CN204996282U - An integrated device for flue gas dust and NOX ultra-low emission - Google Patents

Abstract

An integrated device for flue gas dust and NO _X ultra-low emission, which relates to dust removal and denitrification of industrial flue gas. There are intake smoke box, casing, electric field dust removal partition, filter bag dust removal partition, clean air chamber, outlet smoke box, exhaust pipe and bracket; electric field dust removal partition, filter bag dust removal partition, and clean air chamber are set in the casing , the flue gas inlet of the electric field dust removal partition is connected to the flue gas outlet of the intake smoke box, and the flue gas inlet of the filter bag dust removal partition is connected to the flue gas outlet of the electric field dust removal partition; Mixing area, ammonia gas supply device and denitrification device, the filter bag dust removal system is installed at the flue gas outlet of the filter bag dust removal area, the ammonia gas inlet of the ammonia gas and flue gas mixing area is connected to the ammonia gas outlet of the ammonia gas supply device, and the ammonia gas and flue gas are mixed The ammonia flue gas mixed gas outlet in the area is connected to the ammonia flue gas mixed gas inlet of the denitrification device, the flue gas outlet of the denitrification device is connected to the flue gas inlet of the outlet smoke box, and the flue gas outlet of the outlet smoke box is discharged through the exhaust pipe; The bracket is located at the bottom of the casing.

Description

An integrated device for flue gas dust and NOX ultra-low emission

technical field

The utility model relates to dust removal and denitrification of industrial flue gas, in particular to an integrated device for flue gas dust and _NOx ultra-low emission.

Background technique

At present, the contradiction between economic and social development and resource and environmental constraints has become increasingly prominent, and environmental protection is facing increasingly severe challenges. One of the main factors causing air pollution is the discharge of a large amount of dust and harmful gases into the atmosphere from the combustion of coal and other materials in the process of thermal power, cement, steel and other industrial production. Therefore, the purification of harmful pollutants in the industrial production process is one of the main measures to prevent and control air pollution and improve environmental quality. Dust removal and denitrification devices are widely used important environmental protection equipment. According to the Coal Power Energy Conservation and Emission Reduction Upgrading and Transformation Action Plan (2014-2020) ^[1] and the Ministry of Environmental Protection's preparation of the "13th Five-Year Plan" coal-fired power plant ultra-low emission transformation plan ^[2] , these equipment must reach Dust <5mg/Nm ³ , SO ₂ <35mg/Nm ³ , NO _X <50mg/Nm ³ emission standards.

The electrostatic precipitator is a high-efficiency dust removal device that realizes flue gas purification by means of dust being charged in the electric field and deposited on the anode plate under the action of the electric field force. Particles are then difficult to collect, making it difficult to meet ultra-low emission requirements. The filter capacity of the bag filter is closely related to the concentration of flue gas dust before entering the filter bag. The test shows that it is difficult to meet the requirement of ultra-low emission when the inlet concentration is more than 10g/m ³ . Therefore, the bag filter cannot achieve ultra-low emissions under most conditions.

The electric bag composite dust collector developed in China at the end of the last century is a new type of dust removal device developed by absorbing the advantages of the traditional electrostatic dust removal mechanism and bag dust removal mechanism and overcoming their respective shortcomings. m ³ ), low power consumption, and can be widely adapted to various coal qualities of coal-fired power plants, so that the dust collector can run stably for a long time. The electric bag composite dust collector can make the dust concentration entering the bag area less than 10g/m ³ for any coal quality, so that the filter bag dust removal area can meet the ultra-low emission requirement of less than 10mg/m ³ .

