CN211636011U - Large-circulation self-adaptive SCR denitration system - Google Patents
Large-circulation self-adaptive SCR denitration system Download PDFInfo
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- CN211636011U CN211636011U CN201922254011.3U CN201922254011U CN211636011U CN 211636011 U CN211636011 U CN 211636011U CN 201922254011 U CN201922254011 U CN 201922254011U CN 211636011 U CN211636011 U CN 211636011U
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Abstract
The utility model provides a major cycle self-adaptation SCR deNOx systems, include gas-gas heat exchanger, nozzle, spout ammonia mechanism and the SCR reactor that communicates in proper order through flue gas pipeline, first branch pipeline and second branch pipeline are connected to the gas outlet of SCR reactor, and first branch pipeline communicates with the hot side entry of gas-gas heat exchanger, and second branch pipeline passes through circulating fan and links to each other the flue gas pipeline between gas-gas heat exchanger and the nozzle. The utility model discloses a high temperature flue gas after making SCR denitration reaction through circulating fan carries out secondary direct heating to former flue gas, so that it satisfies flue gas denitration's temperature demand, realize denitration reaction temperature's self-adaptation regulation, and with the high temperature tail gas after the denitration reaction and the direct mixing of former flue gas, both can make big flue gas volume all take charge of denitration reaction heat, reduce the reaction temperature rise, avoid catalyst high temperature deactivation, can dilute former flue gas again, reduce the flue gas NOx concentration that gets into the SCR reactor, be favorable to the final discharge to reach standard of denitration reaction tail gas.
Description
Technical Field
The utility model belongs to the technical field of the denitration technique that contains the NOx flue gas, concretely relates to major cycle self-adaptation SCR deNOx systems.
Background
The stainless steel mixed acid waste liquid contains HNO with higher concentration3Generally, the concentration of the waste acid is 100-180g/L, the waste acid with high concentration is usually neutralized by a waste water neutralizing station, a large amount of sludge is formed, the disposal cost is high, and the waste of nitric acid is serious.
At present, stainless steel production enterprises gradually turn to the most advanced technology of mixed acid regeneration by spray roasting to treat HF and HNO in mixed acid3Recovery was carried out, but HNO3Decomposed into NOx in a high-temperature environment, and generally about 30% of HNO is still present after recovery3Enters the system flue gas in the form of NOx and needs to be denitrated by an SCR method,the concentration of NOx in the flue gas is up to 20000-36000mg/Nm3。
On the one hand, in order to make the flue gas discharge to reach standard, must carry out the denitration to it and handle, and sour regeneration system flue gas temperature often controls about 25 ℃ before getting into SCR denitrification facility to do benefit to NOx's wet process denitration and retrieve HNO3. The activity temperature of most vanadium-titanium-based catalysts in the SCR denitration reaction is generally 280-330 ℃, in order to enable the denitration reaction to be normally carried out, the system flue gas must be heated, and the waste of fuel energy is caused by adopting a burner heating mode.
On the other hand, the SCR denitration reaction is an exothermic reaction:
the higher the concentration of NOx is, the larger the heat release quantity is, and under the condition of high-concentration NOx flue gas, the over-temperature burning of the catalyst is easily caused; or adopt high temperature resistant denitration catalyst, cause the promotion of production running cost.
SUMMERY OF THE UTILITY MODEL
The utility model aims at overcoming current SCR denitrification facility and adopting the nozzle heating, fuel energy resource consumption is big, and the denitration reaction is exothermic and easily causes the problem of catalyst high temperature inactivation.
Therefore, the utility model provides a big circulation self-adaptation SCR deNOx systems, include gas-gas heat exchanger, nozzle, ammonia spraying mechanism and the SCR reactor that communicates in proper order through flue gas pipeline, first branch pipeline and second branch pipeline are connected to the gas outlet of SCR reactor, first branch pipeline with the hot side entry intercommunication of gas-gas heat exchanger, the hot side exit linkage chimney of gas-gas heat exchanger, the second branch pipeline passes through circulating fan intercommunication flue gas pipeline between gas-gas heat exchanger and the nozzle.
