CN217220939U

CN217220939U - SCR denitration system of steel mill sintering machine flue gas

Info

Publication number: CN217220939U
Application number: CN202220546556.0U
Authority: CN
Inventors: 刘一山; 任财轩
Original assignee: Yunnan Qujing Iron And Steel Group Cheng Gang Steel Co ltd
Current assignee: Yunnan Qujing Iron And Steel Group Cheng Gang Steel Co ltd
Priority date: 2022-03-14
Filing date: 2022-03-14
Publication date: 2022-08-19
Anticipated expiration: 2032-03-14

Abstract

The utility model discloses a SCR deNOx systems of steel mill sintering machine flue gas, including GGH gas heater, flue gas heater and SCR reactor, one side of SCR reactor is provided with the standpipe, the lower extreme of standpipe and flue gas heater's the end intercommunication of giving vent to anger, be provided with the ammonia injection grid in the standpipe, the outside of standpipe is provided with the reductant feeding mechanism who communicates with the ammonia injection grid, the upper end of standpipe has set gradually static mixer and 180 degrees elbows, the outlet flue of SCR reactor bottom is connected with flue gas reposition of redundant personnel jar, the outside of flue gas reposition of redundant personnel jar is provided with exhaust-heat boiler, exhaust-heat boiler's steam outlet is connected with steam power generation device, be provided with electric heating element in the flue gas heater, steam power generation device passes through wire and electric heating element intercommunication. The utility model discloses denitration efficiency is high, and difficult jam can reduce running cost, has apparent economic value and social value.

Description

SCR denitration system of steel mill sintering machine flue gas

Technical Field

The utility model relates to a flue gas denitration technical field, concretely relates to SCR deNOx systems of steel mill sintering machine flue gas.

Background

The steel smelting is a high-energy-consumption and heavy-pollution industry, the sintering is one of the most important production process links of a steel combination enterprise, the energy consumption is high, a large amount of high-temperature harmful flue gas is generated, the sintering flue gas is an atmospheric pollutant mainly emitted by the steel enterprise and accounts for more than 50% of the total emission amount of the whole steel enterprise, and the method has great significance in desulfurization, denitrification, dust removal and purification treatment. The main purpose of the sintering flue gas denitration technology is to reduce NOx and dust in the sintering flue gas to be below the latest national environmental protection requirements, reduce the pollution of the emission to the environment, and play an important role in improving the environmental pollution of enterprises and ensuring the production.

The typical processes of denitration of sintering flue gas mainly comprise three processes, namely denitration by an oxidation method, SCR denitration and active coke denitration, wherein the SCR denitration has better energy-saving and emission-reducing effects relatively, and the aim of increasing yield and reducing pollution is easier to realize by iron and steel smelting enterprises. The SCR denitration method is a selective catalytic reduction method technology, and during denitration of sintering flue gas, the sintering flue gas is discharged from a sintering machine and a main shaft fan, then passes through a desulfurization device and a wet electric dust remover to achieve the aims of desulfurization and dust removal, then is heated and heated through a GGH flue gas heat exchanger and a flue gas heater, and finally enters an SCR denitration reactor to be subjected to denitration treatment, so that the aim of flue gas denitration is achieved. The following problems also exist in the actual operation process: firstly, the conventional vanadium-titanium catalyst has poor activity effect in a low-temperature reaction zone, and the denitration efficiency is not high, so that the standard emission cannot be ensured; secondly, when the sintering flue gas is below 300 ℃, the ammonium bisulfate can generate a condensation phenomenon, the catalyst module can be blocked, a stacking adhesion blocking phenomenon is formed, the temperature is periodically increased to be above 300 ℃ for catalyst regeneration, the ammonium bisulfate is pyrolyzed, and a common flue gas heater can not meet the temperature increasing requirement, so that the operation and maintenance cost can be greatly increased; thirdly, the moisture content is great behind the flue gas desulfurization, easily takes place the jam phenomenon, adopts compressed air to sweep often, easily sweeps the dust inside the heat exchanger module, and the pressure loss is great, and deNOx systems's operation energy consumption is great. Therefore, it is objectively needed to develop an SCR denitration system for sintering machine flue gas in a steel mill, which has high denitration efficiency, is not easy to block and can reduce the operation cost.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a denitration efficiency is high, is difficult for blockking up, can reduce the SCR deNOx systems of steel mill sintering machine flue gas of running cost.

