by selective catalytic reduction [SCR] using a reducing agent in a lean exhaust gas
-
- 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
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2257/00—Components to be removed
- B01D2257/40—Nitrogen compounds
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Analytical Chemistry (AREA)
- Health & Medical Sciences (AREA)
- Biomedical Technology (AREA)
- Environmental & Geological Engineering (AREA)
- Combustion & Propulsion (AREA)
- General Chemical & Material Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Exhaust Gas Treatment By Means Of Catalyst (AREA)
- Catalysts (AREA)
- Exhaust Gas After Treatment (AREA)
Abstract
The present invention relates to a selective catalytic reduction method and a selective catalytic reduction system for injecting an ammonia reducing agent and a nitric acid supply source into a process gas containing nitrogen monoxide (NO) and supplying the same to a selective catalytic reactor, which can not only greatly improve the denitrification efficiency but also reduce SO2The resulting denitrification performance is reduced and the performance of the SCR process with reduced performance is improved in situ, thereby maintaining performance and improving process efficiency.
Description
Technical Field
The invention relates to a method for supplying an ammonia reducing agent to a selective catalytic reduction reactor together with a nitric acid supply sourceA selective catalytic reduction method and a selective catalytic reduction system which greatly improve the denitrification efficiency. Furthermore, it relates to a method for reducing SO2The denitrification performance is reduced and the performance of a Selective Catalytic Reduction (SCR) process and a catalyst having low performance is improved in situ, thereby maintaining the performance and improving the process efficiency.
Background
Nitrogen Oxides (NO)X) Primarily generated when fossil fuels are burned, produced from mobile sources such as ships or automobiles, or stationary sources such as power plants or incinerators. Such nitrogen oxides are considered to be one of the main causes of atmospheric pollution due to acid rain and haze formation, and recently, restrictions on atmospheric environmental pollution have become increasingly strict, and in this regard, a great deal of research is being conducted to reduce nitrogen oxides by using a reducing agent.
Among them, as a method for removing nitrogen oxides discharged from a stationary source, titanium dioxide (Titania, TiO) using ammonia or the like as a reducing agent is widely used2) Support and vanadium (V) oxide2O5) Used as a denitrification catalyst for activating the catalyst component.
In the denitrification catalyst of titanium dioxide (titanium, hereinafter, used in combination with "titanium dioxide") using ammonia as a reducing agent, since the denitrification efficiency is excellent at 350 ℃ or higher, a method of artificially raising the exhaust gas temperature is used when the catalyst is set at an exhaust gas temperature of 350 ℃ or higher or when the catalyst is used at a low temperature of 350 ℃ or lower.
However, ammonia has a problem that it is difficult to have sufficient denitrification efficiency at a temperature of less than 350 ℃.
Disclosure of Invention
Technical problem
The present invention is intended to solve the problems described above, and is to provide a novel method and system capable of improving the denitrification efficiency of an ammonia reducing agent.
Technical scheme
To achieve the above object, the present invention provides a selective catalytic reduction reaction method as a selectiveA catalytic reduction reaction process comprising: mixed injection of ammonia (NH) into a process gas containing Nitric Oxide (NO)3) A supply source and a nitric acid supply source; and a step of maintaining the temperature of the reactor into which the ammonia supply source and the nitric acid supply source are injected in the range of 200 ℃ to350 ℃.
Further, the present invention provides a selective catalytic reduction reaction system as a selective catalytic reduction reaction method, including: an exhaust gas reactor including an exhaust gas containing Nitric Oxide (NO) equipped therein with a catalyst for a selective catalytic reduction reaction; a mixed gas injection line for injecting an ammonia supply and a nitric acid supply into the exhaust gas reactor; and a first control portion for controlling injection amounts of the ammonia supply source and the nitric acid supply source, wherein the temperature in the exhaust gas reactor into which the ammonia supply source and the nitric acid supply source are injected is maintained in a range of 200 ℃ to350 ℃.
