CN215539740U - Tertiary flue gas low temperature is desulfurization denitration system jointly - Google Patents

Abstract

The utility model discloses a three-stage low-temperature flue gas desulfurization and denitrification combined system, wherein one end of a desulfurization reactor is communicated with a flue gas cooler, and the other end of the desulfurization reactor is sequentially communicated with a demister, a carbon-based adsorbent pretreatment reactor, a flue gas reheater and a denitrification reactor along the flue gas inflow direction. According to the three-stage low-temperature flue gas desulfurization and denitrification combined system, the flue gas is cooled and then is subjected to graded synergistic desulfurization and denitrification, the problem of high-temperature ignition is avoided, the performance of a carbon-based adsorbent for adsorbing NO is improved, the desulfurization effect of the carbon-based adsorbent is greatly improved, and SO in a first-stage reactor is used for removing sulfur and nitrogen₂The removal efficiency reaches more than 99 percent, and SO is avoided₂Adverse effect on NO removal in downstream reactors and reduction of NH formation₄HSO₄The risk of blocking the pores on the surface of the carbon-based adsorbent is high, the NO removal rate in the third-stage reactor reaches over 90 percent, high-efficiency desulfurization and denitrification are realized, and meanwhile, part of pollutants such as heavy metals, VOC (volatile organic compounds) and the like can be removed in a synergistic manner, so that the structure is simple, and the application prospect is wide.

Description

Tertiary flue gas low temperature is desulfurization denitration system jointly

Technical Field

The utility model belongs to the technical field of flue gas desulfurization and denitration, and particularly relates to a three-level flue gas low-temperature combined desulfurization and denitration system.

Background

With continuous ultralow emission modification in the power industry of China, the total emission of pollutants is continuously reduced, and the pollutants emitted by the non-power industries such as metallurgy and the like at present are key treatment objects for solving atmospheric pollution except for requirement SO₂And when the emission of pollutant gases such as NO reaches the standard, enterprises are also required to perform whitening treatment on the flue gas. The current enterprise flue gas white elimination technology generally adopts the mode of cooling and condensing the flue gas firstly and then heating the flue gas.

The dry desulfurization principle of active carbon/coke/carbon fiber (for convenience of description, hereinafter referred to as carbon-based adsorbent) is SO in flue gas₂Adsorbing and oxidizing in micropores on the surface of the carbon-based adsorbent to form H with water vapor in the flue gas₂SO₄(ii) a The denitration principle of the carbon-based adsorbent is that NO in the flue gas generates catalytic reduction reaction in micropores on the surface of the carbon-based adsorbent to generate N₂And H₂O。

When the carbon-based adsorbent is used for simultaneously desulfurizing and denitrating, NO and SO₂There is competitive adsorption in micropores on the carbon-based adsorbent surface due to SO₂More polar than NO, SO₂Has stronger inhibiting effect on NO adsorption of the carbon-based adsorbent. The carbon-based adsorbent can be simultaneously used for desulfurization and denitrification under the condition of no ammonia injection due to SO₂Can not realize high-efficiency removal, and SO in the flue gas₂Can inhibit the removal of NO, has low NO removal efficiency, causes the NO emission value to fail to meet the requirement of environmental protection emission, and has SO₂The removal efficiency is higher than that of NO, but SO₂The sorbent is penetrated very quickly. The carbon-based adsorbent is simultaneously desulfurized and denitrated under the condition of ammonia injection, the NO removal efficiency is still very low, and SO is generated₂The removal efficiency is greatly improved to more than 99 percent, but SO in the flue gas₂By oxidation of generated H₂SO₄Will react with NH₃Reaction to form highly viscous NH₄HSO₄，NH₄HSO₄When the smoke temperature is lower, the smoke gas is easy to adhere to the surface of the carbon-based adsorbent, and the pores on the surface of the carbon-based adsorbent are blocked, so that the activity of the carbon-based adsorbent is rapidly reduced, and the desulfurization and denitrification performance of the carbon-based adsorbent is greatly reduced.