The content of NO _X in flue gas is the main cause of acid rain, which seriously endangers human health and crops. In order to solve the hazards of NO _X in flue gas, the state has successively issued relevant policies in the past 10 years, and industrial production enterprises have also appeared SNCR or SCR denitrification methods to reduce the NO _X content within the specified range (such as coal-fired power plants to 50mg/ m ³ ). However, due to historical reasons or some technical problems, the denitrification device of coal-fired power plants is generally installed at the outlet of the boiler economizer. Although the flue gas temperature here meets the requirements of the denitrification chemical reaction (350-400°C), it contains high concentrations of dust. The direct entry of flue gas into the denitrification device will cause blockage and wear of the denitrification catalyst, which will greatly reduce the service life of the catalyst, increase maintenance costs, shorten maintenance cycles, and affect the power generation efficiency of the power plant.

references:

1. Fagai Energy [2014] No. 2093 "Notice on Printing and Distributing the Action Plan for Upgrading and Transformation of Coal Power Energy Conservation and Emission Reduction (2014-2020)".

2. The Ministry of Environmental Protection's "Notice on Compiling the "13th Five-Year Plan" Coal-fired Power Plant Ultra-Low Emission Transformation Plan".

Contents of the invention

The purpose of this utility model is to solve the above-mentioned problems existing in the existing denitrification device, and provide a device that can remove most of the dust before the flue gas flows into the denitrification device, so that the catalyst is not blocked and worn by dust, and greatly prolongs the service life of the catalyst. Flue gas dust and NO _X ultra-low emission integrated device.

The utility model is provided with an intake smoke box, a casing, an electric field dust removal partition, a filter bag dust removal partition, a clean air chamber, a gas outlet smoke box, an exhaust pipe and a bracket; Air source, electric field dust removal partition, filter bag dust removal partition, and clean air chamber are set in the casing, the flue gas inlet of the electric field dust removal partition is connected to the flue gas outlet of the intake box, and the flue gas inlet of the filter bag dust removal partition is connected to the electric field dust removal partition The flue gas outlet; the clean air chamber is equipped with a filter bag dust removal system, an ammonia gas flue gas mixing area, an ammonia gas supply device and a denitration device from bottom to top, and the filter bag dust removal system is installed at the flue gas outlet of the filter bag dust removal partition , the ammonia gas inlet of the ammonia flue gas mixing zone is connected to the ammonia gas outlet of the ammonia gas supply device, the ammonia gas flue gas mixed gas outlet of the ammonia gas flue gas mixing zone is connected to the ammonia gas flue gas mixed gas inlet of the denitrification device, and the ammonia gas flue gas mixture inlet of the denitrification device The flue gas outlet is connected to the flue gas inlet of the exhaust smoke box, and the flue gas outlet of the exhaust smoke box is discharged through the exhaust pipe; the bracket is arranged at the bottom of the casing.

An airflow distribution plate may be arranged in the air intake box.

The electric field dust removal partition can be provided with at least 10 dust collecting plates, corona wires and electric dust buckets, the corona wires are arranged between adjacent dust collection plates, and the electric dust bucket is located at the bottom of the electric field dust removal partition.

The filter bag dedusting section can be provided with a filter bag, a bag cage and a dust hopper in the bag area, the bag cage is arranged in the filter bag, and the ash hopper in the bag area is located at the bottom of the dust removal section of the filter bag.

The filter bag cleaning system can be equipped with nozzles, blowing pipes, air distribution boxes, pulse valves, and compressed air inlets. The nozzles are installed on the blowing pipes, and one end of the blowing pipes is connected to the air distribution box. on the gas box.

The electric field dust removal partition works under high temperature conditions, the temperature is 350-400°C. Under high temperature conditions, the specific resistance of dust is much lower than that at low temperature (about 150°C), so that the driving speed is doubled under the action of electric field force, which can improve the dust removal efficiency of the electric field dust removal partition.

Stainless steel metal filter material can be used in the dust removal area of the filter material. The dust-facing surface is made of 10μm stainless steel felt, while the back-dust surface is made of 30μm felt, with a weight of more than 1000g/ ^m2 . Tested by the VDI filter material performance testing machine, the emission can be within the range of <1mg/m ³ .

Since the denitrification device is set in the clean air chamber above the filter bag dust removal area, the electric bag composite dust removal area originally has strict requirements on the airflow uniformity of the filter bags (the flow deviation between each room is <±5%, and each filter bag indoor , the root mean square deviation of the flow rate of the filter bag σ<0.2), so that the airflow entering the denitrification device has a good uniform distribution performance, which is much better than the uniform distribution effect of the general-purpose denitrification device only relying on the grid distribution plate at the inlet end .