Technical effects
According to the selective catalytic reduction method and the selective catalytic reduction system of the present invention, the nitric acid supply source and the original reducing agent can be injected into the conventional SCR process together as necessary, and not only can the denitrification effect be sufficiently exerted even at a relatively low temperature, but also the SO can be reduced2The denitrification performance is reduced, and the performance of the SCR process with low performance is improved in situ (in-situ), so that the method has the advantages of maintaining the performance and improving the process efficiency.
Drawings
Fig. 1 is a sequence diagram illustrating a selective catalytic reduction reaction method according to the present invention.
Fig. 2 is a schematic diagram of a selective catalytic reduction reaction system according to the present invention.
Fig. 3 is a schematic diagram of a selective catalytic reduction reaction system according to the present invention.
FIG. 4 is SO illustrating a selective catalytic reduction reaction method according to an embodiment of the present invention2Graph of the results of the inactivation experiment.
Fig. 5 is a graph illustrating deactivation inhibiting performance after additional injection of ammonium nitrate in the selective catalytic reduction reaction method according to an embodiment of the present invention.
FIG. 6 is SO illustrating a selective catalytic reduction reaction method according to an embodiment of the present invention2Graph of the results of the deactivation experiments, shown at SO2Time-varying NO and SO in constant temperature continuous injection experiments2The concentration was varied (example 1).
FIG. 7 is SO illustrating a selective catalytic reduction reaction method according to an embodiment of the present invention2Graph of the results of the deactivation experiments, shown at SO2Time-varying NO and SO in constant temperature continuous injection experiments2The concentration was varied (example 3).
Best mode for carrying out the invention
While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail.
However, the present invention is not limited to the specific embodiments, and all modifications, equivalents, and alternatives included in the spirit and technical scope of the present invention are understood to be included. In explaining the present invention, when it is judged that the detailed description of the related known art may obscure the gist of the present invention, the detailed description is omitted.
The terminology used in the description presented herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. Expressions in the singular include expressions in the plural as long as the context does not explicitly indicate a difference.
In the present invention, the terms "comprising" or "having" are to be understood as specifying the presence of the features, numerals, steps, actions, constituent elements, components or combinations thereof described in the specification, and do not preclude the possibility of the presence or addition of one or more other features or numerals, steps, actions, constituent elements, components or combinations thereof.
The present invention relates to a selective catalytic reduction method and a selective catalytic reduction system.
Conventionally, in the case of a titanium dioxide (titanium, hereinafter, used in combination with "titanium dioxide") type denitrification catalyst using ammonia as a reducing agent, since the denitrification efficiency is excellent at 350 ℃ or higher, a method of artificially raising the exhaust gas temperature is used when the catalyst is set at an exhaust gas temperature of 350 ℃ or higher or when the catalyst is used at a low temperature of 350 ℃ or lower. That is, ammonia has a problem that it is difficult to have sufficient denitrification efficiency at a temperature of less than 350 ℃.
Accordingly, the present invention relates to a selective catalytic reduction method and a selective reduction system, and provides a selective catalytic reduction method and a selective reduction system capable of greatly improving denitrification efficiency by injecting an ammonia supply source and a nitric acid supply source into a process gas including nitrogen monoxide (NO) and supplying the same to a selective catalytic reactor. In particular, the selective catalytic reduction method and the selective reduction system according to the present invention reduce SO2The nitrogen removal performance is reduced and the SO with low performance is reduced2The resulting denitrification performance is reduced and the performance of the SCR process with reduced performance is improved in situ, thereby maintaining performance and improving process efficiency.
In the present invention, the "nitric acid supply source" may mean ammonium Nitrate (NH)4NO3) Or nitric acid (HNO)3)。
The selective catalytic reduction method and the selective catalytic reduction system according to the present invention are explained in detail below.
Fig. 1 is a sequence diagram illustrating a selective catalytic reduction reaction method according to the present invention.
As shown in fig. 1, the selective catalytic reduction reaction method according to the present invention includes: a step (S100) of injecting a mixture of an ammonia supply source and a nitric acid supply source into a process gas containing Nitric Oxide (NO); and a step (S200) of maintaining the temperature of the reactor into which the ammonia supply source and the nitric acid supply source are injected in the range of 200 ℃ to350 ℃.