Furthermore, a third branch pipeline is connected to the outlet side of the circulating fan on the second branch pipeline, and the third branch pipeline is communicated with a flue gas pipeline in front of the cold side inlet of the gas-gas heat exchanger.
Furthermore, an air mixing mechanism is arranged on a flue gas pipeline between the burner and the SCR reactor.
Furthermore, thermometers are arranged on the flue gas pipeline in front of the cold side inlet of the gas-gas heat exchanger, the flue gas pipeline between the cold side outlet of the gas-gas heat exchanger and the second branch pipeline, the flue gas pipeline between the second branch pipeline and the burner, the flue gas pipeline between the ammonia spraying mechanism and the SCR reactor, and the flue gas pipelines at the hot side outlets of the SCR reactor, the first branch pipeline and the gas-gas heat exchanger.
Further, pressure gauges are arranged on the flue gas pipeline in front of the cold side inlet of the gas-gas heat exchanger, the flue gas pipeline between the cold side outlet of the gas-gas heat exchanger and the second branch pipeline, the flue gas pipeline between the ammonia spraying mechanism and the SCR reactor, and the flue gas pipelines at the hot side outlet of the first branch pipeline, the second branch pipeline and the gas-gas heat exchanger.
Furthermore, flow meters are arranged on a flue gas pipeline in front of a cold side inlet of the gas-gas heat exchanger and a flue gas pipeline between the ammonia spraying mechanism and the SCR reactor.
Furthermore, an air supply pipeline is connected to the flue gas pipeline in front of the cold side inlet of the gas-gas heat exchanger.
Compared with the prior art, the beneficial effects of the utility model are that:
(1) the utility model provides a high temperature tail gas after this kind of major cycle self-adaptation SCR deNOx systems makes SCR reactor internal reaction through circulating fan carries out secondary direct heating to former flue gas, so that it satisfies flue gas denitration's temperature demand, realize denitration reaction temperature's self-adaptation regulation, improved and simply used outside gas energy heating to the required active temperature's of flue gas denitration SCR reaction catalyst extra energy resource consumption, realized temperature self-adaptation and need not to continuously ignite, saved the gas energy consumption.
(2) The utility model provides a high temperature tail gas after the denitration reaction directly mixes with former flue gas in this kind of major cycle self-adaptation SCR deNOx systems, both can make big flue gas volume all bear the weight of the denitration reaction heat, reduce the reaction temperature rise, avoid catalyst high temperature inactivation, can dilute the system inside of former flue gas again, reduced the flue gas NOx concentration that finally gets into the SCR reactor, NOx distributed state in the flue gas has been improved simultaneously, be favorable to the final discharge to reach standard of denitration reaction tail gas.
The present invention will be described in further detail with reference to the accompanying drawings.
Drawings
FIG. 1 is the structural schematic diagram of the large-cycle self-adaptive SCR denitration system.
Description of reference numerals: 1. a gas-gas heat exchanger; 2. a chimney; 3. burning a nozzle; 4. a second branch line; 5. a circulating fan; 6. a wind mixing mechanism; 7. an ammonia spraying mechanism; 8. an air supply duct; 9. an SCR reactor; 10. a third branch line; 11. a first branch line; 12. a pressure gauge; 13. a flow meter; 14. a thermometer.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.
In the description of the present invention, it is to be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like indicate orientations or positional relationships based on those shown in the drawings, and are merely for convenience of description and simplicity of description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore, are not to be construed as limiting the present invention.
The terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature; in the description of the present invention, "a plurality" means two or more unless otherwise specified.
