CN212119530U

CN212119530U - Lime kiln exhaust gas desulfurization and denitrification system

Info

Publication number: CN212119530U
Application number: CN202020518286.3U
Authority: CN
Inventors: 吕文彬; 沈先锋; 周赟; 訾朝辉
Original assignee: Anhui Fangxin Lihua Environmental Protection Technology Co ltd; Tongxing Environmental Protection Technology Co ltd
Current assignee: Anhui Fangxin Lihua Environmental Protection Technology Co ltd; Tongxing Environmental Protection Technology Co ltd
Priority date: 2020-04-08
Filing date: 2020-04-08
Publication date: 2020-12-11
Anticipated expiration: 2030-04-08

Abstract

The utility model discloses a lime kiln waste gas desulfurization deNOx systems, including dry desulfurization tower, sack cleaner, low temperature SCR deNOx systems and booster fan. The exhaust end of the dry desulfurization tower is connected to the air inlet end of the bag-type dust remover, the exhaust end of the bag-type dust remover is connected to the air inlet end of the low-temperature SCR denitration system, and the exhaust end of the low-temperature SCR denitration system is connected to the air inlet end of the booster fan. This lime kiln exhaust gas desulfurization deNOx systems realizes dust, SO in high-efficient desorption flue gas₂And the purpose of low-temperature SCR denitration, no secondary pollution in the system operation process, convenient maintenance, simple device, easy operation and low energy consumption.

Description

Lime kiln exhaust gas desulfurization and denitrification system

Technical Field

The utility model relates to a flue gas desulfurization, dust removal and deNOx systems technical field specifically are a limekiln waste gas desulfurization deNOx systems.

Background

With the continuous deepening of the industrialization process of China, serious atmospheric pollution and acid rain are formed in certain areas in China. This is because a large amount of harmful fumes and harmful gases, such as sulfur dioxide and various nitrogen-containing compounds, are discharged during production work due to industries such as coal burning. SO in recent years₂、NO_xThe pollution even exceeds that of smoke dust, and the smoke dust becomes the first large pollutant of the atmospheric environment. For long-term development later, the pollution treatment strength of China is continuously increased, and the environmental-friendly discharge standard is also getting tighter and tighter.

In recent years, the steel industry, the calcium carbide industry, the alumina industry, the refractory material industry and other industries are developed at a high speed, so that the lime needs to be supplied and demanded. Lime kiln plants in various places stand like chimneys like bamboo shoots in spring after rain, but some enterprises have weak environmental awareness and weak regulation and control force, and serious air pollution is caused. Under the high pressure situation that the country advocates environmental protection and energy saving, the pollution control of the lime kiln is not slow enough. According to the NO in DB 37/2375-2013-2018 'emission standard of atmospheric pollutants in local industrial kilns in Shandong province' and '2018' ultra-low emission requirement of desulfurization, denitrification and dust removal in non-electric industry of local environmental protection agency 'and' 2018_xThe emission concentration requirement meets the requirement of industrial kilnFurnace atmosphere pollution emission standard ": SO (SO)₂≤50mg/m³；NO_x≤150mg/m³(ii) a The particle is less than or equal to 10mg/m³。

The existing flue gas filtering system is difficult to simultaneously meet the requirements of efficient desulfurization, dust removal and denitration, and can cause secondary pollution. Meanwhile, other independent desulfurization, dust removal and denitration in the current market are simply integrated together, so that the defects of high energy consumption, large occupied area and complex equipment operation are overcome. Through detection, Chinese patent 201720677430.6, the name is: the utility model provides a lime kiln is with dust removal desulfurization system, this application includes circulating water tank, and circulating water tank's front and back both sides all are provided with one set of dust removal desulfurization system, and every set of dust removal desulfurization system's the outside all is provided with multirow lime kiln. The dedusting and desulfurizing system comprises cyclone dust collectors, bag type dust collectors, an induced draft fan and a desulfurizing tower which are sequentially arranged along the left and right directions, wherein the inlets of the cyclone dust collectors are communicated with the outlets of the main smoke exhaust pipes, and the inlets of the main smoke exhaust pipes are communicated with branch smoke exhaust pipes arranged on each row of lime kilns. The outlet of the cyclone dust collector is communicated with the inlet of the bag type dust collector, the outlet of the bag type dust collector is communicated with the inlet of the desulfurizing tower through the induced draft fan, and the desulfurizing tower is connected with the circulating water tank. However, the wet desulphurization in the application can generate wastewater to cause secondary pollution, does not remove nitrogen oxides in flue gas at the same time, cannot achieve the purpose of desulphurization, dedusting and denitration at the same time, and cannot meet increasingly strict environmental protection requirements.