The present inventors have found that the denitrification efficiency is further increased in the range of 200 to350 c when the nitric acid supply source is co-injected, as compared with the case where only the ammonia supply source expected to have similar characteristics is injected, which will be described in the following experimental examples.
In particular, the present invention is based on the fact that nitric acid can be decomposed at a low reaction temperature and has good compatibility with an ammonia supply sourceThe source is injected as an additive into the original ammonia-based SCR process, improving the relatively low reaction rate and SO of the original SCR reaction by virtue of the strong oxidizing power of the nitrogen oxides thus produced2And (4) durability.
In another aspect, the Selective Catalytic Reduction (SCR) method and system of the present invention can reduce Nitrogen Oxides (NO) contained in exhaust gas discharged from an enginex). The engine may be one or more of a diesel engine used as a main power source and a medium-speed diesel engine used as a power generation or auxiliary power source.
However, the Selective Catalytic Reduction (SCR) method and the SCR system according to an embodiment of the present invention are not limited to one application, and may be applied to various fields such as ships, vehicles, or factories.
First, a step S100 of injecting an ammonia supply source and a nitric acid supply source into a process gas containing Nitric Oxide (NO) will be described.
The ammonia supply source and the nitric acid supply source are sprayed in the form of droplets toward the process gas including Nitric Oxide (NO) through a nozzle of the mixed gas injection line. At this time, the mixed gas injection line may control the internal temperature at 150 to 300 ℃. Specifically, the ammonia supply source and the nitric acid supply source may be decomposed at a temperature ranging from 150 ℃ to 300 ℃ or from 200 ℃ to 300 ℃ to generate a mixed gas, and the mixed gas may be sprayed into the process gas at a temperature ranging from 150 ℃ to350 ℃, or at a temperature ranging from 200 ℃ to 300 ℃.
The molar ratio of the ammonia supply source to the nitric acid supply source may be 1:10 to 10:1, may be 1:3 to 3:1, or may be 1: 1. The denitrification efficiency can be further increased under the ammonia to nitric acid supply source (ammonium nitrate or nitric acid) molar ratio conditions as described above. However, the molar ratio of the nitric acid supply source may be determined by the concentration ratio of nitrogen dioxide/nitric oxide in the injected treatment gas, NH3/NOxConcentration ratio, SO2The concentration change and the reduction degree of denitrification efficiency.
I.e. when it is nitric oxide or SO2When the amount of the treated gas is large, the amount of the nitric acid supply source is increased as the denitrification treatment capacity and the deactivation rate are increased, in order to overcome the decrease and limitation of the denitrification efficiency of the prior SCR process required by the corresponding control, when the amount of the nitric acid supply source is nitric oxide or SO2When the amount of the treated gas is small, the denitrification efficiency can be controlled by a relatively small amount of the nitric acid supply source, and when an excessive amount is used, the denitrification efficiency is rather lowered.
Further, a catalyst may be included in the reactor containing the process gas, which catalyst may include an ammonia SCR denitrification catalyst. Specifically, it is possible to load the active ingredient on titanium dioxide (TiO)2) Supported catalysts or copper-containing zeolitic catalysts, e.g. V-Sb/TiO as conventional catalysts may be included in the reactor2. But is not limited thereto.
Wherein, the ammonia supply source can be urea water, ammonia water or gaseous ammonia. In addition, the nitric acid supply source may be ammonium Nitrate (NH)4NO3) Or nitric acid (HNO)3)。
As a specific embodiment, the method may further include the step of independently injecting a nitric acid supply source into the process gas containing Nitric Oxide (NO). This may be to improve process performance, achieve in situ catalyst regeneration and improve durability independently of the original process. In more detail, the additive injection line through which the process gas is injected when the nitric acid supply source is independently injected may be formed separately from the mixed gas injection line that mixedly injects the ammonia supply source and the nitric acid supply source as described above.