After NO adsorption treatment, the carbon-based adsorbent adsorbs SO₂The performance of the device is greatly improved. The temperature rise can inhibit the carbon-based adsorbent from adsorbing SO₂The higher the temperature, the higher the SO of₂The lower the performance of (c). Independently removing SO from the carbon-based adsorbent after NO adsorption treatment at 40 ℃ without spraying ammonia₂The efficiency can reach more than 99%. While the smoke temperature is lowerIn the ammonia spraying condition, the removal efficiency of NO is lower, while the removal efficiency of the carbon-based adsorbent is increased along with the increase of the smoke temperature, and the denitration efficiency can reach more than 90 percent under the ammonia spraying condition. Although the denitration efficiency of the carbon-based adsorbent is improved due to the increase of the smoke temperature, the risk of ignition when the local smoke temperature reaches the ignition point is caused due to the overhigh smoke temperature.

Chinese patent publication No. CN110772983A discloses a device and method for low-temperature denitration of flue gas, and chinese patent publication No. CN209865768U discloses a dry flue gas desulfurization and denitration system with ammonia injected in different levels. The method is provided with two stages of reactors, and the inlets of the reactors are respectively provided with an ammonia spraying system, so that the functions of desulfurization and denitrification are respectively realized under the condition of ammonia spraying.

Due to SO₂The existence of the catalyst can obviously inhibit the adsorption and removal effects of the carbon-based adsorbent on NO, SO a two-stage reactor is generally arranged, and most of SO is removed by spraying ammonia in a first-stage reactor₂And then, spraying ammonia in the second-stage reactor to remove NO. Both Chinese patent CN102019135A and Chinese patent CN209865768U are provided with two-stage reactors, NH is arranged in the first-stage reactor₃Is easy to react with H₂SO₄Formation of high-viscosity NH₄HSO₄Plugging the pores on the surface of the catalyst in the reactor, causing rapid deactivation of the catalyst; on the other hand, the higher smoke temperature causes the higher loss of the carbon-based adsorbent, and the loss of the adsorbent is increased. Meanwhile, the risk that the local smoke temperature reaches the ignition point and ignition occurs exists.

SUMMERY OF THE UTILITY MODEL

In order to solve the technical problems in the prior art, the utility model aims to provide a three-stage flue gas low-temperature combined desulfurization and denitrification system.

In order to achieve the purpose and achieve the technical effect, the utility model adopts the technical scheme that:

the utility model provides a desulfurization denitration system is united to tertiary flue gas low temperature, is the tertiary reactor, includes first order reactor, second order reactor and third order reactor, first order reactor includes desulfurization reactor for SO in the desorption flue gas under the condition of not spouting ammonia₂The second stage reactor comprises carbonThe device comprises a base adsorbent pretreatment reactor, a first-stage reactor is provided with a desulfurized carbon-based adsorbent, a third-stage reactor comprises an ammonia spraying barrier and a denitration reactor and is used for removing NO in flue gas under the ammonia spraying condition, one end of the desulfurization reactor is communicated with a flue gas cooler, the other end of the desulfurization reactor is sequentially communicated with a demister, a carbon-based adsorbent pretreatment reactor, a flue gas reheater and a denitration reactor along the flue gas inflow direction, the ammonia spraying barrier is arranged between the flue gas reheater and the denitration reactor, a discharge port of the carbon-based adsorbent pretreatment reactor is communicated with a feed port of the carbon-based adsorbent pretreatment reactor, and the carbon-based adsorbent in the carbon-based adsorbent pretreatment reactor is subjected to NO adsorption treatment and is fed into the desulfurization reactor.

Furthermore, the desulfurization reactor is provided with a first feed inlet and a first discharge outlet, the carbon-based adsorbent pretreatment reactor is provided with a second feed inlet and a second discharge outlet, the first feed inlet is communicated with the second discharge outlet, and the carbon-based adsorbent in the carbon-based adsorbent pretreatment reactor sequentially enters the desulfurization reactor through the second discharge outlet and the first feed inlet after adsorbing NO.

Further, a flue gas analyzer at the inlet of the desulfurization reactor is arranged between the flue gas cooler and the desulfurization reactor.

Further, an inlet flue gas analyzer of the carbon-based adsorbent pretreatment reactor is arranged on a flue between the demister and the carbon-based adsorbent pretreatment reactor and used for detecting SO in flue gas₂And (4) concentration.

Further, an inlet flue gas analyzer and an ammonia spraying grid of the denitration reactor are sequentially arranged on a flue between the flue gas reheater and the denitration reactor from left to right.

Further, a denitration reactor outlet flue gas analyzer is arranged at the outlet of the denitration reactor.

Furthermore, the flue where the flue gas cooler and the desulfurization reactor are located is perpendicular to the flue where the demister is located, and the flue where the carbon-based adsorbent pretreatment reactor and the flue where the flue gas reheater are located is perpendicular to the flue where the demister is located.