As shown in fig. 1, this embodiment provides a large-circulation self-adaptive SCR denitration system, which includes a gas-gas heat exchanger 1, a burner 3, an ammonia spraying mechanism 7, and an SCR reactor 9 that are sequentially communicated through a flue gas pipeline, where an air outlet of the SCR reactor 9 is connected to a first branch pipeline 11 and a second branch pipeline 4, the first branch pipeline 11 is communicated with a hot side inlet of the gas-gas heat exchanger 1, a hot side outlet of the gas-gas heat exchanger 1 is connected to a chimney 2, and the second branch pipeline 4 is communicated with the flue gas pipeline between the gas-gas heat exchanger 1 and the burner 3 through a circulating fan 5.
In the embodiment, a cold side inlet of a gas-gas heat exchanger 1 is externally connected with a NOx-containing flue gas generation device through a flue gas pipeline, NOx-containing flue gas enters the gas-gas heat exchanger 1 from the cold side inlet of the gas-gas heat exchanger 1 for indirect heat exchange, then is discharged from a cold side outlet of the gas-gas heat exchanger 1, and then is directly heated at a burner 3 by supplying gas and combustion-supporting air for combustion, so that the temperature of the flue gas is raised to the required active temperature of a catalyst in an SCR reactor 9, which is generally 280 ℃, and meanwhile, the sum of the temperature and the temperature raised by the flue gas after denitration reaction is not more than the upper limit of the tolerance temperature of the catalyst, which is generally 450 ℃; then the mixed flue gas is fully mixed with sprayed ammonia (or ammonia water, urea and the like) at the position of the ammonia spraying mechanism 7, and the mixed flue gas enters an SCR reactor 9 for denitration reaction to remove NOx and meet the emission standard; the temperature of the flue gas after the denitration reaction is raised due to the heat release of the denitration reaction, the heated flue gas enters the hot side inlet of the gas-gas heat exchanger 1 through the first branch pipeline 11, the raw flue gas is preheated in the gas-gas heat exchanger 1 and then is discharged from the hot side outlet of the gas-gas heat exchanger 1, and is discharged to the atmosphere through the chimney 2, on the other hand, the heated flue gas directly reflows to the flue gas pipeline of the cold side outlet of the raw flue gas after passing through the gas-gas heat exchanger 1 through the circulating fan 5 before entering the hot side inlet of the gas-gas heat exchanger 1 to directly heat the raw flue gas, and the concentration of NOx in the raw flue gas generated by the external NOx-containing flue gas generating device is constantly changed, at the moment, the air volume entering the second branch pipeline 4 to directly heat the raw flue gas can be adaptively adjusted through the circulating fan 5, so that the temperature of the flue gas entering the SCR reactor 9 can stably reach the activity temperature required by the catalyst in the SCR reactor 9 Therefore, the heat supply of the burner 3 can be gradually reduced until the heat supply is stopped, the SCR denitration system completely achieves self-adaptive reaction temperature control, the burner 3 is not required to continuously ignite under the condition of enough NOx concentration, and the burner 3 is only used as a system initial starting temperature supply source. According to the SCR denitration system, the air volume is adjusted through the circulating fan 5, so that high-temperature tail gas after reaction in the SCR reactor 9 can carry out secondary direct heating on raw flue gas, the temperature requirement of flue gas denitration can be met, the self-adaptive adjustment of denitration reaction temperature can be realized, the extra energy consumption that external fuel gas energy is simply used for heating to the active temperature required by a flue gas denitration SCR reaction catalyst in the prior art can be improved, the temperature self-adaption can be realized without continuous ignition, and the fuel gas energy consumption can be saved; simultaneously, high-temperature tail gas after denitration reaction is directly mixed with raw flue gas, so that large flue gas volume can be used for carrying denitration reaction heat, reaction temperature rise is reduced, high-temperature inactivation of a catalyst is avoided, the inside of a system of the raw flue gas can be diluted, the concentration of flue gas NOx finally entering the SCR reactor is reduced, the distribution state of the NOx in the flue gas is improved, and the final standard emission of the denitration reaction tail gas is facilitated.