As another aspect, a branch pipe connecting the additive injection line and the mixed gas injection line may be included, and the separate nitric acid supply source may inject the mixed gas mixed by the ammonia supply source and the nitric acid supply source through the branch pipe.
Then, the selective catalytic reduction reaction method according to the present invention includes the step of maintaining the in-reactor temperature of the mixed gas injected in the range of 200 ℃ to350 ℃ (S200).
According to the selective catalytic reduction method and the selective catalytic reduction system of the present invention, the ammonia supply source and the nitric acid supply source are simultaneously injected into the process gas containing nitrogen monoxide (NO), and the denitrification effect can be sufficiently exhibited even in the temperature range of 200 ℃ to350 ℃ on average. More specifically, the temperature in the reactor into which the mixed gas is injected may be maintained in the range of 250 ℃ to350 ℃.
On the other hand, when the temperature in the reactor into which the mixed gas is injected is less than 200 ℃, the reaction temperature is too low to sufficiently exhibit denitrification efficiency. In addition, in the case of more than 350 ℃, although the conversion rate of nitric oxide is high, it is not recommended in consideration of energy inefficiency and side reactions due to excessive use of energy, compared to the difference in denitrification efficiency in the range of 200 ℃ to350 ℃. Therefore, it is preferable to maintain the temperature in the reactor in the range of 200 ℃ to350 ℃.
That is, according to the present invention, by injecting the ammonia reducing agent and the nitric acid supply source into the process gas containing nitric oxide, the denitrification efficiency can be sufficiently obtained even if the temperature in the reactor is in the range of 200 ℃ to 300 ℃.
Further, the selective catalytic reduction reaction method according to the present invention is characterized by using a nitric acid supply source (ammonium Nitrate (NH) injected into the exhaust gas4NO3) Or nitric acid (HNO)3) To improve the resistance of the catalyst to sulfur poisoning.
More specifically, in the selective catalytic reduction reaction method, SO2Conversion to SO by oxidation3Said SO3By means of reaction with NH3And H2Reaction of O to form ammonium sulfate (NH)4HSO4) (AS) or ammonium hydrogen sulfate ((NH)4)2SO4) (ABS). However, the generation of the AS or ABS, which causes a decrease in catalyst performance or reactor aging, may decrease the NO conversion rate in the reactor.
Thus, ammonium Nitrate (NH) added to the reactor4NO3) Or nitric acid (HNO)3) While performing a selective catalytic reduction reaction, converting AS (NH) produced in the reaction into4HSO4) Or ABS is simultaneously decomposed in situ, thereby increasing resistance to said sulfur poisoning.
In the present invention, as the resistance to sulfur poisoning is improved, the nitrogen oxide removal efficiency does not decrease even when the engine is operated for a long time.
Fig. 2 and 3 are schematic diagrams of the selective catalytic reduction reaction system of the present invention.
Referring to fig. 2, the present invention relates to a selective catalytic reduction reaction system 10, characterized by comprising: an exhaust gas reactor 100, the exhaust gas reactor 100 including an exhaust gas containing Nitric Oxide (NO) and including a catalyst for a selective catalytic reduction reaction therein; a mixed gas injection line 300, the mixed gas injection line 300 for injecting an ammonia supply and a nitric acid supply into the exhaust gas reactor; and a first control part 310, the first control part 310 being used for controlling the injection amount of the ammonia supply source and the nitric acid supply source; wherein the temperature in the off-gas reactor into which the ammonia supply source and the nitric acid supply source are injected is maintained in the range of 200 ℃ to350 ℃.
The exhaust gas reactor 100 may mean a fluid line for flowing an exhaust gas containing Nitric Oxide (NO), and may mean a fluid line for flowing an exhaust gas discharged from an exhaust gas generating source. The exhaust gas generating source may be a combustion furnace, a process heating furnace, or an internal combustion engine, and may be a device for discharging harmful gases such as nitrogen oxides by combustion, synthesis, decomposition, or the like of a substance.
