Coupling enhanced electrostatic fabric filter

Abstract

The invention belongs to the field of flue gas dust removal and desulfurization environmental protection, and particularly relates to a coupling enhanced type electric bag composite dust remover, which adopts a two-stage or three-stage different-aperture filtering technology, electric field structures are arranged in front of and behind filter bags, the first stage is a stainless steel metal filter bag, the aperture of the filter bag is large, and 80% of dust can be intercepted; the second stage adopts a fiber woven mesh filter bag, the aperture of the filter bag is medium aperture, and 15% of dust in the original flue gas can be intercepted, and the third stage adopts a fiber woven mesh filter bag, the aperture of the filter bag is small aperture, and 5% of dust in the original flue gas can be intercepted; the electric fields are respectively arranged in front of and behind the second-stage filter bag and the third-stage filter bag, and the charge property of dust is increased by utilizing the front and rear electric fields, so that fluffy and ordered dust layer structures are formed on the surfaces of the second-stage and third-stage fiber woven mesh cloth filter bags, and meanwhile, dust on the surfaces of the filter bags can be captured again by the electric field anode plates when being blown into the front and rear electric fields during blowing; reentrainment of dust can be effectively prevented, and the dust removal efficiency of the dust remover is improved.

Description

Technical Field

[0001] The invention relates to the field of flue gas dust removal, desulfurization and environmental protection, and in particular to a coupled enhanced electric bag composite dust collector. Background Art

[0002] The conventional coal-fired power plant pollutant treatment process route is boiler → denitrification device → heat exchanger → dust collector → desulfurization device → wet electrostatic precipitator → chimney. The dust collector between the existing heat exchanger and the desulfurization device usually adopts an electric bag composite dust collector. The electric bag composite dust collector uses the high-voltage ionization effect of the discharge electrode of the front-stage electrostatic precipitator to ionize a large number of negative ions in the flue gas. The negative ions are adsorbed on the dust in the flue gas, making the dust negatively charged. The negatively charged dust will move toward the grounded anode plate due to the principle of opposites attracting each other, and will eventually be captured by the anode plate, which can Most of the dust can be removed in advance to reduce the dust removal load of the rear bag area, and then the remaining negatively charged dust will move to the rear bag area and finally be filtered and captured by the filter bag. If the filter bag is a fiber mesh filter bag, such as PPS, PI, P84, PTFE and other materials, due to the poor conductivity of these materials, the surface of the filter bag will continue to be negatively charged. Due to the principle of like charges repel each other, the negatively charged dust will form a fluffy and orderly dust layer on the surface of the filter bag, which can effectively reduce the filtration resistance of the filter bag, improve the filtration effect and extend the service life of the filter bag.

[0003] The flue gas temperature at the inlet of the dust collector is generally 100℃-200℃. Since there is a large amount of sulfur dioxide in the coal burned in the boiler, there will be a large amount of sulfur dioxide in the flue gas, and some of the sulfur dioxide will be converted into sulfur trioxide. When the flue gas temperature is lower than the acid dew point (about 80℃ to 150℃), the sulfur trioxide in the flue gas will combine with the water vapor in the flue gas to form sulfuric acid vapor. The sulfuric acid vapor will corrode the fiber mesh filter bag and greatly shorten the life of the filter bag. Therefore, if the fiber mesh filter bag structure is used, the flue gas temperature should generally be guaranteed. Above the acid dew point, the flue gas cannot form a large amount of sulfuric acid vapor. If the filter bag is made of stainless steel, the problem of sulfuric acid vapor corrosion is completely solved. The metal filter bag can withstand a flue gas temperature of 350°C to 400°C, but the stainless steel filter bag has good conductivity. Negative charges cannot continue to accumulate on the surface of the metal filter bag, and a fluffy and orderly dust layer cannot be formed on the surface of the stainless steel filter bag. At the same time, the price of metal filter bags is 4-8 times that of fiber mesh filter bags. Although they have a long lifespan, they are expensive, which limits the use of metal filter bags.

[0004] Some dust collectors use fiber mesh structures, but the flue gas temperature at the flue gas inlet needs to be strictly controlled so that the flue gas temperature is greater than the acid dew point temperature. At the same time, the service life of the fiber mesh filter bag is not long. When the filter bag is damaged, the boiler must be stopped for replacement, which has high shutdown costs and cannot guarantee long-term stable operation. In addition, most existing dust collectors only have a single filter bag filtering effect, and the dust removal efficiency is not high. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention provides a coupled enhanced electric bag composite dust collector, which adopts stainless steel metal filter bags and fiber mesh filter bags to solve the above technical problems.