The utility model provides a three-level low-temperature flue gas desulfurization and denitrification combined method, which comprises the following steps:

the temperature of the flue gas is reduced after passing through the flue gas cooler, and the flue gas enters a desulfurization reactor, SO in the flue gas₂Reacts with the carbon-based adsorbent in the desulfurization reactor to realize the reaction of SO in the flue gas₂Then, the flue gas passes through a demister to remove water and acid mist in the flue gas, enters a carbon-based adsorbent pretreatment reactor, and is subjected to SO detection in the flue gas by a flue gas analyzer at the inlet of the carbon-based adsorbent pretreatment reactor₂In the case of SO₂When the concentration exceeds a preset threshold value, feeding the carbon-based adsorbent subjected to NO adsorption treatment in the carbon-based adsorbent pretreatment reactor into a desulfurization reactor; heating the flue gas by a flue gas reheater, and spraying NO in the flue gas and NH sprayed by an ammonia spraying grid in a denitration reactor₃Reaction to form N₂And H₂And O, removing NO in the flue gas.

Compared with the prior art, the utility model has the beneficial effects that:

the utility model discloses a three-stage flue gas low-temperature combined desulfurization and denitrification system which is a three-stage reactor and comprises a first-stage reactor, a second-stage reactor and a third-stage reactor, wherein the first-stage reactor comprises a desulfurization reactor and is used for removing SO in flue gas under the condition of no ammonia injection₂The second-stage reactor comprises a carbon-based adsorbent pretreatment reactor which provides desulfurized carbon-based adsorbent for the first-stage reactor, the third-stage reactor comprises an ammonia spraying barrier and a denitration reactor which are used for removing NO in the flue gas under the ammonia spraying condition, one end of the desulfurization reactor is communicated with a flue gas cooler, the other end of the desulfurization reactor is sequentially communicated with a demister, a carbon-based adsorbent pretreatment reactor, a flue gas reheater and a denitration reactor along the flue gas inflow direction, the ammonia spraying barrier is arranged between the flue gas reheater and the denitration reactor, a discharge port of the carbon-based adsorbent pretreatment reactor is communicated with a feed port of the carbon-based adsorbent pretreatment reactor, and the carbon-based adsorbent in the carbon-based adsorbent pretreatment reactor is subjected to NO adsorption treatment and is fed into the desulfurization reactor. The three-stage low-temperature flue gas combined desulfurization and denitrification system provided by the utility model is combined with the current flue gas whitening process, and the flue gas is cooled by a flue gas cooler and then dividedThe stage-coordinated desulfurization and denitrification can avoid the problem that the local temperature of the carbon-based adsorbent is too high to reach the ignition point to ignite due to the heat release of the chemical reaction under the high-temperature condition; on the other hand, the performance of the carbon-based adsorbent for adsorbing NO is improved by temperature reduction, then the characteristic that the desulfurization performance of the carbon-based adsorbent can be greatly improved by adsorbing NO is utilized, the desulfurization effect of the carbon-based adsorbent can be greatly improved by arranging a carbon-based adsorbent pretreatment reactor in a flue, and SO in a first-stage reactor in a three-stage graded desulfurization and denitrification system₂The removal efficiency reaches more than 99 percent, and SO is avoided₂Adverse effects on NO removal in downstream reactors and reduction of NH in flue gas₃And H₂SO₄Reaction to form NH₄HSO₄The risk of blocking the pores on the surface of the carbon-based adsorbent, and the NO removal rate in the third-stage reactor can reach over 90 percent; and finally, the efficient desulfurization and denitrification can be realized, and meanwhile, part of pollutants such as heavy metals, VOC (volatile organic compounds) and the like can be removed in a synergistic manner.

Drawings

FIG. 1 is a schematic structural view of the present invention;

wherein, 1, a flue gas cooler; 2. an inlet flue gas analyzer of the desulfurization reactor; 3. a desulfurization reactor; 3a, a first feed inlet; 3b, a first discharge hole; 4. a demister; 5. an inlet flue gas analyzer of the carbon-based adsorbent pretreatment reactor; 6. a carbon-based adsorbent pretreatment reactor; 7. a flue gas reheater; 8. an inlet flue gas analyzer of the denitration reactor; 9. an ammonia injection grid; 10. a denitration reactor; 11. a denitration reactor outlet flue gas analyzer; 6a and a second feed inlet; 6b and a second discharge hole.