The rising velocity of the airflow in the clean gas chamber is generally 1.0-1.2m/s, which is much lower than the flow velocity (4-5m/s) of the airflow in the conventional denitrification device. In this way, it is easier to increase the residence time of the flue gas passing through the denitrification device (>0.5s), prolong the contact time between the flue gas and the catalyst, and strengthen the chemical reaction of the denitrification process.

In the clean air chamber, the airflow through the denitrification device flows from bottom to top, and the dust concentration in the flue gas is extremely low (can be <10mg/m ³ ), so the erosion and wear of the dust in the flue gas on the denitrification catalyst are greatly reduced , blockage and other failures. It will greatly prolong the service life of the catalyst.

Compared with the prior art, the utility model has the following remarkable advantages:

(1) Integrating dust removal and denitrification in one housing greatly simplifies the process flow;

(2) Adopting the structure of dust removal first and then denitrification can avoid the failure of dust to wash out, wear and block the denitrification catalyst, and greatly prolong the service life of the catalyst;

(3) The use of electric bag composite dust removal area can ensure ultra-low emission of dust (<10mg/m ³ ), which is difficult for general dust removal devices to achieve.

(4) The heat exchange efficiency of the air preheater at the tail end can be greatly improved.

The utility model can be used in the flue gas treatment system of coal-fired power plants, and can also be used in the flue gas treatment of industrial kilns (such as glass melting furnaces).

Description of drawings

Fig. 1 is the structural representation of the utility model embodiment;

Fig. 2 is the A-A sectional view of Fig. 1;

Fig. 3 is the B-B sectional view of Fig. 1;

Fig. 4 is a working schematic diagram of the filter bag cleaning system of the embodiment of the invention.

detailed description

The following embodiments will further illustrate the utility model in conjunction with the accompanying drawings.

Referring to Figures 1 to 4, the embodiment of the utility model is provided with an intake smoke box 1, a casing 2, an electric field dust removal partition 3, a filter bag dust removal partition 4, a clean air chamber 5, an exhaust smoke box 6, an exhaust pipe 7 and a bracket 8. The intake smoke port 11 of the intake smoke box 1 receives and processes the smoke source, the electric field dust removal partition 3, the filter bag dust removal partition 4, and the clean air chamber 5 are set in the casing 2, and the smoke from the electric field dust removal partition 3 The gas inlet is connected to the flue gas outlet of the air intake box 1, and the flue gas inlet of the filter bag dust removal partition 4 is connected to the flue gas outlet of the electric field dust removal partition 3; Gas and flue gas mixing area 52, ammonia gas supply device 54 and denitrification device 53, filter bag dust removal system 51 is installed at the flue gas outlet of filter bag dust removal zone 4, ammonia gas inlet of ammonia gas and flue gas mixing area 52 is connected to ammonia gas supply The ammonia gas outlet of the device 54, the ammonia flue gas mixed gas outlet of the ammonia flue gas mixing zone 52 is connected to the ammonia flue gas mixed gas inlet of the denitrification device 53, and the flue gas outlet of the denitrification device 53 is connected to the flue gas of the smoke box 6 The smoke outlet of the inlet and outlet smoke box 6 is discharged through the exhaust pipe 7; the bracket 8 is arranged at the bottom of the casing 2.

An airflow distribution plate 12 may be provided in the air intake box 1 .

The electric field dust removal partition 3 can be provided with at least 10 dust collecting plates 31, corona wires 32 and electric area ash hoppers 33, the corona wires 32 are arranged between adjacent dust collecting plates 31, and the electric area ash hoppers 33 are located in the electric field Dust extraction partition 3 bottom.

The filter bag dust removal section 4 can be provided with a filter bag 41, a bag cage 42 and a bag area ash hopper 43, the bag cage 42 is arranged in the filter bag 41, and the bag area ash hopper 43 is located at the bottom of the filter bag dust removal area 4.