The utility model aims to realize the purpose, which comprises a GGH flue gas heat exchanger, flue gas heater and SCR reactor, one side of SCR reactor is provided with the standpipe, the lower extreme of standpipe and flue gas heater's the end intercommunication of giving vent to anger, be provided with the ammonia injection grid in the standpipe, the outside of standpipe is provided with the reductant feeding mechanism with ammonia injection grid intercommunication, the upper end of standpipe has set gradually static mixer and 180 degrees elbows, the other end and the top of SCR reactor of 180 degrees elbows communicate, the outlet flue of SCR reactor bottom is connected with flue gas reposition of redundant personnel jar, the outside of flue gas reposition of redundant personnel jar is provided with exhaust-heat boiler, the outlet flue of flue gas reposition of redundant personnel jar communicates with GGH flue gas heat exchanger's clean flue gas import and exhaust-heat boiler's flue gas import respectively, exhaust-heat boiler's steam outlet is connected with steam power generation facility, be provided with electric heating element in the flue gas heater, steam power generation facility passes through wire and electric heating element intercommunication.

Furthermore, a dust removal and demisting device is arranged on the pipeline at the original smoke inlet end of the GGH smoke heat exchanger.

Furthermore, the reducing agent supply device comprises an ammonia tank and an air-ammonia mixer which are communicated, and an air outlet of the air-ammonia mixer is communicated with the ammonia injection grid.

Furthermore, a heat exchange elbow is arranged in the air-ammonia mixer, and the air inlet end of the heat exchange elbow is communicated with a clean flue gas outlet of the GGH flue gas heat exchanger.

Furthermore, two ends of the static mixer are respectively connected with the vertical pipe and the 180-degree elbow through flanges.

Further, a temperature sensor is arranged in the flue gas heater.

Furthermore, an acoustic wave soot blower is arranged on the outer side of the SCR reactor, and an air outlet of the acoustic wave soot blower is communicated with a catalyst layer in the SCR reactor.

The utility model discloses when using, the sintering flue gas after wet flue gas desulfurization gets into GGH gas heater and carries out primary heating, then get into the gas heater and carry out the secondary heating, sintering flue gas temperature after twice heating promotes to the temperature that the SCR reactor required, get into the SCR reactor after, nitrogen element in the flue gas reacts with ammonia under the effect of catalyst and generates nitrogen gas, reach the purpose of denitration, the clean flue gas temperature after the denitration is higher, divide into two strands with it, one strand lets in GGH gas heater, both can carry out waste heat recovery to the clean flue gas after the denitration, can heat the sintering flue gas that needs to handle again and heat up; the other strand is led into a waste heat boiler, steam is generated by using waste heat in the clean flue gas, the steam is used for enabling the steam power generation device to work to generate power, electric energy is sent into an electric heating element in the flue gas heater, and the electric heating element can heat the sintering flue gas to be treated. Above-mentioned in-process, under the prerequisite that does not increase extra energy consumption, make full use of after the denitration waste heat in the clean flue gas, use GGH gas heater and flue gas heater respectively to heat the sintering flue gas that needs to handle, can promote the temperature of flue gas temperature to the denitration demand on the one hand, guarantee that SCR reactor internal catalyst has better activity to improve denitration efficiency, on the other hand also can prevent that the flue gas from taking place the dewfall phenomenon, cause the jam problem, at last, the utility model discloses in not increasing extra energy consumption, can play energy saving and consumption reduction's effect, and then reduced the denitration cost. The utility model discloses denitration efficiency is high, and difficult jam can reduce running cost, has apparent economic value and social value.

Drawings

Fig. 1 is a schematic view of the overall structure of the present invention;

in the figure: the device comprises a 1-GGH flue gas heat exchanger, a 2-flue gas heater, a 3-SCR reactor, a 4-vertical pipe, a 5-ammonia spraying grid, a 6-static mixer, a 7-180-degree elbow, an 8-flue gas shunt tank, a 9-waste heat boiler, a 10-steam power generation device, an 11-electric heating element, a 12-dedusting and demisting device, a 13-ammonia tank, a 14-air ammonia mixer, a 15-heat exchange elbow, a 16-flange, a 17-temperature sensor, an 18-acoustic wave soot blower and a 19-catalyst layer.

Detailed Description

The present invention will be further described with reference to the accompanying drawings, but the present invention is not limited in any way, and any changes or improvements based on the present invention are all within the protection scope of the present invention.