[0006] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: 1. A coupled enhanced electric bag composite dust collector, characterized in that it includes an inlet flue, an inlet horn, a first bag area, a second bag area and a third bag area, a dust collector housing and an ash hopper; the two ends of the inlet horn are respectively connected to the inlet flue and the first bag area, the first bag area, the second bag area and the third bag area are all arranged in the dust collector housing, and are arranged in sequence according to the direction of the flue gas, and the ash hopper is provided in multiples according to the number of bag areas, and is respectively installed below the first bag area, the second bag area and the third bag area;

[0007] Two airflow distribution plates are arranged in the inlet horn, and a heat exchange device is arranged between the two airflow distribution plates; the first bag area is provided with multiple groups of primary stainless steel metal filter bags, which are made of stainless steel metal and have a large-aperture mesh structure, and multiple groups of the primary stainless steel metal filter bags are installed under a primary flower plate; the second bag area is composed of multiple groups of secondary fiber mesh filter bags and secondary flower plates arranged on the upper end of the secondary fiber mesh filter bags; the secondary fiber mesh filter bags adopt a medium-aperture mesh structure; the third bag area is composed of multiple groups of tertiary fiber mesh filter bags and tertiary flower plates arranged on the upper end of the tertiary fiber mesh filter bags; the tertiary fiber mesh filter bags adopt a fine-aperture mesh structure;

[0008] A clean air chamber is arranged above the first bag area, the second bag area and the third bag area. A pulse spray device is arranged in the middle of each clean air chamber. Each pulse spray device is provided with a plurality of nozzles corresponding to the filter bags in each bag area. A clean air chamber solid partition is arranged between adjacent clean air chambers.

[0009] Furthermore, electric fields are provided before and after the second bag area and the third bag area, and each of the electric fields is composed of two groups of relatively arranged discharge electrodes, two groups of relatively arranged anode dust collecting solid plates, two groups of relatively arranged anode dust collecting hole plates, two groups of relatively arranged electric field solid partitions and an electric field partition hole plate. The two electric field solid partitions are respectively arranged between the first bag area and the second bag area, and between the second bag area and the third bag area; the two groups of electric field partition holes of each electric field are respectively arranged on both sides of the second bag area and the third bag area to separate the bag area from the electric field, and the two groups of anode dust collecting hole plates, discharge electrodes and anode dust collecting solid plates are respectively arranged on the outside of the electric field partition holes, and are arranged in sequence from the inside to the outside.

[0010] Furthermore, the discharge electrode is composed of a cathode frame, a cathode wire and a needle-punched wire, the anode dust collecting solid plate is a solid flat plate structure, and the anode dust collecting orifice plate is an orifice flat plate structure.

[0011] Furthermore, the blowing pressure of the pulse blowing device corresponding to the first-level stainless steel metal filter bag is 0.5MPa, the blowing pressure of the pulse blowing device corresponding to the second-level fiber mesh filter bag is 0.3MPa, and the blowing pressure of the pulse blowing device corresponding to the third-level fiber mesh filter bag is 0.2MPa.

[0012] Furthermore, the secondary fiber mesh filter bag and the tertiary fiber mesh filter bag are made of PPS, PI, PTFE, P84 materials or a composite of several of these materials.

[0013] Furthermore, a certain proportion of holes are opened on the two groups of anode dust collecting orifice plates, and the opening rate is 30-70%.

[0014] Furthermore, the discharge intensity of the discharge pole of the electric field of the second pocket region is greater than the discharge intensity of the discharge pole of the electric field of the third pocket region.

[0015] Furthermore, the secondary flower plate and the tertiary flower plate are flat plate structures with many round holes opened thereon for installing the secondary fiber mesh cloth filter bag and the tertiary fiber mesh cloth filter bag.

[0016] A coupled enhanced electric bag composite dust collector only includes an inlet flue, an inlet horn, a first bag area and a third bag area, a dust collector shell and an ash hopper; the secondary fiber mesh filter bag, the secondary flower plate and the clean air chamber in the second bag area are removed, and the electric field in the second bag area and the ash hopper below are removed.

[0017] Compared with the prior art, the present invention provides a coupled enhanced electric bag composite dust collector, which has the following beneficial effects:

[0018] 1. The present invention adopts multi-stage filtration technology. The first stage is a stainless steel metal filter bag with a large pore size. The large pore size is the particle size for large dust in the flue gas, and its pore size can intercept 80% of the dust. The second stage adopts a fiber mesh filter bag with a medium pore size, which can intercept 15% of the dust in the original flue gas. The third stage adopts a fiber mesh filter bag with a fine pore size, which can intercept 5% of the dust in the original flue gas. The three-stage filtration structure can reduce the use area of ​​the metal filter bag. At the same time, the metal filter bag can filter most of the dust, reduce the filtration load of the rear filter bag, and extend the service life of the filter bag.

[0019] 2. The present invention can be used in low-temperature flue gas, that is, below 80°C, so that a large amount of sulfuric acid vapor is generated before the flue gas passes through the first stage of filtration. The stainless steel metal filter bag is not easy to corrode. At the same time, the dust layer formed on the surface of the stainless steel metal filter bag can effectively intercept the sulfuric acid vapor, so that the subsequent fiber mesh filter bag is basically not corroded by the sulfuric acid vapor.