In addition, the temperature of the exhaust gas at the outlet of the preheater is low, so that the energy consumption is increased in order to avoid reheating in the denitration process. Therefore, the method has the advantages of low energy consumption, simple device, easy operation and capability of efficiently removing pollutants in the flue gas by the aid of the low-temperature denitration desulfurization and denitration equipment. The method not only meets the market demand, but also contributes to the environmental protection industry.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a lime kiln exhaust gas desulfurization deNOx systems realizes dust, SO in the high-efficient desorption flue gas₂The aim of low-temperature SCR denitration is fulfilled, secondary pollution is avoided in the system operation process, the device has the advantages of convenience in maintenance, simplicity in device, easiness in operation and low energy consumption, and the problem in the prior art can be solvedTo a problem of (a).

In order to achieve the above object, the utility model provides a following technical scheme:

the utility model discloses a lime kiln waste gas desulfurization denitration system, for realizing the purpose that SOx/NOx control removed dust, including dry desulfurization tower, sack cleaner, low temperature SCR deNOx systems, booster fan, lime kiln waste gas SO₂The content is not high, dry desulfurization is adopted, and because the outlet temperature of a preheater is lower in the production process of a lime kiln, in order to avoid the increase of energy consumption caused by reheating flue gas, a low-temperature SCR denitration catalyst is adopted to catalyze and remove NO in the flue gas_x. However, SO in the exhaust gas is taken into account₂And alkali metals, alkaline earth metals and heavy metals in the flue gas dust have larger blocking and poisoning effects on the low-temperature SCR denitration catalyst, so that the desulfurization tower and the bag-type dust remover are arranged at the upstream of the denitration reactor. The exhaust end of the dry desulfurization tower is connected to the air inlet end of the bag-type dust remover, the exhaust end of the bag-type dust remover is connected to the air inlet end of the low-temperature SCR denitration system, and the exhaust end of the low-temperature SCR denitration system is connected to the air inlet end of the booster fan. The dry-method desulfurization tower comprises a grinding and conveying system, a venturi and a desulfurization tower straight body, wherein the output end of the grinding and conveying system is connected with the input end of the venturi, and the output end of the venturi is connected with the input end of the desulfurization tower straight body. The bag-type dust collector comprises a bag, a blowing system and an ash bucket, wherein the spraying end of the blowing system is connected to the inner cavity of the bag, the input end of the ash bucket is connected to the dust exhaust end of the bag, the bag-type dust collector further comprises an ash conveying system and an ash storage bin, the input end of the ash conveying system is connected to the output end of the ash bucket, and the input end of the ash storage bin is connected to the output end of the ash conveying system.

Preferably, the low-temperature SCR denitration system comprises a denitration reactor shell, an auxiliary heating system, an ammonia injection grid, a guide plate, a flue gas homogenizing module and a denitration catalyst. The auxiliary heating system, the ammonia injection grid, the guide plate and the flue gas homogenizing module are sequentially arranged at the input end in the denitration reactor shell, and the denitration catalyst is arranged at a straight body part in the denitration reactor shell.

Compared with the prior art, the beneficial effects of the utility model are as follows:

this lime kiln exhaust gas desulfurization deNOx systems adopts dry process desulfurization, has practiced thrift the cost, through low temperature SCR deNOx systems, has solved that preheater outlet flue gas temperature is lower in the past and is difficult to high-efficient desorption NO_xThe problem of (2) also avoids resource waste caused by waste gas reheating denitration. Meanwhile, the dry desulfurization tower and the bag-type dust remover are arranged at the upstream of the low-temperature SCR denitration system, SO that dust and SO in the waste gas can be effectively reduced₂The blockage and poisoning effects of the alkali metal, the alkaline earth metal and the heavy metal on the denitration catalyst increase the service life of the catalyst, and the system also has the advantages of simple structure, low investment and no secondary pollution.