Further, the exhaust gas reactor 100 may include a temperature control device (not shown) for controlling the temperature inside the reactor 100. Specifically, the temperature inside the reactor may be controlled to a temperature range of 200 ℃ to350 ℃ using the temperature control device.
According to the selective catalytic reduction reaction system 10 of the present invention, the ammonia supply source and the nitric acid supply source are simultaneously injected into the process gas containing Nitric Oxide (NO), and the denitrification effect can be sufficiently exerted even in the temperature range of 200 ℃ to350 ℃ on average. More specifically, the temperature inside the off-gas reactor 100 may be maintained in the range of 250 ℃ to350 ℃.
The ammonia supply source and the nitric acid supply source may be stored together during the selective catalytic reduction reaction, and may be stored in the reducing agent storage container 200.
The mixed gas generated by decomposing the ammonia supply source and the nitric acid supply source may be transferred to the mixed gas injection line 300, and may be driven by the mixed gas to be transferred to the exhaust gas reactor 100. At this time, the injection amount of the mixed gas may be controlled by the first control part 310 provided in the mixed gas injection line 300.
Also, the mixed gas injection line has a temperature ranging from 150 ℃ to 300 ℃, and the ammonia supply source and the nitric acid supply source can be decomposed to generate a uniform mixed gas in the mixed gas injection line.
On the other hand, as described above, the ammonia supply source may mean urea water, ammonia water, or gaseous ammonia, and the nitric acid supply source may mean ammonium Nitrate (NH)4NO3) Or nitric acid (HNO)3)。
In a specific embodiment, in order to improve the performance of the SCR process and the degradation of the catalyst and process performance, the additive storage container 200', the additive injection line 300', and the second controller 310' may be provided independently of the existing reducing agent supply system to use the nitric acid supply source, in order to inject the additive only when necessary.
Referring to fig. 3, an additive storage container 200' may be included, and an additive injection line 300' for independently injecting a nitric acid supply source stored in the additive storage container 200' into the exhaust gas reactor 100 may be further included. Also, the additive injection line 300 'may include a second control part 310' for controlling the injection amount of the nitric acid supply source.
This is to inject the nitric acid supply into the exhaust gas reactor 100 only when needed, in which case process performance, catalyst regeneration in situ, durability, etc. can be improved independently of the original process.
Further, the additive injection line 300' may further include a branch pipe 311 that transmits a nitric acid supply source to the mixed gas injection line 300. Through the branch pipe 311, an independent nitric acid supply source can inject the mixed gas mixed by the ammonia supply source and the nitric acid supply source.
Detailed Description
The present invention will be described in more detail below with reference to examples and experimental examples.
However, the following examples and experimental examples are merely illustrative of the present invention, and the contents of the present invention are not limited to the following examples and experimental examples.
< example >
Examples 1 to 9 and comparative examples 1 to 6
In order to use V-Sb/TiO as a commonly used denitrification catalyst2The denitrification experiment was performed with the catalyst as a subject, and after filling the catalyst in the center of the reactor, a gas having the gas composition shown in table 1 below was introduced into the reactor.
For reference, example 8 and comparative example 5 were used by preparing an aqueous solution having an ammonia concentration of 300ppm using ammonia water without injecting ammonia. In particular, in example 8, aqueous solutions were prepared by mixing aqueous ammonia and ammonium nitrate so as to reach 300ppm each, and the solutions were simultaneously injected. Further, example 9 and comparative example 6 were used by preparing an aqueous solution using urea water without injecting ammonia so that the concentration of injected urea reached 150 ppm. In example 9, urea water and ammonium nitrate were mixed so as to be 150ppm and 300ppm, respectively, to prepare aqueous solutions, and the aqueous solutions were injected simultaneously.
The reaction conditions and gas components of the specific examples and comparative examples are shown in table 1 below.
[ TABLE 1 ]
< examples of experiments >
Experimental example 1 measurement of Activity improvement Effect after injection of additives
The denitrification reaction experiment was performed using the reaction conditions and gas components of the examples and comparative examples.
