CN219272656U

CN219272656U - Processing system for deep dust removal of industrial boiler flue gas

Info

Publication number: CN219272656U
Application number: CN202223561237.6U
Authority: CN
Inventors: 田高峰; 王小立; 沈滨; 许璐; 韩祥
Original assignee: Beijing Longyuan Environmental Engineering Co ltd
Current assignee: Beijing Longyuan Environmental Engineering Co ltd
Priority date: 2022-12-30
Filing date: 2022-12-30
Publication date: 2023-06-30
Anticipated expiration: 2032-12-30

Abstract

The utility model discloses a treatment system for deeply removing dust of industrial boiler flue gas, which comprises an air inlet pipeline of a bag type dust collector and a boiler exhaust portA first ammonia spraying device is arranged in a pipeline between the bag type dust collector and the boiler, an air outlet pipeline of the bag type dust collector is communicated with a first air inlet pipeline of the heat exchanger, the first air outlet pipeline of the heat exchanger is communicated with an air inlet pipeline of the heater, the air outlet pipeline of the heater is communicated with the first air inlet pipeline at the top end of the denitration reactor, a second ammonia spraying device is arranged in a pipeline between the heater and the denitration reactor, an air outlet pipeline at the bottom end of the denitration reactor is communicated with a second air inlet pipeline of the heat exchanger, and the second air outlet pipeline of the heat exchanger is communicated with an air inlet pipeline of the wet desulfurization tower. The utility model arranges the denitration reactor at the downstream of the dust remover, and sprays ammonia and SO before the dust remover ₃ The product after the reaction with ammonia is ammonium sulfate or ammonium bisulfate, and is captured and intercepted along with smoke dust by a bag type dust collector, so that the content of sulfide in discharged smoke is effectively reduced.

Description

Processing system for deep dust removal of industrial boiler flue gas

Technical Field

The utility model relates to the technical field of boiler flue gas treatment, in particular to a treatment system for deep dust removal of industrial boiler flue gas.

Background

SO in industrial boiler flue gas ₃ The safe operation of the unit is affected, and the pollution to the surrounding atmospheric environment is also caused. At present, the common flue gas treatment flow is that the flue gas sequentially passes through a denitration reactor, an air preheater, a dust remover and a wet desulfurization tower. The scrubbing action of the wet desulfurizing tower has high efficiency for removing sulfur dioxide in the flue gas, but has low SO content in the flue gas ₃ The effect is poor, and the removal rate is only about 20-30%. After the flue gas passes through the wet desulfurization tower, the humidity of the flue gas is increased, the temperature is reduced, and the water vapor and SO in the flue gas ₃ Can be condensed into fog drops, forms dilute sulfuric acid liquid with strong corrosiveness, and causes corrosion to downstream flues and chimneys. SO (SO) ₃ Specific SO ₂ Is more toxic and highly corrosive, and can form acid rain when discharged into the atmosphere. In case of reduced flue gas temperature, SO ₃ Condensing to form submicron acid mist, and reacting with alkaline substances in the atmosphere after discharging to generate a large amount of secondary sulfate fine particles, wherein the sulfate fine particles have strong extinction effect in the atmosphere, so that visibility is reduced and haze is increased.

At present, the nitrogen oxide removal technology applied to industrial boiler flue gas in China is most commonIs to adopt a Selective Catalytic Reduction (SCR) flue gas denitration technology. In addition to the catalytic reduction of nitrogen oxides in the denitration reactor, two other chemical reactions occur: the catalyst used in the denitration reactor promotes SO in the flue gas ₂ Conversion to SO ₃ Generally about 1%; in addition, SO ₃ Under the catalysis of the denitration catalyst, the catalyst reacts with ammonia serving as a denitration reducing agent to generate products such as ammonia sulfate, ammonia bisulfate and the like.

The traditional process flow is that the flue gas flows through the economizer and then sequentially enters the denitration reactor, the air preheater, the dust remover and the desulfurizing tower to be discharged through a chimney. However, the method can not effectively remove SO in the flue gas before the flue gas enters the denitration reactor ₃ Thus, it is difficult to avoid SO in flue gas ₃ After flowing through the denitration reactor, the wastewater can be converted into products such as ammonia sulfate, ammonia bisulfate and the like. This causes a significant amount of phase change of the ammonium sulfate and ammonium bisulfate materials in subsequent equipment, such as in the air preheater, which results in corrosion of the deposited plugs of ammonium sulfate and ammonium bisulfate and damage to subsequent flues and equipment.