Detailed Description

The following detailed description of the embodiments of the present invention is provided to enable those skilled in the art to more easily understand the advantages and features of the present invention, and to clearly and clearly define the scope of the present invention.

As shown in figure 1, a three-stage flue gas low-temperature combined desulfurization and denitrification system is a three-stage reactor, is used for meeting the flue gas component conditions and the flue gas temperature conditions of graded high-efficiency desulfurization and denitrification, and mainly comprises a flue gas cooler 1 and a desulfurization reactionThe device comprises a device inlet flue gas analyzer 2, a desulfurization reactor 3, a demister 4, a carbon-based adsorbent pretreatment reactor inlet flue gas analyzer 5, a carbon-based adsorbent pretreatment reactor 6, a flue gas reheater 7, a denitration reactor inlet flue gas analyzer 8, an ammonia injection grid 9, a denitration reactor 10 and a denitration reactor outlet flue gas analyzer 11, wherein a first-stage reactor comprises the desulfurization reactor 3, and the first-stage reactor mainly passes through the carbon-based adsorbent in the desulfurization reactor 3 under the condition of no ammonia injection at low temperature to treat SO in flue gas₂The second-stage reactor comprises a carbon-based adsorbent pretreatment reactor 6, the second-stage reactor is mainly used for pretreating the carbon-based adsorbent to provide a high-efficiency desulfurization catalyst (carbon-based adsorbent) for the first-stage reactor, the third-stage reactor comprises an ammonia injection grid 9 and a denitration reactor 10, the third-stage reactor is mainly used for efficiently removing NO in the flue gas under the condition of ammonia injection, along the flowing direction of the flue gas, a flue gas cooler 1 is communicated with a desulfurization reactor 3 and then sequentially communicated with a demister 4, the carbon-based adsorbent pretreatment reactor 6, a flue gas reheater 7 and the denitration reactor 10, a desulfurization reactor inlet flue gas analyzer 2 is arranged on a flue between the flue gas cooler 1 and the desulfurization reactor 3, and a carbon-based adsorbent pretreatment reactor inlet flue gas analyzer 5 is arranged on a flue between the demister 4 and the carbon-based adsorbent pretreatment reactor 6, denitration reactor import flue gas analysis appearance 8 and ammonia injection grid 9 arrange in the flue between flue gas reheater 7 and denitration reactor 10 from left to right order, and ammonia injection grid 9 spouts the ammonia towards denitration reactor 10 in, and denitration reactor export flue gas analysis appearance 11 sets up in denitration reactor 10 exit position.

The upstream of the carbon-based adsorbent pretreatment reactor 6 is provided with a device for detecting SO in flue gas₂The inlet flue gas analyzer 5 of the carbon-based adsorbent pretreatment reactor with the concentration detects SO in the flue gas₂Or if the content exceeds the preset threshold value, the carbon-based adsorbent treated by adsorbing NO in the reactor 6 is pretreated by the carbon-based adsorbent as soon as possible to replace the carbon-based adsorbent in the desulfurization reactor 3, SO as to ensure that the performance of the carbon-based adsorbent in the desulfurization reactor 3 is enough to realize the purpose of adsorbing SO in the flue gas₂Is completely removed to avoid SO₂Enters the denitration reactor 10 to reduce SO on the one hand₂With NH in flue gas₃After the reaction, NH is formed₄HSO₄On the other hand to avoid SO₂Competing with NO for adsorption results in a decrease in NO removal efficiency.

Because the adsorption performance of the carbon-based adsorbent treated by adsorbing NO to partial heavy metal and VOC is correspondingly improved, partial heavy metal, VOC and other pollutants in the flue gas can also have a better removal effect in the desulfurization reactor 3 and the carbon-based adsorbent pretreatment reactor 6, and the system can also remove partial heavy metal, VOC and other pollutants in a synergistic manner while performing synergistic desulfurization and denitrification.