In a detailed implementation manner, the circulating fan 5 may be a variable-frequency circulating fan for adjusting the circulating air volume, or the variable-frequency circulating fan may be replaced by a fixed-frequency fan equipped with an adjusting valve. The ammonia spraying mechanism 7 is a device for spraying gas into the flue gas pipeline, and the specific structure thereof is the prior art and is not described herein again. In the process of mixing ammonia (or ammonia water, urea and the like) sprayed by the ammonia spraying mechanism 7 with the flue gas, an air mixing mechanism 6 can be arranged on the flue gas pipeline between the burner 3 and the SCR reactor 9, and the air mixing effect in the flue gas pipeline is enhanced by the air mixing mechanism 6, so that the sprayed ammonia and the flue gas are fully mixed; the specific structure of the air mixing mechanism 6 is the prior art, such as a mixing fan, and the structure thereof is not described herein again.
Preferably, the outlet side of the circulating fan 5 on the second branch pipeline 4 is connected with a third branch pipeline 10, the third branch pipeline 10 is communicated with the flue gas pipeline in front of the cold side inlet of the gas-gas heat exchanger 1, part of high-temperature flue gas on the second branch pipeline 4 is supplied to the flue gas pipeline in front of the cold side inlet of the gas-gas heat exchanger 1 through the third branch pipeline 10, and the raw flue gas in the flue gas pipeline in front of the cold side inlet of the gas-gas heat exchanger 1 can be preheated to prevent acid gas in the raw flue gas from condensing and corroding the gas-gas heat exchanger, and meanwhile, the denitration reaction heat can be further shared.
In order to better control the denitration system and ensure the normal operation of the denitration system, a plurality of thermometers 14 are arranged on the denitration system along the flue gas advancing direction to carry out interlocking control and actual temperature check on the temperature of the system, and specifically, a thermometer T-1 is arranged on a flue gas pipeline in front of a cold side inlet of the gas-gas heat exchanger 1, a thermometer T-2 is arranged on a flue gas pipeline between a cold side outlet of the gas-gas heat exchanger 1 and a second branch pipeline 4, a thermometer T-3 is arranged on a flue gas pipeline between the second branch pipeline 4 and a burner 3, a thermometer T-4 is arranged on a flue gas pipeline between an ammonia spraying mechanism 7 and an SCR reactor 9, a thermometer T-5 is arranged on the SCR reactor 9, a thermometer T-6 is arranged on a first branch pipeline 11, and a thermometer T-7 is arranged on a flue gas pipeline at a hot side outlet of the gas-gas heat exchanger 1; the system comprises a gas-gas heat exchanger 1, a circulating fan 5, a burner 3, a burner 4, a T-1, a T-2, a T-6 and a T-7, wherein the T-1, the T-2, the T-6 and the T-7 are used for monitoring the efficiency of the gas-gas heat exchanger 1, the T-2, the T-3 and the T-6 are used for interlocking regulation and control of the air quantity of the circulating fan 5, the T-3 and the T-4 are used for regulating the heat demand supply of the burner 3 to meet the temperature required by the flue gas denitration SCR reaction.
The denitration system is provided with a plurality of pressure gauges 12 in the flue gas advancing direction for monitoring and interlocking control of the pressure condition in the system, specifically, a pressure gauge P-1 is arranged on a flue gas pipeline in front of a cold side inlet of a gas-gas heat exchanger 1, a pressure gauge P-2 is arranged on a flue gas pipeline between a cold side outlet of the gas-gas heat exchanger 1 and a second branch pipeline 4, a pressure gauge P-3 is arranged on a flue gas pipeline between an ammonia spraying mechanism 7 and an SCR reactor 9, a pressure gauge P-4 is arranged on a first branch pipeline 11, a pressure gauge P-5 is arranged on a flue gas pipeline at a hot side outlet of the gas-gas heat exchanger 1, and a pressure gauge P-6 is arranged on the second branch pipeline 4; wherein, P-1, P-2, P-3, P-4 and P-5 are gradually reduced, the smoke of the monitoring system normally advances, and P-6 is used for monitoring and interlocking control of the circulating wind pressure of the circulating fan 5.