Disclosure of Invention

The utility model aims to provide a treatment system for deeply removing dust in industrial boiler flue gas, which can effectively remove SO in the flue gas ₃ And generated ammonium sulfate, ammonium bisulfate and other substances, thereby reducing the acid pollution in the discharged flue gas.

The utility model provides a treatment system for deeply removing dust from industrial boiler flue gas, which comprises a first ammonia spraying device, a bag type dust collector, a heat exchanger, a heater, a second ammonia spraying device, a denitration reactor and a wet desulfurization tower, wherein an air inlet pipeline of the bag type dust collector is communicated with a boiler exhaust port and is used for introducing discharged raw flue gas; be equipped with in the pipeline between bag collector and the boiler first ammonia spraying device, bag collector's the pipeline of giving vent to anger with the first inlet channel intercommunication of heat exchanger, the first inlet channel intercommunication of giving vent to anger of heat exchanger and heater, the pipeline of giving vent to anger of heater with be located the first inlet channel intercommunication on denitration reactor top, be provided with in the pipeline between heater and the denitration reactor second ammonia spraying device, be located the pipeline of giving vent to anger of denitration reactor bottom with the second inlet channel intercommunication of heat exchanger, the second pipeline of giving vent to anger of heat exchanger with the inlet channel intercommunication of the bottom of wet flue gas desulfurization tower, the upper end of wet flue gas desulfurization tower is provided with condensing type defroster, and the flue gas is followed after desulfurization is located the upper end gas outlet of wet flue gas desulfurization tower discharges.

Further, the heat exchanger adopts a gas-gas heat exchanger.

Compared with the prior art, the utility model has the advantages that: the design adopts reasonable arrangement, the denitration reactor is arranged at the downstream of the dust remover, ammonia is sprayed in front of the dust remover, the product after the reaction of sulfur trioxide and ammonia is ammonium sulfate or ammonium bisulfate, and the product is captured and intercepted along with smoke dust by the bag type dust remover, SO that SO is removed in front of the denitration reactor ₃ Thereby controlling the generation amount of ammonium sulfate and ammonium bisulfate in the denitration reactor and effectively reducing the content of sulfide in the discharged flue gas. Meanwhile, in the desulfurization process of the flue gas through the wet desulfurization tower, ammonium salt in the flue gas is partially removed due to the washing effect of the wet desulfurization tower, and the ammonium salt in the flue gas is captured through the condensation type demister, so that the deposition of ammonium sulfate and ammonium bisulfate in the denitration reaction is reduced, the damage to a subsequent flue and equipment is avoided, and the service life of the equipment is prolonged.

Drawings

FIG. 1 is a schematic diagram of the overall structure of a treatment system for deep dust removal of industrial boiler flue gas;

wherein, 1-boiler, 2-first ammonia spraying device, 3-bag collector, 4-heat exchanger, 5-heater, 6-second ammonia spraying device, 7-denitration reactor, 8-wet flue gas desulfurization tower, 9-condensing defroster, 10-desulfurizing tower discharge port.

Detailed Description

In the following, in order to facilitate the understanding of the technical solutions of the present utility model by a person skilled in the art, reference will be made to the accompanying drawings for further description. It should be understood that the description is only illustrative and is not intended to limit the scope of the utility model.

In the following detailed description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the embodiments of the utility model. It may be evident, however, that one or more embodiments may be practiced without these specific details. In addition, in the following description, descriptions of well-known structures and techniques are omitted so as not to unnecessarily obscure the present utility model.

The utility model adopts the mode of reasonably arranging the bag type dust collector, the denitration reactor and the desulfurizing tower to remove SO by spraying ammonia before the bag type dust collector ₃ The method provides a system which has reasonable design, safe operation and economical and efficient removal of SO in the flue gas ₃ Is a system of (a).