The filter bag cleaning system 51 can be provided with a nozzle 511, a blowing pipe 512, an air distribution box 513, a pulse valve 514, and a compressed air inlet 515. The nozzle 511 is installed on the blowing pipe 512, and one end of the blowing pipe 512 is connected to the air distribution box 513 , the pulse valve 514 and the compressed air inlet 515 are located on the gas distribution box 513 .

The electric field dust removal partition 3 works under high temperature conditions, the temperature is 350-400°C. Under high temperature conditions, the specific resistance of dust is much lower than that at low temperature (about 150°C), so that the driving speed is doubled under the action of electric field force, which can improve the dust removal efficiency of the electric field dust removal partition.

Stainless steel metal filter material can be used in the dust removal area of the filter material. The dust-facing surface is made of 10μm stainless steel felt, while the back-dust surface is made of 30μm felt, with a weight of more than 1000g/ ^m2 . Tested by the VDI filter material performance testing machine, the emission can be within the range of <1mg/m ³ .

Since the denitrification device is installed in the clean air chamber above the filter bag dust removal area, the electric bag composite dust removal area originally has strict requirements on the airflow uniformity of the filter bag. (The flow deviation value between each chamber is <±5%, and the root mean square deviation of the flow rate of the filter bag in each filter bag room is σ<0.2), so that the airflow entering the denitrification device has a good uniform performance, which is better than the general-purpose The denitrification device only relies on the uniform distribution of the grid distribution plate at the inlet end, which is much better.

The rising velocity of the airflow in the clean gas chamber is generally 1.0-1.2m/s, which is much lower than the flow velocity (4-5m/s) of the airflow in the conventional denitrification device. In this way, it is easier to increase the residence time of the flue gas passing through the denitrification device (>0.5s), prolong the contact time between the flue gas and the catalyst, and strengthen the chemical reaction of the denitrification process.

In the clean air chamber, the airflow through the denitrification device flows from bottom to top, and the dust concentration in the flue gas is extremely low (can be <10mg/m ³ ), so the erosion and wear of the dust in the flue gas on the denitrification catalyst are greatly reduced , blockage and other failures. It will greatly prolong the service life of the catalyst.

The utility model can realize ultra-low (<10mg/m ³ ) emission of dust in the flue gas, and at the same time, the NO _X content in the flue gas can be reduced to below 50 mg/m ³ through the denitrification device, so that the dust in the flue gas Dust and NO _X emissions meet the requirements stipulated in the July 2015 Ministry of Environmental Protection notice.

Since the denitrification device of the present invention is arranged at the rear end of the purified airflow, the denitrification catalyst is not affected by dust erosion, wear, blockage, etc. during operation, and the service life of the catalyst is greatly extended.

The dust-laden smoke enters from the intake smoke box 1 at the left end of the casing 2, and enters the electric field dust removal partition 3 of the electric bag composite dust removal area after being evenly distributed by the air flow distribution plate in the intake smoke box. The dust is charged in the electric field dust removal zone 3, and under the action of the electric field force, most of the dust (about 85% to 90%) is collected by the dust collecting plate 31, and the remaining small amount of charged dust that has not been collected enters the electric bag for recombination Filter bag dust removal partition 4 in the dust removal area. The dust-laden flue gas enters the inner cavity of the filter bag from the outside of the filter bag 41. Under the filtering action of the filter bag, almost all the remaining dust in the flue gas is trapped (dust concentration <10mg/m ³ ), which meets the requirements of the Ministry of Environmental Protection notice. requirements. The pure flue gas continues to enter the upper clean gas chamber 5. The above-mentioned electric field dust removal partition 3 and filter bag dust removal partition 4 are collectively called the electric bag composite dust removal area. It is different from the combination of the general electrostatic precipitator and the bag dust collector. It organically combines the advantages of the two and can exert the coupling effect of the two. , to achieve the effect of 1+1>2.