The desulfurization and denitrification method comprises the following steps:

the temperature of the flue gas is greatly reduced (below 40 ℃) after passing through the flue gas cooler 1, and then the flue gas enters the desulfurization reactor 3, and SO in the flue gas in the desulfurization reactor 3₂Reacts with the carbon-based adsorbent treated by adsorbing NO to realize the reaction of SO in the flue gas₂The flue gas is subjected to the demister 4 to remove part of water and acid mist in the flue gas, and then the flue gas enters a carbon-based adsorbent pretreatment reactor 6; the carbon-based adsorbent enters the carbon-based adsorbent pretreatment reactor 6 through a second feed port 6a of the carbon-based adsorbent pretreatment reactor 6, and the carbon-based adsorbent is subjected to NO adsorption treatment in the carbon-based adsorbent pretreatment reactor 6: when the flue gas flows through the first-stage reactor, SO in the flue gas is removed₂When the flue gas passes through the carbon-based adsorbent in the second-stage reactor (carbon-based adsorbent pretreatment reactor 6), almost no SO is contained in the flue gas₂Competitive adsorption with NO, at the moment, NO can be adsorbed on the surface of the carbon-based adsorbent in a large amount and then oxidized by surface functional groups or oxygen in the flue gas, and NO is adsorbed and oxidized on the surface of micropores of the carbon-based adsorbent material and then is adsorbed and oxidized to SO₂The capacity of the desulfurization reactor is greatly improved, the carbon-based adsorbent subjected to NO adsorption treatment is discharged from a second discharge port 6b of the carbon-based adsorbent pretreatment reactor 6 and then is added into the desulfurization reactor 3 through a first feed port 3a of the desulfurization reactor 3, so that the desulfurization efficiency is improved; the temperature of the flue gas is increased (above 90 ℃) after passing through the flue gas reheater 7, and NH is sprayed into the flue by the ammonia spraying grid 9₃NOx in the flue gas in the denitration reactor 10 and NH sprayed by the ammonia spraying grid 9₃Reaction ofGenerating N₂And H₂And O, realizing the high-efficiency removal of NO in the flue gas.

The parts of the utility model not specifically described can be realized by adopting the prior art, and the details are not described herein.

The above description is only an embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications of equivalent structures and equivalent processes performed by the present specification and drawings, or directly or indirectly applied to other related technical fields, are included in the scope of the present invention.

Claims (7)

1. A three-stage flue gas low-temperature combined desulfurization and denitrification system is characterized by being a three-stage reactor and comprising a first-stage reactor, a second-stage reactor and a third-stage reactor, the first-stage reactor comprises a desulfurization reactor, the second-stage reactor comprises a carbon-based adsorbent pretreatment reactor, the third-stage reactor comprises an ammonia spraying barrier and a denitration reactor, one end of the desulfurization reactor is communicated with a flue gas cooler, the other end of the desulfurization reactor is sequentially communicated with a demister, the carbon-based adsorbent pretreatment reactor, a flue gas reheater and the denitration reactor along the flue gas inflow direction, the ammonia spraying barrier is arranged between the flue gas reheater and the denitration reactor, the discharge port of the carbon-based adsorbent pretreatment reactor is communicated with the feed inlet of the carbon-based adsorbent pretreatment reactor, the carbon-based adsorbent in the desulfurization reactor is treated by adsorbing NO through the carbon-based adsorbent pretreatment reactor and is sent into the desulfurization reactor.

2. The system of claim 1, wherein the desulfurization reactor is provided with a first feeding port and a first discharging port, the carbon-based adsorbent pretreatment reactor is provided with a second feeding port and a second discharging port, the first feeding port is communicated with the second discharging port, and the carbon-based adsorbent in the carbon-based adsorbent pretreatment reactor sequentially enters the desulfurization reactor through the second discharging port and the first feeding port after being subjected to NO adsorption treatment.

3. The system of claim 1, wherein a desulfurization reactor inlet flue gas analyzer is disposed between the flue gas cooler and the desulfurization reactor.

4. The system of claim 1, wherein an inlet flue gas analyzer of the carbon-based adsorbent pretreatment reactor is arranged in a flue between the demister and the carbon-based adsorbent pretreatment reactor.

5. The three-stage low-temperature flue gas desulfurization and denitrification combined system according to claim 1, wherein an inlet flue gas analyzer and an ammonia injection grid of the denitrification reactor are sequentially arranged on a flue between the flue gas reheater and the denitrification reactor from left to right.

6. The system of claim 1, wherein a denitration reactor outlet flue gas analyzer is disposed at the outlet of the denitration reactor.

7. The system of claim 1, wherein the flue of the flue gas cooler and the flue of the desulfurization reactor are perpendicular to the flue of the demister, and the flue of the carbon-based adsorbent pretreatment reactor and the flue of the flue gas reheater are perpendicular to the flue of the demister.

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