[0020] 3. The present invention sets electric fields before and after the second-stage filter bag and the third-stage filter bag, respectively, and utilizes the front and rear electric fields to increase the charging performance of dust, so that a fluffy and orderly dust layer structure is formed on the surface of the second-stage and third-stage fiber mesh filter bags. At the same time, the dust on the surface of the filter bag will be blown into the front and rear electric fields during spraying and will be captured again by the electric field anode plates, which can effectively prevent secondary dust and improve the dust removal efficiency of the dust collector.

[0021] 4. The present invention adopts three-level filtration technology with different apertures, and sets an electric field structure before and after the filter bag, which can reduce the filtration resistance and improve the dust removal efficiency. It makes full use of the characteristics of stainless steel metal filter bags, effectively combines the filter bag filtration and electric field dust removal technology, and can meet the requirements of ultra-clean emissions. The dust removal efficiency can reach more than 99.99%, meeting the national standard of dust emission of 10mg / m 3 The requirements can even reach ultra-low emissions of 5mg / m 3 requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a front view of the first embodiment of the present invention;

[0023] Figure 2 A top view of an embodiment of the present invention;

[0024] Figure 3 It is a structural schematic diagram of the first bag area;

[0025] Figure 4 It is a schematic diagram of the structure of the second pocket area and the front and rear electric fields;

[0026] Figure 5 It is a schematic diagram of the third pocket area and the front and rear electric field structures;

[0027] Figure 6 This is a schematic diagram of the large aperture structure of a primary stainless steel metal filter bag;

[0028] Figure 7 It is a schematic diagram of the medium pore size structure of the secondary fiber mesh filter bag;

[0029] Figure 8 It is a schematic diagram of the pore size structure of the three-stage fiber mesh filter bag;

[0030] Fig. 9 This is a front view of the second embodiment of the present invention.

[0031] In the figure: 1 inlet flue; 2 inlet horn; 21 air flow distribution plate; 22 heat exchange device;

[0032] 3 the first bag area; 31 the first level stainless steel metal filter bag; 32 the first level flower plate;

[0033] 4 first-stage clean air chamber; 41 first-stage pulse jet device;

[0034] 5 the first electric field; 51 the first discharge electrode; 52 the first anode dust collecting solid plate; 53 the first anode dust collecting perforated plate; 54 the first electric field solid partition plate; 55 the first electric field perforated plate;

[0035] 6 second bag area; 61 second fiber mesh filter bag; 62 second flower plate;

[0036] 7. Secondary clean air chamber; 71. Secondary pulse jet device; 72. Secondary clean air chamber solid partition;

[0037] 8 second electric field; 81 secondary discharge electrode; 82 secondary anode dust collecting solid plate; 83 secondary anode dust collecting perforated plate; 84 secondary electric field solid partition plate; 85 secondary electric field perforated plate;

[0038] 9 the third bag area; 91 the third-level fiber mesh filter bag; 92 the third-level flower plate;

[0039] 10 third-stage clean air chamber; 101 first-stage pulse jet device; 102 second-stage clean air chamber solid partition;

[0040] 11 dust collector housing; 12 ash hopper. DETAILED DESCRIPTION

[0041] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0042] See also Figure 1-9 In this embodiment: a coupled enhanced electric bag composite dust collector includes an inlet flue 1, an inlet horn 2, a first bag area 3, a primary clean air chamber 4, a first electric field 5, a second bag area 6, a secondary clean air chamber 7, a second electric field 8, a third bag area 9, a tertiary clean air chamber 10, a dust collector housing 11 and an ash hopper 12. The dust collector housing 11 is composed of plates and steel sections, etc., which are spliced ​​into a dust collector shell, columns and beams, etc., and play the role of closing and supporting the dust collector. The ash hopper 12 is composed of three ash hoppers, which are installed at the bottom of the dust collector and play the role of storing ash.

[0043] The two ends of the inlet horn 2 are respectively connected to the inlet flue 1 and the first bag area 3. The first bag area 3, the second bag area 6 and the third bag area 9 are arranged in sequence according to the direction of the flue gas. A first-level clean air chamber 4 is provided above the first bag area 3, a second-level clean air chamber 7 is provided above the second bag area 6, and a third-level clean air chamber 10 is provided above the third bag area 9. There are two groups of first electric fields 5 and second electric fields 8. The two groups of first electric fields 5 are respectively arranged in front and behind the second bag area 6, and the two groups of second electric fields 8 are respectively arranged in front and behind the third bag area 9.