Referring to fig. 1, a schematic diagram of an overall structure of a treatment system for deep dust removal of flue gas of an industrial boiler according to the present utility model includes a first ammonia spraying device 2, a bag type dust collector 3, a heat exchanger 4, a heater 5, a second ammonia spraying device 6, a denitration reactor 7 and a wet desulfurization tower 8, wherein an air inlet pipeline of the bag type dust collector 3 is communicated with an air outlet of the boiler 1 for introducing raw flue gas discharged from the boiler 1; the first ammonia spraying device 2 is arranged in a pipeline between the bag type dust collector 3 and the boiler 1, an air outlet pipeline of the bag type dust collector 3 is communicated with a first air inlet pipeline of the heat exchanger 4, and when the method is implemented, the filter bag material of the bag type dust collector 3 can be selected to be a proper fiber material according to the flue gas temperature, and the heat exchanger 4 adopts an air-air heat exchanger. The first air outlet pipeline of the heat exchanger 4 is communicated with the air inlet pipeline of the heater 5, the air outlet pipeline of the heater 5 is communicated with the first air inlet pipeline positioned at the top end of the denitration reactor 7, and the heater 5 can be an electric heater, a steam heater, a gas heater and the like. A second ammonia spraying device 6 is arranged in a pipeline between the heater 5 and the denitration reactor 7, an air outlet pipeline positioned at the bottom end of the denitration reactor 7 is communicated with a second air inlet pipeline of the heat exchanger 5, and a second air outlet pipeline of the heat exchanger 4 is communicated with an air inlet pipeline at the bottom end of the wet desulfurization tower 8. In this embodiment, the absorbent in the wet desulfurization tower 8 may be limestone or seawater, and the ammonium salt particles in part of the flue gas can be removed while sulfur dioxide in the flue gas is removed by the washing action of slurry. The upper end of wet flue gas desulfurizing tower 8 is provided with condensing defroster 9, and condensing defroster 9 comprises multiunit condenser water pipe, and intraductal cooling water that leads to, and the cooling water temperature is less than flue gas temperature, and the pipe surface forms one deck condensation water film, at the in-process with flue gas contact, can entrapment droplet and the particulate matter that carries in the flue gas to can effectually entrapment ammonium salt particulate matter, effectively reduce the smoke and dust emission content of system. The flue gas is discharged from an exhaust port 10 positioned at the upper end of the wet desulfurization tower 8 after desulfurization.

In specific operation, raw flue gas from the boiler 1 is mixed with ammonia sprayed by the first ammonia spraying device 2 in a flue, and the flue gas enters the bag filter 3 for reaction to enable SO ₃ The product after the reaction with ammonia is ammonium salt such as ammonium sulfate or ammonium bisulfate, and the total content of the ammonium salt is low but the particle size is small. The fly ash particles in the flue gas have high content and large specific surface area, so that the ammonium salt can be adsorbed. The flow velocity of the flue gas in the bag type dust collector 3 is low, the residence time is long, and the ammonia and SO can be ensured ₃ Is fully reacted to realize SO removal ₃ Is a target of (a). The fly ash particles adsorbed with ammonium salt in the flue gas are captured by a filter bag of a bag type dust collector and solidified into the fly ash, and are discharged through an ash bucket at the lower part of the dust collector, SO that SO in the flue gas is removed in the bag type dust collector 3 ₃ Is a target of (a).

In the specific implementation, the ammonia sprayed in the first ammonia spraying device 2 may be gaseous ammonia or ammonia water with an ammonia content of 20%. Ammonia usage and intended SO removal ₃ The molar ratio of (2) is generally controlled between 2 and 4. The excessive unreacted ammonia flows into the subsequent denitration reactor and can be used as a denitration reducing agent, so that the system is not adversely affected.