First, 0.5g of a catalyst having a particle size of 0.8mm to 1.0mm on average was placed at the very center of the reactor at 2000cc per minute of 5% O2/N2The pretreatment was carried out for 2 hours at 200 ℃.
Also, reactants having the compositions of table 1 were charged. Liquid water was injected through an ultrasonic nozzle at a rate of 0.08ml per minute using a liquid chromatography pump (HPLC pump) to achieve 5 vol% H2And (4) O component.
The reaction temperature was increased from 200 ℃ to 500 ℃ at a rate of 10 ℃/min at intervals of 50 ℃ and observed. The reaction product was cooled to remove solid components such as water and salt, and NO were measured by a Testo350K analyzer2、SO2And the like, and the catalytic denitrification reaction performance is analyzed.
The results are shown in Table 2 below.
[ TABLE 2 ]
As can be seen from table 2, the nitric oxide conversion ratios of the examples were improved as compared with the comparative examples. Particularly, the excellent nitric oxide conversion rate was confirmed even in the temperature range of 200 ℃ to350 ℃.
Also, when ammonium nitrate was injected, the denitrification efficiency was found to be further increased in the range of 200 to350 ℃ compared to the injection of nitric acid alone.
Experimental example 2 inactivation-improving effect after injection of additive
V-Sb/TiO as a conventional denitrification catalyst was treated under the conditions of example 3, example 5, example 8 and comparative example 12Catalyst is taken as object, SO is performed2And (4) inactivation experiment. For reference, 500ppm SO was injected into the reactor2。
The reaction conditions and gas components of the specific examples and comparative examples are shown in table 3 below.
[ TABLE 3 ]
Experiments and analysis were performed in the same manner as in experimental example 1, except that the reaction temperature was fixed to 250 deg.c, and after the reaction temperature was maintained at 250 deg.c, the reactants were injected, and the deactivation reaction was performed for 14 hours.
The results are shown in fig. 4.
FIG. 4 is SO illustrating a selective catalytic reduction reaction method according to an embodiment of the present invention2Graph of the results of the inactivation experiment.
Referring to fig. 4, it is understood that in the case where ammonium nitrate was independently added to the ammonia reducing agent at a level of 300ppm and in the case where ammonium nitrate was mixed with aqueous ammonia and simultaneously injected for use, the initial NO concentration was maintained even after 14 hours, but in the case where ammonium nitrate was not added (black), the NO concentration increased after 14 hours. This means that the ammonium nitrate added according to the invention increases the sulphur resistance of the catalyst. Therefore, the injection of ammonium nitrate according to the present invention may be used as a method of improving the resistance of a selective catalytic reduction catalyst to sulfur poisoning.
EXAMPLE 3 in situ regeneration experiment of catalyst Activity
V-Sb/TiO as a conventional denitrification catalyst according to the conditions of example 52Catalyst is taken as object, SO is performed2And (4) inactivation experiment. In this case, reaction experimental conditions for confirming the deactivation inhibition performance by additional injection of ammonium nitrate were as follows.
[ TABLE 4 ]
First, 0.5g of a catalyst having a particle size of 0.8mm to 1.0mm was placed at the very center of the reactor at 5% O of 2000cc per minute2/N2The pretreatment was carried out for 2 hours at 200 ℃.Subsequently, the temperature of the reactor was increased to 250 ℃ as the reaction temperature, and then the reaction was carried out. Then, H is simultaneously implanted2O and SO2The reaction was carried out.
In the generation of SO2After 25 hours of deactivation, in order to observe the deactivation inhibitory effect of ammonium nitrate, ammonium nitrate was injected at a rate of 0.08 ml/min during 3 hours using a liquid chromatography pump (HPLC pump). At this time, the reinforcing agent was injected so that the mol% concentration in the total flow rate reached 100ppm, and an ultrasonic nozzle was used to smoothly inject the reinforcing agent into the reactor and decompose the reinforcing agent without precipitating as a solid.
The results are shown in fig. 5.
Fig. 5 is a graph illustrating deactivation inhibiting performance after additional injection of ammonium nitrate in the selective catalytic reduction reaction method according to an embodiment of the present invention.