In addition, in the case that the heat release of the denitration reaction in the SCR reactor of the denitration system completely exceeds the adjustment range of the circulating fan 5, an air supply duct 8 may be connected to the flue gas duct in front of the cold side inlet of the gas-gas heat exchanger 1, and the accident condition reduction and the catalyst equipment protection may be performed by supplying air to the NOx-containing flue gas through the air supply duct 8 in an emergency.
The above illustration is merely an illustration of the present invention, and does not limit the scope of the present invention, and all designs identical or similar to the present invention are within the scope of the present invention.
Claims (7)
1. The utility model provides a large circle self-adaptation SCR deNOx systems which characterized in that: the ammonia spraying device comprises a gas-gas heat exchanger, a burner, an ammonia spraying mechanism and an SCR (selective catalytic reduction) reactor which are sequentially communicated through a flue gas pipeline, wherein a gas outlet of the SCR reactor is connected with a first branch pipeline and a second branch pipeline, the first branch pipeline is communicated with a hot side inlet of the gas-gas heat exchanger, a hot side outlet of the gas-gas heat exchanger is connected with a chimney, and the second branch pipeline is communicated with the flue gas pipeline between the gas-gas heat exchanger and the burner through a circulating fan.
2. The large-cycle adaptive SCR denitration system of claim 1, wherein: and the outlet side of the circulating fan on the second branch pipeline is connected with a third branch pipeline, and the third branch pipeline is communicated with a flue gas pipeline in front of the cold side inlet of the gas-gas heat exchanger.
3. The large-cycle adaptive SCR denitration system of claim 1, wherein: and an air mixing mechanism is arranged on a flue gas pipeline between the burner and the SCR reactor.
4. The large-cycle adaptive SCR denitration system of claim 1, wherein: thermometers are arranged on the flue gas pipeline in front of the cold side inlet of the gas-gas heat exchanger, the flue gas pipeline between the cold side outlet of the gas-gas heat exchanger and the second branch pipeline, the flue gas pipeline between the second branch pipeline and the burner, the flue gas pipeline between the ammonia spraying mechanism and the SCR reactor, and the flue gas pipelines at the hot side outlet of the SCR reactor, the first branch pipeline and the gas-gas heat exchanger.
5. The large-cycle adaptive SCR denitration system of claim 1, wherein: and pressure gauges are arranged on the flue gas pipeline in front of the cold side inlet of the gas-gas heat exchanger, the flue gas pipeline between the cold side outlet of the gas-gas heat exchanger and the second branch pipeline, the flue gas pipeline between the ammonia spraying mechanism and the SCR reactor, and the flue gas pipelines at the hot side outlet of the first branch pipeline, the second branch pipeline and the gas-gas heat exchanger.
6. The large-cycle adaptive SCR denitration system of claim 1, wherein: flow meters are arranged on the flue gas pipeline in front of the cold side inlet of the gas-gas heat exchanger and the flue gas pipeline between the ammonia spraying mechanism and the SCR reactor.
7. The large-cycle adaptive SCR denitration system of claim 1, wherein: an air supply pipeline is connected to the flue gas pipeline in front of the cold side inlet of the gas-gas heat exchanger.
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| CN110841476A (en) * | 2019-12-16 | 2020-02-28 | 中冶南方工程技术有限公司 | Large-cycle self-adaptive SCR denitration system and method |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN110841476A (en) * | 2019-12-16 | 2020-02-28 | 中冶南方工程技术有限公司 | Large-cycle self-adaptive SCR denitration system and method |
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