The flue gas flows out from the outlet of the bag type dust collector 3, enters the heat exchanger 4, enters the heater 5 after being heated in the heat exchanger 4, and the temperature of the flue gas gradually rises to reach the proper temperature of the denitration catalyst. In general, the temperature of the outlet of the bag filter 3 is 120-200 ℃ which is less than the reaction temperature of the catalyst, the temperature is increased to about 250 ℃ through the heat exchanger 4, and then the flue gas is continuously heated through the heater 5, and the temperature of the flue gas is increased to more than 280 ℃, so that the operation temperature of the catalyst in the denitration reactor 7 is met. At this time, the second ammonia spraying device 6 in the flue sprays ammonia needed by the denitration reaction into the flue, the ammonia and the nitrogen oxides in the flue gas react in the denitration reactor 7 after being uniformly mixed, the purpose of removing the nitrogen oxides is achieved by the ammonia serving as a reducing agent reacting with the nitrogen oxides in the flue gas, the flue gas after denitration enters the heat exchanger 4 again, the temperature is reduced to about 150 ℃, and the heat exchanger 4 transmits high-temperature heat to the flue gas at the inlet of the denitration reactor so as to save energy. Because the flue gas entering the heat exchanger 4 is dedusted, the possibility of ash accumulation and blockage in the heat exchanger 4 is avoided.

Then enters a wet desulfurization tower 8, a desulfurization reaction is carried out in the wet desulfurization tower 8, the flue gas flows through a condensing dust remover 9, solid pollutants such as ammonium bisulfate and the like in the flue gas are further trapped in the condensing dust remover 9, and finally the flue gas is discharged through an exhaust port 10 at the top end of the wet desulfurization tower after purification treatment.

SO in flue gas due to catalyst of denitration reactor ₂ Conversion to SO ₃ Catalytic, converted SO ₃ Reacts with ammonia to generate ammonium salt particles such as ammonia sulfate, ammonia bisulfate and the like. In the process that the flue gas passes through the subsequent wet desulfurization tower 8, ammonium salt in the flue gas is partially removed due to the washing effect of the wet desulfurization tower, and in the process that the flue gas passes through the condensation type demister 9, the ammonium salt is trapped by the demister along with fog drops in the flue gas.

In summary, the utility model removes SO before the bag filter 3 ₃ The byproducts such as ammonium sulfate, ammonium bisulfate and the like can be captured by the bag dust collector, so that the corrosion of ammonium salt to equipment is avoided. In addition, the ammonia is adopted as the absorbent of sulfur trioxide, and is consistent with the ammonia source for denitration, a supply system of the absorbent such as alkali solution is not needed to be additionally arranged, the system is simple to be arranged, and industrial application is easy to realize. The utility model can trap a small amount of ammonia sulfate and ammonia bisulfate generated in the denitration reactor, effectively reduce the content of ammonium sulfate and ammonia bisulfate particles in the flue gas, and finally reduce the content of smoke dust discharged by the system.

The above examples are only illustrative of the preferred embodiments of the present utility model and are not intended to limit the scope of the present utility model, and various modifications and improvements made by those skilled in the art to the technical solution of the present utility model should fall within the scope of protection defined by the claims of the present utility model without departing from the spirit of the present utility model.

Claims

1. The treatment system for deeply removing dust from the flue gas of the industrial boiler is characterized by comprising a first ammonia spraying device (2), a bag type dust collector (3), a heat exchanger (4), a heater (5), a second ammonia spraying device (6), a denitration reactor (7) and a wet desulfurization tower (8), wherein an air inlet pipeline of the bag type dust collector (3) is communicated with an air outlet of the boiler (1) and is used for introducing raw flue gas exhausted by the boiler (1); be equipped with in the pipeline between bag collector (3) and boiler (1) first ammonia injection device (2), the pipeline of giving vent to anger of bag collector (3) with the first inlet channel intercommunication of heat exchanger (4), the first inlet channel intercommunication of the first outlet channel of heat exchanger (4) and heater (5), the pipeline of giving vent to anger of heater (5) with be located the first inlet channel intercommunication on denitration reactor (7) top, be provided with in the pipeline between heater (5) and denitration reactor (7) second ammonia injection device (6), be located the pipeline of giving vent to anger of the bottom of denitration reactor (7) with the second inlet channel intercommunication of heat exchanger (4), the second outlet channel of heat exchanger (4) with the inlet channel intercommunication of the bottom of wet flue gas desulfurization tower (8), the upper end of wet flue gas desulfurization tower (8) is provided with condensing defroster (9), and the flue gas is located after being located the gas outlet of wet flue gas desulfurization tower (8).

2. The treatment system for deep dedusting of industrial boiler flue gas according to claim 1, wherein the heat exchanger (4) is a gas-gas heat exchanger.