[0044] An air flow distribution plate 21 and a heat exchange device 22 are provided in the inlet horn 2. There are two air flow distribution plates 21. The heat exchange device 22 is arranged between the two air flow distribution plates 21. The flue gas enters the dust collector from the dust collector inlet flue 1. The flue gas temperature is generally above 150°C. The flue gas first passes through the heat exchange device 22 between the air flow distribution plates 21 in the inlet horn 2, which can reduce the flue gas temperature to below 80°C. Then the flue gas will evenly enter the first bag area 3, flow out from the first bag area 3 and enter the upper first-level clean air chamber 4, and then the flue gas will flow downward into the first electric field 5 at the front end of the second bag area 6, and then flow upward through the second bag area 6, and flow out through the first electric field 5 at the rear end of the second bag area 6 into the upper second-level clean air chamber 7; the flue gas will then flow downward into the second electric field 8 of the third bag area 9, and then flow upward through the third bag area 9, and another second electric field 8 is installed at the rear end of the third bag area 9, and the flue gas will flow out from the third bag area 9 into the upper third-level clean air chamber 10, and finally the clean flue gas will be discharged from the rear end of the third-level clean air chamber 10.

[0045] Further as Figure 3 , Figure 6 As shown, the first bag area 3 is composed of multiple groups of first-level stainless steel metal filter bags 31 and first-level flower plates 32. The first-level stainless steel metal filter bags 31 are made of stainless steel metal, which has good strength and hardness, and also has good acid corrosion resistance. The first-level stainless steel metal filter bags 31 adopt a large-aperture mesh structure. The aperture is designed according to the distribution of the dust particle size detected in the original flue gas. Its large-aperture mesh can ensure effective filtration and interception of 80% of the dust. The first-level flower plate 32 is a flat plate structure with many round holes on it for installing the first-level stainless steel metal filter bags 31. The first-level clean air chamber 4 is equipped with a first-level pulse spray device 41 corresponding to the first-level stainless steel metal filter bag 31. The nozzle of each first-level pulse spray device 41 faces the middle of a group of first-level stainless steel metal filter bags 31. Since the first bag area 3 can filter and intercept 80% of the dust, the amount of dust on the surface of the filter bag is large. The first-level pulse spray device 41 uses a spray pressure of 0.5MPa to spray the first-level stainless steel metal filter bag 31, which can effectively remove the dust on the surface of the first-level stainless steel metal filter bag 31.

[0046] Further as Figure 6 The figure shows the mesh structure of the first-stage stainless steel metal filter bag 31. The first-stage stainless steel metal filter bag 31 is made of stainless steel metal. The mesh aperture of the filter bag is relatively large, which can effectively remove about 80% of the dust in the original flue gas dust and reduce the dust removal load of the subsequent stage. The stainless steel metal material has good acid corrosion resistance and can effectively intercept the sulfuric acid vapor formed by the dust collector at low temperature without being corroded.

[0047] Further as Figure 4As shown, a first electric field 5 is provided before and after the second bag area 6. The first electric field 5 is composed of a primary discharge electrode 51, a primary anode dust collecting solid plate 52, a primary anode dust collecting hole plate 53, a primary electric field solid partition plate 54 and a primary electric field hole plate 55. There is only one group of primary electric field solid partition plates 54, which are arranged between the first bag area 3 and the second bag area 6, and are used to isolate the first bag area 3 and the first electric field 5, so as to prevent the flue gas that has not been filtered by the first bag area 3 from horizontally passing through the primary electric field solid partition plate 54 and entering the first electric field 5. There are two groups of primary discharge electrodes 51, primary anode dust collecting solid plates 52, primary anode dust collecting perforated plates 53 and primary electric field partition plates 55, which are arranged opposite to each other. Two primary electric field partition plates 55 are arranged on both sides close to the second bag area 6 to separate the second bag area 6 from the first electric field 5, and the primary anode dust collecting perforated plates 53, primary discharge electrodes 51 and primary anode dust collecting solid plates 52 are arranged on the outside of the primary electric field partition plates 55 of the second bag area 6, and are arranged in sequence from the inside to the outside.

[0048] The primary discharge electrode 51 is composed of a cathode frame, cathode wires and acupuncture wires, etc., and is a conventional cathode structure; the primary anode dust collecting solid plate 52 is a solid flat plate structure, which can effectively capture dust in the flue gas; the primary anode dust collecting perforated plate 53 is a perforated plate structure, on which a certain proportion of holes are opened, and the opening rate is about 30-70%. Its perforated structure allows part of the flue gas captured by the first electric field 5 to directly enter the second bag area 6, reducing the problem of charged dust easily losing charge due to long flight distance, and can effectively enhance the charging performance of dust reaching the surface of the filter bag, strengthen the effect of fluffy and orderly dust layer, and at the same time, when the filter bag is cleaned, it can also allow fine dust that is easy to fly into the first electric field 5 and be re-captured by the electric field to improve the dust removal efficiency. The primary electric field partition plate 55 is mainly used to separate the first electric field 5 and the second bag area 6. Its open hole structure allows the flue gas to pass through. Its structure is the same as that of the primary anode dust collecting plate 53. However, since it is behind the primary anode dust collecting plate 53, it does not undertake the main dust collecting work. Its main function is that the plate can form a flue gas channel, so that part of the flue gas can enter the second bag area 6 from the first electric field 5, or when cleaning, fine dust that is easy to be raised can enter the first electric field 5 from the second bag area 6, and be recaptured by the electric field to improve the dust removal efficiency. At the same time, it should be emphasized that since the first electric field 5 at the rear end of the second bag area 6 is not in the direction of flue gas flow, the cleaning is not affected by the airflow, and the cleaning effect is better. At this time, the opening rate of the primary anode dust collecting plate 53 can be higher than that of the primary anode dust collecting plate 53 at the front end, which is conducive to the raised dust entering the first electric field 5 at the rear end during cleaning.