As shown in figure 1, the utility model comprises a GGH flue gas heat exchanger 1, a flue gas heater 2 and an SCR reactor 3, wherein the GGH flue gas heat exchanger 1 and the SCR reactor 3 are both the existing equipment, the GGH flue gas heat exchanger 1 is used for heating desulfurized flue gas to raise the temperature of the flue gas to the temperature meeting the denitration requirement, a catalyst is arranged in the SCR reactor 3, after the mixed gas of the flue gas and ammonia gas is introduced into the SCR reactor 3, under the catalytic action of the catalyst, nitrogen elements in the flue gas can react with the ammonia gas to generate nitrogen gas, the purpose of flue gas denitration is achieved, one side of the SCR reactor 3 is provided with a vertical pipe 4, the lower end of the vertical pipe 4 is communicated with the gas outlet end of the flue gas heater 2, an ammonia injection grid 5 is arranged in the vertical pipe 4, a reducing agent supply device communicated with the ammonia injection grid 5 is arranged on the outer side of the vertical pipe 4, the reducing agent supply device is the existing equipment and is used for providing the ammonia gas, the upper end of the vertical pipe 4 is provided with a static mixer 6 and a 180-degree elbow 7 in sequence, the static mixer 6 is the existing equipment, used for mixing flue gas and ammonia gas and improving the denitration efficiency of the system, the other end of the 180-degree elbow 7 is communicated with the top of the SCR reactor 3, a flue gas shunt tank 8 is connected with a flue gas outlet at the bottom of the SCR reactor 3, a waste heat boiler 9 is arranged at the outer side of the flue gas shunt tank 8, the waste heat boiler 9 is used for absorbing waste heat in denitration clean flue gas and producing high-temperature steam, the flue gas outlet of the flue gas shunt tank 8 is respectively communicated with a clean flue gas inlet of the GGH flue gas heat exchanger 1 and a flue gas inlet of the waste heat boiler 9, a steam outlet of the waste heat boiler 9 is connected with a steam power generation device 10, and the steam power generation device 10 is the existing device, the flue gas heating device is used for generating electricity, an electric heating element 11 is arranged in the flue gas heater 2, and the steam generating device 10 is communicated with the electric heating element 11 through a conducting wire.

The utility model discloses when using, the sintering flue gas after wet flue gas desulfurization gets into GGH gas heater 1 and carries out primary heating, then get into gas heater 2 and carry out the secondary heating, sintering flue gas temperature after twice heating promotes to the temperature that SCR reactor 3 required, get into SCR reactor 3 after, nitrogen element in the flue gas reacts with ammonia under the effect of catalyst and generates nitrogen gas, reach the purpose of denitration, the clean flue gas temperature after the denitration is higher, divide into two strands with it, one strand lets in GGH gas heater 1, can both carry out waste heat recovery to the clean flue gas after the denitration, can heat the sintering flue gas that needs to handle again and heat up; the other strand is led into a waste heat boiler 9, steam is generated by using waste heat in the clean flue gas, the steam is used for enabling a steam power generation device to work to generate power, electric energy is sent to an electric heating element 11 in the flue gas heater 2, and the electric heating element 11 can heat sintering flue gas to be treated. Above-mentioned in-process, under the prerequisite that does not increase extra energy consumption, make full use of after the denitration waste heat in the clean flue gas, use GGH gas heater 1 and gas heater 2 to heat the sintering flue gas that needs to handle respectively, can promote the temperature of gas temperature to the denitration demand on the one hand, guarantee that SCR reactor 3 internal catalyst has better activity to improve denitration efficiency, on the other hand also can prevent that the flue gas from taking place the dewfall phenomenon, cause the jam problem, last, the utility model discloses in do not increase extra energy consumption, can play energy saving and consumption reduction's effect, and then reduced the denitration cost. When the system starts the operation for the first time, can insert factory building power supply pipeline with electric heating element 11, utilize current electric energy to heat the sintering flue gas, move a period, can break off factory building power supply pipeline after having the clean flue gas of denitration to produce, utilize the utility model discloses self power generation facility power supply.

Be provided with dust removal defogging equipment 12 on the pipeline of the former flue gas entrance point of GGH gas heat exchanger 1, dust removal defogging equipment 12 is existing equipment, but formula structure as an organic whole because desulfurization sintering flue gas still contains moisture and dust, uses dust removal defogging equipment 12 to detach moisture and dust to guarantee the long-term normal operating of back denitration process.