Drawings

FIG. 1 is a system architecture diagram of the present invention;

FIG. 2 is a system diagram of a dry desulfurization tower according to the present invention;

FIG. 3 is a system diagram of the bag-type dust collector of the present invention;

figure 4 is the utility model discloses a low temperature SCR deNOx systems map.

In the figure: 1. a dry desulfurization tower; 11. a mill and delivery system; 12. a venturi; 13. a straight body of the desulfurization tower; 2. a bag-type dust collector; 21. a cloth bag; 22. a blowing system; 23. an ash hopper; 24. an ash conveying system; 25. an ash storage bin; 3. a low-temperature SCR denitration system; 31. a denitrification reactor housing; 32. an auxiliary heating system; 33. an ammonia injection grid; 34. a baffle; 35. a flue gas homogenizing module; 36. a denitration catalyst; 4. a booster fan.

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 work belong to the protection scope of the present invention.

Referring to fig. 1, a lime kiln exhaust gas desulfurization and denitrification system includes a dry desulfurization tower 1, a bag-type dust collector 2, a low-temperature SCR denitrification system 3, and a booster fan 4. The end of giving vent to anger of dry desulfurization tower 1 is connected in the inlet end of sack cleaner 2, and the end of giving vent to anger of sack cleaner 2 is connected in the inlet end of low temperature SCR deNOx systems 3, and the end of giving vent to anger of low temperature SCR deNOx systems 3 is connected in the inlet end of booster fan 4.

Referring to fig. 2, the dry desulfurization tower 1 further includes a grinding and conveying system 11, a venturi 12 and a desulfurization tower body 13, wherein an output end of the grinding and conveying system 11 is connected to an input end of the venturi 12, and an output end of the venturi 12 is connected to an input end of the desulfurization tower body 13. Wherein, the grinding and conveying system 11 is used for grinding and conveying the desulfurizer; the venturi 12 is used to accelerate the gas-solid phase mixing and desulfurization in the desulfurization tower body 13.

Referring to fig. 3, the bag-type dust collector 2 further includes a bag 21, a blowing system 22 and an ash bucket 23, wherein a blowing end of the blowing system 22 is connected to an inner cavity of the bag 21, and an input end of the ash bucket 23 is connected to a dust exhaust end of the bag 21. The cloth bag 21 is used for trapping desulfurized ash and dust in the waste gas, and simultaneously reducing blockage and poisoning of the desulfurized ash and dust to a catalyst in a subsequent denitration reactor. The blowing system 22 is used for regularly cleaning dust deposited on the cloth bag 21 to prevent blockage; the dust hopper 23 is used for storing dust cleaned by blowing.

The bag-type dust collector 2 further comprises an ash conveying system 24 and an ash storage bin 25, wherein the input end of the ash conveying system 24 is connected to the output end of the ash hopper 23, and the input end of the ash storage bin 25 is connected to the output end of the ash conveying system 24. Wherein, the ash conveying system 24 is used for conveying the dust discharged from the ash bucket 23; the dust storage bin 25 is used for temporarily storing dust and waiting for outward transportation.

Referring to fig. 4, the low-temperature SCR denitration system 3 includes a denitration reactor shell 31, an auxiliary heating system 32, an ammonia injection grid 33, a guide plate 34, a flue gas homogenizing module 35, and a denitration catalyst 36. The auxiliary heating system 32, the ammonia injection grid 33, the guide plate 34 and the flue gas homogenizing module 35 are sequentially arranged at the input end in the denitration reactor shell 31, and the denitration catalyst 36 is arranged at a straight body part in the denitration reactor shell 31. Wherein the auxiliary heating system 32 is used for heating (NH) on the surface of the desorption catalyst₄)₂SO₄And NH₄HSO₄So that the catalyst keeps higher catalytic activity. The ammonia injection grid 33 is used for dispersing the injected ammonia gas. The guide plate 34 and the flue gas homogenizing module 35 are used for guiding the mixed gas flow, so that the gas flow is mixed more uniformly and fully. The denitration catalyst 36 is used for catalyzing the mixed gas flow to achieve the purpose of low-temperature denitration, and the catalysis principle is NH₃With NO_XAnd O₂Reaction to form H₂O and N₂. The booster fan 4 is used for providing power for flue gas flowing and sending the processed clean flue gas into a chimney for discharging.