[0049] Further as Figure 4As shown, the second bag area 6 is composed of a plurality of groups of secondary fiber mesh filter bags 61 and a secondary flower plate 62 arranged at the upper end of the secondary fiber mesh filter bags 61. The secondary fiber mesh filter bags 61 can be made of a composite of materials such as PPS, PI, PTFE, P84, etc., and have certain acid corrosion resistance. The secondary fiber mesh filter bags 61 adopt a medium-aperture mesh structure, and the aperture is designed according to the distribution of the dust particle size detected in the original flue gas. The aperture mesh can ensure effective filtration and interception of 15% of the dust. Due to the use of fiber mesh filter bags, the charged dust on the surface of the filter bag can form a fluffy and orderly dust layer due to the principle of opposites attracting each other, which is conducive to filtering dust, reducing resistance, and improving dust removal efficiency. The secondary flower plate 62 is a flat plate structure with many round holes on it for installing the secondary fiber mesh filter bags 61. The second bag area 6 is above the secondary clean air chamber 7, in the middle of which is installed a secondary pulse spray device 71, and a secondary clean air chamber solid partition 72 is provided on the side close to the primary clean air chamber 4. The secondary pulse spray device 71 is provided with multiple groups corresponding to the secondary fiber mesh filter bag 61, and the nozzle faces the middle of the secondary fiber mesh filter bag 61. Since the second bag area 6 can filter and intercept 15% of the dust, the amount of dust on the surface of the filter bag is large, the secondary pulse spray device 71 should use a medium spray pressure of about 0.3MPa to spray the filter bag, which can effectively remove the dust on the surface of the filter bag. The secondary clean air chamber solid partition 72 separates the primary clean air chamber 4 and the secondary clean air chamber 7 to prevent the smoke from the primary clean air chamber 4 from directly entering the secondary clean air chamber 7.

[0050] Further as Figure 7 As shown, the secondary fiber mesh filter bag 61 adopts a medium-aperture mesh structure, and is made of a composite of materials such as PPS, PI, PTFE, and P84. The mesh of the filter bag is of medium aperture, which can effectively remove about 15% of the dust of medium particle size in the original flue gas dust, reducing the dust removal load of the subsequent stage. The secondary fiber mesh filter bag 61 has certain acid corrosion resistance and weak electrical conductivity, which can block a small amount of sulfuric acid vapor escaping from the primary stainless steel metal filter bag 31, and due to the principle of like charges repel each other, the charged dust will form a fluffy and orderly dust layer effect on the surface of the filter bag, which can effectively reduce the filtration resistance and improve the filtration effect.

[0051] Further as Figure 5As shown, a second electric field 8 is provided before and after the third bag area 9. The second electric field 8 has the same structure as the first electric field 5, and is composed of a secondary discharge electrode 81, a secondary anode dust collecting solid plate 82, a secondary anode dust collecting hole plate 83, a secondary electric field solid partition plate 84 and a secondary electric field partition hole plate 85. There is only one group of secondary electric field solid partition plates 84, which is arranged between the second bag area 6 and the third bag area 9, and is used to isolate the second bag area 6 and the second electric field 8, so as to prevent the flue gas that has not been filtered by the second bag area 6 from horizontally passing through 84 and entering the second electric field 8. There are two groups of secondary discharge electrodes 81, secondary anode dust collecting solid plates 82, secondary anode dust collecting perforated plates 83 and secondary electric field partition plates 85, which are arranged opposite to each other. Two secondary electric field partition plates 85 are arranged on both sides close to the third bag area 9 to separate the third bag area 9 from the second electric field 8, and the secondary anode dust collecting perforated plates 83, secondary discharge electrodes 81 and secondary anode dust collecting solid plates 82 are arranged on the outside of the secondary electric field partition plates 85 of the third bag area 9, and are arranged in sequence from the inside to the outside.