Referring to FIG. 5, NH is injected4NO3When the concentration of NO was reduced to about 130ppm, it was confirmed. Furthermore, it is known that in-situ injection of ammonium nitrate in a deactivated catalytic reaction can improve the catalyst activity (NO reduction rate) to a performance similar to that before deactivation.
EXAMPLE 4 variation of ammonium nitrate concentration resulting in NO and SO
2
Concentration change experiment of
V-Sb/TiO as a conventional denitrification catalyst according to the conditions of example 1 and example 32Catalyst is taken as object, SO is performed2And (4) inactivation experiment. For reference, 500ppm SO was injected into the reactor2。
Specific example reaction conditions and gas components are shown in table 5 below.
[ TABLE 5 ]
Experiments and analysis were performed in the same manner as in experimental example 1, except that the reaction temperature was fixed at 200 ℃, and after the reactants were injected after the reaction temperature was maintained at 200 ℃, the deactivation reaction was performed for 14 hours.
The results are shown in fig. 6 and 7.
FIGS. 6 and 7 are SO illustrating a selective catalytic reduction reaction method according to an embodiment of the present invention2Graph of the results of the inactivation experiment (FIG. 6: example 1, FIG. 7: example 3). Specifically, fig. 6 and 7 illustrate an SO2Time-varying NO and SO in constant temperature continuous injection experiments2Graph of concentration change.
Referring to fig. 6, when ammonium nitrate was added to the ammonia reducing agent at a level of 35ppm, the NO concentration was changed from 120ppm to 170ppm after the lapse of 14 hours, and deactivation occurred.
Referring to fig. 7, when ammonium nitrate was added to the ammonia reducing agent at a level of 100ppm, the NO concentration was changed from 90ppm to 120ppm after the lapse of 14 hours, and deactivation occurred. It is thus understood that the deactivation is improved by increasing the ammonium nitrate concentration. From this, it is found that the inactivation was suppressed by 20ppm in the same time as compared with the original 17% inactivation data.
On the other hand, referring to FIGS. 6 and 7, SO is shown2Decreases with time. This shows that in the examples of the present invention, SO was produced simultaneously with the selective catalytic reduction reaction due to the addition of ammonia2Conversion to NH4HSO4(AS) and (NH)4)2SO4(ABS), whereby the SO2Will be reduced.
On the other hand, the AS or ABS reduces the conversion rate of NO in the reactor, which in the example may improve the resistance to sulfur poisoning by decomposing the AS or ABS by the added ammonium nitrate (or nitric acid).
Industrial applicability
The selective catalytic reduction method and the selective catalytic reduction system according to the present invention can be used to improve the denitrification efficiency and prevent SO2The denitrification performance is reduced, and the nitrogen oxide is effectively removed.
Claims (13)
1. A selective catalytic reduction reaction method comprising:
a step of mixing and injecting an ammonia supply source and a nitric acid supply source into a process gas containing Nitric Oxide (NO); and
a step of maintaining the temperature of the reactor into which the ammonia supply source and the nitric acid supply source are injected in the range of 200 ℃ to350 ℃.
2. The scr reaction method of claim 1, further comprising:
a step of independently injecting a nitric acid supply source into the process gas containing nitric oxide.
3. The selective catalytic reduction reaction method according to claim 1,
an ammonia supply source and a nitric acid supply source are sprayed in the form of droplets through a nozzle toward a process gas containing Nitric Oxide (NO),
the spraying of the ammonia supply and the nitric acid supply is at a temperature of 150 ℃ to 300 ℃.
4. The selective catalytic reduction reaction method according to claim 1,
the ammonia supply source is urea water, ammonia water or gaseous ammonia,
the nitric acid supply source is ammonium Nitrate (NH)4NO3) Or nitric acid (HNO)3)。
5. The selective catalytic reduction reaction method according to claim 1,
the molar ratio of the ammonia supply source to the nitric acid supply source is 1:10 to 10: 1.