The system work flow is as follows:

waste gas generated in the production process enters a dry-method desulfurizing tower 1, a desulfurizing agent is firstly ground into a required mesh number by a grinding and conveying system 11 and is injected into the system to be mixed with the waste gas, then the mixture is further fully mixed by a venturi 12, and SO in the waste gas₂Reacts with a desulfurizer in the straight body 13 of the desulfurizing tower to achieve the effect of high-efficiency desulfurization.

The desulfurized waste gas enters the bag-type dust collector 2, the dust is intercepted on the surface of the filter bag through the filtering and purifying effect of the bag 21, and the dust falls into the dust hopper 23 under the blowing of the blowing system 22 and enters the dust storage bin 25 through the dust conveying system 24 to wait for outward transportation.

The low-sulfur and low-dust flue gas obtained after the desulfurization and dust removal of the waste gas enters the low-temperature SCR denitration system 3, the waste gas and the sprayed ammonia-air mixed gas are fully rectified and mixed by the guide plate 34 and the flue gas homogenizing module 35, and NO is added under the action of the denitration catalyst 36_xIs removed. Meanwhile, the auxiliary heating system 32 is arranged to heat (NH) on the surface of the desorption catalyst₄)₂SO₄And NH₄HSO₄So that the catalyst keeps higher catalytic activity.

High-efficiency removal of dust and SO in waste gas₂And NO_xThe clean flue gas is sent into a chimney through a booster fan 4 to be discharged.

In summary, the following steps: this lime kiln exhaust gas desulfurization deNOx systems adopts dry desulfurization, has practiced thrift the cost, through low temperature SCR deNOx systems 3, has solved that preheater outlet flue gas temperature is lower in the past and is difficult to high-efficient desorption NO_xThe problem of (2) also avoids resource waste caused by waste gas reheating denitration. Meanwhile, the dry desulfurization tower 1 and the bag-type dust collector 2 are arranged at the upstream of the low-temperature SCR denitration system 3, SO that dust and SO in waste gas can be effectively reduced₂The blockage and poisoning effects of the alkali metal, the alkaline earth metal and the heavy metal on the denitration catalyst 36 increase the service life of the catalyst, and the system also has the advantages of simple structure, low investment and no secondary pollution.

It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims

1. A lime kiln waste gas desulfurization and denitrification system comprises a dry desulfurization tower (1), a bag-type dust remover (2), a low-temperature SCR (selective catalytic reduction) denitrification system (3) and a booster fan (4), wherein the gas outlet end of the dry desulfurization tower (1) is connected to the gas inlet end of the bag-type dust remover (2), the gas outlet end of the bag-type dust remover (2) is connected to the gas inlet end of the low-temperature SCR denitrification system (3), and the gas outlet end of the low-temperature SCR denitrification system (3) is connected to the gas inlet end of the booster fan (4); the method is characterized in that: the dry desulfurization tower (1) comprises a grinding and conveying system (11), a venturi (12) and a desulfurization tower straight body (13), wherein the output end of the grinding and conveying system (11) is connected with the input end of the venturi (12), and the output end of the venturi (12) is connected with the input end of the desulfurization tower straight body (13); the bag-type dust collector (2) comprises a bag (21), a blowing system (22) and an ash bucket (23), wherein the blowing end of the blowing system (22) is connected to the inner cavity of the bag (21), and the input end of the ash bucket (23) is connected to the dust exhaust end of the bag (21); the bag-type dust collector (2) further comprises an ash conveying system (24) and an ash storage bin (25), wherein the input end of the ash conveying system (24) is connected to the output end of the ash hopper (23), and the input end of the ash storage bin (25) is connected to the output end of the ash conveying system (24).

2. The lime kiln waste gas desulfurization and denitrification system according to claim 1, characterized in that: the low-temperature SCR denitration system (3) comprises a denitration reactor shell (31), an auxiliary heating system (32), an ammonia injection grid (33), a guide plate (34), a flue gas homogenizing module (35) and a denitration catalyst (36), wherein the auxiliary heating system (32), the ammonia injection grid (33), the guide plate (34) and the flue gas homogenizing module (35) are sequentially arranged at the input end of the denitration reactor shell (31), and the denitration catalyst (36) is arranged in a straight body part of the denitration reactor shell (31).