[0052] The secondary discharge electrode 81 is composed of a cathode frame, cathode wires and needle-punched wires, etc., and is a conventional cathode structure; the secondary anode dust collecting solid plate 82 is a solid flat plate structure, which can effectively capture dust in the flue gas; the secondary anode dust collecting perforated plate 83 is a perforated plate structure, on which a certain proportion of holes are opened, and the opening rate is about 30-70%. Its perforated structure allows part of the flue gas captured by the second electric field 8 to directly enter the third bag area 9, reducing the problem of charged dust easily losing charge due to long flight distance, and can effectively enhance the charging performance of dust reaching the surface of the filter bag, and strengthen the effect of fluffy and orderly dust layer. At the same time, when the filter bag is cleaned, fine dust that is easy to be raised can also enter the second electric field 8 and be re-captured by the electric field, thereby improving the dust removal efficiency. The secondary electric field partition plate 85 is mainly used to separate the second electric field 8 and the third bag area 9. Its open hole structure allows the flue gas to pass through. Its structure is the same as that of the primary anode dust collecting plate 83. However, since it is behind the secondary anode dust collecting plate 83, it does not undertake the main dust collecting work. Its main function is that the plate can form a flue gas channel, so that part of the flue gas can enter the third bag area 9 from the second electric field 8, or when cleaning, fine dust that is easy to be raised can enter the second electric field 8 from the third bag area 9, and be recaptured by the electric field to improve the dust removal efficiency. At the same time, it should be emphasized that since the second electric field 8 at the rear end of the third bag area 9 is not in the direction of flue gas circulation, the cleaning is not affected by the airflow, and the cleaning effect is better. At this time, the opening rate of the primary anode dust collecting plate 83 can be higher than that of the secondary anode dust collecting plate 83 at the front end, which is conducive to the dust entering the second electric field 8 at the rear end during cleaning.

[0053] Further as Figure 5As shown, the third bag area 9 is composed of a plurality of groups of three-level fiber mesh filter bags 91 and a three-level flower plate 92 arranged at the upper end of the three-level fiber mesh filter bags 91. The three-level fiber mesh filter bags 91 can be made of a composite of materials such as PPS, PI, PTFE, P84, etc., and have certain acid corrosion resistance. The three-level fiber mesh filter bags 91 adopt a fine-pore mesh structure, and the aperture is designed according to the distribution of the dust particle size detected in the original flue gas, wherein the aperture mesh can ensure effective filtration and interception of 5% of the dust. Due to the use of fiber mesh filter bags, the charged dust on the surface of the filter bag can form a fluffy and orderly dust layer due to the principle of opposites attracting each other, which is conducive to filtering dust, reducing resistance, and improving dust removal efficiency. The three-level flower plate 92 is a flat plate structure with many round holes on it for installing the three-level fiber mesh filter bags 91. A third-level clean air chamber 10 is arranged above the third bag zone 9, a third-level pulse spray device 101 is installed in the middle, and a third-level clean air chamber solid partition 102 is arranged on the side adjacent to the second-level clean air chamber 7. Since the third bag zone can filter and intercept 5% of dust, the amount of dust on the surface of the filter bag is small, and the third-level pulse spray device 101 should use a relatively small spray pressure of about 0.2MPa to spray the filter bag, which can effectively remove the dust on the surface of the filter bag. The third-level clean air chamber solid partition 102 separates the second-level clean air chamber 7 from the third-level clean air chamber 10 to prevent the smoke from the second-level clean air chamber 7 from directly entering the third-level clean air chamber 10.

[0054] Further as Figure 8 As shown, the three-stage fiber mesh filter bag 91 is a fine-pore mesh structure, which is made of PPS, PI, PTFE, P84 and other materials. The mesh aperture of the filter bag is a fine pore diameter, which can effectively remove about 5% of the small and medium-sized dust in the original flue gas dust, and the flue gas is completely purified. The three-stage fiber mesh filter bag 91 has a certain acid corrosion resistance and weak conductivity, which can block the trace escape of sulfuric acid vapor from the first two stages of filter bags, and due to the principle of like charges repel each other, the charged dust will form a fluffy and orderly dust layer effect on the surface of the filter bag, which can effectively reduce the filtration resistance and improve the filtration effect.

[0055] The primary electric field 5 and the secondary electric field 8 have different discharge electrode discharge intensities for different dust quantities and different dust particle sizes. The discharge electrode 51 of the primary electric field 5 has a greater discharge intensity than the discharge electrode 81 of the secondary electric field 8. At the same time, the primary electric field 5 and the secondary electric field 8 also have a certain dust removal capability.