The reducing agent supply device comprises an ammonia tank 13 and an air ammonia mixer 14 which are communicated, an air outlet of the air ammonia mixer 14 is communicated with the ammonia injection grid 5, and the air ammonia mixer 14 is existing equipment and used for mixing air and ammonia gas to achieve the purpose of ammonia gas dilution.

Be provided with heat transfer return bend 15 in the air ammonia blender 14, the concrete structure of heat transfer return bend 15 can be snakelike, the tubular isotructure of helical coil, the heat transfer of being convenient for can, the air inlet end of heat transfer return bend 15 and GGH gas heater 1's clean flue gas export intercommunication, the clean flue gas after the denitration is sent into in the heat transfer return bend 15, utilizes remaining waste heat in the clean flue gas to preheat air ammonia gas mixture, improves air ammonia gas mixture's temperature.

In order to facilitate the disassembly and assembly of the static mixer 6, the lower end of the static mixer 6 is connected with the vertical pipe 4, the upper end of the static mixer 6 is connected with the 180-degree elbow 7 through the flange 16, and other types of connecting structures can be adopted according to actual needs during actual use.

Be provided with temperature sensor 17 in the flue gas heater 2, can make things convenient for the staff to master the temperature of flue gas in the flue gas heater 2 through temperature sensor 17.

The outside of SCR reactor 3 is provided with sound wave soot blower 18, and the gas outlet of sound wave soot blower 18 communicates with catalyst layer 19 in SCR reactor 3, and sound wave soot blower 18 is current equipment for prevent catalyst surface collection ash caking, solve the problem of catalyst jam.

Claims

1. The SCR denitration system for the flue gas of the sintering machine in the steel mill comprises a GGH flue gas heat exchanger (1), a flue gas heater (2) and an SCR reactor (3), and is characterized in that a vertical pipe (4) is arranged on one side of the SCR reactor (3), the lower end of the vertical pipe (4) is communicated with the gas outlet end of the flue gas heater (2), an ammonia injection grid (5) is arranged in the vertical pipe (4), a reducing agent supply device communicated with the ammonia injection grid (5) is arranged on the outer side of the vertical pipe (4), a static mixer (6) and a 180-degree elbow (7) are sequentially arranged at the upper end of the vertical pipe (4), the other end of the 180-degree elbow (7) is communicated with the top of the SCR reactor (3), a flue gas outlet at the bottom of the SCR reactor (3) is connected with a flue gas diversion tank (8), a waste heat boiler (9) is arranged on the outer side of the flue gas diversion tank (8), and a flue gas outlet of the flue gas diversion tank (8) is respectively communicated with a clean flue gas inlet and a waste heat boiler (3) of the GGH flue gas heat exchanger (1) 9) The flue gas inlet of the waste heat boiler (9) is communicated, a steam outlet of the waste heat boiler (9) is connected with a steam generating set (10), an electric heating element (11) is arranged in the flue gas heater (2), and the steam generating set (10) is communicated with the electric heating element (11) through a lead.

2. The SCR denitration system of steel mill sintering machine flue gas according to claim 1, characterized in that a dedusting and demisting device (12) is arranged on the pipeline of the raw flue gas inlet end of the GGH flue gas heat exchanger (1).

3. The SCR denitration system of steel mill sintering machine flue gas according to claim 1, wherein the reducing agent supply device comprises an ammonia tank (13) and an air-ammonia mixer (14) which are communicated, and an air outlet of the air-ammonia mixer (14) is communicated with the ammonia injection grid (5).

4. The SCR denitration system of steel mill sintering machine flue gas according to claim 3, characterized in that a heat exchange elbow (15) is arranged in the air-ammonia mixer (14), and the air inlet end of the heat exchange elbow (15) is communicated with the clean flue gas outlet of the GGH flue gas heat exchanger (1).

5. The SCR denitration system of steel mill sintering machine flue gas according to claim 1, wherein the lower end of the static mixer (6) is connected with the vertical pipe (4), and the upper end of the static mixer (6) is connected with the 180-degree elbow (7) through flanges (16).

6. The SCR denitration system of steel mill sintering machine flue gas according to claim 1, characterized in that a temperature sensor (17) is arranged in the flue gas heater (2).

7. The SCR denitration system of steel mill sintering machine flue gas according to claim 1, characterized in that a sound wave soot blower (18) is arranged outside the SCR reactor (3), and the gas outlet of the sound wave soot blower (18) is communicated with a catalyst layer (19) in the SCR reactor (3).