When the filter bag dust removal partition works, the outer surface of the filter bag will gradually accumulate a layer of dust over time, hindering the filtration of the filter bag. For this reason, a blowing pipe 512 is installed above each row of filter bags, and several nozzles 511 are installed on the blowing pipe, each nozzle is aimed at a filter bag, and one end of the blowing pipe is connected with an air distribution box 513, and there is a Pulse valve 514 and compressed air inlet 515. When the filter bag needs to be cleaned, the automatic pulse controller will activate the pulse valve, and the diaphragm in the pulse valve will act instantaneously (about 150ms), so that the compressed air in the air distribution box will be sprayed into the inner cavity of the filter bag through the blowing pipe and nozzle , the high-pressure gas passing through the filter bag in reverse will effectively remove the dust on the outer surface of the filter bag.

Ammonia gas supply device 54 is installed on the outside of the shell of clean gas chamber 5. When the equipment is working, ammonia gas will enter the lower part of the clean gas chamber through the pipeline, and evenly mix with flue gas in ammonia gas and flue gas mixing area 52. After the mixed flue gas continues to rise and passes through the denitrification device 53, the _NOx and _NH3 in the flue gas will react strongly to form _N2 and _H2O , thereby completing the denitrification process. The flue gas is discharged from the upper gas outlet smoke box 6 after dust removal and denitrification.

Claims (6)

1. An integrated device for flue gas dust and NO _x ultra-low emissions, characterized in that it is provided with an intake smoke box, a casing, an electric field dust removal partition, a filter bag dust removal partition, a clean air chamber, an outlet smoke box, and an exhaust pipe and the bracket; the air inlet of the air intake smoke box receives and processes the smoke source outside, the electric field dust removal partition, the filter bag dust removal partition, and the clean air chamber are arranged in the casing, and the smoke inlet of the electric field dust removal partition is connected to the smoke intake box The flue gas outlet of the filter bag dust removal area is connected to the flue gas outlet of the electric field dust removal area; the clean gas room is equipped with a filter bag dust removal system, an ammonia gas flue gas mixing area, an ammonia gas supply device and a denitrification system from bottom to top. device, the filter bag dust removal system is installed at the flue gas outlet of the filter bag dust removal section, the ammonia gas inlet of the ammonia gas and flue gas mixing area is connected to the ammonia gas outlet of the ammonia gas supply device, and the ammonia gas and flue gas mixing area of the ammonia gas and flue gas mixing area The gas outlet is connected to the ammonia flue gas mixture inlet of the denitrification device, the flue gas outlet of the denitrification device is connected to the flue gas inlet of the exhaust smoke box, and the flue gas outlet of the exhaust smoke box is discharged through the exhaust pipe; the bracket is arranged at the bottom of the casing. 2. An integrated device for flue gas dust and _NOx ultra-low emission according to claim 1, characterized in that an airflow distribution plate is arranged inside the air intake smoke box. 3. A kind of flue gas dust and NO _X ultra-low emission integrated device as claimed in claim 1, it is characterized in that the electric field dedusting partition is provided with at least 10 dust collecting plates, corona wires and electric area ash hoppers, The halo line is set between adjacent dust collecting plates, and the dust hopper in the electric field is located at the bottom of the electric field dust removal partition. 4. A kind of flue gas dust and NO _X ultra-low emission integrated device as claimed in claim 1, it is characterized in that said filter bag dedusting partition is provided with filter bag, bag cage and bag area ash hopper, bag cage is located at filter Inside the bag, the dust hopper in the bag area is located at the bottom of the dust removal partition of the filter bag. 5. A flue gas dust and NO _X ultra-low emission integrated device as claimed in claim 1, characterized in that the filter bag cleaning system is provided with nozzles, blowing pipes, gas distribution boxes, pulse valves, and compressed air inlets , The nozzle is installed on the blowing pipe, one end of the blowing pipe is connected to the gas distribution box, and the pulse valve and compressed air inlet are set on the gas distribution box. 6. An integrated device for flue gas dust and NO _X ultra-low emission according to claim 1, characterized in that the temperature of the electric field dust removal sub-area is 350-400°C.