[0056] A coupled enhanced electric bag composite dust collector, the working process of which is as follows:

[0057] (1) Flue gas enters the dust collector from the dust collector inlet flue 1. The flue gas temperature is generally above 150°C. The flue gas first passes through the air flow distribution plate 21 in the inlet horn 2. A heat exchange device 22 is provided between the two air flow distribution plates 21. The heat exchange device 22 can reduce the flue gas temperature to below 80°C to ensure that the flue gas temperature is lower than the acid dew point temperature, so that the sulfur trioxide in the flue gas reacts with water to form sulfuric acid;

[0058] (2) After the smoke is diffused and evenly distributed by the air flow distribution plate 21, the smoke evenly enters the first bag area 3 and is filtered and dusted by the first-stage stainless steel metal filter bag 31. The first-stage stainless steel metal filter bag 31 has a larger pore size and good acid corrosion resistance, and can effectively capture about 80% of the dust in the smoke. At the same time, under the same action of the filter bag and the surface dust layer, the sulfuric acid vapor in the smoke can be effectively captured to prevent the sulfuric acid vapor from entering the subsequent filter bag and corroding the fiber mesh filter bag;

[0059] (3) The flue gas flows out from the bag opening of the primary stainless steel metal filter bag 31 and enters the primary clean air chamber 4. The primary clean air chamber 4 is equipped with a primary pulse spraying device 41, which can spray the primary stainless steel metal filter bag 31. Through the action of the spraying airflow, the dust layer on the surface of the primary stainless steel metal filter bag 31 can fall off, and the dust falls into the ash hopper 12;

[0060] (4) Flue gas enters the primary electric field 5 from the primary clean air chamber 4, where the flue gas is ionized, and the dust is charged and captured by the primary anode dust collecting solid plate 52 and the primary anode dust collecting hole plate 53. Then, part of the flue gas passes through the primary anode dust collecting hole plate 53 and the primary electric field partition hole plate 55 and directly enters the second bag area 6. Part of the flue gas flows from the bottom of the first electric field 5 to the bottom of the second bag area 6. After the flue gas enters the second bag area 6, it is filtered and dusted by the secondary fiber mesh filter bag 61. The secondary fiber mesh filter bag 61 has medium pores and can remove about 15% of the dust in the flue gas. At the same time, the primary electric field 5 is close to the filter bag, which can effectively improve the charging performance of the dust accumulated in the secondary fiber mesh filter bag 61, so that the dust forms a fluffy and orderly dust layer structure, reducing the filtration resistance and improving the filtration effect.

[0061] (5) Flue gas flows out from the secondary fiber mesh filter bag 61 and enters the secondary clean air chamber 7. The secondary clean air chamber 7 is equipped with a secondary pulse spraying device 71, which can spray the secondary fiber mesh filter bag 61 to make the dust layer fall off into the ash hopper 12. Some fine dust will be blown up, causing secondary dust. Since the first electric field 5 is provided before and after the second bag area 6, the fine dust will pass through the primary anode dust collecting orifice plate 53 and the primary electric field partition orifice plate 55 and be blown into the front and rear first electric field 5, and be re-captured by the first electric field 5.

[0062] (6) Flue gas enters the secondary electric field 8 from the secondary clean air chamber 7, where it is ionized and the charged dust is captured by the secondary anode dust collecting solid plate 82 and the secondary anode dust collecting hole plate 83. Then part of the flue gas passes through the secondary anode dust collecting hole plate 83 and the secondary electric field partition hole plate 85 and directly enters the third bag area 9. Part of the flue gas flows from the bottom of the second electric field 8 to the bottom of the third bag area 9. After the flue gas enters the third bag area 9, it is filtered and dusted by the tertiary fiber mesh filter bag 91. The tertiary fiber mesh filter bag 91 has a fine pore size and can remove about 5% of the dust in the flue gas. At the same time, the secondary electric field 8 is close to the filter bag, which can effectively improve the charging performance of the dust accumulated in the tertiary fiber mesh filter bag 91, so that the dust forms a fluffy and orderly dust layer structure, reducing the filtering resistance and improving the filtering effect.

[0063] (7) Flue gas flows out from the three-stage fiber mesh filter bag 91 and enters the three-stage clean air chamber 10. The three-stage clean air chamber 10 is equipped with a three-stage pulse spraying device 101, which can spray the three-stage fiber mesh filter bag 91 to make the dust layer fall off into the ash hopper 12. Some fine dust will be blown up, causing secondary dust. Since the second electric field 8 is provided before and after the third bag area 9, the fine dust will pass through the secondary anode dust collecting orifice plate 83 and the secondary electric field partition orifice plate 85 and be blown into the front and rear second electric field 8, and be re-captured by the first electric field 8. Finally, the flue gas filtered by the three-stage filter bag and the secondary electric precipitator is discharged from the three-stage clean air chamber;

[0064] Further as Fig. 9 As shown, the second embodiment provides another use of a coupled enhanced electric bag composite dust collector, which is different from the first embodiment in that the second embodiment only uses secondary bag filtration and primary electric dust removal, that is, the secondary bag area 6 and the primary electric field 5 of the original first embodiment are removed, and the primary bag area 3, the tertiary bag area 9 and the secondary electric field 8 are retained. The main consideration is that the footprint is smaller and it can be used in small and medium-sized dust collectors or in areas with general emission requirements. The secondary bag filtration and the primary electric dust removal are sufficient to meet the national emission standards.