6. The selective catalytic reduction reaction method according to claim 1,
the injection amount of the nitric acid supply source is determined according to the concentration ratio of nitrogen dioxide to nitric oxide in the treatment gas and NH3/NOxConcentration ratio, SO2The concentration and the degree of decrease in the denitrification efficiency.
7. The selective catalytic reduction reaction method according to claim 1,
the resistance of the catalyst to sulfur poisoning is enhanced by the nitric acid supply injected into the reactor.
8. The selective catalytic reduction reaction method according to claim 1,
the nitric acid supply source is ammonium sulfate ((NH4) generated together with the selective catalytic reduction reaction)2SO4ABS: ammonium bisulfate) or Ammonium bisulfate (NH)4HSO4And AS: ammonium sulfate) is subjected to in situ decomposition while performing a selective catalytic reduction reaction, thereby improving resistance to the sulfur poisoning.
9. A selective catalytic reduction reaction system, comprising:
an exhaust gas reactor including an exhaust gas containing Nitric Oxide (NO) equipped therein with a catalyst for a selective catalytic reduction reaction;
a mixed gas injection line for injecting an ammonia supply and a nitric acid supply into the exhaust gas reactor; and
a first control portion for controlling injection amounts of the ammonia supply source and the nitric acid supply source;
wherein the temperature in the off-gas reactor injected by the ammonia supply source and the nitric acid supply source is maintained in the range of 200 ℃ to350 ℃.
10. The SCR reaction system of claim 9,
the mixed gas injection line has a temperature in a range of 150 ℃ to 300 ℃, and the ammonia supply source and the nitric acid supply source are decomposed to generate a mixed gas in the mixed gas injection line.
11. The SCR reaction system of claim 9,
the ammonia supply source is urea water, ammonia water or gaseous ammonia, and the nitric acid supply source is ammonium Nitrate (NH)4NO3) Or nitric acid (HNO)3)。
12. The scr reaction system of claim 9, further comprising:
an additive injection line for independently injecting a nitric acid supply source into the off-gas reactor;
the additive injection line includes a second control portion for controlling an injection amount of the nitric acid supply source.
13. The SCR reaction system of claim 12,
the additive injection line is connected to a branch pipe that transmits a nitric acid supply source to the mixed gas injection line.
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| JPH09290136A (en) * | 1996-04-30 | 1997-11-11 | Babcock Hitachi Kk | Method for cleaning of exhaust gas and apparatus therefor |
| CN101623591A (en) * | 2009-08-10 | 2010-01-13 | 杭州蓝海环保工程有限公司 | Desulfurization and denitrification oxidation process of single-stage catalytic reduction absorption method |
| CN106705091A (en) * | 2016-12-21 | 2017-05-24 | 西安交通大学 | System and method for slowing down deactivation of SCR catalyst and blocking of air preheater |
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| KR100356367B1 (en) * | 1999-09-07 | 2002-10-19 | 코오롱건설주식회사 | Acid-gas resistance catalyst for removing nitrogen oxide |
| JP4864231B2 (en) * | 2001-06-06 | 2012-02-01 | バブコック日立株式会社 | Denitration catalyst structure and exhaust gas denitration method using the same |
| KR101400608B1 (en) | 2012-03-12 | 2014-05-27 | 박광희 | Catalyst for selective oxidation of ammonia, manufacturing method same and process for selective oxidation of ammonia using same |
| KR102178597B1 (en) * | 2015-12-21 | 2020-11-13 | 현대중공업 주식회사 | Apparatus and Method for Catalyst Mnagement in Vessel Denitrifing System |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH09290136A (en) * | 1996-04-30 | 1997-11-11 | Babcock Hitachi Kk | Method for cleaning of exhaust gas and apparatus therefor |
| CN101623591A (en) * | 2009-08-10 | 2010-01-13 | 杭州蓝海环保工程有限公司 | Desulfurization and denitrification oxidation process of single-stage catalytic reduction absorption method |
| CN106705091A (en) * | 2016-12-21 | 2017-05-24 | 西安交通大学 | System and method for slowing down deactivation of SCR catalyst and blocking of air preheater |
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