[0065] In the present invention, the first-stage stainless steel metal filter bag 31 has an 80% dust removal efficiency, the second-stage fiber mesh filter bag 61 has a 15% dust removal efficiency, and the third-stage fiber mesh filter bag 91 has a 5% dust removal efficiency. At the same time, the electric field structure arranged in front and behind has the function of strengthening the dust charging performance, and also has a certain dust removal effect. After multi-stage dust removal, the dust removal efficiency can be guaranteed to reach 99.99%, especially for fine dust that is easy to secondary dust and difficult to remove dust, the problem can be effectively solved.

[0066] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention is described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A coupling enhanced electric bag composite dust collector, characterized in that: It includes an inlet flue, an inlet horn, a first bag area, a second bag area, a third bag area, a dust collector housing and an ash hopper; the two ends of the inlet horn are respectively connected to the inlet flue and the first bag area; the first bag area, the second bag area and the third bag area are all arranged in the dust collector housing and arranged in sequence according to the direction of the flue gas; the ash hopper is provided in multiples according to the number of bag areas, and is respectively installed under the first bag area, the second bag area and the third bag area; Two airflow distribution plates are arranged in the inlet horn, and a heat exchange device is arranged between the two airflow distribution plates; the first bag area is provided with multiple groups of primary stainless steel metal filter bags, which are made of stainless steel metal and have a large-aperture mesh structure, and multiple groups of the primary stainless steel metal filter bags are installed under a primary flower plate; the second bag area is composed of multiple groups of secondary fiber mesh filter bags and secondary flower plates arranged on the upper end of the secondary fiber mesh filter bags; the secondary fiber mesh filter bags adopt a medium-aperture mesh structure; the third bag area is composed of multiple groups of tertiary fiber mesh filter bags and tertiary flower plates arranged on the upper end of the tertiary fiber mesh filter bags; the tertiary fiber mesh filter bags adopt a fine-aperture mesh structure; A clean air chamber is arranged above the first bag area, the second bag area and the third bag area. A pulse spray device is arranged in the middle of each clean air chamber. Each pulse spray device is provided with a plurality of nozzles corresponding to the filter bags in each bag area. A clean air chamber solid partition is arranged between adjacent clean air chambers.

2. The coupling-enhanced electric bag composite dust collector according to claim 1 is characterized in that: Electric fields are provided before and after the second bag area and the third bag area, and each of the electric fields is composed of two groups of discharge electrodes arranged oppositely, two groups of anode dust collecting solid plates arranged oppositely, two groups of anode dust collecting hole plates arranged oppositely, two groups of electric field solid partitions arranged oppositely and an electric field partition hole plate, and the two electric field solid partitions are respectively arranged between the first bag area and the second bag area and between the second bag area and the third bag area; the two groups of electric field partition holes of each electric field are respectively arranged on both sides of the second bag area and the third bag area to separate the bag area from the electric field, and the two groups of anode dust collecting hole plates, discharge electrodes and anode dust collecting solid plates are respectively arranged on the outside of the electric field partition holes, and are arranged in sequence from the inside to the outside.

3. The coupling-enhanced electric bag composite dust collector according to claim 2 is characterized in that: The discharge electrode is composed of a cathode frame, a cathode wire and a needle-punched wire. The anode dust collecting solid plate is a solid flat plate structure. The anode dust collecting orifice plate is an orifice flat plate structure.

4. The coupling-enhanced electric bag composite dust collector according to claim 1 is characterized in that: The blowing pressure of the pulse blowing device corresponding to the first-level stainless steel metal filter bag is 0.5MPa, the blowing pressure of the pulse blowing device corresponding to the second-level fiber mesh filter bag is 0.3MPa, and the blowing pressure of the pulse blowing device corresponding to the third-level fiber mesh filter bag is 0.2MPa.

5. The coupling-enhanced electric bag composite dust collector according to claim 1 is characterized in that: The secondary fiber mesh filter bag and the tertiary fiber mesh filter bag are made of PPS, PI, PTFE, P84 materials or a composite of several of these materials.

6. The coupling-enhanced electric bag composite dust collector according to claim 1 is characterized in that: A certain proportion of holes are opened on the two groups of anode dust collecting hole plates, and the opening rate is 30-70%.

7. The coupling-enhanced electric bag composite dust collector according to claim 5 is characterized in that: The discharge intensity of the discharge pole of the electric field of the second pocket region is greater than the discharge intensity of the discharge pole of the electric field of the third pocket region.

8. The coupling-enhanced electric bag composite dust collector according to claim 1 is characterized in that: The secondary flower plate and the tertiary flower plate are flat plate structures with many round holes for installing the secondary fiber mesh filter bag and the tertiary fiber mesh filter bag.

9. A coupling-enhanced electric bag composite dust collector according to claim 1, characterized in that: It only includes the inlet flue, inlet horn, the first bag area and the third bag area, the dust collector shell and the ash hopper; remove the secondary fiber mesh filter bag, the secondary flower plate and the clean air chamber in the second bag area, and remove the electric field in the second bag area and the ash hopper below.

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